Diseño para operabilidad: Una revisión de enfoques y estrategias de solución

In the last decades the chemical engineering scientific research community has largely addressed the design-foroperability problem. Such an interest responds to the fact that the operability quality of a process is determined by design, becoming evident the convenience of considering operability issues in early design stages rather than later when the impact of modifications is less effective and more expensive. The necessity of integrating design and operability is dictated by the increasing complexity of the processes as result of progressively stringent economic, quality, safety and environmental constraints. Although the design-for-operability problem concerns to practically every technical discipline, it has achieved a particular identity within the chemical engineering field due to the economic magnitude of the involved processes. The work on design and analysis for operability in chemical engineering is really vast and a complete review in terms of papers is beyond the scope of this contribution. Instead, two major approaches will be addressed and those papers that in our belief had the most significance to the development of the field will be described in some detail.En las últimas décadas, la comunidad científica de ingeniería química ha abordado intensamente el problema de diseño-para-operabilidad. Tal interés responde al hecho de que la calidad operativa de un proceso esta determinada por diseño, resultando evidente la conveniencia de considerar aspectos operativos en las etapas tempranas del diseño y no luego, cuando el impacto de las modificaciones es menos efectivo y más costoso. La necesidad de integrar diseño y operabilidad esta dictada por la creciente complejidad de los procesos como resultado de las cada vez mayores restricciones económicas, de calidad de seguridad y medioambientales. Aunque el problema de diseño para operabilidad concierne a prácticamente toda disciplina, ha adquirido una identidad particular dentro de la ingeniería química debido a la magnitud económica de los procesos involucrados. El trabajo sobre diseño y análisis para operabilidad es realmente vasto y una revisión completa en términos de artículos supera los alcances de este trabajo. En su lugar, se discutirán los dos enfoques principales y aquellos artículos que en nuestra opinión han tenido mayor impacto para el desarrollo de la disciplina serán descriptos con cierto detalle.Fil: Blanco, Anibal Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Dynamic Modelling and Optimisation of Large-Scale Cryogenic Separation Processes

In this work, the open loop dynamic optimisation of a large-scale natural gas processing plant is performed. A rigorous differential-algebraic equation (DAE) model has been formulated to represent main plant units, such as shell and tube heat exchangers, highpressure separator and demethanizing column. In the shell and tube heat exchangers, the hot stream partially condenses and equations to consider the partial condensation of the fluids have been included. A rigorous index one model for the demethanizing column has been developed. The DAE optimisation problem is solved with a simultaneous approach, in which both state and control variables are discretised and the original DAE optimisation model is transformed into a large-scale nonlinear problem (NLP), which is solved using Sequential Quadratic Programming (SQP) methods. Optimal profiles have been obtained for main operating variables to achieve an enhanced product recovery.Fil: Rodriguez, Mariela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Díaz, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Consumer Attitudes toward Milk Products Produced from Cloned Cows

The use of simulated test-marketing technology and concept exposure for a branded and priced milk product shows that consumers had similar purchase interest for the full-priced product and the product offered at a 25-percent discount when they were told that the reason for the discount was that the product was produced using biotechnology. Furthermore, there was a slight reduction in purchase interest in the discounted milk when consumers were told that the product was from cloned cows. However, when consumers were offered the conventional product at the market price and they were later told that the product was from cloned cows, the purchase interest dropped from 25 percent to only 6.3 percent. Thus if producers adopt the cloning process and do not educate the consumers and pass along the benefits of lower-priced milk, it appears that consumers will react negatively when they learn of the change in production method and may purchase a different brand or type of milk.Food Consumption/Nutrition/Food Safety,

The quality of meals in companies participating in the worker's food program in the city of São Paulo, Brazil

OBJETIVO: Avaliar a qualidade global das refeições oferecidas por Unidades de Alimentação e Nutrição de empresas beneficiárias do Programa de Alimentação do Trabalhador, na cidade de São Paulo. MÉTODOS: Estudo transversal realizado com 72 empresas cadastradas no programa. Foram coletadas informações de três dias consecutivos das refeições oferecidas no almoço, no jantar e na ceia. A qualidade das refeições oferecidas foi avalia pelo Índice de Qualidade da Refeição, e sua análise foi feita de forma estratificada segundo o perfil da empresa obtido pela análise de cluster. RESULTADOS: A média do Índice de Qualidade da Refeição para as grandes refeições foi de 66,25. Foram obtidos dois grupos de empresas na análise de cluster. As empresas do primeiro, composto em sua maioria por empresas do setor de comércio de micro e pequeno porte, cadastradas na modalidade de autogestão e sem supervisão de nutricionista, obtiveram pior qualidade da refeição (Índice=56,23). As empresas do segundo cluster, constituído principalmente por empresas de médio e grande porte do setor industrial, com gestão terceirizada e supervisão de nutricionista, obtiveram pontuação média do Índice de 82,95. CONCLUSÃO: As refeições oferecidas pelas empresas participantes do Programa de Alimentação do Trabalhador não estavam adequadas, segundo o Índice de Qualidade da Refeição. As empresas de menor porte e estrutura tiveram refeições de pior qualidade quando comparadas com as demais, demonstrando que empresas deste perfil são prioritárias para intervenções dentro do Programa de Alimentação do Trabalhador.OBJECTIVE: The aim of this study was to assess the global quality of the meals offered in the Food and Nutrition Units of companies participating in the Worker's Food Program, in the city of São Paulo . METHODS: This was a cross-sectional study of 72 companies participating in the program. Information regarding three consecutive days of meals served during lunch, supper and late supper were collected. The quality of the meals was assessed by the Meals Quality Index and its analysis was done in a stratified manner according to the company profile obtained through cluster analysis. RESULTS: The Meals Quality Index mean for the meals was 66.25%. Two groups of companies were obtained through cluster analysis. The companies in the first group consisted mostly of stores and micro- and small-sized companies, registered in the category of self-management and without the supervision of a dietician. They presented the worst meal quality (Index = 56.23). The companies in the second cluster consisted mostly of medium- and big-sized companies that outsourced meal production and counted with the supervision of a dietician. Their mean score on the Index was 82.95. CONCLUSION: The meals offered by the companies participating in the Worker's Food Program were not adequate according to the Meals Quality Index. The smaller companies in size and structure had worse meals when compared with the other companies, showing that companies with this profile should be the priority of interventions within the Worker's Food Program

