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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.
21

Compartmental Process-based Model for Estimating Ammonia Emission from Stored Scraped Liquid Dairy Manure

Karunarathne, Sampath Ashoka 06 July 2017 (has links)
The biogeochemical processes responsible for production and emission of ammonia from stored liquid dairy manure are governed by environmental factors (e.g. manure temperature, moisture) and manure characteristics (e.g. total ammoniacal nitrogen concentration, pH). These environmental factors and manure characteristics vary spatially as a result of spatially heterogeneous physical, chemical, and biological properties of manure. Existing process-based models used for estimating ammonia emission consider stored manure as a homogeneous system and do not consider these spatial variations leading to inaccurate estimations. In this study, a one-dimensional compartmental biogeochemical model was developed to (i) estimate spatial variation of temperature and substrate concentration (ii) estimate spatial variations and rates of biogeochemical processes, and (iii) estimate production and emission of ammonia from stored scraped liquid dairy manure. A one-dimension compartmentalized modeling approach was used whereby manure storage is partitioned into several sections in vertical domain assuming that the conditions are spatially uniform within the horizontal domain. Spatial variation of temperature and substrate concentration were estimated using established principles of heat and mass transfer. Pertinent biogeochemical processes were assigned to each compartment to estimate the production and emission of ammonia. Model performance was conducted using experimental data obtained from National Air Emissions Monitoring Study conducted by the United States Environmental Protection Agency. A sensitivity analysis was performed and air temperature, manure pH, wind speed, and manure total ammoniacal nitrogen concentration were identified as the most sensitive model inputs. The model was used to estimate ammonia emission from a liquid dairy manure storage of a dairy farm located in Rockingham and Franklin counties in Virginia. Ammonia emission was estimated under different management and weather scenarios: two different manure storage periods from November to April and May to October using historical weather data of the two counties. Results suggest greater ammonia emissions and manure nitrogen loss for the manure storage period in warm season from May to October compared to the storage period in cold season from November to April. / Ph. D.
22

Interna flöden och processer på Å&R Carton : processbaserad verksamhetsanalys och förbättringsförslag för ledtidsreduktion / Internal Processes at Å&R Carton : Process Based Analys and Proposals to Reduce Time in the Supply Chain

Gustafson, Anders January 2003 (has links)
<p>Denna rapport syftar till att, på Å&R Carton i Norrköping, analysera de interna flödena och processerna samt ge förslag på hur ledtider ska kunna reduceras väsentligt. Ett sätt att uppfylla syftet är att dela in verksamheten i processer genom olika metoder och kriterier förprocessbestämning. Valda metoder i rapporten är; kvalitativ ansats med hög validitet och reliabilitet, processbaserad verksamhetsanalys och procedurbeskrivning. </p><p>Genom omfattande litteraturstudier, insamlande av data i form av intervjuer, benchmarking, platsundersökningar och interna dokument har nulägesmodeller arbetats fram. Analysen av dessa visar bland annat på att såväl planeringsprocessen som inköpsprocessen idag inte fungerar värdeadderande och bör ses över. Därutöver finns också andra processer som bidrar till ett komplext flöde. Dessa behöver effektiviseras eller ändras för att korta ledtider. Vidare visar analysen på att en omfattande attitydsundersökning behövs, dels för att komma till rätta med vissa stämningar och dels för att på sikt skapa en effektiv arbetsmiljö. </p><p>Till förbättringsförslagen hör, förutom en attitydsundersökning, förslaget att utarbeta tydliga mål och strategier. Sedan måste dessa kommuniceras till samtliga anställda, till exempel genom arbetsgrupper. Vidare föreslås att Å&R Carton tittar på automatisk datafångst som ett mycket kostnadseffektivt sätt att kontrollera det totala flödet. På lång sikt bör också företaget titta på att implementera processorientering. Dock behöver företaget först och främst se till att skapa en förändringsvillig attityd för att nå framgång i sitt effektiviseringsarbete. Slutsatsen blir att Å&R Carton har stor potential att väsentligt förkorta sina ledtider om företaget hanterar situationen rätt. För att lyckas kan delar av denna rapport användas där det viktigaste är att en engagerad ledning visar vägen. </p> / <p>The purpose of this final thesis is to analyse the internal processes at Å&R Carton in Norrköping and give proposals to reduce time in the Supply Chain. One way to fulfill the purpose is to use Process Based Analys and split the organisation in different processes. Process Based Models have then been constructed by studying litterature, benchmarking, internal documents and making a lot of interviews. The analys shows that different processes must be changed to make the flow through the Supply Chain more efficient. The analys give us also recommendations like attitude investigations and implementation of ECR. The conclusion is that Å&R Carton have great potential to reduce time in the Supply Chain if the management are active, follow the recommendations and show the employees the way about.</p>
23

