Harvesting and replenishment policies for renewable natural resources

Science.gov (United States)

Douglas, Aaron J.; Johnson, Richard L.

1993-01-01

The current paper links the optimal intertemporal use of renewable natural resources to the harvesting activities of various economic agents. Previous contributions cite market forces as a causative factor inducing the extirpation of renewable natural resources. The analysis given here discusses investment in the stock of renewable resources and cites important examples of this activity. By introducing joint harvesting and replenishment strategies into a model of renewable resource use, the analysis adds descriptive reality and relevance to positive and normative discussions of renewable natural resource use. A high price for the yield or a high discount rate tend to diminish the size of the optimum stationary stock of the resource with a non-replenishment harvesting strategy. Optimal non-replenishment harvesting strategies for renewable natural resources will exhaustion or extirpation of the resource if the price of the yield or the discount rate are sufficiently large. However, the availability of a replenishment technology and the use of replenishment activities tends to buffer the resource against exhaustion or extirpation.

Suboptimal and optimal order policies for fixed and varying replenishment interval with declining market

Science.gov (United States)

Yu, Jonas C. P.; Wee, H. M.; Yang, P. C.; Wu, Simon

2016-06-01

One of the supply chain risks for hi-tech products is the result of rapid technological innovation; it results in a significant decline in the selling price and demand after the initial launch period. Hi-tech products include computers and communication consumer's products. From a practical standpoint, a more realistic replenishment policy is needed to consider the impact of risks; especially when some portions of shortages are lost. In this paper, suboptimal and optimal order policies with partial backordering are developed for a buyer when the component cost, the selling price, and the demand rate decline at a continuous rate. Two mathematical models are derived and discussed: one model has the suboptimal solution with the fixed replenishment interval and a simpler computational process; the other one has the optimal solution with the varying replenishment interval and a more complicated computational process. The second model results in more profit. Numerical examples are provided to illustrate the two replenishment models. Sensitivity analysis is carried out to investigate the relationship between the parameters and the net profit.

Mechanistic Modeling of Water Replenishment Rate of Zeer Refrigerator

Directory of Open Access Journals (Sweden)

B. N. Nwankwojike

2017-06-01

Full Text Available A model for predicting the water replenishment rate of zeer pot refrigerator was developed in this study using mechanistic modeling approach and evaluated at Obowo, Imo State, Nigeria using six fruits, tomatoes, guava, okra, banana, orange and avocado pear. The developed model confirmed zeer pot water replenishment rate as a function of ambient temperature, relative humidity, wind speed, thermal conductivity of the pot materials and sand, density of air and water vapor, permeability coefficient of clay and heat transfer coefficient of water into air, circumferential length, height of pot, geometrical profile of the pot, heat load of the food preserved, heat flow into the device and gradient at which the pot is placed above ground level. Compared to the conventional approach of water replenishment, performance analysis results revealed 44% to 58% water economy when the zeer pot’s water was replenished based on the model’s prediction; while there was no significant difference in the shelf-life of the fruits preserved with both replenishment methods. Application of the developed water replenishment model facilitates optimal water usage in this system, thereby reducing operational cost of zeer pot refrigerator.

Establishment of vesicular-arbuscular mycorrhizal fungi and other microorganisms on a beach replenishment site in Florida.

Science.gov (United States)

Sylvia, D M; Will, M E

1988-02-01

Beach replenishment is a widely used method of controlling coastal erosion. To reduce erosional losses from wind, beach grasses are often planted on the replenishment sands. However, there is little information on the microbial populations in this material that may affect plant establishment and growth. The objectives of this research were to document changes in the populations of vesicular-arbuscular mycorrhizal (VAM) fungi and other soil microorganisms in replenishment materials and to determine whether roots of transplanted beach grasses become colonized by beneficial microbes. The study was conducted over a 2-year period on a replenishment project in northeastern Florida. Three sampling locations were established at 1-km intervals along the beach. Each location consisted of three plots: an established dune, replenishment sand planted with Uniola paniculata and Panicum sp., and replenishment sand left unplanted. Fungal and bacterial populations increased rapidly in the rhizosphere of beach grasses in the planted plots. However, no bacteria were recovered that could fix significant amounts of N(2). The VAM fungi established slowly on the transplanted grasses. Even after two growing seasons, levels of root colonization and sporulation were significantly below those found in the established dune. There was a shift in the dominant VAM fungi found in the planted zone with respect to those in the established dunes. The most abundant species recovered from the established dunes were Glomus deserticola, followed by Acaulospora scrobiculata and Scutellospora weresubiae. The VAM fungi that colonized the planted zone most rapidly were Glomus globiferum, followed by G. deserticola and Glomus aggregatum.

A novel multi-item joint replenishment problem considering multiple type discounts.

Directory of Open Access Journals (Sweden)

Ligang Cui

Full Text Available In business replenishment, discount offers of multi-item may either provide different discount schedules with a single discount type, or provide schedules with multiple discount types. The paper investigates the joint effects of multiple discount schemes on the decisions of multi-item joint replenishment. In this paper, a joint replenishment problem (JRP model, considering three discount (all-unit discount, incremental discount, total volume discount offers simultaneously, is constructed to determine the basic cycle time and joint replenishment frequencies of multi-item. To solve the proposed problem, a heuristic algorithm is proposed to find the optimal solutions and the corresponding total cost of the JRP model. Numerical experiment is performed to test the algorithm and the computational results of JRPs under different discount combinations show different significance in the replenishment cost reduction.

Gas-ion laser with gas pressure maintenance means

International Nuclear Information System (INIS)

Thatcher, J.B.

1975-01-01

A gas-ion laser is described including means to maintain the ionizable gas in the laser cavity at a rather constant pressure over an extended period of time to significantly increase the useful life of the gas-ion laser. The gas laser includes a gas makeup system having a high pressure source or storage container and a regulating valve. The valve has a permeable solid state orifice member through which the gas flows from the high pressure source to the laser cavity to replenish the gas in the laser cavity and maintain the gas pressure in the cavity rather constant. The permeable orifice member is selected from a solid state material having a permeability that is variable in relation to the magnitude of the energy applied to the orifice member. The gas-ion laser has a valve operating means such as a heater for varying the applied energy such as thermal energy to the member to regulate the gas flow. Additionally, the gas-ion laser has a valve control means that is responsive to the gas pressure in the laser cavity for controlling the valve control means to maintain the pressure at a desired level. (U.S.)

ARTICLES: Stabilization of the composition of the gaseous medium in a pulse-periodic CO2 laser by hopcalite

Science.gov (United States)

Baranov, V. Yu; Drokov, G. F.; Kuz'menko, V. A.; Mezhevov, V. S.; Pigul'skaya, V. V.

1986-05-01

The results of experiments on using hopcalite to stabilize the gas mixture composition in pulse-periodic and single-pulse CO2 lasers are reported. A study was made of the reasons for a fall in the activity of the catalyst with time under typical CO2 laser conditions and a catalyst regeneration regime was selected. The use of hopcalite ensured prolonged operation of a high-power pulse-periodic CO2 laser without replenishment of the gas mixture in a closed loop. Certain characteristic features concerning the use of hopcalite are described.

Gas Control System for HEAO-B

Science.gov (United States)

Taylor, B.; Brissette, R.; Humphrey, A.; Morris, J.; Luger, J.; Swift, W.

1978-01-01

The HEAO-B Gas Control System consists of a high pressure gas storage supply together with distribution and regulation assemblies and their associated electronics for management of gas required for HEAO-B X-ray counter experiments. The Gas Control System replenishes a gas mixture (82 percent argon, 12.3 percent carbon dioxide, 5.7 percent xenon) in the counter volumes which is lost by: diffusion through controlled leakage plugs, diffusion through counter windows, and consumption resulting from periodic purges. The gas density in each counter volume is maintained constant to within 0.25 percent by comparison with a sealed reference volume. The system is fully redundant, capable of operating at atmospheric pressure as well as in a vacuum, contains interlocks which shut down gas flow in the event of either leakage or excessive pressure, and is able to shut down counter high voltage if counter pressure is abnormally low. The system is electronically controlled by ground command and self-sustaining in orbit for a period of at least one year.

Joint replenishment and credit policies under two levels of trade credit financing when demand and bad-debt loss depends upon credit period

Directory of Open Access Journals (Sweden)

Aggarawal K.K.

2016-01-01

Full Text Available In practice, a firm usually receives trade credit financing from its supplier on the purchase of inventory. Similarly, in order to meet competition and generate credit sales over and above cash sales, the firm also gives credit period to their customers. However, the decision of granting credit period may have a disintegrating effect on cash sales apart from generating new credit sales because some of the cash customers may switch to credit purchase. In addition, despite of the best credit granting policies and collection practices, the firm may incurs some amount of bad debt losses because a certain fraction of buyers will undoubtedly be unable to pay off their debt obligations and become bad debt loss to the firm. In this paper, using discounted cash flow (DCF approach, a mathematical model is developed to jointly determine optimal inventory and credit policies under two levels of trade credit financing when demand and bad-debt losses are dependent on credit period. The objective of the model is to maximize the present value of firm’s net profit per unit time by jointly optimizing the replenishment interval and date-terms credit period. Numerical examples and sensitivity analysis are presented to illustrate the effectiveness of the proposed model, and the results are discussed.

A replenishment policy for a perishable inventory system based on estimated aging and retrieval behavior

NARCIS (Netherlands)

Broekmeulen, R.A.C.M.; Donselaar, van K.H.

2007-01-01

So far the literature on inventory control for perishable products has mainly focused on (near-) optimal replenishment policies for a stylized environment, assuming no leadtime, no lot-sizing, stationary demand, a first in first out retrieval policy and/or product life time equal to two periods.

Insight into the risk of replenishing urban landscape ponds with reclaimed wastewater.

Science.gov (United States)

Chen, Rong; Ao, Dong; Ji, Jiayuan; Wang, Xiaochang C; Li, Yu-You; Huang, Yue; Xue, Tao; Guo, Hongbing; Wang, Nan; Zhang, Lu

2017-02-15

Increasing use of reclaimed wastewater (RW) for replenishing urban landscape ponds has aroused public concern about the water quality. Three ponds replenished with RW in three cities in China were chosen to investigate 22 indexes of water quality in five categories. This was achieved by comparing three pairs of ponds in the three different cities, where one pond in each pair was replenished with RW and the other with surface water (SW). The nutrients condition, heavy metal concentration and ecotoxicity did not differ significantly between RW- and SW-replenished ponds. By contrast, significant differences were observed in algal growth and pathogen risk. RW ponds presented a Cyanophyta-Chlorophyta-Bacillariophyta type with high algal diversity while SW ponds presented a Cyanophyta type with low diversity. Regrowth of bacterial pathogens and especially survival of viral pathogens in RW, was the main driver behind the higher risk for RW ponds compared with SW ones. The duration of RW replenishment was proved to have a marked impact on the algal growth and pathogen risk. With continued RW replenishment, non-dominant algal species subjected to decrease while dominant species were enhanced resulting in the biomass increasing but diversity declining, and the risk posed by viral pathogens might become greater. Copyright © 2016 Elsevier B.V. All rights reserved.

Model of the impact of parameters controlling replenishment in the bs (min-max) continuous review system on the actual inventory availibility

OpenAIRE

Stanisław Krzyżaniak

2015-01-01

Background: Due to random changes in demand, inventory management is still - despite the development of alternative goods flow management concepts - an important issue both in terms of costs of maintenance and replenishment as well as the level of service measured by inventory availability levels. There are a number of replenishment systems to be used in such conditions, but they are most often formed on the basis of two basic ones: a system based on the reorder point and based on periodic in...

PERIODIC REVIEW SYSTEM FOR INVENTORY REPLENISHMENT CONTROL FOR A TWO-ECHELON LOGISTICS NETWORK UNDER DEMAND UNCERTAINTY: A TWO-STAGE STOCHASTIC PROGRAMING APPROACH

Directory of Open Access Journals (Sweden)

P.S.A. Cunha

Full Text Available ABSTRACT Here, we propose a novel methodology for replenishment and control systems for inventories of two-echelon logistics networks using a two-stage stochastic programming, considering periodic review and uncertain demands. In addition, to achieve better customer services, we introduce a variable rationing rule to address quantities of the item in short. The devised models are reformulated into their deterministic equivalent, resulting in nonlinear mixed-integer programming models, which are then approximately linearized. To deal with the uncertain nature of the item demand levels, we apply a Monte Carlo simulation-based method to generate finite and discrete sets of scenarios. Moreover, the proposed approach does not require restricted assumptions to the behavior of the probabilistic phenomena, as does several existing methods in the literature. Numerical experiments with the proposed approach for randomly generated instances of the problem show results with errors around 1%.

2025 Aerospace Replenishment: The Insidious Force Multiplier

National Research Council Canada - National Science Library

Smith, Yoshio

1996-01-01

.... Even if this were possible, replenishment should be better exploited to mitigate the effect of supporting all or most operations from the United States a likely prospect in the not too distant future...

Coordinating supplier-retailer using multiple common replenishment epochs with retailers’ choices

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Juhwen Hwang

2013-06-01

Full Text Available Purpose: Provide a coordination strategy using multiple common replenishment epochs (MCRE for a single-supplier multi-retailer supply chain. Design/methodology/approach: The demand of a product occurs only with a group of heterogeneous and independent retailers with constant rates, whereas all their order requests are fulfilled by the supplier. The supplier decides a set of MCREs with general price and extra bonus to entice the retailers to join any one of the MCREs, or to let them remain with their original order time epochs. A retailer is willing to participate in a CRE as long as the retailer’s cost increase is within its tolerance. This paper provide a mixed integer programming to determine the MCRE strategies in order to minimize the total costs of the supplier. Findings: The results illustrate that MCRE model provided in the paper can generate a better replenishment coordination scheme than single CRE models. Practical implications: Replenishment coordination is one of the most important mechanisms to improve the efficiency in supply chains, e.g., chain convenience stores in the modern retail industry. Originality/value: This is a follow-up research on Joint Economic Lot Size (JELS models with a focus on multiple retailers with their replenishment coordination.

Self-Replenishing Vascularized Fouling-Release Surfaces

Energy Technology Data Exchange (ETDEWEB)

Howell, C; Vu, TL; Lin, JJ; Kolle, S; Juthani, N; Watson, E; Weaver, JC; Alvarenga, J; Aizenberg, J

2014-08-13

Inspired by the long-term effectiveness of living antifouling materials, we have developed a method for the self-replenishment of synthetic biofouling-release surfaces. These surfaces are created by either molding or directly embedding 3D vascular systems into polydimethylsiloxane (PDMS) and filling them with a silicone oil to generate a nontoxic oil-infused material. When replenished with silicone oil from an outside source, these materials are capable of self-lubrication and continuous renewal of the interfacial fouling-release layer. Under accelerated lubricant loss conditions, fully infused vascularized samples retained significantly more lubricant than equivalent nonvascularized controls. Tests of lubricant-infused PDMS in static cultures of the infectious bacteria Staphylococcus aureus and Escherichia coli as well as the green microalgae Botryococcus braunii, Chlamydomonas reinhardtii, Dunaliella sauna, and Nannochloropsis oculata showed a significant reduction in biofilm adhesion compared to PDMS and glass controls containing no lubricant. Further experiments on vascularized versus nonvascularized samples that had been subjected to accelerated lubricant evaporation conditions for up to 48 h showed significantly less biofilm adherence on the vascularized surfaces. These results demonstrate the ability of an embedded lubricant-filled vascular network to improve the longevity of fouling-release surfaces.

Explosive dome eruptions modulated by periodic gas-driven inflation

Science.gov (United States)

Johnson, Jeffrey B.; Lyons, John; Andrews, B. J.; Lees, J.M.

2014-01-01

Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~101 kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ascent feeds pyroclast-laden eruptions lasting several minutes and rising to ~1 km. VLPs are not observed during less rapid inflation episodes; instead, gas vents passively through the conduit producing no infrasound and no explosion. These observations intimate that steady gas exsolution and accumulation in shallow reservoirs may drive inflation cycles at open-vent silicic volcanoes.

On the role of trust types and levels on inventory replenishment decision

OpenAIRE

Darvish, M.; Kaboli, A.; Cheikhrouhou, N.; Glardon, R.

2014-01-01

Using a participatory simulation platform, this paper investigates the inventory replenishment decisions made under different trust categories. Depending on the type of trust (trust in supplier versus trust in customer) and level of trust (high versus low), each decision is categorized and analyzed. We investigate how the inventory manager`s ordering behavior varies regarding their type and level of trust. This study provides evidence for the role of trust in inventory replenishment decision....

Modeling Replenishment of Ultrathin Liquid Perfluoro polyether Z Films on Solid Surfaces Using Monte Carlo Simulation

International Nuclear Information System (INIS)

Mayeed, M.S.; Kato, T.

2014-01-01

Applying the reptation algorithm to a simplified perfluoro polyether Z off-lattice polymer model an NVT Monte Carlo simulation has been performed. Bulk condition has been simulated first to compare the average radius of gyration with the bulk experimental results. Then the model is tested for its ability to describe dynamics. After this, it is applied to observe the replenishment of nano scale ultrathin liquid films on solid flat carbon surfaces. The replenishment rate for trenches of different widths (8, 12, and 16 nms for several molecular weights) between two films of perfluoro polyether Z from the Monte Carlo simulation is compared to that obtained solving the diffusion equation using the experimental diffusion coefficients of Ma et al. (1999), with room condition in both cases. Replenishment per Monte Carlo cycle seems to be a constant multiple of replenishment per second at least up to 2 nm replenished film thickness of the trenches over the carbon surface. Considerable good agreement has been achieved here between the experimental results and the dynamics of molecules using reptation moves in the ultrathin liquid films on solid surfaces.

Partial podocyte replenishment in experimental FSGS derives from nonpodocyte sources.

Science.gov (United States)

Kaverina, Natalya V; Eng, Diana G; Schneider, Remington R S; Pippin, Jeffrey W; Shankland, Stuart J

2016-06-01

The current studies used genetic fate mapping to prove that adult podocytes can be partially replenished following depletion. Inducible NPHS2-rtTA/tetO-Cre/RS-ZsGreen-R reporter mice were generated to permanently label podocytes with the ZsGreen reporter. Experimental focal segmental glomerulosclerosis (FSGS) was induced with a cytotoxic podocyte antibody. On FSGS day 7, immunostaining for the podocyte markers p57, synaptopodin, and podocin were markedly decreased by 44%, and this was accompanied by a decrease in ZsGreen fluorescence. The nuclear stain DAPI was absent in segments of reduced ZsGreen and podocyte marker staining, which is consistent with podocyte depletion. Staining for p57, synaptopodin, podocin, and DAPI increased at FSGS day 28 and was augmented by the ACE inhibitor enalapril, which is consistent with a partial replenishment of podocytes. In contrast, ZsGreen fluorescence did not return and remained significantly low at day 28, indicating replenishment was from a nonpodocyte origin. Despite administration of bromodeoxyuridine (BrdU) thrice weekly throughout the course of disease, BrdU staining was not detected in podocytes, which is consistent with an absence of proliferation. Although ZsGreen reporting was reduced in the tuft at FSGS day 28, labeled podocytes were detected along the Bowman's capsule in a subset of glomeruli, which is consistent with migration from the tuft. Moreover, more than half of the migrated podocytes coexpressed the parietal epithelial cell (PEC) proteins claudin-1, SSeCKS, and PAX8. These results show that although podocytes can be partially replenished following abrupt depletion, a process augmented by ACE inhibition, the source or sources are nonpodocyte in origin and are independent of proliferation. Furthermore, a subset of podocytes migrate to the Bowman's capsule and begin to coexpress PEC markers. Copyright © 2016 the American Physiological Society.

MILP for the Inventory and Routing for Replenishment Problem in the Car Assembly Line.

Directory of Open Access Journals (Sweden)

Raul Pulido

2014-01-01

Full Text Available The inbound logistic for feeding the workstation inside the factory represents a critical issue in the car manufacturing industry. Nowadays, this issue is even more critical than in the past since more types of car are being produced in the assembly lines. Consequently, as workstations have to install many types of components, they also need to have an inventory of different types of the component in a compact space.The replenishment is a critical issue since a lack of inventory could cause line stoppage or reworking. On the other hand, an excess of inventory could increase the holding cost or even block the replenishment paths. The decision of the replenishment routes cannot be made without taking into consideration the inventory needed by each station during the production time which will depend on the production sequence. This problem deals with medium-sized instances and it is solved using online solvers. The contribution of this paper is a MILP for the replenishment and inventory of the components in a car assembly line.

Replenishing Humic Acids in Agricultural Soils

Directory of Open Access Journals (Sweden)

Michael Susic

2016-09-01

Full Text Available For many decades, it was commonly believed that humic acids were formed in soils by the microbial conversion of plant lignins. However, an experiment to test whether these humic acids were formed prior to plant matter reaching the soil was never reported until the late 1980s (and then only as a side issue, even though humic acids were first isolated and reported in 1786. This was a serious omission, and led to a poor understanding of how the humic acid content of soils could be maintained or increased for optimum fertility. In this study, commercial sugar cane mulch and kelp extracts were extracted with alkali and analyzed for humic acid content. Humic acids in the extracts were positively identified by fluorescence spectrophotometry, and this demonstrated that humic acids are formed in senescent plant and algal matter before they reach the soil, where they are then strongly bound to the soil and are also resistant to microbial metabolism. Humic acids are removed from soils by wind and water erosion, and by water leaching, which means that they must be regularly replenished. This study shows that soils can be replenished or fortified with humic acids simply by recycling plant and algal matter, or by adding outside sources of decomposed plant or algal matter such as composts, mulch, peat, and lignite coals.

Power Replenishment Patch for Spacecraft Health Monitoring Sensors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Metis Design Corporation (MDC) proposes the development of a strain-based power replenishment technology to harvest energy for recharging remote sensors. MDC has...

Replenishing data descriptors in a DMA injection FIFO buffer

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Cernohous, Bob R [Rochester, MN; Heidelberger, Philip [Cortlandt Manor, NY; Kumar, Sameer [White Plains, NY; Parker, Jeffrey J [Rochester, MN

2011-10-11

Methods, apparatus, and products are disclosed for replenishing data descriptors in a Direct Memory Access (`DMA`) injection first-in-first-out (`FIFO`) buffer that include: determining, by a messaging module on an origin compute node, whether a number of data descriptors in a DMA injection FIFO buffer exceeds a predetermined threshold, each data descriptor specifying an application message for transmission to a target compute node; queuing, by the messaging module, a plurality of new data descriptors in a pending descriptor queue if the number of the data descriptors in the DMA injection FIFO buffer exceeds the predetermined threshold; establishing, by the messaging module, interrupt criteria that specify when to replenish the injection FIFO buffer with the plurality of new data descriptors in the pending descriptor queue; and injecting, by the messaging module, the plurality of new data descriptors into the injection FIFO buffer in dependence upon the interrupt criteria.

Optimal dynamic pricing and replenishment policy for perishable items with inventory-level-dependent demand

Science.gov (United States)

Lu, Lihao; Zhang, Jianxiong; Tang, Wansheng

2016-04-01

An inventory system for perishable items with limited replenishment capacity is introduced in this paper. The demand rate depends on the stock quantity displayed in the store as well as the sales price. With the goal to realise profit maximisation, an optimisation problem is addressed to seek for the optimal joint dynamic pricing and replenishment policy which is obtained by solving the optimisation problem with Pontryagin's maximum principle. A joint mixed policy, in which the sales price is a static decision variable and the replenishment rate remains to be a dynamic decision variable, is presented to compare with the joint dynamic policy. Numerical results demonstrate the advantages of the joint dynamic one, and further show the effects of different system parameters on the optimal joint dynamic policy and the maximal total profit.

Approximation algorithms for replenishment problems with fixed turnover times

NARCIS (Netherlands)

T. Bosman (Thomas); M. van Ee (Martijn); Y. Jiao (Yang); A. Marchetti Spaccamela (Alberto); R. Ravi; L. Stougie (Leen)

2018-01-01

textabstractWe introduce and study a class of optimization problems we coin replenishment problems with fixed turnover times: a very natural model that has received little attention in the literature. Nodes with capacity for storing a certain commodity are located at various places; at each node the

Decomposition of water into highly combustible hydroxyl gas used in ...

African Journals Online (AJOL)

The method proposed involves the decomposition of water into highly combustible hydroxyl gas via electrolysis, which is used in internal combustion engines of electrical generators for electricity generation. The by-product obtained from combustion of this gas is water vapour and oxygen to replenish the atmosphere.

The Multi-Location Transshipment Problem with Positive Replenishment Lead Times

NARCIS (Netherlands)

Y. Gong (Yeming); E. Yucesan

2006-01-01

textabstractTransshipments, monitored movements of material at the same echelon of a supply chain, represent an effective pooling mechanism. With a single exception, research on transshipments overlooks replenishment lead times. The only approach for two-location inventory systems with

Calculation of nonstationary gas-dynamic flows with periodic local supply of energy

International Nuclear Information System (INIS)

Mikhailova, N.V.; Myshetskaya, E.E.; Rakhimov, A.T.; Favorskii, A.P.

The paper considers the motion of a flow of gas with local supply of energy periodic in time. Solution of the problem in one-dimensional formulation in the approximation of an ideal nonviscous non-heat-conducting gas is carried out by numerical methods. The possibility of emergence of the flow into a periodic regime is established and the rate of this process is calculated. The character of the periodic structure is investigated in dependence on the frequency of the superimposition of perturbations and the Mach number in unperturbed flow of the gas

Predaceous ants, beach replenishment, and nest placement by sea turtles.

Science.gov (United States)

Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

2007-10-01

Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

Output synchronization control of ship replenishment operations: theory and experiments

NARCIS (Netherlands)

Kyrkjebø, E.; Pettersen, K.Y.; Wondergem, M.; Nijmeijer, H.

2007-01-01

A leader–follower synchronization output feedback control scheme is presented for the ship replenishment problem where only positions are measured. No mathematical model of the leader ship is required, and the control scheme relies on nonlinear observers to estimate velocity and acceleration of all

Operational Qualification (OQ) Of MINTEC-Sinagama After Cobalt-60 Sources Replenishment

International Nuclear Information System (INIS)

Ruzalina Baharin; Hasan Sham; Ahsanulkhaliqin Abdul Wahab

2014-01-01

Activity on cobalt-60 sources replenishment at MINTec-Sinagama had been held in May 2014 with total strength of gamma as 440,000 Ci. Therefore, operational qualification (OQ) needs to be done in order to ensure that Sinagama plant is operating well and deliver suitable doses to the customer's products. In this work, three dose mapping exercises were carried out to establish dose distributions and dose reproducibility of plant, which are corresponded to the density of irradiator container (tote) and absorbed dose at normal operation. Dosimeters used were ceric cerous produced by SSDL, Malaysian Nuclear Agency and placed on three planes that represent three-dimensional array. They were located at certain intervals throughout the tote. This paper describes the OQ process and a bit touch on replenishment activity. (author)

Stimulation of flower nectar replenishment by removal: A survey of eleven animal-pollinated plant species

Directory of Open Access Journals (Sweden)

Elaine Y Luo

2014-02-01

Full Text Available Understanding the interaction between reward-seeking flower feeding animals and plants requires consideration of the dynamic nature of nectar secretion. Studies on several plants suggest that nectar secretion may increase in response to its removal, but it is not clear whether the phenomenon is widespread. We determined whether 11 species of Colorado mountain wildflowers showed removal-enhanced nectar replenishment (RENR. We measured floral phenology, nectar volumes, rate of replenishment, and compared the cumulative nectar produced following five hourly removals with that accumulated after five hours. Nectar replenishment occurred rapidly, within minutes; statistically significant RENR was observed in 9 of our 11 study species, with the strongest effects in bee-pollinated species. We discuss the implications of RENR in plant species on the measurement of nectar, the adaptive advantage of RENR, and the energetic costs of RENR.

Analysis of image factors of x-ray films : study for the intelligent replenishment system of automatic film processor

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Tae; Yoon, Chong Hyun; Park, Kwang BO; Auh, Yong Ho; Lee, Hyoung Jin; In, Kyung Hwan; Kim, Keon Chung [Asan Medical Center, Ulsan Univ. College of Medicine, Ulsan (Korea, Republic of)

1998-06-01

We analyzed image factors to determine the characteristic factors that need for intelligent replenishment system of the auto film processor. We processed the serial 300 sheets of radiographic films of chest phantom without replenishment of developing and fixation replenisher. We took the digital data by using film digitizer which scanned the films and automatically summed up the pixel values of the films. We analyzed characteristic curves, average gradients and relative speeds of individual film using densitometer and step densitometry. We also evaluated the pH of developer, fixer, and washer fluid with digital pH meter. Fixer residual rate and washing effect were measured by densitometer using the reagent methods. There was no significant reduction of the digital density numbers of the serial films without replenishment of developer and fixer. The average gradients were gradually decreased by 0.02 and relative speeds were also gradually decreased by 6.96% relative to initial standard step-densitometric measurement. The pHs of developer and fixer were reflected the inactivation of each fluid. The fixer residual rates and washing effects after processing each 25 sheets of films were in the normal range. We suggest that the digital data are not reliable due to limitation of the hardware and software of the film digitizer. We conclude that average gradient and relative speed which mean the film's contrast and sensitivity respectively are reliable factors for determining the need for the replenishment of the auto film processor. We need more study of simpler equations and programming for more intelligent replenishment system of the auto film processor.

Application of Notched Long-Period Fiber Grating Based Sensor for CO2 Gas Sensing

Science.gov (United States)

Wu, Chao-Wei; Chiang, Chia-Chin

2016-01-01

An inductively coupled plasma etching process to fabricate notched long-period fiber gratings for CO2 gas sensing is proposed in this article. In the gas sensing test, the 15% mixed CO2 gas was used for characterization of CO2 adsorption by the amine-modified nanoporous silica foams of the notched long-period fiber grating sensor. The results shows the spectra were changed with the CO2 gas flow within 13 min. During the absorption process, the transmission of the resonant dip was decreased by 2.884 dB. Therefore, the proposed notched long-period fiber grating gas sensor shows good performance and is suitable as a gas sensor for monitoring the CO2 adsorption process.