Simulation-Based Optimization for the Scheduling of Elective Surgery Under Uncertainty And Downstream Capacity Constraints

The generation of an optimal schedule of elective surgery cases for a hospital surgery services unit is a well-known problem in the operations research field. The complexity of the problem is greatly compounded when uncertainties in the parameters are considered and is an issue that has been addressed in few works in the literature. Uncertainties appear in surgery durations and the availability of downstream resources such as surgical intensive care units (SICU), presenting large deviations from their expected value and impacting in the performance of the scheduling process. The technique presented here addresses the uncertainties in the optimal scheduling of a given set of elective surgery cases by means of simulated-based optimization. The main advantage of this approach over previous works is that detailed systems? simulations can be constructed without losing computational performance, thus improving the robustness of the scheduling solution.Fil: Durand, Guillermo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentin

A stiff non-linear ODE simulation of a batch/continuous plant using matlab/simulink

A sugarhouse is one stage in the production of beet sugar. The purpose of the sugarhouse is to crystallize and separate sugar from the thick juice obtained in previous stages. These crystallization and separation processes are carried out in batteries of batch units, while the upstream and downstream stages are continuous. The dynamics of such plant generate a highly non-linear model, and the sequencing of the batch and intra-batch operations makes the simulation a problem with heavy stiff characteristics. The simulation is an ODE problem and is carried out in a MATLAB/Simulink© environment. But the choice of the correct ODE solver depends on their performance to handle the model’s stiff and non-linear characteristics. This project studies each ODE solver present in the Simulink suite. The study will consider also how the solver parameters affect its capacity to solve this simulation problem. The final purposes of the sugarhouse simulation are: a) provide a test-bed where to apply proposed schedules for the batch units in order to obtain the optimal operation, and b) generate a training tool for operators and plant managers.Fil: Durand, Guillermo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Design of stable metabolic networks

In this work, we propose eigenvalue optimization combined with Lyapunov theory concepts to ensure stability of the Embden—Meyerhof–Parnas pathway, the pentosephosphate pathway, the phosphotransferase system and fermentation reactions of Escherichia coli. We address the design of a metabolic network for the maximization of different metabolite production rates. The first case study focuses on serine production, based on a model that consists of 18 differential equations corresponding to dynamic mass balances for extracellular glucose and intracellular metabolites, and thirty kinetic rate expressions. A second case study addresses the design problem to maximize ethanol production, based on a dynamic model that involves mass balancesfor 25 metabolites and 38 kinetic rate equations. The nonlinear optimization problem including stability constraints has been solved with reduced space Successive Quadratic Programming techniques. Numerical results provide useful insights on the stability properties of the studied kinetic models.Fil: Di Maggio, Jimena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Blanco, Anibal Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Diaz Ricci, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Díaz, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Comparación de diseños de ruteo para la recolección de envases vacíos de agroquímicos en el sudoeste bonaerense

