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Artigos de revistas sobre o assunto "Compost process parameters"
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Adamcová, Dana, František Toman, Magdalena Vaverková e Jana Kotovicová. "THE EFFECT OF BIODEGRADATION/DEGRADATION OF DEGRADABLE PLASTIC MATERIAL ON COMPOST QUALITY". Ecological Chemistry and Engineering S 20, n.º 4 (1 de dezembro de 2013): 783–98. http://dx.doi.org/10.2478/eces-2013-0054.
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Abstract The objective of this study was to find out whether the quality of compost would change during the process of composting carrier bags claimed by manufacturers as compostable or biodegradable in terms of parameters stipulated in the standard ČSN 46 5735 Industrial composts. Eight samples were subjected to the composting process in laboratory conditions. The compost samples were analyzed in the accredited laboratory. All samples met parameters stipulated for Class II. Seven samples of the eight met parameters stipulated in the standard ČSN 46 5735 for Class I. The samples had no influence on compost characteristics: strength, content of water and salt, pH value, content of nutrients or proportion of organic substances; other components of the compost remained unchanged. Optical changes of the compost did not occur either.
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Lasaridi, K. E., e E. I. Stentiford. "BIOLOGICAL PARAMETERS FOR COMPOST STABILITY ASSESSMENT AND PROCESS EVALUATION". Acta Horticulturae, n.º 469 (julho de 1998): 119–28. http://dx.doi.org/10.17660/actahortic.1998.469.11.
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Borisova, Daniela V., Gergana S. Kostadinova, Georgi S. Petkov, Diyana M. Dermendzhieva e Georgi G. Beev. "An Assessment of Two Types of Industrially Produced Municipal Green Waste Compost by Quality Control Indices". Applied Sciences 12, n.º 20 (21 de outubro de 2022): 10668. http://dx.doi.org/10.3390/app122010668.
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Municipal green waste (MGW) has significantly increased with the development of urban green areas, and its utilization by composting is a good alternative to solve the problem. This paper presents the results from the quality assessment of two industrial composts (from the composting facility of a regional nonhazardous waste landfill) based on their physicochemical properties, hygienic safety (microbiological parameters), fertilizing potential (by fertilizing index, FI) and heavy metal polluting potential (by clean index, CI). Compost 1 (C1) was made from MGW (100%) and Compost 2 (C2) was made from MGW (75%) and discarded green peppers (25%). The evaluation of physicochemical parameters was conducted according to Bulgarian Standards (BDS) methods and microbiological analysis using selective, chromogenic detection systems. It was found that the EC, P, K, Mg, Cu, Cr and Ni were lower for C1 (p < 0.05–0.001). On the other hand, Pb concentration was higher compared to C2 (p < 0.001); the concentrations of Cd, Hg and the E. coli were very low for both composts; presence of Salmonella was not detected. The estimated quality indexes (FI and CI) classified C1 as Class B compost (very-good-quality compost with medium fertilizing potential) and C2 as Class A compost (best-quality compost with high soil fertility potential and low heavy metal content). The C1 and C2 composts meet the requirements of EU and Bulgarian legislation and can be used as soil fertilizers.
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Leone, Alessandro, Roberto Romaniello, Antonia Tamborrino, Luciano Beneduce, Anna Gagliardi, Marcella Giuliani e Giuseppe Gatta. "Composting of Olive Mill Pomace, Agro-Industrial Sewage Sludge and Other Residues: Process Monitoring and Agronomic Use of the Resulting Composts". Foods 10, n.º 9 (10 de setembro de 2021): 2143. http://dx.doi.org/10.3390/foods10092143.
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The viability of co-composting of olive mill pomace added to sewage sludge with other organic residues was evaluated and the agronomic use of the final composts was investigated. Two composting piles at different carbon-nitrogen ratios were performed, in which olive mill pomace (OMP), sewage sludge from vegetable processing (SS), fresh residues from artichoke processing residues (AR), and wheat straw (WS) were used. The two composting piles were placed inside a specially built greenhouse and a turning machine pulled by a tractor was used for turning and shredding the organic matrix (every 6 days) during the process. The humidity and temperature of organic matrices have been monitored and controlled during the entire composting process, which lasted 90 days. The process was also monitored to evaluate the microbiological safety of the final compost. The humidity of both piles was always kept just above 50% until the end of the thermophilic phase and the maximum temperature was about 50 °C during the thermophilic phase. The carbon-nitrogen ratio decreased from 21.4 and 28.2, respectively (initial value at day 1 in Pile A and B), to values ranging from 12.9 to 15.1, both composts that originated from the two different piles were microbiologically safe. During a two-year period, the effects of different types of compost on the main qualitative parameters of processing tomato and durum wheat was evaluated. Five fertilization treatments were evaluated for tomato and durum wheat crops: unfertilized control (TR1); compost A (TR2); compost B (TR3); ½ mineral and ½ compost A (TR4); and mineral fertilizer commonly used for the two crops (TR5). Concerning the processing tomato yield, TR5 and TR4 showed the best results (2.73 and 2.51 kg, respectively). The same trend was observed considering the marketable yield per plant. The only difference was related to the treatments that included the compost (2.32, 1.77, and 1.73 kg/plant for TR4, TR3, and TR2, respectively). As regards the qualitative parameters of tomato, the highest average weight of the fruits was found in the TR5, TR4, and TR3 treatments (respectively, 73.67 g, 70.34 g, and 68.10 g). For durum wheat, only the protein component was differentiated between treatments. Furthermore, wheat grain yield parameters generally increased by combined application of mineral fertilizer and compost.
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Malovanyy, Myroslav, e Uliana Storoshchuk. "OBTAINING AND USING SUBSTRATES WITH SEWAGE SLUDGE". Environmental Problems 7, n.º 3 (2022): 154–62. http://dx.doi.org/10.23939/ep2022.03.154.
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The article is devoted to the study of the prospects of using compost with sewage sludge in the raw material for the recultivation of disturbed lands. A special installation was used for bio-composting, which allowed controlling of the process parameters. The results of bio-indication of composts obtained under different conditions of compositions of the raw material mixture are given. Based on the analysis of the results of bio-indication, the optimal composition of the raw material mixture using "fresh" and "old" sewage sludge is established. An analysis of the parameters of the bio-indication process was carried out for this compost of optimal composition, which makes it possible to develop recommendations for the implementation of the process in industrial conditions.
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Lin, Chitsan, Chih-Chiang Wei e Chia-Cheng Tsai. "Prediction of Influential Operational Compost Parameters for Monitoring Composting Process". Environmental Engineering Science 33, n.º 7 (julho de 2016): 494–506. http://dx.doi.org/10.1089/ees.2015.0259.
