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Literatura académica sobre el tema "Size spectra"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 6 de julio de 2024

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Artículos de revistas sobre el tema "Size spectra"

1

Mandich, M. L. "SPECTROSCOPY OF SIZE-SELECTED SEMICONDUCTOR CLUSTERS: BULK LIKE SPECTRA SEEN IN “MOLECULAR SIZE” CLUSTERS". International Journal of Modern Physics B 06, n.º 23n24 (diciembre de 1992): 3747–56. http://dx.doi.org/10.1142/s0217979292001808.

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Absorption spectra have been obtained for size selected, gas phase neutral semiconductor clusters using resonant one- and two-color photodissociation spectroscopy. We now have spectra for indium phosphide clusters containing up to 14 atoms and for silicon clusters containing up to 70 atoms. These spectra show unexpected similarities between the optical signatures of minute semiconductor clusters and their corresponding bulk forms. Equally unexpected is the spectral regularity that we observe with size for silicon clusters, which challenges all existing theories about their geometric and electronic structures.

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2

Wheeland, Laura J. y George A. Rose. "Acoustic measures of lake community size spectra". Canadian Journal of Fisheries and Aquatic Sciences 73, n.º 4 (abril de 2016): 557–64. http://dx.doi.org/10.1139/cjfas-2014-0446.

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Acoustic methods were tested as an alternative to catch data to measure size spectra of freshwater fish communities in Lac du Bonnet (LdB), Manitoba, Canada. Eleven daytime hydroacoustic surveys conducted in 2011 and 2012 enabled length-frequency spectra of fish communities to be calculated within LdB. Fish echoes tracked and converted to length (>5 cm) formed size spectra with significant linear regressions in all cases (p values < 0.05, R2 values from 0.87 to 0.99). Fish abundance (spectral height) was greater in 2011 (mean ± SD = 0.19 ± 0.15) than in 2012 (–0.19 ± 0.20), decreasing through the summer sampling season. Both abundance and size composition (spectral slope) of fish communities differed between three basins of varying bathymetry, with steepest slopes and lowest heights associated with the shallowest waters. We conclude that acoustically derived size spectra provide an efficient means to detect and monitor fish community dynamics over varied spatial and temporal scales in aquatic ecosystems where fish are not highly aggregated and hence single acoustic targets predominate.

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3

Zhou, Peng, Wei Yang, Minzan Li y Weichao Wang. "A New Coupled Elimination Method of Soil Moisture and Particle Size Interferences on Predicting Soil Total Nitrogen Concentration through Discrete NIR Spectral Band Data". Remote Sensing 13, n.º 4 (19 de febrero de 2021): 762. http://dx.doi.org/10.3390/rs13040762.

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Rapid and accurate measurement of high-resolution soil total nitrogen (TN) information can promote variable rate fertilization, protect the environment, and ensure crop yields. Many scholars focus on exploring the rapid TN detection methods and corresponding soil sensors based on spectral technology. However, soil spectra are easily disturbed by many factors, especially soil moisture and particle size. Real-time elimination of the interferences of these factors is necessary to improve the accuracy and efficiency of measuring TN concentration in farmlands. Although, many methods can be used to eliminate soil moisture and particle size effects on the estimation of soil parameters using continuum spectra. However, the discrete NIR spectral band data can be completely different in the band attribution with continuum spectra, that is, it does not have continuity in the sense of spectra. Thus, relevant elimination methods of soil moisture and particle size effects on continuum spectra do not apply to the discrete NIR spectral band data. To solve this problem, in this study, moisture absorption correction index (MACI) and particle size correction index (PSCI) methods were proposed to eliminate the interferences of soil moisture and particle size, respectively. Soil moisture interference was decreased by normalizing the original spectral band data into standard spectral band data, on the basis of the strong soil moisture absorption band at 1450 nm. For the PSCI method, characteristic bands of soil particle size were identified to be 1361 and 1870 nm firstly. Next, normalized index Np, which calculated wavelengths of 1631 and 1870 nm, was proposed to eliminate soil particle size interference on discrete NIR spectral band data. Finally, a new coupled elimination method of soil moisture and particle size interferences on predicting TN concentration through discrete NIR spectral band data was proposed and evaluated. The six discrete spectral bands (1070, 1130, 1245, 1375, 1550, and 1680 nm) used in the on-the-go detector of TN concentration were selected to verify the new method. Field tests showed that the new coupled method had good effects on eliminating interferences of soil moisture and soil particle size.

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4

Moisseev, Dmitri N. y V. Chandrasekar. "Nonparametric Estimation of Raindrop Size Distributions from Dual-Polarization Radar Spectral Observations". Journal of Atmospheric and Oceanic Technology 24, n.º 6 (junio de 2007): 1008–18. http://dx.doi.org/10.1175/jtech2024.1.

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This paper presents a method to retrieve raindrop size distributions (DSD) from slant profile dual-polarization Doppler spectra observations. It is shown that using radar measurements taken at a high elevation angle raindrop size distributions can be retrieved without making an assumption on the form of a DSD. In this paper it is shown that drop size distributions can be retrieved from Doppler power spectra by compensating for the effect of spectrum broadening and mean velocity shift. To accomplish that, spectrum deconvolution is used where the spectral broadening kernel width and wind velocity are estimated from spectral differential reflectivity measurements. Since convolution kernel is estimated from dual-polarization Doppler spectra observations and does not require observation of a clear-air signal, this method can be used by most radars capable of dual-polarization spectra measurements. To validate the technique, sensitivity of this method to the underlying assumptions and calibration errors is evaluated on realistic simulations of radar observations. Furthermore, performance of the method is illustrated on Colorado State University–University of Chicago–Illinois State Water Survey radar (CSU–CHILL) measurements of stratiform precipitation.

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5

Lo, Su-Chin y Chris W. Brown. "Infrared Spectral Search for Mixtures in Medium-Size Libraries". Applied Spectroscopy 45, n.º 10 (diciembre de 1991): 1621–27. http://dx.doi.org/10.1366/0003702914335256.

