WorldWideScience

Sample records for hydrocarbon supply model

  1. Supply chain reliability modelling

    Directory of Open Access Journals (Sweden)

    Eugen Zaitsev

    2012-03-01

    Full Text Available Background: Today it is virtually impossible to operate alone on the international level in the logistics business. This promotes the establishment and development of new integrated business entities - logistic operators. However, such cooperation within a supply chain creates also many problems related to the supply chain reliability as well as the optimization of the supplies planning. The aim of this paper was to develop and formulate the mathematical model and algorithms to find the optimum plan of supplies by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Methods: The mathematical model and algorithms to find the optimum plan of supplies were developed and formulated by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Results and conclusions: The problem of ensuring failure-free performance of goods supply channel analyzed in the paper is characteristic of distributed network systems that make active use of business process outsourcing technologies. The complex planning problem occurring in such systems that requires taking into account the consumer's requirements for failure-free performance in terms of supply volumes and correctness can be reduced to a relatively simple linear programming problem through logical analysis of the structures. The sequence of the operations, which should be taken into account during the process of the supply planning with the supplier's functional reliability, was presented.

  2. Statistical evaluation of variables affecting occurrence of hydrocarbons in aquifers used for public supply, California

    Science.gov (United States)

    Landon, Matthew K.; Burton, Carmen A.; Davis, Tracy A.; Belitz, Kenneth; Johnson, Tyler D.

    2014-01-01

    The variables affecting the occurrence of hydrocarbons in aquifers used for public supply in California were assessed based on statistical evaluation of three large statewide datasets; gasoline oxygenates also were analyzed for comparison with hydrocarbons. Benzene is the most frequently detected (1.7%) compound among 17 hydrocarbons analyzed at generally low concentrations (median detected concentration 0.024 μg/l) in groundwater used for public supply in California; methyl tert-butyl ether (MTBE) is the most frequently detected (5.8%) compound among seven oxygenates analyzed (median detected concentration 0.1 μg/l). At aquifer depths used for public supply, hydrocarbons and MTBE rarely co-occur and are generally related to different variables; in shallower groundwater, co-occurrence is more frequent and there are similar relations to the density or proximity of potential sources. Benzene concentrations are most strongly correlated with reducing conditions, regardless of groundwater age and depth. Multiple lines of evidence indicate that benzene and other hydrocarbons detected in old, deep, and/or brackish groundwater result from geogenic sources of oil and gas. However, in recently recharged (since ~1950), generally shallower groundwater, higher concentrations and detection frequencies of benzene and hydrocarbons were associated with a greater proportion of commercial land use surrounding the well, likely reflecting effects of anthropogenic sources, particularly in combination with reducing conditions.

  3. MODELING SUPPLY CHAIN PERFORMANCE VARIABLES

    Directory of Open Access Journals (Sweden)

    Ashish Agarwal

    2005-01-01

    Full Text Available In order to understand the dynamic behavior of the variables that can play a major role in the performance improvement in a supply chain, a System Dynamics-based model is proposed. The model provides an effective framework for analyzing different variables affecting supply chain performance. Among different variables, a causal relationship among different variables has been identified. Variables emanating from performance measures such as gaps in customer satisfaction, cost minimization, lead-time reduction, service level improvement and quality improvement have been identified as goal-seeking loops. The proposed System Dynamics-based model analyzes the affect of dynamic behavior of variables for a period of 10 years on performance of case supply chain in auto business.

  4. Reseach of Supply Chain Modeling Technology

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The supply chain modeling technology is research. Firstly, the concept of supply chain and supply chain management is introduced. Secondly, enterprise-modeling methods, such as CIM-OSA, GIM-GRAI, PERA and ARIS, are analyzed and compared. The supply chain modeling technology is studied. Then the ARIS-based supply chain modeling method is proposed and the supply chain operation reference model is set up. Finally, the applications of ARIS-based supply chain modeling method in Shanghai Turbine Generator Co. Ltd. (STGC) is described in detail.

  5. Bioremediation of marine sediments contaminated by hydrocarbons: experimental analysis and kinetic modeling.

    Science.gov (United States)

    Beolchini, Francesca; Rocchetti, Laura; Regoli, Francesco; Dell'Anno, Antonio

    2010-10-15

    This work deals with bioremediation experiments on harbor sediments contaminated by aliphatic and polycyclic aromatic hydrocarbons (PAHs), investigating the effects of a continuous supply of inorganic nutrients and sand amendments on the kinetics of microbial growth and hydrocarbon degradation. Inorganic nutrients stimulated microbial growth and enhanced the biodegradation of low and high molecular weight hydrocarbons, whereas sand amendment increased only the removal of high molecular weight compounds. The simultaneous addition of inorganic nutrients and sand provided the highest biodegradation (>70% for aliphatic hydrocarbons and 40% for PAHs). A semi-empirical kinetic model was successfully fitted to experimental temporal changes of hydrocarbon residual concentrations and microbial abundances. The estimated values for parameters allowed to calculate a doubling time of 2.9 d and a yield coefficient biomass/hydrocarbons 0.39 g C biomass g-1C hydrocarbons, for the treatment with the highest hydrocarbon biodegradation yield. A comparison between the organic carbon demand and temporal profiles of hydrocarbons residual concentration allowed also to calculate the relative contribution of contaminants to carbon supply, in the range 5-32%. This suggests that C availability in the sediments, influencing prokaryotic metabolism, may have cascade effects on biodegradation rates of hydrocarbons. Even if these findings do not represent a general rule and site-specific studies are needed, the approach used here can be a relevant support tool when designing bioremediation strategies on site.

  6. Effects of oxygen supply on the biodegradation rate in oil hydrocarbons contaminated soil

    Science.gov (United States)

    Zawierucha, I.; Malina, G.

    2011-04-01

    Respirometry studies using the 10-chamber Micro-Oxymax respirometer (Columbus, Ohio) were conducted to determine the effect of biostimulation (by diverse ways of O2 supply) on enhancing biodegradation in soils contaminated with oil hydrocarbons. Soil was collected from a former military airport in Kluczewo, Poland. Oxygen was supplied by means of aerated water, aqueous solutions of H2O2 and KMnO4. The biodegradation was evaluated on the basis of O2 uptake and CO2 production. The O2 consumption and CO2 production rates during hydrocarbons biodegradation were estimated from the slopes of cumulative curve linear regressions. The pertinent intrinsic and enhanced biodegradation rates were calculated on the basis of mass balance equation and O2 uptake and CO2 production rates. The biodegradation rates of 5-7 times higher as compared to a control were observed when the aqueous solution of KMnO4 in concentration of 20 g L-1 was applied. Permanganate is known to readily oxidize alkene carbon - carbon double bonds; so it can be successfully applied in remediation technology for soils contaminated with oil hydrocarbons. While hydrocarbons are not completely mineralized by permanganate oxidation reactions, their structure is altered by polar functional groups providing vast improvements in aqueous solubility and availability for biodegradation. The 3% aqueous solution of H2O2 caused significant improvement of the biodegradation rates as compared to a control (on average about 260%). Aerobic biodegradation of hydrocarbons can benefit from the presence of oxygen released during H2O2 decomposition. Adding of aerated water resulted in an increase of biodegradation rates (about 114 - 229%) as compared to a control. The aerated water can both be the source of oxygen for microorganisms and determine the transport of substrate to bacteria cells.

  7. Water supply and demand in an energy supply model

    Energy Technology Data Exchange (ETDEWEB)

    Abbey, D; Loose, V

    1980-12-01

    This report describes a tool for water and energy-related policy analysis, the development of a water supply and demand sector in a linear programming model of energy supply in the United States. The model allows adjustments in the input mix and plant siting in response to water scarcity. Thus, on the demand side energy conversion facilities can substitute more costly dry cooling systems for conventional evaporative systems. On the supply side groundwater and water purchased from irrigators are available as more costly alternatives to unappropriated surface water. Water supply data is developed for 30 regions in 10 Western states. Preliminary results for a 1990 energy demand scenario suggest that, at this level of spatial analysis, water availability plays a minor role in plant siting. Future policy applications of the modeling system are discussed including the evaluation of alternative patterns of synthetic fuels development.

  8. Supply chain strategies, issues and models

    CERN Document Server

    Ramanathan, Ramakrishnan

    2014-01-01

    In the 21st century, supply chain operations and relationships among supply chain partners have become highly challenging, necessitating new approaches, e.g., the development of new models. Supply Chain Strategies, Issues and Models discusses supply chain issues and models with examples from actual industrial cases. Expert authors with a wide spectrum of knowledge working in various areas of supply chain management from various geographical locations offer refreshing, novel and insightful ideas and address possible solutions using established theories and models. Supply Chain Strategies, Issues and Models features studies that have used mathematical modeling, statistical analyses and also descriptive qualitative studies. The chapters cover many relevant themes related to supply chains and logistics including supply chain complexity, information sharing, quality (six sigma), electronic Kanbans, inventory models, scheduling, purchasing and contracts. To facilitate easy reading, the chapters that deal with suppl...

  9. Modeling Continuous IED Supply Chains

    Science.gov (United States)

    2014-03-27

    criminals, pirates, drug traffickers and terrorists. Moreover, JIEDDO has pointed out the spread of IED use to places such as Thailand and Norway. U.S... human networks that place IEDs. Dekker categorizes two main human aspects of IED placement. The first is motivation which 8 affects the number of...methods provided in this thesis and apply them to combat other threats. For example, drug trafficking supply chains. IED and drug trafficking supply

  10. Responsive supply chain: modeling and simulation

    Directory of Open Access Journals (Sweden)

    Amit Kumar Sinha

    2015-06-01

    Full Text Available Unexpected occurrence like natural calamity, abruptly change in customer demands, upgradation of technologies, necessity of compatible suppliers etc. is the most challenging issues even for efficient global supply chain management. Therefore, modeling of responsive supply chain is an emerging technology for sustaining any firm/industry in future competitive environment. In this paper, an attempt has been made to not only analyze the performance of efficient supply chain management but also how to improve the performance of existing supply chain with the objective of developing a modeling of responsive supply chain management. The complexity of the model is also highlighted with the help of numerical example. This paper also explores the possibility to mathematical modeling of the responsive supply chain which will be an emerging topic for researchers and practitioners. The modeling of responsive supply chain can be employed as a competitive strategy for e-commerce, green supply chain, and compatible supplier selection problem. The another salient feature of this paper is that a distinct comparative literature review of the lean, agile, efficient, and responsive supply chain management has been presented.

  11. The fishing industry - toward supply chain modelling

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Nielsen, Jette; Larsen, Erling P.

    Mathematical models for simulating and optimizing supply chain aspects such as distribution planning and optimal use of raw materials are widely used. However, modelling based on a holistic chain view is less studied, and food-related aspects such as quality and shelf life issues enforce additional...... requirements onto the chains. In this paper, we consider the supply chain structure of the Danish fishing industry and illustrate the potential of using mathematical models to identify quality and value-adding activities. This is a first step toward innovative supply chain modelling aimed to identify benefits...... for actors along chains in the fishing industry....

  12. A Capacity Supply Model for Virtualized Servers

    Directory of Open Access Journals (Sweden)

    Alexander PINNOW

    2009-01-01

    Full Text Available This paper deals with determining the capacity supply for virtualized servers. First, a server is modeled as a queue based on a Markov chain. Then, the effect of server virtualization on the capacity supply will be analyzed with the distribution function of the server load.

  13. Simplified Modeling of Oxidation of Hydrocarbons

    Science.gov (United States)

    Bellan, Josette; Harstad, Kenneth

    2008-01-01

    A method of simplified computational modeling of oxidation of hydrocarbons is undergoing development. This is one of several developments needed to enable accurate computational simulation of turbulent, chemically reacting flows. At present, accurate computational simulation of such flows is difficult or impossible in most cases because (1) the numbers of grid points needed for adequate spatial resolution of turbulent flows in realistically complex geometries are beyond the capabilities of typical supercomputers now in use and (2) the combustion of typical hydrocarbons proceeds through decomposition into hundreds of molecular species interacting through thousands of reactions. Hence, the combination of detailed reaction- rate models with the fundamental flow equations yields flow models that are computationally prohibitive. Hence, further, a reduction of at least an order of magnitude in the dimension of reaction kinetics is one of the prerequisites for feasibility of computational simulation of turbulent, chemically reacting flows. In the present method of simplified modeling, all molecular species involved in the oxidation of hydrocarbons are classified as either light or heavy; heavy molecules are those having 3 or more carbon atoms. The light molecules are not subject to meaningful decomposition, and the heavy molecules are considered to decompose into only 13 specified constituent radicals, a few of which are listed in the table. One constructs a reduced-order model, suitable for use in estimating the release of heat and the evolution of temperature in combustion, from a base comprising the 13 constituent radicals plus a total of 26 other species that include the light molecules and related light free radicals. Then rather than following all possible species through their reaction coordinates, one follows only the reduced set of reaction coordinates of the base. The behavior of the base was examined in test computational simulations of the combustion of

  14. MODELING SUPPLY CHAIN WITH SIMULATION

    OpenAIRE

    János Benkõ

    2010-01-01

    Supply Chain Management faces a lot of challenging issues involving difficult decisions which can be company-oriented and customer-oriented issues. In this study we deal with customeroriented issues. For example, a customer’s demand may not be fully satisfied from stock on hand and the shortage may be backordered or the sale may be lost. Either way, it is desirable to balance the holding cost which depends on the magnitude of inventory against the cost of not fully satisfying customer demand....

  15. Modelling green and lean supply chains

    DEFF Research Database (Denmark)

    Govindan, Kannan; Carvalho, Helena; Azevedo, Susana G.

    2017-01-01

    This manuscript proposes a model to support decision making and to help managers identify the best set of green and lean supply chain management practices to improve their eco-efficiency. To attain this objective, a mathematical model based on eco-efficiency concepts is suggested to overcome...... the trade-offs between lean and green practices. To illustrate the model application, a case study from an automotive supply chain is presented. Some management practices that are instituted for green or lean benefits have opposite effects on the environmental and economic performance of companies. One...... of the main findings of our study is that not all companies belonging to the same supply chain can be absolutely lean or green. There should be compromises in the individual companies’ behaviour so the environmental and economic constraints of the supply chain are both satisfied. The proposed model represents...

  16. The fish industry - toward supply chain modelling

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Nielsen, Jette; Larsen, Erling

    2010-01-01

    Mathematical models for simulating and optimizing aspects of supply chains such as distribution, planning, and optimal handling of raw materials are widely used. However, modeling based on a holistic chain view including several or all supply chain agents is less studied, and food-related aspects...... such as quality and shelf-life issues enforce additional requirements onto the chains. In this article, we consider the supply chain structure of the fish industry. We discuss and illustrate the potential of using mathematical models to identify quality and value-adding activities. The article provides a first...... step toward innovative supply chain modeling aimed to identify benefits for all agents along chains in the fish industry....

  17. Fossil fuels supplies modeling and research

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, P.N.

    1996-06-01

    The fossil fuel supplies modeling and research effort focuses on models for US Strategic Petroleum Reserve (SPR) planning and management. Topics covered included new SPR oil valuation models, updating models for SPR risk analysis, and fill-draw planning. Another task in this program area is the development of advanced computational tools for three-dimensional seismic analysis.

  18. Quantitative models for sustainable supply chain management

    DEFF Research Database (Denmark)

    Brandenburg, M.; Govindan, Kannan; Sarkis, J.

    2014-01-01

    Sustainability, the consideration of environmental factors and social aspects, in supply chain management (SCM) has become a highly relevant topic for researchers and practitioners. The application of operations research methods and related models, i.e. formal modeling, for closed-loop SCM...... and reverse logistics has been effectively reviewed in previously published research. This situation is in contrast to the understanding and review of mathematical models that focus on environmental or social factors in forward supply chains (SC), which has seen less investigation. To evaluate developments...

  19. Model feedstock supply processing plants

    Directory of Open Access Journals (Sweden)

    V. M. Bautin

    2013-01-01

    Full Text Available The model of raw providing the processing enterprises entering into vertically integrated structure on production and processing of dairy raw materials, differing by an orientation on achievement of cumulative effect by the integrated structure acting as criterion function which maximizing is reached by optimization of capacities, volumes of deliveries of raw materials and its qualitative characteristics, costs of industrial processing of raw materials and demand for dairy production is developed.

  20. Teaching Aggregate Demand and Supply Models

    Science.gov (United States)

    Wells, Graeme

    2010-01-01

    The author analyzes the inflation-targeting model that underlies recent textbook expositions of the aggregate demand-aggregate supply approach used in introductory courses in macroeconomics. He shows how numerical simulations of a model with inflation inertia can be used as a tool to help students understand adjustments in response to demand and…

  1. Teaching Aggregate Demand and Supply Models

    Science.gov (United States)

    Wells, Graeme

    2010-01-01

    The author analyzes the inflation-targeting model that underlies recent textbook expositions of the aggregate demand-aggregate supply approach used in introductory courses in macroeconomics. He shows how numerical simulations of a model with inflation inertia can be used as a tool to help students understand adjustments in response to demand and…

  2. Security Modeling on the Supply Chain Networks

    Directory of Open Access Journals (Sweden)

    Marn-Ling Shing

    2007-10-01

    Full Text Available In order to keep the price down, a purchaser sends out the request for quotation to a group of suppliers in a supply chain network. The purchaser will then choose a supplier with the best combination of price and quality. A potential supplier will try to collect the related information about other suppliers so he/she can offer the best bid to the purchaser. Therefore, confidentiality becomes an important consideration for the design of a supply chain network. Chen et al. have proposed the application of the Bell-LaPadula model in the design of a secured supply chain network. In the Bell-LaPadula model, a subject can be in one of different security clearances and an object can be in one of various security classifications. All the possible combinations of (Security Clearance, Classification pair in the Bell-LaPadula model can be thought as different states in the Markov Chain model. This paper extends the work done by Chen et al., provides more details on the Markov Chain model and illustrates how to use it to monitor the security state transition in the supply chain network.

  3. Modeling for Green Supply Chain Evaluation

    Directory of Open Access Journals (Sweden)

    Elham Falatoonitoosi

    2013-01-01

    Full Text Available Green supply chain management (GSCM has become a practical approach to develop environmental performance. Under strict regulations and stakeholder pressures, enterprises need to enhance and improve GSCM practices, which are influenced by both traditional and green factors. This study developed a causal evaluation model to guide selection of qualified suppliers by prioritizing various criteria and mapping causal relationships to find effective criteria to improve green supply chain. The aim of the case study was to model and examine the influential and important main GSCM practices, namely, green logistics, organizational performance, green organizational activities, environmental protection, and green supplier evaluation. In the case study, decision-making trial and evaluation laboratory technique is applied to test the developed model. The result of the case study shows only “green supplier evaluation” and “green organizational activities” criteria of the model are in the cause group and the other criteria are in the effect group.

  4. Supply Chain Sustainability Analysis of Fast Pyrolysis and Hydrotreating Bio-Oil to Produce Hydrocarbon Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Adom, Felix K.; Cai, Hao; Dunn, Jennifer B.; Hartley, Damon; Searcy, Erin; Tan, Eric; Jones, Sue; Snowden-Swan, Lesley

    2016-03-31

    This report describes the supply chain sustainability analysis (SCSA) of renewable gasoline and diesel produced via fast pyrolysis of a blended woody feedstock. The metrics considered in this analysis include supply chain greenhouse gas (GHG) emissions and water consumption.

  5. Integrating process and ontology to support supply chain modelling

    OpenAIRE

    2011-01-01

    Abstract Many researchers have recognized a lack of common framework to support supply chain modelling and analysis and proposed their solutions accordingly. Majority of the approaches proposed are more concerned with building an object model of a supply chain than identifying processes which realistically describe a supply chain. Though object models provide means or building blocks necessary to model and analyse different elements of a supply chain, an absence of supply chain pro...

  6. Thermodynamic study of characteristics of the converter with separated supply of hydrocarbon fuel for thermo-oxidative and steam reforming

    Science.gov (United States)

    Bassina, I. A.; Malkov, Yu. P.; Molchanov, O. N.; Stepanov, S. G.; Troshchinenko, G. A.; Zasypkin, I. M.

    2014-04-01

    Thermodynamic studies of the converter characteristics were performed to produce hydrogen-containing syngas from hydrocarbon fuel (kerosene) with its separated supply for thermo-oxidative and steam reforming. It is demonstrated that the optimal conditions of the converter performance correlate with the oxidant ratio of α > 0.5 at the heattransfer wall temperature of 1200 K. Hydrogen content in the final syngas reaches 60 % by volume, free carbon (soot) deposition in reforming products is excluded, and there is no need to apply walls water cooling in the converter.

  7. Neutron generator power supply modeling in EMMA

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, A.C.; Farnsworth, A.V.; Montgomery, S.T.; Peery, J.S; Merewether, K.O.

    1996-12-01

    Sandia National Laboratories has prime responsibility for neutron generator design and manufacturing, and is committed to developing predictive tools for modeling neutron generator performance. An important aspect of understanding component performance is explosively driven ferroelectric power supply modeling. EMMA (ElectroMechanical Modeling in ALEGRA) is a three dimensional compile time version of Sandia`s ALEGRA code. The code is built on top of the general ALEGRA framework for parallel shock-physics computations but also includes additional capability for modeling the electric potential field in dielectrics. The overall package includes shock propagation due to explosive detonation, depoling of ferroelectric ceramics, electric field calculation and coupling with a general lumped element circuit equation system. The AZTEC parallel iterative solver is used to solve for the electric potential. The DASPK differential algebraic equation package is used to solve the circuit equation system. Sample calculations are described.

  8. A preliminary evaluation model for reservoir hydrocarbon-generating potential established based on dissolved hydrocarbons in oilfield water

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A large number of oilfield water samples were analyzed in this work. Research on the relationship between the concentrations and distribution of dissolved hydrocarbons sug gested that the contents and composition of dissolved hydrocarbons varied with the hydrocar bon-generating potential of reservoirs. The concentrations of dissolved hydrocarbons were low in dry layers, water layers and gas-water layers, but high in gas reservoirs and oil reservoirs, especially in gas reservoirs with condensed oil. Series of carbon-number alkanes were usually absent in oilfield water from dry layers, water layers and gas-water layers but abundant in oil field water from oil-water reservoirs, gas reservoirs and oil reservoirs, whose carbon numbers varied most widely in oil reservoirs and least in gas reservoirs. A preliminary evaluation model for reservoir hydrocarbon-generating potential was established based on the characteristics of dissolved hydrocarbons in oilfield water to assist hydrocarbon exploration.

  9. PROSPECTIVE MODELLING OF OIL SUPPLY IN TUNISIA

    Directory of Open Access Journals (Sweden)

    Thameur Necibi

    2014-04-01

    Full Text Available The theoretical framework which we are developing refers essentially to Hubbert model in order to determine the peak oil in Tunisia and the exploitation speed of the remaining resources, while referring to the data supplied by the Directorate General for Energy. The study focuses on the comparison between the results of the several econometric adjustment techniques (linear, non-linear techniques, linear techniques with structural change and the non-parametric methods applied to the Tunisian oil production during the period going from 1966 to 2011. The prospective study through the econometric models has allowed us to determine the two dates scaring all energy executives, namely the peak which took place in the middle of the eighties and the finiteness of resources planned in 2028. The obtained results have shown that it remains 495 million barrels to be produced in Tunisia, bearing in mind that the data supplied by the authorities announces the figure of 420 million barrels of the remaining proved reserve in the Tunisian underground. Thereby, we have noticed a strong link between the physical models for reservoir flows and the empirical specifications based on the decline curves.

  10. SOLID FUEL OF HYDROCARBON, WOOD AND AGRICULTURAL WASTE FOR LOCAL HEAT SUPPLY SYSTEMS

    Directory of Open Access Journals (Sweden)

    B. M. Khroustalev

    2017-01-01

    Full Text Available In Belarus oil refining and oil producing industries are paid close attention. On the background of the active maintaining the level of oil processing and volume of oil extraction in our country and in the countries of the Eurasian Economic Union there is a steady formation of hydrocarbon-containing waste; therefore recycling of the latter is an urgent task to improve the competitiveness of production. The most cost-effective way of using hydrocarbon waste is the conversion of it into power resources. In this case it is possible to obtain significant power-saving and economic effect of the combined use of a hydrocarbon, wood, agricultural and other combustible waste, meanwhile improving the ecological situation at the sites of waste storage and creating a solid fuel with the necessary energy and specified physical-and-chemical properties. A comprehensive solution of a recycling problem makes it possible to use as energy resources a lot of waste that has not found application in other technologies, to produce alternative multi-component fuel which structure meets environmental and energy requirement for local heating systems. In addition, the implementation of such technology will make it possible to reduce power consumption of enterprises of various kinds that consume fuel and will also increase the share of local fuels in the energy balance of a particular region.

  11. Developing Model for Supply Chain Management - the Case of Croatia

    Directory of Open Access Journals (Sweden)

    E. Jurun

    2004-01-01

    Full Text Available This paper describes a model of supply chain management (SCM. It explains overall supply chain issues, strategic importance of SCM, supply chain strategies and an example of mathematical formulation. A supply chain is a global network of organizations that cooperate to improve the flows of material and information between suppliers and customers at the lowest cost and the highest speed. The objective of a supply chain is customer satisfaction. At the strategic level, a supply chain can be considered as being composed of five activities: buy, make, move, store and sell. Each activity is a module. The set of modules, along with its links, constitutes a model of the supply chain. Our paper presents some insights into the supply chain strategies of companies in Croatia. The major goal of this paper is to show a model for supply chain management in mathematical terms, with an example of mathematical formulation.

  12. The composite supply chain efficiency model: A case study of the Sishen-Saldanha supply chain

    Directory of Open Access Journals (Sweden)

    Leila L. Goedhals-Gerber

    2016-01-01

    Full Text Available As South Africa strives to be a major force in global markets, it is essential that South African supply chains achieve and maintain a competitive advantage. One approach to achieving this is to ensure that South African supply chains maximise their levels of efficiency. Consequently, the efficiency levels of South Africa’s supply chains must be evaluated. The objective of this article is to propose a model that can assist South African industries in becoming internationally competitive by providing them with a tool for evaluating their levels of efficiency both as individual firms and as a component in an overall supply chain. The Composite Supply Chain Efficiency Model (CSCEM was developed to measure supply chain efficiency across supply chains using variables identified as problem areas experienced by South African supply chains. The CSCEM is tested in this article using the Sishen-Saldanda iron ore supply chain as a case study. The results indicate that all three links or nodes along the Sishen-Saldanha iron ore supply chain performed well. The average efficiency of the rail leg was 97.34%, while the average efficiency of the mine and the port were 97% and 95.44%, respectively. The results also show that the CSCEM can be used by South African firms to measure their levels of supply chain efficiency. This article concludes with the benefits of the CSCEM.

  13. A VENSIM BASED ANALYSIS FOR SUPPLY CHAIN MODEL

    Directory of Open Access Journals (Sweden)

    Mohammad SHAMSUDDOHA

    2014-01-01

    Full Text Available The emphasis on supply chain has increased in recent years among academic and industry circles. In this paper, a supply chain model will be developed based on a case study of the poultry industry under the Vensim environment. System dynamics, supply chain, design science and case method under positivist and quantitative paradigm will be studied to develop a simulation model. The objectives of this paper are to review literature, develop a Vensim based simulation supply chain model, and examine the model qualitatively and quantitatively. The model will be also briefly discussed in relation of among forward, reverse and mainstream supply chain of the case.

  14. A tactical supply chain planning model with multiple flexibility options

    DEFF Research Database (Denmark)

    Esmaeilikia, Masoud; Fahimnia, Behnam; Sarkis, Joeseph

    2016-01-01

    Supply chain flexibility is widely recognized as an approach to manage uncertainty. Uncertainty in the supply chain may arise from a number of sources such as demand and supply interruptions and lead time variability. A tactical supply chain planning model with multiple flexibility options...... incorporated in sourcing, manufacturing and logistics functions can be used for the analysis of flexibility adjustment in an existing supply chain. This paper develops such a tactical supply chain planning model incorporating a realistic range of flexibility options. A novel solution method is designed...

  15. A Supply Chain Model at the Strategic Level

    OpenAIRE

    Chauhan, Satyaveer Singh; Proth, Jean-Marie

    2001-01-01

    In this paper, we introduce the notion of strategic model of supply chain. At the strategic level, a supply chain is always composed of five basic activities, denoted by Buy, Make, Move, Store and Sell. We present a specific model and show how to optimize the related supply chain from a strategic point of view

  16. Understanding data supply chains by using the Supply-Chain Operations Reference (SCOR) model

    CSIR Research Space (South Africa)

    Schmitz, Peter MU

    2007-09-01

    Full Text Available processes. This paper looks into the spatial data supply chain of ESI-GIS unit of Eskom and the use of an adapted SCOR model (GISDataSCOR) to model and analyse the supply chain. Spatial data needs to be sourced from various sources (SOURCE), which...

  17. Supply Chain as Complex Adaptive System and Its Modeling

    Institute of Scientific and Technical Information of China (English)

    MingmingWang

    2004-01-01

    Supply chain is a complex, hierarchical, integrated, open and dynamic network.Every node in the network is an independent business unit that unites other organizations to develop its value, the competition and cooperation between these units are basic impetus of the development and evolution of the supply chain system. The characteristics of supply chain as a complex adaptive system and its modeling are discussed in this paper, and use an example demonstrating the feasibility of CAS modeling in supply chain management study.

  18. Hydrocarbon- Generating Model of the Area Covered With Volcanic Rock

    Institute of Scientific and Technical Information of China (English)

    Guo Zhanqian; Zhang Yuwei

    2000-01-01

    The distribution of Oil & gas fields shows their close relationship with the most active tectonic regions. This is not a coincidence but having a scientific reasons. The crustal active regions, refer to the places where the active natural earthquake, volcanic activities, underground water happened, and the areas of the leaking off of natural gas to the surface of the crust. The magma of volcanic activities brings the organic "kitchen range body" hydrocarbon- generating model and inorganic genetic hydrocarbon to the regions covered by volcanic rock. Underground water brings a catalytic hydrocarbongenerating model for organic matter, and the leaking- off of H2 and CO2 contributes a synthetic hydrocarbon - generating model. Volcanic activities bring the assemblage of Source, Reservoir and Seal formed by the sediments and magma the sedimentary basins, and the hydrocarbon - generating system with a "water - volcano" binary structure is formed. All these conditions are favorable and excellent for the formation of oil & gas fields. The distribution of American oil & gas fields have very close relationship with the mines of Fe, Mn, Ct, Mo, W and V, deposits of Zn, Cu, V, Pb, Al and Hg, and the deposits of fluorite, sulfur, potassium salt, phosphate and halite, and the distribution of sulfate- chloride of river water. The reason why few oil & gas fields discovered in the regions covered by volcanic rock in western America maybe because of the view of "inconsistency between petroleum and volcano". Further more, It's very difficult to carry out a geophysical exploration in such kinds of regions.This paper examined a few hydrocarbon-generating models (systems) mentioned above and came up with some fresh ideas on the exploration in the areas covered with volcanic rocks.

  19. Developing a model for agile supply: an empirical study from Iranian pharmaceutical supply chain.

    Science.gov (United States)

    Rajabzadeh Ghatari, Ali; Mehralian, Gholamhossein; Zarenezhad, Forouzandeh; Rasekh, Hamid Reza

    2013-01-01

    Agility is the fundamental characteristic of a supply chain needed for survival in turbulent markets, where environmental forces create additional uncertainty resulting in higher risk in the supply chain management. In addition, agility helps providing the right product, at the right time to the consumer. The main goal of this research is therefore to promote supplier selection in pharmaceutical industry according to the formative basic factors. Moreover, this paper can configure its supply network to achieve the agile supply chain. The present article analyzes the supply part of supply chain based on SCOR model, used to assess agile supply chains by highlighting their specific characteristics and applicability in providing the active pharmaceutical ingredient (API). This methodology provides an analytical modeling; the model enables potential suppliers to be assessed against the multiple criteria using both quantitative and qualitative measures. In addition, for making priority of critical factors, TOPSIS algorithm has been used as a common technique of MADM model. Finally, several factors such as delivery speed, planning and reorder segmentation, trust development and material quantity adjustment are identified and prioritized as critical factors for being agile in supply of API.

  20. Developing a Model for Agile Supply: an Empirical Study from Iranian Pharmaceutical Supply Chain

    Science.gov (United States)

    Rajabzadeh Ghatari, Ali; Mehralian, Gholamhossein; Zarenezhad, Forouzandeh; Rasekh, Hamid Reza

    2013-01-01

    Agility is the fundamental characteristic of a supply chain needed for survival in turbulent markets, where environmental forces create additional uncertainty resulting in higher risk in the supply chain management. In addition, agility helps providing the right product, at the right time to the consumer. The main goal of this research is therefore to promote supplier selection in pharmaceutical industry according to the formative basic factors. Moreover, this paper can configure its supply network to achieve the agile supply chain. The present article analyzes the supply part of supply chain based on SCOR model, used to assess agile supply chains by highlighting their specific characteristics and applicability in providing the active pharmaceutical ingredient (API). This methodology provides an analytical modeling; the model enables potential suppliers to be assessed against the multiple criteria using both quantitative and qualitative measures. In addition, for making priority of critical factors, TOPSIS algorithm has been used as a common technique of MADM model. Finally, several factors such as delivery speed, planning and reorder segmentation, trust development and material quantity adjustment are identified and prioritized as critical factors for being agile in supply of API. PMID:24250689

  1. Coarse grained model for calculating the ion mobility of hydrocarbons

    Science.gov (United States)

    Kuroboshi, Y.; Takemura, K.

    2016-12-01

    Hydrocarbons are widely used as insulating compounds. However, their fundamental characteristics in conduction phenomena are not completely understood. A great deal of effort is required to determine reasonable ionic behavior from experiments because of their complicated procedures and tight controls of the temperature and the purity of the liquids. In order to understand the conduction phenomena, we have theoretically calculated the ion mobilities of hydrocarbons and investigated their characteristics using the coarse grained model in molecular dynamics simulations. We assumed a molecule of hydrocarbons to be a bead and simulated its dependence on the viscosity, electric field, and temperature. Furthermore, we verified the suitability of the conformation, scale size, and long-range interactions for the ion mobility. The results of the simulations show that the ion mobility values agree reasonably well with the values from Walden's rule and depend on the viscosity but not on the electric field. The ion mobility and self-diffusion coefficient exponentially increase with increasing temperature, while the activation energy decreases with increasing molecular size. These values and characteristics of the ion mobility are in reasonable agreement with experimental results. In the future, we can understand not only the ion mobilies of hydrocarbons in conduction, but also we can predict general phenomena in electrochemistry with molecular dynamics simulations.

  2. A modeling framework for supply chain simulation

    NARCIS (Netherlands)

    van der Zee, D.J.; van der Vorst, J.G.A.J.

    2002-01-01

    In many industries logistic optimization on a company scale is no longer sufficient to meet the competition. Nowadays, competition takes place between supply chains. Intrinsic to the concept and success of a supply chain is the tuning of the activities of the companies involved. Given the complexity

  3. UNCERTAINTY SUPPLY CHAIN MODEL AND TRANSPORT IN ITS DEPLOYMENTS

    Directory of Open Access Journals (Sweden)

    Fabiana Lucena Oliveira

    2014-05-01

    Full Text Available This article discusses the Model Uncertainty of Supply Chain, and proposes a matrix with their transportation modes best suited to their chains. From the detailed analysis of the matrix of uncertainty, it is suggested transportation modes best suited to the management of these chains, so that transport is the most appropriate optimization of the gains previously proposed by the original model, particularly when supply chains are distant from suppliers of raw materials and / or supplies.Here we analyze in detail Agile Supply Chains, which is a result of Uncertainty Supply Chain Model, with special attention to Manaus Industrial Center. This research was done at Manaus Industrial Pole, which is a model of industrial agglomerations, based in Manaus, State of Amazonas (Brazil, which contemplates different supply chains and strategies sharing same infrastructure of transport, handling and storage and clearance process and uses inbound for suppliers of raw material.  The state of art contemplates supply chain management, uncertainty supply chain model, agile supply chains, Manaus Industrial Center (MIC and Brazilian legislation, as a business case, and presents concepts and features, of each one. The main goal is to present and discuss how transport is able to support Uncertainty Supply Chain Model, in order to complete management model. The results obtained confirms the hypothesis of integrated logistics processes are able to guarantee attractivity for industrial agglomerations, and open discussions when the suppliers are far from the manufacturer center, in a logistics management.

  4. Modelling lean and green supply chain

    OpenAIRE

    Duarte, Susana Carla Vieira Lino Medina

    2013-01-01

    Dissertação para obtenção do Grau de Doutor em Engenharia Industrial The success of an organization depends on the effective control of its supply chain. It is important to recognize new opportunities for organization and its supply chain. In the last few years the approach to lean, agile, resilient and green supply chain paradigms has been addressed in the scientific literature. Research in this field shows that the integration of these concepts revealed some contradictions among so...

  5. Harvest choice and timber supply models for forest forecasting

    Science.gov (United States)

    Maksym Polyakov; David N Wear

    2010-01-01

    Timber supply has traditionally been modeled using aggregate data, whereas individual harvest choices have been shown to be sensitive to the vintage and condition of forest capital stocks. In this article, we build aggregate supply models for four roundwood products in a seven-state region of the US South directly from stand-level harvest choice models applied to...

  6. Beef Supply Response Under Uncertainty: An Autoregressive Distributed Lag Model

    OpenAIRE

    Mbaga, Msafiri Daudi; Coyle, Barry T.

    2003-01-01

    This is the first econometric study of dynamic beef supply response to incorporate risk aversion or, more specifically, price variance. Autoregressive distributed lag (ADL) models are estimated for cow-calf and feedlot operations using aggregate data for Alberta. In all cases, output price variance has a negative impact on output supply and investment. Moreover, the impacts of expected price on supply response are greater in magnitude and significance than in risk-neutral models.

  7. IT-Supported Modeling, Analysis and Design of Supply Chains

    Science.gov (United States)

    Nienhaus, Jörg; Alard, Robert; Sennheiser, Andreas

    A common language is a prerequisite for analyzing and optimizing supply chains. Based on experiences with three case studies, this paper identifies the aspects of a supply chain that have to be mapped to take informed decisions on its operations. Current, integrated modeling approaches for supply chains, like the SCOR and the GSCM model, will be analyzed and an advanced approach will be defined. The resulting approach takes advantage of IT-support.

  8. Understanding forest-derived biomass supply with GIS modelling

    DEFF Research Database (Denmark)

    Hock, B. K.; Blomqvist, L.; Hall, P.

    2012-01-01

    distribution, and the cost of delivery as forests are frequently remote from energy users. A GIS-based model was developed to predict supply curves of forest biomass material for a site or group of sites, both now and in the future. The GIS biomass supply model was used to assist the New Zealand Energy...

  9. A Bayesian Combination Forecasting Model for Retail Supply Chain Coordination

    Directory of Open Access Journals (Sweden)

    W.J. Wang

    2014-04-01

    Full Text Available Retailing plays an important part in modern economic development, and supply chain coordination is the research focus in retail operations management. This paper reviews the collaborative forecasting process within the framework of the collaborative planning, forecasting and replenishment of retail supply chain. A Bayesian combination forecasting model is proposed to integrate multiple forecasting resources and coordinate forecasting processes among partners in the retail supply chain. Based on simulation results for retail sales, the effectiveness of this combination forecasting model is demonstrated for coordinating the collaborative forecasting processes, resulting in an improvement of demand forecasting accuracy in the retail supply chain.

  10. Artificial Neural Network Model of Hydrocarbon Migration and Accumulation

    Institute of Scientific and Technical Information of China (English)

    刘海滨; 吴冲龙

    2002-01-01

    Based on the dynamic simulation of the 3-D structure the sedimentary modeling, the unit entity model has been adopted to transfer the heterogeneous complex pas sage system into limited simple homogeneous entity, and then the traditional dyn amic simulation has been used to calculate the phase and the drive forces of the hyd rocarbon , and the artificial neural network(ANN) technology has been applied to resolve such problems as the direction, velocity and quantity of the hydrocarbo n migration among the unit entities. Through simulating of petroleum migration a nd accumulation in Zhu Ⅲ depression, the complex mechanism of hydrocarbon migra tion and accumulation has been opened out.

  11. An empirical supply chain measurement model for a national egg producer based on the supply chain operations reference model

    Directory of Open Access Journals (Sweden)

    Christian Pretorius

    2013-05-01

    Full Text Available The management of a supply chain is both an offensive and defensive weapon that organisations can use to increase their competitive edge and capture a larger share of the market. In management science and supply chain management, multi-criteria decision making techniques have been used to solve a range of real-world problems. The problem is that many, if not most, companies in South Africa either do not have the required skills to use these decision-making techniques to improve or re-configure their supply chain, or they do not have a complete data set with which to model it effectively. In order to manage supply chains effectively, organisations at the very least need feedback on the performance of their entire supply chain. In this article, generic supply chain performance measures were used and a theoretical or empirical model was developed for the performance measurement of a national egg producer’s supply chain. It focused on a managerial program for the identification and management of their supply chain with recommendations for applying a measurement model. The overall performance of the supply chain as well as the five different performance attributes was presented to management in a dashboard format. This article could be used as a basis for future studies of supply chain performance measurement and the model could be used as a foundation for developing an improved version, not only for the egg industry, but for other industries as well. 

  12. System Dynamics Model for VMI&TPL Integrated Supply Chains

    Directory of Open Access Journals (Sweden)

    Guo Li

    2013-01-01

    Full Text Available This paper establishes VMI-APIOBPCS II model by extending VMI-APIOBPCS model from serial supply chain to distribution supply chain. Then TPL is introduced to this VMI distribution supply chain, and operational framework and process of VMI&TPL integrated supply chain are analyzed deeply. On this basis VMI-APIOBPCS II model is then changed to VMI&TPL-APIOBPCS model and VMI&TPL integrated operation mode is simulated. Finally, compared with VMI-APIOBPCS model, the TPL’s important role of goods consolidation and risk sharing in VMI&TPL integrated supply chain is analyzed in detail from the aspects of bullwhip effect, inventory level, service level, and so on.

  13. Model-based control of district heating supply temperature

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, Linn

    2010-11-15

    A model-based control strategy for the supply temperature to a district heating network was tested during three weeks at Idbaecken's CHP plant. The aim was to increase the electricity efficiency by a lower supply temperature, without risking the delivery reliability of heat to the district heating customers. Simulations and tests showed that at high loads, the mean supply temperature could be reduced by 4 deg C and the electricity production could be increased by 2.5%

  14. Supply chain disruption assessment based on the newsvendor model

    Directory of Open Access Journals (Sweden)

    Yisong Li

    2013-03-01

    Full Text Available Purpose: This paper focuses on supply chain disruption assessment.Design/methodology/approach: Newsvendor ModelFindings: As both cost and income principle will be taken into account in supply chain disruption assessment, we proposed in this paper: (1 the problem of supply chain disruption assessment is the trade-off problem. (2 the generic single period - newsvendor model can be used for capturing the critical point, which in tradition model stands for the demarcation point of profit but in this paper is the least costs considering disruption costs and expected revenues.Research limitations/implications: single period - newsvendor modelPractical implications: we give an example for test the effectiveness of this methodOriginality/value: to research supply chain risk in a new approach, that is: supply chain risk has both cost and profit. So we can assess it with trade-off method

  15. Model of service-oriented catering supply chain performance evaluation

    Directory of Open Access Journals (Sweden)

    Juanqiong Gou

    2013-03-01

    Full Text Available Purpose: The aim of this paper is constructing a performance evaluation model for service-oriented catering supply chain. Design/methodology/approach: With the research on the current situation of catering industry, this paper summarized the characters of the catering supply chain, and then presents the service-oriented catering supply chain model based on the platform of logistics and information. At last, the fuzzy AHP method is used to evaluate the performance of service-oriented catering supply chain. Findings: With the analysis of the characteristics of catering supply chain, we construct the performance evaluation model in order to guarantee the food safety, logistics efficiency, price stability and so on. Practical implications: In order to evolve an efficient and effective service supply chain, it can not only used to own enterprise improvement, but also can be used for selecting different customers, to choose a different model of development. Originality/value: This paper has a new definition of service-oriented catering supply chain. And it offers a model to evaluate the performance of this catering supply chain.

  16. Inverse thermal history modelling as a hydrocarbon exploration tool

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, K. [Imperial College of Science, Technology and Medicine, London (United Kingdom). TH Huxley School of Environment, Earth Science and Engineering

    1998-12-31

    Thermal history modelling is a significant part of hydrocarbon exploration and resource assessment. Its primary use is to predict the volume and timing of hydrocarbon generation as a sedimentary basin evolves on timescales of 10{sup 7}-10{sup 8} years. Forward modelling is commonly used to constrain the thermal history in sedimentary basins. Alternatively, inversion schemes may be used which have many advantages over the conventional forward modelling approach. An example of an inversion approach is presented here, wherein the preferred philosophy is to find the least complex model that fits the data. In this case, we estimate a heat flow function (of time) which provides an adequate fit to the available thermal indicator calibration data. The function is also constrained to be smooth, in either a first or second derivative sense. Extra complexity or structure is introduced into the function only where required to fit the data and the regularization stabilizes the inversion. The general formulation is presented and a real data example from the North Slope, Alaska is discussed. (author)

  17. A CONCEPTUAL FRAMEWORK FOR SUSTAINABLE POULTRY SUPPLY CHAIN MODEL

    Directory of Open Access Journals (Sweden)

    Mohammad SHAMSUDDOHA

    2013-12-01

    Full Text Available Now a day, sustainable supply chain is the crucially considerable matter for future focused industries. As a result, attention in supply chain management has increasingly amplified since the 1980s when firms discovered its benefits of mutual relationships within and beyond their own organization. This is why, concern researchers are trying hard to develop new theory or model which might help the corporate sector for achieving sustainability in their supply chains. This kind of reflection can be seen by the number of papers published and in particular by journal since 1980. The objectives of this paper are twofold. First, it offers a literature review on sustainable supply chain management taking papers published in last three decades. Second, it offers a conceptual sustainable supply chain process model in light of triple bottom line theory. The model has been developed by taking in-depth interview of an entrepreneur from a Poultry case industry in Bangladesh.

  18. Model for Estimation Urban Transportation Supply-Demand Ratio

    Directory of Open Access Journals (Sweden)

    Chaoqun Wu

    2015-01-01

    Full Text Available The paper establishes an estimation model of urban transportation supply-demand ratio (TSDR to quantitatively describe the conditions of an urban transport system and to support a theoretical basis for transport policy-making. This TSDR estimation model is supported by the system dynamic principle and the VENSIM (an application that simulates the real system. It was accomplished by long-term observation of eight cities’ transport conditions and by analyzing the estimated results of TSDR from fifteen sets of refined data. The estimated results indicate that an urban TSDR can be classified into four grades representing four transport conditions: “scarce supply,” “short supply,” “supply-demand balance,” and “excess supply.” These results imply that transport policies or measures can be quantified to facilitate the process of ordering and screening them.

  19. Hybrid modeling and empirical analysis of automobile supply chain network

    Science.gov (United States)

    Sun, Jun-yan; Tang, Jian-ming; Fu, Wei-ping; Wu, Bing-ying

    2017-05-01

    Based on the connection mechanism of nodes which automatically select upstream and downstream agents, a simulation model for dynamic evolutionary process of consumer-driven automobile supply chain is established by integrating ABM and discrete modeling in the GIS-based map. Firstly, the rationality is proved by analyzing the consistency of sales and changes in various agent parameters between the simulation model and a real automobile supply chain. Second, through complex network theory, hierarchical structures of the model and relationships of networks at different levels are analyzed to calculate various characteristic parameters such as mean distance, mean clustering coefficients, and degree distributions. By doing so, it verifies that the model is a typical scale-free network and small-world network. Finally, the motion law of this model is analyzed from the perspective of complex self-adaptive systems. The chaotic state of the simulation system is verified, which suggests that this system has typical nonlinear characteristics. This model not only macroscopically illustrates the dynamic evolution of complex networks of automobile supply chain but also microcosmically reflects the business process of each agent. Moreover, the model construction and simulation of the system by means of combining CAS theory and complex networks supplies a novel method for supply chain analysis, as well as theory bases and experience for supply chain analysis of auto companies.

  20. Modeling sustainability in renewable energy supply chain systems

    Science.gov (United States)

    Xie, Fei

    This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate "environmental thinking" into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain under uncertainties. All models are mixed integer programs, which also involves multi-objective programming method and two-stage/multistage stochastic programming methods. In particular for the long-term sequential planning under uncertainties, to reduce the computational challenges due to the exponential expansion of the scenario tree, I also developed efficient ND-Max method which is more efficient than CPLEX and Nested Decomposition method. Through result analysis of four independent studies, it is found that the proposed modeling frameworks can effectively improve the economic performance, enhance environmental benefits and reduce risks due to systems uncertainties for the biofuel supply chain systems.

  1. A Study on Supply Model of Rural Highways in China

    Directory of Open Access Journals (Sweden)

    Wang Dexiang

    2015-01-01

    Full Text Available Rural highway has a significant impact to build a moderately prosperous society in all aspects, and it is an important critical infrastructure to build harmonious society. Highway has its own economics attributes, and rural highway also has its own characteristics. This paper combines with rural highway characteristics to analyze the supply model and problems of rural highway. It summarizes several mixed supply models of rural highways.

  2. A conceptual model for SMEs mechatronics supply chain.

    OpenAIRE

    Tounsi, Jihène; Boissiere, Julien; Habchi, Georges

    2010-01-01

    17; International audience; Nowadays, in order to meet the demands of the global dynamic market and eliminate its disturbances, the supply chain and its integration across different organizations has become a competitive business advantage along the production processes. In particular, the mechatronic industry is very sensitive to these requirements. Our research deals with modelling the supply chain in order to manage and implement a simulation platform. Basically, we develop a modelling sol...

  3. Hybrid Modeling and Simulation of Automotive Supply Chain Network

    Directory of Open Access Journals (Sweden)

    Wen Wang

    2013-07-01

    Full Text Available According to the operation of automotive supply chain and the features of various simulation methods, we create and simulate a automotive supply chain network model with the core enterprise of two vehicle manufacturers, consisting of several parts suppliers, vehicle distributors and logistics service providers. On this basis of a conceptual model including the establishment of enterprise layer, business layer and operation layer, we establish a detailed model of the network system according to the network structure of automotive supply chain, the operation process and the internal business process of core enterprises; then we use System Dynamics (SD, Discrete Event Simulation (DES and Agent Based Modeling (ABM to describe the operating state of each node in the network model. We execute and analyze the simulation model of the whole network system described by Anylogic, using the results of the distributors’ inventory, inventory cost and customer’s satisfaction to prove the effectiveness of the model.

  4. Oil and gas supply and economics model for Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Partowidagdo, W.

    1987-01-01

    The central goal of this study was to estimate the potential of Indonesia's unexplored basins to continue to provide income to the country. Specific objectives were: (1) Build a model that estimates how the level of efforts by the contractors in a basin will vary as physical properties, government's tax rate, and hydrocarbon prices vary. The basic assumption underlying the model is that a contractor adapts his efforts in an attempt to maximize his discounted profit. (2) Use the model to analyze the impact of the Government's tax policy in each Indonesian basin. The model consists of three submodels: discovery, development and economics. The main program uses these three submodels iteratively to determine optimum investment, which give maximum net revenue for the contractors, as a function of tax rate and hydrocarbon price for each basin in Indonesia. Remaining recoverable reserves up to the contractors' economic limit and to government's economic limit were calculated for each of the 40 known basins in Indonesia. As expected, the following conditions cause calculated recoverables to increase: (1) higher hydrocarbon prices; (2) higher fraction of discovered gas developed and sold; (3) lower cost in a basin; (a) less remote area, (b) shallower sea, (c) shallower formation; (4) higher fraction of oil in a basin (oil is more profitable than gas).

  5. Profit Analysis and Supply Chain Planning Model for Closed-Loop Supply Chain in Fashion Industry

    OpenAIRE

    Jisoo Oh; Bongju Jeong

    2014-01-01

    In recent decades, due to market growth and use of synthetic fiber, the fashion industry faces a rapid increase of CO 2 emission throughout the production cycle and raises environmental issues in recovery processing. This study proposes a closed-loop supply chain (CLSC) structure in fashion industry and develops its planning model as multi-objective mixed integer linear programming to find an optimal trade-off between CLSC profit and CO 2 emission. The planning model is associated with the pr...

  6. Demand Activated Manufacturing Architecture (DAMA) model for supply chain collaboration

    Energy Technology Data Exchange (ETDEWEB)

    CHAPMAN,LEON D.; PETERSEN,MARJORIE B.

    2000-03-13

    The Demand Activated Manufacturing Architecture (DAMA) project during the last five years of work with the U.S. Integrated Textile Complex (retail, apparel, textile, and fiber sectors) has developed an inter-enterprise architecture and collaborative model for supply chains. This model will enable improved collaborative business across any supply chain. The DAMA Model for Supply Chain Collaboration is a high-level model for collaboration to achieve Demand Activated Manufacturing. The five major elements of the architecture to support collaboration are (1) activity or process, (2) information, (3) application, (4) data, and (5) infrastructure. These five elements are tied to the application of the DAMA architecture to three phases of collaboration - prepare, pilot, and scale. There are six collaborative activities that may be employed in this model: (1) Develop Business Planning Agreements, (2) Define Products, (3) Forecast and Plan Capacity Commitments, (4) Schedule Product and Product Delivery, (5) Expedite Production and Delivery Exceptions, and (6) Populate Supply Chain Utility. The Supply Chain Utility is a set of applications implemented to support collaborative product definition, forecast visibility, planning, scheduling, and execution. The DAMA architecture and model will be presented along with the process for implementing this DAMA model.

  7. A Multiobjective Optimization Model in Automotive Supply Chain Networks

    Directory of Open Access Journals (Sweden)

    Abdolhossein Sadrnia

    2013-01-01

    Full Text Available In the new decade, green investment decisions are attracting more interest in design supply chains due to the hidden economic benefits and environmental legislative barriers. In this paper, a supply chain network design problem with both economic and environmental concerns is presented. Therefore, a multiobjective optimization model that captures the trade-off between the total logistics cost and CO2 emissions is proposed. With regard to the complexity of logistic networks, a new multiobjective swarm intelligence algorithm known as a multiobjective Gravitational search algorithm (MOGSA has been implemented for solving the proposed mathematical model. To evaluate the effectiveness of the model, a comprehensive set of numerical experiments is explained. The results obtained show that the proposed model can be applied as an effective tool in strategic planning for optimizing cost and CO2 emissions in an environmentally friendly automotive supply chain.

  8. How altruism works: An evolutionary model of supply networks

    Science.gov (United States)

    Ge, Zehui; Zhang, Zi-Ke; Lü, Linyuan; Zhou, Tao; Xi, Ning

    2012-02-01

    Recently, supply networks have attracted increasing attention from the scientific community. However, it lacks serious consideration of social preference in Supply Chain Management. In this paper, we develop an evolutionary decision-making model to characterize the effects of suppliers' altruism in supply networks, and find that the performances of both suppliers and supply chains are improved by introducing the role of altruism. Furthermore, an interesting and reasonable phenomenon is discovered that the suppliers' and whole network's profits do not change monotonously with suppliers' altruistic preference, η, but reach the best at η=0.6 and η=0.4, respectively. This work may shed some light on the in-depth understanding of the effects of altruism for both research and commercial applications.

  9. Cache County Water Demand/Supply Model

    OpenAIRE

    Hughes, Trevor C.; Norby, Gregory J.; Thyagarajan, Laxman

    1996-01-01

    This report descibes a municipal water demand forecasting model for use in areas of mixed rural and urban housing types. A series of residential demand functions were derived which forecast water demand based on the ype and density of housing and season. Micro sampling techniques were used to correlate water use data and explanatory variable data for low, medium, and high density housing. The demand functions were...

  10. Using Supply, Demand, and the Cournot Model to Understand Corruption

    Science.gov (United States)

    Hayford, Marc D.

    2007-01-01

    The author combines the supply and demand model of taxes with a Cournot model of bribe takers to develop a simple and useful framework for understanding the effect of corruption on economic activity. There are many examples of corruption in both developed and developing countries. Because corruption decreases the level of economic activity and…

  11. Using Supply, Demand, and the Cournot Model to Understand Corruption

    Science.gov (United States)

    Hayford, Marc D.

