Academic literature on the topic 'Humidity of the process gass'
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Journal articles on the topic "Humidity of the process gass"
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Drandova, Gergana I. "Temperature, humidity, and bias acceleration model for a GaAs pHEMT process." Microelectronics Reliability 55, no. 12 (December 2015): 2511–15. http://dx.doi.org/10.1016/j.microrel.2015.09.027.
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Siswoyo, Siswoyo, Trio F. Nugroho, Zulfikar Zulfikar, and Agus Subekti. "ELECTROPOLYMERISATION AND CHARACTERISATION OF DOPED-POLYPYRROLE AS HUMIDITY SENSOR." Indonesian Journal of Chemistry 6, no. 2 (June 14, 2010): 189–94. http://dx.doi.org/10.22146/ijc.21759.
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A new type of sensing materials for humidity measurement has been developed based on conducting polymer polypyrrole synthesised from pyrrole by adding some dopant compounds, bromide and chloride, it is prepared by potentiodynamic-electropolymerisation technique. Variation of dopant types and concentration has been carried out in order to investigate the effect of this variation to the change of polymeric conductivity when interacting with water vapour. Polypyrrole-Cl (Ppy-Cl) and polypyrrole-Br (Ppy-Br) exhibit a good principal characteristic as sensor candidate namely responding proportionally to humidly variation ranging 30% - 90% relative humidity. Characterisation test for the sensor candidates has been carried out for evaluating their linearity respond toward humidity, their stability in certain period and their reproducibility in some tests. The results show that Ppy-Cl and Ppy-Br showing good linearity respond with R value in a range of 0.95 - 0.99. Their reproducibility and sensitivity were relatively good, however their respond stability were only last in few days. The stability probably is related to the stability of resulted polymeric structure that very affected by synthesis process and dopant used. It is necessary to extend the use of other dopant materials and changing the synthesis process in order to improve sensor stability. In other hand it is also necessary to characterise other performance characteristic of the sensor namely response time, and interference effect of some volatile chemicals and other gases. Keywords: polypyrrole, potentiodynamic, electropolymerisation, humidity sensor and conducting polymer
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Yan, Xueru, Alexandre Favard, Stéphane Anguille, Marc Bendahan, and Philippe Moulin. "Effects of Operating Parameters on Ionic Liquid Membrane to Remove Humidity in a Green Continuous Process." Membranes 9, no. 5 (May 24, 2019): 65. http://dx.doi.org/10.3390/membranes9050065.
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Membrane processes are promising methods to separate gases from feed streams without phase changing. A hybrid process, the combination of ionic liquids with a ceramic membrane (ILM), has been developed for humidity removal in a green continuous process. This new concept provides a more efficient and available ionic liquid (IL)-based membrane regeneration process, which just switches the moist feed stream to dry air. Furthermore, the ILM presents high stability and mechanical resistance during long-time operation. In addition, the influences of several operating parameters, including flow rate, temperature, absolute pressure, and feed concentration on process efficiency were investigated. The lower inlet flow rate was found to be favorable for drying humid air. Moreover, when the pressure increased, the mass of absorbed water was increased, while the feed concentration had no significant effects on the membrane separation performance. However, the operating temperature had a great effect on humidity removal. It is necessary to note that the processes at room temperature can limit the energy consumption. The absorbing process of ILM remained efficient after several absorption desorption cycles. Therefore, the new ILM hybrid process that has been developed has great potential for consecutive humidity removal processes.
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Janicka, Ewa, Michal Mielniczek, Lukasz Gawel, and Kazimierz Darowicki. "Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements." Energies 14, no. 11 (May 24, 2021): 3038. http://dx.doi.org/10.3390/en14113038.
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Water management is a key factor affecting the efficiency of proton exchange membrane fuel cells (PEMFCs). The currently used monitoring methods of PEMFCs provide limited information about which processes or components that humidity has a significant impact upon. Herein, we propose the use of a novel approach of impedance measurements using a multi-sinusoidal perturbation signal, which enables impedance measurements under dynamic operating conditions. The manuscript presents the effect of the relative humidity (RH) of the reactants on the instantaneous impedance of the middle cell in the PEMFC stack as a function of the current load. Analysis of changes in the values of equivalent circuit elements was carried out to determine which process determines the stack’s performance depending on the load range of the fuel cell during operation. Comprehensive impedance analysis showed that to ensure optimal cell operation, the humidity of the reactants should be adjusted depending on the load level. The results showed that at low-current loads, the humidity of gases should be at least 50%, while at high-current loads, the cell should operate optimally at a gas humidity of 30% or lower. The presented methodology provides an important tool for optimizing and monitoring the operation of fuel cells.
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Miri Adigozalova, Dursun, and Turay Fakhraddin Isgandarov. "Optimum silkworm feeding rates." NATURE AND SCIENCE 02, no. 03 (May 8, 2020): 30–34. http://dx.doi.org/10.36719/2707-1146/03/30-34.
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The article notes that non-regulation of temperature and relative humidity in silkworm feeds can lead to malnutrition, digestive disorders, edema and inhibition of growth, as well as to a number of diseases. To avoid this, the heat in the greenhouse should be adjusted according to optimal temperature norms. In the first years I-II-III the average temperature in the greenhouse is 25.5° C, in IV-23.5 ° C, in V-24 ° C. Normal relative humidity should be adjusted during feeding in the greenhouse to avoid the above. In the first I-II-III years it is normal when the relative humidity in the greenhouse is 70%, in the IV age 70% and in the V age 65%. If the temperature and humidity are not in the normal range during the cocoon transition process, the turnover breaks, resulting in loss of product. The normal temperature during the cocoon transition process should be 23.50 C and the relative humidity should be 65%. One of the main factors affecting the yield of silkworms is the correct regulation of field norms at different ages. If an age-appropriate area is not created, the silkworm becomes ill, leading to malnutrition. Normal field units (per 1 box of silkworms) were assigned at different ages: I year-2.5 m2, II year 6-7 m2, III year 15-17 m2, IV year 30-35 m2, V year 55-60 m2. The amount of greenhouse gases, the flow rate and the volume of air should be normal during feeding in the greenhouse. Therefore, the greenhouse air must be changed frequently during feeding. The presence of toxic gases, such as ammonia, hydrogen sulfide, is unacceptable. The speed or lack of airflow is harmful to the silkworm. During feeding, the airflow rate is 0.1 m/s. When feeding of silkworms is applying in accordance with established norms, biological and technological indicators of silkworms are high. Key words: Bombyxi mori, silk, temperature, relative humidity
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Fitriyah, Qoriatul, Muhammad Prihadi Eko Wahyudi, and Markus Grömping. "Calibration of Relative Humidity with Artificial Mass Method in Biogas Plant." JURNAL INTEGRASI 13, no. 1 (April 30, 2021): 63–67. http://dx.doi.org/10.30871/ji.v13i1.2025.
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Biogas plant needs to be given specific amount of relative humidity setting in order to make it work optimally. It is one major factors of gas waste adsorption through final process of activated carbon in biogas plant, especially for hydrogen sulfide. Hydrogen sulfide is a side gas appeared in biogas plant which has to be removed by various processes, including the presence of activated carbon filter that usually appeared on last stage of biomass filtration process which is poisonous and corrosive to the metal parts. Today, air humidity gauges have been found quite a lot on the market. However, how accurate the device is, needs to be further proven in the laboratory, especially when the gauges have to face corrosive gases such as this H2S. Therefore, calibration for cheap and efficient relative humidity measurement is very necessary. The method will use comparison between RH reading and RH calculation based on parameters of plant settings in the form of gas composition mixture, flow duration, pressure, volumetric flow rate, and temperature. This paper will discuss how to calculate and measure calibration for relative humidity that is practical, simple and does not cost much so that it is expected to be used for low-funding research in biogas plant.