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A new algorithm is presented for searching medium-size infrared spectral libraries for the components in spectra of mixtures. The algorithm treats the spectra in the library as an m-component quantitative analysis problem in which each of the library spectra represents a standard mixture having a concentration of 1.0 for that component. Principal component regression (PCR) is used to reduce the dimensionality of the problem and to provide the regression coefficients for determining pseudo-concentrations or composition indices (CI) in mixtures. The PCR analysis is followed by the application of an adaptive filter to remove all similarity of the first target component from the mixture and from a selected subgroup of the library. This is followed by a second PCR analysis on the modified spectral data to identify the next target compound. If the correct target components are selected with successive applications of the adaptive filter, the residuals will approach zero. All components in five two- and three-component mixtures were correctly identified by this new Mix-Match algorithm, whereas only two of the five mixtures were completely identified by a typical dot-product search routine.

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6

Hamilton, Victoria E., Christopher W. Haberle y Thomas G. Mayerhöfer. "Effects of small crystallite size on the thermal infrared (vibrational) spectra of minerals". American Mineralogist 105, n.º 11 (1 de noviembre de 2020): 1756–60. http://dx.doi.org/10.2138/am-2020-7602.

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Abstract The thermal infrared (TIR, or vibrational) emission spectra of a suite of synthetic Mg-Fe olivines exhibit notable differences from their natural igneous counterparts in terms of their band shapes, relative depths, and reduced shifts in some band positions with Mg-Fe solid solution. Comparable reflectance spectra acquired from olivine-dominated matrices and fusion crusts of some carbonaceous chondrite meteorites exhibit similar deviations. Here we show that these unusual spectral characteristics are consistent with crystallite sizes much smaller than the resolution limit of infrared light. We hypothesize that these small crystallites denote abbreviated crystal growth and also may be linked to the size of nucleation sites. Other silicates and non-silicates, such as carbonates, exhibit similar spectral behaviors. Because the spectra of mineral separates are commonly used in the modeling and analysis of comparable bulk rock, meteorite, and remote sensing data, understanding these spectral variations is important to correctly identifying the minerals and interpreting the origin and/or secondary processing histories of natural materials.

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7

Camacho, J. y R. V. Solé. "Scaling in ecological size spectra". Europhysics Letters (EPL) 55, n.º 6 (septiembre de 2001): 774–80. http://dx.doi.org/10.1209/epl/i2001-00347-0.

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8

Hamilton, V. E., P. R. Christensen, H. H. Kaplan, C. W. Haberle, A. D. Rogers, T. D. Glotch, L. B. Breitenfeld et al. "Evidence for limited compositional and particle size variation on asteroid (101955) Bennu from thermal infrared spectroscopy". Astronomy & Astrophysics 650 (junio de 2021): A120. http://dx.doi.org/10.1051/0004-6361/202039728.

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Context. Asteroid (101955) Bennu is the target of NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. The spacecraft’s instruments have characterized Bennu at global and local scales to select a sampling site and provide context for the sample that will be returned to Earth. These observations include thermal infrared spectral characterization by the OSIRIS-REx Thermal Emission Spectrometer (OTES). Aims. To understand the degree of compositional and particle size variation on Bennu, and thereby predict the nature of the returned sample, we studied OTES spectra, which are diagnostic of these properties. Methods. We created and mapped spectral indices and compared them with the distribution of geomorphic features. Comparison to laboratory spectra of aqueously altered carbonaceous chondrites constrains the amount of compositional variability that is observable. Results. The OTES spectra exhibit two end-member shapes (or types), and compositional variability appears limited at the spatial resolution of the observations. The global distribution of these spectral types corresponds with the locations of regions composed of (i) large, dark, relatively rough boulders and (ii) relatively smooth regions lacking large boulders. Conclusions. The two spectral types appear to be diagnostic primarily of particle size variations, with contributions from other properties. The spectra resemble experimental data of solid substrates with very thin accumulations (a few to tens of microns) of fine particles (<~65–100 μm). The dustier surfaces commonly correspond with rougher rocks that may produce and/or act as traps for the particles. Anhydrous silicates are limited in abundance, and the bulk mineralogy is consistent with the most aqueously altered carbonaceous chondrites. We expect the returned samples to include these physical and mineralogical characteristics.

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9

Kobayashi, Takahisa y Ahoro Adachi. "Retrieval of Arbitrarily Shaped Raindrop Size Distributions from Wind Profiler Measurements". Journal of Atmospheric and Oceanic Technology 22, n.º 4 (1 de abril de 2005): 433–42. http://dx.doi.org/10.1175/jtech1705.1.

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Abstract An efficient iterative retrieval method for arbitrarily shaped raindrop size distributions (ITRAN) is developed for Doppler spectra measured with a wind profiler. A measured Doppler spectrum is a convolution of the precipitation spectrum and the turbulent spectrum. Deconvolution of the Doppler spectra is achieved through repeated convolutions. The developed method assumes no prior shape of drop size distributions and automatically obtains raindrop size distributions; additionally, it can be applied to large data volumes. Furthermore, it is insensitive to initial values. The method was applied to both simulated and observed spectra. Derived drop size distributions agree with simulated values. Narrower turbulent spectral widths yield better results. Integral values of median volume diameter (D0), liquid water content (LWC), and radar reflectivity factor are estimated with errors of less than 10%. Accurate vertical profiles of raindrop size distributions result when this method is applied to wind profiler data. The technique performed very well with most observed spectra. Some recovered spectra departed from the corresponding measured spectra, for cases in which a clear-air peak could not be accurately reproduced because of uncertainties in the location of the minimum position between the clear-air echo and the precipitation echo. Statistical relationships between LWC and integral rainfall parameters yield interesting features. The median volume diameter is statistically independent of the LWC and is associated with the large variability of the total number of drops, NT, between events. Vertical profiles from one event show a clear inverse relationship between NT and D0

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10

Cardile, CM, CW Childs y JS Whitton. "The effect of citrate bicarbonate dithionite treatment on standard and soil smectites as evidenced by 57Fe Mössbauer spectroscopy". Soil Research 25, n.º 2 (1987): 145. http://dx.doi.org/10.1071/sr9870145.