    2007-01-01

    The author combines the supply and demand model of taxes with a Cournot model of bribe takers to develop a simple and useful framework for understanding the effect of corruption on economic activity. There are many examples of corruption in both developed and developing countries. Because corruption decreases the level of economic activity and…

  12. The hydrocarbon generation mechanism and the threestage type model of hydrocarbon generation for carbonate source rocks

    Institute of Scientific and Technical Information of China (English)

    王兆云; 程克明

    1997-01-01

    The diagenetic mechanism and process of carbonate rocks, which is different to that of clastic rocks, decides the existence of different existing state organic matters in carbonate rocks. This has been verified by both the microscopic observation of organic petrology and the analysis of organic geochemistry of many samples. Based on the hydrous pyrolysis simulation experiment of the low-mature carbonate rocks, the contrasting study on the yield and their geochemistry characteristics of different existing state soluble organic matters of a series of various maturity samples shows that the different existing state organic matters make different contributions to hydrocarbon generation during every evolution state. So that, the hydrocarbon generation process of carbonate rocks can be summarized as the following three stages; the first is the direct degradation of biogenic bitumen macromolecules during the immature stage, the second is the thermal degradation of a large amount of kerogen at the mature stage,

  13. Modeling Carbon and Hydrocarbon Molecular Structures in EZTB

    Science.gov (United States)

    Lee, Seungwon; vonAllmen, Paul

    2007-01-01

    A software module that models the electronic and mechanical aspects of hydrocarbon molecules and carbon molecular structures on the basis of first principles has been written for incorporation into, and execution within, the Easy (Modular) Tight-Binding (EZTB) software infrastructure, which is summarized briefly in the immediately preceding article. Of particular interest, this module can model carbon crystals and nanotubes characterized by various coordinates and containing defects, without need to adjust parameters of the physical model. The module has been used to study the changes in electronic properties of carbon nanotubes, caused by bending of the nanotubes, for potential utility as the basis of a nonvolatile, electriccharge- free memory devices. For example, in one application of the module, it was found that an initially 50-nmlong carbon, (10,10)-chirality nanotube, which is a metallic conductor when straight, becomes a semiconductor with an energy gap of .3 meV when bent to a lateral displacement of 4 nm at the middle.

  14. A Decision Model for Selecting Participants in Supply Chain

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to satisfy the rapid changing requirements of customers, enterprises must cooperate with each other to form supply chain. The first and the most important stage in the forming of supply chain is the selection of participants. The article proposes a two-staged decision model to select partners. The first stage is the inter company comparison in each business process to select highefficiency candidate based on inside variables. The next stage is to analyse the combination of different candidates in order to select the most perfect partners according to a goal-programming model.

  15. Reliability modelling - PETROBRAS 2010 integrated gas supply chain

    Energy Technology Data Exchange (ETDEWEB)

    Faertes, Denise; Heil, Luciana; Saker, Leonardo; Vieira, Flavia; Risi, Francisco; Domingues, Joaquim; Alvarenga, Tobias; Carvalho, Eduardo; Mussel, Patricia

    2010-09-15

    The purpose of this paper is to present the innovative reliability modeling of Petrobras 2010 integrated gas supply chain. The model represents a challenge in terms of complexity and software robustness. It was jointly developed by PETROBRAS Gas and Power Department and Det Norske Veritas. It was carried out with the objective of evaluating security of supply of 2010 gas network design that was conceived to connect Brazilian Northeast and Southeast regions. To provide best in class analysis, state of the art software was used to quantify the availability and the efficiency of the overall network and its individual components.

  16. A Data Mining Approach to Modelling of Water Supply Assets

    DEFF Research Database (Denmark)

    Babovic, V.; Drecourt, J.; Keijzer, M.

    2002-01-01

    supply assets are mainly situated underground, and therefore not visible and under the influence of various highly unpredictable forces. This paper proposes the use of advanced data mining methods in order to determine the risks of pipe bursts. For example, analysis of the database of already occurred...... with the choice of pipes to be replaced, the outlined approach opens completely new avenues in asset modelling. The condition of an asset such as a water supply network deteriorates with age. With reliable risk models, addressing the evolution of risk with aging asset, it is now possible to plan optimal...

  17. Quantitative Model for Supply Chain Visibility: Process Capability Perspective

    Directory of Open Access Journals (Sweden)

    Youngsu Lee

    2016-01-01

    Full Text Available Currently, the intensity of enterprise competition has increased as a result of a greater diversity of customer needs as well as the persistence of a long-term recession. The results of competition are becoming severe enough to determine the survival of company. To survive global competition, each firm must focus on achieving innovation excellence and operational excellence as core competency for sustainable competitive advantage. Supply chain management is now regarded as one of the most effective innovation initiatives to achieve operational excellence, and its importance has become ever more apparent. However, few companies effectively manage their supply chains, and the greatest difficulty is in achieving supply chain visibility. Many companies still suffer from a lack of visibility, and in spite of extensive research and the availability of modern technologies, the concepts and quantification methods to increase supply chain visibility are still ambiguous. Based on the extant researches in supply chain visibility, this study proposes an extended visibility concept focusing on a process capability perspective and suggests a more quantitative model using Z score in Six Sigma methodology to evaluate and improve the level of supply chain visibility.

  18. Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Conversion Pathway: Biological Conversion of Sugars to Hydrocarbons The 2017 Design Case

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J Bonner; Garold L. Gresham; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

    2013-09-01

    The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL conducted a campaign to quantify the economics and sustainability of moving biomass from standing in the field or stand to the throat of the biomass conversion process. The goal of this program was to establish the current costs based on conventional equipment and processes, design improvements to the current system, and to mark annual improvements based on higher efficiencies or better designs. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $35/dry ton. This goal was successfully achieved in 2012 by implementing field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. Looking forward to 2017, the programmatic target is to supply biomass to the conversion facilities at a total cost of $80/dry ton and on specification with in-feed requirements. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, abundant, low-cost feedstock. If this goal is not achieved, biofuel plants are destined to be small and/or clustered in select regions of the country that have a lock on low-cost feedstock. To put the 2017 cost target into perspective of past accomplishments of the cellulosic ethanol pathway, the $80 target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all

  19. Partner Selection Optimization Model of Agricultural Enterprises in Supply Chain

    Directory of Open Access Journals (Sweden)

    Feipeng Guo

    2013-10-01

    Full Text Available With more and more importance of correctly selecting partners in supply chain of agricultural enterprises, a large number of partner evaluation techniques are widely used in the field of agricultural science research. This study established a partner selection model to optimize the issue of agricultural supply chain partner selection. Firstly, it constructed a comprehensive evaluation index system after analyzing the real characteristics of agricultural supply chain. Secondly, a heuristic method for attributes reduction based on rough set theory and principal component analysis was proposed which can reduce multiple attributes into some principal components, yet retaining effective evaluation information. Finally, it used improved BP neural network which has self-learning function to select partners. The empirical analysis on an agricultural enterprise shows that this model is effective and feasible for practical partner selection.

  20. Profit Analysis and Supply Chain Planning Model for Closed-Loop Supply Chain in Fashion Industry

    Directory of Open Access Journals (Sweden)

    Jisoo Oh

    2014-12-01

    Full Text Available In recent decades, due to market growth and use of synthetic fiber, the fashion industry faces a rapid increase of CO2 emission throughout the production cycle and raises environmental issues in recovery processing. This study proposes a closed-loop supply chain (CLSC structure in fashion industry and develops its planning model as multi-objective mixed integer linear programming to find an optimal trade-off between CLSC profit and CO2 emission. The planning model is associated with the profit analysis of each member in CLSC to find the optimal price of products on CLSC network. The model determines optimal production, transportation, and inventory quantities on CLSC network. The proposed models are validated using numerical experiments and sensitivity analyses, and from the results some managerial insights are addressed.

  1. Turbulence radiation interaction modeling in hydrocarbon pool fire simulations

    Energy Technology Data Exchange (ETDEWEB)

    BURNS,SHAWN P.

    1999-12-01

    The importance of turbulent fluctuations in temperature and species concentration in thermal radiation transport modeling for combustion applications is well accepted by the radiation transport and combustion communities. A number of experimental and theoretical studies over the last twenty years have shown that fluctuations in the temperature and species concentrations may increase the effective emittance of a turbulent flame by as much as 50% to 300% over the value that would be expected from the mean temperatures and concentrations. With the possibility of such a large effect on the principal mode of heat transfer from a fire, it is extremely important for fire modeling efforts that turbulence radiation interaction be well characterized and possible modeling approaches understood. Toward this end, this report seeks to accomplish three goals. First, the principal turbulence radiation interaction closure terms are defined. Second, an order of magnitude analysis is performed to understand the relative importance of the various closure terms. Finally, the state of the art in turbulence radiation interaction closure modeling is reviewed. Hydrocarbon pool fire applications are of particular interest in this report and this is the perspective from which this review proceeds. Experimental and theoretical analysis suggests that, for this type of heavily sooting flame, the turbulent radiation interaction effect is dominated by the nonlinear dependence of the Planck function on the temperature. Additional effects due to the correlation between turbulent fluctuations in the absorptivity and temperature may be small relative to the Planck function effect for heavily sooting flames. This observation is drawn from a number of experimental and theoretical discussions. Nevertheless, additional analysis and data is needed to validate this observation for heavily sooting buoyancy dominated plumes.

  2. To develop an integrated model for green supply chain | Tajabadi ...

    African Journals Online (AJOL)

    To develop an integrated model for green supply chain. ... manufacturers, warehouses and dealers in such a way that system costs to ... design including the localization of facilities, allocation flow among facilities and routing decisions. The issue is to determine the number, location and capacity levels of distribution centers, ...

  3. Quantitative modelling in design and operation of food supply systems

    NARCIS (Netherlands)

    Beek, van P.

    2004-01-01

    During the last two decades food supply systems not only got interest of food technologists but also from the field of Operations Research and Management Science. Operations Research (OR) is concerned with quantitative modelling and can be used to get insight into the optimal configuration and opera

  4. Tactical supply chain planning models with inherent flexibility

    DEFF Research Database (Denmark)

    Esmaeilikia, Masoud; Fahimnia, Behnam; Sarkis, Joeseph

    2016-01-01

    Supply chains (SCs) can be managed at many levels. The use of tactical SC planning models with multiple flexibility options can help manage the usual operations efficiently and effectively, whilst improve the SC resiliency in response to inherent environmental uncertainties. This paper defines...

  5. Supplier Selection in Virtual Enterprise Model of Manufacturing Supply Network

    Science.gov (United States)

    Kaihara, Toshiya; Opadiji, Jayeola F.

    The market-based approach to manufacturing supply network planning focuses on the competitive attitudes of various enterprises in the network to generate plans that seek to maximize the throughput of the network. It is this competitive behaviour of the member units that we explore in proposing a solution model for a supplier selection problem in convergent manufacturing supply networks. We present a formulation of autonomous units of the network as trading agents in a virtual enterprise network interacting to deliver value to market consumers and discuss the effect of internal and external trading parameters on the selection of suppliers by enterprise units.

  6. Oil Refinery Supply Chain Modelling Using Pipe Transportation Simulator

    Directory of Open Access Journals (Sweden)

    Jakub Dyntar

    2012-03-01

    Full Text Available This paper describes an application of Pipe Transportation Simulator (PTS in oil refinery supply chain modelling. We develop the simulator in Witness simulation software environment using MS Excel for input data loading and outputs upgrading. PTS is particularly suitable for “what-if” analysis in the crude oil, fuels or gas supply chains where the products are transported among warehouses and refineries through the pipe lines. To discuss the basic functionality of proposed simulator we employ PTS to simulate a real oil refinery supply chain consisting of 16 warehouses and 3 refineries placed in the Czech Republic and Slovakia. The refineries and warehouses are connected together with 21 pipe lines. PTS is used to verify a plan of fuels movements among warehouses and refineries as well as a plan of repairs of certain pipe lines in the selected time period of the length of 30 days.

  7. Supply chain management models, applications, and research directions

    CERN Document Server

    Pardalos, Panos; Romeijn, H

    2005-01-01

    This work brings together some of the most up to date research in the application of operations research and mathematical modeling te- niques to problems arising in supply chain management and e-Commerce. While research in the broad area of supply chain management enc- passes a wide range of topics and methodologies, we believe this book provides a good snapshot of current quantitative modeling approaches, issues, and trends within the field. Each chapter is a self-contained study of a timely and relevant research problem in supply chain mana- ment. The individual works place a heavy emphasis on the application of modeling techniques to real world management problems. In many instances, the actual results from applying these techniques in practice are highlighted. In addition, each chapter provides important mana- rial insights that apply to general supply chain management practice. The book is divided into three parts. The first part contains ch- ters that address the new and rapidly growing role of the inte...

  8. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    Science.gov (United States)

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  9. Fuel supply of direct carbon fuel cells via thermal decomposition of hydrocarbons inside a porous Ni anode

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Hak Gyu; Li, Cheng Guo; Jalalabadi, Tahereh; Lee, Dong Geun [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of)

    2015-06-15

    This study offers a novel method for improving the physical contact between the anode and fuel in a direct carbon fuel cell (DCFC): a direct generation of carbon in a porous Ni anode through the thermal decomposition of gaseous hydrocarbons. Three kinds of alkane hydrocarbons with different carbon numbers (CH4, C2H6, and C3H8) are tested. From electron microscope observations of the carbon particles generated from each hydrocarbon, we confirm that more carbon spheres (CS), carbon nanotubes (CNT), and carbon nanofibers (CNF) were identified with increasing carbon number. Raman scattering results revealed that the carbon samples became less crystalline and more flexible with increasing carbon number. DCFC performance was measured at 700 degree Celsius with the anode fueled by the same mass of each carbon sample. One-dimensional carbon fuels of CNT and CNF more actively produced and had power densities 148 and 210 times higher than that of the CS, respectively. This difference is partly attributed to the findings that the less-crystalline CNT and CNF have much lower charge transfer resistances than the CS.

  10. Applying a Dynamic Resource Supply Model in a Smart Grid

    Directory of Open Access Journals (Sweden)

    Kaiyu Wan

    2014-09-01

    Full Text Available Dynamic resource supply is a complex issue to resolve in a cyber-physical system (CPS. In our previous work, a resource model called the dynamic resource supply model (DRSM has been proposed to handle resources specification, management and allocation in CPS. In this paper, we are integrating the DRSM with service-oriented architecture and applying it to a smart grid (SG, one of the most complex CPS examples. We give the detailed design of the SG for electricity charging request and electricity allocation between plug-in hybrid electric vehicles (PHEV and DRSM through the Android system. In the design, we explain a mechanism for electricity consumption with data collection and re-allocation through ZigBee network. In this design, we verify the correctness of this resource model for expected electricity allocation.

  11. Quantitative Methods in Supply Chain Management Models and Algorithms

    CERN Document Server

    Christou, Ioannis T

    2012-01-01

    Quantitative Methods in Supply Chain Management presents some of the most important methods and tools available for modeling and solving problems arising in the context of supply chain management. In the context of this book, “solving problems” usually means designing efficient algorithms for obtaining high-quality solutions. The first chapter is an extensive optimization review covering continuous unconstrained and constrained linear and nonlinear optimization algorithms, as well as dynamic programming and discrete optimization exact methods and heuristics. The second chapter presents time-series forecasting methods together with prediction market techniques for demand forecasting of new products and services. The third chapter details models and algorithms for planning and scheduling with an emphasis on production planning and personnel scheduling. The fourth chapter presents deterministic and stochastic models for inventory control with a detailed analysis on periodic review systems and algorithmic dev...

  12. Modeling and Robustness of Knowledge Network in Supply Chain

    Institute of Scientific and Technical Information of China (English)

    王道平; 沈睿芳

    2014-01-01

    The growth and evolution of the knowledge network in supply chain can be characterized by dynamic growth clustering and non-homogeneous degree distribution. The networks with the above characteristics are also known as scale-free networks. In this paper, the knowledge network model in supply chain is established, in which the preferential attachment mechanism based on the node strength is adopted to simulate the growth and evolution of the network. The nodes in the network have a certain preference in the choice of a knowledge partner. On the basis of the network model, the robustness of the three network models based on different preferential attachment strategies is in-vestigated. The robustness is also referred to as tolerances when the nodes are subjected to random destruction and malicious damage. The simulation results of this study show that the improved network has higher connectivity and stability.

  13. Lifetime models of female labor supply, wage rates, and fertility.

    Science.gov (United States)

    Carliner, G; Robinson, C; Tomes, N

    1984-01-01

    A simple 1 period lifetime model is specified in which schooling is part of the lifetime period. This implies that an adding-up constraint is imposed on the uses of time in the lifetime including schooling, which may induce a negative correlation between years of schooling and years in the market, while producing a positive correlation between years of schooling and the fraction of the postschool lifetime spent in the market. The model is used to interpret empirical analyses based on alternative measures of lifetime labor supply and on alternative specifications of which variables may be treated as exogenous. In the empirical analysis the retrospective and longitudinal aspects of the newly available National Longitudinal Survey of Women is used to construct a measure of the fraction of the lifetime supplied to the market and measures of the lifetime wage rates of both the husband and the wife. The empirical results take the lifetime model of labor supply seriously in that the empirical measures of labor supply and wage rates bear a much closer resemblance to the theoretical concepts than measures typically employed in the literature. The estimates indicate that the "plausible assumptions" required for the true coefficient on fertility in a labor supply equation to be zero are fulfilled. These estimates are compared with those obtained using current measures as proxies for lifetime variables. Based on these estimates, an explanation is offered for the apparent contradiction between the findings of studies using a simultaneous equations approach that report no effect of fertility on female labor supply and the strong depressing effect of children on (current) labor supply obtained from research that treats children as exogenous. Current female hours appear more responsive to husbands' current earnings and female education than is the case with the lifetime variables. There are marked differences in the effects of race. The lifetime hours of white women are only some

  14. Numerical modeling of temperature and species distributions in hydrocarbon reservoirs

    Science.gov (United States)

    Bolton, Edward W.; Firoozabadi, Abbas

    2014-01-01

    We examine bulk fluid motion and diffusion of multicomponent hydrocarbon species in porous media in the context of nonequilibrium thermodynamics, with particular focus on the phenomenology induced by horizontal thermal gradients at the upper and lower horizontal boundaries. The problem is formulated with respect to the barycentric (mass-averaged) frame of reference. Thermally induced convection, with fully time-dependent temperature distributions, can lead to nearly constant hydrocarbon composition, with minor unmixing due to thermal gradients near the horizontal boundaries. Alternately, the composition can be vertically segregated due to gravitational effects. Independent and essentially steady solutions have been found to depend on how the compositions are initialized in space and may have implications for reservoir history. We also examine injection (to represent filling) and extraction (to represent leakage) of hydrocarbons at independent points and find a large distortion of the gas-oil contact for low permeability.

  15. Hydrocarbon Fuel Thermal Performance Modeling based on Systematic Measurement and Comprehensive Chromatographic Analysis

    Science.gov (United States)

    2016-07-31

    distribution unlimited Hydrocarbon Fuel Thermal Performance Modeling based on Systematic Measurement and Comprehensive Chromatographic Analysis Matthew...Technical Note 3. DATES COVERED (From - To) 04 January 2016 - 31 July 2016 4. TITLE AND SUBTITLE Hydrocarbon Fuel Thermal Performance Modeling based on...Systematic Measurement and Comprehensive Chromatographic Analysis 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

  16. Effective food supply chains; generating, modelling and evaluating supply chain scenarios

    NARCIS (Netherlands)

    Vorst, van der J.G.A.J.

    2000-01-01

    Logistical co-ordination in FMCG supply chains

    The overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to find an efficient and

  17. Effective food supply chains : generating, modelling and evaluating supply chain scenarios

    NARCIS (Netherlands)

    Vorst, van der J.G.A.J.

    2000-01-01

    Logistical co-ordination in FMCG supply chains

    The overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to

  18. Effective food supply chains : generating, modelling and evaluating supply chain scenarios

    NARCIS (Netherlands)

    Vorst, van der J.G.A.J.

    2000-01-01

    Logistical co-ordination in FMCG supply chains

    The overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to f

  19. Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

    Directory of Open Access Journals (Sweden)

    V. Mugica

    2002-01-01

    Full Text Available With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas, asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

  20. Capacity expansion modelling to aid water supply investment decisions

    OpenAIRE

    Padula, S

    2015-01-01

    Increasing population, economic development, and environmental changes imply that maintaining the water supply-demand balance will remain a top priority. Water resource systems may need to be expanded in order to respond to demand growth. Capacity expansion studies can be used to answer the question of what the optimal expansion size, timing and location of new infrastructure should be. This thesis develops and applies capacity expansion optimisation modelling approaches. We begin with the 'E...

  1. Supply Chain Modeling: Downstream Risk Assessment Methodology (DRAM)

    Science.gov (United States)

    2013-12-05

    Supply Chain Modeling: Downstream Risk Assessment Methodology (DRAM) Dr. Sean Barnett December 5, 2013 Institute for Defense Analyses Alexandria, Virginia DMSMS Conference 2013 These Slides are Unclassified and Not Proprietary Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the

  2. Modelling and analysis of workflow for lean supply chains

    Science.gov (United States)

    Ma, Jinping; Wang, Kanliang; Xu, Lida

    2011-11-01

    Cross-organisational workflow systems are a component of enterprise information systems which support collaborative business process among organisations in supply chain. Currently, the majority of workflow systems is developed in perspectives of information modelling without considering actual requirements of supply chain management. In this article, we focus on the modelling and analysis of the cross-organisational workflow systems in the context of lean supply chain (LSC) using Petri nets. First, the article describes the assumed conditions of cross-organisation workflow net according to the idea of LSC and then discusses the standardisation of collaborating business process between organisations in the context of LSC. Second, the concept of labelled time Petri nets (LTPNs) is defined through combining labelled Petri nets with time Petri nets, and the concept of labelled time workflow nets (LTWNs) is also defined based on LTPNs. Cross-organisational labelled time workflow nets (CLTWNs) is then defined based on LTWNs. Third, the article proposes the notion of OR-silent CLTWNS and a verifying approach to the soundness of LTWNs and CLTWNs. Finally, this article illustrates how to use the proposed method by a simple example. The purpose of this research is to establish a formal method of modelling and analysis of workflow systems for LSC. This study initiates a new perspective of research on cross-organisational workflow management and promotes operation management of LSC in real world settings.

  3. Why not to choose the most convenient labor supply model? The impact of labor supply modeling on policy evaluation

    OpenAIRE

    Hirte, Georg; Tscharaktschiew, Stefan

    2015-01-01

    The public economics, environmental, transportation and urban economics literature applies different labor supply approaches when studying economic or planning instruments. Some studies assume that working hours are endogenous while the number of workdays is given, whereas others model only decisions on workdays. Unfortunately, empirical evidence does hardly exist on account of missing data. Against this background, we provide an assessment of whether general effects of those policies are rob...

  4. Levels & Barriers to Supply Chain Integration: A conceptual model of Supply Chain Performance

    OpenAIRE

    RajaIrfan Sabir; Muhammad Irfan

    2014-01-01

    In modern business scenario Supply chain has become the back bone for every business organization. All supply chain partners are joined together in value delivery network of company that no one can perform better without support of other. The ultimate objective of this cohesive relationship is to deliver value to customers and gets desired state of customer satisfaction & loyalty for the organization. For this purpose it is necessary to integrate the internal and external partners of Supply c...

  5. Hydrocarbon accumulation model of the Cretaceous in southern China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Cretaceous in southern China is mainly a set of red and mauve clastic rock,with evaporation layers. For lack of source rock,it has been paid little attention to in the exploration process. With the development of research on hydrocarbon exploration,the masses of Cretaceous reservoirs and shows have been found in recent years. This means that the Cretaceous has great exploration potential. According to the research,authors find that the high-quality reservoir and efficient cap rocks develop in the Cretaceous. At the same time,the Cretaceous and underlying Paleozoic-Early Mesozoic marine strata and overlying Cenozoic nonmarine strata constitute a superimposed basin. Moreover,high-quality source rocks developed in the above-mentioned two sets of strata. In the south,especially in the middle and lower Yangtze region since the Himalayan strong rift was associated with a large number of faults,These faults connect the Cretaceous reservoir and its overlying and underlying source rocks,forming the fault-based and unconformity-based discontinuous source-reservoir-cap accumulation assemblages. Because the Cretaceous has the abundant oil and gas from Paleogene source rocks or Mesozoic–Paleozoic source rocks with secondary hydrocarbon generation ability,three types of reservoirs develop in the Cretaceous:"new-generating and old-reservoiring" reservoirs,"old-generating andnew-reservoiring" reservoirs,and few "self-generating andself-reservoiring" reservoirs. The hydrocarbon enrichment depends on two key factors. Firstly,Cretaceous reservoirs are near to the source kitchens,so its oil and gas source is ample. Secondly,the fault system is well developed,which provides the necessary conducting systems for hydrocarbon accumulation.

  6. Discrete fracture modeling of multiphase flow and hydrocarbon production in fractured shale or low permeability reservoirs

    Science.gov (United States)

    Hao, Y.; Settgast, R. R.; Fu, P.; Tompson, A. F. B.; Morris, J.; Ryerson, F. J.

    2016-12-01

    It has long been recognized that multiphase flow and transport in fractured porous media is very important for various subsurface applications. Hydrocarbon fluid flow and production from hydraulically fractured shale reservoirs is an important and complicated example of multiphase flow in fractured formations. The combination of horizontal drilling and hydraulic fracturing is able to create extensive fracture networks in low permeability shale rocks, leading to increased formation permeability and enhanced hydrocarbon production. However, unconventional wells experience a much faster production decline than conventional hydrocarbon recovery. Maintaining sustainable and economically viable shale gas/oil production requires additional wells and re-fracturing. Excessive fracturing fluid loss during hydraulic fracturing operations may also drive up operation costs and raise potential environmental concerns. Understanding and modeling processes that contribute to decreasing productivity and fracturing fluid loss represent a critical component for unconventional hydrocarbon recovery analysis. Towards this effort we develop a discrete fracture model (DFM) in GEOS (LLNL multi-physics computational code) to simulate multiphase flow and transfer in hydraulically fractured reservoirs. The DFM model is able to explicitly account for both individual fractures and their surrounding rocks, therefore allowing for an accurate prediction of impacts of fracture-matrix interactions on hydrocarbon production. We apply the DFM model to simulate three-phase (water, oil, and gas) flow behaviors in fractured shale rocks as a result of different hydraulic stimulation scenarios. Numerical results show that multiphase flow behaviors at the fracture-matrix interface play a major role in controlling both hydrocarbon production and fracturing fluid recovery rates. The DFM model developed in this study will be coupled with the existing hydro-fracture model to provide a fully integrated

  7. Spational modeling of a sustainable gas supply chain by matching supply and demand

    NARCIS (Netherlands)

    prof. dr. Wim van Gemert; A.A. Broekhuis; Ir. J. Bekkering

    2012-01-01

    Biogas production from co-digestion of cattle manure and biomass can have a significant contribution to a sustainable gas supply when this gas is upgraded to specifications prescribed for injection into the national gas grid and injected into this grid. In this study we analyzed such a gas supply ch

  8. Sustainable Logistics Network Modeling for Enterprise Supply Chain

    Directory of Open Access Journals (Sweden)

    Lan Zhu

    2017-01-01

    Full Text Available With the expansion of the study about green logistics, sustainable supply chain management (SSCM has appeared as a new concept in current economic circumstance. This paper studies the sustainability optimization of enterprise logistics network from a strategic perspective and proposes a multiobjective sustainable logistics optimization model considering three dimensions of sustainability: economy, environment, and society. In this model, the environment factor was measured with a Life Cycle Assessment (LCA method based on Chinese Life Cycle Database (CLCD, while for social factors, Sustainability Reporting Guidelines (GRI are utilized to quantify the social performance. Moreover, the model was solved with an adapted version of the ε-constraint method named augment constraint algorithm (AUGMENCON through GAMS software. The numerical experiment results of a computer manufacturer supply chain show that the proposed model is able to integrate all dimensions of sustainability and simultaneously prove the capability of AUGMENCON in providing a set of trade-off solutions for the decision makers to make different decisions under different environment and social requirements.

  9. Teaching Supply Chain Management Complexities: A SCOR Model Based Classroom Simulation

    Science.gov (United States)

    Webb, G. Scott; Thomas, Stephanie P.; Liao-Troth, Sara

    2014-01-01

    The SCOR (Supply Chain Operations Reference) Model Supply Chain Classroom Simulation is an in-class experiential learning activity that helps students develop a holistic understanding of the processes and challenges of supply chain management. The simulation has broader learning objectives than other supply chain related activities such as the…

  10. Teaching Supply Chain Management Complexities: A SCOR Model Based Classroom Simulation

    Science.gov (United States)

    Webb, G. Scott; Thomas, Stephanie P.; Liao-Troth, Sara

    2014-01-01

    The SCOR (Supply Chain Operations Reference) Model Supply Chain Classroom Simulation is an in-class experiential learning activity that helps students develop a holistic understanding of the processes and challenges of supply chain management. The simulation has broader learning objectives than other supply chain related activities such as the…

  11. Modelling a flows in supply chain with analytical models: Case of a chemical industry

    Science.gov (United States)

    Benhida, Khalid; Azougagh, Yassine; Elfezazi, Said

    2016-02-01

    This study is interested on the modelling of the logistics flows in a supply chain composed on a production sites and a logistics platform. The contribution of this research is to develop an analytical model (integrated linear programming model), based on a case study of a real company operating in the phosphate field, considering a various constraints in this supply chain to resolve the planning problems for a better decision-making. The objectives of this model is to determine and define the optimal quantities of different products to route, to and from the various entities in the supply chain studied.

  12. An integrated supply chain model for new products with imprecise production and supply under scenario dependent fuzzy random demand

    Science.gov (United States)

    Nagar, Lokesh; Dutta, Pankaj; Jain, Karuna

    2014-05-01

    In the present day business scenario, instant changes in market demand, different source of materials and manufacturing technologies force many companies to change their supply chain planning in order to tackle the real-world uncertainty. The purpose of this paper is to develop a multi-objective two-stage stochastic programming supply chain model that incorporates imprecise production rate and supplier capacity under scenario dependent fuzzy random demand associated with new product supply chains. The objectives are to maximise the supply chain profit, achieve desired service level and minimise financial risk. The proposed model allows simultaneous determination of optimum supply chain design, procurement and production quantities across the different plants, and trade-offs between inventory and transportation modes for both inbound and outbound logistics. Analogous to chance constraints, we have used the possibility measure to quantify the demand uncertainties and the model is solved using fuzzy linear programming approach. An illustration is presented to demonstrate the effectiveness of the proposed model. Sensitivity analysis is performed for maximisation of the supply chain profit with respect to different confidence level of service, risk and possibility measure. It is found that when one considers the service level and risk as robustness measure the variability in profit reduces.

  13. Effective food supply chains; generating, modelling and evaluating supply chain scenarios

    OpenAIRE

    Vorst, van der, J.G.A.J.

    2000-01-01

    Logistical co-ordination in FMCG supply chainsThe overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to find an efficient and effective method to analyse and redesign the SC to improve SC performance.BackgroundThe background and rationale of this thesis are discussed in Chapter 1. Interest in SCM has been spurred by recent socio-e...

  14. Effective food supply chains : generating, modelling and evaluating supply chain scenarios

    OpenAIRE

    Vorst, van de, GAL Alfred

    2000-01-01

    Logistical co-ordination in FMCG supply chains

    The overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to find an efficient and effective method to analyse and redesign the SC to improve SC performance.

    Background

    The background and rationale of this thesis are disc...

  15. Control of facies/potential on hydrocarbon accumulation:a geological model for Iacustrine rift basins

    Institute of Scientific and Technical Information of China (English)

    Chen Dongxia; Pang Xiongqi; Zhang Shanwen; Wang Yongshi; Zhang Jun

    2008-01-01

    The formation and distribution of hydrocarbon accumulations are jointly controlled by"stratigraphic facies"and"fluid potential",which can be abbreviated in"control of facies/potential on hydrocarbon accumulation".Facies and potential control the time-space distribution of hydrocarbon accumulation macroscopically and the petroliferous characteristics of hydrocarbon accumulation microscopically.Tectonic facies and sedimentary facies control the time-space distribution.Lithofacies and petrophysical facies control the petroliferous characteristics.Favorable facies and high porosity and permeability control hydrocarbon accumulation in the lacustrine rift basins in China.Fluid potential is represented by the work required,which comprises the work against gravity,pressure,interfacial energy and kinetic energy.Hydrocarbon migration and accumulation are controlled by the joint action of multiple driving forces,and are characterized by accumulation in the area of low potential.At the structural high,low geopotential energy caused by buoyancy control anticlinal reservoir.The formation of lithological oil pool is controlled by low interfacial energy caused by capillary force.Low compressive energy caused by overpressure and faulting activity control the formation of the faulted block reservoir.Low geopotential energy of the basin margin caused by buoyancy control stratigraphic reservoir.The statistics of a large number of oil reservoirs show that favorable facies and low potential control hydrocarbon accumulation in the rift basin.where over 85% of the discovered hydrocarbon accumulations are distributed in the trap with favorable facies and lOW potentials.The case study showed that the prediction of favorable areas by application of the near source-favorable facies-low potential accumulation model correlated well with over 90% of the discovered oil pools' distribution of the middle section of the third member of the Shahejie Formation in the Dongying Depression,Bohai Bay

  16. Modeling transport effects of perfluorinated and hydrocarbon surfactants in groundwater by using micellar liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Rashad N. [Department of Chemistry and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1322 (United States); McGuffin, Victoria L. [Department of Chemistry and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1322 (United States)], E-mail: jgshabus@aol.com

    2007-11-05

    The effects of hydrocarbon and perfluorinated surfactants, above their critical micelle concentration (CMC), on the transport of neutral environmental pollutants are compared. Reversed-phase micellar liquid chromatography is used to model the groundwater system. The octadecylsilica stationary phase serves to simulate soil particles containing organic matter, whereas the aqueous surfactant mobile phases serve to simulate groundwater containing a surfactant at varying concentrations. Sodium dodecyl sulfate and lithium perfluorooctane sulfonate are used as representatives of the hydrocarbon and perfluorinated surfactants, respectively. Benzene, mono- and perhalogenated benzenes, and polycyclic aromatic hydrocarbons are used as models for environmental pollutants. Transport effects were elucidated from the retention factor, k, and the equilibrium constant per micelle, K{sub eq}, of the model pollutants in the individual surfactants. Based on k values, the transport of the model pollutants increased in both surfactant solutions in comparison to pure water. As the concentration of the surfactants increased, the transport of the pollutants increased as well. Notably, the K{sub eq} values of the pollutants in the perfluorinated surfactant were at least an order of magnitude less than those in the hydrocarbon surfactant. Overall, these results suggest that the presence of a perfluorinated surfactant, above its CMC, increases the transport of pollutants in a groundwater system. However, the perfluorinated surfactant exhibits a lesser transport effect than the hydrocarbon surfactant.

  17. The security of energy infrastructure and supply in North Africa: Hydrocarbons and renewable energies in comparative perspective

    Energy Technology Data Exchange (ETDEWEB)

    Lacher, Wolfram, E-mail: wolfram.lacher@swp-berlin.org [Stiftung Wissenschaft und Politik/German Institute for International and Security Affairs (SWP), Berlin (Germany); Kumetat, Dennis, E-mail: d.kumetat@lse.ac.uk [Department of Geography and Environment, London School of Economics and Political Science, London (United Kingdom)

    2011-08-15

    While security risks to energy infrastructure and supply are frequently cited as a source of concern in the public debate on Europe's energy relationships with North Africa, few academic publications have addressed the issue to date. This article focuses on two potential threats to energy security in the North African context: first, intenational disruption of energy supplies by governments; second, attacks by non-state actors on energy infrastructure. Based on an analysis of North African security and energy geopolitics, the article provides an assessment of these threats as they have materialized with regard to existing energy industries, particularly oil and gas. The article then seeks to apply the findings to renewable energy schemes that are currently being discussed and developed, gauging the likelihood and impact of such threats materializing in respect to various technologies, and differentiating between different states of the region. Finally, the article provides recommendations for policy and further research needs for a successful common European-North African energy future. - Research Highlights: >Interest for investments into renewable energy projects in North Africa is growing. >Perceptions of political/security risks to renewables in North Africa are exaggerated. >Investment in renewables would boost interdependencies between Europe, North Africa. >Terrorist attacks unlikely to pose a major threat to renewables projects in North Africa.

  18. Modelling and genetic algorithm based optimisation of inverse supply chain

    Science.gov (United States)

    Bányai, T.

    2009-04-01

    (Recycling of household appliances with emphasis on reuse options). The purpose of this paper is the presentation of a possible method for avoiding the unnecessary environmental risk and landscape use through unprovoked large supply chain of collection systems of recycling processes. In the first part of the paper the author presents the mathematical model of recycling related collection systems (applied especially for wastes of electric and electronic products) and in the second part of the work a genetic algorithm based optimisation method will be demonstrated, by the aid of which it is possible to determine the optimal structure of the inverse supply chain from the point of view economical, ecological and logistic objective functions. The model of the inverse supply chain is based on a multi-level, hierarchical collection system. In case of this static model it is assumed that technical conditions are permanent. The total costs consist of three parts: total infrastructure costs, total material handling costs and environmental risk costs. The infrastructure-related costs are dependent only on the specific fixed costs and the specific unit costs of the operation points (collection, pre-treatment, treatment, recycling and reuse plants). The costs of warehousing and transportation are represented by the material handling related costs. The most important factors determining the level of environmental risk cost are the number of out of time recycled (treated or reused) products, the number of supply chain objects and the length of transportation routes. The objective function is the minimization of the total cost taking into consideration the constraints. However a lot of research work discussed the design of supply chain [8], but most of them concentrate on linear cost functions. In the case of this model non-linear cost functions were used. The non-linear cost functions and the possible high number of objects of the inverse supply chain leaded to the problem of choosing a

  19. The role of uncertainty in supply chains under dynamic modeling

    Directory of Open Access Journals (Sweden)

    M. Fera

    2017-01-01

    Full Text Available The uncertainty in the supply chains (SCs for manufacturing and services firms is going to be, over the coming decades, more important for the companies that are called to compete in a new globalized economy. Risky situations for manufacturing are considered in trying to individuate the optimal positioning of the order penetration point (OPP. It aims at defining the best level of information of the client’s order going back through the several supply chain (SC phases, i.e. engineering, procurement, production and distribution. This work aims at defining a system dynamics model to assess competitiveness coming from the positioning of the order in different SC locations. A Taguchi analysis has been implemented to create a decision map for identifying possible strategic decisions under different scenarios and with alternatives for order location in the SC levels. Centralized and decentralized strategies for SC integration are discussed. In the model proposed, the location of OPP is influenced by the demand variation, production time, stock-outs and stock amount. Results of this research are as follows: (i customer-oriented strategies are preferable under high volatility of demand, (ii production-focused strategies are suggested when the probability of stock-outs is high, (iii no specific location is preferable if a centralized control architecture is implemented, (iv centralization requires cooperation among partners to achieve the SC optimum point, (v the producer must not prefer the OPP location at the Retailer level when the general strategy is focused on a decentralized approach.

  20. Modelling the hydrocarbon generation and migration in the West Netherlands Basin, the Netherlands

    NARCIS (Netherlands)

    Balen, R.T. van; Bergen, F. van; Leeuw, C. de; Pagnier, H.; Simmelink, H.; Wees, J.D. van; Verweij, J.M.

    2000-01-01

    The hydrocarbon systems of the Mesozoic, inverted West Netherlands Basin have been analyzed using 2-D forward modelling. Three source rocks are considered in the modelling: Lower Jurassic oil-prone shales, Westphalian gas-prone coal deposits, and Lower Namurian oil-prone shales. The Lower Namurian h

  1. Empirical modeling of soot formation in shock-tube pyrolysis of aromatic hydrocarbons

    Science.gov (United States)

    Frenklach, M.; Clary, D. W.; Matula, R. A.

    1986-01-01

    A method for empirical modeling of soot formation during shock-tube pyrolysis of aromatic hydrocarbons is developed. The method is demonstrated using data obtained in pyrolysis of argon-diluted mixtures of toluene behind reflected shock waves. The developed model is in good agreement with experiment.

  2. Uncertainty Categorization, Modeling, and Management for Regional Water Supply Planning

    Science.gov (United States)

    Fletcher, S.; Strzepek, K. M.; AlSaati, A.; Alhassan, A.

    2016-12-01

    Many water planners face increased pressure on water supply systems from growing demands, variability in supply and a changing climate. Short-term variation in water availability and demand; long-term uncertainty in climate, groundwater storage, and sectoral competition for water; and varying stakeholder perspectives on the impacts of water shortages make it difficult to assess the necessity of expensive infrastructure investments. We categorize these uncertainties on two dimensions: whether they are the result of stochastic variation or epistemic uncertainty, and whether the uncertainties can be described probabilistically or are deep uncertainties whose likelihood is unknown. We develop a decision framework that combines simulation for probabilistic uncertainty, sensitivity analysis for deep uncertainty and Bayesian decision analysis for uncertainties that are reduced over time with additional information. We apply this framework to two contrasting case studies - drought preparedness in Melbourne, Australia and fossil groundwater depletion in Riyadh, Saudi Arabia - to assess the impacts of different types of uncertainty on infrastructure decisions. Melbourne's water supply system relies on surface water, which is impacted by natural variation in rainfall, and a market-based system for managing water rights. Our results show that small, flexible investment increases can mitigate shortage risk considerably at reduced cost. Riyadh, by contrast, relies primarily on desalination for municipal use and fossil groundwater for agriculture, and a centralized planner makes allocation decisions. Poor regional groundwater measurement makes it difficult to know when groundwater pumping will become uneconomical, resulting in epistemic uncertainty. However, collecting more data can reduce the uncertainty, suggesting the need for different uncertainty modeling and management strategies in Riyadh than in Melbourne. We will categorize the two systems and propose appropriate

  3. Mathematical Programming Model of Biodiesel Supply Chain in Colombia

    Directory of Open Access Journals (Sweden)

    Johan Alexander Aranda Pinilla

    2014-06-01

    in order to coordinate a structured way fl ow of resources between the links in the chain starting with “harvesting” going through the middle steps of “extraction” and “conversion” until the fi nal step “mixture “, which are involved in the supply network. The goal of the model is to determine a distribution plan of palm, oil, biodiesel and diesel throughout the chain, along with a production and inventory plan, and a capacity increase plan for biorefi neries in a way that minimizes the total cost of the production chain over a predefi ned planning horizon. The application of the model results in a projection to the year 2043 showing the behavior of the chain, specifi cally soil requirements for such production levels.

  4. Modeling and analyzing a health care supply chain system

    OpenAIRE

    Al-Thumairi, Ahmed Hamad

    2006-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. A Thesis presented on Improving and Redefining the Supply Chain in Healthcare, defining existing problems with current Supply Chain applications, and reviewing current applications and trends in the Supply Chain culture within the Manufacturing Industries and Healthcare Industries. Research of successful applications of new, and improvements to existing supply chain methodologies are prese...

  5. Model-Based Engineering for Supply Chain Risk Management

    Science.gov (United States)

    2015-09-30

    units in a sourced product and implement practical measures for their management and assurance throughout the acquisition life cycle. Supply Chain ...open source More importantly COTS products are typically integrated up a sourced supply chain , which creates a problem of security assurance and...components from many sources . Problem Statement: The Weakest Link Typically, supply chains are hierarchical, with the primary supplier forming the

  6. A Modified Deterministic Model for Reverse Supply Chain in Manufacturing

    Directory of Open Access Journals (Sweden)

    R. N. Mahapatra

    2013-01-01

    Full Text Available Technology is becoming pervasive across all facets of our lives today. Technology innovation leading to development of new products and enhancement of features in existing products is happening at a faster pace than ever. It is becoming difficult for the customers to keep up with the deluge of new technology. This trend has resulted in gross increase in use of new materials and decreased customers' interest in relatively older products. This paper deals with a novel model in which the stationary demand is fulfilled by remanufactured products along with newly manufactured products. The current model is based on the assumption that the returned items from the customers can be remanufactured at a fixed rate. The remanufactured products are assumed to be as good as the new ones in terms of features, quality, and worth. A methodology is used for the calculation of optimum level for the newly manufactured items and the optimum level of the remanufactured products simultaneously. The model is formulated depending on the relationship between different parameters. An interpretive-modelling-based approach has been employed to model the reverse logistics variables typically found in supply chains (SCs. For simplicity of calculation a deterministic approach is implemented for the proposed model.

  7. Consequence and Resilience Modeling for Chemical Supply Chains

    Science.gov (United States)

    Stamber, Kevin L.; Vugrin, Eric D.; Ehlen, Mark A.; Sun, Amy C.; Warren, Drake E.; Welk, Margaret E.

    2011-01-01

    The U.S. chemical sector produces more than 70,000 chemicals that are essential material inputs to critical infrastructure systems, such as the energy, public health, and food and agriculture sectors. Disruptions to the chemical sector can potentially cascade to other dependent sectors, resulting in serious national consequences. To address this concern, the U.S. Department of Homeland Security (DHS) tasked Sandia National Laboratories to develop a predictive consequence modeling and simulation capability for global chemical supply chains. This paper describes that capability , which includes a dynamic supply chain simulation platform called N_ABLE(tm). The paper also presents results from a case study that simulates the consequences of a Gulf Coast hurricane on selected segments of the U.S. chemical sector. The case study identified consequences that include impacted chemical facilities, cascading impacts to other parts of the chemical sector. and estimates of the lengths of chemical shortages and recovery . Overall. these simulation results can DHS prepare for and respond to actual disruptions.

  8. Maturity Models in Supply Chain Sustainability: A Systematic Literature Review

    Directory of Open Access Journals (Sweden)

    Elisabete Correia

    2017-01-01

    Full Text Available A systematic literature review of supply chain maturity models with sustainability concerns is presented. The objective is to give insights into methodological issues related to maturity models, namely the research objectives; the research methods used to develop, validate and test them; the scope; and the main characteristics associated with their design. The literature review was performed based on journal articles and conference papers from 2000 to 2015 using the SCOPUS, Emerald Insight, EBSCO and Web of Science databases. Most of the analysed papers have as main objective the development of maturity models and their validation. The case study is the methodology that is most widely used by researchers to develop and validate maturity models. From the sustainability perspective, the scope of the analysed maturity models is the Triple Bottom Line (TBL and environmental dimension, focusing on a specific process (eco-design and new product development and without a broad SC perspective. The dominant characteristics associated with the design of the maturity models are the maturity grids and a continuous representation. In addition, results do not allow identifying a trend for a specific number of maturity levels. The comprehensive review, analysis, and synthesis of the maturity model literature represent an important contribution to the organization of this research area, making possible to clarify some confusion that exists about concepts, approaches and components of maturity models in sustainability. Various aspects associated with the maturity models (i.e., research objectives, research methods, scope and characteristics of the design of models are explored to contribute to the evolution and significance of this multidimensional area.

  9. A VMI Model in Supplier-Driven Supply Chain and Its Performance Simulation

    National Research Council Canada - National Science Library

    Qiuzheng Li

    2010-01-01

    This research builds a VMI inventory decision model of supplier-driver supply chain to analyze the effects of VMI on a supply chain performance and announce the important function of VMI in promoting...

  10. Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

    Science.gov (United States)

    Smith, Matthew R; Micha, Renata; Golden, Christopher D; Mozaffarian, Dariush; Myers, Samuel S

    2016-01-01

    Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS) model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent

  11. Global Expanded Nutrient Supply (GENuS Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

    Directory of Open Access Journals (Sweden)

    Matthew R Smith

    Full Text Available Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1 data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2 household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against

  12. Adapting transport modes to supply chains classified by the uncertainty supply chain model: A case study at Manaus Industrial Pole

    Directory of Open Access Journals (Sweden)

    Fabiana Lucena Oliveira

    2017-01-01

    Full Text Available This paper discusses transport modes supporting Uncertainty Supply Chain Model (USCM in the case of Manaus Industrial Pole (PIM, an industrial cluster in the Brazilian Amazon that hosts six hundred factories with diverse logistics and supply chain managerial strategies. USCM (Lee, 2002; Fisher, 1997develops a dot matrix classification of the supply chains considering several attributes (e.g., agility, cost, security, responsiveness and argues that emergent economies industrial clusters, in the effort to keep attractiveness for technological frontier firms, need to adapt supply chain strategies according to USCM attributes. The paper takes a further step, discussing which transport modes are suitable to each supply chain classified at the USCM in PIM´s case. The research´s methods covered the use of PIM´s statistical official database (secondary data, interviews with the main logistical services providers of PIM and phone survey with a sample of firms (primary data. Findings confirm the theoretical argument that different supply chains will demand different transport modes running at the same time in the same industrial cluster (Oliveira, 2009. In the case of PIM, this implies investments on port and airport infrastructure and a strategic focus on air transport mode, due to (1 short life cycle of products, (2 distance from suppliers, (3 quick response to demand and (4 the fact that even PIM´s standard products use, in average, forty per cent of air transport at inbound logistics.

  13. Modeling integrated water user decisions in intermittent supply systems

    Science.gov (United States)

    Rosenberg, David E.; Tarawneh, Tarek; Abdel-Khaleq, Rania; Lund, Jay R.

    2007-07-01

    We apply systems analysis to estimate household water use in an intermittent supply system considering numerous interdependent water user behaviors. Some 39 household actions include conservation; improving local storage or water quality; and accessing sources having variable costs, availabilities, reliabilities, and qualities. A stochastic optimization program with recourse decisions identifies the infrastructure investments and short-term coping actions a customer can adopt to cost-effectively respond to a probability distribution of piped water availability. Monte Carlo simulations show effects for a population of customers. Model calibration reproduces the distribution of billed residential water use in Amman, Jordan. Parametric analyses suggest economic and demand responses to increased availability and alternative pricing. It also suggests potential market penetration for conservation actions, associated water savings, and subsidies to entice further adoption. We discuss new insights to size, target, and finance conservation.

  14. Equation of state density models for hydrocarbons in ultradeep reservoirs at extreme temperature and pressure conditions

    Science.gov (United States)

    Wu, Yue; Bamgbade, Babatunde A.; Burgess, Ward A.; Tapriyal, Deepak; Baled, Hseen O.; Enick, Robert M.; McHugh, Mark A.

    2013-10-01

    The necessity of exploring ultradeep reservoirs requires the accurate prediction of hydrocarbon density data at extreme temperatures and pressures. In this study, three equations of state (EoS) models, Peng-Robinson (PR), high-temperature high-pressure volume-translated PR (HTHP VT-PR), and perturbed-chain statistical associating fluid theory (PC-SAFT) EoS are used to predict the density data for hydrocarbons in ultradeep reservoirs at temperatures to 523 K and pressures to 275 MPa. The calculated values are compared with experimental data. The results show that the HTHP VT-PR EoS and PC-SAFT EoS always perform better than the regular PR EoS for all the investigated hydrocarbons.

  15. Utilization of biomass: Conversion of model compounds to hydrocarbons over zeolite H-ZSM-5

    DEFF Research Database (Denmark)

    Mentzel, Uffe Vie; Holm, Martin Spangsberg

    2011-01-01

    Zeolite catalyzed deoxygenation of small oxygenates present in bio-oil or selected as model compounds was performed under Methanol-to-Hydrocarbons (MTH) like reaction conditions using H-ZSM-5 as the catalyst. Co-feeding of the oxygenates with methanol generally decreases catalyst lifetime due to ...

  16. Study on Modeling and Simulation of Reliability Diagnosis of Supply Chain Based on Common Cause Failure

    Directory of Open Access Journals (Sweden)

    Guohua Chen

    2013-01-01

    Full Text Available To diagnose key factors which cause the failure of supply chain, on the base of taking 3-tier supply chain centering on manufacturer as the object, the diagnostic model of reliability of supply chain with common cause failure was established. Then considering unreliability and key importance as quantitative index, the diagnostic algorism of key factors of reliability of supply chain with common cause failure was studied by the method of Monte Carlo Simulation. The algorism can be used to evaluate the reliability of f supply chain and determine key factors which cause the failure of supply chain, which supplies a new method for diagnosing reliability of supply chain based on common cause failure. Finally, an example was presented to prove the feasibility and validity of the model and method.

  17. Supply Chain Modeling: Downstream Risk Assessment Methodology (DRAM) Demonstration of Capability

    Science.gov (United States)

    2015-04-01

    This work was done for Defense Logistics Agency Strategic Materials (DLA SM) to provide the capability to analyze supply chains of strategic and...of Defense for Acquisition, Technology and Logistics , 2013). 9 3. Supply Chain Modeling... Logistics , 2013. Kouvelis, Panos, Lingxiu Dong, Onur Boyabatli, and Rong Li. Handbook of Integrated Risk Management in Global Supply Chains Hoboken, NJ

  18. Designing Leadership models in a Three Level Unlimited Supply Chain: Non-Cooperative Game Theory Approach

    Directory of Open Access Journals (Sweden)

    Ahmad Jaafarnehad

    2015-09-01

    Full Text Available The role and importance of supply chain management, has faced with many challenges and problems. Although a comprehensive model of supply chain issues, has not been explained, we have to indicate that issues such as reviewing the theoretical foundations of information systems, marketing, financial management, logistical and organizational relations have been considered by many researchers. The objective of supply chain management is to improve various activities and components to increase overall supply chain system benefits. In order to achieve the overall objectives, many contradictions may occur between the components and different levels of supply chain and the contradictions that these disorders over time, result in decreased strength and competitiveness of the supply chain. Such conflicts, like marketing costs (advertising, pricing and inventory can occur during the supply chain life cycle. A Game Theory approach with respect to property is the appropriate tool for collaboration in the supply chain. This tool is used for collaborative making in any kind of supply chain such as cooperative supply chain and non-cooperative supply chain. In the present study and assuming a lack of cooperation between different levels of a supply chain, a dynamic game with complete information has been generated. In addition identifying appropriate leaders of various levels of the supply chain is considered. Non-Cooperative dynamic game mode (Stackelberg Game, for each of the three levels of supply chain including retailers, suppliers and manufacturers are modeled. Depending on the bargaining power and its position in the market, any level of supply chain can make a leader of the following rule. In the present study, the equilibrium model to play Stackelberg game may be led by a leader or leading players and ultimately identifying and modeling the appropriate unlimited three level supply chain are determined.

  19. Research on Knowledge-Oriented Supply ChainRisk Management System Model

    OpenAIRE

    Yingchun Guo

    2011-01-01

    Based on analyzing the characteristics of supply chain risk management under the influences of knowledge, in this paper integrates basic theories and methods of knowledge management into the process of risk management, builds a knowledge-oriented supply chain risk management system model, and proposes relevant strategies, presenting references for practical application of knowledge-oriented supply chain risk management. By means of acquiring, storing, sharing, and transferring supply chain ri...

  20. The Predictive Value of Subjective Labour Supply Data: A Dynamic Panel Data Model with Measurement Error

    OpenAIRE

    Euwals, Rob

    2002-01-01

    This paper tests the predictive value of subjective labour supply data for adjustments in working hours over time. The idea is that if subjective labour supply data help to predict next year?s working hours, such data must contain at least some information on individual labour supply preferences. This informational content can be crucial to identify models of labour supply. Furthermore, it can be crucial to investigate the need for, or, alternatively, the support for laws and collective agree...

  1. Operational modeling of a sustainable gas supply chain

    NARCIS (Netherlands)

    Bekkering, Jan; Broekhuis, Ton A; van Gemert, Wim J. T.

    2010-01-01

    Biogas production from codigestion of cattle manure and biomass can have a significant contribution to a sustainable gas supply when this gas is upgraded to specifications prescribed for injection into the national gas grid and injected into this grid. In this study, we analyzed such a gas supply ch

  2. Operational modeling of a sustainable gas supply chain

    NARCIS (Netherlands)

    Bekkering, Jan; Broekhuis, Ton A; van Gemert, Wim J. T.