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Sychevskii, V. A. "Modeling of the technological process of convective drying of lumber." Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 63, no. 4 (January 12, 2019): 424–34. http://dx.doi.org/10.29235/1561-8358-2018-63-4-424-434.
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A calculation of the technological process of lumber drying in convection drying chamber of periodic action is presented. For this purpose, a three-dimensional geometric model of a drying chamber with a lumber pile is developed. A physico-mathematical model describing the processes of heat and mass transfer both in the drying agent and in the stack is presented. The three-dimensional geometry of the problem was taken into account by using the Ansys Fluent package. The process of mass transfer in wood was described on the basis of User-Defined Function and User-Defined Scalar. The result of calculation of a specific technological regime of drying of stack from pine sawn timber is given, which allowed finding detailed spatial distributions and temporary changes of the temperature and humidity fields for the drying agent and wood. On their basis, graphs of the time variation of the mean values are plotted. The nonlinearity and interrelationship of the processes of heat and mass transfer in a convective drying chamber leads to unsteadiness of the drying process. So, during the warm-up stage, it is not possible to avoid moisture removal from the lumber. At the drying stages, the unsteadiness leads to an oscillatory character of changes of the temperature, the mass fraction of vapour and the relative humidity of air in the gaps between the wood boards at the intensive heat input. Therefore, it is necessary to take additional procedures to keep the drying agent parameters constant at the drying stages. The obtained results can be used for the design of drying chambers and the development of drying regimes of lumber based on the mathematical modeling and computational experiment.
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Darie, Marius, Dănuţ-Nicolae Grecea, and Cosmin-Ioan Colda. "Threshold alarm tests of electrical devices for the detection of combustible gases in domestic premises." MATEC Web of Conferences 305 (2020): 00085. http://dx.doi.org/10.1051/matecconf/202030500085.
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The paper describes a measuring system for testing of the combustible gases detectors used in domestic premises. The general requirements are presented for the electrical equipment used in gas detection. A theoretic analytical model is proposed for measuring the test gas concentration and assessing the influence of air humidity. The requirements considered for designing the measuring system are presented for the experimental setup. The presented assembly structure was tested and the results were presented. Consequently, the measurement uncertainty was determined. It was found that the use of a high precision oxygen analyzer is reliable in the process of calibration testing. It was also found that the variation of relative humidity during the measurement influences the gas concentration measured.
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Shikina, N. V., S. R. Khairulin, N. A. Rudina, T. N. Teryaeva, E. S. Mikhaylova, and Z. R. Ismagilov. "Investigation of the Sorption Properties of Ore Materials for the Removal of Sulfur Dioxide from Exhaust Flue Gases of Power Plants." Eurasian Chemico-Technological Journal 17, no. 2 (October 22, 2015): 137. http://dx.doi.org/10.18321/ectj204.
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The prospects of using a natural material – ferromanganese nodules (FMN) from<br />the Gulf of Finland – as the SO2 adsorbent are discussed. The starting material was<br />studied as pellets and powder using X-ray fluorescence spectroscopy, XRD, BET,<br />and mechanical strength analysis; dependences of physicochemical parameters of<br />the material on heat treatment at 100-1000 ºC were found. FMN samples were tested in the process of SO2 sorption. The sorptive capacity of FMN samples for SO2 was found to increase with humidity of adsorbents; FMN samples with a humidity above 40% were shown to be promising for the removal of sulfur dioxide from gases.
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Huber, Christof, Maria Pilar Pina, Juan José Morales, and Alexandre Mehdaoui. "A Multiparameter Gas-Monitoring System Combining Functionalized and Non-Functionalized Microcantilevers." Micromachines 11, no. 3 (March 10, 2020): 283. http://dx.doi.org/10.3390/mi11030283.
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The aim of the study is to develop a compact, robust and maintenance free gas concentration and humidity monitoring system for industrial use in the field of inert process gases. Our multiparameter gas-monitoring system prototype allows the simultaneous measurement of the fluid physical properties (density, viscosity) and water vapor content (at ppm level) under varying process conditions. This approach is enabled by the combination of functionalized and non-functionalized resonating microcantilevers in a single sensing platform. Density and viscosity measuring performance is evaluated over a wide range of gases, temperatures and pressures with non-functionalized microcantilevers. For the humidity measurement, microporous Y-type zeolite and mesoporous silica MCM48 are evaluated as sensing materials. An easily scalable functionalization method to high-throughput production is herein adopted. Experimental results with functionalized microcantilevers exposed to water vapor (at ppm level) indicate that frequency changes cannot be attributed to a mass effect alone, but also stiffness effects dependent on adsorption of water and working temperature must be considered. To support this hypothesis, the mechanical response of such microcantilevers has been modelled considering both effects and the simulated results validated by comparison against experimental data.
Dissertations / Theses on the topic "Humidity of the process gass"
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Slámová, Jitka. "Studium sterilizačních účinků dielektrického bariérového výboje." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-233367.
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The overall goal of the presented dissertation thesis was to study the sterilization efficiency of dielectric barrier discharge operated at atmospheric pressure. The fungi Aspergillus niger, gram-positive bacteria Bacillus subtilis and in some experiments also gram-negative bacteria Escherichia coli were used as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. The samples of microorganism were placed on paper Whatman 1 or PET foil and exposed to plasma. The plasma was generated in argon, nitrogen, synthetic dry/humid air with frequency up to 10 kHz and plasma power density in the range of 1,2-2,9 W/cm3 (according to the process gas). The influence of process gas, plasma power density, plasma exposition time, type of microorganism and material of the substrate on the sterilization effect of dielectric barrier discharge was evaluated. Furthermore the contribution of each single mechanism (UV radiation, temperature and reactive species) to the sterilization effect of plasma and influence of gas humidity was evaluated. The DBD was analysed by means of optical emission spectroscopy, thermocouple was used to measure temperature during a sterilization process. In order to verify the mechanical damage of the microbial cell or the substrates during the plasma process the samples were studied by scanning electron microscopy. Generally, on the basis of experimental results, at increasing treatment times, the remaining number of spores (CFU) decreased. Similarly at increasing the plasma power input, the sterilization rate increased. When sterilising the spores of A. niger in plasma using different process gasses, the efficiency of plasma sterilization decreased as follows: argon, humid synthetic air, nitrogen and dry synthetic air. The results observed in argon plasma using different microorganism demonstrated that the sensitivity of vegetative cells resp. spores to DBD decreased as follows: A. niger spores, B. subtilis vegetative cells, E. coli vegetative cells and B. subtilis spores. Simultaneously results observed for sterilization of spores and vegetative cells of B. subtilis and A. niger demonstrated that the spores are generally more resistant to plasma than are the corresponding vegetative cells. Combining the results of contribution of each single mechanism, optical emission spectroscopy and inactivation characteristic it was found out that the reactive species significantly contribute to the plasma sterilization in all process gasses. Furthermore the inactivation process can be partly assisted by UV radiation and also the temperature can contribute in limited extent to inactivation process in some gasses. The contribution of UV radiation to the plasma sterilization decreased as follows: nitrogen, argon, dry syntetic air and humid syntetic air. Moreover it was found out that the contribution of each single mechanism can be species dependent, this is due to the different response of microorganism to the unfavorable external conditions. SEM analysis of the substrates prooved the etching actions of the plasma generated in all process gasses on the surface of the PET foil. The several minute plasma exposition of the PET foil resulted in the occurence of the „hole corrosion“ on the PET surface. Contrary to these there were no visible changes observed in the paper structure.
