Dissertations / Theses on the topic 'Atmospheric processing'

The chemistry of aerosol particles is critical to the influence said particles have over human health, air quality and the distribution of nutrients across the world. Current models estimate that windborne dust represents the movement of thousands of teragrams of solid material of varying composition and solubility across continents and into the world’s oceans. Understanding the composition and surface reactivity of anthropogenic particles from industry, agriculture and vehicle emissions is vital to understanding their potential impact on the world, and the structure and behaviour of inhalable pharmaceuticals is a strong determinant of their efficacy. The following work examines a broad selection of natural and anthropogenic particulate samples with synchrotron-based techniques, including analysis of ship emissions collected directly from stacks for the first time. The effect of simulated atmospheric acid processing on the solubility of iron on coal fly ash is evaluated, and optical trapping is used in conjunction with analytical techniques to observe the influence of relative humidity on the properties of pharmaceutical aerosols and aqueous droplets containing fluorescent protein solutions.

O conhecimento atual diz-nos que a atmosfera da Terra em si aprensenta-se como um circuito elétrico global, que proporciona uma atmosfera continuamente eletrificada. O estudo deste circuito global, bem como os efeitos, globais e locais, sobre a componente vertical do campo eléctrico atmosférico, geralmente designada como gradiente de potencial, são de grande importância não só devido à resposta dinâmica do gradiente de potencial em relação a estes efeitos, mas também porque é possível recuperar informações a partir das suas medidas para inferir propriedades importantes de fatores externos. Desta forma, o impacto dos efeitos externos sobre o gradiente de potencial foram estudados para Lisboa desde 1955 a 1991. As medições foram feitas usando um electrómetro Benndorf na estação meteorológica de Portela (nos subúrbios de Lisboa e perto do Aeroporto de Lisboa). Como Lisboa é uma cidade histórica, muito povoada e perto do mar, que fornece um conjunto de efeitos externos, como a poluição, que podem e devem ser estudados com recurso a mediadas de gradiente de potencial. O estudo elaborado contempla o efeito da poluição antropogénica como um efeito local no gradiente de potencial e a confirmação de um ciclo semanal persistente, devido à poluição urbana. Este estudo foi complementado com uma análise da dependência da direção do vento. Um segundo estudo foi feito sobre o efeito da humidade relativa sobre o gradiente de potencial. Uma formulação foi desenvolvida para relacionar propriedades microfísicas dos aerossóis, principalmente o parâmetro de higroscospicidade, com a medida macrofísica que é o gradiente de potencial. Resultados razoáveis foram obtidos entre o modelo e os dados experimentais, indicando a presença de uma fracção de aerossóis higroscópicos. Um terceiro estudo foi baseado num evento particular, o incêndio do Chiado, que teve lugar no dia 25 de agosto de 1986 e é considerado o acidente mais trágico que ocorreu em Lisboa desde o terramoto de 1755. O efeito da pluma de fumo sobre o gradiente de potencial, assim como o transporte da pluma desde área do Chiado até à Portela foram estudados. Foi observado pela primeira vez que o fumo do incêndio foi responsável por um aumento de gradiente de potencial significativo com uma baixa probabilidade de ocorrer por acaso. Este estudo pode incentivar o uso de medições gradiente de potencial em detectores de rede de incêndios. Finalmente, foram realizadas simulações sobre o Circuito Global Elétrico (circuito primário) e seu acoplamento para medições locais (circuito secundário). O objectivo foi o de separar os efeitos globais dos efeitos locais gerados pela poluição sobre a resistência colunar na superfície da Terra onde as medições são realizadas; Abstract: Present knowledge tells us that Earth’s atmosphere itself represents a global electrical circuit, which provides a continuous electrified atmosphere. The study of this global circuit as well as the effects, globally and locally wise, on the vertical component of the atmospheric electrical field, usually referred as Potential Gradient, are of great importance not only because of the dynamical response of the Potential Gradient to those effects, but also because it is possible to retrieve information from its measurements to infer the proprieties of important external factors. In this way, the impact of external effects on the Potential Gradient was studied for Lisbon from 1955 to 1991. The measurements were done using a Benndorf Electrograph at the Portela meteorological station (in the suburbs of Lisbon and near the Lisbon Airport). Since Lisbon is an historical city, very populated and near sea, it provides a set of external effects, like pollution, which can and should be studied through measurements of Potential Gradient. The core study done contemplates the effect of anthropogenic pollution as a local effect on the Potential Gradient and the confirmation of a persistent weekly cycle, due to urban pollution. This study was complemented with a wind direction dependence analysis. A second study was made regarding the effect of relative humidity on the Potential Gradient. A formulation was developed to relate microphysical proprieties of the aerosols, mainly the hygroscopicity parameter, with the macrophysical measure of Potential Gradient. Reasonable fits were obtained between the model and the experimental data indicating the presence of a small fraction of hygroscopic aerosols. A third study was based on a particularly event, the Chiado’s fire that took place on 25th of August 1989 and is considered the most significant hazard which occurred in Lisbon since the 1755 earthquake. The effect of the smoke plume on the Potential Gradient, but also how the plume travelled from the Chiado area to Portela was studied. It was observed (for the first time) that the fire smoke was responsible for a significant Potential Gradient increase with a low probability to occur by chance. This study might encourage the use of Potential Gradient measurements in fire network detectors. Finally, simulations regarding the Global Electrical Circuit (primary circuit) and its coupling to local measurements (secondary circuit) were performed. The objective was to separate the global effects from the local effects generated by pollution on the columnar resistance at Earth surface where measurements are made.

Thesis (S.M. in Geosystems)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998.
Includes bibliographical references (leaves 62-64).
by Youshun Sun.
S.M.in Geosystems

The nature of a biomaterial surface will influence interactions that will occur thereon. specifically, the chemical composition and topography will dictate the availability of sites of reactivity thereby determining the interfacial response. At the biological level, it is this surface mediated response that indicates the biocompatibility of the material. Hence, understanding and controlling the causative elements of the interfacial response will allow for the engineering of specific cell-biomaterial interactions.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.
Page 177 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (pages 171-176).
This doctoral thesis focuses on the application of geodetic techniques and finite element modeling to studying crustal deformation and other processes. In particular, it focuses on optimizing standard processing strategies, reducing the noise in the measurements and mitigating the effects of external processes in order to extract the signal of interest. Geodetic techniques, such GPS and InSAR, are still affected by major sources of errors, such as multipath, atmospheric effects, snow, blockage of the signal by infrastructure that can make difficult the detection of geophysical signal. In this thesis, I analyze three sets of data for which I have used different approaches to estimate the displacement and to investigate the sources of deformation that contribute to the signal. The first project consists of studying the deformation caused by the seasonal cycle of injection/withdrawal of gas in a depleted gas reservoir using InSAR measurements and Finite Element modeling techniques. In this project, I present a method to reduce the atmospheric signal, using statistical techniques and filtering and to estimate the error on the measurements. I compare the estimates with Finite Element modeling of the reservoir, using an elastic rheology. The second project analyses the unrest of Katla volcano in Iceland using GPS observables. GPS stations on top of the volcano register a complex signal, caused by the concurrence of different processes, such as snow on the antenna, multipath, earthquakes, volcanic deformation and hydrological events. In this project, I explore methods to detect the effects of snow/ice on top of antennas and to separate the different sources of the signal in order to extract the volcanic deformation component. I then compare the GPS measurements with a finite element model of snow/ice load on the volcano to validate the source of the estimated deformation. The third project involves the analysis of long term deformation and determination of vibrations of the Al-Hamra tower in Kuwait, using 24-hours averaged, 6-hours averaged and 1 Hz GPS measurements. The signals of GPS stations mounted on buildings are often affected by multipath due to reflective objects on the roof and suffer from reduced accuracy due to the partial masking of the sky by infrastructures on the roof. I explore different ways to mitigate the multipath, assessing an optimal GPS processing strategy for building installation. As the resulting deformation observed by the GPS instruments is highly correlated to variations in temperature, I present a finite element model of the building, where the major source of deformation is caused by a differential heating of the external walls. I also discuss the effects of the winds on the structure of the building, analyzing the high rate GPS measurements.
by Martina Coccia.
Ph. D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1987.
Microfiche copy available in Archives and Science.
Bibliography: leaves 71-75.
by Marc H. Larrère.
M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, February 2008.
Includes bibliographical references (p. 133-151).
Carbonaceous aerosols are among the most prevalent yet least understood constituents of the atmosphere, particularly in urban environments. We have performed analyses of field samples and laboratory studies to probe the physico-chemical properties of soot and organic aerosols in a complimentary approach to obtain information essential for understanding their atmospheric evolution and environmental effects. Samples of particulate matter < 2.5 pm in diameter (PM2.5) were collected from the Mexico City Metropolitan Area (MCMA) for both bulk compositional analysis and single particle characterization. Approximately 50% of the non-volatile component of PM2.5 was found to consist of carbonaceous material, including both soot and organics. Other major components included sulfates, soil/dust and heavy metals indicative of industrial emissions. Single particle analysis confirmed the prevalence of soot particles; our evidence suggests they quickly became internally mixed with sulfates and other inorganic compounds in a day or less through extensive processing during their atmospheric residence times. In the second half of our approach, a Quartz Crystal Microbalance - Chemical Ionization Mass Spectrometry (QCM-CIMS) system was developed to probe the OH-initiated oxidation of organic and soot thin films as atmospheric aerosol surrogates. Mass loss (volatilization) from the films was observed upon exposure to OH radicals in the presence of 02 at 295 K and 100 Torr. The loss rate was found to be linearly dependent on OH and independent of 02 concentrations over the range 02 _1012 to 2.1018 molec/cm3. A relatively slower mass loss rate in the presence of NOx suggests simultaneous formation of alkyl nitrate compounds potentially important in polluted urban environments. Experimental data were used to extract the rate constants of individual steps within the context of a previously proposed oxidation mechanism.
Volatilization was observed in 15% relative humidity at a rate slower than under dry conditions, suggesting water adsorption to the surface. Initially hydrophobic alkane surfaces became noticeably hydrophilic as a result of oxidation. Although the oxidized surfaces did not exhibit measurable water uptake, water contact angle measurements show increased hydrophilicity, suggesting formation of polar (oxygen-containing) organic functional groups.
by Kirsten S. Johnson.
Ph.D.

A statistical approach is used to correct dynamical forecasts of seasonal-mean temperatures at the earth's surface (SAT) and at 850 hPa (T850) from a global dynamical model (GCM3). In essence, the approach aims to correct systematic errors in the model's response to the two main patterns of sea surface (SST) anomalies in the tropical Pacific. The SAT (or T850) anomalies that are considered are therefore those related to the tropical Pacific sea surface temperature SST anomalies, as revealed by a Singular Value Decomposition (SVD) analysis. The post-processing method is applied to mean winter forecasts made available by the Historical Forecasting Project for 30 winters (1969 to 1998). We have verified whether the statistical method improves the predictions of the SAT (or T850) patterns associated with the Southern Oscillation Index (SOI), i.e., the El-Niño Southern Oscillation, and the North Atlantic Oscillation (NAO) index. The results show that the method substantially improves the predicted SAT (T850) patterns associated with the NAO. As for the SAT (or T850) pattern associated with the SOI, there is no improvement in the forecasts, likely due to the fact that the original, uncorrected predictions are already quite good. We also examine how the above post-processing translates into actual forecast skill scores, i.e., when all the variability in the observations is considered, as opposed to only the variability linked to the SOI and NAO. We examine the regions where the post-processing has a significant impact on the ensemble forecasts and the possible reasons it is either improving or deteriorating the skill scores.
Une approche statistique est utilisée dans le but de corriger des ensembles de prévisions saisonnières de la température de l'air à la surface (SAT) et à 850 hPa (T850) à partir d'un modèle dynamique global (GCM3). Le but de l'approche est de corriger des erreurs systématiques associées à la réponse du modèle aux deux principaux patrons reliés à la réponse de la température à la surface de l'océan (TSO) dans le Pacifique tropical. Les anomalies de la SAT (ou T850) reliées aux anomalies de la TSO sur le Pacifique tropical peuvent être obtenues à partir d'une analyse de décomposition des valeurs singulières (SVD). La méthode de post-traitement est appliquée aux moyennes d'ensemble de prévisions pour l'hiver. Ces ensembles de prévisions ont été fournis par le "Historical Forecasting Project" pour 30 hivers (1969 à 1998). Nous avons vérifié si la méthode statistique améliore les prévisions des patrons de la SAT (ou T850) associés à l'indice de l'oscillation du sud (SOI) ou à l'indice de l'Oscillation Atlantique Nord (NAO). Les résultats montrent que la méthode améliore les prévisions des patrons du SAT (ou T850) associés à l'indexe NAO. Par contre, les patrons du SAT (ou T850 ) associés au SOI, ne sont pas améliorés par le post-traitement statistique. Nous examinons aussi comment la méthode de post-traitement peut améliorer la qualité des prévisions “totale” i.e., quand toute la variabilité atmospherique est prise en compte, et non seulement celle associée aux indices SOI et NAO.

