Quantities of natural gas transmitted in January-December 2012. Quantities of natural gas transported in January-December 2012

International Nuclear Information System (INIS)

2013-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2012: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

Measurement of gas transport properties for chemical vapor infiltration

Energy Technology Data Exchange (ETDEWEB)

Starr, T.L.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

1996-12-01

In the chemical vapor infiltration (CVI) process for fabricating ceramic matrix composites (CMCs), transport of gas phase reactant into the fiber preform is a critical step. The transport can be driven by pressure or by concentration. This report describes methods for measuring this for CVI preforms and partially infiltrated composites. Results are presented for Nicalon fiber cloth layup preforms and composites, Nextel fiber braid preforms and composites, and a Nicalon fiber 3-D weave composite. The results are consistent with a percolating network model for gas transport in CVI preforms and composites. This model predicts inherent variability in local pore characteristics and transport properties, and therefore, in local densification during processing; this may lead to production of gastight composites.

Requirements for gas quality and gas appliances

NARCIS (Netherlands)

Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

2015-01-01

Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

Spatial and intertemporal arbitrage in the California natural gas transportation and storage network

Science.gov (United States)

Uria Martinez, Rocio

Intertemporal and spatial price differentials should provide the necessary signals to allocate a commodity efficiently inside a network. This dissertation investigates the extent to which decisions in the California natural gas transportation and storage system are taken with an eye on arbitrage opportunities. Daily data about flows into and out of storage facilities in California over 2002-2006 and daily spreads on the NYMEX futures market are used to investigate whether the injection profile is consistent with the "supply-of-storage" curve first observed by Working for wheat. Spatial price differentials between California and producing regions fluctuate throughout the year, even though spot prices at trading hubs across North America are highly correlated. In an analysis of "residual supply", gas volumes directed to California are examined for the influence of those fluctuations in locational differentials. Daily storage decisions in California do seem to be influenced by a daily price signal that combines the intertemporal spread and the locational basis between California and the Henry Hub, in addition to strong seasonal and weekly cycles. The timing and magnitude of the response differs across storage facilities depending on the regulatory requirements they face and the type of customers they serve. In contrast, deviations in spatial price differentials from the levels dictated by relative seasonality in California versus competing regions do not trigger significant reallocations of flows into California. Available data for estimation of both the supply-of-storage and residual-supply curves aggregate the behavior of many individuals whose motivations and attentiveness to prices vary. The resulting inventory and flow profiles differ from those that a social planner would choose to minimize operating costs throughout the network. Such optimal allocation is deduced from a quadratic programming model, calibrated to 2004-2005, that acknowledges relative seasonality

Report of the experts group on the taxation of the access to gas transport and distribution network; Rapport du groupe d'experts sur la tarification de l'acces aux reseaux de transport et de distribution de gaz

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-04-01

In the framework of a new french gas industry organization (directive of the 22 june 1998), a concerting mission has been realized on prices taxation for the transport and distribution facilities. The following topics have been debated: the integration and competition of the european gas market, the gas market liberalization consistency and the taxation of transport and distribution network access. (A.L.B.)

Proposition of the CRE for the tariffs concerning the use of natural gas transportation networks

International Nuclear Information System (INIS)

2003-01-01

The national transportation network involves: the main network constituted by the transportation works binding the access and exit points of the national territory and the underground storages; the regional network for the regional distribution upstream of the main network. The chosen tariff model is a in-out type. Each tariff includes the access terms on the main network, the exit terms of the main network, sometimes the binding terms between the equilibrium zones, the transportation terms on the regional network and the delivery terms. (A.L.B.)

Neutral gas transport modeling with DEGAS 2

International Nuclear Information System (INIS)

Karney, C.; Stotler, D.

1993-01-01

The authors are currently re-writing the neutral gas transport code, DEGAS, with a view to making it both faster and easier to include new physics. They present model calculations including ionization and charge exchange illustrating the way that reactions are included into DEGAS 2 and its operation on a distributed network of workstations

Natural gas marketing and transportation

International Nuclear Information System (INIS)

Anon.

1991-01-01

This book covers: Overview of the natural gas industry; Federal regulation of marketing and transportation; State regulation of transportation; Fundamentals of gas marketing contracts; Gas marketing options and strategies; End user agreements; Transportation on interstate pipelines; Administration of natural gas contracts; Structuring transactions with the nonconventional source fuels credit; Take-or-pay wars- a cautionary analysis for the future; Antitrust pitfalls in the natural gas industry; Producer imbalances; Natural gas futures for the complete novice; State non-utility regulation of production, transportation and marketing; Natural gas processing agreements and Disproportionate sales, gas balancing, and accounting to royalty owners

Animal transportation networks

Science.gov (United States)

Perna, Andrea; Latty, Tanya

2014-01-01

Many group-living animals construct transportation networks of trails, galleries and burrows by modifying the environment to facilitate faster, safer or more efficient movement. Animal transportation networks can have direct influences on the fitness of individuals, whereas the shape and structure of transportation networks can influence community dynamics by facilitating contacts between different individuals and species. In this review, we discuss three key areas in the study of animal transportation networks: the topological properties of networks, network morphogenesis and growth, and the behaviour of network users. We present a brief primer on elements of network theory, and then discuss the different ways in which animal groups deal with the fundamental trade-off between the competing network properties of travel efficiency, robustness and infrastructure cost. We consider how the behaviour of network users can impact network efficiency, and call for studies that integrate both network topology and user behaviour. We finish with a prospectus for future research. PMID:25165598

Gas fuels for the transport sector; Denmark; Gas til transportsektoren

Energy Technology Data Exchange (ETDEWEB)

2012-07-01

Recent analyses suggest that especially biogas, but also natural gas in macroeconomic terms will be attractive propellants, including for heavy transport. To implement a Danish expansion of gas infrastructure for transportation, the report recommends the following essential elements: 1) A Danish rollout should be closely linked to contracts with fleet owners with heavy vehicles / taxis / vans and the like, thus ensuring high utilization of filling stations; 2) About 10 larger, flexible CNG filling stations set up at major fleet owners is estimated as sufficient for an initial deployment phase, strategically distributed in and around Copenhagen, the major cities and along the main road network from Sweden to Germany; 3) A certain time-limited funding for the construction of infrastructure is likely to cause a rapid spread, if desired, and if other business conditions are in place; 4) There is a need for adjustment of tax terms - the rules for green taxes should be adjusted, and it should be considered to lower the taxes on CNG and biogas; 5) Natural gas mixed with biogas should be an integral element of a comprehensive strategy to ensure maximum CO{sub 2} displacement. (LN)

Applications of ZigBee Technology in the Safety Monitoring System of Low Gas Pipeline Transportation

Directory of Open Access Journals (Sweden)

Wei Deyu

2015-01-01

Full Text Available The existing safety monitoring system of low gas pipeline transportation establishes a wired communication network monitoring system mainly on the basis of industrial bus. It has problems such as large transmission signal attenuation, complex wiring, high-labor intensity, inconvenient installation and maintenance, high maintenance cost, and so on. Featuring low cost, power-saving, reliability, stability and flexibility, the wireless sensor network established by ZigBee wireless communication technology can realize the real-time all-dimensional dynamic monitoring on parameters of low gas pipeline transportation system and overcome the shortcomings and deficiencies of wired network system.

Thinking on Sichuan-Chongqing gas pipeline transportation system reform under market-oriented conditions

Science.gov (United States)

Duan, Yanzhi

2017-01-01

The gas pipeline networks in Sichuan and Chongqing (Sichuan-Chongqing) region have formed a fully-fledged gas pipeline transportation system in China, which supports and promotes the rapid development of gas market in Sichuan-Chongqing region. In the circumstances of further developed market-oriented economy, it is necessary to carry out further the pipeline system reform in the areas of investment/financing system, operation system and pricing system to lay a solid foundation for improving future gas production and marketing capability and adapting itself to the national gas system reform, and to achieve the objectives of multiparty participated pipeline construction, improved pipeline transportation efficiency and fair and rational pipeline transportation prices. In this article, main thinking on reform in the three areas and major deployment are addressed, and corresponding measures on developing shared pipeline economy, providing financial support to pipeline construction, setting up independent regulatory agency to enhance the industrial supervision for gas pipeline transportation, and promoting the construction of regional gas trade market are recommended.

The shipper as the architect of contractual relations in access to natural gas networks

International Nuclear Information System (INIS)

Codognet, Marc-Kevin

2005-01-01

Transportation and contractual arrangements are in the kernel of the natural gas reform in Europe. Since third party can access to pipelines, those who wish to ship gas between two locations of a gas network have to arrange transportation services. Natural gas transportation is a set of contractual arrangements and has become a complex contracting process. This paper aims at analyzing the typical economic functions of shippers in third-party access regimes in the natural gas industry in a transaction costs approach. Shippers provide and combine intermediation functions in transportation services markets: information management, matching, bundling and transactions guarantees. In this context, the shipper has appeared as a particular market intermediary specialized in transportation arrangements in the new regime of third party access in the natural gas industry. (Author)

The redefinition of the american and british gas industries: the regulation of the access load to the gas pipelines networks

International Nuclear Information System (INIS)

David, L.

2000-10-01

The transport and distribution networks regulation is the main stakes of the regulation reform of the gas industries. This thesis analyzes the models applied in The Usa and in the United Kingdom. The first part deals with the gas industries deregulation in these two countries, the impacts on the economy and the organization of the gas industries. The second part presents a theoretical approach of the regulation applied to the prices of the natural ags transport by gas pipelines. Regulation by the service cost price and by price cap are compared. (A.L.B.)

Strategic regulation of gas transport

International Nuclear Information System (INIS)

Nese, Gjermund; Straume, Odd Rune

2005-01-01

The basis of the article has been the steadily increasing focus particularly from EU, on increased competition in the natural gas markets. This could influence the profit distribution between the gas producing and consuming counties which is an important problem situation for Norway as a gas producer. The gas market value chain consist of three parts (production, transport and distribution). How the countries may use strategic regulation of the transport tariff for the transport and distribution systems in order to move as much as possible of the total profit to the part of the value chain in control is studied. The focus has been on how increased competition influences the incentives of the authorities through low or high transport tariff and to what extent increased competition influences the welfare level in the producer and consumer counties when strategic regulations of the transport occur. The analysis is based on a theoretical model developed in 2005. Some central mechanisms related to the natural gas market are mapped and Norway may counteract some negative effects of liberalisation of the European gas market through strategic adaptation of the transport tariff to the Norwegian gas transport systems

Impact of transition to a low carbon power system on the GB gas network

International Nuclear Information System (INIS)

Qadrdan, Meysam; Chaudry, Modassar; Jenkins, Nick; Baruah, Pranab; Eyre, Nick

2015-01-01

Highlights: • Availability and cost of gas are crucial factors in power system planning. • CGEN+ was developed to analyse expansion of combined gas and electricity systems. • Performance of various low carbon strategies were assessed. • Electrification of heat and transport requires large investment in power sector. • Despite declining demand for gas, peak gas demand will almost remain unchanged. - Abstract: The reliance of Great Britain power generation on the gas network makes it critical to consider the future availability and cost of gas in planning the expansion of the power system. A combined gas and electricity network planning model was used to investigate impacts of various low carbon strategies on regional expansion of the Great Britain gas network out to the 2050s. A number of long term energy supply and demand strategies covering a range of plausible investment policies for Great Britain gas and electricity systems were explored. Reliance of Great Britain on gas imports was projected to vary from 84%, in an energy system with significant electrification of heat and transport sectors and large capacity of nuclear generation, to 94% in a business as usual case. Extensive investment in Liquefied Natural Gas import facilities at Milford Haven and the Isle of Grain was shown to compensate for reduction of indigenous gas supplies. Exploitation of shale gas in north England was shown to reduce the gas dependency of Great Britain in the business as usual case to 74%. Electrification of the heat and transport sectors combined with exploitation of shale gas in Great Britain could reduce import dependency to below 10% by 2050

Competing Transport Networks

NARCIS (Netherlands)

M.J. van der Leij (Marco)

2003-01-01

textabstractIn a circular city model, I consider network design and pricing decisions for a single fast transport connection that faces competition from a slower but better accessible transport mode. To access the fast transport network individuals have to make complementary trips by slow mode. This

Logistic management system for natural gas transportation by pipelines; Sistema de gestao de logistica de transporte de gas por gasodutos

Energy Technology Data Exchange (ETDEWEB)

Santos, Sidney Pereira dos; Castro, Antonio Orestes de Salvo [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Leal, Jose Eugenio [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

2008-07-01

An efficient management of the natural gas business chain, based on pipeline transmission network and taking into consideration the interaction between the main players such as shippers, suppliers, transmission companies and local distribution companies, requires the use of decision-making support systems to maximize resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages as well as market demand shortfalls. This work presents a practical utilization of technologies such as thermohydraulic simulation of gas flow through pipelines, Monte Carlo simulation for compressor station availability studies and economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for maximization and minimization objective function. The proposed system allows the definition of the optimum availability level to be maintained by the Transporter, by means of installing redundancy, to mitigate losses related to revenue and contractual penalties. Identifies, quantifies and justifies economically the installation of stand-by compressor units, mitigating Transporter exposure to losses due to capacity shortfalls as consequence of scheduled and non-scheduled outages. (author)

A risk analysis for gas transport network planning expansion under regulatory uncertainty in Western Europe

NARCIS (Netherlands)

Pelletier, 27736; Wortmann, J.C.; Noteboom, H.J.

The natural gas industry in Western Europe went through drastic changes induced by the unbundling of the national companies, followed by the liberalization of gas trade and the regulation of gas transmission. Natural gas transmission is operated through a network of interconnected grids, and is

Expert System for support of natural gas network management; Sistema especialista para gerenciamento de redes de gas natural: SEGRED

Energy Technology Data Exchange (ETDEWEB)

Silva, Jonny Carlos da [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Hirano, Eduardo Wulff [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Lab. de Hidraulica e Pneumatica (LASHIP); Moura, Newton Reis de [PETROBRAS, Rio de Janeiro, RJ (Brazil); Freire, Luiz Gustavo de Melo [PETROBRAS S.A., Pojuca, BA (Brazil). Unidade de Negocios de Gas Natural (UNGN)

2004-07-01

This work reports on the SEGRED project, which aims to develop an expert system for management of natural gas transportation networks. The system is currently being developed by LASHIP-UFSC in partnership with PETROBRAS/CENPES and TBG. The SEGRED system consists of an environment designed to support natural gas pipeline management by means of remote supervision of process parameters and analysis of the mutual interactions of those parameters by an expert system integrated to a dynamic simulator. The system is deployed through a process that contributes to making available for use the knowledge about functions such as line packing analysis and line break detection, thus enhancing the quality of execution of these tasks, which are related to the management of natural gas transportation network. The main benefits consist of promoting efforts to acquire and organize expert knowledge. This process contributes to the generation of a knowledge base with corporate technical memory, which can be made available in a permanent, expansible and useful way for decision-making. (author)

Network design for cylinder gas distribution

Directory of Open Access Journals (Sweden)

Tejinder Pal Singh

2015-01-01

Full Text Available Purpose: Network design of the supply chain is an important and strategic aspect of logistics management. In this paper, we address the network design problem specific to packaged gases (cylinder supply chain. We propose an integrated framework that allows for the determination of the optimal facility locations, the filling plant production capacities, the inventory at plants and hubs, and the number of packages to be routed in primary and secondary transportation. Design/methodology/approach: We formulate the problem as a mixed integer program and then develop a decomposition approach to solve it. We illustrate the proposed framework with numerical examples from real-life packaged gases supply chain. The results show that the decomposition approach is effective in solving a broad range of problem sizes. Findings: The main finding of this paper is that decomposing the network design problem into two sub-problems is very effective to tackle the real-life large scale network design problems occurring in cylinder gas distribution by optimizing strategic and tactical decisions and approximating the operational decisions. We also benchmark the results from the decomposition approach by solving the complete packaged gases network design model for smaller test cases. Originality/value: The main contribution of our work is that it integrates supply chain network design decisions without fixing the fillings plant locations with inventory and resource allocation decisions required at the plants. We also consider the transportation costs for the entire supply chain including the transhipment costs among different facilities by deciding the replenishment frequency.

Transportation Network Topologies

Science.gov (United States)

Holmes, Bruce J.; Scott, John

2004-01-01

A discomforting reality has materialized on the transportation scene: our existing air and ground infrastructures will not scale to meet our nation's 21st century demands and expectations for mobility, commerce, safety, and security. The consequence of inaction is diminished quality of life and economic opportunity in the 21st century. Clearly, new thinking is required for transportation that can scale to meet to the realities of a networked, knowledge-based economy in which the value of time is a new coin of the realm. This paper proposes a framework, or topology, for thinking about the problem of scalability of the system of networks that comprise the aviation system. This framework highlights the role of integrated communication-navigation-surveillance systems in enabling scalability of future air transportation networks. Scalability, in this vein, is a goal of the recently formed Joint Planning and Development Office for the Next Generation Air Transportation System. New foundations for 21st thinking about air transportation are underpinned by several technological developments in the traditional aircraft disciplines as well as in communication, navigation, surveillance and information systems. Complexity science and modern network theory give rise to one of the technological developments of importance. Scale-free (i.e., scalable) networks represent a promising concept space for modeling airspace system architectures, and for assessing network performance in terms of scalability, efficiency, robustness, resilience, and other metrics. The paper offers an air transportation system topology as framework for transportation system innovation. Successful outcomes of innovation in air transportation could lay the foundations for new paradigms for aircraft and their operating capabilities, air transportation system architectures, and airspace architectures and procedural concepts. The topology proposed considers air transportation as a system of networks, within which

Dynamic safety assessment of natural gas stations using Bayesian network

Energy Technology Data Exchange (ETDEWEB)

Zarei, Esmaeil, E-mail: smlzarei65@gmail.com [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Azadeh, Ali [School of Industrial and Systems Engineering, Center of Excellence for Intelligent-Based Experimental Mechanic, College of Engineering, University of Tehran (Iran, Islamic Republic of); Khakzad, Nima [Safety and Security Science Section, Delft University of Technology, Delft (Netherlands); Aliabadi, Mostafa Mirzaei [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Mohammadfam, Iraj, E-mail: mohammadfam@umsha.ac.ir [Center of Excellence for Occupational Health Engineering, Research Center for Health Sciences, Faculty of Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of)

2017-01-05

Graphical abstract: Dynamic cause-consequence analysis of the regulator system failure using BN. - Highlights: • A dynamic and comprehensive QRA (DCQRA) framework is proposed for safety assessment of CGSs. • Bow-tie diagram and Bayesian network are employed for accident scenario modeling. • Critical basic events and minimal cut sets are identified using probability updating. - Abstract: Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations. In this approach, a FMEA is used for hazard analysis while a Bow-tie diagram and Bayesian network are employed to model the worst-case accident scenario and to assess the risks. The results have indicated that the failure of the regulator system was the worst-case accident scenario with the human error as the most contributing factor. Thus, in risk management plan of natural gas stations, priority should be given to the most probable root events and main contribution factors, which have identified in the present study, in order to reduce the occurrence probability of the accident scenarios and thus alleviate the risks.

Dynamic safety assessment of natural gas stations using Bayesian network

International Nuclear Information System (INIS)

Zarei, Esmaeil; Azadeh, Ali; Khakzad, Nima; Aliabadi, Mostafa Mirzaei; Mohammadfam, Iraj

2017-01-01

Graphical abstract: Dynamic cause-consequence analysis of the regulator system failure using BN. - Highlights: • A dynamic and comprehensive QRA (DCQRA) framework is proposed for safety assessment of CGSs. • Bow-tie diagram and Bayesian network are employed for accident scenario modeling. • Critical basic events and minimal cut sets are identified using probability updating. - Abstract: Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations. In this approach, a FMEA is used for hazard analysis while a Bow-tie diagram and Bayesian network are employed to model the worst-case accident scenario and to assess the risks. The results have indicated that the failure of the regulator system was the worst-case accident scenario with the human error as the most contributing factor. Thus, in risk management plan of natural gas stations, priority should be given to the most probable root events and main contribution factors, which have identified in the present study, in order to reduce the occurrence probability of the accident scenarios and thus alleviate the risks.

Transport Insight 2009. An annual behind-the-scenes view in North West European gas transmission

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-09-15

Transport Insight provides the users of the gas network, customers (shippers) and other stakeholders with clear and coherent information every year, directly from the source; the Transmission System Operators. TSOs Gas Transport Services (GTS) and Gasunie Deutschland (GUD) have worked closely together to present Transport Insight 2009 as a joint publication. Section 1 describes the major developments and circumstances that affected the gas transmission system in 2008. Section 2 gives in-depth analyses of actual gas transmission at the border clusters of the Gas Transport Services and Gasunie Deutschland grids. These are illustrated in graphs by means of key figures from 2008 and show details of availability, contracted capacity and usage. Section 3 considers trends in Europe, specifically looking at the production decline and swing decline. These sections are followed by the themes in section 4. In these themes a specific topic is discussed in more detail. The first theme describes developments concerning the Title Transfer Facility (TTF) and the Virtual Trading Place (VHP). The second theme focuses on trends in gas storage in Europe.

Transport Insight 2009. An annual behind-the-scenes view in North West European gas transmission

International Nuclear Information System (INIS)

2009-09-01

Transport Insight provides the users of the gas network, customers (shippers) and other stakeholders with clear and coherent information every year, directly from the source; the Transmission System Operators. TSOs Gas Transport Services (GTS) and Gasunie Deutschland (GUD) have worked closely together to present Transport Insight 2009 as a joint publication. Section 1 describes the major developments and circumstances that affected the gas transmission system in 2008. Section 2 gives in-depth analyses of actual gas transmission at the border clusters of the Gas Transport Services and Gasunie Deutschland grids. These are illustrated in graphs by means of key figures from 2008 and show details of availability, contracted capacity and usage. Section 3 considers trends in Europe, specifically looking at the production decline and swing decline. These sections are followed by the themes in section 4. In these themes a specific topic is discussed in more detail. The first theme describes developments concerning the Title Transfer Facility (TTF) and the Virtual Trading Place (VHP). The second theme focuses on trends in gas storage in Europe.

Gas transport in porous media

CERN Document Server

Ho, Clifford K

2006-01-01

This book presents a compilation of state-of-the art studies on gas and vapor transport processes in porous and fractured media. A broad set of models and processes are presented, including advection/diffusion, the Dusty Gas Model, enhanced vapor diffusion, phase change, coupled processes, solid/vapor sorption, and vapor-pressure lowering. Numerous applications are also presented that illustrate these processes and models in current problems facing the scientific community. This book fills a gap in the general area of transport in porous and fractured media; an area that has historically been dominated by studies of liquid-phase flow and transport. This book identifies gas and vapor transport processes that may be important or dominant in various applications, and it exploits recent advances in computational modeling and experimental methods to present studies that distinguish the relative importance of various mechanisms of transport in complex media.

The petroleum, natural gas and bio fuel transportation; O transporte de petroleo, gas natural e biocombustiveis

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Diego Varela; Campos, Carlos Hebert

2011-01-15

The paper expose on the activity of petroleum, natural gas and bio fuels transportation, outlining the transportation means used by the petroleum industry. After that, analyses the importance and the economic relevance of the Transpetro. Yet, proceeds an examination of the transportation activity under a constitutional optics, based on the EC 9/95; a legal optic, from the Petroleum Law (Law 9478/97) and some other legal documents related to the theme. Finally, presents the importance that the Law of Natural Gas (Law 11909/09) brought for that activity, by making possible that the natural gas transportation can also be effectuated through the Concession.

The future of the UK gas network

International Nuclear Information System (INIS)

Dodds, Paul E.; McDowall, Will

2013-01-01

The UK has an extensive natural gas pipeline network supplying 84% of homes. Previous studies of decarbonisation pathways using the UK MARKAL energy system model have concluded that the low-pressure gas networks should be mostly abandoned by 2050, yet most of the iron pipes near buildings are currently being replaced early for safety reasons. Our study suggests that this programme will not lock-in the use of gas in the long-term. We examine potential future uses of the gas network in the UK energy system using an improved version of UK MARKAL that introduces a number of decarbonisation options for the gas network including bio-methane, hydrogen injection to the natural gas and conversion of the network to deliver hydrogen. We conclude that hydrogen conversion is the only gas decarbonisation option that might enable the gas networks to continue supplying energy to most buildings in the long-term, from a cost-optimal perspective. There is an opportunity for the government to adopt a long-term strategy for the gas distribution networks that either curtails the iron mains replacement programme or alters it to prepare the network for hydrogen conversion; both options could substantially reduce the long-term cost of supplying heat to UK buildings. - Highlights: • We examine the long-term future of the UK gas pipe networks using the UK MARKAL model. • The iron mains replacement programme will not lead to gas infrastructure lock-in. • Bio-methane and hydrogen injection have only a small role in our future scenarios. • The most cost-optimal strategy might be to convert the networks to deliver hydrogen. • Adopting a long-term gas strategy could reduce the cost of providing heat in the UK

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo

2015-09-15

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.

Quantitative Efficiency Evaluation Method for Transportation Networks

Directory of Open Access Journals (Sweden)

Jin Qin

2014-11-01

Full Text Available An effective evaluation of transportation network efficiency/performance is essential to the establishment of sustainable development in any transportation system. Based on a redefinition of transportation network efficiency, a quantitative efficiency evaluation method for transportation network is proposed, which could reflect the effects of network structure, traffic demands, travel choice, and travel costs on network efficiency. Furthermore, the efficiency-oriented importance measure for network components is presented, which can be used to help engineers identify the critical nodes and links in the network. The numerical examples show that, compared with existing efficiency evaluation methods, the network efficiency value calculated by the method proposed in this paper can portray the real operation situation of the transportation network as well as the effects of main factors on network efficiency. We also find that the network efficiency and the importance values of the network components both are functions of demands and network structure in the transportation network.

Optimal transport on supply-demand networks.

Science.gov (United States)

Chen, Yu-Han; Wang, Bing-Hong; Zhao, Li-Chao; Zhou, Changsong; Zhou, Tao

2010-06-01

In the literature, transport networks are usually treated as homogeneous networks, that is, every node has the same function, simultaneously providing and requiring resources. However, some real networks, such as power grids and supply chain networks, show a far different scenario in which nodes are classified into two categories: supply nodes provide some kinds of services, while demand nodes require them. In this paper, we propose a general transport model for these supply-demand networks, associated with a criterion to quantify their transport capacities. In a supply-demand network with heterogeneous degree distribution, its transport capacity strongly depends on the locations of supply nodes. We therefore design a simulated annealing algorithm to find the near optimal configuration of supply nodes, which remarkably enhances the transport capacity compared with a random configuration and outperforms the degree target algorithm, the betweenness target algorithm, and the greedy method. This work provides a start point for systematically analyzing and optimizing transport dynamics on supply-demand networks.

Scaling in public transport networks

Directory of Open Access Journals (Sweden)

C. von Ferber

2005-01-01

Full Text Available We analyse the statistical properties of public transport networks. These networks are defined by a set of public transport routes (bus lines and the stations serviced by these. For larger networks these appear to possess a scale-free structure, as it is demonstrated e.g. by the Zipf law distribution of the number of routes servicing a given station or for the distribution of the number of stations which can be visited from a chosen one without changing the means of transport. Moreover, a rather particular feature of the public transport network is that many routes service common subsets of stations. We discuss the possibility of new scaling laws that govern intrinsic properties of such subsets.

Trans Ocean Gas CNG transportation development plan

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-11-01

Liquefied natural gas (LNG) transportation is on the rise due to increased global demand for natural gas. However, the challenge of transporting LNG lies in finding suitable locations for import terminals. Compressed natural gas (CNG) transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets not practical for LNG or pipelines. The founder of Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. Financial support is needed to perform verification testing and for regulatory approval. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. 2 tabs., 3 figs.

Investment in transport infrastructure, regulation, and gas-gas competition

Energy Technology Data Exchange (ETDEWEB)

Gasmi, Farid [Toulouse School of Economics (ARQADE and IDEI), Universite Toulouse 1 Capitole (France); Oviedo, Juan Daniel [Universidad del Rosario (Colombia)

2010-05-15

This paper develops a simple model in which a regulated (upstream) transporter provides capacity to a marketer competing in output with an incumbent in the (downstream) gas commodity market. The equilibrium outcome of the firms' interaction in the downstream market is explicitly taken into account by the regulator when setting the transport charge. We consider various forms of competition in this market and derive the corresponding optimal transport charge policies. We then run simulations that allow us to perform a comparative welfare analysis of these transport infrastructure investment policies based on different assumptions about the intensity of the competition that prevails in the gas commodity market. (author)

Investment in transport infrastructure, regulation, and gas-gas competition

International Nuclear Information System (INIS)

Gasmi, Farid; Oviedo, Juan Daniel

2010-01-01

This paper develops a simple model in which a regulated (upstream) transporter provides capacity to a marketer competing in output with an incumbent in the (downstream) gas commodity market. The equilibrium outcome of the firms' interaction in the downstream market is explicitly taken into account by the regulator when setting the transport charge. We consider various forms of competition in this market and derive the corresponding optimal transport charge policies. We then run simulations that allow us to perform a comparative welfare analysis of these transport infrastructure investment policies based on different assumptions about the intensity of the competition that prevails in the gas commodity market. (author)

Alternative ways to transport natural gas; Transporte alternativo de gas natural

Energy Technology Data Exchange (ETDEWEB)

Moura, N.R.; Campos, F.B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

The Brazilian energy matrix has been showing a huge increase in the demand of natural gas due mainly to industries and power plants. Today the Brazilian gas market is supplied with gas produced by PETROBRAS and imported from Bolivia. To increase the Brazilian gas supply, on the short and middle term, PETROBRAS will import LNG (liquefied natural gas) and exploit the new offshore fields discovered on the pre-salt area. The only proven technology available today to bring this offshore gas to the market is the pipeline, but its costs for the pre-salt area are high enough to keep the solution economically attractive. So, PETROBRAS are evaluating and developing alternative ways to transport offshore gas, such as LNG, CNG (Compressed Natural Gas), GTS (Gas-to-Solids or Natural Gas Hydrates) and ANG (Adsorbed Natural Gas). Using information available in the literature, this paper analyses the main concepts of CNG and LNG floating unities. This paper also presents the PETROBRAS R and D results on ANG and GTS aiming at offshore application. (author)

Logistic control in automated transportation networks

NARCIS (Netherlands)

Ebben, Mark

2001-01-01

Increasing congestion problems lead to a search for alternative transportation systems. Automated transportation networks, possibly underground, are an option. Logistic control systems are essential for future implementations of such automated transportation networks. This book contributes to the

Thermally rearranged (TR) bismaleimide-based network polymers for gas separation membranes.

Science.gov (United States)

Do, Yu Seong; Lee, Won Hee; Seong, Jong Geun; Kim, Ju Sung; Wang, Ho Hyun; Doherty, Cara M; Hill, Anita J; Lee, Young Moo

2016-11-15

Highly permeable, thermally rearranged polymer membranes based on bismaleimide derivatives that exhibit excellent CO 2 permeability up to 5440 Barrer with a high BET surface area (1130 m 2 g -1 ) are reported for the first time. In addition, the membranes can be easily used to form semi-interpenetrating networks with other polymers endowing them with superior gas transport properties.

Gas mission; Mission gaz

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This preliminary report analyses the desirable evolutions of gas transport tariffing and examines some questions relative to the opening of competition on the French gas market. The report is made of two documents: a synthesis of the previous report with some recommendations about the tariffing of gas transport, about the modalities of network access to third parties, and about the dissociation between transport and trade book-keeping activities. The second document is the progress report about the opening of the French gas market. The first part presents the European problem of competition in the gas supply and its consequences on the opening and operation of the French gas market. The second part presents some partial syntheses about each topic of the mission letter of the Ministry of Economics, Finances and Industry: future evolution of network access tariffs, critical analysis of contractual documents for gas transport and delivery, examination of auxiliary services linked with the access to the network (modulation, balancing, conversion), consideration about the processing of network congestions and denied accesses, analysis of the metering dissociation between the integrated activities of gas operators. Some documents are attached in appendixes: the mission letter from July 9, 2001, the detailed analysis of the new temporary tariffs of GdF and CFM, the offer of methane terminals access to third parties, the compatibility of a nodal tariffing with the presence of three transport operators (GdF, CFM and GSO), the contract-type for GdF supply, and the contract-type for GdF connection. (J.S.)

Synthesis and Gas Transport Properties of Hyperbranched Polyimide–Silica Hybrid/Composite Membranes

Directory of Open Access Journals (Sweden)

Masako Miki

2013-12-01

Full Text Available Hyperbranched polyimide–silica hybrids (HBPI–silica HBDs and hyperbranched polyimide–silica composites (HBPI–silica CPTs were prepared, and their general and gas transport properties were investigated to clarify the effect of silica sources and preparation methods. HBPI–silica HBDs and HBPI–silica CPTs were synthesized by two-step polymerization of A2 + B3 monomer system via polyamic acid as precursor, followed by hybridizing or blending silica sources. Silica components were incorporated by the sol-gel reaction with tetramethoxysilane (TMOS or the addition of colloidal silica. In HBPI-silica HBDs, the aggregation of silica components is controlled because of the high affinity of HBPI and silica caused by the formation of covalent bonds between HBPI and silica. Consequently, HBPI-silica HBDs had good film formability, transparency, and mechanical properties compared with HBPI-silica CPTs. HBPI-silica HBD and CPT membranes prepared via the sol-gel reaction with TMOS showed specific gas permeabilities and permselectivities for CO2/CH4 separation, that is, both CO2 permeability and CO2/CH4 selectivity increased with increasing silica content. This result suggests that gas transport can occur through a molecular sieving effect of the porous silica network derived from the sol-gel reaction and/or through the narrow interfacial region between the silica networks and the organic matrix.

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks

Directory of Open Access Journals (Sweden)

Haiyang Yu

2017-06-01

Full Text Available Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs, for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs and long short-term memory (LSTM neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks.

Science.gov (United States)

Yu, Haiyang; Wu, Zhihai; Wang, Shuqin; Wang, Yunpeng; Ma, Xiaolei

2017-06-26

Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs), for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs) and long short-term memory (LSTM) neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

The southern corridor for natural gas and the last days of Nabucco. Transport of natural gas and Nabucco pipeline; Der suedliche Gaskorridor und die letzten Tage von Nabucco. Gastransport und Nabucco-Pipeline

Energy Technology Data Exchange (ETDEWEB)

Mangott, Gerhard [Innsbruck Univ. (Austria). Fakultaet fuer Politikwissenschaft und Soziologie

2012-11-12

As a strategic project management with a transport capacity of 31 billion m{sup 3} per year of natural gas, Nabucco 1.0 should diversify the natural gas suppliers for the EU market and the import pipeline network. Significant amounts of natural gas should be imported from the Caspian and the Middle East region. Nabucco 1.0 failed as a project management. The Nabucco consortium wants to convey natural gas through a small-scale and cheaper Nabucco west pipeline via Bulgaria, Romania and Hungary to Austria. Also the Trans-Adriatic Pipeline will transport the same natural gas reserves into the European Union (EU).

Natural gas in the transportation sector

Energy Technology Data Exchange (ETDEWEB)

Ask, T Oe; Einang, P M; Stenersen, D [MARINTEK (Norway)

1996-12-01

The transportation sector is responsible for more than 50% of all oil products consumed, and it is the fastest growing oil demand sector and the fastest growing source of emissions. During the last 10 years there have been a considerable and growing effort in developing internal combustion gas engines. This effort has resulted in gas engines with efficiencies comparable to the diesel engines and with emissions considerably lower than engines burning conventional fuels. This development offers us opportunities to use natural gas very efficiently also in the transportation sector, resulting in reduced emissions. However, to utilize all the built in abilities natural gas has as engine fuel, the natural gas composition must be kept within relatively narrow limits. This is the case with both diesel and gasoline today. A further development require therefore specified natural gas compositions, and the direct use of pipeline natural gas as today would only in limited areas be acceptable. An interesting possibility for producing a specified natural gas composition is by LNG (Liquid Natural Gas) production. (EG)

Research on centrality of urban transport network nodes

Science.gov (United States)

Wang, Kui; Fu, Xiufen

2017-05-01

Based on the actual data of urban transport in Guangzhou, 19,150 bus stations in Guangzhou (as of 2014) are selected as nodes. Based on the theory of complex network, the network model of Guangzhou urban transport is constructed. By analyzing the degree centrality index, betweenness centrality index and closeness centrality index of nodes in the network, the level of centrality of each node in the network is studied. From a different point of view to determine the hub node of Guangzhou urban transport network, corresponding to the city's key sites and major transfer sites. The reliability of the network is determined by the stability of some key nodes (transport hub station). The research of network node centralization can provide a theoretical basis for the rational allocation of urban transport network sites and public transport system planning.