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Yan, Xueru. "Development of a hybrid process, Membrane-Ionic Liquid (ILM), for gas treatment Ionic liquids combined wtih membrane separation processes : A review." Thesis, Ecole centrale de Marseille, 2020. http://www.theses.fr/2020ECDM0009.
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L'élimination des polluants d'un mélange gazeux est un enjeu majeur en termes de réduction de l'impact environnemental de nombreux procédés industriels. Les liquides ioniques sont des solvants de remplacement prometteurs pour les composés organiques traditionnels utilisés dans la séparation sélective en raison de leur pression de vapeur négligeable et de leurs propriétés chimico-physiques concevables. Dans cette étude, un nouveau concept, la combinaison des IL et d'une membrane céramique tubulaire (ILM), a été développé dans le but de séparer les gaz ou les liquides des flux d'alimentation. Par rapport aux procédés classiques d'élimination des gaz ou des liquides, les ILM offrent une grande stabilité et une résistance mécanique élevée pendant une longue période de fonctionnement. Dans le cas des traitements de gaz, l'élimination de l'humidité pour protéger le capteur de gaz et le traitement du gaz industriel contenant du toluène sont les deux parties développées dans ce manuscrit. Les effets de plusieurs paramètres de fonctionnement, notamment le débit de gaz, la température, la pression, la concentration d'alimentation, la surface effective de la membrane (longueur de la membrane de support) et la position des canaux de gaz, ont été étudiés à la fois sur l'élimination de l'humidité et du toluène (vapeur). En outre, un modèle mathématique en deux étapes a été utilisé pour simuler les résultats expérimentaux et évaluer la performance de séparation des MIL dans les conditions de fonctionnement proposées. Selon les résultats expérimentaux et simulés, les ILM présentaient une capacité d'absorption relativement élevée de l'humidité et du toluène. Ce nouveau procédé ILM sera le procédé vert dominant pour la séparation des polluants gazeux ou liquidesThe removal of pollutants from a gas mixture is a major issue in terms of minimizing the environment impact of numerous industrial processes. Ionic liquids are promising alternative solvents for traditional organic compounds using in selective separation due to their negligible vapor pressure and designable chemic-physical properties. In this study, a new concept, combination of ILs and a tubular ceramic membrane (ILM), has been developed with the aim of gas or liquid separation from feed streams. Comparing to conventional gas or liquid removal processes, ILMs provide high stability and mechanical resistance during long-time operation. Moreover, specific properties of ILs ensure selectivity and absorption capacity of ILMs. In the case of gas treatments, removal of humidity to protect gas sensor and treatment of industrial gas containing toluene are the two parts developed in this manuscript. Effects of several operating parameters, including gas flow rate, temperature, pressure, feed concentration, effective surface area of membrane (length of the support membrane) and position of gas channels, were investigated both on humidity and toluene (vapor) removal. In addition, a two-step model was used to simulate experimental results and evaluate the separation performance of ILMs. According to both experimental and simulated results, ILMs exhibited relative high absorption capacity of humidity and toluene. This new ILM process will be the dominating green processes for gas or liquid pollutants separation
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Hauser, Gerd. "Analyse von Schweißnahtunregelmäßigkeiten beim WIG-Orbitalschweißen von vollaustenitischen Stahlrohren." Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-83466.
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Die Bildung von Anlauffarben durch molekularen Sauerstoff im Wurzelschutzgas ist bereits gut erforscht. Weitere Sauerstoffquellen für die Bildung von Anlauffarben sind Feuchte und CO2. Besonders Feuchte ist in diesem Zusammenhang kritisch, da sie sich wesentlich langsamer mit den etablierten Mitteln entfernen lässt. Im Rahmen dieser Arbeit konnte für durch Feuchte verursachte Anlauffarben im Wurzelschutzgas ein Grenzwert von 300 ppm bei 23 °C ermittelt werden. Die Farbausprägung der durch Feuchte verursachten Anlauffarben tendiert besonders bei schwachen bis mittleren Ausprägungen (450-800 ppm) stärker ins Bräunliche als die durch molekularen Sauerstoff verursachten Anlauffarben. Mit Hilfe des an der TU Dresden entwickelten Algorithmus für die Auswahl von Gaskomponenten für Prozessgase, wurde für das gepulste WIG-Orbitalschweißverfahren von austenitischen CrNi-Stahlrohren das Gasgemisch Ar/He/H2 20/70/10 ausgewählt. Gegenüber dem ursprünglich als Prozessgas verwendeten Argon und einem Ar/He 70/30 Gemisch, zeigte sich eine mögliche Steigerung der Vorschubgeschwindigkeit um den Faktor 3,5. Bei Fragen und Anmerkungen zur Arbeit sowie beim Verfassen einer weiterführenden Arbeit bitte Kontakt mit dem Autor aufnehmen (gerd.hauser@gmx.de). Dieser ist an einer Weiterführung des Themas sowie einer unabhängigen Überprüfung der Messwerte sehr interessiertThe formation of annealing colors by molecular oxygen in the backing gas is already well understood. Other sources of oxygen for the formation of annealing colors are humidity and CO2. Moisture is especially critical in this context, since they can be removed much more slowly with the established agents. As part of this work can be set a limit for annealing colors (caused by moisture in the root protection gas) of 300 ppm moisture with a environment temparatur of 23 ° C. The annealing colors caused by humidity tends especially in low to moderate conzentrtions (450-800 ppm) mor to a brownish than the annealing colors caused by molecular oxygen. Using the algorithm developed at the TU Dresden for the selection of gas components for process gases,the gas mixture Ar/He/H2 20/70/10 was chosen for the pulsed TIG orbital welding of austenitic stainless steel tubes. Compared to the originally used process gas argon and Ar/He-mixture 70/30, showed the Ar/He/H2 mixtur a possible increase in feed rate by a factor of 3.5
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Xu, Yichi. "EFFICIENCY OF COATING PROCESS AND REAL-TIME VOLATILE RELEASE IN TOMATILLO AND TOMATO." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259639281.
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Kahandagamage, Gayan. "Analysis of the effect of charge air temperature and humidity on the combustion process of diesel engines at Heladhanavi Power Plant, Puttalam, Sri Lanka." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166176.
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Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time. Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value.På uppdrag av Högskolan i Gävle
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Phan, Ngoc Anh. "Simulation of time-dependent crack propagation in a quasi-brittle material under relative humidity variations based on cohesive zone approach : application to wood." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0008/document.