Lagrangian particle models are useful for modelling pollutants in the atmosphere. They simulate the spread of pollutants by modelling trajectories of individual particles. However, to be useful, these models require a density estimate. The standard method to use has been boxcounting, but kernel density estimator (KDE) is an alternative. How KDE is used varies as there is no standard implementation. Primarily, it is the choice of kernel and bandwidth estimator that determines the model. In this report I have implemented a KDE for FOI’s Lagrangian particle model LPELLO. The kernel I have used is a combination between a uniform and Gaussian kernel. Four different bandwidth estimators has been tested, where two are global and two are variable. The first variable bandwidth estimator is based on the age of released particles, and the second is based on the turbulence history of the particles. The methods have then been tested against boxcounting, which by using an exceedingly large number of particles can be seen as the true concentration. The tests indicate that KDE method generally performs better than boxcounting at low particle numbers. The variable bandwidth estimators also performed better than both global bandwidth estimators. To achive a firmer conclusion, more testing is needed. The results indicate that KDE in general, and variable bandwidth estimators in specific, are useful tools for concentration estimate.

Whilst the underlying mechanisms of atmospheric turbulence are complex, the observed effects on imaging can be described in simpler terms. In this thesis, I address the effects seen as geometric distortions in anisoplanatic imaging and propose new digital restorations techniques that are real-time capable and predictive. The anisoplanatic problem arises in wide-field telescopic imaging and in new ventures of astronomy such as giant telescopes that process wide-field imagery. The methods proposed here, both digital and digital-optical hybrid, remove the position dependent distortions as a precursor to image analysis. Previous existing digital restoration techniques have used a prototype formed by averaging an image time sequence for image registration where valuable high frequencies information is lost due to the low-pass filtering effect of averaging. The proposed techniques are capable of using any arbitrary frame in the sequence as prototype, thus circumventing the low pass filtering effect and also allowing real-time implementation. Furthermore, these techniques are made predictive by the use of Kalman filtering. The predictive capabilities of these techniques open a new path to the combination of digital processing and adaptive optics that can result in hybrid systems. The key to adoption of hybrid systems is to reduce the complexity and expense of the optics and couple this with digital processing prediction. To this end I also propose a new type of inexpensive and fast piezoelectric deformable mirror based on the vibration modes of circular PVDF membranes that exhibit striking similarities to Zernike polynomials. It requires only two electrodes for actuation and a very simple driving signal generator, therefore constituting an inexpensive and viable alternative to existing deformable mirrors. With the emergence of multi-conjugate adaptive optics (MCAO) and multiobject adaptive optics (MOAO) in astronomy, and the more demanding correction required for long range surveillance imaging, this inexpensive deformable mirror and the real-time capable digital algorithms are promising building blocks for a hybrid solution to the anisoplanatic imaging problem.

The turbulent atmosphere degrades images of objects viewed through it by introducing random amplitude and phase errors into the optical wavefront. Various methods have been devised to obtain true images of such objects, including the shift-and-add method, which is examined in detail in this work. It is shown theoretically that shift-and-add processing may preserve diffraction-limited information in the resulting image, both in the point source and extended object cases, and the probability of ghost peaks in the case of an object consisting of two point sources is discussed. Also, a convergence rate for the shift-and-add algorithm is established and simulation results are presented. The combination of shift-and-add processing and Wiener filtering is shown to provide excellent image restorations.

Solar radiometers, which are used for remote sensing of atmospheric aerosols and absorbing gases, have traditionally been calibrated by the Langley method. Temporally variable conditions, however, can significantly bias the zero-airmass intercepts obtained by this method. In this dissertation, a number of new signal processing techniques are developed to better characterize aerosol variability and use it to obtain improved intercepts under a broad range of conditions. The techniques include (1) an extension of Forgan's method, using correlation between optical depths at different wavelengths to model temporal variations; (2) spectral/fractal analysis and filtering to identify systematic atmospheric variations and distinguish them from noise; and (3) error correction using correlation between results from different data sets. These techniques, along with some preliminary adjustments and an algorithm for estimating ozone content, are incorporated into an iterative processing scheme that both calibrates the instrument and provides improved estimates of each optically significant atmospheric constituent. Finally, the characterization of aerosol variability is further enhanced by analyzing data taken with a customized radiometer that measures diffuse skylight as well as direct sunlight.

Hyperspectral data is a powerful tool for mineral explorations and lithological discriminations. EO1-Hyperion is a space borne hyperspectral system for hyperspectral imaging which is capable of 220 spectral image channels within the range of 400 to 2500 nm wavelengths. It has advantages over airborne systems such as data cost and coverage area. Although it has many advantages, much more uncertainty exists in application period, of which this uncertainty does exist in all processing stages starting from the data preparation to the end of analysis stages. The aim of this thesis is to state the potential use of Hyperion data for lithological and mineralogical discriminations to further develop new hyperspectral image processing approach, and to improve existing preprocessing method in literature. The proposed algorithm is mainly based on atmospheric corrections and cross track illumination correction of Hyperion data. In order to achieve this, two test sites were selected. Site 1 located on the Central Anatolia, (Ekecek test site) is used for lithological discrimination and Site 2 located on West Anatolia (Biga test site) is used for mineralogical discrimination. The obtained results were compared and assessed with the field verifications, spectral measurements and existing spectral libraries. In the end of the study it is found that when proposed approach is followed hyperspectral data is proven to be a useful tool for mineralogical discrimination in mono minerallic outcrops and valuable for lithological mapping in relatively homogenous un-covered outcrops.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 201-204).
As humankind expands its footprint in the solar system, it is increasingly important to make use of Earth independent resources to make these missions sustainable and economically feasible. In-Situ Resource Utilization (ISRU), the science of using space resources to support exploration missions, unlocks potential destinations by significantly reducing the mass to be launched from Earth. Mars is considered a promising location with significant indigenous resources. The carbon dioxide that comprises nearly 96% of the Martian atmosphere can be utilized to produce oxygen for propulsion and life support systems. The Mars Oxygen ISRU Experiment (MOXIE) is a payload being developed by NASA for the Mars 2020 mission. MOXIE will demonstrate oxygen production at a rate of at least 6 grams per hour from the Martian atmosphere by using solid oxide electrolysis (SOXE) technology. Individual SOXE cells form a 10-cell SOXE stack. The stack consists of two 5-cell groups to generate oxygen and carbon monoxide molecules from a CO₂ electrolysis reaction. MOXIE is the first step to creating an oxygen processing plant that might enable a human expedition to Mars in the 2030s through the production of the oxygen needed for the propellant for a Mars Ascent Vehicle (MAV). MOXIE will be the first demonstration of ISRU on another planet. The goal of this program is to learn what technological advancements are needed for development of larger scale ISRU systems to support human spaceflight missions. This thesis studies solid oxide electrolysis based atmospheric ISRU systems from a controls and system performance perspective. The purpose is to use the results of this analysis to inform MOXIE operation and the design of a full-scale ISRU system for Mars. A novel, tunable grey electrochemical model is developed from experimental characterization and used to predict oxygen production and safe operational limits for MOXIE. This model is then incorporated into the first multi-domain physical system model of a solid oxide electrolysis system implemented in Simscape. This model, named SimSitu, is used to test MOXIE control interactions and performance. A new control system, The Safe Margin Active Reduction Tracking (SMART) controller is proposed to safely maximize oxygen production from MOXIE. A strategy for characterizing and selecting space flight SOXE stacks based on discoveries from experimental results is also proposed. The models and lessons learned from MOXIE are then applied to make scaling estimates and recommendations for a full-scale ISRU system.
by Forrest Edward Meyen.
Ph. D.

The approach advocated in this work implements energy/exergy analysis and indirectly an irreversibility evaluation to a continuous manufacturing process involving discrete net shape production of compact heat exchangers through a complex controlled atmosphere brazing (CAB) process. The system under consideration involves fifteen cells of a continuous ramp-up heating, melting, reactive flow, isothermal dwell, and rapid quench solidification processing sequence during a controlled atmosphere brazing of aluminum compact heat exchangers. Detailed mass, energy, and exergy balances were performed. The irreversibility sources were identified and the quality of energy utilization at different processing steps determined. It is demonstrated that advanced thermodynamics metrics based on entropy generation may indicate the level of sustainable energy utilization of transient open systems, such as in manufacturing. This indicator may be related to particular property uniformity during materials processing. In such a case, the property uniformity would indicate systems distance from equilibrium, i.e., from the process sustainable energy utilization level. This idea is applied to net shape manufacturing process considered. A metric based on exergy destruction is devised to relate the heat exchanger temperature uniformity and the quality. The idea advocated in this thesis will represent the coherent framework for developing energy efficient, economically affordable and environmentally friendly manufacturing technology.

Laboratory based temperature-dependent kinetics and product yields for alkene ozonolysis and the reaction of CH3O2 with ClO and BrO have been measured via chamber studies and a turbulent flow tube coupled to CIMS (Chemical Ionisation Mass Spectrometry). In order to gain a better understanding of the fate of the products formed during hydrocarbon oxidation and their subsequent impact on the ozone budget (and so the oxidising capacity of the atmosphere) it is imperative to know the rate at which these reactions proceed and to identify their product yields. As tropospheric temperature varies, Arrhenius parameters were determined during the ozonolysis of selected alkenes. The temperature dependent kinetic database was extended and the activation energies for the ozonolysis of selected alkenes were correlated with an existing SAR (Structure Activity Relationship). Given the myriad organic species in the atmosphere, SARs are useful tools for the prediction of rate coefficients. Inclusion of Arrhenius parameters into the SAR allows for prediction over a range of temperatures, improving the conditions reflected in models. Achieving mass balance for alkene ozonolysis has proven to be a difficult challenge considering the numerous pathways of the Criegee Intermediate (CI). The product yield of formic acid – an organic acid with significant atmospheric implications which is under predicted by models – was determined as a function of relative humidity during ethene ozonolysis. This reaction exhibited a strong water dependence which lead to the prediction of the reaction rate of the CI with water which ranges between 1 × 10-12 – 1 × 10-15 cm3 molecule-1 s-1 and will therefore dominate its loss with respect to bimolecular processes in the atmosphere. Peroxy radicals, strongly influence the total oxidising capacity of the troposphere. The reaction of peroxy radicals with halogen oxides is recognised to be responsible for considerable ozone depletion in the atmosphere, exacerbated by reactive halogens (X, XO) taking part in catalytic cycles. Arrhenius parameters were determined for ClO + CH3O2 and BrO + CH3O2. Temperature is an important parameter affecting rate, exemplified here as the reaction involving ClO exhibited a positive temperature dependence whereas for BrO a negative temperature dependence was evident. As a consequence, the impact of ClO + CH3O2 with respect to ozone loss is diminished. Global modelling predicts a reduction in ozone loss by a factor of around 1.5 and implicates regions such as clean marine environments rather than the polar stratosphere. Conversely, a more pronounced temperature dependence for the reaction of BrO with CH3O2 placed particular importance on lower stratospheric chemistry where the modelled CH3O2 oxidation is doubled. The main products for this reaction were identified to be HOBr and CH2O2. The decomposition of CH2O2 could enhance HOx in the lower and middle stratosphere and contribute to a significant source of HOx in the upper troposphere. Bimolecular reaction of CH2O2 with water could also provide a none negligible source HC(O)OH in the upper troposphere. Alkenes and peroxy radicals undergo chemical processing in the atmosphere whilst acting as a source and sink of ozone and thus can impose detrimental effects on the biosphere, climate and air quality of the Earth.

