Academic literature on the topic 'Modelli processo carbonio'
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Journal articles on the topic "Modelli processo carbonio"
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Riad, Nacera, Naima Bouzidi, Mohamed Reda Zahi, Ouassila Touafek, Yasmina Daghbouche, Louis Piovetti, and Mohamed El Hattab. "Extraction of the Volatile Oils of Dictyopteris membranacea Batters 1902 by Focused Microwave-assisted Hydrodistillation and Supercritical Carbon Dioxide: Empirical Kinetic Modelling Approach, Apparent Solubility and Rate Constants." Chemical and Biochemical Engineering Quarterly, no. 3 (October 20, 2021). http://dx.doi.org/10.15255/cabeq.2020.1885.
Full textDissertations / Theses on the topic "Modelli processo carbonio"
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Coslovich, Davide. "Stima del sequestro potenziale di carbonio nei suoli agricoli del Veneto con il GEFSOC modellyng system." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4597.
Full textAbstract:
2009/2010I suoli globalmente contengono circa 2500 Pg di C in forma minerale ed organica (ca 1550 Pg) ed il flusso annuo da e verso l’atmosfera – che attualmente contiene circa 760 Pg C – coinvolge circa 120 Pg di C. Questi scambi di carbonio sono clima-dipendenti; l’effetto del cambiamento climatico sui depositi di carbonio del suolo è perciò di importanza critica, in quanto anche piccole variazioni di un deposito di tale entità possono determinare importanti conseguenze sulla concentrazione di anidride carbonica in atmosfera, innescando meccanismi retroattivi positivi. Per fare delle previsioni sui cambiamenti dei depositi di carbonio per effetto dei cambiamenti climatici o di altre variabili è neccesario ricorrere a dei modelli; in particolare, per le stime a scala nazionale e regionale si impiegano dei modelli che operano a livello di ecosistema e che vengono abbinati a dei SIT. Vista la forte sinergia con la mitigazione e adattamento ai cambiamenti climatici, la ricerca è stata volta a stimare il potenziale di sequestro e accumulo di sostanza organica nei terreni agricoli del Veneto, con un occhio di riguardo per la gestione sostenibile. In secondo luogo, a fornire uno strumento per la contabilizzazione del sequestro di carbonio nei sistemi agricoli. Si è individuato nel GEFSOC Modelling Sistem uno strumento idoneo per il perseguimento di questi obiettivi; il GEFSOC MS integra due modelli meccanicistici ampiamente sperimentati – Century e RothC – ed il metodo empirico dell’IPCC e li interfaccia con un SOTER-DB e con un GIS. L’uso e la gestione del suolo ed i loro cambiamenti sono variabili fondamentali nel determinare il contenuto di carbonio nei depositi del terreno; poiché manifestano i loro effetti anche secoli dopo che si sono verificati, è necessario ricostruire la loro storia almeno negli ultimi 100 anni. Nel corso della ricerca è stato ideato e sperimentato per la prima volta in questo settore un approccio spazialmente esplicito alle transizioni di uso e gestione del suolo, utilizzando materiale cartografico di varia natura e completando la raccolta dati con statistiche agrarie e fonti storiche. Le simulazioni sono state fatte contemplando due diversi scenari di cambiamento climatico (PCM-B1 e Had3A1FI) spinti fino al 2100. L’analisi dei risultati prodotti evidenzia che i terreni più ricchi in carbonio sono maggiormente soggetti a perdite, mentre quelli poveri, anche se in misura modesta, incrementano il loro contenuto; la tendenza, quindi, è di avvicinarsi ad una maggiore omogeneità. Per quel che riguarda gli usi del suolo, seminativi ed aree agricole eterogenee sono le categorie che hanno manifestato tassi di incremento superiori. I tassi di variazione, comunque, sono tendenzialmente in calo e, per lo scenario di cambiamento climatico meno marcato, ad un certo punto (2070 ca) si portano su valori negativi: questo fatto si ripercuote sui depositi del terreno, che complessivamente mostrano un incremento nel lungo periodo, ma via via più contenuto, fino a raggiungere un massimo e quindi cominciare ad emettere negli ultimi decenni della simulazione. I depositi dei terreni sottoposti allo scenario di cambiamento più marcato, invece, non hanno subito flessioni ed hanno garantito, anche se in misura calante, il sequestro lungo tutto il periodo della simulazione. Questo dato può essere di qualche interesse nello studio degli effetti della temperatura sul rapporto produzione di biomassa-accumulo/decomposizione. L’analisi delle mappe dei depositi e dei tassi di variazione annua ad ettaro prodotte con la sperimentazione, ed il confronto delle stesse con carte del contenuto del carbonio nei terreni di doversa origine e natura, rivelano l’utilità dell’approccio spazialmente esplicito nella definizione delle transizioni dell’uso e gestione del suolo; è possibile infatti riconoscere, dalla zonizzazione, i tematismi che possono avere avuto un peso preponderante nel determinare peculiari situazioni; questo consente di indagarle, verificare la validità delle assunzioni fatte in fase di progettazione, modificare eventualmente la parametrizzazione e reindirizzare le simulazioni. Ad una livello di risoluzione comparabile a quello degli strati informativi di partenza. Alla luce della sperimentazione effettuata, si ritiene che il GEFSOC Modelling System meriti grande considerazione per quanto attiene la contabilizzazione del carbonio nei sistemi agricoli – problematica inevasa fino ad oggi in Italia; quale strumento a supporto del processo decisionale; per le possibili sinergie nella pianificazione di campionamenti e sperimentazioni attinenti; per l’approfondimento della ricerca nell’ambito delle relazioni tra clima e suolo.
XXIII Ciclo
1970
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Nocerino, Vincenzo. "Attività preliminari allo sviluppo di un modello matematico per il processo di pellettizzazione e di essiccamento del nero di carbonio." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Find full textAbstract:
Gli impianti dell’industria di processo, durante il loro funzionamento, devono soddisfare requisiti relativi alla quantità realizzata ed alla qualità del prodotto finito. Nell’ottica del miglioramento continuo, l’ottimizzazione dei processi mira ad aumentare la produzione e/o la qualità del prodotto finito al fine di ottenere il massimo profitto.
Il presente elaborato di tesi è stato sviluppato durante un tirocinio
svolto presso il sito produttivo di Cabot Italiana. Esso ha avuto come obiettivo l’analisi dei dati di processo di un impianto dello
stabilimento al fine di una loro migliore comprensione e
dell’individuazione di correlazioni esistenti tra i dati stessi,
indispensabile punto di partenza per lo sviluppo futuro di un modello matematico che possa prevedere il comportamento del sistema studiato e contribuire a miglioramenti del suo sistema di controllo.
Il lavoro di tesi si articola in 7 capitoli. Il capitolo 1 è finalizzato alla presentazione sommaria dell’attività di tesi. Il capitolo 2 tratta in via generale i metodi di analisi dei dati, con un approfondimento sulle principali tecniche di pretrattamento dei dati e sull’Analisi delle Componenti Principali (PCA – Principal Component Analysis). Il capitolo 3 descrive la realtà di Cabot Italiana e ,nel dettaglio, la seconda parte della linea di processo 2 con il relativo sistema di controllo, che rappresenta il caso di studio considerato nel presente elaborato di tesi. Il capitolo 4 si focalizza sul metodo di gestione dei dati di processo, in particolare sui 2 software utilizzati nello stabilimento di Cabot Italiana: Aspen Process Explorer e AEMS Capability. Il capitolo 5 è interamente dedicato al pretrattamento dei dati di processo per il caso di studio considerato. Il capitolo 6 descrive l’applicazione della Principal Component Analysis al caso di studio.
Infine, nel capitolo 7 sono riportate le considerazioni conclusive.
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Guillemot, Joannès. "Productivity and carbon allocation in European forests : a process-based modelling approach." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112091/document.
