Greedy randomized dispatching heuristics for the single machine scheduling problem with quadratic earliness and tardiness penalties

In this paper, we present greedy randomized dispatching heuristics for the single machine scheduling problem with quadratic earliness and tardiness costs, and no machine idle time. The several heuristic versions differ, on the one hand, on the strategies involved in the construction of the greedy randomized schedules. On the other hand, these versions also differ on whether they employ only a final improvement step, or perform a local search after each greedy randomized construction. The proposed heuristics were compared with existing procedures, as well as with optimum solutions for some instance sizes. The computational results show that the proposed procedures clearly outperform their underlying dispatching heuristic, and the best of these procedures provide results that are quite close to the optimum. The best of the proposed algorithms is the new recommended heuristic for large instances, as well as a suitable alternative to the best existing procedure for the larger of the middle size instances.scheduling, single machine, early/tardy, quadratic penalties, greedy randomized dispatching rules

Improving order-picking operations with precedence constraints through efficient storage location assignment: evidence from a retail company

This paper is inspired by a manual picking retail company where shape and weight constraints affect the order-picking process. We proposed an alternative clustering similarity index that considers the similarity, the weight and the shape of products. This similarity index was further incorporated in a storage allocation heuristic procedure to set the location of the products. We test the procedure in a retail company that supplies over 191 stores, in Northern Portugal. When comparing the strategy currently used in the company with this procedure, we found out that our approach enabled a reduction of up to 40% on the picking distance; a percentage of improvement that is 32% higher than the one achieved by applying the Jaccard index, a similarity index commonly used in the literature. This allows warehouses to save time and work faster.info:eu-repo/semantics/publishedVersio

Mineral content in French type bread with sodium replacement using fluorescence spectrometry X-rays by energy dispersive

The present study aimed to determine the mineral composition of the French type bread with partial replacement of sodium chloride by potassium chloride using the technique of X-ray fluorescence energy dispersive. The excitation energy used was 50 keV and detector operation at -176°C. The detected variations were from 10.16 to 613.69 mg 100 g-1 for sodium and from 211.58 to 958.96 mg 100 g-1 for potassium. The concentrations of iron, magnesium, phosphorus and calcium ranged from 10.62 to 21.45, 16.59 to 30.78, 92.53 to 125.77 and from 16.54 to 100.88 mg 100 g-1, respectively. The use of this simple technique proved to be reliable on detecting the variations imposed on the French type bread formulation. The results of this study indicate that, at the levels studied, the addition of potassium chloride assisted in getting French type bread with lower levels of sodium and proved the technological feasibility of producing French type bread with 43% salt reduction (1.0% in the commercial formulation) with 0.5% potassium chloride, which provide bread with the amount of sodium proposed to meet the set limits (174.09 mg.50 g-1), related to the salt standard formulation of 1.88% (306.5 mg.50 g-1).Key words: French bread, replacement, sodium chloride, potassium chloride, food analysis, minerals, energy dispersive

TRANSIENT HEAT TRANSFER ANALYSIS UP TO DRYOUT IN 3D FUEL RODS UNDER UNIDEAL CONDITIONS THROUGH THE DEVELOPMENT OF A COMPUTER CODE

In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric.In this paper we analyze a conjugated transient heat transfer problem consisting of a nuclear reactor’s fuel rod and its intrinsic coolant channel. Our analysis is made possible through a computer code being developed at the Instituto de Engenharia Nuclear (IEN/CNEN). This code is meant to study the temperature behavior in fuel rods which exhibit deviation from their ideal conditions, that is, rods in which the cladding is deformed or the fuel is dislocated. It is also designed to avoid the use of the computationally expensive Navier-Stokes equations. For these reasons, its physical model has as basis a three-dimensional fuel rod coupled to a one-dimensional coolant channel, which are discretized using the finite element method. Intending to study accidental conditions in which the coolant (light water) transcends its saturation temperature, turning into vapor, a homogeneous mixture is used to represent the two-phase flow, and so the coolant channel’s energy equation is described using enthalpy. Owing to the fact that temperature and enthalpy are used in the physical model, it became impractical to generate a fully coupled method for solving the pertinent equations. Thus, the conjugated heat transfer problem is solved in a segregated manner through the implementation of an iterative method. Finally, as study cases for this paper we present analyses concerning the behavior of the hottest fuel rod in a Pressurized Water Reactor during a shutdown wherein the residual heat removal system is lost (loss of the reactor’s coolant pumps). These studies contemplate cases in which the fuel rod’s geometry is ideal or curved. Analyses are also performed for two circumstances of positioning of the fuel inside the rod: concentric and eccentric