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Cette thèse est consacrée à la simulation du comportement à la rupture de bois sous des chargements à long terme et sous des conditions d'Humidité Relatives (HR) de l'air variables. Il est connu que le bois est un matériau fortement hygroscopique, ses propriétés mécaniques et de rupture sont en effet très dépendantes de sa teneur en eau. En outre, la stabilité d'une fissure existante dans un élément structural peut être fortement influencée parles variations, en particulier brusques, d'humidité relative qui peut conduire à la rupture inattendue de l'élément.L'approche thermodynamique proposée intègre l'effet de mécanosorption dans l'expression analytique de la déformation, en découplant les déformations mécaniques et celles dues au comportement mécanosorptif du matériau. En outre, la rupture quasi-fragile du matériau boisest traduite par un modèle de zone cohésive dont les paramètres de cohésion sont fonctions de la teneur en eau afin de simuler l’effet de l'humidité sur les propriétés de rupture. Sur cette base, une formulation incrémentale permet l'intégration de l'effet des variations soudaines d’humidité relative (autrement dit, le choc hydrique) sur la zone d’élaboration(zone cohésive) en introduisant un champ de contraintes supplémentaires le long de cette zone. Fonction de la variation de HR, ce champ de contraintes supplémentaires dépend de l'état de contrainte et de l'ouverture de la fissure le long de la zone cohésive, mais également de l'humidité en pointe de fissure (matériau non endommagé). Dans l'analyse par éléments finis, un opérateur tangent algorithmique est utilisé pour résoudre le problème non linéaire en combinant le modèle de mécanosorption et le modèle de zone cohésive et en intégrant l'effet du choc hydrique.La simulation du comportement d'une éprouvette entaillée soumise à un chargement constant et à des variations cycliques de HR montre un fort couplage entre le comportement mécanosorptif et l'effet du choc hydrique HR sur la zone d’élaboration. Ce couplage entraîne une augmentation de la propagation des fissures et conduit à une fissuration plus précoce par rapport à celle obtenue à partir du modèle de mécanosorption seul ou à partir du modèle de zone cohésive en intégrant l'effet des variations soudaines de HR. En outre, le couplage entre le modèle mécanosorptif et le modèle de zone cohésive en intégrant l'effet du chochydrique montre l'intérêt d'une telle approche numérique pour décrire le comportement complexe des éléments de charpente en bois soumis à des conditions climatiques variables,comportement qui ne peut être prédit par une simple superposition des deux modélisationsThis thesis is dedicated to the simulation of the fracture behavior of wood under long-termloading and variable relative humidity conditions. Indeed, wood is well-known to be a highlyhygroscopic material in so far as its mechanical and fracture properties are very dependenton moisture. Moreover, the stability of an existent crack in a structural element can bestrongly affected by the sudden variations of relative humidity (RH) and can lead tounexpected failure of the element.The thermodynamic approach proposed in this thesis includes the mechano-sorptive effect inthe analytical expression of the deformation, by operating a decoupling of the strain in amechanical part and a mechano-sorptive part in material. Moreover, the quasi-brittle fractureof wood is here simulated from a cohesive zone model whose cohesive parameters arefunctions of the moisture in order to mimic the moisture-dependent character of the fractureproperties. On this basis, an increment formulation allows the integration of the effect ofsudden RH variations on the fracture process zone (cohesive zone) by introducing anadditional stress field along this zone. As a function of the RH variation, this additional stressfield depends on not only the stress state and the crack opening along the cohesive zone butalso the material moisture ahead of the zone (undamaged material). In the finite elementanalysis, an algorithmic tangent operator is used to solve the non-linear problem combiningmechano-sorptive model and cohesive zone model including the effect of sudden RHvariations.The simulation of a notched structural element submitted to a constant load and cyclic RHvariations exhibits a strong coupling between the mechano-sorptive behavior and the effectof the RH variations on the fracture process zone (FPZ). This coupling results in an increaseof the crack propagation kinetic and leads to a precocious failure compared to those obtainedfrom the mechano-sorptive model or from the effect of sudden RH variations on the FPZ.Moreover, the coupling between the mechano-sorptive model and the effect of sudden RHvariations on the FPZ which cannot be predicted by a simple superposition of both effects,showing the interest of such a numerical approach in order to describe the complex behaviorof wood structural elements submitted to variable climatic conditions
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Veselá, Lucie. "Teplotně vlhkostní namáhaní stěny dřevostavby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372117.
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The diploma thesis deals with the thermal-humidity stress of the wooden wall. The work is focused on the connection of the wall to the base structure of the building. Three details were chosen. The work was focused on detail with the most common structure of an external wall used in the Czech Republic on the composition with a supporting structure made of KVH columns, which are filled with mineral insulation. This construction is covered with plate elements. The insulation from the exterior is made of ETICS with expanded polystyrene thermal insulation. This detail was assessed in the software. To compare the results calculated by real-time software, an experimental model was made, which was subjected to experimental measurements. Part of the diploma thesis is a comparison of detail stress under different boundary design conditions, with or without anchoring.
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Newman, John Andrew. "The Effects of Load Ratio on Threshold Fatigue Crack Growth of Aluminum Alloys." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29418.
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The integrity of nearly all engineering structures are threatened by the presence of cracks. Structural failure occurs if a crack larger than a critical size exists. Although most well designed structures initially contain no critical cracks, subcritical cracks can grow to failure under fatigue loading, called fatigue crack growth (FCG). Because it is impossible or impractical to prevent subcritical crack growth in most applications, a damage tolerant design philosophy was developed for crack sensitive structures. Design engineers have taken advantage of the FCG threshold concept to design for long fatigue lives. FCG threshold (DKth) is a value of DK (crack-tip loading), below which no significant FCG occurs. Cracks are tolerated if DK is less than DKth. However, FCG threshold is not constant. Many variables influence DKth including microstructure, environment, and load ratio. The current research focuses on load ratio effects on DKth and threshold FCG. Two categories of load ratio effects are studied here: extrinsic and intrinsic. Extrinsic load ratio effects operate in the crack wake and include fatigue crack closure mechanisms. Intrinsic load ratio effects operate in the crack-tip process zone and include microcracking and void production. To gain a better understanding of threshold FCG load ratio effects (1) a fatigue crack closure model is developed to consider the most likely closure mechanisms at threshold, simultaneously, and (2) intrinsic load ratio mechanisms are identified and modeled.
An analytical fatigue crack closure model is developed that includes the three closure mechanisms considered most important at threshold (PICC, RICC, and OICC). Crack meandering and a limited amount of mixed-mode loading are also considered. The rough crack geometry, approximated as a two-dimensional sawtooth wave, results in a mixed-mode crack-tip stress state. Dislocation and continuum mechanics concepts are used to determine mixed-mode crack face displacements. Plasticity induced crack closure is included by modifying an existing analytical model, and an oxide layer in the crack mouth is modeled as a uniform layer. Finite element results were used to verify the analytical solutions for crack-tip stress intensity factor and crack face displacements. These results indicate that closure for rough cracks can occur at two locations: (1) at the crack-tip, and (2) at the asperity nearest the crack-tip. Both tip contact and asperity contact must be considered for rough cracks. Tip contact is more likely for high Kmax levels, thick oxide layers, and shallow asperity angles, a. Model results indicate that closure mechanisms combine in a synergistic manner. That is, when multiple closure mechanisms are active, the total closure level is greater than the sum of individual mechanisms acting alone. To better understand fatigue crack closure where multiple closure mechanisms are active (i.e. FCG threshold), these interactions must be considered. Model results are well supported by experimental data over a wide range of DK, including FCG threshold.
Closure-free load ratio effects were studied for aluminum alloys 2024, 7050, and 8009. Alloys 7050 and 8009 were selected because load ratio effects at FCG threshold are not entirely explained by fatigue crack closure. It is believed that closure-free load ratio mechanisms occur in these alloys. Aluminum alloy 2024 was selected for study because it is relatively well behaved, meandering most load ratio effects are explained by fatigue crack closure. A series of constant Kmax threshold tests on aluminum alloys were conducted to eliminate fatigue crack closure at threshold. Even in the absence of fatigue crack closure load ratio (Kmax) effects persist, and are correlated with increased crack-tip damage (i.e. voids) seen on the fatigue crack surfaces. Accelerated FCG was observed during constant Kmax threshold testing of 8009 aluminum. A distinct transition is seen the FCG data and is correlated with a dramatic increase in void production seen along the crack faces. Void production in 8009 aluminum is limited to the specimen interior (plane-strain conditions), promoting crack tunneling. At higher values of Kmax (+_ 22.0 MPaà m), where plane-stress conditions dominate, a transition to slant cracking occurs at threshold. The transition to slant cracking produces an apparent increase in FCG rate with decreasing DK. This unstable threshold behavior is related to constraint conditions. Finally, a model is developed to predict the accelerated FCG rates, at higher Kmax levels, in terms of crack-tip damage.