Interna flöden och processer på Å&amp;R Carton : processbaserad verksamhetsanalys och förbättringsförslag för ledtidsreduktion / Internal Processes at Å&amp;R Carton : Process Based Analys and Proposals to Reduce Time in the Supply Chain

Gustafson, Anders January 2003 (has links)
Denna rapport syftar till att, på Å&amp;R Carton i Norrköping, analysera de interna flödena och processerna samt ge förslag på hur ledtider ska kunna reduceras väsentligt. Ett sätt att uppfylla syftet är att dela in verksamheten i processer genom olika metoder och kriterier förprocessbestämning. Valda metoder i rapporten är; kvalitativ ansats med hög validitet och reliabilitet, processbaserad verksamhetsanalys och procedurbeskrivning. Genom omfattande litteraturstudier, insamlande av data i form av intervjuer, benchmarking, platsundersökningar och interna dokument har nulägesmodeller arbetats fram. Analysen av dessa visar bland annat på att såväl planeringsprocessen som inköpsprocessen idag inte fungerar värdeadderande och bör ses över. Därutöver finns också andra processer som bidrar till ett komplext flöde. Dessa behöver effektiviseras eller ändras för att korta ledtider. Vidare visar analysen på att en omfattande attitydsundersökning behövs, dels för att komma till rätta med vissa stämningar och dels för att på sikt skapa en effektiv arbetsmiljö. Till förbättringsförslagen hör, förutom en attitydsundersökning, förslaget att utarbeta tydliga mål och strategier. Sedan måste dessa kommuniceras till samtliga anställda, till exempel genom arbetsgrupper. Vidare föreslås att Å&amp;R Carton tittar på automatisk datafångst som ett mycket kostnadseffektivt sätt att kontrollera det totala flödet. På lång sikt bör också företaget titta på att implementera processorientering. Dock behöver företaget först och främst se till att skapa en förändringsvillig attityd för att nå framgång i sitt effektiviseringsarbete. Slutsatsen blir att Å&amp;R Carton har stor potential att väsentligt förkorta sina ledtider om företaget hanterar situationen rätt. För att lyckas kan delar av denna rapport användas där det viktigaste är att en engagerad ledning visar vägen. / The purpose of this final thesis is to analyse the internal processes at Å&amp;R Carton in Norrköping and give proposals to reduce time in the Supply Chain. One way to fulfill the purpose is to use Process Based Analys and split the organisation in different processes. Process Based Models have then been constructed by studying litterature, benchmarking, internal documents and making a lot of interviews. The analys shows that different processes must be changed to make the flow through the Supply Chain more efficient. The analys give us also recommendations like attitude investigations and implementation of ECR. The conclusion is that Å&amp;R Carton have great potential to reduce time in the Supply Chain if the management are active, follow the recommendations and show the employees the way about.
24

Developing a product costing model using Process-Based Cost Modeling : A case study of early stage cost estimation in a multinational agricultural cooperative

