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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Comparison of Methods for Detection of Listeria on Wooden Shelves used for Cheese Aging: Challenges Associated with Sampling Porous Surfaces

Frontino, Gina Christine 01 January 2019 (has links)
This thesis examined the efficacy of various sampling and detection methods used for environmental monitoring of Listeria species on wooden surfaces used for cheese aging. Government agencies including the Food and Drug Administration (FDA) and United States Department of Agriculture (USDA) recommend enrichment methods coupled with use of environmental sponges and swabs. Our study compared efficacy of sponge swabs manufactured by 3M™ and World Bioproducts. There is a lack of research validating the best performing swab type and enrichment method combination that is sensitive when used on rough, porous surfaces. The sensitivity of these environmental sampling tools and methods are critical considerations to effectively monitor the presence of Listeria species on wooden boards used during aging of artisan cheese. Seasoned spruce wooden shelves, cut into 100cm2 replicates, were spot inoculated with varying concentrations of Listeria species inocula, the Listeria species strains consisted of two L. monocytogenes strains and a Green Florescence Protein (GFP) expressing strain of L. innocua. The inoculated wooden surface was swabbed with three environmental sampling sponge/swab formats (World Bioproducts© EZ ReachTM environmental swabs (WBEZ) with HiCap (WBHC) and Dey-Engley (WBDE) neutralizing broths; and 3MTM environmental swabs (3MTM) with Dey-Engley neutralizing broth). Enumeration methods were used to determine the low target limits of detection. Once the low target concentrations were identified, five enrichment methods consisting of 3MTM Listeria Environmental Plate, FDA, Dual Enrichment, modified USDA, and modified FDA were challenged against low concentrations of Listeria species inocula (0.01 cfu/cm2, 0.1 cfu/cm2, 1 cfu/cm2) and the three environmental sponge swab formats. Performance of the swab formats was assessed by collection of naturally contaminated environmental samples (n=405) from dairy farm environments, swabbing where wooden surfaces existed, and analyzed using the most effective enrichment methods found from previous experiments. Lastly, the wooden surfaces and sponge swabs were observed under a Florescent Microscope using GFP L. innocua to visually determine how each sponge material of the 3M™ and World Bioproducts recovered the inocula. When wood surfaces were inoculated at high concentration levels of Listeria spp., all swab formats performed equally for detecting Listeria. Success of positive recovery at low concentrations was variable, where enrichment methods and swabs were not dependent on each other. The swab format that worked best for detecting low levels of Listeria species was the WBDE sponge swab. The WBDE swab also performed the best in dairy farm environmental sampling. The m-USDA enrichment method was found to be most effective in recovery and repair of low and potentially injured Listeria spp. Wooden surfaces are rough and porous and should be taken into consideration when creating an environmental sampling plan for these food contact surfaces. All swabs and methods performed with only slight variation, but the variation could be significant when monitoring wooden shelves with low level contamination of Listeria species. Artisan cheesemakers who use wooden shelves during the aging of their cheese, should ensure use of the most sensitive detection methods.
12

Rôle de la dynamique des calottes glaciaires dans les grands changements climatiques des périodes glaciaires-interglaciaires.

Peyaud, Vincent 30 November 2006 (has links) (PDF)
Cette thèse concerne la modélisation des calottes de glace qui ont couvert l'hémisphère nord durant les dernières périodes glaciaires. Des améliorations de la physique ont été effectéees sur le modèle de calotte de glace Antarctique du LGGE, nommé GRISLI, afin de rendre ce modèle portable sur l'hémisphère nord. Une nouvelle méthode pour déterminer la position du front des ice shelves (plates-formes de glace flottante) a été mise au point, des conditions aux limites spécifiques au front des ice shelves ont été ajoutées. Un nouveau schéma pour le drainage de l'eau sous-glaciaire et un critère basé sur la pression de l'eau sous-glaciaire ont permis de localiser les ice streams (ou fleuves de glace) de façon bien plus réaliste qu'auparavant. Ce nouveau modèle est appliqué aux calottes de l'hémisphère nord et simule leur évolution lors du dernier cycle glaciaire-interglaciaire en comparant l'impact relatif du bilan de masse en surface et de la dynamique. L'évolution de la calotte eurasienne aurout de l'évènement à 90 000 ans (BP) a été détaillée pour étudier l'impact des lacs proglaciaires et le rôle des ice shelves pendant l'avancée et le retrait sur les mers de Barents et de Kara.
13

