Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 123
Primeira ... 1234567 ... Última
Imagem não selecionada

Imprime registro no formato completo
A Comparison of Timber Models for Use in Public Policy Analysis AgEcon
Sohngen, Brent; Sedjo, Roger A..
In this paper, we compare and contrast two types of timber models that have been used for public policy analysis. These models have been variously used to predict price, inventory and market welfare impacts under different exogenous forces that impact timber markets. The framework and theory for each model type is presented and discussed. We then thoroughly test the two model types across six potential exogenous shocks to timber markets, ranging from instantaneous demand shocks to gradual supply adjustments. Our comparison indicates that these models predict potentially important differences in timber market behavior. These differences are important to consider for those who do public policy analysis.
Tipo: Working or Discussion Paper Palavras-chave: Timber markets; Models; Dynamic adjustment; Optimization; Resource /Energy Economics and Policy; C62; Q21; Q23.
Ano: 1996 URL: http://purl.umn.edu/10467
Imagem não selecionada

Imprime registro no formato completo
A Flexible Inventory Model for MSW Recycling AgEcon
Louis, Garrick; Shih, Jhih-Shyang.
Most of the United States have laws mandating the recycling of municipal solid waste (MSW). In order to comply, municipalities recycle quotas of materials, without regard to fluctuating prices. An inventory system is proposed that allows municipalities to be sensitive to materials prices as they recycle in accordance with state mandates. A dynamic model is developed; it uses historical secondary material prices as exogenous inputs to minimize the net present value of MSW recycling system cost. The model provides a cost-effective method for municipalities to achieve their MSW recycling targets. The savings is approximately $1.43 per ton of MSW generated based on total MSW management costs of $13.5 per ton. The model also allows one to investigate the...
Tipo: Working or Discussion Paper Palavras-chave: Municipal solid waste; Recycling; Inventory; Optimization; Environmental Economics and Policy; Q2.
Ano: 2002 URL: http://purl.umn.edu/10459
Imagem não selecionada

Imprime registro no formato completo
A Mathematical Model for the Removal of Organic Mater in Stabilization Ponds BABT
Medri,Waldir; Medri,Vandir.
This work presents an application to systemize the construction of ponds systems for treatment of domestic sewage. It consisted of two anaerobic ponds operated in parallel during May/97 to April/99. These were connected in series with a chicaned facultative pond. The treatment system was controlled with samples collected from the crude sewage (compound sample), in the affluents and effluents of the ponds and along the flux of the anaerobic and facultative ponds. The following parameters were analyzed: pH, Biochemical Oxygen Demand, Chemical Oxygen Demand, Total Solids, Sedimentable Solids, Total Coliforms, Oxygen Consumed in Acid Medium (OCAM) and temperature.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Stabilization ponds; Mathematical model; Optimization.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000100014
Imagem não selecionada

Imprime registro no formato completo
A simplified Excel® algorithm for estimating the least limiting water range of soils Scientia Agricola
Leão,Tairone Paiva; Silva,Alvaro Pires da.
The least limiting water range (LLWR) of soils has been employed as a methodological approach for evaluation of soil physical quality in different agricultural systems, including forestry, grasslands and major crops. However, the absence of a simplified methodology for the quantification of LLWR has hampered the popularization of its use among researchers and soil managers. Taking this into account this work has the objective of proposing and describing a simplified algorithm developed in Excel® software for quantification of the LLWR, including the calculation of the critical bulk density, at which the LLWR becomes zero. Despite the simplicity of the procedures and numerical techniques of optimization used, the nonlinear regression produced reliable...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nonlinear regression; Spreadsheet software; Optimization; Soil physics; Soil quality.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000600013
Imagem não selecionada

Imprime registro no formato completo
A Watershed-Based Economic Model of Alternative Management Practices in Southern Agricultural Systems AgEcon
Paudel, Krishna P.; Hite, Diane; Intarapapong, Walaiporn; Susanto, Dwi.
We investigated the environmental impacts of alternative cultural practices within a watershed under different water quality standards. We used experimental data on nutrient runoff to determine the optimal amount of broiler litter application in hay production in Louisiana. To compensate for the lack of experimental data, we used biophysical simulation models to find the optimal combination of agricultural best-management practices in a watershed in Mississippi. The results indicated that stricter environmental standards lower total profit potential and litter utilization.
Tipo: Journal Article Palavras-chave: Broiler litter; Cropping systems; Optimization; Watershed level modeling; Water quality; C6; Q1; Q25; D21.
Ano: 2003 URL: http://purl.umn.edu/43213
Imagem não selecionada