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Les processus physiologiques déterminant la productivité forestière and l’allocation du carbone (C) entre les différents organes de l’arbre restent mal connus. La croissance forestière a longtemps été considérée comme limitée par le C, à travers un lien causal entre photosynthèse et croissance (contrôle de la croissance par la source de C). Ce paradigme C-centré est à l’origine des règles gouvernant l’allocation du C dans la plupart des modèles à base de processus (MBP). Cependant, le contrôle de la croissance forestière par la source de C a été remis en cause par un certain nombre d’études mettant en lumière que l’activité des méristèmes est plus sensible aux stress environnementaux (stress hydrique, température basse) que ne l’est l’assimilation du C (contrôle de la croissance par l’activité du puits). De plus, l’effet de la gestion, qui influe fortement sur le fonctionnement de la forêt and sa croissance, n’est pas pris en compte dans la plupart des MBP utilisés pour projeter le futur puits de C terrestre. Notre objectif principal dans cette thèse est d’améliorer notre connaissance des contraintes qui affectent - ou affecteront- la productivité ligneuse des forêts européennes, depuis l’époque actuelle jusqu’à la fin du 21ème siècle. Nous avons abordé cet objectif à travers l’amélioration du modèle CASTANEA, sur la base d’une analyse détaillée des déterminants de la productivité ligneuse annuelle des forêts françaises sur les 30 dernières années. Les espèces étudiées sont Fagus sylvatica, Quercus ilex, Quercus petraea, Quercus robur et Picea abies. Nos résultats suggèrent que la croissance annuelle des espèces étudiées est soumise à un contrôle complexe, impliquant des limitations par la source de C et par l’activité du puits. La variabilité inter-site de la fraction de C allouée à la croissance est principalement expliquée par un déclin lié à l’âge. La croissance annuelle à l’échelle de l’arbre est bien prédite par la taille des individus. Nous avons montré que l’asymétrie de la croissance, i.e., l’avantage des gros arbres dans la compétition pour les ressources, augmente avec la productivité, aux échelles inter-site et inter-annuelle. Sur la base de ces résultats, nous avons développé un nouveau schéma d’allocation du C dans le modèle CASTANEA. Le nouveau modèle a été capable de reproduire de manière satisfaisante la variabilité inter-annuelle et inter-site dans la croissance ligneuse aérienne le long de gradients environnementaux à l’échelle nationale. Le modèle a également été validé en utilisant une méta-analyse de mesure de réserves carbonées et des estimations satellitaires d’indices foliaires. Nos résultats indiquent que la représentation du contrôle de la croissance par l’activité du puits n’affecte pas les prédictions qualitatives de l’évolution de la productivité forestière européenne précédemment obtenues par les MBP C-centrés. Cependant, les MBP C-centrés sous-estiment certainement l’hétérogénéité spatiale des effets du changement climatique.Nous avons enfin utilisé notre nouvelle connaissance des déterminants de la croissance ligneuse annuelle à l’échelle de l’arbre (i.e., les règles empiriques de la compétition) pour calibrer un module simulant la croissance individuelle dans CASTANEA. Le modèle couplé a été utilisé pour évaluer l’effet potentiel de la gestion sur le fonctionnement des forêts et la croissance ligneuse à l’échelle de la France. Nous avons identifié les zones où la gestion pourrait être intensifiée pour réduire l’impact du changement climatique sur la productivité forestière nationale. Environ un quart des forêts françaises en hêtre et chênes tempérés sont en zone de forte vulnérabilité, zone dans laquelle la gestion pourrait donc être utilisée à profit pour limiter l’impact du changement climatique sur la récolte de boisThe processes that underlie forest productivity and C allocation dynamics in trees are still poorly understood. Forest growth has for long been thought to be C limited, through a hypothesized causal link between C supply and growth (source control). This C-centric paradigm underlies most of the C allocation rules formalized in process-based models (PBMs). However, the source limitation of growth has been questioned by several authors, arguing that meristem activities are more sensitive than C assimilation to environmental stresses (e.g., water deficit and low temperatures). Moreover, the effect of management, which strongly affects forest functioning and wood growth, is not accounted for in most of the PBMs used to project the future terrestrial C sink. Our main objective in this thesis was to move forward into our understanding of the constraints that affect - or will affect - the wood productivity in European forests, from present to the end of the 21 st century. We addressed this objective through the improvement of the representation of the forest productivity and C allocation in the CASTANEA PBM, building on a detailed analysis of the key drivers of annual wood productivity in French forests over the last 30 years (the species studied are Fagus sylvatica, Quercus ilex, Quercus petraea, Quercus robur and Picea abies). Our results supported the premise that the annual wood growth of the studied species is under a complex control including both source and sink limitations. The inter-site variability in the fraction of C allocatedto stand wood growth was predominantly driven by an age-related decline. At the tree level, we showed that annual wood growth was well predicted by the individual size. The size-asymmetry of growth, i.e., the advantage of big trees in the competition for resources, increased consistently with the whole stand productivity at both inter-site and inter-annual scales. On the basis of our findings, we developed a new C allocation scheme in the CASTANEA PBM, which integrate a combined source-sink limitation of wood growth. The new calibrated model captured both the inter-annual and inter-site changes in stand wood growth that was observed across national environmental gradients. The model was also successfully evaluated against a meta-analysis of carbohydrate reserve pools in trees and satellite-derived leaf area index estimates. Our results indicated that the representation of the environmental control of sink activity does not affect the qualitative predictions of the future of the European forest productivity previously obtained from source-driven PBMs. However, the current, source-driven generation of PBMs probably underestimates the spatial heterogeneity of the effects of climate change on forest growth that arise from sink limitations.Further, we successfully used our findings regarding the dependences of annual wood growth at tree level (i.e., empirical rules of tree growth competition) to calibrate a module for the simulation of the individual growth of trees in the CASTANEA model. The coupled model was used to assess the potential effects of management on forest functioning and wood growth across France. We identified the areas where management efforts may be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield
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Stachiw, Rosalvo. "Modelagem e simulação do processo de adsorção de compostos orgânicos em xisto, catalisador exaurido de FCC e carvão ativado em pó." Universidade Tecnológica Federal do Paraná, 2008. http://repositorio.utfpr.edu.br/jspui/handle/1/135.
Full textAbstract:
O alto custo do carvão ativado tem motivado a busca por materiais adsorvedores de baixo custo, como os subprodutos industriais. Neste sentido, o uso dos subprodutos industriais de xisto: finos de xisto (XC), xisto retortado (XR) e xisto retortado com pneus (XRP), proveniente do processo PETROSIX/PETROBRAS, e o catalisador exaurido (CAT), da unidade de FCC (Craqueamento Catalítico em Leito Fluidizado), foram caracterizados e utilizados neste trabalho na adsorção de compostos orgânicos de efluente líquido industrial. O objetivo geral deste estudo é modelar matematicamente o processo de adsorção de compostos orgânicos em xisto, catalisador exaurido de FCC e carvão ativado em pó, utilizando o modelo HSDM (Modelo de Difusão por Superfície Homogênea), e o comportamento hidráulico do sistema adsorvedor. A caracterização estrutural e química de várias amostras de xisto (finos de xisto, xisto retortado e xisto retortado com pneus) e do catalisador exaurido de FCC, além do desenvolvimento de um modelo computacional para a simulação do processo de adsorção são contribuições adicionais ao trabalho. Os resultados de caracterização dos adsorventes de xisto mostram que estes materiais são basicamente macroporosos e com área superficial em torno de 0,51 a 3,36 2 . 1 m g , além de apresentarem as mesmas estruturas cristalinas, e micrografias características dos argilominerais. Já o adsorvente CAT mostrou-se formado basicamente por faujasita, sílica e alumina, apresentando-se na forma de grânulos esféricos, irregulares e microporosos, com área superficial característica de materiais zeolíticos (148 e 155 2 . 1 m g ). Os ensaios de adsorção realizados nos efluentes sintéticos e industriais (Fenólico e Petroquímico) mostraram que existe potencial de aplicação dos subprodutos industriais de xisto e CAT na remoção de compostos orgânicos (corantes, fenóis e COT) destes efluentes. Os resultados das simulações obtidos do modelo proposto mostraram que o tratamento unicamente por adsorção em xisto ou CAT, tendo em vista os padrões ambientais de descarte de efluente (resolução CONAMA 357), é inviável. Isto por que a quantidade de adsorvente requerida é muito elevada. Entretanto, tais adsorventes podem ser utilizados na redução da carga orgânica de ambos os efluentes. Por questões de transporte, é indicado que cada subproduto industrial seja utilizado na própria indústria que lhe deu origem. Ou seja, o CAT é indicado para o tratamento do efluente Petroquímico e os adsorventes de xisto para o Fenólico.The high cost of the activated carbon has motivated the search of low cost adsorbents such as industrial by-products. In this sense, the use of industrial by-products of oil shale: Oil Shale (XC), Pirolized Oil Shale (XR) and Pirolized Oil Shale with Tires (XRP), from PETROSIX/PETROBRAS, and the spent catalyst (CAT), from FCC (Fluid Catalytic Cracking) unit were characterized and used in this work in the adsorption of organics compounds of industrial liquid effluent. The main contribution of this thesis is to propose a mathematical model to the adsorption process of organic compounds in oil shale, spent catalyst of FCC and powdered activated carbon. This model is based on HSDM (Homogeneous Surface Diffusion Model) model and on the hydraulic behavior of the adsorbent system. Other contribution is the structural and chemical characterization of several samples of oil shale (oil shale, Pirolized oil shale and Pirolized oil shale with Tires) and of the spent catalyst of FCC. A computational model to simulate the adsorption process of these materials is also developed and can be considered an additional contribution of this work. Experimental and simulated results allow characterization of the oil shale adsorbent as basically macroporous and with superficial area about 0.51 to 3.36 m2.g-1. In addition, they present the same crystal structures and clay micrografies characteristics. The adsorbent CAT is composed basically by Faujasite, silica and alumina. They present spherical beads, irregular forms and micropores, with superficial area characteristics of zeolitic materials (148 and 155 m2.g-1). The adsorption tests realized in the synthetic and industrial effluents (Phenolic and Petrochemical) showed the potential of application of the industrial by-products of oil shale and CAT in the removal of organics compounds (dyes, Phenol and COT) of these effluents. In respect of environmental standards to effluents disposal (CONAMA resolution 357), simulations results, obtained with the proposed model, has demonstrated that the use of only oil shale or CAT is not viable, because the high quantity of adsorbents required. However, such adsorbents can be used in the reduction of organic loads in both effluents, when combined with other processes. Each adsorbent showed be used where it is produced because of transportation cost. The CAT is indicated for the treatment of Petrochemical effluent while the others adsorbents may be applied in the phenolic effluent treatment.