Melhoria no desempenho lumínico e energético de edifícios com prateleiras de luz

Alves Netto, Ary Rodrigues 27 April 2015 (has links)
Submitted by Bruna Rodrigues (bruna92rodrigues@yahoo.com.br) on 2016-10-03T12:43:37Z No. of bitstreams: 1 DissARAN.pdf: 5471320 bytes, checksum: 163168f02a4c2ea1b7ef6721e2c822fe (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-10T14:36:19Z (GMT) No. of bitstreams: 1 DissARAN.pdf: 5471320 bytes, checksum: 163168f02a4c2ea1b7ef6721e2c822fe (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-10T14:36:25Z (GMT) No. of bitstreams: 1 DissARAN.pdf: 5471320 bytes, checksum: 163168f02a4c2ea1b7ef6721e2c822fe (MD5) / Made available in DSpace on 2016-10-10T14:36:30Z (GMT). No. of bitstreams: 1 DissARAN.pdf: 5471320 bytes, checksum: 163168f02a4c2ea1b7ef6721e2c822fe (MD5) Previous issue date: 2015-04-27 / Não recebi financiamento / Energy consumption due to the economic development of countries impacts directly on the environment and causes investments in the power generation conventional or alternative infrastructure. Lighting systems are responsible for much of the energy consumed in buildings and in urban areas, demanding action to improve energy efficiency. The use of natural light is one of the factors that contribute most to obtain energy savings in lighting on buildings. Using natural lighting in improving the lightining performance of the building will be through the analysis of light shelves behavior, redirecting both, direct sunlight and widespread in the celestial dome for indoor environments. To analyze were made computational models of a building on UFSCar and other in IPT, using TropLux software. The simulation results indicate that the use of redirector device of natural light in buildings improves illuminance levels and their distribution in the sites studied. With the simulations results, was estimated how much can be saved in electricity that would be spent floodlit by identifying the level of energy efficiency of the studied system. / O consumo de energia decorrente do desenvolvimento econômico dos países impacta diretamente sobre o meio ambiente e provoca investimentos na infraestrutura de geração de energia seja convencional ou alternativa. Os sistemas de iluminação são os responsáveis por grande parte da energia consumida nas edificações e no meio urbano, demandando ações em prol da eficiência energética. O emprego da luz natural é um dos fatores que mais contribuem para que se obtenha economia de energia na iluminação de edifícios. Neste trabalho o uso iluminação natural na melhoria do desempenho lumínico do edifício foi por meio da análise do comportamento de prateleiras de luz, redirecionando tanto a luz direta do sol como a difundida na abóbada celeste para o interior dos ambientes. Para a análise foram feitos modelos computacionais, de um edifício da UFSCar e outro do IPT, utilizandose o programa TropLux. Os resultados das simulações dos edifícios indicam que o uso do dispositivo redirecionador da luz natural melhora os índices de iluminância e a distribuição dos mesmos nos ambientes estudados. Com os resultados das simulações, estimou-se o quanto se pode economizar de energia elétrica que seria gasta com iluminação artificial identificando-se o nível de eficiência energética do sistema estudado.
14

Řízení zásob v Sephora / Stock management in Sephora

Natokina, Marina January 2015 (has links)
The goal of this diploma thesis is, through three performance indicators: Stock Depreciation, Supplier Fill Rate and On Shelves Availability, to analyze stock management at Sephora Czech Republic, propose, implement and evaluate selected methods of improving strategy. Thematically, the thesis is divided into two parts. The first part includes theoretical background, basic concepts related to the stock and its management. The second chapter is a practical part, where the main focus is given to analysis of current state of inventory management, recommendations for improvement, their implementation and evaluation of the results.
15