Toward Optimal Transport Networks

Science.gov (United States)

Alexandrov, Natalia; Kincaid, Rex K.; Vargo, Erik P.

2008-01-01

Strictly evolutionary approaches to improving the air transport system a highly complex network of interacting systems no longer suffice in the face of demand that is projected to double or triple in the near future. Thus evolutionary approaches should be augmented with active design methods. The ability to actively design, optimize and control a system presupposes the existence of predictive modeling and reasonably well-defined functional dependences between the controllable variables of the system and objective and constraint functions for optimization. Following recent advances in the studies of the effects of network topology structure on dynamics, we investigate the performance of dynamic processes on transport networks as a function of the first nontrivial eigenvalue of the network's Laplacian, which, in turn, is a function of the network s connectivity and modularity. The last two characteristics can be controlled and tuned via optimization. We consider design optimization problem formulations. We have developed a flexible simulation of network topology coupled with flows on the network for use as a platform for computational experiments.

Improving the natural gas transporting based on the steady state simulation results

International Nuclear Information System (INIS)

Szoplik, Jolanta

2016-01-01

The work presents an example of practical application of gas flow modeling results in the network, that was obtained for the existing gas network and for real data about network load depending on the time of day and air temperature. The gas network load in network connections was estimated based on real data concerning gas consumption by customers and weather data in 2010, based on two-parametric model based on the number of degree-days of heating. The aim of this study was to elaborate a relationship between pressure and gas stream introduced into the gas network. It was demonstrated that practical application of elaborated relationship in gas reduction station allows for the automatic adjustment of gas pressure in the network to the volume of network load and maintenance of gas pressure in the whole network at possibly the lowest level. It was concluded based on the results obtained that such an approach allows to reduce the amount of gas supplied to the network by 0.4% of the annual network load. - Highlights: • Determination of the hourly nodal demand for gas by the consumers. • Analysis of the results of gas flow simulation in pipeline network. • Elaboration of the relationship between gas pressure and gas stream feeding the network. • Automatic gas pressure steering in the network depending on the network load. • Comparison of input gas pressure in the system without and with pressure steering.

There Will Be Gas: Gazprom's Transport Strategy in Europe

International Nuclear Information System (INIS)

Bros, Aurelie

2015-10-01

The key role played by Ukraine in the transport of Russian gas and the underground gas storage facilities are a legacy of the Soviet era. The collapse of the USSR forced the Russian Federation to formulate its own national energy strategy after the Soviet Republics and satellite states went independent, to readjust it over time and to define new relationships with these countries regarding the gas sector. The collapse also had the effect of complicating gas transport after 1991 - a reality that had never been a thorny issue before since Ukraine had been formerly integrated into the territory of the Soviet Union. From the mid-1990's onwards, Gazprom has repeatedly tried to control gas transit through Ukraine and other infrastructures from the Soviet era. This effort has been double-pronged: the acquisition of shares in the Ukrainian transit sector (100% owned by the Ukrainian state) and the creation of a joint venture in order to exercise indirect control over the network. Neither of these resulted in success. During the 2000's, especially after the 2004 Orange Revolution, most of the arguments between Ukraine and Russia were based on transit contract, supply agreements, gas debts and management of the transit network. Such a situation led Gazprom-with the support of the Russian government-to adopt a more assertive stance toward Ukraine, i.e. cutting off gas flows intended for Ukraine. The two most serious crises of this nature occurred in 2006 and 2009. Gazprom developed major projects in collaboration with European energy companies to diversify gas supply routes at a time when it anticipated a major increase in European gas demand and the import needs of Russian gas. The Nord Stream pipeline is certainly the best illustration of Gazprom's bypassing policy. From a Russian perspective, transporting gas through the Nord Stream pipeline is much more attractive than Ukraine as Gazprom thereby avoids political tensions, keeps control of the situation and

Study for North-Baranja gas network installation

International Nuclear Information System (INIS)

Anders, S.; Komornoki, L.

1999-01-01

The public administration in Osijecko-Baranjska County in East Slavonia strives for ensuring gas supply for the North Baranja region as part of the regional reconstruction program. MOL Co., Ruhrgas AG., and WGV Co. and Partners have declared their willingness to explore and study the opportunities of gas supply in North Baranja in Croatia. In this context, the three partners have jointly prepared a feasibility study. The study contains four sections: the first briefly outlines the present status in North Baranja and describes the methods of preparing natural gas consumption forecasts. The second section addresses issues related to the dimensioning of the high pressure system transporting gas from Hungary into North Baranja in Croatia, and the required capital expenditures. The third section presents the concept of technical design and engineering, the time planned for implementation as well as capital expenditures for the distribution system. The fourth section introduces the method and results of the profitability analysis. Natural gas consumption in North Baranja is estimated as 20 mcm by 2010. The basic assumption for technical dimensioning the natural gas transmission system, of the region is that the following system components will need to be constructed: 23 km long (PN 25) high pressure system, and 143 km long (PN; 4 bar) medium pressure system, finally 287 km distribution system in cities/ villages. Total capital expenditures for constructing the distribution network are MDEM 32,5 (using 1998 cost levels), according to the study. Of that, the share of the high pressure system will be 20%, the medium pressure system 28,3% and the local distribution network 51,7% (including connections of houses). To prepare the profitability analysis for natural gas supply of North Baranja we used the method of planning a nominal profit statement, balance sheet and cash flow up to 2013. The profitability analysis followed the four options developed for natural gas supply

Forecast on the development of a transport network 2008-2017; Etude prospective sur le developpement du reseau de transport 2008-2017

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

This study on the gas transport network for 2008-2017 is presented in five parts. The first part presents the main characteristics of the GRTgas network and capacity sizing. The second part details the elements presenting a possible impact on the network development. The policy and strategy concerning the infrastructure development are presented in the third part. The part four deals with the development projects needed to the satisfaction of the market capacity supply. The last part is a synthesis of the investments on the period. (A.L.B.)

Inert gas transport in blood and tissues.

Science.gov (United States)

Baker, A Barry; Farmery, Andrew D

2011-04-01

This article establishes the basic mathematical models and the principles and assumptions used for inert gas transfer within body tissues-first, for a single compartment model and then for a multicompartment model. From these, and other more complex mathematical models, the transport of inert gases between lungs, blood, and other tissues is derived and compared to known experimental studies in both animals and humans. Some aspects of airway and lung transfer are particularly important to the uptake and elimination of inert gases, and these aspects of gas transport in tissues are briefly described. The most frequently used inert gases are those that are administered in anesthesia, and the specific issues relating to the uptake, transport, and elimination of these gases and vapors are dealt with in some detail showing how their transfer depends on various physical and chemical attributes, particularly their solubilities in blood and different tissues. Absorption characteristics of inert gases from within gas cavities or tissue bubbles are described, and the effects other inhaled gas mixtures have on the composition of these gas cavities are discussed. Very brief consideration is given to the effects of hyper- and hypobaric conditions on inert gas transport. © 2011 American Physiological Society. Compr Physiol 1:569-592, 2011.

Treating network junctions in finite volume solution of transient gas flow models

Science.gov (United States)

Bermúdez, Alfredo; López, Xián; Vázquez-Cendón, M. Elena

2017-09-01

A finite volume scheme for the numerical solution of a non-isothermal non-adiabatic compressible flow model for gas transportation networks on non-flat topography is introduced. Unlike standard Euler equations, the model takes into account wall friction, variable height and heat transfer between the pipe and the environment which are source terms. The case of one single pipe was considered in a previous reference by the authors, [8], where a finite volume method with upwind discretization of the flux and source terms has been proposed in order to get a well-balanced scheme. The main goal of the present paper is to go a step further by considering a network of pipes. The main issue is the treatment of junctions for which container-like 2D finite volumes are introduced. The couplings between pipes (1D) and containers (2D) are carefully described and the conservation properties are analyzed. Numerical tests including real gas networks are solved showing the performance of the proposed methodology.

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo; Artina, Marco; Foransier, Massimo; Markowich, Peter A.

2015-01-01

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation

Structural Properties of the Brazilian Air Transportation Network.

Science.gov (United States)

Couto, Guilherme S; da Silva, Ana Paula Couto; Ruiz, Linnyer B; Benevenuto, Fabrício

2015-09-01

The air transportation network in a country has a great impact on the local, national and global economy. In this paper, we analyze the air transportation network in Brazil with complex network features to better understand its characteristics. In our analysis, we built networks composed either by national or by international flights. We also consider the network when both types of flights are put together. Interesting conclusions emerge from our analysis. For instance, Viracopos Airport (Campinas City) is the most central and connected airport on the national flights network. Any operational problem in this airport separates the Brazilian national network into six distinct subnetworks. Moreover, the Brazilian air transportation network exhibits small world characteristics and national connections network follows a power law distribution. Therefore, our analysis sheds light on the current Brazilian air transportation infrastructure, bringing a novel understanding that may help face the recent fast growth in the usage of the Brazilian transport network.

Structural Properties of the Brazilian Air Transportation Network

Directory of Open Access Journals (Sweden)

GUILHERME S. COUTO

2015-09-01

Full Text Available The air transportation network in a country has a great impact on the local, national and global economy. In this paper, we analyze the air transportation network in Brazil with complex network features to better understand its characteristics. In our analysis, we built networks composed either by national or by international flights. We also consider the network when both types of flights are put together. Interesting conclusions emerge from our analysis. For instance, Viracopos Airport (Campinas City is the most central and connected airport on the national flights network. Any operational problem in this airport separates the Brazilian national network into six distinct subnetworks. Moreover, the Brazilian air transportation network exhibits small world characteristics and national connections network follows a power law distribution. Therefore, our analysis sheds light on the current Brazilian air transportation infrastructure, bringing a novel understanding that may help face the recent fast growth in the usage of the Brazilian transport network.

Designing optimal greenhouse gas monitoring networks for Australia

Science.gov (United States)

Ziehn, T.; Law, R. M.; Rayner, P. J.; Roff, G.

2016-01-01

Atmospheric transport inversion is commonly used to infer greenhouse gas (GHG) flux estimates from concentration measurements. The optimal location of ground-based observing stations that supply these measurements can be determined by network design. Here, we use a Lagrangian particle dispersion model (LPDM) in reverse mode together with a Bayesian inverse modelling framework to derive optimal GHG observing networks for Australia. This extends the network design for carbon dioxide (CO2) performed by Ziehn et al. (2014) to also minimise the uncertainty on the flux estimates for methane (CH4) and nitrous oxide (N2O), both individually and in a combined network using multiple objectives. Optimal networks are generated by adding up to five new stations to the base network, which is defined as two existing stations, Cape Grim and Gunn Point, in southern and northern Australia respectively. The individual networks for CO2, CH4 and N2O and the combined observing network show large similarities because the flux uncertainties for each GHG are dominated by regions of biologically productive land. There is little penalty, in terms of flux uncertainty reduction, for the combined network compared to individually designed networks. The location of the stations in the combined network is sensitive to variations in the assumed data uncertainty across locations. A simple assessment of economic costs has been included in our network design approach, considering both establishment and maintenance costs. Our results suggest that, while site logistics change the optimal network, there is only a small impact on the flux uncertainty reductions achieved with increasing network size.

Gas transportation tariffs in the european union market

International Nuclear Information System (INIS)

Bianchi, A.

2001-01-01

In a liberalised market, it is an indubitable competitive advantage for a firm to accede at the gas grid with a low cost. The comparison among gas transportation tariffs of 18 European gas transportation companies for a big industrial consumer, shows that Italy is in the medium-high position of the ranking [it

Epidemic Network Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Ruepp, Sarah Renée; Katsikas, Dimitrios; Fagertun, Anna Manolova

2013-01-01

This paper presents a failure propagation model for transport networks which are affected by epidemic failures. The network is controlled using the GMPLS protocol suite. The Susceptible Infected Disabled (SID) epidemic model is investigated and new signaling functionality of GMPLS to support...

Gas transport in graphitic materials

International Nuclear Information System (INIS)

Hoinkis, E.

1995-02-01

The characterization of the gas transport properties of porous solids is of interest in several fields of science and technology. Many catalysts, adsorbents, soils, graphites and carbons are porous. The gas transport through most porous solids can be well described by the dusty gas model invented by Evans, Watson and Mason. This model includes all modes of gas tranport under steady-state conditions, which are Knudsen diffusion, combined Knudsen/continuum diffusion and continuum diffusion, both for gas pairs with equal and different molecular weights. In the absence of a pressure difference gas transport in a pore system can be described by the combined Knudsen/continuum diffusion coefficient D 1 for component 1 in the pores, the Knudsen diffusion coefficient D 1K in the pores, and the continuum diffusion coefficient D 12 for a binary mixture in the pores. The resistance to stationary continuum diffusion of the pores is characterized by a geometrical factor (ε/τ) 12 = (ε/τ)D 12 , were D 12 is the continuum diffusion coefficient for a binary mixture in free space. The Wicke-Kallenbach method was often used to measure D 1 as function of pressure. D 12 and D 1K can be derived from a plot 1/D 1 νs P, and ε/τcan be calculated since D 12 is known. D 1K and the volume of dead end pores can be derived from transient measurements of the diffusional flux at low pressures. From D 1K the expression (ε/τ c ) anti l por may be calculated, which characterizes the pore system for molecular diffusion, where collisions with the pore walls are predominant. (orig.)

Development of natural gas ocean transportation chain by means of natural gas hydrate (NGH)

International Nuclear Information System (INIS)

Nogami, T.; Oya, N.; Ishida, H.; Matsumoto, H.

2008-01-01

Recent studies in Japan have suggested that natural gas hydrate (NGH) transportation of natural gas is more economical than liquefied natural gas (LNG) transportation systems for small, medium and remote gas fields. Researchers in Japan have built a 600 kg per day NGH production and pelletizing plant and regasification facility. This paper discussed feasibility studies conducted in southeast Asia to determine the unit's commercialization potential with large natural gas-related businesses including shipping companies and electric power utilities. The total supply chain was compared with the corresponding liquefied natural gas (LNG) and compressed natural gas (CNG) supply chains. The study also examined natural gas reserves, energy policies, the positioning of natural gas supplies, and future forecasts of natural gas demand. A conceptual design for an NGH supply chain in Indonesia was presented. Results of the study have demonstrated that the NGH chain is an appropriate and economically feasible transportation method for many areas in southeast Asia. 8 refs., 10 figs

Ecoefficiency indicators for natural gas transportation companies; Proposta de indicadores de desempenho ambiental para empresas do segmento de transporte de gas natural

Energy Technology Data Exchange (ETDEWEB)

La Rovere, Emilio Lebre; Mariano, Jacqueline Barboza; Garcia, Katia Cristina; Salgado, Vivian Gullo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Planejamento Energetico; Faertes, Denise [TRANSPETRO - PETROBRAS Transporte, Rio de Janeiro, RJ (Brazil); Barata, Martha Macedo de Lima [Fundacao Inst. Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil)

2005-07-01

This paper aims to present a cast of environmental indicators, more specifically ecoefficiency indicators, to natural gas pipeline transportation companies. So as to do that, are defined the concepts of ecoefficiency and sustainability with its principal related environmental indicators. The environmental impacts and aspects of the natural gas pipeline transportation are discussed, and the concept of cleaner service and production is considered in the context of this activity. Are also presented and analyzed the most important indicators of environmental performance used by oil and gas companies and by natural gas transportation companies, so as to support the choice of the proposed indicators. Finally, the cast of the indicators, which was based on the assessment of the Brazilian Northeast System of gas pipelines, operated by PETROBRAS Transporte S.A., TRANSPETRO, is presented. (author)

Global Optimization for Transport Network Expansion and Signal Setting

OpenAIRE

Liu, Haoxiang; Wang, David Z. W.; Yue, Hao

2015-01-01

This paper proposes a model to address an urban transport planning problem involving combined network design and signal setting in a saturated network. Conventional transport planning models usually deal with the network design problem and signal setting problem separately. However, the fact that network capacity design and capacity allocation determined by network signal setting combine to govern the transport network performance requires the optimal transport planning to consider the two pr...

Price cap regulation: the case of natural gas transport in the UK; La reglementation par price cap: le cas du transport de gaz naturel au Royaume Uni

Energy Technology Data Exchange (ETDEWEB)

David, L. [ATER, Paris-1 Univ., 75 (France)

1999-09-01

The transport and storage activities of British Gas company are controlled by a distinct organization named Transco. The access charges paid by the suppliers for the use of Transco's network are regulated by a price cap since October 1, 1994. However, Ofgas, the office of gas supply which is the regulation authority in charge of the control of competition and of British Gas activities, considers this control system as inefficient and has chosen a RPI (retail price index)-X (expected productivity factor)-type price cap for the control of gas transport tariffs. This has led to a disagreement between Transco and Ofgas which has delayed the implementation of the new system up to February 1998. This article compares the choices made by Ofgas for the control of gas transport tariffs with the economical theory. It recalls first, the reasons why the price cap appears as more efficient than the service cost regulation, the alternate method used by regulation authorities to control the tariffs of natural monopolies. Then, the difficulties linked with the implementation of the price cap for the transport of natural gas in the UK are analyzed in order to explain the reasons that led Ofgas to change its formula. Finally, the bases of an optimum hybrid formula are proposed. (J.S.)

Determination of oxygen effective diffusivity in porous gas diffusion layer using a three-dimensional pore network model

International Nuclear Information System (INIS)

Wu Rui; Zhu Xun; Liao Qiang; Wang Hong; Ding Yudong; Li Jun; Ye Dingding

2010-01-01

In proton exchange membrane fuel cell (PEMFC) models, oxygen effective diffusivity is the most important parameter to characterize the oxygen transport in the gas diffusion layer (GDL). However, its determination is a challenge due to its complex dependency on GDL structure. In the present study, a three-dimensional network consisting of spherical pores and cylindrical throats is developed and used to investigate the effects of GDL structural parameters on oxygen effective diffusivity under the condition with/without water invasion process. Oxygen transport in the throat is described by Fick's law and water invasion process in the network is simulated using the invasion percolation with trapping algorithm. The simulation results reveal that oxygen effective diffusivity is slightly affected by network size but increases with decreasing the network heterogeneity and with increasing the pore connectivity. Impacts of network anisotropy on oxygen transport are also investigated in this paper. The anisotropic network is constructed by constricting the throats in the through-plane direction with a constriction factor. It is found that water invasion has a more severe negative influence on oxygen transport in an anisotropic network. Finally, two new correlations are introduced to determine the oxygen effective diffusivity for the Toray carbon paper GDLs.

Natural gas transport, regulation in UK

International Nuclear Information System (INIS)

Goldoni, Giovanni

2005-01-01

The detailed analysis contained in this case history demonstrates the great efforts made in the field of incentive regulation in order to promote competition in the gas market and to improve the efficiency of the gas transport system. The next challenge will be to preserve competition and efficiency in a quite different gas-supply condition [it

Transport of liquefied natural gas by tankers

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, Y N; Mkrtychan, Y S; Tregubov, I A; Belyaev, I G

1979-03-01

A survey conducted by the USSR's VNIIgaz indicates that the number of LNG tankers in use and under construction presently exceeds 100, ranging in capacity from 600 to 130,000 m/sup 3/. The annual volume of LNG transported by tanker is expected to reach 50 to 60 billion m/sup 3/ by 1980. VNIIgaz examines (1) the design of present tankers, (2) the differences in gas-transport temperature, insulation, and engines, (3) transport recommendations of various LNG-tanker companies around the world, (4) parameters of some types of commercial diesel engines used for tanker propulsion (fueled by gas and/or heavy fuel oil), (5) relative advantages and disadvantages of diesel engines, and (6) the control system for the main gas diesel of an LNG tanker.

Compressed natural gas transportation by utilizing FRP composite pressure vessels

Energy Technology Data Exchange (ETDEWEB)

Campbell, S.C. [Trans Ocean Gas Inc., St. John' s, NF (Canada)

2004-07-01

This paper discussed the Trans Ocean Gas (TOG) method for transporting compressed natural gas (CNG). As demand for natural gas increases and with half of the world's reserves considered stranded, a method to transport natural gas by ship is needed. CNG transportation is widely viewed as a viable method. Transported as CNG, stranded gas reserves can be delivered to existing markets or can create new natural gas markets not applicable to liquefied natural gas (LNG). In contrast to LNG, compressed gas requires no processing to offload. TOG proposes that CNG be transported using fiber reinforced plastic (FRP) pressure vessels which overcome all the deficiencies of proposed steel-based systems. FRP pressure vessels have been proven safe and reliable through critical applications in the national defense, aerospace, and natural gas vehicle industries. They are light-weight, highly reliable, have very safe failure modes, are corrosion resistant, and have excellent low temperature characteristics. Under TOG's scheme, natural gas can be stored at two thirds the density of LNG without costly processing. TOG's proposed design and testing of a CNG system was reviewed in detail. 1 fig.

Multi-Objective Design Of Optimal Greenhouse Gas Observation Networks

Science.gov (United States)

Lucas, D. D.; Bergmann, D. J.; Cameron-Smith, P. J.; Gard, E.; Guilderson, T. P.; Rotman, D.; Stolaroff, J. K.

2010-12-01

One of the primary scientific functions of a Greenhouse Gas Information System (GHGIS) is to infer GHG source emission rates and their uncertainties by combining measurements from an observational network with atmospheric transport modeling. Certain features of the observational networks that serve as inputs to a GHGIS --for example, sampling location and frequency-- can greatly impact the accuracy of the retrieved GHG emissions. Observation System Simulation Experiments (OSSEs) provide a framework to characterize emission uncertainties associated with a given network configuration. By minimizing these uncertainties, OSSEs can be used to determine optimal sampling strategies. Designing a real-world GHGIS observing network, however, will involve multiple, conflicting objectives; there will be trade-offs between sampling density, coverage and measurement costs. To address these issues, we have added multi-objective optimization capabilities to OSSEs. We demonstrate these capabilities by quantifying the trade-offs between retrieval error and measurement costs for a prototype GHGIS, and deriving GHG observing networks that are Pareto optimal. [LLNL-ABS-452333: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Transport on river networks: A dynamical approach

OpenAIRE

Zaliapin, I; Foufoula-Georgiou, E; Ghil, M

2017-01-01

This study is motivated by problems related to environmental transport on river networks. We establish statistical properties of a flow along a directed branching network and suggest its compact parameterization. The downstream network transport is treated as a particular case of nearest-neighbor hierarchical aggregation with respect to the metric induced by the branching structure of the river network. We describe the static geometric structure of a drainage network by a tree, referred to as...

Strategies for optical transport network recovery under epidemic network failures

DEFF Research Database (Denmark)

Ruepp, Sarah Renée; Fagertun, Anna Manolova; Kosteas, Vasileios

2015-01-01

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under different failure scenarios. This work evaluates two rerouting strategies and proposes four policies for failure handling in a connection-oriented optical transport network, under generalized multiprotocol label switching control plane. The performance of the strategies and the policies......, and that there exist a clear trade-off between policy performance and network resource consumption, which must be addressed by network operators for improved robustness of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections...

Optimal transportation networks models and theory

CERN Document Server

Bernot, Marc; Morel, Jean-Michel

2009-01-01

The transportation problem can be formalized as the problem of finding the optimal way to transport a given measure into another with the same mass. In contrast to the Monge-Kantorovitch problem, recent approaches model the branched structure of such supply networks as minima of an energy functional whose essential feature is to favour wide roads. Such a branched structure is observable in ground transportation networks, in draining and irrigation systems, in electrical power supply systems and in natural counterparts such as blood vessels or the branches of trees. These lectures provide mathematical proof of several existence, structure and regularity properties empirically observed in transportation networks. The link with previous discrete physical models of irrigation and erosion models in geomorphology and with discrete telecommunication and transportation models is discussed. It will be mathematically proven that the majority fit in the simple model sketched in this volume.

[Natural gas rate design and transportation issues

International Nuclear Information System (INIS)

Howard, G.S.

1992-01-01

This paper is presented from an industrial user viewpoint with regards to natural gas distribution and pricing. The author reviews the problems with rate structures at local distributing companies and gas utility companies which resort to charging high prices to industrial users while subsidizing residential users. He goes on then to discuss the lack of innovation amount LDCs to meet the needs of the industrial sector. Secondly it analyses the regulation and price structure of the pipeline industry which drastically affects all gas prices. The paper specifically discusses 'equivalent margin rates' which are being used by many states to control transportation rates. The author feels that these margin rates are inappropriate in that it transfers much of the LDC's exploration and development costs to the pipeline company which transfers it on to the consumer. He feels that the transportation rates should exclude all costs that are clearly not incurred by an LDC to provide transportation service. The paper concludes with recommendations to regulators regarding the need for regulatory reform of deregulation of the gas industry with regards to profit-taking and the transportation industry with regards to developing capacity assignment programs

Gas Transport and Exchange through Wetland Plant Aerenchyma

DEFF Research Database (Denmark)

Sorrell, Brian Keith; Brix, Hans

2013-01-01

Aerenchyma, the large airspaces in aquatic plants, is a rapid gas transport pathway between atmosphere and soil in wetlands. Oxygen transport aerates belowground tissue and oxidizes rhizosphere soil, an important process in wetland biogeochemistry. Most plant O2 transport occurs by diffusion......, and the major challenge for its accurate measurement is avoiding disturbing small-scale gradients in O2 concentration and demand in the pathway. Small O2 sensors with rapid response times and high spatial resolution are the most popular methods for quantifying O2 transport and rhizosphere oxidation...... such as stirring of solutions. In some species, pressurized gas flows develop in shoots and rhizomes, and their contribution to gas fluxes can be assessed with pressure transducers and flow meters. Other gases produced in wetlands (e.g., CO2, CH4, and N2O) are also transported in aerenchyma. Their fluxes...

Radon as a natural tracer for gas transport within uranium waste rock piles

International Nuclear Information System (INIS)

Silva, N.C.; Chagas, E.G.L.; Dias, D.C.S.; Guerreiro, E.T.Z.; Alberti, H.L.C.; Braz, M.L.; Abreu, C.B.; Lopez, D.; Branco, O.; Fleming, P.

2014-01-01

Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Industrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222 Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222 Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m -3 with mean concentration of 320.7±263.3 kBq m -3 . (authors)

Physics of gas breakdown for ion beam transport in gas

International Nuclear Information System (INIS)

Olson, C.L.; Poukey, J.W.; Hinshelwood, D.D.; Rose, D.V.; Hubbard, R.F.; Lampe, M.; Neri, J.M.; Ottinger, P.F.; Slinker, S.P.; Stephanakis, S.J.; Young, F.C.; Welch, D.R.

1993-01-01

Detailed analysis, experiments, and computer simulations are producing a new understanding of gas breakdown during intense ion beam transport in neutral gas. Charge neutralization of beam micro clumps is shown to limit the net clump potentials to a non-zero value π min , which can lead to divergence growth and axial energy spreading. At pressures approx-gt 1 Torr, plasma shielding should substantially reduce this effect Current neutralization has been studied in experiments on the GAMBLE II accelerator. The importance of fast electrons (knockons and runaways) has been established in IPROP simulations, which are in agreement with the experiments. For light ion fusion parameters with pressures approx-gt 1 Torr, very small net current fractions (much-lt 1%) appear feasible, permitting ballistic transport in gas. Self-pinched requires higher net current fractions (≥ 2%) and preliminary IPROP code results indicate that this appears achievable for small-radius intense beams in lower pressure gases (approx-gt Torr). Several self-pinched transport concepts look promising. The importance of these results for both light ion fusion and heavy ion fusion is discussed

Natural gas transport with the aid of pipelines

Energy Technology Data Exchange (ETDEWEB)

Volk, A

1978-01-01

After giving a brief explanation on the term natural gas and the chemical composition of natural gases of different origin, the natural gas supply in the FRG and in Western Europe is discussed. Other discussions are included on: (1) planning, construction, and operation of the pipelines; (2) the equipment for pressure increase and the telecommunication equipment which are urgently necessary for gas transport through pipelines; (3) the problem of safety both in connection with the supply and protection of man and material; and (4) problems of profitability of natural gas transport through pipelines.

Risk Analysis on Leakage Failure of Natural Gas Pipelines by Fuzzy Bayesian Network with a Bow-Tie Model

OpenAIRE

Shan, Xian; Liu, Kang; Sun, Pei-Liang

2017-01-01

Pipeline is the major mode of natural gas transportation. Leakage of natural gas pipelines may cause explosions and fires, resulting in casualties, environmental damage, and material loss. Efficient risk analysis is of great significance for preventing and mitigating such potential accidents. The objective of this study is to present a practical risk assessment method based on Bow-tie model and Bayesian network for risk analysis of natural gas pipeline leakage. Firstly, identify the potential...

The development of a natural gas transportation logistics management system

International Nuclear Information System (INIS)

Pereira dos Santos, Sidney; Eugenio Leal, Jose; Oliveira, Fabricio

2011-01-01

Efficient management of the natural gas business chain - based on pipeline transmission networks and taking into consideration the interaction among the main players (e.g., shippers, suppliers, transmission companies and local distribution companies) - requires the use of decision-making support systems. These support systems maximise resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages and market demand shortfalls. This study presents a practical use for technologies, such as a thermohydraulic simulation of gas flow through pipelines, a Monte Carlo simulation for compressor station availability studies, an economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for the maximisation of income and the minimisation of contractual penalties. The proposed system allows the optimum availability level to be defined and maintained by the Transporter (by installing reserve capacity) to mitigate losses related to revenue and contractual penalties. It also economically identifies, quantifies and justifies the installation of stand-by compressor units that can mitigate the Transporter's exposure to losses caused by capacity shortfalls as a consequence of scheduled and non-scheduled outages. - Highlights: → We present a DSS to help the decision on investments on spare compressor units of pipelines systems. → The system may be applied to new or existing projects. → The system is able to estimate the revenue losses and the contractual penalties. → An economical evaluation shows the NPV for each configuration of spare units. → The method was applied to the case study of the Bolivia-Brazil gas pipeline.

The development of a natural gas transportation logistics management system

Energy Technology Data Exchange (ETDEWEB)

Pereira dos Santos, Sidney [Petroleo Brasileiro S.A.-PETROBRAS, Av. Almirante Barroso, 81, 12 andar, Centro, Rio de Janeiro RJ 20031-004 (Brazil); Eugenio Leal, Jose, E-mail: jel@puc-rio.br [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Department of Industrial Engineering, R. Marques de S. Vicente 225, Gavea. Rio de Janeiro RJ 22451-900 (Brazil); Oliveira, Fabricio [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Department of Industrial Engineering, R. Marques de S. Vicente 225, Gavea. Rio de Janeiro RJ 22451-900 (Brazil)

2011-09-15

Efficient management of the natural gas business chain - based on pipeline transmission networks and taking into consideration the interaction among the main players (e.g., shippers, suppliers, transmission companies and local distribution companies) - requires the use of decision-making support systems. These support systems maximise resources and mitigate contingencies due to gas supply shortfalls, operational contingencies from scheduled and non-scheduled equipment outages and market demand shortfalls. This study presents a practical use for technologies, such as a thermohydraulic simulation of gas flow through pipelines, a Monte Carlo simulation for compressor station availability studies, an economic risk evaluation related to potential revenue losses and contractual penalties and linear programming for the maximisation of income and the minimisation of contractual penalties. The proposed system allows the optimum availability level to be defined and maintained by the Transporter (by installing reserve capacity) to mitigate losses related to revenue and contractual penalties. It also economically identifies, quantifies and justifies the installation of stand-by compressor units that can mitigate the Transporter's exposure to losses caused by capacity shortfalls as a consequence of scheduled and non-scheduled outages. - Highlights: > We present a DSS to help the decision on investments on spare compressor units of pipelines systems. > The system may be applied to new or existing projects. > The system is able to estimate the revenue losses and the contractual penalties. > An economical evaluation shows the NPV for each configuration of spare units. > The method was applied to the case study of the Bolivia-Brazil gas pipeline.

System analysis and planning of a gas distribution network

Energy Technology Data Exchange (ETDEWEB)

Salas, Edwin F.M.; Farias, Helio Monteiro [AUTOMIND, Rio de Janeiro, RJ (Brazil); Costa, Carla V.R. [Universidade Salvador (UNIFACS), BA (Brazil)

2009-07-01

The increase in demand by gas consumers require that projects or improvements in gas distribution networks be made carefully and safely to ensure a continuous, efficient and economical supply. Gas distribution companies must ensure that the networks and equipment involved are defined and designed at the appropriate time to attend to the demands of the market. To do that a gas distribution network analysis and planning tool should use distribution networks and transmission models for the current situation and the future changes to be implemented. These models are used to evaluate project options and help in making appropriate decisions in order to minimize the capital investment in new components or simple changes in operational procedures. Gas demands are increasing and it is important that gas distribute design new distribution systems to ensure this growth, considering financial constraints of the company, as well as local legislation and regulation. In this study some steps of developing a flexible system that attends to those needs will be described. The analysis of distribution requires geographically referenced data for the models as well as an accurate connectivity and the attributes of the equipment. GIS systems are often used as a deposit center that holds the majority of this information. GIS systems are constantly updated as distribution network equipment is modified. The distribution network modeling gathered from this system ensures that the model represents the current network condition. The benefits of this architecture drastically reduce the creation and maintenance cost of the network models, because network components data are conveniently made available to populate the distribution network. This architecture ensures that the models are continually reflecting the reality of the distribution network. (author)

Transport of gas from disk to halo in starforming galaxies

Directory of Open Access Journals (Sweden)

Shevchenko Mikhail G.

2017-12-01

Full Text Available Using 3-D gas dynamic simulations, we study the supernova (SNe driven transport of gas from the galactic disk. We assume that SNe are distributed randomly and uniformly in the galactic plane and we consider sufficiently high volume SNe rates that are typical for starforming galaxies: νSN = (0.3 − 3 × 10−11 pc−3 yr−1. We found that under such conditions, a major part of gas locked initially in the galactic disk is transported up to ∼ 1 − 5 stellar scale heights within several millions years. As expected gas transport is more efficient in the case of a thinner stellar disk. An decrease/increase of SN rate in the galactic disk with the same stellar scale height leads to an enlarging/shortening of time scale for gas transport. Independent of SN rate, the major fraction of the swept up gas is in the cold phase (T 106 K is elevated to larger heights than cold gas.

Density-based and transport-based core-periphery structures in networks.

Science.gov (United States)

Lee, Sang Hoon; Cucuringu, Mihai; Porter, Mason A

2014-03-01

Networks often possess mesoscale structures, and studying them can yield insights into both structure and function. It is most common to study community structure, but numerous other types of mesoscale structures also exist. In this paper, we examine core-periphery structures based on both density and transport. In such structures, core network components are well-connected both among themselves and to peripheral components, which are not well-connected to anything. We examine core-periphery structures in a wide range of examples of transportation, social, and financial networks-including road networks in large urban areas, a rabbit warren, a dolphin social network, a European interbank network, and a migration network between counties in the United States. We illustrate that a recently developed transport-based notion of node coreness is very useful for characterizing transportation networks. We also generalize this notion to examine core versus peripheral edges, and we show that the resulting diagnostic is also useful for transportation networks. To examine the properties of transportation networks further, we develop a family of generative models of roadlike networks. We illustrate the effect of the dimensionality of the embedding space on transportation networks, and we demonstrate that the correlations between different measures of coreness can be very different for different types of networks.

Transport of natural gas; criterions for the infrastructure planning

International Nuclear Information System (INIS)

Unidad de Planeacion Minero Energetica, UPME

1999-01-01

The planning of the expansion of transport of natural gas system; should keep in mind the changes that are happening in the structure of this industry in the country. In this respect, it is growing the number of actors private present in her, what determines a indicative type planning, whose main objective is to serve as information or guide in decisions of investment involved agents in the maintenance and the amplification of the net of transport for the national supply of natural gas. An indicative plan has objectives different to those of an operative plan of short term. While this last search to establish a program of adjustments to manage commitments of transport and to maintain, this way, the validity of the gas pipeline, The indicative plan of transport is guided to quantify the intensity of the financial effort that is required so that the capacity of the gas pipeline net, responds to the prospective growth of the gas industry. In other words, the indicative plan should contribute to identify the type of works and the one mounts of the investments that the transport of gas system needs in the long term. In this sense, it is important to specify the function objective that will optimize, this precision it should take into account, in our case, the foreseen expansion of the electric sector, because this it depends in good measure of the costs and of the geographical readiness of fuels as the natural gas and the coal. Said otherwise, the function objective that should be optimized involves the expansion of the net of transport of natural gas and the expansion of the generation capacity simultaneously and of the infrastructure of electricity transmission

Gas transport in solid oxide fuel cells

CERN Document Server

He, Weidong; Dickerson, James

2014-01-01

This book provides a comprehensive overview of contemporary research and emerging measurement technologies associated with gas transport in solid oxide fuel cells. Within these pages, an introduction to the concept of gas diffusion in solid oxide fuel cells is presented. This book also discusses the history and underlying fundamental mechanisms of gas diffusion in solid oxide fuel cells, general theoretical mathematical models for gas diffusion, and traditional and advanced techniques for gas diffusivity measurement.