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The 57Fe Mossbauer spectra of a selection of smectitic clay fractions of CBD-treated soil samples were measured and computer-fitted with appropriate Fe3+ and Fe2 + resonances. The shape of the Fe3+ spectral envelopes suggested that all the clays were dominated by montmorillonite, contradicting the indications of the Greene-Kelly test. Experiments with untreated and CBD-treated nontronite and montmorillonite showed, however, that the apparent contradiction was probably the result of significant disruption of the smectites by the CBD treatment. The occurrence of this disruption also casts doubt on the validity of using the Greene-Kelly test on CBD-treated samples. The computer-fitted Mossbauer spectra of nontronite with different particle sizes (specifically aggregate size) demonstrated a relationship between particle size and the line-width of the Fe3+ tetrahedral site resonance. This relationship probably reflects an increasing degree of variability in the tetrahedral site with increasing particle size.

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Tesis sobre el tema "Size spectra"

1

Gin, Karina Y. H. (Karina Yew Hoong). "Microbal size spectra from diverse marine ecosystems". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40155.

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2

Datta, Samik. "A mathematical analysis of marine size spectra". Thesis, University of York, 2011. http://etheses.whiterose.ac.uk/1627/.

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Aquatic ecosystems are observed to follow regular patterns in abundance. The frequency distribution of all individuals across the spectrum of body mass, irrespective of their taxonomic identity (known as a ’size spectrum’), follows a power law and this has mathematically been explained by the processes of growth and mortality primarily driven by predation. In this theory of the size spectrum, predation is driven by body size: as organisms grow bigger the size of their prey also increases. This process is thought to be particularly important for marine organisms such as fish, where individual body size is an important determinant for what they eat because they are mostly limited by the size of their mouths. Models need to capture the behaviour of real systems if reliable predictions are to emerge from them. Here, new equations for size-based predation are derived from a stochastic process, allowing variability in organism growth. The new equations are postulated to capture real feeding behaviour better than classical models often used to simulate size spectra. Marine systems are often perturbed by seasonal processes, environmental factors and exploitation. I show how models with diffusive growth stabilise the observed power-law steady state in marine systems, and stability is explicitly linked to parameters involved in feeding. Seasonal plankton blooms are introduced into the model, along with time-dependent reproduction, both of which are widely observed in aquatic systems. The population dynamics, along with growth and survival rates during blooms are investigated, and preliminary results are reflected in empirical data. The match/mismatch hypothesis is tested, with theoretical findings in agreement with observed seasonal trends. Adding factors such as these will make the behaviour of size-based models more indicative of real ecosystems, and thus well-informed management decisions about exploitation can be made.

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3

San, Martin Elena. "Latitudinal variation in plankton size spectra along the Atlantic Ocean". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/41351/.

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Abundance-size distributions of organisms within a community reflect fundamental properties underlying population dynamics. These include characteristics such as predator to prey biomass ratios, given the relationships that exist between body mass and metabolic activity, and between body mass and the ecological regulation of population density. In this way, plankton size has an important role in structuring the rates and pathways of material transfer in the marine pelagic food web, and consequently the oceanic carbon cycle. The transfer of energy between trophic levels can be inferred from regular patterns in population size structure, where plots of abundance within size classes, also known as plankton size spectra, typically show a power-law dependence on size. Metabolic theory, based on such size relations, has provided the basis for using an allometric approach to investigate the metabolic balance of the Atlantic Ocean and to identify the main drivers of trophic status in the plankton community. Samples were collected during three Atlantic Meridional Transect (AMT) cruises with further samples from a Marine Productivity (MarProd) cruise in the Irminger Sea. Three image analysis instruments were used to obtain plankton size spectra in the pico- to mesozooplankton size range. Data from a decadal time series at a coastal station off Plymouth, UK additionally enabled seasonal trends in plankton size spectra to be interpreted. Allometric relationships were also derived from physiological rates of individual plankton and scaled from organisms to ecosystems using community size structure data that were obtained from six earlier AMT cruises. Contrary to common perception, the transfer efficiency between phytoplankton and mesozooplankton in the Atlantic was not related to ecosystem productivity in oceanic and coastal systems. The flow of carbon up the food web was controlled by how quickly the consumers are able to respond to a resource pulse. These findings have fundamental implications for upper ocean carbon flux and suggest that global carbon flux models should reconsider the differences in carbon transfer efficiency between productive and oligotrophic areas of the world’s ocean. The allometric models of microbial community respiration and production provide a complementary method for understanding the metabolic balance of the upper ocean. Respiration exceeded photosynthesis in large areas of the Atlantic Ocean, suggesting that planktonic communities act as potential net sources of CO2. Large-sized phytoplankton are suggested as the main drivers of the balance between net autotrophy and heterotrophy.

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4

Riva, Valentina. "Semiclassical methods in 2D QFT: spectra and finite-size effects". Doctoral thesis, SISSA, 2004. http://hdl.handle.net/20.500.11767/3955.

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In this thesis, we describe some recent results obtained in the analysis of two-dimensional quantum field theories by means of semiclassical techniques. These achievements represent a natural development of the non-perturbative studies performed in the past years for conformally invariant and integrable theories, which have lead to analytical predictions for several measurable quantities in the universality classes of statistical systems. Here we propose a semiclassical method to control analytically the spectrum and the finite-size effects in both integrable and non-integrable theories. The techniques used are appropriate generalization of the ones introduced in seminal works during the Seventies by Dashen, Hasllacher and Neveu and by Goldstone and Jackiw. Their approaches, which do not require integrability and therefore can be applied to a large class of system, are best suited to deal with those quantum field theories characterized by a non-linear interaction potential with different degenerate minima. In fact, these systems display kink excitations which generally have a large mass in the small coupling regime. Under these circumstances, although the results obtained are based on a small coupling assumption, they are nevertheless non-perturbative, since the kink backgrounds around which the semiclassical expansion is performed are non-perturbative too.

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5

Williams, Diane Keith. "Particle Size Dependence on the Luminescence Spectra of Eu3+:Y2O3 and Eu3+:CaO". Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29719.