    2010-01-01

    Biogas production from codigestion of cattle manure and biomass can have a significant contribution to a sustainable gas supply when this gas is upgraded to specifications prescribed for injection into the national gas grid and injected into this grid. In this study, we analyzed such a gas supply

  3. Mathematical modelling on transport of petroleum hydrocarbons in saturated fractured rocks

    Indian Academy of Sciences (India)

    G Suresh Kumar

    2014-10-01

    The present paper addresses critical issues that describe the dissolution mass transfer of petroleum hydrocarbons in a saturated subsurface system. The field procedure associated with the estimation of Light Non-Aqueous Phase Liquid (LNAPL) thickness in site monitor wells is revisited. A brief theory has been included on the composition and transport of petroleum hydrocarbons following an onshore oil spill in order to demonstrate the level of complexity associated with the LNAPL dissolution mass transfer even in a classical porous medium. However, such studies in saturated fractured rocks are highly complex and limited, and hence, deserve a special attention as the fate and transport of the petroleum hydrocarbons are not uncommon in saturated fractured rocks. In this context, an improved mathematical model has been proposed that will better describe the dissolution kinetics of petroleum hydrocarbons in saturated fractured rocks at the scale of a single fracture using dual-porosity concept. The lumped mass transfer coefficient in a classical porous medium proposed depends on mean grain size, while the same parameter has been replaced by an equivalent average thickness of fracture aperture that better describes the LNAPL dissolution rate in a coupled fracture-matrix system. A set of nonlinear coupled partial differential equations is deduced for a coupled fracture-matrix system in analogy with the differential equations of a classical porous medium. The proposed mathematical model may work well for the fracture aperture thicknesses varying between 100 and 500 microns with a relatively low Reynolds Number and initial NAPL saturation.

  4. Generalized Pareto Distribution Model and Its Application to Hydrocarbon Resource Structure Prediction of the Huanghua Depression

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The generalized Pareto distribution model is a kind of hydrocarbon pool size probability statistical method for resource assessment. By introducing the time variable, resource conversion rate and the geological variable, resource density, such model can describe not only different types of basins, but also any exploration samples at different phases of exploration, up to the parent population. It is a dynamic distribution model with profound geological significance and wide applicability. Its basic principle and the process of resource assessment are described in this paper. The petroleum accumulation system is an appropriate assessment unit for such method. The hydrocarbon resource structure of the Huanghua Depression in Bohai Bay Basin was predicted by using this model. The prediction results accord with the knowledge of exploration in the Huanghua Depression, and point out the remaining resources potential and structure of different petroleum accumulation systems, which are of great significance for guiding future exploration in the Huanghua Depression.

  5. Hydrocarbon Fuel Thermal Performance Modeling based on Systematic Measurement and Comprehensive Chromatographic Analysis

    Science.gov (United States)

    2016-07-27

    Conference Paper 3. DATES COVERED (From - To) 10 June 2016 - 27 July 2016 4. TITLE AND SUBTITLE Hydrocarbon Fuel Thermal Performance Modeling based on...The Johns Hopkins University Energetics Research Group (JHU/ERG), Columbia, MD and University of Washington, Seattle, WA 14. ABSTRACT Ensuring fuel ...is a common requirement for aircraft, rockets, and hypersonic vehicles. The Aerospace Fuels Quality Test and Model Development (AFQTMoDev) project

  6. Prediction of vapor-liquid equilibriafor hydrocarbon binary systems by regular solution model

    OpenAIRE

    下山, 裕介; 米澤, 節子; 小渕, 茂寿; 福地, 賢治; 荒井, 康彦; Shimoyama, Yusuke; Yonezawa, Setsuko; Kobuchi, Shigetoshi; Fukuchi, Kenii; Arai, Yasuhiko

    2007-01-01

    Vapor-liquid equilibria (VLE) of hydrocarbon binary systems : hexane + benzene (25 °C), toluene + octane (60°C) and cyclohexane + toluene (50°C) were predicted by using a regular solution model. In the present model, the mixing entropy term (Flory-Huggins equation) is included and an interaction parameter between unlike molecules is introduced. Solubility parameters and molar volumes at each temperature required in calculation are estimated by previously proposed methods. VLE of hexane + benz...

  7. Energy Supply Modelling in Cities, Illustrated Using Data from the Municipality of Sønderborg in Denmark

    DEFF Research Database (Denmark)

    Sveinbjörnsson, Dadi Þorsteinn; Algren, Loui; Bavnhøj Hansen, Anders;

    developed and modeled different scenarios for Sønderborg’s energy system in 2029, containing various different energy conversion pathways. These include e.g. biogas production and upgrade using hydrogen from electrolysis, scenarios with biomass gasification and local transport fuel production and scenarios...... be enhanced by supplying surplus process heat to the district-heating network and by using electrolysis to produce hydrogen for upgrading of biomass-derived gases. The results also pinpoint the importance of prioritizing biomass for the production of synthetic hydrocarbon transport fuels rather than for heat...... in which gas turbines for reserve electricity generation have been displaced by reversible electrolysis/fuel cell systems. The aim of the case study was to identify if and how new energy conversion technologies can be integrated in the future energy system to meet the demand for energy services...

  8. Modeling Supply Chain Performance: A Structural Equation Approach

    OpenAIRE

    Rajwinder Singh; Sandhu, H.S.; B.A. Metri; Rajinder Kaur

    2013-01-01

    Supply chain management (SCM) has become an effective tool now a day to survive in this competitive world. Organizations do their best to improve performance by adopting better supply chain (SC) performance indicators. In this paper 19 key performance indicators (KPI) were identified based on strong literature support in consultation of practitioners and consultants in the field of non-livestock retailing (NLR). NLR is the retailing of agriculture and horticulture products. The technique of f...

  9. Noble gases solubility models of hydrocarbon charge mechanism in the Sleipner Vest gas field

    Science.gov (United States)

    Barry, P. H.; Lawson, M.; Meurer, W. P.; Warr, O.; Mabry, J. C.; Byrne, D. J.; Ballentine, C. J.

    2016-12-01

    -water exchange (i.e., volumetric gas-water ratios). These data are discussed within the framework of several conceptual models: (i) total gas-stripping model, which assumes all noble gases have been stripped from the water phase, thus defining the minimum volume of water to have interacted with the hydrocarbon phase; (ii) equilibrium model, which assumes equilibration between groundwater and hydrocarbon phase at reservoir P, T and salinity; and (iii) open and closed system gas-stripping models, using concentrations and elemental ratios. By applying these models to Ne-Ar data from Sleipner, we estimate volumetric gas-water ratios (Vg/Vw) between 0.02 and 0.07, which are lower than standard geologic gas-water estimates of ∼0.24, estimated by combining gas-in-place estimates with groundwater porosity estimates. Sleipner Vest data can be best approximated by an open system model, which predicts more than an order of magnitude more groundwater interaction during migration than geologic estimates, indicating a dynamic aquifer system and/or a hydrous migration pathway. In an open system, the extent of gas loss can be estimated to be between 8 and 10 reservoir volumes, which have passed through the system and been lost (i.e., filled and spilled).

  10. An Investigation of Model Catalyzed Hydrocarbon Formation Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Tysoe, W. T.

    2001-05-02

    Work was focused on two areas aimed at understanding the chemistry of realistic catalytic systems: (1) The synthesis and characterization of model supported olefin metathesis catalysts. (2) Understanding the role of the carbonaceous layer present on Pd(111) single crystal model catalysts during reaction.

  11. Hydrocarbons Heterogeneous Pyrolysis: Experiments and Modeling for Scramjet Thermal Management

    CERN Document Server

    Bouchez, Marc; Visez, Nicolas; Herbinet, Olivier; Fournet, René; Marquaire, Paul-Marie

    2009-01-01

    The last years saw a renewal of interest for hypersonic research in general and regenerative cooling specifically, with a large increase of the number of dedicated facilities and technical studies. In order to quantify the heat transfer in the cooled structures and the composition of the cracked fuel entering the combustor, an accurate model of the thermal decomposition of the fuel is required. This model should be able to predict the fuel chemical composition and physical properties for a broad range of pressures, temperatures and cooling geometries. For this purpose, an experimental and modeling study of the thermal decomposition of generic molecules (long-chain or polycyclic alkanes) that could be good surrogates of real fuels, has been started at the DCPR laboratory located in Nancy (France). This successful effort leads to several versions of a complete kinetic model. These models do not assume any effect from the material that constitutes the cooling channel. A specific experimental study was performed ...

  12. Hydrocarbon pneumonia

    Science.gov (United States)

    Pneumonia - hydrocarbon ... Coughing Fever Shortness of breath Smell of a hydrocarbon product on the breath Stupor (decreased level of ... Most children who drink or inhale hydrocarbon products and develop ... hydrocarbons may lead to rapid respiratory failure and death.

  13. Supply Chain Modeling for Fluorspar and Hydrofluoric Acid and Implications for Further Analyses

    Science.gov (United States)

    2015-04-01

    analysis. 15. SUBJECT TERMS supply chain , model, fluorspar, hydrofluoric acid, shortfall, substitution, Defense Logistics Agency, National Defense...unlimited. IDA Document D-5379 Log: H 15-000099 INSTITUTE FOR DEFENSE ANALYSES 4850 Mark Center Drive Alexandria, Virginia 22311-1882 Supply Chain ...E F E N S E A N A L Y S E S IDA Document D-5379 D. Sean Barnett Jerome Bracken Supply Chain Modeling for Fluorspar and Hydrofluoric Acid and

  14. A coordination theoretic model for three level supply chains using contracts

    Indian Academy of Sciences (India)

    Arshinder; Arun Kanda; S G Deshmukh

    2009-10-01

    Typically, supply chain members are dependent on each other to manage various resources and information. The conflicting objectives and lack of coordination between supply chain members may often cause uncertainties in supply and demand. The basic elements of coordination theory like interdependency, coherency and mutuality may help in effective flow of information and material between the dependent supply chain members. Supply chain contract can be an effective coordination mechanism to motivate all the members to be a part of the entire supply chain. There are different types of supply chain contracts such as buy back and quantity flexibility contracts. Supply chain performance may be substantially improved by properly designing the contracts to share risks and rewards. The objective of this paper is to explore the applicability of coordination elements through an analytical model in three-level (Manufacturer–distributor–retailer) serial supply chains using contracts. The model evaluates the impact of supply chain contracts on various performance measures. The impact of some contract may be on some specific performance measure only, which helps managers to choose the type of contract if there is an objective of improving certain performance measure before hand. In three-level supply chains, the contracts are designed at two distinct interfaces: Manufacturer–distributor and distributor–retailer. The model demonstrates the complexity in evaluating the decision variables of three level supply chains. The proposed model is a novel approach to apply coordination theory at various levels of supply chain. The model also presents how the coordination elements are related to each other in various coordination cases.

  15. The Timber Resource Inventory Model (TRIM): a projection model for timber supply and policy analysis.

    Science.gov (United States)

    P.L. Tedder; R.N. La Mont; J.C. Kincaid

    1987-01-01

    TRIM (Timber Resource Inventory Model) is a yield table projection system developed for timber supply projections and policy analysis. TRIM simulates timber growth, inventories, management and area changes, and removals over the projection period. Programs in the TRIM system, card-by-card descriptions of required inputs, table formats, and sample results are presented...

  16. Modeling Integrated Water-User Decisions with Intermittent Supplies

    Science.gov (United States)

    Lund, J. R.; Rosenberg, D.

    2006-12-01

    We present an economic-engineering method to estimate urban water use demands with intermittent water supplies. A two-stage, probabilistic optimization formulation includes a wide variety of water supply enhancement and conservation actions that individual households can adopt to meet multiple water quality uses with uncertain water availability. We embed the optimization in Monte-Carlo simulations to show aggregate effects at a utility (citywide) scale for a population of user conditions and decisions. Parametric analysis provides derivations of supply curves to subsidize conservation, demand responses to alternative pricing, and customer willingness-to-pay to avoid shortages. Results show a good empirical fit for the average and distribution of billed residential water use in Amman, Jordan. Additional outputs give likely market penetration rates for household conservation actions, associated water savings, and subsidies required to entice further adoption. We discuss new insights to size, target, market, and finance conservation programs and interpret a demand curve with block pricing.

  17. Modelling for decision support in the vegetable and fruit supply chain

    NARCIS (Netherlands)

    Top, J.L.; Rijgersberg, H.

    2003-01-01

    Quality modelling in agri-supply chains has become increasingly popular in R&D environments, because of the availability of large amounts of experimental data and mathematical models. At the same time, in industrial supply chains a strong need exists for support in making complex decisions with

  18. Modelling supply networks and business cycles as unstable transport phenomena

    Science.gov (United States)

    Helbing, Dirk

    2003-07-01

    Physical concepts developed to describe instabilities in traffic flows can be generalized in a way that allows one to understand the well-known instability of supply chains (the so-called 'bull-whip effect'). That is, small variations in the consumption rate can cause large variations in the production rate of companies generating the requested product. Interestingly, the resulting oscillations have characteristic frequencies which are considerably lower than the variations in the consumption rate. This suggests that instabilities of supply chains may be the reason for the existence of business cycles. At the same time, we establish some links to queueing theory and between micro- and macroeconomics.

  19. A Review of the Wood Pellet Value Chain, Modern Value/Supply Chain Management Approaches, and Value/Supply Chain Models

    Directory of Open Access Journals (Sweden)

    Natalie M. Hughes

    2014-01-01

    Full Text Available We reviewed 153 peer-reviewed sources to provide identification of modern supply chain management techniques and exploration of supply chain modeling, to offer decision support to managers. Ultimately, the review is intended to assist member-companies of supply chains, mainly producers, improve their current management approaches, by directing them to studies that may be suitable for direct application to their supply chains and value chains for improved efficiency and profitability. We found that information on supply chain management and modeling techniques in general is available. However, few Canadian-based published studies exist regarding a demand-driven modeling approach to value/supply chain management for wood pellet production. Only three papers were found specifically on wood pellet value chain analysis. We propose that more studies should be carried out on the value chain of wood pellet manufacturing, as well as demand-driven management and modeling approaches with improved demand forecasting methods.

  20. A Data Mining Approach to Modelling of Water Supply Assets

    DEFF Research Database (Denmark)

    Babovic, V.; Drecourt, J.; Keijzer, M.

    2002-01-01

    supply assets are mainly situated underground, and therefore not visible and under the influence of various highly unpredictable forces. This paper proposes the use of advanced data mining methods in order to determine the risks of pipe bursts. For example, analysis of the database of already occurred...

  1. What Hybrid Business Models can Teach Sustainable Supply Chain Management

    DEFF Research Database (Denmark)

    Bals, Lydia; Tate, Wendy L.

    2017-01-01

    businesses in catastrophe-ridden Haiti were performed. The insights provided by the entrepreneurs of these businesses showed organizations that target TBL objectives from their inception, the specific social capabilities employed to obtain the desired TBL objectives and the specific supply chain structures...

  2. A control model for object virtualization in supply chain management

    NARCIS (Netherlands)

    Verdouw, C.N.; Beulens, A.J.M.; Reijers, H.A.; Vorst, van der J.G.A.J.

    2015-01-01

    Due to the emergence of the Internet of Things, supply chain control can increasingly be based on virtual objects instead of on the direct observation of physical objects. Object virtualization allows the decoupling of control activities from the handling and observing of physical products and resou

  3. Mathematical modeling of floating stock policy in FMCG supply chains

    NARCIS (Netherlands)

    M. Pourakbar (Morteza); A.V. Sleptchenko (Andrei); R. Dekker (Rommert)

    2007-01-01

    textabstractThe floating stock distribution concept exploits inter-modal transport to deploy inventories in a supply chain in advance of retailer demand. It is appropriate in case of batch production and containerized transport of standard product mixes. In this way response times are reduced and st

  4. ECONOMETRIC MODELING OF THE DYNAMICS OF VOLUMES HYDROCARBONS OF SMALL OIL AND GAS ENTERPRISES

    Directory of Open Access Journals (Sweden)

    GORLOV A.V.

    2015-01-01

    Full Text Available In this paper investigates the principles of functioning of small oil and gas enterprises of Russia. The basic characteristics and socio-economic tasks performed by the small oil and gas enterprises. Made correlation and regression analysis, a result of which the pair correlation coefficients between the indicator of development of small oil and gas enterprises (volumes hydrocarbons and the factors that characterize the work environment of their operation; built regressions, describing the process of development of small oil and gas enterprises. With a view to forecasting the development of small oil and gas enterprises built production function of Cobb-Douglas and selected econometric model, has good predictive properties. Made predictive calculations dynamics of volumes hydrocarbons of small oil and gas enterprises on formulating scenarios for the planning period (2015-2016 years.

  5. A Collaborative Scheduling Model for the Supply-Hub with Multiple Suppliers and Multiple Manufacturers

    Directory of Open Access Journals (Sweden)

    Guo Li

    2014-01-01

    Full Text Available This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment.

  6. Establishment of Grain Farmers' Supply Response Model and Empirical Analysis under Minimum Grain Purchase Price Policy

    OpenAIRE

    Zhang, Shuang

    2012-01-01

    Based on farmers' supply behavior theory and price expectations theory, this paper establishes grain farmers' supply response model of two major grain varieties (early indica rice and mixed wheat) in the major producing areas, to test whether the minimum grain purchase price policy can have price-oriented effect on grain production and supply in the major producing areas. Empirical analysis shows that the minimum purchase price published annually by the government has significant positive imp...

  7. A robust optimization model for blood supply chain in emergency situations

    OpenAIRE

    Meysam Fereiduni; Kamran Shahanaghi

    2016-01-01

    In this paper, a multi-period model for blood supply chain in emergency situation is presented to optimize decisions related to locate blood facilities and distribute blood products after natural disasters. In disastrous situations, uncertainty is an inseparable part of humanitarian logistics and blood supply chain as well. This paper proposes a robust network to capture the uncertain nature of blood supply chain during and after disasters. This study considers donor points, blood facilities,...

  8. Business process modelling in demand-driven agri-food supply chains : a reference framework

    NARCIS (Netherlands)

    Verdouw, C.N.

    2010-01-01

    Keywords: Business process models; Supply chain management; Information systems; Reference information models; Market orientation; Mass customisation; Configuration; Coordination; Control; SCOR; Pot plants; Fruit industry Abstract The increasing volatility and diversity of demand urge agri-food

  9. Sensitivity of ozone predictions to biogenic hydrocarbon chemistry and emissions in air quality models

    Energy Technology Data Exchange (ETDEWEB)

    Jang, C.J.; Lo, S.C.Y.; Vukovich, J.; Kasibhatla, P. [MCNC-North Carolina Supercomputing Center, Research Triangle Park, NC (United States)

    1997-12-31

    Over the last decade, there is growing evidence that biogenic hydrocarbons play an important role in regional and urban ozone (O{sub 3}) formation in the United States. As a result, the regulatory guidelines issued by the USEPA require that biogenic emissions be included in photochemical modeling. Significant changes and improvement have also been made for estimating the emissions and chemical reaction rates of biogenic hydrocarbons in air quality models. In this paper the authors examine the sensitivity of ozone predictions to the changes in biogenic hydrocarbon chemistry and emissions and investigate why ozone is sensitive to these changes. They first use a Lagrangian box model, the OZIPR/EKMA model, to examine the differences of O{sub 3} predicted using two sets of chemical mechanisms, the original CB4 mechanism and the updated CB4 mechanism with new isoprene chemistry under various emission scenarios. The results show that in the selected urban case, the updated CB4 mechanism predicted lower O{sub 3} than the original CB4 mechanism because of the lower isoprene incremental reactivity in the updated CB4 mechanism. However, in the selected rural case, the updated CB4 mechanism predicted higher O{sub 3} than the original CB4, which is in contradiction to a recent OTAG study using the updated CB4 mechanism. The Eulerian grid model simulation using the MCNC`s EDSS/MAQSIP system further lends support to the box model results. The grid model simulations show that the updated CB4 mechanism predicts much lower O{sub 3} than the original CB4 mechanism over the areas where significant amount of NO{sub x} is emitted; on the contrary, over the Southeastern US region with high isoprene emission rates, the updated CB4 mechanism predicts much higher O{sub 3}.

  10. Study on the Dynamic Pricing Revenue Distribution Model of Fresh Agricultural Products Supply Chain

    Directory of Open Access Journals (Sweden)

    Haoran Shi

    2013-12-01

    Full Text Available This study divides the sales cycle of fresh agricultural products into two stages according to the features of fresh agricultural products, establishes two pricing strategies according to its sales and through constructing an centralized-control model of supply chain under the constraints of revenue sharing contract and through analyzing different prices in the two stages, it summarizes the sales strategies of retailers and supplier and the anticipated sales, proposes to coordinate the operation of fresh agricultural products supply chain by adjusting the revenue coefficient in the revenue sharing contract. After comparing the revenue of decentralized-control supply chain model and centralized-control supply chain model, this study concludes that centralized-control supply chain model will have higher revenue.

  11. SUPPLY CHAIN PERFORMANCE MEASUREMENT: A CASE STUDY ABOUT APPLICABILITY OF SCOR MODEL IN A MANUFACTURING INDUSTRY FIRM

    OpenAIRE

    ERKAN, Turan Erman; BAÇ, Ugur

    2011-01-01

    The Supply Chain Operations Reference model (SCOR) is the product of the Supply Chain Council. The supply chain operations reference model (SCOR) is a management tool used to address, improve, and communicate supply chain management decisions within a company and with suppliers and customers of a company. The model describes the business processes required to satisfy a customer’s demands. It also helps to explain the processes along the entire supply chain and provides a basis for how t...

  12. A Hybrid Support Vector Machines and Two-dimensional Risk Matrix Model for Supply Chain Risk Assessment

    OpenAIRE

    Fan Jiang; Junfei Chen

    2014-01-01

    In recent years, the supply chain managements have been paid more and more attention. The supply chain risk management is an important content for enterprises implementing supply chain management. Therefore, how to measure the risk of supply chain is quite important. In this study, a supply chain risk evaluation model based on support vector machines and two-dimensional risk matrix is proposed. The index system of supply chain risk assessment which includes 14 indices is established. The case...

  13. A Structural Model of Intellectual Capital in Supply Chains

    DEFF Research Database (Denmark)

    Parisi, Cristiana

    performance. This result both contributes to the IC and SCM literature, as it offers a better understanding of the multiple interrelations between the IC components from a SCM perspective and provides evidence of their impact on the value creation process of supply chains.......Intellectual capital (IC) is probably one of the most critical resources of the knowledge society. However, the discipline of IC still needs empirically grounded research, especially with regards to the interrelations between the different component of IC and how these enable or impinge upon...... the internal organisational value creation process. The present paper helps to address the need for empirical investigation about the interconnections between the components of IC and their value creation, by assessing the structural effects of intellectual capital on firms’ financial performance from a supply...

  14. Incorporating demand uncertainty and forecasting in supply chain planning models

    OpenAIRE

    Fildes, R A; Kingsman, B G

    2011-01-01

    This paper develops a framework for examining the effect of demand uncertainty and forecast error on unit costs and customer service levels in the supply chain, including Material Requirements Planning (MRP) type manufacturing systems. The aim is to overcome the methodological limitations and confusion that has arisen in much earlier research. To illustrate the issues, the problem of estimating the value of improving forecasting accuracy for a manufacturer was simulated. The topic is of pract...

  15. Reengineering Model of Supply Chain of Tea Industry in Yunnan

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Yunnan University of finance and Trade recording to t he statistics of chain's output of tea, Yunnan province has entered the ranks of the larger ones of the production in China. Yunnan's tea industry has the natur al resources and the economic effects envied, on the orther hand, Yunnan's tea m arket has gradually become less and the economic effects have been poor. Through our comprehensive investigation and study, we consider that because the supply chain has seriously been disjointed among production...

  16. A Time Efficient Supply Chain Model for an Apparel Company

    OpenAIRE

    Gustafson, Annika; Ng, Sze Lit (Philip); von Schmiesing-Korff, Alice

    2005-01-01

    In most market places today competition has become stronger, not only between single companies but between networks of linked partners, known as supply chains. Consumer demands are changing more often and companies have to react quickly when new trends and consumer requirements appear, thus the competition becomes more time-sensitive. This is especially true in the apparel fashion industry because time is a crucial factor and can make the difference between the success or failure of a company...

  17. An oil demand and supply model incorporating monetary policy

    Energy Technology Data Exchange (ETDEWEB)

    Askari, Hossein [George Washington University, 17795 Canby Road, Leesburg, VA 20175 (United States); Krichene, Noureddine [International Monetary Fund, 700 19th Street, NW, Washington DC 20431 (United States)

    2010-05-15

    Oil price inflation may have had a significant role in pushing the world economy into its worst post-war recession during 2008-2009. Reserve currency central banks pursued an overly expansionary monetary policy during 2001-2009, in the form of low or negative real interest rates and accompanied by a rapidly falling US dollar, while paying inadequate attention to the destabilizing effects on oil markets. In this paper, we show that monetary policy variables, namely key interest rates and the US dollar exchange rate, had a powerful effect on oil markets. World oil demand was significantly influenced by interest and dollar exchange rates, while oil supply was rigid. Oil demand and supply have very low price elasticity and this characteristic makes oil prices highly volatile and subject to wider fluctuations than the prices of other commodities. Aggressive monetary policy would stimulate oil demand, however, it would be met with rigid oil supply and would turn inflationary and disruptive to economic growth if there was little excess capacity in oil output. We argue that a measure of stability in oil markets cannot be achieved unless monetary policy is restrained and real interest rates become significantly positive. Monetary tightening during 1979-1982 might imply that monetary policy has to be restrained for a long period and with high interest rates in order to bring stability back to oil markets. (author)

  18. Control of enterprise interfaces for supply chain enterprise modeling

    Energy Technology Data Exchange (ETDEWEB)

    Interrante, L.D. [Sandia National Labs., Albuquerque, NM (United States); Macfarlane, J.F. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.

    1995-04-01

    There is a current trend for manufacturing enterprises in a supply chain of a particular industry to join forces in an attempt to promote efficiencies and improve competitive position. Such alliances occur in the context of specific legal and business agreements such that each enterprise retains a majority of its business and manufacturing information as private and shares other information with its trading partners. Shared information may include enterprise demand projections, capacities, finished goods inventories, and aggregate production schedules. Evidence of the trend toward information sharing includes the recent emphases on vendor-managed inventories, quick response, and Electronic Data Interchange (EDI) standards. The increased competition brought on by the global marketplace is driving industries to consider the advantages of trading partner agreements. Aggregate-level forecasts, supply-chain production smoothing, and aggregate-level inventory policies can reduce holding costs, record-keeping overhead, and lead time in product development. The goal of this research is to orchestrate information exchange among trading partners to allow for aggregate-level analysis to enhance supply chain efficiency. The notion of Enterprise Interface Control (EIC) is introduced as a means of accomplishing this end.

  19. Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels Conversion Pathway: Fast Pyrolysis and Hydrotreating Bio-Oil Pathway "The 2017 Design Case"

    Energy Technology Data Exchange (ETDEWEB)

    Kevin L. Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J. Bonner; Garold L. Gresham; J. Richard Hess; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

    2014-01-01

    The U.S. Department of Energy promotes the production of liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass sustainable supply, logistics, conversion, and overall system sustainability. As part of its involvement in this program, Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL quantified and the economics and sustainability of moving biomass from the field or stand to the throat of the conversion process using conventional equipment and processes. All previous work to 2012 was designed to improve the efficiency and decrease costs under conventional supply systems. The 2012 programmatic target was to demonstrate a biomass logistics cost of $55/dry Ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model.

  20. Effect of turbulence models on predicting convective heat transfer to hydrocarbon fuel at supercritical pressure

    Institute of Scientific and Technical Information of China (English)

    Tao Zhi; Cheng Zeyuan; Zhu Jianqin; Li Haiwang

    2016-01-01

    A variety of turbulence models were used to perform numerical simulations of heat transfer for hydrocarbon fuel flowing upward and downward through uniformly heated vertical pipes at supercritical pressure. Inlet temperatures varied from 373 K to 663 K, with heat flux rang-ing from 300 kW/m2 to 550 kW/m2. Comparative analyses between predicted and experimental results were used to evaluate the ability of turbulence models to respond to variable thermophys-ical properties of hydrocarbon fuel at supercritical pressure. It was found that the prediction per-formance of turbulence models is mainly determined by the damping function, which enables them to respond differently to local flow conditions. Although prediction accuracy for experimental results varied from condition to condition, the shear stress transport (SST) and launder and sharma models performed better than all other models used in the study. For very small buoyancy-influenced runs, the thermal-induced acceleration due to variations in density lead to the impairment of heat transfer occurring in the vicinity of pseudo-critical points, and heat transfer was enhanced at higher temperatures through the combined action of four thermophysical properties: density, viscosity, thermal conductivity and specific heat. For very large buoyancy-influenced runs, the thermal-induced acceleration effect was over predicted by the LS and AB models.

  1. Effect of turbulence models on predicting convective heat transfer to hydrocarbon fuel at supercritical pressure

    Directory of Open Access Journals (Sweden)

    Tao Zhi

    2016-10-01

    Full Text Available A variety of turbulence models were used to perform numerical simulations of heat transfer for hydrocarbon fuel flowing upward and downward through uniformly heated vertical pipes at supercritical pressure. Inlet temperatures varied from 373 K to 663 K, with heat flux ranging from 300 kW/m2 to 550 kW/m2. Comparative analyses between predicted and experimental results were used to evaluate the ability of turbulence models to respond to variable thermophysical properties of hydrocarbon fuel at supercritical pressure. It was found that the prediction performance of turbulence models is mainly determined by the damping function, which enables them to respond differently to local flow conditions. Although prediction accuracy for experimental results varied from condition to condition, the shear stress transport (SST and launder and sharma models performed better than all other models used in the study. For very small buoyancy-influenced runs, the thermal-induced acceleration due to variations in density lead to the impairment of heat transfer occurring in the vicinity of pseudo-critical points, and heat transfer was enhanced at higher temperatures through the combined action of four thermophysical properties: density, viscosity, thermal conductivity and specific heat. For very large buoyancy-influenced runs, the thermal-induced acceleration effect was over predicted by the LS and AB models.

  2. Developing a Model for Agility in Health Humanitarian Supply Chains Using Factor Analysis: Evidence From Iran

    OpenAIRE

    Jahanbani; Nasiripour; Raeissi; Tabibi

    2014-01-01

    Background Since 2000, increase in frequency and severity of natural disasters has necessitate designing an agile relief supply chain to help to affected people. Objectives This study aimed to develop an agile model for supply chains with emphasis on health services in Iranian relief organizations. Materials and Methods This was a descriptive-comparative study. In order to design t...

  3. Household Labour Supply in Britain and Denmark: Some Interpretations Using a Model of Pareto Optimal Behaviour

    DEFF Research Database (Denmark)

    Barmby, Tim; Smith, Nina

    1996-01-01

    This paper analyses the labour supply behaviour of households in Denmark and Britain. It employs models in which the preferences of individuals within the household are explicitly represented. The households are then assumed to decide on their labour supply in a Pareto-Optimal fashion. Describing...

  4. Risk management in organic coffee supply chains : testing the usefulness of critical risk models

    NARCIS (Netherlands)

    Brusselaers, J.F.; Benninga, J.; Hennen, W.H.G.J.

    2011-01-01

    This report documents the findings of the analysis of the supply chain of organic coffee from Uganda to the Netherlands using a Chain Risk Model (CRM). The CRM considers contamination of organic coffee with chemicals as a threat for the supply chain, and analyses the consequences of contamination in

  5. A Modeling Framework for Supply Chain Simulation: Opportunities for Improved Decision Making

    NARCIS (Netherlands)

    Zee, van der D.J.; Vorst, van der J.G.A.J.

    2005-01-01

    Owing to its inherent modeling flexibility, simulation is often regarded as the proper means for supporting decision making on supply chain design. The ultimate success of supply chain simulation, however, is determined by a combination of the analyst's skills, the chain members' involvement, and th

  6. A modeling framework for supply chain simulation : opportunities for improved decision-making

    NARCIS (Netherlands)

    van der Zee, D.J.; van der Vorst, J.G.A.J.

    2005-01-01

    Owing to its inherent modeling flexibility, simulation is often regarded as the proper means for supporting decision making on supply chain design. The ultimate success of supply chain simulation, however, is determined by a combination of the analyst's skills, the chain members' involvement, and th

  7. Modelling inter-supply chain competition with resource limitation and demand disruption

    Science.gov (United States)

    Chen, Zhaobo; Teng, Chunxian; Zhang, Ding; Sun, Jiayi

    2016-05-01

    This paper proposes a comprehensive model for studying supply chain versus supply chain competition with resource limitation and demand disruption. We assume that there are supply chains with heterogeneous supply network structures that compete at multiple demand markets. Each supply chain is comprised of internal and external firms. The internal firms are coordinated in production and distribution and share some common but limited resources within the supply chain, whereas the external firms are independent and do not share the internal resources. The supply chain managers strive to develop optimal strategies in terms of production level and resource allocation in maximising their profit while facing competition at the end market. The Cournot-Nash equilibrium of this inter-supply chain competition is formulated as a variational inequality problem. We further study the case when there is demand disruption in the plan-execution phase. In such a case, the managers need to revise their planned strategy in order to maximise their profit with the new demand under disruption and minimise the cost of change. We present a bi-criteria decision-making model for supply chain managers and develop the optimal conditions in equilibrium, which again can be formulated by another variational inequality problem. Numerical examples are presented for illustrative purpose.

  8. Modelling healthcare internal service supply chains for the analysis of medication delivery errors and amplification effects

    Directory of Open Access Journals (Sweden)

    Banafsheh Behzad

    2011-12-01

    Full Text Available Purpose: Healthcare is a universally used service that hugely affects economies and the quality of life. The research of service supply chains has found a significant role in the past decade. The main research goal of this paper is to model and simulate the internal service supply chains of a healthcare system to study the effects of different parameters on the outputs and capability measures of the processes. The specific objectives are to analyse medication delivery errors in a community hospital based on the results of the models and to explore the presence of bullwhip effect in the internal service supply chains of the hospital.Design/methodology/approach: System dynamics which is an approach for understanding the behaviour of complex systems, used as a methodology to model two internal service supply chains of the hospital with a sub-model created to simulate medication delivery errors in the hospital. The models are validated using the actual data of the hospital and the results are analyzed based on experimental design techniques.Findings: It is observed that the bullwhip effect may not occur in a hospital’s internal service supply chains. Furthermore the paper points out the conditions for reducing the medication delivery error in a hospital.Research limitations/implications: Because of the community hospital’s data availability the type of service supply chains modelled in this paper, are small service supply chains, representing only the tasks which are done inside the hospital. To better observe the bullwhip effect in healthcare service supply chains, the chains should be modelled more generally.Originality/value: The original system dynamics modelling of the internal service supply chains of a community hospital, with a sub-model simulating the medication delivery error.

  9. Supply Chain Management System Model of Virtual Enterprises Based on Multi-Agent

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; ZHANG Pei-pei

    2008-01-01

    Based on the analysis of a virtual enterprise and the development of supply chain management, their integration is proposed. Then, the difference between multi-agent system modeling method and the traditional modeling method is analyzed, and a method based on Java agent framework for multi-agent systems(JAFMAS) is proposed. By using this method the virtual enterprise's supply chain management system model is established.

  10. Finite Element Modeling of Dynamic Properties of Power Supply for an Industrial Application

    OpenAIRE

    2014-01-01

    In this thesis, the dynamic properties of the mechanic structure of Power Supply for an Industrial Application, an Alstom company product, are considered. A finite element model of the Power Supply mechanic structure have been generated with the aid of the MSC Marc software. Based on the FE model; modal analysis have been carried out and the eigenfrequencies and eigenmodes for the FE model have been calculated in a suitable frequency range. Relevant frequency response functions for the FE mod...

  11. Random Supply, Costant Lead Times and Quadratic Backorder Costs. For Inventory Model (M, T)

    OpenAIRE

    Dr. Martin Omorodion

    2014-01-01

    This paper considers the inventory costs for the (M.T) model in which the backorder costs is quadratic, supply is continuous and lead time is constant. Use is made of series 1: Inventory Model (M.T) with quadratic costs and continuous lead times. The inventory cost for fixed M (maximum re-order level) and constant lead times is averaged over the states of M. Supply is assumed to follow a gamma distribution. The inventory costs for the model, random supply, constants lead time and quadratic co...

  12. The multi-factor recombination and processes superimposition model for hydrocarbon accumulation: application to the Silurian in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Meng Qingyang; Pang Xiongqi; Gao Jianbo

    2008-01-01

    The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors (paleo-anticline,source rock, regional cap rock and kinematic equilibrium belt) controlling hydrocarbon accumulation,this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration of oil and gas in the Silurian of the Tarim basin.

  13. The Implementation of Vendor Managed Inventory In the Supply Chain with Simple Probabilistic Inventory Model

    Directory of Open Access Journals (Sweden)

    Anna Ika Deefi

    2016-01-01

    Full Text Available Numerous studies show that the implementation of Vendor Managed Inventory (VMI benefits all members of the supply chain. This research develops model to prove the benefits obtained from implementing VMI to supplier-buyer partnership analytically. The model considers a two-level supply chain which consists of a single supplier and a single buyer. The analytical model is developed to supply chain inventory with probabilistic demand which follows normal distribution. The model also incorporates lead time as a decision variable and investigates the impacts of inventory management before and after the implementation of the VMI. The result shows that the analytical model has the ability to reduce the supply chain expected cost, improve the service level and increase the inventory replenishment. Numerical examples are given to prove them.

  14. Modelling fate and effects of toxicologically relevant hydrocarbon fractions following hypothetical oil spills in a marine environment

    Energy Technology Data Exchange (ETDEWEB)

    St-Amand, A.; Mazzocco, P.; Stephenson, M. [Stantec Consulting Ltd., Fredericton, NB (Canada)

    2009-07-01

    Numerical oil spill models have generally focused on the transport and fate of oil following a spill through processes such as advection, evaporation, spreading dissolution, dispersion, emulsification, biodegradation and sedimentation. These models provide information regarding the trajectory, location and size of the oil slick, as well as the location where the slick will touch shorelines. The models normally treat the spilled hydrocarbon as a single product or group of representative compounds which is not very useful in evaluating toxicological risks to aquatic biota. For that reason, Stantec developed a model that simultaneously evaluates the likely fate and co-toxicity of toxicologically relevant hydrocarbon compounds and fractions in water following an oil spill in a marine environment. Compounds currently considered in the model include polycyclic aromatic hydrocarbons, volatile organic compounds, BTEX compounds, (benzene, toluene, ethylbenzene, xylenes) and the Canada-Wide Standard hydrocarbon fractions. The fate of these hydrocarbons in the marine environment was simulated using a mass-balance compartment approach in which specific states of the oil and relevant environmental media were considered. At each time step following the hydrocarbon release, the model updated physical properties such as the density and viscosity of the spilled mixtures. When predicting the fate of the mixture, environmental conditions such as wind speed and wave height were taken into account to determine whether droplets of the spilled product remained entrained in the water column or if they resurfaced and possibly emulsified. Two hypothetical spill scenarios were investigated based on assumed spill volumes, assumed product compositions representing a distilled product and crude oil, and assumed environmental and meteorological conditions. The key outputs of the model were the dissolved concentrations of toxicologically relevant hydrocarbon compounds and fractions in the water

  15. Critical evaluation of paradigms for modelling integrated supply chains

    NARCIS (Netherlands)

    Van Dam, K.H.; Adhitya, A.; Srinivasan, R.; Lukszo, Z.

    2009-01-01

    Contemporary problems in process systems engineering often require model-based decision support tool. Among the various modelling paradigms, equation-based models and agent-based models are widely used to develop dynamic models of systems. Which is the most appropriate modelling paradigm for a suppl

  16. A General Simulation Framework for Supply Chain Modeling: State of the Art and Case Study

    Directory of Open Access Journals (Sweden)

    Antonio Cimino

    2010-03-01

    Full Text Available Nowadays there is a large availability of discrete event simulation software that can be easily used in different domains: from industry to supply chain, from healthcare to business management, from training to complex systems design. Simulation engines of commercial discrete event simulation software use specific rules and logics for simulation time and events management. Difficulties and limitations come up when commercial discrete event simulation software are used for modeling complex real world-systems (i.e. supply chains, industrial plants. The objective of this paper is twofold: first a state of the art on commercial discrete event simulation software and an overview on discrete event simulation models development by using general purpose programming languages are presented; then a Supply Chain Order Performance Simulator (SCOPS, developed in C++ for investigating the inventory management problem along the supply chain under different supply chain scenarios is proposed to readers.

  17. A robust optimization model for agile and build-to-order supply chain planning under uncertainties

    DEFF Research Database (Denmark)

    Lalmazloumian, Morteza; Wong, Kuan Yew; Govindan, Kannan

    2015-01-01

    Supply chain planning as one of the most important processes within the supply chain management concept, has a great impact on firms' success or failure. This paper considers a supply chain planning problem of an agile manufacturing company operating in a build-to-order environment under various...... kinds of uncertainty. An integrated optimization approach of procurement, production and distribution costs associated with the supply chain members has been taken into account. A robust optimization scenario-based approach is used to absorb the influence of uncertain parameters and variables....... The formulation is a robust optimization model with the objective of minimizing the expected total supply chain cost while maintaining customer service level. The developed multi-product, multi-period, multi-echelon robust mixed-integer linear programming model is then solved using the CPLEX optimization studio...

  18. A General Simulation Framework for Supply Chain Modeling: State of the Art and Case Study

    CERN Document Server

    Cimino, Antonio; Mirabelli, Giovanni

    2010-01-01

    Nowadays there is a large availability of discrete event simulation software that can be easily used in different domains: from industry to supply chain, from healthcare to business management, from training to complex systems design. Simulation engines of commercial discrete event simulation software use specific rules and logics for simulation time and events management. Difficulties and limitations come up when commercial discrete event simulation software are used for modeling complex real world-systems (i.e. supply chains, industrial plants). The objective of this paper is twofold: first a state of the art on commercial discrete event simulation software and an overview on discrete event simulation models development by using general purpose programming languages are presented; then a Supply Chain Order Performance Simulator (SCOPS, developed in C++) for investigating the inventory management problem along the supply chain under different supply chain scenarios is proposed to readers.

  19. Dynamics of global supply chain and electric power networks: Models, pricing analysis, and computations

    Science.gov (United States)

    Matsypura, Dmytro

    In this dissertation, I develop a new theoretical framework for the modeling, pricing analysis, and computation of solutions to electric power supply chains with power generators, suppliers, transmission service providers, and the inclusion of consumer demands. In particular, I advocate the application of finite-dimensional variational inequality theory, projected dynamical systems theory, game theory, network theory, and other tools that have been recently proposed for the modeling and analysis of supply chain networks (cf. Nagurney (2006)) to electric power markets. This dissertation contributes to the extant literature on the modeling, analysis, and solution of supply chain networks, including global supply chains, in general, and electric power supply chains, in particular, in the following ways. It develops a theoretical framework for modeling, pricing analysis, and computation of electric power flows/transactions in electric power systems using the rationale for supply chain analysis. The models developed include both static and dynamic ones. The dissertation also adds a new dimension to the methodology of the theory of projected dynamical systems by proving that, irrespective of the speeds of adjustment, the equilibrium of the system remains the same. Finally, I include alternative fuel suppliers, along with their behavior into the supply chain modeling and analysis framework. This dissertation has strong practical implications. In an era in which technology and globalization, coupled with increasing risk and uncertainty, complicate electricity demand and supply within and between nations, the successful management of electric power systems and pricing become increasingly pressing topics with relevance not only for economic prosperity but also national security. This dissertation addresses such related topics by providing models, pricing tools, and algorithms for decentralized electric power supply chains. This dissertation is based heavily on the following

  20. A Hybrid Support Vector Machines and Two-dimensional Risk Matrix Model for Supply Chain Risk Assessment

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    2014-03-01

    Full Text Available In recent years, the supply chain managements have been paid more and more attention. The supply chain risk management is an important content for enterprises implementing supply chain management. Therefore, how to measure the risk of supply chain is quite important. In this study, a supply chain risk evaluation model based on support vector machines and two-dimensional risk matrix is proposed. The index system of supply chain risk assessment which includes 14 indices is established. The case study shows that the proposed model is reasonable, effective and it can provide an important reference for supply chain risk management.

  1. Approaches for externally validated QSAR modelling of Nitrated Polycyclic Aromatic Hydrocarbon mutagenicity.

    Science.gov (United States)

    Gramatica, P; Pilutti, P; Papa, E

    2007-01-01

    Nitrated Polycyclic Aromatic Hydrocarbons (nitro-PAHs), ubiquitous environmental pollutants, are recognized mutagens and carcinogens. A set of mutagenicity data (TA100) for 48 nitro-PAHs was modeled by the Quantitative Structure-Activity Relationships (QSAR) regression method, and OECD principles for QSAR model validation were applied. The proposed Multiple Linear Regression (MLR) models are based on two topological molecular descriptors. The models were validated for predictivity by both internal and external validation. For the external validation, three different splitting approaches, D-optimal Experimental Design, Self Organizing Maps (SOM) and Random Selection by activity sampling, were applied to the original data set in order to compare these methodologies and to select the best descriptors able to model each prediction set chemicals independently of the splitting method applied. The applicability domain was verified by the leverage approach.

  2. BIOB: a mathematical model for the biodegradation of low solubility hydrocarbons.

    Science.gov (United States)

    Geng, Xiaolong; Boufadel, Michel C; Personna, Yves R; Lee, Ken; Tsao, David; Demicco, Erik D

    2014-06-15

    Modeling oil biodegradation is an important step in predicting the long term fate of oil on beaches. Unfortunately, existing models do not account mechanistically for environmental factors, such as pore water nutrient concentration, affecting oil biodegradation, rather in an empirical way. We present herein a numerical model, BIOB, to simulate the biodegradation of insoluble attached hydrocarbon. The model was used to simulate an experimental oil spill on a sand beach. The biodegradation kinetic parameters were estimated by fitting the model to the experimental data of alkanes and aromatics. It was found that parameter values are comparable to their counterparts for the biodegradation of dissolved organic matter. The biodegradation of aromatics was highly affected by the decay of aromatic biomass, probably due to its low growth rate. Numerical simulations revealed that the biodegradation rate increases by 3-4 folds when the nutrient concentration is increased from 0.2 to 2.0 mg N/L.

  3. SCRL-Model for Human Space Flight Operations Enterprise Supply Chain

    Science.gov (United States)

    Tucker, Brian; Paxton, Joseph

    2010-01-01

    This paper will present a Supply Chain Readiness Level (SCRL) model that can be used to evaluate and configure adaptable and sustainable program and mission supply chains at an enterprise level. It will also show that using SCRL in conjunction with Technology Readiness Levels (TRLs), Manufacturing Readiness Levels (MRLs) and National Aeronautics Space Administrations (NASA s) Project Lifecycle Process will provide a more complete means of developing and evaluating a robust sustainable supply chain that encompasses the entire product, system and mission lifecycle. In addition, it will be shown that by implementing the SCRL model, NASA can additionally define supplier requirements to enable effective supply chain management (SCM). Developing and evaluating overall supply chain readiness for any product, system and mission lifecycle is critical for mission success. Readiness levels are presently being used to evaluate the maturity of technology and manufacturing capability during development and deployment phases of products and systems. For example, TRLs are used to support the assessment of the maturity of a particular technology and compare maturity of different types of technologies. MRLs are designed to assess the maturity and risk of a given technology from a manufacturing perspective. In addition, when these measurement systems are used collectively they can offer a more comprehensive view of the maturity of the system. While some aspects of the supply chain and supply chain planning are considered in these familiar metric systems, certain characteristics of an effective supply chain, when evaluated in more detail, will provide an improved insight into the readiness and risk throughout the supply chain. Therefore, a system that concentrates particularly on supply chain attributes is required to better assess enterprise supply chain readiness.

  4. SCRL-Model for Human Space Flight Operations Enterprise Supply Chain

    Science.gov (United States)

    Tucker, Brian; Paxton, Joseph

    2010-01-01

    This paper will present a Supply Chain Readiness Level (SCRL) model that can be used to evaluate and configure adaptable and sustainable program and mission supply chains at an enterprise level. It will also show that using SCRL in conjunction with Technology Readiness Levels (TRLs), Manufacturing Readiness Levels (MRLs) and National Aeronautics Space Administrations (NASA s) Project Lifecycle Process will provide a more complete means of developing and evaluating a robust sustainable supply chain that encompasses the entire product, system and mission lifecycle. In addition, it will be shown that by implementing the SCRL model, NASA can additionally define supplier requirements to enable effective supply chain management (SCM). Developing and evaluating overall supply chain readiness for any product, system and mission lifecycle is critical for mission success. Readiness levels are presently being used to evaluate the maturity of technology and manufacturing capability during development and deployment phases of products and systems. For example, TRLs are used to support the assessment of the maturity of a particular technology and compare maturity of different types of technologies. MRLs are designed to assess the maturity and risk of a given technology from a manufacturing perspective. In addition, when these measurement systems are used collectively they can offer a more comprehensive view of the maturity of the system. While some aspects of the supply chain and supply chain planning are considered in these familiar metric systems, certain characteristics of an effective supply chain, when evaluated in more detail, will provide an improved insight into the readiness and risk throughout the supply chain. Therefore, a system that concentrates particularly on supply chain attributes is required to better assess enterprise supply chain readiness.

  5. A MULTI-OBJECTIVE ROBUST OPERATION MODEL FORELECTRONIC MARKET ENABLED SUPPLY CHAIN WITH UNCERTAIN DEMANDS

    Institute of Scientific and Technical Information of China (English)

    Jiawang XU; Xiaoyuan HUANG; Nina YAN

    2007-01-01

    A multi-objective robust operation model is proposed in this paper for an electronic market enabled supply chain consisting of multi-supplier and multi-customer with uncertain demands.Suppliers in this supply chain provide many kinds of products to different customers directly or through electronic market.Uncertain demands are described as a scenario set with certain probability; the supply chain operation model is constructed by using the robust optimization method based on scenario analyses.The operation model we proposed is a multi-objective programming problem satisfying several conflict objectives,such as meeting the demands of all customers,minimizing the system cost,the availabilities of suppliers' capacities not below a certain level,and robustness of decision to uncertain demands.The results of numerical examples proved that the solution of the model is most conservative; however,it can ensure the robustness of the operation of the supply chain effectively.

  6. The sustainability of urban water supply in low income countries: a livelihoods model

    NARCIS (Netherlands)

    Hadipuro, W.; Wiering, M.A.; Naerssen, A.L. van

    2013-01-01

    Urban water supply can be managed by public institutions, private companies, communities, or by combinations thereof. Controversy continues over which system can most effectively improve livelihoods. Responding to this discussion, an extended model of sustainable livelihoods analysis is proposed tha

  7. Modelling the Effects of Parking Charge and Supply Policy Using System Dynamics Method

    National Research Council Canada - National Science Library

    Zhenyu Mei; Qifeng Lou; Wei Zhang; Lihui Zhang; Fei Shi

    2017-01-01

    .... This paper develops an evaluation model for parking policies using system dynamics. A quantitative study is conducted to examine the effects of parking charge and supply policy on traffic speed...

  8. Capacity modelling of the coal value chain at Sasol Coal Supply

    CSIR Research Space (South Africa)

    Harmse, M

    2007-05-01

    Full Text Available plants. The plants must be supplied with adequate coal to sustain production. A simulation model was built to test the feasibility of blending the coal from the mines according to a weekly blend plan....

  9. Optimal design of supply chain network under uncertainty environment using hybrid analytical and simulation modeling approach

    Science.gov (United States)

    Chiadamrong, N.; Piyathanavong, V.

    2017-04-01

    Models that aim to optimize the design of supply chain networks have gained more interest in the supply chain literature. Mixed-integer linear programming and discrete-event simulation are widely used for such an optimization problem. We present a hybrid approach to support decisions for supply chain network design using a combination of analytical and discrete-event simulation models. The proposed approach is based on iterative procedures until the difference between subsequent solutions satisfies the pre-determined termination criteria. The effectiveness of proposed approach is illustrated by an example, which shows closer to optimal results with much faster solving time than the results obtained from the conventional simulation-based optimization model. The efficacy of this proposed hybrid approach is promising and can be applied as a powerful tool in designing a real supply chain network. It also provides the possibility to model and solve more realistic problems, which incorporate dynamism and uncertainty.

  10. The sustainability of urban water supply in low income countries: a livelihoods model

    NARCIS (Netherlands)

    Hadipuro, W.; Wiering, M.A.; Naerssen, A.L. van

    2013-01-01

    Urban water supply can be managed by public institutions, private companies, communities, or by combinations thereof. Controversy continues over which system can most effectively improve livelihoods. Responding to this discussion, an extended model of sustainable livelihoods analysis is proposed tha

  11. Modelling of Switched Mode Fly-back Supply for Engineering Education

    Directory of Open Access Journals (Sweden)

    TRIP, N. D.

    2010-02-01

    Full Text Available This paper presents a modelling method useful in the education process for the study of DC-DC power conversion principles using pulse width modulation converters. In this paper, the proposed modelling method is applied to a switched mode Fly-back supply. The model of the supply circuit includes the main parasitic elements of its component parts. To analyze the operation mode of the switched mode Fly-back supply its model is implemented with the help of MATLAB programming environment. The implementation of the model is used to simulate the behaviour of the Fly-back supply for both continuous conduction and discontinuous conduction modes, in transient and steady state conditions. The model and its implementation offer to the users an easier way to understand and analyze the operation principle of the switched mode power supplies. Moreover, the authors developed a graphic user interface dedicated to this study. The paper includes simulation and experimental results that validate the model of the supply.

  12. A cost optimization model for 100% renewable residential energy supply systems

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2012-01-01

    for the interdependencies between the different supply technologies as well as the construction energy of the installations, consumption profiles and on-site energy resource availability. This paper aims at developing such a model for the optimal sizing of renewable energy supply systems (RES) for residential Net ZEB......'s involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system costs. It has been successfully applied...

  13. A Framework of Multi Objectives Negotiation for Dynamic Supply Chain Model

    Science.gov (United States)

    Chai, Jia Yee; Sakaguchi, Tatsuhiko; Shirase, Keiichi

    Trends of globalization and advances in Information Technology (IT) have created opportunity in collaborative manufacturing across national borders. A dynamic supply chain utilizes these advances to enable more flexibility in business cooperation. This research proposes a concurrent decision making framework for a three echelons dynamic supply chain model. The dynamic supply chain is formed by autonomous negotiation among agents based on multi agents approach. Instead of generating negotiation aspects (such as amount, price and due date) arbitrary, this framework proposes to utilize the information available at operational level of an organization in order to generate realistic negotiation aspect. The effectiveness of the proposed model is demonstrated by various case studies.

  14. A simple one-step chemistry model for partially premixed hydrocarbon combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Tarrazo, Eduardo [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Sanchez, Antonio L. [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Linan, Amable [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2006-10-15

    This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T{sub a}, and the preexponential factor B. It is seen that changes in q with equivalence ratio f need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(f) for f>1 for all hydrocarbons. The model also employs a variable activation temperature T{sub a}(f) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (author)

  15. Assessment of atmospheric distribution of polychlorinated biphenyls and polycyclic aromatic hydrocarbons using polyparameter model

    Directory of Open Access Journals (Sweden)

    Turk-Sekulić Maja M.

    2011-01-01

    Full Text Available Results of partial or total destruction of industrial plants, military targets, infrastructure, uncontrolled fires and explosions during the conflict period from 1991 to 1999, at the area of Western Balkans, were large amounts of hazardous organic matter that have been generated and emitted in the environment. In order to assess gas/particle partition of seven EPA polychlorinated biphenyls and sixteen EPA polycyclic aromatic hydrocarbons, twenty air samples have been collected at six urban, industrial and highly contaminated localities in Vojvodina. Hi-Vol methodology has been used for collecting ambiental air samples, that simultaneously collects gaseous and particulate phase with polyurethane foam filters (PUF and glass fiber filters (GFF. PUF and GFF filters have been analyzed, and concentration levels of gaseous PCBs and PAHs molecules in gaseous and particulate phase were obtained, converted and expressed through fraction of individual compounds sorbed onto particulate phase of the sample, in total detected quantity. Experimentally gained gas/particle partitioning values of PCBs and PAHs molecules have been compared with PP-LFER model estimated values. Significant deviation has been noticed during comparative analysis of estimated polyparameter model values for complete set of seven PCBs congeners. Much better agreement of experimental and estimated values is for polycyclic aromatic hydrocarbons, especially for molecules with four rings. These results are in a good correlation with literature data where polyparameter model has been used for predicting gas/particle partition of studied group of organic molecules.