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Palma, Alberto, Victor M. Doña-Grimaldi, Mercedes Ruiz-Montoya, Inmaculada Giráldez, Juan Carlos García, Javier Mauricio Loaiza, Francisco López e Manuel J. Díaz. "MSW Compost Valorization by Pyrolysis: Influence of Composting Process Parameters". ACS Omega 5, n.º 33 (12 de agosto de 2020): 20810–16. http://dx.doi.org/10.1021/acsomega.0c01866.
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Vannucchi, Francesca, Eleonora Peruzzi, Serena Doni, Davide Manzi, Lapo Azzini, Shamina Imran Pathan, Giacomo Pietramellara et al. "Biological Assessment of Green Waste and Dredged Sediment Co-Composting for Nursery Plant Cultivation". Applied Sciences 14, n.º 13 (1 de julho de 2024): 5767. http://dx.doi.org/10.3390/app14135767.
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Co-composting efficiently reclaims dredged sediments (S) and green waste (GW), creating stable products for agricultural applications. However, the use of S-GW co-composts can be limited by legislative thresholds, especially for co-composts with a high S percentage. The evaluation of S-GW co-compost stability by biological assessment can allow for a better understanding of S and GW recycling, as well as the S-GW co-compost application. For this purpose, the microbial biomass, composition, respiration, and eco-enzyme stoichiometry (EST) were assessed, coupled with chemical analysis, in the co-composting of S and GW in different ratios. The Photinia x fraseri and Viburnum tinus L. growth was monitored in a plant trial, comparing the studied co-composts with a control substrate. The EST approach was applied as an indicator of the co-composting stability during the process and after the plant cultivation. The chemical and biological parameters confirmed the suitability of co-composting in the GW and S recovery and the EST approach highlighted a better stability for the 3S:1GW co-compost at the end of the process and after plant cultivation. Viburnum tinus showed a similar growth to the control, while Photinia x fraseri resulted in being more sensitive to the co-compost. The biological assessments were good indicators of the S-GW compost stability for their application in crop cultivation.
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Villalba, Luisa, Jorge Paolini e Carlos Rocha. "Some biological parameters in the evaluation of the stability and maturity of two compost". Revista de la Facultad de Agronomía, Universidad del Zulia 38, n.º 1 (17 de dezembro de 2020): 06–30. http://dx.doi.org/10.47280/revfacagron(luz).v38.n1.01.
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Composting represents an alternative for the use of organic waste by transforming it into an organic amendment that improves the structure and fertility of soils. As it is a microbiological process, the objective was to analyze some biological parameters in the evaluation of the stability and maturity of two compost. Two compost was made with waste generated at the Simón Bolívar University one obtained from organic waste generated in the dining room and the other from plant remains from the pruning of the gardens. The parameters evaluated were temperature and microbial count, expressed as colony-forming units per gram of compost for yeast, and for aerobic and anaerobic bacteria (in turn classifying the bacteria by the Gram staining method), as well as the germination index determined by the phytotoxicity test. The results obtained allowed us to conclude that: the temperature of the compost pile is a good indicator of the evolution of the composting process, as it is closely associated with biological activity indicating the stages of the process, in the compost analyzed, the counting of microorganisms allowed to evaluate them as stable, the bacterial classification by Gram staining, represented a good indicator of the successions that occur in the composting process and was useful to help the classification of the bacteria present; the phytotoxicity test corroborated the degree of maturity and stability of the studied compost.
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McKinley, James W., Rebecca E. Parzen e Álvaro Mercado Guzmán. "Impact of climate and bulking materials on characteristics of compost from ecological toilets". Journal of Water, Sanitation and Hygiene for Development 2, n.º 2 (1 de junho de 2012): 79–86. http://dx.doi.org/10.2166/washdev.2012.059.
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Urine-diversion dehydration toilets (UDDT) are common throughout the developing world, and the toilet product is widely used as compost. There is no comprehensive research to date that characterizes the compost to determine its quality, extent of pathogen inactivation, and the effects of climate and bulking materials on the compost. Compost was collected from 45 UDDT in Bolivia and analyzed for physical, chemical, and biological parameters. Eighty percent and 56% of samples did not meet acceptable compost guidelines for moisture content and pH, respectively, indicating desiccation was the dominant process in UDDT. Bulking materials significantly impacted compost characteristics in terms of pH, carbon, carbon-to-nitrogen ratio, and carbon stability (P < 0.05). Composts with ash exhibited, on average, low carbon concentrations (4.9%) and high pH values (9.7), which can be harmful to plants and composting microorganisms. Composts with sawdust exhibited, on average, high carbon concentrations (40.0%) and carbon-to-nitrogen ratios (31.0). Climate had no significant impact on chemical characteristics, however composts from humid regions had significantly higher moisture contents (34.4%) than those from arid climates (24.8%) (P < 0.05). Viable Ascaris lumbricoides ova were identified in 31% of samples, including samples with high pH, low moisture contents, and long storage times.
Teses / dissertações sobre o assunto "Compost process parameters"
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Lotfi, Amirhossein. "Study on the Machinability of Natural Fiber Reinforced Composite Materials". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/396146.
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Interest in natural fiber reinforced composites (NFRCs) is increasing rapidly thanks to their numerous advantages such as low cost, biodegradability, eco-friendly nature, relatively good mechanical properties, and a growing emphasis on the environmental and sustainability aspects of engineering materials. However, large scale use of NFRCs is still considered as challenging due to the difficulties in manufacturing, limited knowledge of its machinability and appropriate parameter settings, and being prone to machining-induced defects. These materials are known as hard-to-machine materials due to their heterogeneous structure, mechanical anisotropy and tendency to damage while exposed to mechanical stresses. High rejection rate of composite parts at the assembly stage because of poor quality hole due to several vital drilling induced damages such as matrix cracking, fiber pull-out, delamination, fiber and matrix separation and thermal degradation is a serious concern for manufacturing industries. Among all these defects, delamination was found to be the most vital life-limiting factor which affects the mechanical strength and structural integrity of the component significantly in terms of dimensional tolerances and load carrying capability. Therefore, the main objective of this research is investigating the influence of drilling process parameters on the machinability of flax/poly(lactic acid) bio-composites along with characterization, modelling, and condition monitoring of drilling operation through extensive experimental and analytical investigations.
The effect of key drilling parameters and tool geometry such as cutting speed, feed rate, drill diameter, drill material and point angle at different levels were studied experimentally to analyse the relations between resultant quality of the produced holes, cutting forces and size of delamination. Damages and defects associated with the drilling process such as delamination, fiber breakage, fiber pull-out, and matrix cracking were studied through qualitative measurements, optical microscopy and scanning electron microscopy examination. Experimental results revealed that the choice of drill bit in terms of diameter, material and point angle has a considerable effect on the machinability and hole performance. Drilling with HSS drills resulted in nearly 60% lower thrust force and better hole quality compared to that with carbide drills. In addition, the analysis of variance (ANOVA) was applied to identify the significance of each individual cutting parameter.