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Since the Eu3+ ion can occupy different cation sites in a host material, it can serve as a useful probe of nanocrystalline structures to gain more insight into the structural changes that can occur when the particle size is reduced from the bulk to nanometer regime. The use of laser spectroscopy to probe two nanocrystalline structures, Eu3+:Y2O3 and Eu3+:CaO, was investigated. The nanocrystalline structures were prepared by the laser-vaporization-gas-phase condensation of the bulk oxides. The particle size distribution and dominant particle diameters of the nanocrystals were determined by transmission electron microscopy. The particle size dependency results of Eu3+:Y2O3 revealed three distinct phases: (1) the sharp lines of the monoclinic Y2O3 were dominant in the larger particles; (2) the C2 site of the cubic phase, which appears in the smaller particles; and (3) the amorphous phase that increases in intensity as the particle size decreases. The observation of distinct spectral lines from the monoclinic phase confirms the presence of a crystalline phase for all of particle sizes studied. The site-selective results of various concentrations of 13-nm Eu3+:CaO showed that the laser-vaporization-gas-phase condensation method of preparation produced two europium-containing phases at most concentrations: cubic CaO and monoclinic Eu2O3. Results showed that the monoclinic Eu2O3 phase could be reduced by 95% by annealing at 800 0C for 30 minutes without particle growth. Since the Eu3+ ion and the Y3+ ion are isovalent, the substitution of a Eu3+ ion into Y2O3 is considered a trivial case of extrinsic disorder since the impurity is neutral relative to a perfect crystal1. As a result, it is not necessary to have any other defects present in the crystals to maintain charge neutrality. With Eu3+:CaO, the dopant and host cation charges are different and therefore the dopant distribution can be investigated by site-selective spectroscopy. Since the experimental dopant distribution results for nanocrystalline Eu3+:CaO were inconclusive, a model to predict the theoretical change in the dopant distribution in Eu3+:CaO as a function of particle size was developed. The model predicts that the defect chemistry is affected when the particle size is approximately 50 nm and smaller.
Ph. D.

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6

Kirk, Andrew J. "Seasonal Variation of Fish and Macroinvertebrate Biomass Spectra in Southern West Virginia Streams". VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4228.

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The biomass size spectrum - the power-law scaling relationship between average individual size and total biomass - has often been studied in lake and marine ecosystems, but rarely in lotic systems. The objective of this study was to test for characteristic biomass spectra in small temperate streams. Seasonal fish and macroinvertebrate data, including population abundance and biomass estimates, were collected in three wadeable, southern West Virginia streams from October 2013 to May 2015. Fish abundances were estimated with 3-pass electrofishing (depletion) surveys and individuals were weighed in the field. Macroinvertebrates were collected with a Hess sampler and returned to the lab for identification to the lowest practical level (usually genus). Published length-mass regressions were then used to estimate individual mass. All size spectra relationships (linear regression of log-log data) were highly significant (p<0.001). Size spectra intercepts were variable and may reflect seasonal differences in fish and invertebrate densities. Size spectra slopes were more consistent, with a mean slope of approximately -0.73, suggesting a common scaling relationship between stream consumers at differing trophic levels.

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7

Abada, Ahmed El-Sayed Ahmed. "From rivers to oceans : a comparison of contrasting aquatic ecosystems using benthic size spectra". Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/1671.

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This thesis uses a range of different size spectra to compare contrasting benthic habitats in the aquatic realm. Temporal and spatial variation in benthic size spectra were investigated across a full salinity gradient (i.e. from freshwater, through estuarine to marine) in the River Yealm, south Devon, in order to gauge the influence of large differences in taxonomy and evolutionary history. Abundance and biomass size spectra showed a similar pattern among sites in all seasons but winter, suggesting that the size structure of benthic communities may be similar in sites with very different community compositions. A subsequent study comparing size spectra across salinity by employing artificial substrata suggested that substratum type also had little effect on the size structure of these benthic communities. A technique was developed for obtaining microbial size distributions for benthic communities and showed that microbial size structures were also similar between the marine and freshwater sites within the Yealm system. A final study demonstrated that the shape of size spectra was clearly affected by metal contamination. Size spectra across a salinity gradient -(i.e. from freshwater to lower estuary) in the highly contaminated Fal system were very different to those in the uncontaminated Yealm, due mostly to the low macrofaunal abundance in the former. This thesis is the first to assess patterns in benthic size spectra across a full salinity range in the same system. It is hoped that it will provide a base line for further studies in this exciting research area in macroecology and that biomass spectra might also prove useful as metrics for biomonitoring.

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8

Huang, Jimin. "Influence of cation size and surface coverage upon the infrared spectrum of carbon monoxide". Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/42155.

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Adsorbed carbon monoxide is utilized as a double layer probe molecule because of its strong absorption in infrared region and because of the high sensitivity of the carbon-oxygen bond to changes in the environment local to the electrode surface. Potential Difference Infrared Spectroscopy was used to investigate the structural behavior of CO adsorbed on a platinum electrode. Carbon monoxide was found to be exclusively linear-bonded on platinum electrode in the presence of tetran- alkylammonium perchlorate/acetonitrile. No bridge-bonded species were observed. It was also found that the IR peak position of adsorbed CO is linearly dependent upon applied electrode potential, in agreement with Electrochemical Stark effect. The Stark tuning rate of adsorbed CO was determined to be inversely proportional to electrolyte cation size. This quantitative relationship between the Stark tuning rate and cation size is the first time that this has been experimentally demonstrated. Statistical treatment proved that surface coverage influences the rate of infrared peak position shift. The effect of surface coverage upon the conformation of tetra-n-octylammonium cation was also observed. Data suggested that tetra-n-octylammonium cation changes its conformation with surface coverage
Master of Science

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9

Marcolin, Catarina da Rocha. "Plankton and particle biomass size spectra on the Southwest Atlantic: Case studies in tropical and subtropical areas". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-12052014-173357/.