Eriksson, Alexander January 2018 (has links)
Product costing can be used to estimate potential future costs and revenues associated with a product. In the development of new products early cost estimates can be used to support decision making regarding which products are worth pursuing, and which production processes that are the most profitable. For a firm to make precise early cost estimates both technical and financial expertise is needed; however, in practice there is generally a gap between technology and cost. Process-Based Cost Modeling (PBCM) is a model developed to address this gap and generate costing estimates of higher precision. The model is especially developed for process production technologies. Although promising, PBCM is under researched and its applicability in new contexts are yet to be explored.  The purpose of this study was to explore the PBCM’s applicability in new context of process production. This was done through a case study at a multinational agricultural cooperative. The problematization presented by the Case Company was to make early cost estimation of the production process of a main product and its byproducts. Furthermore, the Case Company wanted to compare alternative production designs and use of different raw materials in the production process. To create a product costing model that fully captures the contextual depth of the problem both qualitative and quantitative data was gathered from internal documents, a series of interviews, and observation of one of the sub-processes.  The findings of the study resulted in development of a batch costing model, a hybrid between continuous operations and order costing systems. The batch costing proved to be dynamic and allowed comparison of different production and raw material alternatives. Furthermore, the PBCM methodology that resulted in the batch costing model was evident to give a deeper contextual understanding of the relationship between cost and production technology. For the Case Company, the outcome of the study highlighted key areas needing further investigation and process design features that lower operational costs. The results also provide recommendations how to increase the precision of the product costing models when more data are available. Finally, the academic outcome of the thesis provides trajectory in the further research on PBCM and gives new perspective on the use of batch costing in continuous operations. / Produktkalkylering kan användas för att uppskatta framtida kostnader och intäkter associerade med en produkt. Vid utveckling av nya produkter och produktionsprocess kan produktkalkylering således användas vid beslutsfattande i situationer där man ska välja vilka produkter som är värda att arbeta vidare med, och vid lönsamhetsberäkningar vid olika tillverkningsprocesser. För att företaget ska kunna göra precisa kostnadsuppskattningar behövs både teknisk och ekonomisk expertis. Detta överses dock ofta i praktiken, vilket leder till en klyfta mellan teknik och kostnad. Processbaserad kostnadsmodellering, eller Process-Based Cost Modeling (PBCM), är en metod som har tagits fram för att överkomma denna klyfta, framförallt inom processproduktion. Även om modellen är lovande så saknas forskning på området, därav behöver PBCM:s applicerbarhet prövas i nya kontexter. Syftet med denna studie var att undersöka PBCM:s applicerbarhet i en ny kontext inom processproduktion. Detta gjordes genom att genomföra en fallstudie på ett multinationellt lantbruksföretag som har verksamhet inom livsmedelproduktion. Fallföretags problematisering byggde på att de ville göra en tidig kostnadsbedömning på tillverkningsprocess som producerar en huvudprodukt och ett antal biprodukter. Tillverkningsprocessen är ännu inte utvecklad och företaget vill således jämföra produktionskostnader vid användning av olika råmaterial och tillverkningsalternativ. För att utveckla en lämplig produktkalkyl till företaget samlades både kvalitativa och kvantitativa data in genom interna dokument, en serie av intervjuer, samt genom observation av en av de underliggande tillverkningsprocesserna. Studien resulterade i en hybridkalkyl som använder sig av både process- och orderkalkylering. Hybridkalkylen visade sig lämplig både för företagets produktionsteknologi, men framförallt tillät jämförelse mellan olika tillverkningsalternativ. Metodiken hos PBCM visade sig även användbar för att förstå hur kostnaden påverkas av produktionsteknologin. För fallföretaget påvisade resultaten områden som behöver undersökas ytterligare. Det ges även rekommendationer hur hybridkalkylen kan finslipas när företaget har mer data tillgängligt. När det kommer till det akademiska bidraget, så ger rapporten riktning för fortsatta forskningen på PBCM och ger nya perspektiv på hur hybridkalkylering kan användas i processproduktion.
25

Estimation of N2O and CO2 emissions from organic and N fertilizers by coupling field measurements with modelling analysis