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Ma, Yuxin. "Empirical and Mechanistic Modelling for Process Understanding in Digital Soil Mapping." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21413.
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Empirical prediction of soil properties coupled with an understanding of soil processes, can uncover the complexity of the soil system. Digital soil mapping (DSM) has revolutionized the way soil information is delivered. While empirical DSM has greatly improved the quantitative prediction, we should be able to incorporate our physical and mechanistic understanding of the processes. Likewise, we should be able to use empirical knowledge to inform process-based models. This thesis delivers mechanistic and empirical models to improve the understanding of soil genesis and mapping of soil functional properties and finding the relationships between soil and environmental factors. Chapter 2 first critically reviews pedology models and DSM concepts, mapping soil classes, mapping soil profiles, mapping pedological features and processes, the relation between pedological knowledge and DSM, and the application of mechanistic pedological models in DSM. Chapter 3 investigates the use of a mechanistic pedogenesis model, State Space Soil Production and Assessment Model (SSSPAM) for modelling the spatiotemporal evolution of particle-size distribution (PSD). In Chapter 4, we used process-based understanding in a mechanistic model to help us make a better prediction of the 4D spatiotemporal distribution of SOC. Chapter 5 evaluates the proposition that soil properties can be evaluated at any depth by comparing the multi-layered 2.5D and 3D modelling with soil depth as a predictor variable. Chapter 6 investigates whether data provided from a rapid and non-destructive proximal sensor can be used to directly predict the provenance of soil samples. Overall, this thesis demonstrates that to comprehensively explain the complexity of the soils, their dynamics and relation to the soil-forming factors, it is beneficial to include knowledge of processes to model soil profile distribution and identify the unique pattern of soil distribution.
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Erland, Samuel. "Characterisation of uncured carbon fibre composites." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715265.
Full textAbstract:
The weight saving benefits of carbon fibre composites have been keenly adopted by civil aviation, with over 50% of the weight of modern designs coming from the carbon fibre components. The rapid rise in demand for this new material has led to the development of fully automated manufacturing techniques, improving rate of production and repeatability of manufacture. However, this rapid development, combined with a constant drive for increased rate of manufacture from industry can result in the formation of critical defects in the more complicated structural components. Manufacturing complex aeronautical structures from carbon fibre leads to a number of interesting mechanical problems. Forcing a multi-layered laminate to conform to a curved geometry requires individual layers to move relative to one another in order to relieve various forming-induced stresses. If the layers are constrained the dissipation of these stresses in the form of interply shear is prevented and a wide range of defects can occur, compromising the integrity of the final component. One of the most important of these is fibre wrinkling, which is effectively the buckling of one or more layers within an uncured laminate. This buckle results in a localised change in fibre orientation, which can result in a significant knockdown in part strength. A large amount of research has been conducted on carbon fibre in its cured state, when it exists as elastic fibres in an elastic matrix. Manufacturing occurs when the material is uncured however, with modern processes typically using fibres which are pre-impregnated with resin in order to reduce void content and aid fibre placement. A ply of uncured material therefore consists of stiff elastic fibres suspended in a very weak liquid viscoelastic material, whose properties are hugely influenced by temperature and rate of deformation. This thesis builds a better understanding of the mechanics involved in forming, using a series of characterisation techniques developed drawing from techniques in the literature. Part of the process involves the fitting of a one-dimensional viscoelasto-plastic model to experimental test data in order to represent the material response when shearing two plies about their interface. This model shows the material response to be dominated by the viscoelastic resin at low temperatures, before becoming frictional and fibre dominated at higher temperatures. In terms of optimum formability, a region exists in the transition from the viscous to frictional behaviour at which resistance to forming is minimised. With this data alone, optimum forming parameters such as rate of deformation, pressure and temperature can be suggested based on the material being used, along with design parameters such as stacking sequence. Another important characteristic which must be understood when considering ply wrinkling is the bending stiffness of uncured prepreg, both as a single ply and when combined to form a small laminate. A wrinkle is in effect the buckling of a single or small number of plies within a laminate, therefore by understanding the bending stiffness and process-induced loading we can begin to predict whether or not wrinkles are likely to occur for a particular manufacturing regime. In order to assess bending stiffness, a modified Dynamic Mechanical Analysis process is employed, replacing the standard Engineers Bending Theory calculations with a Timoshenko element to capture the large degree of intraply shear experienced in the bending of uncured prepreg. Finally, a small laminate scale demonstrator is considered in which a 24-ply laminate is consolidated into a female tool in such a way as to induced maximum shear strain between the plies, in order that the optimum forming parameters predicted by the characterisation tests might be validated. A simple energy minimisation model is used to predict the variation in consolidation strain around the part due to resistance to shear, using material parameters from the model describing the inter-ply shear test data. These parameters are also used to inform a novel modelling technique which has been developed parallel to this thesis, which is validated against the experimental results, and shows how the characterisation techniques can be used to advance simulation methods aimed at reducing the development time for new carbon fibre components. This work provides a set of tests and methodologies for the accurate characterisation of the behaviour of uncured carbon fibre during forming. The models developed alongside these tests allow for a detailed interrogation of the results, providing valuable insight into the mechanics behind the observed material behaviour and enabling informed decisions to be made regarding the forming process in order that the occurrence of defects might be minimised. The primary aim has been to provide a set of vital input parameters for novel, complex process modelling techniques under development, which has been achieved and validated experimentally.
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Hidalgo, Durán Felipe Antonio. "Caracterización y cuantificación de los procesos de transporte-reacción que dominan la dinámica intradiaria de dióxido de carbono y oxígeno en el Salar del Huasco." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/150693.
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Ingeniero CivilLos salares se ubican típicamente en la región altiplánica andina de Chile, Perú y Bolivia. Los sistemas acuáticos formados en ellos, corresponden usualmente a lagunas extremadamente someras, sometidas a condiciones ambientales desfavorables como bajo oxígeno atmosférico, alta oscilación térmica, alta radiación y fuertes vientos durante las horas del día. Estos ecosistemas están principalmente sustentados por la producción bentónica primaria, la que funciona como alimento para aves de la zona, como los flamencos, ave que se encuentra en estado vulnerable. Debido a lo anterior es que el trabajo de título realizado, consiste en la elaboración de un modelo hidrodinámico de la variación intradiaria de dióxido de carbono y oxígeno en el salar de Huasco, dinámicas que se ven afectadas por los flujos en la interfaz agua-sedimentos, los procesos biológicos de la columna de agua y los flujos en la interfaz aire-agua. El objetivo general es describir y cuantificar los procesos de transporte-reacción de dióxido de carbono y oxígeno en la zona, mediante la elaboración de un modelo hidrodinámico impermanente en 0D del salar, que permita obtener las evoluciones diarias para el oxígeno y el dióxido de carbono, para luego ser validado utilizando mediciones del terreno. El fin de la modelación es adquirir conocimiento acerca de estos fenómenos que pueden afectar considerablemente a los ecosistemas de la zona, únicos en el mundo, adaptados a condiciones climáticas extremas. Inicialmente se realizó un procesamiento de los datos obtenidos en dos campañas de terreno realizadas en los años 2015 y 2016, el que complementado con una revisión bibliográfica orientada a la hidro y biodinámica de sistemas someros, permitió plantear un modelo conceptual que simula las evoluciones intradiarias de dióxido de carbono y oxígeno. Luego se procedió a calibrar y validar el modelo con datos medidos, para finalmente realizar un análisis de sensibilidad que explique los procesos y parámetros más significativos del modelo. El principal resultado del trabajo, corresponde a un modelo que permite cuantificar las variaciones intradiarias de dióxido de carbono y oxígeno. Este modelo permite identificar que los procesos más importantes para el salar corresponden a la producción primaria, y a los flujos de masa en la interfaz aire-agua, tanto para el dióxido de carbono como para el oxígeno. En estos flujos se presentan inconsistencias entre lo que se sabe de la literatura y lo que se observa en el modelo, donde se presentan grandes diferencias entre las tasas de trasferencia en esta interfaz según el compuesto que se esté analizando.