On the risks from sediment and overlying water by replenishing urban landscape ponds with reclaimed wastewater.

Science.gov (United States)

Ao, Dong; Chen, Rong; Wang, Xiaochang C; Liu, Yanzheng; Dzakpasu, Mawuli; Zhang, Lu; Huang, Yue; Xue, Tao; Wang, Nan

2018-05-01

The extensive use of reclaimed wastewater (RW) as a source of urban landscape pond replenishment, stimulated by the lack of surface water (SW) resources, has raised public concern. Greater attention should be paid to pond sediments, which act as 'sinks' and 'sources' of contaminants to the overlying pond water. Three ponds replenished with RW (RW ponds) in three Chinese cities were chosen to investigate 22 indices of sediment quality in four categories: eutrophication, heavy metal, ecotoxicity and pathogens risk. RW ponds were compared with other ponds of similar characteristics in the same cities that were replenished with SW (SW ponds). Our results show a strong impact of RW to the eutrophication and pathogenic risks, which are represented by organic matter, water content, total nitrogen, total phosphorus and phosphorus fractions, and pathogens. In particular, total phosphorus concentrations in the RW pond sediments were, on average, 50% higher than those of SW ponds. Moreover, the content of phosphorus, extracted by bicarbonate/dithionite (normally represented by BD-P) and NaOH (NaOH-P), were 2.0- and 2.83-times higher in RW ponds, respectively. For pathogens, the concentrations of norovirus and rotavirus in RW pond sediments were, on average, 0.52 and 0.30- log times those of SW ponds. The duration of RW replenishment was proved to have a marked impact on the eutrophication and pathogens risks from sediments. The continued use of RW for replenishment increases the eutrophication risk, and the pathogens risk, especially by viral pathogens, becomes greater. Copyright © 2018 Elsevier Ltd. All rights reserved.

A simulation based approach to optimize inventory replenishment with RAND algorithm: An extended study of corrected demand using Holt's method for textile industry

Science.gov (United States)

Morshed, Mohammad Sarwar; Kamal, Mostafa Mashnoon; Khan, Somaiya Islam

2016-07-01

Inventory has been a major concern in supply chain and numerous researches have been done lately on inventory control which brought forth a number of methods that efficiently manage inventory and related overheads by reducing cost of replenishment. This research is aimed towards providing a better replenishment policy in case of multi-product, single supplier situations for chemical raw materials of textile industries in Bangladesh. It is assumed that industries currently pursue individual replenishment system. The purpose is to find out the optimum ideal cycle time and individual replenishment cycle time of each product for replenishment that will cause lowest annual holding and ordering cost, and also find the optimum ordering quantity. In this paper indirect grouping strategy has been used. It is suggested that indirect grouping Strategy outperforms direct grouping strategy when major cost is high. An algorithm by Kaspi and Rosenblatt (1991) called RAND is exercised for its simplicity and ease of application. RAND provides an ideal cycle time (T) for replenishment and integer multiplier (ki) for individual items. Thus the replenishment cycle time for each product is found as T×ki. Firstly, based on data, a comparison between currently prevailing (individual) process and RAND is provided that uses the actual demands which presents 49% improvement in total cost of replenishment. Secondly, discrepancies in demand is corrected by using Holt's method. However, demands can only be forecasted one or two months into the future because of the demand pattern of the industry under consideration. Evidently, application of RAND with corrected demand display even greater improvement. The results of this study demonstrates that cost of replenishment can be significantly reduced by applying RAND algorithm and exponential smoothing models.

Two-Phase Gas-Liquid Flow Structure Characteristics under Periodic Cross Forces Action

Directory of Open Access Journals (Sweden)

V. V. Perevezentsev

2015-01-01

Full Text Available The article presents a study of two-phase gas-liquid flow under the action of periodic cross forces. The work objective is to obtain experimental data for further analysis and have structure characteristics of the two-phase flow movement. For research, to obtain data without disturbing effect on the flow were used optic PIV (Particle Image Visualization methods because of their noninvasiveness. The cross forces influence was provided by an experimental stand design to change the angular amplitudes and the periods of channel movement cycle with two-phase flow. In the range of volume gas rates was shown a water flow rate versus the inclination angle of immovable riser section and the characteristic angular amplitudes and periods of riser section inclination cycle under periodic cross forces. Data on distribution of average water velocity in twophase flow in abovementioned cases were also obtained. These data allowed us to draw a conclusion that a velocity distribution depends on the angular amplitude and on the period of the riser section roll cycle. This article belongs to publications, which study two-phase flows with no disturbing effect on them. Obtained data give an insight into understanding a pattern of twophase gas-liquid flow under the action of periodic cross forces and can be used to verify the mathematical models of the CFD thermo-hydraulic codes. In the future, the work development expects taking measurements with more frequent interval in the ranges of angular amplitudes and periods of the channel movement cycle and create a mathematical model to show the action of periodic cross forces on two-phase gas-liquid flow.

Hydromagnetic Rayleigh endash Taylor instability in high-velocity gas-puff implosions

International Nuclear Information System (INIS)

Roderick, N.F.; Peterkin, R.E. Jr.; Hussey, T.W.; Spielman, R.B.; Douglas, M.R.; Deeney, C.

1998-01-01

Experiments using the Saturn pulsed power generator have produced high-velocity z-pinch plasma implosions with velocities over 100 cm/μs using both annular and uniform-fill gas injection initial conditions. Both types of implosion show evidence of the hydromagnetic Rayleigh endash Taylor instability with the uniform-fill plasmas producing a more spatially uniform pinch. Two-dimensional magnetohydrodynamic simulations including unsteady flow of gas from a nozzle into the diode region have been used to investigate these implosions. The instability develops from the nonuniform gas flow field that forms as the gas expands from the injection nozzle. Instability growth is limited to the narrow unstable region of the current sheath. For the annular puff the unstable region breaks through the inner edge of the annulus increasing nonlinear growth as mass ejected from the bubble regions is not replenished by accretion. This higher growth leads to bubble thinning and disruption producing greater nonuniformity at pinch for the annular puff. The uniform puff provides gas to replenish bubble mass loss until just before pinch resulting in less bubble thinning and a more uniform pinch. copyright 1998 American Institute of Physics

A hybrid replenishment model, the best fit in fast growing industries

NARCIS (Netherlands)

Hartevelt, R.

2011-01-01

During the design supply chain control processes, balancing cost versus service plays an important role. To select the most suitable replenishment strategy is the main enabler in reaching the goal of finding the optimal balance. In this article a framework is developed which will help to select the

Optimal pricing and replenishment policies for instantaneous deteriorating items with backlogging and trade credit under inflation

Science.gov (United States)

Sundara Rajan, R.; Uthayakumar, R.

2017-12-01

In this paper we develop an economic order quantity model to investigate the optimal replenishment policies for instantaneous deteriorating items under inflation and trade credit. Demand rate is a linear function of selling price and decreases negative exponentially with time over a finite planning horizon. Shortages are allowed and partially backlogged. Under these conditions, we model the retailer's inventory system as a profit maximization problem to determine the optimal selling price, optimal order quantity and optimal replenishment time. An easy-to-use algorithm is developed to determine the optimal replenishment policies for the retailer. We also provide optimal present value of profit when shortages are completely backlogged as a special case. Numerical examples are presented to illustrate the algorithm provided to obtain optimal profit. And we also obtain managerial implications from numerical examples to substantiate our model. The results show that there is an improvement in total profit from complete backlogging rather than the items being partially backlogged.

Oil fuel delivery optimization for multi product and multi depot: the case of petrol station replenishment problem (PSRP)

Science.gov (United States)

Surjandari, Isti; Rachman, Amar; Dianawati, Fauzia; Wibowo, R. Pramono

2011-10-01

With the Oil and Gas Law No. 22 of 2001, national and foreign private enterprises can invest in all sectors of Oil and Gas in Indonesia. In anticipation of this free competition, Pertamina, as a state-owned enterprises, which previously had monopolized the oil and gas business activities in Indonesia, should be able to improve services as well as the efficiency in order to compete in the free market, especially in terms of cost efficiency of fuel distribution to gas station (SPBU). To optimize the distribution activity, it is necessary to design a scheduling system and its fuel delivery routes daily to every SPBU. The determination of routes and scheduling delivery of fuel to the SPBU can be modeled as a Petrol Station Replenishment Problem (PSRP) with the multi-depot, multi-product, time windows and split deliveries, which in this study will be completed by the Tabu Search algorithm (TS). This study was conducted in the area of Bandung, the capital of West Java province, which is a big city and the neighboring city of Jakarta, the capital city of Indonesia. By using the fuel delivery data for one day, the results showed a decrease of 16.38% of the distance of the route compared to the current conditions, which impacted on the reduction of distribution costs and decrease the number of total trips by 5.22% and 3.83%.

Oils; gas

Energy Technology Data Exchange (ETDEWEB)

Day, D T

1922-09-18

Oils and gas are obtained from shale or oil-bearing sand by immersing the shale in and passing it through a bath of liquid oil, cracking the oil-soaked shale, and condensing the vapor and using the condensate to replenish the bath, preferably by passing the gases and vapors direct into the oil-bath container. Shale is fed continuously from a hopper to a bath of oil in an inclined chamber, is carried to the outlet by a conveyer, and through cracking tubes to an outlet pipe by conveyers. The gases and vapors escape by the pipe, a part condensing in the chamber and a run-back pipe and replenishing the bath, and the remainder passing through a condensing tower and condenser connected to reservoirs; the gas is further passed through a scrubber and a pipe to the burner of the retort. The oil condensed in the chamber overflows to the reservoir through a pipe provided with an open pipe to prevent siphoning. The conveyers and a valve on the pipe are operated by gearing. The operation may be conducted at reduced, normal, or increased pressure, e.g., 70 lbs. The temperature of the retort should be about 900 to 1400/sup 0/F, that of the inside of the tubes about 550 to 700/sup 0/F, and that of the chamber about 300/sup 0/F. The chamber and pipe may be insulated or artificially cooled.

Rapidly Dissolving Microneedle Patches for Transdermal Iron Replenishment Therapy.

Science.gov (United States)

Maurya, Abhijeet; Nanjappa, Shivakumar H; Honnavar, Swati; Salwa, M; Murthy, S Narasimha

2018-02-17

The prevalence of iron deficiency anemia (IDA) is predominant in women and children especially in developing countries. The disorder affects cognitive functions and physical activity. Although oral iron supplementation and parenteral therapy remains the preferred choice of treatment, gastric side effects and risk of iron overload decreases adherence to therapy. Transdermal route is an established approach, which circumvents the side effects associated with conventional therapy. In this project, an attempt was made to investigate the use of rapidly dissolving microneedles loaded with ferric pyrophosphate (FPP) as a potential therapeutic approach for management of IDA. Microneedle array patches were made using the micromolding technique and tested in vitro using rat skin to check the duration required for dissolution/disappearance of needles. The ability of FPP-loaded microneedles to replenish iron was investigated in anemic rats. Rats were fed iron-deficient diet for 5 weeks to induce IDA following which microneedle treatment was initiated. Recovery of rats from anemic state was monitored by measuring hematological and biochemical parameters. Results from in vivo study displayed significant improvements in hemoglobin and serum iron levels after 2-week treatment with FPP-loaded microneedles. The study effectively demonstrated the potential of microneedle-mediated iron replenishment for treatment of IDA. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The optimal replenishment policy for time-varying stochastic demand under vendor managed inventory

DEFF Research Database (Denmark)

Govindan, Kannan

2015-01-01

A Vendor Managed Inventory (VMI) partnership places the responsibility on the vendor (rather than on buyers) to schedule purchase orders for inventory replenishment in the supply chain system. In this research, the supply chain network considers the Silver-Meal heuristic with an augmentation...... quantity replenishment policy between both traditional and VMI systems. We consider time-varying stochastic demand in two-echelon (one vendor, multiple retailers) supply chains. This paper seeks to find the supply chain that minimizes system cost through comparing performance between traditional and VMI...... systems. A mathematical model is developed, and total supply chain cost is used as the measure of comparison. The models are applied in both traditional and VMI supply chains based on pharmaceutical industry data, and we focus on total cost difference compared through the use of Adjusted Silver-Meal (ASM...

Model of the impact of parameters controlling replenishment in the bs (min-max continuous review system on the actual inventory availibility

Directory of Open Access Journals (Sweden)

Stanisław Krzyżaniak

2015-09-01

Full Text Available Background: Due to random changes in demand, inventory management is still - despite the development of alternative goods flow management concepts - an important issue both in terms of costs of maintenance and replenishment as well as the level of service measured by inventory availability levels. There are a number of replenishment systems to be used in such conditions, but they are most often formed on the basis of two basic ones: a system based on the reorder point and based on periodic inspection.  This paper refers to the former system, the BS system (min-max, in which an order is placed after reaching inventory level B (information level, reorder point for a quantity allowing to reach level S. This system is very often used in business practice. Observations conducted under realistic conditions indicate the need to improve the classical models describing the system.  This results, among other things, from the fact that the actual level of available inventory at the start of the replenishment cycle may be significantly lower than level B, resulting in lower than expected levels of customer service. Taking account of this phenomenon through model determination of the cumulative distribution function for the observed difference makes it possible to select the correct parameters to control the replenishment system in question and - therefore - to achieve the expected economic effects. Methods: The object of the study is to create a mathematical model allowing the determination of the required inventory level B taking into account the difference D between this level and the actual level of inventory at the start of the replenishment cycle.  To determine the effect of various factors such as demand distribution parameters in the adopted unit of time and the difference between level S (max and B (min, a dedicated tool (simulator in EXCEL spreadsheet for determining the distribution of frequency of value D has been developed.  Then a

Periodic reviews of structural integrity of gas-cooled reactors

International Nuclear Information System (INIS)

Banks, P.J.; Stokoe, T.Y.; Thomas, D.L.

1995-01-01

Nuclear Electric operates 12 gas-cooled reactor power stations which have been in service for between 5 and 30 years. Periodically, comprehensive reviews of the safety cases are carried out for each station. The approach followed in these reviews in respect of structural integrity is outlined with the use of illustrative examples. (author)

Preliminary Experimental Results on the Technique of Artificial River Replenishment to Mitigate Sediment Loss Downstream Dams

Science.gov (United States)

Franca, M. J.; Battisacco, E.; Schleiss, A. J.

2014-12-01

The transport of sediments by water throughout the river basins, from the steep slopes of the upstream regions to the sea level, is recognizable important to keep the natural conditions of rivers with a role on their ecology processes. Over the last decades, a reduction on the supply of sand and gravel has been observed downstream dams existing in several alpine rivers. Many studies highlight that the presence of a dam strongly modifies the river behavior in the downstream reach, in terms of morphology and hydrodynamics, with consequences on local ecology. Sediment deficit, bed armoring, river incision and bank instability are the main effects which affect negatively the aquatic habitats and the water quality. One of the proposed techniques to solve the problem of sediment deficit downstream dams, already adopted in few Japanese and German rivers although on an unsatisfactory fashion, is the artificial replenishment of these. Generally, it was verified that the erosion of the replenishments was not satisfactory and the transport rate was not enough to move the sediments to sufficient downstream distances. In order to improve and to provide an engineering answer to make this technique more applicable, a series of laboratory tests are ran as preparatory study to understand the hydrodynamics of the river flow when the replenishment technique is applied. Erodible volumes, with different lengths and submergence conditions, reproducing sediment replenishments volumes, are positioned along a channel bank. Different geometrical combinations of erodible sediment volumes are tested as well on the experimental flume. The first results of the experimental research, concerning erosion time evolution, the influence of discharge and the distance travelled by the eroded sediments, will be presented and discussed.

The effect of replenishment policies on the bullwhip effect : a transfer function approach

NARCIS (Netherlands)

Jaksic, M.; Rusjan, B.

2008-01-01

An important phenomenon in supply chain management, known as the bullwhip effect, suggests that demand variability increases as one moves up a supply chain. This paper examines the influence of different replenishment policies on the occurrence of the bullwhip effect. The paper demonstrates that

The Optimal Replenishment Policy under Trade Credit Financing with Ramp Type Demand and Demand Dependent Production Rate

Directory of Open Access Journals (Sweden)

Juanjuan Qin

2014-01-01

Full Text Available This paper investigates the optimal replenishment policy for the retailer with the ramp type demand and demand dependent production rate involving the trade credit financing, which is not reported in the literatures. First, the two inventory models are developed under the above situation. Second, the algorithms are given to optimize the replenishment cycle time and the order quantity for the retailer. Finally, the numerical examples are carried out to illustrate the optimal solutions and the sensitivity analysis is performed. The results show that if the value of production rate is small, the retailer will lower the frequency of putting the orders to cut down the order cost; if the production rate is high, the demand dependent production rate has no effect on the optimal decisions. When the trade credit is less than the growth stage time, the retailer will shorten the replenishment cycle; when it is larger than the breakpoint of the demand, within the maturity stage of the products, the trade credit has no effect on the optimal order cycle and the optimal order quantity.

Determination of the replenishment mechanism in the Los naranjos zone, Mexico, by the use of environmental isotopic techniques

International Nuclear Information System (INIS)

Payne, B.R.; Sainz O, I.

1977-01-01

The aquifers of the Los Naranjos Zone in the State of Veracruz have two principal sources of replenishment: the infiltration of the waters of the Rio Blanco along its channel. Granted that the eventual control of the waters of the Rio Blanco is capable of seriously affecting the exploitation of subterranean waters which is being implanted, it becomes necessary to learn its relative importance as a source of replenishment. As conventional techniques would not give a quick and sure answer to this matter, resort was had to isotopic techniques to solve the problem. In the rivers 27 samples of surface water were taken and 28 samples of subterranean water in wells, which were analyzed by I.A.E.A. with headquarters in Vienna. Interpretation of the data indicated, without room for doubt, that infiltrated rainwater represents 67% of the replenishment in the neighborhood of the Rio Blanco, 85% in the area's center, and 100% in the zones distant from the Rio Blanco. (author)

Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

Science.gov (United States)

Jennings, Donald E.; Nixon, C. A.; Romani, P. N.; Bjoraker, G. L.; Sada, P. V.; Lunsford, A. W.; Boyle, R. J.; Hesman, B. E.; McCabe, G. H.

2009-01-01

As the .main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS(exp 1) and from the ground and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes.

The Economics of Groundwater Replenishment for Reliable Urban Water Supply

Directory of Open Access Journals (Sweden)

Lei Gao

2014-06-01

Full Text Available This paper explores the potential economic benefits of water banking in aquifers to meet drought and emergency supplies for cities where the population is growing and changing climate has reduced the availability of water. A simplified case study based on the city of Perth, Australia was used to estimate the savings that could be achieved by water banking. Scenarios for investment in seawater desalination plants and groundwater replenishment were considered over a 20 year period of growing demand, using a Monte Carlo analysis that embedded the Markov model. An optimisation algorithm identified the minimum cost solutions that met specified criteria for supply reliability. The impact of depreciation of recharge credits was explored. The results revealed savings of more than A$1B (~US$1B or 37% to 33% of supply augmentation costs by including water banking in aquifers for 95% and 99.5% reliability of supply respectively. When the hypothetically assumed recharge credit depreciation rate was increased from 1% p.a. to 10% p.a. savings were still 33% to 31% for the same reliabilities. These preliminary results show that water banking in aquifers has potential to offer a highly attractive solution for efficiently increasing the security of urban water supplies where aquifers are suitable.

The role of the geothermal gradient in the emplacement and replenishment of ground ice on Mars

Science.gov (United States)

Clifford, Stephen M.

1993-01-01

Knowledge of the mechanisms by which ground ice is emplaced, removed, and potentially replenished, are critical to understanding the climatic and hydrologic behavior of water on Mars, as well as the morphologic evolution of its surface. Because of the strong temperature dependence of the saturated vapor pressure of H2O, the atmospheric emplacement or replenishment of ground ice is prohibited below the depth at which crustal temperatures begin to monotonically increase due to geothermal heating. In contrast, the emplacement and replenishment of ground ice from reservoirs of H2O residing deep within the crust can occur by at least three different thermally-driven processes, involving all three phases of water. In this regard, Clifford has discussed how the presence of a geothermal gradient as small as 15 K/km can give rise to a corresponding vapor pressure gradient sufficient to drive the vertical transport of 1 km of water from a reservoir of ground water at depth to the base of the cryosphere every 10(exp 6) - 10(exp 7) years. This abstract expands on this earlier treatment by considering the influence of thermal gradients on the transport of H2O at temperatures below the freezing point.

Periodical gas flow around a well in porous media

International Nuclear Information System (INIS)

Shnaid, I.; Olek, S.

1996-01-01

Analytical solutions of the linearized governing equation are presented for periodic gas flow around a well in porous media. Two cases are considered: a fully penetrating well and a partially penetrating well. For the first case, a closed form solution is obtained, whereas for the second case the solution is in the form of eigenfunctions expansions. The results have practical application in compressed air energy storage. (authors)

75 FR 62345 - Minimum Balance Requirement and Automatic Replenishment Option for Deposit Account Holders

Science.gov (United States)

2010-10-08

... may establish a deposit account, make advance deposits into that account, and charge copyright fees... for copyright registration paid for by deposit account debits be submitted using the electronic... assesses service charges for deposit account overdrafts ($165) and dishonored deposit account replenishment...

Limited contemporary gene flow and high self-replenishment drives peripheral isolation in an endemic coral reef fish.

Science.gov (United States)

van der Meer, Martin H; Horne, John B; Gardner, Michael G; Hobbs, Jean-Paul A; Pratchett, Morgan; van Herwerden, Lynne

2013-06-01

Extensive ongoing degradation of coral reef habitats worldwide has lead to declines in abundance of coral reef fishes and local extinction of some species. Those most vulnerable are ecological specialists and endemic species. Determining connectivity between locations is vital to understanding recovery and long-term persistence of these species following local extinction. This study explored population connectivity in the ecologically-specialized endemic three-striped butterflyfish (Chaetodon tricinctus) using mt and msatDNA (nuclear microsatellites) to distinguish evolutionary versus contemporary gene flow, estimate self-replenishment and measure genetic diversity among locations at the remote Australian offshore coral reefs of Middleton Reef (MR), Elizabeth Reef (ER), Lord Howe Island (LHI), and Norfolk Island (NI). Mt and msatDNA suggested genetic differentiation of the most peripheral location (NI) from the remaining three locations (MR, ER, LHI). Despite high levels of mtDNA gene flow, there is limited msatDNA gene flow with evidence of high levels of self-replenishment (≥76%) at all four locations. Taken together, this suggests prolonged population recovery times following population declines. The peripheral population (NI) is most vulnerable to local extinction due to its relative isolation, extreme levels of self-replenishment (95%), and low contemporary abundance.

THE GAS CONSUMPTION HISTORY TO REDSHIFT 4

International Nuclear Information System (INIS)

Bauermeister, Amber; Blitz, Leo; Ma, Chung-Pei

2010-01-01

Using the observations of the star formation rate (SFR) and H I densities to z ∼ 4, with measurements of the molecular gas depletion rate (MGDR) and local density of H 2 at z = 0, we derive the history of the gas consumption by star formation to z ∼ 4. We find that closed-box models in which H 2 is not replenished by H I require improbably large increases in ρ(H 2 ) and a decrease in the MGDR with lookback time that is inconsistent with observations. Allowing the H 2 used in star formation to be replenished by H I does not alleviate the problem because observations show that there is very little evolution of ρ H I (z) from z = 0 to z = 4. We show that to be consistent with observational constraints, star formation on cosmic timescales must be fueled by intergalactic ionized gas, which may come from either accretion of gas through cold (but ionized) flows, or from ionized gas associated with accretion of dark matter halos. We constrain the rate at which the extragalactic ionized gas must be converted into H I and ultimately into H 2 . The ionized gas inflow rate roughly traces the SFR density: about 1-2 x 10 8 M sun Gyr -1 Mpc -3 from z ≅ 1-4, decreasing by about an order of magnitude from z = 1 to z = 0 with details depending largely on MGDR(t). All models considered require the volume-averaged density of ρ H 2 to increase by a factor of 1.5-10 to z ∼ 1.5 over the currently measured value. Because the molecular gas must reside in galaxies, it implies that galaxies at high-z must, on average, be more molecule rich than they are at the present epoch, which is consistent with observations. These quantitative results, derived solely from observations, agree well with cosmological simulations.

HTGR gas-turbine program. Semiannual progress report for period ending March 31, 1980

International Nuclear Information System (INIS)

1982-01-01

This report describes the conceptual design and analysis performed by General Atomic Company and its subcontractors for the US Department of Energy on the direct cycle gas turbine high-temperature gas-cooled reactor. The primary accomplishments for this period were cost reduction studies, turbomachinery failure analysis, and alternate plant concept evaluation

The World gas model. A multi-period mixed complementarity model for the global natural gas market

International Nuclear Information System (INIS)

Egging, Ruud; Holz, Franziska; Gabriel, Steven A.

2010-01-01

We provide the description, mathematical formulation and illustrative results of the World Gas Model, a multi-period complementarity model for the global natural gas market with explicit consideration of market power in the upstream market. Market players include producers, traders, pipeline and storage operators, LNG (liquefied natural gas) liquefiers and regasifiers as well as marketers. The model data set contains more than 80 countries and regions and covers 98% of world wide natural gas production and consumption. We also include a detailed representation of cross-border natural gas pipelines and constraints imposed by long-term contracts in the LNG market. The model is calibrated to match production and consumption projections from the PRIMES [EC. European energy and transport: trends to 2030-update 2007. Brussels: European Commission; 2008] and POLES models [EC. World energy technology outlook - 2050 (WETO-H2). Brussels: European Commission; 2006] up to 2030. The results of our numerical simulations illustrate how the supply shares of pipeline and LNG in various regions in the world develop very differently over time. LNG will continue to play a major role in the Asian market, also for new importers like China and India. Europe will expand its pipeline import capacities benefiting from its relative proximity to major gas suppliers. (author)

Multi-Period Natural Gas Market Modeling. Applications, Stochastic Extensions and Solution Approaches

International Nuclear Information System (INIS)

Egging, R.G.

2010-11-01

This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in

A theoretical study of stability and vacancy replenishing of MoO{sub 3}(0 1 0) surfaces in oxygen atmosphere

Energy Technology Data Exchange (ETDEWEB)

Lei, Yan-Hua; Chen, Zhao-Xu, E-mail: zxchen@nju.edu.cn

2016-01-15

Graphical abstract: - Highlights: • Under normal experimental conditions perfect surface of MoO{sub 3}(0 1 0) is favorable. • Line defects along asymmetric oxygen direction in lean oxygen condition are favored. • Vacancy replenishing occurs on vacancies formed by terminal and asymmetrical oxygen. - Abstract: Oxygen vacancies on transition metal oxide surfaces are catalytically very important. The stability, shape and replenishing process of the vacancies are critical to understanding reactions happening on the surfaces. In this paper we investigate the stability of various defective MoO{sub 3}(0 1 0) surfaces and examine the influence of environmental oxygen on the stability as well as the active sites for the replenishing process. Our calculations reveal that the line oxygen defect along a (asymmetric oxygen) direction is thermodynamically most favorable at higher defect concentration whereas point defect surfaces are unfavorable. Under normal experimental conditions the perfect surface dominates the MoO{sub 3}(0 1 0). We show that for stoichiometric surfaces of any oxides (A{sub x}O{sub y}) the formation energy per vacancy controls the favorable defect shape (line or point defects). Calculations indicate that O{sub 2} can dissociate readily on the surfaces that double vacancies share one Mo atom. The replenishing process of the oxygen vacancies through O{sub 2} dissociation most likely occurs on the double-vacancy containing one terminal and one asymmetrical oxygen vacancies.

Connectivity of a large embayment and coastal fishery: spawning aggregations in one bay source local and broad-scale fishery replenishment.

Science.gov (United States)

Hamer, P A; Acevedo, S; Jenkins, G P; Newman, A

2011-04-01

Ichthyoplankton sampling and otolith chemistry were used to determine the importance of transient spawning aggregations of snapper Chrysophrys auratus (Sparidae) in a large embayment, Port Phillip Bay (PPB), Australia, as a source of local and broad-scale fishery replenishment. Ichthyoplankton sampling across five spawning seasons within PPB, across the narrow entrance to the bay and in adjacent coastal waters, indicated that although spawning may occur in coastal waters, the spawning aggregations within the bay were the primary source of larval recruitment to the bay. Otolith chemical signatures previously characterized for 0+ year C. auratus of two cohorts (2000 and 2001) were used as the baseline signatures to quantify the contribution that fish derived from reproduction in PPB make to fishery replenishment. Sampling of these cohorts over a 5 year period at various widely dispersed fishery regions, combined with maximum likelihood analyses of the chemistry of the 0+ year otolith portions of these older fish, indicated that C. auratus of 1 to 3+ years of age displayed both local residency and broad-scale emigration from PPB to populate coastal waters and an adjacent bay (Western Port). While the PPB fishery was consistently dominated (>70%) by locally derived fish irrespective of cohort or age, the contribution of fish that had originated from PPB to distant populations increased with age. At 4 to 5+ years of age, when C. auratus mature and fully recruit to the fishery, populations of both cohorts across the entire central and western Victorian fishery, including two major embayments and c. 800 km of coastal waters, were dominated (>70%) by fish that had originated from the spawning aggregations and nursery habitat within PPB. Dependence of this broadly dispersed fishery on replenishment from heavily targeted spawning aggregations within one embayment has significant implications for management and monitoring programmes. © 2011 The Authors. Journal of Fish

Six-month low level chlorine dioxide gas inhalation toxicity study with two-week recovery period in rats

Directory of Open Access Journals (Sweden)

Akamatsu Akinori

2012-02-01

Full Text Available Abstract Background Chlorine dioxide (CD gas has a potent antimicrobial activity at extremely low concentration and may serve as a new tool for infection control occupationally as well as publicly. However, it remains unknown whether the chronic exposure of CD gas concentration effective against microbes is safe. Therefore, long-term, low concentration CD gas inhalation toxicity was studied in rats as a six-month continuous whole-body exposure followed by a two-week recovery period, so as to prove that the CD gas exposed up to 0.1 ppm (volume ratio is judged as safe on the basis of a battery of toxicological examinations. Methods CD gas at 0.05 ppm or 0.1 ppm for 24 hours/day and 7 days/week was exposed to rats for 6 months under an unrestrained condition with free access to chow and water in a chamber so as to simulate the ordinary lifestyle in human. The control animals were exposed to air only. During the study period, the body weight as well as the food and water consumptions were recorded. After the 6-month exposure and the 2-week recovery period, animals were sacrificed and a battery of toxicological examinations, including biochemistry, hematology, necropsy, organ weights and histopathology, were performed. Results Well regulated levels of CD gas were exposed throughout the chamber over the entire study period. No CD gas-related toxicity sign was observed during the whole study period. No significant difference was observed in body weight gain, food and water consumptions, and relative organ weight. In biochemistry and hematology examinations, changes did not appear to be related to CD gas toxicity. In necropsy and histopathology, no CD gas-related toxicity was observed even in expected target respiratory organs. Conclusions CD gas up to 0.1 ppm, exceeding the level effective against microbes, exposed to whole body in rats continuously for six months was not toxic, under a condition simulating the conventional lifestyle in human.