The atmosphere is a heterogeneous system which is rich in potential chemistry. The processes taking place within this system as well as at the interface of its constituents are of immense importance in understanding how the atmosphere in turn can impact the well-being of all living on the surface of earth. Thus, the heterogeneous chemistry of atmospheric aerosols has since long been subjected to extensive scientific investigation, in view of broadening our understanding of this imperative system. In this study, the heterogeneous interactions of water vapor and gaseous HNO3 on goethite (a-FeOOH), a prominent component of mineral dust aerosol is investigated with quartz crystal microbalance (QCM) measurements and attenuated total reflectance - Fourier transform IR (ATR-FTIR) spectroscopy. Laboratory synthesized goethite samples of varying size (microrods of specific surface area 34 m2/g and nanorods of specific surface area 121 m2/g) were used in order to identify the size dependent interaction of goethite with H2O and HNO3. The study revealed that the exposure of goethite to gas phase H2O and HNO3 results in the uptake of these gases via surface adsorption. Additionally, this novel combined approach of QCM and ATR-FTIR spectroscopy allowed for quantification of the amount of uptake while the spectroscopic data provided information on the speciation of adsorbed products. Thus, with the QCM and spectroscopic data in hand, a precise interpretation of the reactivity as well as its size dependence was sought. In a general sense, the reactivity of a substance is believed to increase with decreasing particle size. The results of this investigation show that in the case of H2O, both microrods and nanorods take up water while the total amount of adsorbed water, when normalized to surface area, is similar for both particle sizes. However, for HNO3, the saturation coverage of total and irreversibly bound HNO3 on microrods was observed to be higher than that on nanorods. With supplementary analysis, this anomalous size effect was attributed to structural features such as the involvement of surface hydroxyl groups in determining the reactivity, which would be subjected to change as a function of particle size. Furthermore, an investigation of the behavior of HNO3 reacted goethite in aqueous media and the uptake of H2O and HNO3 at their mutual presence was carried out such as to better understand the effects of atmospheric processing upon dispersal within the hydrosphere. Further analysis is warranted before arriving at a general conclusion on the size-dependent reactivity of goethite. However, we may argue that goethite containing aerosols may indicate the same pattern of reactivity within the atmosphere as that observed here. Thus, the inference of this investigation proves to be significant in broadening our understanding of this atmosphere as well as the entire biosphere as a whole.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The useless tire is a residue that must be managed correctly until its final disposal as well as its collection and storage must be done adequately. Therefore, if it is inadequately disposed of, it can cause damages to the environment and to public health. In March 2005 the city of João Pessoa, initiated a program called Programa Nordeste Rodando Limpo - Northeastern Program of Clean Twirling - through the partnership between private companies, which consisted of the collection and final destination of the useless tires to be used in the ovens to produce clinker, providing a market value to these residues. This research was developed at CIMPOR, a cement plant located in the city of João Pessoa and has as its objective to make an analysis of the main benefits of the use of theses tires during the co-processing step inside the clinker oven. The methodology applied in this study were based on the qualitative evaluation of the generated benefits to public health and the quantitative social profits generated to the recycling workers and identifying profits with the collection of the tires as well as the increasing of the these workers income. The same research also verified that the co-processing atmospheric emissions and CO2 emissions were prevented during the transportation of the Petroleum coke. This also lessened the involved costs with this process. In all cases, the final results had confirmed the existence of environmental and social benefits in the use of the co-processing system, making possible the withdrawal of 26.568, 90 tons of useless tires that were deposited in the State of Paraiba. Consequently, in neighboring states, it was also verified the automatic creation of a mechanism of collection by the society that made possible economic profits of an estimated R$ 2 million reais to the recycling workers improving their quality of life. Another important data observed in the same study was a gradual increase of the use of useless tires, implying in a lesser consumption of non renewable fuel and the minimization of atmospheric emissions which prevents high levels of CO2 emissions, generally caused by the lesser volume of Petroleum coke produced, also resulting, in the decrease of the production costs.
O pneu inservível é um resíduo que deve ser gerido corretamente até sua disposição final e, deve ser coletado e armazenado adequadamente, pois quando disposto inadequadamente tanto pode causar danos ao meio ambiente quanto à saúde pública. Em João Pessoa foi iniciado, em março de 2005, o Programa Nordeste Rodando Limpo através da parceria entre empresas privadas, que consiste na realização de coleta e destinação final dos pneus inservíveis para utilização nos fornos de fabricação de clínquer, fazendo com que estes passem a ter valor no mercado de resíduos. O estudo foi desenvolvido na Fábrica da CIMPOR localizada na cidade de João Pessoa e tem por objetivo fazer uma análise sobre os principais benefícios da utilização de pneus inservíveis no coprocessamento no forno de clínquer. A metodologia utilizada foi baseada na avaliação qualitativa dos benefícios gerados a saúde pública e quantitativa dos ganhos sociais gerados aos catadores, identificando ganhos com a coleta dos pneus, mensurando o aumento da renda dos mesmos. O referido trabalho também verificou as emissões atmosféricas do coprocessamento e as emissões evitadas de CO2 no transporte do coque de petróleo, além da economia de custos envolvidos com o coprocessamento. Os resultados obtidos confirmaram os benefícios ambientais e sociais no coprocessamento, sendo possível a retirada de 26.568,90 toneladas de pneus inservíveis que estavam depositados no estado da Paraíba e em estados vizinhos, além da criação automática de um mecanismo de coleta pela sociedade, que possibilitou ganhos econômicos da ordem de R$ 2 milhões de reais aos catadores, melhorando assim, sua qualidade de vida. Verificou-se também um gradativo aumento da utilização de pneus inservíveis, implicando em um menor consumo de combustíveis não-renováveis, minimizando emissões atmosféricas e evitando níveis de emissões de CO2, devido ao menor volume de coque transportado, resultando também, na minimização dos custos de produção.

Temperaturprognoser är av stor betydelse för många i dagens samhälle, både privatpersoner och diverse olika sektorer. Förväntan på att prognoserna håller hög träffsäkerhet är stor och god kvalitet på dessa är viktigt av många olika aspekter. De numeriska vädermodellerna, som används för att göra väderprognoser, har brister som i stort sätt alltid leder till systematiska fel i prognoserna. Bristerna beror exempelvis på dålig representation av atmosfärens fysikaliska processer och för att korrigera och reducera dessa fel efterbehandlas prognoserna med olika metoder, så kallad post-processing. För att minimera de systematiska felen och öka träffsäkerheten för prognoserna pågår ständigt en utveckling och förbättring av både modellerna och post-processingmetodiken. Uppföljning och utvärdering av prognoser är av stor nytta för denna utveckling som ska leda till minimering av prognosfel och optimering av modell och metodik. I denna studie har temperaturprognosdata, med prognoslängd 0-12 timmar, från Sveriges Meteorologiska och Hydrologiska Institut (SMHI) och norska Meteorologisk institutt (met.no) jämförts med uppmätta värden för 2 m-temperatur. Observerad temperaturdata från 22 olika synoptiska väderstationer på platser utspridda över hela Sverige har använts i studien och perioden som studien är baserad på är 20 februari till 31 maj 2018. Statistiska mått, med mest fokus på korrelationskoefficient och bias, har analyserats och jämförts för att undersöka likheter och skillnader i temperaturprognoserna från de två olika väderinstituten. Resultaten av studien visar att temperaturprognoserna från met.no generellt sett har något högre träffsäkerhet än SMHI:s för de allra flesta av de 22 geografiska platserna. Båda institutens prognoser har för flertalet av stationerna i fjällen samt norra Sverige generellt sett lägre träffsäkerhet för februari än för mars, april och maj.
Temperature forecasts are of great importance for many different reasons in today's society, both for private individuals and various sectors. The expectations that the forecasts maintain high accuracy and good quality is important in many different aspects. The weather models, which are used to make the forecasts, have deficiencies which in large part always lead to systematic errors in the forecasts. The deficiencies are for example, due to poor representation of the physical processes of the atmosphere and to correct and reduce these errors, the forecasts are post-processed by various methods. To minimize the systematic errors and increase the accuracy of the forecasts, there is an ongoing development and improvement of both the models and the post-processing methods. Evaluation of forecasts is of great benefit to this development, which will lead to minimization of forecast errors and optimization of the model and methodology. In this study, temperature forecast data, with a forecast length of 0-12 hours, from the Swedish Meteorological and Hydrological Institute (SMHI) and the Norwegian Meteorological Institute (met.no) were compared with measured 2 m-temperature values. Observed temperature data from 22 different weather stations in locations scattered all over Sweden have been used in the study and the period on which the study is based is from the 20th of February to 31st of May, 2018. Different statistical measures have been analyzed and compared to examine similarities and differences in temperature forecasts from the two different weather institutes. The results of the study show that met.no's temperature forecasts generally have slightly higher accuracy than SMHI's for most of the 22 locations. For any of the stations in the mountains and northern Sweden forecasts from both institutes generally have lower accuracy for February than March, April and May.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Recent studies have proved the positive effect of atmospheric plasma in a range of inactivating microorganisms and spores; however, less attention has been given to the emerging technology of this impact on the physico-chemical, nutritional and functional food. In this context, the present study investigated the effects of processing by atmospheric plasma on the quality characteristics in grape juice. Therefore, grape juice, obtained by centrifugation of the cultivar "Isabel" was exposed for 0 (control), 1, 2, 4, 6 minutes to a cold atmospheric plasma jet. Plasma was generated in helium gas by applying a dielectric barrier discharge (DBD) to a voltage 90kV, frequency of 10KHz and a gas flow of 2l/min. The physico-chemical characteristics (pH, soluble solids, titratable acidity, color, reducing sugars, phenolics and anthocyanins, antioxidant potential) and microbiological (Escherichia coli, coliforms, mesophilic aerobic, yeasts and molds) were compared before and after processing. The results indicate that under the experimental conditions used, the processing by atmospheric plasma remained the same physico-chemical characteristics of fresh grapefruit juice. Furthermore, after six minutes of treatment, a significant difference was found in bioactive compounds, at a magnification at a concentration of phenolics and antioxidant activity anthocyanins. Regarding the microbiological quality, no colony forming unit for mesophilic aerobic, molds and yeasts was observed after two minutes of treatment. However, despite the encouraging results, further investigation needs to be conducted in order to detail the food processed behavior during their lifetime.
Recentes estudos tem demonstrado o efeito positivo do plasma atmosférico na inativação de uma gama de microrganismos e esporos; no entanto, menos atenção tem sido dada ao impacto desta tecnologia emergente sobre as características físico-químicas, nutricionais e funcionais dos alimentos. Neste contexto, o presente estudo investiga os efeitos do processamento por plasma atmosférico sobre as características de qualidade em suco de uva integral. Para tanto, o suco de uva, obtido por meio de centrifugação da cultivar “Isabel”, foi exposto por 0 (controle), 1, 2, 4, 6 minutos a um jato de plasma à pressão atmosférica. O plasma foi gerado em gás hélio, mediante a aplicação de uma descarga de barreira dielétrica (DBD) a uma voltagem de 90kV, frequência de 10KHz e um fluxo de gás de 2l/min. As características físico-químicas (pH, sólidos solúveis, acidez titulável, cor, açúcares redutores, fenólicos e antocianinas totais, potencial antioxidante) e microbiológicas (Escherichia coli, Coliformes, mesófilos aeróbios, leveduras e bolores) foram confrontadas antes e após o processamento. Os resultados indicam que, dentro das condições experimentais utilizadas, o processamento por plasma atmosférico manteve as mesmas características físico-químicas do suco de uva fresco. Além disso, após seis minutos de tratamento, uma diferença significativa foi encontrada em compostos bioativos, com uma ampliação na concentração de fenólicos, antocianinas e potencial antioxidante. Em relação a qualidade microbiológica, nenhuma unidade formadora de colônia para Escherichia coli, coliformes, mesófilos aeróbios, bolores e leveduras foi observada após dois minutos de tratamento. Contudo, apesar dos resultados encorajadores, investigações mais aprofundadas precisam ser realizadas com o objetivo de detalhar o comportamento do alimento processado durante o seu tempo de vida útil.

Este trabalho teve como objetivo avaliar o impacto radiológico atmosférico da Unidade de Concentrado de Urânio URA, Caetité, BA, através da modelagem da dispersão de radionuclídeos e a estimativa da dose efetiva anual (em mSv.ano-1). Para tal, utilizou-se o programa MILDOS-AREA que foi desenvolvido pelo Argonne National Laboratory (ANL) em conjunto com a U.S. Nuclear Regulatory Commission (USNRC), para avaliar impacto radiológico ambiental atmosférico nas instalações de mineração e beneficiamento de urânio. O incremento de dose efetiva anual para três grupos críticos hipotéticos e oito grupos populacionais reais foi estimado com base na medida de fluxos de radônio e na estimativa das concentrações de radionuclídeos em particulados no ar dos principais termos fontes da URA (cava da mina, depósito de estéril e britador). Paralelamente, as medidas de concentração de radônio e taxa de kerma no ar, reportadas nos relatórios dos programas de monitoração ambiental pré-operacional (PMAPO) e operacional (PMAO) da URA, foram avaliadas. Os valores de dose efetiva anual estimados para os grupos críticos hipotéticos variaram de 1,78E-02 a 2,10E-02 mSv.ano-1, enquanto que para os grupos populacionais, variaram de 7,49E-05 a 1,56E-02 mSv.ano-1. A maior contribuição para o incremento da dose foi devida a inalação do radônio, sendo responsável por quase a totalidade da dose efetiva anual estimada. A média da concentração de atividade de radônio no entorno da URA foi 137,21 Bq m-3 e não sendo observada diferenças significativas entre as concentrações de radônio reportadas nos programas de monitoramento ambiental pré-operacional (valores de background) e operacional. Os valores médios de taxa de kerma no ar no entorno da URA foram de 0,136 μGy h-1. No entanto, em todos os pontos de monitoramento, os valores reportados no programa operacional foram inferiores aos valores reportados no programa pré-operacional (background), o que sugere problemas de medidas ou de coleta de dados durante a realização deste programa. O operador da URA utilizou para avaliação de impacto radiológico atmosférico, resultados apresentados em seus relatórios finais de análise de segurança (RFAS), um modelo próprio de simulação de dispersão, denominado Impacto Ambiental Radiológico (IAR7). Uma comparação entre o MILDOS-AREA e o IAR7, utilizando os mesmos parâmetros de entrada reportados no RFAS sugere que o IAR7 subestimou as concentrações de radônio no ar para os grupos críticos hipotéticos. Os resultados de simulação com o MILDOS-AREA mostram que as doses efetivas estimadas para os grupos críticos hipotéticos são inferiores a 0,3 mSv.ano-1 que é a restrição de dose estabelecida pela Comissão Nacional de Energia Nuclear. Recomenda-se que o código MILDOS-AREA seja utilizado no Brasil, para fins de licenciamento e controle, tendo em vista que o mesmo é um código validado e já utilizado em outros países para avaliar impacto radiológico ambiental atmosférico em instalações de mineração e beneficiamento de urânio
This work aimed to evaluate the atmospheric radiological impact of the Uranium Concentration Unit - URA, Caetité, BA, by modeling the dispersion of radionuclides and estimating the annual effective dose (in mSv.year-1). For this purpose, we used the MILDOS-AREA program that was developed by Argonne National Laboratory (ANL) jointly with the US Nuclear Regulatory Commission (USNRC) specifically to evaluate the atmospheric radiological impact of uranium mining and processing facilities. Taking into account estimative of particulate radionuclide concentration and radon flux measurements performed in the main source-terms of URA (open pit, heap leaching and tailing deposit), we estimated the increase of annual effective dose for three hypothetical critical groups and eight population groups. In addition, we evaluated results of radon activity concentration and kerma rate concentration in air reported in the pre-operational environmental monitoring program (PMAPO) and in the operational environmental monitoring programs (PMAO) from URA. The estimated annual effective dose to the hypothetical critical groups ranged from 1,78E-02 a 2,10E-02 mSv.year-1. For real populations, effective doses ranged from 7,49E-05 to 1,56E-02 mSv.year-1. The largest contribution to the total dose was due to inhalation of radon, accounting for almost the entire estimated annual effective dose. The average radon activity concentration in the vicinity of the URA was 137.21 Bq m-3 and there was no apparent difference between the radon concentrations reported in the pre-operational environmental monitoring program (background values) and post-operational. The average values of kerma rate in air surrounding the URA were 0.136 μGy h-1. However, for all the monitoring points, the values reported in operational environmental monitoring program were lower than the values reported in pre-operational environmental monitoring program (background), suggesting measurements or data collection problems during the pre-operational program. The miner industry used in their final report of safety analysis (RFAS), a proper dispersion model simulation, called Environmental Impact Radiological (IAR7). A comparison between the MILDOS-AREA and the IAR7 using the same input parameters in IAR7 suggested that IAR7 underestimated the radon concentrations in the air to the hypothetical critical groups. In conclusion, MILDOS-AREA simulation showed that the estimated effective doses for the hypothetical critical groups are less than 0.3 mSv.year-1, which is the operational dose limit to the public established by the National Nuclear Energy Commission. It is recommended that the MILDOS-AREA code should be used in Brazil, considering that it is a validated code and already used in other countries to assess atmospheric radiological impact on mining and uranium processing facilities