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Wu, Tao. "Tooling performance in micro milling : modelling, simulation and experimental study." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/7211.
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With the continuing trend towards miniaturization, micro milling plays an increasingly important role in fabrication of freeform and high-accuracy micro parts or components directly and cost-effectively. The technology is in kinematics scaled down from the conventional milling, however, existing knowledge and experiences are limited and comprehensive studies on the micro tooling performance are essential and much needed particularly for the process planning and optimization. The cutting performance of micro tools is largely dependent on the dynamic performance of machine tools, tooling characteristics, work material properties and process conditions, and the latter three aspects will be focused in the study. The state of the art of micro milling technology with respect to the tooling performance has been critically reviewed, together with modelling work for performance prediction as well as metrology and instrumentation for the performance characterization. A novel 3D finite element method taking into account the geometry of a micro tool, including the tool diameter, rake angle, relief angle, cutting edge radius and helix angle, has been proposed for modelling and simulation of the micro milling process. Validation through well-designed micro milling trials demonstrates that the approach is capable of characterizing the milling process effectively. With the support of FEM simulation developed, the tooling geometrical effects, including those from helix angle, rake angle and cutting edge radius with influences on cutting forces, tool stresses, tool temperatures, milling chip formation and temperatures have been comprehensively studied and compared for potential micro tool design and optimization purposes. In an effort to prolong the tool life and enhance the tooling efficiency, DLC and NCD coatings have been deposited on micro end mills by PE-CVD and HF-CVD processes respectively. Corresponding cutting performance of these coated tools have been assessed and compared with those of WC micro tools in both dry and wet cutting conditions so as for better understanding of the coating influence on micro tools. Furthermore, the cutting characteristics of the DLC coated and uncoated tools have been analysed through verified plane-strain simulations. The effects of coating friction coefficient, coating thickness and UCT have been determined and evaluated by design of simulation method. Mechanical, chemical and physical properties of a work material have a direct influence on its micro-machinability. Five most common engineering materials including Al 6061-T6, C101, AISI 1045, 304 and P20, have been experimentally investigated and their micro milling behaviours in terms of the cutting forces, tool wear, surface roughness, and micro-burr formation have been compared and characterized. Feed rate, cutting speed and axial depth of cut constitute the complete set of process variables and they have significant effects on the tooling performance. Fundamental understanding of their influences is essential for production engineers to determine optimum cutting parameters so as to achieve the maximum extension of the tool life. 3D FE-based simulations have been carried out to predict the process variable effects on the cutting forces, tool stresses, tool temperatures as well as micro milling chip formation and temperatures. Furthermore, experimental approach has been adopted for the surface roughness characterization. Suggestions on selecting practical cutting variables have been provided in light of the results obtained. Conclusions with respect to the holistic investigation on the tooling performance in micro milling have been drawn based on the research objectives achieved. Recommendations for future work have been pointed out particularly for further future research in the research area.
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Souza, Anderson Gomes. "Modelagem e simulação do processo de absorção reativa de CO2 em modulos de membrana." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266198.
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Orientadores: Teresa Massako Kakuta Ravagnani, Sergio Persio RavagnaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A redução dos níveis de dióxido de carbono (CO2) é de suma importância, tanto para o combate à poluição atmosférica proveniente de atividades industriais, como no tratamento de correntes gasosas em processos químicos. O método clássico para captura de CO2 engloba sua absorção reativa em solução de aminas, conduzida em colunas de borbulhamento, spray ou recheio. Porém, desvantagens como a formação de espuma e dispersão de fase constituem problemas operacionais significativos desses processos. Alternativamente, módulos de membrana de fibras ocas seriam equipamentos mais adequados para esse fim, apresentando como vantagens uma grande área interfacial e flexibilidade operacional. Nesse sentido, o presente estudo buscou realizar a simulação do processo de absorção de CO2 em módulos de membrana, utilizando soluções aquosas de2-amino-2-metil-1-propanol (AMP), dietanolamina (DEA) e metildietanolamina (MDEA). A modelagem matemática do sistema utilizou expressões da taxa de reação e equações de balanço de massa diferenciais. A resolução numérico-computacional do modelo foi conduzida mediante aplicação dos métodos de colocação ortogonal e de Michelsen, tendo sido implementada em linguagem Fortran. O processo foi estudado em diversas condições operacionais para a análise de sensibilidade paramétrica e os resultados indicam, com base nas características dos diferentes sistemas, as melhores condições gerais de operação. Dentre as aminas consideradas como solventes reativos, as maiores taxas de absorção de CO2 foram previstas com o uso de AMP. Entretanto, sua concentração radial, à saída do módulo de membrana, apresentou forte incidência do fenômeno de depleção da solução absorvedora. Os principais parâmetros que incrementaram a taxa de absorção e, conseqüentemente, a eficiência do módulo de membrana, foram a velocidade de escoamento do líquido absorvente, as concentrações iniciais de CO2 e de amina, o raio interno e o comprimento das fibras.
Abstract: The decrease in the carbon dioxide (CO2) levels is extremely important to avoid atmospheric pollution, from industrial activities, and to the gaseous treatment in several chemical processes. The classical process to the CO2 sequestration involves its reactive absorption into amine solutions, which are carried on bubble, spray or fixed bed columns. However, some disadvantages, such as foam formation and phase dispersion, are serious operational problems to be avoided. Alternatively, membrane modules are supposed to be mode adequate equipments to that aim, which some advantages are great interfacial area and operational flexibility. Under this context, the present study intended to provide the simulation of the CO2 absorption process in hollow fiber membrane module, by using a-amino-2-methyl-1-propanol (AMP), diethanolamine (DEA) and methyldiethanoamine (MDEA) aqueous solutions. The mathematical modeling is based on the inherent rate expressions of the reactive system, besides the differential mass balance equations. The numerical and computational solution was developed by applying the orthogonal collocation and Michelsen methods, which were compiled in Fortran language. The idealized process was studied based on a given standard operational condition, besides a parametric sensibility analysis. The main results, to each sorption system, show the best general conditions to the process operation. Under the standard operation, among the alkanolamines considered as reactive solvents, the best CO2 absorption rate were calculated by using the AMP solution. Nevertheless, its radial concentration tends to suffer the incidence of depletion phenomena in their aqueous solution. The best performance credited to the AMP solution were also confirmed, where the main parameters that increased the absorption rate were the absorbent liquid flow velocity, the initial CO2 and amine concentration, the fibers inner radius and length.
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química
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Bandera, Beatrice. "Implementazione di processi funzionali ad uno studio LCA applicato ad un servizio di pulizia in ottica di etichettatura ecologica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/22061/.
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La metodologia LCA rappresenta lo strumento chiave delle politiche europee per la valutazione degli impatti ambientali di prodotti e servizi durante il loro intero ciclo di vita. Essa è ampiamente impiegata, tra l’altro, per la valutazione dei servizi professionali di pulizia per questo motivo sono state elaborate delle linee guida (Product Category Rules, PCR) specifiche.
Il principale obiettivo della tesi è l’elaborazione di un modello analitico per la valutazione del ciclo di vita del servizio di pulizia professionale svolto presso il Politecnico di Torino. Il modello è stato realizzato per valutare e confrontare gli impatti derivanti da tre possibili scenari di miglioramento del servizio elaborati in ottica Ecolabel. Il secondo obiettivo della tesi è testare l’adeguatezza del modello tramite sua implementazione nel software GaBi con i dati relativi al servizio in esame.
La struttura del modello è basata sulla letteratura di riferimento (PCR di settore e EPD di servizi di pulizia) ma viene adattata alle esigenze dello studio a supporto del processo di sostituzione della fornitura secondo i protocolli Ecolabel. Il servizio è diviso in tre fasi: processi di upstream, core e downstream, rispettivamente riguardanti la produzione e il trasporto degli articoli di pulizia, l’erogazione del servizio e il fine vita dei prodotti impiegati. I processi inclusi nel modello sono stati selezionati perché influenzati da una variazione del protocollo di pulizia.
I risultati ottenuti dallo studio sono relativi alla categoria d’impatto "Riscaldamento globale con orizzonte temporale di 100 anni (GWP100)" e risultano coerenti con la letteratura: la fase di maggior impatto è quella di core, seguita da upstream e poi downstream. Il modello risulta dunque idoneo all’obiettivo dello studio. Le fasi successive del progetto, escluse dall’elaborato, prevedono l’impiego del modello come base per lo svolgimento della LCA degli scenari Ecolabel, garantendo un solido confronto tra risultati.
Books on the topic "Modelli processo carbonio"
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Office, General Accounting. Air pollution: EPA's process for planning, budgeting, and reviewing research : briefing report to the chairman, Subcommittee on Oversight and Investigations, Committee on Energy and Commerce, House of Representatives. Washington, D.C: The Office, 1987.