Modelling and remote sensing of meltwater drainage on Antarctic ice shelves

Spergel, Julian Jacob January 2022 (has links)
In this thesis, I have used remote sensing and modeling techniques to investigate Antarctic ice shelf surface hydrology with the purpose of answering three key questions: 1) How do surface drainage systems evolve over a typical summertime melt season, over several consecutive melt seasons, and over several decades? 2) What controls the expansion of surface hydrology networks? and 3) Will surface drainage expand into areas vulnerable to hydrofracture and important for buttressing when meltwater volume increases in a warmer, future climate? In Chapter 1, our analysis of satellite observations of Amery Ice Shelf’s surface drainage networks suggests that their downstream extent varies inter-annually, that this variability is not simply the result of inter-annually variability in melt rates, and that ice-shelf topography plays a crucial role. Consecutive years of extensive melting lead to year-on-year expansion of the drainage system, potentially through a link between melt production, refreezing in firn, and the maximum extent of the lakes at the downstream termini of drainage. These mechanisms are important when evaluating the potential of drainage systems to grow in response to increased melting, delivering meltwater to areas of ice shelves vulnerable to hydrofracture. In Chapter 2, we use high resolution elevation data to delineate hydrologic catchments on Amery, Roi Baudouin, Larsen C, Nivlisen, and Riiser-Larsen Ice Shelves. We compare our results spatially with modelled present-day melt production, future melt predictions, and stress-based vulnerability to hydrofracture, to examine the controls on these hydrologically important characteristics of the topography. The high volume elevation data present computational challenges that cannot be overcome with traditional data analysis workflows. Therefore, pre-processing for catchment delineation is made possible by parallelizing these tasks with the computational power of cloud-based cluster computing. Catchments with high basin volumes are found clustered near grounding lines and nunataks, and these catchments are bordered down-glacier by broader, low volume catchments. We hypothesize that once meltwater production fills these catchments, we should expect to see overflow of meltwater, extending drainage systems downstream to the calving fronts or into areas vulnerable to hydrofracture. In Chapter 3, we use the digital elevation data from Chapter 2 as the input for an idealizedwater routing model of the eastern and western Amery Ice Shelf, Nivlisen Ice Shelf, and Roi Baudouin Ice Shelf to investigate this drainage network expansion. In our comparison with previous observational studies, we find that our modelled drainage networks show similar drainage network patterns, despite having several discrepancies in drainage network arrangement and water ponding locations. We use our model to investigate the expansion of the drainage network with average annual melt from the regional climate model RACMO. In one model run, we use the spatial distribution of average annual melt from an overlapping RACMO subset, in the other, we input a spatially-averaged melt production of the same subset of RACMO. We compare the results of these simulations to investigate if the expansion of these drainage systems is controlled predominantly by near-surface climate via water input, or if topography also plays a role. We find variability both between drainage systems and within a single drainage system, and that within all of our selected drainage systems, topography exerts some control over expansion. The responsiveness of a drainage network system to spatially variable meltwater input may affect how susceptible the system is to expansion, thus the spatial distribution of melt input must be represented in an ice shelf stability projection model. As melt input increases in a warmer future Antarctic, it will be increasingly important tounderstand how surface melting may affect ice shelf stability. This thesis shows several proof-of-concept approaches towards modelling future expansion of surface drainage networks on Antarctic ice shelves. We find that the spatial variability of melt does impact the expansion rate of drainage networks across ice shelf areas potentially vulnerable to hydrofracture. This thesis posits that with more year-on-year meltwater drainage system growth, meltwater-induced hydrofracture may become an increasingly regular occurrence on Antarctic ice shelves.
16

Assessing Perceptions and Influences to "The Most Diabetes and Health Friendly Shelves Initiative" in Choice Food Pantry Clients

Frye, Alyssa 09 July 2019 (has links)
No description available.
17

Riverine and coastal ocean contributions to the global and regional oceanic cycling of carbon and nutrients