  16. Development of oil supply and demand planning model for mid- and long-term

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hyun [Korea Energy Economics Institute, Euiwang (Korea)

    1997-10-01

    Despite the liberalization of oil market, a systematic model is required for reasonable supply and demand of oil, which still has an important influence on industry and state economy. It is required a demand model deriving prospects of each sector and product and a supply model examining the optimum rate of operation, production mix of products, stock, export and import, and the size of equipment investment to meet given demand. As the first phase for the development of supply and demand model, the existing oil and energy models in domestic and overseas were reviewed and recommendations for establishing a Korean oil supply and demand model were derived in this study. Based on these, a principle for establishing a model and a rough framework were set up. In advance of mid- and long-term prospects, a short-term prospect model was established and the short-term prospects for the first quarter of 1999 and for the year 1999 were presented on trial. Due to the size and characters of a supply model, a plan for an ideal model was first explained and then a plan for creating a model step by step was presented as a realistic scheme. (author). 16 refs., 9 figs., 19 tabs.

  17. A strategic capacity allocation model for a complex supply chain: formulation and solution approach comparison

    OpenAIRE

    Li, H.; Hendry, L; Teunter, R.H.

    2009-01-01

    In this paper, a capacity allocation problem is discussed based on a more complex supply chain than has been typically considered in previous quantitative modelling studies. This study analyses an integrated supply chain operation from raw material purchasing to final product distribution. The aim is to optimize the allocation of capacities among different facilities and product items. In this paper, a mixed integer programming model with dynamic characteristics is presented first, and then a...

  18. NEMS International Energy Module, model documentation report: World Oil Market, Petroleum Products Supply and Oxygenates Supply components

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-04

    The Energy Information Administration (EIA) is developing the National Energy Modeling System (NEMS) to enhance its energy forecasting capabilities and to provide the Department of Energy with a comprehensive framework for analyzing alternative energy` futures. NEMS is designed with a multi-level modular structure that represents specific energy supply activities, conversion processes, and demand sectors as a series of self-contained units which are linked by an integrating mechanism. The NEMS International Energy Module (IEM) computes world oil prices and the resulting patterns of international trade in crude oil and refined products. This report is a reference document for energy analysts, model users, and the public that is intended to meet EIA`s legal obligation to provide adequate documentation for all statistical and forecast reports (Public Law 93-275, section 57(b)(1). Its purpose is to describe the structure of the IEM. Actual operation of the model is not discussed here. The report contains four sections summarizing the overall structure of the IEM and its interface with other NEMS modules, mathematical specifications of behavioral relationships, and data sources and estimation methods. Following a general description of the function and rationale of its key components, system and equation level information sufficient to permit independent evaluation of the model`s technical details is presented.

  19. Comparing Supply-Side Specifications in Models of Global Agriculture and the Food System

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Sherman; van Meijl, Hans; Willenbockel, Dirk; Valin, Hugo; Fujimori, Shinichiro; Masui, Toshihiko; Sands, Ronald; Wise, Marshall A.; Calvin, Katherine V.; Havlik, Petr; Mason d' Croz, Daniel; Tabeau, Andrzej; Kavallari, Aikaterini; Schmitz, Christoph; Dietrich, Jan P.; von Lampe, Martin

    2014-01-01

    This paper compares the theoretical specification of production and technical change across the partial equilibrium (PE) and computable general equilibrium (CGE) models of the global agricultural and food system included in the AgMIP model comparison study. The two modeling approaches have different theoretical underpinnings concerning the scope of economic activity they capture and how they represent technology and the behavior of supply and demand in markets. This paper focuses on their different specifications of technology and supply behavior, comparing their theoretical and empirical treatments. While the models differ widely in their specifications of technology, both within and between the PE and CGE classes of models, we find that the theoretical responsiveness of supply to changes in prices can be similar, depending on parameter choices that define the behavior of supply functions over the domain of applicability defined by the common scenarios used in the AgMIP comparisons. In particular, we compare the theoretical specification of supply in CGE models with neoclassical production functions and PE models that focus on land and crop yields in agriculture. In practice, however, comparability of results given parameter choices is an empirical question, and the models differ in their sensitivity to variations in specification. To illustrate the issues, sensitivity analysis is done with one global CGE model, MAGNET, to indicate how the results vary with different specification of technical change, and how they compare with the results from PE models.

  20. Establishment of Grain Farmers’ Supply Response Model and Empirical Analysis under Minimum Grain Purchase Price Policy

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Based on farmers’ supply behavior theory and price expectations theory,this paper establishes grain farmers’ supply response model of two major grain varieties (early indica rice and mixed wheat) in the major producing areas,to test whether the minimum grain purchase price policy can have price-oriented effect on grain production and supply in the major producing areas. Empirical analysis shows that the minimum purchase price published annually by the government has significant positive impact on farmers’ grain supply in the major grain producing areas. In recent years,China steadily raises the level of minimum grain purchase price,which has played an important role in effectively protecting grain farmers’ interests,mobilizing the enthusiasm of farmers’ grain production,and ensuring the market supply of key grain varieties.

  1. Development of S-ARIMA Model for Forecasting Demand in a Beverage Supply Chain

    Science.gov (United States)

    Mircetic, Dejan; Nikolicic, Svetlana; Maslaric, Marinko; Ralevic, Nebojsa; Debelic, Borna

    2016-11-01

    Demand forecasting is one of the key activities in planning the freight flows in supply chains, and accordingly it is essential for planning and scheduling of logistic activities within observed supply chain. Accurate demand forecasting models directly influence the decrease of logistics costs, since they provide an assessment of customer demand. Customer demand is a key component for planning all logistic processes in supply chain, and therefore determining levels of customer demand is of great interest for supply chain managers. In this paper we deal with exactly this kind of problem, and we develop the seasonal Autoregressive IntegratedMoving Average (SARIMA) model for forecasting demand patterns of a major product of an observed beverage company. The model is easy to understand, flexible to use and appropriate for assisting the expert in decision making process about consumer demand in particular periods.

  2. The Export Supply Model of Bangladesh: An Application of Cointegration and Vector Error Correction Approaches

    Directory of Open Access Journals (Sweden)

    Mahmudul Mannan Toy

    2011-01-01

    Full Text Available The broad objective of this study is to empirically estimate the export supply model of Bangladesh. The techniques of cointegration, Engle-Granger causality and Vector Error Correction are applied to estimate the export supply model. The econometric analysis is done by using the time series data of the variables of interest which is collected from various secondary sources. The study has empirically tested the hypothesis, long run relationship and casualty between variables of the model. The cointegration analysis shows that all the variables of the study are co-integrated at their first differences meaning that there exists long run relationship among the variables. The VECM estimation shows the dynamics of variables in the export supply function and the short run and long run elasticities of export supply with respect to each independent variable. The error correction term is found negative which indicates that any short run disequilibrium will be turned into equilibrium in the long run.

  3. Energy reserves. [Summary of reserve estimates and economic supply models for exhaustible resources

    Energy Technology Data Exchange (ETDEWEB)

    Tessmer, R.G. Jr.; Carhart, S.C.; Marcuse, W.

    1977-03-01

    There is an increasing concern about scarcity of the world's remaining natural energy resources and, in particular, the future supply of oil and natural gas. This paper summarizes recent estimates of energy reserves and economic supply models for exhaustible resources. The basic economic theory of resource exhaustion is reviewed, and recent estimates of both discovered and undiscovered energy resources are presented and compared. Domestic and world-wide reserve estimates are presented for crude oil and natural gas liquids, natural gas, coal, and uranium. Economic models projecting supply of these energy forms, given reserve estimates and other pertinent information, are discussed. Finally, a set of recent models which project world oil prices are summarized and their published results compared. The impact of energy conservation efforts on energy supply is also briefly discussed. 53 references.

  4. Opportunities and challenges in supply-side simulation: physician-based models.

    Science.gov (United States)

    Gresenz, Carole Roan; Auerbach, David I; Duarte, Fabian

    2013-04-01

    To provide a conceptual framework and to assess the availability of empirical data for supply-side microsimulation modeling in the context of health care. Multiple secondary data sources, including the American Community Survey, Health Tracking Physician Survey, and SK&A physician database. We apply our conceptual framework to one entity in the health care market-physicians-and identify, assess, and compare data available for physician-based simulation models. Our conceptual framework describes three broad types of data required for supply-side microsimulation modeling. Our assessment of available data for modeling physician behavior suggests broad comparability across various sources on several dimensions and highlights the need for significant integration of data across multiple sources to provide a platform adequate for modeling. A growing literature provides potential estimates for use as behavioral parameters that could serve as the models' engines. Sources of data for simulation modeling that account for the complex organizational and financial relationships among physicians and other supply-side entities are limited. A key challenge for supply-side microsimulation modeling is optimally combining available data to harness their collective power. Several possibilities also exist for novel data collection. These have the potential to serve as catalysts for the next generation of supply-side-focused simulation models to inform health policy. © Health Research and Educational Trust.

  5. Opportunities and Challenges in Supply-Side Simulation: Physician-Based Models

    Science.gov (United States)

    Gresenz, Carole Roan; Auerbach, David I; Duarte, Fabian

    2013-01-01

    Objective To provide a conceptual framework and to assess the availability of empirical data for supply-side microsimulation modeling in the context of health care. Data Sources Multiple secondary data sources, including the American Community Survey, Health Tracking Physician Survey, and SK&A physician database. Study Design We apply our conceptual framework to one entity in the health care market—physicians—and identify, assess, and compare data available for physician-based simulation models. Principal Findings Our conceptual framework describes three broad types of data required for supply-side microsimulation modeling. Our assessment of available data for modeling physician behavior suggests broad comparability across various sources on several dimensions and highlights the need for significant integration of data across multiple sources to provide a platform adequate for modeling. A growing literature provides potential estimates for use as behavioral parameters that could serve as the models' engines. Sources of data for simulation modeling that account for the complex organizational and financial relationships among physicians and other supply-side entities are limited. Conclusions A key challenge for supply-side microsimulation modeling is optimally combining available data to harness their collective power. Several possibilities also exist for novel data collection. These have the potential to serve as catalysts for the next generation of supply-side-focused simulation models to inform health policy. PMID:23347041

  6. Revenue-Sharing Contract Models for Logistics Service Supply Chains with Mass Customization Service

    Directory of Open Access Journals (Sweden)

    Weihua Liu

    2015-01-01

    Full Text Available The revenue-sharing contract is one of the most important supply chain coordination contracts; it has been applied in various supply chains. However, studies related to service supply chains with mass customization (MC are lacking. Considering the equity of benefit distribution between the members of service supply chains, in this paper, we designed two revenue-sharing contracts. The first contract for the maximum equity of a single logistics service integrator (LSI and single functional logistics service provider (FLSP in a two-echelon logistics service supply chain was designed by introducing the fair entropy function (“one to one” model. Furthermore, the method is extended to a more complex supply chain, which consists of a single LSI and multiple FLSPs. A new contract was designed not only for considering the equity of an LSI and each FLSP but also for the equity between each FLSP (“one to N” model. The “one to one” model in three-echelon LSSC is also provided. The result exemplifies that, whether in the “one to one” model or “one to N” model, there exists a best interval of customized level when the revenue-sharing coefficient reaches its maximum.

  7. Overview of the Spanish electricity supply industry model

    Energy Technology Data Exchange (ETDEWEB)

    Galvez, J.B.; Collado, R.J. (ENDESA (Spain))

    1993-01-01

    The Spanish Electricity Supply Industry (ESI) is a fairly large, well diversified industry which has undergone substantial changes during the last decade, aimed at achieving three distinct objectives: maximum economic efficiency; maintenance of the ESI as a national energy policy tool; and flexibility vis-a-vis a changing environment. The changes have affected the three structural elements of the system: industrial and business structure, tending towards a greater horizontalization of the industry and consolidation of the companies involved; system management and operation, under the perspective of an integrated system with regard to key decisions both in the long-term (i.e. capacity planning) and short-term (i.e. energy dispatching system); and tariff and price regulation in the context of a country-wide single tariff, aimed at promoting system efficiency and 'yardstick' competition through the use of 'standard costs' for all cost items in all parts of the system. Beyond these initial changes, there are new elements under consideration and developed in a new Law for the Structuring of the Electric System, blocked at present by the impending elections. This new Law would maintain the perspective of the integrated system while allowing for competition in certain areas (i.e. new generation, 'energy sellers') and promoting greater transparency with the segregation of activities (Generation, Transmission, Distribution, and 'Energy Sales').

  8. Modelling of Sudan’s Energy Supply, Transformation, and Demand

    Directory of Open Access Journals (Sweden)

    Ali A. Rabah

    2016-01-01

    Full Text Available The study aimed to develop energy flow diagram (Sankey diagram of Sudan for the base year 2014. The developed Sankey diagram is the first of its kind in Sudan. The available energy balance for the base year 2012 is a simple line draw and did not count the energy supply by private and mixed sectors such as sugar and oil industries and marine and civil aviation. The private and mixed sectors account for about 7% of the national grid electric power. Four energy modules are developed: resources, transformation, demand, and export and import modules. The data are obtained from relevant Sudanese ministries and directorates and Sudan Central Bank. “e!Sankey 4 pro” software is used to develop the Sankey diagram. The main primary types of energy in Sudan are oil, hydro, biomass, and renewable energy. Sudan has a surplus of gasoline, petroleum coke, and biomass and deficit in electric power, gasoil, jet oil, and LPG. The surplus of gasoline is exported; however, the petroleum coke is kept as reserve. The deficit is covered by import. The overall useful energy is 76% and the loss is 24%. The useful energy is distributed among residential (38%, transportation (33%, industry (12%, services (16%, and agriculture (1% sectors.

  9. Fuzzy Multi-Objective Programming Model for Facility Location in an Integrated Supply Chain Network

    Directory of Open Access Journals (Sweden)

    Hüseyin Ali Sarıkaya

    2014-05-01

    Full Text Available Traditional supply chain network design problems are often taken as a single objective. However, supply chains are complex networks formed by organizations having conflicting objectives with each other in real life. In this study, a multi-product, multi-stage and multi-period planning model is proposed to achieve multiple incommensurable goals in an integrated supply chain network with uncertain market demands. The supply chain planning model is constructed as a mixed-integer nonlinear programming problem to satisfy several conflicting objectives with each other. The proposed model consists of two objective functions. The first one is minimizing the fixed opening and operating costs with transportation costs determined depending on distances. Second one is minimizing the purchasing, ordering, inventory and backlogging costs according to Economic Production Quantity (EPQ model. Fuzzy goal programming approach is used in order to include decision maker's imprecise goal values in proposed model. The model is solved using GAMS optimization program. The application results presented in this study, demonstrates that fuzzy modeling and solution approaches could be used in the creation of more realistic models of the supply chain.

  10. Dynamic Model of Urban Sports Infrastructure Supply and Demand Based on GDP Growth

    Directory of Open Access Journals (Sweden)

    Wenjing Zhang

    2014-01-01

    Full Text Available For different city, the change rate of the supply and demand of the sports infrastructure is not the same and is subject to regional GDP growth constraints. Taking GDP growth as control variables, a dynamic model of multi-city sports infrastructure supply and demand system was established. According to Lyapunov stability theory, the system asymptotically stable condition was obtained. Using the linear matrix inequality method, the paper gets a control method that cities with different development level can be unified use for making their sports infrastructure system asymptotically stable and supply-demand equilibrium. The method can reduce the cities’ sports infrastructure construction control complexity.

  11. A new complete model of switch-mode plasma cutting power supply

    Institute of Scientific and Technical Information of China (English)

    Abdolreza Esmaeli; SUN Li(孙力); NIE Jian-hong(聂剑红)

    2004-01-01

    A complete model of switch-mode plasma cutting power supply and its simulation are developed. The full bridge isolated pulse width modulation (PWM) buck converter in continuous conduction mode (CCM) for high watt plasma power supply is approached. Reduced ripple current and improved power factor are achieved in the plasma power supply. With a PID control strategy, circuit responses become more stable and faster with low overshoot during load and current changing. The converter achieved high efficiency under 3 to 15kW load conditions.

  12. The spread model of food safety risk under the supply-demand disturbance

    OpenAIRE

    Wang, Jining; Chen, Tingqiang

    2016-01-01

    In this paper, based on the imbalance of the supply-demand relationship of food, we design a spreading model of food safety risk, which is about from food producers to consumers in the food supply chain. We use theoretical analysis and numerical simulation to describe the supply-demand relationship and government supervision behaviors’ influence on the risk spread of food safety and the behaviors of the food producers and the food retailers. We also analyze the influence of the awareness of c...

  13. A new Integration Model to Evaluate Strategic Performance of Supply Chain

    Directory of Open Access Journals (Sweden)

    Gholamreza Gholampour

    2014-12-01

    Full Text Available Nowadays, Supply Chain Management (SCM is one of the most important and complex issues for automakers in the world. The main objectives of this research were to investigate the factors that predict strategic performance of supply chain by doing quantitative research at Iran Khodro Company (IKCO in Iran. Based on supply chain theories, strategic performance of supply chain was predicted by Information Technology (IT, Organizational Learning (OL, and Product Innovation (PRI in our research at the first time in an automotive company. Stratified random sampling was used to determine the sample size. Accordingly, 250 questionnaires were distributed among experts and supply chain specialists at IKCO. According to Supplying Automotive Parts Company (SPSC variable as the main dependent variable, Path Analysis (PA technique was used to explore casual relationships among variables using multiple regression analysis in SPSS. The Confirmatory Factor Analysis (CFA was utilized based on Maximum Likelihood (ML analysis of normality, outliers, composite reliability, and validity to test hypotheses by using AMOS. PA, measurement model, and structural model were analyzed in order to examine the conceptual model. The results from multiple regression, path analysis, and Structural Equation Modeling (SEM were same. Thus, all hypotheses were supported by SPSS and SEM analyses. The findings of the study are discussed in detail.

  14. SUPPLIES COSTS: AN EXPLORATORY STUDY WITH APPLICATION OF MEASUREMENT MODEL OF LOGISTICS COSTS

    Directory of Open Access Journals (Sweden)

    Ana Paula Ferreira Alves

    2013-12-01

    Full Text Available One of the main reasons for the difficulty in adopting an integrated method of calculation of logistics costs is still a lack of adequate information about costs. The management of the supply chain and identify its costs can provide information for their managers, with regard to decision making, generating competitive advantage. Some models of calculating logistics costs are proposed by Uelze (1974, Dias (1996, Goldratt (2002, Christopher (2007, Castiglioni (2009 and Borba & Gibbon (2009, with little disclosure of the results. In this context, this study aims to evaluate the costs of supplies, applying a measurement model of logistics costs. Methodologically, the study characterized as exploratory. The model applied pointed, in original condition, that about R$ 2.5 million were being applied in the process of management of supplies, with replacement costs and storage imbalance. Upgrading the company's data, it is possible obtain a 52% reduction in costs to replace and store supplies. Thus, the cost model applied to logistical supplies showed feasibility of implementation, as well as providing information to assist in management and decision-making in logistics supply.

  15. Measurement, modeling, and analysis of nonmethane hydrocarbons and ozone in the southeast United States national parks

    Science.gov (United States)

    Kang, Daiwen

    In this research, the sources, distributions, transport, ozone formation potential, and biogenic emissions of VOCs are investigated focusing on three Southeast United States National Parks: Shenandoah National Park, Big Meadows site (SHEN), Great Smoky Mountains National Park at Cove Mountain (GRSM) and Mammoth Cave National Park (MACA). A detailed modeling analysis is conducted using the Multiscale Air Quality SImulation Platform (MAQSIP) focusing on nonmethane hydrocarbons and ozone characterized by high O3 surface concentrations. Nine emissions perturbation using the Multiscale Air Quality SImulation Platform (MAQSIP) focusing on nonmethane hydrocarbons and ozone characterized by high O 3 surface concentrations. In the observation-based analysis, source classification techniques based on correlation coefficient, chemical reactivity, and certain ratios were developed and applied to the data set. Anthropogenic VOCs from automobile exhaust dominate at Mammoth Cave National Park, and at Cove Mountain, Great Smoky Mountains National Park, while at Big Meadows, Shenandoah National Park, the source composition is complex and changed from 1995 to 1996. The dependence of isoprene concentrations on ambient temperatures is investigated, and similar regressional relationships are obtained for all three monitoring locations. Propylene-equivalent concentrations are calculated to account for differences in reaction rates between the OH and individual hydrocarbons, and to thereby estimate their relative contributions to ozone formation. Isoprene fluxes were also estimated for all these rural areas. Model predictions (base scenario) tend to give lower daily maximum O 3 concentrations than observations by 10 to 30%. Model predicted concentrations of lumped paraffin compounds are of the same order of magnitude as the observed values, while the observed concentrations for other species (isoprene, ethene, surrogate olefin, surrogate toluene, and surrogate xylene) are usually an

  16. Married with Children : A Collective Labor Supply Model with Detailed Time Use and Intrahousehold Expenditure Information

    NARCIS (Netherlands)

    Cherchye, L.J.H.; de Rock, B.; Vermeulen, F.M.P.

    2010-01-01

    We propose a collective labor supply model with household production that generalizes an original model of Blundell, Chiappori and Meghir (2005). In our model, adults' individual preferences do not only depend on own leisure and individual private consumption of market goods. They also depend on the

  17. ADDING SUPPLY-DRIVEN CONSUMPTION MAKES THE GHOSH MODEL EVEN MORE IMPLAUSIBLE

    NARCIS (Netherlands)

    Oosterhaven, Jan

    2012-01-01

    Guerra and Sancho (2011) argue that adding a supply-driven consumption function to the Ghosh model diminishes its implausibility in the case of centrally planned economies. Extending the Leontief model with a demand-driven consumption function does make that model more realistic. Extending the Ghosh

  18. A cost optimization model for 100% renewable residential energy supply systems

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2012-01-01

    's involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system costs. It has been successfully applied......The concept of net zero energy buildings (Net ZEB) has received increased attention throughout the last years. A well adapted and optimized design of the energy supply system is crucial for the performance of these buildings. To achieve this, a holistic approach is needed which accounts...... for the interdependencies between the different supply technologies as well as the construction energy of the installations, consumption profiles and on-site energy resource availability. This paper aims at developing such a model for the optimal sizing of renewable energy supply systems (RES) for residential Net ZEB...

  19. Coordination game model of co-opetition relationship on cluster supply chains

    Institute of Scientific and Technical Information of China (English)

    Zhou Min; Deng Feiqi; Wu Sai

    2008-01-01

    The research of cluster supply chains is a new direction and a hotspot of the industrial cluster theory. On the condition of the coordination game, the enterprises may be stuck on the non-efficient equilibrium status, which becomes an important problem that must be considered on cluster supply chains. A symmetrical coordination game model is constituted to describe the competition and cooperation relationship of the same-quality manufacturers on cluster supply chains. The methods of the non-cooperation game theory and the evolutionary game theory are respectively used to analyze the model, whose parameters' influences under each method are then compared. It can be concluded that the analysis of the evolutionary game theory is more realistic and practical. Finally, three approaches are considered to break away from being path-dependence locked-in non-efficient status during this coordination game evolutionary process, which provide the development of cluster supply chains with an effective forecasting and Pareto optimizing method.

  20. An automotive supply chain model for a demand-driven environment

    Directory of Open Access Journals (Sweden)

    Intaher M. Ambe

    2011-11-01

    Full Text Available The purpose of this article is to demonstrate the development of a supply chain model for the automotive industry that would respond to changing consumer demand. Now more than ever, businesses need to improve the efficiency of their supply chains in order to maintain a competitive advantage. The principles of lean manufacturing and just-intime (JIT inventory control that were renowned for helping companies like Toyota, Dell and Walmart to rise to the top of their respective industries are no longer adequate. Leading companies are applying new technologies and sophisticated analytics to make their supply chains more responsive to customer demand. This challenge is driven by fierce competition, fluctuating market demand and rising customer requirements that have led to customers becoming more demanding with increased preferences. The article is based on theoretical reviews and suggests guidelines for the implementation of an automotive supply chain model for a demand-driven environment.

  1. Back-Propagation Artificial Neural Networks for Water Supply Pipeline Model

    Institute of Scientific and Technical Information of China (English)

    朱东海; 张土乔; 毛根海

    2002-01-01

    Water supply pipelines are the lifelines of a city. When pipelines burst, the burst site is difficult to locate by traditional methods such as manual tools or only by watching. In this paper, the burst site was identified using back-propagation (BP) artificial neural networks (ANN). The study is based on an indoor urban water supply model experiment. The key to appling BP ANN is to optimize the ANN's topological structure and learning parameters. This paper presents the optimizing method for a 3-layer BP neural network's topological structure and its learning parameters-learning ratio and the momentum factor. The indoor water supply pipeline model experimental results show that BP ANNs can be used to locate the burst point in urban water supply systems. The topological structure and learning parameters were optimized using the experimental results.

  2. A stochastic inventory management model for a dual sourcing supply chain with disruptions

    Science.gov (United States)

    Iakovou, Eleftherios; Vlachos, Dimitrios; Xanthopoulos, Anastasios

    2010-03-01

    As companies continue to globalise their operations and outsource significant portion of their value chain activities, they often end up relying heavily on order replenishments from distant suppliers. The explosion in long-distance sourcing is exposing supply chains and shareholder value at ever increasing operational and disruption risks. It is well established, both in academia and in real-world business environments, that resource flexibility is an effective method for hedging against supply chain disruption risks. In this contextual framework, we propose a single period stochastic inventory decision-making model that could be employed for capturing the trade-off between inventory policies and disruption risks for an unreliable dual sourcing supply network for both the capacitated and uncapacitated cases. Through the developed model, we obtain some important managerial insights and evaluate the merit of contingency strategies in managing uncertain supply chains.

  3. Control Theory Concepts Applied to Retail Supply Chain: A System Dynamics Modeling Environment Study

    Directory of Open Access Journals (Sweden)

    Balaji Janamanchi

    2013-01-01

    Full Text Available Control theory concepts have been long used to successfully manage and optimize complex systems. Using system dynamics (SD modeling methodology, which is continuous deterministic simulation modeling methodology, we apply control theory concepts to develop a suitable performance functional (or objective function that optimizes the performance of a retail supply chain. The focus is to develop insights for inventory management to prevent stock-outs and unfilled orders and to fill customer orders at the lowest possible cost to supply chain partners under different scenarios, in a two-player supplier-retailer supply chain. Moderate levels of inventory, defining appropriate performance functional, appear to be crucial in choosing the right policies for managing retail supply chain systems. The study also demonstrated how multiple objectives can be combined in a single performance functional (or objective function by carefully assigning suitable weights to the components of objectives based on their priority and the existence of possible trade off opportunities.

  4. Hedging Rules for Water Supply Reservoir Based on the Model of Simulation and Optimization

    Directory of Open Access Journals (Sweden)

    Yi Ji

    2016-06-01

    Full Text Available This study proposes a hedging rule model which is composed of a two-period reservior operation model considering the damage depth and hedging rule parameter optimization model. The former solves hedging rules based on a given poriod’s water supply weighting factor and carryover storage target, while the latter optimization model is used to optimize the weighting factor and carryover storage target based on the hedging rules. The coupling model gives the optimal poriod’s water supply weighting factor and carryover storage target to guide release. The conclusions achieved from this study as follows: (1 the water supply weighting factor and carryover storage target have a direct impact on the three elements of the hedging rule; (2 parameters can guide reservoirs to supply water reasonably after optimization of the simulation and optimization model; and (3 in order to verify the utility of the hedging rule, the Heiquan reservoir is used as a case study and particle swarm optimization algorithm with a simulation model is adopted for optimizing the parameter. The results show that the proposed hedging rule can improve the operation performances of the water supply reservoir.

  5. Supply chain production model with preservation technology under fuzzy environment

    Directory of Open Access Journals (Sweden)

    S.R. Singh

    2014-06-01

    Full Text Available In this paper, an attempt is made to characterize the preservation technology for deteriorating items to reduce the deterioration rate. This model assumes a single producer and single supplier and formulates a production model with a time varying rate of deterioration rate. Here production and demand are treated as a fuzzy variables and total cost is minimized for both the crisp and fuzzy model. Shortage is allowed on the supplier’s part, which is partially backlogged. A solution procedure is presented to determine an optimal replenishment cycle and total cost per unit time, which is a convex function of preservation technology cost. Results have been validated with relevant example. In a way, the proposed model provides a unique theory to reduce the deterioration rate for the production model.

  6. An Inter-enterprise Workflow Model for Supply Chain and B2B E-commerce

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The goals of B2B electronic commerce and supply chain management system are to implement interoperability of independent enterprises, to smooth the information flow between them and to deploy business processes over multiple enterprises. The inherent characteristics of workflow system make it suitable to implement the cross organization management. This paper, firstly, proposes an inter-enterprises workflow model based on the agreement to support the construction of supply chain management system and B2B electronic commerce. This model has extended the standard workflow model. After that, an architecture which supports the model has been introduced, especially it details the structure and implementation of interfaces between enterprises.

  7. Controls on sequence development and preservation offshore Namibia: Implications for sequence stratigraphic models and hydrocarbon prediction

    Energy Technology Data Exchange (ETDEWEB)

    Bagguley, J.G. [Oxford Brookes Univ., Oxford (United Kingdom); Prosser, S. [Saga Petroleum, Sandvika (Norway)

    1996-12-31

    Regional seismic interpretation of the passive margin offshore Namibia has enabled a sequence stratigraphic framework to be established for this previously under-studied region. Within this framework potential hydrocarbon plays, for example the location of source, seal and reservoir rocks can be pinpointed. The history of sequence stratigraphic models suggests that the passive margin offshore Namibia should provide an ideal setting for applying and testing sequence stratigraphic concepts. Results from this study however suggest that alongside the documented controls in sequence stratigraphy (i.e. tectonics, eustacy and sediment flux), additional factors act to influence sequence development and preservation along this margin. Detailed seismic interpretation of the post rift section of the Namibian margin has led to the identification of a member of erosional and depositional events; for example, charmers, canyons and slumps. Seismic facies analysis allows causative mechanisms to be inferred for the different geometries observed. In addition, the recognition of characteristic seismic facies enables reservoir and non-reservoir targets to be identified, thus aiding the prediction of potential hydrocarbon plays. Backstripping studies provide further information as to the evolution of the Namibian margin. For example, estimates can be made regarding changes in the rates of tectonics and sedimentation and the relative importance of these factors on the development of the margin can be assessed.

  8. Controls on sequence development and preservation offshore Namibia: Implications for sequence stratigraphic models and hydrocarbon prediction

    Energy Technology Data Exchange (ETDEWEB)

    Bagguley, J.G. (Oxford Brookes Univ., Oxford (United Kingdom)); Prosser, S. (Saga Petroleum, Sandvika (Norway))

    1996-01-01

    Regional seismic interpretation of the passive margin offshore Namibia has enabled a sequence stratigraphic framework to be established for this previously under-studied region. Within this framework potential hydrocarbon plays, for example the location of source, seal and reservoir rocks can be pinpointed. The history of sequence stratigraphic models suggests that the passive margin offshore Namibia should provide an ideal setting for applying and testing sequence stratigraphic concepts. Results from this study however suggest that alongside the documented controls in sequence stratigraphy (i.e. tectonics, eustacy and sediment flux), additional factors act to influence sequence development and preservation along this margin. Detailed seismic interpretation of the post rift section of the Namibian margin has led to the identification of a member of erosional and depositional events; for example, charmers, canyons and slumps. Seismic facies analysis allows causative mechanisms to be inferred for the different geometries observed. In addition, the recognition of characteristic seismic facies enables reservoir and non-reservoir targets to be identified, thus aiding the prediction of potential hydrocarbon plays. Backstripping studies provide further information as to the evolution of the Namibian margin. For example, estimates can be made regarding changes in the rates of tectonics and sedimentation and the relative importance of these factors on the development of the margin can be assessed.

  9. A new HYSYS model for underground gasification of hydrocarbons under hydrothermal conditions

    KAUST Repository

    Alshammari, Y.M.

    2014-08-01

    A new subsurface process model was developed using the ASPEN HYSYS simulation environment to analyse the process energy and gasification efficiency at steady-state equilibrium conditions. Injection and production wells were simulated using the HYSYS pipe flow utilities which makes use of the Beggs and Brill flow correlation applicable for vertical pipes. The downhole reservoir hydrothermal reactions were assumed to be in equilibrium, and hence, the Gibbs reactor was used. It was found that high W/C ratios and low O/C ratios are required to maximise gasification efficiency at a constant hydrocarbon feed flowrate, while the opposite is true for the energy efficiency. This occurs due to the dependence of process energy efficiency on the gas pressure and temperature at surface, while the gasification efficiency depends on the gas composition which is determined by the reservoir reaction conditions which affects production distribution. Another effect of paramount importance is the increase in reservoir production rate which was found to directly enhance both energy and gasification efficiency showing conditions where the both efficiencies are theoretically maximised. Results open new routes for techno-economic assessment of commercial implementation of underground gasification of hydrocarbons. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  10. Performance metric optimization advocates CPFR in supply chains: A system dynamics model based study

    OpenAIRE

    Balaji Janamanchi; James R. Burns

    2016-01-01

    Background: Supply Chain partners often find themselves in rather helpless positions, unable to improve their firm’s performance and profitability because their partners although willing to share production information do not fully collaborate in tackling customer order variations as they don’t seem to appreciate the benefits of such collaboration. Methods: We use a two-player (supplier-manufacturer) System Dynamics model to study the dynamics to assess the impact and usefulness of supply cha...

  11. HABIT FORMATION AND PREFERENCE CHANGE IN A TWOSECTOR GROWTH MODEL WITH ELASTIC LABOR SUPPLY

    OpenAIRE

    Zhang, Wei-Bin

    2013-01-01

    The purpose of this study is to develop a two sector growth model with elastic labor supply and preference change. The preference change is influenced by the ideas of time preference and habit formation in the Ramsey-type growth theory. This study deals with interactions among capital accumulation, economic structure, labor supply, labor and capital distribution, habit formation and time preference in an integrated framework. The paper simulates the three autonomous nonlinear differential equ...

  12. Removal of polycyclic aromatic hydrocarbons in soil spiked with model mixtures of petroleum hydrocarbons and heterocycles using biosurfactants from Rhodococcus ruber IEGM 231.

    Science.gov (United States)

    Ivshina, Irina; Kostina, Ludmila; Krivoruchko, Anastasiya; Kuyukina, Maria; Peshkur, Tatyana; Anderson, Peter; Cunningham, Colin

    2016-07-15

    Removal of polycyclic aromatic hydrocarbons (PAHs) in soil using biosurfactants (BS) produced by Rhodococcus ruber IEGM 231 was studied in soil columns spiked with model mixtures of major petroleum constituents. A crystalline mixture of single PAHs (0.63g/kg), a crystalline mixture of PAHs (0.63g/kg) and polycyclic aromatic sulfur heterocycles (PASHs), and an artificially synthesized non-aqueous phase liquid (NAPL) containing PAHs (3.00g/kg) dissolved in alkanes C10-C19 were used for spiking. Percentage of PAH removal with BS varied from 16 to 69%. Washing activities of BS were 2.5 times greater than those of synthetic surfactant Tween 60 in NAPL-spiked soil and similar to Tween 60 in crystalline-spiked soil. At the same time, amounts of removed PAHs were equal and consisted of 0.3-0.5g/kg dry soil regardless the chemical pattern of a model mixture of petroleum hydrocarbons and heterocycles used for spiking. UV spectra for soil before and after BS treatment were obtained and their applicability for differentiated analysis of PAH and PASH concentration changes in remediated soil was shown. The ratios A254nm/A288nm revealed that BS increased biotreatability of PAH-contaminated soils.

  13. A continuous labour supply model in microsimulation: a life-cycle modelling approach with heterogeneity and uncertainty extension.

    Directory of Open Access Journals (Sweden)

    Jinjing Li

    Full Text Available This paper advances a structural inter-temporal model of labour supply that is able to simulate the dynamics of labour supply in a continuous setting and addresses two main drawbacks of most existing models. The first limitation is the inability to incorporate individual heterogeneity as every agent is sharing the same parameters of the utility function. The second one is the strong assumption that individuals make decisions in a world of perfect certainty. Essentially, this paper offers an extension of marginal-utility-of-wealth-constant labour supply functions known as "Frisch functions" under certainty and uncertainty with homogenous and heterogeneous preferences. The lifetime models based on the fixed effect vector decomposition yield the most stable simulation results, under both certain and uncertain future wage assumptions. Due to its improved accuracy and stability, this lifetime labour supply model is particularly suitable for enhancing the performance of the life cycle simulation models, thus providing a better reference for policymaking.

  14. A continuous labour supply model in microsimulation: a life-cycle modelling approach with heterogeneity and uncertainty extension.

    Science.gov (United States)

    Li, Jinjing; Sologon, Denisa Maria

    2014-01-01

    This paper advances a structural inter-temporal model of labour supply that is able to simulate the dynamics of labour supply in a continuous setting and addresses two main drawbacks of most existing models. The first limitation is the inability to incorporate individual heterogeneity as every agent is sharing the same parameters of the utility function. The second one is the strong assumption that individuals make decisions in a world of perfect certainty. Essentially, this paper offers an extension of marginal-utility-of-wealth-constant labour supply functions known as "Frisch functions" under certainty and uncertainty with homogenous and heterogeneous preferences. The lifetime models based on the fixed effect vector decomposition yield the most stable simulation results, under both certain and uncertain future wage assumptions. Due to its improved accuracy and stability, this lifetime labour supply model is particularly suitable for enhancing the performance of the life cycle simulation models, thus providing a better reference for policymaking.

  15. A genetic algorithm for solving supply chain network design model

    Science.gov (United States)

    Firoozi, Z.; Ismail, N.; Ariafar, S. H.; Tang, S. H.; Ariffin, M. K. M. A.

    2013-09-01

    Network design is by nature costly and optimization models play significant role in reducing the unnecessary cost components of a distribution network. This study proposes a genetic algorithm to solve a distribution network design model. The structure of the chromosome in the proposed algorithm is defined in a novel way that in addition to producing feasible solutions, it also reduces the computational complexity of the algorithm. Computational results are presented to show the algorithm performance.

  16. A Supply and Demand Model of the College Admissions Problem

    OpenAIRE

    2009-01-01

    We develop the first Bayesian model of decentralized college admissions, with heterogeneous students, costly portfolio applications, and noisy college evaluations. Students face a nontrivial portfolio choice, and colleges choose admissions standards that act like market-clearing prices. We derive the two college model equilibrium, deriving a “law of demand”. Surprisingly, the worse college might impose higher standards, and weaker students sometimes apply more aggressively. The lesser coll...

  17. MODEL DINAMIS SUPPLY CHAIN BERAS BERKELANJUTAN DALAM UPAYA KETAHANAN PANGAN NASIONAL

    Directory of Open Access Journals (Sweden)

    Akhmad Mahbubi

    2014-09-01

    Full Text Available ABSTRACTThis study was aimed to 1 identify the basic system of rice supply chain, 2 design a conceptual system and formulate a model of rice supply chain to achieve rice food security and 3 identify the sustainability behavior of the rice supply chain systems for the next 30 years from the aspects of economical revenue, social welfare and environment. Dynamic model was used to analyze the data. Referring to a variety of technical indicators achievement in the blueprint of national food security, several policy scenarios were used in the analysis of the behavior of rice supply chain systems until 2042 in economical revenue, social welfare and the environment aspects. The results of this study showed that the self-sufficiency of rice will continue until 2042 (the end of the study’s simulation. It also showed that in the long run, national rice food security will be disrupted if the government does not stop the conversion of agricultural land. Therefore, the government needs to issue a policy related to the conversion of agricultural land, especially paddy fields for infrastructure development.Keywords: rice, sustainable, food security, dynamic models, supply chainABSTRAKTujuan Penelitian adalah 1 mengidentifikasi sistem dasar supply chain beras, 2 menyusun konseptual sistem dan formulasi model supply chain beras untuk pencapaian ketahanan pangan nasional, serta 3 mengetahui perilaku sistem supply chain beras untuk 30 tahun kedepan tetap berkelanjutan dilihat dari aspek pendapatan ekonomi, sosial dan lingkungan. Analisis data menggunakan model dinamis. Beberapa skenario dalam analisis perilaku supply chain beras sampai tahun 2042 dilihat dari aspek pendapatan ekonomi, sosial dan lingkungan mengacu pada indikator pencapaian dalam blue print ketahanan pangan nasional. Hasil penelitian ini, swasembada pangan beras akan berkelanjutan sampai 2042 (akhir dari simulasi penelitian ini. Dalam jangka panjang, ketahanan pangan beras nasional akan terganggu

  18. Development and implementation of integrated biomass supply analysis and logistics model (IBSAL)

    Energy Technology Data Exchange (ETDEWEB)

    Sokhansanj, Shahab; Turhollow, Anthony F. [Oak Ridge National Laboratory, Oak Ridge, TN (United States). Environmental Sciences Division; Kumar, Amit [University of Alberta, Edmonton, AB (Canada). Department of Mechanical Engineering

    2006-10-15

    This paper describes the framework development of a dynamic integrated biomass supply analysis and logistics model (IBSAL) to simulate the collection, storage, and transport operations for supplying agricultural biomass to a biorefinery. The model consists of time dependent events representing the working rate of equipment and queues representing the capacity of storage structures. The discrete event and queues are inter-connected to represent the entire network of material flow from field to a biorefinery. Weather conditions including rain and snow influence the moisture content and the dry matter loss of biomass through the supply chain and are included in the model. The model is developed using an object oriented high level simulation language EXTEND(TM). A case of corn stover collection and transport scenario using baling system is described. (author)

  19. Lifecycle Agile Supply Chain Modeling for Customized and ComplicatedProducts Based on CPC

    Institute of Scientific and Technical Information of China (English)

    景旭文; 赵良才; 张庆奎

    2004-01-01

    Customized and complicated products are usually high-priced with a long lifecycle. They provide customers with some maintenance capacity. While a great deal of research on product lifecycle design has been carried out, studies on the lifecycle agile supply chain (LASC) are less covered. The LASC functions, management goals, mathematical expressions and overall descriptions of the information model are discussed in this paper. The product lifecycle configuration is a core of the LASC information flow. The structure,function, manufacturing and maintenance configuration views are generated by coordinated lifecycle design. Purchase view 1 in the manufacturing phase is formed by combining the manufacturing configuration with B2B supply model, while purchase view 2 in the maintenance phase is formed by combining maintenance configuration with B2C supply model, serving the production and repair planning respectively. A prototype system has included some basic functions of this model.

  20. A Multi-parameter Model for Effective Configuration of Supply Chains

    Directory of Open Access Journals (Sweden)

    Alfredo Lambiase

    2015-12-01

    Full Text Available In this paper, a mathematical model for the strategic planning and design of supply chains in the globalization context is proposed. A multi-objective function is used to address decisions about capacity sizing, sourcing, and facility location, with the scope of maximizing supply chain profits. The model is dynamic and is applied to a multi-echelon, multi-facility and multi-product supply chain in hypotheses of delocalization. The model is characterized by the specific attention given to cost, revenue and financial factor modelling, which has been obtained by means of an activity-based approach and the inclusion of two drivers that are usually neglected in the literature: energy and labour. The model’s applicability and flexibility have been proved via a scenario analysis in which 12 different scenarios were implemented to reproduce the behaviour of major industries.

  1. Supplier Selection in Three Echelon Supply Chain & Vendor Managed Inventory Model Under Price Dependent Demand Condition

    Directory of Open Access Journals (Sweden)

    Mohammad Sohrabi

    2016-02-01

    Full Text Available This paper, considers the supplier selection in three echelon supply chain with Vendor Managed Inventory (VMI strategy under price dependent demand condition. As there is a lack of study on the supplier selection in VMI literature, this paper presents a VMI model in supply chain including multi supplier, one distributer and multi retailer that distributer selects suppliers. Two class models (traditional vs. VMI are presented and we compare them to study the impact of VMI on supply chain and supplier selection. As the proposed model is a NP-hard problem, a meta-heuristics namely Harmony Search is employed to optimize the proposed models. We show that how the VMI system can effect on supplier selection and can change the set of selected suppliers. Finally the conclusion and further studies are presented

  2. Modeling polycyclic aromatic hydrocarbon bioaccumulation and metabolism in time-variable early life-stage exposures.

    Science.gov (United States)

    Mathew, Rooni; McGrath, Joy A; Di Toro, Dominic M

    2008-07-01

    Recent laboratory investigations into the bioaccumulation and toxicity of polycyclic aromatic hydrocarbons (PAH) have focused on low-level, time-variable exposures to early life-stage fish. Polycyclic aromatic hydrocarbon body-burden residues reported in these studies were lower than critical body-burden residues predicted by the target lipid model (TLM). To understand this discrepancy, a time-variable uptake and depuration model of PAH bioaccumulation was developed. Kinetic constants were fit using measured exposure and tissue concentrations. The resulting lipid-water partition coefficients (K(LW)) were uncorrelated with the octanol-water partition coefficient (K(OW))--a qualitatively unrealistic finding considering that numerous studies have reported a positive correlation between the two. Because PAHs are known to be metabolized, the comparison of K(LW) with K(OW) suggests that metabolism may be occurring in early life-stage fish. Therefore, the uptake and depuration model was modified to include metabolism while assuming linearity of K(LW) with K(OW). Calculated metabolism rates were positively correlated with K(OW)--a finding qualitatively similar to those of other studies. The present study provides a reasonable explanation for the discrepancy between the TLM predictions and the measured toxic effect levels. Given the time-variable exposure concentrations, the maximum measured body burdens used to relate to toxic effects may be underestimated. In addition, the maximum body burden of parent PAH plus metabolites may be a better measure in relating tissue concentrations to toxic effects. Incorporating these refinements in relating body burdens to toxic effects may result in a better comparison between TLM predictions and measured effect levels.

  3. Developing a Model for Agility in Health Humanitarian Supply Chains Using Factor Analysis: Evidence From Iran

    Directory of Open Access Journals (Sweden)

    Jahanbani

    2014-10-01

    Full Text Available Background Since 2000, increase in frequency and severity of natural disasters has necessitate designing an agile relief supply chain to help to affected people. Objectives This study aimed to develop an agile model for supply chains with emphasis on health services in Iranian relief organizations. Materials and Methods This was a descriptive-comparative study. In order to design the conceptual model, agility patterns of supply chains were reviewed in a comparative study. Moreover, a questionnaire was prepared to examine construct (model validation. The validity of questionnaire was confirmed by the judgment of experts and its reliability was ensured by test-retest method with scale of 0.99, and Cronbach's alpha of 0.98. All data were analyzed through factor analyses by SPSS 16 and LISREL 8.53. Results Responsiveness, effectiveness, and flexibility with eigenvalue of 2.628 were identified as the main aspects of agility in humanitarian health supply chains. The components of visibility, reactivity, and speed were identified as components of responsiveness. Quality, reliability, and completeness were identified as components of effectiveness. Volume, delivery, mix, and product were known as components of flexibility. Conclusions Findings confirmed agility dimensions and relationships between them in a model that can be considered as a comprehensive and appropriate model in the establishment, promotion, and evaluation of relief supply chains by policy-makers and authorities of Red Crescent Society and Medical Emergencies.

  4. A Core Model for Parts Suppliers Selecting Method in Manufacturing Supply Chain

    Directory of Open Access Journals (Sweden)

    Guorong Chen

    2015-01-01

    Full Text Available Service-oriented manufacturing is the new development of manufacturing systems, and manufacturing supply chain service is also an important part of the service-oriented manufacturing systems; hence, the optimal selection of parts suppliers becomes one of key problems in the supply chain system. Complex network theories made a rapid progress in recent years, but the classical models such as BA model and WS model can not resolve the widespread problems of manufacturing supply chain, such as the repeated attachment of edge and fixed number of vertices, but edges increased with preferential connectivity, and flexible edges’ probability. A core model is proposed to resolve the problem in the paper: it maps the parts supply relationship as a repeatable core; a vertex’s probability distribution function integrating the edge’s rate and vertex’s degree is put forward; some simulations, such as the growth of core, the degree distribution characteristics, and the impacting of parameter, are carried out in our experiments, and the case study is set also. The paper proposed a novel model to analyze the manufacturing supply chain system from the insights of complex network.

  5. A Four-Type Decision-Variable MINLP Model for a Supply Chain Network Design

    Directory of Open Access Journals (Sweden)

    M. M. Monteiro

    2010-01-01

    Full Text Available We propose a mixed integer nonlinear programming model for the design of a one-period planning horizon supply chain with integrated and flexible decisions on location of plants and of warehouses, on levels of production and of inventory, and on transportation models, considering stochastic demand and the ABC classification for finished goods, which is an NP-hard industrial engineering optimization problem. Furthermore, computational implementation of the proposed model is presented through the direct application of the outer approximation algorithm on some randomly generated supply chain data.

  6. A Two-Layered Model for Dynamic Supply Chain Management Considering Transportation Constraint

    Science.gov (United States)

    Tanimizu, Yoshitaka; Harada, Kana; Ozawa, Chisato; Iwamura, Koji; Sugimura, Nobuhiro

    This research proposes a two-layered model for dynamic supply chain management considering transportation constraint. The model provides a method for suppliers to estimate suitable prices and delivery times of products based on not only production schedules but also transportation plans in consideration of constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the model. The prototype system is available to determine suitable shipping times and loading capacities of transportation vehicles.

  7. Technoeconomic assumptions adopted for the development of a long-term electricity supply model for Cyprus.

    Science.gov (United States)

    Taliotis, Constantinos; Taibi, Emanuele; Howells, Mark; Rogner, Holger; Bazilian, Morgan; Welsch, Manuel

    2017-10-01

    The generation mix of Cyprus has been dominated by oil products for decades. In order to conform with European Union and international legislation, a transformation of the supply system is called for. Energy system models can facilitate energy planning into the future, but a large volume of data is required to populate such models. The present data article provides information on key modelling assumptions and input data adopted with the aim of representing the electricity supply system of Cyprus in a separate research article. Data in regards to renewable energy technoeconomic characteristics and investment cost projections, fossil fuel price projections, storage technology characteristics and system operation assumptions are described in this article.

  8. Modelling a sector undergoing structural change: The case of Danish energy supply

    DEFF Research Database (Denmark)

    Klinge Jacobsen, Henrik

    2000-01-01

    been linked to a macroeconometric model of the Danish economy. It is argued that analysing sectors that undergo radical changes, for example, the energy supply sector should be undertaken by using a model that describes the technological and organisational changes in production along with implications......This paper examines structural change in the power and heat producing sector (energy supply) and its implications for the economy. An integrated approach is used to describe the interactions between this sector and the rest of the economy. Thus, a very detailed model of the sector for Denmark has...

  9. A Hybrid Method for Modeling and Solving Supply Chain Optimization Problems with Soft and Logical Constraints

    Directory of Open Access Journals (Sweden)

    Paweł Sitek

    2016-01-01

    Full Text Available This paper presents a hybrid method for modeling and solving supply chain optimization problems with soft, hard, and logical constraints. Ability to implement soft and logical constraints is a very important functionality for supply chain optimization models. Such constraints are particularly useful for modeling problems resulting from commercial agreements, contracts, competition, technology, safety, and environmental conditions. Two programming and solving environments, mathematical programming (MP and constraint logic programming (CLP, were combined in the hybrid method. This integration, hybridization, and the adequate multidimensional transformation of the problem (as a presolving method helped to substantially reduce the search space of combinatorial models for supply chain optimization problems. The operation research MP and declarative CLP, where constraints are modeled in different ways and different solving procedures are implemented, were linked together to use the strengths of both. This approach is particularly important for the decision and combinatorial optimization models with the objective function and constraints, there are many decision variables, and these are summed (common in manufacturing, supply chain management, project management, and logistic problems. The ECLiPSe system with Eplex library was proposed to implement a hybrid method. Additionally, the proposed hybrid transformed model is compared with the MILP-Mixed Integer Linear Programming model on the same data instances. For illustrative models, its use allowed finding optimal solutions eight to one hundred times faster and reducing the size of the combinatorial problem to a significant extent.

  10. A robust optimization model for blood supply chain in emergency situations

    Directory of Open Access Journals (Sweden)

    Meysam Fereiduni

    2016-09-01

    Full Text Available In this paper, a multi-period model for blood supply chain in emergency situation is presented to optimize decisions related to locate blood facilities and distribute blood products after natural disasters. In disastrous situations, uncertainty is an inseparable part of humanitarian logistics and blood supply chain as well. This paper proposes a robust network to capture the uncertain nature of blood supply chain during and after disasters. This study considers donor points, blood facilities, processing and testing labs, and hospitals as the components of blood supply chain. In addition, this paper makes location and allocation decisions for multiple post disaster periods through real data. The study compares the performances of “p-robust optimization” approach and “robust optimization” approach and the results are discussed.

  11. APLIKASI MODEL HOUSE OF RISK (HOR UNTUK MITIGASI RISIKO PADA SUPPLY CHAIN BAHAN BAKU KULIT

    Directory of Open Access Journals (Sweden)

    Bayu Rizki Kristanto

    2014-12-01

    Full Text Available Dalam aktivitas supply chain selalu berpotensi untuk timbul risiko, oleh sebab itu manajemen risiko sangat diperlukan untuk penanganan risiko. Pada perusahaan yang memproduksi sepatu kulit seperti PT. Karyamitra Budisentosa, dalam aktivitas supply chain bahan baku kulit memiliki peluang untuk timbul risiko. Oleh sebab itu perlu dilakukan analisa risiko dan rancangan aksi mitigasi, untuk memitigasi risiko atau gangguan yang berpeluang timbul pada supply chain bahan baku kulit tersebut. Penelitian ini dilakukan dengan menggunakan model house of risk yang terdiri dari 2 fase. Fase pertama yaitu pengidentifikasian risiko dan agen risiko, yang kemudian dilakukan pengukuran tingkat severity dan occurance serta perhitungan nilai aggregate risk priority (ARP. Fase kedua yaitu penanganan risiko. Setelah dilakukan penelitian diperoleh hasil bahwa terdapat 27 kejadian risiko dan 52 agen risiko. Terdapat 6 aksi mitigasi yang dapat digunakan, dengan harapan mampu memitigasi risiko pada supply chain bahan baku kulit.

  12. The spread model of food safety risk under the supply-demand disturbance.

    Science.gov (United States)

    Wang, Jining; Chen, Tingqiang

    2016-01-01

    In this paper, based on the imbalance of the supply-demand relationship of food, we design a spreading model of food safety risk, which is about from food producers to consumers in the food supply chain. We use theoretical analysis and numerical simulation to describe the supply-demand relationship and government supervision behaviors' influence on the risk spread of food safety and the behaviors of the food producers and the food retailers. We also analyze the influence of the awareness of consumer rights protection and the level of legal protection of consumer rights on the risk spread of food safety. This model contributes to the explicit investigation of the influence relationship among supply-demand factors, the regulation behavioral choice of government, the behavioral choice of food supply chain members and food safety risk spread. And this paper provides a new viewpoint for considering food safety risk spread in the food supply chain, which has a great reference for food safety management.

  13. Modeling vibrational resonance in linear hydrocarbon chain with a mixed quantum-classical method.

    Science.gov (United States)

    Gelman, David; Schwartz, Steven D

    2009-04-07

    The quantum dynamics of a vibrational excitation in a linear hydrocarbon model system is studied with a new mixed quantum-classical method. The method is suited to treat many-body systems consisting of a low dimensional quantum primary part coupled to a classical bath. The dynamics of the primary part is governed by the quantum corrected propagator, with the corrections defined in terms of matrix elements of zeroth order propagators. The corrections are taken to the classical limit by introducing the frozen Gaussian approximation for the bath degrees of freedom. The ability of the method to describe dynamics of multidimensional systems has been tested. The results obtained by the method have been compared to previous quantum simulations performed with the quasiadiabatic path integral method.