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Office, General Accounting. Air pollution: EPA's process for planning, budgeting, and reviewing research : briefing report to the chairman, Subcommittee on Oversight and Investigations, Committee on Energy and Commerce, House of Representatives. Washington, D.C: The Office, 1987.
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Berner, Robert A. The Phanerozoic Carbon Cycle. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195173338.001.0001.
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The term "carbon cycle" is normally thought to mean those processes that govern the present-day transfer of carbon between life, the atmosphere, and the oceans. This book describes another carbon cycle, one which operates over millions of years and involves the transfer of carbon between rocks and the combination of life, the atmosphere, and the oceans. The weathering of silicate and carbonate rocks and ancient sedimentary organic matter (including recent, large-scale human-induced burning of fossil fuels), the burial of organic matter and carbonate minerals in sediments, and volcanic degassing of carbon dioxide contribute to this cycle. In The Phanerozoic Carbon Cycle, Robert Berner shows how carbon cycle models can be used to calculate levels of atmospheric CO2 and O2 over Phanerozoic time, the past 550 million years, and how results compare with independent methods. His analysis has implications for such disparate subjects as the evolution of land plants, the presence of giant ancient insects, the role of tectonics in paleoclimate, and the current debate over global warming and greenhouse gases
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Process Integration Approaches to Planning Carbon Management Networks. Taylor & Francis Group, 2020.
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Foo, Dominic C. Y., and Raymond R. Tan. Process Integration Approaches to Planning Carbon Management Networks. Taylor & Francis Group, 2020.
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Foo, Dominic C. Y., and Raymond R. Tan. Process Integration Approaches to Planning Carbon Management Networks. Taylor & Francis Group, 2020.
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Foo, Dominic C. Y., and Raymond R. Tan. Process Integration Approaches to Planning Carbon Management Networks. Taylor & Francis Group, 2020.
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Foo, Dominic C. Y., and Raymond R. Tan. Process Integration Approaches to Planning Carbon Management Networks. Taylor & Francis Group, 2020.
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Humphreys, John, and Sally Little, eds. Challenges in Estuarine and Coastal Science. Pelagic Publishing, 2022. http://dx.doi.org/10.53061/bdix4458.
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Estuarine and coastal waters are acknowledged centres for anthropogenic impacts. Superimposed on the complex natural interactions between land, rivers and sea are the myriad consequences of human activity – a spectrum ranging from locally polluting effluents to some of the severest consequences of global climate change. For practitioners, academics and students in the field of coastal science and policy, this book examines and exemplifies current and future challenges: from upper estuaries to open coasts and adjacent seas; from tropical to temperate latitudes; from Europe to Australia. This authoritative volume marks the 50th anniversary of the Estuarine and Coastal Sciences Association, and contains a prologue by founding member Professor Richard Barnes and a short history of the Association. Individual chapters then address coastal erosion and deposition; open shores to estuaries and deltas; marine plastics; coastal squeeze and habitat loss; tidal freshwaters – saline incursion and estuarine squeeze; restoration management using remote data collection; carbon storage; species distribution and non-natives; shorebirds; Modelling environmental change; physical processes such as sediments and modelling; sea level rise and estuarine tidal dynamics; estuaries as fish nurseries; policy versus reality in coastal conservation; developments in Estuarine, coastal and marine management.
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Thompson, William R., and Leila Zakhirova. Denouement: World Politics, Systemic Leadership, and Climate Change. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190699680.003.0013.
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In this final chapter, we conclude by recapitulating our argument and evidence. One goal of this work has been to improve our understanding of the patterns underlying the evolution of world politics over the past one thousand years. How did we get to where we are now? Where and when did the “modern” world begin? How did we shift from a primarily agrarian economy to a primarily industrial one? How did these changes shape world politics? A related goal was to examine more closely the factors that led to the most serious attempts by states to break free of agrarian constraints. We developed an interactive model of the factors that we thought were most likely to be significant. Finally, a third goal was to examine the linkages between the systemic leadership that emerged from these historical processes and the global warming crisis of the twenty-first century. Climate change means that the traditional energy platforms for system leadership—coal, petroleum, and natural gas—have become counterproductive. The ultimate irony is that we thought that the harnessing of carbon fuels made us invulnerable to climate fluctuations, while the exact opposite turns out to be true. The more carbon fuels are consumed, the greater the damage done to the atmosphere. In many respects, the competition for systemic leadership generated this problem. Yet it is unclear whether systemic leadership will be up to the task of resolving it.
Book chapters on the topic "Modelli processo carbonio"
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Wei, Liang, John D. Marshall, and J. Renée Brooks. "Process-Based Ecophysiological Models of Tree-Ring Stable Isotopes." In Stable Isotopes in Tree Rings, 737–56. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_26.
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AbstractTree-ring stable isotopes can be used to parameterizeprocess-based models by providing long-term data on tree physiological processes on annual or finer time steps. They can also be used to test process-based ecophysiological models for the assumptions, hypotheses, and simplifications embedded within them. However, numerous physiological and biophysical processes influence the stable carbon (δ13C) and oxygen (δ18O) isotopes in tree rings, so the models must simplify how they represent some of these processes to be useful. Which simplifications are appropriate depends on the application to which the model is applied. Fortunately, water and carbon fluxes represented in process-based models often have strong isotopic effects that are recorded in tree-ring signals. In this chapter, we review the status of several tree-ring δ13C and δ18O models simulating processes for trees, stands, catchments, and ecosystems. This review is intended to highlight the structural differences among models with varied objectives and to provide examples of the valuable insights that can come from combining process modeling with tree-ring stable isotope data. We urge that simple stable isotope algorithms be added to any forest model with a process representation of photosynthesis and transpiration as a strict test of model structure and an effective means to constrain the models.
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Tao, Feng, and Yiqi Luo. "PROcess-Guided Deep Learning and DAta-Driven Modelling (PRODA)." In Land Carbon Cycle Modeling, 319–28. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9780429155659-47.
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Raven, John A. "Carbon: A Phycocentric View." In Towards a Model of Ocean Biogeochemical Processes, 123–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_6.
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Thingstad, T. Frede. "Microbial Processes and the Biological Carbon Pump." In Towards a Model of Ocean Biogeochemical Processes, 193–208. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_9.
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Moloney, Colleen L., and John G. Field. "Modelling Carbon and Nitrogen Flows in a Microbial Plankton Community." In Protozoa and Their Role in Marine Processes, 443–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-73181-5_26.
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Deppner, H. G., and G. Schulz-Ekloff. "Modelling and Simulation of the Methanation from Carbon Monoxide-Rich Synthesis Gas." In Analysis and Control of Industrial Processes, 137–44. Wiesbaden: Vieweg+Teubner Verlag, 1991. http://dx.doi.org/10.1007/978-3-322-88847-1_11.
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Fang, Y., Z. D. Ma, and Y. Z. Luo. "Carbon Emission Modelling for Construction Logistics Process Through Activity-Based Method." In Proceedings of the 21st International Symposium on Advancement of Construction Management and Real Estate, 413–24. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-6190-5_37.
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Yi, Xiao-Su, Lie Shen, and Yi Pan. "A Model-Based Approach for Determination of Product-Properties on Carbon-Black Loaded Polyethylenes." In Microstructures, Mechanical Properties and Processes - Computer Simulation and Modelling, 236–42. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527606157.ch38.
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Wang, Weihua, Changwen Ma, Shiwen Wang, Jian Cao, Jingqi Cai, and Jianguo Lin. "An Approach for Modelling Carbon Homogenization Processes of Steel in Micro-Scale." In PRICM, 3081–90. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118792148.ch380.
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Wang, Weihua, Changwen Ma, Shiwen Wang, Jian Cao, Jingqi Cai, and Jianguo Lin. "An Approach for Modelling Carbon Homogenization Processes of Steel in Micro-Scale." In Proceedings of the 8th Pacific Rim International Congress on Advanced Materials and Processing, 3081–90. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-48764-9_380.
Full textConference papers on the topic "Modelli processo carbonio"
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Jie, Chao, Lan Zhang, and Dongya Zhao. "BP and L-S based process simulation of carbon dioxide capture." In 2014 6th International Conference on Modelling, Identification and Control (ICMIC). IEEE, 2014. http://dx.doi.org/10.1109/icmic.2014.7020777.
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Turban, G. "Gas phase and surface modelling of diamond-like carbon deposition reactors." In IEE Colloquium on `Applications of Plasma Technology to Surface Processing - Recent Developments in Modelling and Diagnostics for Process Control and Optimization'. IEE, 1995. http://dx.doi.org/10.1049/ic:19950905.
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Ostrogorsky, A. G., and L. R. Glicksman. "Radiative Heat Transfer During Growth of Carbon Nanotubes by Vertical Electric-Arc Process." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72781.