Multi-period natural gas market modeling Applications, stochastic extensions and solution approaches

Science.gov (United States)

Egging, Rudolf Gerardus

This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. 1 The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in

Locating replenishment stations for electric vehicles: Application to Danish traffic data

DEFF Research Database (Denmark)

Wen, Min; Laporte, Gilbert; Madsen, Oli B.G.

2012-01-01

for electric vehicles on a traffic network with flow-based demand. The objective is to optimize the network performance, for example to maximize the flow covered by a prefixed number of stations, or to minimize the number of stations needed to cover traffic flows. Two mixed integer linear programming......Environment-friendly electric vehicles have gained substantial attention in governments, industry and universities. The deployment of a network of recharging stations is essential given their limited travel range. This paper considers the problem of locating electronic replenishment stations...

Contingency factors in the configuration of information systems for continuous replenishment: a case study in Indonesia

NARCIS (Netherlands)

Nasution, R.A.; Nasution, R.A.; Stegwee, R.A.; de Bruijn, E.J.; Sadler, I.; Power, D.; Dapiran, G.P.

2002-01-01

Contingency theory provides a theoretical framework for analysing the implementation differences in the configuration of Information Systems for Continuous Replenishment in the retail sector. The configuration can be broken down into three arrangements: data processing and sharing arrangement,

The Q(s,S) control policy for the joint replenishment problem extended to the case of correlation among item-demands

DEFF Research Database (Denmark)

Larsen, Christian

2009-01-01

We develop an algorithm to compute an optimal Q(s,S) policy for the joint replenishment problem when demands follow a compound correlated Poisson process. It is a non-trivial generalization of the work by Nielsen and Larsen [2005. An analytical study of the Q(s,S) policy applied to the joint...... replenishment problem. European Journal of Operational Research 163, 721-732]. We make some numerical analyses on two-item problems where we compare the optimal Q(s,S) policy to the optimal uncoordinated (s,S) policies. The results indicate that the more negative the correlation the less advantageous...

Disposable penis and its replenishment in a simultaneous hermaphrodite

Science.gov (United States)

Sekizawa, Ayami; Seki, Satoko; Tokuzato, Masakazu; Shiga, Sakiko; Nakashima, Yasuhiro

2013-01-01

Although it is often thought that sexual selection is weaker in simultaneous hermaphrodites than in gonochorists, some simultaneous hermaphrodites exhibit bizarre mating behaviour. In the simultaneously hermaphroditic nudibranch Chromodoris reticulata, we found a peculiar mating behaviour, wherein the nudibranch autotomized its penis after each copulation and was able to copulate again within 24 h. To have sufficient length to be replenished for three copulations, the penis is compressed and spiralled internally. No other animal is known to repeatedly copulate using such ‘disposable penes’. Entangled sperm masses were observed on the outer surface of the autotomized penis, which is equipped with many backward-pointed spines. There is a possibility that the nudibranch removes sperm already stored in a mating partner's sperm storage organ(s). PMID:23407499

Micron-scale copper wires printed using femtosecond laser-induced forward transfer with automated donor replenishment

NARCIS (Netherlands)

Grant-Jacob, J.A.; Mills, B.; Feinaeugle, M.; Sones, C.L.; Oosterhuis, G.; Hoppenbrouwers, M.B.; Eason, R.W.

2013-01-01

We demonstrate the use of laser-induced forward transfer (LIFT) in combination with a novel donor replenishment scheme to print continuous copper wires. Wires of mm length, a few microns wide and submicron in height have been printed using a 800 nm, 1 kHz repetition rate, 150 fs pulsed laser. A 120

大规模定制环境下ATO供应链的混合补货策略%Mixed component replenishment policies for ATO supply chain under mass customization circumstance

Institute of Scientific and Technical Information of China (English)

但斌; 李宇雨; 黄波

2011-01-01

Since the Assetnble-to-Order (ATO) supply chain consisted of a manufacturer and multiple suppliers, a model of components production and replenishment in ATO supply chain under mass customization circumstance was constructed on the basis of ATO manufacturer replenished the components by Just-in-Time( JIT) replenishment method and the others by (Q, r) replenishment method. ATO manufacturer's mixed replenishment policy and component supplier's production policies were studied. The optimal algoritm of JIT replenishment mode and best replenishment policy was proposed. Theoretical and numerical analysis revealed that with higher purchasing cost, longer lead-time and bigger demand variance, the manufacturer should replenish the components by JIT replenishment method so that inventory cost could be reduced and the profit of supply chain was increased.%考虑按订单装配供应链由一个制造商和多个零部件供应商组成,按订单装配制造商对部分零部件采用准时制生产补货,其余零部件采用(Q,r)补货,建立了大规模定制环境下的按订单装配供应链零部件生产补货模型,研究了按订单装配制造商的混合补货策略和零部件供应商的生产策略,给出了制造商采用准时制生产补货方式的条件和供应链最优生产补货策略的寻优算法.理论和数值仿真分析表明,制造商应对采购价格较高、提前期较长或需求方差较大的零部件采用准时制生产补货方式,能够降低供应链库存成本,提高供应链利润.

An Inventory-Routing Problem with Pickups and Deliveries Arising in the Replenishment of Automated Teller Machines

NARCIS (Netherlands)

van Anholt, Roel G.; Coelho, Leandro C.; Laporte, Gilbert; Vis, Iris F. A.

The purpose of this paper is to introduce, model, and solve a rich multiperiod inventory-routing problem with pickups and deliveries motivated by the replenishment of automated teller machines in the Netherlands. Commodities can be brought to and from the depot, as well as being exchanged among

An inventory-routing problem with pickups and deliveries arising in the replenishment of automated teller machines

NARCIS (Netherlands)

Van Anholt, Roel G.; Coelho, Leandro C.; Laporte, Gilbert; Vis, Iris F.A.

2016-01-01

The purpose of this paper is to introduce, model, and solve a rich multiperiod inventory-routing problem with pickups and deliveries motivated by the replenishment of automated teller machines in the Netherlands. Commodities can be brought to and from the depot, as well as being exchanged among

Effects of gas periodic stimulation on key enzyme activity in gas double-dynamic solid state fermentation (GDD-SSF).

Science.gov (United States)

Chen, Hongzhang; Shao, Meixue; Li, Hongqiang

2014-03-05

The heat and mass transfer have been proved to be the important factors in air pressure pulsation for cellulase production. However, as process of enzyme secretion, the cellulase formation has not been studied in the view of microorganism metabolism and metabolic key enzyme activity under air pressure pulsation condition. Two fermentation methods in ATPase activity, cellulase productivity, weight lose rate and membrane permeability were systematically compared. Results indicated that gas double-dynamic solid state fermentation had no obviously effect on cell membrane permeability. However, the relation between ATPase activity and weight loss rate was linearly dependent with r=0.9784. Meanwhile, the results also implied that gas periodic stimulation had apparently strengthened microbial metabolism through increasing ATPase activity during gas double-dynamic solid state fermentation, resulting in motivating the production of cellulase by Trichoderma reesei YG3. Therefore, the increase of ATPase activity would be another crucial factor to strengthen fermentation process for cellulase production under gas double-dynamic solid state fermentation. Copyright © 2013 Elsevier Inc. All rights reserved.

Using the Min/Max Method for Replenishment of Picking Locations

Directory of Open Access Journals (Sweden)

Apsalons Raitis

2017-03-01

Full Text Available The irregularity of removing quantities from a definite picking location in a warehouse very often results in the stock out in the particular picking address. In practice, the Red Card principle is used to determine a critical level for each picking location when it is necessary to start the replenishment of stock in the picking address. The question is how to calculate an adequate critical level. The guidelines in this paper explain in detail the solution of the problem using the Min/Max stock control method and mathematical algorithms adjusted by authors. In order to check the validity of these mathematical algorithms of the Min/Max method, the simulation modelling has been also done and presented.

Diesel supply planning for offshore platforms by a mathematical model based on the vehicle routing problem with replenishment

Energy Technology Data Exchange (ETDEWEB)

Fiorot Astoures, H.; Alvarenga Rosa, R. de; Silva Rosa, A.

2016-07-01

Oil exploration in Brazil is mainly held by offshore platforms which require the supply of several products, including diesel to maintain its engines. One strategy to supply diesel to the platforms is to keep a vessel filled with diesel nearby the exploration basin. An empty boat leaves the port and goes directly to this vessel, then it is loaded with diesel. After that, it makes a trip to supply the platforms and when the boat is empty, it returns to the vessel to be reloaded with more diesel going to another trip. Based on this description, this paper proposes a mathematical model based on the Vehicle Routing Problem with Intermediate Replenishment Facilities (VRPIRF) to solve the problem. The purpose of the model is to plan the routes for the boats to meet the diesel requests of the platform. Given the fact that in the literature, papers about the VRPIRF are scarce and papers about the VRPIRF applied to offshore platforms were not found in the published papers, this paper is important to contribute with the evolution of this class of problem, bringing also a solution for a real application that is very important for the oil and gas business. The mathematical model was tested using the CPLEX 12.6. In order to assess the mathematical model, tests were done with data from the major Brazilian oil and gas company and several strategies were tested. (Author)

AN OPTIMAL REPLENISHMENT POLICY FOR DETERIORATING ITEMS WITH RAMP TYPE DEMAND UNDER PERMISSIBLE DELAY IN PAYMENTS

Directory of Open Access Journals (Sweden)

Dr. Sanjay Jain

2010-10-01

Full Text Available The aim of this paper is to develop an optimal replenishment policy for inventory models of deteriorating items with ramp type demand under permissible delay in payments. Deterioration of items begins on their arrival in stock.  An example is also presented to illustrate the application of developed model.

Value-based Q(s,S) policy for joint replenishments

DEFF Research Database (Denmark)

Johansen, Søren Glud; Thorstenson, Anders

replenishment order is issued, if the expected cost of ordering immediately according to the (s, S) policy is less than the expected cost of deferring the order until the next demand or until the level Q is reached. We use simulation to evaluate our policy. Applying the value-based Q(s, S) policy to a standard...... set of 12-item numerical examples from the literature, the long-run average cost of the best known solution is reduced by approximately 1%. Further examples are also investigated and in some cases for which the cost structure implies a high service level, the cost reduction exceeds 10% of the cost...

Short-period volcanic gas precursors to phreatic eruptions: Insights from Poás Volcano, Costa Rica

Science.gov (United States)

de Moor, Maarten; Aiuppa, Alessandro; Pacheco, Javier; Avard, Geoffroy; Kern, Christoph; Liuzzo, Marco; Martinez, Maria; Giudice, Gaetano; Fischer, Tobias P.

2016-01-01

Volcanic eruptions involving interaction with water are amongst the most violent and unpredictable geologic phenomena on Earth. Phreatic eruptions are exceptionally difficult to forecast by traditional geophysical techniques. Here we report on short-term precursory variations in gas emissions related to phreatic blasts at Poás volcano, Costa Rica, as measured with an in situ multiple gas analyzer that was deployed at the edge of the erupting lake. Gas emitted from this hyper-acid crater lake approaches magmatic values of SO2/CO2 1–6 days prior to eruption. The SO2 flux derived from magmatic degassing through the lake is measureable by differential optical absorption spectrometry (sporadic campaign measurements), which allows us to constrain lake gas output and input for the major gas species during eruptive and non-eruptive periods. We can further calculate power supply to the hydrothermal system using volatile mass balance and thermodynamics, which indicates that the magmatic heat flux into the shallow hydrothermal system increases from ∼27 MW during quiescence to ∼59 MW during periods of phreatic events. These transient pulses of gas and heat from the deeper magmatic system generate both phreatic eruptions and the observed short-term changes in gas composition, because at high gas flux scrubbing of sulfur by the hydrothermal system is both kinetically and thermodynamically inhibited whereas CO2gas is always essentially inert in hyperacid conditions. Thus, the SO2/CO2 of lake emissions approaches magmatic values as gas and power supply to the sub-limnic hydrothermal system increase, vaporizing fluids and priming the hydrothermal system for eruption. Our results suggest that high-frequency real-time gas monitoring could provide useful short-term eruptive precursors at volcanoes prone to phreatic explosions.

Dynamic replenishment, production, and pricing decisions in the face of supply disruption and random price-sensitive demand

NARCIS (Netherlands)

Zhu, Stuart X.

2013-01-01

We study a joint decision problem for replenishment, production, pricing strategies in the face of both supply and demand uncertainties. The supply of the raw material suffers from a potential supply disruption while the demand for the finished goods is price-sensitive and random. We assume that the

Relationship between starch and lipid accumulation induced by nutrient depletion and replenishment in the microalga Parachlorella kessleri

Czech Academy of Sciences Publication Activity Database

Fernandes, B.; Teixeira, J.; Dragone, G.; Vicente, A. A.; Kawano, S.; Bišová, Kateřina; Přibyl, Pavel; Zachleder, Vilém; Vítová, Milada

2013-01-01

Roč. 144, SEP 2013 (2013), s. 268-274 ISSN 0960-8524 R&D Projects: GA MŠk LH12145; GA TA ČR TE01020080 Institutional support: RVO:61388971 ; RVO:67985939 Keywords : Lipids * Nutrient depletion * Nutrient replenishment Subject RIV: EE - Microbiology, Virology Impact factor: 5.039, year: 2013

Nectar replenishment maintains the neutral effects of nectar robbing on female reproductive success of Salvia przewalskii (Lamiaceae), a plant pollinated and robbed by bumble bees.

Science.gov (United States)

Ye, Zhong-Ming; Jin, Xiao-Fang; Wang, Qing-Feng; Yang, Chun-Feng; Inouye, David W

2017-04-01

It has been suggested that the dynamics of nectar replenishment could differ for flowers after being nectar robbed or visited legitimately, but further experimental work is needed to investigate this hypothesis. This study aimed to assess the role of nectar replenishment in mediating the effects of nectar robbing on pollinator behaviour and plant reproduction. Plant-robber-pollinator interactions in an alpine plant, Salvia przewalskii , were studied. It is pollinated by long-tongued Bombus religiosus and short-tongued B. friseanus , but robbed by B. friseanus . Nectar production rates for flowers after they were either robbed or legitimately visited were compared, and three levels of nectar robbing were created to detect the effects of nectar robbing on pollinator behaviour and plant reproduction. Nectar replenishment did not differ between flowers that had been robbed or legitimately visited. Neither fruit set nor seed set was significantly affected by nectar robbing. In addition, nectar robbing did not significantly affect visitation rate, flowers visited within a plant per foraging bout, or flower handling time of the legitimate pollinators. However, a tendency for a decrease in relative abundance of the pollinator B. religiosus with an increase of nectar robbing was found. Nectar robbing did not affect female reproductive success because nectar replenishment ensures that pollinators maintain their visiting activity to nectar-robbed flowers. Nectar replenishment might be a defence mechanism against nectar robbing to enhance reproductive fitness by maintaining attractiveness to pollinators. Further studies are needed to reveal the potential for interference competition among bumble bees foraging as robbers and legitimate visitors, and to investigate variation of nectar robbing in communities with different bumble bee species composition. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For

Optimal dynamic pricing and replenishment policies for deteriorating items

Directory of Open Access Journals (Sweden)

Masoud Rabbani

2014-08-01

Full Text Available Marketing strategies and proper inventory replenishment policies are often incorporated by enterprises to stimulate demand and maximize profit. The aim of this paper is to represent an integrated model for dynamic pricing and inventory control of deteriorating items. To reflect the dynamic characteristic of the problem, the selling price is defined as a time-dependent function of the initial selling price and the discount rate. In this regard, the price is exponentially discounted to compensate negative impact of the deterioration. The planning horizon is assumed to be infinite and the deterioration rate is time-dependent. In addition to price, the demand rate is dependent on advertisement as a powerful marketing tool. Several theoretical results and an iterative solution algorithm are developed to provide the optimal solution. Finally, to show validity of the model and illustrate the solution procedure, numerical results are presented.

Enceladus' near-surface CO2 gas pockets and surface frost deposits

Science.gov (United States)

Matson, Dennis L.; Davies, Ashley Gerard; Johnson, Torrence V.; Combe, Jean-Philippe; McCord, Thomas B.; Radebaugh, Jani; Singh, Sandeep

2018-03-01

Solid CO2 surface deposits were reported in Enceladus' South Polar Region by Brown et al. (2006). They noted that such volatile deposits are temporary and posited ongoing replenishment. We present a model for this replenishment by expanding on the Matson et al. (2012) model of subsurface heat and chemical transport in Enceladus. Our model explains the distributions of both CO2 frost and complexed CO2 clathrate hydrate as seen in the Cassini Visual and Infrared Mapping Spectrometer (VIMS) data. We trace the journey of CO2 from a subsurface ocean. The ocean-water circulation model of Matson et al. (2012) brings water up to near the surface where gas exsolves to form bubbles. Some of the CO2 bubbles are trapped and form pockets of gas in recesses at the bottom of the uppermost ice layer. When fissures break open these pockets, the CO2 gas is vented. Gas pocket venting is episodic compared to the more or less continuous eruptive plumes, emanating from the "tiger stripes", that are supported by plume chambers. Two styles of gas pocket venting are considered: (1) seeps, and (2) blowouts. The presence of CO2 frost patches suggests that the pocket gas slowly seeped through fractured, cold ice and when some of the gas reached the surface it was cold enough to condense (i.e., T ∼70 to ∼119 K). If the fissure opening is large, a blowout occurs. The rapid escape of gas and drop in pocket pressure causes water in the pocket to boil and create many small aerosol droplets of seawater. These may be carried along by the erupting gas. Electrically charged droplets can couple to the magnetosphere, and be dragged away from Enceladus. Most of the CO2 blowout gas escapes from Enceladus and the remainder is distributed globally. However, CO2 trapped in a clathrate structure does not escape. It is much heavier and slower moving than the CO2 gas. Its motion is ballistic and has an average range of about 17 km. Thus, it contributes to deposits in the vicinity of the vent. Local heat

Replenishment of system spares for improved economic performance

International Nuclear Information System (INIS)

McVay, J.L.; Gray, G.

1990-01-01

The nuclear industry continues to be faced with increasing external pressures that contribute to escalating production costs. In the past, regulatory and political pressures have been the chief sources for the authors concern. Today, however, the economic aspects for power generation may present an equal or an even greater challenge to the industry's stability. For nuclear utilities to survive and prosper, they must become more cost conscious and competitive. This challenge becomes even more important when one considers the growing number of cogeneration facilities, new independent power producers, and neighboring utilities all competing for the customer on a cost basis. This paper addresses opportunities created by the development of recent industry guidelines addressing engineering analysis techniques to be used during replenishment of system spares and components. This activity, while it has not been traditionally thought of as an engineering activity, can contribute significantly to the reduction of operation and maintenance (O and M) costs for plant systems and will help nuclear utilities to aggressively battle the rising issue of cost control

Governing transitions: Cases and insights from two periods in the history of the UK gas industry

International Nuclear Information System (INIS)

Arapostathis, Stathis; Carlsson-Hyslop, Anna; Pearson, Peter J G; Thornton, Judith; Gradillas, Maria; Laczay, Scott; Wallis, Suzanne

2013-01-01

The paper aims to inform historically the analyses of future sociotechnical transition pathways in the electricity sector, particularly those developed by the Transition Pathways to a Low Carbon Economy project. It also aims to inform the theoretical approach to transitions by focusing on key decisions at ‘branching points’ that led to transitions in the UK gas energy services regime, which occurred under different governance patterns. The first historical case study covers the market-led transformation of the manufactured gas regime from 1877 to 1914, which developed the end-uses of gas beyond lighting to include cooking, and extended access to working class consumers. The second case study covers the period from 1948 to 1977, historically reconstructing the transition from town gas to natural gas. This state-led and coordinated conversion to natural gas was preceded by a period of destabilisation of the manufactured gas regime, the co-existence of several niche technologies and the hybridisation of the key actors and technological infrastructures of the incumbent regime. Comparing the cases provides insights for future energy service transitions by addressing the significance of power, trust and networking in the decision making processes involved in the governance of energy transitions. - Highlights: ► Historical work is useful in understanding socio-technical energy transitions. ► Different governance modes have led to transitions with different characteristics. ► Gas regimes operating under market and state ‘logics’ took decisions differently. ► Decisions at key branching points led to path dependency, affecting later decisions. ► Agency, governance and trust were important elements in the transitions analysed.

The duration of the transitory period of public gas distribution

International Nuclear Information System (INIS)

Gazzola, D.

2006-01-01

The article describes the interpretative problems concerning the duration of the transitory period of public gas distribution after law decree 273/05 came into effect. This decree is the third legislative measure which, in a period of five years, reforms the transitory provisions. The article outlines the normative background of legislative decree n. 164/00 (so called Letta decree) and law n. 239/04 (so called Marzano law) and it analyses their judicial interpretations. It then explains the changes introduced by law decree n. 273/05 and the new interpretative problems there might be with reference to this decree. The decree clarifies the due date of the transitory period and specifies that the date of 31st December 2005 is postponed to 31st December 2007. The Administrative Tribunal of Lombardia Region Brescia tried to limit the effects of law decree n. 273/05, stating that the new expiration date could not regard the contracts for which the local authorities had already acknowledged the previous due date. The State Council argued instead that the new law decree regards all the contracts. This decree also clarifies that the chances of increasing duration ex art. 15, comma 7, legislative decree n. 164/00, applies automatically, but it doesn't solve the interpretative problem concerning the possibility of adding up more than one of these chances. The article focuses on the problems of the public gas distribution after the reform of this sector with the implementation of directive n. 98/30/CE and it underlines that the various legislative measures of these years are indicative of the difficulty to allow a gradual transition towards a liberalized market. In this context, law decree n. 273/05 is the last legislative measure which tries to guarantee a balance between the rapid liberalization of the market, on one hand, and the interests of the firms which had contracts when the reform came into effect, on the other hand [it

Synthesis of Nanoparticles in a Pulsed-Periodic Gas Discharge and Their Potential Applications

Science.gov (United States)

Ivanov, V. V.; Efimov, A. A.; Myl'nikov, D. A.; Lizunova, A. A.

2018-03-01

Conditions for the synthesis of three types nanoparticles (SnO2, Al2O3, and Ag) with typical sizes in the range of 4 to 10 nm and a performance of 0.4 g/h are employed in a pulsed-periodic gas discharge in an atmosphere of air. Spherical Ge nanoparticles with a characteristic size of 13 nm are synthesized by these means for the first time with a performance of around 10 mg/h. The specific energy consumption in the synthesis of nanoparticles is for these materials in the range of 2000 to 5000 kW h/kg. The prospects for using tinoxide nanoparticles in sensor components and jets of silver nanoparticles for aerosol printing are discussed. The merits and demerits of the pulsed gas-discharge method among other gas-phase approaches to the synthesis of nanoparticles are analyzed for the current level of development.

Genetic connectivity and self-replenishment of inshore and offshore populations of the endemic anemonefish, Amphiprion latezonatus

KAUST Repository

Steinberg, Rosemary

2016-02-19

Globally, marine species are under increasing pressure from human activities, including ocean warming, acidification, pollution, and overfishing. Species most vulnerable to these pressures tend to be ecological specialists that have low abundance and small distribution ranges (endemics). Marine endemics often exist as meta-populations distributed among few isolated locations. Determining genetic connectivity among these locations is essential to understanding the recovery potential of endemics after local extinction events. This study examined connectivity in the endemic anemonefish, Amphiprion latezonatus, a habitat specialist with low abundance at most locations. Evolutionary and contemporary migration, genetic diversity, and self-replenishment among the four main locations (Sunshine Coast, North Solitary Island, Lord Howe Island, and Norfolk Island) that comprise the entire A. latezonatus geographic range were assessed using mtDNA and microsatellite markers. Though historical gene flow inferred from mtDNA appeared high, population genetic differentiation was evident and contemporary gene flow inferred from microsatellites was limited, alongside very high (≥89 %) self-replenishment at all locations. Together, these data suggest prolonged recovery times following severe population decline (or extirpation) and indicate a need to protect this species at all locations, particularly Norfolk Island and Sunshine Coast where marine protected areas are lacking.

Modeling and Optimization of the Multiobjective Stochastic Joint Replenishment and Delivery Problem under Supply Chain Environment

Directory of Open Access Journals (Sweden)

Lin Wang

2013-01-01

Full Text Available As a practical inventory and transportation problem, it is important to synthesize several objectives for the joint replenishment and delivery (JRD decision. In this paper, a new multiobjective stochastic JRD (MSJRD of the one-warehouse and n-retailer systems considering the balance of service level and total cost simultaneously is proposed. The goal of this problem is to decide the reasonable replenishment interval, safety stock factor, and traveling routing. Secondly, two approaches are designed to handle this complex multi-objective optimization problem. Linear programming (LP approach converts the multi-objective to single objective, while a multi-objective evolution algorithm (MOEA solves a multi-objective problem directly. Thirdly, three intelligent optimization algorithms, differential evolution algorithm (DE, hybrid DE (HDE, and genetic algorithm (GA, are utilized in LP-based and MOEA-based approaches. Results of the MSJRD with LP-based and MOEA-based approaches are compared by a contrastive numerical example. To analyses the nondominated solution of MOEA, a metric is also used to measure the distribution of the last generation solution. Results show that HDE outperforms DE and GA whenever LP or MOEA is adopted.

Synchronization of construction, replenishment and leasing cycles with account of wave dynamics of innovation cycles in the construction and transport field

Science.gov (United States)

Alekseeva, Tatyana

2017-10-01

The article considers the contradictive nature of the basic cycles of the growth in construction, the core of which are construction cycles, replenishment cycles of the active part of fixed assets, innovation and investment cycles. All of the listed cycles objectively thwart the science and technology progress in construction. There are presented results of the study of finance leasing as an effective tool, that provides time reduction of the innovation replenishment cycle of the active part of fixed assets in construction. It takes into account the development and implementation terms of construction investment projects in order to timely support the innovation wave and enhance its efficiency in construction for a rapid transition of the construction investment complex and national economy to a new vector of growth.

An Optimization Framework for Combining the Petroleum Replenishment Problem with the Optimal Bidding in Combinatorial Auctions

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Chefi Triki

2016-08-01

Full Text Available We address in this paper a periodic petroleum station replenishment problem (PPSRP that aims to plan the delivery of petroleum products to a set of geographically dispatched stations. It is assumed that each station is characterized by its weekly demand and by its frequency of service. The main objective of the delivery process is to minimize the total travelled distance by the vailable trucks over an extended planning horizon. The problem configuration is described through a set of trucks with several compartments each and a set of stations with demands and prefixed delivery frequencies. Given such input data, the minimization of the total distance is subject to assignment and routing constraints that express the capacity limitations of each truck's compartment in terms of the frequency and the pathways' restrictions. In this paper, we develop and solve the full space mathematical formulation for the PPSRP with application to the Omani context. Our ultimate aim is to include such a model into an integrated framework having the objective of advising petroleum distribution companies on how to prepare bids in case of participation in combinatorial auctions of the transportation procurement.

Nigral dopaminergic neuron replenishment in adult mice through VE-cadherin-expressing neural progenitor cells

Directory of Open Access Journals (Sweden)

Abir A Rahman

2017-01-01

Full Text Available The function of dopaminergic neurons in the substantia nigra is of central importance to the coordination of movement by the brain's basal ganglia circuitry. This is evidenced by the loss of these neurons, resulting in the cardinal motor deficits associated with Parkinson's disease. In order to fully understand the physiology of these key neurons and develop potential therapies for their loss, it is essential to determine if and how dopaminergic neurons are replenished in the adult brain. Recent work has presented evidence for adult neurogenesis of these neurons by Nestin+/Sox2– neural progenitor cells. We sought to further validate this finding and explore a potential atypical origin for these progenitor cells. Since neural progenitor cells have a proximal association with the vasculature of the brain and subsets of endothelial cells are Nestin+, we hypothesized that dopaminergic neural progenitors might share a common cell lineage. Therefore, we employed a VE-cadherin promoter-driven CREERT2:THlox/THlox transgenic mouse line to ablate the tyrosine hydroxylase gene from endothelial cells in adult animals. After 26 weeks, but not 13 weeks, following the genetic blockade of tyrosine hydroxylase expression in VE-cadherin+ cells, we observed a significant reduction in tyrosine hydroxylase+ neurons in the substantia nigra. The results from this genetic lineage tracing study suggest that dopaminergic neurons are replenished in adult mice by a VE-cadherin+ progenitor cell population potentially arising from an endothelial lineage.

Optimal diving behaviour and respiratory gas exchange in birds.