Analytical model was developed to predict the critical thrust force related to the onset of delamination propagation during drilling FF/PLA laminates. The delamination zone was modelled as an elliptical plate, with clamped edge and the analytical model developed based on theory of virtual work, LEFM methodology and theory of plate bending. An experimental investigation was carried out, in addition to the analytical model, through a punching test on different configurations of blind hole to characterize the critical thrust force at the onset of delamination. The developed model has been verified by experimental data and compared with the results of existing models and the presented model considering the effect chisel edge and cutting edges. Based on the results, the predicted values by the proposed model present better correlation with the experimental values than those predicted by other models.
A relationship exists between cutting variables (thrust and cutting forces), tool wear and the final quality of the drilled hole. Accordingly, the quality of drilled holes can be improved by in-process monitoring in order to record the whole process status through measuring the thrust force and other indicators. An experimental investigation on online monitoring and non-destructive evaluation of drilling operation using vibration, acoustic emission and thrust force signals was conducted and the correlation between the cutting parameters, delamination, cutting thrust force and the pattern of the signals was detected. The response of material through acceleration, force and AE signals were analysed using different signal analysis tools and statistical parameters to derive the features of signals that can express the key characteristics of machining condition. It is observed that the AE rms values are affected by variation in the cutting parameters and it follows a similar trend as observed in the case of drilling thrust force by varying cutting conditions. The variation of vibration and acoustic emission signals were in correlation with delamination factor and damage severity. Four major damage mechanisms have been identified generally as the main sources of AE energy wave in drilling of FF/PLA composites namely fiber breakage, delamination, matrix cracking and friction. A process for detection and discrimination of various damage mechanisms can be correlated to the frequency of damages. Furthermore, among several statistical parameters applied on the effective segment of the time signals, Kurtosis was found the most competent statistical parameter for condition monitoring of the drilling process to to differentiate between poor and good quality of the drilled holes and enhance the quality of composite component. The findings from this research concluded that damage severity can be assessed through AE parameter analysis and it has a considerable potential for the application of in-process monitoring.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Tufail, Muhammad. "Effects of textile and process parameters on the properties of hybrid thermoplastic composites". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287237.
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Demaree, Robert John. "The effects of process parameters on the properties of resin transfer molded composites". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11182008-063452/.
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Taetragool, Unchalisa. "Optimal Parameters for Doubly Curved Sandwich Shells, Composite Laminates, and Atmospheric Plasma Spray Process". Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/81978.
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Optimization is a decision making process to solve problems in a number of fields including engineering mechanics. Bio-inspired optimization algorithms, including genetic algorithm (GA), have been studied for many years. There is a large literature on applying the GA to mechanics problems. However, disadvantages of the GA include the high computational cost and the inability to get the global optimal solution that can be found by using a honeybee-inspired optimization algorithm, called the New Nest-Site Selection (NeSS). We use the NeSS to find optimal parameters for three mechanics problems by following the three processes: screening, identifying relationships, and optimization. The screening process identifies significant parameters from a set of input parameters of interest. Then, relationships between the significant input parameters and responses are established. Finally, the optimization process searches for an optimal solution to achieve objectives of a problem.
For the first two problems, we use the NeSS algorithm in conjunction with a third order shear and normal deformable plate theory (TSNDT), the finite element method (FEM), a one-step stress recovery scheme (SRS) and the Tsai-Wu failure criterion to find the stacking sequence of composite laminates and the topology and materials for doubly curved sandwich shells to maximize the first failure load. It is followed by the progressive failure analysis to determine the ultimate failure load. For the sandwich shell, we use the maximum transverse shear stress criterion for delineating failure of the core, and also study simultaneously maximizing the first failure load and minimizing the mass subject to certain constraints. For composite laminates, it is found that the first failure load for an optimally designed stacking sequence exceeds that for the typical [0°/90°]₅ laminate by about 36%. Moreover, the design for the optimal first failure load need not have the maximum ultimate load. For clamped laminates and sandwich shells, the ultimate load is about 50% higher than the first failure load. However, for simply supported edges the ultimate load is generally only about 10% higher than the first failure load.
For the atmospheric spray process, we employ the NeSS algorithm to find optimal values of four process input parameters, namely the argon flow rate, the hydrogen flow rate, the powder feed rate and the current, that result in the desired mean particle temperature and the mean particle velocity when they reach the substrate. These optimal values give the desired mean particle temperature and the mean particle velocity within 5% of their target values.Ph. D.
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Infante, Eleonora. "Influenza dei parametri di processo delle caratteristiche meccaniche di materiali compositi". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9505/.
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Lo scopo di questa tesi è valutare la resistenza a compressione e il valore del modulo elastico di tre laminati ottenuti con lo stesso materiale composito, CFRP, distinti in fase di laminazione dall’utilizzo di tre diverse tipologie di distaccante (peel-ply, film distaccante e controstampo). In questo modo è stato possibile valutare come quest’ultimi abbiano influito, in modo diverso per ogni laminato, sull’omogeneità dello spessore, sul peso, sulla fuoriuscita di resina e sulla percentuale volumetrica delle fibre. Tali fattori a loro volta hanno caratterizzato i valori di resistenza a compressione e modulo elastico.
Nei capitoli successivi è descritto un metodo di analisi a compressione dei materiali compositi, a matrice epossidica rinforzata con fibre di carbonio (CFRP), denominato Combined Loading Compression (CLC) Test Method, basato sull’applicazione, combinata, del carico sul campione, a taglio e all’estremità.
La realizzazione dei provini è stata effettuata presso i laboratori dell’università: sono stati realizzati 3 laminati, per ognuno dei quali si è scelto di utilizzare su ogni pezzo una diversa tipologia di distaccante: controstampo, film distaccante e peel-ply, allo scopo di valutare quanta resina uscirà dal manufatto una volta in autoclave e quanta variazione di spessore avremo. Da ognuno di questi laminati sono stati ricavati 5 provini.
La campagna sperimentale è stata condotta presso il Laboratorio Tecnologie dei Materiali Faenza (TEMAF).
L’elaborazione dei dati è stata effettuata mediante l’utilizzo del software Office Excel, in cui sono stati calcolati i parametri fondamentali, suggeriti dalla normativa ASTM D6641/D6641M, per la caratterizzazione meccanica a compressione dei materiali CFRP.
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Gajjela, Pavan. "Effect of Electrochemical Process Parameters on the Properties of Polyaniline/polypyrrole Coatings on Stainless Steel". Cincinnati, Ohio : University of Cincinnati, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1097451143.