Cellulolytic ability of Penicillium strains isolated from soil of the Brazilian Atlantic forest

Penicillium spp. are capable of degrading plant wastes by producing large amounts of enzymes such as cellulases. These form a complex capable of acting on cellulosic materials and producing sugars with industrial interest (e.g., ethanol production). Cellulases are also used for (a) pulp and paper industry (b) in the textile industry. The aim of this study was to evaluate the cellulolytic capability of 17 strains of Penicillium isolated from soil of the Brazilian Atlantic Forest and conserved under mineral oil at the URM Culture Collection. All strains were re-grown from mineral oil and re-identifiied. Each strain was grown in synthetic medium with carboxymethylcellulose as the carbon source and incubated for 5 days at 28°C. Strains were subjected to heat shock for 16h at 50°C. Thereafter, onto each colony was added 5 ml of Congo red stain solution in Tris-HCl. After 30 min this solution was removed and the cultures were washed and submerged under 0.1 M NaCl aqueous solution for 5 min. Finally, an enzymatic index was calculated from the ratio of the diameter of the halo around each colony to the diameter of the colony. All of the 17 strains tested showed a halo of cellulose degradation, indicating enzyme production. The enzymatic ratios varied between 0.2 (Penicillium brevicompactum URM5994) and 3.3 (Penicillium glabrum URM6009). Thus, Penicillium glabrum URM6009 is evaluated as a high producer of cellulase. It was selected for quantitative production of this enzyme and additional studies are taking place in order to verify potential industrial application for clarification of fruit juices

The prevalence of and variables associated with smoking in children and adolescents

OBJECTIVE: To identify the prevalence of smoking and the presence of variables associated with the habit in children and adolescents of both sexes, aged 7 to 17 years, resident in the city of Maceió. METHODS: A cross-sectional epidemiological study of the student population of the both private and public education systems at elementary and high school level. Sample size was calculated based on the minimum predicted prevalence of a large number of variables, including smoking itself. Cluster sampling was employed. A questionnaire on smoking habits was completed during individual interviews with each student. Children who admitted having smoked on 1 or more day during the previous 30 were defined as current smokers. The variables analyzed were related to: the students (age, sex, previous experimentation with cigarettes and paid employment), their educational status (public/private school, daytime/evening lessons, grade and repeated years) and their families (economic status, smoking parents and separated parents). RESULTS: A total of 1,253 students were analyzed (547 were male, mean age was 12.4 2.9 years). Observed smoking prevalence was 2.4%. Multivariate statistical analysis demonstrated significant associations between smoking and: increased age (odds ratio: 1.31); previous experimentation with cigarettes (odds ratio: 33.96); studying during the evening (odds ratio: 5.43). It was observed that 286 students (22.8%) admitted having experimented with cigarettes (9% from 7 to 9 years; 21% from 10 to 14 years; 36% from 15 to 17 years). CONCLUSIONS: The prevalence of smoking among children and adolescents in the Maceió educational system is 2.4%, being most common among students aged 15 to 17 years, studying in the evening. Students who had experimented with cigarettes exhibited a 34 times greater chance of becoming smokers.OBJETIVO: Identificar a prevalência do hábito de fumar e a ocorrência de variáveis associadas ao hábito em crianças e adolescentes de 7 a 17 anos, de ambos os sexos e provenientes da cidade de Maceió. MÉTODOS: Estudo epidemiológico transversal, baseado na população de alunos da rede de ensino público e privada, níveis fundamental e médio. Cálculo da amostra baseado na menor prevalência esperada de inúmeras variáveis, incluindo tabagismo. Amostragem por conglomerados. Questionário sobre o hábito de fumar; entrevista individual com cada estudante. Considerado fumante atual aquele que admitiu ter fumado em 1 ou mais dias nos últimos 30 dias. Variáveis analisadas: relacionadas ao estudante (idade, sexo, experimentação prévia de cigarros e trabalho remunerado), à sua condição na escola (pública/privada, turno, nível e repetência) e à família (classificação econômica, pais fumantes e pais separados). RESULTADOS: Foram avaliados 1.253 estudantes (547 do sexo masculino, média de idade 12,4±2,9 anos). Identificou-se uma prevalência de tabagismo de 2,4%. A análise estatística multivariada demonstrou associação significante do hábito de fumar com: maior idade (odds ratio de 1,31); experimentação prévia de cigarros (odds ratio de 33,96); estudar no período noturno (odds ratio de 5,43). Observou-se que 286 estudantes (22,8%) admitiram haver experimentado cigarros (9% de 7 a 9 anos; 21% de 10 a 14 anos; 36% de 15 a 17 anos). CONCLUSÕES: A prevalência de tabagismo em crianças e adolescentes da rede de ensino da cidade de Maceió é de 2,4%, sendo mais freqüente em estudantes de 15 a 17 anos, do curso noturno. Estudantes que experimentaram cigarros apresentam 34 vezes mais chances de se tornarem fumantes.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de Alagoas Faculdade de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de AlagoasUNIFESP, EPMSciEL