Lacroix, Fabrice 08 July 2019 (has links) (PDF)
Les rivières sont une source importante de constituants biogéochimiques pour les océans. Jusqu’à présent, les modèles océaniques globaux représentaient de manière inadéquate ou ignoraient simplement les apports continentaux de nutriments, de carbone, d’alcalinité provenant des rivières. En particulier, les perturbations anthropiques des apports fluviaux au cours du 20 ème siècle et leurs conséquences sur l’état physique et biogéochimique des océans - notamment la zone côtière - n’ont pas encore été analysées à l’aide d’un modèle global prenant en compte la circulation tridimensionnelle de l’océan. L’objectif principal de cette thèse était donc d’intégrer les apports biogéochimiques provenant des rivières dans un modèle océanique global afin d’améliorer la compréhension du cycle du carbone de l’océan côtier et son évolution au cours du 20 ème siècle. Dans un premier temps, mon travail a visé à l’amélioration des connaissances concernant le rôle des apports biogéochimiques fluviaux sur le cycle du carbone océanique à long-terme, en se focalisant sur la période préindustrielle. Pour cela, j’ai estimé les apports des rivières en utilisant des modèles permettant d’estimer l’érosion chimique et le transfert de matière organique desécosystèmes terrestres à l’océan. Ces apports fluviaux ont ensuite été ajoutés dans le modèle biogéochimique océanique HAMOCC et leurs impacts sur la production primaire océanique et les flux de CO2 entre l’atmosphère et l’océan ont été analysés. Les résultats nous ont permis de quantifier un dégazage de CO 2 préindustriel de 0.23 Pg C yr -1 pour l’océan global, principalement localisé à proximité de l’embouchure des rivières. Le modèle a également démontré l’existence d’un transfert inter-hémisphèrique de carbone, avec un plus grand apport des rivières à l’océan dans l’hémisphère nord, et un transfert de l’hémisphère nord à l’hémisphère sud où un dégazage net se produit. Une augmentation considérable de la production primaire océanique induite par les apports des rivières a également été prédite.La modélisation biogéochimique de l’océan côtier a ensuite été améliorée, en augmentant la vitesse de minéralisation de la matière organique dans les sédiments côtiers et en incluant la dégradation de la matière organique dissoute d’origine terrestre (tDOM) dans l’océan. Par ailleurs, notre analyse suggère un temps de résidence des eaux dans la zone côtière significativement plus courte (14-16 mois en moyenne) que celui estimé jusqu’à présent (>4 ans). Ce temps de courte résidence implique un transfert efficace de matière organiquede l’océan côtier à l’océan ouvert, un état autotrophe net de l’océan côtier, ainsi qu’un puit de CO 2 (0.06-0.08 Pg C yr -1) pour la période préindustrielle, contrairement aux hypothèses précédemment proposées dans la littérature.Dans le dernier chapitre, les perturbations océaniques induites par les changements de la concentration en CO 2 dans l’atmosphère, de la physique de l’océan et des apports biogéochimiques fluviaux au cours du 20 ème siècle ont été analysées. Les résultats indiquent que la réduction de production primaire nette (NPP) observée dans les océans tropicaux et subtropicaux, pourrait être entièrement compensée par une augmentation de la NPP dans l’océan austral et dans les systèmes côtiers de type «EBUS». Les simulations montrent aussi que l’augmentation des apports fluviaux provoque une augmentation de NPP océanique à l’échelle de l’océan côtier (+15 %) et à l’échelle globale (+ 4 %). En conclusion, cette thèse a permis de démontrer l’importance d’inclure la variabilité spatio-temporelle des apports fluviaux et des processus biogéochimiques de l’océan côtier dans la description du cycle du carbone océanique global. Les améliorations apportées au modèle océanique global HAMOCC permettront d’affiner les prédictions du rôle de l’océan dans le cycle du carbone au cours du 21 ème siècle. / River deliver vast amounts of terrestrially derived compounds to the ocean. These fluxes are of particular importance for the coastal ocean, which is recognized as a region of disproportionate contribution to global oceanic biological fluxes. Until now, the riverine carbon, nutrient and alkalinity inputs have been poorly represented or omitted in global ocean biogeochemistry models. In particular, there has yet to be a model that considers the