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Fogagnolo, João Batista 1964. "Contribuição a analise dos efeitos de parametros de processo na qualidade de compositos obtidos por compofundição". [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263608.
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Orientador: Maria Helena RobertDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-07-21T16:49:30Z (GMT). No. of bitstreams: 1 Fogagnolo_JoaoBatista_M.pdf: 26146383 bytes, checksum: 6d12494171db86dbfa479cd5ece66b84 (MD5) Previous issue date: 1996
Resumo: Neste trabalho são investigados os efeitos de parâmetros de processo na eficiência de incorporação do reforço carboneto de silício na forma de partículas, na liga AA7075 e na sua distribuição na estrutura do compósito produzido. O tipo de processamento utilizado foi por compofundição, ou seja, a adição do reforço na matriz metálica em estado semi-sólido reofundido. Para isto, foi projetado e construído um equipamento, não disponível no mercado, para a obtenção de estruturas pastosas reofundidas e a adição de partículas de reforço a esta, obtendo-se assim, os materiais compósitos desejados. Os lingotes reofundidos e compofundidos então obtidos atestam a eficiência do equipamento projetado e construído. Os efeitos de parâmetros de processo observados foram: a redução da temperatura de processamento aumenta a esfericidade dos glóbulos obtidos e diminui significativamente a quantidade de fase líquida na pasta, aumentando a sua viscosidade, resultando em melhor incorporação do reforço, com menor porosidade causada devido ao processo de adição, porém, não leva à desejada distribuição da fase reforçante pelo lingote. Maiores temperaturas levam à melhor distribuição das fases sólida/líquida pelo volume do lingote, conseqüentemente melhor distribuição da fase reforçante, porém, com pior incorporação desta, devido à maior porosidade associada ao processo de adição. O aumento do tempo de processamento leva à separação das trações líquidas e sólidas na pasta, o que produz acentuadas heterogeneidades macro e microestrutural. O aumento da velocidade de agitação leva à melhor distribuição das trações sólida e líquida na pasta, melhorando a distribuição da fase reforçante e possibilitando maior quantidade de reforço adicionada à pasta sem problemas. Maiores quantidades de reforço adicionadas auxiliam a obtenção de estrutura globular devido à maior tração sólida total da pasta, porém, introduzem maior porosidade no produto compofundido devido ao processo de adição do reforço
Abstract: The effects of process parameters in the efficiency of incorporation and distribution of silicon carbide particulate in AA7075 alIoy are investigated. The composites were produced by compocasting. It was necessary to design and build an equipament based on mechanical stirring of the liquid alIoyduring its solidification, to produce rheocast slurries and composites. The observed effects of process parameters in the compocast ingots were: reducing temperature leads to improvement in the espherical morphology of primary phase in the slurry; reduces the liquid the liquid content; increases the viscosity, resulting in better incprporation of the reinforcement, less porosity and not uniform final distribution of silicon carbide in the matrix. On the oposite, processing at higher temperature leads to higher liquid content and better distribution of silicon carbide particles. However, more gases can be associated damaging incorporation. Increasing stirring time leads to separation of liquidlsolid phases in the slurry, promoting heterogeneities in the macro and microstructures. Increasing stirring speed promotes better distribution of liquid/solid phases and silicon carbide particles in the ingot. Higher speeds also allow higher content of reinforcement to be added. Higher reinforcement content helps to produce globular solid phase in the matrix
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Isbilir, Ozden. "Optimisation of the geometry of the drill bit and process parameters for cutting hybrid composite/metal structures in new aircrafts". Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2890/.
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Torres, Juan David. "Effect of geometrical and process parameters on the quality of open moulded composite parts with sharp corners : a decision-based approach". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53437.
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The use of autoclaves and ovens in modern composite manufacturing processes has shown a potential to greatly control the geometry and structural properties of composite materials. The use of such manufacturing tools has been supported by numerical tools and optimization/statistical methods, in order to further improve the quality of composite products. However, the costs associated with these advanced manufacturing techniques are not always acceptable for all Fiber Reinforced Composite (FRC) manufacturers. In particular, for large products with low production rates (e.g., marine and automotive industries), open moulding are preferred as they typically offer the best compromise between the quality of the part and manufacturing production cost. The quality of open-moulded parts, however, is highly dependent on the skill of the operator, hence resulting in possible variations in part properties, particularly for geometrically complex parts. This variation often causes out-of-specification products, resulting in costly trial and error approaches to minimize the product defects. The purpose of this thesis was to study the FRC process conditions that have a statistically significant effect on the generation of defects in open-moulded parts with sharp corner (i.e., small radius) features. Samples with different geometrical, material and process parameters were manufactured. Defects such as void content, corner fiber bridging, fabric formability, fiber misalignment and bending resistance of the material were evaluated through different characterization techniques. The statistical analysis of the data has provided new means to determine the contribution of each parameter to the final quality of the composite part. The results suggest that the part radius and part thickness both have significant effects on the bending resistance of the FRC specimens. Also, it was observed that reinforcement orientation has a significant effect on the formability and surface defects around the part corners. Finally, a novel Multiple Criteria Decision Making (MCDM) approach has been developed using “signal to noise” ratios with subjective and objective weighting, in order to identify the optimum design parameters for both aesthetic and structural properties of the open moulded FRC parts with sharp corners.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Pinza, Elisabetta. "Studio e caratterizzazione dell'influenza dei parametri di processo sulla tenuta di un inserto filettato installato su materiale composito". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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Il seguente elaborato tratta delle problematiche legate ad installazione e tenuta di collegamenti meccanici come inserti filettati applicati su materiali compositi, nello specifico componenti realizzati in fibra di carbonio.
Lo scopo di tale studio è di carattere principalmente preventivo, nell'ottica di individuare quali parametri di processo siano più o meno incisivi.
Capítulos de livros sobre o assunto "Compost process parameters"
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Kleineberg, Markus, Nico Liebers e Michael Kühn. "Interactive Manufacturing Process Parameter Control". In Adaptive, tolerant and efficient composite structures, 363–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29190-6_29.
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Ramesh, M., e K. Niranjana. "Effect of Process Parameters on Fused Filament Fabrication Printed Composite Materials". In High-Performance Composite Structures, 155–78. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7377-1_7.
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Fisker, J. L., F. Rembges, V. Barnard e M. C. Wiescher. "The Rp-Process on Compact Binaries: Importance of Exact Parameters". In The Influence of Binaries on Stellar Population Studies, 569–71. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9723-4_43.