Science.gov (United States)

Halsey, Lewis G; Butler, Patrick J

2006-11-01

This review discusses the advancements in our understanding of the physiology and behaviour of avian diving that have been underpinned by optimal foraging theory and the testing of optimal models. To maximise their foraging efficiency during foraging periods, diving birds must balance numerous factors that are directly or indirectly related to the replenishment of the oxygen stores and the removal of excess carbon dioxide. These include (1) the time spent underwater (which diminishes the oxygen supply, increases carbon dioxide levels and may even include a build up of lactate due to anaerobic metabolism), (2) the time spent at the surface recovering from the previous dive and preparing for the next (including reloading their oxygen supply, decreasing their carbon dioxide levels and possibly also metabolising lactate) and (3) the trade-off between maximising oxygen reserves for consumption underwater by taking in more air to the respiratory system, and minimising the energy costs of positive buoyancy caused by this air, to maximise the time available underwater to forage. Due to its importance in avian diving, replenishment of the oxygen stores has become integral to models of optimal diving, which predict the time budgeting of animals foraging underwater. While many of these models have been examined qualitatively, such tests of predictive trends appear fallible and only quantifiable support affords strong evidence of their predictive value. This review describes how the quantification of certain optimal diving models, using tufted ducks, indeed demonstrates some predictive success. This suggests that replenishment of the oxygen stores and removal of excess carbon dioxide have significant influences on the duration of the surface period between dives. Nevertheless, present models are too simplistic to be robust predictors of diving behaviour for individual animals and it is proposed that they require refinement through the incorporation of other variables that also

Effect of gas heating on the generation of an ultrashort avalanche electron beam in the pulse-periodic regime

Science.gov (United States)

Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Sorokin, D. A.; Tarasenko, V. F.

2015-07-01

The generation of an ultrashort avalanche electron beam (UAEB) in nitrogen in the pulse-periodic regime is investigated. The gas temperature in the discharge gap of the atmospheric-pressure nitrogen is measured from the intensity distribution of unresolved rotational transitions ( C 3Π u , v' = 0) → ( B 3Π g , v″ = 0) in the nitrogen molecule for an excitation pulse repetition rate of 2 kHz. It is shown that an increase in the UAEB current amplitude in the pulse-periodic regime is due to gas heating by a series of previous pulses, which leads to an increase in the reduced electric field strength as a result of a decrease in the gas density in the zone of the discharge formation. It is found that in the pulse-periodic regime and the formation of the diffuse discharge, the number of electrons in the beam increases by several times for a nitrogen pressure of 9 × 103 Pa. The dependences of the number of electrons in the UAEB on the time of operation of the generator are considered.

Effect of medium replenishment or composition on [3H] thymidine incorporation in uv-irradiated CHO-K1 cells

International Nuclear Information System (INIS)

Newman, C.N.; Miller, J.H.

1985-03-01

Because culture medium contains uv-absorbing material, it is usually removed just before uv-irradiation of tissue culture monolayers. However, medium removal and replenishment with fresh medium alone (sham-irradiation) causes up to a 10-fold reduction in the rate of [ 3 H]TdR incorporation in CHO-K1 cells which persists for several hours. This reduction, which is much smaller ( 3 H]TdR pulse-label in conditioned (spent) and in fresh medium; TdR in the former is converted by cells to thymine. When responses of uv-irradiated cells are normalized to responses of corresponding sham-irradiated cultures, considerable variation is observed in replicate experiments because fresh medium appears to induce transient metabolic imbalances in irradiated cells which are not readily controlled. This problem can, in part, be circumvented by replenishing treated cultures with the original spent medium; however, the presence of CdR in the growth medium still causes an anomalous 2-3-fold greater uv-induced reduction in [ 3 H]TdR incorporation than is observed in the absence of CdR. 17 refs., 3 figs., 1 tab

THE EFFECT OF INSULIN AND CARBOHYDRATE SUPPLEMENTATION ON GLYCOGEN REPLENISHMENT AMONG DIFFERENT HINDLIMB MUSCLES IN RATS FOLLOWING PROLONGED SWIMMING

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Mei-Chich Hsu

2012-04-01

Full Text Available In the present study we investigated the interactive effects of insulin and carbohydrate on glycogen replenishment in different rat hindlimb muscles. Forty male Sprague Dawley rats were assigned to 5 groups, including 1 sedentary control with carbohydrate supplement (2 g glucose · kg body wt-1, 2 sedentary rats with 16 hours recovery, carbohydrate and insulin (0.5 U · kg body wt-1, 3 swimming without recovery, 4 swimming with 16 hours recovery and carbohydrate supplement, and 5 swimming with 16 hours recovery, carbohydrate and insulin. The swimming protocol consisted of two 3 h swimming sections, which were separated by a 45 min rest. The insulin and carbohydrate were administered to the rats immediately after exercise. At the end of the experiment, the soleus (S, plantaris (P, quadriceps (Q and gastrocnemius (G were surgically excised to evaluate glycogen utilization and replenishment. We observed that glycogen utilization was significantly lower in G and Q than S and P during swimming (p <0.05, and S showed the greatest capacity of glycogen resynthesis after post-exercise recovery (p <0.05. In the sedentary state, the glycogen synthesis did not differ among hindlimb muscles during insulin and carbohydrate treatments. Interestingly, with insulin and carbohydrate, the glycogen resynthesis in S and P were significantly greater than in Q and G following post-exercise recovery (p <0.05. We therefore concluded that the soleus and plantaris are the primary working muscles during swimming, and the greatest glycogen replenishment capacity of the soleus during post-exercise recovery is likely due to its highest insulin sensitivity.

Magnetoresistance calculations for a two-dimensional electron gas with unilateral short-period strong modulation

Czech Academy of Sciences Publication Activity Database

Výborný, Karel; Smrčka, Ludvík

2002-01-01

Roč. 66, č. 20 (2002), s. 205318-1 - 205318-8 ISSN 0163-1829 R&D Projects: GA ČR GA202/01/0754 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetoresistance * short-period superlattices * two-dimensional electron gas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.327, year: 2002

NAD(+) Replenishment Improves Lifespan and Healthspan in Ataxia Telangiectasia Models via Mitophagy and DNA Repair

DEFF Research Database (Denmark)

Fang, Evandro Fei; Kassahun, Henok; Croteau, Deborah L

2016-01-01

and neurodegeneration in A-T patients is unclear. Here we report and examine the significance of increased PARylation, low NAD(+), and mitochondrial dysfunction in ATM-deficient neurons, mice, and worms. Treatments that replenish intracellular NAD(+) reduce the severity of A-T neuropathology, normalize neuromuscular...... function, delay memory loss, and extend lifespan in both animal models. Mechanistically, treatments that increase intracellular NAD(+) also stimulate neuronal DNA repair and improve mitochondrial quality via mitophagy. This work links two major theories on aging, DNA damage accumulation, and mitochondrial...

One-Way Flow of a Rarefied Gas Induced in a Circular Pipe with a Periodic Temperature Distribution

National Research Council Canada - National Science Library

Aoki, K

2000-01-01

The steady behavior of a rarefied gas in a circular pipe with a saw-like temperature distribution increasing and decreasing periodically in the direction of the pipe axis is investigated numerically...

Exact dynamics of a one dimensional Bose gas in a periodic time-dependent harmonic trap

Science.gov (United States)

Scopa, Stefano; Unterberger, Jéremie; Karevski, Dragi

2018-05-01

We study the unitary dynamics of a 1D gas of hard-core bosons trapped into a harmonic potential which varies periodically in time with frequency . Such periodic systems can be classified into orbits of different monodromies corresponding to two different physical situations, namely the case in which the bosonic cloud remains stable during the time-evolution and the case where it turns out to be unstable. In the present work we derive in the large particle number limit exact results for the stroboscopic evolution of the energy and particle densities in both physical situations.

Process for the production of high purity deuterium

International Nuclear Information System (INIS)

Arrathoon, R.

1977-01-01

A process for the electrolysis of heavy water which results in the production of high purity deuterium without periodic replenishment of the electrolyte with additional deuterated compounds is defined. Electrolysis is effected through the use of an inexpensive cation-action permselective membrane which is essentially a solid polymer electrolyte and which is capable of automatically separating the evolved deuterium and oxygen gas. This cation-active permselective membrane does not introduce any intrinsic impurities or tritium contamination in the generated deuterium gas, does not require periodic revitalization with deuterated compounds or other chemical compounds, and is characterized by an unusually high electrical efficiency

Comparing and contrasting Holocene and Eemian warm periods with greenhouse-gas-induced warming

International Nuclear Information System (INIS)

MacCracken, M.C.; Kutzbach, J.

1990-01-01

Periods of the past that are estimated to have been warmer than present are of great potential interest for comparison with simulations of future climates associated with greenhouse-gas-induced warming. Certain features of the climates of the mid-Holocene and Eemian periods, both interglacial maxima, are described. The simulated climatic responses to both types of forcing, in terms of land/ocean and latitudinal averages, are also compared. The zonal average and annual (or seasonal) average radiation fluxes associated with the different-from-present orbital conditions that existed for those interglacials are compared to the radiation flux associated with CO 2 -induced warming. There are some similarities but also significant differences in the two types of radiation flux perturbations, and there are both similarities and differences in the simulated climatic responses

Constraining the Dynamics of Periodic Behavior at Mt. Semeru, Indonesia, Combining Numerical Modeling and Field Measurements of Gas emission

Science.gov (United States)

Smekens, J.; Clarke, A. B.; De'Michieli Vitturi, M.; Moore, G. M.

2012-12-01

Mt. Semeru is one of the most active explosive volcanoes on the island of Java in Indonesia. The current eruption style consists of small but frequent explosions and/or gas releases (several times a day) accompanied by continuous lava effusion that sporadically produces block-and-ash flows down the SE flank of the volcano. Semeru presents a unique opportunity to investigate the magma ascent conditions that produce this kind of persistent periodic behavior and the coexistence of explosive and effusive eruptions. In this work we use DOMEFLOW, a 1.5D transient isothermal numerical model, to investigate the dynamics of lava extrusion at Semeru. Petrologic observations from tephra and ballistic samples collected at the summit help us constrain the initial conditions of the system. Preliminary model runs produced periodic lava extrusion and pulses of gas release at the vent, with a cycle period on the order of hours, even though a steady magma supply rate was prescribed at the bottom of the conduit. Enhanced shallow permeability implemented in the model appears to create a dense plug in the shallow subsurface, which in turn plays a critical role in creating and controlling the observed periodic behavior. We measured SO2 fluxes just above the vent, using a custom UV imaging system. The device consists of two high-sensitivity CCD cameras with narrow UV filters centered at 310 and 330 nm, and a USB2000+ spectrometer for calibration and distance correction. The method produces high-frequency flux series with an accurate determination of the wind speed and plume geometry. The model results, when combined with gas measurements, and measurements of sulfur in both the groundmass and melt inclusions in eruptive products, could be used to create a volatile budget of the system. Furthermore, a well-calibrated model of the system will ultimately allow the characteristic periodicity and corresponding gas flux to be used as a proxy for magma supply rate.

An Innovative Heuristic in Multi-Item Replenishment Problem for One Warehouse and N Retailers

Directory of Open Access Journals (Sweden)

Yugowati Praharsi

2014-01-01

Full Text Available Joint replenishment problem (JRP is a type of inventory model which aims to minimize the total inventory cost consisting of major ordering cost, minor ordering cost and inventory holding cost. Different from previous papers, this study considers one warehouse, multi items and N retailers. An innovative heuristic approach is developed to solve the problem. In this paper, we consider a multi echelon inventory system and seek to find a balance between the order cost and the inventory holding costs at each installation. The computational results show that the innovative heuristic provides a near exact optimal solution, but is more efficient in terms of the computational time and the iteration number.

Field and Experimental Constraints on the Dynamics of Replenished Silicic Magma Chambers

Science.gov (United States)

Bain, A. A.; Jellinek, M.

2008-12-01

The underlying causes of catastrophic caldera-forming volcanic eruptions remain poorly understood. However, the occurrence of magma mixing within bimodal systems has become increasingly linked with such eruptions. In particular, buoyancy effects related to unstable density contrasts arising as a result of silicic- basaltic magma interactions may play an important role in the growth, differentiation and catastrophic eruption of silicic magma chambers. Evidence of such magmatic interactions can be found in layered intrusions from the Coastal Maine Magmatic Province (USA), where well-exposed cross-sections reveal hundreds of laterally-extensive basaltic sheets, apparently injected as intrusive lava flows onto the growing floors of silicic magma chambers. Interfaces between mafic and silicic layers are commonly sharply defined and exhibit deformation parallel to the inferred direction of palaeo-gravity. Our field observations suggest that the cooling, settling and buckling of gravitationally-unstable mafic replenishments may have driven large-scale (basalt layer depth) and small- scale (crystal diameter) upwelling and/or overturning of underlying buoyant silicic cumulate material. In order to characterize the full range of buoyancy effects, we carried out extensive spectral analysis of high- resolution digital field measurements from the Pleasant Bay and Mount Desert Island intrusions. In many cases, Rayleigh-Taylor theory and the longest measured wavelength of deformation indicate that a large and potentially-quantifiable fraction of the original, pre-replenishment silicic cumulate thickness may be missing, implying that vertical mass transfer has occurred. In addition, the shortest wavelengths of deformation are generally consistent with observed length-scales of crystals and clumps of crystals at these localities. With the aim of understanding the initial conditions that gave rise to these field observations, we conduct a series of laboratory experiments in which we

DDeveloping and solving a bi-objective joint replenishment problem under storing space constraint

Directory of Open Access Journals (Sweden)

ommolbanin yousefi

2011-03-01

Full Text Available In this research, a bi-objective joint replenishment problem has been developed and solved with the assumption of one restricted resource. The proposed model has a storing space constraint and tries to optimize two objective functions simultaneously. They include minimizing annual holding and setup costs and minimizing annual inventory investment. Then, for solving this problem, a multi-objective genetic algorithm (MOGA has been developed. In order to analyze the algorithm efficiency, its performance has been examined in solving 1600 randomly produced problems using parameters extracted from literature. The findings imply that the proposed algorithm is capable of producing a good set of Pareto optimal solutions. Finally, the application of the problem solving approach and the findings of the proposed algorithm have been illustrated for a special problem, which has been randomly produced.

A passive method for the determination of the equilibrium factor between radon gas and its short period progeny

International Nuclear Information System (INIS)

Lopez, Fabio O.; Canoba, Analia C.

2001-01-01

Due to the radiological importance of 222 Rn gas and its progeny of short period it is extremely necessary to count with an adequate methodology for the determination of its concentration in the different atmospheres in which human activity is developed. In this work a method was developed to determine the concentration of 222 Rn gas and the equilibrium factor between the concentration of the gas and its descendants, by means of a single device that has two Makrofol passive tracks detector. This device is completely passive and integrating, conditions that make it very appropriate to be used in any atmospheres in which human activity is developed, for example in houses, schools, places of work, underground mines, etc. (author)

The Dangers of 'Warming and Replenishing' (wenbu ) during the Ming to Qing Epistemic Transition.

Science.gov (United States)

de Vries, Leslie

2015-01-01

Through a case study of Zhao Xianke's One Principle through Medicine ( Yiguan ) (1617?) and Xu Dachun's (1693-1771) denouncements of this text, my article zooms in on divergent discourses on the safety and efficacy of medicinal substances and compounds in late imperial China. Although Xu Dachun's fierce attacks on the popular 'warming and replenishing' ( wenbu ) therapies can be situated in an epistemic shift from the cosmology of 'Song learning' ( songxue ) towards the philology of 'Han learning' ( hanxue ) and 'evidential research' ( kaozheng ), I argue that more complex issues were at stake as well. Changed political, social, ethical, and economic realities shaped new and multifaceted perceptions of the nature of medicine, the medical profession, and the usage of medicinals in the aftermath of the Ming to Qing transition.

Method and apparatus for replenishing the helium bath in the rotor of a superconducting generator

International Nuclear Information System (INIS)

Hofmann, A.; Schnapper, C.

1980-01-01

In order to replenish a helium bath in the super-conducting rotor of an electrical machine, in which bath liquid helium boils at subatmospheric pressure, with liquid helium from a helium reservoir, the liquid helium in the reservoir being at ambient pressure and a part of the liquid helium changing to the vapor phase during flow from the reservoir to the bath, liquid helium is introduced into the bath at a distance from the rotor axis of rotation, the liquid and vapor phases of the helium flowing from the reservoir to the bath are separated from one another in a phase separator fixed to the rotor, and the separated vapor phase is extracted from the separator. (MM) [de

Cold Molecular Gas Along the Merger Sequence in Local Luminous Infrared Galaxies

Science.gov (United States)

Yamashita, Takuji; Komugi, Shinya; Matsuhara, Hideo; Armus, Lee; Inami, Hanae; Ueda, Junko; Iono, Daisuke; Kohno, Kotaro; Evans, Aaron S.; Arimatsu, Ko

2017-08-01

We present an initial result from the 12CO (J = 1-0) survey of 79 galaxies in 62 local luminous and ultraluminous infrared galaxy (LIRG and ULIRG) systems obtained using the 45 m telescope at the Nobeyama Radio Observatory. This is a systematic 12CO (J = 1-0) survey of the Great Observatories All-sky LIRGs Survey (GOALS) sample. The molecular gas mass of the sample is in the range 2.2× {10}8{--}7.0× {10}9 {M}⊙ within the central several kiloparsecs subtended by the 15\\prime\\prime beam. A method to estimate the size of a CO gas distribution is introduced, which is combined with the total CO flux in the literature. This method is applied to part of our sample, and we find that the median CO radius is 1-4 kpc. From the early stage to the late stage of mergers, we find that the CO size decreases while the median value of the molecular gas mass in the central several-kiloparsec region is constant. Our results statistically support a scenario where molecular gas inflows toward the central region from the outer disk to replenish gas consumed by starburst, and that such a process is common in merging LIRGs.

Closed cycle high-repetition-rate pulsed HF laser

Science.gov (United States)

Harris, Michael R.; Morris, A. V.; Gorton, Eric K.

1997-04-01

The design and performance of a closed cycle high repetition rate HF laser is described. A short pulse, glow discharge is formed in a 10 SF6:1 H2 gas mixture at a total pressure of approximately 110 torr within a 15 by 0.5 by 0.5 cm3 volume. Transverse, recirculated gas flow adequate to enable repetitive operation up to 3 kHz is imposed by a centrifugal fan. The fan also forces the gas through a scrubber cell to eliminate ground state HF from the gas stream. An automated gas make-up system replenishes spent gas removed by the scrubber. Typical mean laser output powers up to 3 W can be maintained for extended periods of operation.

Human exposure to unconventional natural gas development: A public health demonstration of periodic high exposure to chemical mixtures in ambient air.

Science.gov (United States)

Brown, David R; Lewis, Celia; Weinberger, Beth I

2015-01-01

Directional drilling and hydraulic fracturing of shale gas and oil bring industrial activity into close proximity to residences, schools, daycare centers and places where people spend their time. Multiple gas production sources can be sited near residences. Health care providers evaluating patient health need to know the chemicals present, the emissions from different sites and the intensity and frequency of the exposures. This research describes a hypothetical case study designed to provide a basic model that demonstrates the direct effect of weather on exposure patterns of particulate matter smaller than 2.5 microns (PM2.5) and volatile organic chemicals (VOCs). Because emissions from unconventional natural gas development (UNGD) sites are variable, a short term exposure profile is proposed that determines 6-hour assessments of emissions estimates, a time scale needed to assist physicians in the evaluation of individual exposures. The hypothetical case is based on observed conditions in shale gas development in Washington County, Pennsylvania, and on estimated emissions from facilities during gas development and production. An air exposure screening model was applied to determine the ambient concentration of VOCs and PM2.5 at different 6-hour periods of the day and night. Hourly wind speed, wind direction and cloud cover data from Pittsburgh International Airport were used to calculate the expected exposures. Fourteen months of daily observations were modeled. Higher than yearly average source terms were used to predict health impacts at periods when emissions are high. The frequency and intensity of exposures to PM2.5 and VOCs at a residence surrounded by three UNGD facilities was determined. The findings show that peak PM2.5 and VOC exposures occurred 83 times over the course of 14 months of well development. Among the stages of well development, the drilling, flaring and finishing, and gas production stages produced higher intensity exposures than the

Parity Bit Replenishment for JPEG 2000-Based Video Streaming

Directory of Open Access Journals (Sweden)

François-Olivier Devaux

2009-01-01

Full Text Available This paper envisions coding with side information to design a highly scalable video codec. To achieve fine-grained scalability in terms of resolution, quality, and spatial access as well as temporal access to individual frames, the JPEG 2000 coding algorithm has been considered as the reference algorithm to encode INTRA information, and coding with side information has been envisioned to refresh the blocks that change between two consecutive images of a video sequence. One advantage of coding with side information compared to conventional closed-loop hybrid video coding schemes lies in the fact that parity bits are designed to correct stochastic errors and not to encode deterministic prediction errors. This enables the codec to support some desynchronization between the encoder and the decoder, which is particularly helpful to adapt on the fly pre-encoded content to fluctuating network resources and/or user preferences in terms of regions of interest. Regarding the coding scheme itself, to preserve both quality scalability and compliance to the JPEG 2000 wavelet representation, a particular attention has been devoted to the definition of a practical coding framework able to exploit not only the temporal but also spatial correlation among wavelet subbands coefficients, while computing the parity bits on subsets of wavelet bit-planes. Simulations have shown that compared to pure INTRA-based conditional replenishment solutions, the addition of the parity bits option decreases the transmission cost in terms of bandwidth, while preserving access flexibility.

Effects of dry period length on production, cash flows and greenhouse gas emissions of the dairy herd: A dynamic stochastic simulation model.

Directory of Open Access Journals (Sweden)

Akke Kok

Full Text Available Shortening or omitting the dry period of dairy cows improves metabolic health in early lactation and reduces management transitions for dairy cows. The success of implementation of these strategies depends on their impact on milk yield and farm profitability. Insight in these impacts is valuable for informed decision-making by farmers. The aim of this study was to investigate how shortening or omitting the dry period of dairy cows affects production and cash flows at the herd level, and greenhouse gas emissions per unit of milk, using a dynamic stochastic simulation model. The effects of dry period length on milk yield and calving interval assumed in this model were derived from actual performance of commercial dairy cows over multiple lactations. The model simulated lactations, and calving and culling events of individual cows for herds of 100 cows. Herds were simulated for 5 years with a dry period of 56 (conventional, 28 or 0 days (n = 50 herds each. Partial cash flows were computed from revenues from sold milk, calves, and culled cows, and costs from feed and rearing youngstock. Greenhouse gas emissions were computed using a life cycle approach. A dry period of 28 days reduced milk production of the herd by 3.0% in years 2 through 5, compared with a dry period of 56 days. A dry period of 0 days reduced milk production by 3.5% in years 3 through 5, after a dip in milk production of 6.9% in year 2. On average, dry periods of 28 and 0 days reduced partial cash flows by €1,249 and €1,632 per herd per year, and increased greenhouse gas emissions by 0.7% and 0.5%, respectively. Considering the potential for enhancing cow welfare, these negative impacts of shortening or omitting the dry period seem justifiable, and they might even be offset by improved health.

NOT DEAD YET: COOL CIRCUMGALACTIC GAS IN THE HALOS OF EARLY-TYPE GALAXIES

International Nuclear Information System (INIS)

Thom, Christopher; Tumlinson, Jason; Sembach, Kenneth R.; Werk, Jessica K.; Xavier Prochaska, J.; Oppenheimer, Benjamin D.; Peeples, Molly S.; Tripp, Todd M.; Katz, Neal S.; O'Meara, John M.; Ford, Amanda Brady; Davé, Romeel; Weinberg, David H.

2012-01-01

We report new observations of circumgalactic gas in the halos of early-type galaxies (ETGs) obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. We find that detections of H I surrounding ETGs are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations. For ETGs, the covering fraction for H I absorption above 10 16 cm –2 is ∼40%-50% within ∼150 kpc. Line widths and kinematics of the detected material show it to be cold (T ∼ 5 K) in comparison to the virial temperature of the host halos. The implied masses of cool, photoionized circumgalactic medium baryons may be up to 10 9 -10 11 M ☉ . Contrary to some theoretical expectations, strong halo H I absorbers do not disappear as part of the quenching of star formation. Even passive galaxies retain significant reservoirs of halo baryons that could replenish the interstellar gas reservoir and eventually form stars. This halo gas may feed the diffuse and molecular gas that is frequently observed inside ETGs.

[Experimental study on the treatment of serious soft tissue injuries with strengthening the spleen and replenishing qi].

Science.gov (United States)

Chen, Xun-wen; Zhu, Yong-zhan; Chen, Zhi-wei; Wu, Zheng-jie; He, Li-lei

2008-09-01

To study the effects of Chinese drugs based on strengthening the spleen and replenishing qi treatment rule on neoformative capillaries and fibroblast during the soft tissue repair after serious trauma in rats, so as to explore the biological basis of the TCM theory "the spleen dominate extremities and muscles" applied to the treatment of soft tissue injuries. The model rats were established by bleeding from femoral artery and lancing method, and the rats were randomly divided into the control group, strengthening the spleen group and activating blood and resolving stasis group. The samples were got from the tissue of the wounded area at the 5th, 10th and 15th days after oral administration of the traditional Chinese medicine. After fixation and section, the tissues were stained by CD31 and PCNA staining. The amount of the capillaries and fibroblasts in the tissue of the wounded area were observed through multi-purpose microscope (ZEISS Axioskop2). Quantitative analysis was carried out on Image-ProPlus image analyzer. The amount of the capillaries and fibroblasts in the wounded tissue in the strengthening the spleen group were larger than that in the control group at the 5th, 10th and 15th day. And the proliferation speed of capillaries and fibroblasts was faster than those in the control group or the activating blood and resolving stasis group. The Chinese drugs according to strengthening the spleen and replenishing qi treatment rule were effective to promote growth of the granulation tissue and facilitate healing of the wounded area. And it has better effect than the treatment of promoting blood circulation and removing stasis.

Natural gas to start long period of growth during next 3 years

International Nuclear Information System (INIS)

Anon.

1993-01-01

Pressures are building worldwide to increase consumption of natural gas. During the past decade, worldwide marketed production of natural gas has moved up much faster than oil and coal production. Gas output increased from 51.8 tcf in 1982 to 72.1 tcf in 1992. This 39.2% production increase compares with gains of 13.7% for oil and 15.2% for coal. The natural gas share of worldwide energy consumption moved up from 20.1% in 1982 to 22.8% in 1992. The biggest change was in the C.I.S. and East Europe, where the gas share of total energy use rose from 28.8% in 1982 to 41.3% in 1992. In the OECD, the gas share of total energy use rose from 21.1% in 1982 to 21.5% in 1992. The natural gas industry was well-developed by 1982 in many industrial countries. In the developing world, gas provided 10.4% of total energy in 1982 and 12.5% in 1992. The paper discusses production trends, gas trade trends, natural gas prices, gas reserves, drilling shifts, and the demand outlook

DUV light source availability improvement via further enhancement of gas management technologies

Science.gov (United States)

Riggs, Daniel J.; O'Brien, Kevin; Brown, Daniel J. W.

2011-04-01

The continuous evolution of the semiconductor market necessitates ever-increasing improvements in DUV light source uptime as defined in the SEMI E10 standard. Cymer is developing technologies to exceed current and projected light source availability requirements via significant reduction in light source downtime. As an example, consider discharge chamber gas management functions which comprise a sizable portion of DUV light source downtime. Cymer's recent introduction of Gas Lifetime Extension (GLXTM) as a productivity improvement technology for its DUV lithography light sources has demonstrated noteworthy reduction in downtime. This has been achieved by reducing the frequency of full gas replenishment events from once per 100 million pulses to as low as once per 2 billion pulses. Cymer has continued to develop relevant technologies that target further reduction in downtime associated with light source gas management functions. Cymer's current subject is the development of technologies to reduce downtime associated with gas state optimization (e.g. total chamber gas pressure) and gas life duration. Current gas state optimization involves execution of a manual procedure at regular intervals throughout the lifetime of light source core components. Cymer aims to introduce a product enhancement - iGLXTM - that eliminates the need for the manual procedure and, further, achieves 4 billion pulse gas lives. Projections of uptime on DUV light sources indicate that downtime associated with gas management will be reduced by 70% when compared with GLX2. In addition to reducing downtime, iGLX reduces DUV light source cost of operation by constraining gas usage. Usage of fluorine rich Halogen gas mix has been reduced by 20% over GLX2.

Ballistic magnetotransport in a suspended two-dimensional electron gas with periodic antidot lattices

Energy Technology Data Exchange (ETDEWEB)

Zhdanov, E. Yu., E-mail: zhdanov@isp.nsc.ru; Pogosov, A. G.; Budantsev, M. V.; Pokhabov, D. A.; Bakarov, A. K. [Siberian Branch of the Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics (Russian Federation)

2017-01-15

The magnetoresistance of suspended semiconductor nanostructures with a two-dimensional electron gas structured by periodic square antidot lattices is studied. It is shown that the ballistic regime of electron transport is retained after detaching the sample from the substrate. Direct comparative analysis of commensurability oscillations of magnetoresistance and their temperature dependences in samples before and after suspension is performed. It is found that the temperature dependences are almost identical for non-suspended and suspended samples, whereas significant differences are observed in the nonlinear regime, caused by direct current passage. Commensurability oscillations in the suspended samples are more stable with respect to exposure to direct current, which can be presumably explained by electron–electron interaction enhancement after detaching nanostructures from the high-permittivity substrate.

High molecular gas fractions in normal massive star-forming galaxies in the young Universe.