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A macroscopic finite elements model of heat transfer occurring during production of carbon nanotubes was developed. Radiation heat transfer was modeled using the Discrete Ordinates (DO) model and the Rosseland diffusion approximation. The arc is modeled as semitransparent, with the optical thickness ranging from zero to infinity. The results are compared to the limited data available. The optical thickens has a significant impact on the temperature field in (i) the arc and (ii) the anode surfaces exposed to the arc. The temperature of the cathode side-surface on which the small diameter carbon nanotube grew, is not sensitive to the optical thickness of the arc. The model indicates that the optical thickness of the arc should be high, aL ≥ 100.
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Daugevičius, Mykolas, Juozas Valivonis, and Tomas Skuturna. "The numerical analysis of the long-term behaviour of the reinforced concrete beams strengthened with carbon fiber reinforced polymer: Deflection." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.009.
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The numerical analysis of the reinforced concrete beams strengthened with CFRP is presented. The beams previously tested experimentally under long-term loading are selected for numerical simulation. The numerical modelling is performed by evaluating the beam’s work at various stages: the work stage before the long-term loading period, the work stage under the long-term load action, the work stage when the external load is removed and the work stage until failure. The work stages of all modelled beams are described in more detail. To analyse the behaviour of beams at different work stages, the numerical modelling using the phase analysis is performed. Different finite element groups are evaluated in each phase of analysis. The external load is increased, maintained and reduced. The finite elements of the CFRP layer are activated at a certain work stage for evaluating the strengthening effect. To assess the accuracy of the numerical analysis, each beam is modelled from the finite elements of various sizes. The paper presents the process of the numerical modelling and the predicted deflections. The numerically predicted deflections are compared with the deflections of the experimental study. The modelling of the behaviour of the strengthened beams has shown that the nature of the long-term deflection differs from that obtained in the experiment. The increment of the numerically predicted deflection decreases gradually over the long-term period. Meanwhile, the experimental long-term deflection increment is characterised by the sharp increase and decrease at the start of the long-term period. This contradiction shows that the experimental long-term deflections are greater. However, over time, the numerical model deflections may reach and exceed the experimental deflections due to steady increase. The smaller size of the finite elements causes the increase in the cracking moment and the higher moment when the yielding of the tensioned reinforcement occurs. However, the cracking moment obtained by the numerical modelling is much higher than that obtained by the experimental modelling. However, when the yielding strength of the tensile reinforcement is reached, the considered moment is smaller than the experimental one.
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Lasne, Patrice, Philippe Bristiel, and Nicolas Poulain. "Numerical Simulation of Full Carburizing Process of an Automotive Gear." In HT2021. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.ht2021exabp0071.
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Abstract The objective of the paper is to present material and numerical models needed to simulate with accuracy the full carburizing process of an automotive gear. The rough dimensions of the gear studied are 120mm in diameter and 45mm in height. From a numerical standpoint, as the carburizing affects only a thin layer under the surface, the mesh discretization must be adapted. Consequently, anisotropic mesh is used to describe accurately this zone. The temporal discretization must be also adapted to follow carbon diffusion and thermal evolution. The material models represent metallurgical phenomena during the complete carburizing process. The initial heating of the part induces phases transformation due to austenization. Subsequently, while holding at carburizing temperature, boundary conditions are applied to diffuse carbon into the part. While carbon content increases next to the surface, austenitic metallurgical grain growth is also modelled. A final cooling sets the properties of the carburized part. The model takes into account the phase changes using phase transformation diagrams locally adapted to chemical compositions and grain sizes. Simulation is used to predict the in-use properties of the gear at the end of the carburizing process as well as important results such as assessment of distortion and residual stresses. Thermal stresses, volume variation due to phase changes, and transformation plasticity all contribute to establish the final mechanical properties of the part. During the complete process, the material is modelled with an elasto-viscoplastic behavior and mixing methods are used to consider the relative contribution of each phase.
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Golestanian, Hossein. "Resin Velocity and Pressure Distribution in Resin Transfer Molding of a Composite Cylinder." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72359.
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Resin Transfer Molding (RTM) process in the manufacturing of a composite cylinder is investigated. Resin flow in the woven fiber mat is modeled as flow through porous media to determine resin velocity and pressure distribution along the part. Five-harness carbon and eight-harness fiberglass mats with epoxy resin composites are investigated. Fiber mat permeability for the two fiber types are determined experimentally. These values are then employed in numerical models to simulate the injection cycle of the RTM process. ANSYS finite element software is used to perform the analysis. The results indicate that resin velocity in fiberglass mats is almost six times the velocity in carbon fiber mats. This is due to the higher permeability of fiberglass mats. The sharp drop in the resin velocity into carbon fibers indicates that flow problems will exist in the manufacturing of large carbon/epoxy parts with RTM processes.
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Anagnostakis, Dimitrios, James M. Ritchie, Theodore Lim, Conor Craig, and Jamie Speedie. "The Environmental Impact Assessment of a Company’s Manufacturing System." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-48077.
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The major objective of this study is the estimation of the environmental impacts of a company’s manufacturing system. For this purpose, environmental key performance indicators are selected related to the energy consumption and pollutant gas emissions. To obtain accurate results and achieve an evaluation of the production system, a discrete event simulation tool was equipped. In this way, the production processes of a company were modelled and simulated in order to be assessed with regards to their environmental performance and impacts. The assessment of the investigated manufacturing system was carried out, by comparing it against a hypothetical ideal system of 100% efficiency in order for potential reductions in energy consumption and carbon emissions to be identified. Additionally, a supplementary use of the proposed methodology is presented showing that modelling the production system in advance a company can save energy and associated costs as well as reduce carbon emissions.
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Awad, Hadia, Mustafa Gül, Osama Mohsen, and Simaan AbouRizk. "An integrated simulation-based construction crew allocation and trade-off with energy and carbon footprint." In The 19th International Conference on Modelling and Applied Simulation. CAL-TEK srl, 2019. http://dx.doi.org/10.46354/i3m.2019.mas.016.
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On-site construction in winter consumes a considerable amount of energy and emits a significant volume of greenhouse gases, especially in cold regions. It has been reported that on-site winter heating accounts for 34% of carbon emissions of the framing phase for panelized house construction. In this paper, in order to quantify and analyze carbon emissions from on-site construction, the on-site panelized construction process is simulated in a combined discrete and continuous event simulation model based on which the possibility of reducing activity durations are investigated for the aim of reducing emissions. The integrated simulation methodology is demonstrated using case studies in Edmonton, Canada. Carbon emission which includes propane consumption for winter heating and diesel consumption for on-site mobile equipment and vehicles is calculated. Historical temperature data is analyzed to simulate weather behavior. Results show that on-site heating is the largest contributor to carbon emissions in panelized construction.
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Haavajõe, A., M. Mikola, and M. Pohlak. "Modelling process parameters of the PA12-CF60 carbon fiber laminating tape for low cost laminating devices." In INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0026715.
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IKPEZE, Victoria Kamnetochi, John Olusoji OWOLABI, Idowu Iyabo OLATEJU, and Abdulwahab GIWA. "Modelling and Simulation of Acid Gas Absorption from Natural Gas by Amine Solution Using Aspen HYSYS." In SPE Nigeria Annual International Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/207183-ms.
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Abstract This work has been carried out to model and simulate a typical acid gas absorption process using Aspen HYSYS process simulator. The chemical components involved in the process development were water, methane, ethane, propane, higher alkanes, carbon dioxide, hydrogen sulphide, nitrogen and amines: monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA) and methyldiethanolamine (MDEA). The fluid package selected for the simulation before entering the simulation environment was Acid Gas – Chemical Solvents. In the simulation environment, the model was developed by picking an absorber from the Model Palette, placing it and assigning the input and the output streams involved before inputting the parameters required for model convergence. The carbon dioxide-rich feed gas was made to enter the absorber at the bottom inlet stream while the lean amine stream entered at the top inlet and showered down on the uprising gas thereby trapping the carbon dioxide molecules within the gas. The top product from the absorber was the treated gas while the amine solution and the trapped carbon dioxide left the absorber as the bottom product. Different simulations were run to investigate the performance of the amines under the same operating conditions. It was discovered that, of all the four amine solvents considered in this work for the removal of carbon dioxide by chemical absorption, MEA had the highest efficiency but would require more dehydration because it had the highest water content. DEA was also found to scrub the carbon dioxide down to acceptable levels. However, TEA and MDEA barely scrubbed any carbon dioxide under these conditions, as their carbon dioxide compositions were found to be unacceptable. The analyses of the results obtained from the simulations indicated that Aspen HYSYS can be used to study the process of acid gas absorption successfully.