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Triminì, Valentina, Sara Varetti, Gianluca Percoco, Stefano Corvaglia, Nicola Gallo e Ignazio Scavo. "Influence of Process Parameters of 3D Printed PEEK on Crystallinity and Mechanical Performances". In Dynamic Response and Failure of Composite Materials, 173–79. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28547-9_21.
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Tamilarasan, A., T. Rajmohan, D. Rajamani e K. Palanikumar. "Optimization of Process Parameters in AWJ Cutting of Pineapple Fiber Reinforced Polymer Composites: Hybrid SCCSA Algorithm". In Bio-Fiber Reinforced Composite Materials, 125–40. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-8899-7_7.
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Nayak, Soumyaranjan, Abhishek Kumar Singh, Hina Gokhale, M. J. N. V. Prasad e K. Narasimhan. "A Numerical Study to Analyze the Effect of Process Parameters on Ring Rolling of Ti-6Al-4V Alloy by Response Surface Methodology". In Lecture Notes in Mechanical Engineering, 315–35. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-58006-2_25.
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AbstractHot ring rolling is a production method to manufacture seamless rings. It is a complex incremental metal-forming process where reduction of cross-section leads to increase in diameter of the ring via circumferential extrusion. High degree of non-linearity and asymmetry is associated with the process. The process results in non-uniform distribution of temperature and plastic strain in the ring cross-section, and this in turn significantly affects the deformation behavior, microstructure, and mechanical properties. Form defect like fishtail defect is also a major concern and incurs loss in terms of labor and machining cost. In this study, rolling of Ti-6Al-4V rings is studied with the help of three-dimensional coupled thermo-mechanical finite element model established using ABAQUS/Explicit environment-based dynamic explicit code. The major parameters taken into consideration for the study are main roll speed (rpm), main roll feed (mm/s), and coefficient of friction. Each parameter was studied at two levels. Twenty simulations with different combinations of major parameters were developed via Central Composite Design (CCD). Coefficient of Variation (CoV) was used as a heterogeneity index to ascertain heterogeneity in equivalent plastic strain (PEEQ) and temperature distribution in the ring. Fishtail defect was quantified using fishtail coefficient as an index. Analysis of variance (ANOVA) was used to ascertain the impact of significant factors and interactions between different parameters affecting the ring rolling process. ANOVA technique requires unrestricted range of (−∞, ∞) for analysis. Hence, logit transformation is used to transform fishtail coefficient present in the range 0–1 to an unrestricted real number range (−∞, ∞). Main roll feed rate was found to be the most significant factor affecting CoV (PEEQ), CoV (temperature) and logit transformation of fishtail coefficient and has an inverse correlation and quadratic relationship with all the responses. Other sources of variation like main roll speed (rpm) and coefficient of friction (CoF) have minimal impact. Increase in feed rate was found to reduce CoV (PEEQ), CoV (temperature), and logit transformation of fishtail coefficient.
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Ezeddini, Sonia, Mohamed Boujelbene, Emin Bayraktar e Sahbi Ben Salem. "Recycled Ti-17 Based Composite Design; Optimization Process Parameters in Wire Cut Electrical Discharge Machining (WEDM)". In Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 5, 109–25. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95510-0_14.
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Deng, Liwen, Jianting Pan, Haolin Ye, Jinming Zeng, Hao Lu e Hong Pan. "Study on Ground Deformation Law of Small Spacing Shield Tunneling in Sand and Rock Composite Stratum". In Lecture Notes in Civil Engineering, 239–52. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2532-2_20.
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AbstractThe construction of shield tunnel often occurs in composite stratum, so it is of great significance to study the law of surface deformation under the working condition of composite stratum in order to ensure the safety of shield construction. Based on the actual tunnel engineering, the law of ground surface soil deformation caused by shield construction in the composite stratum of upper sand and lower rock is studied by using the method of field measurement. The results show that: The width coefficient of the surface settlement trough basically remains stable with the shield construction, and the stratum loss rate changes exponentially with the shield construction; Affected by the disturbance of the previous shield construction, the surface settlement trough caused by the subsequent shield construction is no longer on the top of the tunnel axis, and will move with the construction process, which is greatly affected by the shield attitude parameters; Taking into account the conditions of the center movement of the settlement trough of the subsequent tunnel, the total surface settlement caused by the successive shield constructions adopts the modified Mark-bolt formula to make the fitting parameters of the settlement trough more suitable for reality.
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Li, Yongxiang, Xiatong Kang, Qi Gao e Yongjie Jia. "Rheological Properties of Composite Modified Asphalt with Direct Coal Liquefaction Residues". In Lecture Notes in Civil Engineering, 59–74. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1748-8_5.
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AbstractIn order to solve the problem of high-value utilization of coal-to-oil residual direct coal liquefaction residual asphalt, it is compounded with SBS and aromatic oil to modify the matrix asphalt, and 9 compounding schemes are designed using orthogonal experimental methods. Dynamic frequency sweep tests using DSR and a simplified Carreau equation model fitted to the complex viscosity to obtain its zero shear viscosity; the creep recovery rate, irrecoverable creep flexibility and irrecoverable creep flexibility difference of each modified asphalt were determined by MSCR at different temperatures and stress levels, and the high temperature rheological properties of 9 composite modified asphalts were evaluated by grey correlation analysis of zero shear viscosity and high temperature rheological parameters. Bending beam rheological experiments were carried out on the aged composite modified asphalt to analyse its low temperature rheological properties based on the viscoelastic parameters and linear fitting of the Burgers model. The results show that: The high temperature deformation resistance of DCLR composite modified asphalt are better than the matrix asphalt, the most influential modifier is SBS, and the higher the dose, the stronger the high temperature deformation resistance. The unrecoverable creep flexibility Jnr3.2 at 70 °C can better respond to the high temperature performance of asphalt, the ratio of 9% DCLR + 4% SBS + 2% aromatic oil DCLR composite modified asphalt with the best high temperature performance. Burgers model can better reflect the creep process of asphalt, DCLR composite modified asphalt has some defects in low temperature performance, the higher the dose of DCLR, the poorer the low temperature performance of the composite modified asphalt. The low temperature sensitivity of DCLR composite modified asphalt has been reduced, low temperature crack resistance has been slightly enhanced.
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Wan, Qian, Li Wang e Guowei Ma. "Adaptable Tool-Path Planning Method for 3D Concrete Printing Based on the Mapping Method". In Proceedings of the 2020 DigitalFUTURES, 255–64. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4400-6_24.
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Abstract3D concrete printing (3DCP) has been successfully and widely applied in the fields of civil structure, infrastructure, architectural decoration etc.,due to its unique advantages of automation and flexibility, and has shown great potential for development. One of the key steps in the execution of 3DCP is the tool-path planning process. However, 3DCP typically utilize the flowable composite materials which changes with time, and it is easy to induce interface joints or filling defects due to uneven path distribution when constructing the irregular-shaped construction. To solve the problem of printing path planning in 3DCP, this paper proposes tool-path planning based on mapping method, which integrates the rheology and necessary continuity of concrete materials into the printing process parameters, improves the mutual adaptability of printing process and material characteristics, improves the continuity of printing, the compactness of filling, and then ensures the stability and durability of printing structure.