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This thesis is centered on the application of the Normalized Biomass Size Spectra (NBSS) theory to the study of plankton systems in shelf and oceanic areas of the tropical and subtropical Southwest Atlantic. I evaluated NBSS parameters over different environmental settings and their utility as proxies for system in Brazilian waters. The LOPC and the ZooScan are recently developed optical systems to automatically detect and measure plankton and particle size distributions in situ and in laboratory, respectively. I present two case studies: the first deals with the spatial variability over the Abrolhos Bank and adjacent oceanic areas in tropical latitudes, and the second focuses on temporal variability of plankton communities along a 5-year time series on a fixed station on the inner shelf at a subtropical location (Ubatuba, São Paulo). The data sets consisted of vertical profiles obtained with a LOPC and plankton preserved samples collected with a 200-m-mesh net. I observed in both data sets the accumulation of small particles (< 1 mm) above and within the pycnocline. NBSS slopes and intercepts were significantly different according to the contrasting environmental conditions observed in both areas; higher intercepts and steeper slopes were associated with higher productivity. The results highlight: i) water-column stratification as a key feature driving particle and plankton vertical distribution, ii) NBSS parameters as indicators of different environmental settings, and iii) that the cold and nutrient-rich South Atlantic Central Water (SACW) have an important role structuring the zooplankton size distributions over the Abrolhos Bank and vicinities and off Ubatuba. The NBSS parameters associated with information on plankton composition and distributions provided important information to evaluate the influence of oceanographic forcing on plankton dynamics in distinct ecosystems of the Southwest Atlantic
O tema central desta tese é a aplicação da teoria do espectro de biomassa normalizado (NBSS, em inglês) no estudo de sistemas planctônicos em áreas costeiras e oceânicas, no Atlântico Sudoeste tropical e subtropical. Eu avaliei os parâmetros do NBSS em diferentes situações ambientais na Plataforma Continental Brasileira e a utilidade desses índices para inferir sobre produtividade. O LOPC e o ZooScan são sistemas ópticos recentemente desenvolvidos para detectar e mensurar a distribuição de tamanhos de partículas e zooplâncton in situ e em laboratório, respectivamente. Eu apresento dois estudos de caso: o primeiro lida com a variabilidade espacial sobre o banco de Abrolhos e áreas adjacentes oceânicas em latitudes tropicais, enquanto o segundo enfatiza a variabilidade temporal de comunidades planctônicas ao longo de 5 anos numa estação fixa na plataforma interna em uma localidade subtropical (Ubatuba, SP). O conjunto de dados consistiu de perfis verticais obtidos com o LOPC e com rede de plâncton, malha de 200-m. Eu observei o acúmulo de partículas < 1 mm na picnoclina e acima desta de forma consistente. Ambos inclinação e intercepto das retas ajustadas ao NBSS responderam à condições ambientais contrastantes em ambas as áreas; associamos interceptos maiores e inclinações mais negativas com maior produtividade do plâncton. Os principais resultados indicam: i) que a estratificação é um fator chave na distribuição vertical de partículas e do plâncton, ii) os parâmetros do NBSS como indicadores de diferentes condições ambientais e iii) que a Água Central do Atlântico Sul (ACAS, fria e rica em nutrientes) tem um importante papel na estruturação da distribuição de tamanhos acima do Banco de Abrolhos e proximidades e ao largo de Ubatuba. Os parâmetros do NBSS, associados com informações sobre a composição taxonômica e distribuição do plâncton foram importantes para avaliar a influência de feições oceanográficas sobre a dinâmica do mesozooplâncton em diferentes ecossistemas no Atlântico Sudoeste

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Rebecca, D'Onofrio. "Effect of Permafrost Thaw Slumps on Benthic Invertebrates and on Concentrations of Persistent Organic Pollutants in Lakes of the Mackenzie Delta Uplands, NT". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31188.

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Permafrost thaw slumping along lakeshores in lakes of the Mackenzie Delta Uplands, NT is known to alter water chemistry significantly. Its impact on benthic communities and persistent organic pollutant (POP) behaviour in lakes is not known. Benthic invertebrate communities responded to slumps through changes to community composition and size spectra. Larger taxa tended to dominate in lakes with slumps. Variability in biomass size spectra was related to total dissolved nitrogen concentration and slump size. Concentrations of POPs in Gammarus were negatively correlated with total phosphorus and positively correlated with the percentage of the catchment slumped. Lakes with slumps generally had higher mean concentrations of POPs in Gammarus (ex. ΣPCBsDisturbed = 27.54 ng/g lipid, ΣPCBsUndisturbed = 16.97 ng/g lipid; ΣDDT Disturbed =18.47 ng/g lipid and ΣDDTUndisturbed =10.86 ng/g lipid). Benthic invertebrate biomass was also negatively correlated with concentrations of contaminants in Gammarus, supporting the biomass dilution hypothesis. Thaw slumps have large enough impacts on the physico-chemical characteristics of lakes that they alter benthic invertebrate community composition and size-structure, and contaminant concentrations in Gammarus.

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Libros sobre el tema "Size spectra"

1

Gin, Karina Y. H. Microbial size spectra from diverse marine ecosystems. Woods Hole, Mass: Woods Hole Oceanographic Institution, 1996.

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Barry, John Willard y Patricia J. Skyler. Final report: Compendium of drop size spectra compiled from wind tunnel tests. Davis, CA: USDA Forest Service, Forest Pest Management, 1991.

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Yates, Wesley E. Drop size spectra of Dipel 8L and Thuricide 48LV atomized with a Micronair. Davis, CA: U.S. Dept. of Agriculture, Forest Service, Forest Pest Management, 1985.

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Ishkhanov, B. S. Razmer i forma atomnykh i͡a︡der. Moskva: Izd-vo Moskovskogo universiteta, 1990.

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United States. National Aeronautics and Space Administration., ed. A study of the spatial scales of discrete polar auroral arcs. El Segundo, Calif: Aerospace Corp., 1989.

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Bernreuter, D. L. Development of site specific response spectra. Washington, DC: Division of Engineering Safety, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1987.

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Bernreuter, D. L. Development of site specific response spectra. Washington, DC: Division of Engineering Safety, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1987.

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Lindley, Grant T. Analysis of source spectra, attenuation, and site effects from central and eastern United States earthquakes. Washington, D.C: U.S. Nuclear Regulatory Commission, 1998.

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U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Engineering Technology., University of California, Santa Barbara. Institute for Crustal Studies. y U.S. Nuclear Regulatory Commission., eds. Analysis of source spectra, attenuation, and site effects from central and eastern United States earthquakes. Washington, DC: Division of Engineering Technology, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1998.