Science.gov (United States)

Tacconi, L J; Genzel, R; Neri, R; Cox, P; Cooper, M C; Shapiro, K; Bolatto, A; Bouché, N; Bournaud, F; Burkert, A; Combes, F; Comerford, J; Davis, M; Schreiber, N M Förster; Garcia-Burillo, S; Gracia-Carpio, J; Lutz, D; Naab, T; Omont, A; Shapley, A; Sternberg, A; Weiner, B

2010-02-11

Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that young galaxies were much more molecular-gas rich. Molecular gas observations in the distant Universe have so far largely been restricted to very luminous, rare objects, including mergers and quasars, and accordingly we do not yet have a clear idea about the gas content of more normal (albeit massive) galaxies. Here we report the results of a survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3, when the Universe was respectively 40% and 24% of its current age. Our measurements reveal that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch. The average fraction of cold gas relative to total galaxy baryonic mass at z = 2.3 and z = 1.2 is respectively about 44% and 34%, three to ten times higher than in today's massive spiral galaxies. The slow decrease between z approximately 2 and z approximately 1 probably requires a mechanism of semi-continuous replenishment of fresh gas to the young galaxies.

Pluri annual indicative plan of the investments in the gas sector; Plan indicatif pluriannuel des investissements dans le secteur du gaz Periode 2006-2015

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-03-15

This indicative plan constitutes the first report to the Parliament. It is a prospective document for the period 2006-2015 containing: a forecast of the gas demand increase, a description of main investments decided in matter of gas infrastructures, a diagnostic concerning the adequation between the supplying capacities in natural gas and the national needs, a series of recommendations on the State tools to guarantee the national supplying security and on the investment. The four parts deal with the stakes and perspectives of the national natural gas supplying, the demand evolution, the offer evolution and the equilibrium offer. (A.L.B.)

DMRT1 Is Required for Mouse Spermatogonial Stem Cell Maintenance and Replenishment.

Science.gov (United States)

Zhang, Teng; Oatley, Jon; Bardwell, Vivian J; Zarkower, David

2016-09-01

Male mammals produce sperm for most of postnatal life and therefore require a robust germ line stem cell system, with precise balance between self-renewal and differentiation. Prior work established doublesex- and mab-3-related transcription factor 1 (Dmrt1) as a conserved transcriptional regulator of male sexual differentiation. Here we investigate the role of Dmrt1 in mouse spermatogonial stem cell (SSC) homeostasis. We find that Dmrt1 maintains SSCs during steady state spermatogenesis, where it regulates expression of Plzf, another transcription factor required for SSC maintenance. We also find that Dmrt1 is required for recovery of spermatogenesis after germ cell depletion. Committed progenitor cells expressing Ngn3 normally do not contribute to SSCs marked by the Id4-Gfp transgene, but do so when spermatogonia are chemically depleted using busulfan. Removal of Dmrt1 from Ngn3-positive germ cells blocks the replenishment of Id4-GFP-positive SSCs and recovery of spermatogenesis after busulfan treatment. Our data therefore reveal that Dmrt1 supports SSC maintenance in two ways: allowing SSCs to remain in the stem cell pool under normal conditions; and enabling progenitor cells to help restore the stem cell pool after germ cell depletion.

Optimality of cycle time and inventory decisions in a two echelon inventory system with exponential price dependent demand under credit period

Science.gov (United States)

Krugon, Seelam; Nagaraju, Dega

2017-05-01

This work describes and proposes an two echelon inventory system under supply chain, where the manufacturer offers credit period to the retailer with exponential price dependent demand. The model is framed as demand is expressed as exponential function of retailer’s unit selling price. Mathematical model is framed to demonstrate the optimality of cycle time, retailer replenishment quantity, number of shipments, and total relevant cost of the supply chain. The major objective of the paper is to provide trade credit concept from the manufacturer to the retailer with exponential price dependent demand. The retailer would like to delay the payments of the manufacturer. At the first stage retailer and manufacturer expressions are expressed with the functions of ordering cost, carrying cost, transportation cost. In second stage combining of the manufacturer and retailer expressions are expressed. A MATLAB program is written to derive the optimality of cycle time, retailer replenishment quantity, number of shipments, and total relevant cost of the supply chain. From the optimality criteria derived managerial insights can be made. From the research findings, it is evident that the total cost of the supply chain is decreased with the increase in credit period under exponential price dependent demand. To analyse the influence of the model parameters, parametric analysis is also done by taking with help of numerical example.

Optimal ordering quantities for substitutable deteriorating items under joint replenishment with cost of substitution

Science.gov (United States)

Mishra, Vinod Kumar

2017-09-01

In this paper we develop an inventory model, to determine the optimal ordering quantities, for a set of two substitutable deteriorating items. In this inventory model the inventory level of both items depleted due to demands and deterioration and when an item is out of stock, its demands are partially fulfilled by the other item and all unsatisfied demand is lost. Each substituted item incurs a cost of substitution and the demands and deterioration is considered to be deterministic and constant. Items are order jointly in each ordering cycle, to take the advantages of joint replenishment. The problem is formulated and a solution procedure is developed to determine the optimal ordering quantities that minimize the total inventory cost. We provide an extensive numerical and sensitivity analysis to illustrate the effect of different parameter on the model. The key observation on the basis of numerical analysis, there is substantial improvement in the optimal total cost of the inventory model with substitution over without substitution.

Steady Secondary Flows Generated by Periodic Compression and Expansion of an Ideal Gas in a Pulse Tube

Science.gov (United States)

Lee, Jeffrey M.

1999-01-01

This study establishes a consistent set of differential equations for use in describing the steady secondary flows generated by periodic compression and expansion of an ideal gas in pulse tubes. Also considered is heat transfer between the gas and the tube wall of finite thickness. A small-amplitude series expansion solution in the inverse Strouhal number is proposed for the two-dimensional axisymmetric mass, momentum and energy equations. The anelastic approach applies when shock and acoustic energies are small compared with the energy needed to compress and expand the gas. An analytic solution to the ordered series is obtained in the strong temperature limit where the zeroth-order temperature is constant. The solution shows steady velocities increase linearly for small Valensi number and can be of order I for large Valensi number. A conversion of steady work flow to heat flow occurs whenever temperature, velocity or phase angle gradients are present. Steady enthalpy flow is reduced by heat transfer and is scaled by the Prandtl times Valensi numbers. Particle velocities from a smoke-wire experiment were compared with predictions for the basic and orifice pulse tube configurations. The theory accurately predicted the observed steady streaming.

GAS AND COAL EXTRACTIVE INDUSTRY DURING THE SOCIALIST INDUSTRIALIZATION PERIOD (1948-1989

Directory of Open Access Journals (Sweden)

MARIUS BULEARCA

2015-12-01

Full Text Available This article shows that since 1949 the extractive industry has undergone a strong process of restructuring when enterprises were nationalized and a strict control over all components of the economy was established. The new leadership of the country had the intention of developing the industrial sector as well, basically laying the foundations of the new Romanian economy where the industrial sector economy would bring considerable income. This program will lead to the development of the energy sector in Romania also, thus contributing to a great extent to the development and consolidation of coal and gas extraction. Despite of all the economic and social development achieved during the period 1950-1989, at the end of it, Romania ranked a marginal position in the European countries hierarchy since between its level of development and the market economy developed countries large gaps in respect to the main economic and social indicators occurred.

Fire damp gas in a heavy water reactor; Praskavi gas u teskovodnom reaktoru

Energy Technology Data Exchange (ETDEWEB)

Nikolic, V D [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Yugoslavia)

1963-07-01

This document describes the process of fire damp gas creation in the reactor core and dependence of the gas percentage on the temperature, i.e. reactor power. It contains a detailed plan for measuring the the percent of fire damp gas at the RA reactor: before start-up, after longer shut-down periods, immediately after safety shutdown, periodically during operation campaign.

Three-dimensional modeling of the neutral gas depletion effect in a helicon discharge plasma

Science.gov (United States)

Kollasch, Jeffrey; Schmitz, Oliver; Norval, Ryan; Reiter, Detlev; Sovinec, Carl

2016-10-01

Helicon discharges provide an attractive radio-frequency driven regime for plasma, but neutral-particle dynamics present a challenge to extending performance. A neutral gas depletion effect occurs when neutrals in the plasma core are not replenished at a sufficient rate to sustain a higher plasma density. The Monte Carlo neutral particle tracking code EIRENE was setup for the MARIA helicon experiment at UW Madison to study its neutral particle dynamics. Prescribed plasma temperature and density profiles similar to those in the MARIA device are used in EIRENE to investigate the main causes of the neutral gas depletion effect. The most dominant plasma-neutral interactions are included so far, namely electron impact ionization of neutrals, charge exchange interactions of neutrals with plasma ions, and recycling at the wall. Parameter scans show how the neutral depletion effect depends on parameters such as Knudsen number, plasma density and temperature, and gas-surface interaction accommodation coefficients. Results are compared to similar analytic studies in the low Knudsen number limit. Plans to incorporate a similar Monte Carlo neutral model into a larger helicon modeling framework are discussed. This work is funded by the NSF CAREER Award PHY-1455210.

Distributions of crystals and gas bubbles in reservoir ice during growth period

Directory of Open Access Journals (Sweden)

Zhi-jun Li

2011-06-01

Full Text Available In order to understand the dominant factors of the physical properties of ice in ice thermodynamics and mechanics, in-situ observations of ice growth and decay processes were carried out. Two samplings were conducted in the fast and steady ice growth stages. Ice pieces were used to observe ice crystals and gas bubbles in ice, and to measure the ice density. Vertical profiles of the type and size of ice crystals, shape and size of gas bubbles, and gas bubble content, as well as the ice density, were obtained. The results show that the upper layer of the ice pieces is granular ice and the lower layer is columnar ice; the average crystal size increases with the ice depth and remains steady in the fast and steady ice growth stages; the shape of gas bubbles in the upper layer of ice pieces is spherical with higher total content, and the shape in the middle and lower layers is cylinder with lower total content; the gas bubble size and content vary with the ice growth stage; and the ice density decreases with the increase of the gas bubble content.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

TEA) CO2 laser was studied for different gas flow configurations. For an optimized gas flow configuration, repetitive operation was achieved at a much smaller gas replenishment factor between two successive pulses when compared with ...

Periodic motions and chaos for a damped mobile piston system in a high pressure gas cylinder with P control

International Nuclear Information System (INIS)

Wang, Donghua; Huang, Jianzhe

2017-01-01

In this paper, the complex motions for a moving piston in a closed gas cylinder will be analyzed using the discrete implicit maps method. The strong nonlinearity of such system will be observed due to the large quadratic and cubic stiffness. Period-1 motions which contain high order of harmonic components will be presented. The periodic motions will be discretized into multiple continuous mappings, and such mapping can be analyzed via Newton–Raphson iteration. The stability analysis will be given and the analytic conditions for the saddle-node and period-doubling bifurcation will be determined. From the semi-analytic solution route, the possible motions without considering the impact of the piston with the end wall of the cylinder will be obtained analytically. The scheme to reduce the vibration of the piston can be obtained through the parameter studies.

NAD+ Replenishment Improves Lifespan and Healthspan in Ataxia Telangiectasia Models via Mitophagy and DNA Repair.

Science.gov (United States)

Fang, Evandro Fei; Kassahun, Henok; Croteau, Deborah L; Scheibye-Knudsen, Morten; Marosi, Krisztina; Lu, Huiming; Shamanna, Raghavendra A; Kalyanasundaram, Sumana; Bollineni, Ravi Chand; Wilson, Mark A; Iser, Wendy B; Wollman, Bradley N; Morevati, Marya; Li, Jun; Kerr, Jesse S; Lu, Qiping; Waltz, Tyler B; Tian, Jane; Sinclair, David A; Mattson, Mark P; Nilsen, Hilde; Bohr, Vilhelm A

2016-10-11

Ataxia telangiectasia (A-T) is a rare autosomal recessive disease characterized by progressive neurodegeneration and cerebellar ataxia. A-T is causally linked to defects in ATM, a master regulator of the response to and repair of DNA double-strand breaks. The molecular basis of cerebellar atrophy and neurodegeneration in A-T patients is unclear. Here we report and examine the significance of increased PARylation, low NAD + , and mitochondrial dysfunction in ATM-deficient neurons, mice, and worms. Treatments that replenish intracellular NAD + reduce the severity of A-T neuropathology, normalize neuromuscular function, delay memory loss, and extend lifespan in both animal models. Mechanistically, treatments that increase intracellular NAD + also stimulate neuronal DNA repair and improve mitochondrial quality via mitophagy. This work links two major theories on aging, DNA damage accumulation, and mitochondrial dysfunction through nuclear DNA damage-induced nuclear-mitochondrial signaling, and demonstrates that they are important pathophysiological determinants in premature aging of A-T, pointing to therapeutic interventions. Published by Elsevier Inc.

Joint Decisions on Emission Reduction and Inventory Replenishment with Overconfidence and Low-Carbon Preference

Directory of Open Access Journals (Sweden)

Shoufeng Ji

2018-04-01

Full Text Available This paper presents a game-theoretical analysis of joint decisions on carbon emission reduction and inventory replenishment with overconfidence and consumer’s low-carbon preference for key supply chain players when facing effort-dependent demand. We consider respectively the overconfidence of a supplier who overestimates the impacts of his emission reduction efforts on product demand and the overconfidence of a retailer who underestimates the variability of the stochastic demand. We find, surprisingly, that the supplier’s overconfidence can mitigate “double marginalization” but hurt self-profit, while the retailer’s overconfidence can be an irrelevant factor for self-profit. The retailer aiming at short-term trading should actively seek an overconfident supplier, while the supplier should actively seek a rational retailer for whom the critical fractile is more than 0.5, whereas for an overconfident retailer, the critical fractile is less than or equal to 0.5. The study also underlines the effect of regulation parameters as an important contextual factor influencing low-carbon operations.

What justifies the lack of alignment between natural gas and crude oil prices in the period 2006-2007; O que justifica o deslocamento entre os precos do gas natural e do petroleo no periodo 2006-2007

Energy Technology Data Exchange (ETDEWEB)

Abreu, Ana Lucia Vahia de; Pinelli, Marcelo Santos

2008-07-01

The objective of the work is to show that the mismatch between Brent and Henry Hub in the period 2006-2007 is mainly due to the local characteristics of natural gas market. After the beginning of 2008, the price of Henry Hub is increasing and returning to the long term relationship (nonlinear) with Brent. Even with local features, the natural gas market tends to be a market of tradable goods. (author.

Mapping organelle motion reveals a vesicular conveyor belt spatially replenishing secretory vesicles in stimulated chromaffin cells.

Science.gov (United States)

Maucort, Guillaume; Kasula, Ravikiran; Papadopulos, Andreas; Nieminen, Timo A; Rubinsztein-Dunlop, Halina; Meunier, Frederic A

2014-01-01

How neurosecretory cells spatially adjust their secretory vesicle pools to replenish those that have fused and released their hormonal content is currently unknown. Here we designed a novel set of image analyses to map the probability of tracked organelles undergoing a specific type of movement (free, caged or directed). We then applied our analysis to time-lapse z-stack confocal imaging of secretory vesicles from bovine Chromaffin cells to map the global changes in vesicle motion and directionality occurring upon secretagogue stimulation. We report a defined region abutting the cortical actin network that actively transports secretory vesicles and is dissipated by actin and microtubule depolymerizing drugs. The directionality of this "conveyor belt" towards the cell surface is activated by stimulation. Actin and microtubule networks therefore cooperatively probe the microenvironment to transport secretory vesicles to the periphery, providing a mechanism whereby cells globally adjust their vesicle pools in response to secretagogue stimulation.

Computer simulation of multiple stability regions in an internally cooled superconducting conductor and of helium replenishment in a bath-cooled conductor

International Nuclear Information System (INIS)

Turner, L.R.; Shindler, J.

1984-09-01

For upcoming fusion experiments and future fusion reactors, superconducting magnetic have been chosen or considered which employ cooling by pool-boiling HeI, by HeII, and by internally flowing HeI. The choice of conductor and cooling method should be determined in part by the response of the magnet to sudden localized heat pulses of various magnitudes. The paper describes the successful computer simulation of multiple stability in internally cooled conductors, as observed experimentally, using the computer code SSICC. It also describes the modeling of helium replenishment in the cooling channels of a bath-cooled conductor, using the computer code TASS

Hydrates on tap: scientists say natural gas hydrates may be tough nut to crack

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.

2001-12-01

Gas hydrates are methane molecules trapped in cages of water molecules, yielding a substance with a slushy, sherbet-like consistency. Drilling for hydrates is similar to conventional oil and gas drilling, however, the secret to economic production still remains hidden. Hydrates exist in abundance in such places as deep ocean floor and below ground in some polar regions. The real challenge lies in producing gas from this resource, inasmuch as there is no existing technology for production of gas specifically from methane hydrates. This paper describes an international research program, involving a five-country partnership to spud the first of three wells into the permafrost of the Mackenzie River Delta in the Northwest Territories. The project, worth about $15 million, has brought together public funding and expertise from Japan, Germany, India as well as the Canadian and US Geological Surveys and the US Dept. of Energy in an effort to gain information on the production response of gas hydrates. The operator of the project is Japan Petroleum Exploration Company of Canada, a subsidiary of Japan National Oil Corporation. Since Japan is poor in domestic hydrocarbon resources, but is surrounded by deep water that contains potential for gas hydrates, Japan has a great deal riding on the success of this project. Germany and the United States are also very much interested. Current thinking is that gas is in contact with the hydrates and that it should be possible to develop a free gas reservoir as if it were a conventional deposit. As the free gas is drawn off, the pressure is reduced on the hydrates in contact with it , the hydrates dissociate from the gas and replenish the conventional reservoir. So far this is still only a theory, but it appears to be a sensible approach to hydrate production. 1 photo.

Assessment of Aquifer Age and Replenishment Rate by Utilizing 36Cl-Pulse

International Nuclear Information System (INIS)

Challan, M.B.; Challan, M.B.; Labib, A.A.; Labib, A.A.

2015-01-01

The present study aims at estimating the residence-time of groundwater based on bomb-produced 36 Cl. Water samples were collected from some selected wells located around Al-Zulfi province, Riyadh central region, Saudi Arabia. 36 The Cl/Cl ratios in the water samples were determined by Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Liquid Scintillation Counting(LSC). 36 The Cl/Cl ratios in the groundwater were estimated to be 1.0-2.0×10 -10 . The shallow unconfined aquifer of the area is mainly replenished by the water infiltration from the seasonal rains. Estimates of residence time were obtained by comparing the measured bomb-derived 36 Cl concentrations in groundwater with the background reference. Dating based on a 36 Cl bomb pulse may be more reliable and sensitive for groundwater recharged before 1975, back as far as the mid-1950s.The above 36 Cl-background concentration was deduced by determining accurately the background corrected Dye-3 ice core data from the frozen Arctic Data, according to the estimated total 3 '6Cl resources, including bomb-produced '3 6 Cl fallout. An estimated residence time of 7.81×10 4 y was obtained from extrapolated flow velocity. It was noticed that 36 Cl concentration in groundwater does not reflect the input of bomb pulse 36 Cl, it belongs to the era before 1950

Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice

Energy Technology Data Exchange (ETDEWEB)

Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Siegert, Christoph; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

2013-12-04

We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background.

Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice

International Nuclear Information System (INIS)

Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam; Siegert, Christoph; Farrer, Ian; Ritchie, David A.; Pepper, Michael

2013-01-01

We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background

Means and method for controlling the neutron output of a neutron generator tube

International Nuclear Information System (INIS)

Langford, O.M.; Peelman, H.E.

1980-01-01

A gas filled neutron tube in a nuclear well logging tool has a target an ion source voltage and a replenisher connected to ground. A negative high voltage is applied to the target by a power supply also providing a target current corresponding to the neutron output of the neutron generator tube. A constant current source provides a constant current. A network receiving the target current and the constant current provides a portion of the constant current as a replenisher current which is applied to the replenisher in a neutron generating tube. The network controls the magnitude of the replenisher current in accordance with the target current so as to control the neutron output of the neutron generating tube. (auth)

Assessment of offshore New Jersey sources of Beach replenishment sand by diversified application of geologic and geophysical methods

Science.gov (United States)

Waldner, J.S.; Hall, D.W.; Uptegrove, J.; Sheridan, R.E.; Ashley, G.M.; Esker, D.

1999-01-01

Beach replenishment serves the dual purpose of maintaining a source of tourism and recreation while protecting life and property. For New Jersey, sources for beach sand supply are increasingly found offshore. To meet present and future needs, geologic and geophysical techniques can be used to improve the identification, volume estimation, and determination of suitability, thereby making the mining and managing of this resource more effective. Current research has improved both data collection and interpretation of seismic surveys and vibracore analysis for projects investigating sand ridges offshore of New Jersey. The New Jersey Geological Survey in cooperation with Rutgers University is evaluating the capabilities of digital seismic data (in addition to analog data) to analyze sand ridges. The printing density of analog systems limits the dynamic range to about 24 dB. Digital acquisition systems with dynamic ranges above 100 dB can permit enhanced seismic profiles by trace static correction, deconvolution, automatic gain scaling, horizontal stacking and digital filtering. Problems common to analog data, such as wave-motion effects of surface sources, water-bottom reverberation, and bubble-pulse-width can be addressed by processing. More than 160 line miles of digital high-resolution continuous profiling seismic data have been collected at sand ridges off Avalon, Beach Haven, and Barnegat Inlet. Digital multichannel data collection has recently been employed to map sand resources within the Port of New York/New Jersey expanded dredge-spoil site located 3 mi offshore of Sandy Hook, New Jersey. Multichannel data processing can reduce multiples, improve signal-to-noise calculations, enable source deconvolution, and generate sediment acoustic velocities and acoustic impedance analysis. Synthetic seismograms based on empirical relationships among grain size distribution, density, and velocity from vibracores are used to calculate proxy values for density and velocity

The effect of motivation and positive affect on ego depletion: Replenishment versus release mechanism.

Science.gov (United States)

Zhu, Ze; Li, Jian; Zhang, Bo; Li, Ye; Zhang, Houcan

2017-12-01

In this study, 2 experiments were conducted to investigate whether motivation and positive affect can alleviate ego depletion and to elucidate their possible mechanisms. In Experiment 1, a crossing-out-letter task was adapted to reach an ego depletion state for Chinese participants. Participants were then randomly assigned to the extrinsic motivation group, the positive affect group or the depletion control group. After the experimental treatment, a dumbbell task was used to measure participants' remaining self-regulatory resources. The results showed that participants in the motivation and positive affect groups performed better on the dumbbell task than participants in the depletion control group. Experiment 2 was similar to Experiment 1 except that participants were asked to perform an additional unexpected dumbbell task after a neutral video following the above procedure. The results of Experiment 1 were replicated; however, participants' performance on the additional dumbbell task differed. The positive affect group performed better than the depletion control group, indicating an increase in self-regulatory resources and thus supporting the replenishment effect of positive affect. No significant difference was found between the motivation group and the depletion control group. © 2015 International Union of Psychological Science.

Agricultural demands for natural gas and liquified petroleum gas in the USA

International Nuclear Information System (INIS)

Uri, N.D.; Gill, M.

1992-01-01

This study endeavours to determine whether farmers adjust their consumption of natural gas and liquefied petroleum gas in response to changes in the unit price of energy. A demand model is specified and estimated. The conclusions suggest that the unit price of natural gas (liquefied petroleum gas) is a factor impacting the quantity of natural gas (liquefied petroleum gas) demanded by farmers, but there is no indication that other types of energy are substitutes for natural gas or liquefied petroleum gas. Additionally, the number of acres irrigated is an important factor driving the demand for natural gas and liquefied petroleum gas. Finally, the estimated models of natural gas and liquefied petroleum gas demand were structurally stable over the period 1971-1989. (author)

Device for purifying exhaust gas

International Nuclear Information System (INIS)

Makita, Kiyoshi.

1973-01-01

Purpose: To ensure the reliability in collection of krypton even on accident in liquidizing distillation tower. Constitution: Exhaust gas flows through active carbon adsorption tower where short half-life rare gas in exhaust gas is separated by adsorption, then through heat exchanger, then continuous distillation tower where krypton 85 is separated, then through batch distillation tower where krypton 85 is condensed, and then flows into storing cylinder. On accident in liquidizing distillation tower, at the first period exhaust gas flows through series connected active carbon adsorption tower, krypton 85 adsorbed in adsorption tower being transferred to cooling type adsorption tower, at the next period exhaust gas flows through tower, krypton 85 adsorbed in adsorption tower being transferred to tower. (M. K.)

X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

International Nuclear Information System (INIS)

McLeod, K.; Kumar, S.; Dutta, N.K.; Smart, R.St.C.; Voelcker, N.H.; Anderson, G.I.

2010-01-01

Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 μm in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

Energy Technology Data Exchange (ETDEWEB)

McLeod, K. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Kumar, S., E-mail: sunil.kumar@unisa.edu.au [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Dutta, N.K. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Smart, R.St.C. [Applied Centre for Structural and Synchrotron Studies, University of South Australia, Mawson Lakes, SA 5095 (Australia); Voelcker, N.H. [School of Chemistry, Physics and Earth Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide 5001 (Australia); Anderson, G.I. [School of Veterinary Science, University of Adelaide, Adelaide, SA 5005 (Australia)

2010-09-15

Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 {mu}m in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

Novel characterization of monocyte-derived cell populations in the meninges and choroid plexus and their rates of replenishment in bone marrow chimeric mice.

Science.gov (United States)

Chinnery, Holly R; Ruitenberg, Marc J; McMenamin, Paul G

2010-09-01

The mouse dura mater, pia mater, and choroid plexus contain resident macrophages and dendritic cells (DCs). These cells participate in immune surveillance, phagocytosis of cellular debris, uptake of antigens from the surrounding cerebrospinal fluid and immune regulation in many pathologic processes. We used Cx3cr1 knock-in, CD11c-eYFP transgenic and bone marrow chimeric mice to characterize the phenotype, density and replenishment rate of monocyte-derived cells in the meninges and choroid plexus and to assess the role of the chemokine receptor CX3CR1 on their number and tissue distribution. Iba-1 major histocompatibility complex (MHC) Class II CD169 CD68 macrophages and CD11c putative DCs were identified in meningeal and choroid plexus whole mounts. Comparison of homozygous and heterozygous Cx3cr1 mice did not reveal CX3CR1-dependancy on density, distribution or phenotype of monocyte-derived cells. In turnover studies, wild type lethally irradiated mice were reconstituted with Cx3cr1/-positive bone marrow and were analyzed at 3 days, 1, 2, 4 and 8 weeks after transplantation. There was a rapid replenishment of CX3CR1-positive cells in the dura mater (at 4 weeks) and the choroid plexus was fully reconstituted by 8 weeks. These data provide the foundation for future studies on the role of resident macrophages and DCs in conditions such as meningitis, autoimmune inflammatory disease and in therapies involving irradiation and hematopoietic or stem cell transplantation.

Compilation of gas geochemistry and isotopic analyses from The Geysers geothermal field: 1978-1991

Science.gov (United States)

Lowenstern, Jacob B.; Janik, Cathy; Fahlquist, Lynne; Johnson, Linda S.

1999-01-01

We present 45 chemical and isotopic analyses from well discharges at The Geysers geothermal field and summarize the most notable geochemical trends. H2 and H2S concentrations are highest in the Southeast Geysers, where steam samples have δD and δ18O values that reflect replenishment by meteoric water. In the Northwest Geysers, samples are enriched in gas/steam, CO2, CH4, and N2/Ar relative to the rest of the field, and contain steam that is elevated in δD and δ18O, most likely due to substantial contributions from Franciscan-derived fluids. The δ13C of CO2, trends in CH4 vs. N2, and abundance of NH3 indicate that the bulk of the non-condensable gases are derived from thermal breakdown of organic materials in Franciscan meta-sediments.

Characteristic Value Method of Well Test Analysis for Horizontal Gas Well

Directory of Open Access Journals (Sweden)

Xiao-Ping Li

2014-01-01

Full Text Available This paper presents a study of characteristic value method of well test analysis for horizontal gas well. Owing to the complicated seepage flow mechanism in horizontal gas well and the difficulty in the analysis of transient pressure test data, this paper establishes the mathematical models of well test analysis for horizontal gas well with different inner and outer boundary conditions. On the basis of obtaining the solutions of the mathematical models, several type curves are plotted with Stehfest inversion algorithm. For gas reservoir with closed outer boundary in vertical direction and infinite outer boundary in horizontal direction, while considering the effect of wellbore storage and skin effect, the pseudopressure behavior of the horizontal gas well can manifest four characteristic periods: pure wellbore storage period, early vertical radial flow period, early linear flow period, and late horizontal pseudoradial flow period. For gas reservoir with closed outer boundary both in vertical and horizontal directions, the pseudopressure behavior of the horizontal gas well adds the pseudosteady state flow period which appears after the boundary response. For gas reservoir with closed outer boundary in vertical direction and constant pressure outer boundary in horizontal direction, the pseudopressure behavior of the horizontal gas well adds the steady state flow period which appears after the boundary response. According to the characteristic lines which are manifested by pseudopressure derivative curve of each flow period, formulas are developed to obtain horizontal permeability, vertical permeability, skin factor, reservoir pressure, and pore volume of the gas reservoir, and thus the characteristic value method of well test analysis for horizontal gas well is established. Finally, the example study verifies that the new method is reliable. Characteristic value method of well test analysis for horizontal gas well makes the well test analysis

Greenhouse gas emissions from shale gas and coal for electricity generation in South Africa

Directory of Open Access Journals (Sweden)

Brett Cohen

2014-03-01

Full Text Available There is increased interest, both in South Africa and globally, in the use of shale gas for electricity and energy supply. The exploitation of shale gas is, however, not without controversy, because of the reported environmental impacts associated with its extraction. The focus of this article is on the greenhouse gas footprint of shale gas, which some literature suggests may be higher than what would have been expected as a consequence of the contribution of fugitive emissions during extraction, processing and transport. Based on some studies, it has been suggested that life-cycle emissions may be higher than those from coal-fired power. Here we review a number of studies and analyse the data to provide a view of the likely greenhouse gas emissions from producing electricity from shale gas, and compare these emissions to those of coal-fired power in South Africa. Consideration was given to critical assumptions that determine the relative performance of the two sources of feedstock for generating electricity � that is the global warming potential of methane and the extent of fugitive emissions. The present analysis suggests that a 100-year time horizon is appropriate in analysis related to climate change, over which period the relative contribution is lower than for shorter periods. The purpose is to limit temperature increase in the long term and the choice of metric should be appropriate. The analysis indicates that, regardless of the assumptions about fugitive emissions and the period over which global warming potential is assessed, shale gas has lower greenhouse gas emissions per MWh of electricity generated than coal. Depending on various factors, electricity from shale gas would have a specific emissions intensity between 0.3 tCO2/MWh and 0.6 tCO2/MWh, compared with about 1 tCO2/MWh for coal-fired electricity in South Africa.