Trabalhos de conferências sobre o assunto "Compost process parameters"
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Soreanu, Gabriela, Igor Cretescu, Elena Niculina Dragoi, Doina Lutic e Florin Leon. "TOWARDS LOW-CARBON EMISSION BIOTRICKLING FILTRATION OF VOLATILE ORGANIC COMPOUNDS FROM AIR: AN ARTIFICIAL NEURAL NETWORK APPROACH". In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/4.1/s19.55.
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In this study, a classical biotrickling filter (based on compost microorganisms) and an upgraded biotrickling filter (based on a mixture of compost microorganisms and microalgae Arthrospira platensis PCC 8005) are evaluated in terms of carbon dioxide production, during their use for volatile organic compounds (VOCs) removal from air. The experiments were performed using acetic acid vapors as model VOC and the biotrickling filter (BTF) performance was observed at different VOC concentrations, gas flowrates and pH values. Although the removal of acetic acid vapors was maximum for the both biosystems, the carbon dioxide production was different. The influence of the microorganisms� types and of the operating parameters on the carbon dioxide production are correlated via artificial neural network algorithms, depicting the most favorable conditions towards a low-carbon emission biotrickling filtration process for VOCs removal from air.
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Cisler, Martin, Frantisek Horejs, Michal Strnad e Libor Matyas. "Influence of organic fertilizers on soil erosion parameters in maize crop". In 23rd International Scientific Conference Engineering for Rural Development. Latvia University of Life Sciences and Technologies, Faculty of Engineering and Information Technologies, 2024. http://dx.doi.org/10.22616/erdev.2024.23.tf165.
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Every year, large amounts of agricultural land are threatened by water erosion. Fields with sloping land are particularly at risk. The impact of water erosion on soil and fine soil particles is very serious. Water erosion is a natural process and cannot be stopped. It can only be reduced or slowed down. To reduce the impact of water erosion, erosion control measures are used to protect the soil surface and fine soil particles. The most risk crops from the view of water erosion are wide-row crops. The aim of this research was to assess the effect of organic fertilizers on soil erosion parameters in maize crop. To achieve the results, a field experiment focusing on three organic fertilizers (manure, digestate, compost), was established on a sloping plot with an average slope of 5.29°. Each fertilizer was represented in two variants at different rates. Two variants were added as a control. One with maize cover without fertilizer application and the second without vegetation. Surface runoff and erosive wash were measured using the micro-parcel runoff method. Based on the results from the measurements, a positive effect of organic fertilizers on water erosion mitigation can be demonstrated, primarily reducing erosive wash and surface runoff. Both are associated with improved soil infiltration. It is therefore possible to consider the use of infiltration strips with extreme doses of organic fertiliser on erosion-prone areas of land. Furthermore, there was no confirmation of the expected reduction in soil water infiltration for the option where digestate was applied.
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Jezek, Damir, Branko Tripalo e Mladen Brncic. "INFLUENCE OF DIFFERENT PROCESS PARAMETERS ON VEGETABLE DRYING IN GAS FLUIDIZED BEDS". In Compact Heat Exchangers and Enhancement Technology for the Process Industries - 2003. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/978-1-56700-195-2.330.
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Ou, Xinyan, Maen Alkhader e Qing Chang. "Experimental Analysis of Process Parameters in Composite Manufacturing". In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8518.
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With the growing world demand on composite products, composite manufacturers are increasingly moving towards adopting automated composite manufacturing. However, current automated machines are not optimized and have throughput limitations. Most of them only target specific composite processes. Because the shortage of understanding on the processing factors and knowledge on precise process control, the products get high probability to come with defect. This paper provides an experimental methodology to explore the relationship between the structural properties of composite parts and processing factors. The paper also provides composite manufacturers a guide for processing condition optimization, productivity improvement and cost reduction. The raw material involved in this paper is an aerospace grade carbon fiber prepreg and was used to fabricate composite samples in a hot press machine system in the experiment. To investigate the effects of processing factors, specimens were fabricated using a series of combinations of different factor values. Three point bending flexural test was performed to evaluate the quality of each sample. Collected data are analyzed by statistical methods and fitted to a multiple linear regression model, which provides insights for composite manufacturing.
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Kondratiev, A. V., V. Ye Gaidachuk e T. P. Nabokina. "Analysis of flattening process parameters for the carbon composite material". In SCIENCE, ENGINEERING AND TECHNOLOGY: GLOBAL TRENDS, PROBLEMS AND SOLUTIONS. Baltija Publishing, 2020. http://dx.doi.org/10.30525/978-9934-588-79-2-1.27.
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Latha, B., e V. S. Senthilkumar. "Simulation Optimization of Process Parameters in Composite Drilling Process Using Multi-objective Evolutionary Algorithm". In 2009 International Conference on Advances in Recent Technologies in Communication and Computing. IEEE, 2009. http://dx.doi.org/10.1109/artcom.2009.100.
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Takeuchi, K., e M. Hane. "A Highly Efficient Statistical Compact Model Parameter Extraction Scheme". In 2005 International Conference On Simulation of Semiconductor Processes and Devices. IEEE, 2005. http://dx.doi.org/10.1109/sispad.2005.201491.
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Pali, Harveer Singh, Naveen Kumar e Kausambi Singh. "Optimisation of Process Parameters of EDM on Al6082/SiC Metal Matrix Composite". In SAE 2016 World Congress and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2016. http://dx.doi.org/10.4271/2016-01-0533.
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Ning, Fuda, Weilong Cong, Zhenyuan Jia, Fuji Wang e Meng Zhang. "Additive Manufacturing of CFRP Composites Using Fused Deposition Modeling: Effects of Process Parameters". In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8561.
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Fused deposition modeling (FDM) is one of the attractive additive manufacturing (AM) technologies for rapid prototyping with complex structures in a short timeframe. Thermoplastics are currently used as common feedstocks to fabricate prototypes in FDM process. However, FDM-fabricated pure thermoplastic parts cannot be used as load-bearing parts in the actual applications due to their limited tensile strength. Such condition could be improved by developing carbon fiber reinforced plastic (CFRP) composites using FDM for potential industrial end users. It is crucial that proper selections of FDM process parameters during fabricating CFRP composite parts could ensure the part quality and properties. However, the effects of FDM process parameters on the tensile properties of CFRP composites have not been explored. In this paper, CFRP composite specimens with 5 wt% carbon fiber content were fabricated using a FDM machine. Tensile testing was conducted to obtain the tensile properties. The effects of process parameters (including infill speed, nozzle temperature, and layer thickness) on the tensile properties of FDM-fabricated CFRP composite parts were investigated.
