13,445 research outputs found

    Trends and topics in IJPR from 1961 to 2017:a statistical history

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    This paper studies the history of the International Journal of Production Research (IJPR) by analysing the topics that have received the most attention in each of the journal’s publication years. Text mining exposed for scrutiny the most frequently mentioned and cited terms contained in the titles, abstracts and keywords of IJPR papers. Analyses suggest that the triad of scheduling/optimisation/simulation and supply-chain-related topics have been IJPR’s mainstays, but valuable opportunities remain for relevant topics that have not yet been concurrently and frequently studied. Results also show that terms related to sustainability and risk management topics have gained recent relevance. In addition, IJPR appears to complement its modelling technique focus with empirical methodological approaches to provide a well-balanced perspective, since the ‘case study’ term is common. Finally, a linear relationship is found between the number of papers that have covered certain topics and the number of citations those topics have received, highlighting which topics had fewer or more citations than expected, given the number of papers that covered those topics. IJPR stands as one of the most prestigious and established journals in its field and the results from this study indicate the evolving interests of the field for over half a century

    Serial production line performance under random variation:Dealing with the ‘Law of Variability’

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    Many Queueing Theory and Production Management studies have investigated specific effects of variability on the performance of serial lines since variability has a significant impact on performance. To date, there has been no single summary source of the most relevant research results concerned with variability, particularly as they relate to the need to better understand the ‘Law of Variability’. This paper fills this gap and provides readers the foundational knowledge needed to develop intuition and insights on the complexities of stochastic simple serial lines, and serves as a guide to better understand and manage the effects of variability and design factors related to improving serial production line performance, i.e. throughput, inter-departure time and flow time, under random variation

    Uso da terra no municipio de Aquidauana em 1990 - Pantanal.

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    Este trabalho tem como objetivo identificar as formas de uso da Terra no municipio de Aquidauana, localizado no sudeste do Pantanal, em Mato Grosso do Sul. Foram mapeadas as areas antropicas e identificadas e quantificadas as respectivas classes tematicas de uso. Utilizaram-se imagens de satelite Landsat 5-TM, em papel, na escala 1:250.000, na composicao colorida 3B, 4G e 5R para espacializacao das informacoes e um Sistema de Informacoes Geograficas para a quantificacao das areas. A area do municipio foi calculada em 1.485.526 ha, dos quais 76,8% esta inserida na planicie do Pantanal. Foram mapeadas as seguintes classes de uso: Area Natural (88,42%), Pastagem Cultivada (11,34%), Area Urbana (0,12%) e Area Agricola (0,12%). As terras do municipio sao predomi-nantemente utilizadas para pecuaria bovina de corte. Os maiores cultivos de pastagem estao localizados no planalto, onde predomina a Brachiaria decumbens. Ha tambem a presenca de coloniao (Panicum maximum), onde o solo e mais fertil. No Pantanal, em menor proporcao, predomina a Brachiaria humidicola. As areas agricolas estao localizadas nas aldeias indigenas da regiao, sendo utilizadas para culturas anuais e perenes.bitstream/item/37751/1/DOC17.pd

    Vine shoots pre-treatment strategies for improved hydrogen production and metabolites redistribution in Clostridium butyricum

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    This work deals with the use of vine shoots, a renewable, largely available, lacking of alternatives lignocellulosic material as a feedstock for hydrogen production. Physical pre-treatments by steam explosion (SE), chemical by organosolv (OS) and biological by laccase (LAC) were carried out in vine shoots to disrupt the cell fiber and increase the biomass hydrolysis and fermentation into hydrogen (H2). After SE, there was a slight decrease in cellulose and hemicellulose contents in biomass fibers, while a decrease in lignin content occurred after OS pretreatment. There were no quantifiable changes after laccase pre-treatment, however the enzyme-substrate oxidative reactions were favorable for hydrolysis and fermentation since an increase in soluble sugars and H2 production was observed with LAC vine shoots as substrate. 300.1 mL H2/L were obtained from raw material vine shoots, while 649.4, 399.8 and 749.7 mL H2/L were obtained from biomass pre-treated by SE, OS and LAC, respectively. Furthermore, the hydrolysis of pre-treated biomass by addition of cellulase was evaluated to improve H2 production. Higher amounts of H2 were obtained from hydrolyzed biomass in relation to nonhydrolyzed ones (154.2%, 602.0% and 167.1% more with SE, OS and LAC hydrolyzed, respectively). In all cases, the mixed acid pathway was carried out by Clostridium butyricum, since acetic and butyric acids were produced.MCIN/AEI/10.13039/501100011033/ FEDER, reference project PID2020-112594RB-C31. Junta de Andalucía, Postdoctoral researcher R-29/12/202