Periodic DFT study of acidic trace atmospheric gas molecule adsorption on Ca- and Fe-doped MgO(001) surface basic sites.

Science.gov (United States)

Baltrusaitis, Jonas; Hatch, Courtney; Orlando, Roberto

2012-08-02

The electronic properties of undoped and Ca- or Fe-doped MgO(001) surfaces, as well as their propensity toward atmospheric acidic gas (CO2, SO2, and NO2) uptake was investigated with an emphasis on gas adsorption on the basic MgO oxygen surface sites, O(surf), using periodic density functional theory (DFT) calculations. Adsorption energy calculations show that MgO doping will provide stronger interactions of the adsorbate with the O(surf) sites than the undoped MgO for a given adsorbate molecule. Charge transfer from the iron atom in Fe-doped MgO(001) to NO2 was shown to increase the binding interaction between adsorbate by an order of magnitude, when compared to that of undoped and Ca-doped MgO(001) surfaces. Secondary binding interactions of adsorbate oxygen atoms were observed with surface magnesium sites at distances close to those of the Mg-O bond within the crystal. These interactions may serve as a preliminary step for adsorption and facilitate further adsorbate transformations into other binding configurations. Impacts on global atmospheric chemistry are discussed as these adsorption phenomena can affect atmospheric gas budgets via altered partitioning and retention on mineral aerosol surfaces.

Semi-annual report for the unconventional gas recovery program, period ending September 30, 1980

Energy Technology Data Exchange (ETDEWEB)

Manilla, R.D. (ed.)

1980-11-01

Progress is reported in research on methane recovery from coalbeds, eastern gas shales, western gas sands, and geopressured aquifers. In the methane from coalbeds project, data on information evaluation and management, resource and site assessment and characterization, model development, instrumentation, basic research, and production technology development are reported. In the methane from eastern gas shales project, data on resource characterization and inventory, extraction technology, and technology testing and verification are presented. In the western gas sands project, data on resource assessments, field tests and demonstrations and project management are reported. In the methane from geopressured aquifers project, data on resource assessment, supporting research, field tests and demonstrations, and technology transfer are reported.

INFORMATION FOR GAS USERS

CERN Multimedia

Logistics Group

2001-01-01

The contractor for the supply and distribution of pressurised gases has drawn our attention to the large number of gas bottles and banks being stored on the site for increasingly long periods. Users are reminded that the rental charges for gas bottles and banks are based on a progressive rate depending on their period of use. To assist CERN in its efforts to optimise its operations in this field, you are kindly requested : to return empty or unused containers to the official gas distribution points as soon as possible, to try to limit reserve stocks, bearing in mind that standardised gases can be delivered within 36 hours. This will result in a higher turnover rate and in increased safety and will improve the availability of the gases. For all further enquiries, please contact Gas.Store@cern.ch by e-mail or call 72265. Thank you for your co-operation.

Information for gas users

CERN Multimedia

2003-01-01

The contractor for the supply and distribution of pressurised gases has drawn our attention to the large number of gas bottles and banks being stored on the site for increasingly long periods. Users are reminded that the rental charges for gas bottles and banks are based on a progressive rate depending on their period of use. To assist CERN in its efforts to optimise its operations in this field, you are kindly requested: - to return empty or unused containers to the official gas distribution points as soon as possible - to try to limit reserve stocks, bearing in mind that standardised gases can be delivered within 36 hours. This will result in a higher turnover rate and in increased safety and will improve the availability of the gases. For all further enquiries, please contact "Gas store" by e-mail. Thank you for your co-operation. Logistics Group SPL Division

Natural gas - Grows the interest for its search

International Nuclear Information System (INIS)

Carta Petrolera

1998-01-01

The Colombian Government, through ECOPETROL, modified some clauses in the association contracts, like they are incentives in the search and exploitation of deposits of natural gas, in such a way that several oil companies are guiding his exploration toward the gas; these new game rules are applied for discoveries of gas, like in those discoveries of petroleum and gas. The period of exploitation is enlarged and the period of exploration is enlarged in inactive areas, among other changes

The General Adaptation Syndrome: A Foundation for the Concept of Periodization.

Science.gov (United States)

Cunanan, Aaron J; DeWeese, Brad H; Wagle, John P; Carroll, Kevin M; Sausaman, Robert; Hornsby, W Guy; Haff, G Gregory; Triplett, N Travis; Pierce, Kyle C; Stone, Michael H

2018-04-01

Recent reviews have attempted to refute the efficacy of applying Selye's general adaptation syndrome (GAS) as a conceptual framework for the training process. Furthermore, the criticisms involved are regularly used as the basis for arguments against the periodization of training. However, these perspectives fail to consider the entirety of Selye's work, the evolution of his model, and the broad applications he proposed. While it is reasonable to critically evaluate any paradigm, critics of the GAS have yet to dismantle the link between stress and adaptation. Disturbance to the state of an organism is the driving force for biological adaptation, which is the central thesis of the GAS model and the primary basis for its application to the athlete's training process. Despite its imprecisions, the GAS has proven to be an instructive framework for understanding the mechanistic process of providing a training stimulus to induce specific adaptations that result in functional enhancements. Pioneers of modern periodization have used the GAS as a framework for the management of stress and fatigue to direct adaptation during sports training. Updates to the periodization concept have retained its founding constructs while explicitly calling for scientifically based, evidence-driven practice suited to the individual. Thus, the purpose of this review is to provide greater clarity on how the GAS serves as an appropriate mechanistic model to conceptualize the periodization of training.

Compositional simulations of producing oil-gas ratio behaviour in low permeable gas condensate reservoir

OpenAIRE

Gundersen, Pål Lee

2013-01-01

Master's thesis in Petroleum engineering Gas condensate flow behaviour below the dew point in low permeable formations can make accurate fluid sampling a difficult challenge. The objective of this study was to investigate the producing oil-gas ratio behaviour in the infinite-acting period for a low permeable gas condensate reservoir. Compositional isothermal flow simulations were performed using a single-layer, radial and two-dimensional, gas condensate reservoir model with low permeabili...

Monitoring gas quality green gas feeding in; Monitoring gaskwaliteit groengasinvoeding

Energy Technology Data Exchange (ETDEWEB)

Holstein, J. [DNV KEMA Energy and Sustainability, Arnhem (Netherlands); Polman, E. [Kiwa Technology, Apeldoorn (Netherlands)

2013-04-15

Due to the growing number of green gas facilities in the Netherlands more practical knowledge is collected about the production and injection of green gas. Also there was the need to gather data about more practical experiences and knowledge about the gas quality, the performance of gas cleaning and gas treatment systems, as well the integration of green gas in the gas infrastructure. In addition to this, there is a need to get insight in the safety aspects of green gas injection. In order to comply this demand, DNV KEMA en Kiwa Technology measured the quality parameters continuously between June 2012 en January 2013 (three weeks) and discontinuously (gas samples) of green gas at eight production facilities. The measurements have been performed at designated places and are independent from the measurements of the biomethane producer. In order to be sure that the results of DNV KEMA and Kiwa are comparable, a combined measurement program was executed. It results in uniformity for all the measured values: the differences are within the uncertainty level for each component. During the measurement period of three weeks, the gas quality parameters were compared to specifications, written down in the national regulations for the transport and the distribution grid respectively [Dutch] Door het groeiend aantal groengasinvoedingen in Nederland wordt steeds meer praktijkkennis verzameld. Er dient meer praktijkkennis te worden verzameld over de chemische gaskwaliteit, prestaties van de gasreiniging- en gasopwaardering en de wijze van inpassing in de bestaande infrastructuur. Daarnaast is het wenselijk om inzicht te verkrijgen in de veiligheid van groengasinvoeding. Daarop is de groengaskwaliteit op acht locaties over een periode van drie weken continu en discontinu gemeten tussen juni 2012 en januari 2013. De metingen zijn uitgevoerd op een aangewezen plaats door de netbeheerder en staan los van de metingen van de invoeders zelf. Voor het waarborgen van de uniformiteit van

Optimising multi-product multi-chance-constraint inventory control system with stochastic period lengths and total discount under fuzzy purchasing price and holding costs

Science.gov (United States)

Allah Taleizadeh, Ata; Niaki, Seyed Taghi Akhavan; Aryanezhad, Mir-Bahador

2010-10-01

While the usual assumptions in multi-periodic inventory control problems are that the orders are placed at the beginning of each period (periodic review) or depending on the inventory level they can happen at any time (continuous review), in this article, we relax these assumptions and assume that the periods between two replenishments of the products are independent and identically distributed random variables. Furthermore, assuming that the purchasing price are triangular fuzzy variables, the quantities of the orders are of integer-type and that there are space and service level constraints, total discount are considered to purchase products and a combination of back-order and lost-sales are taken into account for the shortages. We show that the model of this problem is a fuzzy mixed-integer nonlinear programming type and in order to solve it, a hybrid meta-heuristic intelligent algorithm is proposed. At the end, a numerical example is given to demonstrate the applicability of the proposed methodology and to compare its performance with one of the existing algorithms in real world inventory control problems.

The Q(s,S) control policy for the joint replenishment problem extended to the case of correlation among item-demands

DEFF Research Database (Denmark)

Larsen, Christian

  We develop an algorithm to compute an optimal Q(s,S) policy for the joint replenishment problem when demands follow a compound correlated Poisson process. It is a non-trivial generalization of the work by Nielsen and Larsen (2005). We make some numerical analyses on two-item problems where we...... compare the optimal Q(s,S) policy to the optimal uncoordinated (s,S) policies. The results indicate that the more negative the correlation the less advantageous it is to coordinate. Therefore, in some cases the degree of correlation determines whether to apply the coordinated Q(s,S) policy...... or the uncoordinated (s,S) policies. Finally, we compare the Q(s,S) policy and the closely connected P(s,S) policy. Here we explain why the Q(s,S) policy is a better choice if item-demands are correlated....

Feasibility of flare gas reformation to practical energy in Farashband gas refinery: no gas flaring.

Science.gov (United States)

Rahimpour, Mohammad Reaza; Jokar, Seyyed Mohammad

2012-03-30

A suggested method for controlling the level of hazardous materials in the atmosphere is prevention of combustion in flare. In this work, three methods are proposed to recover flare gas instead of conventional gas-burning in flare at the Farashband gas refinery. These methods aim to minimize environmental and economical disadvantages of burning flare gas. The proposed methods are: (1) gas to liquid (GTL) production, (2) electricity generation with a gas turbine and, (3) compression and injection into the refinery pipelines. To find the most suitable method, the refinery units that send gas to the flare as well as the required equipment for the three aforementioned methods are simulated. These simulations determine the amount of flare gas, the number of GTL barrels, the power generated by the gas turbine and the required compression horsepower. The results of simulation show that 563 barrels/day of valuable GTL products is produced by the first method. The second method provides 25 MW electricity and the third method provides a compressed natural gas with 129 bar pressure for injection to the refinery pipelines. In addition, the economics of flare gas recovery methods are studied and compared. The results show that for the 4.176MMSCFD of gas flared from the Farashband gas refinery, the electricity production gives the highest rate of return (ROR), the lowest payback period, the highest annual profit and mild capital investment. Therefore, the electricity production is the superior method economically. Copyright © 2012 Elsevier B.V. All rights reserved.

Forming gas treatment of lithium ion battery anode graphite powders

Science.gov (United States)

Contescu, Cristian Ion; Gallego, Nidia C; Howe, Jane Y; Meyer, III, Harry M; Payzant, Edward Andrew; Wood, III, David L; Yoon, Sang Young

2014-09-16

The invention provides a method of making a battery anode in which a quantity of graphite powder is provided. The temperature of the graphite powder is raised from a starting temperature to a first temperature between 1000 and 2000.degree. C. during a first heating period. The graphite powder is then cooled to a final temperature during a cool down period. The graphite powder is contacted with a forming gas during at least one of the first heating period and the cool down period. The forming gas includes H.sub.2 and an inert gas.

Panorama 2010: Short-term trends in the gas industry

International Nuclear Information System (INIS)

Lecarpentier, A.

2010-01-01

After a period of strong expansion that lasted for most of 2008, the gas industry was hard hit by the impact of the economic recession. Although the competitiveness of the gas price was often an advantage in 2009, the natural gas market saw a net decline in consumption that led to a historic decrease in world production and international trade. In addition, the subsequent collapse of market prices gave LNG a competitive edge in the Atlantic Basin, where surplus gas continued to accumulate, heralding a long 'gas bubble' period that the industry will have to adjust to permit harmonious, long-term development of the gas markets. (author)

Role of stranded gas in increasing global gas supplies

Science.gov (United States)

Attanasi, E.D.; Freeman, P.A.

2013-01-01

This report synthesizes the findings of three regional studies in order to evaluate, at the global scale, the contribution that stranded gas resources can make to global natural gas supplies. Stranded gas, as defined for this study, is natural gas in discovered conventional gas and oil fields that is currently not commercially producible for either physical or economic reasons. The regional studies evaluated the cost of bringing the large volumes of undeveloped gas in stranded gas fields to selected markets. In particular, stranded gas fields of selected Atlantic Basin countries, north Africa, Russia, and central Asia are screened to determine whether the volumes are sufficient to meet Europe’s increasing demand for gas imports. Stranded gas fields in Russia, central Asia, Southeast Asia, and Australia are also screened to estimate development, production, and transport costs and corresponding gas volumes that could be supplied to Asian markets in China, India, Japan, and South Korea. The data and cost analysis presented here suggest that for the European market and the markets examined in Asia, the development of stranded gas provides a way to meet projected gas import demands for the 2020-to-2040 period. Although this is a reconnaissance-type appraisal, it is based on volumes of gas that are associated with individual identified fields. Individual field data were carefully examined. Some fields were not evaluated because current technology was insufficient or it appeared the gas was likely to be held off the export market. Most of the evaluated stranded gas can be produced and delivered to markets at costs comparable to historical prices. Moreover, the associated volumes of gas are sufficient to provide an interim supply while additional technologies are developed to unlock gas diffused in shale and hydrates or while countries transition to making a greater use of renewable energy sources.

Drought-induced defoliation and long periods of near-zero gas exchange play a key role in accentuating metabolic decline of Scots pine.

Science.gov (United States)

Poyatos, Rafael; Aguadé, David; Galiano, Lucía; Mencuccini, Maurizio; Martínez-Vilalta, Jordi

2013-10-01

Drought-induced defoliation has recently been associated with the depletion of carbon reserves and increased mortality risk in Scots pine (Pinus sylvestris). We hypothesize that defoliated individuals are more sensitive to drought, implying that potentially higher gas exchange (per unit of leaf area) during wet periods may not compensate for their reduced photosynthetic area. We measured sap flow, needle water potentials and whole-tree hydraulic conductance to analyse the drought responses of co-occurring defoliated and nondefoliated Scots pines in northeast Spain during typical (2010) and extreme (2011) drought conditions. Defoliated Scots pines showed higher sap flow per unit leaf area during spring, but were more sensitive to summer drought, relative to nondefoliated pines. This pattern was associated with a steeper decline in soil-to-leaf hydraulic conductance with drought and an enhanced sensitivity of canopy conductance to soil water availability. Near-homeostasis in midday water potentials was observed across years and defoliation classes, with minimum values of -2.5 MPa. Enhanced sensitivity to drought and prolonged periods of near-zero gas exchange were consistent with low levels of carbohydrate reserves in defoliated trees. Our results support the critical links between defoliation, water and carbon availability, and their key roles in determining tree survival and recovery under drought. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Neutron accelerator tube having improved ionization section

International Nuclear Information System (INIS)

Givens, W.W.

1982-01-01

A neutron accelerator tube is described having a target section, an ionization section, and a replenisher section for supplying accelerator gas to the ionization section. The ionization section is located between the target and the replenisher section and includes an ionization chamber adapted to receive accelerator gas from the replenisher section. The ionization section further includes spaced cathodes having opposed active surfaces exposed to the interior of the ionization chamber. An anode is located intermediate the cathodes whereby in response to an applied positive voltage, electrons created by field emission are transmitted between the opposed active surfaces of the cathodes and produce the emission of secondary electrons. The active surface of at least one of the cathodes is formulated of a material having a secondary electron emission factor of at least one cathode member located in the tube adjacent to th replenisher section may have a protuberant portion extending axially into the ionization chamber. The other cathode spaced from the first cathode member in the direction of the target has an aperture therein along the axis of the protuberant portion. An annular magnet extends around the exterior of the ionization chamber and envelops the anode member. Means are provided to establish a high permeability magnetic flux path extending outwardly from the opposed poles from the magnet to the active surfaces of the cathode members

Neutron accelerator tube having improved ionization section

International Nuclear Information System (INIS)

Givens, W.W.

1981-01-01

A neutron accelerator tube having a target section, an ionization section, and a replenisher section for supplying accelerator gas to the ionization section. The ionization section is located between the target and the replenisher section and includes an ionization chamber adapted to receive accelerator gas from the replenisher section. The ionization section further includes spaced cathodes having opposed active surfaces exposed to the interior of the ionization chamber. An anode is located intermediate the cathodes whereby in response to an applied positive voltage, electrons created by field emmission are transmitted between the opposed active surfaces of the cathodes and produce the emission of secondary electrons. The active surface of at least one of the cathodes is formulated of a material having a secondary electron emission factor of at least 2. One cathode member located in the tube adjacent to the replenisher section may have a protuberant portion extending axially into the ioization chamber. The other cathode spaced from the first cathode member in the direction of the target has an aperture therein along the axis of the protuberant portion. An annular magnet extends around the exterior of the ionization chamber and envelops the anode member. Means are provided to establish a high permeability magnetic flux path extending outwardly from the opposed poles from the magnet to the active surfaces of the cathode members

Improved methodology to assess modification and completion of landfill gas management in the aftercare period

International Nuclear Information System (INIS)

Morris, Jeremy W.F.; Crest, Marion; Barlaz, Morton A.; Spokas, Kurt A.; Åkerman, Anna; Yuan, Lei

2012-01-01

Highlights: ► Performance-based evaluation of landfill gas control system. ► Analytical framework to evaluate transition from active to passive gas control. ► Focus on cover oxidation as an alternative means of passive gas control. ► Integrates research on long-term landfill behavior with practical guidance. - Abstract: Municipal solid waste landfills represent the dominant option for waste disposal in many parts of the world. While some countries have greatly reduced their reliance on landfills, there remain thousands of landfills that require aftercare. The development of cost-effective strategies for landfill aftercare is in society’s interest to protect human health and the environment and to prevent the emergence of landfills with exhausted aftercare funding. The Evaluation of Post-Closure Care (EPCC) methodology is a performance-based approach in which landfill performance is assessed in four modules including leachate, gas, groundwater, and final cover. In the methodology, the objective is to evaluate landfill performance to determine when aftercare monitoring and maintenance can be reduced or possibly eliminated. This study presents an improved gas module for the methodology. While the original version of the module focused narrowly on regulatory requirements for control of methane migration, the improved gas module also considers best available control technology for landfill gas in terms of greenhouse gas emissions, air quality, and emissions of odoriferous compounds. The improved module emphasizes the reduction or elimination of fugitive methane by considering the methane oxidation capacity of the cover system. The module also allows for the installation of biologically active covers or other features designed to enhance methane oxidation. A methane emissions model, CALMIM, was used to assist with an assessment of the methane oxidation capacity of landfill covers.

Improved methodology to assess modification and completion of landfill gas management in the aftercare period

Energy Technology Data Exchange (ETDEWEB)

Morris, Jeremy W.F., E-mail: jmorris@geosyntec.com [Geosyntec Consultants, 10220 Old Columbia Road, Suite A, Columbia, MD 21046 (United States); Crest, Marion, E-mail: marion.crest@suez-env.com [Suez Environnement, 38 rue du President Wilson, 78230 Le Pecq (France); Barlaz, Morton A., E-mail: barlaz@ncsu.edu [Department of Civil, Construction, and Environmental Engineering, Campus Box 7908, North Carolina State University, Raleigh, NC 27695-7908 (United States); Spokas, Kurt A., E-mail: kurt.spokas@ars.usda.gov [United States Department of Agriculture - Agricultural Research Service, 1991 Upper Buford Circle, 439 Borlaug Hall, St. Paul, MN 55108 (United States); Akerman, Anna, E-mail: anna.akerman@sita.fr [SITA France, Tour CB 21, 16 Place de l' Iris, 92040 Paris La Defense Cedex (France); Yuan, Lei, E-mail: lyuan@geosyntec.com [Geosyntec Consultants, 10220 Old Columbia Road, Suite A, Columbia, MD 21046 (United States)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Performance-based evaluation of landfill gas control system. Black-Right-Pointing-Pointer Analytical framework to evaluate transition from active to passive gas control. Black-Right-Pointing-Pointer Focus on cover oxidation as an alternative means of passive gas control. Black-Right-Pointing-Pointer Integrates research on long-term landfill behavior with practical guidance. - Abstract: Municipal solid waste landfills represent the dominant option for waste disposal in many parts of the world. While some countries have greatly reduced their reliance on landfills, there remain thousands of landfills that require aftercare. The development of cost-effective strategies for landfill aftercare is in society's interest to protect human health and the environment and to prevent the emergence of landfills with exhausted aftercare funding. The Evaluation of Post-Closure Care (EPCC) methodology is a performance-based approach in which landfill performance is assessed in four modules including leachate, gas, groundwater, and final cover. In the methodology, the objective is to evaluate landfill performance to determine when aftercare monitoring and maintenance can be reduced or possibly eliminated. This study presents an improved gas module for the methodology. While the original version of the module focused narrowly on regulatory requirements for control of methane migration, the improved gas module also considers best available control technology for landfill gas in terms of greenhouse gas emissions, air quality, and emissions of odoriferous compounds. The improved module emphasizes the reduction or elimination of fugitive methane by considering the methane oxidation capacity of the cover system. The module also allows for the installation of biologically active covers or other features designed to enhance methane oxidation. A methane emissions model, CALMIM, was used to assist with an assessment of the methane oxidation

Large scale gas injection test (Lasgit): Results from two gas injection tests

International Nuclear Information System (INIS)

Cuss, R. J.; Harrington, J. F.; Noy, D. J.; Wikman, A.; Sellin, P.

2011-01-01

This paper describes the initial results from a large scale gas injection test (Lasgit) performed at the Aespoe Hard Rock Laboratory (Sweden)). Lasgit is a full-scale field-scale experiment based on the Swedish KBS-3V repository concept, examining the processes controlling gas and water flow in compact buffer bentonite. The first 2 years of the test focused on the artificial hydration of the bentonite buffer. This was followed by a programme of hydraulic and gas injection tests which ran from day 843 to 1110. A further period of artificial hydration occurred from day 1110 to 1385, followed by a more complex programme of gas injection testing which remains on going (day 1385+). After 2 years of hydration, hydraulic conductivity and specific storage values in the lower filter array were found to range from 9 x 10 -14 to 1.6 x 10 -13 m/s and 5.5 x 10 -5 to 4.4 x 10 -4 m -1 respectively, with the injection filter FL903 yielding values of 7.5 x 10 -14 m/s and 2.5 x 10 -5 m -1 . A second set of hydraulic measurements were performed over 1 year and a half later yielding similar values, in the range 7.8 x 10 -14 m/s and 1.3 x 10 -13 m/s. The hydraulic conductivity of FL903 had reduced slightly to 5.3 x 10 -14 m/s while specific storage had increased to 4.0 x 10 -5 m -1 . Both datasets agree with laboratory values performed on small-scale saturated samples. Two sets of gas injection tests were performed over a 3 year period. During the course of testing, gas entry pressure was found to increase from around 650 kPa to approximately 1.3 MPa, indicative of the maturation of the clay. The sequential reduction in volumetric flow rate and lack of correlation between the rate of gas inflow and the gas pressure gradient observed during constant pressure steps prior to major gas entry, is suggestive of a reduction in gas permeability of the buffer and indicates only limited quantities of gas can be injected into the clay without interacting with the continuum stress field. Major gas

Silicon Web Process Development. [for solar cell fabrication

Science.gov (United States)

Duncan, C. S.; Seidensticker, R. G.; Hopkins, R. H.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.

1979-01-01

Silicon dendritic web, ribbon form of silicon and capable of fabrication into solar cells with greater than 15% AMl conversion efficiency, was produced from the melt without die shaping. Improvements were made both in the width of the web ribbons grown and in the techniques to replenish the liquid silicon as it is transformed to web. Through means of improved thermal shielding stress was reduced sufficiently so that web crystals nearly 4.5 cm wide were grown. The development of two subsystems, a silicon feeder and a melt level sensor, necessary to achieve an operational melt replenishment system, is described. A gas flow management technique is discussed and a laser reflection method to sense and control the melt level as silicon is replenished is examined.

Estimated costs of Sustaining Agricultural Production Through Erosional Control and Replenishment of Nutrient Losses in Kenya

International Nuclear Information System (INIS)

Onyango, J.W.

1999-01-01

Soil erosion is one of the major causes of nutrient depletion in sub-Saharan Africa. Highlights of losses from erosion can be used to explain why agricultural production in this region is not sustainable. annual macronutrient losses were calculated from experimental results at 8 sites in Kenya between 1986 and 1990. these losses were used along with the current local prices of fertiliser to estimate the annual national budget required for there replenishment. On average, 5.72, 29.3 and 0.82 kg ha -1 yr -1 of N, P and K, respectively, were lost annually. These losses are determined by soil types, slope, crop cover characteristics and rainfall amounts. soil losses can be reduced by terracing, contour farming and intercropping to improve crop cover. These efforts reduce the adverse effects of sporadic rainfall on fragile soil types. in order to ensure sustainability however, control measures have to be supplemented by national additions of 64 000 t, 323 000 t and 10 000 t of N, P and K respectively per year. The equivalent costs of these fertilisers will be Ksh 1,408 Ksh 8721 Ksh 220 million for the respective nutrients. This would require a total of some US$256 million (Ksh 10 349 million) annually from the national budget

THEORETICAL GAS CONCENTRATIONS ACHIEVING 100% FILL OF THE VITREOUS CAVITY IN THE POSTOPERATIVE PERIOD: A Gas Eye Model Study.

Science.gov (United States)

Williamson, Tom H; Guillemaut, Jean-Yves; Hall, Sheldon K; Hutter, Joseph C; Goddard, Tony

2017-12-11

To determine the concentrations of different gas tamponades in air to achieve 100% fill of the vitreous cavity postoperatively and to examine the influence of eye volume on these concentrations. A mathematical model of the mass transfer dynamics of tamponade and blood gases (O2, N2, and CO2) when injected into the eye was used. Mass transfer surface areas were calculated from published anatomical data. The model has been calibrated from published volumetric decay and composition results for three gases sulphahexafluoride (SF6), hexafluoroethane (C2F6), or perfluoropropane (C3F8). The concentrations of these gases (in air) required to achieve 100% fill of the vitreous cavity postoperatively without an intraocular pressure rise were determined. The concentrations were calculated for three volumes of the vitreous cavity to test whether ocular size influenced the results. A table of gas concentrations was produced. In a simulation of pars plana vitrectomy operations in which an 80% to 85% fill of the vitreous cavity with gas was achieved at surgery, the concentrations of the 3 gases in air to achieve 100% fill postoperatively were 10% to 13% for C3F8, 12% to 15% for C2F6, and 19% to 25% for SF6. These were similar to the so-called "nonexpansive" concentrations used in the clinical setting. The calculations were repeated for three different sizes of eye. Aiming for an 80% fill at surgery and 100% postoperatively, an eye with a 4-mL vitreous cavity required 24% SF6, 15% C2F6, or 13% C3F8; 7.2 mL required 25% SF6, 15% C2F6, or 13% C3F8; and 10 mL required 25% SF6, 16% C2F6, or 13% C3F8. When using 100% gas (e.g., used in pneumatic retinopexy), to achieve 100% fill postoperatively, the minimum vitreous cavity fill at surgery was 43% for SF6, 29% for C2F6, and 25% for C3F8 and was only minimally changed by variation in the size of the eye. A table has been produced, which could be used for surgical innovation in gas usage in the vitreous cavity. It provides concentrations

Hibernation and gas exchange.

Science.gov (United States)

Milsom, William K; Jackson, Donald C

2011-01-01

Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature. © 2011 American Physiological Society.

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Ionization chamber for monitoring radioactive gas

International Nuclear Information System (INIS)

Kotrappa, P.; Dempsey, J.

1992-01-01

This present invention provides simple, effective and accurate cumulative measurement of radioactive gas over a time period. Measurements of radioactive gas are important for many purposes. Tritium concentrations in potentially exposed workers are measured, for example, with periodic urine specimens. Carbon-14 serves as a useful research tool for monitoring the progress of many chemical and biological reactions and interactions. For example, many microorganisms break down carbon-14 containing compounds in sugar to produce carbon-14 dioxide gas which can be collected and measured to determine various characteristics of the microorganisms. Both tritium and carbon-14 dioxide produce low energy radiation which cannot be easily measured by conventional radioactivity detectors. (author). 4 figs

Ionization chamber for monitoring radioactive gas

Energy Technology Data Exchange (ETDEWEB)

Kotrappa, P; Dempsey, J

1992-09-22

This present invention provides simple, effective and accurate cumulative measurement of radioactive gas over a time period. Measurements of radioactive gas are important for many purposes. Tritium concentrations in potentially exposed workers are measured, for example, with periodic urine specimens. Carbon-14 serves as a useful research tool for monitoring the progress of many chemical and biological reactions and interactions. For example, many microorganisms break down carbon-14 containing compounds in sugar to produce carbon-14 dioxide gas which can be collected and measured to determine various characteristics of the microorganisms. Both tritium and carbon-14 dioxide produce low energy radiation which cannot be easily measured by conventional radioactivity detectors. (author). 4 figs.