Imprime registro no formato completo
Adjustment of mathematical models and quality of soybean grains in the drying with high temperatures AGRIAMBI
Coradi,Paulo C.; Fernandes,Carlos H. P.; Helmich,Jean C..
ABSTRACT The aim of this study was to evaluate the influence of the initial moisture content of soybeans and the drying air temperatures on drying kinetics and grain quality, and find the best mathematical model that fit the experimental data of drying, effective diffusivity and isosteric heat of desorption. The experimental design was completely randomized (CRD), with a factorial scheme (4 x 2), four drying temperatures (75, 90, 105 and 120 ºC) and two initial moisture contents (25 and 19% d.b.), with three replicates. The initial moisture content of the product interferes with the drying time. The model of Wang and Singh proved to be more suitable to describe the drying of soybeans to temperature ranges of the drying air of 75, 90, 105 and 120 °C and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dimensioning; Optimization; Post-harvest..
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000400385
Imagem não selecionada

Imprime registro no formato completo
An Assessment of the Precision and Confidence of Aquatic Eddy Correlation Measurements ArchiMer
Donis, Daphne; Holtappels, Moritz; Noss, Christian; Cathalot, Cecile; Hancke, Kasper; Polsenaere, Pierre; Wenzhoefer, Frank; Lorke, Andreas; Meysman, Filip J. R.; Glud, Ronnie N.; Mcginnis, Daniel F..
The quantification of benthic fluxes with the aquatic eddy correlation (EC) technique is based on simultaneous measurement of the current velocity and a targeted bottom water parameter (e.g., O2, temperature). High-frequency measurements (64 Hz) are performed at a single point above the seafloor using an acoustic Doppler velocimeter (ADV) and a fast-responding sensor. The advantages of aquatic EC technique are that 1) it is noninvasive, 2) it integrates fluxes over a large area, and 3) it accounts for in situ hydrodynamics. The aquatic EC has gained acceptance as a powerful technique; however, an accurate assessment of the errors introduced by the spatial alignment of velocity and water constituent measurements and by their different response times is...
Tipo: Text Palavras-chave: Turbulence; Boundary layer; Fluxes; Instrumentation/sensors; Optimization; Experimental design.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00275/38577/37102.pdf
Imagem não selecionada

Imprime registro no formato completo
An empirical comparison of different risk measures in portfolio optimization AgEcon
Hoe, Lam Weng; Saiful Hafizah, Jaaman; Zaidi, Isa.
Risk is one of the important parameters in portfolio optimization problem. Since the introduction of the mean-variance model, variance has become the most common risk measure used by practitioners and researchers in portfolio optimization. However, the mean-variance model relies strictly on the assumptions that assets returns are multivariate normally distributed or investors have a quadratic utility function. Many studies have proposed different risk measures to overcome the drawbacks of variance. The purpose of this paper is to discuss and compare the portfolio compositions and performances of four different portfolio optimization models employing different risk measures, specifically the variance, absolute deviation, minimax and semi-variance. Results...
Tipo: Journal Article Palavras-chave: Portfolio; Optimization; Risk measures; Variance.; Financial Economics; CO2; C61; G11.
Ano: 2010 URL: http://purl.umn.edu/95934
Imagem não selecionada

Imprime registro no formato completo
Analysis of profitability and risk in new agriculture in a Himalayan watershed by using dynamic non-linear programming model AgEcon
Sharma, Rakesh Kumar; Sankhayan, Prem Lall; Singh, Ranveer.
Cropping pattern in the Himalayan region of India has undergone a significant change in the recent past. Introduction of horticultural crops of vegetables, fruits and flowers have led to more intensive agriculture. Such a change, resulting in higher incomes and improvements of the overall living conditions has, however, been accompanied with increased income risk. This emphasises a need for proper analysis of the cropping pattern, at an appropriate scale, such as, a micro watershed. This was achieved by constructing a dynamic non-linear programming model incorporating appropriate objective function, constraints and crop and livestock activity budgets along with risk component present in the gross returns. The model was then solved under alternate policy...
Tipo: Conference Paper or Presentation Palavras-chave: Cropping pattern; Gross margins; Himachal Pradesh; Optimization; Covariance; Crop Production/Industries; Farm Management; Research Methods/ Statistical Methods; Resource /Energy Economics and Policy; Risk and Uncertainty; C61; Q12; Q15.
Ano: 2009 URL: http://purl.umn.edu/51404
Imagem não selecionada