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C, Seekins L. y Geological Survey (U.S.), eds. Response spectra from the 1989 Loma Prieta, California, earthquake regressed for site amplification, attenuation, and directivity. [Menlo Park, CA]: U.S. Dept. of the Interior, U.S. Geological Survey, 1997.

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Capítulos de libros sobre el tema "Size spectra"

1

Buser, Peter. "The Size of Isospectral Families". En Geometry and Spectra of Compact Riemann Surfaces, 340–61. Boston: Birkhäuser Boston, 2010. http://dx.doi.org/10.1007/978-0-8176-4992-0_13.

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Kislyuk, V. V., G. M. Strilchuk, V. Z. Lozovski, M. M. Osipyonok y P. M. Lytvyn. "Influence of particle size on luminescence spectra". En From Colloids to Nanotechnology, 24–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-45119-8_4.

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Kourti, T., A. Penlidis, J. F. MacGregor y A. E. Hamielec. "Measuring Particle Size Distribution of Latex Particles in the Submicrometer Range Using Size-Exclusion Chromatography and Turbidity Spectra". En Particle Size Distribution, 242–55. Washington, DC: American Chemical Society, 1987. http://dx.doi.org/10.1021/bk-1987-0332.ch017.

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Hunter, Keith A. "Surface Charge and Size Spectra of Marine Particles". En Marine Particles: Analysis and Characterization, 259–62. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm063p0259.

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Tsuda, Ryohei, Michio Kumagai y Yoshimi Kakui. "Spatial changes of phytoplanktonic size spectra in Lake Biwa". En The Dynamics and Use of Lacustrine Ecosystems, 137–40. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2745-5_13.

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Bosilj, Petra, Iain Gould, Tom Duckett y Grzegorz Cielniak. "Pattern Spectra from Different Component Trees for Estimating Soil Size Distribution". En Lecture Notes in Computer Science, 415–27. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20867-7_32.

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Bréchignac, C. y Ph Cahuzac. "Evolution of Photoionization Spectra of Metal Clusters as a Function of Size". En Metal Clusters, 21–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-71571-6_4.

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Bailey-Watts, A. E. "Seasonal variation in size spectra of phytoplankton assemblages in Loch Leven, Scotland". En Seasonality of Freshwater Phytoplankton, 25–42. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4818-1_3.

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Haedrich, Richard L. y Nigel R. Merrett. "Production/Biomass Ratios, Size Frequencies and Biomass Spectra in Deep-Sea Demersal Fishes". En Deep-Sea Food Chains and the Global Carbon Cycle, 157–82. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2452-2_10.

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Nazir, Rabia, Muhammad Mazhar, Muhammad Siddique y S. Tajammul Hussain. "Effect of particle size and alloying with different metals on 57Fe Mössbauer spectra". En ISIAME 2008, 85–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-01370-6_10.

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Actas de conferencias sobre el tema "Size spectra"

1

Vinogradov, E. A. "Size effects in vibrational polariton spectra". En 18th International Conference on Infrared and Millimeter Waves. SPIE, 1993. http://dx.doi.org/10.1117/12.2298595.

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Liang, Haoran y Zhe Wu. "Measuring the fine-structure constant on quasar spectra: High spectral resolution gains more than large size of moderate spectral resolution spectra". En International Workshop on Frontiers of Graphics and Image Processing (FGIP 2022), editado por Elma Wong, Shinan Lang y Xiaoyue Jiang. SPIE, 2023. http://dx.doi.org/10.1117/12.2670012.

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Haberland, H., Bernd von Issendorf, Yufing Ji y Thomas Kolar. "Optical spectra of size-selected mercury cluster ions". En OE/LASE'93: Optics, Electro-Optics, & Laser Applications in Science& Engineering, editado por Cheuk Yiu Ng. SPIE, 1993. http://dx.doi.org/10.1117/12.143234.

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Myers, Tanya L., Carolyn S. Brauer, Yin-Fong Su, Thomas A. Blake, Timothy J. Johnson y Robert L. Richardson. "The influence of particle size on infrared reflectance spectra". En SPIE Defense + Security, editado por Miguel Velez-Reyes y Fred A. Kruse. SPIE, 2014. http://dx.doi.org/10.1117/12.2053350.

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Pate, Brooks y Channing Perez, West. "SIZE-SELECTED SPECTRA OF WATER CLUSTERS USING ISOTOPE DILUTION". En 2023 International Symposium on Molecular Spectroscopy. Urbana, Illinois: University of Illinois at Urbana-Champaign, 2023. http://dx.doi.org/10.15278/isms.2023.7206.

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MacDonald, M. P., A. Cochran, C. J. Weijer, D. Hughes, C. Demore, G. Brodie, G. C. Spalding et al. "Sonotweezers: complementing the size and force spectra of optical trapping". En Optical Trapping Applications. Washington, D.C.: OSA, 2011. http://dx.doi.org/10.1364/ota.2011.ottub4.

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Beiswenger, Toya N., Tanya L. Myers, Carolyn S. Brauer, Yin-Fong Su, Thomas A. Blake, Alyssa B. Ertel, Russell G. Tonkyn et al. "Experimental effects on IR reflectance spectra: particle size and morphology". En SPIE Defense + Security, editado por Miguel Velez-Reyes y David W. Messinger. SPIE, 2016. http://dx.doi.org/10.1117/12.2223909.

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Teng, Yuehui, Chun Huang y Wei Fan. "The estimation of bubble-size spectra and its error analysis". En 2015 International Industrial Informatics and Computer Engineering Conference. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/iiicec-15.2015.373.

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Su, Yin-Fong, Tanya L. Myers, Carolyn S. Brauer, Thomas A. Blake, Brenda M. Forland, J. E. Szecsody y Timothy J. Johnson. "Infrared reflectance spectra: effects of particle size, provenance and preparation". En SPIE Security + Defence, editado por Douglas Burgess, Gari Owen, Harbinder Rana, Roberto Zamboni, François Kajzar y Attila A. Szep. SPIE, 2014. http://dx.doi.org/10.1117/12.2069954.

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Arnott, W. Patrick, Y. Liu, Carl Schmitt y John Hallett. "The Unreasonable Effectiveness of Mimicking Measured Infrared Extinction by Hexagonal Ice Crystals With Mie Ice Spheres". En Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/orsa.1997.othc.3.