De acuerdo a la Ley Nacional 24.051, los envases que almacenaron agroquímicos son residuos peligrosos, entendiendo como peligroso a “todo residuo que pueda causar daño directa o indirectamente a seres vivos o contaminar el suelo, el agua, la atmósfera o el ambiente en general”, calificándolos en particular como Y4: desechos resultantes de la producción, preparación y utilización de biocidas y productos fitosanitarios. Estos envases contaminados se transforman no solo en un residuo de difícil eliminación, sino también en un elemento de alta peligrosidad pero su material es económicamente valioso y técnicamente reciclable. Argentina adoptó la técnica del triple lavado por la Norma IRAM N° 12.069 basada en una normativa de la EPA de los años setenta. En principio, entonces, el plástico de los bidones podría reutilizarse pero primero debe completar un proceso de descontaminación siguiendo el protocolo de triple lavado, por parte de los aplicadores, y luego un procesamiento en plantas especializadas (que deben estar habilitadas como procesadores de residuos especiales) que implica el lavado y posterior tratamiento de los efluentes para eliminar los contaminantes. Una problemática aún no resuelta a nivel nacional, además del tipo de procesamiento que permite garantizar la trazabilidad del producto obtenido a partir de este proceso, es cómo llevar a cabo la logística para obtener la materia prima (residuo del acto de utilización de productos agroquímicos), minimizando así la presencia de un residuo contaminante en las áreas rurales y urbanas de la República Argentina. En el presente trabajo, se presenta una propuesta de un circuito que se denominará “abierto” para la recolección y acopio de envases vacíos, para su posterior procesamiento, la cual se propone como una alternativa para disponer de un modelo de sistema de gestión que pueda abastecer a una o más plantas de tratamiento de envases (a diseñar en base a tecnologías disponibles y/o a nuevas tecnologías actualmente en período de prueba). Luego, los resultados de dicha propuesta se compararán con los resultados obtenidos en otro trabajo que aborda la misma problemática a través de un diseño de recorrido diferente que se denominará “circuito cerrado”. Los resultados obtenidos podrían utilizarse para diseñar posteriormente una Experiencia Piloto de Gestión Ambiental Participativa de envases de agroquímicos en el SOB

Energy density in the diet of workers from São Paulo, Brazil, and associated socio-demographic factors*

Objective: This paper aims at analyzing the energy density (ED) of the diet of workers from the city of São Paulo, Southeastern Brazil, and the way this is associated with socio-demographic characteristics, as well as evaluating the relationship between ED and nutrient intake. Methods: A cross-sectional study evaluated the diet of 852 workers using the 24-hour dietary recall; one recall was applied to all individuals and a second one was applied to a sub-sample in order to adjust intrapersonal variability. The ED of the diet was calculated using three methods: inclusion of all solid foods and beverages, excluding water (ED 1); inclusion of all solid foods and beverages containing at least 5 kcal/100g (ED 2); and inclusion of all solid foods, excluding all beverages (ED 3). Linear regression was used to analyze the relationship between ED and socio-demographic variables and the relationship between ED and nutrients was evaluated using Pearson coefficient correlation. Results: Considering the workers' diet, the ED values observed were 1.18 kcal/g, 1.22 kcal/g and 1.73 kcal/g for the ED 1, ED 2, ED 3 methods, respectively. In the multiple regression models, only the age variable was maintained in the final model and showed an inverse association with all ED methods. ED 3 showed an increase in energy density for non-white individuals. Of all studied nutrients, protein was the only one that was not significantly correlated with ED 3 (p = 0.899). Conclusion: The young adults studied had a higher energy-density diet, representing a priority group for nutrition interventions. Regardless of the calculation method used, there is a correlation between ED and nutrients.Objetivo: Analisar a densidade energética (DE) da dieta de trabalhadores da cidade de São Paulo e sua associação com características sociodemográficas, bem como avaliar a relação entre DE e ingestão de nutrientes. Métodos: Estudo transversal que avaliou a dieta de 852 trabalhadores, por meio de recordatório de 24 horas, sendo um recordatório aplicado a todos os indivíduos e um segundo para subamostra, a fim de corrigir a variabilidade intrapessoal. A DE da dieta foi calculada por três métodos: inclusão de todos os alimentos sólidos e das bebidas, excluindo apenas água (DE 1); inclusão de todos os alimentos sólidos e bebidas calóricas que contêm, no mínimo, 5 kcal/100g (DE 2); inclusão de todos os alimentos sólidos e exclusão de todas as bebidas (DE 3). Para analisar a relação entre a DE e as variáveis sociodemográficas utilizou-se regressão linear, e a relação entre DE e nutrientes foi avaliada por meio do coeficiente de correlação de Pearson. Resultados: Para a dieta dos trabalhadores, os valores de DE observados foram 1,18 kcal/g, 1,22 kcal/g e 1,73 kcal/g, considerando-se os métodos DE 1, DE 2 e DE 3, respectivamente. Nos modelos múltiplos de regressão, apenas a variável idade apresentou associação negativa com todos os métodos de DE. Para a DE 3, houve incremento da DE para indivíduos não brancos. Dentre os nutrientes estudados, o único que não apresentou correlação significativa foi a proteína, para DE 3 (p = 0,899). Conclusão: Os adultos jovens tinham uma alimentação com maior DE, sendo um grupo prioriatário para intervenções nutricionais. Além disso, independente do método de cálculo, há correlação entre a DE e os nutrientes da dieta.Universidade de São Paulo Faculdade de Saude Publica Programa de Pos Graduacao em NutricaoUniversidade Federal de São Paulo (UNIFESP) Instituto de Saude e Sociedade Departamento de Saude, Clinica e InstituicoesUniversidade de São Paulo Faculdade de Saude Publica Departamento de NutricaoUNIFESP, Instituto de Saude e Sociedade Depto. de Saude, Clinica e InstituicoesSciEL