Imprime registro no formato completo
Ananalysis on Runtime Associated QOS-Based Proficient Web Services Discovery Optimization BABT
Amirthasaravanan,A.; Rodrigues,Paul; Sudhesh,R..
ABSTRACT In today's web world, Service-oriented architectures represent the main standard for IT infrastructures. Certainly, with the initiation of service oriented architecture, Web services have gained incredible growth. Web service discovery has become increasingly more significant as the existing use of web service. Discovering most appropriate web service from vast collection of web services is very decisive for successful execution of applications. In automation of web service discovery, there is always a need to deem Quality of Service (QoS) attributes during matching. A study of literature concerning the evolution of different web service discovery optimization methods with unique prominence to quality motivated service discovery have been carried...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Web Services; Service-Oriented Architectures; Discovery; Quality of Service; Bio-Inspired Algorithm; Metaheuristics; Optimization.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132016000300601
Imagem não selecionada

Imprime registro no formato completo
Anthocyanins from blackberry (Rubus fructicosus L.) impregnated in yam bean (Pachyrhizus erosus (L.) Urb.) by osmotic dehydration Ciênc. Tecnol. Aliment.
GRAJALES-LAGUNES,Alicia; CABRERA-RUIZ,Luis; GUTIÉRREZ-MICELI,Federico; RUIZ-CABRERA,Miguel Angel; DENDOOVEN,Luc; ABUD-ARCHILA,Miguel.
Abstract Yam bean (Pachyrhizus erosus (L.) Urb.) tuber has a low carbohydrate content and contains several aminoacids, but contains few active compounds, such as vitamins and antioxidants. Anthocyanins are antioxidants found in Rubus fructicosus L. The osmotic drying is a technique that can be used to impregnate antioxidants in a matrix, so the objective of this study was to impregnate yam bean tuber slices with anthocyanin. The effect of temperature (40, 50 and 60oC), sucrose content (40, 50 and 60oBrix) and vacuum pulse (0, 300 and 600 mbar) on water loss (WL), solid gain (SG), color changes (ΔΕ) and anthocyanin concentration (ΔA) during osmotic drying of yam bean slices was determined. Polynomial equations were used to determine changes in WL, SG, ΔΕ...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anthocyanin; Impregnation; Optimization; Osmotic drying; Yam bean.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000400922
Imagem não selecionada

Imprime registro no formato completo
Application of simulated annealing in simulation and optimization of drying process of Zea mays malt REA
Benvenga,Marco A. C.; Araújo,Sidnei A. de; Librantz,André F. H.; Santana,José C. C.; Tambourgi,Elias B..
Kinetic simulation and drying process optimization of corn malt by Simulated Annealing (SA) for estimation of temperature and time parameters in order to preserve maximum amylase activity in the obtained product are presented here. Germinated corn seeds were dried at 54-76 °C in a convective dryer, with occasional measurement of moisture content and enzymatic activity. The experimental data obtained were submitted to modeling. Simulation and optimization of the drying process were made by using the SA method, a randomized improvement algorithm, analogous to the simulated annealing process. Results showed that seeds were best dried between 3h and 5h. Among the models used in this work, the kinetic model of water diffusion into corn seeds showed the best...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Simulated annealing; Zea mays; Drying curves; Optimization; Simulation.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000500012
Imagem não selecionada