Gas transport during in vitro and in vivo preclinical testing of inert gas therapies

Directory of Open Access Journals (Sweden)

Ira Katz

2016-01-01

Full Text Available New gas therapies using inert gases such as xenon and argon are being studied, which require in vitro and in vivo preclinical experiments. Examples of the kinetics of gas transport during such experiments are analyzed in this paper. Using analytical and numerical models, we analyze an in vitro experiment for gas transport to a 96 cell well plate and an in vivo delivery to a small animal chamber, where the key processes considered are the wash-in of test gas into an apparatus dead volume, the diffusion of test gas through the liquid media in a well of a cell test plate, and the pharmacokinetics in a rat. In the case of small animals in a chamber, the key variable controlling the kinetics is the chamber wash-in time constant that is a function of the chamber volume and the gas flow rate. For cells covered by a liquid media the diffusion of gas through the liquid media is the dominant mechanism, such that liquid depth and the gas diffusion constant are the key parameters. The key message from these analyses is that the transport of gas during preclinical experiments can be important in determining the true dose as experienced at the site of action in an animal or to a cell.

Direct monitoring of wind-induced pressure-pumping on gas transport in soil

Science.gov (United States)

Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

2017-04-01

Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non

4. report of study group 6.3. Gas for transportation - gas vehicles

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The report at hand has been compiled by the International Gas Union Study Group 6.3, which included representatives of 12 different countries. Currently there are about 5.5 million gas vehicles in the world. Of the world vehicle population, that equals less than 1 %. However, just recently in many countries there seem to be new, very rapid developments regarding gas vehicles, as both local and national governments are becoming increasingly aware of exhaust emissions, energy efficiency and security, and the possibilities offered by alternative fuels. This report is intended to give examples and ideas for the gas industry regarding business opportunities in the transportation sector. The principal goal of the report is to provide the reader a thorough picture of the current state-of-the art technology and development trends regarding use of gaseous fuels in the road transportation sector. Thus, the report includes information on technical topics such as different gases, engines, fuel systems, vehicles, and refueling infrastructure. It also addresses the market situation, including legislative and fiscal issues as well as customer awareness issues. The ideas and future prospects, which are compiled in the outlook and conclusion sections, present business opportunities for the participation of the gas industry as an energy provider in the transportation sector. (author)

Graphs, Ideal Flow, and the Transportation Network

OpenAIRE

Teknomo, Kardi

2016-01-01

This lecture discusses the mathematical relationship between network structure and network utilization of transportation network. Network structure means the graph itself. Network utilization represent the aggregation of trajectories of agents in using the network graph. I show the similarity and relationship between the structural pattern of the network and network utilization.

Calculation models for prediction of Liquefied Natural Gas (LNG) ageing during ship transportation

Energy Technology Data Exchange (ETDEWEB)

Miana, Mario; Hoyo, Rafael del; Rodrigalvarez, Vega; Valdes, Jose Ramon [Instituto Tecnologico de Aragon, Area de Investigacion, Desarrollo y Servicios Tecnologicos, Maria de Luna 7, 50018 Zaragoza (Spain); Llorens, Raul [ENAGAS SA, Direccion de Ingenieria y Tecnologia del Gas, Autovia A - 2, km. 306.4, 50012 Zaragoza (Spain)

2010-05-15

A group of European gas transportation companies within the European Gas Research Group launched in 2007 the 'MOLAS' Project to provide a software program for the analysis of the Liquefied Natural Gas (LNG) ageing process during ship transportation. This program contains two different modeling approaches: a physical algorithm and an 'intelligent' model. Both models are fed with the same input data, which is composed of the ship characteristics (BOR and capacity), voyage duration, LNG composition, temperature, pressure, and volume occupied by liquid phase at the port of origin, together with pressure at the port of destination. The results obtained are the LNG composition, temperature and liquid volume at the port of destination. Furthermore, the physical model obtains the evolution over time of such variables en route as it is based on unsteady mass balances over the system, while the i-model applies neural networks to obtain regression coefficients from historical data composed only of origin and destination measurements. This paper describes both models and validates them from previous published models and experimental data measured in ENAGAS LNG regasification plants. (author)

The transport system for natural gas

International Nuclear Information System (INIS)

Bjoerndalen, Joergen; Nese, Gjermund

2003-01-01

In 2002, the actors on the Norwegian shelf in cooperation with the authorities established a new regime for sale and transport of gas. This article deals with some issues of interest relating to this new regime. The transport system for natural gas shows clear signs of being a natural monopoly, which makes it difficult to use the system efficiently. Two main problems of the current way of organizing are pointed out: (1) lack of price and market signals in capacity allocation and (2) unclear incentive effects. The article indicates a possible solution based on the form of organization that is used in the power market

Application of neural networks to prediction of phase transport characteristics in high-pressure two-phase turbulent bubbly flows

International Nuclear Information System (INIS)

Yang, A.-S.; Kuo, T.-C.; Ling, P.-H.

2003-01-01

The phase transport phenomenon of the high-pressure two-phase turbulent bubbly flow involves complicated interfacial interactions of the mass, momentum, and energy transfer processes between phases, revealing that an enormous effort is required in characterizing the liquid-gas flow behavior. Nonetheless, the instantaneous information of bubbly flow properties is often desired for many industrial applications. This investigation aims to demonstrate the successful use of neural networks in the real-time determination of two-phase flow properties at elevated pressures. Three back-propagation neural networks, trained with the simulation results of a comprehensive theoretical model, are established to predict the transport characteristics (specifically the distributions of void-fraction and axial liquid-gas velocities) of upward turbulent bubbly pipe flows at pressures covering 3.5-7.0 MPa. Comparisons of the predictions with the test target vectors indicate that the averaged root-mean-squared (RMS) error for each one of three back-propagation neural networks is within 4.59%. In addition, this study appraises the effects of different network parameters, including the number of hidden nodes, the type of transfer function, the number of training pairs, the learning rate-increasing ratio, the learning rate-decreasing ratio, and the momentum value, on the training quality of neural networks.

Optimization of investments in gas networks

International Nuclear Information System (INIS)

Andre, J.

2010-09-01

The natural gas networks require very important investments to cope with a still growing demand and to satisfy the new regulatory constraints. The gas market deregulation imposed to the gas network operators, first, transparency rules of a natural monopoly to justify their costs and ultimately their tariffs, and, second, market fluidity objectives in order to facilitate access for competition to the end-users. These major investments are the main reasons for the use of optimization techniques aiming at reducing the costs. Due to the discrete choices (investment location, limited choice of additional capacities, timing) crossed with physical non linear constraints (flow/pressures relations in the pipe or operating ranges of compressors), the programs to solve are Large Mixed Non Linear Programs (MINLP). As these types of programs are known to be hard to solve exactly in polynomial times (NP-hard), advanced optimization methods have to be implemented to obtain realistic results. The objectives of this thesis are threefold. First, one states several investment problems modeling of natural gas networks from industrial world motivations. Second, one identifies the most suitable methods and algorithms to the formulated problems. Third, one exposes the main advantages and drawbacks of these methods with the help of numerical applications on real cases. (author)

Gas Classification Using Deep Convolutional Neural Networks

Science.gov (United States)

Peng, Pai; Zhao, Xiaojin; Pan, Xiaofang; Ye, Wenbin

2018-01-01

In this work, we propose a novel Deep Convolutional Neural Network (DCNN) tailored for gas classification. Inspired by the great success of DCNN in the field of computer vision, we designed a DCNN with up to 38 layers. In general, the proposed gas neural network, named GasNet, consists of: six convolutional blocks, each block consist of six layers; a pooling layer; and a fully-connected layer. Together, these various layers make up a powerful deep model for gas classification. Experimental results show that the proposed DCNN method is an effective technique for classifying electronic nose data. We also demonstrate that the DCNN method can provide higher classification accuracy than comparable Support Vector Machine (SVM) methods and Multiple Layer Perceptron (MLP). PMID:29316723

Gas Classification Using Deep Convolutional Neural Networks.

Science.gov (United States)

Peng, Pai; Zhao, Xiaojin; Pan, Xiaofang; Ye, Wenbin

2018-01-08

In this work, we propose a novel Deep Convolutional Neural Network (DCNN) tailored for gas classification. Inspired by the great success of DCNN in the field of computer vision, we designed a DCNN with up to 38 layers. In general, the proposed gas neural network, named GasNet, consists of: six convolutional blocks, each block consist of six layers; a pooling layer; and a fully-connected layer. Together, these various layers make up a powerful deep model for gas classification. Experimental results show that the proposed DCNN method is an effective technique for classifying electronic nose data. We also demonstrate that the DCNN method can provide higher classification accuracy than comparable Support Vector Machine (SVM) methods and Multiple Layer Perceptron (MLP).

Transport Properties of operational gas mixtures used at LHC

CERN Document Server

Assran, Yasser

2011-01-01

This report summarizes some useful data on the transport characteristics of gas mixtures which are required for detection of charged particles in gas detectors. We try to replace Freon used for RPC detector in the CMS experiment with another gas while maintaining the good properties of the Freon gas mixture unchanged. We try to switch to freonless gas mixture because Freon is not a green gas, it is very expensive and its availability is decreasing. Noble gases like Ar, He, Ne and Xe (with some quenchers like carbon dioxide, methane, ethane and isobutene) are investigated. Transport parameters like drift velocity, diffusion, Townsend coefficient, attachment coefficient and Lorentz angle are computed using Garfield software for different gas mixtures and compared with experimental data.

Photo-induced Mass Transport through Polymer Networks

Science.gov (United States)

Meng, Yuan; Anthamatten, Mitchell

2014-03-01

Among adaptable materials, photo-responsive polymers are especially attractive as they allow for spatiotemporal stimuli and response. We have recently developed a macromolecular network capable of photo-induced mass transport of covalently bound species. The system comprises of crosslinked chains that form an elastic network and photosensitive fluorescent arms that become mobile upon irradiation. We form loosely crosslinked polymer networks by Michael-Addition between multifunctional thiols and small molecule containing acrylate end-groups. The arms are connected to the network by allyl sulfide, that undergoes addition-fragmentation chain transfer (AFCT) in the presence of free radicals, releasing diffusible fluorophore. The networks are loaded with photoinitiator to allow for spatial modulation of the AFCT reactions. FRAP experiments within bulk elastomers are conducted to establish correlations between the fluorophore's diffusion coefficient and experimental variables such as network architecture, temperature and UV intensity. Photo-induced mass transport between two contacted films is demonstrated, and release of fluorophore into a solvent is investigated. Spatial and temporal control of mass transport could benefit drug release, printing, and sensing applications.

Solutions to operate transmission and distribution gas networks

Directory of Open Access Journals (Sweden)

Neacsu Sorin

2017-01-01

Full Text Available In order to respect the actual and future regulations, besides SCADA, there is a need for further modern operating solutions for the transmission and distribution gas network. The paper presents the newest operating principles and modern software solutions that represent a considerable help to operate the transmission and distribution gas networks.

Separation of British Gas' transportation and storage business

International Nuclear Information System (INIS)

McGregor, G.

1992-12-01

In making his substantive reference of the transportation and storage business of British Gas to the Monopolies and Mergers Commission, the Director General of Gas Supply identified the following principal effects adverse to the public interest: ''The absence of provision for the establishment of an independent undertaking to operate the pipe-line system and other facilities used by British Gas for the conveyance and storage of gas which would not be subject to conflicting interests in securing (a) transparency of the prices charged, the costs incurred and the operating methods in respect of the conveyance and storage of gas; (b) proper allocation to various parts of the Gas Supply Business of costs incurred and returns by that business; and (c) protection of information relating to the conveyance and storage of gas from which British Gas might obtain unfair commercial advantage, and thereby avoid the restriction or distortion of competition between British Gas and other persons whose business consists of or includes the supply of gas''. This paper considers the structural issues associated with achieving effective competition and looks at how the relationship between the businesses of supply and transportation might be organised in the short and longer term. (Author)

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Directory of Open Access Journals (Sweden)

Dietmar Gerteisen

2013-09-01

Full Text Available In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

Transportation Network Topologies

Science.gov (United States)

Alexandrov, Natalia (Editor)

2004-01-01

The existing U.S. hub-and-spoke air transportation system is reaching saturation. Major aspects of the current system, such as capacity, safety, mobility, customer satisfaction, security, communications, and ecological effects, require improvements. The changing dynamics - increased presence of general aviation, unmanned autonomous vehicles, military aircraft in civil airspace as part of homeland defense - contributes to growing complexity of airspace. The system has proven remarkably resistant to change. NASA Langley Research Center and the National Institute of Aerospace conducted a workshop on Transportation Network Topologies on 9-10 December 2003 in Williamsburg, Virginia. The workshop aimed to examine the feasibility of traditional methods for complex system analysis and design as well as potential novel alternatives in application to transportation systems, identify state-of-the-art models and methods, conduct gap analysis, and thus to lay a foundation for establishing a focused research program in complex systems applied to air transportation.

Computer-Supported Modelling of Multi modal Transportation Networks Rationalization

Directory of Open Access Journals (Sweden)

Ratko Zelenika

2007-09-01

Full Text Available This paper deals with issues of shaping and functioning ofcomputer programs in the modelling and solving of multimoda Itransportation network problems. A methodology of an integrateduse of a programming language for mathematical modellingis defined, as well as spreadsheets for the solving of complexmultimodal transportation network problems. The papercontains a comparison of the partial and integral methods ofsolving multimodal transportation networks. The basic hypothesisset forth in this paper is that the integral method results inbetter multimodal transportation network rationalization effects,whereas a multimodal transportation network modelbased on the integral method, once built, can be used as the basisfor all kinds of transportation problems within multimodaltransport. As opposed to linear transport problems, multimodaltransport network can assume very complex shapes. This papercontains a comparison of the partial and integral approach totransp01tation network solving. In the partial approach, astraightforward model of a transp01tation network, which canbe solved through the use of the Solver computer tool within theExcel spreadsheet inteiface, is quite sufficient. In the solving ofa multimodal transportation problem through the integralmethod, it is necessmy to apply sophisticated mathematicalmodelling programming languages which supp01t the use ofcomplex matrix functions and the processing of a vast amountof variables and limitations. The LINGO programming languageis more abstract than the Excel spreadsheet, and it requiresa certain programming knowledge. The definition andpresentation of a problem logic within Excel, in a manner whichis acceptable to computer software, is an ideal basis for modellingin the LINGO programming language, as well as a fasterand more effective implementation of the mathematical model.This paper provides proof for the fact that it is more rational tosolve the problem of multimodal transportation networks by

Spatial analysis of bus transport networks using network theory

Science.gov (United States)

Shanmukhappa, Tanuja; Ho, Ivan Wang-Hei; Tse, Chi Kong

2018-07-01

In this paper, we analyze the bus transport network (BTN) structure considering the spatial embedding of the network for three cities, namely, Hong Kong (HK), London (LD), and Bengaluru (BL). We propose a novel approach called supernode graph structuring for modeling the bus transport network. A static demand estimation procedure is proposed to assign the node weights by considering the points of interests (POIs) and the population distribution in the city over various localized zones. In addition, the end-to-end delay is proposed as a parameter to measure the topological efficiency of the bus networks instead of the shortest distance measure used in previous works. With the aid of supernode graph representation, important network parameters are analyzed for the directed, weighted and geo-referenced bus transport networks. It is observed that the supernode concept has significant advantage in analyzing the inherent topological behavior. For instance, the scale-free and small-world behavior becomes evident with supernode representation as compared to conventional or regular graph representation for the Hong Kong network. Significant improvement in clustering, reduction in path length, and increase in centrality values are observed in all the three networks with supernode representation. The correlation between topologically central nodes and the geographically central nodes reveals the interesting fact that the proposed static demand estimation method for assigning node weights aids in better identifying the geographically significant nodes in the network. The impact of these geographically significant nodes on the local traffic behavior is demonstrated by simulation using the SUMO (Simulation of Urban Mobility) tool which is also supported by real-world empirical data, and our results indicate that the traffic speed around a particular bus stop can reach a jammed state from a free flow state due to the presence of these geographically important nodes. A comparison

Gas Transport and Exchange through Wetland Plant Aerenchyma

DEFF Research Database (Denmark)

Sorrell, Brian Keith; Brix, Hans

2013-01-01

Aerenchyma, the large airspaces in aquatic plants, is a rapid gas transport pathway between atmosphere and soil in wetlands. Oxygen transport aerates belowground tissue and oxidizes rhizosphere soil, an important process in wetland biogeochemistry. Most plant O2 transport occurs by diffusion...

Optimising Transport in a Homogeneous Network

OpenAIRE

WEAIRE, DENIS LAWRENCE

2004-01-01

PUBLISHED Many situations in physics, biology, and engineering consist of the transport of some physical quantity through a network of narrow channels. The ability of a network to transport such a quantity in every direction can be described by the average conductivity associated with it. When the flow through each channel is conserved and derives from a potential function, we show that there exists an upper bound of the average conductivity and explicitly give the expression f...

Optimizing transport in a homogeneous network

OpenAIRE

WEAIRE, DENIS LAWRENCE

2004-01-01

PUBLISHED Many situations in physics, biology, and engineering consist of the transport of some physical quantity through a network of narrow channels. The ability of a network to transport such a quantity in every direction can be described by the average conductivity associated with it. When the flow through each channel is conserved and derives from a potential function, we show that there exists an upper bound of the average conductivity and explicitly give the expression f...

Natural gas in road transport in New Zealand

Energy Technology Data Exchange (ETDEWEB)

Maiden, C J

1986-01-01

This paper describes how the products of New Zealand's natural gas fields are to be used in the transport sector to reduce oil imports. As a result of such developments New Zealand will be about 53% self-sufficient in transport fuels in 1986/1987. This self-sufficiency will be made up as follows: 25% from condensate from gas fields, 18% from synthetic gasoline, 5% from the use of compressed natural gas (CNG) and liquefied petroleum gas (LPT) in vehicles and 5% from indigenous oil supplies. History and status of the CNG Programme are outlined. Government has set a goal of 200,000 vehicles operating on CNG by 1990 and, at present, about 80,000 vehicles are powered by natural gas. The Gas to Gasoline project is described in some detail. New Zealand's imports of crude oil and oil products for 1986/1987 are forecast to total 1,900,000 tonnes, less than one-half of the 4,257,000 tonnes of comparable imports in 1973/1974.

Strategic regulation of gas transport

International Nuclear Information System (INIS)

Nese, Gjermund; Straume, Odd Rune

2005-02-01

The basis of the article has been the growing focus on competition within the natural gas markets particularly in the EU. Increased competition whether upstream or downstream may influence the distribution of profit between producing and consuming countries. For Norway as a large exporter of natural gas to the European market this would be an important problem. The chain of values in the gas market consists of three complementary parts (production, problem definition and distribution). With this in mind it is studied how the countries would use strategic availability pricing for transport and distribution systems for moving as large a part of the total profit as possible to the parts of the chain of value they control themselves. The focus has been on how increased competition in the market for natural gas influence the authority incentives for stipulating a high or low availability price and to what extent increased competition influence the welfare level in the producing and consuming countries when they use strategic availability pricing. The analysis builds on a theoretical model developed by the company Nese and Straume (2005). Finally some of the more interesting results as to the Norwegian position as a gas producer are presented. One of the more surprising results was that for an exporting country and an importing country increased competition upwards may be an advantage for the exporting country while negative for the importing country. The result was valid also when a competing export country was included when this country did not use strategic availability pricing. If the competing country also acted strategically the result inverted. However, if the gas exporting countries were capable of perfect coordination of their availability pricing the case would revert to the situation with only one exporting country and the result would be valid. If a future formation of a ''gas-OPEC'' is considered where for example Norway and Russia cooperate in a gas

The redefinition of the american and british gas industries: the regulation of the access load to the gas pipelines networks; La restructuration des industries gazieres americaine et britannique: la reglementation de la charge d'acces aux reseaux de gazoducs

Energy Technology Data Exchange (ETDEWEB)

David, L

2000-10-01

The transport and distribution networks regulation is the main stakes of the regulation reform of the gas industries. This thesis analyzes the models applied in The Usa and in the United Kingdom. The first part deals with the gas industries deregulation in these two countries, the impacts on the economy and the organization of the gas industries. The second part presents a theoretical approach of the regulation applied to the prices of the natural ags transport by gas pipelines. Regulation by the service cost price and by price cap are compared. (A.L.B.)

Ben Macdhui High Altitude Trace Gas and Aerosol Transport Experiment

CSIR Research Space (South Africa)

Piketh, SJ

1999-01-01

Full Text Available The Ben Macdhui High Altitude Aerosol and Trace Gas Transport Experiment (BHATTEX) was started to characterize the nature and magnitude of atmospheric, aerosol and trace gas transport paths recirculation over and exiting from southern Africa...

T-SDN architecture for space and ground integrated optical transport network

Science.gov (United States)

Nie, Kunkun; Hu, Wenjing; Gao, Shenghua; Chang, Chengwu

2015-11-01

Integrated optical transport network is the development trend of the future space information backbone network. The space and ground integrated optical transport network(SGIOTN) may contain a variety of equipment and systems. Changing the network or meeting some innovation missions in the network will be an expensive implement. Software Defined Network(SDN) provides a good solution to flexibly adding process logic, timely control states and resources of the whole network, as well as shielding the differences of heterogeneous equipment and so on. According to the characteristics of SGIOTN, we propose an transport SDN architecture for it, with hierarchical control plane and data plane composed of packet networks and optical transport networks.

Shippers and Network Capacity Booking in the Dutch Gas Market

NARCIS (Netherlands)

Bucura, C.; Lukszo, Z.

2012-01-01

The main objectives of the Third Gas Directive (2009/73EC) approved by the European Union are: unbundling, creating an independent Transport Service Operator (TSO) and ensuring free access to the market. The separation of gas trading from transportation activities required new market rules and gas

Gas transport in low-permeability formations: a review of experimental evidence and modeling approaches

International Nuclear Information System (INIS)

Marschall, Paul; Keller, Lukas; Lanyon, Bill; Senger, Rainer

2012-01-01

This paper presents a review of phenomenological studies on immiscible fluid flow in porous media, clarifies terminology as used by different disciplines and discusses the different modeling approaches. It concludes with a discussion on the transferability of classical two-phase flow concepts on gas transport processes in low-permeability clay-stones. From a phenomenological point of view, advection and diffusion of dissolved species represent the simplest transport mechanisms in a water-saturated porous medium. The propagation of the dissolved species is controlled by the water velocity and its extent is controlled by the hydrodynamic dispersion - a well-known aggregate representation of the mixing processes due to diffusion, Taylor dispersion and tortuosity. Usually, the dissolution of a gaseous species in water is described by Henry's law, the diffusion of the dissolved gas is represented by Fick's law and the viscous losses of the pore water flow in the pore network are expressed by Darcy's law. Two-phase flow conditions occur when gas invades as a separate phase a water-saturated porous medium. This process is often called drainage, because the non-wetting fluid (gas) displaces a wetting fluid (pore water, 'defending' fluid). The propagation of the gas front is controlled by the complex interaction of gravity, viscous forces and capillary forces. Lenormand et al. (1988) conducted two-phase flow experiments for a wide range of capillary numbers Ca and viscosity ratios M. They identified 3 major flow regimes in the C a -M-space, which they coined viscous fingering, capillary fingering and stable displacement. The regime of stable displacement applies for the special case where the invading fluid has a higher viscosity than the defending fluid (e.g. water imbibition in a gas-filled porous medium). Viscous and capillary fingering are associated with instable displacement of a wetting fluid by the non-wetting fluid, giving rise to phenomena such as migration

Long-term transport network 2008-2017 investment forecast plan

International Nuclear Information System (INIS)

2008-01-01

Total Infrastructure Gaz France (TIGF) provides and develops natural gas transport and storage services on a European scale to meet its customers' needs. It achieves a turnover of almost 300 million Euros and employs some 370 people. Backed by 50 years of expertise, TIGF is a major player in the natural gas market in 15 departements in South-West France. TIGF has drawn up an indicative development plan for the network for 2008-2017. This document gives an overview of proposed investments and of the development of transport services provided by TIGF, responding to changes in the gas market, the shippers' growing need for transport capacity and the forecast growth in gas consumption in the TIGF area (proposed CCGT gas fired power stations). Investment in gas infrastructure is a major step forward towards assuring the development of a competitive market that is fair, transparent and non-discriminatory for the years to come. That is why TIGF is focussing its development in the coming years on increasing the fluidity of transits entering/leaving its area. As the gas market is currently in a state of continuous change, and major uncertainties hang over the needs of the various players particularly over exchanges with the area to the north of TIGF, with Spain and the installation of a methane terminal at Verdon. In this uncertain climate, TIGF will focus on developing the WEST corridor for the next 5 years (2008- 2013), to provide reversibility of flows between France and Spain. This will cover the following works: the LACAL pipeline (Lacq-Calahorra), the Bearn Pipeline Artery (Lussagnet - Lacq), increased capacity on the Guyenne Pipeline Artery and on the EUSKADOUR pipeline (Coudure - Arcangues). This pipeline corridor, on which TIGF's development work started in 2007, is currently the one at the most advanced stage. For the next few years it will become the sole exchange hub between northern Spain and southern France. Beyond 2013, depending on market developments, TIGF

Natural gas distribution network of Lima and Callao, Peru

Energy Technology Data Exchange (ETDEWEB)

Maroye, Stephane; Aerssens, Andre [Tractebel Engineering, Lima (Peru)

2005-07-01

In May 2002, Suez-Tractebel was awarded by the government of Peru a 30-year concession for the construction and operation of the gas distribution network in Lima, Peru. On 10 July, 2004, first gas was delivered to Lima, 1 month ahead of the official date. This gas distribution network, operated by GNLC (Gas Natural de Lima y Callao), delivers gas to some of the largest industries and power generators in and around Lima and the harbour area of Callao. Gas delivered in Lima comes through a 700 km HP gas pipeline from Camisea fields. This pipeline is operated by TGP (Transportadora de Gas del Peru). A City Gate is located at Lurin, on the southern side of the city. The gas distribution network is made of a 62 km main pipeline (20') with 25 km laterals. The main pipeline is operated at 50 bar, as the main customer, the Etevensa power plant, is located on the northern side of the city. Due to this high operating pressure combined to the surroundings, specific design philosophies were adopted to meet the extreme safety requirements. This paper highlights the specific measures taken during construction phase and the experience of the first months of operation of this challenging project. (author)

Optimal design of a gas transmission network: A case study of the Turkish natural gas pipeline network system

Science.gov (United States)

Gunes, Ersin Fatih

Turkey is located between Europe, which has increasing demand for natural gas and the geographies of Middle East, Asia and Russia, which have rich and strong natural gas supply. Because of the geographical location, Turkey has strategic importance according to energy sources. To supply this demand, a pipeline network configuration with the optimal and efficient lengths, pressures, diameters and number of compressor stations is extremely needed. Because, Turkey has a currently working and constructed network topology, obtaining an optimal configuration of the pipelines, including an optimal number of compressor stations with optimal locations, is the focus of this study. Identifying a network design with lowest costs is important because of the high maintenance and set-up costs. The quantity of compressor stations, the pipeline segments' lengths, the diameter sizes and pressures at compressor stations, are considered to be decision variables in this study. Two existing optimization models were selected and applied to the case study of Turkey. Because of the fixed cost of investment, both models are formulated as mixed integer nonlinear programs, which require branch and bound combined with the nonlinear programming solution methods. The differences between these two models are related to some factors that can affect the network system of natural gas such as wall thickness, material balance compressor isentropic head and amount of gas to be delivered. The results obtained by these two techniques are compared with each other and with the current system. Major differences between results are costs, pressures and flow rates. These solution techniques are able to find a solution with minimum cost for each model both of which are less than the current cost of the system while satisfying all the constraints on diameter, length, flow rate and pressure. These results give the big picture of an ideal configuration for the future state network for the country of Turkey.

Network Performance Improvement under Epidemic Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2013-01-01

In this paper we investigate epidemic failure spreading in large- scale GMPLS-controlled transport networks. By evaluating the effect of the epidemic failure spreading on the network, we design several strategies for cost-effective network performance improvement via differentiated repair times....... First we identify the most vulnerable and the most strategic nodes in the network. Then, via extensive simulations we show that strategic placement of resources for improved failure recovery has better performance than randomly assigning lower repair times among the network nodes. Our OPNET simulation...... model can be used during the network planning process for facilitating cost- effective network survivability design....

Gas Transport Services. West European Gas Transmission Tariff Comparisons

International Nuclear Information System (INIS)

2006-07-01

Since 1999, the Dutch gas transmission company, Gastransport Services (GTS), has commissioned an independent consultant to prepare reports comparing gas transportation tariffs across Western Europe on an annual basis. This report describes the tariffs in force at 1 February 2006. The previous report was published in May 2005, and reported on the tariffs which were in force at 1 January 2005. Since then several companies have published revised carriage arrangements, or have adjusted their tariffs (e.g. to reflect inflation, or for other reasons). In this report we compare the GTS tariff with the transportation tariffs in eleven other countries: Austria, Belgium, Denmark, France, Germany, Ireland, Italy, Luxembourg, Spain, Sweden, and the United Kingdom. This means that all West European countries with Third Party Access to gas transmission systems (except Finland) are covered in this report. In this main part of the report, we concentrate on showing charts which illustrate the comparisons of tariffs, at various distances, volumes and load factors. This gives an overall picture of the tariffs offered by each company, rather than concentrating on particular cases. The detailed calculations for each of the 45 cases are shown in the Appendix to this report, and the conclusions from the cases are shown in a colour-coded chart in the Summary and Conclusions.

Towards Optimal Transport Networks

Directory of Open Access Journals (Sweden)

Erik P. Vargo

2010-08-01

Full Text Available Our ultimate goal is to design transportation net- works whose dynamic performance metrics (e.g. pas- senger throughput, passenger delay, and insensitivity to weather disturbances are optimized. Here the fo- cus is on optimizing static features of the network that are known to directly affect the network dynamics. First, we present simulation results which support a connection between maximizing the first non-trivial eigenvalue of a network's Laplacian and superior air- port network performance. Then, we explore the ef- fectiveness of a tabu search heuristic for optimizing this metric by comparing experimental results to the- oretical upper bounds. We also consider generating upper bounds on a network's algebraic connectivity via the solution of semidefinite programming (SDP relaxations. A modification of an existing subgraph extraction algorithm is implemented to explore the underlying regional structures in the U.S. airport net- work, with the hope that the resulting localized struc- tures can be optimized independently and reconnected via a "backbone" network to achieve superior network performance.

Gas transportation issues in the WCSB

International Nuclear Information System (INIS)

Turner, M.

1998-01-01

This paper addressed the issue of the competitiveness of the Western Canadian Sedimentary Basin (WCSB), concentrating on transportation issues. Various related issues such as natural gas pricing dynamics, price convergence in late 1998, projected gas revenues, issues of supply and demand, reserves inventory, the worrisome rate of decline in well productivity, deliverability and drilling, all received attention. Despite the gloomy picture, the general conclusion was that industry activity in the Basin will need to increase as the growth of the WCSB will be driven by rising North American demand. A profile of Nova Gas Transmission Ltd. was also presented. 1 tab., 13 figs

Effect of air turbulence on gas transport in soil; comparison of approaches

Science.gov (United States)

Pourbakhtiar, Alireza; Papadikis, Konstantinos; Poulsen, Tjalfe; Bridge, Jonathan; Wilkinson, Stephen

2017-04-01

Greenhouse gases are playing the key role in global warming. Soil is a source of greenhouse gases such as methane (CH4). Radon (Rn) which is a radioactive gas can emit form subsurface into the atmosphere and leads to health concerns in urban areas. Temperature, humidity, air pressure and vegetation of soil can affect gas emissions inside soil (Oertel et al., 2016). It's shown in many cases that wind induced fluctuations is an important factor in transport of gas through soil and other porous media. An example is: landfill gas emissions (Poulsen et al., 2001). We applied an experimental equipment for measuring controlled air turbulence on gas transport in soil in relation to the depth of sample. Two approaches for measurement of effect of wind turbulence on gas transport were applied and compared. Experiments were carried out with diffusion of CO2 and air as tracer gases with average vertical wind speeds of 0 to 0.83 m s-1. In approach A, Six different sample thicknesses from 5 to 30 cm were selected and total of 4 different wind conditions with different speed and fluctuations were applied. In approach B, a sample with constant depth was used. Five oxygen sensors were places inside sample at different depths. Total of 111 experiments were carried out. Gas transport is described by advection-dispersion equation. Gas transport is quantified as a dispersion coefficient. Oxygen breakthrough curves as a function of distance to the surface of the sample exposed to wind were derived numerically with an explicit forward time, central space finite-difference based model to evaluate gas transport. We showed that wind turbulence-induced fluctuations is an important factor in gas transport that can increase gas transport with average of 45 times more than molecular diffusion under zero wind condition. Comparison of two strategies for experiments, indicated that, constant deep samples (Approach B) are more reliable for measurement of gas transport under influence of wind

Natural gas network resiliency to a "shakeout scenario" earthquake.

Energy Technology Data Exchange (ETDEWEB)

Ellison, James F.; Corbet, Thomas Frank,; Brooks, Robert E.

2013-06-01

A natural gas network model was used to assess the likely impact of a scenario San Andreas Fault earthquake on the natural gas network. Two disruption scenarios were examined. The more extensive damage scenario assumes the disruption of all three major corridors bringing gas into southern California. If withdrawals from the Aliso Canyon storage facility are limited to keep the amount of stored gas within historical levels, the disruption reduces Los Angeles Basin gas supplies by 50%. If Aliso Canyon withdrawals are only constrained by the physical capacity of the storage system to withdraw gas, the shortfall is reduced to 25%. This result suggests that it is important for stakeholders to put agreements in place facilitating the withdrawal of Aliso Canyon gas in the event of an emergency.

Power stabilized CO2 gas transport laser

International Nuclear Information System (INIS)

Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

1975-01-01

The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

Performance verification of network function virtualization in software defined optical transport networks

Science.gov (United States)

Zhao, Yongli; Hu, Liyazhou; Wang, Wei; Li, Yajie; Zhang, Jie

2017-01-01

With the continuous opening of resource acquisition and application, there are a large variety of network hardware appliances deployed as the communication infrastructure. To lunch a new network application always implies to replace the obsolete devices and needs the related space and power to accommodate it, which will increase the energy and capital investment. Network function virtualization1 (NFV) aims to address these problems by consolidating many network equipment onto industry standard elements such as servers, switches and storage. Many types of IT resources have been deployed to run Virtual Network Functions (vNFs), such as virtual switches and routers. Then how to deploy NFV in optical transport networks is a of great importance problem. This paper focuses on this problem, and gives an implementation architecture of NFV-enabled optical transport networks based on Software Defined Optical Networking (SDON) with the procedure of vNFs call and return. Especially, an implementation solution of NFV-enabled optical transport node is designed, and a parallel processing method for NFV-enabled OTN nodes is proposed. To verify the performance of NFV-enabled SDON, the protocol interaction procedures of control function virtualization and node function virtualization are demonstrated on SDON testbed. Finally, the benefits and challenges of the parallel processing method for NFV-enabled OTN nodes are simulated and analyzed.

Transport coefficients of a dissociating gas

International Nuclear Information System (INIS)

Lebed', I.V.

1987-01-01

The calculation of the transport coefficients of a dissociating gas involves fundamental difficulties which arise when the internal degrees of freedom of the molecules are taken strictly into account. In practical calculations extensive use is made of the approximation in the context of which the dependence of a diffusion velocity of the molecule on its internal state is totally neglected. In this case the expressions for the stress tensor and the diffusion velocities coincide with the corresponding expressions for a mixture of structureless particles; in the expression for the heat flux the diffusion transport of internal energy is taken only approximately into account. Here, analytic expressions for the diffusion velocities, heat flux and stress tensor are obtained without introducing simplifying assumptions. The calculation method is based on an approximate method of calculating the transport coefficients of a multicomponent mixture of structureless particles. The relations obtained are analyzed and compared with the existing results; their accuracy is estimated. A closed system of equations of gas dynamics is presented for a number of cases of practical importance

Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

International Nuclear Information System (INIS)

Marschall, P.; Horseman, S.; Gimmi, T.