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An armada of infrared1-2 and other remote sensing equipment have been developed and deployed to characterize clouds from the ground, from airplanes, and from satellites. Perhaps someday we will be able to trust this equipment to provide all the information we need about clouds - we no longer will have to fly through them and directly record particle statistics - but first, we must properly invert cloud radiative signatures to obtain particle information. To invert, obvious common thought has been that we must have proper numerical models for the single scattering properties of generally nonspherical cloud particles. We have been using a cloud box in the laboratory to measure radiative properties of spherical water3 and hexagonal ice particles4 in a controlled environment where clouds can be well characterized. Our first spectral extinction measurements (2-18 µm) were performed on ice clouds grown near water saturation at a variety of temperatures so that a wide range of particle morphologies from nearly equi-axed columns to sector plates were observed.4 Then we measured spectral extinction by water clouds so we could learn how to invert, using Lorenz-Mie theory, the extinction spectra to obtain particle size spectra, with the larger goal in mind of eventually retrieving ice particle size spectra using the discrete dipole approximation.3 We decided to first apply the inversion based on the Lorenz-Mie theory for ice spheres to the measured ice spectra (mostly so we could grin and giggle at the anticipated poor results), and found much to our surprise that the retrieved IR spectra matched the measurements even better than the water cloud results! Though the retrieved ice sphere size spectra are qualitatively in accord with the measured results, we have not yet found a proper principle to guide us in converting from the geometry of a hexagonal ice crystal to the geometry of a sphere. Ok, so the Mie model seems to work for mimicking the infrared spectral extinction by ice crystals, but are the inverted size spectra reasonable and useful? Come to the talk and find out.

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Informes sobre el tema "Size spectra"

1

Alchanatis, Victor, Stephen W. Searcy, Moshe Meron, W. Lee, G. Y. Li y A. Ben Porath. Prediction of Nitrogen Stress Using Reflectance Techniques. United States Department of Agriculture, noviembre de 2001. http://dx.doi.org/10.32747/2001.7580664.bard.

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Commercial agriculture has come under increasing pressure to reduce nitrogen fertilizer inputs in order to minimize potential nonpoint source pollution of ground and surface waters. This has resulted in increased interest in site specific fertilizer management. One way to solve pollution problems would be to determine crop nutrient needs in real time, using remote detection, and regulating fertilizer dispensed by an applicator. By detecting actual plant needs, only the additional nitrogen necessary to optimize production would be supplied. This research aimed to develop techniques for real time assessment of nitrogen status of corn using a mobile sensor with the potential to regulate nitrogen application based on data from that sensor. Specifically, the research first attempted to determine the system parameters necessary to optimize reflectance spectra of corn plants as a function of growth stage, chlorophyll and nitrogen status. In addition to that, an adaptable, multispectral sensor and the signal processing algorithm to provide real time, in-field assessment of corn nitrogen status was developed. Spectral characteristics of corn leaves reflectance were investigated in order to estimate the nitrogen status of the plants, using a commercial laboratory spectrometer. Statistical models relating leaf N and reflectance spectra were developed for both greenhouse and field plots. A basis was established for assessing nitrogen status using spectral reflectance from plant canopies. The combined effect of variety and N treatment was studied by measuring the reflectance of three varieties of different leaf characteristic color and five different N treatments. The variety effect on the reflectance at 552 nm was not significant (a = 0.01), while canonical discriminant analysis showed promising results for distinguishing different variety and N treatment, using spectral reflectance. Ambient illumination was found inappropriate for reliable, one-beam spectral reflectance measurement of the plants canopy due to the strong spectral lines of sunlight. Therefore, artificial light was consequently used. For in-field N status measurement, a dark chamber was constructed, to include the sensor, along with artificial illumination. Two different approaches were tested (i) use of spatially scattered artificial light, and (ii) use of collimated artificial light beam. It was found that the collimated beam along with a proper design of the sensor-beam geometry yielded the best results in terms of reducing the noise due to variable background, and maintaining the same distance from the sensor to the sample point of the canopy. A multispectral sensor assembly, based on a linear variable filter was designed, constructed and tested. The sensor assembly combined two sensors to cover the range of 400 to 1100 nm, a mounting frame, and a field data acquisition system. Using the mobile dark chamber and the developed sensor, as well as an off-the-shelf sensor, in- field nitrogen status of the plants canopy was measured. Statistical analysis of the acquired in-field data showed that the nitrogen status of the com leaves can be predicted with a SEP (Standard Error of Prediction) of 0.27%. The stage of maturity of the crop affected the relationship between the reflectance spectrum and the nitrogen status of the leaves. Specifically, the best prediction results were obtained when a separate model was used for each maturity stage. In-field assessment of the nitrogen status of corn leaves was successfully carried out by non contact measurement of the reflectance spectrum. This technology is now mature to be incorporated in field implements for on-line control of fertilizer application.

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Stephenson, D. E. Savannah River Site disaggregated seismic spectra. Office of Scientific and Technical Information (OSTI), febrero de 1993. http://dx.doi.org/10.2172/6366499.

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Stephenson, D. E. Savannah River Site disaggregated seismic spectra. Office of Scientific and Technical Information (OSTI), febrero de 1993. http://dx.doi.org/10.2172/10165069.

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Mazzoni, Silvia, Nicholas Gregor, Linda Al Atik, Yousef Bozorgnia, David Welch y Gregory Deierlein. Probabilistic Seismic Hazard Analysis and Selecting and Scaling of Ground-Motion Records (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, noviembre de 2020. http://dx.doi.org/10.55461/zjdn7385.