CHIAZZESE, MURJAL 28 May 2015 (has links)
L'effetto dei gas serra sul cambiamento climatico ha portato molti esperti a considerare la riduzione delle emissioni di gas serra come strategia per il riscaldamento globale. In particolare tale fenomeno è causato dall’anidride carbonica (CO2), metano (CH4) e il protossido di azoto (N2O). E 'ampiamente accettato che la principale fonte antropica di gas a effetto serra (tranne CO2) è dovuta alle attività agricole. Lo scopo di questo studio è quello di definire concetti e strumenti per facilitare il settore agricolo a ridurre le emissioni di gas serra. In particolare, abbiamo posto la nostra attenzione ai sistemi di misurazione delle emissioni dal suolo, testando un nuovo sistema (SASSFlux) e le sue caratteristiche a confronto con due strumenti ampiamente utilizzati (Bruel & Kjaer e gascromatografia). Inoltre abbiamo testato due modelli di simulazione (DNDC e SPACSYS) valutando i dati simulati e quelli misurati su un esperimento effettuato su lisimetri. In fine abbiamo applicato le conoscenze acquisite in pieno campo per la valutazione delle emissioni di CO2 e N2O con diversi concimi e lavorazione del terreno. La tesi si propone di fornire una visione completa dei diversi aspetti da affrontare nella valutazione delle emissioni di gas serra provenienti da diversi scenari di gestione agricola. / The effect of greenhouse gases (GHG) on climate change led many experts to consider the reduction of GHGs emissions as a crucial strategy to tackle the predicted global warming. In particular, atmospheric warming is caused mainly by carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). It is widely accepted that the main anthropogenic source of GHG (except CO2) is due to agriculture activities. The purpose of this study was to help define concepts and tools to facilitate agricultural sector to reduce greenhouse gas emissions. In particular we based our focus on measuring systems for CO2 emissions, testing the performance of novel system (SASSFlux) and its features in different condition with two widely used instruments (Bruel&Kjaer and gas chromatography). Moreover we testing two process-based models, DNDC and SPACSYS, evaluating their performance and the agreement between simulated and measured data on a experiment carried out on lysimeters. At the end we applied all the knowledge acquired on a field experiment evaluating CO2 and N2O emissions from different organic and mineral fertilizers and tillage. The complete thesis aims to provide a comprehensive view of the different aspects to be addressed in the assessment of GHG emissions from different scenarios of agricultural management.
26

Groundwater vulnerability assessment using process-based models

Lindström, Riitta January 2005 (has links)
<p>The focus of this thesis is on groundwater vulnerability assessment by process-based simulation models and data acquisition for these assessments. A modelling system for intrinsic groundwater vulnerability assessment in water supply areas was developed, consisting of flow- and transport models for the unsaturated zone and the groundwater zone, coupled to a geographical informa-tion system. The system was applied to a water supply area located close to a major road south of Stockholm. Chloride was used as an indicator in determining the vulnerability for groundwater contamination from the road. The approach was useful to illustrate the dynamic change of chlo-ride concentrations both during the stage of continuous application and after the applications was terminated. A structure and content of a database for flow and transport modelling, based on hydrogeological environments, was outlined. An existing hydrogeological parameter database, HPAR at the Geological Survey of Sweden (SGU), was examined as a potential source of data for the new database. Values for some important parameters needed for groundwater modelling, such as hydraulic conductivity and effective porosity, were lacking in the three municipal HPAR databases that were studied. It was suggested that these data should be added, together with information on the hydrogeological environments, for all geographical positions of interest. Without such minimum information, the efficient use of modelling tools could not be expected.</p><p>Typical profiles of three common Swedish hydrogeological environments (sand deposits, glacial till and clay covered areas) were used to represent generic input data to model simulations in the unsaturated zone so that the importance of soil, vegetation type and groundwater levels on turn-over times of conservative contaminants transported by natural recharge could be examined. The same profiles were used to predict the penetration depth of accidental liquid spills that occur at the land surface level. In the case of contaminant transport by natural recharge, water storage in the soil profile and vegetation type played an important role for turnover times. For liquid spills, the hydraulic con-ductivity was found to be of major importance, while the water retention properties were of less importance. Modelling, together with available data sources, were successfully used to demon-strate the vulnerability of different environmental conditions.</p>
27

FACTS OF THE IMAGINATION (FROM THE INSIDE OUT)