2005-01-01

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

Gas transport in the bentonite barrier of AGP and their interfaces; Transporte de gas en la barrera de bentonita de un AGP y sus interfases

Energy Technology Data Exchange (ETDEWEB)

Gutierrez Rodrigo, V.; Villar Gelicia, M. V.; Martin Martin, P. L.; Romero Alvarez, F. J.

2014-07-01

The research of gas transport processes through the barriers is of great relevance in the assessment of the behaviour of the repository. The main objective of this study is to determine the properties of gas transport in saturated bentonite samples and the interfaces between them. (Author)

Greenhouse Gas Emissions Trading for the Transport Sector

International Nuclear Information System (INIS)

Holmgren, Kristina; Belhaj, Mohammed; Gode, Jenny; Saernholm, Erik; Zetterberg, Lars; Aahman, Markus

2006-12-01

In this study we have analysed different options to apply emissions trading for greenhouse gas emissions to the transport sector. The main focus has been on the EU transport sector and the possibility to include it in the current EU ETS in the trading period beginning in 2013. The purpose was to study how different alternatives will affect different actors. Focus has been on three sub-sectors; road transport, aviation and shipping. The railway sector has only been treated on a general level. The study includes the following three parts: 1. An economic analysis of the consequences of greenhouse gas emissions trading for the transport sector including an analysis of how the total cost for reaching an emission target will be affected by an integrated emissions trading system for the transport sector and the industry (currently included sectors) compared to separate systems for the sectors, 2. An analysis of design possibilities for the different sub-sectors. Discussion of positive and negative aspects with different choices of design parameters, such as trading entity, covered greenhouse gases, allocation of emission allowances and monitoring systems, 3. Examination of the acceptance among different actors for different options of using greenhouse gas emissions trading in the transport sector. When setting up an emissions trading scheme there are a number of design parameters that have to be analysed in order to find an appropriate system, with limited administrative and transaction costs and as small distortions as possible to competitiveness

A Comparison of Geographic Information Systems, Complex Networks, and Other Models for Analyzing Transportation Network Topologies

Science.gov (United States)

Alexandrov, Natalia (Technical Monitor); Kuby, Michael; Tierney, Sean; Roberts, Tyler; Upchurch, Christopher

2005-01-01

This report reviews six classes of models that are used for studying transportation network topologies. The report is motivated by two main questions. First, what can the "new science" of complex networks (scale-free, small-world networks) contribute to our understanding of transport network structure, compared to more traditional methods? Second, how can geographic information systems (GIS) contribute to studying transport networks? The report defines terms that can be used to classify different kinds of models by their function, composition, mechanism, spatial and temporal dimensions, certainty, linearity, and resolution. Six broad classes of models for analyzing transport network topologies are then explored: GIS; static graph theory; complex networks; mathematical programming; simulation; and agent-based modeling. Each class of models is defined and classified according to the attributes introduced earlier. The paper identifies some typical types of research questions about network structure that have been addressed by each class of model in the literature.

Novel gas sensors based on carbon nanotube networks

International Nuclear Information System (INIS)

Sayago, I; Aleixandre, M; Horrillo, M C; Fernandez, M J; Gutierrez, J; Terrado, E; Lafuente, E; Maser, W K; Benito, A M; Martinez, M T; Munoz, E; Urriolabeitia, E P; Navarro, R

2008-01-01

Novel resistive gas sensors based on single-walled carbon nanotube (SWNT) networks as the active sensing element nave been investigated for gas detection. SWNTs networks were fabricated by airbrushing on alumina substrates. As-produced- and Pd-decorated SWNT materials were used as sensitive layers for the detection of NO 2 and H 2 , respectively. The studied sensors provided good response to NO 2 and H 2 as well as excellent selectivities to interfering gases.

Alaskan North Slope Oil & Gas Transportation Support

Energy Technology Data Exchange (ETDEWEB)

Lilly, Michael Russell [Geo-Watersheds Scientific LLC, Fairbanks, AK (United States)

2017-03-31

early or risk being caught on ice roads with flooded stream crossings, or unusable sections of ice road due to local melt. These challenges result in higher oil and gas field exploration and operational costs. Much of the scientific understanding to address transportation issues for oil and gas development on the North Slope exists, but has not been placed into a set of tools and data sets useful for industry and management agencies. Optimizing North Slope transportation networks during winter operation seasons is critical in managing increasing resource development and will provide a framework for environmentally-responsive development. Understanding the physical environment (such as snow, water, ice, soils) is necessary to ensure protection of fisheries and other natural resources on the sensitive tundra landscape. Solutions also have to do more than just describe current conditions, they need the ability to forecast short-term conditions. This will allow management agencies to respond to future variability in snow cover, soil temperature, and water availability more effectively. In turn, industry will then have more time to plan the significant mobilization taking place every winter season.

Positron transport: The plasma-gas interface

International Nuclear Information System (INIS)

Marler, J. P.; Petrovic, Z. Lj.; Bankovic, A.; Dujko, S.; Suvakov, M.; Malovic, G.; Buckman, S. J.

2009-01-01

Motivated by an increasing number of applications, new techniques in the analysis of electron transport have been developed over the past 30 years or so, but similar methods had yet to be applied to positrons. Recently, an in-depth look at positron transport in pure argon gas has been performed using a recently established comprehensive set of cross sections and well-established Monte Carlo simulations. The key novelty as compared to electron transport is the effect of positronium formation which changes the number of particles and has a strong energy dependence. This coupled with spatial separation by energy of the positron swarm leads to counterintuitive behavior of some of the transport coefficients. Finally new results in how the presence of an applied magnetic field affects the transport coefficients are presented.

Energy transition and transport networks, the Danish example. Breakfast-debate of 4 April 2013

International Nuclear Information System (INIS)

Boucly, Philippe; Dorte Riggelsen, Anne; Lambert, Francois-Michel; Brabo, Torben; Bornard, Pierre

2013-01-01

This document contains contributions presented by the GRTgaz general manager, the Danish ambassador, an expert in circular economy, the vice-chairman of the Danish gas and electricity utility, and a high representative of RTE about the role of energy transport networks in energy transition. It appears that energy transition raises several issues for energy transport operators: technical challenges due to the growth of renewable energies (notably in terms of grid steering and of production and consumption peak management), the introduction of flexibility and development of energy storage means, mechanisms of solidarity between regions and countries, political and economic dimensions with exchanges on good practices

A sequential Monte Carlo model of the combined GB gas and electricity network

International Nuclear Information System (INIS)

Chaudry, Modassar; Wu, Jianzhong; Jenkins, Nick

2013-01-01

A Monte Carlo model of the combined GB gas and electricity network was developed to determine the reliability of the energy infrastructure. The model integrates the gas and electricity network into a single sequential Monte Carlo simulation. The model minimises the combined costs of the gas and electricity network, these include gas supplies, gas storage operation and electricity generation. The Monte Carlo model calculates reliability indices such as loss of load probability and expected energy unserved for the combined gas and electricity network. The intention of this tool is to facilitate reliability analysis of integrated energy systems. Applications of this tool are demonstrated through a case study that quantifies the impact on the reliability of the GB gas and electricity network given uncertainties such as wind variability, gas supply availability and outages to energy infrastructure assets. Analysis is performed over a typical midwinter week on a hypothesised GB gas and electricity network in 2020 that meets European renewable energy targets. The efficacy of doubling GB gas storage capacity on the reliability of the energy system is assessed. The results highlight the value of greater gas storage facilities in enhancing the reliability of the GB energy system given various energy uncertainties. -- Highlights: •A Monte Carlo model of the combined GB gas and electricity network was developed. •Reliability indices are calculated for the combined GB gas and electricity system. •The efficacy of doubling GB gas storage capacity on reliability of the energy system is assessed. •Integrated reliability indices could be used to assess the impact of investment in energy assets

Unconventional Gas. A Game Changer for Transport Too?

International Nuclear Information System (INIS)

Boncourt, Maite de

2011-01-01

A new technology trend, the development of natural gas vehicles, is emerging in the transport sector. While not new this technology is now being simultaneously revived by the discovery of significant amounts of unconventional gas, by the rise of oil prices, and by the decreased confidence in the sustainability of nuclear technology (and subsequent rising electricity prices in Europe). Natural gas could provide a path to a lower carbon intensive transport sector in both developed and developing countries. Gas is cheaper and less polluting than oil. It emits significantly less local pollutants than diesel and less CO 2 than gasoline. Historically present in Italy, South America, Iran and Pakistan natural gas vehicles are emerging in other countries: in some European countries, in the United States, in the Chinese provinces of Shaanxi and Henan, and in India. Asia and developing countries are expected to be responsible for a large share of the car market growth in the next years and consequently for a significant share of transport CO 2 emissions. The adoption of a given technology there could impact global markets and global CO 2 emissions significantly. While the trend is still loose, this paper responds to the possibility that this technology will expand: what would it imply? would it compete with the development of the electric vehicle? is it desirable? It appears that the advantages of natural gas vehicles are not as clear cut as they seem. Environmentally, they are beneficial only to countries with little -if no- CO 2 emissions standards. Several issues including the development of costly infrastructures are likely to raise costs. Natural gas vehicles development could also slow down the roll out of electric vehicles, hence delaying hopes of smoothing the integration of renewables into the power grid through the use of car batteries' storage capacity. But the main concern is the availability of cheap gas itself, on the basis of which this technology shift could

Network inter-connectivity and capacity reservation behaviour: an investigation of the Belgian gas transmission network

International Nuclear Information System (INIS)

Cuijpers, Ch.; Woitrin, D.

2009-01-01

Lack of cross-border integration explains largely why natural gas markets remain basically national in scope, with levels of concentration similarly high as when the liberalization process commenced. This paper presents the results of an assessment of the upstream/downstream capacity of the Belgian natural gas transmission network which is highly interconnected with adjacent networks and fosters important transit activities. It is shown that the tendency to a better market coupling still suffers from important mismatches of capacity provisions on both sides of cross-border interconnections. Moreover, shippers use gas transmission networks more and more from a commercial portfolio perspective which goes beyond the traditional security of supply purpose of network designs. Capacity booking rates appear to be significantly higher than the underlying physical gas flows. From these findings, the paper contributes to a better understanding of the market barrier created by contractual congestion at cross-border interconnection points. The paper argues that contractual congestion is a symptom of suboptimal cooperation of adjacent network operators and lack of effective mechanisms to bring booked but non-used capacity back to the market, rather than an indicator for an overall need to increase investment budgets. (authors)

Evaluating the transport in small-world and scale-free networks

International Nuclear Information System (INIS)

Juárez-López, R.; Obregón-Quintana, B.; Hernández-Pérez, R.; Reyes-Ramírez, I.; Guzmán-Vargas, L.

2014-01-01

We present a study of some properties of transport in small-world and scale-free networks. Particularly, we compare two types of transport: subject to friction (electrical case) and in the absence of friction (maximum flow). We found that in clustered networks based on the Watts–Strogatz (WS) model, for both transport types the small-world configurations exhibit the best trade-off between local and global levels. For non-clustered WS networks the local transport is independent of the rewiring parameter, while the transport improves globally. Moreover, we analyzed both transport types in scale-free networks considering tendencies in the assortative or disassortative mixing of nodes. We construct the distribution of the conductance G and flow F to evaluate the effects of the assortative (disassortative) mixing, finding that for scale-free networks, as we introduce different levels of the degree–degree correlations, the power-law decay in the conductances is altered, while for the flow, the power-law tail remains unchanged. In addition, we analyze the effect on the conductance and the flow of the minimum degree and the shortest path between the source and destination nodes, finding notable differences between these two types of transport

Transport link scanner: simulating geographic transport network expansion through individual investments

NARCIS (Netherlands)

Koopmans, C.C.; Jacobs, C.G.W.

2016-01-01

This paper introduces a GIS-based model that simulates the geographic expansion of transport networks by several decision-makers with varying objectives. The model progressively adds extensions to a growing network by choosing the most attractive investments from a limited choice set. Attractiveness

Structural and robustness properties of smart-city transportation networks

International Nuclear Information System (INIS)

Zhang Zhen-Gang; Ding Zhuo; Fan Jing-Fang; Chen Xiao-Song; Meng Jun; Ye Fang-Fu; Ding Yi-Min

2015-01-01

The concept of smart city gives an excellent resolution to construct and develop modern cities, and also demands infrastructure construction. How to build a safe, stable, and highly efficient public transportation system becomes an important topic in the process of city construction. In this work, we study the structural and robustness properties of transportation networks and their sub-networks. We introduce a complementary network model to study the relevance and complementarity between bus network and subway network. Our numerical results show that the mutual supplement of networks can improve the network robustness. This conclusion provides a theoretical basis for the construction of public traffic networks, and it also supports reasonable operation of managing smart cities. (rapid communication)

The network code

International Nuclear Information System (INIS)

1997-01-01

The Network Code defines the rights and responsibilities of all users of the natural gas transportation system in the liberalised gas industry in the United Kingdom. This report describes the operation of the Code, what it means, how it works and its implications for the various participants in the industry. The topics covered are: development of the competitive gas market in the UK; key points in the Code; gas transportation charging; impact of the Code on producers upstream; impact on shippers; gas storage; supply point administration; impact of the Code on end users; the future. (20 tables; 33 figures) (UK)

Integrated modeling for optimized regional transportation with compressed natural gas fuel

Directory of Open Access Journals (Sweden)

Hossam A. Gabbar

2016-03-01

Full Text Available Transportation represents major energy consumption where fuel is considered as a primary energy source. Recent development in the vehicle technology revealed possible economical improvements when using natural gas as a fuel source instead of traditional gasoline. There are several fuel alternatives such as electricity, which showed potential for future long-term transportation. However, the move from current situation where gasoline vehicle is dominating shows high cost compared to compressed natural gas vehicle. This paper presents modeling and simulation methodology to optimize performance of transportation based on quantitative study of the risk-based performance of regional transportation. Emission estimation method is demonstrated and used to optimize transportation strategies based on life cycle costing. Different fuel supply scenarios are synthesized and evaluated, which showed strategic use of natural gas as a fuel supply.

Planning the network of gas pipelines through modeling tools

Energy Technology Data Exchange (ETDEWEB)

Sucupira, Marcos L.L.; Lutif Filho, Raimundo B. [Companhia de Gas do Ceara (CEGAS), Fortaleza, CE (Brazil)

2009-07-01

Natural gas is a source of non-renewable energy used by different sectors of the economy of Ceara. Its use may be industrial, residential, commercial, as a source of automotive fuel, as a co-generation of energy and as a source for generating electricity from heat. For its practicality this energy has a strong market acceptance and provides a broad list of clients to fit their use, which makes it possible to reach diverse parts of the city. Its distribution requires a complex network of pipelines that branches throughout the city to meet all potential clients interested in this source of energy. To facilitate the design, analysis, expansion and location of bottlenecks and breaks in the distribution network, a modeling software is used that allows the network manager of the net to manage the various information about the network. This paper presents the advantages of modeling the gas distribution network of natural gas companies in Ceara, showing the tool used, the steps necessary for the implementation of the models, the advantages of using the software and the findings obtained with its use. (author)

Resilience of natural gas networks during conflicts, crises and disruptions.

Directory of Open Access Journals (Sweden)

Rui Carvalho

Full Text Available Human conflict, geopolitical crises, terrorist attacks, and natural disasters can turn large parts of energy distribution networks offline. Europe's current gas supply network is largely dependent on deliveries from Russia and North Africa, creating vulnerabilities to social and political instabilities. During crises, less delivery may mean greater congestion, as the pipeline network is used in ways it has not been designed for. Given the importance of the security of natural gas supply, we develop a model to handle network congestion on various geographical scales. We offer a resilient response strategy to energy shortages and quantify its effectiveness for a variety of relevant scenarios. In essence, Europe's gas supply can be made robust even to major supply disruptions, if a fair distribution strategy is applied.

Water vapor and Gas Transport through Polymeric Membranes

NARCIS (Netherlands)

Metz, S.J.

2003-01-01

Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

Probabilistic modelling of security of supply in gas networks and evaluation of new infrastructure

International Nuclear Information System (INIS)

Praks, Pavel; Kopustinskas, Vytis; Masera, Marcelo

2015-01-01

The paper presents a probabilistic model to study security of supply in a gas network. The model is based on Monte-Carlo simulations with graph theory, and is implemented in the software tool ProGasNet. The software allows studying gas networks in various aspects including identification of weakest links and nodes, vulnerability analysis, bottleneck analysis, evaluation of new infrastructure etc. In this paper ProGasNet is applied to a benchmark network based on a real EU gas transmission network of several countries with the purpose of evaluating the security of supply effects of new infrastructure, either under construction, recently completed or under planning. The probabilistic model enables quantitative evaluations by comparing the reliability of gas supply in each consuming node of the network. - Highlights: • A Monte-Carlo algorithm for stochastic flow networks is presented. • Network elements can fail according to a given probabilistic model. • Priority supply pattern of gas transmission networks is assumed. • A real-world EU gas transmission network is presented and analyzed. • A risk ratio is used for security of supply quantification of a new infrastructure.

Inventory theory, mode choice and network structure in freight transport

NARCIS (Netherlands)

Combes, F.; Tavasszy, L.A.

2016-01-01

In passenger transport, hub-and-spoke networks allow the transportation of small passenger flows with competitive frequencies, in a way that direct line networks cannot. Equivalently, in freight transport, it can be expected that small shipper-receiver flows of high added value commodities transit

Node-node correlations and transport properties in scale-free networks

Science.gov (United States)

Obregon, Bibiana; Guzman, Lev

2011-03-01

We study some transport properties of complex networks. We focus our attention on transport properties of scale-free and small-world networks and compare two types of transport: Electric and max-flow cases. In particular, we construct scale-free networks, with a given degree sequence, to estimate the distribution of conductances for different values of assortative/dissortative mixing. For the electric case we find that the distributions of conductances are affect ed by the assortative mixing of the network whereas for the max-flow case, the distributions almost do not show changes when node-node correlations are altered. Finally, we compare local and global transport in terms of the average conductance for the small-world (Watts-Strogatz) model

2006 statistical data of the French gas industry

International Nuclear Information System (INIS)

2007-12-01

This document makes a synthesis of the 2006 results of the annual inquiry about the French natural gas industry: 1 - organization of the French gas market (production, transport, methane terminals, storage facilities, distribution, commercialization, main steps of the opening of the gas market in France); 2 - the 2006 gas year (consumption, imports, production, stockpiles); 3 - results of the 2006 inquiry: infrastructures (storage capacities, pipelines and distribution network), production (evolution of natural gas and industrial gases production, uses), transport (inputs and outputs, geographical origin of inputs in 2005 and 2006, raw imports evolution since 1973), storage (evolution of stockpiles variation), natural gas supplies (sectoral uses), supplies by region and by sector in 2006, consumption by sector; 4 - power generation by gas cogeneration in 2005 (plants characteristics, classification, cogeneration status (in TWh), regional distribution of plants); 5 - 2006 monthly changes (inputs, net imports, consumption and useful stockpile, consumption and net imports); 6 - international comparisons (gas share in the overall energy consumption, consumption per user, evolution of main sectors of consumption in some European countries since 1973); 7 - appendixes: French transportation network, main gas roads in Europe, European gas fluxes, 2006 energy status, gas statuses during the past three years. (J.S.)

Literature Review and Synthesis for the Natural Gas Infrastructure

Energy Technology Data Exchange (ETDEWEB)

Folga, Stephen [Argonne National Lab. (ANL), Argonne, IL (United States); Talaber, Leah [Argonne National Lab. (ANL), Argonne, IL (United States); McLamore, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Kraucunas, Ian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McPherson, Timothy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parrott, Lori [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Manzanares, Trevor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-06-01

The efficient and effective movement of natural gas from producing regions to consuming regions requires an extensive and elaborate transportation system. In many instances, natural gas produced from a particular well has to travel a great distance to reach its point of use. The transportation system for natural gas consists of a complex network of pipelines designed to quickly and efficiently transport the gas from its origin to areas of high demand. The transportation of natural gas is closely linked to its storage: If the natural gas being transported is not immediately required, it can be put into storage facilities until it is needed. A description of the natural gas transmission, storage, and distribution (TS&D) sector is provided as follows.

Gas market distorting effects of imbalanced gas balancing rules: Inefficient regulation of pipeline flexibility

International Nuclear Information System (INIS)

Keyaerts, Nico; Hallack, Michelle; Glachant, Jean-Michel; D'haeseleer, William

2011-01-01

This paper analyzes the value and cost of line-pack flexibility in liberalized gas markets through examination of the techno-economic characteristics of gas transport pipelines and the trade-offs between different ways to use the infrastructure: transport and flexibility. Line-pack flexibility is becoming increasingly important as a tool to balance gas supply and demand over different periods. In the European liberalized market context, a monopolist unbundled network operator offers regulated transport services and flexibility (balancing) services according to the network code and balancing rules. Therefore, gas policy makers should understand the role and consequences of line-pack regulation. The analysis shows that the line-pack flexibility service has an important economic value for the shippers and the TSO. Furthermore, the analysis identifies distorting effects in the gas market due to inadequate regulation of line-pack flexibility: by disregarding the sunk costs of flexibility in the balancing rules, the overall efficiency of the gas system is decreased. Finally, the analysis demonstrates that the actual costs of line-pack flexibility are related to the peak cumulative imbalance throughout the balancing period. Any price for pipeline flexibility should, therefore, be based on the related trade-off between the right to use the line-pack flexibility and the provision of transport services. - Research Highlights: →Line-pack flexibility is a main gas balancing instrument. →Capacity related costs of line-pack flexibility depend on peak cumulative imbalances. →Line-pack pricing rules determine choice between ex ante and ex post balancing. →Inefficient line-pack regulation causes gas market distortions.

Development scheme for the public electricity transport network - 2006-2020

International Nuclear Information System (INIS)

2006-01-01

After having discussed the role of the development scheme and its mains requirements, presented its important components (energy needs, energy transport needs), and described its elaboration mode, this report gives an overview of the present status of the electricity transport network in France: 400.000 volts transport and interconnection networks, 225.000 volts and high voltage networks, development objectives, development context, transport network characteristics in 2006 (country gridding, development dynamics and consumption growth). Then, it presents a set of hypotheses about consumption, production and European exchanges. It identifies different types of constraints (customer connection, supply safety, electric and economic performance, robustness against extreme climate phenomena) and presents a method to assess these constraints (simulation of situations at risk, supply quality analysis, works expertise). The last part present the middle- and long-term constraints for the network

Network optimization including gas lift and network parameters under subsurface uncertainty

Energy Technology Data Exchange (ETDEWEB)

Schulze-Riegert, R.; Baffoe, J.; Pajonk, O. [SPT Group GmbH, Hamburg (Germany); Badalov, H.; Huseynov, S. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE; Trick, M. [SPT Group, Calgary, AB (Canada)

2013-08-01

Optimization of oil and gas field production systems poses a great challenge to field development due to complex and multiple interactions between various operational design parameters and subsurface uncertainties. Conventional analytical methods are capable of finding local optima based on single deterministic models. They are less applicable for efficiently generating alternative design scenarios in a multi-objective context. Practical implementations of robust optimization workflows integrate the evaluation of alternative design scenarios and multiple realizations of subsurface uncertainty descriptions. Production or economic performance indicators such as NPV (Net Present Value) are linked to a risk-weighted objective function definition to guide the optimization processes. This work focuses on an integrated workflow using a reservoir-network simulator coupled to an optimization framework. The work will investigate the impact of design parameters while considering the physics of the reservoir, wells, and surface facilities. Subsurface uncertainties are described by well parameters such as inflow performance. Experimental design methods are used to investigate parameter sensitivities and interactions. Optimization methods are used to find optimal design parameter combinations which improve key performance indicators of the production network system. The proposed workflow will be applied to a representative oil reservoir coupled to a network which is modelled by an integrated reservoir-network simulator. Gas-lift will be included as an explicit measure to improve production. An objective function will be formulated for the net present value of the integrated system including production revenue and facility costs. Facility and gas lift design parameters are tuned to maximize NPV. Well inflow performance uncertainties are introduced with an impact on gas lift performance. Resulting variances on NPV are identified as a risk measure for the optimized system design. A

The Spanish gas industry

International Nuclear Information System (INIS)

Anon.

1993-01-01

The spanish gas industry has become one of the major actors in the gas sector of the European Economic Community. This paper pictures the spanish gas industry on the basis of a study by Sedigas, the spanish member of the International Gas Union (IGU). The main subjects described are structure of gas companies, natural gas supply, transport and storage, natural gas distribution networks, statistical data on natural gas consumption, manufactured gas and Liquefied Petroleum Gases (LPG) production-consumption in Spain. 7 figs., 10 tabs

Micro/Nano-pore Network Analysis of Gas Flow in Shale Matrix.

Science.gov (United States)

Zhang, Pengwei; Hu, Liming; Meegoda, Jay N; Gao, Shengyan

2015-08-27

The gas flow in shale matrix is of great research interests for optimized shale gas extraction. The gas flow in the nano-scale pore may fall in flow regimes such as viscous flow, slip flow and Knudsen diffusion. A 3-dimensional nano-scale pore network model was developed to simulate dynamic gas flow, and to describe the transient properties of flow regimes. The proposed pore network model accounts for the various size distributions and low connectivity of shale pores. The pore size, pore throat size and coordination number obey normal distribution, and the average values can be obtained from shale reservoir data. The gas flow regimes were simulated using an extracted pore network backbone. The numerical results show that apparent permeability is strongly dependent on pore pressure in the reservoir and pore throat size, which is overestimated by low-pressure laboratory tests. With the decrease of reservoir pressure, viscous flow is weakening, then slip flow and Knudsen diffusion are gradually becoming dominant flow regimes. The fingering phenomenon can be predicted by micro/nano-pore network for gas flow, which provides an effective way to capture heterogeneity of shale gas reservoir.

Simulation of noise-assisted transport via optical cavity networks

International Nuclear Information System (INIS)

Caruso, Filippo; Plenio, Martin B.; Spagnolo, Nicolo; Vitelli, Chiara; Sciarrino, Fabio

2011-01-01

Recently, the presence of noise has been found to play a key role in assisting the transport of energy and information in complex quantum networks and even in biomolecular systems. Here we propose an experimentally realizable optical network scheme for the demonstration of the basic mechanisms underlying noise-assisted transport. The proposed system consists of a network of coupled quantum-optical cavities, injected with a single photon, whose transmission efficiency can be measured. Introducing dephasing in the photon path, this system exhibits a characteristic enhancement of the transport efficiency that can be observed with presently available technology.

Social networks, big data and transport planning

Energy Technology Data Exchange (ETDEWEB)

Ruiz Sanchez, T.; Lidon Mars Aicart, M. del; Arroyo Lopez, M.R.; Serna Nocedal, A.

2016-07-01

The characteristics of people who are related or tied to each individual affects her activitytravel behavior. That influence is especially associated to social and recreational activities, which are increasingly important. Collecting high quality data from those social networks is very difficult, because respondents are asked about their general social life, which is most demanding to remember that specific facts. On the other hand, currently there are different potential sources of transport data, which is characterized by the huge amount of information available, the velocity with it is obtained and the variety of format in which is presented. This sort of information is commonly known as Big Data. In this paper we identify potential sources of social network related big data that can be used in Transport Planning. Then, a review of current applications in Transport Planning is presented. Finally, some future prospects of using social network related big data are highlighted. (Author)

Topological Effects and Performance Optimization in Transportation Continuous Network Design

Directory of Open Access Journals (Sweden)

Jianjun Wu

2014-01-01

Full Text Available Because of the limitation of budget, in the planning of road works, increased efforts should be made on links that are more critical to the whole traffic system. Therefore, it would be helpful to model and evaluate the vulnerability and reliability of the transportation network when the network design is processing. This paper proposes a bilevel transportation network design model, in which the upper level is to minimize the performance of the network under the given budgets, while the lower level is a typical user equilibrium assignment problem. A new solution approach based on particle swarm optimization (PSO method is presented. The topological effects on the performance of transportation networks are studied with the consideration of three typical networks, regular lattice, random graph, and small-world network. Numerical examples and simulations are presented to demonstrate the proposed model.

Optimal urban networks via mass transportation

CERN Document Server

Buttazzo, Giuseppe; Stepanov, Eugene; Solimini, Sergio

2009-01-01

Recently much attention has been devoted to the optimization of transportation networks in a given geographic area. One assumes the distributions of population and of services/workplaces (i.e. the network's sources and sinks) are known, as well as the costs of movement with/without the network, and the cost of constructing/maintaining it. Both the long-term optimization and the short-term, "who goes where" optimization are considered. These models can also be adapted for the optimization of other types of networks, such as telecommunications, pipeline or drainage networks. In the monograph we study the most general problem settings, namely, when neither the shape nor even the topology of the network to be constructed is known a priori.

Acquisition management of the Global Transportation Network

Science.gov (United States)

2001-08-02

This report discusses the acquisition management of the Global transportation Network by the U.S. Transportation Command. This report is one in a series of audit reports addressing DoD acquisition management of information technology systems. The Glo...

Structural and robustness properties of smart-city transportation networks

Science.gov (United States)

Zhang, Zhen-Gang; Ding, Zhuo; Fan, Jing-Fang; Meng, Jun; Ding, Yi-Min; Ye, Fang-Fu; Chen, Xiao-Song

2015-09-01

The concept of smart city gives an excellent resolution to construct and develop modern cities, and also demands infrastructure construction. How to build a safe, stable, and highly efficient public transportation system becomes an important topic in the process of city construction. In this work, we study the structural and robustness properties of transportation networks and their sub-networks. We introduce a complementary network model to study the relevance and complementarity between bus network and subway network. Our numerical results show that the mutual supplement of networks can improve the network robustness. This conclusion provides a theoretical basis for the construction of public traffic networks, and it also supports reasonable operation of managing smart cities. Project supported by the Major Projects of the China National Social Science Fund (Grant No. 11 & ZD154).

Application of an entry-exit tariff model to the gas transport system in Spain

International Nuclear Information System (INIS)

Alonso, Alejandro; Serrano, Miguel; Olmos, Luis

2010-01-01

Under an entry-exit gas tariff system, reservation of capacity is split into entry capacity, to transport gas from the injection points to a virtual balancing point, and exit capacity, to transport gas from the balancing point to the exit points in the system. Entry-exit tariff for gas transport systems have been recommended by the 3rd EU Energy Package, since they are cost reflective, facilitate gas trade and can provide signals for the location of gas injections or off-takes. The advisability of applying an entry-exit tariff system is discussed in this paper. Apart from this, authors propose an entry-exit tariff model and apply it to compute charges for the Spanish gas transport system in 2009. Results produced by the model are presented as coefficients which should multiply the current postal transport tariff. The paper concludes that entry-exit tariffs would be useful location signals which would result in a better use of the gas transport system in Spain. In those cases where demand exceeds available capacity, as it occurs at the congested connection with France, entry-exit tariffs could be supplemented by capacity charges at entry points resulting from auctions. (author)

Offset Trace-Based Video Quality Evaluation Network Transport

DEFF Research Database (Denmark)

Seeling, P.; Reisslein, M.; Fitzek, Frank

2006-01-01

Video traces contain information about encoded video frames, such as frame sizes and qualities, and provide a convenient method to conduct multimedia networking research. Although wiedely used in networking research, these traces do not allow to determine the video qaulityin an accurate manner...... after networking transport that includes losses and delays. In this work, we provide (i) an overview of frame dependencies that have to be taken into consideration when working with video traces, (ii) an algorithmic approach to combine traditional video traces and offset distortion traces to determine...... the video quality or distortion after lossy network transport, (iii) offset distortion and quality characteristics and (iv) the offset distortion trace format and tools to create offset distortion traces....

Transport energy demand modeling of South Korea using artificial neural network

International Nuclear Information System (INIS)

Geem, Zong Woo

2011-01-01

Artificial neural network models were developed to forecast South Korea's transport energy demand. Various independent variables, such as GDP, population, oil price, number of vehicle registrations, and passenger transport amount, were considered and several good models (Model 1 with GDP, population, and passenger transport amount; Model 2 with GDP, number of vehicle registrations, and passenger transport amount; and Model 3 with oil price, number of vehicle registrations, and passenger transport amount) were selected by comparing with multiple linear regression models. Although certain regression models obtained better R-squared values than neural network models, this does not guarantee the fact that the former is better than the latter because root mean squared errors of the former were much inferior to those of the latter. Also, certain regression model had structural weakness based on P-value. Instead, neural network models produced more robust results. Forecasted results using the neural network models show that South Korea will consume around 37 MTOE of transport energy in 2025. - Highlights: → Transport energy demand of South Korea was forecasted using artificial neural network. → Various variables (GDP, population, oil price, number of registrations, etc.) were considered. → Results of artificial neural network were compared with those of multiple linear regression.

Trans-European transport networks and urban systems in European Union

Directory of Open Access Journals (Sweden)

Maksin-Mićić Marija

2003-01-01

Full Text Available The trans-European transport network has different effects at interregional macro-regional and mezzo-regional level, and its effectiveness rises at the lower regional levels. Possible approaches to the trans-European transport network impact and effect survey and policy options have been pointed out. In that respect the brief review of survies, strategic framework and policies in European Union has been given. The importance of increased accessibility and mobility for regional expansion and for more balanced and polycentric system of city networks has been underlined. The question is how the new major transport infrastructure affects the development of functional complementarity between cities and regions. The new trans-European or major transport infrastructure does not per se create regional and urban system network development, although it can affect the conditions for the processes that create growth and development. The effects can be increased by co-ordination of measures of regional and urban policy, land use, transport and other policies. The necessary measure is the introduction of spatial impact assessment as sectorial policy instrument for the large transport infrastructure projects.

Towards 100 gigabit carrier ethernet transport networks

DEFF Research Database (Denmark)

Rasmussen, Anders; Zhang, Jiang; Yu, Hao

2010-01-01

technology, making the use of Ethernet as a convergence layer for Next Generation Networks a distinct possibility. Triple Play services, in particular IPTV, are expected to be a main drivers for carrier Ethernet, however, a number of challenges must be addressed including QoS enabled control plane, enhanced......Ethernet as a transport technology has, up to now, lacked the features such as network layer architecture, customer separation and manageability that carriers require for wide-scale deployment. However, with the advent of PBB-TE and TMPLS, it is now possible to use Ethernet as a transport...

Report on the French gas market opening

International Nuclear Information System (INIS)

Syrota, J.

2002-10-01

This document takes stock on the french gas market opening since august 2000, implementation of the 98/30/CE directive and proposes recommendations on main questions of the future gas regulations. These questions concern the situation and forecast of the competition in Europe, the access tariffing to the transport networks and to the liquefied natural gas installations, the modalities of the network access for the third (ATR), the juridical aspects. (A.L.B.)

2003 statistics of the natural gas industry in France

International Nuclear Information System (INIS)

2004-12-01

This document synthesizes the main annual results for the French natural gas industry in 2003: 1 - introduction: consumption and supplies; 2 - methodology: production, transport, storage, distribution, definition of gases, information sources, reference documents, energy correspondences; 3 - Main data summarized in maps, graphics and tables: transport networks, storage, compression and production facilities; resources and employment; employment per sector of use; national production and imports; pipelines and distribution systems; personnel of the gas industry; sectoral distribution of gas supply networks; gas cogeneration: consumption, plants; monthly variation of imports and stocks; monthly variation of consumptions and stocks; regional supplies; regional and sectoral supplies; regional use of the national production; main 2003 status of the gas market; 2003 comparison between the inquiry and the provisional status; 2003 energy status. (J.S.)

Distribution forms for biogas and natural gas in Sweden

International Nuclear Information System (INIS)

Benjaminsson, Johan; Nilsson, Ronny

2009-11-01

Since biogas and natural gas basically have the same characteristics, they can be distributed in the same system. In the parts of the country where there is an extensive natural gas distribution network, the infrastructure for natural gas can be used for distribution of biogas. In order to increase the use of renewable energy, it is a political ambition to increase the share of biogas in the natural gas network, and, in the long run, entirely replace natural gas with biogas. Much of biogas production in the country is, however, not reached by the existing natural gas network, and this is also the case for a large part of the potential for future biogas production. In these areas the gas is transported in more or less extensive local gas distribution networks and by truck in compressed or liquid form. Transport of compressed and liquefied gas is efficient in some cases and development of these systems is an ongoing process. A number of facilities are planned for production of large quantities of biogas, several hundred GWh/year, through digestion and gasification processes. These plants will be located either in conjunction with major gas consumers or in the vicinity of the existing natural gas grid. The potential for biogas production is, however, present throughout the country and in order to meet market demand biogas requires efficient distribution systems

Strategy development management of Multimodal Transport Network

Directory of Open Access Journals (Sweden)

Nesterova Natalia S.