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Cheng, B., N. Moezi, D. Dideban, G. Roy, S. Roy e A. Asenov. "Benchmarking the Accuracy of PCA Generated Statistical Compact Model Parameters Against Physical Device Simulation and Directly Extracted Statistical Parameters". In 2009 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD). IEEE, 2009. http://dx.doi.org/10.1109/sispad.2009.5290230.
Texto completo da fonteRelatórios de organizações sobre o assunto "Compost process parameters"
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Crowley, David E., Dror Minz e Yitzhak Hadar. Shaping Plant Beneficial Rhizosphere Communities. United States Department of Agriculture, julho de 2013. http://dx.doi.org/10.32747/2013.7594387.bard.
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PGPR bacteria include taxonomically diverse bacterial species that function for improving plant mineral nutrition, stress tolerance, and disease suppression. A number of PGPR are being developed and commercialized as soil and seed inoculants, but to date, their interactions with resident bacterial populations are still poorly understood, and-almost nothing is known about the effects of soil management practices on their population size and activities. To this end, the original objectives of this research project were: 1) To examine microbial community interactions with plant-growth-promoting rhizobacteria (PGPR) and their plant hosts. 2) To explore the factors that affect PGPR population size and activity on plant root surfaces. In our original proposal, we initially prqposed the use oflow-resolution methods mainly involving the use of PCR-DGGE and PLFA profiles of community structure. However, early in the project we recognized that the methods for studying soil microbial communities were undergoing an exponential leap forward to much more high resolution methods using high-throughput sequencing. The application of these methods for studies on rhizosphere ecology thus became a central theme in these research project. Other related research by the US team focused on identifying PGPR bacterial strains and examining their effective population si~es that are required to enhance plant growth and on developing a simulation model that examines the process of root colonization. As summarized in the following report, we characterized the rhizosphere microbiome of four host plant species to determine the impact of the host (host signature effect) on resident versus active communities. Results of our studies showed a distinct plant host specific signature among wheat, maize, tomato and cucumber, based on the following three parameters: (I) each plant promoted the activity of a unique suite of soil bacterial populations; (2) significant variations were observed in the number and the degree of dominance of active populations; and (3)the level of contribution of active (rRNA-based) populations to the resident (DNA-based) community profiles. In the rhizoplane of all four plants a significant reduction of diversity was observed, relative to the bulk soil. Moreover, an increase in DNA-RNA correspondence indicated higher representation of active bacterial populations in the residing rhizoplane community. This research demonstrates that the host plant determines the bacterial community composition in its immediate vicinity, especially with respect to the active populations. Based on the studies from the US team, we suggest that the effective population size PGPR should be maintained at approximately 105 cells per gram of rhizosphere soil in the zone of elongation to obtain plant growth promotion effects, but emphasize that it is critical to also consider differences in the activity based on DNA-RNA correspondence. The results ofthis research provide fundamental new insight into the composition ofthe bacterial communities associated with plant roots, and the factors that affect their abundance and activity on root surfaces. Virtually all PGPR are multifunctional and may be expected to have diverse levels of activity with respect to production of plant growth hormones (regulation of root growth and architecture), suppression of stress ethylene (increased tolerance to drought and salinity), production of siderophores and antibiotics (disease suppression), and solubilization of phosphorus. The application of transcriptome methods pioneered in our research will ultimately lead to better understanding of how management practices such as use of compost and soil inoculants can be used to improve plant yields, stress tolerance, and disease resistance. As we look to the future, the use of metagenomic techniques combined with quantitative methods including microarrays, and quantitative peR methods that target specific genes should allow us to better classify, monitor, and manage the plant rhizosphere to improve crop yields in agricultural ecosystems. In addition, expression of several genes in rhizospheres of both cucumber and whet roots were identified, including mostly housekeeping genes. Denitrification, chemotaxis and motility genes were preferentially expressed in wheat while in cucumber roots bacterial genes involved in catalase, a large set of polysaccharide degradation and assimilatory sulfate reduction genes were preferentially expressed.
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Bajwa, Abdullah, e Timothy Jacobs. PR-457-17201-R02 Residual Gas Fraction Estimation Based on Measured Engine Parameters. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), fevereiro de 2019. http://dx.doi.org/10.55274/r0011558.
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Gas exchange processes in two-stroke internal combustion engines, commonly referred to as scavenging, are responsible for removing the exhaust gases in the combustion chamber and preparing the combustible fuel-oxidizer mixture that undergoes combustion and converts the chemical energy of the fuel into mechanical work. Scavenging is a complicated phenomenon because of the simultaneous introduction of fresh gases into the engine cylinder through the intake ports, and the expulsion of combustion products from the previous cycles through the exhaust ports. A non-negligible fraction of the gaseous mixture that is trapped in the cylinder at the conclusion of scavenging is composed of residual gases from the previous cycle. This can cause significant changes to the combustion characteristics of the mixture by changing its composition and temperature, i.e. its thermodynamic state. Thus, it is vital to have accurate knowledge of the thermodynamic state of the post-scavenging mixture to be able to reliably predict and control engine performance, efficiency and emissions. Two tools for estimating the trapped mixture state - a simple scavenging model and empirical correlations - were developed in this study. Unfortunately, it is not practical to directly measure the trapped residual fraction for engines operating in the field. To overcome this handicap, simple scavenging models or correlations, which estimate this fraction based on some economically measurable engine parameters, can be developed. This report summarizes the results of event-II of a multi-event project that aims to develop such mathematical formulations for stationary two-stroke natural gas engines using data from more advanced models and experimentation. In this event, results from a GT-Power based model for an Ajax E-565 single-cylinder engine are used to develop a three-event single zone scavenging model and empirical correlations. Both of these mathematical devices produce accurate estimates of the trapped mixture state. The estimates are compared to GT-Power results. In the next event of the project, these results will be validated using experimental data. Various steps followed in the development of the model have been discussed in this report, and at the end some results and recommendations for the next event of the project have been presented.
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Shmulevich, Itzhak, Shrini Upadhyaya, Dror Rubinstein, Zvika Asaf e Jeffrey P. Mitchell. Developing Simulation Tool for the Prediction of Cohesive Behavior Agricultural Materials Using Discrete Element Modeling. United States Department of Agriculture, outubro de 2011. http://dx.doi.org/10.32747/2011.7697108.bard.
