977 resultados para optimization of production processes


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Zeaxanthin is an important natural pigment which has found commercial application in food and nutritional supplements. Its potential widespread use requires an easy and effective extraction methodology for obtaining higher yields. Extraction from Chlorella sp. under optimized conditions demonstrated a marked reduction in extraction time (13.48min) compared with a control experiment (30min). The extraction conditions such as solvent/cell dry weight (CDW) ratio, power, pulse, time and their combinations were optimized using response surface methodology (RSM). Almost all the variables were shown significantly (p-value <0.05) affect the carotenoid yield. Significant interaction (p-value <0.05) was observed with a substantial effect on zeaxanthin yield for solvent/CDW ratio and power, as well as power and time, whereas the β-carotene control exhibited significant interaction between solvent/CDW ratio and pulse, as well as between pulse and time. The R 2-value approached unity in both models, demonstrating their accuracy. Data obtained from these interactions were used to construct 3D response plots. Solvent/CDW ratio of 67.38μlmg-1, power 27.82% (total power 500W), pulse length of 19.7s and time 13.48min were found to be the optimized conditions for zeaxanthin (11.2mgg-1) and β-carotene (4.98mgg-1) extraction.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Healthcare-associated fungal outbreaks impose a substantial economic burden on the health system and typically result in high patient morbidity and mortality, particularly in the immunocompromised host. As the population at risk of invasive fungal infection continues to grow due to the increased burden of cancer and related factors, the need for hospitals to employ preventative measures has become increasingly important. These guidelines outline the standard quality processes hospitals need to accommodate into everyday practice and at times of healthcare-associated outbreak, including the role of antifungal stewardship programmes and best practice environmental sampling. Specific recommendations are also provided to help guide the planning and implementation of quality processes and enhanced surveillance before, during and after high-risk activities, such as hospital building works. Areas in which information is still lacking and further research is required are also highlighted.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A wide variety of evolutionary optimization algorithms have been used by researcher for optimal design of shell and tube heat exchangers (STHX). The purpose of optimization is to minimize capital and operational costs subject to efficiency constraints. This paper comprehensively examines performance of genetic algorithm (GA) and cuckoo search (CS) for solving STHX design optimization. While GA has been widely adopted in the last decade for STHX optimal design, there is no report on application of CS method for this purpose. Simulation results in this paper demonstrate that CS greatly outperforms GA in terms of finding admissible and optimal configurations for STHX. It is also found that CS method not only has a lower computational requirement, but also generates the most consistent results.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

AIM: To describe the protocol used to examine the processes of communication between health professionals, patients and informal carers during the management of oral chemotherapeutic medicines to identify factors that promote or inhibit medicine concordance. BACKGROUND: Ideally communication practices about oral medicines should incorporate shared decision-making, two-way dialogue and an equality of role between practitioner and patient. While there is evidence that healthcare professionals are adopting these concordant elements in general practice there are still some patients who have a passive role during consultations. Considering oral chemotherapeutic medications, there is a paucity of research about communication practices which is surprising given the high risk of toxicity associated with chemotherapy. DESIGN: A critical ethnographic design will be used, incorporating non-participant observations, individual semi-structured and focus-group interviews as several collecting methods. METHODS: Observations will be carried out on the interactions between healthcare professionals (physicians, nurses and pharmacists) and patients in the outpatient departments where prescriptions are explained and supplied and on follow-up consultations where treatment regimens are monitored. Interviews will be conducted with patients and their informal carers. Focus-groups will be carried out with healthcare professionals at the conclusion of the study. These several will be analysed using thematic analysis. This research is funded by the Department for Employment and Learning in Northern Ireland (Awarded February 2012). DISCUSSION: Dissemination of these findings will contribute to the understanding of issues involved when communicating with people about oral chemotherapy. It is anticipated that findings will inform education, practice and policy.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In recent years, aquaculture has been facing a series of new issues, including the necessary replacement of fish oil and fish meal because of their limited supply and sub-optimal water temperature conditions. Higher water temperatures are increasingly encountered as the result of climate change related phenomena and/or the practice of farming of species in areas with environmental characteristics outside their optimal physiological range, such as the case of Atlantic salmon (. Salmo salar) farming in Australia during the summer season. Previous studies in teleost fish have shown that when fish are exposed at higher environmental temperatures, fish had a preferential increased dietary intake for arachidonic acid (20:4n - 6, ARA). This observation suggests that, given the several metabolic roles of ARA, its dietary provision may play an important role in fish for adapting at sub-optimal high water temperatures. The objective of this study was therefore to evaluate the effects of different dietary ARA/EPA ratios in juvenile Atlantic salmon as affected by time of exposition to the diet and water temperatures, with particular focus to fish performance and possible resulting modifications of tissue fatty acid composition. The study showed that independently from dietary treatments, fish held at the higher temperatures had an increased ARA accumulation, primarily in the liver and this ARA accumulation increased over time. It was also shown that the combined dietary inclusion of ARA and EPA significantly improved fish performance, compared with diets either richer in ARA or EPA. A general trend toward higher content of n - 3 LC-PUFA at lower temperatures was also quite clear, especially in the liver. Therefore, and assuming that the trends in tissue fatty acid composition could be taken as a clue of the optimal fatty acid requirements of fish, the n - 6 requirement (and in particular ARA) clearly appears to be greater for Atlantic salmon raised at high water temperatures. Protein accumulation was higher in the diet with the combined dietary inclusion of ARA and EPA for fish held at high water temperature (20. °C), with a concomitant lipid reduction. This study shows the importance of dietary ARA for maximal growth in Atlantic salmon, particularly during the period of the year when high water temperatures are often encountered. Further studies specifically looking at optimal dietary ARA/EPA ratio and roles of ARA on myogenesis, stress physiology and immune status of cultured fish are warranted. Statement of relevance: Given the current high level of fish oil replacement in aquafeed, and the often encountered sub-optimal environmental temperatures, we believe that this study could be considered as timely and highly pertinent for the aquaculture industry and associated R&D sector.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