pre-industrial riverine loads of biogeochemical compounds to the ocean, and terrestrial inputs of organic matter are greatly simplified in their composition and reactivities in the ocean. Furthermore, the coastal ocean and its contribution to the globalcarbon cycle have remained enigmatic, with little attention being paid to this area of high biological productivity in global model analysis of carbon fluxes. Lastly, 20 th century perturbations in riverine fluxes as well as of the physical and biogeochemical states of the coastal ocean have remained unexplored in a 3-dimensional model. Thus, the main goals of this thesis are to integrate an improved representation of riverine supplies in a global ocean model, as well as to improve the representation of the coastal ocean in the model, in order to solve open questions with respect its global contributions to carbon cycling.In this thesis, I first aimed to close gaps of knowledge in the long-term implications of pre-industrial riverine loads for the oceanic cycling of carbon in a novel framework. I estimated pre-industrial biogeochemical riverine loads and their spatial distributions derived from Earth System Model variables while using a hierarchy of state-of-the-art weathering and organic matter land-ocean export models. I incorporated these loads into the global ocean biogeochemical model HAMOCC and investigated the induced changes in oceanic biological production and in the air-sea carbon flux, both at the global scale and in a regional shelf analysis. Finally, I summarized the results by assessing the net land sink of atmospheric carbon prescribed by the terrestrial models, and comparing it to the long-term carbon outgassing determined in the ocean model. The study reveals a pre-industrial oceanic outgassing flux of 231 Tg C yr -1 ,which is found to a large degree in proximity to the river mouths. The model also indicates an interhemispheric transfer of carbon from dominant northern hemisphere riverine inputs to outgassing in the southern hemisphere. Furthermore, I observe substantial riverine-induced increases in biological productivity in the tropical West Atlantic (+166 %), the Bay of Bengal (+377 %) and in the East China Sea (+71 %), in comparison to a model simulation which does not consider the riverine inputs.In addition to considering supplies provided by riverine fluxes, the biogeochemical representation of the coastal ocean is improved in HAMOCC, by firstly increasing organic matter remineralization rates in the coastal sediment and by secondly explicitly representing the breakdown process of terrestrial dissolved organic matter (tDOM) in the ocean. In an analysis of the coastal fluxes, the model shows a much shorter residence time of coastal waters (14-16 months) than previously assumed, which leads to an efficient cross-shelf transport of organic matter and a net autotrophic state for both the pre-industrial timeframe and the present day. The coastal ocean is also revealed as a CO2 sink for the pre-industrial time period (0.06-0.08 Pg C yr -1 ) in contrary to to the suggested source in published literature. The sink is however not only caused by the autotrophic state of the coastal ocean, but it is likely also strongly influenced by the effects of biological alkalinity production, as well as both physical and biogeochemical characteristics of open ocean inflows.In the final chapter, 20 th century oceanic perturbations due to changes in atmospheric CO 2 concentrations and in the physical climate, and to increases in riverine nutrient supplies were investigated by using sequential model simulations. The model results show that the decrease in the net primary production (NPP) in the tropical and subtropical oceans due to temperature-induced stratification may be completely compensated by increases in the Southern Ocean and in Eastern Boundary Upwelling Systems (EBUS). The model also reveals that including increases in riverine supplies causes a global ocean NPP increase of +4 %, with the coastal ocean being a particularlystrongly affected region (+15 %).This thesis shows a strong necessity to represent spatio-temporal changes in riverine supplies and of the coastal ocean state in spatially explicit global models in order to assess changes of the global cycling of carbon in the ocean in the past and potentially in the future. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
18