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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 3 (WG3), Task 3.1: Selecting and Scaling Ground-motion records. The objective of Task 3.1 is to provide suites of ground motions to be used by other working groups (WGs), especially Working Group 5: Analytical Modeling (WG5) for Simulation Studies. The ground motions used in the numerical simulations are intended to represent seismic hazard at the building site. The seismic hazard is dependent on the location of the site relative to seismic sources, the characteristics of the seismic sources in the region and the local soil conditions at the site. To achieve a proper representation of hazard across the State of California, ten sites were selected, and a site-specific probabilistic seismic hazard analysis (PSHA) was performed at each of these sites for both a soft soil (Vs30 = 270 m/sec) and a stiff soil (Vs30=760 m/sec). The PSHA used the UCERF3 seismic source model, which represents the latest seismic source model adopted by the USGS [2013] and NGA-West2 ground-motion models. The PSHA was carried out for structural periods ranging from 0.01 to 10 sec. At each site and soil class, the results from the PSHA—hazard curves, hazard deaggregation, and uniform-hazard spectra (UHS)—were extracted for a series of ten return periods, prescribed by WG5 and WG6, ranging from 15.5–2500 years. For each case (site, soil class, and return period), the UHS was used as the target spectrum for selection and modification of a suite of ground motions. Additionally, another set of target spectra based on “Conditional Spectra” (CS), which are more realistic than UHS, was developed [Baker and Lee 2018]. The Conditional Spectra are defined by the median (Conditional Mean Spectrum) and a period-dependent variance. A suite of at least 40 record pairs (horizontal) were selected and modified for each return period and target-spectrum type. Thus, for each ground-motion suite, 40 or more record pairs were selected using the deaggregation of the hazard, resulting in more than 200 record pairs per target-spectrum type at each site. The suites contained more than 40 records in case some were rejected by the modelers due to secondary characteristics; however, none were rejected, and the complete set was used. For the case of UHS as the target spectrum, the selected motions were modified (scaled) such that the average of the median spectrum (RotD50) [Boore 2010] of the ground-motion pairs follow the target spectrum closely within the period range of interest to the analysts. In communications with WG5 researchers, for ground-motion (time histories, or time series) selection and modification, a period range between 0.01–2.0 sec was selected for this specific application for the project. The duration metrics and pulse characteristics of the records were also used in the final selection of ground motions. The damping ratio for the PSHA and ground-motion target spectra was set to 5%, which is standard practice in engineering applications. For the cases where the CS was used as the target spectrum, the ground-motion suites were selected and scaled using a modified version of the conditional spectrum ground-motion selection tool (CS-GMS tool) developed by Baker and Lee [2018]. This tool selects and scales a suite of ground motions to meet both the median and the user-defined variability. This variability is defined by the relationship developed by Baker and Jayaram [2008]. The computation of CS requires a structural period for the conditional model. In collaboration with WG5 researchers, a conditioning period of 0.25 sec was selected as a representative of the fundamental mode of vibration of the buildings of interest in this study. Working Group 5 carried out a sensitivity analysis of using other conditioning periods, and the results and discussion of selection of conditioning period are reported in Section 4 of the WG5 PEER report entitled Technical Background Report for Structural Analysis and Performance Assessment. The WG3.1 report presents a summary of the selected sites, the seismic-source characterization model, and the ground-motion characterization model used in the PSHA, followed by selection and modification of suites of ground motions. The Record Sequence Number (RSN) and the associated scale factors are tabulated in the Appendices of this report, and the actual time-series files can be downloaded from the PEER Ground-motion database Portal (https://ngawest2.berkeley.edu/)(link is external).

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Tallman, A. M. Seismic design spectra 200 West and East Areas DOE Hanford Site, Washington. Office of Scientific and Technical Information (OSTI), diciembre de 1995. http://dx.doi.org/10.2172/10105001.

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Kottke, Albert, Norman Abrahamson, David Boore, Yousef Bozorgnia, Christine Goulet, Justin Hollenback, Tadahiro Kishida et al. Selection of Random Vibration Procedures for the NGA-East Project. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, noviembre de 2018. http://dx.doi.org/10.55461/ltmu9309.

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Pseudo-spectral acceleration (PSA) is the most commonly used intensity measure in earthquake engineering as it serves as a simple approximate predictor of structural response for many types of systems. Therefore, most ground-motion models (GMMs, aka GMPEs) provide median and standard deviation PSA using a suite of input parameters characterizing the source, path, and site effects. Unfortunately, PSA is a complex metric: the PSA for a single oscillator frequency depends on the Fourier amplitudes across a range of frequencies. The Fourier amplitude spectrum (FAS) is an appealing alternative because its simple linear superposition allows effects to be modeled as transfer functions. For this reason, most seismological models, i.e., the source spectrum, are developed for the FAS. Using FAS in conjunction with random-vibration theory (RVT) allows GMM developers to superimpose seismological models directly, computing PSA only at the end of the process. The FAS-RVT-PSA approach was first used by the Hollenback et al. team in their development of GMMs for the Next Generation Attenuation Relationships for Central & Eastern North-America (NGA-East) project (see Chapter 11 of PEER Report No. 2015/04). As part of the NGA-East project to support the Hollenback et al. team and similar efforts, the current report summarizes a systematic processing algorithm for FAS that minimizes computational requirements and bias that results from the RVT approximation for median GMM development.

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Pursley, M. B. y H. B. Russell. Side Information in Spread-Spectrum Packet Radio Networks. Fort Belvoir, VA: Defense Technical Information Center, junio de 1991. http://dx.doi.org/10.21236/ada238215.

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Lindley, G. Analysis of source spectra, attenuation, and site effects from central and eastern United States earthquakes. Office of Scientific and Technical Information (OSTI), febrero de 1998. http://dx.doi.org/10.2172/576070.

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Lévesque, J., T. Szeredi, K. Staenz y V. Singhroy. Spectral Band Selection from casi Data for Monitoring Mine Tailings Site Rehabilitation. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1998. http://dx.doi.org/10.4095/219355.

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Rosenfeld. L51810 Guidelines for the Assessment of Dents on Welds. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), diciembre de 1999. http://dx.doi.org/10.55274/r0010605.

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The Guidelines for the Assessment of Dents on Welds describes a method for evaluating the serviceability of pipeline girth welds affected by otherwise plain, shallow indentations that are free to reround under pressure. The user makes a cumulative fatigue damage assessment, considering the effects of dent size, weld quality, and the severity of the pipeline operating pressure spectrum. An accompanying diskette provides a rainflow cycle-counting algorithm for use in evaluating the operating pressure spectrum, along with other spreadsheet tools to facilitate the analysis. The serviceability is established by an estimate of the pressure-fatigue life of the weld-dent combination. Examples are presented. Field inspection and repair issues are also discussed.

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