2016-01-01

Full Text Available The article gives a brief overview of works on the development of transport infrastructure for multimodal transportation and integration of Russian transport system into the international transport corridors. The technology for control of the strategy, that changes shape and capacity of Multi-modal Transport Network (MTN, is considered as part of the methodology for designing and development of MTN. This technology allows to carry out strategic and operational management of the strategy implementation based on the use of the balanced scorecard.

The Contribution of Natural Gas Vehicles to Sustainable Transport

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

The transport sector is currently responsible for 23% of energy-related CO2 emissions, and transport associated CO2 emissions will more than double by 2050. This working paper evaluates the potential costs and benefits of using natural gas as a vehicle fuel for road transportation, as well as the policy related to its market development.

Learning Traffic as Images: A Deep Convolutional Neural Network for Large-Scale Transportation Network Speed Prediction.

Science.gov (United States)

Ma, Xiaolei; Dai, Zhuang; He, Zhengbing; Ma, Jihui; Wang, Yong; Wang, Yunpeng

2017-04-10

This paper proposes a convolutional neural network (CNN)-based method that learns traffic as images and predicts large-scale, network-wide traffic speed with a high accuracy. Spatiotemporal traffic dynamics are converted to images describing the time and space relations of traffic flow via a two-dimensional time-space matrix. A CNN is applied to the image following two consecutive steps: abstract traffic feature extraction and network-wide traffic speed prediction. The effectiveness of the proposed method is evaluated by taking two real-world transportation networks, the second ring road and north-east transportation network in Beijing, as examples, and comparing the method with four prevailing algorithms, namely, ordinary least squares, k-nearest neighbors, artificial neural network, and random forest, and three deep learning architectures, namely, stacked autoencoder, recurrent neural network, and long-short-term memory network. The results show that the proposed method outperforms other algorithms by an average accuracy improvement of 42.91% within an acceptable execution time. The CNN can train the model in a reasonable time and, thus, is suitable for large-scale transportation networks.

Development of new process network for gas chromatograph and analyzers connected with SCADA system and Digital Control Computers at Cernavoda NPP Unit 1

International Nuclear Information System (INIS)

Deneanu, Cornel; Popa Nemoiu, Dragos; Nica, Dana; Bucur, Cosmin

2007-01-01

The continuous monitoring of gas mixture concentrations (deuterium/ hydrogen/oxygen/nitrogen) accumulated in 'Moderator Cover Gas', 'Liquid Control Zone' and 'Heat Transport D 2 O Storage Tank Cover Gas', as well as the continuous monitoring of Heavy Water into Light Water concentration in 'Boilers Steam', 'Boilers Blown Down', 'Moderator heat exchangers', and 'Recirculated Water System', sensing any leaks of Cernavoda NPP U1 led to requirement of developing a new process network for gas chromatograph and analyzers connected to the SCADA system and Digital Control Computers of Cernavoda NPP Unit 1. In 2005 it was designed and implemented the process network for gas chromatograph which connected the gas chromatograph equipment to the SCADA system and Digital Control Computers of the Cernavoda NPP Unit 1. Later this process network for gas chromatograph has been extended to connect the AE13 and AE14 Fourier Transform Infrared (FTIR) analyzers with either. The Gas Chromatograph equipment measures with best accuracy the mixture gases (deuterium/ hydrogen/oxygen/nitrogen) concentration. The Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers measure the Heavy Water into Light Water concentration in Boilers Steam, Boilers BlownDown, Moderator heat exchangers, and Recirculated Water System, monitoring and signaling any leaks. The Gas Chromatograph equipment and Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers use the new OPC (Object Link Embedded for Process Control) technologies available in ABB's VistaNet network for interoperability with automation equipment. This new process network has interconnected the ABB chromatograph and Fourier Transform Infrared analyzers with plant Digital Control Computers using new technology. The result was an increased reliability and capability for inspection and improved system safety

Feed gas contaminant control in ion transport membrane systems

Science.gov (United States)

Carolan, Michael Francis [Allentown, PA; Minford, Eric [Laurys Station, PA; Waldron, William Emil [Whitehall, PA

2009-07-07

Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

Natural gas power generation: interruptible gas distribution network regulation; Geracao termoeletrica a gas natural: regulacao do segmento interruptivel de distribuicao de gas canalizado

Energy Technology Data Exchange (ETDEWEB)

Paula, Claudio Paiva de; Kann, Zevi [Agencia Reguladora de Saneamento e Energia do Estado de Sao Paulo (ARSESP), SP (Brazil)

2008-07-01

The paper relates studies regarding the natural gas distribution network interruptible branch. This new service can be appropriate for thermal power generation on flexible dispatch mode, as 'take or pay' contracts surplus jobs. The paper indicates no regulatory restraints in an interruptible network implantation. The final conclusion is that interruptible contracts can be an improvement on the distribution business and certainly can accommodate a suitable demand and supply volumes in the long-term gas market balance. (author)

A microfluidic investigation of gas exsolution in glass and shale fracture networks

Science.gov (United States)

Porter, M. L.; Jimenez-Martinez, J.; Harrison, A.; Currier, R.; Viswanathan, H. S.

2016-12-01

Microfluidic investigations of pore-scale fluid flow and transport phenomena has steadily increased in recent years. In these investigations fluid flow is restricted to two-dimensions allowing for real-time visualization and quantification of complex flow and reactive transport behavior, which is difficult to obtain in other experimental systems. In this work, we describe a unique high pressure (up to 10.3 MPa) and temperature (up to 80 °C) microfluidics experimental system that allows us to investigate fluid flow and transport in geo-material (e.g., shale, Portland cement, etc.) micromodels. The use of geo-material micromodels allows us to better represent fluid-rock interactions including wettability, chemical reactivity, and nano-scale porosity at conditions representative of natural subsurface environments. Here, we present experimental results in fracture systems with applications to hydrocarbon mobility in fractured rocks. Complex fracture network patterns are derived from 3D x-ray tomography images of actual fractures created in shale rock cores. We use both shale and glass micromodels, allowing for a detailed comparison between flow phenomena in the different materials. We discuss results from two-phase gas (CO2 and N2) injection experiments designed to enhance oil recovery. In these experiments gas was injected into micromodels saturated with oil and allowed to soak for approximately 12 hours at elevated pressures. The pressure in the system was then decreased to atmospheric, causing the gas to expand and/or dissolve out of solution, subsequently mobilizing the oil. In addition to the experimental results, we present a relatively simple model designed to quantify the amount of oil mobilized as a function of decreasing system pressure. We will show comparisons between the experiments and model, and discuss the potential use of the model in field-scale reservoir simulations.

Generalized hydrodynamic transport in lattice-gas automata

Science.gov (United States)

Luo, Li-Shi; Chen, Hudong; Chen, Shiyi; Doolen, Gary D.; Lee, Yee-Chun

1991-01-01

The generalized hydrodynamics of two-dimensional lattice-gas automata is solved analytically in the linearized Boltzmann approximation. The dependence of the transport coefficients (kinematic viscosity, bulk viscosity, and sound speed) upon wave number k is obtained analytically. Anisotropy of these coefficients due to the lattice symmetry is studied for the entire range of wave number, k. Boundary effects due to a finite mean free path (Knudsen layer) are analyzed, and accurate comparisons are made with lattice-gas simulations.

Gasoline and other transportation fuels from natural gas in Canada

International Nuclear Information System (INIS)

Symons, E.A.; Miller, A.I.

1981-03-01

Ways in which natural gas might displace cude oil as a source of fuels for the Canadian transportation market are reviewed. Three approaches are possible: (1) direct use as compressed natural gas; (2)conversion of natural gas to methanol; and (3) further conversion of methanol to synthetic gasoline. (author)

Research on gas transport in chimneys: a progress report

International Nuclear Information System (INIS)

Hearst, J.R.

1986-01-01

The results of the AGRINI and TIERRA experiments have led us to study three general topics: collapse phenomenology, CO 2 content measurement, and gas transport in chimneys. Our results so far are fragmentary, but we have been able to come to some tentative conclusions: (1) a layer of strong material between depths of 24 and 32 m, and perhaps some relatively strong material deeper, may have caused the AGRINI crater shape. This layer was absent at the nearby LABAN and CROWDIE events. We were unable to locate the layer with a surface penetrometer or surface seismic methods, but it may be possible to measure strength vs depth in situ by examining the penetration depth of a projectile. (2) We can probably improve our knowledge of the in situ CO 2 content by calibrating a commercial carbon/oxygen logging system for NTS conditions. (3) It is possible to measure the response of the gas in a chimney to changes in atmospheric pressure. There can be significantly different gas transport in chimneys with the same pressure response, depending on the porosity and the distribution of the porosity. It is possible to perform an inexpensive experiment to study the gas transport in an existing chimney

Breakdown in traffic networks fundamentals of transportation science

CERN Document Server

Kerner, Boris S

2017-01-01

This book offers a detailed investigation of breakdowns in traffic and transportation networks. It shows empirically that transitions from free flow to so-called synchronized flow, initiated by local disturbances at network bottlenecks, display a nucleation-type behavior: while small disturbances in free flow decay, larger ones grow further and lead to breakdowns at the bottlenecks. Further, it discusses in detail the significance of this nucleation effect for traffic and transportation theories, and the consequences this has for future automatic driving, traffic control, dynamic traffic assignment, and optimization in traffic and transportation networks. Starting from a large volume of field traffic data collected from various sources obtained solely through measurements in real world traffic, the author develops his insights, with an emphasis less on reviewing existing methodologies, models and theories, and more on providing a detailed analysis of empirical traffic data and drawing consequences regarding t...

LOCATING HUBS IN TRANSPORT NETWORKS: AN ARTIFICIAL INTELLIGENCE APPROACH

OpenAIRE

Dušan Teodorović; Milica Šelmić; Ivana Vukićević

2014-01-01

Hub facilities serve as switching and transshipment points in transportation and communication networks as well as in logistic systems. Hub networks have an influence on flows on the hub-to-hub links and ensure benefit from economies of scale in inter-hub transportation. The key factors for designing a successful hub-and-spoke network are to determine the optimal number of hubs, to properly locate hubs, and to allocate the non-hubs to the hubs. This paper presents the model to determine the l...

Tower-Based Greenhouse Gas Measurement Network Design---The National Institute of Standards and Technology North East Corridor Testbed.

Science.gov (United States)

Lopez-Coto, Israel; Ghosh, Subhomoy; Prasad, Kuldeep; Whetstone, James

2017-09-01

The North-East Corridor (NEC) Testbed project is the 3rd of three NIST (National Institute of Standards and Technology) greenhouse gas emissions testbeds designed to advance greenhouse gas measurements capabilities. A design approach for a dense observing network combined with atmospheric inversion methodologies is described. The Advanced Research Weather Research and Forecasting Model with the Stochastic Time-Inverted Lagrangian Transport model were used to derive the sensitivity of hypothetical observations to surface greenhouse gas emissions (footprints). Unlike other network design algorithms, an iterative selection algorithm, based on a k -means clustering method, was applied to minimize the similarities between the temporal response of each site and maximize sensitivity to the urban emissions contribution. Once a network was selected, a synthetic inversion Bayesian Kalman filter was used to evaluate observing system performance. We present the performances of various measurement network configurations consisting of differing numbers of towers and tower locations. Results show that an overly spatially compact network has decreased spatial coverage, as the spatial information added per site is then suboptimal as to cover the largest possible area, whilst networks dispersed too broadly lose capabilities of constraining flux uncertainties. In addition, we explore the possibility of using a very high density network of lower cost and performance sensors characterized by larger uncertainties and temporal drift. Analysis convergence is faster with a large number of observing locations, reducing the response time of the filter. Larger uncertainties in the observations implies lower values of uncertainty reduction. On the other hand, the drift is a bias in nature, which is added to the observations and, therefore, biasing the retrieved fluxes.

Conceptual design of multi-source CCS pipeline transportation network for Polish energy sector

Science.gov (United States)

Isoli, Niccolo; Chaczykowski, Maciej

2017-11-01

The aim of this study was to identify an optimal CCS transport infrastructure for Polish energy sector in regards of selected European Commission Energy Roadmap 2050 scenario. The work covers identification of the offshore storage site location, CO2 pipeline network design and sizing for deployment at a national scale along with CAPEX analysis. It was conducted for the worst-case scenario, wherein the power plants operate under full-load conditions. The input data for the evaluation of CO2 flow rates (flue gas composition) were taken from the selected cogeneration plant with the maximum electric capacity of 620 MW and the results were extrapolated from these data given the power outputs of the remaining units. A graph search algorithm was employed to estimate pipeline infrastructure costs to transport 95 MT of CO2 annually, which amount to about 612.6 M€. Additional pipeline infrastructure costs will have to be incurred after 9 years of operation of the system due to limited storage site capacity. The results show that CAPEX estimates for CO2 pipeline infrastructure cannot be relied on natural gas infrastructure data, since both systems exhibit differences in pipe wall thickness that affects material cost.

Wind turbines application for energy savings in Gas transportation system

OpenAIRE

Mingaleeva, Renata

2014-01-01

The Thesis shows the perspectives of involving renewable energy resources into the energy balance of Russia, namely the use of wind energy for the purpose of energy supply for the objects of the Russian Gas transportation system. The methodology of the wind energy technical potential calculation is designed and the wind energy technical potential assessment for onshore and offshore zones of Russia is presented. The analysis of Russian Gas transportation system in terms of energy consumption i...

Leveling the playing field of transportation fuels: Accounting for indirect emissions of natural gas

International Nuclear Information System (INIS)

Sexton, Steven; Eyer, Jonathan

2016-01-01

Natural gas transportation fuels are credited in prior studies with greenhouse gas emissions savings relative to petroleum-based fuels and relative to the total emissions of biofuels. These analyses, however, overlook a source of potentially large indirect emissions from natural gas transportation fuels, namely the emissions from incremental coal-fired generation caused by price-induced substitutions away from natural-gas-fired electricity generation. Because coal-fired generation emits substantially more greenhouse gases and criteria air pollutants than natural-gas-fired generation, this indirect coal-use change effect diminishes potential emissions savings from natural gas transportation fuels. Estimates from a parameterized multi-market model suggest the indirect coal-use change effect rivals in magnitude the indirect land-use change effect of biofuels and renders natural gas fuels as carbon intensive as petroleum fuels. - Highlights: •Natural gas used in transport causes indirect emissions in the electricity sector. •These emissions result from increased coal use in electricity generation. •They rival in magnitude indirect land use change (ILUC) emissions of biofuels. •Natural gas fuels are estimated to be as carbon intensive as the petroleum fuels. •Policy ignores indirect emissions from natural gas.

Development of Shale Gas Supply Chain Network under Market Uncertainties

Directory of Open Access Journals (Sweden)

Jorge Chebeir

2017-02-01

Full Text Available The increasing demand of energy has turned the shale gas and shale oil into one of the most promising sources of energy in the United States. In this article, a model is proposed to address the long-term planning problem of the shale gas supply chain under uncertain conditions. A two-stage stochastic programming model is proposed to describe and optimize the shale gas supply chain network. Inherent uncertainty in final products’ prices, such as natural gas and natural gas liquids (NGL, is treated through the utilization of a scenario-based method. A binomial option pricing model is utilized to approximate the stochastic process through the generation of scenario trees. The aim of the proposed model is to generate an appropriate and realistic supply chain network configuration as well as scheduling of different operations throughout the planning horizon of a shale gas development project.

Road Transport Network Analysis In Port-Harcourt Metropolics ...

African Journals Online (AJOL)

Road transport network contributes to the economy of an area as it connects points of origin to destinations. The thrust of this article therefore, is on the analysis of the road networks in Port – Harcourt metropolis with the aim of determining the connectivity of the road networks and the most accessible node. Consequently ...

Pt-modified carbon nanotube networked layers for enhanced gas microsensors

International Nuclear Information System (INIS)

Penza, M.; Rossi, R.; Alvisi, M.; Suriano, D.; Serra, E.

2011-01-01

Carbon nanotubes (CNTs) networked films have been grown by chemical vapor deposition (CVD) technology onto miniaturized low-cost alumina substrates, coated by nanosized Co-catalyst for growing CNTs, to perform chemical detection of toxic gasses (NO 2 and NH 3 ), greenhouse gasses (CO 2 and CH 4 ) and domestic safety gasses (CO and C 2 H 5 OH) at an operating sensor temperature of 120 °C. The morphology and structure of the CNTs networks have been characterized by scanning electron microscopy (SEM). A dense network of bundles of multiple tubes consisting of multi-walled carbon nanostructures appears with a maximum length of 1–5 μm and single-tube diameter varying in the range of 5–40 nm. Surface modifications of the CNTs networks with sputtered Platinum (Pt) nanoclusters, at tuned loading of 8, 15 and 30 nm, provide higher sensitivity for significantly enhanced gas detection compared to un-decorated CNTs. This could be caused by a spillover of the targeted gas molecules onto Pt-catalyst surface with a chemical gating into CNTs layers. The measured electrical conductance of the functionalized CNTs upon exposures of a given oxidizing and reducing gas is modulated by a charge transfer model with p-type semiconducting characteristics. The effect of activated carbons as chemical filters to reduce the influence of the domestic interfering alcohols on CO gas detection has been studied. Functionalized CNT gas sensors exhibited better performances compared to unmodified CNTs, making them highly promising candidates for functional applications of gas control and alarms.

Blending Hydrogen into Natural Gas Pipeline Networks. A Review of Key Issues

Energy Technology Data Exchange (ETDEWEB)

Melaina, M. W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Antonia, O. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Penev, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2013-03-01

This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines. Blending hydrogen into the existing natural gas pipeline network has also been proposed as a means of increasing the output of renewable energy systems such as large wind farms.

Optimal traffic control in highway transportation networks using linear programming

KAUST Repository

Li, Yanning

2014-06-01

This article presents a framework for the optimal control of boundary flows on transportation networks. The state of the system is modeled by a first order scalar conservation law (Lighthill-Whitham-Richards PDE). Based on an equivalent formulation of the Hamilton-Jacobi PDE, the problem of controlling the state of the system on a network link in a finite horizon can be posed as a Linear Program. Assuming all intersections in the network are controllable, we show that the optimization approach can be extended to an arbitrary transportation network, preserving linear constraints. Unlike previously investigated transportation network control schemes, this framework leverages the intrinsic properties of the Halmilton-Jacobi equation, and does not require any discretization or boolean variables on the link. Hence this framework is very computational efficient and provides the globally optimal solution. The feasibility of this framework is illustrated by an on-ramp metering control example.

Use of artificial neural networks for transport energy demand modeling

International Nuclear Information System (INIS)

Murat, Yetis Sazi; Ceylan, Halim

2006-01-01

The paper illustrates an artificial neural network (ANN) approach based on supervised neural networks for the transport energy demand forecasting using socio-economic and transport related indicators. The ANN transport energy demand model is developed. The actual forecast is obtained using a feed forward neural network, trained with back propagation algorithm. In order to investigate the influence of socio-economic indicators on the transport energy demand, the ANN is analyzed based on gross national product (GNP), population and the total annual average veh-km along with historical energy data available from 1970 to 2001. Comparing model predictions with energy data in testing period performs the model validation. The projections are made with two scenarios. It is obtained that the ANN reflects the fluctuation in historical data for both dependent and independent variables. The results obtained bear out the suitability of the adopted methodology for the transport energy-forecasting problem

Model-based dynamic control and optimization of gas networks

Energy Technology Data Exchange (ETDEWEB)

Hofsten, Kai

2001-07-01

This work contributes to the research on control, optimization and simulation of gas transmission systems to support the dispatch personnel at gas control centres for the decision makings in the daily operation of the natural gas transportation systems. Different control and optimization strategies have been studied. The focus is on the operation of long distance natural gas transportation systems. Stationary optimization in conjunction with linear model predictive control using state space models is proposed for supply security, the control of quality parameters and minimization of transportation costs for networks offering transportation services. The result from the stationary optimization together with a reformulation of a simplified fluid flow model formulates a linear dynamic optimization model. This model is used in a finite time control and state constrained linear model predictive controller. The deviation from the control and the state reference determined from the stationary optimization is penalized quadratically. Because of the time varying status of infrastructure, the control space is also generally time varying. When the average load is expected to change considerably, a new stationary optimization is performed, giving a new state and control reference together with a new dynamic model that is used for both optimization and state estimation. Another proposed control strategy is a control and output constrained nonlinear model predictive controller for the operation of gas transmission systems. Here, the objective is also the security of the supply, quality control and minimization of transportation costs. An output vector is defined, which together with a control vector are both penalized quadratically from their respective references in the objective function. The nonlinear model predictive controller can be combined with a stationary optimization. At each sampling instant, a non convex nonlinear programming problem is solved giving a local minimum

Gas Detection Instrument Based on Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

ANSONG FENG

2013-06-01

Full Text Available The wireless sensor network is used to simulate poisonous gas generating system in the Fire-Fighting Simulated Training System. In the paper, we use the wireless signal to simulate the poisonous gas source and use received signal strength indicator (RSSI to simulate the distance between the fireman and the gas source. The gas detection instrument samples the temperature and sphygmus of the trainee and uses the wireless signal as poisonous gas signal. When the trainee enters into the poisonous gas area, the gas detection instrument warns with sound and light and sends the type, density value, the location of the poisonous gas and vital signs of the trainee to host. The paper discusses the software and hardware design of the gas detection instrument. The system has been used to the several of Fire-Fighting training systems.

Connection Management and Recovery Strategies under Epidemic Network Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2014-01-01

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under attacks. This work proposes four policies for failure handling in a connection-oriented optical transport network, under Generalized MultiProtocol Label Switching control plane, and evaluates their performance under multiple correlated large-scale failures. We employ the Susceptible...... of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections requiring recovery, which translates in improved quality of service to customers....

Towards the development of European networks

International Nuclear Information System (INIS)

Hanreich, G.

2004-01-01

The second AFG (French Gas Association) forum, held on June 17, addressed the issue of links between European networks with presentations by Guenther Hainreich, Director of Trans-European Networks for the European Commission Energy and Transport DG, and Loannis Galanis, Assistant Unit Director for the European Commission Energy and Transport DG. The choice for this topic has been influenced by the opening of gas markets in Europe which supposes that two conditions are fulfilled: first, the existence of gas availabilities, and second, the development of transportation, storage and LNG terminal infrastructures. In this context, the national policies are today the regional variations of a European policy at the service of the reinforcement of isolated areas and of the sustain of expanding areas. It is thus necessary to consider the European point-of-view about the existing infrastructures, their development and their financing means

An artificial neural network strategy for monitoring of gas/oil systems in slug flow pattern; Aplicacao de redes neurais artificiais no monitoramento do escoamento de sistemas gas/oleo em regime de golfadas

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Fernando H.B. [Universidade Tiradentes (UNIT), Aracaju, SE (Brazil). Instituto de Tecnologia e Pesquisa; Universidade Federal de Campina Grande (UFCG), PB (Brazil); Silva, Rosivania P.; Fortuny, Montserrat; Santos, Alexandre F. [Universidade Tiradentes (UNIT), Aracaju, (Brazil). Instituto de Tecnologia e Pesquisa; Nunes, Giovani C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

In the petroleum industry, the design of multiphase production systems requires an accurate estimation of the gas-oil ratio (GOR) in the transporting pipelines. However, existing GOR estimation methods are often inadequate in terms of desired accuracy and application range, due to the complex phase distributions and the wide range of fluid properties encountered in production operations. In this paper, the effectiveness of using artificial neural networks in determining GOR values is evaluated, proving to be a reasonable way to monitor this property during oil transportation. (author)

Robustness and Optimization of Complex Networks : Reconstructability, Algorithms and Modeling

NARCIS (Netherlands)

Liu, D.

2013-01-01

The infrastructure networks, including the Internet, telecommunication networks, electrical power grids, transportation networks (road, railway, waterway, and airway networks), gas networks and water networks, are becoming more and more complex. The complex infrastructure networks are crucial to our

Optimal Operation of Interdependent Power Systems and Electrified Transportation Networks

Directory of Open Access Journals (Sweden)

M. Hadi Amini

2018-01-01

Full Text Available Electrified transportation and power systems are mutually coupled networks. In this paper, a novel framework is developed for interdependent power and transportation networks. Our approach constitutes solving an iterative least cost vehicle routing process, which utilizes the communication of electrified vehicles (EVs with competing charging stations, to exchange data such as electricity price, energy demand, and time of arrival. The EV routing problem is solved to minimize the total cost of travel using the Dijkstra algorithm with the input from EVs battery management system, electricity price from charging stations, powertrain component efficiencies and transportation network traffic conditions. Through the bidirectional communication of EVs with competing charging stations, EVs’ charging demand estimation is done much more accurately. Then the optimal power flow problem is solved for the power system, to find the locational marginal price at load buses where charging stations are connected. Finally, the electricity prices were communicated from the charging stations to the EVs, and the loop is closed. Locational electricity price acts as the shared parameter between the two optimization problems, i.e., optimal power flow and optimal routing problem. Electricity price depends on the power demand, which is affected by the charging of EVs. On the other hand, location of EV charging stations and their different pricing strategies might affect the routing decisions of the EVs. Our novel approach that combines the electrified transportation with power system operation, holds tremendous potential for solving electrified transportation issues and reducing energy costs. The effectiveness of the proposed approach is demonstrated using Shanghai transportation network and IEEE 9-bus test system. The results verify the cost-savings for both power system and transportation networks.

Alternative transport network designs and their implications for intermodal transhipment technologies

OpenAIRE

Woxenius, Johan

2007-01-01

Six principles for operation of the rail part of intermodal rail freight transport systems are described: direct link, corridor, hub-and-spoke, connected hubs, static routes, and dynamic routes. The first part is a theoretical discussion of the characteristics of the transport network designs. The theory is then applied to intermodal freight transport by analysing how each transport network design affects the need for terminal performance. The discussion includes a classification of existing ...

Connectivity, flow and transport in network models of fractured media

International Nuclear Information System (INIS)

Robinson, P.C.

1984-10-01

In order to evaluate the safety of radioactive waste disposal underground it is important to understand the way in which radioactive material is transported through the rock to the surface. If the rock is fractured the usual models may not be applicable. In this work we look at three aspects of fracture networks: connectivity, flow and transport. These are studied numerically by generating fracture networks in a computer and modelling the processes which occur. Connectivity relates to percolation theory, and critical densities for fracture systems are found in two and three dimensions. The permeability of two-dimensional networks is studied. The way that permeability depends on fracture density, network size and spread of fracture length can be predicted using a cut lattice model. Transport through the fracture network by convection through the fractures and mixing at the intersections is studied. The Fickian dispersion equation does not describe the resulting hydrodynamic dispersion. Extensions to the techniques to three dimensions and to include other processes are discussed. (author)

An improved model of fission gas atom transport in irradiated uranium dioxide

Science.gov (United States)

Shea, J. H.

2018-04-01

The hitherto standard approach to predicting fission gas release has been a pure diffusion gas atom transport model based upon Fick's law. An additional mechanism has subsequently been identified from experimental data at high burnup and has been summarised in an empirical model that is considered to embody a so-called fuel matrix 'saturation' phenomenon whereby the fuel matrix has become saturated with fission gas so that the continued addition of extra fission gas atoms results in their expulsion from the fuel matrix into the fuel rod plenum. The present paper proposes a different approach by constructing an enhanced fission gas transport law consisting of two components: 1) Fick's law and 2) a so-called drift term. The new transport law can be shown to be effectively identical in its predictions to the 'saturation' approach and is more readily physically justifiable. The method introduces a generalisation of the standard diffusion equation which is dubbed the Drift Diffusion Equation. According to the magnitude of a dimensionless Péclet number, P, the new equation can vary from pure diffusion to pure drift, which latter represents a collective motion of the fission gas atoms through the fuel matrix at a translational velocity. Comparison is made between the saturation and enhanced transport approaches. Because of its dependence on P, the Drift Diffusion Equation is shown to be more effective at managing the transition from one type of limiting transport phenomenon to the other. Thus it can adapt appropriately according to the reactor operation.

Underground Coal Gasification: Rates of Post Processing Gas Transport

Czech Academy of Sciences Publication Activity Database

Soukup, Karel; Hejtmánek, Vladimír; Stanczyk, K.; Šolcová, Olga

2014-01-01

Roč. 68, č. 12 (2014), s. 1707-1715 ISSN 0366-6352 R&D Projects: GA MŠk 7C12017 Grant - others:RFCS(XE) RFCR-CT-2011-00002 Institutional support: RVO:67985858 Keywords : underground coal gas ification * gas transport * textural properties Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.468, year: 2014

The open access and the natural gas ducts: transport and distribution; O livre acesso e os dutos de gas natural: transporte e distribuicao

Energy Technology Data Exchange (ETDEWEB)

Siqueira, Mariana de; Xavier, Yanko Marcius de Alencar [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2008-07-01

The present research, attempting for the economic relevance of the natural gas sector, for the lack of a law that disciplines it and, still, for the structural question of the natural gas ducts activities; it analyzes, in a comparative way, the monopoly of the natural gas ducts activities and the mechanisms of competition chosen to brighten up it: the open access and the by pas. The transport and the distribution of the natural gas are really similar, but the ways to insert the competition in its areas are not. (author)

RAETRAD MODEL OF RADON GAS GENERATION, TRANSPORT, AND INDOOR ENTRY

Science.gov (United States)

The report describes the theoretical basis, implementation, and validation of the Radon Emanation and Transport into Dwellings (RAETRAD) model, a conceptual and mathematical approach for simulating radon (222Rn) gas generation and transport from soils and building foundations to ...

Flow-pattern identification and nonlinear dynamics of gas-liquid two-phase flow in complex networks.

Science.gov (United States)

Gao, Zhongke; Jin, Ningde

2009-06-01

The identification of flow pattern is a basic and important issue in multiphase systems. Because of the complexity of phase interaction in gas-liquid two-phase flow, it is difficult to discern its flow pattern objectively. In this paper, we make a systematic study on the vertical upward gas-liquid two-phase flow using complex network. Three unique network construction methods are proposed to build three types of networks, i.e., flow pattern complex network (FPCN), fluid dynamic complex network (FDCN), and fluid structure complex network (FSCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K -mean clustering, useful and interesting results are found which can be used for identifying five vertical upward gas-liquid two-phase flow patterns. To investigate the dynamic characteristics of gas-liquid two-phase flow, we construct 50 FDCNs under different flow conditions, and find that the power-law exponent and the network information entropy, which are sensitive to the flow pattern transition, can both characterize the nonlinear dynamics of gas-liquid two-phase flow. Furthermore, we construct FSCN and demonstrate how network statistic can be used to reveal the fluid structure of gas-liquid two-phase flow. In this paper, from a different perspective, we not only introduce complex network theory to the study of gas-liquid two-phase flow but also indicate that complex network may be a powerful tool for exploring nonlinear time series in practice.

CRE proposal for the tariffs of use of natural gas distribution networks

International Nuclear Information System (INIS)

Syrota, J.

2003-12-01

Each French manager of a natural gas distribution network has its own tariff of network use. This document defines the general tariffing rules applicable to all natural gas distribution networks (options, penalties in case of overstepping of the subscribed daily capacity, special option for the supply of the 'Gaz de Barr' network, services included in the tariff). The detailed tariffs of use are given for each gas utility (Gaz de France, Gaz de Bordeaux, Gaz de Strasbourg, Regie Municipale de Colmar (Vialis), Gaz Electricite de Grenoble, Regie Municipale de Dreux (GEdia), Gaz de Barr, Service Gaz et Eau de la Ville de Guebwiller, Syndicat Intercommunal de Huningue, St Louis, Hegenheim et Village Neuf, Regie d'Equipement et Gaz de la Vienne etc..). (J.S.)

CNG transport by ship with FRP pressure vessels access to east coast gas

Energy Technology Data Exchange (ETDEWEB)

Campbell, S. [Trans Ocean Gas Inc., St. John' s, NL (Canada)

2005-07-01

This paper discussed the Trans Ocean Gas (TOG) method for transporting compressed natural gas (CNG). CNG transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets that are not feasible for liquefied natural gas (LNG) or pipelines. Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. FRP pressure vessels have been proven safe and reliable through critical applications in the national defense, aerospace, and natural gas vehicle industries. They are light-weight, highly reliable, have very safe failure modes, are corrosion resistant, and have excellent low temperature characteristics. Under TOG's scheme, natural gas can be stored at two thirds the density of LNG without costly processing. TOG's proposed design and testing of a CNG system was reviewed in detail. figs.

A liquefied energy chain for transport and utilization of natural gas for power production with CO2 capture and storage - Part 4: Sensitivity analysis of transport pressures and benchmarking with conventional technology for gas transport

International Nuclear Information System (INIS)

Aspelund, Audun; Gundersen, Truls

2009-01-01

A novel energy and cost effective transport chain for stranded natural gas utilized for power production with CO 2 capture and storage is developed. It includes an offshore section, a combined gas carrier and an integrated receiving terminal. In the offshore section, natural gas (NG) is liquefied to LNG by liquid carbon dioxide (LCO 2 ) and liquid inert nitrogen (LIN), which are used as cold carriers. In the onshore process, the cryogenic exergy in the LNG is utilized to cool and liquefy the cold carriers, LCO 2 and LIN. The transport pressures for LNG, LIN and LCO 2 will influence the thermodynamic efficiency as well as the ship utilization; hence sensitivity analyses are performed, showing that the ship utilization for the payload will vary between 58% and 80%, and the transport chain exergy efficiency between 48% and 52%. A thermodynamically optimized process requires 319 kWh/tonne LNG. The NG lost due to power generation needed to operate the LEC processes is roughly one third of the requirement in a conventional transport chain for stranded NG gas with CO 2 capture and sequestration (CCS)

Feasibility study for bottled gas and LPG in Poland

International Nuclear Information System (INIS)

1992-04-01

With a total population of ca. 40 million, Poland has an annual consumption of liquefied petroleum gas amounting to 180,000 tons, used by 2.5 million bottled-gas consumers. The consumer pattern is expected to change, with an increasing market for gas for industrial purposes and for heating. Distribution systems will also change to include tank installations in many sizes and transport with large tank lorries. LPG is estimated to be competitive with other forms of energy, and the market is expected to increase to up to ca. 500,000 tons per year. Restricting factors are shortage of supply and lack of approved applications, transport equipment and tank facilities. A list of existing bottle gas companies and evaluation of the technical facilities in the Polish Oil and Gas Company in Gydnia are included. Bottled gas is currently distributed under normal conditions and, market prices for LPG have remained stable in Poland. Detailed studies of the current distribution network in the Suwalki area are given. It should be possible to extend the existing distribution network. A proposal for the establishment of standard tank installations and the gas supply for the town of Augustow is presented. Considerable investments will have to be made in terminals, tank plants and transport equipment, and international oil companies are expected to play an important role in this market. The European Bank for Restructuring and Development could possibly contribute to the financing of the pipe network. (AB)

Underwater sound and vibrations due to oil & gas activities

NARCIS (Netherlands)

Beek, P.J.G. van; Binnerts, B.; Nennie, E.D.; Benda-Beckmann, A.M. von

2014-01-01

In the oil & gas industry there is a trend towards more subsea activities. To improve gas recovery from existing and new fields at greater depths, the produced gas will be compressed, processed and transported via subsea templates and underwater networks (pipelines, flexible risers, etc.). Besides

Flexible Transport Network Expansion via Open WDM Interfaces

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Skjoldstrup, Bjarke

2013-01-01

This paper presents a successful test-bed implementation of a multi-vendor transport network interconnection via open WDM interfaces. The concept of applying Alien Wavelengths (AWs) for network expansion was successfully illustrated via deployment of multi-domain/multi-vendor end-to-end OTN servi...

A Single-Walled Carbon Nanotube Network Gas Sensing Device

Directory of Open Access Journals (Sweden)

I-Ju Teng

2011-08-01

Full Text Available The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD. The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3.

Feedforward Nonlinear Control Using Neural Gas Network

OpenAIRE

Machón-González, Iván; López-García, Hilario

2017-01-01

Nonlinear systems control is a main issue in control theory. Many developed applications suffer from a mathematical foundation not as general as the theory of linear systems. This paper proposes a control strategy of nonlinear systems with unknown dynamics by means of a set of local linear models obtained by a supervised neural gas network. The proposed approach takes advantage of the neural gas feature by which the algorithm yields a very robust clustering procedure. The direct model of the ...

