1,190 research outputs found
The structure of the infinite models in integer programming
The infinite models in integer programming can be described as the convex
hull of some points or as the intersection of halfspaces derived from valid
functions. In this paper we study the relationships between these two
descriptions. Our results have implications for corner polyhedra. One
consequence is that nonnegative, continuous valid functions suffice to describe
corner polyhedra (with or without rational data)
Efeito de variáveis de extrusão em propriedades fisicas de extrusados de farinha integral de trigo germinado (FITG).
[extruded Rice Flour As A Gluten Substitute In The Poduction Of Rice Bread].
Research regarding the production of gluten-free bread (GFB) is very important nutritionally, technically and economically speaking, both to celiac patients and to developing countries who import wheat. The main technological problem in the production of GFB is obtaining a gluten substitute that is both inexpensive and capable of retaining gas during bread fermentation and baking. The use of gelatinized starch as an alternative for gluten seems promising. In this project, rice bread was made using pregelatinized extruded rice flour as a gluten substitute. Pre-gelatinized rice flours (PRF) were manufactured in a single screw Brabender extruder, varying extrusion temperature (108-192 degrees C) and the moisture of the raw material (19.2 - 24.8%), and were used in a proportion of 10 g for every 100 g of raw rice flour, in the production of gluten-free bread. Results showed that rice flour extruded at a high temperature (180 degrees) and low moisture content (20%), rendered bread with the best technological characteristics, presenting crust and crumb color similar to those of conventional wheat bread, although with volume and texture not as satisfactory in the same comparison.56288-9
Duration Prediction Models for Construction Projects in Middle East
Construction industry is one of the most influential motivators of a national economy. The success of construction projects is indispensable to sustain a robust economy. Completion time is important for construction projects, nevertheless project multifaceted objectives, sophisticated nature, inherent uncertainties, and risks are success impediments and can cause time overrun. Stochastic models and simulation scheduling techniques are developed to predict the risk and uncertainty effects on construction projects’ duration. The objective of this research is to develop models that predict the activity durations based on actual data from similar projects. The study introduces comprehensive statistical regression models using historical data of about 84,000 activities in Egypt, Kuwait, and Saudi Arabia. The activities encompass engineering, procurement and construction (EPC) activities for most disciplines of construction projects. The regression models can be utilized to predict more reliably the activities’ duration
EFEITO DA UMIDADE E DA TEMPERATURA NO PROCESSAMENTO DE FARINHA DE BANANA VERDE (Musa acuminata, GRUPO AAA) POR EXTRUSÃO TERMOPLÁSTICA
Testou-se a utilização de farinha de banana da variedade
Nanicão no processo de extrusão termoplástico, visando
analisar as características dos produtos obtidos em função
das variáveis umidade e temperatura de extrusão. Os
experimentos variaram em torno dos pontos centrais de
umidade e temperatura de 20% e 150ºC, respectivamente,
observando-se o efeito conjugado dessas variáveis sobre
as características físicas e físico-químicas dos produtos
extrusados. O processo de extrusão propiciou grande
degradação do amido de banana e as amostras
apresentaram elevado grau de gelatinização em todas as
condições estudadas. O índice de solubilidade aumentou
com a elevação da temperatura e diminuição da umidade.
Verificou-se maior viscosidade de pasta a frio e a quente
com aumento da umidade da matéria-prima. As maiores
taxas de expansão foram obtidas com temperaturas mais
elevadas e umidades mais baixas. A energia mecânica
específica foi reduzida conforme o aumento da umidade e
da temperatura de extrusão. Confirmou-se a quebra da
molécula de amido sob as condições de extrusão pela
redução do conteúdo de amido das amostras
Mikrosfere ropinirol hidroklorida za polagano oslobađanje: Utjecaj procesnih parametara
An emulsion solvent evaporation method was employed to prepare microspheres of ropinirole hydrochloride, a highly water soluble drug, by using ethylcellulose and PEG with the help of 32 full factorial design. The microspheres were made by incorporating the drug in a polar organic solvent, which was emulsified using liquid paraffin as an external oil phase. Effects of various process parameters such as viscosity of the external phase, selection of the internal phase, surfactant selection and selection of stirring speed were studied. Microspheres were evaluated for product yield, encapsulation efficiency and particle size. Various drug/ethylcellulose ratios and PEG concentrations were assayed. In vitro dissolution profiles showed that ethylcellulose microspheres were able to control release of the drug for a period of 12 h.Mikrosfere ropinirol hidroklorida, ljekovite tvari vrlo dobro topljive u vodi, pripravljene su metodom isparavanja otapala, koristeći etilcelulozu i PEG te 32 potpuno faktorijalno dizajniranje. Mikrosfere su pripravljene na sljedeći način: otopina ljekovite tvari u polarnom organskom otapalu emulgirana je s tekućim parafinom kao vanjskom uljnom fazom. Ispitivan je utjecaj različitih procesnih parametara poput viskoznosti vanjske faze, vrste interne faze i površinski aktivne tvari te brzine miješanja. Za pripravljene mikrosfere određeno je iskorištenje, učinkovitost inkapsuliranja i veličina čestica. Isprobavani su različiti odnosi ljekovite tvari i etilceluloze te koncentracija PEG-a. In vitro pokusi su pokazali da je oslobađanje ljekovite tvari kontrolirano tijekom 12 h
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
Características tecnológicas de farinhas de arroz pré-gelatinizadas obtidas por extrusão termoplástica
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