Imprime registro no formato completo
Applications of Plackett–Burman and Central Composite Design for the Optimization of Novel Brevundimonas diminuta KT277492 Chitinase Production, Investigation of its Antifungal Activity BABT
Warda,E. Ashour; Abeer,A. Abd El Aty; Eman,R. Hamed; Mahmoud,A. Swelim; Ahmed,I. El-Diwany.
ABSTRACT Biological control strategy which can damage chitin, a vital component of pathogenic fungi and arthropods promises a safe solution for many fungal problems. And it’s more favorable than chemicals which increase health risks and environmental problems. Thus, the chitinase producers appear potential candidates of biological control of pathogenic fungi. Brevundimonus diminuta KT277492 is a new isolate that has been isolated recently from Egyptian soil. Significant factors that affecting the chitinase enzyme production were studied and optimized using Plackett-Burman and Response Surface Methodology (RSM). As a result, maximum production of chitinase enzyme was 832.87 IUL-1, this result presented about 8.767-fold increase in the enzyme production. In...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chitinase; Brevundimonas diminuta KT277492; Optimization; Plackett–Burman; Central composite design; Antifungal.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132016000100429
Imagem não selecionada

Imprime registro no formato completo
Avaliação da viabilidade técnica e econômica da utilização de biomassas como fonte energética alternativa em fornos industriais AgEcon
Lima, Lilian Maluf de; Oliveira, Ana Maria Kefalas; Carletti, Paulo de Tarso Filho; Ferrari, Renata Cristina; Caixeta, Jose Vicente Filho.
This study, conducted along the year 2003, was held in the environment of a cement company plant located in the São Paulo State. That industry has used carbon black as predominant energetic source which besides resulting a huge emission of gases (CO and CO2) into the atmosphere, has been more expensive than some other alternatives of biomass sources. Taking into consideration the location of that plant, there was a large supply of available biomass to be used as alternative fuel for industrial ovens. Several biomasses were analyzed and it was concluded that the sugar cane bagasse and residues of wood (sawdust and woodchips) were the most appropriate alternatives to such an industry.
Tipo: Journal Article Palavras-chave: Biomass; Energy; Transport; Optimization; Resource /Energy Economics and Policy.
Ano: 2006 URL: http://purl.umn.edu/55310
Imagem não selecionada

Imprime registro no formato completo
Bacterial Resistance and the Optimal Use of Antibiotics AgEcon
Laxminarayan, Ramanan.
The increasing resistance of harmful biological organisms (bacteria, parasites, and pests) to selection pressure from the widespread use of control agents such as antibiotics, antimalarials, and pesticides is a serious problem in both medicine and agriculture. Modeling resistance-or, conversely, the effectiveness of these control agents as a biological resource-yields insights into how these agents should be optimally managed to maximize their economic benefit to society. This paper uses a model of evolution of bacterial resistance to antibiotics-in which resistance places an evolutionary disadvantage on the resistant organism-to develop a simple sequential algorithm of optimal antibiotic use. Although the solution to this problem follows the...
Tipo: Working or Discussion Paper Palavras-chave: Antibiotic resistance; Natural resource; Optimization; Health Economics and Policy; I0; Q0.
Ano: 2001 URL: http://purl.umn.edu/10479
Imagem não selecionada

Imprime registro no formato completo
Batch and continuous extraction of bromelain enzyme by reversed micelles BABT
Fileti,Ana Maria Frattini; Fischer,Gilvan Anderson; Santana,José Carlos Curvelo; Tambourgi,Elias Basile.
The main aim of this study was to optimize the conditions for bromelain extraction by reversed micelles from pineapple juice (Ananas comosus). The purification was carried out in batch extraction and a micro-column with pulsed caps for continuous extraction. The cationic micellar solution was made of BDBAC as a surfactant, isooctane as a solvent and hexanol as a co-solvent. For the batch process, a purification factor of 3 times at the best values of surfactant agent, co-solvent and salt concentrations, pH of the back and forward extractions were, 100 mM, 10% v/v, 1 M, 3.5 and 8, respectively. For the continuous operation, independent variables optimal point was determined: ratio between light phase flow rate and total flow rate equal to 0.67 and 1 second...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Reversed micelles; Liquid-liquid extraction; Bromelain; Pineapple; Optimization; Surface response.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000500021
Imagem não selecionada