 Novel computational intelligence-based methods have been investigated to quantify uncertainties prevalent in the operation of chemical plants. A new family of predication interval-based controlling algorithms is proposed and successfully applied to chemical reactors in order to minimise energy consumption and operational cost.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Software-Defined Network (SDN) is a promising network paradigm that separates the control plane and data plane in the network. It has shown great advantages in simplifying network management such that new functions can be easily supported without physical access to the network switches. However, Ternary Content Addressable Memory (TCAM), as a critical hardware storing rules for high-speed packet processing in SDN-enabled devices, can be supplied to each device with very limited quantity because it is expensive and energy-consuming. To efficiently use TCAM resources, we propose a rule multiplexing scheme, in which the same set of rules deployed on each node apply to the whole flow of a session going through but towards different paths. Based on this scheme, we study the rule placement problem with the objective of minimizing rule space occupation for multiple unicast sessions under QoS constraints. We formulate the optimization problem jointly considering routing engineering and rule placement under both existing and our rule multiplexing schemes. Via an extensive review of the state-of-the-art work, to the best of our knowledge, we are the first to study the non-routing-rule placement problem. Finally, extensive simulations are conducted to show that our proposals significantly outperform existing solutions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Application of optimization algorithm to PDE modeling groundwater remediation can greatly reduce remediation cost. However, groundwater remediation analysis requires a computational expensive simulation, therefore, effective parallel optimization could potentially greatly reduce computational expense. The optimization algorithm used in this research is Parallel Stochastic radial basis function. This is designed for global optimization of computationally expensive functions with multiple local optima and it does not require derivatives. In each iteration of the algorithm, an RBF is updated based on all the evaluated points in order to approximate expensive function. Then the new RBF surface is used to generate the next set of points, which will be distributed to multiple processors for evaluation. The criteria of selection of next function evaluation points are estimated function value and distance from all the points known. Algorithms created for serial computing are not necessarily efficient in parallel so Parallel Stochastic RBF is different algorithm from its serial ancestor. The application for two Groundwater Superfund Remediation sites, Umatilla Chemical Depot, and Former Blaine Naval Ammunition Depot. In the study, the formulation adopted treats pumping rates as decision variables in order to remove plume of contaminated groundwater. Groundwater flow and contamination transport is simulated with MODFLOW-MT3DMS. For both problems, computation takes a large amount of CPU time, especially for Blaine problem, which requires nearly fifty minutes for a simulation for a single set of decision variables. Thus, efficient algorithm and powerful computing resource are essential in both cases. The results are discussed in terms of parallel computing metrics i.e. speedup and efficiency. We find that with use of up to 24 parallel processors, the results of the parallel Stochastic RBF algorithm are excellent with speed up efficiencies close to or exceeding 100%.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Data available on continuos-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the use of Martingale Estimating Functions and the application of Generalized Method of Moments (GMM).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Data available on continuous-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the employment of Martingale Estimating Functions, and the application of Generalized Method of Moments (GMM).