Reports on the topic "Modelli processo carbonio"
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de Kemp, E. A., H. A. J. Russell, B. Brodaric, D. B. Snyder, M. J. Hillier, M. St-Onge, C. Harrison, et al. Initiating transformative geoscience practice at the Geological Survey of Canada: Canada in 3D. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331097.
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Application of 3D technologies to the wide range of Geosciences knowledge domains is well underway. These have been operationalized in workflows of the hydrocarbon sector for a half-century, and now in mining for over two decades. In Geosciences, algorithms, structured workflows and data integration strategies can support compelling Earth models, however challenges remain to meet the standards of geological plausibility required for most geoscientific studies. There is also missing links in the institutional information infrastructure supporting operational multi-scale 3D data and model development. Canada in 3D (C3D) is a vision and road map for transforming the Geological Survey of Canada's (GSC) work practice by leveraging emerging 3D technologies. Primarily the transformation from 2D geological mapping, to a well-structured 3D modelling practice that is both data-driven and knowledge-driven. It is tempting to imagine that advanced 3D computational methods, coupled with Artificial Intelligence and Big Data tools will automate the bulk of this process. To effectively apply these methods there is a need, however, for data to be in a well-organized, classified, georeferenced (3D) format embedded with key information, such as spatial-temporal relations, and earth process knowledge. Another key challenge for C3D is the relative infancy of 3D geoscience technologies for geological inference and 3D modelling using sparse and heterogeneous regional geoscience information, while preserving the insights and expertise of geoscientists maintaining scientific integrity of digital products. In most geological surveys, there remains considerable educational and operational challenges to achieve this balance of digital automation and expert knowledge. Emerging from the last two decades of research are more efficient workflows, transitioning from cumbersome, explicit (manual) to reproducible implicit semi-automated methods. They are characterized by integrated and iterative, forward and reverse geophysical modelling, coupled with stratigraphic and structural approaches. The full impact of research and development with these 3D tools, geophysical-geological integration and simulation approaches is perhaps unpredictable, but the expectation is that they will produce predictive, instructive models of Canada's geology that will be used to educate, prioritize and influence sustainable policy for stewarding our natural resources. On the horizon are 3D geological modelling methods spanning the gulf between local and frontier or green-fields, as well as deep crustal characterization. These are key components of mineral systems understanding, integrated and coupled hydrological modelling and energy transition applications, e.g. carbon sequestration, in-situ hydrogen mining, and geothermal exploration. Presented are some case study examples at a range of scales from our efforts in C3D.
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Taucher, Jan, and Markus Schartau. Report on parameterizing seasonal response patterns in primary- and net community production to ocean alkalinization. OceanNETs, November 2021. http://dx.doi.org/10.3289/oceannets_d5.2.
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We applied a 1-D plankton ecosystem-biogeochemical model to assess the impacts of ocean alkalinity enhancement (OAE) on seasonal changes in biogeochemistry and plankton dynamics. Depending on deployment scenarios, OAE should theoretically have variable effects on pH and seawater pCO2, which might in turn affect (a) plankton growth conditions and (b) the efficiency of carbon dioxide removal (CDR) via OAE. Thus, a major focus of our work is how different magnitudes and temporal frequencies of OAE might affect seasonal response patterns of net primary productivity (NPP), ecosystem functioning and biogeochemical cycling. With our study we aimed at identifying a parameterization of how magnitude and frequency of OAE affect net growth rates, so that these effects could be employed for Earth System Modell applications. So far we learned that a meaningful response parameterization has to resolve positive and negative anomalies that covary with temporal shifts. As to the intricacy of the response patterns, the derivation of such parameterization is work in progress. However, our study readily provides valuable insights to how OAE can alter plankton dynamics and biogeochemistry. Our modelling study first focuses at a local site where time series data are available (European Station for Time series in the Ocean Canary Islands ESTOC), including measurements of pH, concentrations of total alkalinity, dissolved inorganic carbon (DIC), chlorophyll-a and dissolved inorganic nitrogen (DIN). These observational data were made available by Andres Cianca (personal communication, PLOCAN, Spain), Melchor Gonzalez and Magdalena Santana Casiano (personal communication, Universidad de Las Palmas de Gran Canaria). The choice of this location was underpinned by the fact that the first OAE mesocosm experiment was conducted on the Canary Island Gran Canaria, which will facilitate synthesizing our modelling approach with experimental findings. For our simulations at the ESTOC site in the Subtropical North Atlantic we found distinct, non-linear responses of NPP to different temporal modes of alkalinity deployment. In particular, phytoplankton bloom patterns displayed pronounced temporal phase shifts and changes in their amplitude. Notably, our simulations suggest that OAE can have a slightly stimulating effect on NPP, which is however variable, depending on the magnitude of OAE and the temporal mode of alkalinity addition. Furthermore, we find that increasing alkalinity perturbations can lead to a shift in phytoplankton community composition (towards coccolithophores), which even persists after OAE has stopped. In terms of CDR, we found that a decrease in efficiency with increasing magnitude of alkalinity addition, as well as substantial differences related to the timing of addition. Altogether, our results suggest that annual OAE during the right season (i.e. physical and biological conditions), could be a reasonable compromise in terms of logistical feasibility, efficiency of CDR and side-effects on marine biota. With respect to transferability to global models, the complex, non-linear responses of biological processes to OAE identified in our simulations do not allow for simple parameterizations that can easily adapted. Dedicated future work is required to transfer the observed responses at small spatiotemporal scales to the coarser resolution of global models.
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VanderGheynst, Jean, Michael Raviv, Jim Stapleton, and Dror Minz. Effect of Combined Solarization and in Solum Compost Decomposition on Soil Health. United States Department of Agriculture, October 2013. http://dx.doi.org/10.32747/2013.7594388.bard.
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In soil solarization, moist soil is covered with a transparent plastic film, resulting in passive solar heating which inactivates soil-borne pathogen/weed propagules. Although solarization is an effective alternative to soil fumigation and chemical pesticide application, it is not widely used due to its long duration, which coincides with the growing season of some crops, thereby causing a loss of income. The basis of this project was that solarization of amended soil would be utilized more widely if growers could adopt the practice without losing production. In this research we examined three factors expected to contribute to greater utilization of solarization: 1) investigation of techniques that increase soil temperature, thereby reducing the time required for solarization; 2) development and validation of predictive soil heating models to enable informed decisions regarding soil and solarization management that accommodate the crop production cycle, and 3) elucidation of the contributions of microbial activity and microbial community structure to soil heating during solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays, and samples were subjected to 16S ribosomal RNA gene sequencing to characterize microbial communities. Amendment of soil with 10% (g/g) compost containing 16.9 mg CO2/g dry weight organic carbon resulted in soil temperatures that were 2oC to 4oC higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization. The sequencing data obtained from field samples revealed similar microbial species richness and evenness in both solarized amended and non-amended soil. However, amendment led to enrichment of a community different from that of non-amended soil after solarization. Moreover, community structure varied by soil depth in solarized soil. Coupled with temperature data from soil during solarization, community data highlighted how thermal gradients in soil influence community structure and indicated microorganisms that may contribute to increased soil heating during solarization. Reliable predictive tools are necessary to characterize the solarization process and to minimize the opportunity cost incurred by farmers due to growing season abbreviation, however, current models do not accurately predict temperatures for soils with internal heat generation associated with the microbial breakdown of the soil amendment. To address the need for a more robust model, a first-order source term was developed to model the internal heat source during amended soil solarization. This source term was then incorporated into an existing “soil only” model and validated against data collected from amended soil field trials. The expanded model outperformed both the existing stable-soil model and a constant source term model, predicting daily peak temperatures to within 0.1°C during the critical first week of solarization. Overall the results suggest that amendment of soil with compost prior to solarization may be of value in agricultural soil disinfestations operations, however additional work is needed to determine the effects of soil type and organic matter source on efficacy. Furthermore, models can be developed to predict soil temperature during solarization, however, additional work is needed to couple heat transfer models with pathogen and weed inactivation models to better estimate solarization duration necessary for disinfestation.
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Monasterolo, Irene, María J. Nieto, and Edo Schets. The good, the bad and the hot house world: conceptual underpinnings of the NGFS scenarios and suggestions for improvement. Madrid: Banco de España, February 2023. http://dx.doi.org/10.53479/29533.
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Climate mitigation scenarios are an essential tool for analyzing the macroeconomic and financial implications of climate change (physical risk), and how the transition to a low-carbon economy could unfold (transition risk). The Network for Greening the Financial System (NGFS) has co-developed a set of climate mitigation scenarios for climate financial risk assessment. Despite the important role that these scenarios play in climate stress tests, the understanding of their main characteristics and limitations is still poor. In this paper, we contribute to filling this gap by focusing on the following issues: comparison of the process-based Integrated Assessment Models (IAMs) used by the NGFS with alternative models; the role of Representative Concentration Pathways (RCPs) and Shared Socioeconomic Pathways (SSPs) in shaping the scenario narratives, and their shortcomings; the interpretation and sensitivities of carbon price pathways; and, comparison with other climate mitigation scenarios. We then draw lessons on how to increase the relevance of the NGFS scenarios. These include updating the SSP narratives; considering the potential trade-offs between different types of climate policies; assessing acute physical risks and their compounding; integrating physical risks within transition scenarios; and, taking into account the role of the financial sector and investors’ expectations.