Order Level Inventory Models for Deteriorating Seasonable/Fashionable Products with Time Dependent Demand and Shortages

Directory of Open Access Journals (Sweden)

K. Skouri

2009-01-01

Full Text Available An order level inventory model for seasonable/fashionable products subject to a period of increasing demand followed by a period of level demand and then by a period of decreasing demand rate (three branches ramp type demand rate is considered. The unsatisfied demand is partially backlogged with a time dependent backlogging rate. In addition, the product deteriorates with a time dependent, namely, Weibull, deterioration rate. The model is studied under the following different replenishment policies: (a starting with no shortages and (b starting with shortages. The optimal replenishment policy for the model is derived for both the above mentioned policies.

The European Market for Seasonal Gas Storage

International Nuclear Information System (INIS)

Mahan, A.

2006-02-01

European demand for gas will grow in the years to come. Simultaneously, gas production in Europe will decrease and imported gas will be needed to replace indigenous production. Gas demand is not constant during the year. There are variations in demand on different timescales ranging from seasonal to hourly. Variations in demand are characterised by two main parameters: working volume and deliverability. Working volume - the amount of gas that can be supplied above the baseload production volume during a long (cold) period- is primarily needed to cope with the summer-winter pattern of gas consumption. Most of the summer-winter pattern comes from the temperature sensitive gas consumption by households and service industries. Gas usage by industry and the power sector are more evenly spread throughout the year and need less working volume. Deliverability - the amount of gas per hour that can be generated on a (very) cold day above the baseload capacity - is the ability to produce large volumes during short periods, e.g. for extremely cold days, or during peak periods during a day. In this paper we argue that a large amount of additional working volume will be required over the coming years. First, flexible European production will be replaced by long-distance import gas, and second, the gas market is expected to grow further. Todays market appears focus mainly on cavems for storage volume. Cavems have little working volume but are ideal for trading purposes. Consequently, Europe may be facing a deficit in working volume, i.e. the ability to cope with seasonal changes in demand. This paper aims to widen the discussion of this matter and give rise to this concern by setting out a broad analysis, exploring the market drivers for seasonal storage and identifying the public interest issues for this market. Chapter 2 gives an overview of demand for and supply characteristics of gas flexibility. Chapter 3 describes the role of gas storage facilities in the gas market

New oil and gas discoveries

International Nuclear Information System (INIS)

Alazard-Toux, N.

2004-01-01

During the period 1999-2003, new oil and gas fields generated additional reserves of nearly 11 000 bcm of natural gas and 62 Gbbl of oil and condensates, volumes very much superior to those discovered in the five previous years. Two-thirds of these discoveries were located offshore, half in deep water. (author)

Gas hydrate cool storage system

Science.gov (United States)

Ternes, M.P.; Kedl, R.J.

1984-09-12

The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

Exergy analysis of waste emissions from gas flaring

Directory of Open Access Journals (Sweden)

Olawale Saheed ISMAIL

2016-07-01

Full Text Available Gas flaring produces a stream of waste gases at high temperature and pressure which contains carbon monoxide, Hydrogen Sulphide etc. The resultant effect of which is detrimental to our planet and, consequently, to the life of both the living and the non-living things. It’s well known that gas flaring contributes in no small measure to the global warming. Exergy analysis is applied in this work to analyze waste emissions from gas flaring so as to have a model through which impact of gas flaring can be measured. The study considers both the thermo-mechanical exergy and the chemical exergy of these gases. Relevant data on gas flaring activities in the Niger-Delta region of Nigeria between the periods of fifteen (15 years was obtained from the Nigerian National Petroleum Corporation (NNPC. A computer program (Exergy Calculator was developed based on the equations generated in the Model. Exergy associated with gas flaring activities in Nigeria between the periods of 1998 through 2012 was calculated. The results show that 1 mscf (in thousand cubic feet of flared gases generate 0.000041 MWh of energy leading to a value of 440158.607 MWh of energy for the period under review.The analysis provides important conclusions and recommendations for improving oil platforms operationsin in order to safeguard the environment, health of the populace, and maximize recovered exergy from gas flaring.

The effectiveness of policies to transform a gas-exporting country into a gas-transit country: The case of The Netherlands

International Nuclear Information System (INIS)

Schipperus, Ouren T.; Mulder, Machiel

2015-01-01

The Netherlands has been a major European natural gas producer and exporter for many decades, but now faces the challenge to deal with diminishing resources. In response, the Dutch government initiated a gas-hub strategy, which is the policy to transform the gas industry from an export-oriented business into a transit-oriented business. This policy included a number of investments in the gas infrastructure as well as institutional reforms to enhance the liquidity of the gas market. We study the effects of this gas-hub policy. Using hourly data on the Dutch gas balance over the period 2006–2013, we find that gas storage and trading have become more important, but that the level of gas in transit in the Netherlands remained fairly constant. Consequently, the Dutch gas industry is still mainly oriented on domestic production and export of gas, while the Dutch gas hub (TTF) has become a key virtual trading place. The policy lesson from the Dutch experience is that implementing a gas-hub strategy requires significant investments in the gas infrastructure, while their effects do not necessarily become visible in the short run. -- Highlights: •The Netherlands has been a major gas producer and exporter for decades. •This country implemented a gas hub policy to deal with diminishing resources. •We study the effects of this policy using hourly data over the period 2006–2013. •Storage and trading became more important, but transit hardly grew. •The investments in the gas hub did not have clear effects in the short term

Lattice Model for Production of Gas

KAUST Repository

Marder, M.; Eftekhari, Behzad; Patzek, Tadeusz

2017-01-01

We define a lattice model for rock, absorbers, and gas that makes it possible to examine the flow of gas to a complicated absorbing boundary over long periods of time. The motivation is to deduce the geometry of the boundary from the time history

Radiolytic gas generation in plutonium contaminated waste materials

International Nuclear Information System (INIS)

Kazanjian, A.R.

1976-01-01

Many plutonium contaminated waste materials decompose into gaseous products because of exposure to alpha radiation. The gases generated (usually hydrogen) over long-storage periods may create hazardous conditions. To determine the extent of such hazards, knowing the gas generation yields is necessary. These yields were measured by contacting some common Rocky Flats Plant waste materials with plutonium and monitoring the enclosed atmospheres for extensive periods of time. The materials were Plexiglas, polyvinyl chloride, glove-box gloves, machining oil, carbon tetrachloride, chlorothene VG solvent, Kimwipes (dry and wet), polyethylene, Dowex-1 resin, and surgeon's gloves. Both 239 Pu oxide and 238 Pu oxide were used as radiation sources. The gas analyses were made by mass spectrometry and the results obtained were the total gas generation, the hydrogen generation, the oxygen consumption rate, and the gas composition over the entire storage period. Hydrogen was the major gas produced in most of the materials. The total gas yields varied from 0.71 to 16 cm 3 (standard temperature pressure) per day per curie of plutonium. The oxygen consumption rates varied from 0.0088 to 0.070 millimoles per day per gram of plutonium oxide-239 and from 0.0014 to 0.0051 millimoles per day per milligram 238 Pu

Replenishment policy for Entropic Order Quantity (EnOQ model with two component demand and partial back-logging under inflation

Directory of Open Access Journals (Sweden)

Bhanupriya Dash

2017-09-01

Full Text Available Background: Replenishment policy for entropic order quantity model with two component demand and partial backlogging under inflation is an important subject in the stock management. Methods: In this paper an inventory model for  non-instantaneous  deteriorating items with stock dependant consumption rate and partial back logged in addition the effect of inflection and time value of money on replacement policy with zero lead time consider was developed. Profit maximization model is formulated by considering the effects of partial backlogging under inflation with cash discounts. Further numerical example presented to evaluate the relative performance between the entropic order quantity and EOQ models separately. Numerical example is present to demonstrate the developed model and to illustrate the procedure. Lingo 13.0 version software used to derive optimal order quantity and total cost of inventory. Finally sensitivity analysis of the optimal solution with respect to different parameters of the system carried out. Results and conclusions: The obtained inventory model is very useful in retail business. This model can extend to total backorder.

Business cycles and natural gas prices

International Nuclear Information System (INIS)

Apostolos, S.; Asghar, S.

2005-01-01

This paper investigates the basic stylised facts of natural gas price movements using data for the period that natural gas has been traded on an organised exchange and the methodology suggested by Kydland and Prescott (1990). Our results indicate that natural gas prices are procyclical and lag the cycle of industrial production. Moreover, natural gas prices are positively contemporaneously correlated with United States consumer prices and lead the cycle of consumer prices, raising the possibility that natural gas prices might be a useful guide for US monetary policy, like crude oil prices are, possibly serving as an important indicator variable. (author)

Natural gas benefits

International Nuclear Information System (INIS)

1999-01-01

The General Auditor in the Netherlands studied the natural gas policy in the Netherlands, as has been executed in the past decades, in the period 1997-1999. The purpose of the study is to inform the Dutch parliament on the planning and the backgrounds of the natural gas policy and on the policy risks with respect to the benefits for the Dutch State, taking into account the developments in the policy environment. The final conclusion is that the proposed liberalization of the national natural gas market will result in a considerable deprivation of income for the State in case the benefit policy is not adjusted. This report includes a reaction of the Dutch Minister of Economic Affairs and an afterword of the General Auditor. In the appendix an outline is given of the natural gas policy

Determination of benzene in exhaust gas from biofuels. Final report; Bestimmung von Benzol im Abgas von Biokraftstoffen. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Dutz, M.; Buenger, J.; Gnuschke, H.; Halboth, H.; Gruedl, P.; Krahl, J.

2001-10-01

With the advance of environmental legislation and practices oriented towards sustainability renewable energy resources are becoming increasingly important. Use of replenishable raw materials helps preserve fossil resources. In the fuel sector the most widely used replenishable materials are rape methyl ester (RME) and ethyl tertiary butyl ether (ETBE). The purpose of the present project on the ''Determination of benzene in exhaust gas from biofuels'' was to generate orienting data on the potential health relevance of mixtures of fossil and renewable fuel intended for use in spark ignition and diesel engines. This included a determination of benzene emissions and the mutagenicity of particles. Beyond the applied-for scope of research measurements were also performed on the test engine's toluene, ethyl benzene and xylene emissions as well as on the smoke spot number and nitrogen oxide (NO{sub x}) and hydrocarbon (HC) emissions of the diesel engine. [German] Regenerative Energien gewinnen durch die Umweltgesetzgebungen und das Streben nach einer nachhaltigen Entwicklung zunehmend an Bedeutung. Durch die Verwendung nachwachsender Rohstoffe koennen die fossilen Ressourcen geschont werden. Im Kraftstoffsektor sind hier hauptsaechlich Rapsoelmethylester (RME) und optional Ethyltertiaerbutylether (ETBE) zu nennen. Um fuer Diesel- und Ottomotoren insbesondere mit Blick auf Kraftstoffgemische aus fossilen und regenerativen Komponenten orientierende Daten ueber eine potenzielle Gesundheitsrelevanz zu generieren, wurde das Projekt 'Bestimmung von Benzol im Abgas von Biokraftstoffen' durchgefuehrt. Neben der Benzolemission wurde die Mutagenitaet der Partikeln ermittelt. Ueber den beantragten Untersuchungsrahmen hinaus wurden die Tuluol-, Ethylbenzol-, und Xylolemissionen der eingesetzten Motoren, sowie die Russzahl (RZ) und die Stickoxid- (NO{sub x}) und Kohlenwasserstoffemissionen (HC) des Dieselmotors bestimmt. (orig.)

Lattice Model for Production of Gas

KAUST Repository

Marder, M.

2017-12-01

We define a lattice model for rock, absorbers, and gas that makes it possible to examine the flow of gas to a complicated absorbing boundary over long periods of time. The motivation is to deduce the geometry of the boundary from the time history of gas absorption. We find a solution to this model using Green\\'s function techniques, and apply the solution to three absorbing networks of increasing complexity.

Lattice Model for Production of Gas

OpenAIRE

Marder, M.; Eftekhari, Behzad; Patzek, Tadeusz W

2017-01-01

We define a lattice model for rock, absorbers, and gas that makes it possible to examine the flow of gas to a complicated absorbing boundary over long periods of time. The motivation is to deduce the geometry of the boundary from the time history of gas absorption. We find a solution to this model using Green's function techniques, and apply the solution to three absorbing networks of increasing complexity.

Hydrogen purification by periodic adsorption

Energy Technology Data Exchange (ETDEWEB)

Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

2000-07-01

The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

Rising prices squeeze gas marketer

Energy Technology Data Exchange (ETDEWEB)

Lunan, D.

2000-06-19

Apollo Gas, a Toronto-based gas marketer, is considering options to enhance unit holder value, including sale of its 21,000 gas supply contracts, just weeks after it was forced out of the Alberta market by rising gas prices. Although the company had reported first quarter revenues of more than $15 million and earnings through that period of about $2.1 million, increases of 33 per cent and 38 per cent respectively over the same period in 1999, the company is resigned to the fact that such performance markers are not likely to be reached again in the foreseeable future, hence the decision to sell. About 95 per cent of Apollo's current transportation service volumes are matched to existing fixed-price supply contract which are due to expire in November 2000. After that, it is about 75 per cent matched for the balance of the term of its customer contracts (mostly five years). This means that the company is exposed to market prices that are likely to continue to increase. If this prediction holds true, Apollo would be forced to purchase the unhedged volumes of gas it needs to service its customers in the spot market at prices higher than prices the company is charging to its customers.

Rising prices squeeze gas marketer

International Nuclear Information System (INIS)

Lunan, D.

2000-01-01

Apollo Gas, a Toronto-based gas marketer, is considering options to enhance unit holder value, including sale of its 21,000 gas supply contracts, just weeks after it was forced out of the Alberta market by rising gas prices. Although the company had reported first quarter revenues of more than $15 million and earnings through that period of about $2.1 million, increases of 33 per cent and 38 per cent respectively over the same period in 1999, the company is resigned to the fact that such performance markers are not likely to be reached again in the foreseeable future, hence the decision to sell. About 95 per cent of Apollo's current transportation service volumes are matched to existing fixed-price supply contract which are due to expire in November 2000. After that, it is about 75 per cent matched for the balance of the term of its customer contracts (mostly five years). This means that the company is exposed to market prices that are likely to continue to increase. If this prediction holds true, Apollo would be forced to purchase the unhedged volumes of gas it needs to service its customers in the spot market at prices higher than prices the company is charging to its customers

Securing growth markets for natural gas

International Nuclear Information System (INIS)

Evans, G.

1999-01-01

The Industry Development Strategy 2000-2005 (IDS) identifies the major growth markets for natural gas, as the industry readies itself for the challenges of the new millenium. An integral part of this process is to examine the key barriers to market expansion, and to devise strategies that both The Australian Gas Association (AGA) and the wider industry can pursue to underpin improvement in overall gas consumption. This is the task of the IDS which examines the opportunities confronting the industry over the next five year period. The significant growth prospects of the gas industry both in the short term (2000-2005) and long term (2005-2015) are indicated in two comprehensive and independent studies. The first, Australian Energy Market Developments and Projections to 2014-15, was released earlier this year by the Australian Bureau of Agricultural and Resource Economics (the ABARE Energy Report). The second, Natural Gas Consumption in Australia to 2015-Prospects by State, Industry and Sector, was commissioned by the AGA, and was completed by the National Institute of Economic and Industry Research in September 1999 (NIEIR Report). Both reports indicate that in terms of consumption levels, in the period up to 2015 the gas industry is forecast to more than double its current size. Natural gas is also projected to increase its primary energy share ranking from third to second place

Modelling gas generation in radioactive waste repositories

International Nuclear Information System (INIS)

Agg, P.J.

1993-02-01

In a repository containing low- and intermediate-level waste, gas generation will occur principally by the coupled processes of metal corrosion and microbial degradation of cellulosic waste. This Paper describes a mathematical model design to address gas generation by these mechanisms. The metal corrosion model incorporates a three-stage process encompassing both aerobic and anaerobic corrosion regimes; the microbial degradation model simulates the activities of eight different microbial populations, which are maintained as functions both of pH and of the concentrations of particular chemical species. Gas concentrations have been measured over a period of three years in large-scale drum experiments designed to simulate repository conditions. Model predictions are confirmed against the experimental measurements, and a prediction is then made of gas concentrations and generation rates over an assessment period of one million years in a radioactive waste repository. (author)

Modelling gas generation in radioactive waste repositories

International Nuclear Information System (INIS)

Agg, P.J.

1992-07-01

In a repository containing low- and intermediate-level waste, gas generation will occur principally by the coupled processes of metal corrosion and microbial degradation of cellulosic waste. This paper describes a mathematical model designed to address gas generation by these mechanisms. The metal corrosion model incorporates a three-stage process encompassing both aerobic and anaerobic corrosion regimes; the microbial degradation model simulates the activities of eight different microbial populations, which are maintained as functions both of pH and of the concentrations of particular chemical species. Gas concentrations have been measured over a period of three years in large-scale drum experiments designed to simulate repository conditions. Model predictions are confirmed against the experimental measurements, and a prediction is then made of gas concentrations and generation rates over an assessment period of one million years in a radioactive waste repository. (Author)

Active Galactic Nuclei Feedback and the Origin and Fate of the Hot Gas in Early-type Galaxies

Science.gov (United States)

Pellegrini, Silvia; Ciotti, Luca; Negri, Andrea; Ostriker, Jeremiah P.

2018-04-01

A recent determination of the relationships between the X-ray luminosity of the ISM (L X) and the stellar and total mass for a sample of nearby early-type galaxies (ETGs) is used to investigate the origin of the hot gas, via a comparison with the results of hydrodynamical simulations of the ISM evolution for a large set of isolated ETGs. After the epoch of major galaxy formation (after z ≃ 2), the ISM is replenished by stellar mass losses and SN ejecta, at the rate predicted by stellar evolution, and is depleted by star formation; it is heated by the thermalization of stellar motions, SNe explosions, and the mechanical (from winds) and radiative AGN feedback. The models agree well with the observed relations, even for the largely different L X values at the same mass, thanks to the sensitivity of the gas flow to many galaxy properties; this holds for models including AGN feedback, and those without. Therefore, the mass input from the stellar population is able to account for a major part of the observed L X; and AGN feedback, while very important to maintain massive ETGs in a time-averaged quasi-steady state, keeping low star formation and the black hole mass, does not dramatically alter the gas content originating in stellar recycled material. These conclusions are based on theoretical predictions for the stellar population contributions in mass and energy, and on a self-consistent modeling of AGN feedback.

Methodology for flammable gas evaluations

Energy Technology Data Exchange (ETDEWEB)

Hopkins, J.D., Westinghouse Hanford

1996-06-12

There are 177 radioactive waste storage tanks at the Hanford Site. The waste generates flammable gases. The waste releases gas continuously, but in some tanks the waste has shown a tendency to trap these flammable gases. When enough gas is trapped in a tank`s waste matrix, it may be released in a way that renders part or all of the tank atmosphere flammable for a period of time. Tanks must be evaluated against previously defined criteria to determine whether they can present a flammable gas hazard. This document presents the methodology for evaluating tanks in two areas of concern in the tank headspace:steady-state flammable-gas concentration resulting from continuous release, and concentration resulting from an episodic gas release.

Periodicity in the BrO/SO2 molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Science.gov (United States)

Dinger, Florian; Bobrowski, Nicole; Warnach, Simon; Bredemeyer, Stefan; Hidalgo, Silvana; Arellano, Santiago; Galle, Bo; Platt, Ulrich; Wagner, Thomas

2018-03-01

We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change) gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador) for BrO/SO2 molar ratios. The BrO/SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua) suggest a possible link between a drop in BrO/SO2 and a future explosion. In addition, the observed relatively high BrO/SO2 molar ratios after December 2015 imply that bromine degassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on volcanic gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO/SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO/SO2 molar ratios with the north-south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO/SO2 molar ratios and the relative humidity in the local

Quickening construction of natural gas infrastructures and ensuring safe supply of natural gas in China

Energy Technology Data Exchange (ETDEWEB)

Gao, Peng; Zhongde, Zhao; Chunliang, Sun; Juexin, Shen

2010-09-15

Compared with North America or Europe in respect of natural gas resources, markets and pipeline networks, the current China stands in a special period with natural gas market in quick development, accordingly, it's recommended to strengthen cooperation and coordination between investors by way of diversified investment and joint adventures and on the basis of diversified resource supply modes, so as to accelerate the construction of infrastructures including the natural gas pipeline networks and the storage and peak-shaving facilities, quick up the market development, realize the situation of mutual-win-win, and finally ensure safety of natural gas utilization in the domestic markets.

Mitochondrial GSH replenishment as a potential therapeutic approach for Niemann Pick type C disease

Directory of Open Access Journals (Sweden)

Sandra Torres

2017-04-01

Full Text Available Niemann Pick type C (NPC disease is a progressive lysosomal storage disorder caused by mutations in genes encoding NPC1/NPC2 proteins, characterized by neurological defects, hepatosplenomegaly and premature death. While the primary biochemical feature of NPC disease is the intracellular accumulation of cholesterol and gangliosides, predominantly in endolysosomes, mitochondrial cholesterol accumulation has also been reported. As accumulation of cholesterol in mitochondria is known to impair the transport of GSH into mitochondria, resulting in mitochondrial GSH (mGSH depletion, we investigated the impact of mGSH recovery in NPC disease. We show that GSH ethyl ester (GSH-EE, but not N-acetylcysteine (NAC, restored the mGSH pool in liver and brain of Npc1-/- mice and in fibroblasts from NPC patients, while both GSH-EE and NAC increased total GSH levels. GSH-EE but not NAC increased the median survival and maximal life span of Npc1-/- mice. Moreover, intraperitoneal therapy with GSH-EE protected against oxidative stress and oxidant-induced cell death, restored calbindin levels in cerebellar Purkinje cells and reversed locomotor impairment in Npc1-/- mice. High-resolution respirometry analyses revealed that GSH-EE improved oxidative phosphorylation, coupled respiration and maximal electron transfer in cerebellum of Npc1-/- mice. Lipidomic analyses showed that GSH-EE treatment had not effect in the profile of most sphingolipids in liver and brain, except for some particular species in brain of Npc1-/- mice. These findings indicate that the specific replenishment of mGSH may be a potential promising therapy for NPC disease, worth exploring alone or in combination with other options.

Productivity changes in the Gas and Fuel Corporation of Victoria

International Nuclear Information System (INIS)

Rushdi, A.

1994-01-01

The study reveals that the total factor productivity in the Gas and Fuel Corporation of Victoria (GFCV) continued to increase throughout the study period except for a brief period between 1983-84 and 1984-85 which was mainly the result of the decline in the industrial demand for gas and a decelerated growth rate in residential demand. The productivity gains were found to be highly sensitive to the rates of depreciation and discount rates assumed. The estimated terms of trade suggest that the increase in gas prices was lower that the increase in the aggregate input prices the GFCV paid, particularly to capital and labour. However, while the price index of reticulated gas increased to 2.17, the purchase price declined to 0.96 over the study period. The productivity gains by GFCV seem to have been shared with its customers. (Author)

Mathematical models of natural gas consumption

International Nuclear Information System (INIS)

Sabo, Kristian; Scitovski, Rudolf; Vazler, Ivan; Zekic-Susac, Marijana

2011-01-01

In this paper we consider the problem of natural gas consumption hourly forecast on the basis of hourly movement of temperature and natural gas consumption in the preceding period. There are various methods and approaches for solving this problem in the literature. Some mathematical models with linear and nonlinear model functions relating to natural gas consumption forecast with the past natural gas consumption data, temperature data and temperature forecast data are mentioned. The methods are tested on concrete examples referring to temperature and natural gas consumption for the area of the city of Osijek (Croatia) from the beginning of the year 2008. The results show that most acceptable forecast is provided by mathematical models in which natural gas consumption and temperature are related explicitly.

Asia Gas Study

International Nuclear Information System (INIS)

1996-01-01

The Asia region has experienced a period of dynamic growth, both of economies and energy demand. The next fifteen years are likely to see further rapid economic growth in Asia. To fuel this growth energy consumption will also increase rapidly. Of all forms of energy, natural gas demand is likely to grow the fastest. The gas sector will face rapid and dramatic change, creating challenges for the governments of the region. Infrastructure, both for export and domestic consumption of gas, will need to expand significantly. Regional trade in natural gas could triple by 2010. Trade will continue to be dominated by liquefied natural gas (LNG) but pipeline exports will also grow rapidly. Investment needs will be large, putting pressure on governments to look for alternative funding mechanisms. As Asian gas transmission and distribution networks expand and become more interconnected, consumer choice becomes possible. How to encourage and regulate competition will become a vital policy question. As gas consumption increases both in absolute terms, and in terms of its share of energy consumption within particular sectors of the economy (for example, as a fuel for power generation), governments will need to give higher priority to policies dealing with gas security. This study examines the current and possible future role of natural gas in Asia. In particular, it examines in detail the relevant energy policies of six of the key gas producing and consuming economies in the region: Brunei-Darussalam, Chinese Taipei, Indonesia, the Republic of Korea, Malaysia and Thailand. (author). 17 figs., 14 tabs., 7 appends

Research on Factors Affecting the Optimal Exploitation of Natural Gas Resources in China

Directory of Open Access Journals (Sweden)

Jianzhong Xiao

2016-05-01

Full Text Available This paper develops an optimizing model for the long-term exploitation of limited natural gas reserves in China. In addition to describing the life cycle characteristics of natural gas production and introducing the inter-temporal allocation theory, this paper builds the optimal exploitation model of natural gas resources within a gas field in the Ordos Basin as an example to analyze its exploitation scale and how influence factors, such as recovery rate, discount rate and the gas well exhausting cycle, affect the optimal exploration path of this gas field. We determine that an increase in the discount rate stimulates investors to invest more aggressively in natural gas exploitation in the early period due to the lower discounted value, thereby increasing the pace of the exploitation of natural gas and the exhaustion of gas fields. A higher recoverable factor implies more recoverable reserves and greater potential of increasing the output of gas fields. The exhaustion rate of gas wells affects the capability of converting capacity to output. When exhaustion occurs quickly in gas wells, the output will likely increase in the output rising period, and the output will likely decrease at a faster rate in the output reduction period. Price reform affects the economic recoverable reserves of gas fields.

Gas tax/public transit annual expenditure report pursuant to the agreement on the transfer of federal gas tax revenue and the agreement on the transfer of public transit funds for the period April 1, 2006 to March 31, 2007

International Nuclear Information System (INIS)

Binnie, B.; Taylor, R.; Gibson, B.

2007-09-01

Federal funding initiatives for local infrastructure and capacity building was discussed with particular reference to the unique partnerships between the Canada-British Columbia Agreement on the transfer of federal gas tax revenues and the Canada-British Columbia agreement on the transfer of funds for public transit. The agreements reflect the nature of intergovernmental relations in British Columbia where the Union of British Columbia Municipalities (UBCM) works together with both federal and provincial governments to promote sustainable communities. This report identified the initiatives that are underway in communities across British Columbia as they begin to implement Gas Tax and Public Transit funded projects. These projects span a broad range of eligible project categories. The leadership role taken by local governments in the province to reduce greenhouse gas emissions was highlighted. Some of the 141 projects reported in 2007 were highlighted in this report, including improvement to public transit in the District of Saanich; TransLink bus replacement and expansion; cycling and pedestrian infrastructure; improvements to local roads and bridges; alternative energy retrofits; collection of solid waste; improvement to water systems; stormwater and wastewater treatment; capacity building; watershed protection; and water acquisition strategies. Of the projects reported, 33 per cent anticipated gas tax spending in more than 1 year, indicating either payment of capital costs as they are incurred during a construction period that spans beyond a single year, or use of gas tax funding towards the debt servicing costs related to the eligible project. tabs., figs

Survey of landfill gas generation potential

International Nuclear Information System (INIS)

Gauntlett, W.D.

1992-09-01

This project identifies all the landfill sites in each of the 50 states capable of producing 750,000 SCFD of mixed landfill gas for a period of at least 10 years. The study identified 749 landfill sites nationally, with an aggregate gas production rate sufficient to fuel approximately 6000 MW of fuel cell power plants

The Role of Gas in the European Energy Transition: Challenges and Opportunities

International Nuclear Information System (INIS)

Cornot-Gandolphe, Sylvie

2018-01-01

Following difficult years for the European gas industry, natural gas is back to the front stage. Given its environmental credentials, its flexibility, its performance and the variety of its uses, gas has a key role to play in the reduction of greenhouse gas emissions, the improvement of air quality, the integration of intermittent renewable energy sources in the power mix. Its role will evolve in the longer term and one must distinguish the period 2015-2030 from the period 2030-2050

Physiological, biochemical and productive changes in sesame genotypes subjected to different rates of water replenishment

Directory of Open Access Journals (Sweden)

Maria S. R. Lima

Full Text Available ABSTRACT The sesame crop has stood out due to the high nutritional content of its seeds, in addition to being able to be cultivated in the tropical and subtropical regions such as Northeast Brazil. Thus, it is necessary to identify the physiological, biochemical and productive changes related to the tolerance to stress. Objective of this study was to evaluate the physiological, biochemical and productive aspects of sesame genotypes as a function of different rates of water replenishment. The experiment was carried out at the Embrapa Cotton Experimental Unit, located in the municipality of Barbalha-CE, Brazil, under field conditions. The experiment was carried out in a randomized complete block design, with treatments in a factorial scheme (4 × 6, corresponding to four irrigation depths (40, 70, 100 and 130% ETo and six sesame genotypes (G1 = T3-EGSGO3; G2 = T7-EGSGO7; G3 = T5-EGSGO5; G4 = T2-EGSGO2; G5 = T6-EGSGO6; G6 = T4-EGSG04, with three replicates. Data corresponding to the following variables were collected: leaf area, photosynthetic pigments, relative water content in leaf, electrolyte leakage, catalase, peroxidase, yield and oil content. The genotypes did not differ statistically and there were differences in the variables between the water replacement rates. Increments in growth and, consequently, in production, enzymatic activity, oil content and maximum production potential were observed with water depths between 75 and 90% ETo. Contents of chlorophyll a and b, total chlorophyll and carotenoids, were increased with the application of 80% ETo.