Iglesias, Janelle Ann 01 January 2006 (has links)
Growing up in a bicultural household, navigating the F train as well as mountain creeks, studying culture and then participating in its production, these are some of the idiosyncrasies that I bring to my work. My investigations are rooted in combining a rediscovery of the sensuousness of the natural world and an investigation of the poetics of everyday life. Choosing materials and situations within the realm of the everyday, I'm interested in a transformation that suggests the infinite potential and worth in all things. The resulting objects have identities as complex as my own. They are ridiculous and serious, normal and magical, and confident in their awkwardness. This document was created in Microsoft Word X for mac.
28

Sur le conditionnement des 
modèles génétiques de réservoirs chenalisés méandriformes à des données de puits / On the conditioning of 
process-based channelized meandering reservoir models on well data

Bubnova, Anna 11 December 2018 (has links)
Les modèles génétiques de réservoirs sont construits par la simulation des principaux processus de sédimentation dans le temps. En particulier, les modèles tridimensionnels de systèmes chenalisés méandriformes peuvent être construits à partir de trois processus principaux : la migration du chenal, l’aggradation du système et les avulsions, comme c’est réalisé dans le logiciel Flumy pour les environnements fluviatiles. Pour une utilisation opérationnelle, par exemple la simulation d'écoulements, ces simulations doivent être conditionnées aux données d'exploration disponibles (diagraphie de puits, sismique, …). Le travail présenté ici, basé largement sur des développements antérieurs, se concentre sur le conditionnement du modèle Flumy aux données de puits.Deux questions principales ont été examinées au cours de cette thèse. La première concerne la reproduction des données connues aux emplacements des puits. Cela se fait actuellement par une procédure de "conditionnement dynamique" qui consiste à adapter les processus du modèle pendant le déroulement de la simulation. Par exemple, le dépôt de sable aux emplacements de puits est favorisé, lorsque cela est souhaité, par une adaptation des processus de migration ou d'avulsion. Cependant, la manière dont les processus sont adaptés peut générer des effets indésirables et réduire le réalisme du modèle. Une étude approfondie a été réalisée afin d'identifier et d'analyser les impacts indésirables du conditionnement dynamique. Les impacts ont été observés à la fois à l'emplacement des puits et dans tout le modèle de blocs. Des développements ont été réalisés pour améliorer les algorithmes existants.La deuxième question concerne la détermination des paramètres d’entrée du modèle, qui doivent être cohérents avec les données de puits. Un outil spécial est intégré à Flumy - le "Non-Expert User Calculator" (Nexus) - qui permet de définir les paramètres de simulation à partir de trois paramètres clés : la proportion de sable, la profondeur maximale du chenal et l’extension latérale des corps sableux. Cependant, les réservoirs naturels comprennent souvent plusieurs unités stratigraphiques ayant leurs propres caractéristiques géologiques. L'identification de telles unités dans le domaine étudié est d'une importance primordiale avant de lancer une simulation conditionnelle avec des paramètres cohérents pour chaque unité. Une nouvelle méthode de détermination des unités stratigraphiques optimales à partir des données de puits est proposée. Elle est basée sur la Classification géostatistique hiérarchique appliquée à la courbe de proportion verticale (VPC) globale des puits. Les unités stratigraphiques ont pu être détectées à partir d'exemples de données synthétiques et de données de terrain, même lorsque la VPC globale des puits n'était pas visuellement représentative. / Process-based reservoir models are generated by the simulation of the main sedimentation processes in time. In particular, three-dimensional models of meandering channelized systems can be constructed from three main processes: migration of the channel, aggradation of the system and avulsions, as it is performed in Flumy software for fluvial environments. For an operational use, for instance flow simulation, these simulations need to be conditioned to available exploration data (well logging, seismic, …). The work presented here, largely based on previous developments, focuses on the conditioning of the Flumy model to well data.Two main questions have been considered during this thesis. The major one concerns the reproduction of known data at well locations. This is currently done by a "dynamic conditioning" procedure which consists in adapting the model processes while the simulation is running. For instance, the deposition of sand at well locations is favored, when desired, by an adaptation of migration or avulsion processes. However, the way the processes are adapted may generate undesirable effects and could reduce the model realism. A thorough study has been conducted in order to identify and analyze undesirable impacts of the dynamic conditioning. Such impacts were observed to be present both at the location of wells and throughout the block model. Developments have been made in order to improve the existing algorithms.The second question is related to the determination of the input model parameters, which should be consistent with the well data. A special tool is integrated in Flumy – the Non Expert User calculator (Nexus) – which permits to define the simulation parameters set from three key parameters: the sand proportion, the channel maximum depth and the sandbodies lateral extension. However, natural reservoirs often consist in several stratigraphic units with their own geological characteristics. The identification of such units within the studied domain is of prime importance before running a conditional simulation, with consistent parameters for each unit. A new method for determining optimal stratigraphic units from well data is proposed. It is based on the Hierarchical Geostatistical Clustering applied to the well global Vertical Proportion Curve (VPC). Stratigraphic units could be detected from synthetic and field data cases, even when the global well VPC was not visually representative.
29