  14. Applying the International Medical Graduate Program Model to Alleviate the Supply Shortage of Accounting Doctoral Faculty

    Science.gov (United States)

    HassabElnaby, Hassan R.; Dobrzykowski, David D.; Tran, Oanh Thikie

    2012-01-01

    Accounting has been faced with a severe shortage in the supply of qualified doctoral faculty. Drawing upon the international mobility of foreign scholars and the spirit of the international medical graduate program, this article suggests a model to fill the demand in accounting doctoral faculty. The underlying assumption of the suggested model is…

  15. An Improved Inventory Control Model for the Brazilian Navy Supply System

    Science.gov (United States)

    2001-12-01

    Portuguese Centro de Controle de Inventario da Marinha, the Brazilian Navy Inventory Control Point (ICP) developed an empirical model called SPAADA...NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS Approved for public release; distribution is unlimited AN IMPROVED INVENTORY CONTROL ...AN IMPROVED INVENTORY CONTROL MODEL FOR THE BRAZILIAN NAVY SUPPLY SYSTEM Contract Number Grant Number Program Element Number Author(s) Moreira

  16. Modeling plan-form deltaic response to changes in fluvial sediment supply

    NARCIS (Netherlands)

    Nienhuis, J.H.; Ashton, A.D.; Roos, P.C.; Hulscher, S.J.M.H.; Giosan, L.; Kranenburg, W.M.; Horstman, E.M.; Wijnberg, K.M.

    2012-01-01

    This study focuses on the effects of changes in fluvial sediment supply on the plan-form shape of wave-dominated deltas. We apply a one-line numerical shoreline model to calculate shoreline evolution after (I) elimination and (II) time-periodic variation of fluvial input. Model results suggest four

  17. Assessing the polycyclic aromatic hydrocarbon (PAH) pollution of urban stormwater runoff: a dynamic modeling approach.

    Science.gov (United States)

    Zheng, Yi; Lin, Zhongrong; Li, Hao; Ge, Yan; Zhang, Wei; Ye, Youbin; Wang, Xuejun

    2014-05-15

    Urban stormwater runoff delivers a significant amount of polycyclic aromatic hydrocarbons (PAHs), mostly of atmospheric origin, to receiving water bodies. The PAH pollution of urban stormwater runoff poses serious risk to aquatic life and human health, but has been overlooked by environmental modeling and management. This study proposed a dynamic modeling approach for assessing the PAH pollution and its associated environmental risk. A variable time-step model was developed to simulate the continuous cycles of pollutant buildup and washoff. To reflect the complex interaction among different environmental media (i.e. atmosphere, dust and stormwater), the dependence of the pollution level on antecedent weather conditions was investigated and embodied in the model. Long-term simulations of the model can be efficiently performed, and probabilistic features of the pollution level and its risk can be easily determined. The applicability of this approach and its value to environmental management was demonstrated by a case study in Beijing, China. The results showed that Beijing's PAH pollution of road runoff is relatively severe, and its associated risk exhibits notable seasonal variation. The current sweeping practice is effective in mitigating the pollution, but the effectiveness is both weather-dependent and compound-dependent. The proposed modeling approach can help identify critical timing and major pollutants for monitoring, assessing and controlling efforts to be focused on. The approach is extendable to other urban areas, as well as to other contaminants with similar fate and transport as PAHs.

  18. A minimal model for stabilization of biomolecules by hydrocarbon cross-linking

    Science.gov (United States)

    Hamacher, K.; Hübsch, A.; McCammon, J. A.

    2006-04-01

    Programmed cell death regulating protein motifs play an essential role in the development of an organism, its immune response, and disease-related cellular mechanisms. Among those motifs the BH3 domain of the BCL-2 family is found to be of crucial importance. Recent experiments showed how the isolated, otherwise unstructured BH3 peptide can be modified by a hydrocarbon linkage to regain function. We parametrized a reduced, dynamic model for the stability effects of such covalent cross-linking and confirmed that the model reproduces the reinforcement of the structural stability of the BH3 motif by cross-linking. We show that an analytically solvable model for thermostability around the native state is not capable of reproducing the stabilization effect. This points to the crucial importance of the peptide dynamics and the fluctuations neglected in the analytic model for the cross-linking system to function properly. This conclusion is supported by a thorough analysis of a simulated Gō model. The resulting model is suitable for rational design of generic cross-linking systems in silicio.

  19. A Case Study Using Modeling and Simulation to Predict Logistics Supply Chain Issues

    Science.gov (United States)

    Tucker, David A.

    2007-01-01

    Optimization of critical supply chains to deliver thousands of parts, materials, sub-assemblies, and vehicle structures as needed is vital to the success of the Constellation Program. Thorough analysis needs to be performed on the integrated supply chain processes to plan, source, make, deliver, and return critical items efficiently. Process modeling provides simulation technology-based, predictive solutions for supply chain problems which enable decision makers to reduce costs, accelerate cycle time and improve business performance. For example, United Space Alliance, LLC utilized this approach in late 2006 to build simulation models that recreated shuttle orbiter thruster failures and predicted the potential impact of thruster removals on logistics spare assets. The main objective was the early identification of possible problems in providing thruster spares for the remainder of the Shuttle Flight Manifest. After extensive analysis the model results were used to quantify potential problems and led to improvement actions in the supply chain. Similarly the proper modeling and analysis of Constellation parts, materials, operations, and information flows will help ensure the efficiency of the critical logistics supply chains and the overall success of the program.

  20. Supply chain single vendor – Single buyer inventory model with price-dependent demand

    Directory of Open Access Journals (Sweden)

    Mona Ahmadi Rad

    2014-09-01

    Full Text Available Purpose: The aim of this article is developing an integrated production-inventory-marketing model for a two-stage supply chain. The demand rate is considered as the Iso-elastic decreasing function of the selling price.  The main research goal of the article is to obtain the optimal values of the selling price, order quantity and number of shipments for the proposed model under independent and also joint optimization. In addition, the effects of the model’s parameters on the optimal solution are investigated. Design/methodology/approach: Mathematical modeling is used to obtain the joint total profit function of the supply chain. Then, the iterative solution algorithm is presented to solve the model and determine the optimal solution. Findings and Originality/value: It is observed that under joint optimization, the demand rate and the supply chain’s profit are higher than their values under independent optimization, especially for the more price sensitive demand. Therefore, coordination between the buyer and the vendor is advantageous for the supply chain.  On the other hand, joint optimization will be less beneficial when there isn’t a significant difference between the buyer’s and the vendor’s holding costs. Originality/value: The contribution of the article is determining the ordering and pricing policy jointly in the supply chain, which contains one vendor and one buyer while the demand rate is the Iso-elastic function of the selling price.

  1. Modeling biogeochemical processes of phosphorus for global food supply.

    Science.gov (United States)

    Dumas, Marion; Frossard, Emmanuel; Scholz, Roland W

    2011-08-01

    Harvests of crops, their trade and consumption, soil erosion, fertilization and recycling of organic waste generate fluxes of phosphorus in and out of the soil that continuously change the worldwide spatial distribution of total phosphorus in arable soils. Furthermore, due to variability in the properties of the virgin soils and the different histories of agricultural practices, on a planetary scale, the distribution of total soil phosphorus is very heterogeneous. There are two key relationships that determine how this distribution and its change over time affect crop yields. One is the relationship between total soil phosphorus and bioavailable soil phosphorus and the second is the relationship between bioavailable soil phosphorus and yields. Both of these depend on environmental variables such as soil properties and climate. We propose a model in which these relationships are described probabilistically and integrated with the dynamic feedbacks of P cycling in the human ecosystem. The model we propose is a first step towards evaluating the large-scale effects of different nutrient management scenarios. One application of particular interest is to evaluate the vulnerability of different regions to an increased scarcity in P mineral fertilizers. Another is to evaluate different regions' deficiency in total soil phosphorus compared with the level at which they could sustain their maximum potential yield without external mineral inputs of phosphorus but solely by recycling organic matter to close the nutrient cycle.

  2. Example models of building trust in supply chains of metalurgical enterprises

    Directory of Open Access Journals (Sweden)

    B. Gajdzik

    2012-10-01

    Full Text Available The article is an introduction to the notion of building trust in supply chains. Foreign publishers offer many articles connected with trust and some of the most important ones were quoted in this article. In business world there are models based on trust of the companies which are connected with one another and such models are very popular. Trust becomes the key link in the organisation of supply chains. It is one of the basic mechanisms of action co-ordination which provides the correctness of functioning in the whole chain. The growth of importance of trust between the links of the chain is also observed in metallurgy sector. For the purpose of this publication example models of supply chains structures were constructed in which relationships are based on mutual trust with characteristics of the metallurgical sector taken into account.

  3. A decision model for cost effective design of biomass based green energy supply chains.

    Science.gov (United States)

    Yılmaz Balaman, Şebnem; Selim, Hasan

    2015-09-01

    The core driver of this study is to deal with the design of anaerobic digestion based biomass to energy supply chains in a cost effective manner. In this concern, a decision model is developed. The model is based on fuzzy multi objective decision making in order to simultaneously optimize multiple economic objectives and tackle the inherent uncertainties in the parameters and decision makers' aspiration levels for the goals. The viability of the decision model is explored with computational experiments on a real-world biomass to energy supply chain and further analyses are performed to observe the effects of different conditions. To this aim, scenario analyses are conducted to investigate the effects of energy crop utilization and operational costs on supply chain structure and performance measures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Simulation-optimization model for production planning in the blood supply chain.

    Science.gov (United States)

    Osorio, Andres F; Brailsford, Sally C; Smith, Honora K; Forero-Matiz, Sonia P; Camacho-Rodríguez, Bernardo A

    2016-06-04

    Production planning in the blood supply chain is a challenging task. Many complex factors such as uncertain supply and demand, blood group proportions, shelf life constraints and different collection and production methods have to be taken into account, and thus advanced methodologies are required for decision making. This paper presents an integrated simulation-optimization model to support both strategic and operational decisions in production planning. Discrete-event simulation is used to represent the flows through the supply chain, incorporating collection, production, storing and distribution. On the other hand, an integer linear optimization model running over a rolling planning horizon is used to support daily decisions, such as the required number of donors, collection methods and production planning. This approach is evaluated using real data from a blood center in Colombia. The results show that, using the proposed model, key indicators such as shortages, outdated units, donors required and cost are improved.

  5. Burial history and kinetic modeling for hydrocarbon generation, Part II: Applying the Galo model to Saharan basins

    Energy Technology Data Exchange (ETDEWEB)

    Markhous, M.; Galushkin, Y. [Moscow State Univ. (Russian Federation); Lopatin, N. [Geosystems Institute, Moscow (Russian Federation)

    1997-10-01

    The GALO basin evolution model described in Makhous et al. is applied to evaluate hydrocarbon generation and migration histories in several Saharan basins. Three basins, the Oued el-Mya, Ghadames, and Illizi, are located in the central and eastern parts of the Saharan platform and are investigated in detail. The Ahnet, Mouydir, Timimoun, Reggane, and other basins located in the southern and western parts of the platform are also studied. The modeling results, combined with geochemical data, are used in a synthesis of the regional framework. The thermal gradients in the Ghadames and Illizi basins are greater than those in the Oued el-Mya basin. This difference is attributed to differences in sedimentation and subsidence rates, to less Hercynian erosion, and to fewer occurrences of evaporates in the Akfadou region of the Ghadames basin and in the Mereksen region of the Illizi basin. In the southern and western parts of the Illizi province, the major subsidence occurred before Hercynian uplift. Very moderate Hercynian uplift in the Ghadames and Illizi basins did not involve a significant decrease of temperatures, and organic matter maturation continued, but at slower rates. As a result, the realization of hydrocarbon potential appears to be higher than would be expected. Favorable traps are located near subsided areas where the source shales (particularly the Devonian) were not subjected to uplift and erosion. In this respect, the eastern Sahara including the Ghadames and Illizi basins is a favored province. Analysis of the distribution of present-day temperatures and paleotemperatures in the Paleozoic sediments of the Triassic province (Oued el-Mya, Ghadames, Trias, and north Illizi basins), combined with effective source rock occurrences, shows that favorable conditions for hydrocarbon generation during the Paleozoic occurred essentially in the southern and southwestern parts of the province.

  6. A model-based analysis of chemical and temporal patterns of cuticular hydrocarbons in male Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Clement Kent

    Full Text Available Drosophila Cuticular Hydrocarbons (CH influence courtship behaviour, mating, aggregation, oviposition, and resistance to desiccation. We measured levels of 24 different CH compounds of individual male D. melanogaster hourly under a variety of environmental (LD/DD conditions. Using a model-based analysis of CH variation, we developed an improved normalization method for CH data, and show that CH compounds have reproducible cyclic within-day temporal patterns of expression which differ between LD and DD conditions. Multivariate clustering of expression patterns identified 5 clusters of co-expressed compounds with common chemical characteristics. Turnover rate estimates suggest CH production may be a significant metabolic cost. Male cuticular hydrocarbon expression is a dynamic trait influenced by light and time of day; since abundant hydrocarbons affect male sexual behavior, males may present different pheromonal profiles at different times and under different conditions.

  7. Hybrid Grey Forecasting Model for Iran’s Energy Consumption and Supply

    Directory of Open Access Journals (Sweden)

    Hamidreza Mostafaei

    2012-07-01

    Full Text Available Grey theory deals with systems that are characterized by poor information or for which information is lacking. This study presents an improved grey GM (1, 1 model, using a technique that combines residual modification with Markov Chain model. We use energy consumption and supply of Iran to test the accuracy of proposed model. The results show that the Markov Chain residual modification model achieves reliable and precise results.

  8. DESIGNING A SUPPLY CHAIN MODEL WITH CONSIDERATION DEMAND FORECASTING AND INFORMATION SHARING

    Directory of Open Access Journals (Sweden)

    S.M.T. Fatemi Ghomi

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: In traditional supply chain inventory management, orders are the only information firms exchange, but information technology now allows firms to share demand and inventory data quickly and inexpensively. To have an integrated plan, a manufacturer not only needs to know demand information from its customers but also supply information from its suppliers. In this paper, information flow is incorporated in a three-echelon supply chain model. Also to decrease the risk of the supply chain system, the customers’ demands are predicted first and this prediction is then used as an input to the supply chain model. In this paper a proposed evolving fuzzy predictor model will be used to predict the customers’ demands. For solving the supply chain model, a hybrid heuristic combining tabu search with simulated annealing sharing the same tabu list is developed.

    AFRIKAANSE OPSOMMING: In tradisionele voorsieningskettingvoorraadbestuur verteenwoordig bestellings die enigste vorm van van inligting wat deur ondernemings uitgeruil word. Inligtingstegnologie laat ondernemings egter deesdae toe om vraag- en voorraadata vinnig en goedkoop uit te ruil. Om 'n geïntegreerde plan te hê, het 'n vervaardiger nie alleen aanvraaginligting nodig van sy klante nie, maar ook aanbodinligting van sy leweransiers. In hierdie artikel word inligtingvloei geinkorporeer in 'n drie-vlakvoorsieningskettingmodel. Voorts, om die risiko in die voorsieningskettingmodel te verminder, word die klante se aanvraag eers vooruitgeskat en die vooruitskatting word dan gebruik as 'n inset tot die model. Hierdie artikel gebruik 'n groeiende wasige vooruitskattingsmodel om die klantebehoeftes voor uit te skat. Om die model op te los, word 'n hibriede heuristiese metode gekombineer met 'n "tabu"-soektog gebruik.

  9. Model studies for evaluating the acute neurobehavioral effects of complex hydrocarbon solvents. I. Validation of methods with ethanol

    NARCIS (Netherlands)

    McKee, R.H.; Lammers, J.H.C.M.; Hoogendijk, E.M.G.; Emmen, H.H.; Muijser, H.; Barsotti, D.A.; Owen, D.E.; Kulig, B.M.

    2006-01-01

    As a preliminary step to evaluating the acute neurobehavioral effects of hydrocarbon solvents and to establish a working model for extrapolating animal test data to humans, joint neurobehavioral/toxicokinetic studies were conducted which involved administering ethanol to rats and volunteers. The spe

  10. Evaluation of Empirical Data and Modeling Studies to Support Soil Vapor Intrusion Screening Criteria for Petroleum Hydrocarbon Compounds

    Science.gov (United States)

    This study is an evaluation of empirical data and select modeling studies of the behavior of petroleum hydrocarbon (PHC) vapors in subsurface soils and how they can affect subsurface-to-indoor air vapor intrusion (VI), henceforth referred to as petroleum vapor intrusion or “PVI” ...

  11. Dynamic Model of the Universal Motor Supplied by a Harmonic Voltage Dynamic Model of the Universal Motor Supplied by a Harmonic Voltage

    Directory of Open Access Journals (Sweden)

    Jan Dupej

    2005-01-01

    Full Text Available In present article a dynamic model of universal motors, based on the measured data is developed. Suppose that the supply voltage is harmonic and motor operate in open circuit loop. After representing of the mathematical model a simulation model based on the Matlab-Simulink is derived; this allows for the determination of the waveforms of the speed current and torque of the machine for different state operation. Induced voltage of the rotor is determined as a function of the magnetic core saturation and of the armature reaction.In present article a dynamic model of universal motors, based on the measured data is developed. Suppose that the supply voltage is harmonic and motor operate in open circuit loop. After representing of the mathematical model a simulation model based on the Matlab-Simulink is derived; this allows for the determination of the waveforms of the speed current and torque of the machine for different state operation. Induced voltage of the rotor is determined as a function of the magnetic core saturation and of the armature reaction.

  12. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation

    Science.gov (United States)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  13. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation.

    Science.gov (United States)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  14. APPLYING A JUST-IN-TIME INTEGRATED SUPPLY CHAIN MODEL WITH INVENTORY AND WASTE REDUCTION CONSIDERATIONS

    Directory of Open Access Journals (Sweden)

    Li-Hsing Ho

    2013-01-01

    Full Text Available Just-In-Time (JIT has been playing an important role in supply chain environments. Countless firms have been applying JIT in production to gain and maintain a competitive advantage. This study introduces an innovative model which integrates inventory and quality assurance in a JIT supply chain. This approach assumes that manufacturing will produce some defective items and those products will not influence the buyer’s purchase policy. The vendor absorbs all the inspection costs. Using a function to compute the expected amount of total cost every year will minimize the total cost and the nonconforming fraction. Finally, a numerical example further confirms this model.

  15. Network design and operational modelling for construction green supply chain management

    Directory of Open Access Journals (Sweden)

    Pengfei Zhou Dong Chen

    2013-01-01

    Full Text Available Based on studying organizational structure of Construction Green Supply Chain Management (CGSCM, a mathematical programming model of CGSCM was proposed. The model aimed to maximize the aggregate profits of normalized construction logistics, the reverse logistics and the environmental performance. Numerical experiments show that the proposed approach can improve the aggregate profit effectively. In addition, return ratio, subsidies from governmental organizations, and environmental performance were analyzed for CGSCM performance. Herein, the proper return, subsidy and control strategy could optimize construction green supply chain.

  16. Modelling of a Serial Wound DC Motor Supplied by a Semi-Controlled Rectifier

    Directory of Open Access Journals (Sweden)

    Pavel Zaskalicky

    2006-01-01

    Full Text Available A serial wound DC motor is one of most used electrical machines in a small electrical instruments and home equipments by reason, that its speed is easily controlled by a supply voltage. Suppose that the motor is supplied by a semicontrolled rectifier and operate in open circuit loop. After representing of the mathematical model, a simulation model based on the Matlab-Simulink is derived; this allows for the determination of the waveforms of the speed current and torque of the machine for different state operation. Induced voltage of the rotor is determined as a function of the magnetic core saturation and of the armature reaction.

  17. Coopetitive Supply Chain Relationship Model: Application to the Smartphone Manufacturing Network.

    Science.gov (United States)

    Kwok, Jeremy Jie Ming; Lee, Dong-Yup

    2015-01-01

    Previous researches for understanding supply chain relationship have mostly focused on its vertical collaboration between buyers and suppliers. However, there have been some instances of volatile and stable collaborative relationships amongst competitors such as Apple-Samsung product manufacturer-component supplier relationship and airline alliances, respectively, which is recognized as coopetition. Even though there have been several qualitative studies and a number of game theory models on coopetition, it is rare to find any attempts on quantitative characterization of such coopetitive dynamic behavior in supply chain relationship. Hence, in this work, we formulated a MINLP model mathematically representing coopetitive relationships in a cost efficient supply chain network. In particular, the coopetition factor was newly introduced to measure the degree of coopetition among supply chain players and determine the optimal level of coopetition to engage in. The utility and practicality of the model were strongly demonstrated using a case study of a hypothetical smartphone supply chain network under different scenarios, thus proposing their strategically viable optimal interactions. Therefore, this exploratory study can herald a new era of global coopetitive business.

  18. Coopetitive Supply Chain Relationship Model: Application to the Smartphone Manufacturing Network.

    Directory of Open Access Journals (Sweden)

    Jeremy Jie Ming Kwok

    Full Text Available Previous researches for understanding supply chain relationship have mostly focused on its vertical collaboration between buyers and suppliers. However, there have been some instances of volatile and stable collaborative relationships amongst competitors such as Apple-Samsung product manufacturer-component supplier relationship and airline alliances, respectively, which is recognized as coopetition. Even though there have been several qualitative studies and a number of game theory models on coopetition, it is rare to find any attempts on quantitative characterization of such coopetitive dynamic behavior in supply chain relationship. Hence, in this work, we formulated a MINLP model mathematically representing coopetitive relationships in a cost efficient supply chain network. In particular, the coopetition factor was newly introduced to measure the degree of coopetition among supply chain players and determine the optimal level of coopetition to engage in. The utility and practicality of the model were strongly demonstrated using a case study of a hypothetical smartphone supply chain network under different scenarios, thus proposing their strategically viable optimal interactions. Therefore, this exploratory study can herald a new era of global coopetitive business.

  19. Performance metric optimization advocates CPFR in supply chains: A system dynamics model based study

    Directory of Open Access Journals (Sweden)

    Balaji Janamanchi

    2016-12-01

    Full Text Available Background: Supply Chain partners often find themselves in rather helpless positions, unable to improve their firm’s performance and profitability because their partners although willing to share production information do not fully collaborate in tackling customer order variations as they don’t seem to appreciate the benefits of such collaboration. Methods: We use a two-player (supplier-manufacturer System Dynamics model to study the dynamics to assess the impact and usefulness of supply chain partner collaboration on the supply chain performance measures. Results: Simulation results of supply chain metrics under varied customer order patterns viz., basecase, random normal, random uniform, random upwardtrend, and random downwardtrend under (a basecase, (b independent optimization by manufacturer, and (c collaborative optimization by manufacturer and supplier, are obtained to contrast them to develop useful insights. Conclusions: Focus on obtaining improved inventory turns with optimization techniques provides some viable options to managers and makes a strong case for increased collaborative planning forecasting and replenishment (CPFR in supply chains. Despite the differences in the inventory management practices that it was contrasted with, CPFR has proven to be beneficial in a supply chain environment for all SC partners.

  20. An Innovative Interactive Modeling Tool to Analyze Scenario-Based Physician Workforce Supply and Demand

    Science.gov (United States)

    Gupta, Saurabh; Black-Schaffer, W. Stephen; Crawford, James M.; Gross, David; Karcher, Donald S.; Kaufman, Jill; Knapman, Doug; Prystowsky, Michael B.; Wheeler, Thomas M.; Bean, Sarah; Kumar, Paramhans; Sharma, Raghav; Chamoli, Vaibhav; Ghai, Vikrant; Gogia, Vineet; Weintraub, Sally; Cohen, Michael B.

    2015-01-01

    Effective physician workforce management requires that the various organizations comprising the House of Medicine be able to assess their current and future workforce supply. This information has direct relevance to funding of graduate medical education. We describe a dynamic modeling tool that examines how individual factors and practice variables can be used to measure and forecast the supply and demand for existing and new physician services. The system we describe, while built to analyze the pathologist workforce, is sufficiently broad and robust for use in any medical specialty. Our design provides a computer-based software model populated with data from surveys and best estimates by specialty experts about current and new activities in the scope of practice. The model describes the steps needed and data required for analysis of supply and demand. Our modeling tool allows educators and policy makers, in addition to physician specialty organizations, to assess how various factors may affect demand (and supply) of current and emerging services. Examples of factors evaluated include types of professional services (3 categories with 16 subcategories), service locations, elements related to the Patient Protection and Affordable Care Act, new technologies, aging population, and changing roles in capitated, value-based, and team-based systems of care. The model also helps identify where physicians in a given specialty will likely need to assume new roles, develop new expertise, and become more efficient in practice to accommodate new value-based payment models. PMID:28725751

  1. An Innovative Interactive Modeling Tool to Analyze Scenario-Based Physician Workforce Supply and Demand

    Directory of Open Access Journals (Sweden)

    Saurabh Gupta BPharm

    2015-10-01

    Full Text Available Effective physician workforce management requires that the various organizations comprising the House of Medicine be able to assess their current and future workforce supply. This information has direct relevance to funding of graduate medical education. We describe a dynamic modeling tool that examines how individual factors and practice variables can be used to measure and forecast the supply and demand for existing and new physician services. The system we describe, while built to analyze the pathologist workforce, is sufficiently broad and robust for use in any medical specialty. Our design provides a computer-based software model populated with data from surveys and best estimates by specialty experts about current and new activities in the scope of practice. The model describes the steps needed and data required for analysis of supply and demand. Our modeling tool allows educators and policy makers, in addition to physician specialty organizations, to assess how various factors may affect demand (and supply of current and emerging services. Examples of factors evaluated include types of professional services (3 categories with 16 subcategories, service locations, elements related to the Patient Protection and Affordable Care Act, new technologies, aging population, and changing roles in capitated, value-based, and team-based systems of care. The model also helps identify where physicians in a given specialty will likely need to assume new roles, develop new expertise, and become more efficient in practice to accommodate new value-based payment models.

  2. EIA model documentation: Documentation of the Oil and Gas Supply Module (OGSM)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    The purpose of this report is to define the objectives of the Oil and Gas Supply Model (OGSM), to describe the model`s basic approach, and to provide detail on how the model works. This report is intended as a reference document for model analysts, users, and the public. Projected production estimates of US crude oil and natural gas are based on supply functions generated endogenously within National Energy Modeling System (NEMS) by the OGSM. OGSM encompasses domestic crude oil and natural gas supply by both conventional and nonconventional recovery techniques. Nonconventional recovery includes enhanced oil recovery (EOR), and unconventional gas recovery (UGR) from tight gas formations, Devonian shale and coalbeds. Crude oil and natural gas projects are further disaggregated by geographic region. OGSM projects US domestic oil and gas supply for six Lower 48 onshore regions, three offshore regions, and Alaska. The general methodology relies on forecasted drilling expenditures and average drilling costs to determine exploratory and developmental drilling levels for each region and fuel type. These projected drilling levels translate into reserve additions, as well as a modification of the production capacity for each region. OGSM also represents foreign trade in natural gas, imports and exports by entry region.

  3. Analisis Ramalan Persediaan Semen Model Economic Order Quantity (EOQ) Pada Toko Material Panglong Jaya Bangun Berbasis Supply Chain Management (SCM)

    OpenAIRE

    Putra, Mirza Gunawansyah

    2016-01-01

    Each company (Services/manufacturing) always needed supplies. Skilled in managing supplies is the result of coveted. Every entrepreneur where able to provide products in accordance with their customers need. One of the many businessman always needed supplies like the Store Building Panglong Jaya Bangun do needed to managed that supplies. The purpose of this research is to find out and analyze qualitatively Model Economic Order Quantity (EOQ) to forecasting that inventory of cement at The s...

  4. Parsing pyrogenic polycyclic aromatic hydrocarbons: forensic chemistry, receptor models, and source control policy.

    Science.gov (United States)

    O'Reilly, Kirk T; Pietari, Jaana; Boehm, Paul D

    2014-04-01

    A realistic understanding of contaminant sources is required to set appropriate control policy. Forensic chemical methods can be powerful tools in source characterization and identification, but they require a multiple-lines-of-evidence approach. Atmospheric receptor models, such as the US Environmental Protection Agency (USEPA)'s chemical mass balance (CMB), are increasingly being used to evaluate sources of pyrogenic polycyclic aromatic hydrocarbons (PAHs) in sediments. This paper describes the assumptions underlying receptor models and discusses challenges in complying with these assumptions in practice. Given the variability within, and the similarity among, pyrogenic PAH source types, model outputs are sensitive to specific inputs, and parsing among some source types may not be possible. Although still useful for identifying potential sources, the technical specialist applying these methods must describe both the results and their inherent uncertainties in a way that is understandable to nontechnical policy makers. The authors present an example case study concerning an investigation of a class of parking-lot sealers as a significant source of PAHs in urban sediment. Principal component analysis is used to evaluate published CMB model inputs and outputs. Targeted analyses of 2 areas where bans have been implemented are included. The results do not support the claim that parking-lot sealers are a significant source of PAHs in urban sediments. © 2013 SETAC.

  5. Degradation of polycyclic aromatic hydrocarbons : model simulation for bioavailability and biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Owabor, C.N.; Ogbeide, S.E. [Benin Univ. (Nigeria). Dept. of Chemical Engineering; Susu, A.A. [Lagos Univ. (Nigeria). Dept. of Chemical Engineering

    2010-04-15

    Research has indicated that the biodegradation of polycyclic aromatic hydrocarbons (PAHs) is influenced by the molecular size of the PAHs as well as by soil properties. This study presented a model for a 1-D convective-dispersive solute transport in a soil matrix. The model was designed to consider the gas-liquid interface film and the biofilm between the liquid and solid interface as well as to account for interparticle; intraparticle, and interphase mass transport. A soil microcosm reactor was used to evaluate substrate bioavailability and biodegradation in a contaminated aqueous solids system. The numerical model involved the discretization of depth, radial distance, and time into mesh or grid points with constant intervals. Dimensionless variables were defined using a backward finite difference (BFD) method. Results of the study suggested that PAH occlusion occurred in the micropores of the soil particle. The non-steady state model adequately predicted the concentration profiles of PAHs within the soil matrix. 26 refs., 5 tabs., 7 figs.

  6. Simulation and modeling of the hydrocarbon generation-migration-mixing processes in Louisiana`s sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.K.; Shi, Ying [Louisiana State Univ., Baton Rouge, LA (United States)

    1996-09-01

    Mixed-age Mesozoic and Cenozoic hydrocarbons are present in many Louisiana oil and gas reservoirs. This phenomenon has added fuel to the controversy over whether the hydrocarbon source rocks underwent {open_quotes}shallow{close_quotes} or {open_quotes}deep{close_quotes} burial. Source rock generating capacities and timing of maturation, expulsion, and migration are important factors in providing a potential solution to the problem. The purpose of this paper is to reconstruct the dynamic processes of oil and gas generation-migration-mixing in Louisiana basins by using numerical simulation. Problem solution employed a finite difference model which simulates numerically five processes on 2D vertical grids: (1) reconstruction of geological evolution as a result of sedimentation, erosion, and compaction; (2) computation of paleotemperatures based on constant crustal heat flow; (3) computation of source rock maturity based on a first-order kinetic model; (4) computation of geopressure based upon the result of compaction disequilibrium; and (5) computation of hydrocarbon expulsion and migration rates based on calculated results of maturity and geopressure reconstruction. This simulation/model yields plausible results for estimating potential regional reservoir volumetric distributions. The integrated approach used in this study provides a means for analyzing the dynamic processes of oil and gas generation-migration-mixing in Louisiana`s hydrocarbon systems. It also provides a basis for designing objective oil and gas trend analysis.

  7. Modelling supply and demand of bioenergy from short rotation coppice and Miscanthus in the UK.

    Science.gov (United States)

    Bauen, A W; Dunnett, A J; Richter, G M; Dailey, A G; Aylott, M; Casella, E; Taylor, G

    2010-11-01

    Biomass from lignocellulosic energy crops can contribute to primary energy supply in the short term in heat and electricity applications and in the longer term in transport fuel applications. This paper estimates the optimal feedstock allocation of herbaceous and woody lignocellulosic energy crops for England and Wales based on empirical productivity models. Yield maps for Miscanthus, willow and poplar, constrained by climatic, soil and land use factors, are used to estimate the potential resource. An energy crop supply-cost curve is estimated based on the resource distribution and associated production costs. The spatial resource model is then used to inform the supply of biomass to geographically distributed demand centres, with co-firing plants used as an illustration. Finally, the potential contribution of energy crops to UK primary energy and renewable energy targets is discussed. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. Applying Fuzzy Multiobjective Integrated Logistics Model to Green Supply Chain Problems

    Directory of Open Access Journals (Sweden)

    Chui-Yu Chiu

    2014-01-01

    Full Text Available The aim of this paper is attempting to explore the optimal way of supply chain management within the domain of environmental responsibility and concerns. The background of this research involves the issue of green supply chain management (GSCM and the concept of the multiobjective integrated logistics model. More specifically, in this paper, we suggest the fuzzy multiobjective integrated logistics model with the transportation cost and demand fuzziness to solve green supply chain problems in the uncertain environment which is illustrated via the detailed numerical example. Results and the sensitivity analysis of the numerical example indicate that when the governmental subsidy value increased the profits of the reverse chain also increased. The finding shows that the governmental subsidy policy could remain of significant influence for used-product reverse logistics chain.

  9. Multi-scale process and supply chain modelling: from lignocellulosic feedstock to process and products.

    Science.gov (United States)

    Hosseini, Seyed Ali; Shah, Nilay

    2011-04-06

    There is a large body of literature regarding the choice and optimization of different processes for converting feedstock to bioethanol and bio-commodities; moreover, there has been some reasonable technological development in bioconversion methods over the past decade. However, the eventual cost and other important metrics relating to sustainability of biofuel production will be determined not only by the performance of the conversion process, but also by the performance of the entire supply chain from feedstock production to consumption. Moreover, in order to ensure world-class biorefinery performance, both the network and the individual components must be designed appropriately, and allocation of resources over the resulting infrastructure must effectively be performed. The goal of this work is to describe the key challenges in bioenergy supply chain modelling and then to develop a framework and methodology to show how multi-scale modelling can pave the way to answer holistic supply chain questions, such as the prospects for second generation bioenergy crops.

  10. Development of the Integrated Biomass Supply Analysis and Logistics Model (IBSAL)

    Energy Technology Data Exchange (ETDEWEB)

    Sokhansanj, Shahabaddine [ORNL; Webb, Erin [ORNL; Turhollow Jr, Anthony F [ORNL

    2008-06-01

    The Integrated Biomass Supply & Logistics (IBSAL) model is a dynamic (time dependent) model of operations that involve collection, harvest, storage, preprocessing, and transportation of feedstock for use at a biorefinery. The model uses mathematical equations to represent individual unit operations. These unit operations can be assembled by the user to represent the working rate of equipment and queues to represent storage at facilities. The model calculates itemized costs, energy input, and carbon emissions. It estimates resource requirements and operational characteristics of the entire supply infrastructure. Weather plays an important role in biomass management and thus in IBSAL, dictating the moisture content of biomass and whether or not it can be harvested on a given day. The model calculates net biomass yield based on a soil conservation allowance (for crop residue) and dry matter losses during harvest and storage. This publication outlines the development of the model and provides examples of corn stover harvest and logistics.

  11. Identifying the optimal supply temperature in district heating networks - A modelling approach

    DEFF Research Database (Denmark)

    Mohammadi, Soma; Bojesen, Carsten

    2014-01-01

    of this study is to develop a model for thermo-hydraulic calculation of low temperature DH system. The modelling is performed with emphasis on transient heat transfer in pipe networks. The pseudo-dynamic approach is adopted to model the District Heating Network [DHN] behaviour which estimates the temperature...... dynamically while the flow and pressure are calculated on the basis of steady state conditions. The implicit finite element method is applied to simulate the transient temperature behaviour in the network. Pipe network heat losses, pressure drop in the network and return temperature to the plant...... are calculated in the developed model. The model will serve eventually as a basis to find out the optimal supply temperature in an existing DHN in later work. The modelling results are used as decision support for existing DHN; proposing possible modifications to operate at optimal supply temperature....

  12. e-Commerce and supply chains: Modelling of dynamics through fuzzy enhanced high level petri net

    Indian Academy of Sciences (India)

    Vipul Jain; S Wadhwa; S G Deshmukh

    2005-04-01

    Although information plays a major role in effective functioning of supply chain networks (SCNs), studies that deal specifically with the dynamics of supply chains are few. This problem is relatively new since fast communications and the means to employ it for effective management of supply chains did not exist till recently. In order to provide a vehicle for dynamic modelling and analysis of supply chain operations in vague and uncertain environments, we propose a fuzzy enhanced high level petri net (FEHLPN) model. The proposed model captures the capability of petri nets for graphical and analytical representation of dynamic SCNs with the management of uncertain information provided by fuzzy logic. The dynamics associated with two production planning and control policies are modelled, viz. make-to-stock and assemble-to-order in vague and ambiguous situations in electronic commerce environment. A fuzzy set and fuzzy truth-values are attached to an uncertain fuzzy token to model imprecision and uncertainty. The proposed FEHLPN incorporates essential aspects of rule-based systems, such as conservation of facts, refraction, and closed-world assumption.

  13. Optimization models of the supply of power structures’ organizational units with centralized procurement

    Directory of Open Access Journals (Sweden)

    Sysoiev Volodymyr

    2013-01-01

    Full Text Available Management of the state power structures’ organizational units for materiel and technical support requires the use of effective tools for supporting decisions, due to the complexity, interdependence, and dynamism of supply in the market economy. The corporate nature of power structures is of particular interest to centralized procurement management, as it provides significant advantages through coordination, eliminating duplication, and economy of scale. This article presents optimization models of the supply of state power structures’ organizational units with centralized procurement, for different levels of simulated materiel and technical support processes. The models allow us to find the most profitable options for state power structures’ organizational supply units in a centre-oriented logistics system in conditions of the changing needs, volume of allocated funds, and logistics costs that accompany the process of supply, by maximizing the provision level of organizational units with necessary material and technical resources for the entire planning period of supply by minimizing the total logistical costs, taking into account the diverse nature and the different priorities of organizational units and material and technical resources.

  14. Hybrid supply chain model for material requirement planning under financial constraints: A case study

    Science.gov (United States)

    Curci, Vita; Dassisti, Michele; Josefa, Mula Bru; Manuel, Díaz Madroñero

    2014-10-01

    Supply chain model (SCM) are potentially capable to integrate different aspects in supporting decision making for enterprise management tasks. The aim of the paper is to propose an hybrid mathematical programming model for optimization of production requirements resources planning. The preliminary model was conceived bottom-up from a real industrial case analysed oriented to maximize cash flow. Despite the intense computational effort required to converge to a solution, optimisation done brought good result in solving the objective function.

  15. Supply Chain Sustainability Analysis of Renewable Hydrocarbon Fuels via Indirect Liquefaction, Fast Pyrolysis, and Hydrothermal Liquefaction: Update of the 2016 State-of-Technology Cases and Design Cases

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Hao [Argonne National Lab. (ANL), Argonne, IL (United States; Dunn, Jennifer [Argonne National Lab. (ANL), Argonne, IL (United States; Pegallapati, Ambica [Argonne National Lab. (ANL), Argonne, IL (United States; Li, Qianfeng [Argonne National Lab. (ANL), Argonne, IL (United States; Canter, Christina [Argonne National Lab. (ANL), Argonne, IL (United States; Tan, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Biddy, Mary [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davis, Ryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Markham, Jennifer [National Renewable Energy Lab. (NREL), Golden, CO (United States); Talmadge, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hartley, Damon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Meyer, Pimphan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhu, Yunhua [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snowden-Swan, Lesley [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Susanne [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-02-01

    The Department of Energy’s (DOE) Bioenergy Technologies Office (BETO) aims to develop and deploy technologies to transform renewable biomass resources into commercially viable, high-performance biofuels, bioproducts and biopower through public and private partnerships (DOE, 2016). BETO and its national laboratory teams conduct in-depth technoeconomic assessments (TEA) of biomass feedstock supply and logistics and conversion technologies to produce biofuels, and life-cycle analysis of overall system sustainability.

  16. Multimedia model for polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs in Lake Michigan.

    Science.gov (United States)

    Huang, Lei; Batterman, Stuart A

    2014-12-02

    Polycyclic aromatic hydrocarbon (PAH) contamination in the U.S. Great Lakes has long been of concern, but information regarding the current sources, distribution, and fate of PAH contamination is lacking, and very little information exists for the potentially more toxic nitro-derivatives of PAHs (NPAHs). This study uses fugacity, food web, and Monte Carlo models to examine 16 PAHs and five NPAHs in Lake Michigan, and to derive PAH and NPAH emission estimates. Good agreement was found between predicted and measured PAH concentrations in air, but concentrations in water and sediment were generally under-predicted, possibly due to incorrect parameter estimates for degradation rates, discharges to water, or inputs from tributaries. The food web model matched measurements of heavier PAHs (≥5 rings) in lake trout, but lighter PAHs (≤4 rings) were overpredicted, possibly due to overestimates of metabolic half-lives or gut/gill absorption efficiencies. Derived PAH emission rates peaked in the 1950s, and rates now approach those in the mid-19th century. The derived emission rates far exceed those in the source inventories, suggesting the need to reconcile differences and reduce uncertainties. Although additional measurements and physiochemical data are needed to reduce uncertainties and for validation purposes, the models illustrate the behavior of PAHs and NPAHs in Lake Michigan, and they provide useful and potentially diagnostic estimates of emission rates.

  17. Teaching for Diversity: Models for Expanding the Supply of Minority Teachers. A Policy Issue Perspective.

    Science.gov (United States)

    Villegas, Ana Maria; And Others

    This collection is based on two studies of approaches to increasing the supply of minority teachers. The first was a documentation study of programs supported by the Ford Foundation Minority Education Demonstration Project designed to attract minority candidates, prepare them well, and present model programs. The second study described a range of…

  18. A carbohydrate supply and demand model of vegetative growth: response to temperature and light.

    Science.gov (United States)

    Gent, Martin P N; Seginer, Ido

    2012-07-01

    Photosynthesis is the limiting factor in crop growth models, but metabolism may also limit growth. We hypothesize that, over a wide range of temperature, growth is the minimum of the supply of carbohydrate from photosynthesis, and the demand of carbohydrate to synthesize new tissue. Biosynthetic demand limits growth at cool temperatures and increases exponentially with temperature. Photosynthesis limits growth at warm temperatures and decreases with temperature. Observations of tomato seedlings were used to calibrate a model based on this hypothesis. Model predictions were tested with published data for growth and carbohydrate content of sunflower and wheat. The model qualitatively fitted the response of growth of tomato and sunflower to both cool and warm temperatures. The transition between demand and supply limitation occurred at warmer temperatures under higher light and faster photosynthesis. Modifications were required to predict the observed non-structural carbohydrate (NSC). Some NSC was observed at warm temperatures, where demand should exceed supply. It was defined as a required reserve. Less NSC was found at cool temperatures than predicted from the difference between supply and demand. This was explained for tomato and sunflower, by feedback inhibition of NSC on photosynthesis. This inhibition was much less in winter wheat.

  19. Business Process Modelling in Demand-Driven Agri-Food Supply Chains

    NARCIS (Netherlands)

    Verdouw, C.N.; Beulens, A.J.M.; Trienekens, J.H.; Wolfert, J.

    2010-01-01

    Agri-food companies increasingly participate in demand-driven supply chains that are able to adapt flexibly to changes in the marketplace. The objective of this presentation is to discuss a process modelling framework, which enhances the interoperability and agility of information systems as require

  20. Labor supply and retirement policy in an overlapping generations model with stochastic fertility

    DEFF Research Database (Denmark)

    Hagen Jørgensen, Ole; Hougaard Jensen, Svend E.

    Using a stochastic general equilibrium model with overlapping generations, this paper studies a policy rule for the retirement age aiming at offsetting the effects on the supply of labor following fertility changes. The authors find that the retirement age should increase more than proportionally...

  1. Adult Participation in Children's Word Searches: On the Use of Prompting, Hinting, and Supplying a Model

    Science.gov (United States)

    Radford, Julie

    2010-01-01

    Although word searching in children is very common, very little is known about how adults support children in the turns following the child's search behaviours, an important topic because of the social, educational, and clinical implications. This study characterizes, in detail, teachers' use of prompting, hinting, and supplying a model. From a…

  2. GEMFLOW: A time dependent model to assess responses to natural gas supply crises

    Energy Technology Data Exchange (ETDEWEB)

    Szikszai, A., E-mail: andras.szikszai@ec.europa.eu [European Commission, JRC-Institute for Energy, Energy Security Unit, P.O. Box 2, 1755 ZG Petten (Netherlands); Monforti, F. [European Commission, JRC-Institute for Energy, Energy Security Unit, P.O. Box 2, 1755 ZG Petten (Netherlands)

    2011-09-15

    The January 2009 gas dispute, followed by the biggest gas supply crisis ever, called for significant changes at the community level. In line with other measures (e.g. a new regulation to ensure security of gas supply), a new tool is needed that will help decision-makers react properly in such a situation. Based on Monte-Carlo modeling principles, this new tool is being developed to take the first step towards a comprehensive model. This model could be of great support to common European efforts in order to assess the possible outcomes of a supply disruption beforehand and minimize losses during an emergency by finding the optimal distribution of flows. Naturally, the described model cannot serve at present as hydraulic software that is currently used by the national system operators, but it is able to draw significant conclusions from the European gas system's capabilities. - Highlights: > Use of storages at maximum in case of supply shortfall is not necessarily the best solution. > The ratio of withdrawal capacity to storage space is crucial in the withdrawal utilization. > Combination of reverse flows and storages affects the success of disruption management. > Definition of lowest consumption level is inevitable for appropriate disruption management.

  3. Generalized Simulation Model for a Switched-Mode Power Supply Design Course Using MATLAB/SIMULINK

    Science.gov (United States)

    Liao, Wei-Hsin; Wang, Shun-Chung; Liu, Yi-Hua

    2012-01-01

    Switched-mode power supplies (SMPS) are becoming an essential part of many electronic systems as the industry drives toward miniaturization and energy efficiency. However, practical SMPS design courses are seldom offered. In this paper, a generalized MATLAB/SIMULINK modeling technique is first presented. A proposed practical SMPS design course at…

  4. Improved Weighted Shapley Value Model for the Fourth Party Logistics Supply Chain Coalition

    Directory of Open Access Journals (Sweden)

    Na Xu

    2013-01-01

    Full Text Available How to make the individual get the reasonable and practical profit among the fourth party logistics supply chain coalition system is still a question for further study. Considering the characteristics of the fourth party logistics supply chain coalition, this paper combines Shapley Value with Distribution according to Contribution, two methods in the application, and then adjusts the profit allocated to each member reasonably based on the actual coalition situation named improved weighted Shapley Value model. In this paper, we first analyze the fourth party logistics supply chain coalition profit allocation models, the classical Shapley value method. Then, we analyze the weight of individual enterprise in the coalition by the analytic hierarchy process. To each enterprise, the weight is determined by the investment risks, information divulging risks, and failure risks. Finally, the numerical study shows that the profit allocation method improved weighted Shapley value model is relatively rational and practical. Thus, the proposed combined model is a useful profit allocation mechanism for the fourth party logistics supply chain coalition that the contribution and risks are fully considered.

  5. OVERVIEW OF INFORMATION TECHNOLOGY AND A THEORETICAL MODEL IN SUPPLY CHAIN MANAGEMENT FOR LOCAL SMES

    Directory of Open Access Journals (Sweden)

    Kherbach OUALID

    2016-12-01

    Full Text Available Most literature on supply chain management (SCM focuses on large organizations with global operations employing high-level information technology. This creates a gap in the knowledge of how SMEs use and practice (SCM moreover (SCM is an area of increasing importance among enterprises and of growing academic interest. It is based on the concept of firms as part of multiple organizations oriented to the provision of goods and services for the final customer. the survival of Small to Medium Size Enterprises (SMEs will be determined by their ability to produce more, at a lower cost, in less time, and with few defects. The use of information technology (IT is considered a prerequisite for the effective control of today’s complex supply chains. In our research report we first provide a broad over of (SCM in general for SMEs. We further discuss the evolution of the information technology (IT in SCM and the performance parameters of the supply chain processes. In this research, the aim is to introduce a special (SCMtheoretical model in general SCM models which is appropriate for SMEs’ structure due to their operation capacity, numerical condition and other features. In accordance with this aim, taking the conditions of this sector into consideration, a two-stage model which is appropriate for structure of SMEs in Romania is proposed. The first stage of the model consists of “supply and production centers” and second stage consists of “product and customer center”

  6. A Modeling Tool for Evaluating Climate Change Impacts on Water Supply System

    Science.gov (United States)

    Chuang, L.; Tung, C.; Liu, T.

    2009-12-01

    Climate change may exacerbate short-term climate variability and more extreme hydrological events, and then may impact on human society and natural environment. Socioeconomic development is dependent on adequate water resources, but climate change may impact on such supply system, including available streamflow, groundwater, irrigation water demand. The purpose of this study is to apply an integrated modeling tool to assess the climate change impacts on regional water supply systems and then to propose response strategies to strengthen adaptive capacity to achieve sustainable water uses. The modeling tool integrates the functions of downscaling, weather generation, hydrological modeling, and an interface for linking system dynamics models. The Touchien river basin in Taiwan is chosen as a study area, which has a high-tech industry park. The vulnerability of the water supply system was evaluated for present and future conditions. The results demonstrated that the water supply system could meet current water demand, but might be subjected to serious water shortage due to future climate change and increasing water demand. At last, this study provides suggestions to government agency to develop better water resources management strategies to mitigate the impacts of changing climate.

  7. Addressing stakeholder conflicts in rural South Africa using a water supply model

    NARCIS (Netherlands)

    D' Hont, F.M.; Clifford-Holmes, J.K.; Slinger, J.H.

    2013-01-01

    A system dynamics modelling approach is adopted to deepen understanding of the effects of operational management on the performance of the Greater Kirkwood water supply system in South Africa. Currently, the interrupted operation of the system has led to perceptions of systemic social injustice on t

  8. OVERVIEW OF INFORMATION TECHNOLOGY AND A THEORETICAL MODEL IN SUPPLY CHAIN MANAGEMENT FOR LOCAL SMES

    Directory of Open Access Journals (Sweden)

    Kherbach OUALID

    2016-12-01

    Full Text Available Most literature on supply chain management (SCM focuses on large organizations with global operations employing high-level information technology. This creates a gap in the knowledge of how SMEs use and practice (SCM moreover (SCM is an area of increasing importance among enterprises and of growing academic interest. It is based on the concept of firms as part of multiple organizations oriented to the provision of goods and services for the final customer. the survival of Small to Medium Size Enterprises (SMEs will be determined by their ability to produce more, at a lower cost, in less time, and with few defects. The use of information technology (IT is considered a prerequisite for the effective control of today’s complex supply chains. In our research report we first provide a broad over of (SCM in general for SMEs. We further discuss the evolution of the information technology (IT in SCM and the performance parameters of the supply chain processes. In this research, the aim is to introduce a special (SCMtheoretical model in general SCM models which is appropriate for SMEs’ structure due to their operation capacity, numerical condition and other features. In accordance with this aim, taking the conditions of this sector into consideration, a two-stage model which is appropriate for structure of SMEs in Romania is proposed. The first stage of the model consists of “supply and production centers” and second stage consists of “product and customer center”

  9. Generalized Simulation Model for a Switched-Mode Power Supply Design Course Using MATLAB/SIMULINK

    Science.gov (United States)

    Liao, Wei-Hsin; Wang, Shun-Chung; Liu, Yi-Hua

    2012-01-01

    Switched-mode power supplies (SMPS) are becoming an essential part of many electronic systems as the industry drives toward miniaturization and energy efficiency. However, practical SMPS design courses are seldom offered. In this paper, a generalized MATLAB/SIMULINK modeling technique is first presented. A proposed practical SMPS design course at…

  10. A genetic algorithm approach for solving a closed loop supply chain model

    DEFF Research Database (Denmark)

    Kannan, G.; Sasikumar, P.; Kannan, Devika

    2010-01-01

    . Because of the need for environmental protection and the lack of considerable lead resources, the spent batteries treatment and lead recovery are becoming crucial now-a-days. The objective of this paper is to develop a multi echelon, multi period, multi product closed loop supply chain network model...

  11. Use of multilevel modeling for determining optimal parameters of heat supply systems

    Science.gov (United States)

    Stennikov, V. A.; Barakhtenko, E. A.; Sokolov, D. V.

    2017-07-01

    The problem of finding optimal parameters of a heat-supply system (HSS) is in ensuring the required throughput capacity of a heat network by determining pipeline diameters and characteristics and location of pumping stations. Effective methods for solving this problem, i.e., the method of stepwise optimization based on the concept of dynamic programming and the method of multicircuit optimization, were proposed in the context of the hydraulic circuit theory developed at Melentiev Energy Systems Institute (Siberian Branch, Russian Academy of Sciences). These methods enable us to determine optimal parameters of various types of piping systems due to flexible adaptability of the calculation procedure to intricate nonlinear mathematical models describing features of used equipment items and methods of their construction and operation. The new and most significant results achieved in developing methodological support and software for finding optimal parameters of complex heat supply systems are presented: a new procedure for solving the problem based on multilevel decomposition of a heat network model that makes it possible to proceed from the initial problem to a set of interrelated, less cumbersome subproblems with reduced dimensionality; a new algorithm implementing the method of multicircuit optimization and focused on the calculation of a hierarchical model of a heat supply system; the SOSNA software system for determining optimum parameters of intricate heat-supply systems and implementing the developed methodological foundation. The proposed procedure and algorithm enable us to solve engineering problems of finding the optimal parameters of multicircuit heat supply systems having large (real) dimensionality, and are applied in solving urgent problems related to the optimal development and reconstruction of these systems. The developed methodological foundation and software can be used for designing heat supply systems in the Central and the Admiralty regions in

  12. 风险环境中基于Supply-Hub的建筑工程供应链协同模型优化%Optimization of Construction Project Supply Chain Collaboration Model in Risky Environment Based on Supply-hub

    Institute of Scientific and Technical Information of China (English)

    卫飚; 李毅鹏

    2014-01-01

    In this paper, we proposed the collaboration model of a construction project supply chain based on supply-hub, then adopted the Monte Carlo simulation process to simulate the whole process of the supply chain, and found that, as compared to the traditional non-collaborative models, the supply-hub based collaborative model could remarkably reduce the supply chain cost and improve the total profit and performance of the supply chain.%考虑由多个建筑材料供应商、单个总承包商和业主所组成的建筑工程供应链。在供应商的材料供应和业主的需求都存在不确定性的环境中,总承包商采取了三种不同的应对风险的态度偏好:风险中性、延误规避和浪费规避。提出了基于Supply-Hub的建筑工程供应链协同模型,并采用Monte Carlo仿真模拟供应链的运作全过程。数据结果显示:采用了Supply-Hub的协同模型相比于传统的非协同模型,有效地减低了供应链的成本、提高了供应链的总利润和绩效、整个建筑工程供应链达到了帕累托改善。

  13. H∞ Control of Supply Chain Based on Switched Model of Stock Level

    Directory of Open Access Journals (Sweden)

    Junzhi Luo

    2014-01-01

    Full Text Available This paper is concerned with the problem of H∞ control for a class of discrete supply chain systems. A new method based on network control technique is presented to address this issue. Supply chain systems are modeled as networked systems with stochastic time delay. Sufficient conditions for H∞ controller design are given in terms of a set of linear matrix inequalities, based on which the mean-square asymptotic stability as well as H∞ performance is satisfied for such systems. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  14. Differential Dynamic Evolutionary Model of Emergency Financial Service Supply Chain in Natural Disaster Risk Management

    Directory of Open Access Journals (Sweden)

    Shujian Ma

    2016-01-01

    Full Text Available A government-market-public partnership (GMPP could be a feasible arrangement for providing insurance coverage for natural disaster. Firstly, we put forward GMPP management mode. Secondly, the emergency financial service supply chain for natural disaster risk is built from the view of supply chain. Finally, the objective of this paper is to obtain insights into the cooperative and competitive relationship in GMPP system. We establish the cooperative and competitive differential dynamic evolutionary models and prove the existence of equilibrium solutions in order to solve the coordination problems. In conclusion, the equilibrium solutions can be achieved among the insurers, the operating governments, and the public.