OPERA (Oscillation Project with Emulsion-tRacking Apparatus) est une expérience sur faisceau de neutrino située dans le Hall C du laboratoire souterrain du Gran Sasso (LNGS), en Italie, à une profondeur équivalente à 3.8 km d'eau (correspondant à une coupure en énergie à 1.5 TeV pour les muons à la surface). L'objectif premier d'OPERA est l'observation directe de l'oscillation νμ ➝ ντ dans le secteur des neutrinos atmosphériques par apparition d'événements ντ à 730km de la cible, dans un faisceau (CNGS) quasiment pur en νμ. OPERA est un détecteur hybride contenant une partie cible (~125 000 briques composées d'une succession de feuilles d'émulsion et de plomb) instrumentée et d'un spectromètre. La prise de données a commencé en 2006 et 55 000 événements neutrinos ont été enregistrés à ce jour. Le premier candidat ντ a été observé cette année. Le travail produit pendant cette thèse est axé suivant trois sujets principaux : la définition de règles de déclenchement du système d'acquisition du trajectographe pour les événements neutrinos du faisceau, la synchronisation des éléments du trajectographe et des plans de RPC ainsi que l'implémentation des résultats dans la simulation et l'étude de la faisabilité d'une analyse des oscillations des neutrinos atmosphériques dans les données hors-faisceau. La modification des règles de déclenchement du trajectographe a permis d'atteindre les valeurs proposées dans le proposal d'OPERA, ie une efficacité de déclenchement supérieure à 99%. Cette évolution a été rendu possible par la mise en place de fenêtres en temps en coïncidence avec le faisceau CNGS pendant lesquelles les coupures sont abaissées, permettant de récupérer les événements de basse multiplicité. Une étude poussée de l'intercalibration des détecteurs électroniques a permis la synchronisation de l'ensemble des informations venant des éléments du trajectographe et des RPC. Les résultats de cette analyse sont maintenant inclus dans la simulation du détecteur. Le travail de calibration a permis de produire une étude sur l'oscillation des neutrinos atmosphériques "hors-faisceau" grace à la détection de particules montantes. Les analyses présentées dans cette thèse ont permis une meilleure compréhension du détecteur d'OPERA et démontré sa capacité à observer des phénomènes ne dépendant pas du faiseau CNGS. Des analyses sur la détection des neutrinos atmosphériques et la caractérisation du flux de muons cosmiques (variations saisonnières entre autres) sont désormais possibles grace à la statistique accumulée et la compréhension plus fine des systèmes d'acquisition. Les corrections sur la propagation des signaux dans les détecteurs électroniques sont aujourd'hui utilisées pour la mesure de la vélocité des neutrinos du faisceau
OPERA (" Oscillation Project with Emulsion-tRacking Apparatus ") is a neutrino beam experiment located in hall C of the Gran Sasso underground laboratory (LNGS), in Italia, under a equivalent of 3.8 km water (corresponding to a cut at 1.5 TeV for the muons). The first purpose of OPERA is the direct observation of the νμ ➝ ντ oscillation in the atmospheric sector observing an ντ appearance 730 km away from the target in a quasi pure νμ beam (CNGS). OPERA is an hybrid detector with an instrumented target part (~125 000 bricks made with emulsion and lead sheets) and a spectrometer. The data taking have started in 2006 and 55 000 events have been registred. The first ντ candidate have been observed this year. The work done during this thesis is oriented around three main topics : Define the trigger rules of the target tracker acquisition system for beam neutrino events, synchronise target tracker and RPC elements, implement the results inside the simulation and the study of the feasibility of an atmospheric neutrino analysis using off-beam data. The new trigger rules succeeds to reach the values of OPERA proposal, ie a trigger efficiency greater than 99%. This improvement have been done thanks to coincidence time windows with the CNGS beam during which lower cut are applied, allowing low multiplicity events to be kept. A deep study of electronic detectors intercalibration makes possible the target tracker and RPC data synchronisation. The analysis results are now included in the official simulation. This calibration work have been then used for a study of " off-beam " atmospheric neutrino oscillation thanks to the selection of up-going particles. The analysis showed in the thesis have improved the OPERA detector understanding and demonstrate the feasability of an observation of phenomenoms independant from the CNGS beam. Analysis on atmospherics neutrino detection and muons flux caracterisation (seasonal variations for example) are now possible thanks to the accumulated statistics and the deeper understanding of the acquisition systems. Correction on signal propagation inside the electronic detectors are now used for a neutrino velocity measurement

Orientador: Benedito Carlos Benedetti
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: O morango é uma hortaliça de clima temperado e tem atração peculiar por sua coloração vermelha brilhante, odor característico, textura macia e sabor levemente acidificado. Dada à sua grande demanda para utilização na culinária nacional e internacional, é desejável o desenvolvimento de tecnologia para o seu processamento mínimo. O presente trabalho teve como objetivo avaliar a qualidade físico-química, sensorial e microbiológica de morangos processados minimamente e mantidos sob refrigeração e atmosfera controlada. Morangos da cultivar Oso Grande foram colhidos em campo de produção comercial, localizado no município de Pouso Alegre, MG, e transportados para o Laboratório de Pós-Colheita da Embrapa Agroindústria de Alimentos, localizada no município do Rio de Janeiro, RJ, sendo mantidos por aproximadamente 10 horas em câmara fria a 5ºC e 85% de umidade relativa, até o início do processamento. Após seleção e classificação, os frutos foram processados minimamente retirando-se o cálice e o pedúnculo dos frutos. A sanificação foi feita em água a 5ºC/10 minutos, com 150 µL L-1 de cloro ativo e o enxágüe em água a 5ºC/5 minutos, contendo 5 µL L-1 de cloro ativo. Depois de secos, os morangos foram pesados, acondicionados em bandejas plásticas do tipo polietileno tereftalato (PET) e mantidos sob atmosfera controlada durante 10 dias, a 5ºC e a 10ºC. O controle da atmosfera foi feito em microcâmaras e as seguintes composições atmosféricas foram estabelecidas: AC1 ¿ 3 % O2 + 10 % CO2 (balanço N2), AC2 ¿ 3 % O2 + 15 % CO2 (balanço N2), AA ¿ Atmosfera ambiente (controle). Os frutos foram avaliados nos dias 0, 3 e 7 e 10 quanto à perda de massa, firmeza, pH, acidez titulável, sólidos solúveis, açúcares (sacarose, frutose e glicose), teor de antocianinas totais, cor (valores L e a) e qualidade microbiológica. A análise sensorial foi realizada nos dias 3, 7 e 10 do armazenamento, com a avaliação dos atributos de aparência, textura e sabor. Não houve diferenças significativas entre as temperaturas de armazenamento 5ºC e 10ºC para a maioria das variáveis físico-químicas avaliadas. A atmosfera de armazenamento influenciou significativamente a perda de massa, a firmeza, o teor de frutose, de antocianinas totais. As atmosferas de armazenamento contendo 3% O2 + 10% CO2 e 3% O2 + 15% CO2 foram mais eficientes para a manutenção da firmeza dos frutos minimamente processados, bem como foram mais efetivas no controle da perda de massa que a atmosfera ambiente. Todavia, os frutos MP mantidos nestas atmosferas apresentaram menor teor de antocianinas que os mantidos em atmosfera ambiente, embora não se tenha observado mudanças significativas ao longo do período de armazenamento em nenhum dos tratamentos. A presença de sabores estranhos nos morangos processados minimamente e mantidos sob 3% O2 + 10% CO2 e 3% O2 + 15% CO2, quando avaliados sensorialmente, fez com que o produto fosse rejeitado pelos provadores a partir do 3º dia de armazenamento, quando a aparência ainda era adequada. A temperatura de 5ºC foi mais efetiva que a temperatura de 10ºC na manutenção da aparência, na retenção do sabor característico e na prevenção do surgimento de sabores estranhos. O tempo de armazenamento não afetou os atributos de textura e sabor avaliados sensorialmente, porém afetou todos os atributos de aparência, especialmente no 10º dia a 10ºC. A redução da temperatura de 10ºC para 5ºC e a utilização das atmosferas com 3% O2 + 10% CO2 e 3% O2 + 15% CO2 diminuiu o crescimento de bactérias psicrotróficas e de fungos filamentosos e leveduras, aumentando a vida útil dos morangos processados minimamente
Abstract: Strawberries are a temperate vegetable crop highly appreciated by consumers due to their unique characteristics such as bright red color, soft texture and slightly acidified flavor. Due to their high demand both at national and international level, the development of fresh-cut technology for strawberries is highly desirable. The present work was carried out aiming at evaluating physico-chemical, sensorial and microbiological characteristics of fresh-cut strawberries kept under refrigeration and controlled atmosphere. Strawberries 'Oso Grande¿ were harvested at a commercial field located at Pouso Alegre, MG, and transported to the Postharvest Laboratory at Embrapa Agroindústria de Alimentos, Rio de Janeiro, RJ, and were stored for approximatelly 10 hours in cold rooms at 5ºC and 85% relative humidity until processing. After grading and sizing fruits were minimally processed and the calyx and peduncle were removed. Sanitation was done in a solution of chlorine (150 µL L-1) at 5°C for 10 min. Rinsing was carried in a solution of chlorine of 5 µL L-1 at 5°C for 5 min. After room drying, fruits were weight, placed in plastic trays polyethylene tereftalato type (PET) and kept under controlled atmosphere conditions for 10 days at 5 and 10°C. Atmosphere control was accomplished in micro-chambers where the following atmospheric combinations were established: 3% O2 + 10% CO2 (N2 balance), 3% O2 + 15% CO2 (N2 balance), and Ambient atmosphere (control). Fruits were evaluated at 0, 3, 7 and 10 days for mass loss, firmness, pH, titratable acidity, soluble solids, sugars (sucrose, fructose and glucose), total anthocyanins, color (L-value, a-value), and microbiological quality. Sensory analysis was performed at 3, 7 and 10 days of storage, and appearence, texture and flavor were evaluated. There were no significant differences among most of the variables studied both at 5ºC and 10°C. Storage atmosphere had a significant effect in mass loss, firmness, levels of fructose and total anthocyanins and luminosity at the cut site. Atmospheres with 3% O2 + 10% CO2 and 3% O2 + 15% CO2 were more efficient in firmness maintenance for fresh-cut fruits as well as were more effective to control mass loss at normal atmosphere (air). However, fresh cut fruits kept in these atmospheres showed a lower content of total anthocyanins, although no significant changes were observed throughout the storage period. The presence of off-flavors detected by the taste panel in the fresh-cut strawberries stored under 3% O2 + 10% CO2 and 3% O2 + 15% CO2 made with that the product was rejected by the provers from 3rd day of storage, when the appearance was still adequate. Storage at 5°C was more effective in the maintenance of appearance, flavor retention and in the prevention of off-flavors. Storage length did not affect texture and flavor attributes evaluated by the sensory panel, but affected visual attributes. Temperature reduction from 10ºC to 5°C and the utilization of 3% O2 + 10% CO2 and 3% O2 + 15% CO2 concentrations reduced the growth of psycotrophic bacteria, molds and yeasts, increasing the shelf life of fresh-cut strawberries
Mestrado
Tecnologia Pós-Colheita
Mestre em Engenharia Agrícola

Thesis: Ph. D., Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 137-153).
Each year, surface ocean ecosystems export sinking particles containing gigatons of carbon into the ocean's interior. This particle flux connects the entire ocean microbiome and constitutes a fundamental aspect of marine microbial ecology and biogeochemical cycles. Particle flux is also variable and intricately complex, impeding its mechanistic or quantitative description. In this thesis we pair compilations of available data with novel mathematical models to explore the relationships between particle flux and other key variables - temperature, net primary production, and depth. Particular use is made of (probability) distributional descriptions of quantities that are known to vary appreciably. First, using established thermodynamic dependencies for primary production and respiration, a simple mechanistic model is developed relating export efficiency (i.e. the fraction of primary production that is exported out of the surface ocean via particle flux) to temperature.
The model accounts for the observed variability in export efficiency due to temperature without idealizing out the remaining variability that evinces particle flux's complexity. This model is then used to estimate the metabolically-driven change in average export efficiency over the era of long-term global sea surface temperature records, and it is shown that the underlying mechanism may help explain glacial-interglacial atmospheric carbon dioxide drawdown. The relationship between particle flux and net primary production is then explored. Given that these are inextricable but highly variable and measured on different effective scales, it is hypothesized that a quantitative relationship emerges between collections of the two measurements - i.e. that they can be related not measurement-by-measurement but rather via their probability distributions.
It is shown that on large spatial or temporal scales both are consistent with lognormal distributions, as expected if each is considered as the collective result of many subprocesses. A relationship is then derived between the log-moments of their distributions and agreement is found between independent estimates of this relationship, suggesting that upper ocean particle flux is predictable from net primary production on large spatiotemporal scales. Finally, the attenuation of particle flux with depth is explored. It is shown that while several particle flux-versus-depth models capture observations equivalently, these carry very different implications mechanistically and for magnitudes of export out of the surface ocean. A model is then proposed for this relationship that accounts for measurements of both the flux profile and of the settling velocity distribution of particulate matter, and is thus more consistent with and constrained by empirical knowledge.
Possible future applications of these models are discussed, as well as how they could be tested and/or constrained observationally.
by Brendan Barry.
Ph. D.
Ph.D. Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)

Thesis (M.S. in Combat Systems Technology)--Naval Postgraduate School, Dec. 2004.
Thesis Advisor(s): Gamani Karunasiri, Richard C. Olsen. Includes bibliographical references (p. 57-60). Also available online.