The effect of humidity (in laboratory air) on threshold FCG was studied to ensure that environmental effects at threshold were separated from load ratio effects. Although changes in humidity were shown to strongly affect threshold FCG rates, this influence was small for ambient humidity levels (relative humidity between 30% and 70%). Transient FCG behavior, following an abrupt change in humidity level, indicated environmental damage accumulated in the crack-tip monotonic plastic zone. Previous research implies that hydrogen (a component of water vapor) is the likely cause of this environmental damage. Analysis suggests that bulk diffusion is not a likely hydrogen transport mechanism in the crack-tip monotonic plastic zone. Rather, dislocation-assisted diffusion is presented as the likely hydrogen transport mechanism.
Finally, the (extrinsic) fatigue crack closure model and the (intrinsic) crack-tip damage model are put in the context of a comprehensive threshold model. The ultimate goal of the comprehensive threshold model is to predict fatigue lives of cyclically loaded engineering components from (small) crack nucleation, through FCG, and including failure. The models developed in this dissertation provide a basis for a more complete evaluation of threshold FCG and fatigue life prediction.
The research described in this dissertation was performed at NASA-Langley Research Center in Hampton, Virginia. Funding was provided through the NASA GSRP program (Graduate Student Researcher Program, grant number NGT-1-52174).Ph. D.
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Shih-Ming, Huang, and 黃士銘. "Improvement of Graphene Oxide Process: Study on Corrosion Resistance and Application of Humidity Sensor." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/f6u5tk.
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碩士中原大學
機械工程研究所
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Graphene oxide (GO) prepared from various modified Hummers method was used as anti-corrosion barrier and humidity sensor. In this study, different manufacturing process and drying method was compared to different material properties. The surface morphology, crystallinity, dispersibility, defect degrees and functional group were observed by using scanning electron microscopy, X-ray diffraction, zeta potential analyzer, RAMAN and FT-IR spectra. The result of material properties showed the oxidation degree difference from manufacture process. Graphene oxide was then deposited on stainless steel substrate by electrophoretic deposition. The graphene oxide film served as a anti-corrosion barrier layer, protecting steel from corrosion media. The high charge transfer impedance of graphene oxide inhibited the occurrence of chemical corrosive reactions. Graphene oxide also had the competitive low price compared to those existing anti-corrosion coating. On the other hand, this study used graphene oxide and quartz crystal microbalance as humidity sensor. Graphene oxide with higher oxidation degrees was full of hydroxyl. It helped capture lots of water molecules that enhance the sensitivity of humidity sensor. The result would be proved by using frequency counter and impedance spectroscopy.
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Lemos, Ana Rita Magalhães Vieira Castro de. "composite hollow fiber membranes for humidity harvesting coating of porous substrates. process development and optimization." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/88355.
Full textBook chapters on the topic "Humidity of the process gass"
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Lys, Stepan, Oksana Yurasova, and Yuriy Vashkurak. "Influence of Humidity of Wood Fuel on the Gasification Process in a Continuous Layer." In Lecture Notes in Civil Engineering, 268–76. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-57340-9_33.
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Behrens, Grit, Johannes Weicht, Klaus Schlender, Florian Fehring, Rouven Dreimann, Michael Meese, Frank Hamelmann, Christoph Thiel, Thorsten Försterling, and Marc Wübbenhorst. "Smart Monitoring System of Air Quality and Wall Humidity Accompanying an Energy Efficient Renovation Process of Apartment Buildings." In Progress in IS, 181–89. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-65687-8_16.
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Emdadul Hoque, Md, and Fazlur Rashid. "Gasification Process Using Downdraft Fixed-Bed Gasifier for Different Feedstock." In Gasification [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96227.
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The use of conventional fuels is decreasing globally due to its limited reserves and negative impact on the environment. The associated cost of conventional fuels is increasing owing to the higher demand for conventional fuels. Hence, utilization methods of biomass to generate energy are of growing interest. Among different biomass feedstocks, rice husks, waste plastics, and sawdust are significantly available in the global environment. The annual generation amount of rice husk is approximately 120 million tons worldwide, with an annual energy generation potential of 109 GJ with a heating value of 15 MJ/kg. The gasification process is assumed to be the most effective biomass conversion method that can generate synthetic gas to operate IC engines, fuel cells, and boilers. Synthetic gas production from biomass using a gasification process is a significant source of future energy. Downdraft fixed-bed gasifiers are considered as a feasible option of biomass conversion in the gasification process. By optimizing the operating conditions of downdraft fixed-bed gasifier, such as reaction zone temperature, combustion zone temperature, intake air temperature, airflow rate, the humidity of intake air, a significant amount of synthetic gas can be produced from rice husks, waste plastic material, and sawdust.
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Oktav Bulut, Meliha, and Ayşen Cire. "A Research on Polyamide6.6/Polyurethane Blends in Finishing Process Which Are Used for Sportswear." In Humidity Sensors [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99820.
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In this work, softeners obtained from various companies were applied to the polyamide6.6/polyurethane fabrics which are used in sportswear industry using impregnation and exhaustion methods; water vapor permeability were determined for humidity control, air permeability and capillarity tests of these fabrics were studied. In addition, the wool hydrolysate obtained from the waste wool was also applied to these fabrics by using exhaustion method and the fabric properties were compared. In order to investigate the washing resistance of the process, experiments were performed with 1% and 3% potassium aluminum sulfate KAl(SO₄)2 and aluminum sulfate Al2(SO4) under the same conditions. The chemical and morphological surface properties of the fabrics were examined by using X-ray photoelectron spectroscopy (XPS). It was observed that the capillarity, water vapor and air permeability, and handle values of fabrics treated with wool hydrolysate were better and more resistant to consecutive washings than the fabrics treated with commercial recipes. Furthermore, this process did not have a side effect on the color difference and whiteness values of the fabrics treated with wool hydrolysate. Thus, an example of sustainable, economical and environmental study was done.
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Chidi, Nosiri, Anyanwu Chukwuma, and Nwaogwugwu Joel. "Impact of Emerging Agricultural Contaminants on Global Warming." In Emerging Contaminants. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94170.
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There are many definitions of emerging contaminants (ECs). They are not usually new chemicals and could be substances that have stayed long in the environment with their presence and importance being recognized now. They may be chemicals or microorganisms which are not usually monitored in the environment but with known or suspected potential to cause ecological damage or adverse human effects. Some natural products and those transformed through biochemical processes from synthetic chemicals may be formed in the environment as ECs. Emerging Agricultural Contaminants are released to the environment or enter indirectly to the soil during the application of manure, fertilizers, biosolids or other solid waste materials. Once they enter the soil, they may be transported by leaching, runoff and drainage processes to water bodies. The extent of the transport is dependent on the persistence of the EC and on how it interacts with soil and air. These ECs contribute to global warming through the emissions of Greenhouse gases. The largest source of GHG emission from Agriculture is Nitrous oxide (N2O) and it accounts for 38% of the total global emission through the process of nitrification and denitrification, anthropogenic activities (use of nitrogen fertilizer, production of nitrogen-fixing crops and forages, retention of crop residues, application of managed livestock manure) which are either through direct additions and/or through indirect additions (atmospheric deposition of applied nitrogen). The natural digestive processes in ruminants otherwise known as enteric fermentation account for the key source of methane production under livestock production hence the second largest source of total agricultural emission with 34% global share and rice cultivation being the third with 11%. The three important greenhouse gases (Methane, Carbon dioxide and Nitrous oxide) are not harmful in naturally occurring quantities for their atmospheric presence helps in sustaining life on the planet when they trap heat energy near the surface of the earth. Concentration of greenhouse gases from both the natural and human factors have been increasing and contributing to Global Warming and Climate Change. Increase in greenhouse gases may cause tremendous changes to our civilization positively or negatively but the total impact is uncertain. Climate change comes as a result of a warming planet which can affect the weather adversely in many ways. So, as climate changes, extreme weather activities release severe threats on human society. Indicators of global warming include sea surface temperature, temperature over land, snow cover on hills, temperature over land and humidity. It is expected that climate change may cause more floods, storms, droughts, heatwaves and other extreme weathers activities. IPCC estimated that temp may rise from 2 to 6°C within 2021. Mitigation of greenhouse effect could be achieved through Biochemical methods on enteric fermentation, development of good environmental policies even Methanotrophs also aid in recycling the atmospheric Methane.