    Micro-costing analysis of guideline-based treatment by direct-acting agents: the real-life case of hepatitis C management in Brazil

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    Background Eradication of hepatitis C virus (HCV) using direct-acting agents (DAA) has been associated with a financial burden to health authorities worldwide. We aimed to evaluate the guideline-based treatment costs by DAAs from the perspective of the Brazilian Ministry of Health (BMoH). Methods The activity based costing method was used to estimate the cost for monitoring/treatment of genotype-1 (GT1) HCV patients by the following strategies: peg-interferon (PEG-IFN)/ribavirin (RBV) for 48 weeks, PEG-IFN/RBV plus boceprevir (BOC) or telaprevir (TEL) for 48 weeks, and sofosbuvir (SOF) plus daclastavir (DCV) or simeprevir (SIM) for 12 weeks. Costs were reported in United States Dollars without (US)andwithadjustmentforpurchasingpowerparity(PPP) and with adjustment for purchasing power parity (PPP). Drug costs were collected at the National Database of Health Prices and an overview of the literature was performed to assess effectiveness of SOF/DCV and SOF/SIM regimens in real-world cohorts. Results Treatment costs of GT1-HCV patients were PPP43,176.28(US 43,176.28 (US 24,020.16) for PEG-IFN/RBV, PPP71,196.03(US 71,196.03 (US 39,578.23) for PEG-IFN/RBV/BOC and PPP86,250.33(US 86,250.33 (US 47,946.92) for PEG-IFN/RBV/TEL. Treatment by all-oral interferon-free regimens were the less expensive approach: PPP19,761.72(US 19,761.72 (US 10,985.90) for SOF/DCV and PPP21,590.91(US 21,590.91 (US 12,002.75) for SOF/SIM. The overview reported HCV eradication in up to 98% for SOF/DCV and 96% for SOF/SIM. Conclusion Strategies with all oral interferon-free might lead to lower costs for management of GT1-HCV patients compared to IFN-based regimens in Brazil. This occurred mainly because of high discounts over international DAA prices due to negotiation between BMoH and pharmaceutical industries

    Diabetes y su impacto en el territorio periodontal

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    ResumenDiabetes y enfermedad periodontal corresponden probablemente al mejor ejemplo de cómo una enfermedad sistémica puede tener un efecto en el territorio periodontal. Si bien esta asociación ha sido extensamente estudiada, muchas de las asociaciones propuestas presentan contradicciones. En la presente revisión de la literatura se analizan los siguientes tópicos relevantes para la práctica clínica en periodoncia e implantología: i) Identificación de enfermedad periodontal severa y su capacidad para diagnosticar casos de diabetes; ii) Efectos de la diabetes sobre la enfermedad periodontal; iii) Efectos de la diabetes sobre la reparación periodontal y periimplantaria; iv) Efecto del tratamiento periodontal sobre el control metabólico de la diabetes.AbstractDiabetes and periodontal disease correspond to conditions that probably exemplify how a systemic disease may have a strong impact in the periodontium. Although this association has been studied for several years, many of these studies still show contradictory results. The present review analyses the following questions relevant for the clinician in the fields of periodontology: i) Value of the diagnosis of severe periodontitis and its capacity to identify previously un-diagnosed cases of diabetes; ii) Effects of diabetes on periodontal disease; iii) Effects of diabetes on periodontal and periimplant tissue repair and regeneration and; iv) Effect of periodontal therapy on the metabolic control of diabetes

    Nucleation kinetics of crystalline phases from a kaolinitic body used in the processing of red ceramics

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    The crystallization kinetics of red ceramic raw material from the western part of São Paulo State, Brazil, was examined by differential thermal analysis (DTA) and X-ray diffraction (XRD). The chemical composition of the clay sample was determined by X-ray fluorescence (XRF). Non-isothermal crystallization kinetic methods have been applied to the study of the mechanism of crystallization in this kaolinitic material. The exothermic peak shifted to higher temperatures (945 to 974 °C) with increasing heating rate (10 to 50 °C/min). The average activation energies determined by the Kissinger method (787 ± 85 kJ/mol) and the Ligero method (721 ± 32 kJ/mol) are in agreement. The Avrami constant n obtained by the Ligero method and the m parameter (Matusita method) values were between 1 and 1.5, which indicate a three-dimensional crystal growth with polyhedral morphology and surface nucleation as the dominant mechanism. X-ray diffraction data indicate that this activation energy is not associated with the crystallization of mullite. Scanning electron microscopy (SEM) images of fired (1000 and 1190 °C) samples show their densification during the sinterization process.The authors thank FUNDUNESP and FAPESP (2008/04368-4) for financial support of this work. We also are grateful to PROPE/UNESP/SANTANDER for Dr. Teixeira's post-doc scholarship in MadridPeer reviewe
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