L’émergence et la multiplication de moyens d’observation du sol de résolution croissante et de réseaux de télécommunication spatiaux à très haut débit pour l’internet globalisé rendent nécessaire d’accroître la capacité de transmission de données entre l’espace et le sol de plusieurs ordres de grandeur. Les liens optiques, avec des débits de plusieurs dizaines de Gbps par canal, constituent une solution à très fort potentiel si les techniques de modulation de phase exploitées dans les réseaux fibrés peuvent y être appliquées. L’enjeu de cette thèse est d’investiguer le recours à des méthodes de modulation de phase pour des liens optiques satellite-sol en prenant en compte les spécificités propres à l’application : bruits de phase des lasers, effet Doppler, et impact de la propagation à travers l’atmosphère turbulente corrigé par optique adaptative pour maximiser l’efficacité de la détection cohérente. Dans ce but, j’ai développé un outil de simulation complète d’une transmission cohérente BPSK incluant les étapes de propagation à travers l’atmosphère, de détection et de démodulation. En s’appuyant sur cet outil, nous avons proposé deux architectures de récepteur numérique : l’une exploitant une boucle à verrouillage de phase, l’autre reposant sur une synchronisation en boucle ouverte. La méthodologie de conception développée à cette occasion permet de réduire l’impact du bruit de phase des lasers sur la précision de synchronisation, ce terme restant néanmoins prépondérant. L’étude menée montre que les deux architectures présentent des performances comparables en termes de précision de synchronisation, de seuil de convergence et de taux d’erreur dans différentes conditions de turbulence. Les performances en taux d’erreur obtenues soulignent l’importance de la qualité de la correction par optique adaptative. Une confirmation par modélisation du faible impact du bruit de phase turbulent sur la performance est apportée. Ces travaux laissent envisager la possibilité d’un accroissement très significatif du débit atteignable pour des liens de télémesure cohérents dans le cas de l’emploi de constellations d’ordre supérieur (QPSK et au-delà) au prix d’une correction par optique adaptative de bonne qualité
Both the increasing imaging resolution of earth observation satellites and the advent of a space-based globalized internet are currently urging for very high data rate transmissions between space and ground.With the promise to provide tens of Gbps per channel, optical links may become a major breakthrough technology, assuming that the technological assets developed for the fibered networks can be exploited. Especially, phase modulation techniques have demonstrated their tremendous efficiency for fibered networks. The aim of this thesis was to investigate the feasibility of their transposition to the case of satellite-to-ground optical links, accounting for their specificities: laser phase noise, Doppler effect, and the impact of propagation through the turbulent atmosphere and its correction by adaptive optics to maximize coherent detection efficiency. To investigate the main limitations of such a BPSK modulated coherent link, I developed a tool performing a detailed simulation of the data transmission process. It includes the beam propagation through the atmosphere, the atmospheric disturbances correction by adaptive optics, and the synchronization step necessary to recover the modulated phase. We investigated two architectures of digital receiver: one based on a phase-locked loop, and the other one based an open loop approach. We formalized a design methodology to reduce the impact of laser phase noise on the accuracy of synchronization. Laser phase noise remains however the main contributor to the residual phase error. The two architectures achieve comparable performance in terms of residual phase error, convergence threshold and error rate. The impact of atmospheric turbulence and its correction by adaptive optics was investigated for different turbulence conditions. As expected, the importance of the quality of the adaptive optics correction is highlighted. We confirm by modeling the limited impact of turbulent phase noise on the performance.This work opens prospects for a strong increase in the achievable bit rate for coherent telemetry links when using higher-order constellations (QPSK and beyond)

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Durante a exploração de uma mina, vários impactos são causados no meio ambiente, entre eles a geração da drenagem ácida de minas (DAM), que consiste da exposição de minerais sulfetados ao ar, água e microorganismos do tipo ferroxidantes, apresentando reações de oxidação e formação de ácido sulfúrico solubilizando metais ali presentes contaminando o solo e as águas. O objetivo deste trabalho de pesquisa foi estudar uma solução tecnológica fazendo uso da oxidação avançada com ozônio de metais pesados presentes em efluentes contaminados, em mina de urânio, com especial foco na remoção do manganês. A mina de urânio das Indústrias Nucleares do Brasil INB, em Caldas, Minas Gerais, local de aplicação deste estudo, enfrenta o problema da DAM e tem como principais contaminantes de suas águas superficiais os elementos, alumínio (Al), manganês (Mn), zinco (Zn), ferro (Fe), sulfatos (SO4+2), fluoretos (F-), metais de terras raras, alem do urânio (U) e do tório (Th). Os testes com ozônio realizados em laboratório com os efluentes da INB e in situ, mostraram uma grande eficiência para remoção do ferro, manganês e cério em até 99%. A concentração total de manganês ficou abaixo dos limites estabelecidos pela resolução 430 e 357 do CONAMA. Elementos como neodímio (Nd), lantânio (La) e zinco (Zn) pouco se oxidam com O3. O Al se mantém praticamente inalterado, enquanto que o tório e o urânio decaem, mas com o passar do tempo de ozonização voltam a se concentrar, porém com um valor inferior ao inicial. O precipitado obtido após a ozonização consiste de até 85% de oxido de manganês. A fim de descartar, após a ozonização, o efluente líquido para o ambiente é necessário uma correção do pH, de modo a atender os parâmetros da legislação CONAMA, sendo utilizado 50 a 86% menos reagente (CaOH2), do que as quantidades utilizadas no processo adotado pela INB.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Les capteurs hyperspectraux, qui acquièrent des images dans le domaine réflectif ([0,4-2,5 m]), avec une haute résolution spatiale (quelques mètres) et dans de nombreuses bandes spectrales simultanément, permettent d'estimer à la fois les propriétés des aérosols atmosphériques et de certains gaz. Les travaux présentés ici portent sur la caractérisation de panaches industriels. Les particules émises par les industries ont des propriétés encore très mal connues et les bases de données actuelles ne contiennent pas les informations nécessaires à la compréhension et la modélisation de leur impact radiatif. La première partie de cette étude consiste donc à caractériser les propriétés physiques et optiques de ces aérosols, à partir d'échantillons prélevés, et a conduit à l'établissement d'un modèle permettant de décrire l'impact radiatif d'un panache émis par une industrie métallurgique. Dans une seconde partie, une méthode d'estimation conjointe du CO2 et des aérosols est proposée. Il a été montré, à partir d'une étude de sensibilité et de l'application de cette méthode sur deux images AVIRIS, que cette estimation conjointe, dans le cas des panaches optiquement denses, conduisait à une erreur d'estimation du CO2 divisée d'un facteur 2 par rapport aux techniques existantes (e.g. JRGE). Enfin, une méthode d'estimation du type d'aérosols, EARTH (Estimation of Aerosol Type using Hyperspectral data), spécifiquement adaptée aux panaches industriels, a été développée. Une validation sur données simulées et réelles (image CASI) a montré qu'elle permettait de reconnaître, sans information a priori, la présence de particules métalliques dans un panache de faible épaisseur optique.

The effects on image formation through a tilted interference filter in a converging beam are investigated and an adequate compensation procedure is established. A method that compensates for small-scale seeing distortions is also developed with the aim of co-aligning non-simultaneous solar images from different passbands. These techniques are applied to data acquired with a narrow tiltable filter at the Swedish 1-meter Solar Telescope. Tilting provides a way to scan the wing of the Ca II H line. The resulting images are used to map the temperature stratification and vertical temperature gradients in a solar active region containing a sunspot at a resolution approaching 0''10. The data are compared with hydro-dynamical quiet sun models and magneto-hydrodynamic models of plage. The comparison gives credence to the observational techniques, the analysis methods, and the simulations. Vertical temperature gradients are lower in magnetic structures than in non-magnetic. Line-of-sight velocities and magnetic field properties in the penumbra of the same sunspot are estimated using the CRISP imaging spectropolarimeter and straylight compensation adequate for the data. These reveal a pattern of upflows and downflows throughout the entire penumbra including the interior penumbra. A correlation with intensity positively identifies these flows as convective in origin. The vertical convective signatures are observed everywhere, but the horizontal Evershed flow is observed to be confined to areas of nearly horizontal magnetic field.  The relation between temperature gradient and total circular polarization in magnetically sensitive lines is investigated in different structures of the penumbra. Penumbral dark cores are prominent in total circular polarization and temperature gradient maps. These become longer and more contiguous with increasing height. Dark fibril structures over bright regions are observed in the Ca II H line core, above both the umbra and penumbra.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.

A geração de resíduos sólidos é inerente ao desenvolvimento humano. O concreto armado é um dos materiais mais utilizados pelo homem e tem o cimento Portland como seu principal constituinte, o qual é produzido pela moagem de clínquer e gesso. O clínquer pode ser definido como um mineral artificial, obtido a partir das reações físico-químicas de calcário, argila e corretivos a altas temperaturas, em forno rotativo industrial, mediante a queima de combustíveis fósseis. No início da década de 70 foram realizadas as primeiras experiências de substituição de combustíveis fósseis por resíduos industriais nos Estados Unidos e países europeus, através da técnica denominada co-processamento, resultando na manufatura de um produto ao mesmo tempo em que os resíduos eram eliminados. O co-processamento se baseia na recuperação da energia disponível nos resíduos, substituindo parte daquela fornecida pelos combustíveis tradicionais ou na substituição de matérias-primas por resíduos com características químicas semelhantes àquelas normalmente empregadas na produção do clínquer. No estado de São Paulo as primeiras iniciativas para a utilização de resíduos industriais em fornos de clínquer ocorreram no início da década de 90. A partir de 1997 os órgãos ambientais de alguns estados brasileiros normatizaram procedimentos de licenciamento da atividade que foi, posteriormente, uniformizada por norma em âmbito federal. No ano de 1995 a Companhia de Cimento Ribeirão Grande/SP, Brasil, iniciou os procedimentos visando a substituição parcial dos combustíveis utilizados nos fornos rotativos por uma mistura de resíduos industriais. No período de 1995 a 2002 foram realizadas campanhas de amostragens em chaminés para avaliação das emissões atmosféricas dos dois fornos de produção de clínquer. A análise dos resultados obtidos associada às demais informações disponíveis de monitoramento das características das matérias-primas e combustíveis utilizados, bem como dos produtos finais, clínquer e cimento, não evidenciou alterações significativas nos níveis de emissões atmosféricas, sobretudo de material particulado e óxidos de enxofre, que pudessem ser associadas à utilização dos resíduos. Foram confirmadas as baixas emissões de inorgânicos e evidenciado o papel representado pelos resíduos no aporte dessas substâncias no sistema-forno, concluindo-se que esse aporte pode ser tão ou mais importante pela via da alimentação da farinha, cujos teores estão associados às características das jazidas minerais utilizadas. Foi também confirmada a alta eficiência do sistema-forno na destruição e remoção dos compostos orgânicos perigosos alimentados durante os testes de queima.
The production of industrial residues in inherent to the human development. The cement concrete is one of the most used material, manly the type portland cement, which is constituted by grinding clinker and gypsum together. Clinker can be defined as an artificial mineral obtained by applying physico-chemical reactions, at very high temperatures, to an appropriated mixture of limestone, clay, and some other materials in a rotating industrial kiln wich burns fossil fuels. In the early 1970 decade occurred the first experiences substituting fossil fuels by organic residues in USA and Europe through a technique named co-processing that results the production of certain manufacture while eliminates residues. Co-processing is based in the recovery of thermal energy and/or the mass of some constituents from some residues, with the same chemical characteristics of normal sources of energy, then economizing fuels and mass constituents and making better use of residues, otherwise useless and environmentally polluters. In the state of São Paulo this practice began in early 1990 decade and by 1997 it was started the standardization of the rules for its use in some units of the federation. Later this activity was regulated by nationally approved standard rules. In 1995 the industry Companhia de Cimento Ribeirão Grande (CCRG), a cement plant located in the city of Ribeirão Grande, São Paulo state, Brazil, started procedures searching the partial substitution of the normal fuels by a mixture of industrial residues in its two rotating kilns. The gaseous emissions from the chimneys of these two clinker kilns were studied from 1995 to 2002 about the use of residues as part of the fuel. Analyses of the final results associated with other informations concerning to the quality of raw minerals, fuels and products did not show significant alterations in atmospheric emissions, mainly for particulate material and sulfur oxides, related with the use of residues. The emissions of inorganic continued to be low and not significantly altered by the presence of residues. It was possible to conclude that the alterations in inorganic emissions depend more from the quality of the raw minerals feed in the kilns, which is more difficult to control, than from the presence of residues being burn with the fuel. It was shown a high efficiency in the destruction of dangerous organic compounds feed in the cement kilns, under test conditions.