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Dolman, Han. "Biogeochemistry and Climate." In Biogeochemical Cycles and Climate, 29–43. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198779308.003.0003.
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This chapter focuses on tools for climate research: biogeochemical observations and models. It discusses physical climate observations, such as temperature and humidity, and in situ observations of atmospheric composition. Turning these into reliable climate records appears to be non-trivial. The chapter describes how isotopes are used to get insight into biogeochemical processes. A special category of observations is biogeochemical proxy observations, used to gain insight into geological processes when no direct observations are possible. The example of climate proxy observations, such as those obtained via ice cores, is described. Models are increasingly used to gain insight into sensitivity of climate to changes in the forcing. Earth system modelling has become increasingly complex over the last two decades, including often detailed biogeochemical processes in the ocean and on land. The parametrization of these remains an important research subject. Inverse modelling is being used to identify sources and sinks of greenhouse gases.
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Sivagami, Arasu, Michael Angelo Kandavalli, and Bhaskarrao Yakkala. "Design and Evaluation of an Automated Monitoring and Control System for Greenhouse Crop Production." In Next-Generation Greenhouses for Food Security. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97316.
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An embedded system integrated with sensors based on nanomaterial is proposed for closely monitoring and control microclimate parameters 24 hours a day to maximise production over the whole crop growth season by introducing greenhouse for the cultivation of plants or specific plant species. The system will also eliminate errors in human intervention to optimise production of crops. This system consists of sensors and actuators, an Analogue to Digital Converter (ADC) and a Raspberry Pi. The system will determine whether a defined threshold is passed by any climate parameter and systematically changes via the controller. The current work reduces human input through automated irrigation to optimally utilize a scarce resource, namely water. Climatic parameters for plant growth such as, moisture, humidity, temperature, water pressure in drip pipe, soil salinity etc. are monitored and optimized. Furthermore, work was extended to include GSM to control the entire farm remotely. For its success, it is very important to choose a greenhouse location. For instance, the problems are quite different when choosing an adjoining greenhouse, for instance a sunroom or greenhouse. The greenhouse location should be chosen for sunlight, proximity to power and water sources, wind, drain and freeze pockets, and the proximity of the garden and house. The intention behind accomplishment and devise of GSM based Fertigation System is to construct and evaluate the requirement of water in the yield as farming is the major resource of production which habitually depends on the water accessibility. Irrigation of water is usually done by manual method. To ease the work of the farmer GSM based automatic Fertigation (includes chemigation too) system can be implemented so that water wastage can be reduced and also the fertilizer can be added accordingly. Also the Soil Salinity can be checked and reduced if exceeds certain limit. By using GSM, only GSM command via GSM mobile can control the start and stop action of a motor that feeds the field with the water. GSM is used for controlling the entire process and the entire system backbone. It can be used from any distance to control irrigation. The results are assessed by electronic simulator PROTEUS using the desired optimised parameters, the design of this automated greenhouse system with PIC controller. As the inputs to the microcontroller and as an LCD screen record the respective outputs, the model produces a soil moisture sensor, light sensor and temperature sensor. The system performance is accurate and repeatable for measuring and controlling the four parameters that are crucial for plant growth - temperature, humidity, soil moisture and light intensity. With the reduction in electricity consumption, maintenance and complexity, and a flexible and precise environment control form for agriculture, the new system successfully cured quite a couple of defects in existing systems. Nano composite film sensors (Graphene and Graphene mixed in order to optimise the input of fertilisers for chemical composition determination. Using nano technology in agriculture enforces the firm bond between the engineer and farmer. Nano material film-based gas sensors were used to measure the presence of oxygen and CO2.using graphene nano composite sensors integrated into an embedded system, to detect the presence and levels of gases. Improve crop growth with combined red and blue light for lighting under the leavened and solar-powered LED lighting modules. This was achieved by graph/solar cells. The light was measured at the photosynthesis flux (PPFD) of 165 μmol m-2 s-1 by 10 cm of its LED module. LED lights were provided between 4:00 a.m. and 4:00 p.m. in the daytime treatments and night treatments from 10 to 10 hours. The use of the nighttime interlumination of LEDs was also economical than the interlumination of charts. Thus, nightlighting LEDs can effectively improve plant growth and output with less energy than the summer and winter times. Solar panels are best functioning during times of strong sunlight today, but begin to wan when they become too hot and cloudy. By allowing Solar Panels to produce electricity during harsh weather conditions and increase efficiency, a breakthrough in graphene-based solar panels can change everything. Ultimately with a fully autonomous system, agricultural productivity and efficiency, the length of the growing season, energy consumption and water consumption were recorded and monitored by exporting the data over GSM environment. With the steady decrease in the cost of high-performing hardware and software, the increased acceptance of self-employed farming systems, and the emerging agricultural system industry, the results will be reliable control systems covering various aspects of quality and production quantity.
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R J, Vijaya Saraswathi, Sukambika S, Wilcy Theresa F, Ishwarya M, and Srinithi T. "Modeling and Design of a Controller for a Dehumidifier." In Intelligent Systems and Computer Technology. IOS Press, 2020. http://dx.doi.org/10.3233/apc200129.
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Many industries like pharmaceutics, plastics, food and confectionery, tobacco and cold storage, maintaining the humidity at the desired level is very important. The aim of this paper is to process the model and to design a controller for a dehumidifier to control the humidity at the desired set point. The air is humidified using a humidity chamber. This humid air which is the primary air is mixed with secondary air from the compressor and sent to the dehumidifier. The dehumidifier used here is a centrifugal separator. The humidity of the dehumidified air is measured using a sensor. The output signal of the sensor is compared to the set point. If the output measured exceeds the set point, accordingly the flow rate of the secondary air to the dehumidifier is varied until it reaches the desired set point .The model of the process is identified from the response of the process to the input signals. The controller is designed for the model obtained and the performance of the controller based on the time domain specification is compared.
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Akash and Navneet. "Impact of Climatic Changes on Earth's Survival." In Advances in Environmental Engineering and Green Technologies, 160–82. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7387-6.ch009.
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Every species' survival on earth is dependent on each other for their demand and dependent on the environment and various other sources. These resources include fresh food, clean drinking water, timber for construction, natural gas and coal for industries, fibers for clothing. All the human activity affects the environment severely in different ways. The biggest threats to the environment are climatic changes. Climate is an important factor that affects all survival on earth. The different pollutants, transport, dispersion, chemical transformation, as well as the deposition can be affected by meteorological variable such as humidity, wind, temperature. Climatic changes are expected to worsen the quality of air and water by changing the atmospheric processes and chemistry. Not only human beings but every aspect of the ecosystem is affected due to the changing climate. This chapter will explore the impacts of climatic changes on biodiversity by various activities of humans. Additionally, it will sketch how the impacts can be reduced by plants.
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Adewale Ajao, Lukman, Emmanuel Adewale Adedokun, Joseph Ebosetale Okhaifoh, and Habib Bello Salau. "A Nonlinear Fuzzy Controller Design using Lyapunov Functions for an Intelligent Greenhouse Management in Agriculture." In Technology in Agriculture [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98409.