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The underlying similarity between soils, grains, fertilizers, concentrated animal feed, pellets, and mixtures is that they are all granular materials used in agriculture. Modeling such materials is a complex process due to the spatial variability of such media, the origin of the material (natural or biological), the nonlinearity of these materials, the contact phenomenon and flow that occur at the interface zone and between these granular materials, as well as the dynamic effect of the interaction process. The lack of a tool for studying such materials has limited the understanding of the phenomena relevant to them, which in turn has led to energy loss and poor quality products. The objective of this study was to develop a reliable prediction simulation tool for cohesive agricultural particle materials using Discrete Element Modeling (DEM). The specific objectives of this study were (1) to develop and verify a 3D cohesionless agricultural soil-tillage tool interaction model that enables the prediction of displacement and flow in the soil media, as well as forces acting on various tillage tools, using the discrete element method; (2) to develop a micro model for the DEM formulation by creating a cohesive contact model based on liquid bridge forces for various agriculture materials; (3) to extend the model to include both plastic and cohesive behavior of various materials, such as grain and soil structures (e.g., compaction level), textures (e.g., clay, loam, several grains), and moisture contents; (4) to develop a method to obtain the parameters for the cohesion contact model to represent specific materials. A DEM model was developed that can represent both plastic and cohesive behavior of soil. Soil cohesive behavior was achieved by considering tensile force between elements. The developed DEM model well represented the effect of wedge shape on soil behavior and reaction force. Laboratory test results showed that wedge penetration resistance in highly compacted soil was two times greater than that in low compacted soil, whereas DEM simulation with parameters obtained from the test of low compacted soil could not simply be extended to that of high compacted soil. The modified model took into account soil failure strength that could be changed with soil compaction. A three dimensional representation composed of normal displacement, shear failure strength and tensile failure strength was proposed to design mechanical properties between elements. The model based on the liquid bridge theory. An inter particle tension force measurement tool was developed and calibrated A comprehensive study of the parameters of the contact model for the DEM taking into account the cohesive/water-bridge was performed on various agricultural grains using this measurement tool. The modified DEM model was compared and validated against the test results. With the newly developed model and procedure for determination of DEM parameters, we could reproduce the high compacted soil behavior and reaction forces both qualitatively and quantitatively for the soil conditions and wedge shapes used in this study. Moreover, the effect of wedge shape on soil behavior and reaction force was well represented with the same parameters. During the research we made use of the commercial PFC3D to analyze soil tillage implements. An investigation was made of three different head drillers. A comparison of three commonly used soil tillage systems was completed, such as moldboard plow, disc plow and chisel plow. It can be concluded that the soil condition after plowing by the specific implement can be predicted by the DEM model. The chisel plow is the most economic tool for increasing soil porosity. The moldboard is the best tool for soil manipulation. It can be concluded that the discrete element simulation can be used as a reliable engineering tool for soil-implement interaction quantitatively and qualitatively.
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Bajwa, Abdullah, e Timothy Jacobs. PR-457-17201-R01 Residual Gas Fraction Estimation Based on Measured In-Cylinder Pressure. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), setembro de 2018. http://dx.doi.org/10.55274/r0011519.
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Developing a reliable means of predicting and controlling engine operation at various operating conditions may be a reasonable pathway for meeting increasingly stringent engine emission regulations. In order to do so, estimates of the mixture composition at the end of the gas exchange process (i.e. at exhaust port closure, or EPC) are helpful for having accurate models of engine combustion. A substantial fraction of the trapped charge mixture is composed of residual gases from previous cycles. This fraction, the trapped residual fraction, changes combustion characteristics of the trapped mixture. Residual gases dilute the fresh charge, thus decreasing the flame speed and temperature. Moreover, because of their spatial inhomogeneity, especially around the spark plug, these gases seem to have implications for engine stability. All these factors likely affect engine performance and emissions. Unfortunately, it is not practical to directly measure the trapped residual fraction for engines operating in the field. To overcome this, computational models can be developed for control applications which estimate this fraction based on some measurable engine parameters e.g. manifold pressures, temperatures, etc. Currently, such models aren't readily available for stationary two-stroke natural-gas engines. This report summarizes the results of phase I of a multi-phase project. In this phase a GT-Power based model was developed for an Ajax E-565 single-cylinder engine to study various factors that influence the removal, or lack thereof, of residual gases from the engine cylinder. The model was used to successfully simulate various engine operating conditions and study the scavenging characteristics of the engine. Various steps followed in the development of the model have been discussed in the report, and at the end some preliminary results and recommendations for the next phase of the project have been presented.
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NUMERICAL SIMULATION ANALYSIS OF TEMPERATURE FIELD OF BOX-TYPE COMPOSITE WALL. The Hong Kong Institute of Steel Construction, agosto de 2022. http://dx.doi.org/10.18057/icass2020.p.321.
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The spatial and temporal characteristics of the internal temperature field of the box-type composite wall have great significance to high temperature mechanical response and fire resistance performance of composite wall subjected to fire. A series of assumptions for the simplified model were made after determining the influence of various thermal parameters, the boundary conditions of surface and the contact conditions. And the finite element software(ABAQUS) was used to establish the temperature field analysis model to conduct nonlinear transient temperature response analysis, then the validity of the model was verified by relevant test results. On this basis, the distribution of temperature field during the whole process and its key measuring points under fire are analyzed, and the parameters of each component are researched. The results show that the thickness of rock wool, the type, the thickness and number of layers of cladding plates have obvious influence on the temperature field distribution inside the composite wall, and other factors have little effect. According to the analysis results, the fire-resistant design idea of the composite wall and the temperature prediction formulas of the key temperature-control point are proposed, which provide the basis for the application of the boxtype steel structure system.
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A SURROGATE MODEL TO ESTIMATE THE AXIAL COMPRESSIVE CAPACITY OF COLD-FORMED STEEL OPEN BUILT-UP SECTIONS. The Hong Kong Institute of Steel Construction, agosto de 2022. http://dx.doi.org/10.18057/icass2020.p.316.
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This paper proposed a surrogate model to simplify the process of estimating the axial compressive capacity of cold-formed steel (CFS) open built-up sections composed of lipped channels with different section sizes, thickness, length, and connector spacing. The surrogate model was developed based on the current design methods, i.e., the Effective Width Method (EWM) and Direct Strength Method (DSM), which are codified in the North American Specification AISI S100-16. This new model features two surface regression equations with a boundary inequality criteria, anchored on two important parameters, i.e., modified slenderness ratio, (KL/r)m and minimum thickness-to-width ratio (t/w)min of the built-up sections. The model was validated with 1089 sets of the experimental results data collected from previous research tested on the axial capacity of CFS open built-up sections with the different design configurations. The proposed surrogate model is aimed to simplify the design process among practising engineers for a quick preliminary calculation of the axial compressive capacity of these new CFS open built-up sections.