Risk Analysis on Leakage Failure of Natural Gas Pipelines by Fuzzy Bayesian Network with a Bow-Tie Model

Directory of Open Access Journals (Sweden)

Xian Shan

2017-01-01

Full Text Available Pipeline is the major mode of natural gas transportation. Leakage of natural gas pipelines may cause explosions and fires, resulting in casualties, environmental damage, and material loss. Efficient risk analysis is of great significance for preventing and mitigating such potential accidents. The objective of this study is to present a practical risk assessment method based on Bow-tie model and Bayesian network for risk analysis of natural gas pipeline leakage. Firstly, identify the potential risk factors and consequences of the failure. Then construct the Bow-tie model, use the quantitative analysis of Bayesian network to find the weak links in the system, and make a prediction of the control measures to reduce the rate of the accident. In order to deal with the uncertainty existing in the determination of the probability of basic events, fuzzy logic method is used. Results of a case study show that the most likely causes of natural gas pipeline leakage occurrence are parties ignore signage, implicit signage, overload, and design defect of auxiliaries. Once the leakage occurs, it is most likely to result in fire and explosion. Corresponding measures taken on time will reduce the disaster degree of accidents to the least extent.

Ion transport membrane module and vessel system with directed internal gas flow

Science.gov (United States)

Holmes, Michael Jerome; Ohrn, Theodore R.; Chen, Christopher Ming-Poh

2010-02-09

An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

Intensification of Development of Mixed Transportation of Freight in Ukraine through Formation of the Network of Transportation and Logistic Centres and Transportation and Logistic Clusters

Directory of Open Access Journals (Sweden)

Karpenko Oksana O.

2013-11-01

Full Text Available Development of mixed transportation is a prospective direction of development of the transportation system of Ukraine. The article analyses the modern state of development of mixed transportation of freight in Ukraine. The most popular types of combined transportation (refers to multi-modal are container and contrailer trains, which are formed both in Ukraine (Viking and Yaroslav and in other countries, first of all, Belarus (Zubr. One of the reasons of underdevelopment of mixed transportation of freight in Ukraine is absence of a developed network of transportation and logistic centres. The article offers to form a network of transportation and logistic centres in Ukraine as a way of intensification of development of mixed transportations of freight, since they facilitate co-ordination of use of various types of transport and support integrated management of material flows. Transportation and logistic centres should become a start-up complex, around which transportation and logistic clusters would be gradually formed. Transportation and logistic clusters is a new efficient form of network organisation and management of transportation and logistic services and they also ensure growth of efficiency of use of the regional transportation and logistic potential of Ukraine. The article shows prospective supporting transportation and logistic centres and centres of formation of transportation and logistic clusters in the territory of Ukraine. Formation of efficient transportation and logistic system of Ukraine on the basis of a network of transportation and logistic clusters would facilitate entering of Ukraine into the world transportation environment and would allow acceleration of introduction of efficient logistic schemes of freight delivery, in particular, mixed transportation of freight.

Anomalous Transport in Natural Fracture Networks Induced by Tectonic Stress

Science.gov (United States)

Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

2017-12-01

Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the high uncertainty and large heterogeneity associated with fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transportthrough fractured rock remains poorly understood. The link between anomalous (non-Fickian) transport and confining stress has been shown, only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of geologic (tectonic) stress on flow and tracer transport through natural fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM) [2], which can capture the deformation of matrix blocks, reactivation of pre-existing fractures, and propagation of new cracks, upon changes in the stress field. We apply the model to a fracture network extracted from the geological map of an actual rock outcrop to obtain the aperture field at different stress conditions. We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture network, and show that the stress state is a powerful determinant of transport behavior: (1) An anisotropic stress state induces preferential flow paths through shear dilation; (2) An increase in geologic stress increases aperture heterogeneity that induces late-time tailing of particle breakthrough curves. Finally, we develop an effective transport model that captures the anomalous transport through the stressed fracture

Optimal hub location in pipeline networks

Energy Technology Data Exchange (ETDEWEB)

Dott, D.R.; Wirasinghe, S.C.; Chakma, A. [Univ. of Calgary, Alberta (Canada)

1996-12-31

This paper discusses optimization strategies and techniques for the location of natural gas marketing hubs in the North American gas pipeline network. A hub is a facility at which inbound and outbound network links meet and freight is redirected towards their destinations. Common examples of hubs used in the gas pipeline industry include gas plants, interconnects and market centers. Characteristics of the gas pipeline industry which are relevant to the optimization of transportation costs using hubs are presented. Allocation techniques for solving location-allocation problems are discussed. An outline of the research in process by the authors in the field of optimal gas hub location concludes the paper.

Risk analysis of urban gas pipeline network based on improved bow-tie model

Science.gov (United States)

Hao, M. J.; You, Q. J.; Yue, Z.

2017-11-01

Gas pipeline network is a major hazard source in urban areas. In the event of an accident, there could be grave consequences. In order to understand more clearly the causes and consequences of gas pipeline network accidents, and to develop prevention and mitigation measures, the author puts forward the application of improved bow-tie model to analyze risks of urban gas pipeline network. The improved bow-tie model analyzes accident causes from four aspects: human, materials, environment and management; it also analyzes the consequences from four aspects: casualty, property loss, environment and society. Then it quantifies the causes and consequences. Risk identification, risk analysis, risk assessment, risk control, and risk management will be clearly shown in the model figures. Then it can suggest prevention and mitigation measures accordingly to help reduce accident rate of gas pipeline network. The results show that the whole process of an accident can be visually investigated using the bow-tie model. It can also provide reasons for and predict consequences of an unfortunate event. It is of great significance in order to analyze leakage failure of gas pipeline network.

Traffic Management for Next Generation Transport Networks

DEFF Research Database (Denmark)

Yu, Hao

required by the next generation transport network to provide Quality-of-Service (QoS) guaranteed video services. Augmenting network capacity and upgrading network nodes indicate long deployment period, replacement of equipment and thus significant cost to the network service providers. This challenge may...... slacken the steps of some network operators towards providing IPTV services. In this dissertation, the topology-based hierarchical scheduling scheme is proposed to tackle the problem addressed. The scheme simplifies the deployment process by placing an intelligent switch with centralized traffic...... management functions at the edge of the network, scheduling traffic on behalf of the other nodes. The topology-based hierarchical scheduling scheme is able to provide outstanding flow isolation due to its centralized scheduling ability, which is essential for providing IPTV services. In order to reduce...

Estimation of Energy Consumption and Greenhouse Gas Emissions of Transportation in Beef Cattle Production

Directory of Open Access Journals (Sweden)

Narayanan Kannan

2016-11-01

Full Text Available Accounting for transportation is an important part of the life cycle analysis (LCA of beef cattle production because it is associated with energy consumption and greenhouse gas emissions. This paper describes the development and application of a model that estimates energy consumption and greenhouse gas emissions of transport in beef cattle production. The animal transport model is based on the weight and number of animals in each weight category, type of trailer, vehicle, and fuel used. The energy consumption and greenhouse gas emission estimates of animal feed transportation are based on the weight of a truckload and the number of truckloads of feed transported. Our results indicate that a truckload is travelling approximately 326 km in connection with beef cattle production in the study region. The fuel consumption amounts to 24 L of fossil fuel per 1000 kg of boneless beef. The corresponding greenhouse gas emission is 83 kg. It appears from our results that the majority of energy consumption and greenhouse gas emissions are associated with sending the finished cattle to slaughterhouses and bringing feeder cattle to feedlots. Our results point out appreciable reductions in energy consumption and greenhouse gas emissions by changing from conventional fuel to bio-fuel.

2009 South American benchmarking study: natural gas transportation companies

Energy Technology Data Exchange (ETDEWEB)

Jordan, Nathalie [Gas TransBoliviano S.A. (Bolivia); Walter, Juliana S. [TRANSPETRO, Rio de Janeiro, RJ (Brazil)

2009-07-01

In the current business environment large corporations are constantly seeking to adapt their strategies. Benchmarking is an important tool for continuous improvement and decision-making. Benchmarking is a methodology that determines which aspects are the most important to be improved upon, and it proposes establishing a competitive parameter in an analysis of the best practices and processes, applying continuous improvement driven by the best organizations in their class. At the beginning of 2008, GTB (Gas TransBoliviano S.A.) contacted several South American gas transportation companies to carry out a regional benchmarking study in 2009. In this study, the key performance indicators of the South American companies, whose reality is similar, for example, in terms of prices, availability of labor, and community relations, will be compared. Within this context, a comparative study of the results, the comparative evaluation among natural gas transportation companies, is becoming an essential management instrument to help with decision-making. (author)

Bulk Restoration for SDN-Based Transport Network

Directory of Open Access Journals (Sweden)

Yang Zhao

2016-01-01

Full Text Available We propose a bulk restoration scheme for software defined networking- (SDN- based transport network. To enhance the network survivability and improve the throughput, we allow disrupted flows to be recovered synchronously in dynamic order. In addition backup paths are scheduled globally by applying the principles of load balance. We model the bulk restoration problem using a mixed integer linear programming (MILP formulation. Then, a heuristic algorithm is devised. The proposed algorithm is verified by simulation and the results are analyzed comparing with sequential restoration schemes.

Transport and reaction processes affecting the attenuation of landfill gas in cover soils

DEFF Research Database (Denmark)

Molins, S.; Mayer, K.U.; Scheutz, Charlotte

2008-01-01

of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate, the contributions of various gas transport processes on methane attenuation in landfill cover soils....... For this purpose, a reactive transport model that includes advection and the Dusty Gas Model for simulation of multicomponent gas diffusion was used. The simulations are constrained by data from a series of counter-gradient laboratory experiments. Diffusion typically accounts for over 99% of methane emission...... to the atmosphere. Oxygen supply into the soil column is driven exclusively by diffusion, whereas advection outward offsets part of the diffusive contribution. In the reaction zone, methane consumption reduces the pressure gradient, further decreasing the significance of advection near the top of the column...

Advances in dynamic network modeling in complex transportation systems

CERN Document Server

Ukkusuri, Satish V

2013-01-01

This book focuses on the latest in dynamic network modeling, including route guidance and traffic control in transportation systems and other complex infrastructure networks. Covers dynamic traffic assignment, flow modeling, mobile sensor deployment and more.

Fast long-range connections in transportation networks

International Nuclear Information System (INIS)

Palhares Viana, Matheus; Fontoura Costa, Luciano da

2011-01-01

Multidimensional scaling is applied in order to visualize an analogue of the small-world effect implied by edges having different displacement velocities in transportation networks. Our findings are illustrated for two real-world systems, namely the London urban network (streets and underground) and the US highway network enhanced by some of the main US airlines routes. We also show that the travel time in these two networks is drastically changed by attacks targeting the edges with large displacement velocities. - Highlights: → Multidimensional scaling used to visualize the effects of fast long-range connections. → Fast long-range connections are important to decrease the average travel time. → The average travel time diverges quickly when the network is under target attacks.

Characterization of Nanoscale Gas Transport in Shale Formations

Science.gov (United States)

Chai, D.; Li, X.

2017-12-01

Non-Darcy flow behavior can be commonly observed in nano-sized pores of matrix. Most existing gas flow models characterize non-Darcy flow by empirical or semi-empirical methods without considering the real gas effect. In this paper, a novel layered model with physical meanings is proposed for both ideal and real gas transports in nanopores. It can be further coupled with hydraulic fracturing models and consequently benefit the storage evaluation and production prediction for shale gas recovery. It is hypothesized that a nanotube can be divided into a central circular zone where the viscous flow behavior mainly exists due to dominant intermolecular collisions and an outer annular zone where the Knudsen diffusion mainly exists because of dominant collisions between molecules and the wall. The flux is derived based on integration of two zones by applying the virtual boundary. Subsequently, the model is modified by incorporating slip effect, real gas effect, porosity distribution, and tortuosity. Meanwhile, a multi-objective optimization method (MOP) is applied to assist the validation of analytical model to search fitting parameters which are highly localized and contain significant uncertainties. The apparent permeability is finally derived and analyzed with various impact factors. The developed nanoscale gas transport model is well validated by the flux data collected from both laboratory experiments and molecular simulations over the entire spectrum of flow regimes. It has a decrease of as much as 43.8% in total molar flux when the real gas effect is considered in the model. Such an effect is found to be more significant as pore size shrinks. Knudsen diffusion accounts for more than 60% of the total gas flux when pressure is lower than 0.2 MPa and pore size is smaller than 50 nm. Overall, the apparent permeability is found to decrease with pressure, though it rarely changes when pressure is higher than 5.0 MPa and pore size is larger than 50 nm.

Gas-phase transport of fission products

International Nuclear Information System (INIS)

Tang, I.N.; Munkelwitz, H.R.

1982-01-01

The paper presents the results of an experimental investigation to show the importance of nuclear aerosol formation as a mechanism for semi-volatile fission product transport under certain postulated HTGR accident conditions. Simulated fission product Sr and Ba as oxides are impregnated in H451 graphite and released at elevated temperatures into a dry helium flow. In the presence of graphite, the oxides are quantitatively reduced to metals, which subsequently vaporize at temperatures much lower than required for the oxides alone to vaporize in the absence of graphite. A substantial fraction of the released material is associated with particulate matter, which is collected on filters located downstream at ambient temperatures. Increasing carrier-gas flow rate greatly enhances the extent of particulate transport. The release and transport of simulated fission product Ag as metal are also investigated. Electron microscopic examinations of the collected Sr and Ag aerosols show large agglomerates composed of primary particles roughly 0.06 to 0.08 μm in diameter

Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

Directory of Open Access Journals (Sweden)

Chaohua Guo

Full Text Available Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

Artificial neural networks for monitoring the gas turbine; Artificiella neuronnaet foer gasturbinoevervakning

Energy Technology Data Exchange (ETDEWEB)

Fast, Magnus; Thern, Marcus [Inst. foer Energivetenskaper, Lunds Univ. (Sweden)

2011-10-15

Through available historical operational data from gas turbines, fast, accurate, easy to use and reliable models can be developed. These models can be used for monitoring of gas turbines and assist in the transition from today's time-based maintenance to condition based maintenance. For the end user this means that, because only operational data is needed, they can easily develop their own tools independent of the manufacturer. Traditionally these types of models are constructed with physical relations for e.g., mass, energy and momentum. To develop a model with physical relations is often laborious and requires classified information which the end user does not have access to. Research has shown that by producing models using operational data a very high model precision can be achieved. When implementing these models in a power plant computer system the gas turbine's performance can be monitored in real time. This can facilitate fault detection at an early stage, and if necessary, stop the gas turbine before major damage occurs. For the power plant owner, this means that the gas turbine reliability is increased since the need for maintenance is minimized and the downtime is reduced. It also means that a measure of the gas turbine's overall status is continuously available, with respect to e.g. degradation, which helps in the planning of service intervals. The tool used is called artificial neural networks (ANN), a collective name for a number of algorithms for information processing that attempts to mimic the nerve cell function. Just like real networks of neurons in a brain, these artificial neural networks have the ability to learn. In this case, neural networks are trained to mimic the behavior of gas turbines by introducing them to data from real gas turbines. After a neural network is trained it represents a very accurate model of the gas turbine that it is trained to emulate.

Solving the gas transmission problem with consideration of the compressors

OpenAIRE

Bakhouya, Bouchra; de Wolf, Daniel

2008-01-01

In [7], De Wolf and Smeers consider the problem of the gas distribution through a network of pipelines. The problem was formulated as a cost minimization subject to nonlinear flow-pressure relations, material balances and pressure bounds. This model does not reflect any more the current situation on the gas market. Today, the transportation and gas buying functions are separated. This work considers the new situation for the transportation company. The objective for the tran...

Evaluation of axial fission gas transport in power ramping experiments

International Nuclear Information System (INIS)

Kinoshita, Motoyasu

1986-01-01

The LINUS code calculates advective and diffusional transport of fission gas towards an upper plenum through the pellet-cladding gap. The basic equations were modified for analyzing a multi-component gas mixture in the gap and also for dealing with opening and/or closing of the gap, which induces additional axial gas flow. Analysis of the Petten ramp experiment shows that helium pressurization is effective in suppressing an ascending rate of fission gas concentration. After the maximum concentration is achieved through power ramping, the gas concentration could be described by a steady state analytical solution which does not depend on the filling gas pressure. (author)

Reducing greenhouse gas emissions from u.s. transportation

Science.gov (United States)

2010-01-01

This report examines the prospects for substantially reducing the greenhouse gas (GHG) emissions from the U.S. transportation sector, which accounts for 27 percent of the GHG emissions of the entire U.S. economy and 30 percent of the world's transpor...

Natural gas consumption within GRTgaz@s balancing zones - Year 2009

International Nuclear Information System (INIS)

2010-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents some key figures about GRTgaz activity in 2009: Gross and climate-adjusted consumption on GRTgaz's territory, Quantities of natural gas transported by GRTgaz in 2008 and 2009

Energy transition: gas asserts its assets

International Nuclear Information System (INIS)

Passebon, Philippe; Lesquel, Emmanuelle; Leroux, Hugo

2016-01-01

Even though it is a fossil energy, gas has a role to play in energy transition as it emits less CO 2 than oil or coal. In this context, it can be used to fill the gaps due to intermittency of some renewable energies, and moreover can also be obtained from organic matter, and then becomes also a renewable source. A set of articles addresses and illustrates these different issues: the development of technologies to exploit methane, the role of substitute for gas, the assets of methane, of natural gas and of biogas, the transformation of electricity into gas in order to easily store energy (notably in the network gas according to the power-to-gas principle), the development of biomass-based methane, the replacement of oil by LNG (liquefied natural gas) in industry and transports (road and sea transport notably)

Structural properties of the Chinese air transportation multilayer network

International Nuclear Information System (INIS)

Hong, Chen; Zhang, Jun; Cao, Xian-Bin; Du, Wen-Bo

2016-01-01

Highlights: • We investigate the structural properties of the Chinese air transportation multilayer network (ATMN). • We compare two main types of layers corresponding to major and low-cost airlines. • It is found that small-world property and rich-club effect of the Chinese ATMN are mainly caused by major airlines. - Abstract: Recently multilayer networks are attracting great attention because the properties of many real-world systems cannot be well understood without considering their different layers. In this paper, we investigate the structural properties of the Chinese air transportation multilayer network (ATMN) by progressively merging layers together, where each commercial airline (company) defines a layer. The results show that the high clustering coefficient, short characteristic path length and large collection of reachable destinations of the Chinese ATMN can only emerge when several layers are merged together. Moreover, we compare two main types of layers corresponding to major and low-cost airlines. It is found that the small-world property and the rich-club effect of the Chinese ATMN are mainly caused by those layers corresponding to major airlines. Our work will highlight a better understanding of the Chinese air transportation network.

Pore size distribution effect on rarefied gas transport in porous media

Science.gov (United States)

Hori, Takuma; Yoshimoto, Yuta; Takagi, Shu; Kinefuchi, Ikuya

2017-11-01

Gas transport phenomena in porous media are known to strongly influence the performance of devices such as gas separation membranes and fuel cells. Knudsen diffusion is a dominant flow regime in these devices since they have nanoscale pores. Many experiments have shown that these porous media have complex structures and pore size distributions; thus, the diffusion coefficient in these media cannot be easily assessed. Previous studies have reported that the characteristic pore diameter of porous media can be defined in light of the pore size distribution; however, tortuosity factor, which is necessary for the evaluation of diffusion coefficient, is still unknown without gas transport measurements or simulations. Thus, the relation between pore size distributions and tortuosity factors is required to obtain the gas transport properties. We perform numerical simulations to prove the relation between them. Porous media are numerically constructed while satisfying given pore size distributions. Then, the mean-square displacement simulation is performed to obtain the tortuosity factors of the constructed porous media.. This paper is based on results obtained from a project commissioned by the New Energy and Industrial Development Organization (NEDO).

Long-term financial transportation rights : An experiment

NARCIS (Netherlands)

Henze, B.; Noussair, C.N.; Willems, Bert; Kristainsen, T.; Rosellon, J.

2013-01-01

One challenge facing operators of network infrastructure, such as gas pipelines and electricity grids, is that large new investments in capacity must be undertaken as overall demand increases. In the European Union alone, roughly 200 Billion Euro must be invested in the energy transport networks

Correlating Gas Transport Parameters and X-ray Computed Tomography Measurements in Porous Media

DEFF Research Database (Denmark)

Naveed, Muhammad; Hamamoto, Shoichiro; Kawamoto, Ken

2013-01-01

physical processes. The objective of this study was to characterize the relationships between gas transport parameters and soil-pore geometry revealed by X-ray CT. Sands of different shapes with a mean particle diameter (d50) ranging from 0.19 to 1.51 mm were used as porous media under both air...... was found between α and tortuosity calculated from gas transport parameters (Equation (Uncited) Image Tools), indicating that gas dispersivity has a linear and inverse relationship with gas diffusivity. A linear relationship was also found between ka and d50/TUMS2, indicating a strong dependency of ka...

Development of Novel Gas Brand Anti-Piracy System based on BP Neural Networks

Energy Technology Data Exchange (ETDEWEB)

Wang, L [School of Aeronautics and Astronautics, Tongji University, Shanghai (China); Zhang, Y Y [Chinese-German School of Postgraduate Studies, Tongji University (China); Ding, L [Chinese-German School of Postgraduate Studies, Tongji University (China)

2006-10-15

The Wireless-net Close-loop gas brand anti-piracy system introduced in this paper is a new type of brand piracy technical product based on BP neural network. It is composed by gas brand piracy label possessing gas exhalation resource, ARM embedded gas-detector, GPRS wireless module and data base of merchandise information. First, the system obtains the information on the special label through gas sensor array ,then the attained signals are transferred into ARM Embedded board and identified by artificial neural network, and finally turns back the outcome of data collection and identification to the manufactures with the help of GPRS module.

Development of Novel Gas Brand Anti-Piracy System based on BP Neural Networks

Science.gov (United States)

Wang, L.; Zhang, Y. Y.; Ding, L.

2006-10-01

The Wireless-net Close-loop gas brand anti-piracy system introduced in this paper is a new type of brand piracy technical product based on BP neural network. It is composed by gas brand piracy label possessing gas exhalation resource, ARM embedded gas-detector, GPRS wireless module and data base of merchandise information. First, the system obtains the information on the special label through gas sensor array ,then the attained signals are transferred into ARM Embedded board and identified by artificial neural network, and finally turns back the outcome of data collection and identification to the manufactures with the help of GPRS module.

Development of Novel Gas Brand Anti-Piracy System based on BP Neural Networks

International Nuclear Information System (INIS)

Wang, L; Zhang, Y Y; Ding, L

2006-01-01

The Wireless-net Close-loop gas brand anti-piracy system introduced in this paper is a new type of brand piracy technical product based on BP neural network. It is composed by gas brand piracy label possessing gas exhalation resource, ARM embedded gas-detector, GPRS wireless module and data base of merchandise information. First, the system obtains the information on the special label through gas sensor array ,then the attained signals are transferred into ARM Embedded board and identified by artificial neural network, and finally turns back the outcome of data collection and identification to the manufactures with the help of GPRS module

The accessibility of Poland’s Space to the Trans-European Transport Network

Directory of Open Access Journals (Sweden)

Wiśniewski Szymon

2017-09-01

Full Text Available The aim of the article is to analyse the land transport accessibility of two trans-European corridors within the boundaries of Poland. The adjustment of the course of transport routes to the distribution of the population and the country’s land development (including economic potential and logistic infrastructure was outlined using measurements of cumulative accessibility. The results were presented in both cartographic form (isochrone approach and tabular form (cumulative approach. Research was conducted adopting different forms of transport used for relocation (including foot traffic, car, rail and multimodal transport and both the current and target layout of the transport network. This made it possible to determine the changes that will effectively run the process of investment in transport infrastructure on Polish territory. This allowed the identification of the areas of Poland which are particularly conveniently located in relation to domestic connections (in terms of the international network and those for which the European transport network remains difficult to access.

Numerical simulation for gas-liquid two-phase flow in pipe networks

International Nuclear Information System (INIS)

Li Xiaoyan; Kuang Bo; Zhou Guoliang; Xu Jijun

1998-01-01

The complex pipe network characters can not directly presented in single phase flow, gas-liquid two phase flow pressure drop and void rate change model. Apply fluid network theory and computer numerical simulation technology to phase flow pipe networks carried out simulate and compute. Simulate result shows that flow resistance distribution is non-linear in two phase pipe network

Deployment Algorithms of Wireless Sensor Networks for Near-surface Underground Oil and Gas Pipeline Monitoring

Directory of Open Access Journals (Sweden)

Hua-Ping YU

2014-07-01

Full Text Available Oil and gas pipelines are the infrastructure of national economic development. Deployment problem of wireless underground sensor networks (WUSN for oil and gas pipeline systems is a fundamental problem. This paper firstly analyzed the wireless channel characteristics and energy consumption model in near-surface underground soil, and then studied the spatial structure of oil and gas pipelines and introduced the three-layer system structure of WUSN for oil and gas pipelines monitoring. Secondly, the optimal deployment strategy in XY plane and XZ plane which were projected from three-dimensional oil and gas pipeline structure was analyzed. Thirdly, the technical framework of using kinetic energy of the fluid in pipelines to recharge sensor nodes and partition strategy for energy consumption balance based on the wireless communication technology of magnetic induction waveguide were proposed, which can effectively improve the energy performance and connectivity of the network, and provide theoretical guidance and practical basis for the monitoring of long oil and gas pipeline network, the city tap water pipe network and sewage pipe network.

A Methodology for Physical Interconnection Decisions of Next Generation Transport Networks

DEFF Research Database (Denmark)

Gutierrez Lopez, Jose Manuel; Riaz, M. Tahir; Madsen, Ole Brun

2011-01-01

of possibilities when designing the physical network interconnection. This paper develops and presents a methodology in order to deal with aspects related to the interconnection problem of optical transport networks. This methodology is presented as independent puzzle pieces, covering diverse topics going from......The physical interconnection for optical transport networks has critical relevance in the overall network performance and deployment costs. As telecommunication services and technologies evolve, the provisioning of higher capacity and reliability levels is becoming essential for the proper...... development of Next Generation Networks. Currently, there is a lack of specific procedures that describe the basic guidelines to design such networks better than "best possible performance for the lowest investment". Therefore, the research from different points of view will allow a broader space...

Panorama 2009 - greenhouse gas emissions and the transport sector

International Nuclear Information System (INIS)

2008-01-01

The fact that the transport sector is growing quickly brings advantages, such as quick access to any geographical location on earth, but also disadvantages: noise, congestion and polluting emissions such as carbon dioxide (CO 2 ), the greenhouse gas (GHG) primarily responsible for global warming. In the effort to bring GHG emissions under control, improving results in the transport sector is a prime long-term objective. What proportion of CO 2 emissions generated at global and national level are due to the road, air, maritime and rail transport sectors, respectively? What mechanisms can be used to reduce GHG emissions in the transport sector at large?

Optimization of the telecommunication network of a gas utility; Optimisation d'un reseau de telecommunications d'un operateur gazier

Energy Technology Data Exchange (ETDEWEB)

Vinas, Ch.; Abadie, J. [GSO, Gaz Sud-Ouest, 64 - Pau (France)

2001-07-01

The information system of Gaz du Sud-Ouest (GSO) utility, which includes the real time systems for the exploitation of the gas transport and distribution system and its management, is based on heterogenous and separated telecommunication infrastructures. A project has been started which aims at optimizing the architecture of this communication network taking into consideration the technical aspects but also the security and costs constraints. (J.S.)

Network simulation of nonstationary ionic transport through liquid junctions

International Nuclear Information System (INIS)

Castilla, J.; Horno, J.

1993-01-01

Nonstationary ionic transport across the liquid junctions has been studied using Network Thermodynamics. A network model for the time-dependent Nernst-Plack-Poisson system of equation is proposed. With this network model and the electrical circuit simulation program PSPICE, the concentrations, charge density, and electrical potentials, at short times, have been simulated for the binary system NaCl/NaCl. (Author) 13 refs

Greenhouse gas emissions from the production and use of alternative transport fuels

International Nuclear Information System (INIS)

Le Cornu, J.K.

1990-01-01

A number of the commonly proposed alternative transport fuels were ranked according to both the cumulative greenhouse gas emissions and the production costs incurred between the recovery of the prime resource and the fuel's end use by the Australian transport fleet. An examination of the emissions of each greenhouse gas at each production stage confirmed the common presumption that the low levels of secondary greenhouse gas emissions involved contribute little to the overall greenhouse impact of a fuel's production and use. From a greenhouse point of view the transport fuels studied could be reasonable well ranked by considering their carbon dioxide emissions alone. A possible exception may apply in the case of the compressed natural gas option, which may need to separate consideration of the effect of fugitive emissions of methane from gas distribution systems. An assumption involved in reaching this result was that nitrous oxide emissions, on which there was inadequate hard data, would not form more than 1% of the total nitrogen oxide emissions. At such an emission level it could contribute up to 5% of a fuel's total greenhouse impact. It is concluded that apart from some small niche opportunities, there is no Australian alternative transport fuel option whose production cost and greenhouse impact makes it one which policy should favour over other fuels. It is stressed that this is no more than a preliminary scouting study of generic options, which addresses only greenhouse issues. 17 refs., 1 tab., 8 figs

Complexity in human transportation networks: a comparative analysis of worldwide air transportation and global cargo-ship movements

Science.gov (United States)

Woolley-Meza, O.; Thiemann, C.; Grady, D.; Lee, J. J.; Seebens, H.; Blasius, B.; Brockmann, D.

2011-12-01

We present a comparative network-theoretic analysis of the two largest global transportation networks: the worldwide air-transportation network (WAN) and the global cargo-ship network (GCSN). We show that both networks exhibit surprising statistical similarities despite significant differences in topology and connectivity. Both networks exhibit a discontinuity in node and link betweenness distributions which implies that these networks naturally segregate into two different classes of nodes and links. We introduce a technique based on effective distances, shortest paths and shortest path trees for strongly weighted symmetric networks and show that in a shortest path tree representation the most significant features of both networks can be readily seen. We show that effective shortest path distance, unlike conventional geographic distance measures, strongly correlates with node centrality measures. Using the new technique we show that network resilience can be investigated more precisely than with contemporary techniques that are based on percolation theory. We extract a functional relationship between node characteristics and resilience to network disruption. Finally we discuss the results, their implications and conclude that dynamic processes that evolve on both networks are expected to share universal dynamic characteristics.

Risk Evaluation of Railway Coal Transportation Network Based on Multi Level Grey Evaluation Model

Science.gov (United States)

Niu, Wei; Wang, Xifu

2018-01-01

The railway transport mode is currently the most important way of coal transportation, and now China’s railway coal transportation network has become increasingly perfect, but there is still insufficient capacity, some lines close to saturation and other issues. In this paper, the theory and method of risk assessment, analytic hierarchy process and multi-level gray evaluation model are applied to the risk evaluation of coal railway transportation network in China. Based on the example analysis of Shanxi railway coal transportation network, to improve the internal structure and the competitiveness of the market.

Solution of weakly compressible isothermal flow in landfill gas collection networks

Science.gov (United States)

Nec, Y.; Huculak, G.

2017-12-01

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy-Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein.

Dynamic safety assessment of natural gas stations using Bayesian network

NARCIS (Netherlands)

Zarei, Esmaeil; Azadeh, Ali; Khakzad Rostami, N.; Mirzaei Aliabadi, Mostafa; Mohammadfam, Iraj

2017-01-01

Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been

French natural gas industry. Key-data 2000

International Nuclear Information System (INIS)

Anon.

2001-01-01

The year 2000 is the year of deregulation of the European gas market. This short article reports on some significant economical data taken from a brochure edited by the French gas association: transport of natural gas (main suppliers), network (pipelines, distribution system), consumption (industry, residential and tertiary sectors), uses (vehicles, cogeneration units), liquefied petroleum gases (consumption in residential-tertiary, industry, agriculture and automotive applications). (J.S.)

Worldwide natural gas pipeline situation. Sekai no tennen gas pipeline jokyo

Energy Technology Data Exchange (ETDEWEB)

Arimoto, T [Osaka Gas Co. Ltd., Osaka (Japan)

1993-03-01

Constructing natural gas pipelines in wide areas requires investments of a huge amount. Many countries are building natural gas supply infrastructures under public support as nations' basic policy of promoting use of natural gas. This paper describes the present conditions of building pipelines in Western Europe, the U.S.A., Korea and Taiwan. In Western Europe, transporting companies established in line with the national policy own trunk pipelines and storage facilities, and import and distribute natural gas. The U.S.A. has 2300 small and large pipeline companies bearing transportation business. Pipelines extend about 1.9 million kilometers in total, with trunk pipelines accounting for about 440,000 kilometers. The companies are given eminent domain for the right of way. Korea has a plan to build a pipeline network with a distance of 1600 kilometers in around 2000. Taiwan has completed trunk pipelines extending 330 kilometers in two years. In Japan, the industry is preparing draft plans for wide area pipeline construction. 5 figs., 1 tab.

An intermodal transportation geospatial network modeling for containerized soybean shipping

Directory of Open Access Journals (Sweden)

Xiang Liu

2017-06-01

Full Text Available Containerized shipping is a growing market for agricultural exports, particularly soybeans. In order to understand the optimal strategies for improving the United States’ economic competitiveness in this emerging market, this research develops an intermodal transportation network modeling framework, focusing on U.S. soybean container shipments. Built upon detailed modal cost analyses, a Geospatial Intermodal Freight Transportation (GIFT model has been developed to understand the optimal network design for U.S. soybean exports. Based on market demand and domestic supply figures, the model is able to determine which domestically produced soybeans should go to which foreign markets, and by which transport modes. This research and its continual studies, will provide insights into future policies and practices that can improve the transportation efficiency of soybean logistics.

Trans-European transport networks and urban systems in European Union

OpenAIRE

Maksin-Mićić Marija

2003-01-01

The trans-European transport network has different effects at interregional macro-regional and mezzo-regional level, and its effectiveness rises at the lower regional levels. Possible approaches to the trans-European transport network impact and effect survey and policy options have been pointed out. In that respect the brief review of survies, strategic framework and policies in European Union has been given. The importance of increased accessibility and mobility for regional expansion and f...

Consumption of natural gas on GRTgaz's territory - Year 2007

International Nuclear Information System (INIS)

2008-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents some key figures about GRTgaz activity in 2007: Gross consumption on GRTgaz's transmission system and associated, Change in gross and corrected consumptions on the GRTgaz network over the period 2006-2007, Quantities of natural gas transported each month by GRTgaz in 2007

Transport link scanner: simulating geographic transport network expansion through individual investments

Science.gov (United States)

Jacobs-Crisioni, C.; Koopmans, C. C.

2016-07-01

This paper introduces a GIS-based model that simulates the geographic expansion of transport networks by several decision-makers with varying objectives. The model progressively adds extensions to a growing network by choosing the most attractive investments from a limited choice set. Attractiveness is defined as a function of variables in which revenue and broader societal benefits may play a role and can be based on empirically underpinned parameters that may differ according to private or public interests. The choice set is selected from an exhaustive set of links and presumably contains those investment options that best meet private operator's objectives by balancing the revenues of additional fare against construction costs. The investment options consist of geographically plausible routes with potential detours. These routes are generated using a fine-meshed regularly latticed network and shortest path finding methods. Additionally, two indicators of the geographic accuracy of the simulated networks are introduced. A historical case study is presented to demonstrate the model's first results. These results show that the modelled networks reproduce relevant results of the historically built network with reasonable accuracy.

International transport of incandescent gas mantles - an incident

International Nuclear Information System (INIS)

Singh, Khaidem R.K.

2004-01-01

Consumer products, though contain small quantities of radioactive material, are designed and manufactured with reference to prescribed safety standards; and supplied for use in public domain. On the basis of the nature of the exposures associated with such practices, which are quite low, the Regulatory Authority exempts the practices from many of the regulatory requirements. As they are inherently safe for handling, transporting and use, they are exempted from some of the requirements under the provisions of the regulations on the transport of radioactive material. Though the basic meaning and purpose of a radioactivity-based consumer product are similar to other commodities, there is a need to transport the former as per the regulations for safe transport of radioactive material till the product reaches at end user. The strict adherence to the transport regulations during transport of the radioactivity-based consumer product would ensure smooth carriage particularly in international arena. On the basis of an incident that happened during the transport of consumer products, this paper analyzes the provisions relating to radioactivity-based consumer products as envisaged in the basic safety standards of IAEA and their transport, particularly for natural thorium based consumer product gas mantles. (author)

Locating inefficient links in a large-scale transportation network

Science.gov (United States)

Sun, Li; Liu, Like; Xu, Zhongzhi; Jie, Yang; Wei, Dong; Wang, Pu

2015-02-01

Based on data from geographical information system (GIS) and daily commuting origin destination (OD) matrices, we estimated the distribution of traffic flow in the San Francisco road network and studied Braess's paradox in a large-scale transportation network with realistic travel demand. We measured the variation of total travel time Δ T when a road segment is closed, and found that | Δ T | follows a power-law distribution if Δ T 0. This implies that most roads have a negligible effect on the efficiency of the road network, while the failure of a few crucial links would result in severe travel delays, and closure of a few inefficient links would counter-intuitively reduce travel costs considerably. Generating three theoretical networks, we discovered that the heterogeneously distributed travel demand may be the origin of the observed power-law distributions of | Δ T | . Finally, a genetic algorithm was used to pinpoint inefficient link clusters in the road network. We found that closing specific road clusters would further improve the transportation efficiency.

Oil Transport Networks in Europe

Directory of Open Access Journals (Sweden)

Igbal Guliyev

2014-01-01

Full Text Available The author examines the problems and prospects of crude oil and petroleum products transportation market on the European continent. Particular attention is paid to the possibilities of the planned pipeline routes and new supplies of oil and petroleum products. European Union countries have large reserves of hydrocarbons, but it is not enough to fully satisfy domestic consumption. Improved pipeline infrastructure both within the EU and oil pipelines from other countries is an important economic and social factor. Recent developments of this year especially emphasize the importance of strengthening the energy security in the foreign policy of the state. For transporting fuel energy in Europe used the following types of transport: marine (sea and river, truck, railway, and pipeline. It seems necessary to mention the fact that the role of pipeline transport is particularly high in the oil and gas industry. Pipeline transport has an important impact on the formation and developmen t of the fuel and energy complex of the state, as well as regions, as its integral part. An effective system of crude oil and petroleum products pipelines is an important tool for the implementation of public policies, policies at the EU level, allowing the country to regulate the supply of crude oil and petroleum products to the overseas and domestic markets.

Next Generation Reliable Transport Networks

DEFF Research Database (Denmark)

Zhang, Jiang

the wavelength and fiber assignment problem is proposed and implemented for avionic optical transport networks. Simulation results give out resource consumptions and prove the efficiency of the proposed mechanisms. Finally, a Home Environment Service Knowledge Management system is proposed. Through ontology...... technologies, a knowledge base is constructed to represent the whole information of a home environment. By applying the reasoner tool, the proposed system manages to keep the consistency in a home environment and helps all software configure and update procedures across multiple vendors....... of criticality and security, there are certain physical or logical segregation requirements between the avionic systems. Such segregations can be implemented on the proposed avionic networks with different hierarchies. In order to fulfill the segregation requirements, a tailored heuristic approach for solving...

Biogas in the natural gas distribution network; Biogas til nettet

Energy Technology Data Exchange (ETDEWEB)

Kvist Jensen, T.

2009-05-15

With the Danish 'Thorsoe Biogas Plant' as reference case, an assessment of the possibility of using the existing natural gas distribution network for distributing biogas was carried out. Technologies for and cost of upgrading biogas to natural gas quality are presented. Furthermore, a socio-economic analysis has been performed, including the Danish financial conditions, the market models, and the role of the natural gas distribution companies.

Cross-border trading and transmission networks. The natural gas experience

International Nuclear Information System (INIS)

Zavattoni, G.

1992-01-01

The volume and sources of gas imports to Europe and cross-border trading regulations for gas imports into and within Europe are outlined. The import of gas from Algeria to Italy is presented as a case study. It deals with the purchase contract, transmission through Tunisia, the crossing of the Strait of Sicily and transportation within Italy. The EC Transit Directive, the Draft Directive(s) on third party access and the impact of the directives on the gas market are then discussed. (UK)

An Artificial Neural Network Controller for Intelligent Transportation Systems Applications

Science.gov (United States)

1996-01-01

An Autonomous Intelligent Cruise Control (AICC) has been designed using a feedforward artificial neural network, as an example for utilizing artificial neural networks for nonlinear control problems arising in intelligent transportation systems appli...

Interconnection and power transportation networks: operation; Reseaux d'interconnexion et de transport: fonctionnement

Energy Technology Data Exchange (ETDEWEB)

Bornard, P. [Reseau de Transport d' Electricite (RTE), Div. Systeme Electrique, 92 - Paris la Defense (France); Pavard, M. [Electricite de France (EDF), 75 - Paris (France); Testud, G. [Reseau de Transport d' Electricite (RTE), Dept. Exploitation du Systeme Electrique, 92 - Paris la Defense (France)

2005-10-01

For economical or technical reasons, the power generation units are in general grouped together in the same geographical areas, while the consumption points are much more dispersed. The power transportation and interconnection networks ensure the link between the big generation areas and the big consumption areas, and also with other foreign networks. The network manager must keep the balance between the available offer and the potential demand and ensures the transit of energy between the production units and the end-users with respecting the contractual voltage and frequency ranges. Incidents must be mastered to limit the inconvenience to users and to avoid the complete collapse of the power transportation system. This article describes the operation of such systems: 1 - problems linked with networks operation; 2 - transits distribution: general problem, transmissible power in a power line, voltage drop, calculations of power distributions; 3 - voltage and frequency adjustments; 4 - operation in disturbed regime: mastery of common incidents, mechanisms of major incidents (operation of a power system in strongly disturbed regime), protection of the power system, recovery; 5 - conclusion. (J.S.)

Network harness: bundles of routes in public transport networks

Science.gov (United States)

Berche, B.; von Ferber, C.; Holovatch, T.

2009-12-01

Public transport routes sharing the same grid of streets and tracks are often found to proceed in parallel along shorter or longer sequences of stations. Similar phenomena are observed in other networks built with space consuming links such as cables, vessels, pipes, neurons, etc. In the case of public transport networks (PTNs) this behavior may be easily worked out on the basis of sequences of stations serviced by each route. To quantify this behavior we use the recently introduced notion of network harness. It is described by the harness distribution P(r, s): the number of sequences of s consecutive stations that are serviced by r parallel routes. For certain PTNs that we have analyzed we observe that the harness distribution may be described by power laws. These power laws indicate a certain level of organization and planning which may be driven by the need to minimize the costs of infrastructure and secondly by the fact that points of interest tend to be clustered in certain locations of a city. This effect may be seen as a result of the strong interdependence of the evolutions of both the city and its PTN. To further investigate the significance of the empirical results we have studied one- and two-dimensional models of randomly placed routes modeled by different types of walks. While in one dimension an analytic treatment was successful, the two dimensional case was studied by simulations showing that the empirical results for real PTNs deviate significantly from those expected for randomly placed routes.

Solution of weakly compressible isothermal flow in landfill gas collection networks

Energy Technology Data Exchange (ETDEWEB)

Nec, Y [Thompson Rivers University, Kamloops, British Columbia (Canada); Huculak, G, E-mail: cranberryana@gmail.com, E-mail: greg@gnhconsulting.ca [GNH Consulting, Delta, British Columbia (Canada)

2017-12-15

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy–Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein. (paper)

Solution of weakly compressible isothermal flow in landfill gas collection networks

International Nuclear Information System (INIS)

Nec, Y; Huculak, G

2017-01-01

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy–Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein. (paper)

Selective pumping in a network: insect-style microscale flow transport

International Nuclear Information System (INIS)

Aboelkassem, Yasser; Staples, Anne E

2013-01-01

A new paradigm for selective pumping of fluids in a complex network of channels in the microscale flow regime is presented. The model is inspired by internal flow distributions produced by the rhythmic wall contractions observed in many insect tracheal networks. The approach presented here is a natural extension of previous two-dimensional modeling of insect-inspired microscale flow transport in a single channel, and aims to manipulate fluids efficiently in microscale networks without the use of any mechanical valves. This selective pumping approach enables fluids to be transported, controlled and precisely directed into a specific branch in a network while avoiding other possible routes. In order to present a quantitative analysis of the selective pumping approach presented here, the velocity and pressure fields and the time-averaged net flow that are induced by prescribed wall contractions are calculated numerically using the method of fundamental solutions. More specifically, the Stokeslets-meshfree method is used in this study to solve the Stokes equations that govern the flow motions in a network with moving wall contractions. The results presented here might help in understanding some features of the insect respiratory system function and guide efforts to fabricate novel microfluidic devices for flow transport and mixing, and targeted drug delivery applications. (paper)

Charge transport in transparent single-wall carbon nanotube networks

International Nuclear Information System (INIS)

Jaiswal, Manu; Wang, Wei; Fernando, K A Shiral; Sun Yaping; Menon, Reghu

2007-01-01

We report the electric-field effects and magnetotransport in transparent networks of single-wall carbon nanotubes (SWNT). The temperature dependence of conductance of the network indicates a 2D Mott variable-range hopping (VRH) transport mechanism. Electric field and temperature are shown to have similar effects on the carrier hops and identical exponents for the conductance of the network are obtained from the high electric field and temperature dependences. A power-law temperature dependence with an exponent 3/2 for the threshold field is obtained and explained as a result of the competing contributions from electric field and phonons to the carrier hop. A negative magnetoresistance (MR) is observed at low temperatures, which arises from a forward interference scattering mechanism in the weak scattering limit, consistent with the VRH transport

Mixed Transportation Network Design under a Sustainable Development Perspective

Directory of Open Access Journals (Sweden)

Jin Qin

2013-01-01

Full Text Available A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%.

Mixed Transportation Network Design under a Sustainable Development Perspective

Science.gov (United States)

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%. PMID:23476142

Liberalising the European natural gas market

International Nuclear Information System (INIS)

Mulder, M.

2002-01-01

Europe's natural gas market is changing radically. The several national markets dominated by monopolistic suppliers are integrating into one European market in which production and trade are subject to competition, while transport through the networks will be unbundled and placed under regulatory influence. What will be the consequences of these changes on natural gas prices, supply security and the environment?

On the development and benchmarking of an approach to model gas transport in fractured media with immobile water storage

Science.gov (United States)

Harp, D. R.; Ortiz, J. P.; Pandey, S.; Karra, S.; Viswanathan, H. S.; Stauffer, P. H.; Anderson, D. N.; Bradley, C. R.

2017-12-01

In unsaturated fractured media, the rate of gas transport is much greater than liquid transport in many applications (e.g., soil vapor extraction operations, methane leaks from hydraulic fracking, shallow CO2 transport from geologic sequestration operations, and later-time radionuclide gas transport from underground nuclear explosions). However, the relatively immobile pore water can inhibit or promote gas transport for soluble constituents by providing storage. In scenarios with constant pressure gradients, the gas transport will be retarded. In scenarios with reversing pressure gradients (i.e. barometric pressure variations) pore water storage can enhance gas transport by providing a ratcheting mechanism. Recognizing the computational efficiency that can be gained using a single-phase model and the necessity of considering pore water storage, we develop a Richard's solution approach that includes kinetic dissolution/volatilization of constituents. Henry's Law governs the equilibrium gaseous/aqueous phase partitioning in the approach. The approach is implemented in a development branch of the PFLOTRAN simulator. We verify the approach with analytical solutions of: (1) 1D gas diffusion, (2) 1D gas advection, (3) sinusoidal barometric pumping of a fracture, and (4) gas transport along a fracture with uniform flow and diffusive walls. We demonstrate the retardation of gas transport in cases with constant pressure gradients and the enhancement of gas transport with reversing pressure gradients. The figure presents the verification of our approach to the analytical solution of barometric pumping of a fracture from Nilson et al (1991) where the x-axis "Horizontal axis" is the distance into the matrix block from the fracture.

CONSEQUENCES OF FAILURE OF GAS NETWORK INFRASTRUCTURE

Directory of Open Access Journals (Sweden)

Marek URBANIK

2016-06-01

Full Text Available Ecology today is becoming increasingly important. Increasing air pollution and greenhouse gas emissions make the search for such fuels which will not have such a negative effect on the environment as the fuel use currently - mainly coal. At present it seems that the substitute fuel can be gaseous fuels (propane-butane, methane. Their combustion is less harmful to the environment and their transport is relatively not very complicated. As it turns out, the use of gas is increasing in industry, automotive, heating systems (power plants that operate in the so-called cogeneration. The increase in demand carries continuous development of gas infrastructure, which in turn may increase probability of failure. As a conclusion of this article, taking into account all the construction disasters induced by the gas, the number of such failures is relatively small. It should be remembered, that the disaster caused by gas explosion may cause very large material and human losses. Not without significance is the impact of gas leakage, eg. of the pipeline on the environment. An example is the methane which is a greenhouse gas, less persistent in the air, but much more active than CO2. The article presents selected disasters associated with natural gas or propane-butane and the impact of these gases on the environment because these fuels are most commonly used in most sectors of the economy.

Key numbered-data of the French natural gas industry

International Nuclear Information System (INIS)

1999-01-01

The third edition of this folder contains the numbered data relative to the activity of the French natural gas industry in 1998 according to the information available in June 15, 1999. Consumption, sales and supplies data are presented for both natural gas and LPG fuel together with a map of the French natural gas transportation network. (J.S.)

Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

Energy Technology Data Exchange (ETDEWEB)

Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

2015-09-01

This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

Molecular transport network security using multi-wavelength optical spins.

Science.gov (United States)

Tunsiri, Surachai; Thammawongsa, Nopparat; Mitatha, Somsak; Yupapin, Preecha P

2016-01-01

Multi-wavelength generation system using an optical spin within the modified add-drop optical filter known as a PANDA ring resonator for molecular transport network security is proposed. By using the dark-bright soliton pair control, the optical capsules can be constructed and applied to securely transport the trapped molecules within the network. The advantage is that the dark and bright soliton pair (components) can securely propagate for long distance without electromagnetic interference. In operation, the optical intensity from PANDA ring resonator is fed into gold nano-antenna, where the surface plasmon oscillation between soliton pair and metallic waveguide is established.

Fiscal 2000 survey report. Feasibility study of reciprocative transportation system for carbon dioxide and natural gas utilizing gas hydrate; 2000 nendo gas hidrate wo riyosuru nisanka tanso to tennen gas no kogo yuso system no kanosei chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

A reciprocative CO2/CH{sub 4} transportation system will constitute a foundation on which minor gas fields may be made good use of in the Asia-Pacific region. For the construction of such a system, a survey is conducted into key technologies of separating CO2 from combustion exhaust with the aid of the hydrate process, reciprocative CO2/CH{sub 4} transportation with hydrate acting as medium, and subsurface CO2 storage and its utilization in minor gas fields or the like. The contents of the survey and the results fall in six areas, which are (1) the states of greenhouse gas reduction and natural gas utilization, (2) reciprocative CO2/CH{sub 4} transportation with hydrate acing as medium, (3) CO2 separation from combustion exhaust with the aid of the hydrate process, (4) reciprocative CO2/CH{sub 4} transportation with hydrate acing as medium, (5) subsurface CO2 storage and its utilization in minor gas fields, and (6) the establishment of a reciprocative CO2/CH{sub 4} transportation system and the evaluation of its cost performance. (NEDO)

Learning Data Set Influence on Identification Accuracy of Gas Turbine Neural Network Model

Science.gov (United States)

Kuznetsov, A. V.; Makaryants, G. M.

2018-01-01

There are many gas turbine engine identification researches via dynamic neural network models. It should minimize errors between model and real object during identification process. Questions about training data set processing of neural networks are usually missed. This article presents a study about influence of data set type on gas turbine neural network model accuracy. The identification object is thermodynamic model of micro gas turbine engine. The thermodynamic model input signal is the fuel consumption and output signal is the engine rotor rotation frequency. Four types input signals was used for creating training and testing data sets of dynamic neural network models - step, fast, slow and mixed. Four dynamic neural networks were created based on these types of training data sets. Each neural network was tested via four types test data sets. In the result 16 transition processes from four neural networks and four test data sets from analogous solving results of thermodynamic model were compared. The errors comparison was made between all neural network errors in each test data set. In the comparison result it was shown error value ranges of each test data set. It is shown that error values ranges is small therefore the influence of data set types on identification accuracy is low.

Pure- and Mixed-Gas Transport Study of Nafion® and Its Fe3+-Substituted Derivative for Membrane-Based Natural Gas Applications

KAUST Repository

Mukaddam, Mohsin Ahmed

2016-01-01

The focus of this research project was to develop a fundamental understanding of the structure-gas transport property relationship in Nafion® to investigate its potential use as a gas separation membrane material for natural gas (NG) applications

Selected Topics on Mass Transport in Gas-solid Interactions

DEFF Research Database (Denmark)

Somers, Marcel A.J.

2004-01-01

The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion-controlled d......The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion...... on the kinetics of phenomena in the solid state. Various experimental techniques were applied to investigate these phenomena; it is however beyond the scope of the present article to treat experimental conditions in detail. The interested reader is referred to the original work for in depth discussions...

Hub location problems in transportation networks

DEFF Research Database (Denmark)

Gelareh, Shahin; Nickel, Stefan

2011-01-01

In this paper we propose a 4-index formulation for the uncapacitated multiple allocation hub location problem tailored for urban transport and liner shipping network design. This formulation is very tight and most of the tractable instances for MIP solvers are optimally solvable at the root node....... also introduce fixed cost values for Australian Post (AP) dataset....

French natural gas industry statistics

International Nuclear Information System (INIS)

2004-01-01

The opening of the French natural gas market is effective since August 2000. In this context, some information, which were published in the past, have become confidential and strategic and can no longer be revealed. The data published in this 2004 edition concern only the years 2001 and 2002 for which data are available. The year 2000 inquiry could not be exploited. A first part presents the natural gas industry in France (consumption, supplies, production, storage, distribution, definition of gases, information sources, energy equivalence, map of transportation networks, storage, compression and production facilities). The statistical data are summarized in the second part in the form of tables: resources and uses in 1999, 2001 and 2002; sectoral use of the network distributed gas since 1972; regional distribution of gas production; domestic production and imports since 1972; sectoral distribution of network gas supplies; pipelines and distribution systems; personnel in the gas industry; gas supplies in 2002; supplies to the residential-tertiary sector in 2002; supplies to the industry in 2002; regional supplies in 2002; share of gas supplies per use in each region; regional distribution of gas supplies for each use. A comparison between the 2002 inquiry results and the provisional status is given in appendix. The 2002 energy status and the 2002 questionnaire are also given in appendixes. (J.S.)

A theoretical cost optimization model of reused flowback distribution network of regional shale gas development

International Nuclear Information System (INIS)

Li, Huajiao; An, Haizhong; Fang, Wei; Jiang, Meng

2017-01-01

The logistical issues surrounding the timing and transport of flowback generated by each shale gas well to the next is a big challenge. Due to more and more flowback being stored temporarily near the shale gas well and reused in the shale gas development, both transportation cost and storage cost are the heavy burden for the developers. This research proposed a theoretical cost optimization model to get the optimal flowback distribution solution for regional multi shale gas wells in a holistic perspective. Then, we used some empirical data of Marcellus Shale to do the empirical study. In addition, we compared the optimal flowback distribution solution by considering both the transportation cost and storage cost with the flowback distribution solution which only minimized the transportation cost or only minimized the storage cost. - Highlights: • A theoretical cost optimization model to get optimal flowback distribution solution. • An empirical study using the shale gas data in Bradford County of Marcellus Shale. • Visualization of optimal flowback distribution solutions under different scenarios. • Transportation cost is a more important factor for reducing the cost. • Help the developers to cut the storage and transportation cost of reusing flowback.

First in situ determination of gas transport coefficients (DO2, DAr and DN2) from bulk gas concentration measurements (O2, N2, Ar) in natural sea ice

DEFF Research Database (Denmark)

Crabeck, O.; Delille, B.; Rysgaard, Søren

2014-01-01

We report bulk gas concentrations of O2, N2, and Ar, as well as their transport coefficients, in natural landfast subarctic sea ice in southwest Greenland. The observed bulk ice gas composition was 27.5% O2, 71.4% N2, and 1.09% Ar. Most previous studies suggest that convective transport is the main...... driver of gas displacement in sea ice and have neglected diffusion processes. According to our data, brines were stratified within the ice, so that no convective transport could occur within the brine system. There- fore, diffusive transport was the main driver of gas migration. By analyzing the temporal...... evolution of an internal gas peak within the ice, we deduced the bulk gas transport coefficients for oxygen (DO2), argon (DAr), and nitrogen (DN2). The values fit to the few existing estimates from experimental work, and are close to the diffusivity values in water (1025 cm2 s21). We suggest that gas...

Field measurements of tracer gas transport by barometric pumping

International Nuclear Information System (INIS)

Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

1994-01-01

Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ''active'' tracer was driven by a large quantity of injected air; the second ''passive'' tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through ∼1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs

North American natural gas long-term outlook : market and transportation opportunities

International Nuclear Information System (INIS)

Mahan, R.

1998-01-01

This study assessed the impact of major issues and trends on the market dynamics of the natural gas industry. A view of how these trends may evolve over the 1998 to 2015 period was also presented. The focus of the study is on market and transportation opportunities in Canada and the United States and their relationship in terms of supply, demand and gas flows between large aggregated regions. Key issues addressed in the report include: (1) the impacts of new transportation capacity on the flow of gas among supply and demand regions, (2) the impact of deregulation and environmental issues on the demand for gas in the electricity generation sector, and (3) the impacts of technological innovations on supply cost and size of the resource base. The report predicts a steady increase ( about 2 per cent annually) in demand for natural gas in Canada over the projection period (i.e. 1998-2015). Highest growth rates are likely to occur in the use of natural gas to generate electricity. While Alberta will remain pre-eminent among producing regions, British Columbia and resource areas off Canada's East Coast will also significantly increase their share of Canada's total production. 36 refs., 64 tabs., 46 figs

Multi-agent model predictive control for transportation networks : Serial versus parallel schemes

NARCIS (Netherlands)

Negenborn, R.R.; De Schutter, B.; Hellendoorn, J.

2006-01-01

We consider the control of large-scale transportation networks, like road traffic networks, power distribution networks, water distribution networks, etc. Control of these networks is often not possible from a single point by a single intelligent control agent; instead control has to be performed

Development of a tracer transport option for the NAPSAC fracture network computer code

International Nuclear Information System (INIS)

Herbert, A.W.

1990-06-01

The Napsac computer code predicts groundwater flow through fractured rock using a direct fracture network approach. This paper describes the development of a tracer transport algorithm for the NAPSAC code. A very efficient particle-following approach is used enabling tracer transport to be predicted through large fracture networks. The new algorithm is tested against three test examples. These demonstrations confirm the accuracy of the code for simple networks, where there is an analytical solution to the transport problem, and illustrates the use of the computer code on a more realistic problem. (author)

Gas transport into a cavitation bubble during the explosion

International Nuclear Information System (INIS)

Oldenziel, D.M.

1976-01-01

When considering cavitation bubbles exploding from small stream nuclei the surface tension plays an important role, and mostly negative pressures exist in the surroundings of such a bubble. During the short explosion time, the gas and vapor pressure in the bubble plays no important role in the dynamic process. The high radial velocity of the bubble wall introduces a steep gradient in the concentration of dissolved air near it, which results in some enforced gas transport into the bubble. During the bubble implosion it is necessary to take into account the amount of gas in the bubble, as it certainly plays an important role in exploring the cavitation erosion. In this survey the solution of a mathematical model for the gas diffusion process is compared with some experimental results

A Highly Stable Microporous Covalent Imine Network Adsorbent for Natural Gas Upgrading and Flue Gas CO2 Capture

KAUST Repository

Das, Swapan Kumar; Wang, Xinbo; Ostwal, Mayur; Lai, Zhiping

2016-01-01

The feasible capture and separation of CO2 and N2 from CH4 is an important task for natural gas upgrading and the control of greenhouse gas emissions. Here, we studied the microporous covalent imine networks (CIN) material prepared through Schiff

Revisiting low-fidelity two-fluid models for gas-solids transport

Science.gov (United States)

Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

2016-08-01

Two-phase gas-solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas-solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe-Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

Three-Dimensional Network Model for Coupling of Fracture and Mass Transport in Quasi-Brittle Geomaterials

Directory of Open Access Journals (Sweden)

Peter Grassl

2016-09-01

Full Text Available Dual three-dimensional networks of structural and transport elements were combined to model the effect of fracture on mass transport in quasi-brittle geomaterials. Element connectivity of the structural network, representing elasticity and fracture, was defined by the Delaunay tessellation of a random set of points. The connectivity of transport elements within the transport network was defined by the Voronoi tessellation of the same set of points. A new discretisation strategy for domain boundaries was developed to apply boundary conditions for the coupled analyses. The properties of transport elements were chosen to evolve with the crack opening values of neighbouring structural elements. Through benchmark comparisons involving non-stationary transport and fracture, the proposed dual network approach was shown to be objective with respect to element size and orientation.

Blending Hydrogen into Natural Gas Pipeline Networks: A Review of Key Issues

Energy Technology Data Exchange (ETDEWEB)

Melaina, M. W.; Antonia, O.; Penev, M.

2013-03-01

The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest, four deliver natural gas from Canada, and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines.

Integrated transport code system for a multicomponent plasma in a gas dynamic trap

International Nuclear Information System (INIS)

Anikeev, A.V.; Karpushov, A.N.; Noak, K.; Strogalova, S.L.

2000-01-01

This report is focused on the development of the theoretical and numerical models of multicomponent high-β plasma confinement and transport in the gas-dynamic trap (GDT). In order to simulate the plasma behavior in the GDT as well as that in the GDT-based neutron source the Integrated Transport Code System is developed from existing stand-alone codes calculating the target plasma, the fast ions and the neutral gas in the GDT. The code system considers the full dependence of the transport phenomena on space, time, energy and angle variables as well as the interactions between the particle fields [ru

Gas Transport through Fractured Rock near the U20az Borehole, Pahute Mesa, Nevada.

Science.gov (United States)

Rockhold, M.; Lowrey, J. D.; Kirkham, R.; Olsen, K.; Waichler, S.; White, M. D.; Wurstner White, S.

2017-12-01

Field experiments were performed in 2012-13 and 2016-17 at the U-20az testbed at the Nevada National Security Site to develop and evaluate capabilities for monitoring and modeling noble gas transport associated with underground nuclear explosions (UNE). Experiments were performed by injecting both chemical (CF2BR2, SF6) and radioactive (37Ar, 127Xe) gas species into the deep subsurface at this legacy UNE site and monitoring the breakthrough of the gases at different locations on or near the ground surface. Gas pressures were also monitored in both the chimney and at ground surface. Field experiments were modeled using the parallel, non-isothermal, two-phase flow and transport simulator, STOMP-GT. A site conceptual-numerical model was developed from a geologic framework model, and using a dual-porosity/permeability model for the constitutive relative permeability-saturation-capillary pressure relations of the fractured rock units. Comparisons of observed and simulated gas species concentrations show that diffusion is a highly effective transport mechanism under ambient conditions in the water-unsaturated fractured rock. Over-pressurization of the cavity during one of the field campaigns, and barometric pressure fluctuations are shown to result in enhanced gas transport by advection through fractures.

Gas permeation through a polymer network

International Nuclear Information System (INIS)

Schmittmann, B; Gopalakrishnan, Manoj; Zia, R K P

2005-01-01

We study the diffusion of gas molecules through a two-dimensional network of polymers with the help of Monte Carlo simulations. The polymers are modelled as non-interacting random walks on the bonds of a two-dimensional square lattice, while the gas particles occupy the lattice cells. When a particle attempts to jump to a nearest-neighbour empty cell, it has to overcome an energy barrier which is determined by the number of polymer segments on the bond separating the two cells. We investigate the gas current J as a function of the mean segment density ρ, the polymer length l and the probability q m for hopping across m segments. Whereas J decreases monotonically with ρ for fixed l, its behaviour for fixed ρ and increasing ldepends strongly on q. For small, non-zero q, J appears to increase slowly with l. In contrast, for q = 0, it is dominated by the underlying percolation problem and can be non-monotonic. We provide heuristic arguments to put these interesting phenomena into context

Transport Network Technologies – Study and Testing

DEFF Research Database (Denmark)

Bozorgebrahimi, K.; Channegowda, M.; Colmenero, A.

Following on from the theoretical research into Carrier Class Transport Network Technologies (CCTNTs) documented in DJ1.1.1, this report describes the extensive testing performed by JRA1 Task 1. The tests covered EoMPLS, Ethernet OAM, Synchronous Ethernet, PBB-TE, MPLS-TP, OTN and GMPLS...

Improving estimates of subsurface gas transport in unsaturated fractured media using experimental Xe diffusion data and numerical methods

Science.gov (United States)

Ortiz, J. P.; Ortega, A. D.; Harp, D. R.; Boukhalfa, H.; Stauffer, P. H.

2017-12-01

Gas transport in unsaturated fractured media plays an important role in a variety of applications, including detection of underground nuclear explosions, transport from volatile contaminant plumes, shallow CO2 leakage from carbon sequestration sites, and methane leaks from hydraulic fracturing operations. Gas breakthrough times are highly sensitive to uncertainties associated with a variety of hydrogeologic parameters, including: rock type, fracture aperture, matrix permeability, porosity, and saturation. Furthermore, a couple simplifying assumptions are typically employed when representing fracture flow and transport. Aqueous phase transport is typically considered insignificant compared to gas phase transport in unsaturated fracture flow regimes, and an assumption of instantaneous dissolution/volatilization of radionuclide gas is commonly used to reduce computational expense. We conduct this research using a twofold approach that combines laboratory gas experimentation and numerical modeling to verify and refine these simplifying assumptions in our current models of gas transport. Using a gas diffusion cell, we are able to measure air pressure transmission through fractured tuff core samples while also measuring Xe gas breakthrough measured using a mass spectrometer. We can thus create synthetic barometric fluctuations akin to those observed in field tests and measure the associated gas flow through the fracture and matrix pore space for varying degrees of fluid saturation. We then attempt to reproduce the experimental results using numerical models in PLFOTRAN and FEHM codes to better understand the importance of different parameters and assumptions on gas transport. Our numerical approaches represent both single-phase gas flow with immobile water, as well as full multi-phase transport in order to test the validity of assuming immobile pore water. Our approaches also include the ability to simulate the reaction equilibrium kinetics of dissolution

Feedforward Nonlinear Control Using Neural Gas Network

Directory of Open Access Journals (Sweden)

Iván Machón-González

2017-01-01

Full Text Available Nonlinear systems control is a main issue in control theory. Many developed applications suffer from a mathematical foundation not as general as the theory of linear systems. This paper proposes a control strategy of nonlinear systems with unknown dynamics by means of a set of local linear models obtained by a supervised neural gas network. The proposed approach takes advantage of the neural gas feature by which the algorithm yields a very robust clustering procedure. The direct model of the plant constitutes a piece-wise linear approximation of the nonlinear system and each neuron represents a local linear model for which a linear controller is designed. The neural gas model works as an observer and a controller at the same time. A state feedback control is implemented by estimation of the state variables based on the local transfer function that was provided by the local linear model. The gradient vectors obtained by the supervised neural gas algorithm provide a robust procedure for feedforward nonlinear control, that is, supposing the inexistence of disturbances.

Steerable sound transport in a 3D acoustic network

Science.gov (United States)

Xia, Bai-Zhan; Jiao, Jun-Rui; Dai, Hong-Qing; Yin, Sheng-Wen; Zheng, Sheng-Jie; Liu, Ting-Ting; Chen, Ning; Yu, De-Jie

2017-10-01

Quasi-lossless and asymmetric sound transports, which are exceedingly desirable in various modern physical systems, are almost always based on nonlinear or angular momentum biasing effects with extremely high power levels and complex modulation schemes. A practical route for the steerable sound transport along any arbitrary acoustic pathway, especially in a three-dimensional (3D) acoustic network, can revolutionize the sound power propagation and the sound communication. Here, we design an acoustic device containing a regular-tetrahedral cavity with four cylindrical waveguides. A smaller regular-tetrahedral solid in this cavity is eccentrically emplaced to break spatial symmetry of the acoustic device. The numerical and experimental results show that the sound power flow can unimpededly transport between two waveguides away from the eccentric solid within a wide frequency range. Based on the quasi-lossless and asymmetric transport characteristic of the single acoustic device, we construct a 3D acoustic network, in which the sound power flow can flexibly propagate along arbitrary sound pathways defined by our acoustic devices with eccentrically emplaced regular-tetrahedral solids.

A turbulent transport network model in MULTIFLUX coupled with TOUGH2

International Nuclear Information System (INIS)

Danko, G.; Bahrami, D.; Birkholzer, J.T.

2011-01-01

A new numerical method is described for the fully iterated, conjugate solution of two discrete submodels, involving (a) a transport network model for heat, moisture, and airflows in a high-permeability, air-filled cavity; and (b) a variably saturated fractured porous medium. The transport network submodel is an integrated-parameter, computational fluid dynamics solver, describing the thermal-hydrologic transport processes in the flow channel system of the cavity with laminar or turbulent flow and convective heat and mass transport, using MULTIFLUX. The porous medium submodel, using TOUGH2, is a solver for the heat and mass transport in the fractured rock mass. The new model solution extends the application fields of TOUGH2 by integrating it with turbulent flow and transport in a discrete flow network system. We present demonstrational results for a nuclear waste repository application at Yucca Mountain with the most realistic model assumptions and input parameters including the geometrical layout of the nuclear spent fuel and waste with variable heat load for the individual containers. The MULTIFLUX and TOUGH2 model elements are fully iterated, applying a programmed reprocessing of the Numerical Transport Code Functionalization model-element in an automated Outside Balance Iteration loop. The natural, convective airflow field and the heat and mass transport in a representative emplacement drift during postclosure are explicitly solved in the new model. The results demonstrate that the direction and magnitude of the air circulation patterns and all transport modes are strongly affected by the heat and moisture transport processes in the surrounding rock, justifying the need for a coupled, fully iterated model solution such as the one presented in the paper.

Preliminary assessment of the availability of U.S. natural gas resources to meet U.S. transportation energy demand

International Nuclear Information System (INIS)

Singh, M. K.; Moore, J. S.

2002-01-01

Recent studies have indicated that substitutes for conventional petroleum resources will be needed to meet U.S. transportation energy demand in the first half of this century. One possible substitute is natural gas which can be used as a transportation fuel directly in compressed natural gas or liquefied natural gas vehicles or as resource fuel for the production of hydrogen for fuel cell vehicles. This paper contains a preliminary assessment of the availability of U.S. natural gas resources to meet future U.S. transportation fuel demand. Several scenarios of natural gas demand, including transportation demand, in the U.S. to 2050 are developed. Natural gas resource estimates for the U. S. are discussed. Potential Canadian and Mexican exports to the U.S. are estimated. Two scenarios of potential imports from outside North America are also developed. Considering all these potential imports, U.S. natural gas production requirements to 2050 to meet the demand scenarios are developed and compared with the estimates of U.S. natural gas resources. The comparison results in a conclusion that (1) given the assumptions made, there are likely to be supply constraints on the availability of U.S. natural gas supply post-2020 and (2) if natural gas use in transportation grows substantially, it will have to compete with other sectors of the economy for that supply-constrained natural gas

Regulatory aspects of the transportation of natural gas coming from marginal fields; Aspectos regulatorios do transporte de gas natural oriundo de campos marginais

Energy Technology Data Exchange (ETDEWEB)

Alpire, Ricardo [Universidade Salvador (UNIFACS), BA (Brazil); Tiryaki, Gisele Ferreira [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)

2010-07-01

Natural gas is an energy input that only recently began to have greater weight in the Brazilian energy matrix. The share of natural gas in national energy policies grew significantly between 1998 and 2009, reaching almost 10% of energetic participation in the end of this period. Because of this very dynamic and growing market, it is necessary to revisit the existing legislation to assess its relevance in the face of new conflict situations among experienced agents. This article aims to evaluate the existing legislation for the natural gas sector, particularly as to its effectiveness in regulating the conflicting issues in its distribution of this input in the form of compressed natural gas reserves come from marginal, where the final consumer is not located within the pipeline network of state distributor. Will address the standards in the industry, to the most recent law passed, Gas Law No. 11.909/2009, presented a critical review of the subject. (author)

The climatogenetic factors and the transport network

Directory of Open Access Journals (Sweden)

Vasile MAXIM

2010-03-01

Full Text Available The article analyses the climatogenic factors and how they influence the transport system (network of the Republic of Moldova. The following climatogenetic factors were analysed: dynamic, physical-geographic, etc. as well as some specific climatic elements as the temperature of the air, cloud amount, humidity, direction and speed of the wind. As a conclusion it can be mentioned that when tracing the terrestrial transport system it is necessary to take into consideration the climatic factors which directly influence this field of human activity.

The contribution of diffusion to methane transport in deep underground gas deposits; Der Beitrag der Diffusion zum Methantransport in tiefliegenden Gas-Lagerstaetten

Energy Technology Data Exchange (ETDEWEB)

Sachs, W. [Institut fuer Erdoel- und Erdgasforschung, Clausthal-Zellerfeld (Germany)

1998-12-31

Optimisation of gas production necessitates accurate knowledge of gas transport mechanisms. In view of the extreme temperatures, pressures, and permeability conditions of underground gas deposits, linear transfer of existing knowledge will be inappropriate. The author therefore uses a simple capillary bundle model with exemplary pressures, temperatures and permeabilities in order to assess the contribution of transport by diffusion. The diffusion coefficients, which are required for this and so far could not be measured under pressure, were determined by a new experimental method whose results will permit a better interpretation of the concentration dependence of the diffusion coefficient. The velocity of methane inflow and outflow in the water-filled pore space may provide knowledge on problems of gas storage in the pore space. (orig.) [Deutsch] Fuer den Foerderprozess und insbesondere seine Optimierung ist eine genaue Kenntnis der Transportmechanismen wesentlich. Unter den drastischen Bedingungen fuer Temperatur, Druck und Permeabilitaet tiefliegender Gas-Lagerstaetten mag die Uebertragung der bisherigen Vorstellungen ueber den Transport in der Lagerstaette zu einer unvollstaendigen Beschreibung fuehren. Unter Anwendung eines einfachen Kapillarbuendelmodells wird mit Beispielen fuer Druck, Temperatur und Permeabilitaet der moegliche Beitrag des Transports durch Diffusion abgeschaetzt. Zur Bestimmung der hierfuer notwendigen und bisher unter Druckbeaufschlagung nicht gemessenen Diffusionskoeffizienten wurde eine neue experimentelle Methode angewandt, deren Ergebnisse eine weiterfuehrende Interpretation der Konzentrationsabhaengigkeit des Diffusionskoeffizienten ermoeglichen. Auch fuer Fragestellungen der Speicherung von Gas im Porenraum kann die Geschwindigkeit der Ein- und Ausloesung von Methan im wasserhaltigen Porenraum von Interesse sein. (orig.)

Operator splitting method for simulation of dynamic flows in natural gas pipeline networks

Science.gov (United States)

Dyachenko, Sergey A.; Zlotnik, Anatoly; Korotkevich, Alexander O.; Chertkov, Michael

2017-12-01

We develop an operator splitting method to simulate flows of isothermal compressible natural gas over transmission pipelines. The method solves a system of nonlinear hyperbolic partial differential equations (PDEs) of hydrodynamic type for mass flow and pressure on a metric graph, where turbulent losses of momentum are modeled by phenomenological Darcy-Weisbach friction. Mass flow balance is maintained through the boundary conditions at the network nodes, where natural gas is injected or withdrawn from the system. Gas flow through the network is controlled by compressors boosting pressure at the inlet of the adjoint pipe. Our operator splitting numerical scheme is unconditionally stable and it is second order accurate in space and time. The scheme is explicit, and it is formulated to work with general networks with loops. We test the scheme over range of regimes and network configurations, also comparing its performance with performance of two other state of the art implicit schemes.

The shortest path algorithm performance comparison in graph and relational database on a transportation network

Directory of Open Access Journals (Sweden)

Mario Miler

2014-02-01

Full Text Available In the field of geoinformation and transportation science, the shortest path is calculated on graph data mostly found in road and transportation networks. This data is often stored in various database systems. Many applications dealing with transportation network require calculation of the shortest path. The objective of this research is to compare the performance of Dijkstra shortest path calculation in PostgreSQL (with pgRouting and Neo4j graph database for the purpose of determining if there is any difference regarding the speed of the calculation. Benchmarking was done on commodity hardware using OpenStreetMap road network. The first assumption is that Neo4j graph database would be well suited for the shortest path calculation on transportation networks but this does not come without some cost. Memory proved to be an issue in Neo4j setup when dealing with larger transportation networks.

Artificial neural networks application for horizontal and vertical forecasting radionuclides transport

International Nuclear Information System (INIS)

Khil'ko, O.S.; Kovalenko, V.I.; Kundas, S.P.

2010-01-01

Artificial neural networks approach for horizontal and vertical radionuclide transport forecasting was proposed. Runoff factors analysis was considered. Additional artificial neural network structures for physical-chemical properties recognition were used. (authors)

The 'new' occupation of network manager

International Nuclear Information System (INIS)

Vivies, P. de; Von Burchardt, F.; Cattoor, H.; Mendiluce, J.; Vercammen, F.

2003-01-01

This paper gathers 5 presentations given at the 2003 gas congress of Paris about the network management activity. The first presentation presents the point of view of the commission of energy regulation (CRE) about the opening of the gas market, the tariffing of gas network access, the transparency about the available capacities, the opening of the professionals market to competition and the works in progress. The second presentation deals with the evolution of the gas transport activity in Germany. The third presentation presents the EASEE-gas association for the development of common commercial practices in the European gas market. The forth presentation treats of the evolution of the Spanish gas distribution market, while the last presentation presents the evolution of the liquefied petroleum gases (LPG) sector with the example of the supply of Hiddensee island in the Baltic sea. (J.S.)

Economic and reliability analysis in determining a programme for the technological renovation of gas networks

International Nuclear Information System (INIS)

Nkokolo, F.; Pisino, F.; Vakka, L.

1997-01-01

Gas Distribution Companies have long paid great attention to improving the quality of gas supply service to the consumer. This has involved them in an on-going attempt to successfully define and establish a clear computer assisted replacement programme which, when drawn up on a reliability basis, may also prove cost effective. The reasons which drive any gas line replacement programme are mainly related to the necessity: to improve the gas network asset so as to face a striking expected growth in gas demand; to refurbish old distribution systems with the purpose not only to increase the reliability and continuity of gas supply but also to reduce the rate of maintenance costs due to frequent repair works; to prevent the possibility of massive replacement works for a progressing ageing of the network. This paper will present the computer assisted procedure being implemented by Italgas. It ranks well defined network areas which urgently need renewal and also have a favourable economic index for action. The results of the analysis performed on a trial model network managed by the Geographic Information System, will also be a topic for discussion. (au)

Analytical transport network theory to guide the design of 3-D microstructural networks in energy materials: Part 1. Flow without reactions

Science.gov (United States)

Cocco, Alex P.; Nakajo, Arata; Chiu, Wilson K. S.

2017-12-01

We present a fully analytical, heuristic model - the "Analytical Transport Network Model" - for steady-state, diffusive, potential flow through a 3-D network. Employing a combination of graph theory, linear algebra, and geometry, the model explicitly relates a microstructural network's topology and the morphology of its channels to an effective material transport coefficient (a general term meant to encompass, e.g., conductivity or diffusion coefficient). The model's transport coefficient predictions agree well with those from electrochemical fin (ECF) theory and finite element analysis (FEA), but are computed 0.5-1.5 and 5-6 orders of magnitude faster, respectively. In addition, the theory explicitly relates a number of morphological and topological parameters directly to the transport coefficient, whereby the distributions that characterize the structure are readily available for further analysis. Furthermore, ATN's explicit development provides insight into the nature of the tortuosity factor and offers the potential to apply theory from network science and to consider the optimization of a network's effective resistance in a mathematically rigorous manner. The ATN model's speed and relative ease-of-use offer the potential to aid in accelerating the design (with respect to transport), and thus reducing the cost, of energy materials.

The Swiss Education and Research Network - SWITCH - Upgrades Optical Network to Transport 10 Gbps Using Sorrento Networks DWDM Platform

CERN Multimedia

2003-01-01

"Sorrento Networks, a supplier of optical transport networking equipment for carriers and enterprises worldwide, today announced that SWITCH successfully completed 10 Gbps BER tests on the 220 km Zurich to Manno and 360 km Zurich to Geneva links in September and November 2003, using Sorrento's GigaMux DWDM system" (1/2 page).

Factsheet 2011. Quality Regional Management for Electricity and Natural Gas Transport Networks; Factsheet 2011. Kwaliteit Regionaal Netbeheer Elektriciteitsnetten en Gastransportnetten

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-15

Regional grid operators take care of distribution of electricity and gas for households and small and medium-sized businesses. Moreover, they are responsible for monitoring and maintaining their grids. The Dutch Office of Energy Regulation supervises the quality of the grids of the grid operators. The Dutch Office of Energy Regulation considers quality to consist of four aspects: security of transport, safety, product quality and services quality. The Factsheets offer insight in how a grid operator has performed in recent years. By publishing the Factsheets on Quality, the Dutch Office of Energy Regulation aims to offer an objective, broad view on the realized quality by the grid operators [Dutch] Regionale netbeheerders verzorgen het transport van elektriciteit en gas voor onder andere huishoudens en het midden- en kleinbedrijf. Ze zijn daarnaast verantwoordelijk voor het onderhoud en de instandhouding van hun netten. De Energiekamer NMa houdt toezicht op de kwaliteit van de netten van netbeheerders. Onder kwaliteit verstaat de Energiekamer NMa vier aspecten: transportzekerheid, veiligheid, productkwaliteit en kwaliteit van dienstverlening. De Factsheets geven inzicht in hoe een netbeheerder gedurende de afgelopen jaren gepresteerd heeft. Met het publiceren van de Factsheets Kwaliteit beoogt de Energiekamer NMa een objectief en breed beeld van de gerealiseerde kwaliteit door netbeheerders te geven.

Computation of optimal transport and related hedging problems via penalization and neural networks

OpenAIRE

Eckstein, Stephan; Kupper, Michael

2018-01-01

This paper presents a widely applicable approach to solving (multi-marginal, martingale) optimal transport and related problems via neural networks. The core idea is to penalize the optimization problem in its dual formulation and reduce it to a finite dimensional one which corresponds to optimizing a neural network with smooth objective function. We present numerical examples from optimal transport, martingale optimal transport, portfolio optimization under uncertainty and generative adversa...

2006 statistical data of the French gas industry; Statistiques 2006 de l'industrie gaziere en France

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-12-15

This document makes a synthesis of the 2006 results of the annual inquiry about the French natural gas industry: 1 - organization of the French gas market (production, transport, methane terminals, storage facilities, distribution, commercialization, main steps of the opening of the gas market in France); 2 - the 2006 gas year (consumption, imports, production, stockpiles); 3 - results of the 2006 inquiry: infrastructures (storage capacities, pipelines and distribution network), production (evolution of natural gas and industrial gases production, uses), transport (inputs and outputs, geographical origin of inputs in 2005 and 2006, raw imports evolution since 1973), storage (evolution of stockpiles variation), natural gas supplies (sectoral uses), supplies by region and by sector in 2006, consumption by sector; 4 - power generation by gas cogeneration in 2005 (plants characteristics, classification, cogeneration status (in TWh), regional distribution of plants); 5 - 2006 monthly changes (inputs, net imports, consumption and useful stockpile, consumption and net imports); 6 - international comparisons (gas share in the overall energy consumption, consumption per user, evolution of main sectors of consumption in some European countries since 1973); 7 - appendixes: French transportation network, main gas roads in Europe, European gas fluxes, 2006 energy status, gas statuses during the past three years. (J.S.)

Large-scale transportation network congestion evolution prediction using deep learning theory.

Science.gov (United States)

Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

2015-01-01

Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation.

User-based representation of time-resolved multimodal public transportation networks.

Science.gov (United States)

Alessandretti, Laura; Karsai, Márton; Gauvin, Laetitia

2016-07-01

Multimodal transportation systems, with several coexisting services like bus, tram and metro, can be represented as time-resolved multilayer networks where the different transportation modes connecting the same set of nodes are associated with distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geo-localized transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, we provide a novel user-based representation of public transportation systems, which combines representations, accounting for the presence of multiple lines and reducing the effect of spatial embeddedness, while considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. After the adjustment of earlier techniques to the novel representation framework, we analyse the public transportation systems of several French municipal areas and identify hidden patterns of privileged connections. Furthermore, we study their efficiency as compared to the commuting flow. The proposed representation could help to enhance resilience of local transportation systems to provide better design policies for future developments.

Space evolution model and empirical analysis of an urban public transport network

Science.gov (United States)

Sui, Yi; Shao, Feng-jing; Sun, Ren-cheng; Li, Shu-jing

2012-07-01

This study explores the space evolution of an urban public transport network, using empirical evidence and a simulation model validated on that data. Public transport patterns primarily depend on traffic spatial-distribution, demands of passengers and expected utility of investors. Evolution is an iterative process of satisfying the needs of passengers and investors based on a given traffic spatial-distribution. The temporal change of urban public transport network is evaluated both using topological measures and spatial ones. The simulation model is validated using empirical data from nine big cities in China. Statistical analyses on topological and spatial attributes suggest that an evolution network with traffic demands characterized by power-law numerical values which distribute in a mode of concentric circles tallies well with these nine cities.

Reducing the Green House Gas Emissions from the Transportation Sector

Directory of Open Access Journals (Sweden)

Oyewande Akinnikawe

2010-02-01

Full Text Available In the United States, two thirds of the carbon monoxide and about one third of carbon dioxide emissions come from the transportation sector. Ways to reduce these emissions in the future include replacing gasoline and diesel by biofuels, or by blend of biofuels with conventional gasoline and diesel, or by compressed natural gas (CNG, or by replacing internal combustion engines by electric motors powered by hydrogen fuel cells or battery-powered electric vehicles recharged from the electric grid. This presentation will review these technologies the fuel production pathways, when they are likely to be available, and by what fraction transportation sector green house gas emissions could be reduced by each. A well-to-wheels (WTW analysis is performed on each vehicle/ fuel technology using the GREET model and the total energy use, the CO 2 emissions, NO x emissions, SO x emissions for the life cycle of the vehicle technologies are calculated. Prospects for reducing foreign oil dependence as well as mitigating green house gases emission from the transportation sector will be considered in the analysis.

Understanding of Neutral Gas Transport in the Alcator C-Mod Tokamak Divertor

International Nuclear Information System (INIS)

Stotler, D.P.; Pitcher, C.S.; Boswell, C.J.; LaBombard, B.; Terry, J.L.; Elder, J.D.; Lisgo, S.

2002-01-01

A series of experiments on the effect of divertor baffling on the Alcator C-Mod tokamak provides stringent tests on models of neutral gas transport in and around the divertor region. One attractive feature of these experiments is that a trial description of the background plasma can be constructed from experimental measurements using a simple model, allowing the neutral gas transport to be studied with a stand-alone code. The neutral-ion and neutral-neutral elastic scattering processes recently added to the DEGAS 2 Monte Carlo neutral transport code permit the neutral gas flow rates between the divertor and main chamber to be simulated more realistically than before. Nonetheless, the simulated neutral pressures are too low and the deuterium Balmer-alpha emission profiles differ qualitatively from those measured, indicating an incomplete understanding of the physical processes involved in the experiment. Some potential explanations are examined and opportunities for future exploration a re highlighted. Improvements to atomic and surface physics data and models will play a role in the latter

MODELS AND METHODS FOR LOGISTICS HUB LOCATION: A REVIEW TOWARDS TRANSPORTATION NETWORKS DESIGN

Directory of Open Access Journals (Sweden)

Carolina Luisa dos Santos Vieira

Full Text Available ABSTRACT Logistics hubs affect the distribution patterns in transportation networks since they are flow-concentrating structures. Indeed, the efficient moving of goods throughout supply chains depends on the design of such networks. This paper presents a literature review on the logistics hub location problem, providing an outline of modeling approaches, solving techniques, and their applicability to such context. Two categories of models were identified. While multi-criteria models may seem best suited to find optimal locations, they do not allow an assessment of the impact of new hubs on goods flow and on the transportation network. On the other hand, single-criterion models, which provide location and flow allocation information, adopt network simplifications that hinder an accurate representation of the relationshipbetween origins, destinations, and hubs. In view of these limitations we propose future research directions for addressing real challenges of logistics hubs location regarding transportation networks design.

Networking for large-scale science: infrastructure, provisioning, transport and application mapping

International Nuclear Information System (INIS)

Rao, Nageswara S; Carter, Steven M; Wu Qishi; Wing, William R; Zhu Mengxia; Mezzacappa, Anthony; Veeraraghavan, Malathi; Blondin, John M

2005-01-01

Large-scale science computations and experiments require unprecedented network capabilities in the form of large bandwidth and dynamically stable connections to support data transfers, interactive visualizations, and monitoring and steering operations. A number of component technologies dealing with the infrastructure, provisioning, transport and application mappings must be developed and/or optimized to achieve these capabilities. We present a brief account of the following technologies that contribute toward achieving these network capabilities: (a) DOE UltraScienceNet and NSF CHEETAH network testbeds that provide on-demand and scheduled dedicated network connections; (b) experimental results on transport protocols that achieve close to 100% utilization on dedicated 1Gbps wide-area channels; (c) a scheme for optimally mapping a visualization pipeline onto a network to minimize the end-to-end delays; and (d) interconnect configuration and protocols that provides multiple Gbps flows from Cray X1 to external hosts

Networking for large-scale science: infrastructure, provisioning, transport and application mapping

Energy Technology Data Exchange (ETDEWEB)

Rao, Nageswara S [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Carter, Steven M [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wu Qishi [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wing, William R [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhu Mengxia [Department of Computer Science, Louisiana State University, Baton Rouge, LA 70803 (United States); Mezzacappa, Anthony [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Veeraraghavan, Malathi [Department of Computer Science, University of Virginia, Charlottesville, VA 22904 (United States); Blondin, John M [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States)

2005-01-01

Large-scale science computations and experiments require unprecedented network capabilities in the form of large bandwidth and dynamically stable connections to support data transfers, interactive visualizations, and monitoring and steering operations. A number of component technologies dealing with the infrastructure, provisioning, transport and application mappings must be developed and/or optimized to achieve these capabilities. We present a brief account of the following technologies that contribute toward achieving these network capabilities: (a) DOE UltraScienceNet and NSF CHEETAH network testbeds that provide on-demand and scheduled dedicated network connections; (b) experimental results on transport protocols that achieve close to 100% utilization on dedicated 1Gbps wide-area channels; (c) a scheme for optimally mapping a visualization pipeline onto a network to minimize the end-to-end delays; and (d) interconnect configuration and protocols that provides multiple Gbps flows from Cray X1 to external hosts.

Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High-Performance Gas Sensing.

Science.gov (United States)

Wan, Pengbo; Wen, Xuemei; Sun, Chaozheng; Chandran, Bevita K; Zhang, Han; Sun, Xiaoming; Chen, Xiaodong

2015-10-28

A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical Simulation of Flow and Suspended Sediment Transport in the Distributary Channel Networks

Directory of Open Access Journals (Sweden)

Wei Zhang

2014-01-01

Full Text Available Flow and suspended sediment transport in distributary channel networks play an important role in the evolution of deltas and estuaries, as well as the coastal environment. In this study, a 1D flow and suspended sediment transport model is presented to simulate the hydrodynamics and suspended sediment transport in the distributary channel networks. The governing equations for river flow are the Saint-Venant equations and for suspended sediment transport are the nonequilibrium transport equations. The procedure of solving the governing equations is firstly to get the matrix form of the water level and suspended sediment concentration at all connected junctions by utilizing the transformation of the governing equations of the single channel. Secondly, the water level and suspended sediment concentration at all junctions can be obtained by solving these irregular spare matrix equations. Finally, the water level, discharge, and suspended sediment concentration at each river section can be calculated. The presented 1D flow and suspended sediment transport model has been applied to the Pearl River networks and can reproduce water levels, discharges, and suspended sediment concentration with good accuracy, indicating this that model can be used to simulate the hydrodynamics and suspended sediment concentration in the distributary channel networks.

Possibilities of using liquefied oil gas in transport

Directory of Open Access Journals (Sweden)

A. Kuprys

2009-03-01

Full Text Available The trends of the input of an alternative type of fuel in the transport system of the European Union are analysed. Taking into account the measures of promoting liquefied petroleum gas (LPG consumption in road transport, a bundle of specific variables was analysed to understand the consumers for making decision to use LPG in cars. It is revealed that the obtained models enable to evaluate the behaviour of consumers and conditioning transition to using an alternative type of fuel in transport industry. The proposed models were assessed conducting statistic and sensitivity analysis. The pay-off of the additional equipment of the car was analysed considering the driven distance with an alternative type of fuel. The pay-off analysis of supplementary equipment depending on the ratio of standard and alternative fuel prices is presented.

Secure and economic operational of a gas transportation system; Operacion economica y segura de un sistema de transporte de gas

Energy Technology Data Exchange (ETDEWEB)

Sardi, Oscar Jose; Trichilo, Claudia; Valpreda, Carlos [Transportadora de Gas del Sur S.A. (Argentina)

2003-07-01

Since 1992, Transportadora de Gas del Sur (TGS) has been operating the longest gas pipeline system in South America. Prior to that date, the system was managed by GE, a state-owned company. Early on in the administration of the company, some improvement opportunities were identified in the technical, commercial, management and personnel fields. An integrated transformation process was developed which involved major investments, acquisition of new technology, re-design of the work force, and new work methodologies. The course of action followed by the company was based on an attempt to achieve permanent improvement on business results. This paper is the result of the improvements applied to our gas transportation system. Due to the time and cost assessment required by scheduled turbine compressor maintenance works (83 - 538.220 hp), a Contingency Plan for turbine compressor breakdowns was established as well as an Economic Dispatch, which can determine low-cost operations in specific periods of time (during the year). This work details the actions taken. (author)

OTN Transport of Baseband Radio Serial Protocols in C-RAN Architecture for Mobile Network Applications

DEFF Research Database (Denmark)

Checko, Aleksandra; Kardaras, Georgios; Lanzani, Christian Fabio Alessandro

This white paper presents a proof of concept implementation of digital baseband radio data transport over Optical Transport Network (OTN) compliant to 3GPP Long Term Evolution – Advanced (LTE-A) standard enabling Cloud Radio Access Network (C-RAN) architecture. The transport between the baseband ...

A Visual Analytics Technique for Identifying Heat Spots in Transportation Networks

Directory of Open Access Journals (Sweden)

Marian Sorin Nistor

2016-12-01

Full Text Available The decision takers of the public transportation system, as part of urban critical infrastructures, need to increase the system resilience. For doing so, we identified analysis tools for biological networks as an adequate basis for visual analytics in that domain. In the paper at hand we therefore translate such methods for transportation systems and show the benefits by applying them on the Munich subway network. Here, visual analytics is used to identify vulnerable stations from different perspectives. The applied technique is presented step by step. Furthermore, the key challenges in applying this technique on transportation systems are identified. Finally, we propose the implementation of the presented features in a management cockpit to integrate the visual analytics mantra for an adequate decision support on transportation systems.

Secure Media Independent Handover Message Transport in Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Cho Choong-Ho

2009-01-01

Full Text Available The IEEE 802.21 framework for Media Independent Handover (MIH provides seamless vertical handover support for multimode mobile terminals. MIH messages are exchanged over various wireless media between mobile terminals and access networks to facilitate seamless handover. This calls for the need to secure MIH messages against network security threats in the wireless medium. In this paper, we first analyze IPSec/IKEv2 and DTLS security solution for secure MIH message transport. We show that handover latency can be an impediment to the use of IPSec and DTLS solutions. To overcome the handover overhead and hence minimize authentication time, a new secure MIH message transport solution, referred as MIHSec in this paper, is proposed. Experimental results are obtained for MIH between WLAN and Ethernet networks and the impacts of MIH message security on the handover latency are evaluated for IPSec, DTLS, and MIHSec security solutions. The effectiveness of MIHSec is demonstrated.

Railway optimal network simulation for the development of regional transport-logistics system

Directory of Open Access Journals (Sweden)

Mikhail Borisovich Petrov

2013-12-01

Full Text Available The dependence of logistics on mineral fuel is a stable tendency of regions development, though when making strategic plans of logistics in the regions, it is necessary to provide the alternative possibilities of power-supply sources change together with population density, transport infrastructure peculiarities, and demographic changes forecast. On the example of timber processing complex of the Sverdlovsk region, the authors suggest the algorithm of decision of the optimal logistics infrastructure allocation. The problem of regional railway network organization at the stage of slow transition from the prolonged stagnation to the new development is carried out. The transport networks’ configurations of countries on the Pacific Rim, which successfully developed nowadays, are analyzed. The authors offer some results of regional transport network simulation on the basis of artificial intelligence method. These methods let to solve the task with incomplete data. The ways of the transport network improvement in the Sverdlovsk region are offered.

Building the gas sector in Mexico

International Nuclear Information System (INIS)

Navarrete, J.E.

1996-01-01

Hydrocarbon reserves in Mexico, ranked 8th in the world, were discussed. On January 1, 1996, Mexico's hydrocarbon proven reserves were 62.1 billion barrels ( a decline of some 10 billion barrels since 1984). Of this 48.8 billion corresponded to crude oil and 13.3 billion to natural gas. Mexico's natural gas pipeline network includes 10,280 kilometres in transmission and 2,211 kilometres in distribution, concentrated along the Gulf of Mexico and in the central and northern regions of the country. A new regulatory framework for natural gas, passed in Congress in 1995, was outlined. The new amendments were designed to strengthen the natural gas industry through private investment in the storage, transportation and distribution of natural gas. Stages for third party access were identified. Increased North American regional integration by interconnections between Mexican, American and Canadian pipeline networks, and the effects of such integration on investments, were examined. figs

The regulation of transportation contracts for natural gas: the issue of contractual dirigisme; A regulacao dos contratos de transporte de gas natural: a questao do dirigismo contratual

Energy Technology Data Exchange (ETDEWEB)

Queiroz, Lizziane Souza; Siqueira, Mariana; Vasconcellos, Mariana Vannucci [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2004-07-01

The old principals that that rules the liberal idea of contract are replaced for a new Theory that allows the State to interfere in the private sector to please the public interest. The Gas Transport Contract has the influence of open access and its public regulation is necessary to provide the most important needs of Brazilian market. After this word about the problem, we realize the meaning of the public intervention on the Transport Contracts to protect the nation's interests and to limit the private power. This paper try to clear the meaning of the contracts regulation to the gas natural market and its influence in a Brazilian interests. (author)

Mean-field Theory for Some Bus Transport Networks with Random Overlapping Clique Structure

International Nuclear Information System (INIS)

Yang Xuhua; Sun Bao; Wang Bo; Sun Youxian

2010-01-01

Transport networks, such as railway networks and airport networks, are a kind of random network with complex topology. Recently, more and more scholars paid attention to various kinds of transport networks and try to explore their inherent characteristics. Here we study the exponential properties of a recently introduced Bus Transport Networks (BTNs) evolution model with random overlapping clique structure, which gives a possible explanation for the observed exponential distribution of the connectivities of some BTNs of three major cities in China. Applying mean-field theory, we analyze the BTNs model and prove that this model has the character of exponential distribution of the connectivities, and develop a method to predict the growth dynamics of the individual vertices, and use this to calculate analytically the connectivity distribution and the exponents. By comparing mean-field based theoretic results with the statistical data of real BTNs, we observe that, as a whole, both of their data show similar character of exponential distribution of the connectivities, and their exponents have same order of magnitude, which show the availability of the analytical result of this paper. (general)

Visibility graph network analysis of natural gas price: The case of North American market

Science.gov (United States)

Sun, Mei; Wang, Yaqi; Gao, Cuixia

2016-11-01

Fluctuations in prices of natural gas significantly affect global economy. Therefore, the research on the characteristics of natural gas price fluctuations, turning points and its influencing cycle on the subsequent price series is of great significance. Global natural gas trade concentrates on three regional markets: the North American market, the European market and the Asia-Pacific market, with North America having the most developed natural gas financial market. In addition, perfect legal supervision and coordinated regulations make the North American market more open and more competitive. This paper focuses on the North American natural gas market specifically. The Henry Hub natural gas spot price time series is converted to a visibility graph network which provides a new direction for macro analysis of time series, and several indicators are investigated: degree and degree distribution, the average shortest path length and community structure. The internal mechanisms underlying price fluctuations are explored through the indicators. The results show that the natural gas prices visibility graph network (NGP-VGN) is of small-world and scale-free properties simultaneously. After random rearrangement of original price time series, the degree distribution of network becomes exponential distribution, different from the original ones. This means that, the original price time series is of long-range negative correlation fractal characteristic. In addition, nodes with large degree correspond to significant geopolitical or economic events. Communities correspond to time cycles in visibility graph network. The cycles of time series and the impact scope of hubs can be found by community structure partition.

Spatial-temporal data model and fractal analysis of transportation network in GIS environment

Science.gov (United States)

Feng, Yongjiu; Tong, Xiaohua; Li, Yangdong

2008-10-01

How to organize transportation data characterized by multi-time, multi-scale, multi-resolution and multi-source is one of the fundamental problems of GIS-T development. A spatial-temporal data model for GIS-T is proposed based on Spatial-temporal- Object Model. Transportation network data is systemically managed using dynamic segmentation technologies. And then a spatial-temporal database is built to integrally store geographical data of multi-time for transportation. Based on the spatial-temporal database, functions of spatial analysis of GIS-T are substantively extended. Fractal module is developed to improve the analyzing in intensity, density, structure and connectivity of transportation network based on the validation and evaluation of topologic relation. Integrated fractal with GIS-T strengthens the functions of spatial analysis and enriches the approaches of data mining and knowledge discovery of transportation network. Finally, the feasibility of the model and methods are tested thorough Guangdong Geographical Information Platform for Highway Project.

Research on Some Bus Transport Networks with Random Overlapping Clique Structure

International Nuclear Information System (INIS)

Yang Xuhua; Sun Youxian; Wang Bo; Wang Wanliang

2008-01-01

On the basis of investigating the statistical data of bus transport networks of three big cities in China, we propose that each bus route is a clique (maximal complete subgraph) and a bus transport network (BTN) consists of a lot of cliques, which intensively connect and overlap with each other. We study the network properties, which include the degree distribution, multiple edges' overlapping time distribution, distribution of the overlap size between any two overlapping cliques, distribution of the number of cliques that a node belongs to. Naturally, the cliques also constitute a network, with the overlapping nodes being their multiple links. We also research its network properties such as degree distribution, clustering, average path length, and so on. We propose that a BTN has the properties of random clique increment and random overlapping clique, at the same time, a BTN is a small-world network with highly clique-clustered and highly clique-overlapped. Finally, we introduce a BTN evolution model, whose simulation results agree well with the statistical laws that emerge in real BTNs

Smart Collision Avoidance and Hazard Routing Mechanism for Intelligent Transport Network

Science.gov (United States)

Singh, Gurpreet; Gupta, Pooja; Wahab, Mohd Helmy Abd

2017-08-01

The smart vehicular ad-hoc network is the network that consists of vehicles for smooth movement and better management of the vehicular connectivity across the given network. This research paper aims to propose a set of solution for the VANETs consisting of the automatic driven vehicles, also called as the autonomous car. Such vehicular networks are always prone to collision due to the natural or un-natural reasons which must be solved before the large-scale deployment of the autonomous transport systems. The newly designed intelligent transport movement control mechanism is based upon the intelligent data propagation along with the vehicle collision and traffic jam prevention schema [8], which may help the future designs of smart cities to become more robust and less error-prone. In the proposed model, the focus is on designing a new dynamic and robust hazard routing protocol for intelligent vehicular networks for improvement of the overall performance in various aspects. It is expected to improve the overall transmission delay as well as the number of collisions or adversaries across the vehicular network zone.

Behavioural Models for Route Choice of Passengers in Multimodal Public Transport Networks

DEFF Research Database (Denmark)

Anderson, Marie Karen

in the estimation of route choice models of public transport users based upon observed choices. Public transport route choice models have not benefitted from the same technological enhancements as car models because of the necessity (i) to collect additional information concerning lines and transfers, and (ii...... modes, public transport modes, lines, transfers, egress modes) is large. This thesis proposes a doubly stochastic approach for generating alternative routes that are relevant to travellers, since the method allows accounting for both perceived costs of the network elements and heterogeneity......The subject of this thesis is behavioural models for route choice of passengers in multimodal public transport networks. While research in sustainable transport has dedicated much attention toward the determinants of choice between car and sustainable travel options, it has devoted less attention...

Complexity analysis on public transport networks of 97 large- and medium-sized cities in China

Science.gov (United States)

Tian, Zhanwei; Zhang, Zhuo; Wang, Hongfei; Ma, Li

2018-04-01

The traffic situation in Chinese urban areas is continuing to deteriorate. To make a better planning and designing of the public transport system, it is necessary to make profound research on the structure of urban public transport networks (PTNs). We investigate 97 large- and medium-sized cities’ PTNs in China, construct three types of network models — bus stop network, bus transit network and bus line network, then analyze the structural characteristics of them. It is revealed that bus stop network is small-world and scale-free, bus transit network and bus line network are both small-world. Betweenness centrality of each city’s PTN shows similar distribution pattern, although these networks’ size is various. When classifying cities according to the characteristics of PTNs or economic development level, the results are similar. It means that the development of cities’ economy and transport network has a strong correlation, PTN expands in a certain model with the development of economy.

Lattice Boltzmann simulation of CO2 reactive transport in network fractured media

Science.gov (United States)

Tian, Zhiwei; Wang, Junye

2017-08-01

Carbon dioxide (CO2) geological sequestration plays an important role in mitigating CO2 emissions for climate change. Understanding interactions of the injected CO2 with network fractures and hydrocarbons is key for optimizing and controlling CO2 geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO2 reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO2 geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity.

Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal; Caracterisation des proprietes des argiles d'Opalinus (roche d'accueil potentielle pour un stockage de dechets radioactifs) relatives au transport des gaz

Energy Technology Data Exchange (ETDEWEB)

Marschall, P. [Nagra - National Cooperative for the Disposal of Radioactive Waste, Wettingen (Switzerland); Horseman, S. [British Geological Survey, Kingsley Dunham Centre, Keyworth (United Kingdom); Gimmi, T. [Bern Univ. (Switzerland); Paul Scherrer Inst. (PSI), Villigen (Switzerland)

2005-07-01

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10{sup -20} to 10{sup -21} m{sup 2} and a moderate anisotropy ratio {<=} 10. Porosity depends on clay content and burial depth; values of {approx} 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

Pore-Network Modeling of Water and Vapor Transport in the Micro Porous Layer and Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

NARCIS (Netherlands)

Qin, C.; Hassanizadeh, S.M.; van Oosterhout, L.M.

2016-01-01

In the cathode side of a polymer electrolyte fuel cell (PEFC), a micro porous layer (MPL) added between the catalyst layer (CL) and the gas diffusion layer (GDL) plays an important role in water management. In this work, by using both quasi-static and dynamic pore-network models, water and vapor

Transport of Gas Phase Radionuclides in a Fractured, Low-Permeability Reservoir

Science.gov (United States)

Cooper, C. A.; Chapman, J.

2001-12-01

The U.S. Atomic Energy Commission (predecessor to the Department of Energy, DOE) oversaw a joint program between industry and government in the 1960s and 1970s to develop technology to enhance production from low-permeability gas reservoirs using nuclear stimulation rather than conventional means (e.g., hydraulic and/or acid fracturing). Project Rio Blanco, located in the Piceance Basin, Colorado, was the third experiment under the program. Three 30-kiloton nuclear explosives were placed in a 2134 m deep well at 1780, 1899, and 2039 m below the land surface and detonated in May 1973. Although the reservoir was extensively fractured, complications such as radionuclide contamination of the gas prevented production and subsequent development of the technology. Two-dimensional numerical simulations were conducted to identify the main transport processes that have occurred and are currently occurring in relation to the detonations, and to estimate the extent of contamination in the reservoir. Minor modifications were made to TOUGH2, the multiphase, multicomponent reservoir simulator developed at Lawrence Berkeley National Laboratories. The simulator allows the explicit incorporation of fractures, as well as heat transport, phase change, and first order radionuclide decay. For a fractured two-phase (liquid and gas) reservoir, the largest velocities are of gases through the fractures. In the gas phase, tritium and one isotope of krypton are the principle radionuclides of concern. However, in addition to existing as a fast pathway, fractures also permit matrix diffusion as a retardation mechanism. Another retardation mechanism is radionuclide decay. Simulations show that incorporation of fractures can significantly alter transport rates, and that radionuclides in the gas phase can preferentially migrate upward due to the downward gravity drainage of liquid water in the pores. This project was funded by the National Nuclear Security Administration, Nevada Operations Office

Long-term transport network 2008-2017 investment forecast plan; Plan previsionnel d'investissements a long terme 2008-2017 sur le reseau de transport

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01