A relative, lie-value image normalisation (LVIN) procedure was investigated as a means of estimating surface reflectances from sequences of Landsat TM and ETM+ imagery, and standardising image data for change detection studies when there are uncertainties in sensor calibration and atmospheric parameters over time. The basis of the LVIX procedure is that for an A-date sequence, the digital numbers (DNs) of N-1 overpass images can be mapped to the reflectance values of a reference image for a set of pseudo- invariant targets (PITs) common to all images in the sequence. The robust M-estimator was employed to provide the transformation function that achieved the mapping. The investigation also showed that in some instances the LVIN procedure could incorporate the modelled Path DN-the modelled DN for a target of zero surface reflectance. A lack of surface validation data was a limitation in the investigation. However, a qualitative evaluation of the LVIN procedure was possible by examining the pre- and post-normalisation image histograms. In a comparison with the results of the 6S radiative transfer code, it war observed that when both overpass and reference images were acquired with the same sensor, the LVIK procedure appeared t o correct for atmospheric effects; and when overpass and reference images were with different sensors, the LVIN procedure also corrected for between-sensor differences. Moreover, it was demonstrated for the more "temporally-invariant" PITs that the procedure retrieved surface reflectances that were on average within ±0.02 reflectance units.
The ability of the LVIK procedure to standardise sequences of image data was further demonstrated in the study of vegetation change. The normalised difference vegetation index (NDVI) was calculated from LVIN estimates of surface reflectance for a selection of sites around the township of Mt. Barker, Western Australia. NDVI data had characteristics consistent with data that have been corrected for atmospheric effects. A modification to the LVIN procedure was also proposed based on an investigation of some empirically-derived vegetation reflectance relationships. Research into the robustness of the relationships for a greater range of vegetation types is recommended.

Dans ce manuscrit, nous avons exploré la non-linéarité et la non stationnarité de la variabilité hydroclimatique en France et dans la zone Euro-Atlantique. Dans la partie I « Échelles spatiotemporelles de la variabilité hydroclimatique en France », nous avons réalisé les classifications spatiales de précipitations, températures et débits de 152 bassins versants, basées sur les caractéristiques spectrales non-stationnaires de ces variables, puis étudier comment ces caractéristiques spectrales interagissaient entre elles. Nous avons montré que les régions de variabilité hydroclimatique homogène étaient spatialement continues, et de superficie très différentes. Les interactions spectrales dans chaque région homogène sont très complexes, et deux régions aux propriétés spectrales similaires, peuvent être le siège de différentes interactions. Dans la Partie II « Échelles spatiotemporelles de la variabilité hydroclimatique large échelle », nous avons tout d’abord exploré la modulation exprimée sur les entrées de précipitation et température par les caractéristiques du bassin versant. Nous avons montré que la température montre un lien direct avec les débits à l’échelle annuelle, tandis que la précipitation est directement liée aux débits pour les échelles saisonnières, 2-4 et 5-8 ans. Ensuite, nous avons étudié la variabilité climatique large échelle liée aux précipitations et débits, via l’analyse composite et de corrélation spectrale de champs de géopotentiels à 500hPa. Les régimes de géopotentiels liés aux précipitations et débits sont différents en fonction des échelles de temps considérées, et en fonction de la zone considérées, les corrélations se font à différentes échelles, montrant la non-linéarité des liens entres climat large échelle et hydroclimat local. Enfin, dans la Partie III « Dynamique de la circulation atmosphérique Nord Atlantique, et variabilité hydroclimatique », nous avons exploré les propriétés dynamiques d’un objet géométrique, invariant conforme, la longueur extrémale. Nous avons montré qu’une longueur extrémale de dérivée nulle implique une dynamique constante, c’est-à-dire, une dynamique dont les équations de mouvement respectent certaines lois de conservation. L’application de ces résultats théoriques sur la variabilité atmosphérique dans la zone Nord Atlantique montre que la dynamique des géopotentiels peut changer et que les régimes de temps, extrapolés statistiquement, ne sont pas représentatifs d’une seule dynamique. L’ensemble des dynamiques possibles, ainsi que leur stabilité et stationnarité, dépend de l’échelle temporelle considérée.À travers les résultats présentés dans ce manuscrit, nous avons montré l’importance de prendre en compte la non-linéarité (i.e. les interactions entre les composants du système climatique qui peuvent donner lieu à des comportements complexes) et la non-stationnarité (i.e. les changements brusques de dynamiques dus aux changements de paramètres de contrôle) de la variabilité hydroclimatique. A minima, la prise en compte des différences de dynamiques en fonction des échelles de temps est cruciale. Idéalement, la prise en compte simultanée des variabilités spatiales, temporelles et dynamiques devrait être encouragée
The works presented in this thesis explore the non-linearity and non-stationarity aspects of the hydroclimate system in France and the Euro-Atlantique area. In part I, «Spatio-temporal scales of hydroclimate variability in France», classifications of precipitation, temperature and discharge time series of 152 watersheds were established, based on non-linear and non-stationary characteristics. In particular, we based our classifications on spectral contents and cross-scale, phase-phase, phase-amplitude interactions. Results show clear homogeneous regions for each variable, but with complex spectral content and cross-scale interactions. Part II, « Spatiotemporal of local and large-scale climate variability», we studied how the watershed modulation altered the spectral correlation between local climate (precipitation, temperature) and discharge. We then studied the large-scale atmospheric patterns linked to discharge, with a combined spatial and temporal spectral analysis. Results show than temperature is the main driver of discharge at the annual scale, but precipitation is the main driver for other time scales. The large scale atmospheric patterns linked to discharge were shown to be time scale dependent and heavily modulated from West to east, with interacting atmospheric components shifting the main time scales of spectral correlation with discharge. Finally, Part III « North Atlantic atmospheric circulation dynamics», introduces a new conjecture linking the geometrical theory of the extremal length (a conformal invariant) and conservative atomspheric systems, such as the North Atlantic atmospheric circulation. We have shown that the time invariance of the extremal length implies conservation in mechanical energy within the atmospheric system, and that the increase/decrease of invariance induces mechanical energy losses/gains. The application of the theory to the North Atlantic atmospheric circulation, shows that depending on the time scale, the dynamics are vastly different, ranging for asymptotically stable to unstable, and that the atmospheric circulation for the last 40 years has seen large changes in its dynamics. Through this thesis, we showed the importance of time scale dependence, interactions between them, and more generally, of non-linearity and non-stationarity. We encourage hydrologist and climate scientists to adopt a combined physics-statistical approach in order to better grasp the complexity of hydroclimate systems

This Ph.D. thesis addresses remote sensing of the atmosphere by means of lidar and S-band clear-air weather radar, and related data signal processing. Active remote sensing by means of these instruments offers unprecedented capabilities of spatial and temporal resolutions for vertical atmospheric profiling and the retrieval of key optical and physical atmospheric products in an increasing environmental regulatory framework. The first goal is this Ph.D. concerns the estimation of error bounds in the inversion of the profile of the atmospheric backscatter coefficient from elastic lidar signals (i.e., without wavelength shift in reception when interacting with atmospheric scatterers) by means of the two-component inversion algorithm (the so-called Klett-Fernald-Sasano¿s algorithm). This objective departs from previous works at the Remote Sensing Lab. (RSLab) of the Universitat Politècnica de Catalunya (UPC) and derives first-order error-propagated bounds (approximate) and total-increment bounds (exact). As distinctive feature in the state of the art, the error bounds merge into a single body both systematic (i.e., user-calibration inputs) and random error sources (finite signal-to-noise ratio, SNR) yielding an explicit mathematical form. The second goal, central to this Ph.D., tackles retrieval of the Atmospheric Boundary Layer Height (ABLH) from elastic lidar and S-band Frequency-Modulated Continuous-Wave (FMCW) radar observations by using adaptive techniques based on the Extended Kalman Filter (EKF). The filter is based on morphological modelling of the Mixing-Layer-to-Free-Troposphere transition and continuous estimation of the noise covariance information. In the lidar-EKF realization the proposed technique is shown to outperform classic ABLH estimators such as those based on derivative techniques, thresholded decision, or the variance centroid method. The EKF formulation is applied to both ceilometer and UPC lidar records in high- and low-SNR scenes. The lidar-EKF approach is re-formulated and successfully extended to S-band radar scenes (Bragg¿s scattering) in presence of interferent noise sources (Rayleigh scattering from e.g., insects and birds). In this context, the FMCW feature enables the range-resolved capability. EKF-lidar and EKF-radar ABLH estimates are cross-examined from field campaign results. Finally, the third goal deals with exploitation of the existing UPC lidar station: In a first introductory part, a modified algorithm for enhancing the dynamic range of elastic lidar channels by ¿gluing¿ analog and photon-counting data records is formulated. In a second part, two case examples (including application of the gluing algorithm) are presented to illustrate the capabilities of the UPC lidar in networked atmospheric observation of two recent volcano eruption events as part of the EARLINET (European Aerosol Research Lidar Network). The latter is part of GALION (Global Atmospheric Watch Atmospheric Lidar Observation Network)-GEOSS (Global Earth Observation System of Systems) framework.
La tesis doctoral aborda la teledetecció atmosfèrica amb tècniques lidar i radar (banda S) i llur tractament del senyal. La teledetecció activa amb aquests instruments ofereix resolucions espacials i temporals sense precedents en la perfilometria vertical de l'atmosfera i recuperació de productes de dades òptics i físics atmosfèrics en un marc de creixent regulació mediambiental. El primer objectiu d'aquesta tesi concerneix l'estimació de cotes d'error en la inversió del perfil del coeficient de retrodispersió atmosfèrica a partir de senyals lidar de tipus elàstic (és a dir, sense desplaçament de la longitud d'ona en recepció al interactuar amb els dispersors atmosfèrics) mitjançant l'algorisme d'inversió de dues components de Klett-Fernald-Sasano. Aquest objectiu parteix de treballs previs en el Remote Sensing Lab. (RSLab) de la Universitat Politècnica de Catalunya (UPC) i permet obtenir cotes de primer ordre (aproximades) basades en propagació d'errors i cotes (exactes) basades en el increment total de l'error. Característica diferencial en front l'estat de l'art és l'assimilació d'errors sistemàtics (per exemple, entrades de cal.libració d'usuari) i aleatoris (relació senyal-soroll, SNR, finita) en forma matemàtica explícita. El segon objectiu, central de la tesis, aborda l'estimació de l'altura de la capa límit atmosfèrica (ABLH) a partir de senyal lidar elàstics i d'observacions radar en banda S (ona continua amb modulació en freqüència, FMCW) utilitzant tècniques adaptatives basades en filtrat estès de Kalman (EKF). El filtre es basa en modelat morfològic de la transició atmosfèrica entre la capa de mescla i la troposfera lliure i en l'estimació continua de la informació de covariança del soroll. En el prototipus lidar-EKF la tècnica proposada millora clarament les tècniques clàssiques d'estimació de la ABLH como són les basades en mètodes derivatius, decisió de llindar, o el mètode de la variança-centroide. La formulació EKF s'aplica tant a mesures procedents de ceilòmetres lidar como de la pròpia estació lidar UPC en escenes d'alta i baixa SNR. Addicionalment, l'enfoc lidar-EKF es reformula i s'estén amb èxit a escenes radar en banda S (dispersió Bragg) en presència de fonts de soroll interferent (dispersió Rayleigh de, per exemple, insectes i ocells). En aquest context, la característica FMCW permet la capacitat de resolució en distància. L'estimació de la ABLH amb els prototipus lidar-EKF i radar-EKF s'intercompara en campanyes de mesura. Finalment, el tercer objectiu atén a l'explotació de l'estació lidar UPC existent: En una primera part introductòria, es formula un algorisme modificat de "gluing" per a la millora del marge dinàmic de canals lidar elàstics mitjançant combinació (o "enganxat") de senyals lidar adquirits analògicament i amb foto-comptatge. En una segona part, es presenten dos exemples (incloent l'aplicació de l'algorisme de "gluing") que il.lustren les capacitats del lidar de la UPC en l'observació atmosfèrica de dos recents erupcions volcàniques des de la xarxa d'observació EARLINET (European Aerosol Research Lidar Network). Aquesta última és part de GALION (Global Atmospheric Watch Atmospheric Lidar Observation Network)-GEOSS (Global Earth Observation System of Systems).

This thesis presents algorithms for performing the next two reduction steps, namely orthogonalization and extraction. More specifically, this thesis addresses the following research question: What are proper methods of orthogonalizing spectral images in preparation for extraction?