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The importance of agronomists in large-scale production of food crops under considerate environmental weather conditions cannot be overemphasized. However, emerging global warming is a threat to food security due to its effect on soil depletion and ecosystem degradation. In this work, the design of the proposed intelligent context is to observe, model and simulate greenhouse control system activity towards the management of the farm crop growth as the affected salient environmental parameters. Characteristically, temperature and humidity are the major factors that determine the crop yield in a greenhouse but the case of a dry air environment or beyond 300C−350C of high air humidity will affect crop growth and productivity. A Mamdani technique of fuzzy logic controller with non-linear consequent is used for intelligent greenhouse design in the LABVIEW virtual environment. This approach is used to mimic the human thought process in the system control by setting some logical rules that guide the greenhouse functions. For the system stabilization achievement, a direct method of Lyapunov functions was proposed. The simulation model result shows that, the average temperature of 18.50C and humidity 65% is achieved for a decent environment of crop growth and development during winter. However, the average temperature and humidity achieved during summer is 27.50C&70% respectively. For every season that is beyond 30.50Cand75% of temperature and humidity will require automation of roof opening and water spilled.
Conference papers on the topic "Humidity of the process gass"
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Li, Jun, Huaqiang Yin, and Xuedong He. "Influence Factors on Moisture Absorption Process of Carbon Material in HTGR." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81412.
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A large amount of carbon material is used in high-temperature gas-cooled reactor (HTGR), with an initial moisture content less than 0.1 %, and under the high temperature condition during reactor’s operation the material would be corroded by chemical corrosion reaction with moisture. The carbon materials in HTGR include carbon material with boron carbide (BC) and graphite IG-110. Based on the moisture absorption experiment of BC, the effective diffusion coefficient D of BC is fitted, and D = 1.35 × 10−9 (m2/s). The experiments shows with the same condition of temperature and humidity, the moisture absorption of BC is higher than that of IG-110. As the environment humidity increases, the moisture absorption increases.
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Berdanier, Reid A., Natalie R. Smith, John C. Fabian, and Nicole L. Key. "Humidity Effects on Experimental Compressor Performance: Corrected Conditions for Real Gases." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25790.
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The effects of humid air on the performance of a multistage research compressor and new methods of humidity accounting to ensure appropriate representation of performance parameters are investigated in this paper. Turbomachinery textbooks present methods of correcting speed and mass flow rate using perfect gas assumptions, but these methods can reduce the ability to achieve repeatable compressor performance when using unconditioned air in a climate where absolute humidity may vary. Instead, a new method is introduced which models humid air as a real gas and circumvents the need for assumptions in the correction process. In the area of compressor research, the ability to measure small changes in performance parameters and ensure repeatable results is essential. Errors of more than 0.5% can result from using perfect gas assumptions to calculate corrected speed, which can lead to misrepresented performance parameters beyond the uncertainty of the measurements. Multiplicative correction factors based on analytical data are also introduced as an alternate method of applying the new real-gas method, and these correction factors are compared to those derived by previous authors applying ideal gas methods for humidity accounting. This is the first time in open literature that experimental results for a component of a gas turbine engine are presented comparing a humid air correction method with traditional correction methods.
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Hauer, M., M. Meyer, D. Billieres, C. Bricquet, F. Gerstgrasser, J. Kiilakoski, J. Lejay, and K. M. Henkel. "Use of Different Process Gases for Manufacturing Isolating Alumina Coatings by Flame Spraying with Cords." In ITSC2021, edited by F. Azarmi, X. Chen, J. Cizek, C. Cojocaru, B. Jodoin, H. Koivuluoto, Y. C. Lau, et al. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.itsc2021p0648.
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Abstract This study assesses the quality of flame-sprayed alumina coatings produced from recently developed alumina cord using argon and compressed air as atomizing gases. Coatings of different thicknesses were deposited on aluminum substrates and then analyzed using optical microscopy, X-ray diffraction, and resistivity measurements. The coatings, particularly those sprayed with argon, had fine microstructure and higher surface and volume resistivity than flame-spray coatings made from alumina cord in the past. They were also found to have higher alpha phase content than plasma-sprayed coatings, regardless of the atomizing gas used. The effect of humidity and the possible formation of aluminum hydroxides are also addressed.
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Nakashima, Kazuhiro, Carlos Morillo, Yoshie Kurono, Yoshinori Sawae, and Joichi Sugimura. "Wear Mechanisms of PTFE in Humidified Hydrogen Gas." In ASME/STLE 2011 International Joint Tribology Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ijtc2011-61180.
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PTFE is used as sealing material of machine elements in hydrogen utilizing machine systems, such as fuel cell vehicles and related infrastructures. It is necessary to know the tribological property of sealing materials in hydrogen gas to realize safety and reliability of machine elements operated in hydrogen environment. In this study, humidity in gases was focused on and its effects on the friction and wear of rubbing pair of PTFE pin and AISI 316L disk was investigated in pin-on-disk wear apparatus. The result indicated that the humidity in hydrogen gas had little effect on the friction coefficient between PTFE and AISI 316L. However, the specific wear rate of unfilled PTFE was clearly affected by the humidity. The amount of PTFE transfer film formed on the stainless surface gradually decreased with decreasing the humidity in hydrogen gas. The similar results could be obtained in inert argon gas as well. Water molecules remained in gaseous environments would be included in the formation process of PTFE transfer film affect on formation of PTFE transfer film. The humidity in hydrogen gas should be regulated to ensure the tribological behavior of the PTFE/stainless sliding pair being used in the hydrogen environment.
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Gourlaouen, V., F. Remy, J. M. Leger, and J. Sattonnet. "Influence of Plasma Gas (Spral 22, Ar/H2) and Impurities (O2, H2O) on the Electrode Lifetime During Spraying." In ITSC 1998, edited by Christian Coddet. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.itsc1998p0797.
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Abstract Electrodes play an important role in the plasma-spraying process and must be frequently replaced to ensure good coating properties. The purpose of this work was to assess the effect of different plasma gases and oxygen and humidity levels on electrode lifetime. The change in arc voltage over time was recorded during spraying, and the elapsed time for a 5V drop was taken as the electrode lifetime. It was found that variations in oxygen and humidity in Ar-H2 gas mixtures have a major effect on lifetime and that the use of SPRAL22 gas could extend electrode life by a factor of three to four. These and other results are discussed in the paper.
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Keske, Justin D., and Jason R. Blough. "Calculating the Speed of Sound in an Engine Exhaust Stream." In ASME 2008 Noise Control and Acoustics Division Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ncad2008-73031.
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The actual speed of sound in the exhaust medium of an engine plays an extensive role in the noise attenuation characteristics of the engine’s muffler system. For 2-stroke engine applications, the speed of sound in the exhaust gas also greatly affects how the expansion chamber is tuned to maintain maximum power output. The combustion process in an engine creates exhaust gases that differ from the composition of atmospheric air. This difference in chemical composition and humidity content yield a different density and ratio of specific heats. These ultimately yield different sound speeds in the exhaust gases compared to atmospheric air. This paper performs a full chemical analysis of the combustion process in an internal combustion gasoline engine to yield the chemical composition of the of the exhaust gases. An algorithm is written to calculate the speed of sound in the exhaust stream. The inputs of the algorithm include measurements of temperature, pressure, and relative humidity of the ambient intake air, specification of the gasoline/ethanol fuel blend, and a direct measurement of the exhaust gas temperature. Comparisons are made between sound speed approximation calculations based on air to calculations obtained by the algorithm.
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Bussman, Wesley R., and Charles E. Baukal. "Ambient Condition Effects on NOx and CO Emissions From Process Heaters." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68284.