  15. Proposal for a Model of Co-Management for the Small Community Water Supplies in Colombia

    Directory of Open Access Journals (Sweden)

    Andrea Bernal

    2014-01-01

    Full Text Available This paper reviews the conceptual evolution of Community Based Monitoring (CBM from different approaches : social capital, common pool resources and co-management or collaborative management, and presents the main co-management strategies applied to water supply at small scale: local and community driven development (LCDD and sustainable services at scale (SSS. Supported by this theoretical background, and in order to improve access to drinking water in rural communities in Colombia, the authors propose a co-management model for small and community water supplies.

  16. The Life Cycle Evaluation Model of External Diseconomy of Open-loop Supply Chain

    Science.gov (United States)

    Liu, Qian; Hu, Tianjun

    2017-08-01

    In recent years, with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased, people began to use the method of recycling on waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method, comparative analysis through the case. This paper also concludes that the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.

  17. Physicians' perception of demand-induced supply in the information age: a latent class model analysis.

    Science.gov (United States)

    Shih, Ya-Chen Tina; Tai-Seale, Ming

    2012-03-01

    This paper introduces a concept called 'demand-induced supply' that reflects the excess supply of services due to an increase in demand initiated by patients. We examine its association with the proportion of information-savvy patients in physicians' practice. Using data from a national representative physician survey, we apply latent class models to analyze this association. Our analyses categorize physicians into three 'types' according to the frequency with which they provided additional medical services at their patients' requests: frequent, occasional, and rare. The proportion of information-savvy patients is significantly and positively correlated with demand-induced supply for the frequent or occasional type, but not among physicians in the rare type. Efforts to contain healthcare costs through utilization control need to recognize the pattern of responses from physicians who treat an increasing number of information-savvy patients. Copyright © 2011 John Wiley & Sons, Ltd.

  18. Supply-demand 3D dynamic model in water resources evaluation: taking Lebanon as an example

    Science.gov (United States)

    Fang, Hong; Hou, Zhimin

    2017-05-01

    In this paper, supply-demand 3D dynamic model is adopted to create a measurement of a region’s capacity to provide available water to meet the needs of its population. First of all, we draw a diagram between supply and demand. Then taking the main dynamic factors into account, we establish an index to evaluate the balance of supply and demand. The three dimension vector reflects the scarcity of industrial, agricultural and residential water. Lebanon is chosen as the object of case study, and we do quantitative analysis of its current situation. After data collecting and processing, we calculate the 3D vector in 2012, which reveals that agriculture is susceptible to water scarcity. Water resources of Lebanon are “physical rich” but “economic scarcity” according to the correlation chart and other statistical analysis.

  19. Transport and supply logistics of biomass fuels: Vol. 2. Biomass and strategic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Allen, J.; Browne, M.; Cook, A.; Wicks, N.; Palmer, H.; Hunter, A.; Boyd, J.

    1996-10-01

    This document forms part of the United Kingdom Department of Trade and Industry project ''Transport and Logistics of Biomass Fuels'', which aimed to describe the distribution of existing and potential biomass resources in terms of their supply potential for power stations. Fixed areas of supply, or catchments, have been identified on colour maps of Britain showing the distribution of forest fuel, short rotation coppices, and various types of straw and animal slurry, using a specially written strategic modelling program. Adequate supplies of biomass resources are shown to exist in Britain, but siting of power stations to exploit these resources, will depend on transport and economic considerations appropriate at the time of construction. Biomass power stations in the megawatt capacity range could be resourced. (UK)

  20. A multi-objective reliable programming model for disruption in supply chain

    Directory of Open Access Journals (Sweden)

    Emran Mohammadi

    2013-05-01

    Full Text Available One of the primary concerns on supply chain management is to handle risk components, properly. There are various reasons for having risk in supply chain such as natural disasters, unexpected incidents, etc. When a series of facilities are built and deployed, one or a number of them could probably fail at any time due to bad weather conditions, labor strikes, economic crises, sabotage or terrorist attacks and changes in ownership of the system. The objective of risk management is to reduce the effects of different domains to an acceptable level. To overcome the risk, we propose a reliable capacitated supply chain network design (RSCND model by considering random disruptions risk in both distribution centers and suppliers. The proposed study of this paper considers three objective functions and the implementation is verified using some instance.

  1. Developing a Taxonomy and Model to Transfer and Assess Best Practices for Supply Chain Management

    Science.gov (United States)

    Flores, Myrna; Mendoza, Ana; Lavin, Victor; Flores, Benito

    Supply Chain Management can be briefly defined as the orchestration of a network of entities such as suppliers, distributors and clients to achieve a common goal: delivering cost efficient products and services exceeding customers’ expectations. Therefore, firms should consider all those End-to-End processes enabling an efficient integration and interoperability of partners collaborating in such Supply Chain when designing their Business Process Architecture (BPA). One key enabler to accomplish this goal is the identification, documentation and sharing of best practices. This paper describes the outcomes of a collaborative project carried out by CEMEX Research Group and the Universidad de Monterrey (UDEM), which focused on developing taxonomy to document best practices for the supply chain management together with a generic model to evaluate their level of implementation.

  2. Lean production in improving supply chain performance through hybrid model SCOR 11.0 - system dynamics

    Science.gov (United States)

    Saleh, Chairul; Fatcha Mubiena, Ghaida; Immawan, Taufiq; Hassan, Azmi

    2016-02-01

    Supply Chain Operation Reference (SCOR) is a method to measure supply chain serving the business process framework, performance indicators and unique technologies to support communication and collaboration among supply chain partners. The objective of this paper is to measure Supply Chain Management performance by using SCOR version 11.0 for production typology of MTS-MTO in Indonesian Batik Industry. This research combines SCOR's model and System Dynamics in order to predict the complex activities on batik industry. The hybrid SCOR-SD could identify the interaction among five attributes with the associated variables simultaneously. The results are obtained after the performance of lean production application is increased and the targets are achieved, even exceeding the target. For reliability attributes that associated with perfect order fulfilment started from 2015 to 2019 respectively are calculated as 80.06%, 103.53%, 105.58%, 93.76%, and 72.17%. Responsiveness attributes associated with the order fulfilment cycle time, respectively 122.45%, 149.10%, 159.26%, 131.53%, and 119.36%. Attributes associated with the total cost of service charge respectively 93.46%, 93.53%, 93.45%, 93.49, and 93.49%. Attributes associated with cash management assets to cash cycle time in a row were 160%, 153%, 146.3%, 150%, and 126.7%. The latter attribute is agility attributes associated with supply chain flexibility upside respectively 100%, 87.2%, 100%, 82%, and 82%.

  3. Research on TPL Service Level and Pricing Models in Supply Chain Coordination and Benefits Allocation

    Directory of Open Access Journals (Sweden)

    Ju Chunhua

    2013-05-01

    Full Text Available Research on the method to strengthen the cooperation among members to achieve win-win result is an important subject in SCM. Nevertheless, most studies to date on supply chain pricing have only assumed that the market demand is only influenced by retail price but not by logistics service level. That is why our work is concerned with logistics service and product pricing strategies in supply chain consisting of the manufacturer, the retailer and the TPL provider. For three-echelon supply chain system with TPL service level, use game theory to analyze its pricing, production, service levels and profit allocation. Three different models are discussed which are based on Stackelberg games and cooperative game. We find that the whole supply chain profit brought by collaborative decision-making is much higher than it independent decision-making brings based on the research. And it can increase the whole profit through reasonable setting of allocation proportion of profit. The study proposes multiple effective distribution methods of supply chain profit and takes an example to perform empirical analysis on the results to proof effectiveness.

  4. Transportation and dynamic networks: Models, theory, and applications to supply chains, electric power, and financial networks

    Science.gov (United States)

    Liu, Zugang

    Network systems, including transportation and logistic systems, electric power generation and distribution networks as well as financial networks, provide the critical infrastructure for the functioning of our societies and economies. The understanding of the dynamic behavior of such systems is also crucial to national security and prosperity. The identification of new connections between distinct network systems is the inspiration for the research in this dissertation. In particular, I answer two questions raised by Beckmann, McGuire, and Winsten (1956) and Copeland (1952) over half a century ago, which are, respectively, how are electric power flows related to transportation flows and does money flow like water or electricity? In addition, in this dissertation, I achieve the following: (1) I establish the relationships between transportation networks and three other classes of complex network systems: supply chain networks, electric power generation and transmission networks, and financial networks with intermediation. The establishment of such connections provides novel theoretical insights as well as new pricing mechanisms, and efficient computational methods. (2) I develop new modeling frameworks based on evolutionary variational inequality theory that capture the dynamics of such network systems in terms of the time-varying flows and incurred costs, prices, and, where applicable, profits. This dissertation studies the dynamics of such network systems by addressing both internal competition and/or cooperation, and external changes, such as varying costs and demands. (3) I focus, in depth, on electric power supply chains. By exploiting the relationships between transportation networks and electric power supply chains, I develop a large-scale network model that integrates electric power supply chains and fuel supply markets. The model captures both the economic transactions as well as the physical transmission constraints. The model is then applied to the New

  5. Global atmospheric emissions and transport of polycyclic aromatic hydrocarbons: Evaluation of modeling and transboundary pollution

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2014-05-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimated country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). MOZART-4 (The Model for Ozone and Related Chemical Tracers, version 4) was applied to simulate the global tropospheric transport of Benzo(a)pyrene, one of the high molecular weight carcinogenic PAHs, at a horizontal resolution of 1.875° (longitude) × 1.8947° (latitude). The reaction with OH radical, gas/particle partitioning, wet deposition, dry deposition, and dynamic soil/ocean-air exchange of PAHs were considered. The simulation was validated by observations at both background and non-background sites, including Alert site in Canadian High Arctic, EMEP sites in Europe, and other 254 urban/rural sites reported from literatures. Key factors effecting long-range transport of BaP were addressed, and transboundary pollution was discussed.

  6. The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point

    CERN Document Server

    Jones, A P; Koehler, M; Verstraete, L; Guillet, V; Bocchio, M; Ysard, N

    2014-01-01

    Context. The evolution of amorphous hydrocarbon materials, a-C(:H), principally resulting from ultraviolet (UV) photon absorption- induced processing, are likely at the heart of the variations in the observed properties of dust in the interstellar medium. Aims. The consequences of the size-dependent and compositional variations in a-C(:H), from aliphatic-rich a-C:H to aromatic-rich a-C, are studied within the context of the interstellar dust extinction and emission. Methods. Newly-derived optical property data for a-C(:H) materials, combined with that for an amorphous forsterite-type silicate with iron nano-particle inclusions, a-SilFe, are used to explore dust evolution in the interstellar medium. Results. We present a new dust model that consists of a power-law distribution of small a-C grains and log-normal distributions of large a-SilFe and a-C(:H) grains. The model, which is firmly anchored by laboratory-data, is shown to quite naturally explain the variations in the infrared (IR) to far-ultraviolet (FUV...

  7. Hydrocarbon fluxes above a Scots pine forest canopy: measurements and modeling

    Directory of Open Access Journals (Sweden)

    J. Rinne

    2007-06-01

    Full Text Available We measured the fluxes of several hydrocarbon species above a Scots pine (Pinus sylvestris stand using disjunct eddy covariance technique with proton transfer reaction – mass spectrometry. The measurements were conducted during four days in July at SMEAR II research station in Hyytiälä, Finland. Compounds which showed significant emission fluxes were methanol, acetaldehyde, acetone, and monoterpenes. A stochastic Lagrangian transport model with simple chemical degradation was applied to assess the sensitivity of the above canopy fluxes to chemistry. According to the model, the chemical degradation had a minor effect on the fluxes measured in this study but may have a major effect on the vertical flux profiles of more reactive compounds, such as sesquiterpenes. The monoterpene fluxes derived using M81 and M137 had a systematic difference with the latter one being higher. These fluxes followed the traditional exponential temperature dependent emission algorithm but were considerably higher than the fluxes measured before at the same site. The normalized monoterpene emission potentials at 30°C, obtained using the temperature dependence coefficient of 0.09°C−1, were 2.0 μg gdw−1 h−1 and 2.5 μg gdw−1 h−1, for fluxes derived using M81 and M137.

  8. Secondary production of toxic nitropolycyclic aromatic hydrocarbon during the Asian dust event: approached by model simulation

    Science.gov (United States)

    Inomata, Y.; Kajino, M.; Sato, K.

    2016-12-01

    Nitrated polycyclic aromatic hydrocarbons (NPAHs) are one of toxic compounds in the atmospheric particles. NPAHs are emitted in the atmosphere through the combustion of fossil fuels such as coal and diesel. Furthermore, it is produced by heterogeneous reactions such as the surface on the mineral dust aerosols. 1-nitoropyrene (1-NP) is one of the most abundant NPAHs and considered as a probable carcinogen. It is found that the production of 1-NP occurred during the heavy Asian dust event in Beijing and Japan. In this study, we estimated production of 1-NP by heterogeneous reactions by using model simulations in Northeast Asia. The model was three dimensional chemical transport model, Regional Air Quality Model for POPs version. The model performance was investigated the comparison with the observations. We focused on heavy Asian dust event observed in Beijing on 18-20 March 2010. Several sensitivity calculations are conducted under the existence of Asian dust in order to investigate the effect of relative humidity and photolysis. On 18-20 March 2010, primary 1-NP concentrations are about 50 fg/m3. Under the existence of the Asian dust, secondary production of 1-NP is estimated to 7 times against the concentrations of primary emission. Horizontal distributions indicate that decrease of Pyr and increase of 1-NP is significant around Beijing in this Asian dust event. Secondary production of 1-NP was large in this area as well as the downwind region such as the East China Sea. It is found that secondary production of 1-NP is minor in dessert region because of lower concentrations of Pyrene (Pyr). Distribution of secondary produced 1-NP varied with concentrations of Pyr, transport of Asian dust. Secondary production of 1-NP in March 2010 was larger than the primary emission of 1-NP, whereas the secondary production was smaller than those of the primary emission in April and May, 2011.

  9. Process modelling in demand-driven supply chains: A reference model for the fruit industry

    NARCIS (Netherlands)

    Verdouw, C.N.; Beulens, A.J.M.; Trienekens, J.H.; Wolfert, J.

    2010-01-01

    The growing importance of health in consumption is expected to result in a significant increase of European fruit demand. However, the current fruit supply does not yet sufficiently meet demand requirements. This urges fruit supply chains to become more demand-driven, that is, able to continuously m

  10. Sustainable supply chain management through enterprise resource planning (ERP): a model of sustainable computing

    OpenAIRE

    Broto Rauth Bhardwaj

    2015-01-01

    Green supply chain management (GSCM) is a driver of sustainable strategy. This topic is becoming increasingly important for both academia and industry. With the increasing demand for reducing carbon foot prints, there is a need to study the drivers of sustainable development. There is also need for developing the sustainability model. Using resource based theory (RBT) the present model for sustainable strategy has been developed. On the basis of data collected, the key drivers of sustainabili...

  11. Coordination buyer-supplier in supply chain models from net present value perspective

    OpenAIRE

    Hamontree, Chaowalit

    2014-01-01

    This thesis examines four parts of production and inventory models for buyer-supplier in the supply chain under deterministic conditions. The main objective is to find optimal lot-sizing decisions and inventory policies which derive from the classical inventory and Net Present Value (NPV) framework. Firstly, we study the production and inventory models from the classical framework to identify how to value the holding cost for buyer and supplier in the average profit or cost functions. Secondl...

  12. Monetary Policy Trade-Offs in a Portfolio Model with Endogenous Asset Supply

    OpenAIRE

    Schüder, Stefan

    2012-01-01

    This paper develops an open economy portfolio balance model with endogenous asset supply. Domestic producers choose an optimal capital structure and finance capital goods through credit, bonds and equity assets. Private households hold a portfolio of domestic and foreign assets, shift balances depending on risk-return considerations, and maximise real consumption in accordance with the law of one price. Within this general equilibrium model, it will be shown that central bank interventions ma...

  13. MODEL BASED BIOMASS SYSTEM DESIGN OF FEEDSTOCK SUPPLY SYSTEMS FOR BIOENERGY PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    David J. Muth, Jr.; Jacob J. Jacobson; Kenneth M. Bryden

    2013-08-01

    Engineering feedstock supply systems that deliver affordable, high-quality biomass remains a challenge for the emerging bioenergy industry. Cellulosic biomass is geographically distributed and has diverse physical and chemical properties. Because of this feedstock supply systems that deliver cellulosic biomass resources to biorefineries require integration of a broad set of engineered unit operations. These unit operations include harvest and collection, storage, preprocessing, and transportation processes. Design decisions for each feedstock supply system unit operation impact the engineering design and performance of the other system elements. These interdependencies are further complicated by spatial and temporal variances such as climate conditions and biomass characteristics. This paper develops an integrated model that couples a SQL-based data management engine and systems dynamics models to design and evaluate biomass feedstock supply systems. The integrated model, called the Biomass Logistics Model (BLM), includes a suite of databases that provide 1) engineering performance data for hundreds of equipment systems, 2) spatially explicit labor cost datasets, and 3) local tax and regulation data. The BLM analytic engine is built in the systems dynamics software package PowersimTM. The BLM is designed to work with thermochemical and biochemical based biofuel conversion platforms and accommodates a range of cellulosic biomass types (i.e., herbaceous residues, short- rotation woody and herbaceous energy crops, woody residues, algae, etc.). The BLM simulates the flow of biomass through the entire supply chain, tracking changes in feedstock characteristics (i.e., moisture content, dry matter, ash content, and dry bulk density) as influenced by the various operations in the supply chain. By accounting for all of the equipment that comes into contact with biomass from the point of harvest to the throat of the conversion facility and the change in characteristics, the

  14. Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic liquids and QSPR model

    Institute of Scientific and Technical Information of China (English)

    ZHU Jiqin; YU Yanmei; CHEN Jian; FEI Weiyang

    2007-01-01

    The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficients γ∞ at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement of γ∞ by gas-liquid chromatography is a speedy and costsaving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylbenzenes,styrene,in 1-allyl-3-methylimidazolium tetrafluoroborate ([AMIM][BF4]) and 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6]), 1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF4]) and [MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure parameters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.

  15. A three-stage stochastic optimization model for the Brazilian biodiesel supply chain

    Directory of Open Access Journals (Sweden)

    Pedro Senna

    2016-01-01

    Full Text Available Abstract The Brazilian program for biodiesel use highlights the production of biodiesel from castor seeds. Biodiesel is a non-polluting energy source that has the potential to promote prosperity by creating jobs in poor regions of Brazil. However, the infrastructure, logistics, and proper facilities are lacking. A variety of approaches to optimizing the biodiesel supply chain have been proposed. The goal is to minimize the grain storage and transportation costs. This paper presents a comparison between a two-stage model and a multistage (three-stage stochastic model to optimize the biodiesel supply chain. The comparison between these formulations shows that the flexibility gain provided by the multistage model results in a lower total logistic cost. The optimum for the three-stage model was 7,700,019 (BRL, compared to 8,628,002 (BRL for the two-stage model, representing a savings of 927,983 (BRL. We highlight that this model offers a real solution for castor supply chain design (considering uncertainty in the Brazilian semiarid region, which is a poorer region of the country, thus making cost reduction mandatory.

  16. A SURVEY OF STACKELBERG DIFFERENTIAL GAME MODELS IN SUPPLY AND MARKETING CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Xiuli HE; Ashutosh PRASAD; Suresh P. SETHI; Genaro J. GUTIERREZ

    2007-01-01

    Stackelberg differential game models have been used to study sequential decision making in noncooperative games in diverse fields. In this paper, we survey recent applications of Stackelberg differential game models to the supply chain management and marketing channels literatures. A common feature of these applications is the specification of the game structure: a decentralized channel composed of a manufacturer and independent retailers, and a sequential decision procedure with demand and supply dynamics and coordination issues. In supply chain management, Stackelberg differential games have been used to investigate inventory issues, wholesale and retail pricing strategies, and outsourcing in dynamic environments. The underlying demand typically has growth dynamics or seasonal variation. In marketing, Stackelberg differential games have been used to model cooperative advertising programs, store brand and national brand advertising strategies, shelf space allocation, and pricing and advertising decisions. The demand dynamics are usually extensions of the classical advertising capital models or sales-advertising response models. We begin by explaining the Stackelberg differential game solution methodology and then provide a description of the models and results reported in the literature.

  17. Development of Thermophysical Hydrocarbon Wastes Pyrolysis Model (in the Case of Wood)

    Science.gov (United States)

    Shantarin, V. D.; Zemenkova, M. Yu; Zemenkov, Yu D.

    2016-10-01

    The article is devoted to solving environmental problems in the operation in oil and gas industry objects. Reduction of environmental damage by pollution with hydrocarbons can be achieved by disposing oil-contaminated hydrocarbon wastes, using high-temperature pyrolysis process. Authors proposed a recycling method by which in the output there generates the maximum amount of syngas, which, in its turn, is an expensive resource

  18. Modeling hydrocarbon biodegradation in tidal aquifers with water-saturation and heat inhibition effects

    Science.gov (United States)

    El-Kadi, Aly I.

    2001-09-01

    A model is developed for hydrocarbon biodegradation, which includes saturated and unsaturated flow, multi-species transport, heat transport, and bacterial growth processes. Numerical accuracy of the model was tested against analytical solutions. The model was also verified against laboratory results for a saturated-flow problem and reasonable match was obtained. Expressions are proposed for inhibition due to water content and temperature fluctuations. Bioactivities under cyclic water content variation were studied under no-flow conditions. A quantitative approach was used to reconcile some of the apparent contradictory conclusions regarding the efficiency of biodegradation of soils under wetting and drying conditions. The efficiency depends on the nature of the oxygenation process. For cases involving the presence of dissolved oxygen and the absence of O 2 vapor, subjecting the soil to constant water content close to its optimal value for degradation is most efficient. However, wetting and drying can enhance degradation if O 2 is only provided through aeration or direct contact between air and the medium. Also presented are the results of a typical field application of the model and a discussion of the effects of tides, saturation inhibition, and heat inhibition. Other inhibition factors, such as pH or salinity, can be easily incorporated in the formulation. The quantitative approach developed here can be used in assessing bioremediation not only in tidal aquifers but also in areas where water-table or temperature effects are of significance. The approach can be useful in the design of remediation strategies under water-flow or no-flow conditions involving water content and temperature fluctuations.

  19. Introducing a model for competitiveness of suppliers in supply chain through game theory approach

    Directory of Open Access Journals (Sweden)

    Hengameh Cighary Deljavan

    2012-10-01

    Full Text Available Cighary Deljavan and Fariba Sadeghi PDF (300 KAbstract: The purpose of the present study is to introduce a model for competitiveness of suppliers in supply chain through game theory approach in one of the automobile companies of Iran. In this study, the game is based on price and non-price factors and this company is going to estimate the real profit obtained from collaboration with each of supply chain members. This happens by considering the governing competitive condition based on game theory before entering a bit for purchase of α piece as spare part among 8 companies supplying this piece as the supply chain members. According to experts in this industry, the quality is the main non-price competitiveness factor after price. In the current research models, the model introduced by Lu and Tsao (2011 [Lu, J.C., Tsao, Y.C., & Charoensiriwath, C. (2011. Competition Under manufacturer Service and retail price. Economic Modeling, 28,1256-1264.] with two manufacturers- one distributer, being appropriate for the research data, has been considered as the basis and implemented for case study and then it has been extended to n-manufacturers-one common retailer. Following price elasticity of demand, potential size of market or maximum product demand, retailer price, production price, wholesale price, demand amount, manufacturer and retailer profit are estimated under three scenario of manufacturer Stackelberg, Retailer Sackelberg and Vertical Nash. Therefore, by comparing them, price balance points and optimum level of services are specified and the better optimum scenario can be determined. Sensitivity analysis is performed for new model and manufacturers are ranked based on manufacture profit, Retailer profit and customer satisfaction. Finally, in this research in addition to introducing-person game model, customer satisfaction, which has been presented in the previous models as a missed circle are analyzed.

  20. Modelling and simulation of the integration of the supply chain of forward and backward type

    Directory of Open Access Journals (Sweden)

    Roman Domański

    2015-03-01

    Full Text Available Background: The integration, besides synergy and convergence, is regarded as a leading orientation in modern logistics. The connection of various participants within supply chains enables the integration of actions and allows to fulfill growing customers' demands in an effective and economically efficient way.  In times of a concept of the balanced development, growing interest in utilization of recycled material, connected with possibilities to consolidate  logistic activities, can be observed. According to the scientific literature (integration models as well as practical business cases, supply chains of forward and backward type (two-directional are the area of logistics of the intensive development.    Material and methods: The paper presents the Authors' model and methodology of modeling of the integration of supply chains, which realizes the flows of forward and backward type (two-directions. The empirical material was obtained during modeling and simulation of processes in the environment of iGrafx Process 2013 for Six Sigma with the support of Minitab 17 (for planning of experiments.  The method of the verification of statistical hypotheses was used. As a first step, the correlation between the level of the integration and the global service level for the supply chain was conducted using the method of Pearson's coefficient. The test of relevance of correlation coefficient was conducted by the use of t-distribution method. Then the verification of statistical hypotheses was made, based on the method using the Z-statistics. Results: The obtained results indicate clearly the strong relationship between the level of the integration of a supply chain and the obtained service level (values of Pearson's correlation coefficient and results of t-test. The detailed statistical researches of authors indicate that the increased level of the integration leads to the increase of the average value of service level coefficient (results of Z

  1. River longitudinal profiles and bedrock incision models: Stream power and the influence of sediment supply

    Science.gov (United States)

    Sklar, Leonard; Dietrich, William E.

    The simplicity and apparent mechanistic basis of the stream power river incision law have led to its wide use in empirical and theoretical studies. Here we identify constraints on its calibration and application, and present a mechanistic theory for the effects of sediment supply on incision rates which spotlights additional limitations on the applicability of the stream power law. On channels steeper than about 20%, incision is probably dominated by episodic debris flows, and on sufficiently gentle slopes, sediment may bury the bedrock and prevent erosion. These two limits bound the application of the stream power law and strongly constrain the possible combination of parameters in the law. In order to avoid infinite slopes at the drainage divide in numerical models of river profiles using the stream power law it is commonly assumed that the first grid cell is unchanneled. We show, however, that the size of the grid may strongly influence the calculated equilibrium relief. Analysis of slope-drainage area relationships for a river network in a Northern California watershed using digital elevation data and review of data previously reported by Hack reveal that non-equilibrium profiles may produce well defined slope-area relationships (as expected in equilibrium channels), but large differences between tributaries may point to disequilibrium conditions. To explore the role of variations in sediment supply and transport capacity in bedrock incision we introduce a mechanistic model for abrasion of bedrock by saltating bedload. The model predicts that incision rates reach a maximum at intermediate levels of sediment supply and transport capacity. Incision rates decline away from the maximum with either decreasing supply (due to a shortage of tools) or increasing supply (due to gradual bed alluviation), and with either decreasing transport capacity (due to less energetic particle movement) or increasing transport capacity (due less frequent particle impacts per unit bed

  2. A 4D synchrotron X-ray tomography study of the formation of hydrocarbon migration pathways in heated organic-rich shale

    CERN Document Server

    Panahi, Hamed; Renard, Francois; Mazzini, Adriano; Scheibert, Julien; Dysthe, Dag Kristian; Jamtveit, Bjorn; Malthe-Sørenssen, Anders; Meakin, Paul

    2014-01-01

    Recovery of oil from oil shales and the natural primary migration of hydrocarbons are closely related processes that have received renewed interests in recent years because of the ever tightening supply of conventional hydrocarbons and the growing production of hydrocarbons from low permeability tight rocks. Quantitative models for conversion of kerogen into oil and gas and the timing of hydrocarbon generation have been well documented. However, lack of consensus about the kinetics of hydrocarbon formation in source rocks, expulsion timing and how the resulting hydrocarbons escape from or are retained in the source rocks motivates further investigation. In particular, many mechanisms for the transport of hydrocarbons from the source rocks in which they are generated into adjacent rocks with higher permeabilities and smaller capillary entry pressures have been proposed, and a better understanding of this complex process (primary migration) is needed. To characterize these processes it is imperative to use the ...

  3. Regime switches induced by supply-demand equilibrium: a model for power-price dynamics

    Science.gov (United States)

    Mari, Carlo; Tondini, Daniela

    2010-11-01

    Regime-switching models can be used to describe stochastic movements of electricity prices in deregulated markets. This paper shows that regime-switching dynamics arise quite naturally in an equilibrium context in which the functional form of the supply curve is described by a two-state Markov process. This mechanism is responsible for random switches between regimes and it allows one to describe the main features of the price-formation process. With the interplay between demand and supply, the proposed methodology can be used to capture shortages in electricity generation, forced outages, and peaks in electricity demand. As an example of application, a two-regime model specification is proposed, and it will be shown that the empirical analysis, performed by estimating using the model on the California power market, offers an interesting agreement with observed data.

  4. Equilibrium Model of Discrete Dynamic Supply Chain Network with Random Demand and Advertisement Strategy

    Directory of Open Access Journals (Sweden)

    Guitao Zhang

    2014-01-01

    Full Text Available The advertisement can increase the consumers demand; therefore it is one of the most important marketing strategies in the operations management of enterprises. This paper aims to analyze the impact of advertising investment on a discrete dynamic supply chain network which consists of suppliers, manufactures, retailers, and demand markets associated at different tiers under random demand. The impact of advertising investment will last several planning periods besides the current period due to delay effect. Based on noncooperative game theory, variational inequality, and Lagrange dual theory, the optimal economic behaviors of the suppliers, the manufactures, the retailers, and the consumers in the demand markets are modeled. In turn, the supply chain network equilibrium model is proposed and computed by modified project contraction algorithm with fixed step. The effectiveness of the model is illustrated by numerical examples, and managerial insights are obtained through the analysis of advertising investment in multiple periods and advertising delay effect among different periods.

  5. Humanitarian relief supply chain: a multi-objective model and solution

    Indian Academy of Sciences (India)

    ADITYA JHA; DAMODAR ACHARYA; M K TIWARI

    2017-07-01

    This paper models a humanitarian relief chain that includes a relief goods supply chain and an evacuation chain in case of a natural disaster. Optimum network flow is studied for both the chains by considering three conflicting objectives, namely demand satisfaction in relief chain, demand satisfaction in evacuation chain and overall logistics cost.The relief goods supply chain consists of three echelons: suppliers, relief camps and affected areas. The evacuation chain consists of two echelons: evacuation camps and affected areas. The model has been made more resilient by considering multiple paths between any two locations and disruptionof camps and paths due to natural factors. The Mixed Integer Programming problem has been solved using NSGA-III and results have been compared to those from benchmark algorithms. The model has been successfully tested on generated real-life-like data.

  6. A dynamic optimization model of an integrated coal supply chain system and its application

    Institute of Scientific and Technical Information of China (English)

    PENG Hong-jun; ZHOU Mei-hua; LIU Man-zhi; ZHANG Yu; HUANG Yan-bo

    2009-01-01

    Various nodes, logistics, capital flows, and information flows are required to make systematic decisions concerning the operation of an integrated coal supply system. We describe a quantitative analysis of such a system. A dynamic optimization model of the supply chain is developed. It has achieved optimal system profit under conditions guaranteeing a certain level of customer satisfaction. Applying this model to coal production of the Xuzhou coal mines allows recommendations for a more systematic use of washing and processing, transportation and sale resources for commercial co al production to be made. The results show that this model, which is scientific and effective, has an important value for making reasonable decisions related to complex coal enterprises.

  7. AIREBO-M: A reactive model for hydrocarbons at extreme pressures

    Energy Technology Data Exchange (ETDEWEB)

    O’Connor, Thomas C., E-mail: toconnor@jhu.edu; Robbins, Mark O., E-mail: Mark.O.Robbins@jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Andzelm, Jan, E-mail: jan.w.andzelm.civ@mail.mil [Macromolecular Science and Technology Branch, U.S. Army Research Laboratory, Aberdeen, Maryland 21005 (United States)

    2015-01-14

    The Adaptive Intermolecular Reactive Empirical Bond Order potential (AIREBO) for hydrocarbons has been widely used to study dynamic bonding processes under ambient conditions. However, its intermolecular interactions are modeled by a Lennard-Jones (LJ) potential whose unphysically divergent power-law repulsion causes AIREBO to fail when applied to systems at high pressure. We present a modified potential, AIREBO-M, where we have replaced the singular Lennard-Jones potential with a Morse potential. We optimize the new functional form to improve intermolecular steric repulsions, while preserving the ambient thermodynamics of the original potentials as much as possible. The potential is fit to experimental measurements of the layer spacing of graphite up to 14 GPa and first principles calculations of steric interactions between small alkanes. To validate AIREBO-M’s accuracy and transferability, we apply it to a graphite bilayer and orthorhombic polyethylene. AIREBO-M gives bilayer compression consistent with quantum calculations, and it accurately reproduces the quasistatic and shock compression of orthorhombic polyethlyene up to at least 40 GPa.

  8. Influence of the heterogeneous reaction HCl + HOCl on an ozone hole model with hydrocarbon additions

    Science.gov (United States)

    Elliott, Scott; Cicerone, Ralph J.; Turco, Richard P.; Drdla, Katja; Tabazadeh, Azadeh

    1994-02-01

    Injection of ethane or propane has been suggested as a means for reducing ozone loss within the Antarctic vortex because alkanes can convert active chlorine radicals into hydrochloric acid. In kinetic models of vortex chemistry including as heterogeneous processes only the hydrolysis and HCl reactions of ClONO2 and N2O5, parts per billion by volume levels of the light alkanes counteract ozone depletion by sequestering chlorine atoms. Introduction of the surface reaction of HCl with HOCl causes ethane to deepen baseline ozone holes and generally works to impede any mitigation by hydrocarbons. The increased depletion occurs because HCl + HOCl can be driven by HOx radicals released during organic oxidation. Following initial hydrogen abstraction by chlorine, alkane breakdown leads to a net hydrochloric acid activation as the remaining hydrogen atoms enter the photochemical system. Lowering the rate constant for reactions of organic peroxy radicals with ClO to 10-13 cm3 molecule-1 s-1 does not alter results, and the major conclusions are insensitive to the timing of the ethane additions. Ignoring the organic peroxy radical plus ClO reactions entirely restores remediation capabilities by allowing HOx removal independent of HCl. Remediation also returns if early evaporation of polar stratospheric clouds leaves hydrogen atoms trapped in aldehyde intermediates, but real ozone losses are small in such cases.

  9. Environmental Capacity of Petroleum Hydrocarbon Pollutants in Jiaozhou Bay, China: Modeling and Calculation

    Institute of Scientific and Technical Information of China (English)

    LI Keqiang; SU Ying; YING Jun; WANG Xiulin; MU Jinbo

    2013-01-01

    An environmental capacity model for the petroleum hydrocarbon pollutions (PHs) in Jiaozhou Bay is constructed based on field surveys,mesocosm,and parallel laboratory experiments.Simulated results of PHs seasonal successions in 2003 match the field surveys of Jiaozhou Bay resaonably well with a highest value in July.The Monte Carlo analysis confirms that the variation of PHs concentration significantly correlates with the river input.The water body in the bay is reasonably subjected to self-purification processes,such as volatilization to the atmosphere,biodegradation by microorganism,and transport to the Yellow Sea by water exchange.The environmental capacity of PHs in Jiaozhou Bay is 1500 tons per year IF the seawater quality criterion (Grade Ⅰ/Ⅱ,0.05 mgL-1) in the region is to be satisfied.The contribution to self-purification by volatilization,biodegradation,and transport to the Yellow Sea accounts for 48%,28%,and 23%,respectively,which make these three processes the main ways of PHs purification in Jiaozhou Bay.

  10. Investigating polycyclic aromatic hydrocarbons profiles in higher plants using statistical models.

    Science.gov (United States)

    Sojinu, O Samuel; Sonibare, O Oluwadayo; Gayawan, Ezra

    2013-01-01

    Thirty-six higher plants sampled from Olomoro, Irri, Uzere, and Oginni exploration sites in the Niger Delta region of Nigeria were subjected to GC/MS analysis to assess the occurrence, distribution and profiles of polycyclic aromatic hydrocarbons (PAHs) contained in them. The sigma28PAHs ranged from 335 to 3094 ng/g. The results of the nonparametric regression models showed that PAHs concentration in a plant cannot be used in isolation to deduce the total PAHs concentration in soils hosting the plant since PAHs concentration in a plant is influenced by the presence (or absence) of other plants in that location. A combination of Factor analysis (FA) and principal component analysis (PCA) were used to recognize PAHs concentration patterns among the plants in the studied locations and individual PAHs compounds. Woody annuals and perennial plants formed similar patterns in Oginni and Irri locations. Three main clusters were formed by all the compounds with naphthalene and 2-methylnaphthalene standing as outliers in all the four locations.

  11. Environmental capacity of petroleum hydrocarbon pollutants in Jiaozhou Bay, China: Modeling and calculation

    Science.gov (United States)

    Li, Keqiang; Su, Ying; Ying, Jun; Wang, Xiulin; Mu, Jinbo

    2013-03-01

    An environmental capacity model for the petroleum hydrocarbon pollutions (PHs) in Jiaozhou Bay is constructed based on field surveys, mesocosm, and parallel laboratory experiments. Simulated results of PHs seasonal successions in 2003 match the field surveys of Jiaozhou Bay resaonably well with a highest value in July. The Monte Carlo analysis confirms that the variation of PHs concentration significantly correlates with the river input. The water body in the bay is reasonably subjected to self-purification processes, such as volatilization to the atmosphere, biodegradation by microorganism, and transport to the Yellow Sea by water exchange. The environmental capacity of PHs in Jiaozhou Bay is 1500 tons per year IF the seawater quality criterion (Grade I/II, 0.05 mgL-1) in the region is to be satisfied. The contribution to self-purification by volatilization, biodegradation, and transport to the Yellow Sea accounts for 48%, 28%, and 23%, respectively, which make these three processes the main ways of PHs purification in Jiaozhou Bay.

  12. A Multi-Objective, Hub-and-Spoke Supply Chain Design Model for Densified Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Md. S. Roni; Kara G. Cafferty; Sandra D. Eksioglu

    2014-06-01

    In this paper we propose a model to design the supply chain for densified biomass. Rail is typically used for longhaul, high-volume shipment of densified biomass. This is the reason why a hub-and-spoke network structure is used to model this supply chain. The model is formulated as a multi-objective, mixed-integer programing problem under economic, environmental, and social criteria. The goal is to identify the feasibility of meeting the Renewable Fuel Standard (RFS) by using biomass for production of cellulosic ethanol. The focus is not just on the costs associated with meeting these standards, but also exploring the social and environmental benefits that biomass production and processing offers by creating new jobs and reducing greenhouse gas (GHG) emissions. We develop an augmented ?-constraint method to find the exact Pareto solution to this optimization problem. We develop a case study using data from the Mid-West. The model identifies the number, capacity and location of biorefineries needed to make use of the biomass available in the region. The model estimates the delivery cost of cellulosic ethanol under different scenario, the number new jobs created and the GHG emission reductions in the supply chain.

  13. A Multi-Objective, Hub-and-Spoke Supply Chain Design Model For Densified Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Md S. Roni; Sandra Eksioglu; Kara G. Cafferty

    2014-06-01

    In this paper we propose a model to design the supply chain for densified biomass. Rail is typically used for long-haul, high-volume shipment of densified biomass. This is the reason why a hub-and-spoke network structure is used to model this supply chain. The model is formulated as a multi-objective, mixed-integer programing problem under economic, environmental, and social criteria. The goal is to identify the feasibility of meeting the Renewable Fuel Standard (RFS) by using biomass for production of cellulosic ethanol. The focus in not just on the costs associated with meeting these standards, but also exploring the social and environmental benefits that biomass production and processing offers by creating new jobs and reducing greenhouse gas (GHG) emissions. We develop an augmented ?-constraint method to find the exact Pareto solution to this optimization problem. We develop a case study using data from the Mid-West. The model identifies the number, capacity and location of biorefineries needed to make use of the biomass available in the region. The model estimates the delivery cost of cellulosic ethanol under different scenario, the number new jobs created and the GHG emission reductions in the supply chain.

  14. European oil product supply modelling; Modelisation de l`offre de produits petroliers en Europe

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Antonin, V

    1998-12-11

    Over the last few years, trends in European oil product consumption (in terms of level as structure and quality) has important implications of the refining industry. In this context, the purpose of this thesis consists in building a mathematical programming model applied to the European refineries in order to determine oil product supply prices, European refining industry investments and oil product exchanges of the European Union. The first part presents the reason for our choice for a long-term aggregate multi-refineries linear programming model, based on European refineries characteristics and the objectives of our model. Its dual properties are studied in detail and we focus particularly on the European exchange modelling. In the second part, an analysis of the European refining trends leads us to identify parameters and variables of the model that are essential to the aggregate representation of the European oil product supply. The third part is devoted to the use of this model, regarding two scenarios of increasingly stringent specifications for gasoline and diesel oil. Our interest for these products is due to their important share of the European oil product consumption and the not insignificant responsibility of the transport sector for atmospheric pollution. Finally, in order to have the use of an overall picture of the European refining industry, we build a regression model summarizing, though a few equations, the main relations between the major endogenous and exogenous variables o the LP model. Based on pseudo-data, this kind of model provides a simple and robust representation of the oil product supply. But a more specialized analysis of the refining industry operations, turning on a technical assessment of processing units, is reliant on the use of an optimization model such as the model we have built. (author) 102 refs.

  15. Analysis of Supply Chain Model of Agricultural Products and Quality Safety——A Case Study of Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper analyses the supply chain models of four types of agricultural products,namely fruits and vegetables,poultry,aquatic products and dairy,and the food safety problems arising from the links of supply chain.In view of different models,corresponding suggestions are put forward to ensure the quality safety of agricultural products in Heilongjiang Province.

  16. Reduced kinetic mechanism of n-heptane oxidation in modeling polycyclic aromatic hydrocarbon formation in opposed-flow diffusion flames

    Institute of Scientific and Technical Information of China (English)

    Beijing ZHONG; Jun XI

    2008-01-01

    A reduced mechanism, which could couple with the multidimensional computational fluid dynamics code for quantitative description of a reacting flow, was developed for chemical kinetic modeling of polycyclic aro-matic hydrocarbon formation in an opposed-flow dif-fusion flame. The complete kinetic mechanism, which comprises 572 reactions and 108 species, was reduced to a simplified mechanism that includes only 83 reactions and 56 species through sensitivity analysis. The results computed via this reduced mechanism are nearly indistin-guishable from those via the detailed mechanism, which demonstrate that the model based on this reduced mech-anism can properly describe n-heptane oxidation chem-istry and quantitatively predict polycyclic aromatic hydrocarbon (such as benzene, naphthalene, phenan-threne and pyrene) formation in opposed-flow diffusion flames.

  17. Tectonic subsidence modelling and Gondwana source rock hydrocarbon potential, Northwest Bangladesh modelling of Kuchma, Singra and Hazipur wells

    Energy Technology Data Exchange (ETDEWEB)

    Frielingsdorf, J. [Shell Petroleum Development Company, Nigeria Limited, P.O. Box 23, Port Harcourt, Rivers State (Nigeria); Aminul Islam, Sk.; Mizanur Rahman, Md. [BAPEX, Bangladesh Petroleum Exploration and Production Ltd., Shahjalal Tower, 80/A-B Siddeshwari Circular Road, Dhaka 1217 (Bangladesh); Block, Martin [Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover (Germany); Golam Rabbani, Md. [Norwegian University of Science and Technology (NTNU), 7491 Trondheim (Norway)

    2008-06-15

    The northwestern part of Bangladesh is in terms of hydrocarbon exploration still under-explored. This paper presents the basin development from a structural point of view and includes the results of thermal and maturity modelling using numerical tools of basin modelling. One regional seismic section and three exploration wells have been investigated to unravel a conceptual model for the subsidence and thermal history of the region. According to the findings it is very likely that up to 2900 m of Triassic/Jurassic and partly Permian sediments have been eroded prior to the break-up of Gondwana. During continental break-up a peak heat flow is considered. This was necessary for calibrating maturity profiles using vitrinite reflectance (VR) derived from modelled wells. A significant gas generation phase during Lower Jurassic is predicted. At modelled well locations, although renewed subsidence occurred during Tertiary to present day, a second phase of gas generation has not occurred, as past maximum temperatures were not exceeded. According to the interpreted regional seismic sections in the region, the area southeast of the 'Hinge Zone' can be regarded as the main kitchen area for gas generation from the Gondwana source rock. The petroleum system in the northwestern part of Bangladesh remains high risk due to uncertainties in source rock distribution and generation. (author)

  18. Flexible scheduling model of crude oil operations under crude supply disturbance

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Today’s changeable market and resultant disturbance of crude oil supply require agile and flexible scheduling of crude oil operation. The objective of flexible scheduling is to keep stable crude oil op-eration and satisfy production demands under the circumstances of supply disturbance. In this paper, a new mixed integer non-linear programming (MINLP) formulation is set up for crude oil scheduling firstly, and then some heuristic rules worked out by some experts are proposed to linearize bilinear terms and prefix some binary variables in the MINLP model. These rules not only reduce the complexity of the MINLP model, but also can be used to solve the scheduling problems in various conditions. In case study, the new model with heuristic rules and the best models reported in the literature are com-pared and evaluated in three benchmark examples in the normal situation, and then three abnormal situations of supply delay are considered based on the new approach. The results of case study show that the new flexible approach can handle crude oil scheduling problems efficiently in both normal and abnormal conditions.

  19. A new fuzzy mathematical model for green supply chain network design

    Directory of Open Access Journals (Sweden)

    Mohsen Sadegh Amalnick

    2017-01-01

    Full Text Available The environmental changes caused by industrial activities have spurred a significant interest in designing supply chain networks by considering environmental issues such as CO2 emission. The pivotal role of taking uncertainty and risk into account in closed-loop supply chain networks has induced numerous researchers and practitioners to develop appropriate decision making tools to cope with these issues in such networks. To design a supply chain regarding environmental impacts under uncertainty of the input data and to cope with the operational risks, this paper proposes a multi objective possibilistic optimization model. The proposed model minimizes traditional costs such as cost of products shipment, purchasing machines and so on, as well as minimizing the environmental impact, and as a results strikes a balance between the two objective functions. Furthermore, in order to solve the proposed multi objective fuzzy mathematical programming model, an interactive fuzzy solution approach is applied. Numerical experiments are used to prove the applicability and feasibility of the developed possibilistic programming model and the usefulness of the applied hybrid solution approach.

  20. Flexible scheduling model of crude oil operations under crude supply disturbance

    Institute of Scientific and Technical Information of China (English)

    PAN Ming; QIAN Yu; LI Xiu-Xi

    2009-01-01

    Today's ohangeable market and resultant disturbance of orude oil supply require agile and flexible scheduling of crude oil operation. The objective of flexible scheduling is to keep stable crude oil op-eration and satisfy production demands under the circumstances of supply disturbance. In this paper, a new mixed integer non-linear programming (MINLP) formulation is set up for crude oil scheduling firstly, and then some heuristic rules worked out by some experts are proposed to linearize bilinear terms and prefix some binary variables in the MINLP model. These rules not only reduce the complexity of the MINLP model, but also can be used to solve the scheduling problems in various conditions. In oase study, the new model with heuristic rules and the best models reported in the literature are com-pared and evaluated in three benchmark examples in the normal situation, and then three abnormal situations of supply delay are considered based on the new approach. The results of case study show that the new flexible approach can handle crude oil scheduling problems efficiently in both normal and abnormal conditions.

  1. Integrated Location-Production-Distribution Planning in a Multiproducts Supply Chain Network Design Model

    Directory of Open Access Journals (Sweden)

    Vincent F. Yu

    2015-01-01

    Full Text Available This paper proposes integrated location, production, and distribution planning for the supply chain network design which focuses on selecting the appropriate locations to build a new plant and distribution center while deciding the production and distribution of the product. We examine a multiechelon supply chain that includes suppliers, plants, and distribution centers and develop a mathematical model that aims at minimizing the total cost of the supply chain. In particular, the mathematical model considers the decision of how many plants and distribution centers to open and where to open them, as well as the allocation in each echelon. The LINGO software is used to solve the model for some problem cases. The study conducts various numerical experiments to illustrate the applicability of the developed model. Results show that, in small and medium size of problem, the optimal solution can be found using this solver. Sensitivity analysis is also conducted and shows that customer demand parameter has the greatest impact on the optimal solution.

  2. The reference model of supply chain operational controlling in value management

    Directory of Open Access Journals (Sweden)

    2010-03-01

    Full Text Available The systemic approach of the controlling function to supporting the operations management results from its complex analysis of the supply chain business and operating results and from influencing the operations management factors - products, processes and resources that determine the achieved result (revenues, costs, profitability and assets turnover as well as the return on invested capital. All product features which stand for customer value and its competitiveness are the basis for designing, planning and controlling the interconnected processes responsible for manufacturing and delivery of products. The effectiveness of methods applied in developing products, processes and resources depends on the precise analysis and appraisal of the operating conditions that justify their application. Supporting the operations management, focused on the product value and improving the company's financial result, apart from financial, technical and economic analyses requires transferring the product value to activities control methods and to developing the resources in the product supply chain already at the stage of planning. As a result of an analysis of requirements supporting the development of processes and resources in the supply chain, a reference model of operational controlling in product value management was developed. The multicriterion selection and appropriate application of material flow management methods in the supply chain is each time preceded by an operating and financial analysis as well as by an appraisal of operating conditions that influence the choice of control methods.

  3. Modelling and Risk Management in the Offshore and Marine Industry Supply Chain

    Directory of Open Access Journals (Sweden)

    Carman Lee

    2012-03-01

    Full Text Available Supply chain risk management is primarily a process that involves the identification, assessment and mitigation of risks that arise in a particular supply chain system. Pertaining to that, the offshore and marine industry is one of the many industries that have seldom received much consideration when it comes to management of the supply chain system. The rig building facet of the offshore and marine industry was thus chosen as the main focus of the project to manage the risks that arise in a particular oil rig building project. A risk mitigation plan framework was proposed to act as a guideline to identify as much risk as possible, eliminate trivial ones, and subsequently, prioritizing the remaining ones. The final step involves the formulation of a mathematical model based on the selected risk. In this case, the risk of raw material price fluctuation is studied. The demonstration of the Monte Carlo simulation using the Risk Solver program was also done to quantify the risks. Two case scenarios were then developed along with the implementation of risk management techniques in order to observe the effectiveness of the risk management of the overall rig building supply chain.

  4. Metabolic modelling to support long term strategic decisions on water supply systems

    Science.gov (United States)

    Ciriello, Valentina; Felisa, Giada; Lauriola, Ilaria; Pomanti, Flavio; Di Federico, Vittorio

    2017-04-01

    Water resources are essential for the economic development and sustenance of anthropic activities belonging to the civil, agricultural and industrial sectors. Nevertheless, availability of water resources is not uniformly distributed in space and time. Moreover, the increasing water demand, mainly due to population growth and expansion of agricultural crops, may cause increasing water stress conditions, if combined with the effects of climate change. Under these circumstances, it is necessary to improve the resilience of water supply systems both in terms of infrastructures and environmental compliance. Metabolic modelling approaches represent a flexible tool able to provide support to decision making in the long term, based on sustainability criteria. These approaches mimic the water supply network through a set of material and energy fluxes that interact and influence each other. By analyzing these fluxes, a suite of key performance indicators is evaluated in order to identify which kind of interventions may be applied to increase the sustainability of the system. Here, we adopt these concepts to analyze the water supply network of Reggio-Emilia (Italy) which is supported by water withdrawals from both surface water and groundwater bodies. We analyze different scenarios, including possible reduction of water withdrawals from one of the different sources as a consequence of a decrease in water availability under present and future scenarios. On these basis, we identify preventive strategies for a dynamic management of the water supply system.

  5. Self-Supply as a Complementary Water Services Delivery Model in Ethiopia

    Directory of Open Access Journals (Sweden)

    John Butterworth

    2013-10-01

    Full Text Available Self-supply, where households invest to develop their own easily-accessible water supplies, is identified as an alternative service delivery model that is potentially complementary to more highly subsidised community-level provision. The approach is widespread in Ethiopia with family wells bringing additional benefits that are in line with wider government objectives, such as supporting small-scale irrigation. However, two recent studies show the current performance of traditional or family wells to be far below potential with most sources providing unsafe water in the absence of adequate protection. Wider formal recognition of Self-supply in policy and the development of the government-led Self-supply Acceleration Programme (SSAP aim to extend access and improve aspects of performance including water quality. However, a key finding of the paper is that successful uptake of this programme requires a transformation in the attitudes of donor agencies and the roles of government regional- and woreda-level staff, amongst others. Necessary shifts in mindsets and revision of planning mechanisms, as well as the day-to-day operational support requirements, represent a challenge for an under-resourced sector. Other household-focused development interventions such as Community-led Total Sanitation (CLTS and Household Water Treatment and Storage (HWTS face some similar challenges, so the processes for the development of one approach could help in the scaling up of all.

  6. A COMPARATIVE STUDY OF SIMULATION AND TIME SERIES MODEL IN QUANTIFYING BULLWHIP EFFECT IN SUPPLY CHAIN

    Directory of Open Access Journals (Sweden)

    T. V. O. Fabson

    2011-11-01

    Full Text Available Bullwhip (or whiplash effect is an observed phenomenon in forecast driven distribution channeland careful management of these effects is of great importance to managers of supply chain.Bullwhip effect refers to situations where orders to the suppliers tend to have larger variance thansales to the buyer (demand distortion and the distortion increases as we move up the supply chain.Due to the fact that demand of customer for product is unstable, business managers must forecast inorder to properly position inventory and other resources. Forecasts are statistically based and in mostcases, are not very accurate. The existence of forecast errors made it necessary for organizations tooften carry an inventory buffer called “safety stock”. Moving up the supply chain from the end userscustomers to raw materials supplier there is a lot of variation in demand that can be observed, whichcall for greater need for safety stock.This study compares the efficacy of simulation and Time Series model in quantifying the bullwhipeffects in supply chain management.

  7. Simulation and Modeling Efforts to Support Decision Making in Healthcare Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Eman AbuKhousa

    2014-01-01

    Full Text Available Recently, most healthcare organizations focus their attention on reducing the cost of their supply chain management (SCM by improving the decision making pertaining processes’ efficiencies. The availability of products through healthcare SCM is often a matter of life or death to the patient; therefore, trial and error approaches are not an option in this environment. Simulation and modeling (SM has been presented as an alternative approach for supply chain managers in healthcare organizations to test solutions and to support decision making processes associated with various SCM problems. This paper presents and analyzes past SM efforts to support decision making in healthcare SCM and identifies the key challenges associated with healthcare SCM modeling. We also present and discuss emerging technologies to meet these challenges.

  8. Simulation and modeling efforts to support decision making in healthcare supply chain management.

    Science.gov (United States)

    AbuKhousa, Eman; Al-Jaroodi, Jameela; Lazarova-Molnar, Sanja; Mohamed, Nader

    2014-01-01

    Recently, most healthcare organizations focus their attention on reducing the cost of their supply chain management (SCM) by improving the decision making pertaining processes' efficiencies. The availability of products through healthcare SCM is often a matter of life or death to the patient; therefore, trial and error approaches are not an option in this environment. Simulation and modeling (SM) has been presented as an alternative approach for supply chain managers in healthcare organizations to test solutions and to support decision making processes associated with various SCM problems. This paper presents and analyzes past SM efforts to support decision making in healthcare SCM and identifies the key challenges associated with healthcare SCM modeling. We also present and discuss emerging technologies to meet these challenges.

  9. Two-echelon competitive integrated supply chain model with price and credit period dependent demand

    Science.gov (United States)

    Pal, Brojeswar; Sankar Sana, Shib; Chaudhuri, Kripasindhu

    2016-04-01

    This study considers a two-echelon competitive supply chain consisting of two rivaling retailers and one common supplier with trade credit policy. The retailers hope that they can enhance their market demand by offering a credit period to the customers and the supplier also offers a credit period to the retailers. We assume that the market demand of the products of one retailer depends not only on their own market price and offering a credit period to the customers, but also on the market price and offering a credit period of the other retailer. The supplier supplies the product with a common wholesale price and offers the same credit period to the retailers. We study the model under a centralised (integrated) case and a decentralised (Vertical Nash) case and compare them numerically. Finally, we investigate the model by the collected numerical data.