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Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, April 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
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Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.
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Jones, Dale A. Description of the Process Model for the Technoeconomic Evaluation of MEA versus Mixed Amines for Carbon Dioxide Removal from Stack Gas. Office of Scientific and Technical Information (OSTI), November 2013. http://dx.doi.org/10.2172/1113403.
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Lucas, Brian. Impacts of Trade Facilitation on Carbon Emissions. Institute of Development Studies, March 2021. http://dx.doi.org/10.19088/k4d.2021.039.
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There is very little evidence that trade facilitation measures have a significant impact on carbon emissions, except in the case of trucks at land border crossings, where there is good evidence that trade facilitation can lead to significant reductions in emissions. There is good evidence that trade facilitation measures at land border crossings can reduce traffic congestion and waiting times for trucks, but only limited evidence of the impact of these improvements on carbon emissions. Computer models of inspection stations at the USA-Mexico border suggest that improving the efficiency of land border crossings through the driver, vehicle, and cargo pre-registration, automating inspection and administrative processes, and carrying out joint customs inspections could potentially reduce CO2 emissions from trucks by up to 86% in some cases. There appears to be no evidence available about whether trade facilitation efforts at seaports have an impact on carbon emissions; this issue appears to not have been studied by any ports, international agencies, or researchers. Some seaports have produced estimates of their carbon footprints, but none appear to have considered customs inspection or other activities related to trade facilitation as a distinct activity. Very few studies address the impacts of trade facilitation on carbon emissions across global value chains. Two studies that have done so suggest that trade facilitation measures could lead to small increases in CO2 emissions, ranging from less than 0.1% to 2.23%. Studies examining the more general relationship between increasing trade and carbon emissions, without specifically focusing on trade facilitation measures, have found mixed results including positive, negative, and inverse U-shaped relationships in different countries and groups of countries; several of these studies suggest that a country’s level of economic development and quality of political institutions influence the relationship between trade openness and carbon emissions.
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Rueda Ramos, Laura. ESTUDIO PETROGRÁFICO Y GÉNESIS DE LAS CONCRECIONES CARBONÁTICAS (SEPTARIAS) DE LA CAPA DE MARGAS DE ALCORLO (TURONIENSE MEDIO) EN EL SINCLINAL DE TORTUERO (GUADALAJARA, ESPAÑA). Ilustre Colegio Oficial de Geólogos, July 2022. http://dx.doi.org/10.21028/lrr.2022.07.04.
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Las concreciones carbonáticas de tipo septaria objeto del presente estudio se localizan en las proximidades de Tortuero (Guadalajara), en el flanco noroeste (NO) de un sinclinal tumbado en el límite entre el Dominio nororiental del Sistema Central Español y la Cuenca de Madrid. Las concreciones se encuentran en facies mixtas correspondientes a la Capa de Margas de Alcorlo (Turoniense Medio, Cretácico Superior). Esta unidad pertenece a la Mesosecuencia I del Cretácico Superior y corresponde a un máximo regresivo. La metodología empleada para la caracterización mineral y textural ha permitido inferir un posible modelo genético para explicar el origen de estas concreciones carbonáticas. Las concreciones presentan dos formas: una esferoidal y otra discoidal, con diversos tamaños. En su interior se reconocen dos zonas, una interna caracterizada por la presencia de silt (limo) y carbonato (calcita) y una externa de micrita peloidal microbiana, con porosidad secundaria de tipo shrinkage (septarias). Esta porosidad estáparcialmente rellena de un cemento fibroso de calcita. Se deduce que las concreciones se desarrollaron por debajo de la interfase sedimento-agua en un ambiente palustre asociado a la línea de costa. La interrupción de la sedimentación favoreció el crecimiento concrecionar entorno a un núcleo no determinado/visible a partir de aguas continentales freáticas. El origen de las septarias se relaciona con procesos de deshidratación del sedimento por desecación y cementación posterior, característicos de ambientes palustres.
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Bar-Tal, Asher, Paul R. Bloom, Pinchas Fine, C. Edward Clapp, Aviva Hadas, Rodney T. Venterea, Dan Zohar, Dong Chen, and Jean-Alex Molina. Effects of soil properties and organic residues management on C sequestration and N losses. United States Department of Agriculture, August 2008. http://dx.doi.org/10.32747/2008.7587729.bard.
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Objectives - The overall objective of this proposal was to explore the effects of soil properties and management practices on C sequestration in soils and off-site losses of N.The specific objectives were: 1. to investigate and to quantify the effects of soil properties on C transformations that follow OW decomposition, C losses by gaseous emission, and its sequestration by organic and mineral components of the soil; 2. to investigate and to quantify the effects of soil properties on organic N mineralization and transformations in soil, its losses by leaching and gaseous emission; 3. to investigate and to quantify the effects of management practices and plants root activity and decomposition on C and N transformations; and 4. to upgrade the models NCSOIL and NCSWAP to include inorganic C and root exudation dynamics. The last objective has not been fulfilled due to difficulties in experimentally quantification of the effects of soil inorganic component on root exudation dynamics. Objective 4 was modified to explore the ability of NCSOIL to simulate organic matter decomposition and N transformations in non- and calcareous soils. Background - Rates of decomposition of organic plant residues or organic manures in soil determine the amount of carbon (C), which is mineralized and released as CO₂ versus the amount of C that is retained in soil organic matter (SOM). Decomposition rates also greatly influence the amount of nitrogen (N) which becomes available for plant uptake, is leached from the soil or lost as gaseous emission, versus that which is retained in SOM. Microbial decomposition of residues in soil is strongly influenced by soil management as well as soil chemical and physical properties and also by plant roots via the processes of mineral N uptake, respiration, exudation and decay.
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Chefetz, Benny, and Baoshan Xing. Sorption of hydrophobic pesticides to aliphatic components of soil organic matter. United States Department of Agriculture, 2003. http://dx.doi.org/10.32747/2003.7587241.bard.
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Sorption of hydrophobic compounds to aliphatic components of soil organic matter (SOM) is poorly understood even though these aliphatic carbons are a major fraction of SOM. The main source of aliphatic compounds in SOM is above- and below-ground plant cuticular materials (cutin, cutan and suberin). As decomposition proceeds, these aliphatic moieties tend to accumulate in soils. Therefore, if we consider that cuticular material contributes significantly to SOM, we can hypothesize that the cuticular materials play an important role in the sorption processes of hydrophobic compounds (including pesticides) in soils, which has not yet been studied. The overall goal of this research was to illustrate the mechanism and significance of the refractory aliphatic structures of SOM in sorbing hydrophobic compounds (nonionic and weakly polar pesticides). The importance of this study is related to our ability to demonstrate the sorption relationship between key pesticides and an important fraction of SOM. The specific objectives of the project were: (1) To isolate and characterize cuticular fractions from selected plants; (2) To investigate the sorption mechanism of key hydrophobic pesticides and model compounds to cuticular plant materials; (3) To examine the sorption mechanisms at the molecular level using spectroscopic techniques; (4) To investigate the sorption of key hydrophobic pesticides to synthetic polymers; (5) To evaluate the content of cuticular materials in agricultural soils; and (6) To study the effect of incubation of plant cuticular materials in soils on their sorptive capabilities. This project demonstrates the markedly high sorption capacity of various plant cuticular fractions for hydrophobic organic compounds (HOCs) and polar organic pollutants. Both cutin (the main polymer of the cuticle) and cutan biopolymers exhibit high sorption capability even though both sorbents are highly aliphatic in nature. Sorption by plant cuticular matter occurs via hydrophobic interactions and H-bonding interactions with polar sorbates. The cutin biopolymer seems to facilitate reversible and noncompetitive sorption, probably due to its rubbery nature. On the other hand, the epicuticular waxes facilitate enhance desorption in a bi-solute system. These processes are possibly related to phase transition (melting) of the waxes that occur in the presence of high solute loading. Moreover, our data highlight the significance of polarity and accessibility of organic matter in the uptake of nonpolar and polar organic pollutants by regulating the compatibility of sorbate to sorbent. In summary, our data collected in the BARD project suggest that both cutin and cutan play important roles in the sorption of HOCs in soils; however, with decomposition the more condensed structure of the cutin and mainly the cutan biopolymer dominated sorption to the cuticle residues. Since cutin and cutan have been identified as part of SOM and humic substances, it is suggested that retention of HOCs in soils is also controlled by these aliphatic domains and not only by the aromaticrich fractions of SOM.