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Because process heaters are typically located outside, their operation is subject to the weather. Heaters are typically tuned at a given set of conditions; however, the actual operating conditions may vary dramatically from season to season and sometimes even within a given day. Wind, ambient air temperature, ambient air humidity, and atmospheric pressure can all significantly impact the O2 level, which impacts both the thermal efficiency and the pollution emissions from a process heater. Unfortunately, most natural draft process burners are manually controlled on an infrequent basis. This paper shows how changing ambient conditions can considerably impact both CO and NOx emissions if proper adjustments are not made as the ambient conditions change. Data will be presented for a wide range of operating conditions to show how much the CO and NOx emissions can be affected by changes in the ambient conditions for fuel gas fired natural draft process heaters, which are the most common type used in the hydrocarbon and petrochemical industries. Some type of automated burner control, which is virtually non-existent today in this application, is recommended to adjust for the variations in ambient conditions.
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Liqiang, Duan, Guo Yaofei, Pan Pan, and Li Yongxia. "Study on Effects of Compressor Inlet Air Cooling on GTCC System Performance Under Different Environmental Conditions." In ASME 2020 Power Conference collocated with the 2020 International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/power2020-16764.
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Abstract The environmental conditions (air temperature and relative humidity) have a great impact on the power and efficiency of gas turbine combined cycle (GTCC) system. Using the intake air cooling technology can greatly improve the performance of GTCC system. On the base of the PG9351FA gas turbine combined cycle system, this article builds the models of both the GTCC system and a typical lithium bromide absorption refrigeration system using Aspen Plus software. The effects of compressor inlet air cooling with different environmental conditions on the GTCC system performance are studied. The research results show that using the inlet air cooling technology can obviously increase the output powers of both the gas turbine and the combined cycle power. When the ambient humidity is low, the efficiency of GTCC changes gently; while the ambient humidity is high, the GTCC system efficiency will decline substantially when water in the air is condensed and removed with the progress of cooling process. At the same ambient temperature, when the relative humidity of the environment is equal to 20%, the gas turbine output power is increased by 35.64 MW, with an increase of 16.32%, and the combined cycle output power is increased by 39.57 MW, with an increase of 11.34%. At an ambient temperature of 35°C, for every 2.5 °C drop in the compressor inlet air, the thermal efficiency of the gas turbine increases by 0.189% compared to before cooling.
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Chaker, Mustapha, and Cyrus B. Meher-Homji. "Evaporative Cooling of Gas Turbine Engines: Climatic Analysis and Application in High Humidity Regions." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27866.
Full textAbstract:
There are numerous power generation and mechanical drive gas turbine applications where the power drop caused by high ambient temperatures has a very detrimental effect on the production of power or process throughput. Media evaporative cooling and inlet fogging are common low cost power augmentation techniques applied to reduce these losses. Several misconceptions exist regarding the applicability of evaporative cooling to what are often called “high humidity” regions. There is a sizable evaporative cooling potential in most locations when climatic data is evaluated based on an analysis of coincident wet bulb and dry bulb data. This data is not readily available to plant users and designers. This paper provides a detailed treatment of available climatic data bases and presents actual climatic data from several world wide locations to show that considerable cooling potential actually exists even in high humidity regions. It is hoped that this paper will be of value to plant designers, engineering and operating companies that are considering the use of evaporative cooling for power augmentation.
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Ahn, Hojin, Burhan Gul, Yavuz Sahin, and Onur Hartoka. "Experimental Investigation on the Condensation Efficiency of Humid Air in a Cross-Flow Condenser." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64331.
Full textAbstract:
The condensation of steam in the presence of air has been investigated experimentally in the cross-flow flat-plate single-channel condenser. In particular, the condensation efficiency which is defined by the ratio of heat released during the condensation process (the amount of latent heat) to the total heat extracted from the mixture of vapor and non-condensable gas (the sum of latent and sensible heats) is examined as a function of the air-steam mixture temperature and humidity at inlet and the flow rates of the air-steam mixture and cooling air. The preliminary results are obtained with the operating condition of the air-steam mixture flow at 70°C and 80, 85 and 90% relative humidity at inlet. The most notable result is that the condensation efficiency evidently decreases with the increase of the cooling air flow rate. With both mixture and cooling flow rates kept constant, the condensation efficiency increases, as expected, with the increasing air-steam mixture humidity at the inlet. On the other hand, the air-steam mixture flow rate appears to have little effect on the condensation efficiency.
Reports on the topic "Humidity of the process gass"
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Solaun, Kepa, Chiquita Resomardono, Katharina Hess, Helena Antich, Gerard Alleng, and Adrián Flores. State of the Climate Report: Suriname: Summary for Policy Makers. Inter-American Development Bank, July 2021. http://dx.doi.org/10.18235/0003415.
Full textAbstract:
Several factors contribute to Surinames particular vulnerability to the effects of climate change. It is dependent on fossil fuels, has forests liable to decay, fragile ecosystems, and its low-lying coastal area accounts for 87% of the population and most of the countrys economic activity. Many sectors are at risk of suffering losses and damage caused by gradual changes and extreme events related to climate change. For Suriname to develop sustainably, it should incorporate climate change and its effects into its decision-making process based on scientific- evidence. The State of the Climate Report analyzes Surinames historical climate (1990-2014) and provides climate projections for three time horizons (2020-2044, 2045-2069, 2070-2094) through two emissions scenarios (intermediate/ SSP2-4.5 and severe/ SSP5-8.5). The analysis focuses on changes in sea level, temperature, precipitation, relative humidity, and winds for the seven subnational locations of Paramaribo, Albina, Bigi Pan MUMA, Brokopondo, Kwamalasamutu, Tafelberg Natural Reserve, and Upper Tapanahony. The Report also analyzes climate risk for the countrys ten districts by examining the factors which increase their exposure and vulnerability on the four most important sectors affected by climate change: infrastructure, agriculture, water, and forestry, as well as examining the effects across the sectors. The State of the Climate provides essential inputs for Suriname to develop and update its climate change policies and targets. These policies and targets should serve as enablers for an adequate mainstreaming of climate change adaptation and resilience enhancement into day-to-day government operations.
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Solaun, Kepa, Gerard Alleng, Adrián Flores, Chiquita Resomardono, Katharina Hess, and Helena Antich. State of the Climate Report: Suriname. Inter-American Development Bank, July 2021. http://dx.doi.org/10.18235/0003398.
Full textAbstract:
Suriname is highly vulnerable to the effects of climate change. Among the factors that exacerbate its vulnerability are its dependency on fossil fuels, the degradation of important ecosystems (e.g., mangroves), and the fact that 87% of the population, and most of the countrys economic activity is located within the low-lying coastal area. Many sectors are at risk of suffering losses and damage caused by gradual changes and extreme events related to climate change. For Suriname to develop sustainably, it should incorporate climate change and its effects into its decision-making process based on scientific- evidence. The State of the Climate Report analyzes Surinames historical climate (1990-2014) and provides climate projections for three time horizons (2020-2044, 2045-2069, 2070-2094) through two emissions scenarios (intermediate/ SSP2-4.5 and severe/ SSP5-8.5). The analysis focuses on changes in sea level, temperature, precipitation, relative humidity, and winds for the seven subnational locations of Paramaribo, Albina, Bigi Pan MUMA, Brokopondo, Kwamalasamutu, Tafelberg Natural Reserve, and Upper Tapanahony. The Report also analyzes climate risk for the countrys ten districts by examining the factors which increase their exposure and vulnerability on the four most important sectors affected by climate change: infrastructure, agriculture, water, and forestry, as well as examining the effects across the sectors. The State of the Climate Report provides essential inputs for Suriname to develop and update its climate change policies and targets. These policies and targets should enable an adequate mainstreaming of climate change adaptation and resilience enhancementinto day-to-day government operations. It is expected that the Report will catalyze similar efforts in the future to improve decision-making by providing science-based evidence.