Dans la troposphère, le rayonnement électromagnétique hyperfréquence interagit avec la matière suivant trois processus : l'absorption par les molécules de gaz et d'eau, la diffusion due à la redirection de l'onde par les hydrométéores, et l'émission par les particules absorbantes d'un rayonnement naturel incohérent. Mes travaux ont pour base commune ces processus d'interaction des ondes électromagnétiques avec l'atmosphère, et concernent deux domaines distincts : la télédétection spatiale de l'atmosphère et les télécommunications Terre-satellite. J'ai développé une méthodologie originale de mise au point d'algorithmes neuronaux pour l'observation de l'atmosphère à partir de capteurs hyperfréquences passifs. Mes travaux ont mis en évidence la capacité des réseaux de neurones à restituer les paramètres physiques des phénomènes sous-jacents aux observations. Une amélioration des performances globales de la restitution des grandeurs atmosphériques est obtenue grâce à la modélisation de relations non linéaires que permet cette approche. Les perspectives multiples qu'offrent, en géophysique, l'emploi d'une architecture neuronale modulaire, ou l'utilisation des cartes de Kohonen, sont soulignées. L'évolution des systèmes de télécommunication hyperfréquence par satellites, pousse à utiliser des fréquences de plus en plus élevées. Aux fréquences supérieures à 20 GHz l'atmosphère est à l'origine de la dégradation de la qualité des liaisons. Je présenterai les campagnes de mesures, et les travaux de modélisation réalisés, dans le cadre de la mise au point de nouvelles techniques de lutte contre les affaiblissements (Fade Mitigation Technique). L'originalité de mes recherches relatives à la modélisation du canal de propagation réside dans l'usage de modélisations statistiques du type TARIMA GARCH, qui s'attachent, plutôt que de prévoir le comportement moyen du processus, à prévoir la variabilité et donc le risque d'un comportement extrême.

Mestrado em Engenharia Alimentar - Processamento de Alimentos - Instituto Superior de Agronomia
In this study correlations between Rocha pear quality attributes and the incidence of internal browning (IB) were performed in order to know the major factors which determine different susceptibility of the fruit. Fruits under study were previously stored in dynamic controlled atmosphere (four months) and from three geographical origins (west region). The fruit incidence of IB showed to be dependent on geographical production localization. Fruits from Mafra and Lourinhã with 28 and 43% of IB, respectively, versus Alcobaça, where no symptoms were detected (0% IB). Fruits from Alcobaça showed the highest contents of ascorbic acid (AA) (4,8 mg/100 g) and of total phenolic compounds (CFT) (111,0 mg CAE/100 g), with increases of 20% and 40%, respectively, in comparison to the others, representing these the most distinctive quality factors. It was found that fruits with more calcium content, lesser potassium content and higher antioxidant capacity are more resistant to IB. By other side, the symptoms incidence is bigger in advanced post-harvest ripeness stages and minor AA content. The effects of AA content of the fruit on IB incidence were inconclusive. However, in the fruit core tissues the presence of similar AA contents between fruits, with and without IB, along with significant differences in CFT, could suggest that phenolic compounds are involved as a stress response to internal browning disorders mechanisms. Full ripening capacity was achieved in 4 days (room temperature) regardless fruits origin. However, fruits with higher internal browning incidence showed lesser storage ability (5 C), as a fresh-cut product

Die chemische Zusammensetzung und die physikalischen Eigenschaften von troposphärischen Gasen, Partikeln und Wolken hängen aufgrund zahlreicher Prozesse stark voneinander ab. Insbesondere chemische Multiphasenprozesse in Wolken können die physiko-chemischen Eigenschaften der Luft und troposphärischer Partikel klein- und großräumig verändern. Diese chemische Prozessierung des troposphärischen Aerosols innerhalb von Wolken beeinflusst die chemischen Umwandlungen in der Atmosphäre, die Bildung von Wolken, deren Ausdehnung und Lebensdauer, sowie die Transmissivität von einfallender und ausgehender Strahlung durch die Atmosphäre. Damit sind wolken-chemische Prozesse relevant für das Klima auf der Erde und für verschiedene Umweltaspekte. Daher ist ein umfassendes Verständnis dieser Prozesse wichtig. Die explizite Behandlung chemischer Reaktionen in der Flüssigphase stellt allerdings eine Herausforderung für atmosphärische Computermodelle dar. Detaillierte Beschreibungen der Flüssigphasenchemie werden deshalb häufig nur für Boxmodelle verwendet. Regionale Chemie-Transport-Modelle und Klimamodelle berücksichtigen diese Prozesse meist nur mit vereinfachten chemischen Mechanismen oder Parametrisierungen. Die vorliegende Arbeit hat zum Ziel, den Einfluss der chemischer Mehrphasenprozesse innerhalb von Wolken auf den Verbleib relevanter Spurengase und Partikelbestandteile mit Hilfe des state‑of‑the‑art 3D-Chemie-Transport-Modells COSMO-MUSCAT zu untersuchen. Zu diesem Zweck wurde das Model um eine detaillierte Beschreibung chemischer Prozesse in der Flüssigphase erweitert. Zusätzlich wurde das bestehende Depositionsschema verbessert, um auch die Deposition von Nebeltropfen zu berücksichtigen. Die durchgeführten Modellerweiterungen ermöglichen eine bessere Beschreibung des troposphärischen Multiphasensystems. Das erweiterte Modellsystem wurde sowohl für künstliche 2D-Bergüberströmungsszenarien als auch für reale 3D-Simulationen angewendet. Mittels Prozess- und Sensitivitätsstudien wurde der Einfluss (i) des Detailgrades der verwendeten Mechanismen zur Beschreibung der Flüssigphasenchemie, (ii) der Größenauflösung des Tropfenspektrums und (iii) der Tropfenanzahl auf die chemischen Modellergebnisse untersucht. Die Studien belegen, dass die Auswirkungen der Wolkenchemie aufgrund ihres signifikanten Einflusses auf die Oxidationskapazität in der Gas- und Flüssigphase, die Bildung von organischer und anorganischer Partikelmasse sowie die Azidität der Wolkentropfen und Partikel in regionalen Chemie-Transport-Modellen berücksichtigt werden sollten. Im Vergleich zu einer vereinfachten Beschreibung der Wolkenchemie führt die Verwendung des detaillierten chemischen Flüssigphasenmechanismus C3.0RED zu verringerten Konzentrationen wichtiger Oxidantien in der Gasphase, einer höheren Nitratmasse in der Nacht, geringeren nächtlichen pH-Werten und einer veränderten Sulfatbildung. Darüber hinaus ermöglicht eine detaillierte Wolkenchemie erst Untersuchungen zur Bildung sekundärer organischer Partikelmasse in der Flüssigphase. Die größenaufgelöste Behandlung der Flüssigphasenchemie hatte nur geringen Einfluss auf die chemischen Modellergebnisse. Schließlich wurde das erweiterte Modell für Fallstudien zur Feldmesskampagne HCCT‑2010 genutzt. Zum ersten Mal wurde dabei ein chemischer Mechanismus mit der Komplexität von C3.0RED verwendet. Die räumlichen Effekte realer Wolken z. B. auf troposphärische Oxidantien oder die Bildung anorganischer Masse wurden untersucht. Der Vergleich der Modellergebnisse mit verfügbaren Messungen hat viele Übereinstimmungen aber auch interessante Unterschiede aufgezeigt, die weiter untersucht werden müssen
In the troposphere, a vast number of interactions between gases, particles, and clouds affect their physico-chemical properties, which, therefore, highly depend on each other. Particularly, multiphase chemical processes within clouds can alter the physico-chemical properties of the gas and the particle phase from the local to the global scale. This cloud processing of the tropospheric aerosol may, therefore, affect chemical conversions in the atmosphere, the formation, extent, and lifetime of clouds, as well as the interaction of particles and clouds with incoming and outgoing radiation. Considering the relevance of these processes for Earth\'s climate and many environmental issues, a detailed understanding of the chemical processes within clouds is important. However, the treatment of aqueous phase chemical reactions in numerical models in a comprehensive and explicit manner is challenging. Therefore, detailed descriptions of aqueous chemistry are only available in box models, whereas regional chemistry transport and climate models usually treat cloud chemical processes by means of rather simplified chemical mechanisms or parameterizations. The present work aims at characterizing the influence of chemical cloud processing of the tropospheric aerosol on the fate of relevant gaseous and particulate aerosol constituents using the state-of-the-art 3‑D chemistry transport model (CTM) COSMO‑MUSCAT. For this purpose, the model was enhanced by a detailed description of aqueous phase chemical processes. In addition, the deposition schemes were improved in order to account for the deposition of cloud droplets of ground layer clouds and fogs. The conducted model enhancements provide a better insight in the tropospheric multiphase system. The extended model system was applied for an artificial mountain streaming scenario as well as for real 3‑D case studies. Process and sensitivity studies were conducted investigating the influence of (i) the detail of the used aqueous phase chemical representation, (ii) the size-resolution of the cloud droplets, and (iii) the total droplet number on the chemical model output. The studies indicated the requirement to consider chemical cloud effects in regional CTMs because of their key impacts on e.g., oxidation capacity in the gas and aqueous phase, formation of organic and inorganic particulate mass, and droplet acidity. In comparison to rather simplified aqueous phase chemical mechanisms focusing on sulfate formation, the use of the detailed aqueous phase chemistry mechanism C3.0RED leads to decreased gas phase oxidant concentrations, increased nighttime nitrate mass, decreased nighttime pH, and differences in sulfate mass. Moreover, the treatment of detailed aqueous phase chemistry enables the investigation of the formation of aqueous secondary organic aerosol mass. The consideration of size-resolved aqueous phase chemistry shows only slight effects on the chemical model output. Finally, the enhanced model was applied for case studies connected to the field experiment HCCT-2010. For the first time, an aqueous phase mechanism with the complexity of C3.0RED was applied in 3‑D chemistry transport simulations. Interesting spatial effects of real clouds on e.g., tropospheric oxidants and inorganic mass have been studied. The comparison of the model output with available measurements revealed many agreements and also interesting disagreements, which need further investigations

Fatigue still represents one of the most detrimental causes of steel structure failure. Carbon fiber-reinforced polymer (CFRP) composites offer a good opportunity in structural repair because of their high strength-to-weight ratio and the possibility to obtain the material in different forms, which can fit all desirable geometries. Commonly, steel structures experience either service load and environmental exposure simultaneously, and however, the effect of this combination is still not analyzed enough nowadays, especially in fatigue terms. This paper highlights an experimental analysis of the fatigue performance of steel plates repaired with CFRP laminates subjected to the marine environment. Five degrees of initial damage to the steel plates were considered. The bond consisted of one layer of CFRP laminate adhesively bonded on both sides of the plate with two different patches, i.e., fully covered and partially covered. The specimens were exposed to a simulated marine atmosphere for up to one and six months. In order to reproduce service load stress, the plates were subjected to a static tensile load during exposure. After submergence, the fatigue life was tested at room temperature and the crack propagation was monitored throughout the beach marking technique. The effect of environmental exposure on the epoxy was also carefully investigated. The improvements provided by CFRP bonded to steel were successfully maintained after exposure to harsh environmental conditions although decrements of fatigue life were accounted after six months of exposure. The decrements of the fatigue life due to the environmental effect ranged from 3% to 30% compared to the unexposed specimens. Marine atmosphere mostly affected the integrity of the interfaces, since adhesion failures occurred progressively from one to six months of exposure. The work provides useful recommendations for practical purpose and it suggests topics which require further investigation.