A Numerical Model Investigation of the Role of the Glacier Bed in Regulating Grounding Line Retreat of Thwaites Glacier, West Antarctica

Waibel, Michael Scott 20 March 2017 (has links)
I examine how two different realizations of bed morphology affect Thwaites Glacier response to ocean warming through the initiation of marine ice sheet instability and associated grounding line retreat. A state of the art numerical ice sheet model is used for this purpose. The bed configurations used are the 1-km resolution interpolated BEDMAP2 bed and a higher-resolution conditional simulation produced by John Goff at the University of Texas using the same underlying data. The model is forced using a slow ramp approach, where melt of ice on the floating side of the grounding line is increased over time, which gently nudges the glacier toward instability. Once an instability is initiated, the anomalous forcing is turned off, and further grounding line retreat is tracked. Two model experiments are conducted. The first experiment examines the effect of different anomalous forcing magnitudes over the same bed. The second experiment compares the generation and progress of instabilities over different beds. Two fundamental conclusions emerge from these experiments. First, different bed geometries require different ocean forcings to generate a genuine instability, where ice dynamics lead to a positive feedback and grounding line retreat becomes unstable. Second, slightly different forcings produce different retreat rates, even after the anomalous forcing is shut off, because different forcing magnitudes produce different driving stresses at the time the instability is initiated. While variability in the retreat rate over time depends on bed topography, the rate itself is set by the magnitude of the forcing. This signals the importance of correct knowledge of both bed shape and ocean circulation under floating portions of Antarctic ice sheets. The experiments also imply that different ocean warming rates delivered by different global warming scenarios directly affects the rate of Antarctic contribution to sea level rise.
19

Optimalizace skladového systému ve vybraném výrobním podniku / Optimization of the warehouse system in the selected production plant

KOVÁŘOVÁ, Zuzana January 2017 (has links)
The aim of the diploma thesis was optimization of the warehouse system according to suitability for use in assortment in a selected production company focusing on material and information flows, decay processes, warehouse technology, logistic costs and relevant logistics indicators. The partial objective was to determine the critical factors in terms of management and operation in the warehouse of the selected manufacturing enterprise.
20

A New Method for Melt Detection on Antarctic Ice-Shelves and Scatterometer Calibration Verification

Kunz, Lukas Brad 28 July 2004 (has links) (PDF)
Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat scatterometer and microwave radiometer measurements from the Special Sensor Microwave/Imager (SSM/I) are used to determine periods of surface melt and freeze in the Antarctic ice-shelves. The normalized radar backscatter (sigma-0) and backscatter polarization ratio (PR) are used in the maximum likelihood estimation of the ice-state. This method is used to infer the daily ice-surface conditions for 25 selected study points located on the Ronne, Ross, Larsen, Fimbul, Amery, and Shackleton Ice-shelves. The temporal and spatial variations of the radar response are also observed for various neighborhood sizes surrounding each given point during the study period. Criteria for determining the dates of melt-onset and freeze-up for each Austral summer are also presented. Validation of the ice-state and melt-onset date estimates is performed by analyzing corresponding brightness temperature (Tb) measurements from radiometers. QuikScat sigma-0 measurements from 1999 through 2003 are analyzed and it is shown that Ku-band scatterometers are very useful for determining periods of melt in Antarctic ice-sheets and provide high temporal and spatial resolution ice-state estimates. These estimates can be important for long-term studies of the climatic effects of the seasonal and inter-annual melting of the Antarctic ice-sheets. The SeaWinds on QuikScat (QuikScat) and SeaWinds on ADEOS-2 (SeaWinds) scatterometers are identical radar sensors on different spaceborne platforms traversing similar orbits. QuikSCAT and SeaWinds data are used to infer near-surface wind vectors, polar sea-ice extent, polar-ice melt events, among others. In order to verify the relative calibration of these two sensors a simple cross-calibration method is implemented based on land measurements. A first-order polynomial model for the incidence angle dependence of sigma-0 is used to account for biases in the sigma-0 measurements. This model is applied to selected regions of the Amazon rainforest and the Sahara desert. It is shown that the two sensors are well calibrated. Additionally, evidence of a previously presumed diurnal cycle in the Amazon rainforest backscatter is given.

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