Modulation of bone marrow mesenchymal stem cell secretome by ECM-like hydrogels

It has been demonstrated that bone marrow mesenchymal stem cell (BM-MSCs) transplantation has beneficial effects on several central nervous system (CNS) debilitating conditions. Growing evidence indicate that trophic factors secreted by these cells are the key mechanism by which they are acting. These cells are frequently used in combination with 3D artificial matrices, for instance hydrogels, in tissue engineering-based approaches. However, so far, no study has been reported on the influence of such matrices, namely the presence or absence of extracellular matrix motifs, on BM-MSCs secretome and its effects in neuronal cell populations. In this sense, we herein studied the impact of a hydrogel, gellan gum, on the behavior and secretome of BM-MSCs, both in its commercial available form (commonly used in tissue engineering) and in a fibronectin peptide-modified form. The results showed that in the presence of a peptide in the gellan gum hydrogel, BM-MSCs presented higher proliferation and metabolic activity than in the regular hydrogel. Moreover, the typical spindle shape morphology of BM-MSCs was only observed in the modified hydrogel. The effects of the secretome of BM-MSCs were also affected by the chemical nature of the extracellular matrix. BM-MSCs cultured in the modified hydrogel were able to secrete factors that induced higher metabolic viabilities and neuronal cell densities, when compared to those of the unmodified hydrogel. Thus adding a peptide sequence to the gellan gum had a significant effect on the morphology, activity, proliferation and secretome of BM-MSCs. These results highlight the importance of mimicking the extracellular matrix when BM-MSCs are cultured in hydrogels for CNS applications.We would like to acknowledge the funds attributed by the Portuguese Foundation for Science and Technology (FCT) (Grant No PTDC/SAU-BMA/114059/2009; pre-doctoral fellowships to N.A. Silva, SFRH/BD/40684/2007; Ciencia 2007 Program to A.J. Salgado; PEst-C/SAU/LA0001/2013-2014 and RNEM-REDE/1506/REM/2005). This work was partially funded by EU-FP7-Health-2011-Collaborative Project 278612, Biohybrid Templates for Peripheral Nerve Regeneration, and co-funded by Programa Operacional Regional do Norte (ON.2 - O Novo Norte), ao abrigo do Quadro de Referencia Estrategico Nacional (QREN), atraves do Fundo Europeu de Desenvolvimento Regional (FEDER)