  10. Customer involvement in greening the supply chain: an interpretive structural modeling methodology

    Science.gov (United States)

    Kumar, Sanjay; Luthra, Sunil; Haleem, Abid

    2013-04-01

    The role of customers in green supply chain management needs to be identified and recognized as an important research area. This paper is an attempt to explore the involvement aspect of customers towards greening of the supply chain (SC). An empirical research approach has been used to collect primary data to rank different variables for effective customer involvement in green concept implementation in SC. An interpretive structural-based model has been presented, and variables have been classified using matrice d' impacts croises- multiplication appliqué a un classement analysis. Contextual relationships among variables have been established using experts' opinions. The research may help practicing managers to understand the interaction among variables affecting customer involvement. Further, this understanding may be helpful in framing the policies and strategies to green SC. Analyzing interaction among variables for effective customer involvement in greening SC to develop the structural model in the Indian perspective is an effort towards promoting environment consciousness.

  11. Statistical Modeling of Occupational Exposure to Polycyclic Aromatic Hydrocarbons Using OSHA Data.

    Science.gov (United States)

    Lee, Derrick G; Lavoué, Jérôme; Spinelli, John J; Burstyn, Igor

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a group of pollutants with multiple variants classified as carcinogenic. The Occupational Safety and Health Administration (OSHA) provided access to two PAH exposure databanks of United States workplace compliance testing data collected between 1979 and 2010. Mixed-effects logistic models were used to predict the exceedance fraction (EF), i.e., the probability of exceeding OSHA's Permissible Exposure Limit (PEL = 0.2 mg/m3) for PAHs based on industry and occupation. Measurements of coal tar pitch volatiles were used as a surrogate for PAHs. Time, databank, occupation, and industry were included as fixed-effects while an identifier for the compliance inspection number was included as a random effect. Analyses involved 2,509 full-shift personal measurements. Results showed that the majority of industries had an estimated EF < 0.5, although several industries, including Standardized Industry Classification codes 1623 (Water, Sewer, Pipeline, and Communication and Powerline Construction), 1711 (Plumbing, Heating, and Air-Conditioning), 2824 (Manmade Organic Fibres), 3496 (Misc. Fabricated Wire products), and 5812 (Eating Places), and Major group's 13 (Oil and Gas Extraction) and 30 (Rubber and Miscellaneous Plastic Products), were estimated to have more than an 80% likelihood of exceeding the PEL. There was an inverse temporal trend of exceeding the PEL, with lower risk in most recent years, albeit not statistically significant. Similar results were shown when incorporating occupation, but varied depending on the occupation as the majority of industries predicted at the administrative level, e.g., managers, had an estimated EF < 0.5 while at the minimally skilled/laborer level there was a substantial increase in the estimated EF. These statistical models allow the prediction of PAH exposure risk through individual occupational histories and will be used to create a job-exposure matrix for use in a population-based case

  12. A General Simulation Framework for Supply Chain Modeling: State of the Art and Case Study

    OpenAIRE

    2010-01-01

    Nowadays there is a large availability of discrete event simulation software that can be easily used in different domains: from industry to supply chain, from healthcare to business management, from training to complex systems design. Simulation engines of commercial discrete event simulation software use specific rules and logics for simulation time and events management. Difficulties and limitations come up when commercial discrete event simulation software are used for modeling complex rea...

  13. Supply Chain Modeling: Downstream Risk Assessment Methodology (DRAM) Summary of Development and Application

    Science.gov (United States)

    2015-04-01

    Stockpile Requirements,” for the Strategic Materials Office of the Defense Logistics Agency (DLA). The views, opinions, and findings should not be... Logistics Agency Strategic Materials (DLA SM) to provide the capability to analyze supply chains of strategic and critical materials and the... material feedstock requirements. The fundamental approach is mass flow analysis, from raw material through each step in production. The model must also

  14. The project finance model in the supply of residential and commercial premises

    Directory of Open Access Journals (Sweden)

    Damir Juričić

    2010-06-01

    Full Text Available A supply of dwellings greater than the demand, a reduction in the availability of housing loans and increased credit risk, caused, inter alia, by the financial crisis: these are the basic features of today’s residential property and commercial premises markets in Croatia today. Built but unsold housing units have exposed private investors, who have organised the supply of units within the balance sheet of their firms, to significant risk of underinvestment. The materialisation of this risk is most manifested in the impossibility of funding the core business because of loans that they have agreed on for the construction of dwelling units meant for sale on the market. The paper then proposes a model that, if it were applied, could insure investors to a greater extent against the risk of underinvestment. The supply of dwelling units with protected rentals by the local public sector organised in the traditional manner, i.e. according to a model in which the local public sector figures in the role of investor, distributes the burden of development costs onto the future generations as well. However, practice has shown that traditional models inequitably expose future generations to the risk of a reduction in the quality of this kind of public service. From this point of view the proposed model transfers to the future generation not only the costs but also the obligations to secure equal qualities of public service in such a way that the private investor long-term assumes the risk of the availability of public building.The problem in this kind of organisation of the supply of a public service is double taxation via VAT, changes in the law concerning which are accordingly proposed.

  15. SUPPLIES COSTS: AN EXPLORATORY STUDY WITH APPLICATION OF MEASUREMENT MODEL OF LOGISTICS COSTS

    OpenAIRE

    Ana Paula Ferreira Alves; José Vanderlei Silva Borba; Gilberto Tavares dos Santos; Artur Roberto Gibbon

    2013-01-01

    One of the main reasons for the difficulty in adopting an integrated method of calculation of logistics costs is still a lack of adequate information about costs. The management of the supply chain and identify its costs can provide information for their managers, with regard to decision making, generating competitive advantage. Some models of calculating logistics costs are proposed by Uelze (1974), Dias (1996), Goldratt (2002), Christopher (2007), Castiglioni (2009) and Borba & Gibbon (2009...

  16. Evaluating Supply Chain Management: A Methodology Based on a Theoretical Model

    OpenAIRE

    Alexandre Tadeu Simon; Luiz Carlos Di Serio; Silvio Roberto Ignacio Pires; Guilherme Silveira Martins

    2015-01-01

    Despite the increasing interest in supply chain management (SCM) by researchers and practitioners, there is still a lack of academic literature concerning topics such as methodologies to guide and support SCM evaluation. Most developed methodologies have been provided by consulting companies and are restricted in their publication and use. This article presents a methodology for evaluating companies’ degree of adherence to a SCM conceptual model. The methodology is based on Cooper, Lambert an...

  17. A conservative vapour intrusion screening model of oxygen-limited hydrocarbon vapour biodegradation accounting for building footprint size

    Science.gov (United States)

    Knight, John H.; Davis, Gregory B.

    2013-12-01

    Petroleum hydrocarbon vapours pose a reduced risk to indoor air due to biodegradation processes where oxygen is available in the subsurface or below built structures. However, no previous assessment has been available to show the effects of a building footprint (slab size) on oxygen-limited hydrocarbon vapour biodegradation and the potential for oxygen to be present beneath the entire sub-slab region of a building. Here we provide a new, conservative and conceptually simple vapour screening model which links oxygen and hydrocarbon vapour transport and biodegradation in the vicinity and beneath an impervious slab. This defines when vapour risk is insignificant, or conversely when there is potential for vapour to contact the sub-slab of a building. The solution involves complex mathematics to determine the position of an unknown boundary interface between oxygen diffusing in from the ground surface and vapours diffusing upwards from a subsurface vapour source, but the mathematics reduces to a simple relationship between the vapour source concentration and the ratio of the half slab width and depth to the vapour source. Data from known field investigations are shown to be consistent with the model predictions. Examples of 'acceptable' slab sizes for vapour source depths and strengths are given. The predictions are conservative as an estimator of when petroleum hydrocarbon vapours might come in contact with a slab-on-ground building since additional sources of oxygen due to advective flow or diffusion through the slab are ignored. As such the model can be used for screening sites for further investigation.

  18. Informed Principal Model and Contract in Supply Chain with Demand Disruption Asymmetric Information

    Directory of Open Access Journals (Sweden)

    Huan Zhang

    2016-01-01

    Full Text Available Because of the frequency and disastrous influence, the supply chain disruption has caused extensive concern both in the industry and in the academia. In a supply chain with one manufacturer and one retailer, the demand of the retailer is uncertain and meanwhile may suffer disruption with a probability. Taking the demand disruption probability as the retailer’s asymmetric information, an informed principal model with the retailer as the principal is explored to make the contract. The retailer can show its information to the manufacturer through the contract. It is found out that the high-risk retailer intends to pretend to be the low-risk one. So the separating contract is given through the low-information-intensity allocation, in which the order quantity and the transferring payment for the low-risk retailer distort upwards, but those of high-risk retailer do not distort. In order to reduce the signaling cost which the low-risk retailer pays, the interim efficient model is introduced, which ends up with the order quantity and transferring payment distorting upwards again but less than before. In the numerical examples, with two different mutation probabilities, the informed principal contracts show the application of the informed principal model in the supply chain with demand disruption.

  19. Models for Analyzing the Driving Force of Cultivated Land Supply Change

    Institute of Scientific and Technical Information of China (English)

    LIU Yanfang; ZHANG Yuqian; XIAO Bin

    2004-01-01

    This paper focuses on a series of quantitative analysis models, such as grey relational analysis model, hierarchical cluster analysis model, principal component analysis model, linear regression model and elastic coefficient model. These models are used to analyze the comprehensive function and effect of driving forces systemically, including analysis on features, analysis for differentiating the primary and the secondary, analysis on comprehensive effects, analysis of elasticity, analysis of prediction. The primary and characteristic factors can be extracted by analysis of features and analysis for differentiating the primary and the secondary. Analysis on prediction and elasticity can predict the area of cultivated land in the future and find out which factors exert great influence on the cultivated land supply.

  20. Quantitative structure-activity relationship modeling of polycyclic aromatic hydrocarbon mutagenicity by classification methods based on holistic theoretical molecular descriptors.

    Science.gov (United States)

    Gramatica, Paola; Papa, Ester; Marrocchi, Assunta; Minuti, Lucio; Taticchi, Aldo

    2007-03-01

    Various polycyclic aromatic hydrocarbons (PAHs), ubiquitous environmental pollutants, are recognized mutagens and carcinogens. A homogeneous set of mutagenicity data (TA98 and TA100,+S9) for 32 benzocyclopentaphenanthrenes/chrysenes was modeled by the quantitative structure-activity relationship classification methods k-nearest neighbor and classification and regression tree, using theoretical holistic molecular descriptors. Genetic algorithm provided the selection of the best subset of variables for modeling mutagenicity. The models were validated by leave-one-out and leave-50%-out approaches and have good performance, with sensitivity and specificity ranges of 90-100%. Mutagenicity assessment for these PAHs requires only a few theoretical descriptors of their molecular structure.

  1. A simple metabolic model of glacial-interglacial energy supply to the upper ocean

    Directory of Open Access Journals (Sweden)

    J. L. Pelegrí

    2011-03-01

    Full Text Available We use a simple two-state two-box ocean to simulate the CO2 signal during the last four glacial-interglacial transitions in the earth system. The model is inspired by the similarity in spatial organization and temporal transition patterns between the earth and other complex systems, such as mammals. The comparison identifies the earth's metabolic rate with net autotrophic primary production in the upper ocean, sustained through new inorganic carbon and nutrients advected from the deep ocean and organic matter remineralized within the upper ocean. We view the glacial-interglacial transition as a switch of the upper ocean from a basal to an enhanced metabolic state, with energy supply initially relying on the remineralization of the local organic sources and the eventual steady state resulting from the increased advective supply of inorganic deep sources. During the interglacial-glacial transition the opposite occurs, with an initial excess of advective supply and primary production that allows the replenishment of the upper-ocean organic storages. We set the relative change in energy supply from the CO2 signal and use genetic algorithms to explore the sensitivity of the model output to both the basal recirculation rate and the intensity-timing of the maximum recirculation rate. The model is capable of reproducing quite well the long-term oscillations, as shown by correlations with observations typically about 0.8. The dominant time scale for each cycle ranges between about 40 and 45 kyr, close to the 41 kyr average obliquity astronomical period, and the deep-ocean recirculation rate increases between one and two orders of magnitude from glacial to interglacial periods.

  2. A generic conceptual and UML model for the multi-echelon distribution supply chain

    Directory of Open Access Journals (Sweden)

    Hamid Ech-Cheikh

    2012-10-01

    Full Text Available The Multi-Echelon Distribution Supply Chain (MEDSC is a multifaceted structure, focusing on the integration of all factors that involved in the overall distribution process of finished products to thecustomers. The growing interest in multi-echelon distribution systems has highlighted the need to adopt an appropriate approach to ensure the efficient management of their complexity. While there is asignificant amount of analytical research modeling the MEDSC, few studies have used simulation models for this system. The objective of the paper is to model the operational level of the MEDSC network and to obtain a real reflection of its behavior. The permanent interaction among the various components of the MEDSC and the increasing complexity of such system requires a simulation model, which is able to integrate a set of dynamic characteristics and stochastic aspects. Furthermore, this model will be adapted to several configurations of the multi-echelon network. Thus, this research has twofold: first to recall the issues regarding the flow management and inventory control in the MEDSC, then using the objectoriented approach through the Unified Modeling Language (UML to build a flexible supply chain model.

  3. Evaluation of Supply Chain Efficiency Based on a Novel Network of Data Envelopment Analysis Model

    Science.gov (United States)

    Fu, Li Fang; Meng, Jun; Liu, Ying

    2015-12-01

    Performance evaluation of supply chain (SC) is a vital topic in SC management and inherently complex problems with multilayered internal linkages and activities of multiple entities. Recently, various Network Data Envelopment Analysis (NDEA) models, which opened the “black box” of conventional DEA, were developed and applied to evaluate the complex SC with a multilayer network structure. However, most of them are input or output oriented models which cannot take into consideration the nonproportional changes of inputs and outputs simultaneously. This paper extends the Slack-based measure (SBM) model to a nonradial, nonoriented network model named as U-NSBM with the presence of undesirable outputs in the SC. A numerical example is presented to demonstrate the applicability of the model in quantifying the efficiency and ranking the supply chain performance. By comparing with the CCR and U-SBM models, it is shown that the proposed model has higher distinguishing ability and gives feasible solution in the presence of undesirable outputs. Meanwhile, it provides more insights for decision makers about the source of inefficiency as well as the guidance to improve the SC performance.

  4. Variations on a theme - the evolution of hydrocarbon solids: I. Compositional and spectral modelling - the eRCN and DG models

    CERN Document Server

    Jones, A P

    2015-01-01

    Context. The compositional properties of hydrogenated amorphous carbons are known to evolve in response to the local conditions. Aims. To present a model for low-temperature, amorphous hydrocarbon solids, based on the microphysical properties of random and defected networks of carbon and hydrogen atoms, that can be used to study and predict the evolution of their properties in the interstellar medium. Methods. We adopt an adaptable and prescriptive approach to model these materials, which is based on a random covalent network (RCN) model, extended here to a full compositional derivation (the eRCN model), and a defective graphite (DG) model for the hydrogen poorer materials where the eRCN model is no longer valid. Results. We provide simple expressions that enable the determination of the structural, infrared and spectral properties of amorphous hydrocarbon grains as a function of the hydrogen atomic fraction, XH. Structural annealing, resulting from hydrogen atom loss, results in a transition from H-rich, ali...

  5. Photocatalytic degradation of oil industry hydrocarbons models at laboratory and at pilot-plant scale

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Ronald; Nunez, Oswaldo [Laboratorio de Fisicoquimica Organica y Quimica Ambiental, Departamento de Procesos y Sistemas, Universidad Simon Bolivar, Apartado Postal 89000, Caracas (Venezuela)

    2010-02-15

    Photodegradation/mineralization (TiO{sub 2}/UV Light) of the hydrocarbons: p-nitrophenol (PNP), naphthalene (NP) and dibenzothiophene (DBT) at three different reactors: batch bench reactor (BBR), tubular bench reactor (TBR) and tubular pilot-plant (TPP) were kinetically monitored at pH = 3, 6 and 10, and the results compared using normalized UV light exposition times. The results fit the Langmuir-Hinshelwood (LH) model; therefore, LH adsorption equilibrium constants (K) and apparent rate constants (k) are reported as well as the apparent pseudo-first-order rate constants, k{sub obs}{sup '} = kK/(1 + Kc{sub r}). The batch bench reactor is the most selective reactor toward compound and pH changes in which the reactivity order is: NP > DBT > PNP, however, the catalyst adsorption (K) order is: DBT > NP > PNP at the three pH used but NP has the highest k values. The tubular pilot-plant (TPP) is the most efficient of the three reactors tested. Compound and pH photodegradation/mineralization selectivity is partially lost at the pilot plant where DBT and NP reaches ca. 90% mineralization at the pH used, meanwhile, PNP reaches only 40%. The real time, in which these mineralization occur are: 180 min for PNP and 60 min for NP and DBT. The mineralization results at the TPP indicate that for the three compounds, the rate limiting step is the same as the degradation one. So that, there is not any stable intermediate that may accumulate during the photocatalytic treatment. (author)

  6. A subjective supply-demand model: the maximum Boltzmann/Shannon entropy solution

    Science.gov (United States)

    Piotrowski, Edward W.; Sładkowski, Jan

    2009-03-01

    The present authors have put forward a projective geometry model of rational trading. The expected (mean) value of the time that is necessary to strike a deal and the profit strongly depend on the strategies adopted. A frequent trader often prefers maximal profit intensity to the maximization of profit resulting from a separate transaction because the gross profit/income is the adopted/recommended benchmark. To investigate activities that have different periods of duration we define, following the queuing theory, the profit intensity as a measure of this economic category. The profit intensity in repeated trading has a unique property of attaining its maximum at a fixed point regardless of the shape of demand curves for a wide class of probability distributions of random reverse transactions (i.e. closing of the position). These conclusions remain valid for an analogous model based on supply analysis. This type of market game is often considered in research aiming at finding an algorithm that maximizes profit of a trader who negotiates prices with the Rest of the World (a collective opponent), possessing a definite and objective supply profile. Such idealization neglects the sometimes important influence of an individual trader on the demand/supply profile of the Rest of the World and in extreme cases questions the very idea of demand/supply profile. Therefore we put forward a trading model in which the demand/supply profile of the Rest of the World induces the (rational) trader to (subjectively) presume that he/she lacks (almost) all knowledge concerning the market but his/her average frequency of trade. This point of view introduces maximum entropy principles into the model and broadens the range of economic phenomena that can be perceived as a sort of thermodynamical system. As a consequence, the profit intensity has a fixed point with an astonishing connection with Fibonacci classical works and looking for the quickest algorithm for obtaining the extremum of a

  7. SCRL-Model for Human Space Flight Operations Enterprise Supply Chain

    Science.gov (United States)

    Tucker, Brian

    2010-01-01

    Standard approach to evaluate and configure adaptable and sustainable program and mission supply chains at an enterprise level. End-to-end view. Total Lifecycle. Evaluate the readiness of the supply chain during the supply chain development phase.

  8. Development of a global electricity supply model and investigation of electricity supply by renewable energies with a focus on energy storage requirements for Europe

    Energy Technology Data Exchange (ETDEWEB)

    Troendle, Tobias Wolfgang

    2014-12-12

    Electricity supply at present requires about 38% of the global primary energy demand and it is likely to rise further in the coming decades. Facing major problems, such as limited resources of fuels and an ongoing anthropogenic climate change, a sustainable electricity supply based on renewable energies is absolutely vital. Wind and solar power will play an extensive role in future supplies but require energy storage capacities to meet electricity demand. To investigate the relationship of power plant mix and required energy storage capacity, a computer model based on global weather data has been developed to enable the simulation of electricity supply scenarios by up to ten different power plant types for various regions. The focus of the investigation has been on the energy storage requirements of an electricity supply for Europe by wind and solar power. The minimum required energy storage capacity for a totally weather dependent electricity supply occurs at a ratio of 30% wind and 70% photovoltaic (PV) power plant capacity installed. Thus, the required energy storage capacity rises from a transition of to-day's electricity supply to the afore-mentioned 100% renewable wind and PV scenario exponentially to about 150 TWh (3.8% of the annual electricity demand). The installation of additional excess wind and PV power plant capacity was seen to be an efficient way to reduce the required energy storage. Already 10% excess capacity lead to a reduction by 50% of the required storage capacity. To use different storage technologies in an optimised way in terms of storage capacity and efficiency, the storage tasks can be separated into a daily and a seasonal usage. While the seasonal storage capacity has to be about two orders of magnitude larger than the required capacity of the storage for the daily cycle, the sum of stored energy during one year is almost equal for the long and short time storage. In summary, an electricity supply by wind and PV power was shown to

  9. The use of "Echo model" in the design of data communication system on power supply networks

    Directory of Open Access Journals (Sweden)

    S. V. Onopa

    2014-04-01

    Full Text Available Introduction. Analysis of power supply network and research parameters for possible use as an environment of data transfer which are considered in the broadband frequency range. The purpose of this work is the usage of "echo model" in research of features of electric grid. Description of the modeling. To study the proposed model is necessary to research the parameters of the electric grid: capacitance, inductance, conductance and conductor resistance, which are the initial data for modeling. Consideration of the grid as multipath channel includes: a reflection signal which is present because of uncoordinated resistance and causes attenuation and signal delay. The transfer function of model considers to all listed above effects. Conclusions. Modeling results, which are the graphical representation of the channel characteristics for copper and aluminum wires. Recommendations for the use of PLC technology the presences of spectral characteristic bay in which data transfer with errors.

  10. A model of Supply chain resilience for competitiveness in Iranian automotive companies

    Directory of Open Access Journals (Sweden)

    amir mohammad fakoor sagihe

    2014-05-01

    Full Text Available Dynamic nature of global business makes it necessary for supply chains to be adaptable to changes. Also, complexities of the working environment and increasing competition in different industries have led to unstableness of the competitiveness factors. Creating and maintaining competitiveness need capabilities which create value for costumers based on the organization capacities. In the present study, a model of supply chain resilience is presented for competitiveness in Iranian automotive companies. It is expected that by its application, automobile firms not only have an effective method for controlling incidents, but also get to competitiveness. For this purpose, first by extensive review of the literature, a preliminary conceptual framework was extracted for supply chain resilience in order to create competitiveness. Then, using experts' views (Delphi method, interview, and doing the survey, the research model was formed and finalized based on the conditions of Iranian automobile industry. Results of the study showed that Iranian automobile firms can create the required flexibility for encountering the most important vulnerabilities of the firms by creating or improving capabilities like flexibility in sourcing, efficiency, security, flexibility in fulfillment, adaptability, and collaboration, and then using these opportunities they create competitiveness. The vulnerabilities of the firms include things like exchange and price fluctuations, international sanctions, weakness in know-how, low quality of the products, and weak services.

  11. MOSES – A modelling tool for the analysis of scenarios of the European electricity supply system

    Directory of Open Access Journals (Sweden)

    Agert C.

    2012-10-01

    Full Text Available Recent studies have shown that a transition of the current power supply system in Europe to a system almost entirely based on fluctuating Renewable Energy Sources (RES by mid-century is possible. However, most of these scenarios require a significant amount of back-up power capacities to ensure the security of electricity supply. This would imply high additional investments and operating costs. Hence, alternative options should be investigated first. Here we present a first outlook of our simulation model MOSES which will be able to analyse different target states of the European electricity system in 2050. In this model long-term meteorological data series are used to optimise the capacity mix of RES in Europe. One of the main elements of our tool is a simplified electricity network. In addition, alternative options for reduction of additional back-up power like the expansion of the transmission grid, the use of demand-side management and/or the installation of over-capacities will be implemented. The results will be used to provide scientifically proven recommendations to policy makers for a reliable energy supply system in Europe based on Renewable Energy Sources.

  12. Investigation of Effectiveness of Order Review and Release Models in Make to Order Supply Chain

    Directory of Open Access Journals (Sweden)

    Kundu Kaustav

    2016-01-01

    Full Text Available Nowadays customisation becomes more common due to vast requirement from the customers for which industries are trying to use make-to-order (MTO strategy. Due to high variation in the process, workload control models are extensively used for jobshop companies which usually adapt MTO strategy. Some authors tried to implement workload control models, order review and release systems, in non-repetitive manufacturing companies, where there is a dominant flow in production. Those models are better in shop floor but their performances are never been investigated in high variation situations like MTO supply chain. This paper starts with the introduction of particular issues in MTO companies and a general overview of order review and release systems widely used in the industries. Two order review and release systems, the Limited and Balanced models, particularly suitable for flow shop system are applied to MTO supply chain, where the processing times are difficult to estimate due to high variation. Simulation results show that the Balanced model performs much better than the Limited model if the processing times can be estimated preciously.

  13. Analysing green supply chain management practices in Brazil's electrical/electronics industry using interpretive structural modelling

    DEFF Research Database (Denmark)

    Govindan, Kannan; Kannan, Devika; Mathiyazhagan, K.

    2013-01-01

    Industries need to adopt the environmental management concepts in the traditional supply chain management. The green supply chain management (GSCM) is an established concept to ensure environment-friendly activities in industry. This paper identifies the relationship of driving and dependence...... that exists between GSCM practices with regard to their adoption within Brazilian electrical/electronic industry with the help of interpretive structural modelling (ISM). From the results, we infer that cooperation with customers for eco-design practice is driving other practices, and this practice acts...... as a vital role among other practices. Commitment to GSCM from senior managers and cooperation with customers for cleaner production occupy the highest level. © 2013 © 2013 Taylor & Francis....

  14. Warehousing in the Global Supply Chain Advanced Models, Tools and Applications for Storage Systems

    CERN Document Server

    2012-01-01

    With increased globalization and offshore sourcing, global supply chain management is becoming an important issue for many businesses as it involves a company's worldwide interests and suppliers rather than simply a local or national orientation. The storage systems significantly affect the level of quality of products, the customer’s service level, and the global logistic cost. The mission of warehousing systems design, control and optimization is to effectively ship products in the right place, at the right time, and in the right quantity (i.e. in any configuration) without any damages or alterations, and minimizing costs. Warehousing in the Global Supply Chain presents and discusses a set of models, tools and real applications, including a few case studies rarely presented with a sufficient detail by other literature, to illustrate the main challenges in warehousing activities. This includes all warehouse operations (from receiving to shipping), problems and issues (e.g. storage allocation, assignment,...

  15. Performance Measurement of Water Desalination Supply Chain Using Balanced Scorecard Model

    Directory of Open Access Journals (Sweden)

    Hasan Balfaqih

    2016-02-01

    Full Text Available The purpose of this study is to propose a theoretical framework based on a balanced scorecard (BSC for performance measurement in the water desalination supply chain (WDSC. The reason for choosing this context is that the supply chain (SC of water desalination has received a great amount of attention, due to issues related to the increased need of fresh water for agricultural, industrial and human consumptions. The research methodology is based on literature analysis concerning performance measurement and metrics, the water desalination industry and the BSC model. Different SC performance measures which related to WDSC have been reviewed and distributed into four BSC perspectives: financial, customer, internal business, and learning & growth. The article provides a structured theoretical framework specific for WDSC. This is the first developed framework in WDSC which could serve as a reference to develop applicable performance indicators, and it is expected that both researchers and practitioners would benefit from the proposed framework.

  16. A Multiobjective Optimization Model of Production-Sourcing for Sustainable Supply Chain with Consideration of Social, Environmental, and Economic Factors

    Directory of Open Access Journals (Sweden)

    Zhixiang Chen

    2014-01-01

    Full Text Available This paper incorporates the three pillars of sustainability—economic, environmental, and social dimensions—into a supply chain. A multiobjective programming model which jointly minimizes costs, emissions, and employee injuries in a supply chain is first constructed. Using the weighted-sum approach with weights setting by the analytic hierarchy process (AHP, the model is solved by normalization of the minima of the three objectives. A numerical example is conducted to test the model. The results show that it is indeed possible to integrate environmental and social metrics in supply chain system optimization. Multiobjective optimization can balance the social, environmental, and economic performance. This paper presents a new multidimension perspective for optimizing supply chain; it will inspire practitioners to change their decision ideas and improve supply chain sustainability.

  17. A new strategy of glucose supply in a microbial fermentation model

    Science.gov (United States)

    Kasbawati, Gunawan, A. Y.; Sidarto, K. A.; Hertadi, R.

    2015-09-01

    Strategy of glucose supply to achieve an optimal productivity of ethanol production of a yeast cell is one of the main features in a microbial fermentation process. Beside a known continuous glucose supply, in this study we consider a new supply strategy so called the on-off supply. An optimal control theory is applied to the fermentation system to find the optimal rate of glucose supply and time of supply. The optimization problem is solved numerically using Differential Evolutionary algorithm. We find two alternative solutions that we can choose to get the similar result: either long period process with low supply or short period process with high glucose supply.

  18. Process modeling and supply chain design for advanced biofuel production based on bio-oil gasification

    Science.gov (United States)

    Li, Qi

    As a potential substitute for petroleum-based fuel, second generation biofuels are playing an increasingly important role due to their economic, environmental, and social benefits. With the rapid development of biofuel industry, there has been an increasing literature on the techno-economic analysis and supply chain design for biofuel production based on a variety of production pathways. A recently proposed production pathway of advanced biofuel is to convert biomass to bio-oil at widely distributed small-scale fast pyrolysis plants, then gasify the bio-oil to syngas and upgrade the syngas to transportation fuels in centralized biorefinery. This thesis aims to investigate two types of assessments on this bio-oil gasification pathway: techno-economic analysis based on process modeling and literature data; supply chain design with a focus on optimal decisions for number of facilities to build, facility capacities and logistic decisions considering uncertainties. A detailed process modeling with corn stover as feedstock and liquid fuels as the final products is presented. Techno-economic analysis of the bio-oil gasification pathway is also discussed to assess the economic feasibility. Some preliminary results show a capital investment of 438 million dollar and minimum fuel selling price (MSP) of $5.6 per gallon of gasoline equivalent. The sensitivity analysis finds that MSP is most sensitive to internal rate of return (IRR), biomass feedstock cost, and fixed capital cost. A two-stage stochastic programming is formulated to solve the supply chain design problem considering uncertainties in biomass availability, technology advancement, and biofuel price. The first-stage makes the capital investment decisions including the locations and capacities of the decentralized fast pyrolysis plants and the centralized biorefinery while the second-stage determines the biomass and biofuel flows. The numerical results and case study illustrate that considering uncertainties can be

  19. An approach for modeling sediment budgets in supply-limited rivers

    Science.gov (United States)

    Wright, Scott A.; Topping, David J.; Rubin, David M.; Melis, Theodore S.

    2010-01-01

    Reliable predictions of sediment transport and river morphology in response to variations in natural and human-induced drivers are necessary for river engineering and management. Because engineering and management applications may span a wide range of space and time scales, a broad spectrum of modeling approaches has been developed, ranging from suspended-sediment "rating curves" to complex three-dimensional morphodynamic models. Suspended sediment rating curves are an attractive approach for evaluating changes in multi-year sediment budgets resulting from changes in flow regimes because they are simple to implement, computationally efficient, and the empirical parameters can be estimated from quantities that are commonly measured in the field (i.e., suspended sediment concentration and water discharge). However, the standard rating curve approach assumes a unique suspended sediment concentration for a given water discharge. This assumption is not valid in rivers where sediment supply varies enough to cause changes in particle size or changes in areal coverage of sediment on the bed; both of these changes cause variations in suspended sediment concentration for a given water discharge. More complex numerical models of hydraulics and morphodynamics have been developed to address such physical changes of the bed. This additional complexity comes at a cost in terms of computations as well as the type and amount of data required for model setup, calibration, and testing. Moreover, application of the resulting sediment-transport models may require observations of bed-sediment boundary conditions that require extensive (and expensive) observations or, alternatively, require the use of an additional model (subject to its own errors) merely to predict the bed-sediment boundary conditions for use by the transport model. In this paper we present a hybrid approach that combines aspects of the rating curve method and the more complex morphodynamic models. Our primary objective

  20. An approach for modeling sediment budgets in supply-limited rivers

    Science.gov (United States)

    Wright, Scott A.; Topping, David J.; Rubin, David M.; Melis, Theodore S.

    2010-10-01

    Reliable predictions of sediment transport and river morphology in response to variations in natural and human-induced drivers are necessary for river engineering and management. Because engineering and management applications may span a wide range of space and time scales, a broad spectrum of modeling approaches has been developed, ranging from suspended-sediment "rating curves" to complex three-dimensional morphodynamic models. Suspended sediment rating curves are an attractive approach for evaluating changes in multi-year sediment budgets resulting from changes in flow regimes because they are simple to implement, computationally efficient, and the empirical parameters can be estimated from quantities that are commonly measured in the field (i.e., suspended sediment concentration and water discharge). However, the standard rating curve approach assumes a unique suspended sediment concentration for a given water discharge. This assumption is not valid in rivers where sediment supply varies enough to cause changes in particle size or changes in areal coverage of sediment on the bed; both of these changes cause variations in suspended sediment concentration for a given water discharge. More complex numerical models of hydraulics and morphodynamics have been developed to address such physical changes of the bed. This additional complexity comes at a cost in terms of computations as well as the type and amount of data required for model setup, calibration, and testing. Moreover, application of the resulting sediment-transport models may require observations of bed-sediment boundary conditions that require extensive (and expensive) observations or, alternatively, require the use of an additional model (subject to its own errors) merely to predict the bed-sediment boundary conditions for use by the transport model. In this paper we present a hybrid approach that combines aspects of the rating curve method and the more complex morphodynamic models. Our primary objective

  1. Part I: C2sbnd C4 hydrocarbons separation addressed via molecular cluster models carved out from periodic MOF-74-Mg/Zn structures

    Science.gov (United States)

    Degaga, Gemechis D.; Valenzano, Loredana

    2016-09-01

    Selective sorption of hydrocarbons by tunable sorbents such as metal-organic frameworks is the most promising alternative to traditional cryogenic distillation. Here, density functional theory is used to investigate the selective sorption of C2sbnd C4 hydrocarbons by MOF-74-Mg/Zn via periodic and molecular cluster calculations. Both methods agree in showing significant differences in binding energies between olefins and paraffins at the open metal sites of the MOF. The binding energies found using molecular cluster models, however, are significantly smaller than those obtained from the periodic approach, exemplifying the importance of fully accounting for the chemical environment experienced by the adsorbed hydrocarbons.

  2. Reduced combustion mechanism for C1-C4 hydrocarbons and its application in computational fluid dynamics flare modeling.

    Science.gov (United States)

    Damodara, Vijaya; Chen, Daniel H; Lou, Helen H; Rasel, Kader M A; Richmond, Peyton; Wang, Anan; Li, Xianchang

    2017-05-01

    Emissions from flares constitute unburned hydrocarbons, carbon monoxide (CO), soot, and other partially burned and altered hydrocarbons along with carbon dioxide (CO2) and water. Soot or visible smoke is of particular concern for flare operators/regulatory agencies. The goal of the study is to develop a computational fluid dynamics (CFD) model capable of predicting flare combustion efficiency (CE) and soot emission. Since detailed combustion mechanisms are too complicated for (CFD) application, a 50-species reduced mechanism, LU 3.0.1, was developed. LU 3.0.1 is capable of handling C4 hydrocarbons and soot precursor species (C2H2, C2H4, C6H6). The new reduced mechanism LU 3.0.1 was first validated against experimental performance indicators: laminar flame speed, adiabatic flame temperature, and ignition delay. Further, CFD simulations using LU 3.0.1 were run to predict soot emission and CE of air-assisted flare tests conducted in 2010 in Tulsa, Oklahoma, using ANSYS Fluent software. Results of non-premixed probability density function (PDF) model and eddy dissipation concept (EDC) model are discussed. It is also noteworthy that when used in conjunction with the EDC turbulence-chemistry model, LU 3.0.1 can reasonably predict volatile organic compound (VOC) emissions as well. A reduced combustion mechanism containing 50 C1-C4 species and soot precursors has been developed and validated against experimental data. The combustion mechanism is then employed in the computational fluid dynamics (CFD) of modeling of soot emission and combustion efficiency (CE) of controlled flares for which experimental soot and CE data are available. The validated CFD modeling tools are useful for oil, gas, and chemical industries to comply with U.S. Environmental Protection Agency's (EPA) mandate to achieve smokeless flaring with a high CE.

  3. Theoretical modeling of infrared emission from neutral and charged polycyclic aromatic hydrocarbons. II.

    NARCIS (Netherlands)

    Bakes, ELO; Tielens, AGGM; Bauschlicher, CW; Hudgins, DM; Allamandola, LJ

    2001-01-01

    The nature of the carriers of the interstellar infrared (IR) emission features between 3.3 and 12.7 mum is complex. We must consider emission from a family of polycyclic aromatic hydrocarbons (PAHs) in a multiplicity of cationic charge states (+1, +2, +3, and so on), along with neutral and anionic P

  4. Business Process Modelling Languages in Designing Integrated Information System for Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Mohsen Mohammadi

    2012-01-01

    Full Text Available A business process model is very germane to the formation of an appropriate information system. For a marked infusion of business processes in the supply chain, the status quo regarding the processes must be totally understood and well secured. Business activities and sequence have to be well kept and properly coordinated by predicting business procedures process from diverse views. This study examines seven BPMLs Data Flow Diagram (DFD, Unified Modelling Language (UML, Business Process Modelling Notation(BPMN, Event Driven Process Chain (EPC, IDEF, Petri Net, and Role Activity Diagram (RAD. The submissions of this study are the subject of the Business Process Modelling Languages (BPMLs in developing an integrated dissemination mechanism and classification of modelling tools.

  5. Comparing risk of failure models in water supply networks using ROC curves

    Energy Technology Data Exchange (ETDEWEB)

    Debon, A., E-mail: andeau@eio.upv.e [Centro de Gestion de la Calidad y del Cambio, Dpt. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Carrion, A. [Centro de Gestion de la Calidad y del Cambio, Dpt. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Cabrera, E. [Dpto. De Ingenieria Hidraulica Y Medio Ambiente, Instituto Tecnologico del Agua, Universidad Politecnica de Valencia, E-46022 Valencia (Spain); Solano, H. [Universidad Diego Portales, Santiago (Chile)

    2010-01-15

    The problem of predicting the failure of water mains has been considered from different perspectives and using several methodologies in engineering literature. Nowadays, it is important to be able to accurately calculate the failure probabilities of pipes over time, since water company profits and service quality for citizens depend on pipe survival; forecasting pipe failures could have important economic and social implications. Quantitative tools (such as managerial or statistical indicators and reliable databases) are required in order to assess the current and future state of networks. Companies managing these networks are trying to establish models for evaluating the risk of failure in order to develop a proactive approach to the renewal process, instead of using traditional reactive pipe substitution schemes. The main objective of this paper is to compare models for evaluating the risk of failure in water supply networks. Using real data from a water supply company, this study has identified which network characteristics affect the risk of failure and which models better fit data to predict service breakdown. The comparison using the receiver operating characteristics (ROC) graph leads us to the conclusion that the best model is a generalized linear model. Also, we propose a procedure that can be applied to a pipe failure database, allowing the most appropriate decision rule to be chosen.

  6. The power supply system model of the process submersible device with AC power transmission over the cable-rope

    Science.gov (United States)

    Rulevskiy, V. M.; Bukreev, V. G.; Kuleshova, E. O.; Shandarova, E. B.; Shandarov, S. M.; Vasilyeva, Yu Z.

    2017-02-01

    A practical problem of power supply system modeling for the process submersible device with AC power transmission over the cable-rope was considered. The problem is highly relevant in developing and operation of submersible centrifugal pumps and submersibles. The results of modeling a symmetrical three-phase power supply system and their compliance with the real data are given at the paper. The obtained results in the mathematical and simulation models were similar.

  7. Modelling high-resolution snow cover precipitation supply for German river catchments with SNOW 4

    Science.gov (United States)

    Böhm, Uwe; Reich, Thomas; Schneider, Gerold; Fiedler, Anett

    2013-04-01

    Formation of snow cover causes a delayed response of surface to precipitation. Both melting of snow and release of liquid water retained within the snow cover form precipitation supply which contributes to runoff and infiltration. The model SNOW 4 is developed to simulate snow cover accumulation and depletion and the resulting precipitation supply on a regular grid. The core of the model is formed by a set of equations which describe the snow cover energy and mass balance. The snow surface energy balance is calculated as a result of the radiation balance and the heat fluxes between atmosphere, soil and snow cover. The available melting heat enters the mass balance computation part of the model and melting of snow or freezing of liquid water within the snow layer takes place depending on its sign. Retention, aging and snow cover regeneration are taken into consideration. The model runs operationally 4 times a day and provides both a snow cover and precipitation supply analysis for the last 30 hours and a forecast for up to 72 hours. For the 30-hour analysis, regionalised observations are used both to define the initial state and force the model. Hourly measurements of air temperature, water vapour pressure, wind speed, global radiation or sunshine duration and precipitation are interpolated to the model grid. For the forecast period, SNOW 4 obtains the required input data from the operational products of the COSMO-EU weather forecast model. The size of a grid box is 1km2. The model area covers a region of 1100x1000km2 and includes the catchments of the German rivers completely. The internal time step is set to 1 hour. Once a day, the compliance between model and regionalized snow cover data is assessed. If discrepancies exceed certain thresholds, the model must be adjusted by a weighted approach towards the observations. The model simulations are updated every six hours based on the most recent observations and weather forecasts. The model works operationally since

  8. Contamination of water supplies by volcanic ashfall: A literature review and simple impact modelling

    Science.gov (United States)

    Stewart, C.; Johnston, D. M.; Leonard, G. S.; Horwell, C. J.; Thordarson, T.; Cronin, S. J.

    2006-11-01

    Volcanic ash is the most widely-distributed product of explosive volcanic eruptions, and can disrupt vital infrastructure on a large scale. Previous studies of effects of ashfall on natural waters and water supplies have focused mainly on the consequences of increased levels of turbidity (ash suspended in water), acidity and fluoride, with very little attention paid to other contaminants associated with volcanic ash. The aims of this paper are twofold: firstly, to review previous studies of the effects of volcanic ashfall on water supplies and identify information gaps; and secondly, to propose a simple model for predicting effects of ashfall on water supplies using available information on ash composition. We reviewed reported impacts of historic eruptions on water supplies, drawing on case studies from New Zealand, Vanuatu, Argentina, the USA, Costa Rica, Montserrat, Iceland and Guadeloupe. Elevated concentrations of fluoride, iron, sulphate and chloride, as well as turbidity and acidity, have been reported in water supplies. From a public health perspective, the two main issues appear to be: (1) outbreaks of infectious disease caused by the inhibition of disinfection by high levels of suspended ash, and (2) elevated fluoride concentrations. We devised a simple model using volcanic ash leachate composition data to predict effects on receiving waters. Applying this model to the effects of Ruapehu ash, from the 1995/1996 eruptions, suggests that the primary effects of concern are likely to be an increase in acidity (decrease in pH), and increases in concentrations of the metals aluminium, iron and manganese. These metals are not normally considered to pose health risks, and are regulated only by secondary, non-enforceable guidelines. However, exceedences of guideline values for Al, Mn, Fe and pH will cause water to become undrinkable due to a bitter metallic taste and dark colour, and may also cause corrosion, staining and scale deposition problems in water tanks

  9. Reactive transport modeling of CO2 injection in the Farnsworth, Texas hydrocarbon field

    Science.gov (United States)

    Ahmmed, B.; Appold, M. S.; McPherson, B. J. O. L.; Grigg, R.; White, M. D.

    2014-12-01

    The Farnsworth hydrocarbon field in northern Texas has been an experimental site for CO2 sequestration and enhanced oil recovery for the U.S. Department of Energy-sponsored Southwest Partnership (SWP) since April, 2013. CO2 is to be injected into the Pennsylvanian Morrow Sandstone at a rate of 200,000 tonnes per year for at least five years. The Morrow is a quartz-rich sandstone that lies at a depth of about 2400 m. Pore water in the Morrow has a total dissolved solids content of about 3600 mg/L dominated by Na, Cl, bicarbonate, and Ca. A reactive solute transport model was constructed for a 1700 × 1700 × 95 m volume using the TOUGHREACT software and the ECO2N equation of state for aqueous brine and CO2. Simulations were carried out to 100 years. The results showed immiscible CO2 gas to be concentrated in a lateral plume extending radially from the well screen, its ascent impeded by vigorous lateral groundwater flow in the more permeable upper Morrow. CO2 was much more widespread in aqueous solution, lowering pH throughout much of the model volume after 100 years, to a minimum of about 4.7. The low reactivity of the Morrow Sandstone due to its quartz-rich matrix and dilute pore fluid resulted in little mineral precipitation or dissolution, with net volume changes for any mineral no higher than order 10-4. The simulations predicted net dissolution of albite, calcite, and chlorite, and net precipitation of dawsonite, illite, and magnesite. The Morrow matrix was predicted to undergo slight net dissolution overall, resulting in porosity increases of up to 0.01%, suggesting that the Morrow would be resistant to significant changes in hydraulic properties as a result of the proposed amount of CO2 injection. For the 100 year simulation times calculated thus far, only a small fraction of the injected CO2 would be sequestered as carbonate minerals, with most of the injected CO2 dissolved in the aqueous phase.

  10. The Optimization Model of Earthquake Emergency Supplies Collecting with the Limited Period and Double-Level Multihub

    Directory of Open Access Journals (Sweden)

    Huang Xing

    2016-01-01

    Full Text Available This paper constructed a multiobjective programming model and designed Particle Swarm Optimization (PSO algorithm for earthquake emergency to solve the optimal decision-making question of Multihub emergency supplies collection network with constrained demand period and collection time as fuzzy interval numbers and capacity limit to hub nodes. As for algorithm design, a two-stage parallel solution mode was employed to achieve the global optimal solution in the solution space. At first, the paper is based on the constraint to the total time of emergency supplies collection system and the capacity limited to Multihub; this paper allocated the emergency supplies at each demand point to Multihub from which the emergency supply would be transferred. Secondly, this paper searched for the optimal plans from some feasible plans to determine the distribution directions and emergency supplies collection amount at emergency supplies provision points as well as the optimal collection cost that meet the constraint of demand time. Finally, the result of case verification showed that, compared with simulated annealing (SA and sequential enumeration method (SEM, Multihub emergency supply collection model based on PSO parallel algorithm made a great improvement in the number of iterations and the optimal collection time, indicating that this model is feasible and effective and can be used in decision-making for earthquake emergency supply collection.

  11. A green supply chain network design model for enhancing competitiveness and sustainability of companies in high north arctic regions

    Directory of Open Access Journals (Sweden)

    Hao Yu, Wei Deng Solvang, Chen Chen

    2014-01-01

    Full Text Available To survive in today’s competitive and ever-changing marketplace, companies need not only to engage in their products and/or services, but also to focus on the management of the whole supply chain. Effectively managing and balancing the profitability and interconnection of each player in the supply chain will improve the overall supply chain surplus as well as individual profit. However, it is extremely difficult to simultaneously optimize several objectives in design and planning of a supply chain, i.e., cost-minimization, risk-minimization, responsiveness-maximization, etc., which are somehow conflict with one another. Furthermore, the natural and infrastructural challenges in high north arctic regions make it become much more difficult and complicated to design and develop cost-efficient, highly responsive, environmentally friendly, and sustainable supply chain network. In order to provide companies in high north arctic regions with decision support tool for the design and planning of theirs supply chain networks, a green supply chain network design (GrSCND model is formulated in this study based on multi-objective mixed integer programming (MIP. The optimal trade-off among several conflicting objectives is the focus of this GrSCND model aiming to enhance both competitive competence and sustainability of companies and supply chains operated in high north regions. In addition, a numerical experiment is also given to present a deep insight of the GrSCND model.

  12. Receptor modeling of C2─C7 hydrocarbon sources at an urban background site in Zurich, Switzerland: changes between 1993─1994 and 2005─2006

    Directory of Open Access Journals (Sweden)

    S. Reimann

    2008-05-01

    Full Text Available Hourly measurements of 13 volatile hydrocarbons (C2–C7 were performed at an urban background site in Zurich (Switzerland in the years 1993–1994 and again in 2005–2006. For the separation of the volatile organic compounds by gas-chromatography (GC, an identical chromatographic column was used in both campaigns. Changes in hydrocarbon profiles and source strengths were recovered by positive matrix factorization (PMF. Eight and six factors could be related to hydrocarbon sources in 1993–1994 and in 2005–2006, respectively. The modeled source profiles were verified by hydrocarbon profiles reported in the literature. The source strengths were validated by independent measurements, such as inorganic trace gases (NOx, CO, SO2, methane (CH4, oxidized hydrocarbons (OVOCs and meteorological data (temperature, wind speed etc.. Our analysis suggests that the contribution of most hydrocarbon sources (i.e. road traffic, solvents use and wood burning decreased by a factor of about two to three between the early 1990s and 2005–2006. On the other hand, hydrocarbon losses from natural gas leakage remained at relatively constant levels (−20%. The estimated emission trends are in line with the results from different receptor-based approaches reported for other European cities. Their differences to national emission inventories are discussed.

  13. Interorganizational Knowledge Division Decision Model Based on Cooperative Innovation of Supply Chain System

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-01-01

    Full Text Available Within interorganizational cooperative innovation of construction supply chain system, the achievement of project value-adding could be reflected by several factors, such as project-based organizational effect level, and the relationship between project cooperative innovation objectives. In this paper, based on the assumption of equal cooperation between project-based organizations, we selected the knowledge cooperation between the owner and contractor in construction supply chain system as research object. From the perspective of maximizing project value-adding and the relationship of effort cost between knowledge input and innovation stage in consideration, we established the knowledge collaborative incentive model for interorganizational cooperative innovation of construction supply chain system and proposed the first-order and second-order approaches. Then we conducted the digital simulation and example analysis, its results showed that if the owner has the capability to achieve project value-adding in knowledge cooperation, he would adopt a part commissioned way. Otherwise, a fully commissioned way would be better.

  14. An open source hydroeconomic model for California's water supply system: PyVIN

    Science.gov (United States)

    Dogan, M. S.; White, E.; Herman, J. D.; Hart, Q.; Merz, J.; Medellin-Azuara, J.; Lund, J. R.

    2016-12-01

    Models help operators and decision makers explore and compare different management and policy alternatives, better allocate scarce resources, and predict the future behavior of existing or proposed water systems. Hydroeconomic models are useful tools to increase benefits or decrease costs of managing water. Bringing hydrology and economics together, these models provide a framework for different disciplines that share similar objectives. This work proposes a new model to evaluate operation and adaptation strategies under existing and future hydrologic conditions for California's interconnected water system. This model combines the network structure of CALVIN, a statewide optimization model for California's water infrastructure, along with an open source solver written in the Python programming language. With the flexibilities of the model, reservoir operations, including water supply and hydropower, groundwater pumping, and the Delta water operations and requirements can now be better represented. Given time series of hydrologic inputs to the model, typical outputs include urban, agricultural and wildlife refuge water deliveries and shortage costs, conjunctive use of surface and groundwater systems, and insights into policy and management decisions, such as capacity expansion and groundwater management policies. Water market operations also represented in the model, allocating water from lower-valued users to higher-valued users. PyVIN serves as a cross-platform, extensible model to evaluate systemwide water operations. PyVIN separates data from the model structure, enabling model to be easily applied to other parts of the world where water is a scarce resource.

  15. Multi-Commodity Flow and Multi-Period Equilibrium Model of Supply Chain Network with Postponement Strategy

    Directory of Open Access Journals (Sweden)

    Peng Yang

    2013-02-01

    Full Text Available With the constant changes of the market demand trends and modern information technology which greatly influence supply chain operation and management, postponement has been developed to be an important strategy in some of the supply chain processes. This paper studies the multi-period and multi-commodity flow supply chain network equilibrium problem with postponement strategy under a type of supply chain management pattern. Taking the influences of the relationship between orders and inventory management of supply chain into consideration, and employing variational inequality to establish multi-period equilibrium model at each level and network equilibrium model , this paper eventually works out the conditions to make the system achieve equilibrium, and also offers economic interpretation with concrete examples to verify them.

  16. Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Watson, G.; Baylaucq, A.

    2006-01-01

    measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of +/- 1%. A total of 208 experimental datapoints are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume, and the breaking or weakening of hydrogen bonds...... viscosity models with a physical and theoretical background. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. In addition to these models, the simple compositional models by Grunberg......-Nissan and Katti-Chaudhri have also been applied. Overall a satisfactory representation of the viscosity of these two binary ethanol + C-7 hydrocarbon systems is found for the different models within the considered T, P range taking into account their simplicity....

  17. A Mathematical Model Based on Supply Chain Optimization for International Petrochemical Engineering Projects

    Institute of Scientific and Technical Information of China (English)

    Gao Ning; Sun Wei

    2015-01-01

    Based on the study of supply chain (SC) and SC optimization in engineering projects, a mixed integer nonlinear programming (MINLP) optimization model is developed to minimize the total SC cost for international petrochemical en-gineering projects. A steam cracking project is selected and analyzed, from which typical SC characteristics in international engineering projects in the area of petrochemical industry are summarized. The MINLP model is therefore developed and applied to projects with detailed data. The optimization results are analyzed and compared by the MINLP model, indicat-ing that they are appropriate to SC management practice in engineering projects, and are consistent with the optimal price-effective strategy in procurement. As a result, the model could provide useful guidance to SC optimization of international engineering projects in petrochemical industry, and improve SC management by selecting more reliable and qualiifed part-ner enterprises in SC for the project.

  18. Spatial distribution of hydrocarbon reservoirs in the West Korea Bay Basin in the northern part of the Yellow Sea, estimated by 3-D gravity forward modelling

    Science.gov (United States)

    Choi, Sungchan; Ryu, In-Chang; Götze, H.-J.; Chae, Y.

    2017-01-01

    Although an amount of hydrocarbon has been discovered in the West Korea Bay Basin (WKBB), located in the North Korean offshore area, geophysical investigations associated with these hydrocarbon reservoirs are not permitted because of the current geopolitical situation. Interpretation of satellite-derived potential field data can be alternatively used to image the 3-D density distribution in the sedimentary basin associated with hydrocarbon deposits. We interpreted the TRIDENT satellite-derived gravity field data to provide detailed insights into the spatial distribution of sedimentary density structures in the WKBB. We used 3-D forward density modelling for the interpretation that incorporated constraints from existing geological and geophysical information. The gravity data interpretation and the 3-D forward modelling showed that there are two modelled areas in the central subbasin that are characterized by very low density structures, with a maximum density of about 2000 kg m-3, indicating some type of hydrocarbon reservoir. One of the anticipated hydrocarbon reservoirs is located in the southern part of the central subbasin with a volume of about 250 km3 at a depth of about 3000 m in the Cretaceous/Jurassic layer. The other hydrocarbon reservoir should exist in the northern part of the central subbasin, with an average volume of about 300 km3 at a depth of about 2500 m.

  19. Mathematical modeling of the biodegradation of residual hydrocarbon in a variably-saturated sand column.

    Science.gov (United States)

    Geng, Xiaolong; Boufadel, Michel C; Wrenn, Brian

    2013-04-01

    The biodegradation of heptadecane in five sand columns was modeled using a multiplicative Monod approach. Each column contained 1.0 kg of sand and 2 g of heptadecane, and was supplied with an artificial seawater solution containing nutrients at a flow rate that resulted in unsaturated flow through the column. All nutrients were provided in excess with the exception of nitrate whose influent concentration was 0.1, 0.5, 1.0, 2.5, or 5.0 mg N/L. The experiment was run around 912 h until no measurable oxygen consumption or CO2 production was observed. The residual mass of heptadecane was measured at the end of the experiments and the biodegradation was monitored based on oxygen consumption and CO2 production. Biodegradation kinetic parameters were estimated by fitting the model to experimental data of oxygen, CO2, and residual mass of heptadecane obtained from the two columns having influent nitrate-N concentration of 0.5 and 2.5 mg/L. Noting that the oxygen and CO2 measurements leveled off at around 450 h, we fitted the model to these data for that range. The estimated parameters fell in within the range reported in the literature. In particular, the half-saturation constant for nitrate utilization, [Formula: see text], was estimated to be 0.45 mg N/L, and the yield coefficient was found to be 0.15 mg biomass/mg heptadecane. Using these values, the rest of experimental data from the five columns was predicted, and the model agreed with the observations. There were some consistent discrepancies at large times between the model simulation and observed data in the cases with higher nitrate concentration. One plausible explanation for these differences could be limitation of biodegradation by reduction of the heptadecane-water interfacial area in these columns while the model uses a constant interfacial area.