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Por muito tempo, os programas de qualidade e gestão vêm dominando o cenário de soluções para a melhoria das organizações. Nesse contexto, têm sido constantes os modismos e, ao mesmo tempo, o consumo de muitas soluções. E o mercado parece se nutrir desses pacotes. De pacote em pacote, a gestão nas companhias vem se desenvolvendo e se especializando e, junto como isso, os métodos e técnicas da boa gestão. A gestão de riscos, especificamente, vem nesse contexto. Apresenta-se como uma solução em gestão, mas parece se estabelecer como ponto de convergência e de influência na otimização e garantia de processos produtivos, de gestão e de suporte, abrangendo uma gama de possibilidades em diversas disciplinas do mundo empresarial, desde finanças até os aspectos de fraudes e distúrbios cotidianos. Na sequência da gestão de riscos, vem a gestão de crises. Esta, o hemisfério dos riscos transformados em impactos verdadeiros e com danos visíveis para a organização. A gestão de crises pressupõe a gestão dos riscos consumados e que, claramente, afetam a organização e seu contexto, tanto interno quanto externo. No ponto final dessa lógica, aparece a confiança como aquilo que sela o pacto da organização e seus stakeholders, como resultado da boa ou má gestão de riscos e crises. Este estudo é, então, sobre riscos, crises e confiança e sobre o entendimento de como a gestão sobrepõe esses elementos e como isso se aplica às organizações, especificamente a uma grande organização do mercado brasileiro. Após revisão bibliográfica, é feita uma pesquisa para se analisar como está sendo a aplicação dos conceitos e práticas de riscos e crises em uma grande empresa, entrevistando-se o principal executivo da companhia responsável pela gestão de riscos na área de segurança da informação e outro responsável pela gestão de crises. É feita uma pesquisa para se entender a percepção de empregados e gerentes da companhia estudada sobre os conceitos e práticas de gestão de riscos e crises e suas aplicações na companhia. Também é feita uma abordagem sobre confiança, extrapolando-se esse conceito para uma idéia de confiabilidade dessas práticas e propondo uma forma de medir essa confiabilidade, identificada como uma lacuna na gestão de crises. Ao final, é feita uma análise sobre o quanto a aplicação desses conceitos e práticas são sistemáticos ou não, de acordo com as hipóteses e suposições definidas, constatando-se o 9 caráter operacional e a aplicação recente das práticas, um tanto deslocada do modelo de referência proposto para o estudo e com pouca visibilidade por parte dos empregados, principalmente no que tange a percepção de efetividade das práticas adotadas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper uses an output oriented Data Envelopment Analysis (DEA) measure of technical efficiency to assess the technical efficiencies of the Brazilian banking system. Four approaches to estimation are compared in order to assess the significance of factors affecting inefficiency. These are nonparametric Analysis of Covariance, maximum likelihood using a family of exponential distributions, maximum likelihood using a family of truncated normal distributions, and the normal Tobit model. The sole focus of the paper is on a combined measure of output and the data analyzed refers to the year 2001. The factors of interest in the analysis and likely to affect efficiency are bank nature (multiple and commercial), bank type (credit, business, bursary and retail), bank size (large, medium, small and micro), bank control (private and public), bank origin (domestic and foreign), and non-performing loans. The latter is a measure of bank risk. All quantitative variables, including non-performing loans, are measured on a per employee basis. The best fits to the data are provided by the exponential family and the nonparametric Analysis of Covariance. The significance of a factor however varies according to the model fit although it can be said that there is some agreements between the best models. A highly significant association in all models fitted is observed only for nonperforming loans. The nonparametric Analysis of Covariance is more consistent with the inefficiency median responses observed for the qualitative factors. The findings of the analysis reinforce the significant association of the level of bank inefficiency, measured by DEA residuals, with the risk of bank failure.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

FERNANDES, Fabiano A. N. et al. Optimization of Osmotic Dehydration of Papaya of followed by air-drying. Food Research Internation, v. 39, p. 492-498, 2006.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

O objetivo deste trabalho foi avaliar o efeito do choque térmico e mecânico na produtividade de Lentinula edodes em 140 toras de Eucalyptus saligna, completamente colonizadas pelo fungo, em diferentes tempos de imersão em água e no primeiro fluxo de produção. As toras foram imersas em água resfriada (16ºC) ou à temperatura ambiente (22ºC); os períodos de imersão corresponderam a 6, 10, 14, 18, 22, 26 e 38 horas; o choque mecânico foi acompanhado por três quedas consecutivas da tora, em posição vertical, no chão. A temperatura da água e o tempo de imersão afetaram a produção de L. edodes, resultando em aumentos significativos (2 a 4 vezes) nos tratamentos em que as toras foram submetidas à água resfriada e nos tempos de imersão mais curtos (6 e 10 horas). O choque mecânico não resultou em aumento na produção de basidiomas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)