[EN] Persimmon (Diospyros kaki L.) 'Rojo Brillante' is an astringent variety characterised by good growing conditions, excellent colour, size, sensory characteristics and good nutritional properties. In the last decade, its production has grown substantially in Spain given the application of high levels of CO2 to remove astringency while firmness is preserved. This technology has also increased its potential as a fresh-cut commodity. However, physical damage during processing result in degradation of the colour and firmness of the product and a higher susceptibility to microbial spoilage that significantly reduces the fruit's shelf life. The objective of the present thesis was to develop optimum procedures for processing and marketing 'Rojo Brillante' persimmon into a fresh-cut product with the maximum shelf life and best physicochemical, nutritional, sensory and microbiological quality. Firstly, the objective was to evaluate the effect of the maturity stage (MS) at harvest, storage time at 15 ºC before processing, and the application of different antioxidant treatments on enzymatic browning, sensory and nutritional quality of fresh-cut 'Rojo Brillante' persimmon during storage at 5 ºC. Concentrations of 10 g L-1 ascorbic acid (AA) or 10 g L-1 citric acid (CA) controlled tissue browning and maintained the visual quality of fresh-cut persimmon above the limit of marketability for 6-8 storage days at 5 ºC, depending on the MS. However, these acidic solutions reduced fruit firmness as compared to control samples. Further studies showed that the combination of these antioxidants with 10 g L-1 CaCl2 maintained firmness of the persimmon slices within the same range as the control samples. In another work, the application of 1-methylcyclopropene (1-MCP) allowed to process fruits after 45 days of storage at 1 ºC with commercial firmness and the antioxidant solution (10 g L-1 CA + 10 g L-1 CaCl2) extended the limit of marketability up to 9 days of storage at 5 ºC. Different controlled atmosphere conditions in combination with AA or CA dips were also evaluated as a first step to select optimum O2 and CO2 concentrations for modified atmosphere packaging (MAP) of fresh-cut 'Rojo Brillante' persimmons. Overall, the combination of antioxidant dips and a controlled atmosphere composed of 5 kPa O2 (balance N2) was proved to be the most effective combination to control enzymatic browning. This atmosphere maintained the visual quality of persimmon slices within the limit of marketability during 7- 9 days at 5 ºC. On the contrary, high CO2 concentrations (10 or 20 kPa) induced darkening in some tissue areas, associated with a flesh disorder known as 'internal flesh browning'. Later studies confirmed the beneficial effect of an active MAP in 5 kPa O2 compared to passive MAP to improve the visual quality of fresh-cut 'Rojo Brillante' persimmon, showing a synergic effect with the antioxidant dip (10 g L-1 CA + 10 g L-1 CaCl2). Antioxidant edible coatings were prepared from whey protein isolate (WPI), soy protein isolate (SPI), hydroxylpropyl methylcellulose (HPMC) and apple pectin as the polymeric matrix. All edible coatings were amended with the antioxidant combination selected (10 g L-1 CA + 10 g L-1 CaCl2). All the edible coatings tested proved effective to control enzymatic browning of persimmon slices. However, the samples treated with the HPMC- and pectin- based coatings were scored with a better visual quality that the rest of the treatments. In general, free radical scavenging activity and total carotenoid content increased in late-season persimmons; whereas, processing (cutting and storage at 5 ºC), antioxidant dips, controlled atmosphere storage or edible coatings had no clear effect on nutritional quality (vitamin C, free radical scavenging activity, total phenolic content, and carotenoids) of fresh-cut persimmons.
[ES] El caqui persimmon (Diospyros kaki L.) 'Rojo Brillante' es un cultivar astringente que presenta unas propiedades organolépticas y nutricionales excelentes. En la última década, su cultivo en el área mediterránea de España se ha incrementado de manera exponencial con el desarrollo de la tecnología que permite eliminar la astringencia, manteniendo la firmeza del mismo. Esta nueva forma de presentación, aporta numerosas ventajas, entre la que se incluye la posibilidad de ser comercializado como fruta fresca cortada. Sin embargo, el éxito comercial del producto está limitado por el pardeamiento enzimático, la pérdida de firmeza y al crecimiento microbiano. En este contexto, el objetivo de la Tesis ha sido el desarrollo de caqui 'Rojo Brillante' fresco cortado mediante un enfoque que integra el estudio de las características del producto en el momento del procesado y de distintas tecnologías que mantengan la calidad físico-química, sensorial, nutricional y microbiológica del producto durante un periodo que permita su comercialización. En primer lugar, se evaluó el efecto del estado de madurez (MS) en el momento de recolección, el tiempo de almacenamiento a 15 ºC antes del procesado y la aplicación de diferentes antioxidantes en el pardeamiento enzimático y la calidad sensorial y nutricional del caqui 'Rojo Brillante' cortado y almacenado a 5 ºC. La aplicación de 10 g L-1 de ácido ascórbico (AA) ó 10 g L-1 ácido cítrico (CA) controló el pardeamiento enzimático y mantuvo la calidad visual del caqui por encima del límite de comercialización entre 6 y 8 días de almacenamiento a 5 ºC, dependiendo del MS. Sin embrago, la aplicación de estos antioxidantes redujo de manera significativa la firmeza del fruto respecto al control. La combinación de estos antioxidantes con 10 g L-1 de CaCl2 permitió mantener la firmeza en el mismo rango que las muestras control. En un trabajo posterior, la aplicación de 1-metilciclopropeno (1-MCP) permitió procesar caqui almacenado 45 días a 1 ºC con una buena firmeza comercial y el tratamiento antioxidante (10 g L-1 CA + 10 g L-1 CaCl2) consiguió alcanzar un límite de comercialización del producto de 9 días a 5 ºC. La evaluación de distintas atmósferas controladas en combinación con tratamientos antioxidantes (AA o CA), como paso previo al envasado en atmósfera modificada (MAP) del caqui, mostró como más efectiva en el control del pardeamiento enzimático la atmósfera compuesta por 5 kPa O2 (balance N2). Esta atmósfera mantuvo la calidad visual del caqui cortado dentro del límite de comercialización durante 7-9 días a 5 ºC. Por el contrario, la aplicación de altas concentraciones de CO2 (10 ó 20 kPa) dio lugar a un pardeamiento en ciertas zonas de la pulpa que se conoce como 'internal flesh browning'. Estudios posteriores confirmaron el efecto beneficioso del envasado de caqui cortado y tratado con solución antioxidante (CA-CaCl2) en una MAP activa de 5 kPa O2 en la calidad visual del fruto frente a la aplicación de una MAP pasiva. El desarrollo de recubrimientos comestibles con capacidad antioxidante se realizó mediante la incorporación de antioxidantes (10 g L-1 CA + 10 g L-1 CaCl2) a formulaciones a base de proteína de suero lácteo (WPI), proteína de soja (SPI), hidroxipropilmetilcelulosa (HPMC) y pectina. Todos los recubrimientos fueron efectivos controlando el pardeamiento enzimático del caqui cortado, siendo las muestras recubiertas con HPMC y pectina las mejor evaluadas visualmente. En general, el procesado, la aplicación de antioxidantes, el envasado en atmósferas controladas y los distintos recubrimientos comestibles estudiados, si bien no mostraron un efecto claro en los parámetros de calidad nutricional evaluados, no tuvieron un efecto negativo en los mismos. Por otra parte, los frutos cosechados a final de campaña tuvieron mayor actividad antioxidante y contenido en carotenoides.
[CAT] El caqui persimmon (Diospyros kaki L.) 'Rojo Brillante' és un cultiu astringent que presenta unes propietats organolèptiques i nutricionals excel¿lents. En la última dècada, el seu cultiu en l'àrea mediterrània d'Espanya s'ha incrementat de manera exponencial amb el desenvolupament de la tecnologia que permet eliminar l'astringència, mantenint la fermesa del mateix. Esta nova forma de presentació, aporta un gran nombre d'avantatges, entre els quals s'inclou la possibilitat de comercialitzar-lo com fruita fresca processada. No obstant, l'èxit comercial del producte està limitat per pardetjament enzimàtic, la pèrdua de fermesa i el creixement microbià. L'objectiu de la Tesis ha estat en el desenvolupament de caqui 'Rojo Brillante' tallat en fresc mitjançant un enfocament que integra l'estudi de les característiques del producte en el moment del processat i de diferents tecnologies en el manteniment de la qualitat físico-química, sensorial, nutricional i microbiològica del producte durant un període que permeta la seua comercialització. En primer lloc, es va avaluar l'efecte de l'estat de maduresa (MS) en el moment de recol¿lecció, el temps d'emmagatzemament a 15ºC abans del processat i l'aplicació de diferents tractaments antioxidants en el pardetjament enzimàtic i la qualitat sensorial i nutricional del caqui 'Rojo Brillante' tallat i emmagatzemat a 5 ºC. L'aplicació de 10 g L-1 d'àcid ascòrbic (AA) o 10 g L-1 d'àcid cítric (CA) va controlar el pardetjament enzimàtic i va mantenir la qualitat visual del caqui per damunt del límit de comercialització entre 6-8 dies d'emmagatzemament a 5 ºC, depenent del MS. No obstant, l'aplicació d'antioxidants va reduir de manera significativa la fermesa del fruit comparat amb el control. La combinació d'aquestos antioxidants amb 10 g L-1 de CaCl2 va permetre mantenir la fermesa en el mateix rang que les mostres control. En un treball posterior, l'aplicació de 1-metilciclopropeno (1-MCP) va permetre processar caqui emmagatzemat 45 dies a 1 ºC amb una bona fermesa comercial i a més, el tractament antioxidant (10 g L-1 CA + 10 g L-1 CaCl2) va aconseguir un límit de comercialització del producte tallat de 9 dies a 5 ºC. L'avaluació de diferents atmosferes controlades en combinació amb tractaments antioxidants (AA o CA), com a pas previ a l'envasament en atmosfera modificada (MAP) del caqui 'Rojo Brillante, va mostrar com a més efectiva en el control del pardetjament enzimàtic l'atmosfera composta per 5 kPa O2 (balanç N2). Aquesta atmosfera va mantenir la qualitat visual del caqui tallat dins del límit de comercialització durant 7-9 dies a 5 ºC. Per contra, l'aplicació d'altes concentracions de CO2 (10 ó 20 kPa) va donar lloc a un pardetjament en certes zones de la polpa, el qual és conegut com 'internal flesh browning'. Estudis posteriors van confirmar l'efecte beneficiós de l'envasament de caqui tallat i tractat amb solució antioxidant (CA-CaCl2) en una MAP activa de 5 kPa O2 millorant la qualitat visual de la fruita front a l'aplicació de una MAP passiva. El desenvolupament de recobriments comestibles amb capacitat antioxidant es va realitzar mitjançant la incorporació d'antioxidants (CA-CaCl2) en formulacions a base de proteïna de sèrum làctic (WPI), proteïna de soia (SPI), hidroxipropilmetilcel-lulosa (HPMC) i pectina. Tots els recobriments van ser efectius controlant el pardetjament enzimàtic del caqui tallat. No obstant, les mostres recobertes amb HPMC i pectina van ser millor avaluades visualment que la resta de tractaments. En general, el processat, l'aplicació d'antioxidants, l'envasament en atmosferes controlades i els distints recobriments comestibles estudiats, si bé no van mostrar un efecte clar en els paràmetres de la qualitat nutricional avaluats, no van tindre un efecte negatiu en els mateixos. Per altra banda, els fruits recol¿lectats a final de temporada van tenir major activitat antioxidant i contingut en
Sanchís Soler, E. (2016). Effect of processing on the physicochemical, sensory, nutritional and microbiological quality of fresh-cut 'Rojo Brillante' persimmon [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62588
TESIS

This thesis examines the utility of the Rényi entropy (RE), a measure of the complexity of probability density functions, as a tool for finding physically meaningful patterns in geophysical data. Initially, the RE is applied to observational data of long-lived atmospheric tracers in order to analyse the dynamics of stratospheric transitions regions associated with barriers to horizontal mixing. Its wider applicability is investigated by testing the RE as a method for highlighting internal boundaries in snow and ice from ground penetrating radar (GPR) recordings. High-resolution 500 MHz GPR soundings of dry snow were acquired at several sites near Scott Base, Antarctica, in 2008 and 2009, with the aim of using the RE to facilitate the identification and tracking of subsurface layers to extrapolate point measurements of accumulation from snow pits and firn cores to larger areas. The atmospheric analysis focuses on applying the RE to observational tracer data from the EOS-MLS satellite instrument. Nitrous oxide (N2O) is shown to exhibit subtropical RE maxima in both hemispheres. These peaks are a measure of the tracer gradients that mark the transition between the tropics and the mid-latitudes in the stratosphere, also referred to as the edges of the tropical pipe. The RE maxima are shown to be located closer to the equator in winter than in summer. This agrees well with the expected behaviour of the tropical pipe edges and is similar to results reported by other studies. Compared to other stratospheric mixing metrics, the RE has the advantage that it is easy to calculate as it does not, for example, require conversion to equivalent latitude and does not rely on dynamical information such as wind fields. The RE analysis also reveals occasional sudden poleward shifts of the southern hemisphere tropical pipe edge during austral winter which are accompanied by increased mid-latitude N2O levels. These events are investigated in more detail by creating daily high-resolution N2O maps using a two-dimensional trajectory model and MERRA reanalysis winds to advect N2O observations forwards and backwards in time on isentropic surfaces. With the aid of this ‘domain filling’ technique it is illustrated that the increase in southern hemisphere mid-latitude N2O during austral winter is probably the result of the cumulative effect of several large-scale, episodic leaks of N2O-rich air from the tropical pipe. A comparison with the global distribution of potential vorticity strongly suggests that irreversible mixing related to planetary wave breaking is the cause of the leak events. Between 2004 and 2011 the large-scale leaks are shown to occur approximately every second year and a connection to the equatorial quasi-biennial oscillation is found to be likely, though this cannot be established conclusively due to the relatively short data set. Identification and tracking of subsurface boundaries, such as ice layers in snow or the bedrock of a glacier, is the focus of the cryospheric part of this project. The utility of the RE for detecting amplitude gradients associated with reflections in GPR recordings is initially tested on a 25 MHz sounding of an Antarctic glacier. The results show distinct regions of increased RE values that allow identification of the glacial bedrock along large parts of the profile. Due to the low computational requirements, the RE is found to be an effective pseudo gain function for initial analysis of GPR data in the field. While other gain functions often have to be tuned to give a good contrast between reflections and background noise over the whole vertical range of a profile, the RE tends to assign all detectable amplitude gradients a similar (high) value, resulting in a clear contrast between reflections and background scattering. Additionally, theoretical considerations allow the definition of a ‘standard’ data window size with which the RE can be applied to recordings made by most pulsed GPR systems and centre frequencies. This is confirmed by tests with higher frequency recordings (50 and 500 MHz) acquired on the McMurdo Ice Shelf. However, these also reveal that the RE processing is less reliable for identifying more closely spaced reflections from internal layers in dry snow. In order to complete the intended high-resolution analysis of accumulation patterns by tracking internal snow layers in the 500 MHz data from two test sites, a different processing approach is developed. Using an estimate of the emitted waveform from direct measurement, deterministic deconvolution via the Fourier domain is applied to the high-resolution GPR data. This reveals unambiguous reflection horizons which can be observed in repeat measurements made one year apart. Point measurements of average accumulation from snow pits and firn cores are extrapolated to larger areas by identifying and tracking a dateable dust layer horizon in the radargrams. Furthermore, it is shown that annual compaction rates of snow can be estimated by tracking several internal reflection horizons along the deconvolved radar profiles and calculating the average change in separation of horizon pairs from one year to the next. The technique is complementary to point measurements from other studies and the derived compaction rates agree well with published values and theoretical estimates.