Imprime registro no formato completo
Behaviour of a floc population during a tidal cycle: laboratory experiments and numerical modelling ArchiMer
Verney, Romaric; Lafite, Robert; Brun-cottan, Jean Claude; Le Hir, Pierre.
An approach combining laboratory experiments and numerical modelling was used to investigate the behaviour of a floc population during an idealized tidal cycle. The experiment was conducted on suspended sediments at a concentration of 93 mg l−1 collected in the field. It was based on a jar test device to reproduce tidal-induced turbulence and coupled with a CCD camera system and image post-processing software to monitor floc size distribution. At the same time, a 0D size-class based aggregation/fragmentation model (FLOCMOD) was developed to simulate changes in the floc population over the tidal cycle. Experimental results revealed strong variability of the behaviour of microfloc and macrofloc populations with respect to the varying shear rates observed in...
Tipo: Text Palavras-chave: Flocculation; Tidal cycle; Laboratory experiment; FLOCMOD; OD model; Sensitivity analysis; Optimization.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00027/13846/11020.pdf
Imagem não selecionada

Imprime registro no formato completo
Biological Limits on Agricultural Intensification: An Example from Resistance Management AgEcon
Laxminarayan, Ramanan; Simpson, R. David.
When the application of pesticides places selective evolutionary pressure on pest populations, it can be useful to plant refuge areas-crop areas intended to encourage the breeding of pests that are susceptible to the pesticide. Renewed interest in refuge areas has arisen with recent advances in biotechnology and genetically modified (GM) crops. In this paper, we use a simple model of the evolution of pest resistance to characterize the socially optimal refuge strategy for managing pest resistance. We demonstrate some interesting analogies with other models of renewable resource management, such as those of fisheries. Among the analogous results are findings that maintaining what we might call "maximal sustainable susceptibility" is typically not...
Tipo: Working or Discussion Paper Palavras-chave: Pest resistance; Biotechnology; Optimization; Research and Development/Tech Change/Emerging Technologies; Q1; Q2.
Ano: 2000 URL: http://purl.umn.edu/10914
Imagem não selecionada

Imprime registro no formato completo
Cable length optimization for trawl fuel consumption reduction ArchiMer
Khaled, Ramez; Priour, Daniel; Billard, Jean-yves.
A numerical method for optimization of the cable lengths in trawls with respect to the ratio between the estimated trawl drag and the predicted catch efficiency is developed and applied. The trawl cables of interest are warps, bridles, headline and footrope. The optimization algorithm applies an ordered sequential process changing one cable length at the time. It is assumed in the predictions that the catch efficiency of the trawl is proportional with the trawl mouth area. In a case study optimizing a bottom trawl used on a research vessel by applying the new method it is predicted that it would be possible to reduce the ratio between trawl drag and catch efficiency by up to 46% by optimizing the cable lengths. Thus this would enable a considerable...
Tipo: Text Palavras-chave: Bottom trawl; Modeling; Optimization; Fuel consumption; Drag; Swept area; Mouth surface; Fish distribution.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00130/24106/22857.pdf
Imagem não selecionada

Imprime registro no formato completo
Carbon conversion efficiency and population dynamics of a marine algae–bacteria consortium growing on simplified synthetic digestate: First step in a bioprocess coupling algal production and anaerobic digestion ArchiMer
Vasseur, Christophe; Bougaran, Gael; Garnier, Matthieu; Hamelin, Jérôme; Leboulanger, Christophe; Le Chevanton, Myriam; Mostajir, Behzad; Sialve, Bruno; Steyer, Jean-philippe; Fouilland, Eric.
Association of microalgae culture and anaerobic digestion seems a promising technology for sustainable algal biomass and biogas production. The use of digestates for sustaining the growth of microalgae reduces the costs and the environmental impacts associated with the substantial algal nutrient requirements. A natural marine algae–bacteria consortium was selected by growing on a medium containing macro nutrients (ammonia, phosphate and acetate) specific of a digestate, and was submitted to a factorial experimental design with different levels of temperature, light and pH. The microalgal consortium reached a maximum C conversion efficiency (i.e. ratio between carbon content produced and carbon supplied through light photosynthetic C conversion and acetate)...
Tipo: Text Palavras-chave: Optimization; Nannochloris; Heterotrophic bacteria; Anaerobic digestion; Bioenergy.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00085/19642/17419.pdf
Registros recuperados: 123
Primeira ... 1234567 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional