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Sample records for authority compressed natural

  1. Future perspective for CNG (Compressed Natural Gas)

    International Nuclear Information System (INIS)

    Veen, D.

    1999-01-01

    Driving on natural gas (CNG, Compressed Natural Gas) has been the talk of the industry for many years now. Although the benefits of natural gas as an engine fuel have become well-known, this phenomenon does not seem to gain momentum in the Netherlands. Over the last few months, however, the attitude towards CNG seems to be changing. Energy companies are increasingly engaged in commercial activities, e.g. selling natural gas at petrol stations, an increasing number of car manufacturers are delivering natural gas vehicles ex-works, and recently the NGV (Natural Gas Vehicles) Holland platform was set up for the unequivocal marketing of natural gas as an engine fuel

  2. Costs Associated With Compressed Natural Gas Vehicle Fueling Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.; Gonzales, J.

    2014-09-01

    This document is designed to help fleets understand the cost factors associated with fueling infrastructure for compressed natural gas (CNG) vehicles. It provides estimated cost ranges for various sizes and types of CNG fueling stations and an overview of factors that contribute to the total cost of an installed station. The information presented is based on input from professionals in the natural gas industry who design, sell equipment for, and/or own and operate CNG stations.

  3. Compressed natural gas vehicles motoring towards a green Beijing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Kraft-Oliver, T. [International Institute for Energy Conservation (IIEC) - Asia, Bangkok (Thailand); Guo Xiao Yan [China North Vehicle Research Institute (CNVRI), Beijing (China)

    1996-12-31

    This paper first describes the state-of-the-art of compressed natural gas (CNG) technologies and evaluates the market prospects for CNG vehicles in Beijing. An analysis of the natural gas resource supply for fleet vehicles follows. The costs and benefits of establishing natural gas filling stations and promoting the development of vehicle technology are evaluated. The quantity of GHG reduction is calculated. The objective of the paper is to provide information of transfer niche of CNG vehicle and equipment production in Beijing. This paper argues that the development of CNG vehicles is a cost-effective strategy for mitigating both air pollution and GHG.

  4. Compressed Natural Gas Technology for Alternative Fuel Power Plants

    Science.gov (United States)

    Pujotomo, Isworo

    2018-02-01

    Gas has great potential to be converted into electrical energy. Indonesia has natural gas reserves up to 50 years in the future, but the optimization of the gas to be converted into electricity is low and unable to compete with coal. Gas is converted into electricity has low electrical efficiency (25%), and the raw materials are more expensive than coal. Steam from a lot of wasted gas turbine, thus the need for utilizing exhaust gas results from gas turbine units. Combined cycle technology (Gas and Steam Power Plant) be a solution to improve the efficiency of electricity. Among other Thermal Units, Steam Power Plant (Combined Cycle Power Plant) has a high electrical efficiency (45%). Weakness of the current Gas and Steam Power Plant peak burden still using fuel oil. Compressed Natural Gas (CNG) Technology may be used to accommodate the gas with little land use. CNG gas stored in the circumstances of great pressure up to 250 bar, in contrast to gas directly converted into electricity in a power plant only 27 bar pressure. Stored in CNG gas used as a fuel to replace load bearing peak. Lawyer System on CNG conversion as well as the power plant is generally only used compressed gas with greater pressure and a bit of land.

  5. Compressed Natural Gas Technology for Alternative Fuel Power Plants

    Directory of Open Access Journals (Sweden)

    Pujotomo Isworo

    2018-01-01

    Full Text Available Gas has great potential to be converted into electrical energy. Indonesia has natural gas reserves up to 50 years in the future, but the optimization of the gas to be converted into electricity is low and unable to compete with coal. Gas is converted into electricity has low electrical efficiency (25%, and the raw materials are more expensive than coal. Steam from a lot of wasted gas turbine, thus the need for utilizing exhaust gas results from gas turbine units. Combined cycle technology (Gas and Steam Power Plant be a solution to improve the efficiency of electricity. Among other Thermal Units, Steam Power Plant (Combined Cycle Power Plant has a high electrical efficiency (45%. Weakness of the current Gas and Steam Power Plant peak burden still using fuel oil. Compressed Natural Gas (CNG Technology may be used to accommodate the gas with little land use. CNG gas stored in the circumstances of great pressure up to 250 bar, in contrast to gas directly converted into electricity in a power plant only 27 bar pressure. Stored in CNG gas used as a fuel to replace load bearing peak. Lawyer System on CNG conversion as well as the power plant is generally only used compressed gas with greater pressure and a bit of land.

  6. Compressed natural gas fueled vehicles: The Houston experience

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    The report describes the experience of the City of Houston in defining the compressed natural gas fueled vehicle research scope and issues. It details the ways in which the project met initial expectations, and how the project scope, focus, and duration were adjusted in response to unanticipated results. It provides examples of real world successes and failures in efforts to commercialize basic research in adapting a proven technology (natural gas) to a noncommercially proven application (vehicles). Phase one of the demonstration study investigates, develops, documents, and disseminates information regarding the economic, operational, and environmental implications of utilizing compressed natural gas (CNG) in various truck fueling applications. The four (4) truck classes investigated are light duty gasoline trucks, medium duty gasoline trucks, medium duty diesel trucks and heavy duty diesel trucks. The project researches aftermarket CNG conversions for the first three vehicle classes and original equipment manufactured (OEM) CNG vehicles for light duty gasoline and heavy duty diesel classes. In phase two of the demonstration project, critical issues are identified and assessed with respect to implementing use of CNG fueled vehicles in a large vehicle fleet. These issues include defining changes in local, state, and industry CNG fueled vehicle related codes and standards; addressing vehicle fuel storage limitations; using standardized vehicle emission testing procedures and results; and resolving CNG refueling infrastructure implementation issues and related cost factors. The report identifies which CNG vehicle fueling options were tried and failed and which were tried and succeeded, with and without modifications. The conclusions include a caution regarding overly optimistic assessments of CNG vehicle technology at the initiation of the project.

  7. CNG (compressed natural gas) as fuel for the transport sector in Trinidad and Tobago

    Energy Technology Data Exchange (ETDEWEB)

    So`Brien, G.C.; Persad, P.; Satcunanathan, S. [University of the West Indies, St. Augustine (Trinidad)

    1996-08-01

    Several studies have established that Trinidad and Tobago is well positioned to consider the substitution of compressed natural gas (CNG) for gasoline or diesel in the transport sector. Consequently a programme of conversion of private motors was initiated. Despite considerable advertisement programs projecting CNG as an environmentally friendly and cheap fuel, there is not yet widespread acceptance of the technology. The reasons for this are analysed. It is recommended that the policy of CNG usage be reviewed and the emphasis be shifted to transport fleets. It is also recommended that tax credits be considered as an incentive to users. (author)

  8. Removal of methane from compressed natural gas fueled vehicle exhaust

    International Nuclear Information System (INIS)

    Subramanian, S.; Kudla, R.J.; Chattha, M.S.

    1992-01-01

    The objective of this paper is to investigate the modes of methane (CH 4 ) removal from simulated compressed natural gas (CNG) fueled vehicle exhaust under net oxidizing, net reducing, and stoichiometric conditions. Model reaction studies were conducted. The results suggest that the oxidation of methane with oxygen contributes to the removal of methane under net oxidizing conditions. In contrast, the oxidation of methane with oxygen as well as nitric oxide contributes to its removal under net reducing conditions. The steam reforming reaction does not significantly contribute to the removal of methane. The methane conversions under net reducing conditions are higher than those observed under net oxidizing conditions. The study shows that the presence of carbon monoxide in the feed gas leads to a gradual decrease in the methane conversion with increasing redox ratio, under net oxidizing conditions. a minimum in methane conversion is observed at a redox ratio of 0. 8. The higher activity for the methane-oxygen reaction resulting from a lowering in the overall oxidation state of palladium and the contribution of the methane-nitric oxide reaction toward the removal of CH 4 appear to account for the higher CH 4 conversions observed under net reducing conditions

  9. Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Kay L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ramsden, Margo M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gonzales, John E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lynch, Lauren [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coale, Bob [Gladstein, Neandross & Associates, Santa Monica, CA (United States); Kohout, Jarrod [Gladstein, Neandross & Associates, Santa Monica, CA (United States)

    2017-09-28

    To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignition of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible

  10. The use of compressed natural gas as a strategy of development of natural gas industry; Utilizacao do GNC (Gas Natural Comprimido) como estrategia de desenvolvimento da industria do gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Bock, Jucemara [Companhia de Gas do Estado do Rio Grande do Sul (Sulgas), Porto Alegre, RS (Brazil). Coordenacao de Segmento Veicular; Rickmann, Cristiano [Companhia de Gas do Estado do Rio Grande do Sul (Sulgas), Porto Alegre, RS (Brazil). Gerencia de Novos Negocios; Maestri, Juares [Companhia de Gas do Estado do Rio Grande do Sul (Sulgas), Porto Alegre, RS (Brazil). Gerencia de Mercado de Grandes Consumidores

    2008-07-01

    This work emphasizes the Compressed Natural Gas (CNG) as modal of transport, used by the Company of Gas of the State of Rio Grande do Sul - Sulgas, through experience in pioneering project in Brazil: the introduction of the technology of Compressed Natural Gas (CNG) to assist areas where there is not the infrastructure of pipeline for the transport. The article offers a display of the project of expansion of the Natural gas in Rio Grande do Sul, through the supply of CNG to the company Tramontina in Carlos Barbosa's city in the year of 2002. The last aspect focused by this article demonstrates as the use of this transport technology impelled the development of the transport market in the State and it has been used as an important strategy for the development of the market of Natural Gas Vehicle (NGV) in the state. (author)

  11. On the phase transition nature in compressible Ising models

    International Nuclear Information System (INIS)

    Ota, A.T.

    1985-01-01

    The phase transition phenomenon is analysed in a compressible ferromagnetic Ising model at null field, through the mean-field approximation. The model studied is d-dimensional under the magnetic point of view and one-dimensional under the elastic point of view. This is achieved keeping the compressive interactions among the ions and rejecting annealing forces completely. The exchange parameter J is linear and the elastic potential quadratic in relation to the microscopic shifts of the lattice. In the one-dimensional case, this model shows no phase transition. In the two-dimensional case, the role of the S i spin of the i-the ion is crucial: a) for spin 1/2 the transitions are of second order; b) for spin 1, desides the second order transitions there is a three-critical point and a first-order transitions line. (L.C.) [pt

  12. Compressed natural gas for vehicles and how we can develop and meet the market

    International Nuclear Information System (INIS)

    Pinkerton, W.E.

    1992-01-01

    This paper reports that state and federal legislation have mandated the use of clean burning fuels. Clean fuels include: compressed natural gas (CNG), ethanol, methanol, liquefied petroleum gas (LPG), electricity, and reformulated gasoline. The Clean Air Amendments 1990 have created support for the rapid utilization of the compressed natural gas (CNG). Responsively, diverse occupations related to this industry are emerging. A coordinated infrastructure is vital to the successful promotion of clean fuels and synchronized endorsement of the law

  13. The increase of compressive strength of natural polymer modified concrete with Moringa oleifera

    Science.gov (United States)

    Susilorini, Rr. M. I. Retno; Santosa, Budi; Rejeki, V. G. Sri; Riangsari, M. F. Devita; Hananta, Yan's. Dianaga

    2017-03-01

    Polymer modified concrete is one of some concrete technology innovations to meet the need of strong and durable concrete. Previous research found that Moringa oleifera can be applied as natural polymer modifiers into mortars. Natural polymer modified mortar using Moringa oleifera is proven to increase their compressive strength significantly. In this resesearch, Moringa oleifera seeds have been grinded and added into concrete mix for natural polymer modified concrete, based on the optimum composition of previous research. The research investigated the increase of compressive strength of polymer modified concrete with Moringa oleifera as natural polymer modifiers. There were 3 compositions of natural polymer modified concrete with Moringa oleifera referred to previous research optimum compositions. Several cylinder of 10 cm x 20 cm specimens were produced and tested for compressive strength at age 7, 14, and, 28 days. The research meets conclusions: (1) Natural polymer modified concrete with Moringa oleifera, with and without skin, has higher compressive strength compared to natural polymer modified mortar with Moringa oleifera and also control specimens; (2) Natural polymer modified concrete with Moringa oleifera without skin is achieved by specimens contains Moringa oleifera that is 0.2% of cement weight; and (3) The compressive strength increase of natural polymer modified concrete with Moringa oleifera without skin is about 168.11-221.29% compared to control specimens

  14. Natural Gas Compression Technician: Apprenticeship Course Outline. Apprenticeship and Industry Training. 5311.1

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2011

    2011-01-01

    The graduate of the Natural Gas Compression Technician apprenticeship program is a certified journeyperson who will be able to install, commission, maintain and repair equipment used to gather store and transmit natural gas. Advanced Education and Technology has prepared this course outline in partnership with the Natural Gas Compression…

  15. Comparison of the biomechanical tensile and compressive properties of decellularised and natural porcine meniscus.

    Science.gov (United States)

    Abdelgaied, A; Stanley, M; Galfe, M; Berry, H; Ingham, E; Fisher, J

    2015-06-01

    Meniscal repair is widely used as a treatment for meniscus injury. However, where meniscal damage has progressed such that repair is not possible, approaches for partial meniscus replacement are now being developed which have the potential to restore the functional role of the meniscus, in stabilising the knee joint, absorbing and distributing stress during loading, and prevent early degenerative joint disease. One attractive potential solution to the current lack of meniscal replacements is the use of decellularised natural biological scaffolds, derived from xenogeneic tissues, which are produced by treating the native tissue to remove the immunogenic cells. The current study investigated the effect of decellularisation on the biomechanical tensile and compressive (indentation and unconfined) properties of the porcine medial meniscus through an experimental-computational approach. The results showed that decellularised medial porcine meniscus maintained the tensile biomechanical properties of the native meniscus, but had lower tensile initial elastic modulus. In compression, decellularised medial porcine meniscus generally showed lower elastic modulus and higher permeability compared to that of the native meniscus. These changes in the biomechanical properties, which ranged from less than 1% to 40%, may be due to the reduction of glycosaminoglycans (GAG) content during the decellularisation process. The predicted biomechanical properties for the decellularised medial porcine meniscus were within the reported range for the human meniscus, making it an appropriate biological scaffold for consideration as a partial meniscus replacement. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn

    2004-03-01

    This report documents work performed in Phase I of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report describes a number of potential enhancements to the existing natural gas compression infrastructure that have been identified and qualitatively demonstrated in tests on three different integral engine/compressors in natural gas transmission service.

  17. Life cycle greenhouse emissions of compressed natural gas-hydrogen mixtures for transportation in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, P. [Instituto de Energia y Desarrollo Sustentable, CNEA, CONICET, Av. del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina); Dawidowski, L.; Gomez, D. [Gerencia Quimica, CNEA, Av. Gral. Paz 1499, San Martin (Argentina); Pasquevich, D. [Instituto de Energia y Desarrollo Sustentable, CNEA, CONICET, Av. del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina); Centro Atomico Bariloche, CNEA, Av. Bustillo 9500, S.C. de Bariloche (Argentina)

    2010-06-15

    We have developed a model to assess the life cycle greenhouse emissions of compressed natural gas-hydrogen (CNG-H{sub 2}) mixtures used for transportation in Argentina. The overall fuel life cycle is assessed through a well-to-wheel (WTW) analysis for different hydrogen generation and distribution options. The combustion stage in road vehicles is modeled using the COPERT IV model. Hydrogen generation options include classical steam methane reforming (SMR) and water electrolysis (WE) in central plants and distributed facilities at the refueling stations. Centralized hydrogen generation by electrolysis in nuclear plants as well as the use of solar photovoltaic and wind electricity is also considered. Hydrogen distribution options include gas pipeline and refrigerated truck transportation for liquefied hydrogen. A total number of fifteen fuel pathways are studied; in all the cases the natural gas-hydrogen mixture is made at the refueling station. The use of WE using nuclear or wind electricity appears to be less contaminant that the use of pure CNG. (author)

  18. Tensile and compressive failure of 3D printed and natural sandstones

    Science.gov (United States)

    Vogler, D.; Perras, M.; Walsh, S. D. C.; Dombrovski, E.

    2016-12-01

    Artificial 3D-printed sandstone samples have the potential to replicate the physical characteristics of natural sandstones, allowing the creation of reproducible rock specimens. If successful, such materials could be used to replicate heterogeneous specimens for destructive testing in a number of different configurations and across different test types. In this study, we consider to what degree such artificial samples can match the tensile and compressive failure behavior of natural sandstones. Specifically, 3D printed sandstone samples were subjected to both indirect Brazilian and unconfined compression tests. Two different types of 3D printed and three natural sandstones were tested, comparing their 1) tensile and compressive strength; 2) strain path to failure; 3) failure mode; and 4) fracture geometry after failure. The artificial sandstone samples demonstrated tensile strengths and failure modes similar to those exhibited in weak natural sandstones. Moreover, the ratio of tensile to compressive strength was found to be similar across all materials tested including the 3D printed materials. Finally, the small-scale fracture surface roughness is comparable between artificial and natural specimens of similar tensile strength - suggesting similar grain- and macro-scale failure behavior between the 3D printed and natural sandstone samples.

  19. Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, K.; Melendez, M.; Gonzales, J.; Lynch, L.; Boale, B.; Kohout, J.

    2017-09-28

    To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. This handbook covers the primary elements that must be considered when developing a CNG vehicle maintenance facility design that will protect against the ignition of natural gas releases. It also discusses specific protocols and training needed to ensure safety.

  20. 49 CFR 571.304 - Standard No. 304; Compressed natural gas fuel container integrity.

    Science.gov (United States)

    2010-10-01

    ....4.1. Liner means the inner gas tight container or gas cylinder to which the overwrap is applied... statement: “If there is a question about the proper use, installation, or maintenance of this container... 49 Transportation 6 2010-10-01 2010-10-01 false Standard No. 304; Compressed natural gas fuel...

  1. Cow Power: A Case Study of Renewable Compressed Natural Gas as a Transportation Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Mintz, Marianne [Argonne National Lab. (ANL), Argonne, IL (United States); Tomich, Matthew [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-01

    This case study explores the production and use of renewable compressed natural gas (R-CNG)—derived from the anaerobic digestion (AD) of dairy manure—to fuel 42 heavy-duty milk tanker trucks operating in Indiana, Michigan, Tennessee, and Kentucky.

  2. Potentiality of the Usage of Compressed Natural Gas for Competitiveness in Service Delivery Industries

    Directory of Open Access Journals (Sweden)

    Gazi Mohammad Hasan Jamil

    2014-08-01

    Full Text Available Abstract. With the rising costs of gasoline, many vehicle owners are looking for alternatives of it. Compressed natural gas (CNG has been tested for this very purpose in some countries and found as a better alternative so far. CNG comes from country’s natural resources and it is clean and less costly to use. This paper is mainly an analysis of the potential benefits of using natural gas as a transportation fuel by the service delivery industries. It will examine CNG’s potential contribution in reducing delivery and vehicle maintenance cost, saving money in the long run projects, improving fuel efficiency, enhancing physical safety and assuring environment friendly emissions of carbon monoxide or reactive gases for the service delivery industries.Keywords: Compressed natural gas (CNG, Service Delivery, Fossil fuel, Global warming, Competitiveness

  3. Building a Business Case for Compressed Natural Gas in Fleet Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, G.

    2015-03-19

    Natural gas is a clean-burning, abundant, and domestically produced source of energy. Compressed natural gas (CNG) has recently garnered interest as a transportation fuel because of these attributes and because of its cost savings and price stability compared to conventional petroleum fuels. The National Renewable Energy Laboratory (NREL) developed the Vehicle Infrastructure and Cash-Flow Evaluation (VICE) model to help businesses and fleets evaluate the financial soundness of CNG vehicle and CNG fueling infrastructure projects.

  4. Mechanical Properties of Injection Molded and Compression Molded Samples from Nature-Butadiene Rubber

    Directory of Open Access Journals (Sweden)

    Skrobak Adam

    2016-01-01

    Full Text Available The aim of this paper is to show what extent there is an impact on the mechanical properties (tensile strength and tear strength of a standardized testing sample made of rubber compound based on nature rubber and butadiene rubber produced by injection molding in comparison with a sample produced by classic preparation (cutting out a compression molded plate according to the standard ISO 23529. For realization of this study it was necessary to design and produce an injection mold for all types testing samples. Subsequently, mechanical properties such as the tensile stress-strain and tear strenght of compression molded samples and injection molded samples were studied, compared and discussed.

  5. Modified Liu-Carter Compression Model for Natural Clays with Various Initial Water Contents

    Directory of Open Access Journals (Sweden)

    Sen Qian

    2016-01-01

    Full Text Available The initial water content has a significant effect on the compression behaviour of reconstituted clays. This effect has to be considered in the Liu-Carter model to ensure the addition voids ratio only related to soil structure. A modified Liu-Carter compression model is proposed by introducing the empirical equations for reconstituted clays at different initial water contents into the Liu-Carter model. The proposed model is verified against the experimental results from the literature. The simulations by the proposed method are also compared with that by old method where the influence of initial water content is not considered. The results show that the predicted virgin compression curves of natural clays are similar, but the values of b and Δey may be very different.

  6. 78 FR 21349 - Orders Granting Authority To Import and Export Natural Gas, To Export Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-10

    ... 13-03-NG ProGas USA Inc........ Order granting blanket authority to import/export natural gas from/to... DEPARTMENT OF ENERGY Orders Granting Authority To Import and Export Natural Gas, To Export... authority to import and export natural gas and liquefied natural gas and vacating prior authority. These...

  7. On the Use of Vibro-Compressed Units with Bio-Natural Aggregate

    Directory of Open Access Journals (Sweden)

    Mauro Sassu

    2016-09-01

    Full Text Available The paper deals with the use of vibro-compressed units with bio-natural components on construction. The proposed mix design of vibrated blocks consist of cork granules and/or hemp shives, with the aim to substitute polymeric elements or expanded clay, together with the use of natural hydraulic lime (NHL as binder. An experimental campaign is presented, with mechanical tests to evaluate the influence of each component on flexural and compression behavior. The proposal is also investigated from a productive point of view, considering how it can be harmonized in the productive process of lightweight aggregate concrete units without modifications in the productive process. The tested elements could perform a certain reduction of the carbon impact, maintaining interesting mechanical properties. The application of the proposed units in several contexts, as separating elements joined with structural components, is considered to improve rehabilitation or to obtain higher performances in buildings.

  8. Mechanical Resistance to Compression Poured Earth, Mixed With Natural Latex Obtained From Tabernaemontanaalba Mill Apocynaceae.

    OpenAIRE

    Erick. Zarazua-Portes; Carlos Zuñiga-Leal; Rocio Rafaela Gallegos-Villela; Yolanda G. Aranda-Jiménez

    2016-01-01

    Pouredearthis presented as an environmentally friendly alternative for building. This technique uses hearth components and stabilizers, plus some natural additives or chemicals that can alter mechanical strength characteristics.Current studies show that concrete has higher value in terms of compressive strength and durability according to dosages of these components, but it is necessary to analyze other stabilizers that reduce building cost. In this study, samples of soil denominated Champayá...

  9. Alternative Fuel Vehicles: The Case of Compressed Natural Gas (CNG) Vehicles in California Households

    OpenAIRE

    Abbanat, Brian A.

    2001-01-01

    Compressed natural gas (CNG) vehicles have been used internationally by fleets and households for decades. The use of CNG vehicles results in less petroleum consumption, and fewer air pollutant and greenhouse gas emissions in most applications. In the United States, the adoption of CNG technology has been slowed by the availability of affordable gasoline and diesel fuel. This study addresses the potential market for CNG vehicles at the consumer level in California. Based on semi-structured pe...

  10. Survey for the development of compressed natural gas systems (CNG) for vehicles

    OpenAIRE

    Abulamosha, A.M.

    2005-01-01

    Compressed Natural Gas (CNG) vehicles have been used internationally by fleets for decades. The use of CNG vehicles results in less petroleum consumption, resulting in fewer air pollutants and greenhouse gas emissions in most applications. In Europe, the adoption of CNG among consumers has been slowed by the availability of affordable gasoline and diesel fuel. This investigation addresses the current situation of the CNG vehicle at the manufacturing level and the consumer level in Europe. Bas...

  11. Combustion Temperature Effect of Diesel Engine Convert to Compressed Natural Gas Engine

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    Effect of combustion temperature in the engine cylinder of diesel engine convert to Compressed Natural Gas (CNG) engine was presents in this study. The objective of this study was to investigate the engine cylinder combustion temperature effect of diesel engine convert to CNG engine on variation engine speed. Problem statement: The hypothesis was that the lower performance of CNG engine was caused by the effect of lower in engine cylinder temperature. Are the CNG engine is lower cylinder temp...

  12. 78 FR 21351 - Orders Granting Authority to Import and Export Natural Gas, To Import Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-10

    ... Commodities Order granting blanket LLC. authority to import/export natural gas from/to Canada/ Mexico, to... Generale Order granting blanket Energy Corp. authority to import/export natural gas from/to Canada/ Mexico... Granting Authority to Import and Export Natural Gas, To Import Liquefied Natural Gas, To Export Liquefied...

  13. 77 FR 19277 - Orders Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During...

    Science.gov (United States)

    2012-03-30

    ... Natural Gas Inc. Order granting blanket authority to import/export LNG from/to Canada/Mexico by truck... granting blanket authority to export natural gas to Canada/ Mexico. BILLING CODE 6450-01-P ... Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During February 2012 FE...

  14. Energy equivalence factor in gasoline to compressed vehicle natural gas substitution

    International Nuclear Information System (INIS)

    Agudelo Santamaria, John R; Amell Arrieta, Andres A

    1992-01-01

    In this paper, the authors show a model based in a vehicle energy balance used to obtain the ratio of energy equivalence of natural gas and petrol used as fuels in the vehicle. The model includes the engine, transmission and natural gas cylinders effects. The model has been applied to different colombian natural gases, it shows that Guajira natural gas has 14,5% lower ratio than Cusiana natural gas and 5,6% lower ratio than Apiay natural gas, these results shows a need in the study of colombian natural gases interchangeability

  15. Potential hazards of compressed air energy storage in depleted natural gas reservoirs.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Paul W.; Grubelich, Mark Charles; Bauer, Stephen J.

    2011-09-01

    This report is a preliminary assessment of the ignition and explosion potential in a depleted hydrocarbon reservoir from air cycling associated with compressed air energy storage (CAES) in geologic media. The study identifies issues associated with this phenomenon as well as possible mitigating measures that should be considered. Compressed air energy storage (CAES) in geologic media has been proposed to help supplement renewable energy sources (e.g., wind and solar) by providing a means to store energy when excess energy is available, and to provide an energy source during non-productive or low productivity renewable energy time periods. Presently, salt caverns represent the only proven underground storage used for CAES. Depleted natural gas reservoirs represent another potential underground storage vessel for CAES because they have demonstrated their container function and may have the requisite porosity and permeability; however reservoirs have yet to be demonstrated as a functional/operational storage media for compressed air. Specifically, air introduced into a depleted natural gas reservoir presents a situation where an ignition and explosion potential may exist. This report presents the results of an initial study identifying issues associated with this phenomena as well as possible mitigating measures that should be considered.

  16. Effect of the state of internal boundaries on granite fracture nature under quasi-static compression

    Science.gov (United States)

    Damaskinskaya, E. E.; Panteleev, I. A.; Kadomtsev, A. G.; Naimark, O. B.

    2017-05-01

    Based on an analysis of the spatial distribution of hypocenters of acoustic emission signal sources and an analysis of the energy distributions of acoustic emission signals, the effect of the liquid phase and a weak electric field on the spatiotemporal nature of granite sample fracture is studied. Experiments on uniaxial compression of granite samples of natural moisture showed that the damage accumulation process is twostage: disperse accumulation of damages is followed by localized accumulation of damages in the formed macrofracture nucleus region. In energy distributions of acoustic emission signals, this transition is accompanied by a change in the distribution shape from exponential to power-law. Granite water saturation qualitatively changes the damage accumulation nature: the process is delocalized until macrofracture with the exponential energy distribution of acoustic emission signals. An exposure to a weak electric field results in a selective change in the damage accumulation nature in the sample volume.

  17. [Bone and joint changes due to compressed air in divers and Caisson workers (author's transl)].

    Science.gov (United States)

    Poser, H; Gabriel-Jürgens, P

    1977-02-01

    The radiological and morphological changes of Caisson disease in the skeleton are well known. The findings of interest to radiologists are described. Because of its position, its was possible to review a large number of divers in Kiel; these have been under observation for years, and even decades. The development, manifestation and course of chronic skeletal changes due to compressed air are described to compressed air are described and, according to severity, are classified into types 1 to 4. Late changes are discussed in detail, since these are of importance in relation to compensation.

  18. Recognition of time-compressed speech does not predict recognition of natural fast-rate speech by older listeners.

    Science.gov (United States)

    Gordon-Salant, Sandra; Zion, Danielle J; Espy-Wilson, Carol

    2014-10-01

    This study investigated whether recognition of time-compressed speech predicts recognition of natural fast-rate speech, and whether this relationship is influenced by listener age. High and low context sentences were presented to younger and older normal-hearing adults at a normal speech rate, naturally fast speech rate, and fast rate implemented by time compressing the normal-rate sentences. Recognition of time-compressed sentences over-estimated recognition of natural fast sentences for both groups, especially for older listeners. The findings suggest that older listeners are at a much greater disadvantage when listening to natural fast speech than would be predicted by recognition performance for time-compressed speech.

  19. Clean air program : design guidelines for bus transit systems using compressed natural gas as an alternative fuel

    Science.gov (United States)

    1996-06-01

    This report documents design guidelines for the safe use of Compressed Natural Gas (CNG). The report is designed to provide guidance, information on safe industry practices, applicable national codes and standards, and reference data that transit age...

  20. 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.

  1. Dynamic Compressive Strength and Failure of Natural Lake Ice Under Moderate Strain Rates at Near Melting Point Temperature

    Directory of Open Access Journals (Sweden)

    Chunfeng Qi

    Full Text Available Abstract This paper presents a series of uniaxial compressive experiments on natural lake ice under moderate strain-rate in the range of 10−1 to 102 s−1 at −0.1 °C. Natural lake ice samples of 8 cm by 8 cm in cross section and 20 cm high were used to investigate strain-rate dependence of uniaxial compressive strength and flaw effects on ice strength under moderate strain rates. The fracture modes of ice at moderate strain rates were also systematically investigated by using high-speed camera. It is found uniaxial compressive strength of natural lake ice increases with increasing strain-rate in the employed moderate strain-rate range. And natural flaws such as air bubble have a significant effect on uniaxial compressive strength of ice under moderate strain-rate, higher air content ice possesses lower compressive strength. Ice fracture mode depends on strain-rate (or compressive velocity of ice specimen, varying from splitting at strain rates lower than 10 s−1 to crushing at strain rates higher than 10 s−1. Ice specimen crushes into fine fragments may due to insufficient time for micro cracks to propagate, thus results in higher strength. In addition, dependence of compressive strength on strain-rate in a wide strain-rate range is also discussed.

  2. Experimental study of tensile strength of pharmaceutical tablets: effect of the diluent nature and compression pressure

    Science.gov (United States)

    Juban, Audrey; Briançon, Stéphanie; Puel, François; Hoc, Thierry; Nouguier-Lehon, Cécile

    2017-06-01

    In the pharmaceutical field, tablets are the most common dosage form for oral administration in the world. Among different manufacturing processes, direct compression is widely used because of its economics interest and it is a process which avoids the steps of wet granulation and drying processes. Tablets are composed of at least two ingredients: an active pharmaceutical ingredient (API) which is mixed with a diluent. The nature of the powders and the processing conditions are crucial for the properties of the blend and, consequently, strongly influence the mechanical characteristics of tablets. Moreover, tablets have to present a suitable mechanical strength to avoid crumbling or breaking when handling, while ensuring an appropriate disintegration after administration. Accordingly, this mechanical property is an essential parameter to consider. Experimental results showed that proportion of the diluent, fragmentary (DCPA) or plastic (MCC), had a large influence on the tensile strength evolution with API content as well as the compression load applied during tableting process. From these results a model was developed in order to predict the tensile strength of binary tablets by knowing the compression pressure. The validity of this model was demonstrated for the two studied systems and a comparison was made with two existing models.

  3. Experimental study of tensile strength of pharmaceutical tablets: effect of the diluent nature and compression pressure

    Directory of Open Access Journals (Sweden)

    Juban Audrey

    2017-01-01

    Full Text Available In the pharmaceutical field, tablets are the most common dosage form for oral administration in the world. Among different manufacturing processes, direct compression is widely used because of its economics interest and it is a process which avoids the steps of wet granulation and drying processes. Tablets are composed of at least two ingredients: an active pharmaceutical ingredient (API which is mixed with a diluent. The nature of the powders and the processing conditions are crucial for the properties of the blend and, consequently, strongly influence the mechanical characteristics of tablets. Moreover, tablets have to present a suitable mechanical strength to avoid crumbling or breaking when handling, while ensuring an appropriate disintegration after administration. Accordingly, this mechanical property is an essential parameter to consider. Experimental results showed that proportion of the diluent, fragmentary (DCPA or plastic (MCC, had a large influence on the tensile strength evolution with API content as well as the compression load applied during tableting process. From these results a model was developed in order to predict the tensile strength of binary tablets by knowing the compression pressure. The validity of this model was demonstrated for the two studied systems and a comparison was made with two existing models.

  4. Compressive Strength of Concrete made from Natural Fine Aggregate Sources in Minna, Nigeria

    Directory of Open Access Journals (Sweden)

    M. Abdullahi

    2017-12-01

    Full Text Available This work presented an investigation of concrete developed from five fine aggregate sources in Minna, Niger state, Nigeria. Tests conducted on the fine aggregate samples included specific gravity, sieve analysis, bulk density and moisture content. The concrete mix design was done using absolute volume method at various mix proportion of 1:2:4, 1:2:3 and 1:1:2 and water-cement ratios of 0.4, 0.45, 0.5, 0.55 and 0.6. The compressive strengths of concrete were determined at 28-day curing age. Test results revealed that the specific gravities of the aggregate were between 2.60 to 2.70, compacted bulk densities also ranged from 1505.18 to 1701.15kg/m3, loose bulk densities ranged from 1379.32 to 1478.17kg/m3, and moisture content ranged from 0.93 to 2.47%. All the fine aggregate samples satisfied the overall and medium grading limits for natural fine aggregates. The coarse aggregate used fairly followed the grading limit for aggregate size of 20 to 5 mm. The compressive strength of the concrete obtained using the aggregate samples A, B, C, D, and Eall within the ranges of 18.97 to 34.98 N/mm2. Statistical models were developed for the compressive strength of concrete as a function of water-cement ratio for various fine aggregate sources and mix proportions. The models were found to have good predictive the capabilities of the compressive strength of concrete for given water-cement ratio. The properties of fine aggregates and the resulting concrete characteristics showed that all the fine aggregate samples are suitable to be used for concrete production.

  5. 78 FR 46581 - Orders Granting Authority To Import and Export Natural Gas, and To Import Liquefied Natural Gas...

    Science.gov (United States)

    2013-08-01

    ... natural gas from/to Canada/Mexico. 3296 06/18/13 13-67-LNG ConocoPhillips Company..... Order granting... granting blanket authority to import/ export natural gas from/to Canada/Mexico, and to import LNG from... Granting Authority To Import and Export Natural Gas, and To Import Liquefied Natural Gas During June 2013...

  6. GPA/GPSA/OSU-Okmulgee natural gas compression technician training program

    Energy Technology Data Exchange (ETDEWEB)

    Doede, S.

    1999-07-01

    Approximately one year ago, OSU-Okmulgee and the Gas Processors Association began discussions about the possibility of developing a natural Gas Technician Training Program for GPA members. Following a presentation to the Membership and Services Committee, Chairman John Ehlers solicited and obtained the approval of the GPA Executive Committee to sponsor the program. Participation in the program was also made available to GPSA members. The purpose of the program is to upgrade the technical competency and professional level of incoming natural gas compression technicians. It educates students to analytically diagnose, service and maintain gas compression equipment and systems using industry recommended procedures, special tools and service information. It also provides course content, which will enable successful graduates to advance in position after additional experience, and to understand new systems, technologies and components as they are introduced. The two-year Associate-In-Applied Science Degree program includes six successive college semesters. Nearly one-half of the time is designated for technical/academic education at Oklahoma State University-Okmulgee with the balance of time allocated for on-the-job internship experiences at sponsoring GPA/GPSA members. Each block of technical education and general education course work is followed by an immediate work experience time period designated to reinforce the technical and general education. These time periods are approximately seven and one-half weeks in length each. It is essential for the success of the students and the program that the students' education at OSU-Okmulgee and work experiences at GPA/GPSA member facilities be closely aligned for maximum student learning and retention. In addition to technical classes on gas compression equipment and components, the courses offered in math, speech, technical writing, psychology and ethics for example, prepare students to be able to communicate well, get

  7. Boundary Domain Integral Method for Double Diffusive Natural Convection in Porous Media Saturated with Compressible Fluid

    Science.gov (United States)

    Kramer, J.; Jecl, R.; Škerget, L.

    2008-09-01

    In the present work, a Boundary Domain Integral Method, which has been already established for the solution of viscous incompressible fluid flow through porous media, is extended to capture compressible fluid flow in porous media. The presented numerical scheme was used for solving the problem of double diffusive natural convection in a square porous cavity heated from a side, while the horizontal walls are maintained at different concentrations. The Brinkman extension of Darcy equation is used to model the flow through porous medium. The velocity-vorticity formulation is employed enabeling the computation scheme to be partitioned into kinematic and kinetic parts. The results of double diffusive natural convection in porous cavity are presented in terms of velocity, temperature and concentration redistributions.

  8. 77 FR 31838 - Notice of Orders Granting Authority to Import and Export Natural Gas and Liquefied Natural Gas...

    Science.gov (United States)

    2012-05-30

    ... granting blanket Company. authority to import/ export natural gas from/ to Canada/Mexico, and to import LNG.... authority to import/ export natural gas from/ to Canada/Mexico, to export LNG to Canada/ Mexico by vessel... natural gas from/ to Canada/Mexico. 3095 04/30/12 12-39-NG Virginia Power Energy Order granting blanket...

  9. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2005-07-27

    This quarterly report documents work performed under Tasks 15, 16, and 18 through 23 of the project entitled: ''Technologies to Enhance the Operation of Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first documents a survey site test performed on a TCVC10 engine/compressor installed at Dominion's Groveport Compressor Station. This test completes planned screening efforts designed to guide selection of one or more units for design analysis and testing with emphasis on identification and reduction of compressor losses. The report further presents the validation of the simulation model for the Air Balance tasks and outline of conceptual manifold designs.

  10. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2005-10-27

    This quarterly report documents work performed under Tasks 15, 16, and 18 through 23 of the project entitled: ''Technologies to Enhance the Operation of Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first summarizes key results from survey site tests performed on an HBA-6 installed at Duke Energy's Bedford compressor station, and on a TCVC10 engine/compressor installed at Dominion's Groveport Compressor Station. The report then presents results of design analysis performed on the Bedford HBA-6 to develop options and guide decisions for reducing pulsations and enhancing compressor system efficiency and capacity. The report further presents progress on modifying and testing the laboratory GMVH6 at SwRI for correcting air imbalance.

  11. Developing compressed natural gas as an automotive fuel in Nigeria: Lessons from international markets

    International Nuclear Information System (INIS)

    Ogunlowo, Olufemi O.; Bristow, Abigail L.; Sohail, M.

    2015-01-01

    The Nigerian government proposed the use of compressed natural gas (CNG) as an automotive fuel in 1997 as part of the initiatives to harness natural gas (NG) resources but progress has been slow. This paper examines the natural gas vehicle (NGV) implementation approaches and outcomes in seven countries with diverse experiences in order to gain an understanding of the barriers to the NGV market development in Nigeria. The analysis employs hermeneutic principles to secondary data derived from academic literature, published reports from a variety of international agencies, grey literature, and text from online sources and identifies eight success factors for NGV market development namely: strategic intent, legal backing, learning and adaptation, assignment of responsibilities, financial incentives, NG pricing, consumer confidence, and NG infrastructure. The paper concludes that the principal impediment to NGV market development in Nigeria is the uncoordinated implementation approach and that greater government involvement is required in setting strategic goals, developing the legal and regulatory frameworks, setting of clear standards for vehicles and refuelling stations as well as assigning responsibilities to specific agencies. Short-term low cost policy interventions identified include widening the existing NG and gasoline price gap and offering limited support for refuelling and retrofitting facilities. - Highlights: • We examined the NGV policies and implementation strategies in selected countries. • The use of legislative mandates help deepen NGV penetration. • Aligning stakeholder interest is critical to NGV adoption. • Making national interest a priority ahead of regional infrastructure is a critical success factor. • Government support drives participation

  12. Dual-fuelling of a direct-injection automotive diesel engine by diesel and compressed natural gas

    International Nuclear Information System (INIS)

    Pirouzpanah, V.; Mohammadi Kosha, A.; Mosseibi, A.; Moshirabadi, J.; Gangi, A.; Moghadaspour, M.

    2000-01-01

    Application of Compressed Natural Gas in diesel engines has always been important, especially in the field of automotive engineering. This is due to easy accessibility, better mixing quality and good combustion characteristics of the Compressed Natural Gas fuel. In this study the application of Compressed Natural Gas fuel along with diesel oil in a heavy duty direct-injection automotive diesel engine is experimentally investigated. In order to convert a diesel engine into a diesel-gas one, the so called m ixed diesel-gas a pproach has been used and for this purpose a carbureted Compressed Natural Gas fuel system has been designed and manufactured. For controlling quantity of Compressed Natural Gas, the gas valve is linked to the diesel fuel injection system by means of a set of rods. Then, the dual-fuel system is adjusted so that, at full load conditions, the quantity of diesel fuel is reduced to 20% and 80% of its equivalent energy is substituted by Compressed Natural Gas fuel. Also injection pressure of pilot jet is increased by 11.4%. Performance and emission tests are conducted under variation of load and speed on both diesel and diesel-gas engines. Results show that, with equal power and torque, the diesel-gas engine has the potential to improve overall engine performance and emission. For example, at rated power and speed, fuel economy increases by 5.48%, the amount of smoke decreases by 78%, amount of CO decreases by 64.3% and mean exhaust gas temperature decreases by 6.4%

  13. Preliminary formation analysis for compressed air energy storage in depleted natural gas reservoirs :

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, William Payton

    2013-06-01

    The purpose of this study is to develop an engineering and operational understanding of CAES performance for a depleted natural gas reservoir by evaluation of relative permeability effects of air, water and natural gas in depleted natural gas reservoirs as a reservoir is initially depleted, an air bubble is created, and as air is initially cycled. The composition of produced gases will be evaluated as the three phase flow of methane, nitrogen and brine are modeled. The effects of a methane gas phase on the relative permeability of air in a formation are investigated and the composition of the produced fluid, which consists primarily of the amount of natural gas in the produced air are determined. Simulations of compressed air energy storage (CAES) in depleted natural gas reservoirs were carried out to assess the effect of formation permeability on the design of a simple CAES system. The injection of N2 (as a proxy to air), and the extraction of the resulting gas mixture in a depleted natural gas reservoir were modeled using the TOUGH2 reservoir simulator with the EOS7c equation of state. The optimal borehole spacing was determined as a function of the formation scale intrinsic permeability. Natural gas reservoir results are similar to those for an aquifer. Borehole spacing is dependent upon the intrinsic permeability of the formation. Higher permeability allows increased injection and extraction rates which is equivalent to more power per borehole for a given screen length. The number of boreholes per 100 MW for a given intrinsic permeability in a depleted natural gas reservoir is essentially identical to that determined for a simple aquifer of identical properties. During bubble formation methane is displaced and a sharp N2methane boundary is formed with an almost pure N2 gas phase in the bubble near the borehole. During cycling mixing of methane and air occurs along the boundary as the air bubble boundary moves. The extracted gas mixture changes as a

  14. Compressed natural gas as a vehicle to promote development of consumer market in Campina Grande - PB (Brazil); O gas natural comprimido como fomentador do desenvolvimento do mercado consumidor de gas natural na regiao de Campina Grande - PB

    Energy Technology Data Exchange (ETDEWEB)

    Bonfim, Marcelo dos Santos; Santos, Edmilson Moutinho dos [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Programa Interunidades de Pos-Graduacao em Energia (PIPGE)

    2004-07-01

    Investments required for natural gas distribution networks are high. The use of compressed natural gas (CNG) is seen as a way to prepare and develop consuming markets to receive those networks. This paper outlines the socio-economic context and the reasons that motivated the creation of a CNG project in Campina Grande, in the state of Paraiba. Technical aspects of project implementation are described, including difficulties encountered and courses of action undertaken as a result. Other aspects considered include the social and economic impact and local consumer's expectations with the arrival of new fuel. The study also considers factors relevant to the project such as the distance from the pressure measurement and regulation station, transported volumes, technology used, infrastructure and road conditions. (author)

  15. Subjecting Nature to Central Authority: The Struggle over Public ...

    African Journals Online (AJOL)

    sulaiman.adebowale

    2006-09-16

    Sep 16, 2006 ... preuves récoltées portent à croire que les plans de gestion collaborative ne comportent pas de ... under representative authority do not foster the formation of a citizenry. They simply become part of ...... UWA, 2000c, 'Revenue Sharing Programme around Protected Areas,' Strategic document, Kampala ...

  16. Co-Authoring: A Natural Form of Cooperative Learning.

    Science.gov (United States)

    Chapman, Ann D.; And Others

    1992-01-01

    Presents a method of improving student term papers that employs an approach requiring students to co-author a paper with other students in a group. Describes the four key elements of successful cooperative learning. Provides details about how this approach can be carried out. (HB)

  17. Investigating the Methane Footprint of Compressed Natural Gas Stations in the Los Angeles Basin

    Science.gov (United States)

    Carranza, V.; Hopkins, F. M.; Randerson, J. T.; Bush, S.; Ehleringer, J. R.; Miu, J.

    2013-12-01

    In recent years, natural gas has taken on a larger role in the United States' discourse on energy policy because it is seen as a fuel that can alleviate the country's dependence on foreign energy while simultaneously reducing greenhouse gas emissions. To this end, the State of California promotes the use of vehicles fueled by compressed natural gas (CNG). However, the implications of increased CNG vehicles for greenhouse gas emission reduction are not fully understood. Specifically, methane (CH4) leakages from natural gas infrastructure could make the switch from conventional to CNG vehicles a source of CH4 to the atmosphere, and negate the greenhouse-gas reduction benefit of this policy. The goal of our research is to provide an analysis of potential CH4 leakages from thirteen CNG filling stations in Orange County, California. To improve our understanding of CH4 leakages, we used a mobile laboratory, which is a Ford Transit van equipped with cavity-ring down Picarro spectrometers, to measure CH4 mixing ratios in these CNG stations. MATLAB and ArcGIS were used to conduct statistical analysis and to construct spatial and temporal maps for each transect. We observed mean levels of excess CH4 (relative to background CH4 mixing ratios) ranging from 60 to 1700 ppb at the CNG stations we sampled. Repeated sampling of CNG stations revealed higher levels of excess CH4 during the daytime compared to the nighttime. From our observations, CNG storage tanks and pumps have approximately the same CH4 leakage levels. By improving our understanding of the spatial and temporal patterns of CH4 emissions from CNG stations, our research can provide valuable information to reduce the climate footprint of the natural gas industry.

  18. 77 FR 12274 - Orders Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During...

    Science.gov (United States)

    2012-02-29

    ... BG LNG SERVICES, LLC 12-04-LNG MICHIGAN CONSOLIDATED GAS COMPANY 12-02-NG ENERGY SOURCE CANADA INC 12... Federal holidays. Issued in Washington, DC, on February 22, 2012. John A. Anderson, Manager, Natural Gas... granting blanket authority Natural Gas LLC. to import natural gas from Canada. 3057 01/10/12 12-03-NG...

  19. TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

    2005-01-01

    This quarterly report documents work performed under Tasks 10 through 14 of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first documents tests performed on a KVG103 engine/compressor installed at Duke's Thomaston Compressor Station. This is the first series of tests performed on a four-stroke engine under this program. Additionally, this report presents results, which complete a comparison of performance before and after modification to install High Pressure Fuel Injection and a Turbocharger on a GMW10 at Williams Station 60. Quarterly Reports 7 and 8 already presented detailed data from tests before and after this modification, but the final quantitative comparison required some further analysis, which is presented in Section 5 of this report. The report further presents results of detailed geometrical measurements and flow bench testing performed on the cylinders and manifolds of the Laboratory Cooper GMVH6 engine being employed for two-stroke engine air balance investigations. These measurements are required to enhance the detailed accuracy in modeling the dynamic interaction of air manifold, exhaust manifold, and in-cylinder fuel-air balance.

  20. Diesel vs. compressed natural gas for school buses: a cost-effectiveness evaluation of alternative fuels

    International Nuclear Information System (INIS)

    Cohen, J.T.

    2005-01-01

    Reducing emissions from school buses is a priority for both state and federal regulators. Two popular alternative technologies to conventional diesel (CD) are emission controlled diesel (ECD), defined here to be diesel buses equipped with continuously regenerating particle filters, and engines fueled by compressed natural gas (CNG). This paper uses a previously published model to quantify the impact of particulate matter (PM), oxides of nitrogen (NO x ), and sulfur dioxide (SO 2 ) emissions on population exposure to ozone and to primary and secondary PM, and to quantify the resulting health damages, expressed in terms of lost quality adjusted life years (QALYs). Resource costs include damages from greenhouse gas-induced climate change, vehicle procurement, infrastructure development, and operations. I find that ECD and CNG produce very similar reductions in health damages compared to CD, although CNG has a modest edge because it may have lower NO x emissions. However, ECD is far more cost effective ($400,000-900,000 cost per QALY saved) than CNG (around $4 million per QALY saved). The results are uncertain because the model used makes a series of simplifying assumptions and because emissions data and cost data for school buses are very limited

  1. Analisis Kekuatan Tangki CNG Ditinjau dengan Material Logam Lapis Komposit pada Kapal Pengangkut Compressed Natural Gas

    Directory of Open Access Journals (Sweden)

    Aulia Firmansah

    2013-03-01

    Full Text Available Pada penelitian ini, dilakukan analisa perbandingan pada kekuatan pressure vessel compressed natural gas. Pressure vessel yang digunakan yaitu tipe satu dan tipe tiga, tipe satu adalah tabung menggunakan material logam yaitu Carbon Steel SA 516 Grade 70 dan Aluminium Alloy T6-6061. Pada tabung tipe tiga material menggunakan Aluminium Alloy T6-6061 dengan lapisan Komposit (Carbon Fibre – Epoxy pada seluruh tabung (full wrapped. Sudut orientasi serat yang digunakan 54.73560 dan terdiri dari 4 lapis komposit yang membungkus aluminium. Variasi yang dilakukan pada tebal komposit yaitu 25% komposit, 50% komposit, dan 75% komposit. Pressure vessel mendapat perlakuan internal pressure sebesar 125 bar dan temperatur -300C. Analisa dilakukan dengan dua metode yaitu dengan perhitungan manual dan software finite element method (NASTRAN 2010. Dari hasil perhitungan tersebut tabung tipe satu dengan material logam terbukti aman karena memenuhi dari faktor keamanan yang ditentukan tetapi pressure vessel sangat berat. Pada tabung tipe tiga lamina dengan komposisi 75% komposit dan 50% komposit dinyatakan aman karena memenuhi dari kriteria tegangan maksimum. Sedangkan pada komposisi 25% komposit lamina mengalami kegagalan yang disebabkan terlalu rendahnya lapisan komposit. Dari keseluruhan hasil perhitungan dan analisa didapatkan komposisi ideal pressure vessel yaitu 75% komposit dan 25% aluminium dari tebal keseluruhan sehingga menghasilkan tegangan yang sangat kecil dan memiliki berat yang paling ringan.

  2. A sensitivity study of the oxidation of compressed natural gas on platinum

    KAUST Repository

    Badra, Jihad

    2013-11-01

    This paper presents a sensitivity study for the oxidation of methane (CH4) over platinum (Pt). Some dominant reactions in the CH 4-Pt surface chemistry were identified and the rates of these reactions were subsequently modified to enhance the calculations. Initially, a range of CH4-Pt surface mechanisms available in the literature are used, along with the relevant detailed gaseous chemistry to compute the structure of premixed compressed natural gas (CNG)/air flames co-flowing around a flat, vertical, unconfined, rectangular, and platinum plate. Comparison with existing measurements of surface temperature and species concentrations revealed significant discrepancies for all mechanisms. Sensitivity analysis has identified nine key reactions which dominate the heterogeneous chemistry of methane over platinum. The rates of these reactions were modified over a reasonable range and in different combinations leading to an "optimal" mechanism for methane/air surface chemistry on platinum. The new mechanism is then used with the same flow geometry for different cases varying the temperature of the incoming mixture (Tjet), its equivalence ratio (Φ) and the Reynolds number (Re). Results from the modified surface mechanism demonstrate reasonably good agreement with the experimental data for a wide range of operating conditions. © 2013 Elsevier Ltd. All rights reserved.

  3. Well-to-Wheels Analysis of Compressed Natural Gas and Ethanol from Municipal Solid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Uisung [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2016-10-01

    The amount of municipal solid waste (MSW) generated in the United States was estimated at 254 million wet tons in 2013, and around half of that generated waste was landfilled. There is a huge potential in recovering energy from that waste, since around 60% of landfilled material is biomass-derived waste that has high energy content. In addition, diverting waste for fuel production avoids huge fugitive emissions from landfills, especially uncontrolled CH4 emissions, which are the third largest anthropogenic CH4 source in the United States. Lifecycle analysis (LCA) is typically used to evaluate the environmental impact of alternative fuel production pathways. LCA of transportation fuels is called well-to-wheels (WTW) and covers all stages of the fuel production pathways, from feedstock recovery (well) to vehicle operation (wheels). In this study, the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET®) model developed by Argonne National Laboratory is used to evaluate WTW greenhouse gas (GHG) emissions and fossil fuel consumption of waste-derived fuels. Two waste-to-energy (WTE) pathways have been evaluated – one for compressed natural gas (CNG) production using food waste via anaerobic digestion, and the other for ethanol production from yard trimmings via fermentation processes. Because the fuel production pathways displace current waste management practices (i.e., landfilling waste), we use a marginal approach that considers only the differences in emissions between the counterfactual case and the alternative fuel production case.

  4. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Ford A. Phillips; Danny M. Deffenbaugh

    2006-05-31

    This project has documented and demonstrated the feasibility of technologies and operational choices for companies who operate the large installed fleet of integral engine compressors in pipeline service. Continued operations of this fleet is required to meet the projected growth of the U.S. gas market. Applying project results will meet the goals of the DOE-NETL Natural Gas Infrastructure program to enhance integrity, extend life, improve efficiency, and increase capacity, while managing NOx emissions. These benefits will translate into lower cost, more reliable gas transmission, and options for increasing deliverability from the existing infrastructure on high demand days. The power cylinders on large bore slow-speed integral engine/compressors do not in general combust equally. Variations in cylinder pressure between power cylinders occur cycle-to-cycle. These variations affect both individual cylinder performance and unit average performance. The magnitude of the variations in power cylinder combustion is dependent on a variety of parameters, including air/fuel ratio. Large variations in cylinder performance and peak firing pressure can lead to detonation and misfires, both of which can be damaging to the unit. Reducing the variation in combustion pressure, and moving the high and low performing cylinders closer to the mean is the goal of engine balancing. The benefit of improving the state of the engine ''balance'' is a small reduction in heat rate and a significant reduction in both crankshaft strain and emissions. A new method invented during the course of this project is combustion pressure ratio (CPR) balancing. This method is more effective than current methods because it naturally accounts for differences in compression pressure, which results from cylinder-to-cylinder differences in the amount of air flowing through the inlet ports and trapped at port closure. It also helps avoid compensation for low compression pressure by the

  5. 75 FR 38092 - The Dow Chemical Company; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-07-01

    ... positive international effects. Further details can be found in the Application. Environmental Impact Dow... Chemical Company; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY: Office of... The Dow Chemical Company (Dow), requesting blanket authorization to export liquefied natural gas (LNG...

  6. 16 CFR 1.8 - Nature, authority and use of trade regulation rules.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Nature, authority and use of trade regulation rules. 1.8 Section 1.8 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND... Nature, authority and use of trade regulation rules. (a) For the purpose of carrying out the provisions...

  7. Influence of extensive compressed natural gas (CNG) usage on air quality

    Science.gov (United States)

    Suthawaree, Jeeranut; Sikder, Helena Akhter; Jones, Charlotte Emily; Kato, Shungo; Kunimi, Hitoshi; Mohammed Hamidul Kabir, Abu Naser; Kajii, Yoshizumi

    2012-07-01

    Compressed Natural Gas (CNG) is an inexpensive, indigenous energy resource which currently accounts for the majority of automobile and domestic energy consumption in Bangladesh. This extensive CNG usage, particularly within the capital city, Dhaka, heavily influences the atmospheric composition (and hence air quality), yet to date measurements of trace gases in regions dominated by CNG emissions are relatively limited. Here we report continuous observations of the atmospherically important trace gases O3, CO, SO2, NOx and volatile organic compounds (VOC), in ambient air in Dhaka City, Bangladesh, during May 2011. The average mixing ratios of O3, CO, SO2, and NOx for the measurement period were 18.9, 520.9, 7.6 and 21.5 ppbv, respectively. The ratios of CO to NO reveal that emissions from gasoline and CNG-fuelled vehicles were dominant during the daytime (slope of ˜26), while in contrast, owing to restrictions imposed on diesel fuelled vehicles entering Dhaka City, emissions from these vehicles only became significant during the night (slope of ˜10). The total VOC mixing ratio in Dhaka was ˜5-10 times higher than the levels reported in more developed Asian cities such as Tokyo and Bangkok, which consequently gives rise to a higher ozone formation potential (OFP). However, the most abundant VOC in Dhaka were the relatively long-lived ethane and propane (with mean mixing ratios of ˜115 and ˜30 ppbv, respectively), and as a consequence, the ozone formation potential per ppb carbon (ppbC) was lower in Dhaka than in Tokyo and Bangkok. Thus the atmospheric composition of air influenced by extensive CNG combustion may be characterized by high VOC mixing ratios, yet mixing ratios of the photochemical pollutant ozone do not drastically exceed the levels typical of Asian cities with considerably lower VOC levels.

  8. Economical and environmental assessments of compressed natural gas for diesel vehicle in Thailand

    Directory of Open Access Journals (Sweden)

    Prateep Chouykerd

    2008-08-01

    Full Text Available The economic assessments for the use of compressed natural gas as fuel for several types of diesel vehicles, rarely pick up, non-fixed route truck and private truck, were studied. It is noted that two main technologies of diesel natural gas vehicle (NGV, i.e. dedicated retrofit and diesel dual fuel (DDF, were considered in this work. It was found that the dedicated retrofit needs higher investment costs than dual fuel, but can achieve higher diesel saving than dual fuel. In detail, the payback period of dual fuel non-fixed route truck was found to be identical to dual fuel private truck both in the cases of6 wheel and 10 wheel, while dedicated retrofit non-fixed route truck and private truck are also identical and have longerpay back period than dual fuel due to its higher conversion costs.This work also presents the emissions released from all types of engines especially green house gas CO2. It was found that, in the case of light duty diesel i.e. pickup truck, dedicated retrofit emitted high level of CO2 than both dual fuel and conventional diesel engines. For heavy duty i.e. non-fixed route truck and private truck vehicles, dedicated retrofit emitted a lower level of CO2 than normal diesel engine. Other pollutants from engine emission, i.e. hydrocarbon (HC,nitric oxide (NOx, carbon monoxide (CO and particulate matter, (PM were also observed. The results indicated that, inthe case of light duty diesel, dedicated retrofit engine emits higher levels of HC and CO than diesel engine; in contrast, it emits lower level of NOx and PM than diesel and dual fuel. Dual fuel emits HC and CO higher than diesel and dedicated retrofit but emits lower level of NOx and PM than diesel. Lastly, for heavy duty diesel, it was demonstrated that non-fixed route truck and private truck heavy duty dedicated retrofit have potential to reduce emissions of HC, NOx, CO and PM when compared to normal heavy duty diesel. Engine efficiencies under dual fuel and dedicated

  9. Unregulated emissions from compressed natural gas (CNG) transit buses configured with and without oxidation catalyst.

    Science.gov (United States)

    Okamoto, Robert A; Kado, Norman Y; Kuzmicky, Paul A; Ayala, Alberto; Kobayashi, Reiko

    2006-01-01

    The unregulated emissions from two in-use heavy-duty transit buses fueled by compressed natural gas (CNG) and equipped with oxidation catalyst (OxiCat) control were evaluated. We tested emissions from a transit bus powered by a 2001 Cummins Westport C Gas Plus 8.3-L engine (CWest), which meets the California Air Resources Board's (CARB) 2002 optional NOx standard (2.0 g/bhp-hr). In California, this engine is certified only with an OxiCat, so our study did not include emissions testing without it. We also tested a 2000 New Flyer 40-passenger low-floor bus powered by a Detroit Diesel series 50G engine (DDCs50G) that is currently certified in California without an OxiCat. The original equipment manufacturer (OEM) offers a "low-emission" package for this bus that includes an OxiCat for transit bus applications, thus, this configuration was also tested in this study. Previously, we reported that formaldehyde and other volatile organic emissions detected in the exhaust of the DDCs50G bus equipped with an OxiCat were significantly reduced relative to the same DDCs50G bus without OxiCat. In this paper, we examine othertoxic unregulated emissions of significance. The specific mutagenic activity of emission sample extracts was examined using the microsuspension assay. The total mutagenic activity of emissions (activity per mile) from the OxiCat-equipped DDC bus was generally lower than that from the DDC bus without the OxiCat. The CWest bus emission samples had mutagenic activity that was comparable to that of the OxiCat-equipped DDC bus. In general, polycyclic aromatic hydrocarbon (PAH) emissions were lower forthe OxiCat-equipped buses, with greater reductions observed for the volatile and semivolatile PAH emissions. Elemental carbon (EC) was detected in the exhaust from the all three bus configurations, and we found that the total carbon (TC) composition of particulate matter (PM) emissions was primarily organic carbon (OC). The amount of carbon emissions far exceeded the

  10. Developing a Natural Gas-Powered Bus Rapid Transit Service: A Case Study on Leadership: Roaring Fork Transportation Authority (Presentation); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, A.

    2015-03-01

    The Roaring Fork Transportation Authority (RFTA) represents a series of unique successes in alternative fuel deployment by pushing the envelope with innovative solutions. In the last year, RFTA demonstrated the ability to utilize compressed natural gas buses at a range of altitudes, across long distances, in extreme weather conditions and in a modern indoor fueling and maintenance facility - allwhile saving money and providing high-quality customer service. This case study will highlight how the leadership of organizations and communities that are implementing advances in natural gas vehicle technology is paving the way for broader participation.

  11. TECHNOLOGIES TO ENHANCE THE OPERATION OF EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE - MANIFOLD DESIGN FOR CONTROLLING ENGINE AIR BALANCE

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Bourn; Ford A. Phillips; Ralph E. Harris

    2005-12-01

    This document provides results and conclusions for Task 15.0--Detailed Analysis of Air Balance & Conceptual Design of Improved Air Manifolds in the ''Technologies to Enhance the Operation of Existing Natural Gas Compression Infrastructure'' project. SwRI{reg_sign} is conducting this project for DOE in conjunction with Pipeline Research Council International, Gas Machinery Research Council, El Paso Pipeline, Cooper Compression, and Southern Star, under DOE contract number DE-FC26-02NT41646. The objective of Task 15.0 was to investigate the perceived imbalance in airflow between power cylinders in two-stroke integral compressor engines and develop solutions via manifold redesign. The overall project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity.

  12. 78 FR 35014 - Orders Granting Authority to Import and Export Natural Gas, and to Import Liquefied Natural Gas...

    Science.gov (United States)

    2013-06-11

    .... and 4:30 p.m., Monday through Friday, except Federal holidays. Issued in Washington, DC, on May 29... gas from/to Canada/ Mexico. 3266 04/12/13 13-38-LNG APS-American Power Order granting blanket Supply, LLC. authority to import natural gas from Canada and to import LNG from various international sources...

  13. Use of compressed natural gas in automotive vehicles; Uso del gas natural comprimido aplicado en vehiculos automotores

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, Adrian [Comision Nacional para el Ahorro de Energia (CONAE) (Mexico)

    2005-07-01

    The natural gas is natural origin energy (fossil fuel); it contains predominantly 90 percent methane; does not require transformation process for its use; is supplied the 24 hours to commerce, industries and homes by underground pipes; it is lighter than air; it is not corrosive, nor absorbent or toxic. For those reasons a study was performed where it is widely justified why the natural gas ought to be used in vehicles. [Spanish] El gas natural es un energetico de origen natural (combustible fosil), contiene predominantemente 90 por ciento de metano, no requiere proceso de transformacion para su utilizacion, llega directamente las 24 horas del dia a los hogares, comercios e industrias por tuberias subterraneas, es mas ligero que el aire, no es corrosivo, no es absorbente y no es toxico. Por esas razones se hizo un estudio donde se justifica ampliamente porque el gas natural debe utilizarse en vehiculos.

  14. In-vehicle measurement of ultrafine particles on compressed natural gas, conventional diesel, and oxidation-catalyst diesel heavy-duty transit buses.

    Science.gov (United States)

    Hammond, Davyda; Jones, Steven; Lalor, Melinda

    2007-02-01

    Many metropolitan transit authorities are considering upgrading transit bus fleets to decrease ambient criteria pollutant levels. Advancements in engine and fuel technology have lead to a generation of lower-emission buses in a variety of fuel types. Dynamometer tests show substantial reductions in particulate mass emissions for younger buses (vehicle particle number concentration measurements on conventional diesel, oxidation-catalyst diesel and compressed natural gas transit buses are compared to estimate relative in-vehicle particulate exposures. Two primary consistencies are observed from the data: the CNG buses have average particle count concentrations near the average concentrations for the oxidation-catalyst diesel buses, and the conventional diesel buses have average particle count concentrations approximately three to four times greater than the CNG buses. Particle number concentrations are also noticeably affected by bus idling behavior and ventilation options, such as, window position and air conditioning.

  15. CNG (Compressed natural gas) engine M366 G for electric power generation; Motor M 366 G movido a gas metano veicular versao industrial: aplicacao grupo gerador

    Energy Technology Data Exchange (ETDEWEB)

    Muraro, Wilson; Shiraiwa, Nilton Mitsuro [DaimlerChrysler do Brasil Ltda., Sao Bernardo do Campo, SP (Brazil); Mantovani, Wladimir Tadeu [Woodward Governor Company, Fort Collins, CO (United States)

    2004-07-01

    Daimler-Chrysler of Brazil developed the M 366 G engine, in the industrial version, using compressed natural gas. This product has the combustion with lambda 1.0, it is a 6-cylinder engine in line with displacement compressor of 5.958 cm{sup 3} , power of 65 kW @ 1800 min{sup 1} (60Hz) and power of 55 kW @ 1500 min{sup 1} (50Hz). The equipment for rotation control, ignition, reducing gas and stabilizer were specially developed for industrial motors with CNG supply for the Fca Woodward. This paper presents the results of tests made on bank of evidence and test field, which showed the good performance of the product. (author)

  16. The relationship between the political authorities and the commercial actors in the European natural gas market

    International Nuclear Information System (INIS)

    Mjelde, Jarle Christian

    1998-01-01

    In summarizing the reasons for the fall of the Roman empire one has found about 210 significant ones. Without too much comparison the Roman empire and the EU natural gas market have similarities in connections between political authorities and the commercial actors in the European natural gas market. The area has consisted of several independent markets with different solutions that from 1988 has been tried integrated in an inner energy market. Several governmental and private actors have interest in this sector and both inhabitants and businesses are affected by alterations in a national natural gas market. This process is not yet finished. The thesis gives a broad description of the topic by including as many as possible of the EU member states. The topic is large and complex and the author has had to make a choice which parts to emphasize. There are chapters on the theoretical basis, the natural gas industry, what factors may explain the relationship between the political authorities and the commercial actors in the national natural gas market in each EU member and how does the EU Commission goals regarding free competition in the energy market affect the relationship between the political authorities and commercial actors in the national natural gas market

  17. Natural Frequencies of a Cracked Beam Coupled with a Compressible Sloshing Fluid

    Directory of Open Access Journals (Sweden)

    Michele Di Sciuva

    2004-01-01

    Full Text Available This article describes studies into the flexural vibration of a cracked cantilevered beam in contact with a non-viscous fluid. The crack has been represented by a mass-less rotational spring, the flexibility of which has been calculated using linear fracture mechanics. The coupled system is subject to undisturbed boundary condition at infinity in the fluid domain. A range of different boundary conditions have been analysed such as both incompressible and compressible fluid, with and without sloshing. Various crack sizes and positions have been considered in order to assess the effect of damage in the fluid-structure interaction problem.

  18. 78 FR 4401 - Orders Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied...

    Science.gov (United States)

    2013-01-22

    ... USA, Inc. authority to import/ export natural gas from/to Canada/Mexico. 3159 10/05/12 12-120-NG... DEPARTMENT OF ENERGY Orders Granting Authority To Import and Export Natural Gas, To Import and... gives notice that during October 2012, it issued orders granting authority to import and export natural...

  19. Compressed Counting Meets Compressed Sensing

    OpenAIRE

    Li, Ping; Zhang, Cun-Hui; Zhang, Tong

    2013-01-01

    Compressed sensing (sparse signal recovery) has been a popular and important research topic in recent years. By observing that natural signals are often nonnegative, we propose a new framework for nonnegative signal recovery using Compressed Counting (CC). CC is a technique built on maximally-skewed p-stable random projections originally developed for data stream computations. Our recovery procedure is computationally very efficient in that it requires only one linear scan of the coordinates....

  20. 78 FR 34084 - Freeport-McMoRan Energy LLC; Application for Long-Term Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2013-06-06

    ... Michael Levi, A Strategy for U.S. Natural Gas Exports, prepared for The Hamilton Project, at 25 (June 2012...-Term Authorization To Export Liquefied Natural Gas Produced From Domestic Natural Gas Resources to Non... LLC (FME), requesting long-term, multi-contract authorization to export liquefied natural gas (LNG...

  1. 78 FR 44940 - Orders Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied...

    Science.gov (United States)

    2013-07-25

    ... Company. authority to import/ export natural gas from/ to Mexico. 3287 05/23/13 13-56-NG GDF SUEZ Gas NA... to export natural gas to Mexico and to export LNG to Mexico by vessel and by truck. BILLING CODE 6450... Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied Natural Gas During...

  2. 77 FR 4028 - Orders Granting, Amending and Vacating Authority To Import and Export Natural Gas and Liquefied...

    Science.gov (United States)

    2012-01-26

    ... authority to export natural gas to Mexico. 3041 12/07/11 11-127-LNG Jordan Cove Energy Order granting long... Granting, Amending and Vacating Authority To Import and Export Natural Gas and Liquefied Natural Gas FE Docket Nos. Gas Natural Caxitlan, S. DE R.L 11-147-NG Jordan Cove Energy Project, L.P 11-127-LNG Irving...

  3. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    Energy Technology Data Exchange (ETDEWEB)

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen’s significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  4. 76 FR 6491 - San Diego County Water Authority Subregional Natural Community Conservation Program/Habitat...

    Science.gov (United States)

    2011-02-04

    ...] San Diego County Water Authority Subregional Natural Community Conservation Program/Habitat Conservation Plan, San Diego and Riverside Counties, CA; Final Environmental Impact Statement and Habitat... Program/Habitat Conservation Plan (NCCP/HCP), which the applicant has submitted with their incidental take...

  5. 78 FR 30918 - Natural Gas Pipeline Company of America LLC; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2013-05-23

    ....208, and 157(213) of the Commission's Regulations under the Natural Gas Act (NGA) as amended, requesting authority to convert one (1.0) Bcf of cushion gas to working gas at its Herscher Mount Simon... flexibility with the ability to withdraw additional working gas from the Mount Simon Reservoir instead of the...

  6. Representing the nature of science in a science textbook: Exploring author-editor-publisher interactions

    Science.gov (United States)

    Digiuseppe, Maurizio

    Current reforms in elementary and secondary science education call for students and teachers to develop more informed views of the nature of science---a process in which learning materials like science textbooks play a significant role. This dissertation reports on a case study of the development of representations of the nature of science in one unit of a senior high school chemistry textbook by the book's author, editor, and publisher. The study examines the multiple discourses that arose as the developers reflected on their personal and shared understandings of the nature of science; squared these understandings with mandated curricula, the educational needs of chemistry students and teachers, and the exigencies of large-scale commercial textbook publishing; and developed and incorporated into the textbook representations of the nature of science they believed were the most suitable. Analyses of the data in this study indicate that a number of factors significantly influenced the development of representations of the nature of science, including representational accuracy (the degree to which suggested representations of the nature of science conformed to what the developers believed were contemporary understandings of the nature of science), representational consistency (the degree to which similar representations of the nature of science in different parts of the textbook conveyed the same meaning), representational appropriateness (the age-, grade-, and reading-level suitability of the suggested nature of science representations), representational alignment (the degree to which suggested representations of the nature of science addressed the requirements of mandated curricula), representational marketability (the degree to which textbook developers believed suggested representations of the nature of science would affect sales of the textbook in the marketplace), and a number of "Workplace Resources" factors such as the availability of time, relevant expertise

  7. Hot surface assisted compression ignition in a direct injection natural gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Aesoey, Vilmar

    1996-12-31

    This study investigates the problem of ignition in a direct injection natural gas engine. Due to poor auto-ignition properties of natural gas compared to regular diesel engine fuels, a special arrangement to assist and secure ignition is required. The objective was to investigate the feasibility of using a hot surface as ignition assistance, primarily for application in medium and large size engines, and further study the main mechanisms involved in the ignition process. A constant volume combustion bomb and a test engine are used for experiments, supported by theoretical analysis and numerical simulations. Variable composition of natural gas depending on the gas source and over time, is a important problem causing significant variation in ignition properties. It is shown that even small quantities of non-methane components, which are normally present in natural gases, strongly influence ignition. Actions to handle the ignition problem caused by variable natural composition, are also discussed. In order to estimate the ignition properties of natural gas, a simple correlation to gas composition is proposed, showing good correlation to the experimental data. Mathematical models for simulation of the processes are developed based on fundamental physical relations and experimental results. They are mainly used in this study to support and analyze the physical experiments, but can also be useful in future design and optimization processes. 71 refs., 80 figs., 6 tabs.

  8. The Effect of Injection Timings on Performance and Emissions of Compressed Natural-Gas Direct Injection Engine

    Directory of Open Access Journals (Sweden)

    Saad Aljamali

    2016-01-01

    Full Text Available This experimental part investigates the effect of injection timing on performance and emissions of homogenous mixture compressed natural-gas direct injection. The engine of 1.6 L capacity, 4 cylinders, spark ignition, and compression ratio of 14 was used. Performance and emission were recorded under wide-open throttle using an engine control system (Rotronics and the portable exhaust gas analyser (Kane. The engine was tested at speed ranging from 1500 revolutions per minute (RPM to 4000 RPM with 500 RPM increments. The engine control unit (ECU was modified using Motec 800. The injection timings investigated were at the end of injection (EOI 120 bTDC, 180 bTDC, 300 bTDC, and 360 bTDC. Results show high brake power, torque, and BMEP with 120 as compared with the other injection timings. At 4000 RPM the power, torque, and BMEP with 120 were 5% compared to that with 180. Furthermore, it shows low BSFC and high fuel conversion efficiency with 120. With 360, the engine produced less CO and CO2 at higher speeds.

  9. Diesel versus compressed natural gas in Transmilenio-Bogotá: innovation, precaution, and distribution of risk

    DEFF Research Database (Denmark)

    Pineda, Andres Felipe Valderrama

    2007-01-01

    During the period 1998–2000, municipal officials in Bogotá implemented a new transportation system for the city. Transmilenio became the first major mass transportation system in the world to use only buses. The authors examine here the process that led to the design decision to power all of the ...

  10. 77 FR 63806 - Southern LNG Company, L.L.C.; Application for Long-Term Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2012-10-17

    ...-Term Authorization To Export Liquefied Natural Gas Produced From Domestic Natural Gas Resources to Non....C. (Southern LNG), requesting long-term, multi-contract authorization to export up to 4 million tons... pipelines of Southern Natural Gas Company, L.L.C., Elba Express Company, L.L.C., Carolina Gas Transmission...

  11. 78 FR 65304 - Orders Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied...

    Science.gov (United States)

    2013-10-31

    ... Canada and to export natural gas to Mexico. 3319 08/01/13 13-84-LNG Hartland Fuel Order granting blanket... natural gas to Mexico. 3323 08/01/13 13-86-NG Just Energy New York Order granting blanket Corp. authority... blanket authority to import/export natural gas from/to Canada/ Mexico. BILLING CODE 6450-01-P ...

  12. Compression strength perpendicular to grain of Serbian spruce (Picea omorika (Pančić purkyně wood from plantations and natural stands

    Directory of Open Access Journals (Sweden)

    Petrović Danijela

    2017-01-01

    Full Text Available This paper presents the results of testing the compression of Serbian spruce wood from plantations and natural stands. Compression perpendicular to grain in radial and tangential direction was tested. A dilatation of 1% was taken for a conditional boundary dilatation, and the appropriate strength for the conditional limit strength was taken. Six trees from plantations and nine trees from natural stands were analyzed. In total, 309 samples were tested. The regression analysis examined the dependence of these mechanical properties on the width of the annual rings, the percentage of late wood and wood density.

  13. Hydrogen enriched compressed natural gas (HCNG: A futuristic fuel for internal combustion engines

    Directory of Open Access Journals (Sweden)

    Nanthagopal Kasianantham

    2011-01-01

    Full Text Available Air pollution is fast becoming a serious global problem with increasing population and its subsequent demands. This has resulted in increased usage of hydrogen as fuel for internal combustion engines. Hydrogen resources are vast and it is considered as one of the most promising fuel for automotive sector. As the required hydrogen infrastructure and refueling stations are not meeting the demand, widespread introduction of hydrogen vehicles is not possible in the near future. One of the solutions for this hurdle is to blend hydrogen with methane. Such types of blends take benefit of the unique combustion properties of hydrogen and at the same time reduce the demand for pure hydrogen. Enriching natural gas with hydrogen could be a potential alternative to common hydrocarbon fuels for internal combustion engine applications. Many researchers are working on this for the last few years and work is now focused on how to use this kind of fuel to its maximum extent. This technical note is an assessment of HCNG usage in case of internal combustion engines. Several examples and their salient features have been discussed. Finally, overall effects of hydrogen addition on an engine fueled with HCNG under various conditions are illustrated. In addition, the scope and challenges being faced in this area of research are clearly described.

  14. A Comparative study on VOCs and aldehyde-ketone emissions from a spark Ignition vehicle fuelled on compressed natural gas and gasoline

    International Nuclear Information System (INIS)

    Shah, A.N.

    2012-01-01

    In this work, an experimental study was conducted on a spark ignition (SI) vehicle fuelled on compressed natural gas (CNG), and gasoline to compare the unregulated emissions such as volatile organic compounds (VOCs) and aldehyde-ketones or carbonyls. In the meantime, ozone forming potential (OFP) of pollutants was also calculated on the basis of their specific reactivity (SR). The vehicle was run on a chassis dynamometer following the Chinese National Standards test scheduled for light duty vehicle (LDV) emissions. According to the results, total aldehyde-ketones were increased by 39.4% due to the substantial increase in formaldehyde and acrolein + acetone emissions, while VOCs and BTEX (benzene, toluene, ethyl benzene, and xylene) reduced by 85.2 and 86% respectively, in case of CNG fuelled vehicle as compared to gasoline vehicle. Although total aldehyde-ketones were higher with CNG relative to gasoline, their SR was lower due decrease in acetaldehyde, propionaldehyde, crotonaldehyde, and methacrolein species having higher maximum incremental reactivity (MIR) values. The SR of VOCs and aldehyde-ketones emitted from CNG fuelled vehicle was decreased by above 10% and 32% respectively, owing to better physicochemical properties and more complete burning of CNG as compared to gasoline. (author)

  15. Assessment of air quality after the implementation of compressed natural gas (CNG) as fuel in public transport in Delhi, India.

    Science.gov (United States)

    Ravindra, Khaiwal; Wauters, Eric; Tyagi, Sushil K; Mor, Suman; Van Grieken, René

    2006-04-01

    Public transport in Delhi was amended by the Supreme Court of India to use Compressed Natural Gas (CNG) instead of diesel or petrol. After the implementation of CNG since April 2001, Delhi has the highest fraction of CNG-run public vehicles in the world and most of them were introduced within 20 months. In the present study, the concentrations of various criteria air pollutants (SPM, PM(10), CO, SO(2) and NO(x)) and organic pollutants such as benzene, toluene, xylene (BTX) and polycyclic aromatic hydrocarbons (PAHs) were assessed before and after the implementation of CNG. A decreasing trend was found for PAHs, SO(2) and CO concentrations, while the NO(x) level was increased in comparison to those before the implementation of CNG. Further, SPM, PM(10), and BTX concentrations showed no significant change after the implementation of CNG. However, the BTX concentration demonstrated a clear relation with the benzene content of gasoline. In addition to the impact of the introduction of CNG the daily variation in PAHs levels was also studied and the PAHs concentrations were observed to be relatively high between 10 pm to 6 am, which gives a proof of a relation with the limited day entry and movement of heavy vehicles in Delhi.

  16. 32 CFR 537.15 - Statutory authority for maritime claims and claims involving civil works of a maritime nature.

    Science.gov (United States)

    2010-07-01

    ... claims involving civil works of a maritime nature. 537.15 Section 537.15 National Defense Department of....15 Statutory authority for maritime claims and claims involving civil works of a maritime nature. (a... affirmative claims involving civil works of a maritime nature is set out at 33 U.S.C. 408. ...

  17. A comparative life cycle assessment of diesel and compressed natural gas powered refuse collection vehicles in a Canadian city

    International Nuclear Information System (INIS)

    Rose, Lars; Hussain, Mohammed; Ahmed, Syed; Malek, Kourosh; Costanzo, Robert; Kjeang, Erik

    2013-01-01

    Consumers and organizations worldwide are searching for low-carbon alternatives to conventional gasoline and diesel vehicles to reduce greenhouse gas (GHG) emissions and their impact on the environment. A comprehensive technique used to estimate overall cost and environmental impact of vehicles is known as life cycle assessment (LCA). In this article, a comparative LCA of diesel and compressed natural gas (CNG) powered heavy duty refuse collection vehicles (RCVs) is conducted. The analysis utilizes real-time operational data obtained from the City of Surrey in British Columbia, Canada. The impact of the two alternative vehicles is assessed from various points in their life. No net gain in energy use is found when a diesel powered RCV is replaced by a CNG powered RCV. However, significant reductions (approximately 24% CO 2 -equivalent) in GHG and criteria air contaminant (CAC) emissions are obtained. Moreover, fuel cost estimations based on 2011 price levels and a 5-year lifetime for both RCVs reveal that considerable cost savings may be achieved by switching to CNG vehicles. Thus, CNG RCVs are not only favorable in terms of reduced climate change impact but also cost effective compared to conventional diesel RCVs, and provide a viable and realistic near-term strategy for cities and municipalities to reduce GHG emissions. - Highlights: ► Life cycle analysis is performed on two alternative refuse collection vehicle technologies. ► Real-time operational data obtained by the City of Surrey in British Columbia are utilized. ► The life cycle energy use is similar for diesel and CNG RCVs. ► A 24% reduction of GHG emissions (CO 2 -equivalent) may be realized by switching from diesel to CNG. ► CNG RCVs are estimated to be cost effective and may lead to reduced fuel costs.

  18. Effect of diesel pre-injection timing on combustion and emission characteristics of compression ignited natural gas engine

    International Nuclear Information System (INIS)

    Xu, Min; Cheng, Wei; Zhang, Hongfei; An, Tao; Zhang, Shaohua

    2016-01-01

    Highlights: • Pre-injection timing on combustion and emission of CING engine are studied. • Closely pre-injection operations leads to increase of combustion intensity. • Early pre-injection operations leads to lower combustion intensity. • Early pre-injection modes provide better NO x emission. - Abstract: Pre-injection strategy is considered to be one of the most important ways to improve diesel engine performance, emission and combustion. It is the same important factor in pilot diesel compression ignition natural gas (CING) engine. In this study, effects of pre-injection timing on combustion and emission performances were experimentally studied in a CING engine which was modified from a turbocharged six-cylinder diesel engine. The experiments were conducted at constant speed of 1400 rpm and different engine loads with a constant fuel injection pressure of 1100 bar. Main injection timing was fixed at 10 °CA BTDC in the advance process of pre-injection timing. The cylinder pressure, heart release rate (HRR), pressure rise rate (PRR), start of combustion (SOC) and coefficient of variation (COV IMEP ), as well as NO x , HC and CO emissions were analyzed. The results indicated that closely pre-injection operations lead to the advance of SOC which intensified combustion of in-cylinder mixture, thereby resulting in higher cylinder pressure, HRR and PRR, as well higher NO x emissions and lower HC and CO emissions. However, early pre-injection operations lead to lower cylinder pressure, HRR and PRR due to decreasing in combustion intensity. Pre-injection timing of 70 °CA BTDC is a conversion point in which influence of pre-injection fuel on ignition and combustion of natural gas nearly disappeared and lowest NO x emission could be obtained. Compared with single injection ignition mode, NO x emissions at the conversion point were reduced by 33%, 38% and 7% at engine load of 38%, 60% and 80% respectively. This is important for the conditions that ignition fuel

  19. Effect of Diesel Engine Converted to Sequential Port Injection Compressed Natural Gas Engine on the Cylinder Pressure vs Crank Angle in Variation Engine Speeds

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is b...

  20. An analysis of price competitiveness of CNG (compressed natural gas) versus gasoline: estimation of the elasticities of demand by CNG in a recent period in Brazil; Uma analise da competitividade de preco do GNV (Gas Natural Veicular) frente a gasolina: estimacao das elasticidades da demanda por GNV no Brasil no periodo recente

    Energy Technology Data Exchange (ETDEWEB)

    Iootty, Mariana; Pinto Junior, Helder; Roppa, Bruna; Biasi, Guilherme de [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Economia

    2004-07-01

    One of the main determinants to the expansion of natural gas on the Brazilian domestic market is its price. Hence, it is important to analyze the price competitiveness of natural gas vis-a-vis its competitors. The current paper focuses on the market of natural gas in vehicles (the compressed natural gas - CNG), and uses co-integration techniques to estimate the price-elasticity of CNG, the cross-elasticity of CNG and gasoline, and the income-elasticity. The results suggest that price is a relevant factor in the long-run, while in the short-run income is the most significant determinant of the demand variation. In addition, the paper also shows an imperfect substitutability between CNG and gasoline. (author)

  1. Mechanical stability of a salt cavern submitted to rapid pressure variations: Application to the underground storage of natural gas, compressed air and hydrogen

    International Nuclear Information System (INIS)

    Djizanne-Djakeun, Hippolyte

    2014-01-01

    Salt caverns used for the underground storage of large volumes of natural gas are in high demand given the ever-increasing energy needs. The storage of renewable energy is also envisaged in these salt caverns for example, storage of compressed air and hydrogen mass storage. In both cases, salt caverns are more solicited than before because they are subject to rapid injection and withdrawal rates. These new operating modes raise new mechanical problems, illustrated in particular by sloughing, and falling of overhanging blocks at cavern wall. Indeed, to the purely mechanical stress related to changes in gas pressure variations, repeated dozens of degrees Celsius of temperature variation are superimposed; causes in particular during withdrawal, additional tensile stresses whom may lead to fractures at cavern wall; whose evolution could be dangerous. The mechanical behavior of rock salt is known: it is elasto-viscoplastic, nonlinear and highly thermo sensitive. The existing rock salt constitutive laws and failures and damages criteria have been used to analyze the behavior of caverns under the effects of these new loading. The study deals with the thermo mechanics of rocks and helps to analyze the effects of these new operations modes on the structural stability of salt caverns. The approach was to firstly design and validate a thermodynamic model of the behavior of gas in the cavern. This model was used to analyze blowout in gas salt cavern. Then, with the thermo mechanical coupling, to analyze the effects of rapid withdrawal, rapid injection and daily cycles on the structural stability of caverns. At the experimental level, we sought the optimal conditions to the occurrence and the development of cracks on a pastille and a block of rock salt. The creep behavior of rock salt specimens in triaxial extension also was analyzed. (author)

  2. 77 FR 64964 - Cheniere Marketing, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas...

    Science.gov (United States)

    2012-10-24

    ... DEPARTMENT OF ENERGY [FE Docket No. 12-97-LNG] Cheniere Marketing, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced From Domestic Natural Gas Resources to Non-Free Trade... application (Application) filed on August 31, 2012, by Cheniere Marketing, LLC (CMI), requesting long- term...

  3. 78 FR 53739 - Orders Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied...

    Science.gov (United States)

    2013-08-30

    ... RENEWABLE ENERGY, LLC)........ TIDAL ENERGY MARKETING (U.S.) LLC) 13-75-NG HUDSON ENERGY SERVICES, LLC) 13... Energy, LLC. import natural gas from Canada/Mexico. 3304..... 07/11/13 13-75-NG......... Tidal Energy... DEPARTMENT OF ENERGY Orders Granting Authority To Import and Export Natural Gas, To Import and...

  4. The three-dimensional nature of microbands in a channel die compressed Goss-oriented Ni single crystal

    International Nuclear Information System (INIS)

    Afrin, N.; Quadir, M.Z.; Bassman, L.; Driver, J.H.; Albou, A.; Ferry, M.

    2011-01-01

    The three-dimensional structure of microband boundaries in a plane strain compressed Goss-oriented nickel single crystal was generated by the electron backscatter diffraction technique. Rather than being perfectly planar, microband boundaries generally contained bumps and curves. The planar segments of these boundaries have orientations that coincide closely with one of the expected {1 1 1} slip planes of this crystal.

  5. 78 FR 19696 - Orders Granting Authority To Import and Export Natural Gas, To Import Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-02

    ... PIPELINE COMPANY 12-160-NG ENERGIA CHIHUAHUA, S.A. DE C.V 12-162-NG MEXICANA DE COBRE, S.A. DE C.V 12-163... to Mexico. 3206 12/03/12 12-163-NG Mexicana de Cobre, Order granting blanket S.A. de C.V. authority...

  6. PERHITUNGAN HARGA POKOK PRODUK COMPRESSED NATURAL GAS DARI LANDFILL GAS SEBAGAI ENERGI ALTERNATIF PADA TPST BANTAR GEBANG, BEKASI

    Directory of Open Access Journals (Sweden)

    Srilarakasuri P Ardiagarini

    2013-06-01

    sanitary landfill waste; CNG is compressed natural gas of CH4. CNG can be used as an altenative fuel for transport vehicles. LFG can be converted to CNG using Acrion CO2 WASH l machine which detaches CH4 from other gas. The LFG used to calculate cost of goods sold of this product is only five percent of the total LFG capacity that can presently be produced at TPST Bantar Gebang. The input is LFG of 7,500 Nm3/day and the output is CNG of 3,570 Nm3/day. Two time-point scenarios are used in the cost of goods sold calculation: five years and 10 years. Total expenditure at those time-points is divided by CNG capacity produced each year. The product’s costs of goods sold in five years time is Rp 160/litre and in ten years time is Rp 150/liter. Key words: renewable energy, biogas, TPST bantar gebang, LFG, CNG  ,cost of goods sold

  7. Starting up a programme of atomic piles using compressed gas

    International Nuclear Information System (INIS)

    Horowitz, J.; Yvon, J.

    1959-01-01

    1) An examination of the intellectual and material resources which have directed the French programme towards: a) the natural uranium and plutonium system, b) the use of compressed gas as heat transfer fluid (primary fluid). 2) The parts played in exploring the field by the pile EL2 and G1, EL2 a natural uranium, heavy water and compressed gas pile, G1 a natural uranium, graphite and atmospheric air pile. 3) Development of the neutronics of graphite piles: physical study of G1. 4) The examination of certain problem posed by centres equipped with natural uranium, graphite and compressed carbon dioxide piles: structure, special materials, fluid circuits, maximum efficiency. Economic aspects. 5) Aids to progress: a) piles for testing materials and for tests on canned fuel elements, b) laboratory and calculation facilities. 6) Possible new orientations of compressed gas piles: a) raising of the pressure, b) enriched fuel, c) higher temperatures, d) use of heavy water. (author) [fr

  8. Compressed sensing & sparse filtering

    CERN Document Server

    Carmi, Avishy Y; Godsill, Simon J

    2013-01-01

    This book is aimed at presenting concepts, methods and algorithms ableto cope with undersampled and limited data. One such trend that recently gained popularity and to some extent revolutionised signal processing is compressed sensing. Compressed sensing builds upon the observation that many signals in nature are nearly sparse (or compressible, as they are normally referred to) in some domain, and consequently they can be reconstructed to within high accuracy from far fewer observations than traditionally held to be necessary. Apart from compressed sensing this book contains other related app

  9. Volatile organic compounds in a residential and commercial urban area with a diesel, compressed natural gas and oxygenated gasoline vehicular fleet.

    Science.gov (United States)

    Martins, Eduardo Monteiro; Arbilla, Graciela; Gatti, Luciana Vanni

    2010-02-01

    Air samples were collected in a typical residential and commercial area in Rio de Janeiro, Brazil, where buses and trucks use diesel and light duty vehicles use compressed natural gas, ethanol, and gasohol (gasoline blended with ethanol) as fuel. A total of 66 C3-C12 volatile organic compounds (VOCs) were identified. The most abundant compounds, on a mass concentration basis, included propane, isobutane, i-pentane, m,p-xylene, 1,3,5-trimethylbenzene, toluene, styrene, ethylbenzene, isopropylbenzene, o-xylene and 1,2,4-trimethylbenzene. Two VOCs photochemical reactivity rankings are presented: one involves reaction with OH and the other involves production of ozone.

  10. Efficient predictive algorithms for image compression

    CERN Document Server

    Rosário Lucas, Luís Filipe; Maciel de Faria, Sérgio Manuel; Morais Rodrigues, Nuno Miguel; Liberal Pagliari, Carla

    2017-01-01

    This book discusses efficient prediction techniques for the current state-of-the-art High Efficiency Video Coding (HEVC) standard, focusing on the compression of a wide range of video signals, such as 3D video, Light Fields and natural images. The authors begin with a review of the state-of-the-art predictive coding methods and compression technologies for both 2D and 3D multimedia contents, which provides a good starting point for new researchers in the field of image and video compression. New prediction techniques that go beyond the standardized compression technologies are then presented and discussed. In the context of 3D video, the authors describe a new predictive algorithm for the compression of depth maps, which combines intra-directional prediction, with flexible block partitioning and linear residue fitting. New approaches are described for the compression of Light Field and still images, which enforce sparsity constraints on linear models. The Locally Linear Embedding-based prediction method is in...

  11. "Compressed" Compressed Sensing

    OpenAIRE

    Reeves, Galen; Gastpar, Michael

    2010-01-01

    The field of compressed sensing has shown that a sparse but otherwise arbitrary vector can be recovered exactly from a small number of randomly constructed linear projections (or samples). The question addressed in this paper is whether an even smaller number of samples is sufficient when there exists prior knowledge about the distribution of the unknown vector, or when only partial recovery is needed. An information-theoretic lower bound with connections to free probability theory and an upp...

  12. Mechanical chest compressions.

    Science.gov (United States)

    Pomeroy, Matthew

    2012-09-13

    The authors of this study state that there is a lack of evidence about the efficiency of mechanical devices in producing chest compressions as an adjunct to resuscitation during cardiorespiratory arrest.

  13. The co-evolution of alternative fuel infrastructure and vehicles: A study of the experience of Argentina with compressed natural gas

    International Nuclear Information System (INIS)

    Collantes, Gustavo; Melaina, Marc W.

    2011-01-01

    In a quest for strategic and environmental benefits, the developed countries have been trying for many years to increase the share of alternative fuels in their transportation fuel mixes. They have met very little success though. In this paper, we examine the experience of Argentina with compressed natural gas. We conducted interviews with a wide range of stakeholders and analyzed econometrically data collected in Argentina to investigate the factors, economic, political, and others that determined the high rate of adoption of this fuel. A central objective of this research was to identify lessons that could be useful to developed countries in their efforts to deploy alternative fuel vehicles. We find that fuel price regulation was a significant determinant of the adoption of compressed natural gas, while, contrary to expectations, government financing of refueling infrastructure was minimal. - Research Highlights: →The broad scale adoption of CNG for transportation in Argentina was initiated by a market demand for an effective fuel that was priced at a significantly lower level compared to the mainstream alternatives. →The Argentine played a marginal role in the development of refueling infrastructure. →The role of the government focused on sending clear signals to the marketplace and developing effective codes and standards. →Consumers willingness to switch to CNG increases as state of the economy deteriorates and disposable incomes decrease.

  14. 77 FR 37669 - Natural Gas Pipeline Company of America LLC; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2012-06-22

    ... continual repair and replacement of deteriorated parts, and are costly to test to assure continue compliance... Bruce H. Newsome, Vice President, Regulatory Products and Services, Natural Gas Pipeline Company of...-3070, or by email bruce[email protected] . This filing is available for review at the...

  15. 75 FR 9921 - San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation...

    Science.gov (United States)

    2010-03-04

    ... San Diego County and south-central Riverside County, California. We are requesting public comment on..., Escondido, CA 92025. 2. Kearney Mesa: San Diego County Water Authority, 4677 Overland Avenue, San Diego, CA... baccharis (Baccharis vanessae; threatened), Munz's onion (Allium munzii; endangered), Otay mesa mint...

  16. 77 FR 31004 - Southern Natural Gas Company; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2012-05-24

    ... a protest, the instant request shall be treated as an application for authorization pursuant to section 7 of the NGA. Persons who wish to comment only on the environmental review of this project should submit an original and two copies of their comments to the Secretary of the Commission. Environmental...

  17. 77 FR 58126 - Natural Gas Pipeline Company of America LLC; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2012-09-19

    ... request shall be treated as an application for authorization pursuant to section 7 of the NGA. Persons who wish to comment only on the environmental review of this project should submit an original and two copies of their comments to the Secretary of the Commission. Environmental commenters will be placed on...

  18. Development of a general thermodynamically consistent projection method for the Navier-Stokes equations and its application to compressible natural convection of real fluids

    Science.gov (United States)

    Cook, Charles R.

    The development of a general method for the direct solution of the Navier-Stokes equations, where no assumptions or modeling are required, with any equation of state, while maintaining thermodynamic equilibrium is the subject. This is accomplished through generalization of the Characteristic Based Split (CBS) method by removing isentropic assumptions and fully coupling the equation of state with the pressure and energy fields. The Modified CBS (MCBS) method is developed in rigor from first principles with the Navier-Stokes equations, where the equation of state is not required to be known or an analytical expression. Thermodynamic equilibrium, or thermodynamic consistency, where the pressure field from the equation of state, p(rho,T), is the same as the dynamic pressure field, is recovered through the implicit treatment of the temperature field during the solution of conservation of energy. Implicit treatment of both the pressure and temperature fields further enhances the MCBS method by permitting the integration over acoustic time scales if desired, achieving acoustic filtering without modification to the underlying governing equations. The MCBS as implemented in a new Finite Element Method (FEM) code is applied to the study of compressible natural convection, where the entirety of Navier-Stokes equations is expressed, with several equations of state. Validation of the MCBS method for incompressible Boussinesq, incompressible thermodynamic Boussinesq, and compressible low-Mach natural convection in a cavity and near wall compressible thermal expansion waves is achieved with exceptional accuracy with the single MCBS implementation. Further, the solution of natural convection in a cavity using RefProp for the equation of state as well as all thermodynamic and transport properties was successfully achieved with the same implementation, providing real fluid results. The case of natural convection in a cavity is further pushed into higher Rayleigh numbers where the

  19. A review of medical image compression methods - general characterization

    Energy Technology Data Exchange (ETDEWEB)

    Przelaskowski, A.; Kazubek, M.; Jamrogiewicz, T. [Politechnika Warszawska, Warsaw (Poland). Inst. Radioelektroniki

    1995-12-31

    The general view of the popular and often applied lossless and lossy compression techniques is presented. The lossless methods of either single image (intraframe methods ) or sequence of correlated images (interframe methods) are shortly characterized. Often used lossy methods are also introduced. A class of medical images has not specific features which could be used for improving the compression efficiency. The effective natural image lossless compression techniques are also efficient in the applications to medical image systems. The limit of achievable compression ratios is about 4. Techniques based on linear prediction methods are largely the most effective in reduction of spatial redundancy. An optimisation of prediction model allows to decrease bit rates of about 10% (over standard DPCM method). there is strong dependence of a conception of compression technique optimum conditions on specific application and realisation possibilities of the technique. (author). 35 refs, 2 fig.

  20. Compression-Based Compressed Sensing

    OpenAIRE

    Rezagah, Farideh Ebrahim; Jalali, Shirin; Erkip, Elza; Poor, H. Vincent

    2016-01-01

    Modern compression algorithms exploit complex structures that are present in signals to describe them very efficiently. On the other hand, the field of compressed sensing is built upon the observation that "structured" signals can be recovered from their under-determined set of linear projections. Currently, there is a large gap between the complexity of the structures studied in the area of compressed sensing and those employed by the state-of-the-art compression codes. Recent results in the...

  1. Compression embedding

    Science.gov (United States)

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  2. Development of a motor for use compressed biogas or natural gas; Desenvolvimento de um motor para uso de biogas e gas natural comprimidos

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Ricardo S. de [Mercedes Benz do Brasil S.A. (Brazil)

    1986-12-31

    The Mercedes Benz do Brazil S/A since 1983 has been testing the utilization of biogas in a bus equipped with otto cycle motor. The main preoccupation was develop a specific motor for gas and not adapted a alcohol or gasoline motor. Biogas was tested in Sao Paulo in a bus that go through 40000 Km and natural gas was tested in 3 bus in Natal city. The results obtained until now show the good possibilities of both alternatives. All the developments utilized adapted motors and the results will be transpose for a new motor that will be produced by Mercedes Benz do Brazil. 3 tabs., 18 figs.

  3. Analisis Komposit Serat kaca/Vinil ester terhadap Pembebanan Tekanan Internal untuk Aplikasi Tabung Gas Alam Terkompresi (Compressed Natural Gas (CNG Tipe IV

    Directory of Open Access Journals (Sweden)

    Risa Nurin Baiti

    2013-03-01

    Full Text Available Gas alam dalam bentuk Compressed Natural Gas (CNG memiliki tekanan 20 MPa. Komposit serat kaca/vinil ester memiliki potensi untuk dibentuk menjadi tabung CNG. Studi ini menggunakan metode analisa numerik untuk mengkaji kemampuan komposit dalam menerima beban tekanan internal. Faktor keamanan yang digunakan adalah 1,5 sehingga nilai tekanan internal yang diaplikasikan sebesar 35 MPa. Konstanta teknik yang diinputkan pada analisa numerik diperoleh melalui pengujian tarik. Jumlah lapisan dan arah serat dipilih sebagai variabel bebas. Analisa numerik tabung CNG dilakukan dengan pendekatan tubular menggunakan program MSC Nastran. Distribusi beban pada tabung menunjukkan sudut (+50 optimal untuk diaplikasikan. Konfigurasi sudut (+70,+25s memberikan hasil yang lebih optimum daripada penggunaan satu sudut. Jumlah lapisan minimum diperoleh dengan mengacu pada kriteria kegagalan laminat Hill. Komposit berada pada kondisi aman pada lapisan ke 180. Tetapi, komposit serat kaca/vinil ester dapat diaplikasikan pada pembuatan tabung liquified natural gas (LNG yang bertekanan 2MPa dengan 23 lapis lamina. Sehingga, material komposit serat kaca/vinil ester tidak disarankan untuk digunakan pada pembuatan tabung CNG

  4. Climate and environmental effects of electric vehicles versus compressed natural gas vehicles in China: a life-cycle analysis at provincial level.

    Science.gov (United States)

    Huo, Hong; Zhang, Qiang; Liu, Fei; He, Kebin

    2013-02-05

    Electric vehicles (EVs) and compressed natural gas vehicles (CNGVs), which are mainly coal-based and natural gas-based, are the two most widely proposed replacements of gasoline internal combustion engine vehicles (ICEVs) in P.R. China. We examine fuel-cycle emissions of greenhouse gases (GHGs), PM(2.5), PM(10), NO(x), and SO(2) of CNGVs and EVs relative to gasoline ICEVs and hybrids, by Chinese province. CNGVs can currently reduce emissions of GHGs, PM(10), PM(2,5), NO(x), and SO(2) by approximately 6%, 7%, 20%, 18% and 22%, respectively. EVs can reduce GHG emissions by 20%, but increase PM(10), PM(2.5), NO(x), and SO(2) emissions by approximately 360%, 250%, 120%, and 370%, respectively. Nevertheless, results vary significantly by province. Regarding their contribution to national emissions, PM increases from EVs are unimportant, because light-duty passenger vehicles contribute very little to overall PM emissions nationwide (≤0.05%); however, their NO(x) and SO(2) increases are important. Since China is striving to reduce power plant emissions, EVs are expected to have equivalent or even lower SO(2) and NO(x) emissions relative to ICEVs in the future (2030). Before then, however, EVs should be developed according to the cleanness of regional power mixes. This would lower their SO(2) and NO(x) emissions and earn more GHG reduction credits.

  5. Author Details

    African Journals Online (AJOL)

    Khoodaruth, A. Vol 20 (2014) - Articles An Investigation on the Performance of a Compression Engine when fuelled with Blends of Coconut Oil and Diesel Abstract PDF. ISSN: 1694-0342. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  6. Author Details

    African Journals Online (AJOL)

    Omokanye, KO. Vol 21, No 2 (2014) - Articles Primary thoracic epidural lymphoma: A rare cause of spinal cord compression. Abstract. ISSN: 1117-4153. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of ...

  7. Author Details

    African Journals Online (AJOL)

    Baraka, N. Vol 16 (2003) - Articles A lossless image compression algorithm using variable block size segmentation. Abstract. ISSN: 1111-0902. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

  8. Author Details

    African Journals Online (AJOL)

    Bhatia, PG. Vol 12, No 2 (2009) - Articles Effects of Native and Pregelatinised Fonio starches on compression, mechanical and release properties of paracetamol tablet formulations. Abstract PDF. ISSN: 1026-552X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

  9. Author Details

    African Journals Online (AJOL)

    Muazu, J. Vol 12, No 2 (2009) - Articles Effects of Native and Pregelatinised Fonio starches on compression, mechanical and release properties of paracetamol tablet formulations. Abstract PDF. ISSN: 1026-552X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

  10. Author Details

    African Journals Online (AJOL)

    Koriko, OK. Vol 18 (2011) - Articles Variable Thermal Conductivity on Compressible Boundary Layer Flow over a Circular Cylinder Abstract. ISSN: 1116-4336. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions ...

  11. Author Details

    African Journals Online (AJOL)

    -mortar masonry under compression. Abstract. ISSN: 0855-2215. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

  12. Toxicity and mutagenicity of exhaust from compressed natural gas: Could this be a clean solution for megacities with mixed-traffic conditions?

    Science.gov (United States)

    Agarwal, Avinash K; Ateeq, Bushra; Gupta, Tarun; Singh, Akhilendra P; Pandey, Swaroop K; Sharma, Nikhil; Agarwal, Rashmi A; Gupta, Neeraj K; Sharma, Hemant; Jain, Ayush; Shukla, Pravesh C

    2018-04-20

    Despite intensive research carried out on particulates, correlation between engine-out particulate emissions and adverse health effects is not well understood yet. Particulate emissions hold enormous significance for mega-cities like Delhi that have immense traffic diversity. Entire public transportation system involving taxis, three-wheelers, and buses has been switched from conventional liquid fuels to compressed natural gas (CNG) in the Mega-city of Delhi. In this study, the particulate characterization was carried out on variety of engines including three diesel engines complying with Euro-II, Euro-III and Euro-IV emission norms, one Euro-II gasoline engine and one Euro-IV CNG engine. Physical, chemical and biological characterizations of particulates were performed to assess the particulate toxicity. The mutagenic potential of particulate samples was investigated at different concentrations using two different Salmonella strains, TA98 and TA100 in presence and absence of liver S9 metabolic enzyme fraction. Particulates emitted from diesel and gasoline engines showed higher mutagenicity, while those from CNG engine showed negligible mutagenicity compared to other test fuels and engine configurations. Polycyclic aromatic hydrocarbons (PAHs) adsorbed onto CNG engine particulates were also relatively fewer compared to those from equivalent diesel and gasoline engines. Taken together, our findings indicate that CNG is comparatively safer fuel compared to diesel and gasoline and can offer a cleaner transport energy solution for mega-cities with mixed-traffic conditions, especially in developing countries. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

    Directory of Open Access Journals (Sweden)

    Baofeng Yao

    2014-11-01

    Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

  14. Comportamento de um motor de ignição por compressão trabalhando com óleo Diesel e gás natural A dual fuel compression ignition engine performance, running with Diesel fuel and natural gas

    Directory of Open Access Journals (Sweden)

    José F. Schlosser

    2004-12-01

    Full Text Available A previsível escassez de petróleo aliada a uma consciência ecológica está levando pesquisadores a procurar novas fontes de energia e processos de combustão mais eficientes e menos poluentes. Entre os combustíveis menos poluentes está o gás natural, cujo consumo aumenta ano a ano. Os motores de combustão interna são transformadores de energia que têm baixa eficiência de conversão. Este trabalho avaliou um motor Diesel, bicombustível, movido a Diesel e gás natural. Nesse motor, a energia provém, basicamente, da combustão do gás natural. O Diesel tem a função de produzir o início da combustão do gás, que é o combustível principal. Assim, haverá uma substituição parcial de óleo Diesel por gás natural, aumentando o rendimento da combustão. Inicialmente, foi feito um ensaio-testemunha, somente com óleo Diesel e após foram feitos ensaios, com três repetições, para variadas proporções de óleo Diesel, gás natural e ângulos de avanço da injeção. O melhor desempenho foi obtido para 22% de óleo Diesel em relação ao máximo débito da bomba injetora e 13 L min-1 de gás natural com ângulo de avanço de injeção original (21º. Nesse caso, a potência média aumentou 14%, e o consumo específico (medido em valores monetários diminuiu 46% em relação ao ensaio-testemunha.The foresight of a petroleum shortage and an ecological conscience is moving scientists to look for new sources of energy and to develop more efficient combustion processes and reduced emissions. Natural gas is a reduced emission fuel, whose consumption increases every year. The present work evaluates a dual fuel compression ignition engine. The major portion of the fuel burned is natural gas. The Diesel fuel acts as combustion starter, which ignites under the compression heat. Diesel fuel is used only as an ignition source. The partial substitution of Diesel fuel by natural gas increases the combustion efficiency and achieves significant

  15. Effect of Hydrogen and Hydrogen Enriched Compressed Natural Gas Induction on the Performance of Rubber Seed Oil Methy Ester Fuelled Common Rail Direct Injection (CRDi Dual Fuel Engines

    Directory of Open Access Journals (Sweden)

    Mallikarjun Bhovi

    2017-06-01

    Full Text Available Renewable fuels are in biodegradable nature and they tender good energy security and foreign exchange savings. In addition they address environmental concerns and socio-economic issues. The present work presents the experimental investigations carried out on the utilization of such renewable fuel combinations for diesel engine applications. For this a single-cylinder four-stroke water cooled direct injection (DI compression ignition (CI engine provided with CMFIS (Conventional Mechanical Fuel Injection System was rightfully converted to operate with CRDi injection systems enabling high pressure injection of Rubber seed oil methyl ester (RuOME in the dual fuel mode with induction of varied gas flow rates of hydrogen and hydrogen enriched CNG (HCNG gas combinations. Experimental investigations showed a considerable improvement in dual fuel engine performance with acceptable brake thermal efficiency and reduced emissions of smoke, hydrocarbon (HC, carbon monoxide (CO and slightly increased nitric oxide (NOx emission levels for increased hydrogen and HCNG flow rates. Further CRDi facilitated dual fuel engine showed improved engine performance compared to CMFIS as the former enabled high pressure (900 bar injection of the RuOME and closer to TDC (Top Dead Centre as well. Combustion parameters such as ignition delay, combustion duration, pressure-crank angle and heat release rates were analyzed and compared with baseline data generated. Combustion analysis showed that the rapid rate of burning of hydrogen and HCNG along with air mixtures increased due to presence of hydrogen in total and in partial combination with CNG which further resulted into higher cylinder pressures and energy release rates. However, sustained research that can provide feasible engine technology operating on such fuels in dual fuel operation can pave the way for continued fossil fuel usage.

  16. Compressive beamforming

    DEFF Research Database (Denmark)

    Xenaki, Angeliki; Mosegaard, Klaus

    2014-01-01

    Sound source localization with sensor arrays involves the estimation of the direction-of-arrival (DOA) from a limited number of observations. Compressive sensing (CS) solves such underdetermined problems achieving sparsity, thus improved resolution, and can be solved efficiently with convex...

  17. 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)

  18. Overview of the Safety Issues Associated with the Compressed Natural Gas Fuel System and Electric Drive System in a Heavy Hybrid Electric Vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.C.

    2002-11-14

    This report evaluates the hazards that are unique to a compressed-natural-gas (CNG)-fueled heavy hybrid electric vehicle (HEV) design compared with a conventional heavy vehicle. The unique design features of the heavy HEV are the CNG fuel system for the internal-combustion engine (ICE) and the electric drive system. This report addresses safety issues with the CNG fuel system and the electric drive system. Vehicles on U. S. highways have been propelled by ICEs for several decades. Heavy-duty vehicles have typically been fueled by diesel fuel, and light-duty vehicles have been fueled by gasoline. The hazards and risks posed by ICE vehicles are well understood and have been generally accepted by the public. The economy, durability, and safety of ICE vehicles have established a standard for other types of vehicles. Heavy-duty (i.e., heavy) HEVs have recently been introduced to U. S. roadways, and the hazards posed by these heavy HEVs can be compared with the hazards posed by ICE vehicles. The benefits of heavy HEV technology are based on their potential for reduced fuel consumption and lower exhaust emissions, while the disadvantages are the higher acquisition cost and the expected higher maintenance costs (i.e., battery packs). The heavy HEV is more suited for an urban drive cycle with stop-and-go driving conditions than for steady expressway speeds. With increasing highway congestion and the resulting increased idle time, the fuel consumption advantage for heavy HEVs (compared with conventional heavy vehicles) is enhanced by the HEVs' ability to shut down. Any increase in fuel cost obviously improves the economics of a heavy HEV. The propulsion system for a heavy HEV is more complex than the propulsion system for a conventional heavy vehicle. The heavy HEV evaluated in this study has in effect two propulsion systems: an ICE fueled by CNG and an electric drive system with additional complexity and failure modes. This additional equipment will result in a less

  19. 77 FR 72840 - CE FLNG, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced...

    Science.gov (United States)

    2012-12-06

    ..., DOE/FE issued Order No. 3193, granting long-term multi-contract authorization to export LNG by vessel... Application In the instant application, CE FLNG seeks long-term, multi-contract authorization to export up to... is not prohibited by United States law or policy. CE FLNG requests that such long-term authorization...

  20. Emissions of toxic pollutants from compressed natural gas and low sulfur diesel-fueled heavy-duty transit buses tested over multiple driving cycles.

    Science.gov (United States)

    Kado, Norman Y; Okamoto, Robert A; Kuzmicky, Paul A; Kobayashi, Reiko; Ayala, Alberto; Gebel, Michael E; Rieger, Paul L; Maddox, Christine; Zafonte, Leo

    2005-10-01

    The number of heavy-duty vehicles using alternative fuels such as compressed natural gas (CNG) and new low-sulfur diesel fuel formulations and equipped with after-treatment devices are projected to increase. However, few peer-reviewed studies have characterized the emissions of particulate matter (PM) and other toxic compounds from these vehicles. In this study, chemical and biological analyses were used to characterize the identifiable toxic air pollutants emitted from both CNG and low-sulfur-diesel-fueled heavy-duty transit buses tested on a chassis dynamometer over three transient driving cycles and a steady-state cruise condition. The CNG bus had no after-treatment, and the diesel bus was tested first equipped with an oxidation catalyst (OC) and then with a catalyzed diesel particulate filter (DPF). Emissions were analyzed for PM, volatile organic compounds (VOCs; determined on-site), polycyclic aromatic hydrocarbons (PAHs), and mutagenic activity. The 2000 model year CNG-fueled vehicle had the highest emissions of 1,3-butadiene, benzene, and carbonyls (e.g., formaldehyde) of the three vehicle configurations tested in this study. The 1998 model year diesel bus equipped with an OC and fueled with low-sulfur diesel had the highest emission rates of PM and PAHs. The highest specific mutagenic activities (revertants/microg PM, or potency) and the highest mutagen emission rates (revertants/mi) were from the CNG bus in strain TA98 tested over the New York Bus (NYB) driving cycle. The 1998 model year diesel bus with DPF had the lowest VOCs, PAH, and mutagenic activity emission. In general, the NYB driving cycle had the highest emission rates (g/mi), and the Urban Dynamometer Driving Schedule (UDDS) had the lowest emission rates for all toxics tested over the three transient test cycles investigated. Also, transient emissions were, in general, higher than steady-state emissions. The emissions of toxic compounds from an in-use CNG transit bus (without an oxidation

  1. Speech Compression

    Directory of Open Access Journals (Sweden)

    Jerry D. Gibson

    2016-06-01

    Full Text Available Speech compression is a key technology underlying digital cellular communications, VoIP, voicemail, and voice response systems. We trace the evolution of speech coding based on the linear prediction model, highlight the key milestones in speech coding, and outline the structures of the most important speech coding standards. Current challenges, future research directions, fundamental limits on performance, and the critical open problem of speech coding for emergency first responders are all discussed.

  2. 78 FR 75337 - Eos LNG LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced...

    Science.gov (United States)

    2013-12-11

    ... hub in North America, the Henry Hub, is located in southern Louisiana, and the Houston Ship Channel..., Korea, and Taiwan, are dependent upon LNG imports for their natural gas supplies. Eos states that while... natural gas supply, U.S. energy security, and any other issues, including the impact on the U.S. economy...

  3. Nonlinear Frequency Compression

    Science.gov (United States)

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  4. Toxicological properties of emission particles from heavy duty engines powered by conventional and bio-based diesel fuels and compressed natural gas

    Directory of Open Access Journals (Sweden)

    Jalava Pasi I

    2012-09-01

    Full Text Available Abstract Background One of the major areas for increasing the use of renewable energy is in traffic fuels e.g. bio-based fuels in diesel engines especially in commuter traffic. Exhaust emissions from fossil diesel fuelled engines are known to cause adverse effects on human health, but there is very limited information available on how the new renewable fuels may change the harmfulness of the emissions, especially particles (PM. We evaluated the PM emissions from a heavy-duty EURO IV diesel engine powered by three different fuels; the toxicological properties of the emitted PM were investigated. Conventional diesel fuel (EN590 and two biodiesels were used − rapeseed methyl ester (RME, EN14214 and hydrotreated vegetable oil (HVO either as such or as 30% blends with EN590. EN590 and 100% HVO were also operated with or without an oxidative catalyst (DOC + POC. A bus powered by compressed natural gas (CNG was included for comparison with the liquid fuels. However, the results from CNG powered bus cannot be directly compared to the other situations in this study. Results High volume PM samples were collected on PTFE filters from a constant volume dilution tunnel. The PM mass emission with HVO was smaller and with RME larger than that with EN590, but both biofuels produced lower PAH contents in emission PM. The DOC + POC catalyst greatly reduced the PM emission and PAH content in PM with both HVO and EN590. Dose-dependent TNFα and MIP-2 responses to all PM samples were mostly at the low or moderate level after 24-hour exposure in a mouse macrophage cell line RAW 264.7. Emission PM from situations with the smallest mass emissions (HVO + cat and CNG displayed the strongest potency in MIP-2 production. The catalyst slightly decreased the PM-induced TNFα responses and somewhat increased the MIP-2 responses with HVO fuel. Emission PM with EN590 and with 30% HVO blended in EN590 induced the strongest genotoxic responses, which were

  5. Toxicological properties of emission particles from heavy duty engines powered by conventional and bio-based diesel fuels and compressed natural gas

    Science.gov (United States)

    2012-01-01

    Background One of the major areas for increasing the use of renewable energy is in traffic fuels e.g. bio-based fuels in diesel engines especially in commuter traffic. Exhaust emissions from fossil diesel fuelled engines are known to cause adverse effects on human health, but there is very limited information available on how the new renewable fuels may change the harmfulness of the emissions, especially particles (PM). We evaluated the PM emissions from a heavy-duty EURO IV diesel engine powered by three different fuels; the toxicological properties of the emitted PM were investigated. Conventional diesel fuel (EN590) and two biodiesels were used − rapeseed methyl ester (RME, EN14214) and hydrotreated vegetable oil (HVO) either as such or as 30% blends with EN590. EN590 and 100% HVO were also operated with or without an oxidative catalyst (DOC + POC). A bus powered by compressed natural gas (CNG) was included for comparison with the liquid fuels. However, the results from CNG powered bus cannot be directly compared to the other situations in this study. Results High volume PM samples were collected on PTFE filters from a constant volume dilution tunnel. The PM mass emission with HVO was smaller and with RME larger than that with EN590, but both biofuels produced lower PAH contents in emission PM. The DOC + POC catalyst greatly reduced the PM emission and PAH content in PM with both HVO and EN590. Dose-dependent TNFα and MIP-2 responses to all PM samples were mostly at the low or moderate level after 24-hour exposure in a mouse macrophage cell line RAW 264.7. Emission PM from situations with the smallest mass emissions (HVO + cat and CNG) displayed the strongest potency in MIP-2 production. The catalyst slightly decreased the PM-induced TNFα responses and somewhat increased the MIP-2 responses with HVO fuel. Emission PM with EN590 and with 30% HVO blended in EN590 induced the strongest genotoxic responses, which were significantly greater than

  6. Toxicological properties of emission particles from heavy duty engines powered by conventional and bio-based diesel fuels and compressed natural gas.

    Science.gov (United States)

    Jalava, Pasi I; Aakko-Saksa, Päivi; Murtonen, Timo; Happo, Mikko S; Markkanen, Ari; Yli-Pirilä, Pasi; Hakulinen, Pasi; Hillamo, Risto; Mäki-Paakkanen, Jorma; Salonen, Raimo O; Jokiniemi, Jorma; Hirvonen, Maija-Riitta

    2012-09-29

    One of the major areas for increasing the use of renewable energy is in traffic fuels e.g. bio-based fuels in diesel engines especially in commuter traffic. Exhaust emissions from fossil diesel fuelled engines are known to cause adverse effects on human health, but there is very limited information available on how the new renewable fuels may change the harmfulness of the emissions, especially particles (PM). We evaluated the PM emissions from a heavy-duty EURO IV diesel engine powered by three different fuels; the toxicological properties of the emitted PM were investigated. Conventional diesel fuel (EN590) and two biodiesels were used - rapeseed methyl ester (RME, EN14214) and hydrotreated vegetable oil (HVO) either as such or as 30% blends with EN590. EN590 and 100% HVO were also operated with or without an oxidative catalyst (DOC + POC). A bus powered by compressed natural gas (CNG) was included for comparison with the liquid fuels. However, the results from CNG powered bus cannot be directly compared to the other situations in this study. High volume PM samples were collected on PTFE filters from a constant volume dilution tunnel. The PM mass emission with HVO was smaller and with RME larger than that with EN590, but both biofuels produced lower PAH contents in emission PM. The DOC + POC catalyst greatly reduced the PM emission and PAH content in PM with both HVO and EN590. Dose-dependent TNFα and MIP-2 responses to all PM samples were mostly at the low or moderate level after 24-hour exposure in a mouse macrophage cell line RAW 264.7. Emission PM from situations with the smallest mass emissions (HVO + cat and CNG) displayed the strongest potency in MIP-2 production. The catalyst slightly decreased the PM-induced TNFα responses and somewhat increased the MIP-2 responses with HVO fuel. Emission PM with EN590 and with 30% HVO blended in EN590 induced the strongest genotoxic responses, which were significantly greater than those with EN590

  7. 77 FR 72837 - Golden Pass Products LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas...

    Science.gov (United States)

    2012-12-06

    ... Florida Gas Transmission Company, LLC; Golden Triangle Storage, Inc.; Natural Gas Pipeline Company of... DEPARTMENT OF ENERGY [FE Docket No. 12-156-LNG] Golden Pass Products LLC; Application for Long... notice of receipt of an application (Application) filed on October 26, 2012, by Golden Pass Products LLC...

  8. 75 FR 62510 - Chevron U.S.A. Inc.; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-10-12

    ... domestic and world markets for natural gas and LNG. More specifically, Chevron asserts it desires the... sale in domestic markets. Chevron states that it would base any decision related to the sale of... when market conditions dictate that the LNG be used to meet domestic needs. Public Interest...

  9. 78 FR 21934 - El Paso Natural Gas Company, L.L.C.; Notice of Request Under Blanket Authorization

    Science.gov (United States)

    2013-04-12

    ... for filing a protest, the instant request shall be treated as an application for authorization pursuant to Section 7 of the NGA. Persons who wish to comment only on the environmental review of this.... Environmental commenter's will be placed on the Commission's environmental mailing list, will receive copies of...

  10. 76 FR 33746 - Freeport LNG Development, L.P.; Application for Blanket Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2011-06-09

    ... imported into the United States from foreign sources on a short-term or spot market basis. The LNG would be... amended, an LNG export from the United States to a foreign country must be authorized unless ``the... import LNG via ocean-going carrier, and with which trade is not prohibited by U.S. law or policy...

  11. Mammography image compression using Wavelet

    International Nuclear Information System (INIS)

    Azuhar Ripin; Md Saion Salikin; Wan Hazlinda Ismail; Asmaliza Hashim; Norriza Md Isa

    2004-01-01

    Image compression plays an important role in many applications like medical imaging, televideo conferencing, remote sensing, document and facsimile transmission, which depend on the efficient manipulation, storage, and transmission of binary, gray scale, or color images. In Medical imaging application such Picture Archiving and Communication System (PACs), the image size or image stream size is too large and requires a large amount of storage space or high bandwidth for communication. Image compression techniques are divided into two categories namely lossy and lossless data compression. Wavelet method used in this project is a lossless compression method. In this method, the exact original mammography image data can be recovered. In this project, mammography images are digitized by using Vider Sierra Plus digitizer. The digitized images are compressed by using this wavelet image compression technique. Interactive Data Language (IDLs) numerical and visualization software is used to perform all of the calculations, to generate and display all of the compressed images. Results of this project are presented in this paper. (Author)

  12. Phonocardiogram signal compression using sound repetition and vector quantization.

    Science.gov (United States)

    Tang, Hong; Zhang, Jinhui; Sun, Jian; Qiu, Tianshuang; Park, Yongwan

    2016-04-01

    A phonocardiogram (PCG) signal can be recorded for long-term heart monitoring. A huge amount of data is produced if the time of a recording is as long as days or weeks. It is necessary to compress the PCG signal to reduce storage space in a record and play system. In another situation, the PCG signal is transmitted to a remote health care center for automatic analysis in telemedicine. Compression of the PCG signal in that situation is necessary as a means for reducing the amount of data to be transmitted. Since heart beats are of a cyclical nature, compression can make use of the similarities in adjacent cycles by eliminating repetitive elements as redundant. This study proposes a new compression method that takes advantage of these repetitions. Data compression proceeds in two stages, a training stage followed by the compression as such. In the training stage, a section of the PCG signal is selected and its sounds and murmurs (if any) decomposed into time-frequency components. Basic components are extracted from these by clustering and collected to form a dictionary that allows the generative reconstruction and retrieval of any heart sound or murmur. In the compression stage, the heart sounds and murmurs are reconstructed from the basic components stored in the dictionary. Compression is made possible because only the times of occurrence and the dictionary indices of the basic components need to be stored, which greatly reduces the number of bits required to represent heart sounds and murmurs. The residual that cannot be reconstructed in this manner appears as a random sequence and is further compressed by vector quantization. What we propose are quick search parameters for this vector quantization. For normal PCG signals the compression ratio ranges from 20 to 149, for signals with median murmurs it ranges from 14 to 35, and for those with heavy murmurs, from 8 to 20, subject to a degree of distortion of ~5% (in percent root-mean-square difference) and a sampling

  13. Evaluation of mammogram compression efficiency

    International Nuclear Information System (INIS)

    Przelaskowski, A.; Surowski, P.; Kukula, A.

    2005-01-01

    quality of 0.6 bpp and 0.1 bpp reconstructions was decreased. The compression performance of the most effective reversible coders is rather unsatisfactory. The subjective rating with the diagnostic criteria of image quality was more sensitive to distortions caused by lossy compression compared with the pathology detection test. The observers constituted 14:1 as the accepted ratio of lossy wavelet compression for test mammograms. This is significantly higher than the mean ratio of 2:1 achieved with lossless methods. (author)

  14. Radiologic image compression -- A review

    International Nuclear Information System (INIS)

    Wong, S.; Huang, H.K.; Zaremba, L.; Gooden, D.

    1995-01-01

    The objective of radiologic image compression is to reduce the data volume of and to achieve a lot bit rate in the digital representation of radiologic images without perceived loss of image quality. However, the demand for transmission bandwidth and storage space in the digital radiology environment, especially picture archiving and communication systems (PACS) and teleradiology, and the proliferating use of various imaging modalities, such as magnetic resonance imaging, computed tomography, ultrasonography, nuclear medicine, computed radiography, and digital subtraction angiography, continue to outstrip the capabilities of existing technologies. The availability of lossy coding techniques for clinical diagnoses further implicates many complex legal and regulatory issues. This paper reviews the recent progress of lossless and lossy radiologic image compression and presents the legal challenges of using lossy compression of medical records. To do so, the authors first describe the fundamental concepts of radiologic imaging and digitization. Then, the authors examine current compression technology in the field of medical imaging and discuss important regulatory policies and legal questions facing the use of compression in this field. The authors conclude with a summary of future challenges and research directions. 170 refs

  15. Compression limits in cascaded quadratic soliton compression

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Krolikowski, Wieslaw

    2008-01-01

    Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency.......Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency....

  16. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  17. Fruitflow®: the first European Food Safety Authority-approved natural cardio-protective functional ingredient.

    Science.gov (United States)

    O'Kennedy, Niamh; Raederstorff, Daniel; Duttaroy, Asim K

    2017-03-01

    Hyperactive platelets, in addition to their roles in thrombosis, are also important mediators of atherogenesis. Antiplatelet drugs are not suitable for use where risk of a cardiovascular event is relatively low. It is therefore important to find alternative safe antiplatelet inhibitors for the vulnerable population who has hyperactive platelets in order to reduce the risk of cardiovascular disease. Potent antiplatelet factors were identified in water-soluble tomato extract (Fruitflow ® ), which significantly inhibited platelet aggregation. Human volunteer studies demonstrated the potency and bioavailability of active compounds in Fruitflow ® . Fruitflow ® became the first product in Europe to obtain an approved, proprietary health claim under Article 13(5) of the European Health Claims Regulation 1924/2006 on nutrition and health claims made on foods. Fruitflow ® is now commercially available in different countries worldwide. In addition to its reduction in platelet reactivity, Fruitflow ® contains anti-angiotensin-converting enzyme and anti-inflammatory factors, making it an effective and natural cardio-protective functional food.

  18. Author Details

    African Journals Online (AJOL)

    de Freitas, Stephanie. Vol 15, No 2 (2015) - Articles Book Review: The nature of intractable conflict: Resolution in the twenty-first century. Abstract PDF. ISSN: 1562-6997. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

  19. Author Details

    African Journals Online (AJOL)

    natural conditions in speckled mousebirds: the role of communal roosting. Abstract. ISSN: 2224-073X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  20. Author Details

    African Journals Online (AJOL)

    Nia, R. Vol 3, No 3 (2003) - Articles A potential natural environmental-friendly insecticide Citrus sinensis vs Citrus aurantium. Details PDF · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact ...

  1. Author Details

    African Journals Online (AJOL)

    Amao, A.O. Vol 4, No 1 (2009) - Articles Natural foods and feeding habits of the African honey bee Apis mellifera adansonii Latrielle (1804) in Zaria, northern Nigeria Abstract PDF. ISSN: 1597-6343. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  2. Author Details

    African Journals Online (AJOL)

    Ansari, M. Vol 3, No 3 (2014) - Articles Evaluating Visual Quality of Natural Landscapes to Achieve Sustainable Development: A Case Study of Margoon Waterfall Protected Area, Iran Abstract PDF. ISSN: 2305-3372. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

  3. Author Details

    African Journals Online (AJOL)

    Parize, AL. Vol 7, No 17 (2008) - Articles Microencapsulation of the natural urucum pigment with chitosan by spray drying in different solvents. Abstract PDF. ISSN: 1684-5315. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    African Journals Online (AJOL)

    Gorgoso-Varela, JJ. Vol 7, No 2 (2015) - Articles Comparison of estimation methods for fitting weibull distribution to the natural stand of Oluwa Forest Reserve, Ondo State, Nigeria Abstract PDF. ISSN: 2141-1778. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

  5. Author Details

    African Journals Online (AJOL)

    Ogana, FN. Vol 7, No 2 (2015) - Articles Comparison of estimation methods for fitting weibull distribution to the natural stand of Oluwa Forest Reserve, Ondo State, Nigeria Abstract PDF. ISSN: 2141-1778. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

  6. Author Details

    African Journals Online (AJOL)

    Taha, Abdel-Hady M. Vol 13, No 3 (2017) - Articles Can a foreign body migrate against natural body barriers? Abstract PDF. ISSN: 1687-4137. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

  7. Author Details

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    Ibrahim, A. Vol 19, No 1 (2011) - Articles Artificial and Natural Radioactivity Measurements and Radiation Dose Assessment in the Vicinity of Ghana Nuclear Research Reactor-1 (GHARR-1) Abstract PDF. ISSN: 0855-4307. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  8. Author Details

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    Motsamai, O.S. Vol 16, No 2 (2007) - Articles Thermal analysis of a kitchen natural ventilation system with computational fluid dynamics: a case study. Abstract. ISSN: 1019-1593. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

  9. Author Details

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    Onu, RN. Vol 14, No 2 (2011) - Articles Evaluation of bioadhesive properties of natural and modified banana starches. Abstract PDF. ISSN: 1026-552X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

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    Ghiasi, Mahdieh. Vol 11, No 2 (2016) - Articles The assessment of natural scaffolds ability in chondrogenic differentiation of human adipose-derived mesenchymal stem cells. Abstract PDF. ISSN: 1694-0423. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Kanu, EU. Vol 3, No 1 (2012) - Articles Graphic Design and the Changing Nature of Communication Media: A Historical Perspective and Implications for Design Training Abstract. ISSN: 2141-4343. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Simons, LE. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Buckley, GA. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Kirsten, GJC. Vol 35, No 3 (2015) - Articles The nature of workplace bullying experienced by teachers and the biopsychosocial health effects. Abstract PDF. ISSN: 2076-3433. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

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    Umeh, EDN. Vol 3, No 2 (2005) - Articles Management of african rice gall midge Orseolia oryzivora Harris and Gagné with reference to time planting and natural enemies in southeastern Nigeria Abstract. ISSN: 1597-0906. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Njukeng, N.J. Vol 15, No 1-2 (2010) - Articles Relationships between physiological parameters of latex and technological properties of processed natural rubber. Abstract. ISSN: 0855-2215. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Adewunmi, YA. Vol 8, No 2 (2015) - Articles Comparison of the Nature and Strategic features of Facilities Management and Other Building Support Practices in Lagos Abstract PDF. ISSN: 1596-6035. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Oyekan, AO. Vol 2, No 1 (2010) - Articles Human Nature and Social Order: A Comparative Critique of Hobbes and Locke Abstract PDF. ISSN: 2076-7714. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of ...

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    Afisi, OT. Vol 1, No 2 (2009) - Articles Human Nature in Marxism-Leninism and African Socialism Abstract PDF. ISSN: 2076-7714. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    Lawi, YQ. Vol 12, No 1 (2012) - Articles SNV (Tanzania) - A Window for Viewing the Changing Nature of Development Aid to Tanzania (1960s – 2005) Abstract. ISSN: 2591 6831. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

  1. Author Details

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    Carrano, MT. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Burney, D. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Jungers, WL. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Nodrehaug, Je. Vol 25, No 2 (2011) - Articles The Multifactorial Nature of Thromboembolic and Bleeding Complications among Patients with Mechanical Heart Valves in Tanzania Abstract. ISSN: 0856-0714. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Okeke, AI. Vol 31 (2000) - Articles Natural regeneration of some mangrove species in a Mealeuca Leucodendron plantation at Abel-Kiri, Nigeria Abstract. ISSN: 0300-368X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

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    Olabode, OA. Vol 2, No 2 (2006) - Articles Listeria monocytogenes: the nature, public health aspects and retrospective situations of an emerging infectious pathogen in Nigerian Abstract. ISSN: 0794-4721. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    Forster, CA. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Chatrath, PS. Vol 1, No 1 (2006) - Articles Preserving Madagascar's Natural Heritage: The Importance of Keeping the Island's Vertebrate Fossils in the Public Domain Abstract PDF. ISSN: 1662-2510. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Kabonga, RM. Vol 37, No 4 (2010) - Articles Factors influencing utilization of Natural Family Planning among Child Bearing Women in Chilonga Northern Province Zambia Abstract PDF. ISSN: 0047-651X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    Eyal, P. Vol 23, No 2 (2017) - Articles An endometrial histomorphometric study of CD56+ natural killer cells in women with unexplained infertility. Abstract PDF. ISSN: 2305-8862. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Allwood, Jens. Vol 36, No 1 (2016) - Articles An exploration of the nature, functions and subcategories of the discourse functional category, Interactive, in spoken Xhosa Abstract. ISSN: 0257-2117. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Nonis, M. Vol 35, No 1 (2005) - Articles Simulated natural lighting and constant 14-hour photoperiods for broiler breeders during the rearing period, and interactions of lighting with body weight. Abstract PDF. ISSN: 2221-4062. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Bolatito, L-A. Vol 9 (2012) - Articles The Natural Law Theory of Morality and the Homosexuality Debate in an African Culture Abstract PDF. ISSN: 1597-474X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions ...

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    El-S Gaber, F. Vol 35, No 2 (2011) - Articles Inhibition of Listeria monocytogenes and Yersinia enterocolitica in minced beef by naturally occurring antimicrobial. Abstract. ISSN: 0256-5161. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Tsvere, M. Vol 1, No 1 (2010) - Articles Exploring the Nature and Practice of Career Guidance in Secondary Schools in Mashonaland West Province of Zimbabwe. Abstract. ISSN: 2079-8997. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  16. Compression for preventing recurrence of venous ulcers.

    Science.gov (United States)

    Nelson, E Andrea; Bell-Syer, Sally E M

    2014-09-09

    Up to 1% of adults will have a leg ulcer at some time. The majority of leg ulcers are venous in origin and are caused by high pressure in the veins due to blockage or weakness of the valves in the veins of the leg. Prevention and treatment of venous ulcers is aimed at reducing the pressure either by removing/repairing the veins, or by applying compression bandages/stockings to reduce the pressure in the veins.The majority of venous ulcers heal with compression bandages, however ulcers frequently recur. Clinical guidelines therefore recommend that people continue to wear compression, usually in the form of hosiery (tights, stockings, socks) after their ulcer heals, to prevent recurrence. To assess the effects of compression (socks, stockings, tights, bandages) in preventing the recurrence of venous ulcers. If compression does prevent ulceration compared with no compression, then to identify whether there is evidence to recommend particular levels of compression (high, medium or low, for example), types of compression, or brands of compression to prevent ulcer recurrence after healing. For this second update we searched The Cochrane Wounds Group Specialised Register (searched 4 September 2014) which includes the results of regular searches of MEDLINE, EMBASE and CINAHL; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 8). Randomised controlled trials (RCTs)evaluating compression bandages or hosiery for preventing the recurrence of venous ulcers. Two review authors undertook data extraction and risk of bias assessment independently. Four trials (979 participants) were eligible for inclusion in this review. One trial in patients with recently healed venous ulcers (n = 153) compared recurrence rates with and without compression and found that compression significantly reduced ulcer recurrence at six months (Risk ratio (RR) 0.46, 95% CI 0.27 to 0.76).Two trials compared high-compression hosiery (equivalent to UK class 3) with

  17. Natural gas for vehicles

    International Nuclear Information System (INIS)

    Chauveron, S. de

    1996-01-01

    This article presents compressed natural gas for vehicles (CNG), which can provide considerable advantages both as an alternative fuel and as a clean fuel. These assets are not only economic but also technical. The first part deals with what is at stake in developing natural gas as a motor fuel. The first countries to use CNG were those with natural gas resources in their subsoil. Today, with a large number of countries having to cope with growing concern about increasing urban pollution, natural gas is also seen as a clean fuel that can help cut vehicle pollutant emissions dramatically. In the second part a brief technical descriptions is given of CNG stations and vehicles, with the aim of acquainting the reader with some of CNG's specific technical features as compared to gasoline and diesel oil. Here CNG technologies are seen to be very close to the more conventional ones. (author)

  18. Preliminary technical and economic viability for the implantation of fluvial transport of CNG (Compressed Natural Gas) for barges in Amazon Region; Avaliacao preliminar de viabilidade tecnico-economica para implantacao de transporte fluvial de GNC (Gas Natual Comprimido) por barcacas na Regiao Amazonica

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Marcos C.C. de; Porto, Paulo L. Lemgruber [Interocean Engenharia e Ship Management, Rio de janeiro, RJ (Brazil); Cunha, Rafael H. da [Metro Rio, RJ (Brazil); Garcia, Rafael M. [Pic Brasil (Brazil); Almeida, Marco A.R. de [Universidade Gama Filho (UGF), Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The isolated regions of the Amazon present difficulties for integration with the electrical system which is creating some economic problems due to the consequent costs of electric generation of subsidies as a function of the fossil fuel use as oils diesel and fuel. A viable option is the use of Natural Gas - NG that is Also available in the region. Its modal of transport possible in the Region North they are for gas-lines or barges. The Compressed Natural Gas transport is distinguished that - CNG for barges was still not tested operationally in Brazil. Soon, to develop a Preliminary Study of Viability Technician - Economic - SVTE for the implantation of fluvial transport of CNG between the cities of Coari and Manaus is basic, therefore it is created strategical alternative for the electric generation in this region. The electric sector, the characteristics of the NG and the transport in this region had been analyzed to support to the work. The gas line and the fluvial transport of CNG for barges in this region are not conflicting, and they in a complementary form can act. The SVTE presented a Liquid Present Value and Internal Tax of very attractive Return justifying its implantation. (author)

  19. Free compression tube. Applications

    Science.gov (United States)

    Rusu, Ioan

    2012-11-01

    During the flight of vehicles, their propulsion energy must overcome gravity, to ensure the displacement of air masses on vehicle trajectory, to cover both energy losses from the friction between a solid surface and the air and also the kinetic energy of reflected air masses due to the impact with the flying vehicle. The flight optimization by increasing speed and reducing fuel consumption has directed research in the aerodynamics field. The flying vehicles shapes obtained through studies in the wind tunnel provide the optimization of the impact with the air masses and the airflow along the vehicle. By energy balance studies for vehicles in flight, the author Ioan Rusu directed his research in reducing the energy lost at vehicle impact with air masses. In this respect as compared to classical solutions for building flight vehicles aerodynamic surfaces which reduce the impact and friction with air masses, Ioan Rusu has invented a device which he named free compression tube for rockets, registered with the State Office for Inventions and Trademarks of Romania, OSIM, deposit f 2011 0352. Mounted in front of flight vehicles it eliminates significantly the impact and friction of air masses with the vehicle solid. The air masses come into contact with the air inside the free compression tube and the air-solid friction is eliminated and replaced by air to air friction.

  20. Relationship between the Compressive and Tensile Strength of Recycled Concrete

    International Nuclear Information System (INIS)

    El Dalati, R.; Haddad, S.; Matar, P.; Chehade, F.H

    2011-01-01

    Concrete recycling consists of crushing the concrete provided by demolishing the old constructions, and of using the resulted small pieces as aggregates in the new concrete compositions. The resulted aggregates are called recycled aggregates and the new mix of concrete containing a percentage of recycled aggregates is called recycled concrete. Our previous researches have indicated the optimal percentages of recycled aggregates to be used for different cases of recycled concrete related to the original aggregates nature. All results have shown that the concrete compressive strength is significantly reduced when using recycled aggregates. In order to obtain realistic values of compressive strength, some tests have been carried out by adding water-reducer plasticizer and a specified additional quantity of cement. The results have shown that for a limited range of plasticizer percentage, and a fixed value of additional cement, the compressive strength has reached reasonable value. This paper treats of the effect of using recycled aggregates on the tensile strength of concrete, where concrete results from the special composition defined by our previous work. The aim is to determine the relationship between the compressive and tensile strength of recycled concrete. (author)

  1. Study of CSR longitudinal bunch compression cavity

    International Nuclear Information System (INIS)

    Yin Dayu; Li Peng; Liu Yong; Xie Qingchun

    2009-01-01

    The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring (CSR)is an important issue. Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90 degree rotation in the longitudinal phase space. The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude. For this purpose, the CSR longitudinal bunch compression cavity, loaded with FINEMET-FT-1M is studied and simulated with MAFIA code. In this paper, the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238 U 72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code. The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV, and the cavity can be used to compress heavy ions in the CSR. (authors)

  2. Waves and compressible flow

    CERN Document Server

    Ockendon, Hilary

    2016-01-01

    Now in its second edition, this book continues to give readers a broad mathematical basis for modelling and understanding the wide range of wave phenomena encountered in modern applications.  New and expanded material includes topics such as elastoplastic waves and waves in plasmas, as well as new exercises.  Comprehensive collections of models are used to illustrate the underpinning mathematical methodologies, which include the basic ideas of the relevant partial differential equations, characteristics, ray theory, asymptotic analysis, dispersion, shock waves, and weak solutions. Although the main focus is on compressible fluid flow, the authors show how intimately gasdynamic waves are related to wave phenomena in many other areas of physical science.   Special emphasis is placed on the development of physical intuition to supplement and reinforce analytical thinking. Each chapter includes a complete set of carefully prepared exercises, making this a suitable textbook for students in applied mathematics, ...

  3. Taking into care metastatic medullary compressions; Prise en charge des compressions medullaires metastatiques

    Energy Technology Data Exchange (ETDEWEB)

    Dupin, C.; Feuvret, L. [Groupe hospitalier Pitie-Salpetriere, 75 - Paris (France)

    2010-10-15

    As between 5 and 14 per cent of patients suffering from cancer will suffer from a metastatic medullary compression which severely impacts the vital and functional prognostic, the authors proposes an overview of the different techniques used to take these compressions into care: surgery, radiotherapy and cortico-therapy. They describe their positive and negative impacts. Short communication

  4. Unveil Compressed Sensing

    OpenAIRE

    Liu, Xiteng

    2013-01-01

    We discuss the applicability of compressed sensing theory. We take a genuine look at both experimental results and theoretical works. We answer the following questions: 1) What can compressed sensing really do? 2) More importantly, why?

  5. A Compressive Superresolution Display

    KAUST Repository

    Heide, Felix

    2014-06-22

    In this paper, we introduce a new compressive display architecture for superresolution image presentation that exploits co-design of the optical device configuration and compressive computation. Our display allows for superresolution, HDR, or glasses-free 3D presentation.

  6. Microbunching and RF Compression

    International Nuclear Information System (INIS)

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.

    2010-01-01

    Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.

  7. Hyperspectral data compression

    CERN Document Server

    Motta, Giovanni; Storer, James A

    2006-01-01

    Provides a survey of results in the field of compression of remote sensed 3D data, with a particular interest in hyperspectral imagery. This work covers topics such as compression architecture, lossless compression, lossy techniques, and more. It also describes a lossless algorithm based on vector quantization.

  8. Compression test assembly

    Science.gov (United States)

    Kariotis, A. H. (Inventor)

    1973-01-01

    A compression test assembly is described which prevents buckling of small diameter rigid specimens undergoing compression testing and permits attachment of extensometers for strain measurements. The test specimen is automatically aligned and laterally supported when compressive force is applied to the end caps and transmitted to the test specimen during testing.

  9. Compressible effect algebras

    Science.gov (United States)

    Gudder, Stan

    2004-08-01

    We define a special type of additive map J on an effect algebra E called a compression. We call J(1) the focus of J and if p is the focus of a compression then p is called a projection. The set of projections in E is denoted by P(E). A compression J is direct if J( a) ≤ a for all a ɛ E. We show that direct compressions are equivalent to projections onto components of cartesian products. An effect algebra E is said to be compressible if every compression on E is uniquely determined by its focus and every compression on E has a supplement. We define and characterize the commutant C(p) of a projection p and show that a compression with focus p is direct if and only if C(p) = E. We show that P(E) is an orthomodular poset. It is proved that the cartesian product of effect algebras is compressible if and only if each component is compressible. We then consider compressible sequential effect algebras, Lüders maps and conditional probabilities.

  10. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter

    2008-01-01

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to ......-2 bits per node. Empirical results for our compression technique are presented, including comparisons with previously introduced techniques, showing that the new technique dominate on all tested instances......The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  11. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Rune Hansen, Esben; Srinivasa Rao, S.; Tiedemann, Peter

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to ......-2 bits per node. Empirical results for our compression technique are presented, including comparisons with previously introduced techniques, showing that the new technique dominate on all tested instances.......The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  12. Compression and fast retrieval of SNP data.

    Science.gov (United States)

    Sambo, Francesco; Di Camillo, Barbara; Toffolo, Gianna; Cobelli, Claudio

    2014-11-01

    The increasing interest in rare genetic variants and epistatic genetic effects on complex phenotypic traits is currently pushing genome-wide association study design towards datasets of increasing size, both in the number of studied subjects and in the number of genotyped single nucleotide polymorphisms (SNPs). This, in turn, is leading to a compelling need for new methods for compression and fast retrieval of SNP data. We present a novel algorithm and file format for compressing and retrieving SNP data, specifically designed for large-scale association studies. Our algorithm is based on two main ideas: (i) compress linkage disequilibrium blocks in terms of differences with a reference SNP and (ii) compress reference SNPs exploiting information on their call rate and minor allele frequency. Tested on two SNP datasets and compared with several state-of-the-art software tools, our compression algorithm is shown to be competitive in terms of compression rate and to outperform all tools in terms of time to load compressed data. Our compression and decompression algorithms are implemented in a C++ library, are released under the GNU General Public License and are freely downloadable from http://www.dei.unipd.it/~sambofra/snpack.html. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Shock absorbing properties of toroidal shells under compression, 3

    International Nuclear Information System (INIS)

    Sugita, Yuji

    1985-01-01

    The author has previously presented the static load-deflection relations of a toroidal shell subjected to axisymmetric compression between rigid plates and those of its outer half when subjected to lateral compression. In both these cases, the analytical method was based on the incremental Rayleigh-Ritz method. In this paper, the effects of compression angle and strain rate on the load-deflection relations of the toroidal shell are investigated for its use as a shock absorber for the radioactive material shipping cask which must keep its structural integrity even after accidental falls at any angle. Static compression tests have been carried out at four angles of compression, 10 0 , 20 0 , 50 0 , 90 0 and the applications of the preceding analytical method have been discussed. Dynamic compression tests have also been performed using the free-falling drop hammer. The results are compared with those in the static compression tests. (author)

  14. Radial and axial compression of pure electron

    International Nuclear Information System (INIS)

    Park, Y.; Soga, Y.; Mihara, Y.; Takeda, M.; Kamada, K.

    2013-01-01

    Experimental studies are carried out on compression of the density distribution of a pure electron plasma confined in a Malmberg-Penning Trap in Kanazawa University. More than six times increase of the on-axis density is observed under application of an external rotating electric field that couples to low-order Trivelpiece-Gould modes. Axial compression of the density distribution with the axial length of a factor of two is achieved by controlling the confining potential at both ends of the plasma. Substantial increase of the axial kinetic energy is observed during the axial compression. (author)

  15. Compressive Force With 2-Screw and 3-Screw Subtalar Joint Arthrodesis With Headless Compression Screws.

    Science.gov (United States)

    Matsumoto, Takumi; Glisson, Richard R; Reidl, Markus; Easley, Mark E

    2016-12-01

    Joint compression is an essential element of successful arthrodesis. Although subtalar joint compression generated by conventional screws has been quantified in the laboratory, compression obtainable with headless screws that rely on variable thread pitch to achieve bony contact has not been assessed. This study measured subtalar joint compression achieved by 2 posteriorly placed contemporary headless, variable-pitch screws, and quantified additional compression gained by placing a third screw anteriorly. Ten, unpaired fresh-frozen cadaveric subtalar joints were fixed sequentially using 2 diverging posterior screws (one directed into the talar dome, the other into the talar neck), 2 parallel posterior screws (both ending in the talar dome), and 2 parallel screws with an additional anterior screw inserted from the plantar calcaneus into the talar neck. Joint compression was quantified directly during screw insertion using a novel custom-built measuring device. The mean compression generated by 2 diverging posterior screws was 246 N. Two parallel posterior screws produced 294 N of compression, and augmentation of that construct with a third, anterior screw increased compression to 345 N (P screw fixation was slightly less than that reported previously for subtalar joint fixation with 2 conventional lag screws, but was comparable when a third screw was added. Under controlled testing conditions, 2 tapered, variable-pitch screws generated somewhat less compression than previously reported for 2-screw fixation with conventional headed screws. A third screw placed anteriorly increased compression significantly. Because headless screws are advantageous where prominent screw heads are problematic, such as the load-bearing surface of the foot, their effectiveness compared to other screws should be established to provide an objective basis for screw selection. Augmenting fixation with an anterior screw may be desirable when conditions for fusion are suboptimal. © The Author(s

  16. zlib compression library

    OpenAIRE

    Gailly, Jean-loup; Adler, Mark

    2004-01-01

    (taken from http://www.gzip.org/ on 2004-12-01) zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress(1) and in the GIF image format, the compression method currently used in zlib essentially never expands the data. (LZW ca...

  17. Towards Natural Transition in Compressible Boundary Layers

    Science.gov (United States)

    2016-06-29

    19b. TELEPHONE NUMBER (Include area code) The public reporting burden for this collection of information is estimated to average 1 hour per response...in the spanwise direction, and reduced upstream, to perform calculation only in the region occupied by the wave packet. The domain was resized

  18. Towards Natural Transition in Compressible Boundary Layers

    Science.gov (United States)

    2016-06-29

    0.9 were observed to be completely different. In the incompressible boundary layer localized lambda vortex struc- tures were observed, that could be...10 2 Physical problem and computational setup 11 2.1 Governing equations...studies on secondary instability. This coincides with a noticeable improvement in the calculation capacity and the cost reduction of the computational

  19. Compression experiments on the TOSKA tokamak

    International Nuclear Information System (INIS)

    Cima, G.; McGuire, K.M.; Robinson, D.C.; Wootton, A.J.

    1980-10-01

    Results from minor radius compression experiments on a tokamak plasma in TOSCA are reported. The compression is achieved by increasing the toroidal field up to twice its initial value in 200μs. Measurements show that particles and magnetic flux are conserved. When the initial energy confinement time is comparable with the compression time, energy gains are greater than for an adiabatic change of state. The total beta value increases. Central beta values approximately 3% are measured when a small major radius compression is superimposed on a minor radius compression. Magnetic field fluctuations are affected: both the amplitude and period decrease. Starting from low energy confinement times, approximately 200μs, increases in confinement times up to approximately 1 ms are measured. The increase in plasma energy results from a large reduction in the power losses during the compression. When the initial energy confinement time is much longer than the compression time, the parameter changes are those expected for an adiabatic change of state. (author)

  20. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...

  1. Double compression: a vision for compressing morbidity and caregiving in dementia.

    Science.gov (United States)

    Cheng, Sheung-Tak

    2014-12-01

    The anticipated rise of dementia prevalence due to global aging may be tackled by morbidity compression through lifestyle changes (i.e., consistent participation in physical and intellectual activities) that promote cognitive reserve. A hypothetical model of cognitive decline due to Alzheimer's disease (AD) and modulation of the clinical trajectory by cognitive reserve is presented. People with higher cognitive reserve are expected to show delay of the mild cognitive impairment phase but faster conversion to AD thereafter. Once conversion to AD is evident, there would be even faster deterioration, resulting in compression of morbidity. When morbidity is compressed, not only is prevalence reduced but the caregiving load is also compressed; this is referred to as "double compression." Research and policy directions are discussed. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. [Compression treatment for burned skin].

    Science.gov (United States)

    Jaafar, Fadhel; Lassoued, Mohamed A; Sahnoun, Mahdi; Sfar, Souad; Cheikhrouhou, Morched

    2012-02-01

    The regularity of a compressive knit is defined as its ability to perform its function in a burnt skin. This property is essential to avoid the phenomenon of rejection of the material or toxicity problems But: Make knits biocompatible with high burnet of human skin. We fabric knits of elastic material. To ensure good adhesion to the skin, we made elastic material, typically a tight loop knitted. The Length of yarn absorbed by stitch and the raw matter are changed with each sample. The physical properties of each sample are measured and compared. Surface modifications are made to these samples by impregnation of microcapsules based on jojoba oil. Knits are compressif, elastic in all directions, light, thin, comfortable, and washable for hygiene issues. In addition, the washing can find their compressive properties. The Jojoba Oil microcapsules hydrated the human burnet skin. This moisturizer is used to the firmness of the wound and it gives flexibility to the skin. Compressive Knits are biocompatible with burnet skin. The mixture of natural and synthetic fibers is irreplaceable in terms comfort and regularity.

  3. Development and assessment of compression technique for medical images using neural network. I. Assessment of lossless compression

    International Nuclear Information System (INIS)

    Fukatsu, Hiroshi

    2007-01-01

    This paper describes assessment of the lossless compression of a new efficient compression technique (JIS system) using neural network that the author and co-workers have recently developed. At first, theory is explained for encoding and decoding the data. Assessment is done on 55 images each of chest digital roentgenography, digital mammography, 64-row multi-slice CT, 1.5 Tesla MRI, positron emission tomography (PET) and digital subtraction angiography, which are lossless-compressed by the present JIS system to see the compression rate and loss. For comparison, those data are also JPEG lossless-compressed. Personal computer (PC) is an Apple MacBook Pro with configuration of Boot Camp for Windows environment. The present JIS system is found to have a more than 4 times higher efficiency than the usual compressions which compressing the file volume to only 1/11 in average, and thus to be importantly responsible to the increasing medical imaging data. (R.T.)

  4. Impact of hydrogen insertion on vehicular natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Strangueto, Karina Maretti; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. of Mechanical Engineering. Energy Dept.], Email: karinakms@fem.unicamp.br

    2010-07-01

    This article aims to analyze the possibility of insertion of hydrogen in the vehicular natural gas or even the insertion of the hydrogen in the compressed natural gas used in Brazil. For the production of this hydrogen, the spilled turbinable energy from Itaipu would be harnessed. The calculation of production can be extended to other power plants which are close to the natural gas pipelines, where the hydrogen would be introduced. Then, it was analyzed the consumption of natural gas in vehicles in Brazil, the regulation of transportation, the sales of compressed natural gas to fuelling station, the specifications that the piped gas should follow to be sold, and how much hydrogen could be accepted in the mix. (author)

  5. DSP Implementation of Image Compression by Multiresolutional Analysis

    Directory of Open Access Journals (Sweden)

    K. Vlcek

    1998-04-01

    Full Text Available Wavelet algorithms allow considerably higher compression rates compared to Fourier transform based methods. The most important field of applications of wavelet transforms is that the image is captured in few wavelet coefficients. The successful applications in compression of image or in series of images in both the space and the time dimensions. Compression algorithms exploit the multi-scale nature of the wavelet transform.

  6. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    Energy Technology Data Exchange (ETDEWEB)

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity

  7. Magnetic surface compression heating in the heliotron device

    International Nuclear Information System (INIS)

    Uo, K.; Motojima, O.

    1982-01-01

    The slow adiabatic compression of the plasma in the heliotron device is examined. It has a prominent characteristic that the plasma equilibrium always exists at each stage of the compression. The heating efficiency is calculated. We show the possible access to fusion. A large amount of the initial investment for the heating system (NBI or RF) is reduced by using the magnetic surface compression heating. (author)

  8. Very low rate compression of speckled SAR imagery

    Energy Technology Data Exchange (ETDEWEB)

    Eichel, P.H. [Sandia National Labs., Albuquerque, NM (United States); Ives, R.W. [Navy (United States)

    1998-01-01

    Synthetic aperture radars produce coherent, and speckled, high resolution images of the ground. Because modern systems can generate large amounts of imagery, there is substantial interest in applying image compression techniques to these products. In this paper, the authors examine the properties of speckled imagery relevant to the task of data compression. In particular, they demonstrate the advisability of compressing the speckle mean function rather than the literal image. The theory, methodology, and an example are presented.

  9. Nuclear data compression and reconstruction via discrete wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Ryong; Cho, Nam Zin [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    Discrete Wavelet Transforms (DWTs) are recent mathematics, and begin to be used in various fields. The wavelet transform can be used to compress the signal and image due to its inherent properties. We applied the wavelet transform compression and reconstruction to the neutron cross section data. Numerical tests illustrate that the signal compression using wavelet is very effective to reduce the data saving spaces. 7 refs., 4 figs., 3 tabs. (Author)

  10. Testing framework for compression methods

    OpenAIRE

    Štoček, Ondřej

    2008-01-01

    There are many algorithms for data compression. These compression methods often achieve different compression rate and also use computer resources differently. In practice a combination of compression is usually used instead of standalone compression methods. The software tool can be evolved, where we can easily combine existing compression methods to new one and test it consequently. Main goal of this work is to propound such tool and implement it. Further goal is to implement basic library ...

  11. SIMULACIÓN HORARIA DE UN SISTEMA DE REFRIGERACIÓN COMBINADO EYECTOR-COMPRESIÓN DE VAPOR ASISTIDO POR ENERGÍA SOLAR Y GAS NATURAL HOURLY SIMULATION OF A COMBINED EJECTOR-VAPOR COMPRESSION REFRIGERATION SYSTEM ASSISTED BY SOLAR ENERGY AND NATURAL GAS

    Directory of Open Access Journals (Sweden)

    Humberto Vidal

    2009-04-01

    double stage ejector cooling cycle assisted by solar energy system appears as an attractive solution to this problem. The first stage is performed by a mechanical compression cycle with R-134a as the working fluid, while the second stage is performed by a thermally driven ejector cycle with R-141b. Flat plate collectors and an auxiliary energy burner provide heat to the ejector cycle. This paper describes the hourly simulation of a combined ejector-vapor compression refrigeration system assisted by solar energy and natural gas. The combined solar refrigeration system is modeled using the TRNSYS-EES simulation tool and the typical meteorological year data containing the weather data of Florianópolis Brazil. The results obtained from the computational simulation performed in this system show that the combined ejector-vapor compression cooling cycle is more advantageous than the simple ejector cooling cycle. Finally, the computational model developed in this paper might be used to perform a thermo-economical optimization of the system in future works.

  12. Radio frequency pulse compression

    International Nuclear Information System (INIS)

    Farkas, Z.D.

    1988-12-01

    High gradients require peak powers. One possible way to generate high peak powers is to generate a relatively long pulse at a relatively low power and compress it into a shorter pulse with higher peak power. It is possible to compress before dc to rf conversion as is done for the relativistic klystron or after dc to rf conversion as is done with SLED. In this note only radio frequency pulse compression (RFPC) is considered. Three methods of RFPC will be discussed: SLED, BEC, and REC. 3 refs., 8 figs., 1 tab

  13. Compression of the digitized X-ray images

    International Nuclear Information System (INIS)

    Terae, Satoshi; Miyasaka, Kazuo; Fujita, Nobuyuki; Takamura, Akio; Irie, Goro; Inamura, Kiyonari.

    1987-01-01

    Medical images are using an increased amount of space in the hospitals, while they are not accessed easily. Thus, suitable data filing system and precise data compression will be necessitated. Image quality was evaluated before and after image data compression, using local filing system (MediFile 1000, NEC Co.) and forty-seven modes of compression parameter. For this study X-ray images of 10 plain radiographs and 7 contrast examinations were digitized using a film reader of CCD sensor in MediFile 1000. Those images were compressed into forty-seven kinds of image data to save in an optical disc and then the compressed images were reconstructed. Each reconstructed image was compared with non-compressed images in respect to several regions of our interest by four radiologists. Compression and extension of radiological images were promptly made by employing the local filing system. Image quality was much more affected by the ratio of data compression than by the mode of parameter itself. In another word, the higher compression ratio became, the worse the image quality were. However, image quality was not significantly degraded until the compression ratio was about 15: 1 on plain radiographs and about 8: 1 on contrast studies. Image compression by this technique will be admitted by diagnostic radiology. (author)

  14. ICER-3D Hyperspectral Image Compression Software

    Science.gov (United States)

    Xie, Hua; Kiely, Aaron; Klimesh, matthew; Aranki, Nazeeh

    2010-01-01

    Software has been developed to implement the ICER-3D algorithm. ICER-3D effects progressive, three-dimensional (3D), wavelet-based compression of hyperspectral images. If a compressed data stream is truncated, the progressive nature of the algorithm enables reconstruction of hyperspectral data at fidelity commensurate with the given data volume. The ICER-3D software is capable of providing either lossless or lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The compression algorithm, which was derived from the ICER image compression algorithm, includes wavelet-transform, context-modeling, and entropy coding subalgorithms. The 3D wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of sets of hyperspectral image data, while facilitating elimination of spectral ringing artifacts, using a technique summarized in "Improving 3D Wavelet-Based Compression of Spectral Images" (NPO-41381), NASA Tech Briefs, Vol. 33, No. 3 (March 2009), page 7a. Correlation is further exploited by a context-modeling subalgorithm, which exploits spectral dependencies in the wavelet-transformed hyperspectral data, using an algorithm that is summarized in "Context Modeler for Wavelet Compression of Hyperspectral Images" (NPO-43239), which follows this article. An important feature of ICER-3D is a scheme for limiting the adverse effects of loss of data during transmission. In this scheme, as in the similar scheme used by ICER, the spatial-frequency domain is partitioned into rectangular error-containment regions. In ICER-3D, the partitions extend through all the wavelength bands. The data in each partition are compressed independently of those in the other partitions, so that loss or corruption of data from any partition does not affect the other partitions. Furthermore, because compression is progressive within each partition, when data are lost, any data from that partition received

  15. Compressed Video Segmentation

    National Research Council Canada - National Science Library

    Kobla, Vikrant; Doermann, David S; Rosenfeld, Azriel

    1996-01-01

    ... changes in content and camera motion. The analysis is performed in the compressed domain using available macroblock and motion vector information, and if necessary, discrete cosine transform (DCT) information...

  16. Biaxial compression test technique

    Science.gov (United States)

    Hansard, E. T.

    1975-01-01

    Fixture and technique have been developed for predicting behavior of stiffened skin panels under biaxial compressive loading. Tester can load test panel independently in longitudinal and transverse directions. Data can also be obtained in combined mode.

  17. Muon cooling: longitudinal compression.

    Science.gov (United States)

    Bao, Yu; Antognini, Aldo; Bertl, Wilhelm; Hildebrandt, Malte; Khaw, Kim Siang; Kirch, Klaus; Papa, Angela; Petitjean, Claude; Piegsa, Florian M; Ritt, Stefan; Sedlak, Kamil; Stoykov, Alexey; Taqqu, David

    2014-06-06

    A 10  MeV/c positive muon beam was stopped in helium gas of a few mbar in a magnetic field of 5 T. The muon "swarm" has been efficiently compressed from a length of 16 cm down to a few mm along the magnetic field axis (longitudinal compression) using electrostatic fields. The simulation reproduces the low energy interactions of slow muons in helium gas. Phase space compression occurs on the order of microseconds, compatible with the muon lifetime of 2  μs. This paves the way for the preparation of a high-quality low-energy muon beam, with an increase in phase space density relative to a standard surface muon beam of 10^{7}. The achievable phase space compression by using only the longitudinal stage presented here is of the order of 10^{4}.

  18. Deterministic Compressed Sensing

    Science.gov (United States)

    2011-11-01

    programs. Examples of such algorithms are the interior point methods [51, 52], Lasso modification to LARS [106, 171], homotopy methods [99], weighted...component analysis . IEEE Signal Processing Letters, 9(2):40–42, 2002. [171] S. J. Kim, K. Koh, M. Lustig, S. Boyd, and D. Gorinevsky. A method for...53 7.3 Analysis of the GAME Algorithm . . . . . . . . . . . . . . . . . . . . 57 III Expander-Based Compressed Sensing 61 8 Efficient Compressed

  19. Blind Compressed Sensing

    OpenAIRE

    Gleichman, Sivan; Eldar, Yonina C.

    2011-01-01

    The fundamental principle underlying compressed sensing is that a signal, which is sparse under some basis representation, can be recovered from a small number of linear measurements. However, prior knowledge of the sparsity basis is essential for the recovery process. This work introduces the concept of blind compressed sensing, which avoids the need to know the sparsity basis in both the sampling and the recovery process. We suggest three possible constraints on the sparsity basis that can ...

  20. Spinal cord compression due to metastases

    International Nuclear Information System (INIS)

    Azevedo, C.M. de; Matushita, J.P.K.; Silva, M.A.F. da; Koch, H.A.

    1986-01-01

    A study of 20 patients with medullary compression syndrome due to lesions not related to the central nervous system is presented. Plain films of the spine and myelography are made to determine the level of osseous involvement, the level of the spinal block and to planning radiotherapy. (Author) [pt

  1. Author Details

    African Journals Online (AJOL)

    Rae, W. Vol 12, No 2 (2008) - Articles Computed Radiography Exposure Indices in Mammography Abstract PDF · Vol 13, No 3 (2009) - Articles Mammographic CAD: Correlation of regions in ipsilateral views – a pilot study. Abstract PDF · Vol 13, No 4 (2009) - Articles The relationship between compression force, image ...

  2. Author Details

    African Journals Online (AJOL)

    Shukran, M.A.M.. Vol 9, No 3S (2017): Special Issue - Articles An analysis of a discrete cosine transform (DCT)compression technique on low level features of image for image retrieval system. Abstract PDF · Vol 9, No 3S (2017): Special Issue - Articles The study of technological prevention method of road accident related to ...

  3. Author Details

    African Journals Online (AJOL)

    ... Bombax ceiba and their Binary Mixture Abstract · Vol 10, No 1 (2013) - Articles Optimization of binder, disintegrant and compression pressure for paracetamol tablet formulations. Abstract · Vol 10, No 1 (2013) - Articles The potential use ofKhaya senegalensis oil as base in paracetamol suppository formulation. Abstract.

  4. Author Details

    African Journals Online (AJOL)

    Unusual presentation and inconclusive biopsy render fibroadenoma in two young females a diagnostic dilemma. Abstract PDF · Vol 14, No 3 (2010) - Articles Is airway diameter measured accurately on routine axial CT scans? Comparison with true axial diameter using MPR in children with airway compression owing to ...

  5. Author Details

    African Journals Online (AJOL)

    Herbst, C. Vol 12, No 2 (2008) - Articles Computed Radiography Exposure Indices in Mammography Abstract PDF · Vol 13, No 4 (2009) - Articles The relationship between compression force, image quality and radiation dose in mammography. Abstract PDF. ISSN: 2078-6778. AJOL African Journals Online. HOW TO USE ...

  6. Author Details

    African Journals Online (AJOL)

    Suitability of iron ore tailings and quarry dust as fine aggregates for concrete production. Abstract · Vol 18, No 1-2 (2013) - Articles Predictive equations for compressive strength of concrete based on Schmidt hammer rebound and ultrasonic pulse velocity data. Abstract · Vol 35, No 1 (2016) - Building, Civil & Geotechical ...

  7. Author Details

    African Journals Online (AJOL)

    ... theophylline tablets and capsules. Abstract · Vol 7, No 1 (2009) - Articles Preformulation compatibility screening of dika fat-drug mixtures using differential scanning calorimetry. Abstract · Vol 9, No 2 (2012) - Articles Auxilliary Dry Binding Properties of Some Hydrogenated Vegetable Oils in Direct Compression Tabletting

  8. Author Details

    African Journals Online (AJOL)

    Ezeh, JC. Vol 28, No 1 (2009) - Research papers. Algorithm for Concrete Mix Design Based on British Method Abstract PDF · Vol 28, No 2 (2009) - Research papers. Stability of Axially Compressed Single-Cell Mono-Symmetric Thin-Walled Closed Column Abstract PDF · Vol 28, No 2 (2009) - Research papers. Flexural ...

  9. Author Details

    African Journals Online (AJOL)

    Vol 9 (2005) - Articles A cubic interpolation algorithm for solving non-linear equations. Abstract · Vol 9 (2005) - Articles Explicit presentation of the Colebrook's friction ... for Downhill Compressible Flow in Pipes and Its Solution Abstract · Vol 18 (2011) - Articles A Formula for the Coefficient of Thermal Expansion of Crude Oils

  10. Author Details

    African Journals Online (AJOL)

    Comparative Analysis of the Compressive Strength of Concrete with Gravel and Crushed Over Burnt Bricks as Coarse Aggregates ... Stratification in Waste Stabilization Ponds I: Effects on Pond Parameters ... Engineering CLASSICAL OPTIMIZATION OF BAGASSE ASH CONTENT IN CEMENT-STABILIZED LATERITIC SOIL

  11. Author Details

    African Journals Online (AJOL)

    Ayite, YMXD. Vol 13, No 2 (2011): Series E - Articles Determinatin dúne application des betons de balles de riz dans le batiment au Togo Abstract · Vol 16, No 3 (2014) - Articles Influence du taux de balles de riz sur la resistance a la compression des briques en terre. Abstract. ISSN: 2413-354X. AJOL African Journals ...

  12. Author Details

    African Journals Online (AJOL)

    Anazodo, UGN. Vol 6, No 1 (1982) - Articles Experimental Viscoelastic Characterization of Corn Cob Composited Under Radial Compression Abstract PDF · Vol 15, No 1 (1991) - Research papers. Optimum Stock Control Model for Farm Tractor Spare Parts in Nigeria Abstract PDF. ISSN: 2467-8821. AJOL African Journals ...

  13. Temporal compression in episodic memory for real-life events.

    Science.gov (United States)

    Jeunehomme, Olivier; Folville, Adrien; Stawarczyk, David; Van der Linden, Martial; D'Argembeau, Arnaud

    2017-11-25

    Remembering an event typically takes less time than experiencing it, suggesting that episodic memory represents past experience in a temporally compressed way. Little is known, however, about how the continuous flow of real-life events is summarised in memory. Here we investigated the nature and determinants of temporal compression by directly comparing memory contents with the objective timing of events as measured by a wearable camera. We found that episodic memories consist of a succession of moments of prior experience that represent events with varying compression rates, such that the density of retrieved information is modulated by goal processing and perceptual changes. Furthermore, the results showed that temporal compression rates remain relatively stable over one week and increase after a one-month delay, particularly for goal-related events. These data shed new light on temporal compression in episodic memory and suggest that compression rates are adaptively modulated to maintain current goal-relevant information.

  14. Roofbolters with compressed-air rotators

    Science.gov (United States)

    Lantsevich, MA; Repin Klishin, AA, VI; Kokoulin, DI

    2018-03-01

    The specifications of the most popular roofbolters of domestic and foreign manufacture currently in operation in coal mines are discussed. Compressed-air roofbolters SAP and SAP2 designed at the Institute of Mining are capable of drilling in hard rocks. The authors describe the compressed-air rotator of SAP2 roofbolter with alternate motion rotors. From the comparative analysis of characteristics of SAP and SAP 2 roofbolters, the combination of high-frequency axial and rotary impacts on a drilling tool in SAP2 ensure efficient drilling in rocks with the strength up to 160 MPa.

  15. Localized Fire Protection Assessment for Vehicle Compressed Hydrogen Containers

    Science.gov (United States)

    2010-03-01

    Industry has identified localized flame impingement on high pressure composite storage cylinders as an area requiring research due to several catastrophic failures in recent years involving compressed natural gas (CNG) vehicles. Current standards and...

  16. Channel box compression device

    International Nuclear Information System (INIS)

    Nakamizo, Hiroshi; Tanaka, Yuki.

    1996-01-01

    The device of the present invention reduces the volume of spent fuel channel boxes of power plant facilities to eliminate secondary wastes, suppress generation of radiation sources and improve storage space efficiency. The device has a box-like shape. A support frame is disposed on the lateral side of the box for supporting spent channel boxes. A horizontal transferring unit and a vertical transferring compression unit driven by a driving mechanism are disposed in the support frame. Further, the compression unit may have a rotational compression roller so as to move freely in the transferring unit. In addition, the transferring unit and the driving mechanism may be disposed outside of pool water. With such a constitution, since spent channel boxes are compressed and bent by horizontal movement of the transferring unit and the vertical movement of the compression unit, no cut pieces or cut powders are generated. Further, if the transferring unit and the driving mechanism are disposed outside of the pool water, it is not necessary to make them waterproof, which facilitates the maintenance. (I.S.)

  17. Optical pulse compression

    International Nuclear Information System (INIS)

    Glass, A.J.

    1975-01-01

    The interest in using large lasers to achieve a very short and intense pulse for generating fusion plasma has provided a strong impetus to reexamine the possibilities of optical pulse compression at high energy. Pulse compression allows one to generate pulses of long duration (minimizing damage problems) and subsequently compress optical pulses to achieve the short pulse duration required for specific applications. The ideal device for carrying out this program has not been developed. Of the two approaches considered, the Gires--Tournois approach is limited by the fact that the bandwidth and compression are intimately related, so that the group delay dispersion times the square of the bandwidth is about unity for all simple Gires--Tournois interferometers. The Treacy grating pair does not suffer from this limitation, but is inefficient because diffraction generally occurs in several orders and is limited by the problem of optical damage to the grating surfaces themselves. Nonlinear and parametric processes were explored. Some pulse compression was achieved by these techniques; however, they are generally difficult to control and are not very efficient. (U.S.)

  18. Relationship between pore structure and compressive strength of ...

    Indian Academy of Sciences (India)

    Keywords. Pore structure; compressive strength; concrete; statistical model; mercury intrusion porosimetry (MIP) ... Author Affiliations. J BU1 Z TIAN. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, People's Republic of China ...

  19. Self contained compressed air breathing apparatus to facilitate personnel decontamination

    International Nuclear Information System (INIS)

    McDonald, C.W.

    1963-11-01

    This report describes the modification of a Self Contained Compressed Air Breathing Apparatus to provide extended respiratory protection to grossly contaminated personnel during a decontamination period which may exceed the duration of the Breathing Apparatus air supply. (author)

  20. Author Details

    African Journals Online (AJOL)

    Etude des paramètres de compressibilité et de cisaillement de l'argile-sableuse de la région de Douala au Cameroun Details PDF · Vol 3, No 2 (2003) - Articles Effet du remaniement par décompression de L'échantillon sur la résistance au cisaillement de l'argile-sableuse jaunatre de Ndogbong dans la région de Douala ...

  1. Celiac artery compression syndrome.

    Science.gov (United States)

    Kokotsakis, J N; Lambidis, C D; Lioulias, A G; Skouteli, E T; Bastounis, E A; Livesay, J J

    2000-04-01

    Celiac artery compression syndrome occurs when the median arcuate ligament of the diaphragm causes extrinsic compression of the celiac trunk. We report a case of a 65-year-old woman who presented with a three-month history of postprandial abdominal pain, nausea and some emesis, without weight loss. There was a bruit in the upper mid-epigastrium and the lateral aortic arteriography revealed a significant stenosis of the celiac artery. At operation, the celiac axis was found to be severely compressed anteriorly by fibers forming the inferior margin of the arcuate ligament of the diaphragm. The ligament was cut and a vein by-pass from the supraceliac aorta to the distal celiac artery was performed. The patient remains well and free of symptoms two and a half years since operation.In this report we discuss the indications and the therapeutic options of this syndrome as well as a review of the literature is being given.

  2. Isentropic Compression of Argon

    International Nuclear Information System (INIS)

    Oona, H.; Solem, J.C.; Veeser, L.R.; Ekdahl, C.A.; Rodriquez, P.J.; Younger, S.M.; Lewis, W.; Turley, W.D.

    1997-01-01

    We are studying the transition of argon from an insulator to a conductor by compressing the frozen gas isentropically to pressures at which neighboring atomic orbitals overlap sufficiently to allow some electron motion between atoms. Argon and the other rare gases have closed electron shells and therefore remain montomic, even when they solidify. Their simple structure makes it likely that any measured change in conductivity is due to changes in the atomic structure, not in molecular configuration. As the crystal is compressed the band gap closes, allowing increased conductivity. We have begun research to determine the conductivity at high pressures, and it is our intention to determine the compression at which the crystal becomes a metal

  3. Gmz: a Gml Compression Model for Webgis

    Science.gov (United States)

    Khandelwal, A.; Rajan, K. S.

    2017-09-01

    Geography markup language (GML) is an XML specification for expressing geographical features. Defined by Open Geospatial Consortium (OGC), it is widely used for storage and transmission of maps over the Internet. XML schemas provide the convenience to define custom features profiles in GML for specific needs as seen in widely popular cityGML, simple features profile, coverage, etc. Simple features profile (SFP) is a simpler subset of GML profile with support for point, line and polygon geometries. SFP has been constructed to make sure it covers most commonly used GML geometries. Web Feature Service (WFS) serves query results in SFP by default. But it falls short of being an ideal choice due to its high verbosity and size-heavy nature, which provides immense scope for compression. GMZ is a lossless compression model developed to work for SFP compliant GML files. Our experiments indicate GMZ achieves reasonably good compression ratios and can be useful in WebGIS based applications.

  4. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...... correlation to the curing time. The experiments show no correlation between the anisotropy and the curing time and a small strength difference between the two drilling directions. The literature shows variations on which drilling direction that is strongest. Based on a Monto Carlo simulation of the expected...

  5. Image data compression investigation

    Science.gov (United States)

    Myrie, Carlos

    1989-01-01

    NASA continuous communications systems growth has increased the demand for image transmission and storage. Research and analysis was conducted on various lossy and lossless advanced data compression techniques or approaches used to improve the efficiency of transmission and storage of high volume stellite image data such as pulse code modulation (PCM), differential PCM (DPCM), transform coding, hybrid coding, interframe coding, and adaptive technique. In this presentation, the fundamentals of image data compression utilizing two techniques which are pulse code modulation (PCM) and differential PCM (DPCM) are presented along with an application utilizing these two coding techniques.

  6. The compressed word problem for groups

    CERN Document Server

    Lohrey, Markus

    2014-01-01

    The Compressed Word Problem for Groups provides a detailed exposition of known results on the compressed word problem, emphasizing efficient algorithms for the compressed word problem in various groups. The author presents the necessary background along with the most recent results on the compressed word problem to create a cohesive self-contained book accessible to computer scientists as well as mathematicians. Readers will quickly reach the frontier of current research which makes the book especially appealing for students looking for a currently active research topic at the intersection of group theory and computer science. The word problem introduced in 1910 by Max Dehn is one of the most important decision problems in group theory. For many groups, highly efficient algorithms for the word problem exist. In recent years, a new technique based on data compression for providing more efficient algorithms for word problems, has been developed, by representing long words over group generators in a compres...

  7. Virtually Lossless Compression of Astrophysical Images

    Directory of Open Access Journals (Sweden)

    Stefano Baronti

    2005-09-01

    Full Text Available We describe an image compression strategy potentially capable of preserving the scientific quality of astrophysical data, simultaneously allowing a consistent bandwidth reduction to be achieved. Unlike strictly lossless techniques, by which moderate compression ratios are attainable, and conventional lossy techniques, in which the mean square error of the decoded data is globally controlled by users, near-lossless methods are capable of locally constraining the maximum absolute error, based on user's requirements. An advanced lossless/near-lossless differential pulse code modulation (DPCM scheme, recently introduced by the authors and relying on a causal spatial prediction, is adjusted to the specific characteristics of astrophysical image data (high radiometric resolution, generally low noise, etc.. The background noise is preliminarily estimated to drive the quantization stage for high quality, which is the primary concern in most of astrophysical applications. Extensive experimental results of lossless, near-lossless, and lossy compression of astrophysical images acquired by the Hubble space telescope show the advantages of the proposed method compared to standard techniques like JPEG-LS and JPEG2000. Eventually, the rationale of virtually lossless compression, that is, a noise-adjusted lossles/near-lossless compression, is highlighted and found to be in accordance with concepts well established for the astronomers' community.

  8. Compressed sensing for STEM tomography.

    Science.gov (United States)

    Donati, Laurène; Nilchian, Masih; Trépout, Sylvain; Messaoudi, Cédric; Marco, Sergio; Unser, Michael

    2017-08-01

    A central challenge in scanning transmission electron microscopy (STEM) is to reduce the electron radiation dosage required for accurate imaging of 3D biological nano-structures. Methods that permit tomographic reconstruction from a reduced number of STEM acquisitions without introducing significant degradation in the final volume are thus of particular importance. In random-beam STEM (RB-STEM), the projection measurements are acquired by randomly scanning a subset of pixels at every tilt view. In this work, we present a tailored RB-STEM acquisition-reconstruction framework that fully exploits the compressed sensing principles. We first demonstrate that RB-STEM acquisition fulfills the "incoherence" condition when the image is expressed in terms of wavelets. We then propose a regularized tomographic reconstruction framework to recover volumes from RB-STEM measurements. We demonstrate through simulations on synthetic and real projection measurements that the proposed framework reconstructs high-quality volumes from strongly downsampled RB-STEM data and outperforms existing techniques at doing so. This application of compressed sensing principles to STEM paves the way for a practical implementation of RB-STEM and opens new perspectives for high-quality reconstructions in STEM tomography. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Simulating coupled dynamics of a rigid-flexible multibody system and compressible fluid

    Science.gov (United States)

    Hu, Wei; Tian, Qiang; Hu, HaiYan

    2018-04-01

    As a subsequent work of previous studies of authors, a new parallel computation approach is proposed to simulate the coupled dynamics of a rigid-flexible multibody system and compressible fluid. In this approach, the smoothed particle hydrodynamics (SPH) method is used to model the compressible fluid, the natural coordinate formulation (NCF) and absolute nodal coordinate formulation (ANCF) are used to model the rigid and flexible bodies, respectively. In order to model the compressible fluid properly and efficiently via SPH method, three measures are taken as follows. The first is to use the Riemann solver to cope with the fluid compressibility, the second is to define virtual particles of SPH to model the dynamic interaction between the fluid and the multibody system, and the third is to impose the boundary conditions of periodical inflow and outflow to reduce the number of SPH particles involved in the computation process. Afterwards, a parallel computation strategy is proposed based on the graphics processing unit (GPU) to detect the neighboring SPH particles and to solve the dynamic equations of SPH particles in order to improve the computation efficiency. Meanwhile, the generalized-alpha algorithm is used to solve the dynamic equations of the multibody system. Finally, four case studies are given to validate the proposed parallel computation approach.

  10. Temporal compressive sensing systems

    Science.gov (United States)

    Reed, Bryan W.

    2017-12-12

    Methods and systems for temporal compressive sensing are disclosed, where within each of one or more sensor array data acquisition periods, one or more sensor array measurement datasets comprising distinct linear combinations of time slice data are acquired, and where mathematical reconstruction allows for calculation of accurate representations of the individual time slice datasets.

  11. Compressive CFAR Radar Processing

    NARCIS (Netherlands)

    Anitori, L.; Rossum, W.L. van; Otten, M.P.G.; Maleki, A.; Baraniuk, R.

    2013-01-01

    In this paper we investigate the performance of a combined Compressive Sensing (CS) Constant False Alarm Rate (CFAR) radar processor under different interference scenarios using both the Cell Averaging (CA) and Order Statistic (OS) CFAR detectors. Using the properties of the Complex Approximate

  12. Compressive CFAR radar detection

    NARCIS (Netherlands)

    Anitori, L.; Otten, M.P.G.; Rossum, W.L. van; Maleki, A.; Baraniuk, R.

    2012-01-01

    In this paper we develop the first Compressive Sensing (CS) adaptive radar detector. We propose three novel architectures and demonstrate how a classical Constant False Alarm Rate (CFAR) detector can be combined with ℓ1-norm minimization. Using asymptotic arguments and the Complex Approximate

  13. Gas compression infrared generator

    International Nuclear Information System (INIS)

    Hug, W.F.

    1980-01-01

    A molecular gas is compressed in a quasi-adiabatic manner to produce pulsed radiation during each compressor cycle when the pressure and temperature are sufficiently high, and part of the energy is recovered during the expansion phase, as defined in U.S. Pat. No. 3,751,666; characterized by use of a cylinder with a reciprocating piston as a compressor

  14. Multiple snapshot compressive beamforming

    DEFF Research Database (Denmark)

    Gerstoft, Peter; Xenaki, Angeliki; Mecklenbrauker, Christoph F.

    2015-01-01

    For sound fields observed on an array, compressive sensing (CS) reconstructs the multiple source signals at unknown directions-of-arrival (DOAs) using a sparsity constraint. The DOA estimation is posed as an underdetermined problem expressing the field at each sensor as a phase-lagged superposition...

  15. Compression of Infrared images

    DEFF Research Database (Denmark)

    Mantel, Claire; Forchhammer, Søren

    2017-01-01

    This paper investigates the compression of infrared images with three codecs: JPEG2000, JPEG-XT and HEVC. Results are evaluated in terms of SNR, Mean Relative Squared Error (MRSE) and the HDR-VDP2 quality metric. JPEG2000 and HEVC perform fairy similar and better than JPEG-XT. JPEG2000 performs...

  16. Thermodynamic Analysis of Three Compressed Air Energy Storage Systems: Conventional, Adiabatic, and Hydrogen-Fueled

    OpenAIRE

    Hossein Safaei; Michael J. Aziz

    2017-01-01

    We present analyses of three families of compressed air energy storage (CAES) systems: conventional CAES, in which the heat released during air compression is not stored and natural gas is combusted to provide heat during discharge; adiabatic CAES, in which the compression heat is stored; and CAES in which the compression heat is used to assist water electrolysis for hydrogen storage. The latter two methods involve no fossil fuel combustion. We modeled both a low-temperature and a high-temper...

  17. Ultrahigh Pressure Dynamic Compression

    Science.gov (United States)

    Duffy, T. S.

    2017-12-01

    Laser-based dynamic compression provides a new opportunity to study the lattice structure and other properties of geological materials to ultrahigh pressure conditions ranging from 100 - 1000 GPa (1 TPa) and beyond. Such studies have fundamental applications to understanding the Earth's core as well as the interior structure of super-Earths and giant planets. This talk will review recent dynamic compression experiments using high-powered lasers on materials including Fe-Si, MgO, and SiC. Experiments were conducted at the Omega laser (University of Rochester) and the Linac Coherent Light Source (LCLS, Stanford). At Omega, laser drives as large as 2 kJ are applied over 10 ns to samples that are 50 microns thick. At peak compression, the sample is probed with quasi-monochromatic X-rays from a laser-plasma source and diffraction is recorded on image plates. At LCLS, shock waves are driven into the sample using a 40-J laser with a 10-ns pulse. The sample is probed with X-rays form the LCLS free electron laser providing 1012 photons in a monochromatic pulse near 10 keV energy. Diffraction is recorded using pixel array detectors. By varying the delay between the laser and the x-ray beam, the sample can be probed at various times relative to the shock wave transiting the sample. By controlling the shape and duration of the incident laser pulse, either shock or ramp (shockless) loading can be produced. Ramp compression produces less heating than shock compression, allowing samples to be probed to ultrahigh pressures without melting. Results for iron alloys, oxides, and carbides provide new constraints on equations of state and phase transitions that are relevant to the interior structure of large, extrasolar terrestrial-type planets.

  18. Author Guidelines

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2016-06-01

    the clinical trial registration number at the end of the abstract. The ICMJE also recommends that, when a registration number is available, authors list that number the first time they use a trial acronym to refer to the trial they are reporting or to other trials that they mention in the manuscript. If the data have been deposited in a public repository, authors should state at the end of the abstract the data set name, repository name and number. c. Introduction Provide a context or background for the study (that is, the nature of the problem and its significance. State the specific purpose or research objective of, or hypothesis tested by, the study or observation. Cite only directly pertinent references, and do not include data or conclusions from the work being reported. d. Methods The guiding principle of the Methods section should be clarity about how and why a study was done in a particular way. Methods section should aim to be sufficiently detailed such that others with access to the data would be able to reproduce the results. In general, the section should include only information that was available at the time the plan or protocol for the study was being written; all information obtained during the study belongs in the Results section. If an organization was paid or otherwise contracted to help conduct the research (examples include data collection and management, then this should be detailed in the methods. The Methods section should include a statement indicating that the research was approved or exempted from the need for review by the responsible review committee (institutional or national. If no formal ethics committee is available, a statement indicating that the research was conducted according to the principles of the Declaration of Helsinki should be included. i. Selection and Description of ParticipantsClearly describe the selection of observational or experimental participants (healthy individuals or patients, including controls, including

  19. Sufficient stability condition for alpha-driven velocity-space modes in compression tokamak

    International Nuclear Information System (INIS)

    Yamazaki, K.; Okamoto, M.

    1982-09-01

    Magnetic compression heating may invert the velocity distribution of alpha particles, which leads to velocity-space instabilities. A sufficient stability condition is derived for these modes in compression tokamaks. High-field high-density compression scenario like Zephyr satisfies this stability condition, while medium-field high-temperature compression scheme like TFTR has some possibilities of exciting velocity-space thermonuclear instabilities. (author)

  20. Author Details

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES. Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads.

  1. Compressive creep of silicon nitride

    International Nuclear Information System (INIS)

    Silva, C.R.M. da; Melo, F.C.L. de; Cairo, C.A.; Piorino Neto, F.

    1990-01-01

    Silicon nitride samples were formed by pressureless sintering process, using neodymium oxide and a mixture of neodymium oxide and yttrio oxide as sintering aids. The short term compressive creep behaviour was evaluated over a stress range of 50-300 MPa and temperature range 1200 - 1350 0 C. Post-sintering heat treatments in nitrogen with a stepwise decremental variation of temperature were performed in some samples and microstructural analysis by X-ray diffraction and transmission electron microscopy showed that the secondary crystalline phase which form from the remnant glass are dependent upon composition and percentage of aditives. Stress exponent values near to unity were obtained for materials with low glass content suggesting grain boundary diffusion accommodation processes. Cavitation will thereby become prevalent with increase in stress, temperature and decrease in the degree of crystallization of the grain boundary phase. (author) [pt

  2. Author Guidelines

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2015-12-01

    .c. IntroductionProvide a context or background for the study (that is, the nature of the problem and its significance. State the specific purpose or research objective of, or hypothesis tested by, the study or observation. Cite only directly pertinent references, and do not include data or conclusions from the work being reported.d. MethodsThe guiding principle of the Methods section should be clarity about how and why a study was done in a particular way. Methods section should aim to be sufficiently detailed such that others with access to the data would be able to reproduce the results. In general, the section should include only information that was available at the time the plan or protocol for the study was being written; all information obtained during the study belongs in the Results section. If an organization was paid or otherwise contracted to help conduct the research (examples include data collection and management, then this should be detailed in the methods.The Methods section should include a statement indicating that the research was approved or exempted from the need for review by the responsible review committee (institutional or national. If no formal ethics committee is available, a statement indicating that the research was conducted according to the principles of the Declaration of Helsinki should be included.i. Selection and Description of ParticipantsClearly describe the selection of observational or experimental participants (healthy individuals or patients, in¬cluding controls, including eligibility and exclusion criteria and a description of the source population. Because the relevance of such variables as age, sex, or ethnicity is not always known at the time of study design, researchers should aim for inclusion of representative populations into all study types and at a minimum provide descriptive data for these and other relevant demographic variables. If the study was done involving an exclusive population, for example in only one sex, authors

  3. [Unusual ischemic cord compression by discal hernia (author's transl)].

    Science.gov (United States)

    Vergeret, J; Noble, Y; Barat, M; Guérin, J; Arné, L

    The discal hernia are unfrequent in dorsal localization and neurological appearances are deceptive. We report a case with amyotrophic and fasciculations developing a progressive spinal cord amyotrophy aspect. The complementary investigations (gaz myelography and spinal angiography) show the discal hernia in T11-T12 which was operated successfully. The vascular factor role is discussed about semiologic and pathogenic view.

  4. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2013-01-01

    We introduce a new compression scheme for labeled trees based on top trees [3]. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  5. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2015-01-01

    We introduce a new compression scheme for labeled trees based on top trees. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  6. Fingerprints in compressed strings

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Cording, Patrick Hagge

    2017-01-01

    In this paper we show how to construct a data structure for a string S of size N compressed into a context-free grammar of size n that supports efficient Karp–Rabin fingerprint queries to any substring of S. That is, given indices i and j, the answer to a query is the fingerprint of the substring S......[i,j]. We present the first O(n) space data structures that answer fingerprint queries without decompressing any characters. For Straight Line Programs (SLP) we get O(log⁡N) query time, and for Linear SLPs (an SLP derivative that captures LZ78 compression and its variations) we get O(log⁡log⁡N) query time...

  7. Compresso: Efficient Compression of Segmentation Data for Connectomics

    KAUST Repository

    Matejek, Brian

    2017-09-03

    Recent advances in segmentation methods for connectomics and biomedical imaging produce very large datasets with labels that assign object classes to image pixels. The resulting label volumes are bigger than the raw image data and need compression for efficient storage and transfer. General-purpose compression methods are less effective because the label data consists of large low-frequency regions with structured boundaries unlike natural image data. We present Compresso, a new compression scheme for label data that outperforms existing approaches by using a sliding window to exploit redundancy across border regions in 2D and 3D. We compare our method to existing compression schemes and provide a detailed evaluation on eleven biomedical and image segmentation datasets. Our method provides a factor of 600–2200x compression for label volumes, with running times suitable for practice.

  8. Compressive CFAR Radar Processing

    OpenAIRE

    Anitori, Laura; Baraniuk, Richard; Maleki, Arian; Otten, Matern; van Rossum, Wim

    2013-01-01

    In this paper we investigate the performance of a combined Compressive Sensing (CS) Constant False Alarm Rate (CFAR) radar processor under different interference scenarios using both the Cell Averaging (CA) and Order Statistic (OS) CFAR detectors. Using the properties of the Complex Approximate Message Passing (CAMP) algorithm, we demonstrate that the behavior of the CFAR processor is independent of the combination with the non-linear recovery and therefore its performance can be predicted us...

  9. Recursive Compressed Sensing

    OpenAIRE

    Freris, Nikolaos M.; Öçal, Orhan; Vetterli, Martin

    2013-01-01

    We introduce a recursive algorithm for performing compressed sensing on streaming data. The approach consists of a) recursive encoding, where we sample the input stream via overlapping windowing and make use of the previous measurement in obtaining the next one, and b) recursive decoding, where the signal estimate from the previous window is utilized in order to achieve faster convergence in an iterative optimization scheme applied to decode the new one. To remove estimation bias, a two-step ...

  10. Universal Compressed Sensing

    OpenAIRE

    Jalali, Shirin; Poor, H. Vincent

    2014-01-01

    In this paper, the problem of developing universal algorithms for compressed sensing of stochastic processes is studied. First, R\\'enyi's notion of information dimension (ID) is generalized to analog stationary processes. This provides a measure of complexity for such processes and is connected to the number of measurements required for their accurate recovery. Then a minimum entropy pursuit (MEP) optimization approach is proposed, and it is proven that it can reliably recover any stationary ...

  11. Kalman Filtered Compressed Sensing

    OpenAIRE

    Vaswani, Namrata

    2008-01-01

    We consider the problem of reconstructing time sequences of spatially sparse signals (with unknown and time-varying sparsity patterns) from a limited number of linear "incoherent" measurements, in real-time. The signals are sparse in some transform domain referred to as the sparsity basis. For a single spatial signal, the solution is provided by Compressed Sensing (CS). The question that we address is, for a sequence of sparse signals, can we do better than CS, if (a) the sparsity pattern of ...

  12. A multiphase compressible model for the simulation of multiphase flows

    International Nuclear Information System (INIS)

    Caltagirone, J.P.; Vincent, St.; Caruyer, C.

    2011-01-01

    A compressible model able to manage incompressible two-phase flows as well as compressible motions is proposed. After a presentation of the multiphase compressible concept, the new model and related numerical methods are detailed on fixed structured grids. The presented model is a 1-fluid model with a reformulated mass conservation equation which takes into account the effects of compressibility. The coupling between pressure and flow velocity is ensured by introducing mass conservation terms in the momentum and energy equations. The numerical model is then validated with four test cases involving the compression of an air bubble by water, the liquid injection in a closed cavity filled with air, a bubble subjected to an ultrasound field and finally the oscillations of a deformed air bubble in melted steel. The numerical results are compared with analytical results and convergence orders in space are provided. (authors)

  13. Scale adaptive compressive tracking.

    Science.gov (United States)

    Zhao, Pengpeng; Cui, Shaohui; Gao, Min; Fang, Dan

    2016-01-01

    Recently, the compressive tracking (CT) method (Zhang et al. in Proceedings of European conference on computer vision, pp 864-877, 2012) has attracted much attention due to its high efficiency, but it cannot well deal with the scale changing objects due to its constant tracking box. To address this issue, in this paper we propose a scale adaptive CT approach, which adaptively adjusts the scale of tracking box with the size variation of the objects. Our method significantly improves CT in three aspects: Firstly, the scale of tracking box is adaptively adjusted according to the size of the objects. Secondly, in the CT method, all the compressive features are supposed independent and equal contribution to the classifier. Actually, different compressive features have different confidence coefficients. In our proposed method, the confidence coefficients of features are computed and used to achieve different contribution to the classifier. Finally, in the CT method, the learning parameter λ is constant, which will result in large tracking drift on the occasion of object occlusion or large scale appearance variation. In our proposed method, a variable learning parameter λ is adopted, which can be adjusted according to the object appearance variation rate. Extensive experiments on the CVPR2013 tracking benchmark demonstrate the superior performance of the proposed method compared to state-of-the-art tracking algorithms.

  14. Compressed sensing electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Leary, Rowan, E-mail: rkl26@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Saghi, Zineb; Midgley, Paul A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Holland, Daniel J. [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom)

    2013-08-15

    The recent mathematical concept of compressed sensing (CS) asserts that a small number of well-chosen measurements can suffice to reconstruct signals that are amenable to sparse or compressible representation. In addition to powerful theoretical results, the principles of CS are being exploited increasingly across a range of experiments to yield substantial performance gains relative to conventional approaches. In this work we describe the application of CS to electron tomography (ET) reconstruction and demonstrate the efficacy of CS–ET with several example studies. Artefacts present in conventional ET reconstructions such as streaking, blurring of object boundaries and elongation are markedly reduced, and robust reconstruction is shown to be possible from far fewer projections than are normally used. The CS–ET approach enables more reliable quantitative analysis of the reconstructions as well as novel 3D studies from extremely limited data. - Highlights: • Compressed sensing (CS) theory and its application to electron tomography (ET) is described. • The practical implementation of CS–ET is outlined and its efficacy demonstrated with examples. • High fidelity tomographic reconstruction is possible from a small number of images. • The CS–ET reconstructions can be more reliably segmented and analysed quantitatively. • CS–ET is applicable to different image content by choice of an appropriate sparsifying transform.

  15. Author Details

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    Egboh, SHO. Vol 8, No 5 (2014) - Articles The reinforcing potentials of Velvet tamarind seed shell as filler in natural rubber compounds. Abstract PDF · Vol 9, No 2 (2015) - Articles Calamus deerratus fibre reinforced natural rubber vulcanizates. Abstract PDF. ISSN: 1997-342X. AJOL African Journals Online. HOW TO USE ...

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    Dynamic Modeling of Natural Convection Solar Energy Collectors for Agricultural Driers I: Theory and Complete Run of the Solutions to the Dynamic Model Equations of SSSCA Flat Plate Collector Abstract PDF · Vol 26, No 2 (2007) - Research papers. Dynamic Modeling of Natural Convection Solar Energy Flat Plate ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Singh, J. Vol 3, No 2 (2011) - Articles Plane waves in a rotating generalized thermo-elastic solid with voids. Abstract PDF. ISSN: 2141-2839. AJOL African Journals Online. HOW TO USE AJOL.

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Vol 12 (2008) - Articles On the wave equations of shallow water with rough bottom topography. Abstract · Vol 14 (2009) - Articles Energy generation in a plant due to variable sunlight intensity

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Iliopsoas haematoma in a rugby player. Abstract PDF · Vol 29, No 1 (2017) - Articles The use of negative pressure wave treatment in athlete recovery. Abstract PDF. ISSN: 2078-516X. AJOL African ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Ismail, A. Vol 9, No 3S (2017): Special Issue - Articles Investigate of wave absorption performance for oil palm frond and empty fruit bunch at 5.8 GHz. Abstract PDF · Vol 9, No 3S (2017): Special Issue ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Isa, M.F.M.. Vol 9, No 3S (2017): Special Issue - Articles Experimental and numerical investigation on blast wave propagation in soil structure. Abstract PDF · Vol 9, No 3S (2017): Special Issue - ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Uptake of intermittent preventive therapy in pregnancy for malaria in Zimbabwe 2013-2015 Audit Abstract. ISSN: 0008-9176. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

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    Adu, M R. Vol 5, No 1 (2006) - Articles The ill effect of outages on National Electric Power Authority (NEPA): Ilorin 132/33kv substation as a case study. Abstract. ISSN: 1596-292X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

  4. Compressive Strength of Compacted Clay-Sand Mixes

    Directory of Open Access Journals (Sweden)

    Faseel Suleman Khan

    2014-01-01

    Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

  5. Compressed digital holography: from micro towards macro

    Science.gov (United States)

    Schretter, Colas; Bettens, Stijn; Blinder, David; Pesquet-Popescu, Béatrice; Cagnazzo, Marco; Dufaux, Frédéric; Schelkens, Peter

    2016-09-01

    signal processing methods from software-driven computer engineering and applied mathematics. The compressed sensing theory in particular established a practical framework for reconstructing the scene content using few linear combinations of complex measurements and a sparse prior for regularizing the solution. Compressed sensing found direct applications in digital holography for microscopy. Indeed, the wave propagation phenomenon in free space mixes in a natural way the spatial distribution of point sources from the 3-dimensional scene. As the 3-dimensional scene is mapped to a 2-dimensional hologram, the hologram samples form a compressed representation of the scene as well. This overview paper discusses contributions in the field of compressed digital holography at the micro scale. Then, an outreach on future extensions towards the real-size macro scale is discussed. Thanks to advances in sensor technologies, increasing computing power and the recent improvements in sparse digital signal processing, holographic modalities are on the verge of practical high-quality visualization at a macroscopic scale where much higher resolution holograms must be acquired and processed on the computer.

  6. Performance evaluation of breast image compression techniques

    International Nuclear Information System (INIS)

    Anastassopoulos, G.; Lymberopoulos, D.; Panayiotakis, G.; Bezerianos, A.

    1994-01-01

    Novel diagnosis orienting tele working systems manipulate, store, and process medical data through real time communication - conferencing schemes. One of the most important factors affecting the performance of these systems is image handling. Compression algorithms can be applied to the medical images, in order to minimize : a) the volume of data to be stored in the database, b) the demanded bandwidth from the network, c) the transmission costs, and to minimize the speed of the transmitted data. In this paper an estimation of all the factors of the process that affect the presentation of breast images is made, from the time the images are produced from a modality, till the compressed images are stored, or transmitted in a Broadband network (e.g. B-ISDN). The images used were scanned images of the TOR(MAX) Leeds breast phantom, as well as typical breast images. A comparison of seven compression techniques has been done, based on objective criteria such as Mean Square Error (MSE), resolution, contrast, etc. The user can choose the appropriate compression ratio in order to achieve the desired image quality. (authors)

  7. Bunch compression for an FEL at NLCTA

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1997-04-01

    As part of the design effort for a free electron laser driven by the Next Linear Collider Test Accelerator (NLCTA), the author reports studies of bunch-length compression utilizing the existing infrastructure and hardware. In one possible version of the NLCTA FEL, bunches with 900-microm FWHM length, generated by an S-band photo-injector, would be compressed to an rms length of 60--120 microm before entering the FEL undulator. It is shown that, using the present magnetic chicane, the bunch compression is essentially straightforward, and that almost all emittance-diluting effects, e.g. wakefields, chromaticity, or space charge in the bending magnets, are small. The only exception to this finding is the predicted increase of the horizontal emittance due to coherent synchrotron radiation (CSR). Estimates based on existing theories of coherent synchrotron radiation suggest a tripling or quadrupling of the initial emittance, which seems to preclude bunch compression during regular FEL operation. Serendipitously, the magnitude of the predicted emittance growth would, on the other hand, make the NLCTA chicane an excellent tool for measuring the effects of coherent synchrotron radiation. This will be of considerable interest to many future projects, in particular to the Linac Coherent Light Source (LCLS). As an aside, it is shown that coherent synchrotron radiation in a bending magnet gives rise to a minimum possible bunch length, which is very reminiscent of the Oide limit on the vertical spot size at the interaction point of a linear collider

  8. A study of compressed breast thickness at Hirosaki University Hospital

    International Nuclear Information System (INIS)

    Kon, Masanori; Osanai, Tsunemi; Ootani, Yuhiko; Sugawara, Kaoru; Abe, Katsumi

    2000-01-01

    Evaluation of image quality and medical exposure dose is very important in mammography. However, the standard compressed breast thickness of Japanese women is uncertain. Authors therefore analyzed compressed breast thickness on bilateral cephalocaudal and mediolateral oblique radiographs of 3445 women who underwent mammography between June 5, 1989 and December 7, 1998. The total average compressed breast thickness was about 10 mm less than the thickness of the American College of Radiography (ACR) standard mammographic accreditation phantom. It therefore appears necessary to establish a Japanese standard for the phantom to evaluate image quality and medical exposure dose accurately in Japanese women. (K.H.)

  9. Compression of toroidal plasma by imploding plasma-liner

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1979-07-01

    A new concept of compressing a plasma in a closed magnetic configuration by a version of liner implosion flux compression technique is considered. The liner consists of a dense plasma cylinder, i.e. the plasma-liner. Maximum compression ratio of toroidal plasma is determined just by the initial density ratio of the toroidal plasma to the liner plasma because of the Rayleigh-Taylor instability. A start-up senario of plasma-liner is also proposed with a possible application of this concept to the creation of a burning plasma in reversed field configurations, i.e. burning plasma vortex. (author)

  10. Electrical properties of Egyptian natural graphite

    International Nuclear Information System (INIS)

    El-Shazly, O.; El-Wahidy, E.F.; Elanany, N.; Saad, N.A.

    1992-06-01

    The electrical properties of Egyptian natural graphite flakes, obtained from the graphite schists of Wadi Bent, Eastern Desert, were measured. The flakes were ground and compressed into pellets. The standard four probe dc method was used to measure the temperature dependence of the electric resistivity from room temperature down to 12 K. The transverse and longitudinal magnetoresistance were measured in the low magnetic field range at temperatures 300 K, 77 K and 12 K. The transverse magnetoresistance data was used to estimate the average mobility, assuming a simple two-band model. (author). 20 refs, 4 figs, 1 tab

  11. Application of plasma focus device to compression of toroidal plasma

    International Nuclear Information System (INIS)

    Ikuta, Kazunari

    1980-01-01

    A new concept of compressing a toroidal plasma using a plasma focus device is considered. Maximum compression ratio of toroidal plasma is determined merely by the initial density ratio of the toroidal plasma to a sheet plasma in a focus device because of the Rayleigh-Taylor instability. An initiation senario of plasma-linear is also proposed with a possible application of this concepts to the creation of a burning plasma in reversed field configurations, i.e., burning plasma vortex. (author)

  12. Mammographic compression in Asian women.

    Directory of Open Access Journals (Sweden)

    Susie Lau

    Full Text Available To investigate: (1 the variability of mammographic compression parameters amongst Asian women; and (2 the effects of reducing compression force on image quality and mean glandular dose (MGD in Asian women based on phantom study.We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD measurement software (Volpara to assess compression force, compression pressure, compressed breast thickness (CBT, breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA slabs.Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (p0.05.Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD.

  13. Mammographic compression in Asian women

    Science.gov (United States)

    Lau, Susie; Abdul Aziz, Yang Faridah; Ng, Kwan Hoong

    2017-01-01

    Objectives To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study. Methods We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35–80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA) slabs. Results Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (p0.05). Conclusions Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD. PMID:28419125

  14. Compressive Transient Imaging

    KAUST Repository

    Sun, Qilin

    2017-04-01

    High resolution transient/3D imaging technology is of high interest in both scientific research and commercial application. Nowadays, all of the transient imaging methods suffer from low resolution or time consuming mechanical scanning. We proposed a new method based on TCSPC and Compressive Sensing to achieve a high resolution transient imaging with a several seconds capturing process. Picosecond laser sends a serious of equal interval pulse while synchronized SPAD camera\\'s detecting gate window has a precise phase delay at each cycle. After capturing enough points, we are able to make up a whole signal. By inserting a DMD device into the system, we are able to modulate all the frames of data using binary random patterns to reconstruct a super resolution transient/3D image later. Because the low fill factor of SPAD sensor will make a compressive sensing scenario ill-conditioned, We designed and fabricated a diffractive microlens array. We proposed a new CS reconstruction algorithm which is able to denoise at the same time for the measurements suffering from Poisson noise. Instead of a single SPAD senor, we chose a SPAD array because it can drastically reduce the requirement for the number of measurements and its reconstruction time. Further more, it not easy to reconstruct a high resolution image with only one single sensor while for an array, it just needs to reconstruct small patches and a few measurements. In this thesis, we evaluated the reconstruction methods using both clean measurements and the version corrupted by Poisson noise. The results show how the integration over the layers influence the image quality and our algorithm works well while the measurements suffer from non-trival Poisson noise. It\\'s a breakthrough in the areas of both transient imaging and compressive sensing.

  15. Nature Detectives

    Science.gov (United States)

    Harr, Natalie; Lee, Richard E.; Jr.

    2010-01-01

    Richard Louv's "Last Child in the Woods" (2008) added to a growing consensus to get children outside and experiencing nature. Using ideas from place-based education, the authors present a simple year-long project that brings science, nature, and other curriculum standards to life right in your school yard. With a focus on journaling, this project…

  16. Relationship between medical compression and intramuscular pressure as an explanation of a compression paradox.

    Science.gov (United States)

    Uhl, J-F; Benigni, J-P; Cornu-Thenard, A; Fournier, J; Blin, E

    2015-06-01

    Using standing magnetic resonance imaging (MRI), we recently showed that medical compression, providing an interface pressure (IP) of 22 mmHg, significantly compressed the deep veins of the leg but not, paradoxically, superficial varicose veins. To provide an explanation for this compression paradox by studying the correlation between the IP exerted by medical compression and intramuscular pressure (IMP). In 10 legs of five healthy subjects, we studied the effects of different IPs on the IMP of the medial gastrocnemius muscle. The IP produced by a cuff manometer was verified by a Picopress® device. The IMP was measured with a 21G needle connected to a manometer. Pressure data were recorded in the prone and standing positions with cuff manometer pressures from 0 to 50 mmHg. In the prone position, an IP of less than 20 did not significantly change the IMP. On the contrary, a perfect linear correlation with the IMP (r = 0.99) was observed with an IP from 20 to 50 mmHg. We found the same correlation in the standing position. We found that an IP of 22 mmHg produced a significant IMP increase from 32 to 54 mmHg, in the standing position. At the same time, the subcutaneous pressure is only provided by the compression device, on healthy subjects. In other words, the subcutaneous pressure plus the IP is only a little higher than 22 mmHg-a pressure which is too low to reduce the caliber of the superficial veins. This is in accordance with our standing MRI 3D anatomical study which showed that, paradoxically, when applying low pressures (IP), the deep veins are compressed while the superficial veins are not. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  17. Author Details

    African Journals Online (AJOL)

    , Levamisole and Ivermectin against gastrointestinal nematode (GIN) infections in goats on natural pastures in Gomba District, Uganda Abstract PDF · Vol 16, No 1 (2015) - Articles Prevalence of common gastro-intestinal nematode infections in ...

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    Rutaceae) in southern Benin in 2008–2009. Abstract PDF · Vol 7, No 2 (2013) - Articles Ovipositional behaviour of two mango fruit fly species (Diptera Tephritidae) in relation to Oecophylla cues (Hymenoptera Formicidae) as compared to natural ...

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    resistance among uropathogens from hospitalised children in Beira, Mozambique Abstract PDF. ISSN: 0256-95749. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Monitoring on Attitudes toward Internet Fraud among Undergraduate Students of Obafemi Awolowo University, Ile-Ife Abstract PDF. ISSN: 2070-0083. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Annelida: Oligochaeta) of forests in Limpopo Province, South Africa: diversity, communities and conservation. Abstract. ISSN: 2224-073X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    functional-narrative\\' model to assist students in preparing postgraduate research proposals. Abstract. ISSN: 1011-3487. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    , Incubators and the Effects of a Spray-Disinfectant - A Quarterly Ammonium Compound Abstract. ISSN: 1116-1043. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    ) antibodies in pregnant women in Anyigba, Kogi State, North Central Nigeria Abstract PDF. ISSN: 1595-689X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    midwives' emic views with regard to experiential learning environment in Limpopo Province, South Africa Abstract. ISSN: 1117-4315. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    methylpentanoate extracted from mushroom Cyptotrama asprata against mosquito Aedes aegypti. Abstract PDF. ISSN: 1997-342X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Bitter kola) in southwest Nigeria: opportunity for development of a biological product. Abstract PDF. ISSN: 1110-6859. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Mutilation in Africa - Articles Psychosocial and sexual aspects of female circumcision. Abstract PDF. ISSN: 1110-5704. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    hyperlipidaemic effects of aqueous stem bark extract of Irvingia gabonensis in streptozotocin-induced diabetic rats. Abstract PDF. ISSN: 0795-8080. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    , happiness, hope and marital satisfaction among married people in Makurdi Metropolis, Nigeria Abstract. ISSN: 1596-9231. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    communication-style and parental neglect as predictors of aggressive tendencies among Secondary School adolescents. Abstract. ISSN: 0189-0263. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    changer: embracing innovation and dynamism in contemporary social work practice in Zimbabwe Abstract PDF. ISSN: 2409-5605. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Induced Incidence of Protection and Aggregate Demand for Imports: Evidence from Malawi Abstract. ISSN: 1116-4875. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Hydrophilic (Hydrogenated Castor Oil-Gum Tragacanth) Matrix using Propranolol Hydrochloride as Test Drug Abstract PDF. ISSN: 1026-552X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Acetylguanacone from Soursop (Annona muricata Linn) Fruit and Molecular Docking Experiments Abstract PDF. ISSN: 1119-8362. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    carnitine supplementation on growth performance, carcass traits and blood parameters of broiler chickens. Abstract PDF. ISSN: 2221-4062. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    carnitine optimal combinations in MPP+- induced cellular model of Parkinson's disease. Abstract PDF. ISSN: 0795-8080. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    based intrusion detection system: A cost effective tool for managing intrusion detection. Abstract. ISSN: 1118-1931. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  19. Author Affiliations

    Indian Academy of Sciences (India)

    sadh/034/01/0001-0002. Author Affiliations. Raja Natarajan1. School of Technology and Computer Science, Tata Institute of Fundamental Research, Mumbai 400 005. Sadhana. Current Issue : Vol. 43, Issue 1 · Current Issue Volume 43 | Issue ...

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    based weaning foods fortified with legumes: factors affecting their availability and competitiveness in accra, ghana. Abstract PDF. ISSN: 1684-5374. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    modernity': revisiting the works of the independence decade in modern Nigerian art. Abstract PDF. ISSN: 2346-7126. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Dried Esomeprazole Magnesium Microspheres Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

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    509X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES.

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    adipogenic effects of slendesta, standard potato extracts containing 5% protease inhibitor II Abstract PDF. ISSN: 0189-6016. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Consumption' among undergraduate students of Economics in Ambrose Alli University, Ekpoma Abstract PDF. ISSN: 2070-0083. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Specific Health-Related Quality of Life Among Nigerians with Parkinson's Disease Abstract PDF. ISSN: 1597-4292. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Saccharomyces cerevisiae) on the growth and body composition of Heterobranchus longifilis fingerlings. Abstract. ISSN: 1596-972X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    ” Passages in the Context of Homosexuality Controversy: A Nigerian Perspective Abstract PDF. ISSN: 2141-7040. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    chimique des fruits de quatre essences locales : vitex doniana sweet, vitex madiensis oliv. olax subscorpioides oliv. et ximenia americana. Details PDF · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  10. Analysis by compression

    DEFF Research Database (Denmark)

    Meredith, David

    MEL is a geometric music encoding language designed to allow for musical objects to be encoded parsimoniously as sets of points in pitch-time space, generated by performing geometric transformations on component patterns. MEL has been implemented in Java and coupled with the SIATEC pattern discov...... discovery algorithm to allow for compact encodings to be generated automatically from in extenso note lists. The MEL-SIATEC system is founded on the belief that music analysis and music perception can be modelled as the compression of in extenso descriptions of musical objects....

  11. Compressive full waveform lidar

    Science.gov (United States)

    Yang, Weiyi; Ke, Jun

    2017-05-01

    To avoid high bandwidth detector, fast speed A/D converter, and large size memory disk, a compressive full waveform LIDAR system, which uses a temporally modulated laser instead of a pulsed laser, is studied in this paper. Full waveform data from NEON (National Ecological Observatory Network) are used. Random binary patterns are used to modulate the source. To achieve 0.15 m ranging resolution, a 100 MSPS A/D converter is assumed to make measurements. SPIRAL algorithm with canonical basis is employed when Poisson noise is considered in the low illuminated condition.

  12. Compression test apparatus

    Science.gov (United States)

    Shanks, G. C. (Inventor)

    1981-01-01

    An apparatus for compressive testing of a test specimen may comprise vertically spaced upper and lower platen members between which a test specimen may be placed. The platen members are supported by a fixed support assembly. A load indicator is interposed between the upper platen member and the support assembly for supporting the total weight of the upper platen member and any additional weight which may be placed on it. Operating means are provided for moving the lower platen member upwardly toward the upper platen member whereby an increasing portion of the total weight is transferred from the load indicator to the test specimen.

  13. Compressive Fatigue in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben

    1999-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Small clear specimens of spruce are taken to failure in square wave formed fatigue loading at a stress excitation level corresponding to 80% of the short term strength. Four...... frequencies ranging from 0.01 Hz to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation...

  14. Metal Hydride Compression

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bowman, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Barton [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Anovitz, Lawrence [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jensen, Craig [Hawaii Hydrogen Carriers LLC, Honolulu, HI (United States)

    2017-07-01

    Conventional hydrogen compressors often contribute over half of the cost of hydrogen stations, have poor reliability, and have insufficient flow rates for a mature FCEV market. Fatigue associated with their moving parts including cracking of diaphragms and failure of seal leads to failure in conventional compressors, which is exacerbated by the repeated starts and stops expected at fueling stations. Furthermore, the conventional lubrication of these compressors with oil is generally unacceptable at fueling stations due to potential fuel contamination. Metal hydride (MH) technology offers a very good alternative to both conventional (mechanical) and newly developed (electrochemical, ionic liquid pistons) methods of hydrogen compression. Advantages of MH compression include simplicity in design and operation, absence of moving parts, compactness, safety and reliability, and the possibility to utilize waste industrial heat to power the compressor. Beyond conventional H2 supplies of pipelines or tanker trucks, another attractive scenario is the on-site generating, pressuring and delivering pure H2 at pressure (≥ 875 bar) for refueling vehicles at electrolysis, wind, or solar generating production facilities in distributed locations that are too remote or widely distributed for cost effective bulk transport. MH hydrogen compression utilizes a reversible heat-driven interaction of a hydride-forming metal alloy with hydrogen gas to form the MH phase and is a promising process for hydrogen energy applications [1,2]. To deliver hydrogen continuously, each stage of the compressor must consist of multiple MH beds with synchronized hydrogenation & dehydrogenation cycles. Multistage pressurization allows achievement of greater compression ratios using reduced temperature swings compared to single stage compressors. The objectives of this project are to investigate and demonstrate on a laboratory scale a two-stage MH hydrogen (H2) gas compressor with a

  15. Microbuckling compression failure of a radiation-induced wood/polymer composite

    International Nuclear Information System (INIS)

    Boey, F.Y.C.

    1990-01-01

    A wood/polymer composite was produced by impregnating Ramin wood with methyl methacrylate monomer and subsequently polymerizing it by gamma irradiation. To assess the improvement in compression strength of the wood caused by the polymer impregnation, a microbuckling compression failure mechanism was used to model the compression failure of the composite. Such a mechanism was found to predict a linear relationship between the compression strength and the percentage polymer impregnation (by weight). Uniaxial compression test results at 45(±5)% and 90(±5)% relative humidity levels, after being statistically analysed, showed that such a linear relationship was valid for up to 100% polymer impregnation. (author)

  16. Energy transfer in compressible turbulence

    Science.gov (United States)

    Bataille, Francoise; Zhou, YE; Bertoglio, Jean-Pierre

    1995-01-01

    This letter investigates the compressible energy transfer process. We extend a methodology developed originally for incompressible turbulence and use databases from numerical simulations of a weak compressible turbulence based on Eddy-Damped-Quasi-Normal-Markovian (EDQNM) closure. In order to analyze the compressible mode directly, the well known Helmholtz decomposition is used. While the compressible component has very little influence on the solenoidal part, we found that almost all of the compressible turbulence energy is received from its solenoidal counterpart. We focus on the most fundamental building block of the energy transfer process, the triadic interactions. This analysis leads us to conclude that, at low turbulent Mach number, the compressible energy transfer process is dominated by a local radiative transfer (absorption) in both inertial and energy containing ranges.

  17. Compressive sensing in medical imaging.

    Science.gov (United States)

    Graff, Christian G; Sidky, Emil Y

    2015-03-10

    The promise of compressive sensing, exploitation of compressibility to achieve high quality image reconstructions with less data, has attracted a great deal of attention in the medical imaging community. At the Compressed Sensing Incubator meeting held in April 2014 at OSA Headquarters in Washington, DC, presentations were given summarizing some of the research efforts ongoing in compressive sensing for x-ray computed tomography and magnetic resonance imaging systems. This article provides an expanded version of these presentations. Sparsity-exploiting reconstruction algorithms that have gained popularity in the medical imaging community are studied, and examples of clinical applications that could benefit from compressive sensing ideas are provided. The current and potential future impact of compressive sensing on the medical imaging field is discussed.

  18. Fingerprints in Compressed Strings

    DEFF Research Database (Denmark)

    Bille, Philip; Cording, Patrick Hagge; Gørtz, Inge Li

    2013-01-01

    The Karp-Rabin fingerprint of a string is a type of hash value that due to its strong properties has been used in many string algorithms. In this paper we show how to construct a data structure for a string S of size N compressed by a context-free grammar of size n that answers fingerprint queries....... That is, given indices i and j, the answer to a query is the fingerprint of the substring S[i,j]. We present the first O(n) space data structures that answer fingerprint queries without decompressing any characters. For Straight Line Programs (SLP) we get O(logN) query time, and for Linear SLPs (an SLP...... derivative that captures LZ78 compression and its variations) we get O(loglogN) query time. Hence, our data structures has the same time and space complexity as for random access in SLPs. We utilize the fingerprint data structures to solve the longest common extension problem in query time O(logNlogℓ) and O...

  19. Respiratory sounds compression.

    Science.gov (United States)

    Yadollahi, Azadeh; Moussavi, Zahra

    2008-04-01

    Recently, with the advances in digital signal processing, compression of biomedical signals has received great attention for telemedicine applications. In this paper, an adaptive transform coding-based method for compression of respiratory and swallowing sounds is proposed. Using special characteristics of respiratory sounds, the recorded signals are divided into stationary and nonstationary portions, and two different bit allocation methods (BAMs) are designed for each portion. The method was applied to the data of 12 subjects and its performance in terms of overall signal-to-noise ratio (SNR) values was calculated at different bit rates. The performance of different quantizers was also considered and the sensitivity of the quantizers to initial conditions has been alleviated. In addition, the fuzzy clustering method was examined for classifying the signal into different numbers of clusters and investigating the performance of the adaptive BAM with increasing the number of classes. Furthermore, the effects of assigning different numbers of bits for encoding stationary and nonstationary portions of the signal were studied. The adaptive BAM with variable number of bits was found to improve the SNR values of the fixed BAM by 5 dB. Last, the possibility of removing the training part for finding the parameters of adaptive BAMs for each individual was investigated. The results indicate that it is possible to use a predefined set of BAMs for all subjects and remove the training part completely. Moreover, the method is fast enough to be implemented for real-time application.

  20. Compressive Sensing DNA Microarrays

    Directory of Open Access Journals (Sweden)

    Sheikh Mona A

    2009-01-01

    Full Text Available Compressive sensing microarrays (CSMs are DNA-based sensors that operate using group testing and compressive sensing (CS principles. In contrast to conventional DNA microarrays, in which each genetic sensor is designed to respond to a single target, in a CSM, each sensor responds to a set of targets. We study the problem of designing CSMs that simultaneously account for both the constraints from CS theory and the biochemistry of probe-target DNA hybridization. An appropriate cross-hybridization model is proposed for CSMs, and several methods are developed for probe design and CS signal recovery based on the new model. Lab experiments suggest that in order to achieve accurate hybridization profiling, consensus probe sequences are required to have sequence homology of at least 80% with all targets to be detected. Furthermore, out-of-equilibrium datasets are usually as accurate as those obtained from equilibrium conditions. Consequently, one can use CSMs in applications in which only short hybridization times are allowed.

  1. Spinal cord compression--an oncologic emergency.

    Science.gov (United States)

    Frank, A R

    1990-08-01

    Spinal cord compression secondary to epidural metastatic tumor is an emergency clinical situation that requires prompt diagnosis and treatment if permanent neurologic damage is to be prevented. Physicians caring for patients with cancer must maintain a high index of suspicion for this problem. Back pain is a common clinical situation in the general population but in the cancer patient, one should consider this sign indicative of possible spinal cord compression even though a long tumor-free interval has occurred since the original diagnosis of neoplasm. The diagnosis is established by thorough neurologic examination, plain x-rays, myelography, CT and MRI scanning. Once the diagnosis is established, treatment is instituted with steroids, decompressive surgery and postoperative irradiation or external irradiation alone depending upon the emergent nature of the clinical situation. Regardless of the initial treatment, patients with spinal cord compression require management in a multi-disciplinary fashion. Early therapy will result in the best relief of symptoms and maintenance of the ability to walk. The ultimate prognosis of such patients is very dismal in view of the metastatic nature of their disease but prompt diagnosis and treatment is necessary to prevent devastating sequelae for the patients and their families.

  2. Information optimal compressive sensing: static measurement design.

    Science.gov (United States)

    Ashok, Amit; Huang, Liang-Chih; Neifeld, Mark A

    2013-05-01

    The compressive sensing paradigm exploits the inherent sparsity/compressibility of signals to reduce the number of measurements required for reliable reconstruction/recovery. In many applications additional prior information beyond signal sparsity, such as structure in sparsity, is available, and current efforts are mainly limited to exploiting that information exclusively in the signal reconstruction problem. In this work, we describe an information-theoretic framework that incorporates the additional prior information as well as appropriate measurement constraints in the design of compressive measurements. Using a Gaussian binomial mixture prior we design and analyze the performance of optimized projections relative to random projections under two specific design constraints and different operating measurement signal-to-noise ratio (SNR) regimes. We find that the information-optimized designs yield significant, in some cases nearly an order of magnitude, improvements in the reconstruction performance with respect to the random projections. These improvements are especially notable in the low measurement SNR regime where the energy-efficient design of optimized projections is most advantageous. In such cases, the optimized projection design departs significantly from random projections in terms of their incoherence with the representation basis. In fact, we find that the maximizing incoherence of projections with the representation basis is not necessarily optimal in the presence of additional prior information and finite measurement noise/error. We also apply the information-optimized projections to the compressive image formation problem for natural scenes, and the improved visual quality of reconstructed images with respect to random projections and other compressive measurement design affirms the overall effectiveness of the information-theoretic design framework.

  3. 1999 Annual report: compression + power + service

    International Nuclear Information System (INIS)

    2000-01-01

    Enerflex manufactures, services and leases compression systems for the production and processing of natural gas and gas-fueled power generation systems. Design, engineering, project management, financing, installation commissioning and after-sales service are also part of Enerflex's arsenal of tools to ensure innovation, and high standards of quality and service. In 1999, Enerflex suffered an 18 per cent decline in revenues from $315 million in 1998 to $257 million in 1999, entirely due to lower sales of big ticket compression equipment in Canada. At the same time, revenues from international sales and service increased to $ 61.8 million in 1999, from $ 53 million in 1998. The company successfully completed the move to a new 328,000 sq. ft state-of-the-art manufacturing facility, and made its first significant sale to the United States in 1999 in the form of delivering a coal bed methane project in the Powder River area of Wyoming, and power generation equipment to Massachusetts. Although in the short term unusually warm average temperatures, industry cash flows, and access to capital may determine demand for the company's products and services, the long-term fundamentals are positive and demand for compression equipment and power generation systems is likely to grow. Indeed, in the fourth quarter of 1999, market conditions improved significantly and the company recorded its highest quarterly revenues and earnings during the last quarter. The annual review provides further details about the operations of the company's various divisions, (Compression and Power Systems, Parts and Compression Services, Leasing and Financing), management's review of the company's overall operations and finances, audited financial statements, and shareholders' information

  4. Introduction to compressible fluid flow

    CERN Document Server

    Oosthuizen, Patrick H

    2013-01-01

    IntroductionThe Equations of Steady One-Dimensional Compressible FlowSome Fundamental Aspects of Compressible FlowOne-Dimensional Isentropic FlowNormal Shock WavesOblique Shock WavesExpansion Waves - Prandtl-Meyer FlowVariable Area FlowsAdiabatic Flow with FrictionFlow with Heat TransferLinearized Analysis of Two-Dimensional Compressible FlowsHypersonic and High-Temperature FlowsHigh-Temperature Gas EffectsLow-Density FlowsBibliographyAppendices

  5. Mammographic compression in Asian women.

    Science.gov (United States)

    Lau, Susie; Abdul Aziz, Yang Faridah; Ng, Kwan Hoong

    2017-01-01

    To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study. We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA) slabs. Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (pAsian women. The median compression force should be about 8.1 daN compared to the current 12.0 daN. Decreasing compression force from 12.0 daN to 9.0 daN increased CBT by 3.3±1.4 mm, MGD by 6.2-11.0%, and caused no significant effects on image quality (p>0.05). Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD.

  6. Kyphoplasty for severe osteoporotic vertebral compression fractures

    International Nuclear Information System (INIS)

    Bao Zhaohua; Wang Genlin; Yang Huilin; Meng Bin; Chen Kangwu; Jiang Weimin

    2010-01-01

    Objective: To evaluate the clininal efficacy of kyphoplasty for severe osteoporotic vertebral compression fractures. Methods: Forty-five patients with severe osteoporotic compressive fractures were treated by kyphoplasty from Jan 2005 to Jan 2009. The compressive rate of the fractured vertebral bodies was more than 75%. According to the morphology of the vertebral compression fracture bodies the unilateral or bilateral balloon kyphoplasty were selected. The anterior vertebral height was measured on a standing lateral radiograph at pre-operative, post-operative (one day after operation) and final follow-up time. A visual analog scale(VAS) and the Oswestry disability index (ODI) were chosen to evaluate pain status and functional activity. Results: The mean follow-up was for 21.7 months (in range from 18 to 48 months). The anterior vertebral body height of fracture vertebra was restored from preoperative (18.7 ± 3.1)% to postoperative (51.4 ± 2.3)%, the follow-up period (50.2 ± 2.7)%. There was a significant improvement between preoperative and postoperative values (P 0.05). The VAS was 8.1 ± 1.4 at preoperative, 2.6 ± 0.9 at postoperative, 2.1 ± 0.5 at final follow-up time; and the ODI was preoperative 91.1 ± 2.3, postoperative 30.7 ± 7.1, follow-up period 26.1 ± 5.1. There was statistically significant improvement in the VAS and ODI in the post-operative assessment compared with the pre-operative assessment (P 0.05). Asymptomatic cement leakage occurred in three cases. New vertebral fracture occurred in one case. Conclusion: The study suggests that balloon kyphoplasty is a safe and effective procedure in the treatment of severe osteoporotic vertebral compression fractures. (authors)

  7. Adiabatic compression and radiative compression of magnetic fields

    International Nuclear Information System (INIS)

    Woods, C.H.

    1980-01-01

    Flux is conserved during mechanical compression of magnetic fields for both nonrelativistic and relativistic compressors. However, the relativistic compressor generates radiation, which can carry up to twice the energy content of the magnetic field compressed adiabatically. The radiation may be either confined or allowed to escape

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    Razali, S. Vol 9, No 5S (2017): Special Issue - Articles Performance of Multiple Error Correction (MEC) scheme based Hybrid ARQ (HARQ) algorithm for maximizing lifetime of Wireless Sensor Network (WSN) for natural disaster monitoring. Abstract PDF. ISSN: 1112-9867. AJOL African Journals Online. HOW TO USE AJOL.

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    Amin, N.A.M.. Vol 9, No 3S (2017): Special Issue - Articles Dissolved Gas Analysis (DGA) of natural ester oils under arcing faults. Abstract PDF · Vol 9, No 3S (2017): Special Issue - Articles Lightning impulse investigation on vegetables oils and simulation of electric field distribution. Abstract PDF. ISSN: 1112-9867.

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    actual reason for the motion of gas in sunspots is not yet clearly understood, because the interplay between magnetic and other forces on hot matter is still a topic of research. In addition, continuing with our Darwininan theme for this year, there is an article on the unit of natural selection that not only raises interesting ...

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    the behaviour of the abstract Mendelian factors of heredity ushered in the new discipline of cytogenetics. One person who contributed more than anyone else in this synthesis was Walter. Sutton, who is featured in this issue of Resonance. The laws of heredity also provided the missing link in the theory of evolution by natural ...

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    Ashour, MM. Vol 12, No 4 (2000) - Articles ROLE OF DIAGNOSTIC LAPAROSCOPY IN OBSCURE ASCITES Details. ISSN: 1110-5607. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    Masoud, M. Vol 12, No 4 (2000) - Articles ROLE OF DIAGNOSTIC LAPAROSCOPY IN OBSCURE ASCITES Details. ISSN: 1110-5607. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    Ilenikhena, P. A. Vol 2 (2003) - Articles Solution Grotwh, Characterization and Possible Applications of Beryllium Fluoride (BeF2) Thin Films Deposited at 320K and at pH of 7 - 12. Abstract PDF. ISSN: 1596-0862. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Akah, P.A. Vol 2, No 1 (2009) - Articles Gastro-protective effects of the leaf extract and fractions of fleurya aestuans l (urticaceae) Abstract PDF. ISSN: 1596-9819. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

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    Akpan, P A. Vol 6, No 1 (2007) - Articles Pathology of experimental Escherichia coli infection in mice: a laboratory animal model for research in Matitis complex. Abstract PDF. ISSN: 1596-2911. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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