  20. Optimal production lot sizing model in a supply chain with periodically fixed demand considering learning effect

    Institute of Scientific and Technical Information of China (English)

    熊中楷; SHEN; Tiesong

    2002-01-01

    This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity.An algorithm is employed to find theoptimal dela time for production and production time sequentially.It is found that the optimal delay time for production and the production time are not static,but dynamic and variant with time.It is important for a manufacturer to schedule the production so as to prevent facilities and workers from idling.

  1. A GRASP model in network design for two-stage supply chain

    Directory of Open Access Journals (Sweden)

    Hassan Javanshir

    2011-04-01

    Full Text Available We consider a capacitated facility location problem (CFLP which contains a production facility and distribution centers (DCs supplying retailers' demand. The primary purpose is to locate distribution centres in the network and the objective is the minimization of the sum of fixed facility location, pipeline inventory, safety stock and lost sales. We use Greedy randomized adaptive search procedures (GRASP to solve the model. The preliminary results indicate that the proposed method of this paper could provide competitive results in reasonable amount time.

  2. Inter-basin water transfer-supply model and risk analysis with consideration of rainfall forecast information

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper develops a new inter-basin water transfer-supply and risk assessment model with consideration of rainfall forecast information. Firstly, based on the current state of reservoir and rainfall forecast information from the global forecast system (GFS), the actual diversion amount can be determined according to the inter-basin water transfer rules with the decision tree method; secondly, the reservoir supply operation system is used to distribute water resource of the inter-basin water transfer reservoir; finally, the integrated risk assessment model is built by selecting the reliability of water transfer, the reliability (water shortage risk), the resiliency and the vulnerability of water supply as risk analysis indexes. The case study shows that the inter-basin water transfer-supply model with rainfall forecast information considered can reduce the comprehensive risk and improve the utilization efficiency of water resource, as compared with conventional and optimal water distribution models.

  3. A Comprehensive Mathematical Programming Model for Minimizing Costs in A Multiple-Item Reverse Supply Chain with Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    Mahmoudi Hoda

    2014-09-01

    Full Text Available These instructions give you guidelines for preparing papers for IFAC conferences. A reverse supply chain is configured by a sequence of elements forming a continuous process to treat return-products until they are properly recovered or disposed. The activities in a reverse supply chain include collection, cleaning, disassembly, test and sorting, storage, transport, and recovery operations. This paper presents a mathematical programming model with the objective of minimizing the total costs of reverse supply chain including transportation, fixed opening, operation, maintenance and remanufacturing costs of centers. The proposed model considers the design of a multi-layer, multi-product reverse supply chain that consists of returning, disassembly, processing, recycling, remanufacturing, materials and distribution centers. This integer linear programming model is solved by using Lingo 9 software and the results are reported. Finally, a sensitivity analysis of the proposed model is also presented.

  4. The energy supply planning model. Volume II. User's manual and appendices. Final report, December 1973--August 1975

    Energy Technology Data Exchange (ETDEWEB)

    Carasso, M.; Gallagher, J.M.; Sharma, K.J.; Gayle, J.R.; Barany, R.

    1975-08-01

    The specific modeling work reported here was stimulated by the need to explore the feasibility of proposed U.S. energy policies in terms of the requirements for specific societal resources associated with the construction and operation of energy supply and energy transportation facilities needed to implement these energy supply policies. The Energy Supply Planning Model is designed to covert future (1975 to 1995) energy mixes to resource requirements schedules. With this planning tool, the feasibility of various proposed mixes can be assessed in terms of the time, capital, manpower, materials, and construction schedules required for the specified energy supply system. In carrying out the modeling efforts, special emphasis was placed on developing a rather transparent planning model where the user can test the implications of different energy policy options.

  5. An order insertion scheduling model of logistics service supply chain considering capacity and time factors.

    Science.gov (United States)

    Liu, Weihua; Yang, Yi; Wang, Shuqing; Liu, Yang

    2014-01-01

    Order insertion often occurs in the scheduling process of logistics service supply chain (LSSC), which disturbs normal time scheduling especially in the environment of mass customization logistics service. This study analyses order similarity coefficient and order insertion operation process and then establishes an order insertion scheduling model of LSSC with service capacity and time factors considered. This model aims to minimize the average unit volume operation cost of logistics service integrator and maximize the average satisfaction degree of functional logistics service providers. In order to verify the viability and effectiveness of our model, a specific example is numerically analyzed. Some interesting conclusions are obtained. First, along with the increase of completion time delay coefficient permitted by customers, the possible inserting order volume first increases and then trends to be stable. Second, supply chain performance reaches the best when the volume of inserting order is equal to the surplus volume of the normal operation capacity in mass service process. Third, the larger the normal operation capacity in mass service process is, the bigger the possible inserting order's volume will be. Moreover, compared to increasing the completion time delay coefficient, improving the normal operation capacity of mass service process is more useful.

  6. An Order Insertion Scheduling Model of Logistics Service Supply Chain Considering Capacity and Time Factors

    Directory of Open Access Journals (Sweden)

    Weihua Liu

    2014-01-01

    Full Text Available Order insertion often occurs in the scheduling process of logistics service supply chain (LSSC, which disturbs normal time scheduling especially in the environment of mass customization logistics service. This study analyses order similarity coefficient and order insertion operation process and then establishes an order insertion scheduling model of LSSC with service capacity and time factors considered. This model aims to minimize the average unit volume operation cost of logistics service integrator and maximize the average satisfaction degree of functional logistics service providers. In order to verify the viability and effectiveness of our model, a specific example is numerically analyzed. Some interesting conclusions are obtained. First, along with the increase of completion time delay coefficient permitted by customers, the possible inserting order volume first increases and then trends to be stable. Second, supply chain performance reaches the best when the volume of inserting order is equal to the surplus volume of the normal operation capacity in mass service process. Third, the larger the normal operation capacity in mass service process is, the bigger the possible inserting order’s volume will be. Moreover, compared to increasing the completion time delay coefficient, improving the normal operation capacity of mass service process is more useful.

  7. Evaluating Supply Chain Management: A Methodology Based on a Theoretical Model

    Directory of Open Access Journals (Sweden)

    Alexandre Tadeu Simon

    2015-01-01

    Full Text Available Despite the increasing interest in supply chain management (SCM by researchers and practitioners, there is still a lack of academic literature concerning topics such as methodologies to guide and support SCM evaluation. Most developed methodologies have been provided by consulting companies and are restricted in their publication and use. This article presents a methodology for evaluating companies’ degree of adherence to a SCM conceptual model. The methodology is based on Cooper, Lambert and Pagh’s original contribution and involves analysis of eleven referential axes established from key business processes, horizontal structures, and initiatives & practices. We analyze the applicability of the proposed model based on findings from interviews with experts - academics and practitioners - as well as from case studies of three focal firms and their supply chains. In general terms, the methodology can be considered a diagnostic instrument that allows companies to evaluate their maturity regarding SCM practices. From this diagnosis, firms can identify and implement activities to improve degree of adherence to the reference model and achieve SCM benefits. The methodology aims to contribute to SCM theory development. It is an initial, but structured, reference for translating a theoretical approach into practical aspects.

  8. Elastic Labour Supply and Home Production in a Monetary Growth Model

    Directory of Open Access Journals (Sweden)

    Wei-Bin Zhang

    2011-10-01

    Full Text Available This study constructs a monetary gender growth model with capital accumulation and endogenous labour supply. The real aspects of the model are based on the neoclassical growth theory and monetary aspects of the model are based on the cash-in-advance (CIA approach. We show that the dynamics of the economy can be described by 2-dimensional differential equations. We simulate equilibrium and motion of the economy with specified monetary policies, household preference and technology. As the monetary economic system is unstable, the economy may either experience unlimited growth or economic crisis. We also study effects of changes in some parameters on the economic equilibrium. For instance, as the woman raises her propensity to stay at home, the capital intensity is not affected, which results in that the wage rates, the rate and output level per unit of labour input are not affected. Nevertheless, the man increases his work time and the woman reduces her work time, resulting in the fall of the labour supply. The money holing, durable goods used at home and consumption level per household are reduced; also the total wealth, total capital inputs, total durable goods and total output levels are reduced.

  9. A Split-Path Schema-Based RFID Data Storage Model in Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Jianfeng Zhang

    2013-05-01

    Full Text Available In modern supply chain management systems, Radio Frequency IDentification (RFID technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing approaches cannot satisfy the requirements of RFID data management. In this paper, we present a split-path schema-based RFID data storage model. With a data separation mechanism, the massive RFID data produced in supply chain management systems can be stored and processed more efficiently. Then a tree structure-based path splitting approach is proposed to intelligently and automatically split the movement paths of products . Furthermore, based on the proposed new storage model, we design the relational schema to store the path information and time information of tags, and some typical query templates and SQL statements are defined. Finally, we conduct various experiments to measure the effect and performance of our model and demonstrate that it performs significantly better than the baseline approach in both the data expression and path-oriented RFID data query performance.

  10. An Order Insertion Scheduling Model of Logistics Service Supply Chain Considering Capacity and Time Factors

    Science.gov (United States)

    Yang, Yi; Wang, Shuqing; Liu, Yang

    2014-01-01

    Order insertion often occurs in the scheduling process of logistics service supply chain (LSSC), which disturbs normal time scheduling especially in the environment of mass customization logistics service. This study analyses order similarity coefficient and order insertion operation process and then establishes an order insertion scheduling model of LSSC with service capacity and time factors considered. This model aims to minimize the average unit volume operation cost of logistics service integrator and maximize the average satisfaction degree of functional logistics service providers. In order to verify the viability and effectiveness of our model, a specific example is numerically analyzed. Some interesting conclusions are obtained. First, along with the increase of completion time delay coefficient permitted by customers, the possible inserting order volume first increases and then trends to be stable. Second, supply chain performance reaches the best when the volume of inserting order is equal to the surplus volume of the normal operation capacity in mass service process. Third, the larger the normal operation capacity in mass service process is, the bigger the possible inserting order's volume will be. Moreover, compared to increasing the completion time delay coefficient, improving the normal operation capacity of mass service process is more useful. PMID:25276851

  11. SUPPLY –CHAIN AND LOGIC MODELS FOR THE TEXTILE AND CLOTHING COMPANIES

    Directory of Open Access Journals (Sweden)

    VISILEANU Emilia

    2014-05-01

    Full Text Available The textile and clothing industry is characterized by specific supply-chain models with companies situated in a complex cluster type structure. Depending on the size, the volume and the variety of production, companies can be classified as follows: large companies, griffes, medium size companies and subcontracting companies. The logic of companies is defined by the main feature of the textile and clothing field, namely the logic of collections, determined by the seasonality and classified into several types: planning, fast-fashion, fast fashion/ planning. The market share defined by stylistic content, product quality and price determine their typology: mass-market, bridge, diffusion, prêt-a-porter/haute-couture. The study conducted on a number of companies in the textile-clothing industry revealed the following: high share of SMEs (75%, dominant role of garments in the production (74.5%, fast-fashion logic of imitating companies is predominant (94% and mass-market type products have the highest market share (71%. Success in national and international challenges that must be faced by the textile - clothing sector: complete liberalization of world trade, the implementation of quality standards, the adoption of the EU Customs Code and relocation can be provided only by changing the supply -chain models and business strategies with a focus on short series products with high customization and fictionalization, new models of e-commerce services, e-business, etc

  12. The development of a canine anorectal autotransplantation model based on blood supply: a preliminary case report.

    Directory of Open Access Journals (Sweden)

    Jun Araki

    Full Text Available Colostomy is conventionally the only treatment for anal dysfunction. Recently, a few trials of anorectal transplantation in animals have been published; however, further development of this technique is required. Moreover, it is crucial to perform this research in dogs, which resemble humans in anorectal anatomy and biology. We designed a canine anorectal transplantation model, wherein anorectal autotransplantation was performed by anastomoses of the rectum, inferior mesenteric artery (IMA and vein, and pudendal nerves. Resting pressure in the anal canal and anal canal pressure fluctuation were measured before and after surgery. Graft pathology was examined three days after surgery. The anal blood supply was compared with that in three beagles using indocyanine green (ICG fluorescence angiography. The anorectal graft had sufficient arterial blood supply from the IMA; however, the graft's distal end was congested and necrotized. Functional examination demonstrated reduced resting pressure and the appearance of an irregular anal canal pressure wave after surgery. ICG angiography showed that the pudendal arteries provided more blood flow than the IMA to the anal segment. This is the first canine model of preliminary anorectal autotransplantation, and it demonstrates the possibility of establishing a transplantation model in dogs using appropriate vascular anastomoses, thus contributing to the progress of anorectal transplantation.

  13. A hydrologic-economic modeling approach for analysis of urban water supply dynamics in Chennai, India

    Science.gov (United States)

    Srinivasan, Veena; Gorelick, Steven M.; Goulder, Lawrence

    2010-07-01

    In this paper, we discuss a challenging water resources problem in a developing world city, Chennai, India. The goal is to reconstruct past system behavior and diagnose the causes of a major water crisis. In order to do this, we develop a hydrologic-engineering-economic model to address the complexity of urban water supply arising from consumers' dependence on multiple interconnected sources of water. We integrate different components of the urban water system: water flowing into the reservoir system; diversion and distribution by the public water utility; groundwater flow in the aquifer beneath the city; supply, demand, and prices in the informal tanker-truck-based water market; and consumer behavior. Both the economic and physical impacts of consumers' dependence on multiple sources of water are quantified. The model is calibrated over the period 2002-2006 using a range of hydrologic and socio-economic data. The model's results highlight the inadequacy of the reservoir system and the buffering role played by the urban aquifer and consumers' coping investments during multiyear droughts.

  14. Design and Modelling of Sustainable Bioethanol Supply Chain by Minimizing the Total Ecological Footprint in Life Cycle Perspective

    DEFF Research Database (Denmark)

    Ren, Jingzheng; Manzardo, Alessandro; Toniolo, Sara

    2013-01-01

    The purpose of this paper is to develop a model for designing the most sustainable bioethanol supply chain. Taking into consideration of the possibility of multiple-feedstock, multiple transportation modes, multiple alternative technologies, multiple transport patterns and multiple waste disposal...... manners in bioethanol systems, this study developed a model for designing the most sustainable bioethanol supply chain by minimizing the total ecological footprint under some prerequisite constraints including satisfying the goal of the stakeholders', the limitation of resources and energy, the capacity...

  15. Designing a mathematical model for integrating dynamic cellular manufacturing into supply chain system

    Science.gov (United States)

    Aalaei, Amin; Davoudpour, Hamid

    2012-11-01

    This article presents designing a new mathematical model for integrating dynamic cellular manufacturing into supply chain system with an extensive coverage of important manufacturing features consideration of multiple plants location, multi-markets allocation, multi-period planning horizons with demand and part mix variation, machine capacity, and the main constraints are demand of markets satisfaction in each period, machine availability, machine time-capacity, worker assignment, available time of worker, production volume for each plant and the amounts allocated to each market. The aim of the proposed model is to minimize holding and outsourcing costs, inter-cell material handling cost, external transportation cost, procurement & maintenance and overhead cost of machines, setup cost, reconfiguration cost of machines installation and removal, hiring, firing and salary worker costs. Aimed to prove the potential benefits of such a design, presented an example is shown using a proposed model.

  16. Heavy oil supply economics and supply response to low oil prices

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, L. [Canadian Energy Research Inst., Calgary, AB (Canada)

    1999-04-01

    The dynamics of the heavy oil industry are examined, including prices, market demand, supply and supply costs. Price assumptions are provided for the reference case oil price (west Texas intermediate at Cushing). Supply cost methodology is explained. Capital and operating costs for various heavy oil and synthetic sources are derived from modeling results. The range of supply costs for heavy oil and bitumen from various sources, supply costs in terms of reference case market values and in terms of 1995-1996 average market values for Bow River crude, are derived. The CERI long term supply forecast model is explained. Western Canada upstream oil and gas cash flow and capital expenditures, eastern Canada exploration and expenditures by hydrocarbon type, and Canadian heavy oil and bitumen production based on reference case prices are estimated. Based on these projections the outlook for heavy oil at reference case prices for better than average quality resources is judged to be economic. Lower quality resources will require technology gains for successful commercialization. SAGD is a likely candidate in this respect. Again based on reference prices, production is forecast to decline by 100 Kb/d over the next five years. Diluent supply is considered to be adequate throughout the forecast period. As far as thermal bitumen is concerned, the growth could, in fact, exceed the projection, but if so, more upgrading will be required. 11 figs.

  17. Linking state-and-transition simulation and timber supply models for forest biomass production scenarios

    Directory of Open Access Journals (Sweden)

    Jennifer K. Costanza

    2015-03-01

    Full Text Available We linked state-and-transition simulation models (STSMs with an economics-based timber supply model to examine landscape dynamics in North Carolina through 2050 for three scenarios of forest biomass production. Forest biomass could be an important source of renewable energy in the future, but there is currently much uncertainty about how biomass production would impact landscapes. In the southeastern US, if forests become important sources of biomass for bioenergy, we expect increased land-use change and forest management. STSMs are ideal for simulating these landscape changes, but the amounts of change will depend on drivers such as timber prices and demand for forest land, which are best captured with forest economic models. We first developed state-and-transition model pathways in the ST-Sim software platform for 49 vegetation and land-use types that incorporated each expected type of landscape change. Next, for the three biomass production scenarios, the SubRegional Timber Supply Model (SRTS was used to determine the annual areas of thinning and harvest in five broad forest types, as well as annual areas converted among those forest types, agricultural, and urban lands. The SRTS output was used to define area targets for STSMs in ST-Sim under two scenarios of biomass production and one baseline, business-as-usual scenario. We show that ST-Sim output matched SRTS targets in most cases. Landscape dynamics results indicate that, compared with the baseline scenario, forest biomass production leads to more forest and, specifically, more intensively managed forest on the landscape by 2050. Thus, the STSMs, informed by forest economics models, provide important information about potential landscape effects of bioenergy production.

  18. Linking state-and-transition simulation and timber supply models for forest biomass production scenarios

    Science.gov (United States)

    Costanza, Jennifer; Abt, Robert C.; McKerrow, Alexa; Collazo, Jaime

    2015-01-01

    We linked state-and-transition simulation models (STSMs) with an economics-based timber supply model to examine landscape dynamics in North Carolina through 2050 for three scenarios of forest biomass production. Forest biomass could be an important source of renewable energy in the future, but there is currently much uncertainty about how biomass production would impact landscapes. In the southeastern US, if forests become important sources of biomass for bioenergy, we expect increased land-use change and forest management. STSMs are ideal for simulating these landscape changes, but the amounts of change will depend on drivers such as timber prices and demand for forest land, which are best captured with forest economic models. We first developed state-and-transition model pathways in the ST-Sim software platform for 49 vegetation and land-use types that incorporated each expected type of landscape change. Next, for the three biomass production scenarios, the SubRegional Timber Supply Model (SRTS) was used to determine the annual areas of thinning and harvest in five broad forest types, as well as annual areas converted among those forest types, agricultural, and urban lands. The SRTS output was used to define area targets for STSMs in ST-Sim under two scenarios of biomass production and one baseline, business-as-usual scenario. We show that ST-Sim output matched SRTS targets in most cases. Landscape dynamics results indicate that, compared with the baseline scenario, forest biomass production leads to more forest and, specifically, more intensively managed forest on the landscape by 2050. Thus, the STSMs, informed by forest economics models, provide important information about potential landscape effects of bioenergy production.

  19. Modeling and Dynamical Analysis of the Water Resources Supply-Demand System: A Case Study in Haihe River Basin

    Directory of Open Access Journals (Sweden)

    Chongli Di

    2014-01-01

    Full Text Available The relationship between water resources supply and demand is very complex and exhibits nonlinear characteristics, which leads to fewer models that can adequately manage the dynamic evolution process of the water resources supply-demand system. In this paper, we propose a new four-dimensional dynamical model to simulate the internal dynamic evolution process and predict future trends of water supply and demand. At the beginning, a new four-dimensional dynamical model with uncertain parameters is established. Then, the gray code hybrid accelerating genetic algorithm (GHAGA is adopted to identify the unknown parameters of the system based on the statistic data (1998–2009. Finally, the dynamical analysis of the system is further studied by Lyapunov-exponent, phase portraits, and Lyapunov exponent theory. Numerical simulation results demonstrate that the proposed water resources supply-demand system is in a steady state and is suitable for simulating the dynamical characteristics of a complex water supply and demand system. According to the trends of the water supply and demand of several nonlinear simulation cases, the corresponding measures can be proposed to improve the steady development of the water resources supply-demand system.

  20. A Mixed Integer Linear Programming Model for the Design of Remanufacturing Closed–loop Supply Chain Network

    Directory of Open Access Journals (Sweden)

    Mbarek Elbounjimi

    2015-11-01

    Full Text Available Closed-loop supply chain network design is a critical issue due to its impact on both economic and environmental performances of the supply chain. In this paper, we address the problem of designing a multi-echelon, multi-product and capacitated closed-loop supply chain network. First, a mixed-integer linear programming formulation is developed to maximize the total profit. The main contribution of the proposed model is addressing two economic viability issues of closed-loop supply chain. The first issue is the collection of sufficient quantity of end-of-life products are assured by retailers against an acquisition price. The second issue is exploiting the benefits of colocation of forward facilities and reverse facilities. The presented model is solved by LINGO for some test problems. Computational results and sensitivity analysis are conducted to show the performance of the proposed model.

  1. Development of a model for activated sludge aeration systems: linking air supply, distribution, and demand.

    Science.gov (United States)

    Schraa, Oliver; Rieger, Leiv; Alex, Jens

    2017-02-01

    During the design of a water resource recovery facility, it is becoming industry practice to use simulation software to assist with process design. Aeration is one of the key components of the activated sludge process, and is one of the most important aspects of modelling wastewater treatment systems. However, aeration systems are typically not modelled in detail in most wastewater treatment process modelling studies. A comprehensive dynamic aeration system model has been developed that captures both air supply and demand. The model includes sub-models for blowers, pipes, fittings, and valves. An extended diffuser model predicts both oxygen transfer efficiency within an aeration basin and pressure drop across the diffusers. The aeration system model allows engineers to analyse aeration systems as a whole to determine biological air requirements, blower performance, air distribution, control valve impacts, controller design and tuning, and energy costs. This enables engineers to trouble-shoot the entire aeration system including process, equipment and controls. It also allows much more realistic design of these highly complex systems.

  2. Closed-Loop Supply Chain Models with Considering the Environmental Impact

    Directory of Open Access Journals (Sweden)

    Amir Mohajeri

    2014-01-01

    Full Text Available Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.

  3. Closed-loop supply chain models with considering the environmental impact.

    Science.gov (United States)

    Mohajeri, Amir; Fallah, Mohammad

    2014-01-01

    Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.

  4. A ternary age-mixing model to explain contaminant occurrence in a deep supply well.

    Science.gov (United States)

    Jurgens, Bryant C; Bexfield, Laura M; Eberts, Sandra M

    2014-09-01

    The age distribution of water from a public-supply well in a deep alluvial aquifer was estimated and used to help explain arsenic variability in the water. The age distribution was computed using a ternary mixing model that combines three lumped parameter models of advection-dispersion transport of environmental tracers, which represent relatively recent recharge (post-1950s) containing volatile organic compounds (VOCs), old intermediate depth groundwater (about 6500 years) that was free of drinking-water contaminants, and very old, deep groundwater (more than 21,000 years) containing arsenic above the USEPA maximum contaminant level of 10 µg/L. The ternary mixing model was calibrated to tritium, chloroflorocarbon-113, and carbon-14 (14C) concentrations that were measured in water samples collected on multiple occasions. Variability in atmospheric 14C over the past 50,000 years was accounted for in the interpretation of (14) C as a tracer. Calibrated ternary models indicate the fraction of deep, very old groundwater entering the well varies substantially throughout the year and was highest following long periods of nonoperation or infrequent operation, which occured during the winter season when water demand was low. The fraction of young water entering the well was about 11% during the summer when pumping peaked to meet water demand and about 3% to 6% during the winter months. This paper demonstrates how collection of multiple tracers can be used in combination with simplified models of fluid flow to estimate the age distribution and thus fraction of contaminated groundwater reaching a supply well under different pumping conditions.

  5. Aggregate supply and demand modeling using GIS methods for the front range urban corridor, Colorado

    Science.gov (United States)

    Karakas, Ahmet; Turner, Keith

    2004-07-01

    The combined use of allocation modeling and geographical information system (GIS) technologies for providing quantitative assessments of aggregate supply and demand is evaluated using representative data for the Front Range Urban Corridor (FRUC) in Colorado. The FRUC extends from the Colorado-Wyoming border to south of Colorado Springs, and includes Denver and the major urban growth regions of Colorado. In this area, aggregate demand is high and is increasing in response to population growth. Neighborhood opposition to the establishment of new pits and quarries and the depletion of many deposits are limiting aggregate supplies. Many sources are already covered by urban development or eliminated from production by zoning. Transport of aggregate by rail from distant resources may be required in the future. Two allocation-modeling procedures are tested in this study. Network analysis procedures provided within the ARC/INFO software, are unsatisfactory. Further aggregate allocation modeling used a model specifically designed for this task; a modified version of an existing Colorado School of Mines allocation model allows for more realistic market analyses. This study evaluated four scenarios. The entire region was evaluated with a scenario reflecting the current market and by a second scenario in which some existing suppliers were closed down and new potential suppliers were activated. The conditions within the Denver metropolitan area were studied before and after the introduction of three possible rail-to-truck aggregate distribution centers. GIS techniques are helpful in developing the required database to describe the Front Range Urban Corridor aggregate market conditions. GIS methods allow the digital representation of the regional road network, and the development of a distance matrix relating all suppliers and purchasers.

  6. Modelling, stability and control of voltage behaviour in power supply systems

    Energy Technology Data Exchange (ETDEWEB)

    Hill, David J. [Sydney Univ., NSW (Australia). Dept. of Electrical Engineering; Hisken, Ian A. [Newcastle Univ., NSW (Australia). Dept. of Electrical and Computer Engineering

    1994-12-31

    This paper gives an overview of a line of work on mid to long term voltages stability analysis and control in power systems. The results are based on use of a novel approach to dynamic load modelling using aggregate nonlinear structures. In general, the model for the transmission network and supply end dynamics is of the hybrid differential - algebraic - discrete kind. Various stability questions are precisely formulated and analysed in terms of network and load characteristics (steady-state and transient). The results are shown to be a useful framework for deriving criteria of the where, when and how much kind for various control actions such as load Thedding and tap-blocking. (author) 47 refs., 15 figs., 1 tab.

  7. A Fuzzy Multiobjective Model for Supplier Selection under Considering Stochastic Demand in a Supply Chain

    Directory of Open Access Journals (Sweden)

    Wei Pan

    2015-01-01

    Full Text Available With the development of market competition, company faces more and more pressures. Meanwhile, procurement has a vital effect on achieving competitive advantages in a supply chain. Selecting the appropriate suppliers is one of the most important sections in purchase management. However, in real situation, supplier selection is a multiple objective problem about different items with vagueness and randomness of the data. It is very complex. Hence, research about supplier selection is relatively scarce under considering multiple items, discount price, and fuzzy and stochastic information. In our paper, we develop a fuzzy multiobjective supplier selection model for overcoming uncertainty and multiple items. Stochastic demand, fuzzy objectives, and weights are simultaneously applied to help the managers to select the suitable suppliers about different items. For illustration purpose, a numerical example is presented to verify the effectiveness of the proposed model.

  8. Supply Chain Optimization of Integrated Glycerol Biorefinery: GlyThink Model Development and Application

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Carvalho, Ana; Gernaey, Krist

    2017-01-01

    for the integrated biorefinery; (iii) government incentives might play a decisive role in the growth of a glycerol-based economy showing improved economic feasibility; and, last, (iv) the optimal product portfolio suggested is based on the production of succinic acid and lactic acid, followed by epichlorohydrin....... To address the optimal design and planning of the glycerol-based biorefinery supply chain, in this work, we propose a multiperiod, multistage, and multiproduct Mixed Integer Linear Programming optimization model, called GlyThink, based upon the maximization of the net present value (NPV). The proposed model...... is able to identify operational decisions, including locations, capacity levels, technologies, and product portfolio, as well as strategic decisions such as inventory levels, production amounts, and transportation to the final markets. Several technologies are considered for the glycerol valorization...

  9. Determination of the periodicity and synchronization of anticipative agent based supply-demand model

    Science.gov (United States)

    Škraba, A.; Bren, M.; Kofjač, D.

    2017-02-01

    The paper presents the transformation of cobweb model by including the anticipation about the supply and demand. Developed transformation leads to oscillatory behaviour. The periodic conditions of the model have been analytically determined by the application of z-transform. Periodic solutions of the system are presented in the form of an inverse Farey tree, where the Golden Ratio path could be observed. The table of periodic conditions is given up to period 8. The agent-based system was developed in order to show the possibility of controlling the system by varying the key parameter, which determines the frequency response of agents and their interaction. A note on application in the stock market has been provided.

  10. a Multi Objective Model for Optimization of a Green Supply Chain Network

    Science.gov (United States)

    Paksoy, Turan; Özceylan, Eren; Weber, Gerhard-Wilhelm

    2010-06-01

    This study develops a model of a closed-loop supply chain (CLSC) network which starts with the suppliers and recycles with the decomposition centers. As a traditional network design, we consider minimizing the all transportation costs and the raw material purchasing costs. To pay attention for the green impacts, different transportation choices are presented between echelons according to their CO2 emissions. The plants can purchase different raw materials in respect of their recyclable ratios. The focuses of this paper are conducting the minimizing total CO2 emissions. Also we try to encourage the customers to use recyclable materials as an environmental performance viewpoint besides minimizing total costs. A multi objective linear programming model is developed via presenting a numerical example. We close the paper with recommendations for future researches.

  11. An Inventory Controlled Supply Chain Model Based on Improved BP Neural Network

    Directory of Open Access Journals (Sweden)

    Wei He

    2013-01-01

    Full Text Available Inventory control is a key factor for reducing supply chain cost and increasing customer satisfaction. However, prediction of inventory level is a challenging task for managers. As one of the widely used techniques for inventory control, standard BP neural network has such problems as low convergence rate and poor prediction accuracy. Aiming at these problems, a new fast convergent BP neural network model for predicting inventory level is developed in this paper. By adding an error offset, this paper deduces the new chain propagation rule and the new weight formula. This paper also applies the improved BP neural network model to predict the inventory level of an automotive parts company. The results show that the improved algorithm not only significantly exceeds the standard algorithm but also outperforms some other improved BP algorithms both on convergence rate and prediction accuracy.

  12. Data sharing requirements of supply - And logistics innovations - Towards a maturity model

    NARCIS (Netherlands)

    Hofman, W.J.

    2016-01-01

    Supply - and logistics innovations require data of different, heterogeneous sources. Supply chain resilience for instance requires visibility of goods flows and data of planned infrastructure maintenance and unforeseen accidents or incidents that may cause delays. Technically, there are different wa

  13. A conceptual model for factors affecting the relationship between supply chain integration and customer delivery performance

    OpenAIRE

    Peyman Ghafari Ashtiani; Elahe Bosak

    2013-01-01

    Supply chain is a widely used concept around the world. Nowadays, companies need to integrate their production processes, from the raw materials to the end-user. Supply chain management is a phenomenon that achieves this in a way that ensures customers get reliable and fast service and high quality products at the lowest possible cost. There is very limited and sporadic research on supply chain integration and how it affects supply chain performance. Therefore there is no real understanding o...

  14. Global distribution and Gas-particle Partitioning of Polycyclic Aromatic Hydrocarbons - a Modelling Study

    Science.gov (United States)

    Lammel, G.; Sehili, A. M.

    2009-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are emitted in all combustion processes. Some undergo re-volatilisation (multi-hopping). Little is known about degradation pathways and the processes determining gas-particle partitioning (Lohmann & Lammel, 2004). Distribution and fate have no been studied on the global scale so far (except for emissions in Europe and Russia; Sehili & Lammel, 2007). Anthracene (ANT), fluoranthene (FLT) and benzo[a]pyrene (BAP) have been studied under present-day climate and each 3 scenarios of atmospheric degradation and gas-particle partitioning using an atmospheric general circulation model with embedded dynamic aerosol submodel, ECHAM-HAM (Stier et al., 2005) and re-volatilization from ground compartments (Semeena et al., 2006). 10 years were simulated with a time-step of 30 min and 2.8°x2.8° and 19 levels. Emissions were compiled based on emission factors in 27 major types of combustion technologies, scaled to 141 combustion technologies and their global distribution as of 1996 (1°x1°) according to fuel type and the PM1 emission factor (Bond et al., 2004). The emissions were entried uniformly throughout the entire simulation time. Scenarios tested: AD = adsorption (according to the Junge empirical relationship; Pankow, 1987), OB = absorption in organic matter and adsorption to soot (Lohmann & Lammel, 2004) without and DP = with degradation in the atmospheric particulate phase. Gas-particle partitioning in air influences drastically the atmospheric cycling, total environmental fate (e.g. compartmental distributions) and the long-range transport potential (LRTP) of the substances studied. The LRTP is mostly regional. Comparison with observed levels indicate that degradation in the particulate phase must be slower than in the gas-phase. Furthermore, the levels of semivolatile PAHs (ANT and FLT) at high latitudes and a European mid latitude site cannot be explained by partitioning due to adsorption alone, but point to both absorption into

  15. Arsenic-containing hydrocarbons are toxic in the in vivo model Drosophila melanogaster.

    Science.gov (United States)

    Meyer, S; Schulz, J; Jeibmann, A; Taleshi, M S; Ebert, F; Francesconi, K A; Schwerdtle, T

    2014-11-01

    Arsenic-containing hydrocarbons (AsHC) constitute one group of arsenolipids that have been identified in seafood. In this first in vivo toxicity study for AsHCs, we show that AsHCs exert toxic effects in Drosophila melanogaster in a concentration range similar to that of arsenite. In contrast to arsenite, however, AsHCs cause developmental toxicity in the late developmental stages of Drosophila melanogaster. This work illustrates the need for a full characterisation of the toxicity of AsHCs in experimental animals to finally assess the risk to human health related to the presence of arsenolipids in seafood.

  16. Assessing End-Of-Supply Risk of Spare Parts Using the Proportional Hazard Model

    NARCIS (Netherlands)

    X. Li (Xishu); R. Dekker (Rommert); C. Heij (Christiaan); M. Hekimoğlu (Mustafa)

    2016-01-01

    textabstractOperators of long field-life systems like airplanes are faced with hazards in the supply of spare parts. If the original manufacturers or suppliers of parts end their supply, this may have large impacts on operating costs of firms needing these parts. Existing end-of-supply evaluation me

  17. Assessing End-Of-Supply Risk of Spare Parts Using the Proportional Hazard Model

    NARCIS (Netherlands)

    X. Li (Xishu); R. Dekker (Rommert); C. Heij (Christiaan); M. Hekimoğlu (Mustafa)

    2016-01-01

    textabstractOperators of long field-life systems like airplanes are faced with hazards in the supply of spare parts. If the original manufacturers or suppliers of parts end their supply, this may have large impacts on operating costs of firms needing these parts. Existing end-of-supply evaluation

  18. Climate Change Impacts on Electricity Demand and Supply in the United States: A Multi-Model Comparison

    Science.gov (United States)

    This paper compares the climate change impacts on U.S. electricity demand and supply from three models: the Integrated Planning Model (IPM), the Regional Energy Deployment System (ReEDS) model, and GCAM. Rising temperatures cause an appreciable net increase in electricity demand....

  19. A three-dimensional model of fungal morphogenesis based on the vesicle supply center concept.

    Science.gov (United States)

    Gierz, G; Bartnicki-Garcia, S

    2001-01-21

    We developed a three-dimensional model of hyphal morphogenesis under the same basic assumption used for the construction of a two-dimensional model. Namely, that the polarized growth of tubular cells (hyphoids) arises from a gradient of wall-building vesicles generated by a vesicle supply center (VSC). Contrary to the 2-D mathematical formulation, the three-dimensional derivation led to an indetermination whose solution required defining a priori the pattern of expansion of the wall, i.e. defining the overall spatial movement of the wall as the newly inserted wall elements displace the existing wall fabric. The patterns of wall expansion can be described by tracing the movement of marker points on the cell surface (point trajectories). Point trajectories were computed for three different modes of wall expansion of the VSC-generated hyphoids: orthogonal, isometric, and rotational. The 3-D VSC models allowed us to either stipulate or calculate the degree of anisotropy for each type of wall expansion. Wireframe models were built to visualize growth anisotropy in each model. Although the overall shape of the three hyphoid models is similar, they differ substantially in point trajectories and anisotropy. Point trajectories are experimentally testable and were the basis for the conclusion that hyphae grow in orthogonal fashion. (Bartnicki-Garcia et al., 2000. Biophys. J.79, 2382-2390.)

  20. Structure-preserving model reduction of large-scale logistics networks. Applications for supply chains

    Science.gov (United States)

    Scholz-Reiter, B.; Wirth, F.; Dashkovskiy, S.; Makuschewitz, T.; Schönlein, M.; Kosmykov, M.

    2011-12-01

    We investigate the problem of model reduction with a view to large-scale logistics networks, specifically supply chains. Such networks are modeled by means of graphs, which describe the structure of material flow. An aim of the proposed model reduction procedure is to preserve important features within the network. As a new methodology we introduce the LogRank as a measure for the importance of locations, which is based on the structure of the flows within the network. We argue that these properties reflect relative importance of locations. Based on the LogRank we identify subgraphs of the network that can be neglected or aggregated. The effect of this is discussed for a few motifs. Using this approach we present a meta algorithm for structure-preserving model reduction that can be adapted to different mathematical modeling frameworks. The capabilities of the approach are demonstrated with a test case, where a logistics network is modeled as a Jackson network, i.e., a particular type of queueing network.

  1. A strategic decision-making model considering the social costs of carbon dioxide emissions for sustainable supply chain management.

    Science.gov (United States)

    Tseng, Shih-Chang; Hung, Shiu-Wan

    2014-01-15

    Incorporating sustainability into supply chain management has become a critical issue driven by pressures from governments, customers, and various stakeholder groups over the past decade. This study proposes a strategic decision-making model considering both the operational costs and social costs caused by the carbon dioxide emissions from operating such a supply chain network for sustainable supply chain management. This model was used to evaluate carbon dioxide emissions and operational costs under different scenarios in an apparel manufacturing supply chain network. The results showed that the higher the social cost rate of carbon dioxide emissions, the lower the amount of the emission of carbon dioxide. The results also suggested that a legislation that forces the enterprises to bear the social costs of carbon dioxide emissions resulting from their economic activities is an effective approach to reducing carbon dioxide emissions.

  2. Understanding influential factors on implementing green supply chain management practices: An interpretive structural modelling analysis.

    Science.gov (United States)

    Agi, Maher A N; Nishant, Rohit

    2017-03-01

    In this study, we establish a set of 19 influential factors on the implementation of Green Supply Chain Management (GSCM) practices and analyse the interaction between these factors and their effect on the implementation of GSCM practices using the Interpretive Structural Modelling (ISM) method and the "Matrice d'Impacts Croisés Multiplication Appliquée à un Classement" (MICMAC) analysis on data compiled from interviews with supply chain (SC) executives based in the Gulf countries (Middle East region). The study reveals a strong influence and driving power of the nature of the relationships between SC partners on the implementation of GSCM practices. We especially found that dependence, trust, and durability of the relationship with SC partners have a very high influence. In addition, the size of the company, the top management commitment, the implementation of quality management and the employees training and education exert a critical influence on the implementation of GSCM practices. Contextual elements such as the industry sector and region and their effect on the prominence of specific factors are also highlighted through our study. Finally, implications for research and practice are discussed.

  3. Model for Determining the Optimum Location for Performance Improvement in Supply-Chain Strategies

    Directory of Open Access Journals (Sweden)

    Ramona Iulia ȚARȚAVULEA (DIEACONESCU

    2015-06-01

    Full Text Available The economic crisis which started in 2007 has caused damaging effects to most international companies. In several EU countries, foreign investments decreased and international companies closed or relocated production and/or distribution centres, due to cost reduction measures. This paper is aiming to demonstrate that applying a performant solution in defining the supply chain strategy can be a low cost process, which can generate positive effects on the sales and revenues. The research objective is to present a concrete solution for redesigning the supply chain, in order to achieve the optimal delivery strategy. The solution implies the use of mathematic methods, for determining the optimum location for placing a central warehouse, in a geographic region. The use of an optimum delivery strategy leads to lower depositing and transport costs, which generates positive effects on sales, by offering more competitive prices on products. The main contribution of the author is the development of a model, used to identify the optimal location for placing a central warehouse.

  4. Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

    African Journals Online (AJOL)

    Prof. Ogunji

    hydrocarbon polluted sediments and water .... ecosystem may result in selective increase or decrease in microbial population (Okpokwasili ... been implicated in degradation of hydrocarbons such as crude oil, polyaromatic hydrocarbons and.

  5. The Framework Model of Supply-Chain Process in CALS Environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    E-supply chain is the trend of the supply chain ma na gement. However, building E-supply chain depends on business process improvemen t and re-engineering, which becomes one of the important aspects in supply chai n management. However, the supply chain process re-engineering and improvement is constrained because of lack of integrating operation framework and standards based on information management. We find that the idea of CALS origins from DoD of USA can solve the problems very well. CALS is the abb...

  6. 3D modelling of a dolomitized syn-sedimentary structure: an exhumed potential analogue of hydrocarbon reservoir.

    Science.gov (United States)

    Martinelli, Mattia; Franceschi, Marco; Massironi, Matteo; Bistacchi, Andrea; Di Cuia, Raffaele; Rizzi, Alessandro

    2016-04-01

    further increase the potential creation of potential hydrocarbon traps. These complex conditions are visible in a syn-sedimentary structure spectacularly exposed on the Monte Testo (Trentino, Italy). In this contribution, we present a 3D geo-model of this structure, obtained with SKUA-gOcad, based on 3D photogrammetric modelling, detailed geological mapping and structural analysis, porosity analysis carried out on representative sections, and geostatistical simulation of porosity on dolomitized bodies. Thanks to the 3D model we obtained: i) a thickness map of the Rotzo Formation that allow us to understand which faults were active during the deposition of the formation and which areas could have been more suitable for hydrocarbon accumulation; ii) a geometric and volumetric model of the structure that permitted us to study the porosity distribution and to define the potential volume of hydrocarbons that could be hosted by a similar structure. These results were eventually extrapolated to the entire platform, providing clues on the hydrocarbon potential of similar buried geologic bodies.

  7. Economic Analysis in Restructured Electricity Supply Industry (ESI for Malaysian Market Model

    Directory of Open Access Journals (Sweden)

    Mohamad N.

    2016-01-01

    Full Text Available Before 1980s, the generation, transmission and distribution vertically related sectors have typically been tied together within a utility. It has been either, investor owned and state-regulated or owned by the local municipality. Each sector was thought of as a natural monopoly. During that era, there were two main reasons accelerated for restructuring needs. The first one was to widen up the choices of electricity for customers. And the second one was due to rapid expansion capacity needs in generation, transmission and distribution. In Malaysia, the Malaysian Electricity Supply Industry (MESI has aimed to restructure its current model to become a wholesale market model. In 1992, by introducing the Independent Power Producers (IPPs in the loop, MESI applies Single Buyer model. Single Buyer model is one of the existing models available under the restructuring apart from Pool and Bilateral. This paper evaluates the economic benefits for Malaysia with the current structure from the side of electricity provider. A case study with load variation for three different maximum demands is considered in this paper. The mathematical equation developed by zero Loss of Load Probability is applied to evaluate the economic benefits.

  8. Rigorous mathematical modelling for a Fast Corrector Power Supply in TPS

    Science.gov (United States)

    Liu, K.-B.; Liu, C.-Y.; Chien, Y.-C.; Wang, B.-S.; Wong, Y. S.

    2017-04-01

    To enhance the stability of beam orbit, a Fast Orbit Feedback System (FOFB) eliminating undesired disturbances was installed and tested in the 3rd generation synchrotron light source of Taiwan Photon Source (TPS) of National Synchrotron Radiation Research Center (NSRRC). The effectiveness of the FOFB greatly depends on the output performance of Fast Corrector Power Supply (FCPS); therefore, the design and implementation of an accurate FCPS is essential. A rigorous mathematical modelling is very useful to shorten design time and improve design performance of a FCPS. A rigorous mathematical modelling derived by the state-space averaging method for a FCPS in the FOFB of TPS composed of a full-bridge topology is therefore proposed in this paper. The MATLAB/SIMULINK software is used to construct the proposed mathematical modelling and to conduct the simulations of the FCPS. Simulations for the effects of the different resolutions of ADC on the output accuracy of the FCPS are investigated. A FCPS prototype is realized to demonstrate the effectiveness of the proposed rigorous mathematical modelling for the FCPS. Simulation and experimental results show that the proposed mathematical modelling is helpful for selecting the appropriate components to meet the accuracy requirements of a FCPS.

  9. Applying nonlinear MODM model to supply chain management with quantity discount policy under complex fuzzy environment

    Directory of Open Access Journals (Sweden)

    Zhe Zhang

    2014-06-01

    Full Text Available Purpose: The aim of this paper is to deal with the supply chain management (SCM with quantity discount policy under the complex fuzzy environment, which is characterized as the bi-fuzzy variables. By taking into account the strategy and the process of decision making, a bi-fuzzy nonlinear multiple objective decision making (MODM model is presented to solve the proposed problem.Design/methodology/approach: The bi-fuzzy variables in the MODM model are transformed into the trapezoidal fuzzy variables by the DMs's degree of optimism ?1 and ?2, which are de-fuzzified by the expected value index subsequently. For solving the complex nonlinear model, a multi-objective adaptive particle swarm optimization algorithm (MO-APSO is designed as the solution method.Findings: The proposed model and algorithm are applied to a typical example of SCM problem to illustrate the effectiveness. Based on the sensitivity analysis of the results, the bi-fuzzy nonlinear MODM SCM model is proved to be sensitive to the possibility level ?1.Practical implications: The study focuses on the SCM under complex fuzzy environment in SCM, which has a great practical significance. Therefore, the bi-fuzzy MODM model and MO-APSO can be further applied in SCM problem with quantity discount policy.Originality/value: The bi-fuzzy variable is employed in the nonlinear MODM model of SCM to characterize the hybrid uncertain environment, and this work is original. In addition, the hybrid crisp approach is proposed to transferred to model to an equivalent crisp one by the DMs's degree of optimism and the expected value index. Since the MODM model consider the bi-fuzzy environment and quantity discount policy, so this paper has a great practical significance.

  10. Prediction of cold start hydrocarbon emissions of air cooled two wheeler spark ignition engines by simple fuzzy logic simulation

    Directory of Open Access Journals (Sweden)

    Samuel Raja Ayyanan

    2014-01-01

    Full Text Available The cold start hydrocarbon emission from the increasing population of two wheelers in countries like India is one of the research issues to be addressed. This work describes the prediction of cold start hydrocarbon emissions from air cooled spark ignition engines through fuzzy logic technique. Hydrocarbon emissions were experimentally measured from test engines of different cubic capacity, at different lubricating oil temperature and at different idling speeds with and without secondary air supply in exhaust. The experimental data were used as input for modeling average hydrocarbon emissions for 180 seconds counted from cold start and warm start of gasoline bike engines. In fuzzy logic simulation, member functions were assigned for input variables (cubic capacity and idling rpm and output variables (average hydrocarbon emission for first 180 seconds at cold start and warm start. The knowledge based rules were adopted from the analyzed experimental data and separate simulations were carried out for predicting hydrocarbon emissions from engines equipped with and without secondary air supply. The simulation yielded the average hydrocarbon emissions of air cooled gasoline engine for a set of given input data with accuracy over 90%.

  11. Mathematical modeling for selecting center locations for medical and health supplies reserve in Hainan Province

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hua Hu; Chuan-Zhu Lu; Min Li; Cai-Hong Zhang; Hua Zhang

    2014-01-01

    Objective:To explore how to choose the center locations to build the medical and health supplies reserve among many island towns.Methods:The center locations were selected from18 towns HainanProvince, it’s maximum service range(distance) was required to reach the minimum, or to minimize.Results:Three scenarios were considered, the center locations included only one town, two towns, three towns.By the use of graph theory andMATLAB programming, a mathematical model was established to obtain the shortest distance and the shortest path between arbitrary two towns.Conclusions:We find out the center sites under certain conditions, and determine the specific service ranges of the center sites.

  12. Using fuzzy cognitive maps to model performance measurement system of Internet-based supply chain

    Institute of Scientific and Technical Information of China (English)

    CHEN Juan-juan; WANG Cheng-liang

    2006-01-01

    Fuzzy cognitive maps (FCM) is a well-established artificial intelligence technique, which can be effectively applied in the domains of performance measurement, decision making and other management science. FCM can be a useful tool in a group decision-making environment by using scientifically integrated expert knowledge. The theories of FCM and balance scorecard (BSC) both emphasize cause-and-effect relationships among indicators in a complex system, but few reports have been published addressing the combined application of these two techniques. In this paper we propose a FCM simulation model for the sample performance measurement system of Internet-based supply chain, which is constructed by BSC theory.We gave examples to explain how FCM can be adapted to execute the causal mechanism of BSC, and also how FCM can support group decision-making and forecasting in performance measurement.

  13. Supply Chain Vulnerability Analysis Using Scenario-Based Input-Output Modeling: Application to Port Operations.

    Science.gov (United States)

    Thekdi, Shital A; Santos, Joost R

    2016-05-01

    Disruptive events such as natural disasters, loss or reduction of resources, work stoppages, and emergent conditions have potential to propagate economic losses across trade networks. In particular, disruptions to the operation of container port activity can be detrimental for international trade and commerce. Risk assessment should anticipate the impact of port operation disruptions with consideration of how priorities change due to uncertain scenarios and guide investments that are effective and feasible for implementation. Priorities for protective measures and continuity of operations planning must consider the economic impact of such disruptions across a variety of scenarios. This article introduces new performance metrics to characterize resiliency in interdependency modeling and also integrates scenario-based methods to measure economic sensitivity to sudden-onset disruptions. The methods will be demonstrated on a U.S. port responsible for handling $36.1 billion of cargo annually. The methods will be useful to port management, private industry supply chain planning, and transportation infrastructure management.

  14. Modeling and performance analysis of a closed-loop supply chain using first-order hybrid Petri nets

    Directory of Open Access Journals (Sweden)

    Imane Outmal

    2016-05-01

    Full Text Available Green or closed-loop supply chain had been the focus of many manufacturers during the last decade. The application of closed-loop supply chain in today’s manufacturing is not only due to growing environmental concerns and the recognition of its benefits in reducing greenhouse gas emissions, energy consumption, and meeting a more strict environmental regulations but it also offers economic competitive advantages if appropriately managed. First-order hybrid Petri nets represent a powerful graphical and mathematical formalism to map and analyze the dynamics of complex systems such as closed-loop supply chain networks. This article aims at illustrating the use of first-order hybrid Petri nets to model a closed-loop supply chain network and evaluate its operational, financial, and environmental performance measures under different management policies. Actual data from auto manufacturer in the United States are used to validate network’s performance under both tactical and strategic decision-making, namely, (1 tactical decision—production policies: increase of recovered versus new components and (2 strategic decision—closed-loop supply chain network structure: manufacturer internal recovery process or recovery process done by a third-party collection and recovery center. The work presented in this article is an extension of the use of first-order hybrid Petri nets as a modeling and performance analysis tool from supply chain to closed-loop supply chain. The modularity property of first-order hybrid Petri nets has been used in the modeling process, and the simulation and analysis of the modeled network are done in MATLAB® environment. The results of the experiments depict that first-order hybrid Petri nets are a powerful modeling and analysis formalism for closed-loop supply chain networks and can be further used as an efficient decision-making tool at both tactical and strategic levels. Unlike other researches on modeling supply chain

  15. Assessing adsorption of polycyclic aromatic hydrocarbons on Rhizopus oryzae cell wall components with water-methanol cosolvent model.

    Science.gov (United States)

    Ma, Bin; Lv, Xiaofei; He, Yan; Xu, Jianming

    2016-03-01

    The contribution of different fungal cell wall components in adsorption of polycyclic aromatic hydrocarbons (PAHs) is still unclear. We isolated Rhizopus oryzae cell walls components with sequential extraction, characterized functional groups with NEXAFS spectra, and determined partition coefficients of PAHs on cell walls and cell wall components with cosolvent model. Spectra of NEXAFS indicated that isolated cell walls components were featured with peaks at ~532.7 and ~534.5eV energy. The lipid cosolvent partition coefficients were approximately one order of magnitude higher than the corresponding carbohydrate cosolvent partition coefficients. The partition coefficients for four tested carbohydrates varied at approximate 0.5 logarithmic units. Partition coefficients between biosorbents and water calculated based cosolvent models ranged from 0.8 to 4.2. The present study proved the importance of fungal cell wall components in adsorption of PAHs, and consequently the role of fungi in PAHs bioremediation.

  16. A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Curran, H J

    2005-11-14

    A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.

  17. A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Curran, H J

    2005-11-14

    A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.

  18. Modeling Relief Demands in an Emergency Supply Chain System under Large-Scale Disasters Based on a Queuing Network

    Science.gov (United States)

    He, Xinhua

    2014-01-01

    This paper presents a multiple-rescue model for an emergency supply chain system under uncertainties in large-scale affected area of disasters. The proposed methodology takes into consideration that the rescue demands caused by a large-scale disaster are scattered in several locations; the servers are arranged in multiple echelons (resource depots, distribution centers, and rescue center sites) located in different places but are coordinated within one emergency supply chain system; depending on the types of rescue demands, one or more distinct servers dispatch emergency resources in different vehicle routes, and emergency rescue services queue in multiple rescue-demand locations. This emergency system is modeled as a minimal queuing response time model of location and allocation. A solution to this complex mathematical problem is developed based on genetic algorithm. Finally, a case study of an emergency supply chain system operating in Shanghai is discussed. The results demonstrate the robustness and applicability of the proposed model. PMID:24688367

  19. Modeling relief demands in an emergency supply chain system under large-scale disasters based on a queuing network.

    Science.gov (United States)

    He, Xinhua; Hu, Wenfa

    2014-01-01

    This paper presents a multiple-rescue model for an emergency supply chain system under uncertainties in large-scale affected area of disasters. The proposed methodology takes into consideration that the rescue demands caused by a large-scale disaster are scattered in several locations; the servers are arranged in multiple echelons (resource depots, distribution centers, and rescue center sites) located in different places but are coordinated within one emergency supply chain system; depending on the types of rescue demands, one or more distinct servers dispatch emergency resources in different vehicle routes, and emergency rescue services queue in multiple rescue-demand locations. This emergency system is modeled as a minimal queuing response time model of location and allocation. A solution to this complex mathematical problem is developed based on genetic algorithm. Finally, a case study of an emergency supply chain system operating in Shanghai is discussed. The results demonstrate the robustness and applicability of the proposed model.

  20. Modeling Relief Demands in an Emergency Supply Chain System under Large-Scale Disasters Based on a Queuing Network

    Directory of Open Access Journals (Sweden)

    Xinhua He

    2014-01-01

    Full Text Available This paper presents a multiple-rescue model for an emergency supply chain system under uncertainties in large-scale affected area of disasters. The proposed methodology takes into consideration that the rescue demands caused by a large-scale disaster are scattered in several locations; the servers are arranged in multiple echelons (resource depots, distribution centers, and rescue center sites located in different places but are coordinated within one emergency supply chain system; depending on the types of rescue demands, one or more distinct servers dispatch emergency resources in different vehicle routes, and emergency rescue services queue in multiple rescue-demand locations. This emergency system is modeled as a minimal queuing response time model of location and allocation. A solution to this complex mathematical problem is developed based on genetic algorithm. Finally, a case study of an emergency supply chain system operating in Shanghai is discussed. The results demonstrate the robustness and applicability of the proposed model.