The development of a process-based management system at Almedahls AB

Rehbein, Marina, Rosendahl, Johan, Reza Saeedfar, Amir January 2010 (has links)
“To develop a process-based management system at a textile company” is the title of this thesis.The thesis is a compulsory part of the master programme: Quality and environmental management at Högskolan i Borås, the master programme is worth 60 ECTS credits. It has been carried out as an interdisciplinary project between students of the School of Engineering as well as the Textile School in Borås.Almedahls is a textile company located in Kinna, Sweden. They are in a need of process-based management system for their four different strategic business areas and three companies.The purpose of the thesis is not only to develop a process-based management system for Almedahl-Kinna, which is one of the three companies, but also to create the new management system in order for it to work for all three parts of the company in the future.The theory used in this project focuses on the definition of business process mapping as well as its application in use. The theory also includes process-based management systems, business process management and measurements.The theory and interviews with the employees at Almedahl-Kinna can be considered as the foundation of the result of this thesis. Result of the thesis is a shared process-based management system for Almedahl-Kinna developed in a business process map.The result also consists of sub-processes linked to the core process of the BPM. The sub-process is based on the inputs and outputs found in the core process.A common vision between Almedahls and the study group was essential to achieve an acceptable result in the end, hence the project was driven by an initial BPM provided by Almedahls and in fact it became one of the main aims of this project: how to change the management’s point of view towards thinking in processes?Based on the nature of process-based management systems, the idea to choose this system was correctly selected for Almedahls to gather all four strategy business areas and three companies together.
30

Groundwater vulnerability assessment using process-based models

Lindström, Riitta January 2005 (has links)
The focus of this thesis is on groundwater vulnerability assessment by process-based simulation models and data acquisition for these assessments. A modelling system for intrinsic groundwater vulnerability assessment in water supply areas was developed, consisting of flow- and transport models for the unsaturated zone and the groundwater zone, coupled to a geographical informa-tion system. The system was applied to a water supply area located close to a major road south of Stockholm. Chloride was used as an indicator in determining the vulnerability for groundwater contamination from the road. The approach was useful to illustrate the dynamic change of chlo-ride concentrations both during the stage of continuous application and after the applications was terminated. A structure and content of a database for flow and transport modelling, based on hydrogeological environments, was outlined. An existing hydrogeological parameter database, HPAR at the Geological Survey of Sweden (SGU), was examined as a potential source of data for the new database. Values for some important parameters needed for groundwater modelling, such as hydraulic conductivity and effective porosity, were lacking in the three municipal HPAR databases that were studied. It was suggested that these data should be added, together with information on the hydrogeological environments, for all geographical positions of interest. Without such minimum information, the efficient use of modelling tools could not be expected. Typical profiles of three common Swedish hydrogeological environments (sand deposits, glacial till and clay covered areas) were used to represent generic input data to model simulations in the unsaturated zone so that the importance of soil, vegetation type and groundwater levels on turn-over times of conservative contaminants transported by natural recharge could be examined. The same profiles were used to predict the penetration depth of accidental liquid spills that occur at the land surface level. In the case of contaminant transport by natural recharge, water storage in the soil profile and vegetation type played an important role for turnover times. For liquid spills, the hydraulic con-ductivity was found to be of major importance, while the water retention properties were of less importance. Modelling, together with available data sources, were successfully used to demon-strate the vulnerability of different environmental conditions. / QC 20101020

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