Greenhouse gas emissions in Europe: a retrospective trend analysis for the period 1990-2008

Energy Technology Data Exchange (ETDEWEB)

Borgan, A.; Gugele, B.; Haider, S. (Umweltbundesamt, Vienna (Austria)) (and others)

2011-10-15

This report presents a retrospective overview of the greenhouse gas (GHG) emission trends in Europe from 1990 to 2008, with a particular focus on the underpinning drivers and the influence of EU policies. The analysis is based on the combination of decomposition analyses to identify the respective influence of each identified driver and an overview of the main EU policies and their likely effects on these drivers. The period covered by the analysis stops in 2008. As a result, the analysis avoids the effects of the recent economic crisis on GHG emissions. This reinforces the conclusion on long-term emission drivers. The report covers the EU-27 and presents results for the other EEA member countries (Iceland, Liechtenstein, Norway, Switzerland and Turkey) and Croatia (EU candidate country together with Turkey) as far as data is available. The results can be summarized as: 1) Overall GHG emission trends. EU GHG emissions were reduced between 1990 and 2008. Most of the reductions took place in the 1990s, but emissions have also been decreasing every year from 2003 until the last year considered in this report, 2008. 2) Predominant drivers. For the most part, the GHG emission trends observed in the EU between 1990 and 2008 resulted from economic factors. However, EU policies, some of which were not directly targeting GHG emissions, as well as national policies by some front runner countries, also played a role in these trends. 3) Impacts of EU policies. Between 2000 and 2008, emission trends were more directly targeted by a range of energy and climate policies, e.g. the implementation of the European Climate Change programme. However, the steady increase in energy demand during this period - particularly electricity - outweighed the considerable EU-wide savings generated by energy efficiency improvements and the development of renewable energy. 4) Co-benefits. Taking example from the positive benefits on GHG emissions that resulted from the implementation of non

Demand and supply in Russian gas market

International Nuclear Information System (INIS)

Milovidov, K.N.

1997-01-01

The big volume of gas supplies for current and future energy and natural gas balances in Russia is important to understand the likely future dynamics of demand for gas. The path of future demand in Russia is uncertain and the range of possible scenarios is wide. For creating the new gas consumption structure, more deep diversification and development of the gas distribution systems, large investments and considerable periods of time are necessary. The factors usually studied in detail in the conditions of market economy can not be used here as a basis for strategic planning due to several reasons. (R.P.)

Implementação de um sistema Collaborative Planning, Forecasting, and Replenishment em uma grande rede de fast food por meio de um prestador de serviços logísticos Implementation of a Collaborative Planning, Forecasting, and Replenishment system in a large fast food company through a logistics provider

Directory of Open Access Journals (Sweden)

Mauro Vivaldini

2008-12-01

Full Text Available A gestão colaborativa é, atualmente, um elemento-chave no contexto da gestão da cadeia de suprimentos. Neste artigo, o tema é abordado mediante a análise de um caso real, em que uma grande rede mundial de fast-food e seu prestador de serviço logístico (PSL trabalharam conjuntamente no Brasil em um projeto-piloto para a implementação de um collaborative planning, forecasting, and replenishment (CPFR. O trabalho faz uso de uma metodologia de pesquisa-ação e apresenta as principais variáveis que influenciaram o projeto, abordando os processos necessários para a implementação e os pontos que favorecem o CPFR. Com base no caso estudado, o trabalho apresenta um conjunto de propostas sobre o papel dos agentes da cadeia em projetos dessa natureza. A gestão da cadeia de suprimentos por intermédio da coordenação direta de um PSL também permite demonstrar as possibilidades e dificuldades desse sistema, contribuindo com a visão colaborativa na cadeia de suprimentos a partir da relação entre seus agentes.Nowadays, Collaborative Planning has been considered a key element in the Supply Chain Management context. In this article, this topic is addressed by a real case where a large worldwide fast-food network and its logistics provider worked together in Brazil in a pilot project in order to implement a Collaborative Planning, Forecasting, and Replenishment (CPFR system. Based on an action research approach, this paper presents the main variables that influenced the real project embracing the necessary processes, and it points out those that leveraged the CPFR implementation. Based on the case studied, a set of proposals about the role of the supply chain agents in similar projects is presented. Moreover, the case of conducting the supply chain management by a direct coordination of a logistics provider also allows to highlight the possibilities and difficulties of the CPFR system and to contribute towards a supply chain agents

Method and means for filtering polychlorinated biphenyls from a gas stream

International Nuclear Information System (INIS)

Sowinski, R.F.

1992-01-01

This patent describes a method of filtering, adjacent to an end user-customer's residence or business in which at least a single gas appliance is located, a natural gas stream in which polychlorinated biphenyls (PCB's) and degraded PCB products have been concentrated at sufficient levels to be a health threat in a natural gas gathering and distributing network. It comprises: introducing the natural gas stream to a filter selected from a group that includes impingement, absorbing and adsorbing media whereby PCB's and degraded PCB products concentrated in the gas stream at sufficient levels to be a health threat by a periodic loading of the natural gas within the gathering and distributing network, are filtered from the gas stream and captured irrespective of mode of transport, passing the filtered natural gas stream to the customer's gas appliance wherein safe use of the energy associated with the stream occurs; periodically and safely removing the filter, inserting a new filter in place of the removed filter

Charged particle counters in the pre-modern period

International Nuclear Information System (INIS)

Beringer, R.

1979-01-01

The history of nuclear particle and radiation counting techniques divides itself naturally into three epochs that may be labeled: Early, Pre-Modern, and Modern. The Pre-Modern era is designated as the period starting in the 1930's during which the several types of gas-ionization counters of the Early period were perfected and coupled to vacuum tube circuits and recording apparatus. These developments are briefly discussed. (Auth.)

Gas Hydrate Storage of Natural Gas

Energy Technology Data Exchange (ETDEWEB)

Rudy Rogers; John Etheridge

2006-03-31

Environmental and economic benefits could accrue from a safe, above-ground, natural-gas storage process allowing electric power plants to utilize natural gas for peak load demands; numerous other applications of a gas storage process exist. A laboratory study conducted in 1999 to determine the feasibility of a gas-hydrates storage process looked promising. The subsequent scale-up of the process was designed to preserve important features of the laboratory apparatus: (1) symmetry of hydrate accumulation, (2) favorable surface area to volume ratio, (3) heat exchanger surfaces serving as hydrate adsorption surfaces, (4) refrigeration system to remove heat liberated from bulk hydrate formation, (5) rapid hydrate formation in a non-stirred system, (6) hydrate self-packing, and (7) heat-exchanger/adsorption plates serving dual purposes to add or extract energy for hydrate formation or decomposition. The hydrate formation/storage/decomposition Proof-of-Concept (POC) pressure vessel and supporting equipment were designed, constructed, and tested. This final report details the design of the scaled POC gas-hydrate storage process, some comments on its fabrication and installation, checkout of the equipment, procedures for conducting the experimental tests, and the test results. The design, construction, and installation of the equipment were on budget target, as was the tests that were subsequently conducted. The budget proposed was met. The primary goal of storing 5000-scf of natural gas in the gas hydrates was exceeded in the final test, as 5289-scf of gas storage was achieved in 54.33 hours. After this 54.33-hour period, as pressure in the formation vessel declined, additional gas went into the hydrates until equilibrium pressure/temperature was reached, so that ultimately more than the 5289-scf storage was achieved. The time required to store the 5000-scf (48.1 hours of operating time) was longer than designed. The lower gas hydrate formation rate is attributed to a

Regional Cooperation Towards Trans-country Natural Gas Market

DEFF Research Database (Denmark)

Shukla, P.R.; Dhar, Subash

2009-01-01

India began gas imports since 2004 through liquified natural gas (LNG) route. Imports through trans-country gas pipelines could help in bringing gas directly into the densely populated Northern part of India, which are far from domestic gas resources as well as coastal LNG terminals. The purpose ...... of this paper is to report scenarios, which quantify the impacts for India of regional cooperation to materialize trans-country pipelines. The analysis covers time period from 2005 to 2030.......India began gas imports since 2004 through liquified natural gas (LNG) route. Imports through trans-country gas pipelines could help in bringing gas directly into the densely populated Northern part of India, which are far from domestic gas resources as well as coastal LNG terminals. The purpose...

Method of storing radioactive rare gas. [gas occupies spaces in the zeolite crystal lattice

Energy Technology Data Exchange (ETDEWEB)

Nagao, H; Miharada, H; Takiguchi, Y; Kanazawa, T; Soya, M

1975-05-15

A method is provided to prevent dispersion of radioactive rare gas atoms by sealing them in a pressurised state within zeolite and thereby confining them in position within the zeolite crystal lattice. Radioactive rare gas is separated from exhaust gas and concentrated by using a low temperature adsorption means or liquefaction distillation means and necessary accessory means, and then it is temporarily stored in a gas holder. When a predetermined quantity of storage is reached, the gas is led to a sealing tank containing zeolite heated to 300 to 400/sup 0/C and held at 3,000 to 4,000 atmospheres, and under this condition radioactive rare gas is brought to occupy the spaces in the zeolite crystal lattice. After equilibrium pressure is reached by the pressure in the tank at that temperature, the gas is cooled in the pressurised state down to room temperature. Subsequently, the rare gas remaining in the tank and duct is recovered by a withdrawal pump into the gas holder. Thereafter, the zeolite with radioactive rare gas sealed in it is taken out from the tank and sealed within a long period storage container, which is then housed in a predetermined place for storage.

Behavior of radionuclides in nuclear gas stimulation applications

Energy Technology Data Exchange (ETDEWEB)

Smith, Jr, C F [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-01

The Gasbuggy experiment has presented a unique opportunity to investigate the behavior of radionuclides over an extended period of time in a somewhat unusual environment. In addition to the obvious practical utility of this investigation for Plowshare applications, the information gained has value of a purely scientific nature. Both aspects of the Gas Quality program for Gasbuggy are discussed in this presentation. The study of Gasbuggy results is divided into two distinct periods, according to the field operations. During the initial six months following detonation, the chimney reentry well was shut-in, and the nuclear chimney served as a chemical and radiochemical reaction vessel. A detailed examination of the concentrations and specific activities of tritium and C{sup 14} is presented as a function of the changing chemical composition of the chimney gas and as a function of time. The effects of radiochemical exchange reactions, together with the tritium isotope effect, are demonstrated. Following this shut-in period, a series of production and flushing tests was conducted. During these experiments, the chimney gas composition was seen to change about as would be expected due to dilution of the chimney gas with formation gas. An examination of radionuclide concentrations and specific activities during the production tests demonstrated the relative unimportance of isotopic exchange and chemical reactions during this period, as compared to the early shut-in periods. Within the limitations of the Gasbuggy experience a generalized model of the behavior of tritium and C{sup 14} can be deduced. The discussion involves estimation of initial distribution of activities, the effects of chemical reactions and isotopic exchange on this distribution, and the importance of the environment in determining the level of radioactivity contamination to be expected. (author)

Today's gas glut and yesterday's contracts: the British Gas predicament

International Nuclear Information System (INIS)

Stoppard, M.

1996-10-01

Deregulation of the gas and electricity industries has led to a state of pronounced oversupply in the UK gas market. The effects of this oversupply became apparent during the course of 1995 and took two forms. Firstly, there was the emergence of a market for the short-term trading of gas. The price levels in this market collapsed in the first half of 1995 opening up a price gap between ''spot'' and contract gas. Secondly, some contract gas was paid for but was not produced, so that delivery to market was indefinitely postponed: there was a run-up in inventory - or ''take-or-pay'' - gas levels, as a form of keeping supply off the market. Oversupply has exerted great pressure on a number of market participants throughout the gas chain who remain locked into purchase agreements for volumes which have no market outlet, and at prices above market levels. The rally in spot price levels experienced since the second quarter of 1996 has eased pressure within the market but has not removed the fundamental strains. The market is expected to remain in oversupply at least up to the end of 1998. Keen price competition may not clear the market even at discount prices, so that shut-in of production capacity is likely. The consequent build-up in take-or-pay levels will continue through the period, although at steadily declining rates, and there is little scope prior to 1999 for the industry as a whole to offload this inventory gas on the market. (author)

Means and method for controlling the neutron output of a neutron generator tube

International Nuclear Information System (INIS)

1980-01-01

A specification is given for an energizing and regulating circuit for a gas filled neutron generator tube consisting of a target, an ion source and a replenisher, the circuit consisting of a power supply to provide a negative high voltage to the target and a target current corresponding to the neutron output of the tube, a constant current source, and control means connected to the power supply and to the constant current source, the control means being responsive to the target current to provide a portion of the constant current to the replenisher substantially to regulate the neutron output of the tube. (author)

Exploring the economic consequences of letting a supplier hold reserve storage

DEFF Research Database (Denmark)

Abginehchi, Soheil; Larsen, Christian; Thorstenson, Anders

2015-01-01

We consider a single-item, periodic review inventory control problem with discrete non-stationary stochastic demand. The time horizon is finite and all shortages at the downstream level are backordered. There are two modes of supply: a normal supplier and a reserve storage supply. The reserve...... storage is capacitated and the downstream buyer can only order the entire inventory in the reserve storage or nothing. If the reserve storage is empty, it takes a fixed time interval before it is replenished again. Provided that the reserve storage is fully replenished it can be used at any time period...

New methodology for aquifer influx status classification for single wells in a gas reservoir with aquifer support

Directory of Open Access Journals (Sweden)

Yong Li

2016-10-01

Full Text Available For gas reservoirs with strong bottom or edge aquifer support, the most important thing is avoiding aquifer breakthrough in a gas well. Water production in gas wells does not only result in processing problems in surface facilities, but it also explicitly reduces well productivity and reservoir recovery. There are a lot of studies on the prediction of water breakthrough time, but they are not completely practicable due to reservoir heterogeneity. This paper provides a new method together with three diagnostic curves to identify aquifer influx status for single gas wells; the aforementioned curves are based on well production and pressure data. The whole production period of a gas well can be classified into three periods based on the diagnostic curves: no aquifer influx period, early aquifer influx period, and middle-late aquifer influx period. This new method has been used for actual gas well analysis to accurately identify gas well aquifer influx status and the water breakthrough sequence of all wells in the same gas field. Additionally, the evaluation results are significantly beneficial for well production rate optimization and development of an effective gas field.

Validated Predictions of Metabolic Energy Consumption for Submaximal Effort Movement

OpenAIRE

Tsianos, George A.; MacFadden, Lisa N.

2016-01-01

Author Summary Muscles consume metabolic energy to generate movement. Performing a movement over a long period of time or at a high intensity strains the respiratory and cardiovascular systems that need to replenish the energy reserves in muscle. Furthermore, consuming and replenishing metabolic energy involves biochemical reactions with byproducts that cause muscle fatigue. These biochemical reactions also produce heat that increases body temperature, potentially causing central fatigue. A m...

A randomized clinical trial in vitamin D-deficient adults comparing replenishment with oral vitamin D3 with narrow-band UV type B light: effects on cholesterol and the transcriptional profiles of skin and blood.

Science.gov (United States)

Ponda, Manish P; Liang, Yupu; Kim, Jaehwan; Hutt, Richard; Dowd, Kathleen; Gilleaudeau, Patricia; Sullivan-Whalen, Mary M; Rodrick, Tori; Kim, Dong Joo; Barash, Irina; Lowes, Michelle A; Breslow, Jan L

2017-05-01

Background: Vitamin D deficiency, defined as a serum 25-hydroxyvitamin D [25(OH)D] concentration light. Objective: We tested the hypothesis that, in vitamin D-deficient adults, the replenishment of vitamin D with UVB exposure would lower LDL-cholesterol concentrations compared with the effect of oral vitamin D 3 supplementation. Design: We performed a randomized clinical trial in vitamin D-deficient adults and compared vitamin D replenishment between subjects who received oral vitamin D 3 ( n = 60) and those who received narrow-band UVB exposure ( n = 58) ≤6 mo. Results: There was no difference in the change from baseline LDL-cholesterol concentrations between oral vitamin D 3 and UVB groups (difference in median of oral vitamin D 3 minus that of UVB: 1.5 mg/dL; 95% CI: -5.0, 7.0 mg/dL). There were also no differences within groups or between groups for changes in total or HDL cholesterol or triglycerides. Transcriptional profiling of skin and blood, however, revealed significant upregulation of immune pathway signaling with oral vitamin D 3 but significant downregulation with UVB. Conclusions: Correcting vitamin D deficiency with either oral vitamin D 3 or UVB does not improve the lipid profile. Beyond cholesterol, these 2 modalities of raising 25(OH)D have disparate effects on gene transcription. This trial was registered at clinicaltrials.gov as NCT01688102. © 2017 American Society for Nutrition.

NATURAL GAS - A CHANCE FOR SUSTAINABLE DEVELOPMENT OF SERBIAN ENERGY SECTOR

Energy Technology Data Exchange (ETDEWEB)

Krstic, S.; Djajic, N.; Kukobat, M.

2007-07-01

Republic Serbia has produced and consumed natural gas domestically since 1952, but has always been net importer. Strategy of Energy Development in Serbia and, especially, National Action Plan for the Gasification on the Territory of Republic of Serbia dedicated special attention to gas economy development in respect with expected contribution in efficient energy use and environmental policy protection in our country. Option of expanded share of natural gas in fulfilling energy requirements in future is reasonable, considering natural gas with its energetic, ecological and economical characteristics as very suitable fuel. Also, in mid-term and most probably in long-term period, the gas import is expected to be more advantageous than oil import. The paper deals the basic features of natural gas consumption in Serbia in nineties and analyses the further development in gas sector for next period until 2015 based on strategic analyses. (auth)

Periodicity in the BrO∕SO2 molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Directory of Open Access Journals (Sweden)

F. Dinger

2018-03-01

Full Text Available We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador for BrO∕SO2 molar ratios. The BrO∕SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua suggest a possible link between a drop in BrO∕SO2 and a future explosion. In addition, the observed relatively high BrO∕SO2 molar ratios after December 2015 imply that bromine degassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on volcanic gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO∕SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO∕SO2 molar ratios with the north–south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO∕SO2 molar

Natural gas utilization in Santa Cruz thermal-electric power; A utilizacao de gas natural em Santa Cruz

Energy Technology Data Exchange (ETDEWEB)

Azevedo, Mauricio F. de.; Lundeqvist, Carl G; Gomes, Gerson; Almeida, A E

1994-12-31

Use of natural gas as an alternative energy source on the thermo electric power plant of Santa Cruz are presented. Economic studies on hydroelectric power plants to use thermal generators during low water supply periods, costs of natural gas as a alternative energy fuel, and the engineer services to the conversion of fuel oil system, are discussed. 5 figs., 6 tabs.

CLATHRATE HYDRATES FORMATION IN SHORT-PERIOD COMETS

International Nuclear Information System (INIS)

Marboeuf, Ulysse; Mousis, Olivier; Petit, Jean-Marc; Schmitt, Bernard

2010-01-01

The initial composition of current models of cometary nuclei is only based on two forms of ice: crystalline ice for long-period comets and amorphous ice for short-period comets. A third form of ice, i.e., clathrate hydrate, could exist within the short-period cometary nuclei, but the area of formation of this crystalline structure in these objects has never been studied. Here, we show that the thermodynamic conditions in the interior of short-period comets allow the existence of clathrate hydrates in Halley-type comets. We show that their existence is viable in the Jupiter family comets only when the equilibrium pressure of CO clathrate hydrate is at least 1 order of magnitude lower than the usually assumed theoretical value. We calculate that the amount of volatiles that could be trapped in the clathrate hydrate layer may be orders of magnitude greater than the daily amount of gas released at the surface of the nucleus at perihelion. The formation and the destruction of the clathrate hydrate cages could then explain the diversity of composition of volatiles observed in comets, as well as some pre-perihelion outbursts. We finally show that the potential clathrate hydrate layer in comet 67P/Churyumov-Gerasimenko would, unfortunately, be deep inside the nucleus, out of reach of the Rosetta lander. However, such a clathrate hydrate layer would show up by the gas composition of the coma.

Welfare effects of unbundling gas storage and distribution

International Nuclear Information System (INIS)

Breton, M.; Montreal Univ., PQ; Kharbach, M.

2006-01-01

The creation of inventories and stockpiles can help to reduce price and production fluctuations. This paper presented the results of a simulation of market architectures using a 2 period model. The aim of the paper was to provide insights on the merits of a gas unbundling policy recently adopted in many gas markets. In terms of market architecture, it was first assumed that one of the gas firms owned the storage facility and was mandated to give a second firm access to it. It was then assumed that an independent third firm was responsible for the storage activity so that the other 2 firms competed in the downstream gas market and bought storage services from the independent firm. High and low price periods in a single year were considered. The first architecture assumed an Open Access framework which introduced a Stackelberg competition component in the downstream market through the storage participation in the final goods offering. The second architecture assumed an independent storage activity, and a Cournot component was present. Seasonal storage facilities were filled during the low price period and emptied during the high price period. Results of the simulation indicated that total welfare and consumer welfare were maximized in the case of the integrated firm owning the storage facilities and operating in the downstream market. Success was attributed to the Open Access framework and the Stackelberg competition component in the downstream market. The bundled architecture led to higher consumer surplus than the unbundled architecture. It was concluded that regulatory reforms in North American and European gas sectors that foster separating storage and merchant activities can not be justified based on welfare arguments. 12 refs., 1 tab

Natural gas in Mexico

International Nuclear Information System (INIS)

Ramirez, M.

1999-01-01

A series of overhead viewgraphs accompanied this presentation which focused on various aspects of the natural gas industry in Mexico. Some of the viewgraphs depicted statistics from 1998 regarding natural gas throughput from various companies in North America, natural gas reserves around the world, and natural gas reserves in Mexico. Other viewgraphs depicted associated and non-associated natural gas production from 1988 to 1998 in million cubic feet per day. The Burgos Basin and the Cantarell Basin gas production from 1997 to 2004 was also depicted. Other viewgraphs were entitled: (1) gas processing infrastructure for 1999, (2) cryogenic plant at Cd. PEMEX, (3) average annual growth of dry natural gas production for 1997-2004 is estimated at 5.2 per cent, (4) gas flows for December 1998, (5) PGPB- interconnect points, (6) U.S. Mexico gas trade for 1994-1998, (7) PGPB's interconnect projects with U.S., and (8) natural gas storage areas. Technological innovations in the industry include more efficient gas turbines which allow for cogeneration, heat recovery steam generators which reduce pollutant emissions by 21 per cent, cold boxes which increase heat transfer efficiency, and lateral reboilers which reduce energy consumption and total costs. A pie chart depicting natural gas demand by sector shows that natural gas for power generation will increase from 16 per cent in 1997 to 31 per cent in 2004. The opportunities for cogeneration projects were also reviewed. The Comision Federal de Electricidad and independent power producers represent the largest opportunity. The 1997-2001 investment program proposes an 85 per cent sulphur dioxide emission reduction compared to 1997 levels. This presentation also noted that during the 1998-2001 period, total ethane production will grow by 58 tbd. 31 figs

Accounting for fuel price risk when comparing renewable to gas-fired generation: the role of forward natural gas prices

International Nuclear Information System (INIS)

Bolinger, Mark; Wiser, Ryan; Golove, William

2006-01-01

Unlike natural gas-fired generation, renewable generation (e.g., from wind, solar, and geothermal power) is largely immune to fuel price risk. If ratepayers are rational and value long-term price stability, then-contrary to common practice-any comparison of the levelized cost of renewable to gas-fired generation should be based on a hedged gas price input, rather than an uncertain gas price forecast. This paper compares natural gas prices that can be locked in through futures, swaps, and physical supply contracts to contemporaneous long-term forecasts of spot gas prices. We find that from 2000 to 2003, forward gas prices for terms of 2-10 years have been considerably higher than most contemporaneous long-term gas price forecasts. This difference is striking, and implies that comparisons between renewable and gas-fired generation based on these forecasts over this period have arguably yielded results that are biased in favor of gas-fired generation

Stagnations of increasing trends in negative pressure with repeated cavitation in water/metal Berthelot tubes as a result of mechanical sealing

International Nuclear Information System (INIS)

Hiro, Kazuki; Ohde, Yoshihito; Tanzawa, Yasutoshi

2003-01-01

To investigate effects of mechanical sealing on negative pressures in water/metal tube Berthelot systems, trends in negative pressure are observed through runs of temperature cycles below 90 deg. C in two systems made of metals having small amounts of gas inclusions. The first system is a pre-degassed all-stainless-steel tube/plug system. The steel is a special product for vacuum engineering. The second is the same tube sealed with plugs made of silver solidified one-dimensionally in a vacuum furnace. A new type of trend, stagnation for intermediate cycles is found in both systems so long as sealing distortion of each plug is small in amount. The stagnation period for the first system is longer than that for the second one. A metallurgical mechanism of a gas-being-replenished crevice model is proposed: distorted parts of metals undergo heat-treatment during runs of temperature cycles, and the heat-treatment enhances the rates of impurity gas transports to crevices on the metal surface where cavitation occurs, and the transport causes the stagnation for cycles during which the rates are still high

Bench-Scale Demonstration of Hot-Gas Desulfurization Technology

International Nuclear Information System (INIS)

Portzer, Jeffrey W.; Gangwal, Santosh K.

1997-01-01

Prior to the current project, development of the DSRP was done in a laboratory setting, using synthetic gas mixtures to simulate the regeneration off-gas and coal gas feeds. The objective of the current work is to further the development of zinc titanate fluidized-bed desulfurization (ZTFBD) and the DSRP for hot-gas cleanup by testing with actual coal gas. The objectives of this project are to: (1) Develop and test an integrated, skid-mounted, bench-scale ZTFBD/DSRP reactor system with a slipstream of actual coal gas; (2) Test the bench-scale DSRP over an extended period with a slipstream of actual coal gas to quantify the degradation in performance, if any, caused by the trace contaminants present in coal gas (including heavy metals, chlorides, fluorides, and ammonia); (3) Expose the DSRP catalyst to actual coal gas for extended periods and then test its activity in a laboratory reactor to quantify the degradation in performance, if any, caused by static exposure to the trace contaminants in coal gas; (4) Design and fabricate a six-fold larger-scale DSRP reactor system for future slipstream testing; (5) Further develop the fluidized-bed DSRP to handle high concentrations (up to 14 percent) of SO 2 that are likely to be encountered when pure air is used for regeneration of desulfurization sorbents; and (6) Conduct extended field testing of the 6X DSRP reactor with actual coal gas and high concentrations of SO 2 . The accomplishment of the first three objectives--testing the DSRP with actual coal gas, integration with hot-gas desulfurization, and catalyst exposure testing--was described previously (Portzer and Gangwal, 1994, 1995; Portzer et al., 1996). This paper summarizes the results of previous work and describes the current activities and plans to accomplish the remaining objectives

Formation and removal of dioxins in a MSWI during different operating periods

Energy Technology Data Exchange (ETDEWEB)

Wang, H.C.; Hwang, J.F. [Center for Environmental, Safety, and Health Technology, Industrial Technology Research Institute, Hsin-Chu (Taiwan). Environmental Health and Air Pollution Division; Chang, M.B.; Chi, K.H. [National Central University, Chungli (Taiwan). Graduate Inst. of Environmental Engineering

2004-09-15

There was little literature to report the dioxin emission concentrations and characteristics during start-up and burndown periods. This research aims to establish the databases of dioxin concentrations in the flue gas and evaluate the dioxin removal efficiencies by air pollution control devices (APCDs) at different operating periods (during start-up, normal operating and burn down periods).

GAS STORAGE TECHNOLOGY CONSORTIUM

Energy Technology Data Exchange (ETDEWEB)

Robert W. Watson

2004-10-18

Gas storage is a critical element in the natural gas industry. Producers, transmission and distribution companies, marketers, and end users all benefit directly from the load balancing function of storage. The unbundling process has fundamentally changed the way storage is used and valued. As an unbundled service, the value of storage is being recovered at rates that reflect its value. Moreover, the marketplace has differentiated between various types of storage services, and has increasingly rewarded flexibility, safety, and reliability. The size of the natural gas market has increased and is projected to continue to increase towards 30 trillion cubic feet (TCF) over the next 10 to 15 years. Much of this increase is projected to come from electric generation, particularly peaking units. Gas storage, particularly the flexible services that are most suited to electric loads, is critical in meeting the needs of these new markets. In order to address the gas storage needs of the natural gas industry, an industry-driven consortium was created--the Gas Storage Technology Consortium (GSTC). The objective of the GSTC is to provide a means to accomplish industry-driven research and development designed to enhance operational flexibility and deliverability of the Nation's gas storage system, and provide a cost effective, safe, and reliable supply of natural gas to meet domestic demand. To accomplish this objective, the project is divided into three phases that are managed and directed by the GSTC Coordinator. The first phase, Phase 1A, was initiated on September 30, 2003, and was completed on March 31, 2004. Phase 1A of the project included the creation of the GSTC structure, development and refinement of a technical approach (work plan) for deliverability enhancement and reservoir management. This report deals with Phase 1B and encompasses the period July 1, 2004, through September 30, 2004. During this time period there were three main activities. First was the

Morphology of Gas Release in Physical Simulants

Energy Technology Data Exchange (ETDEWEB)

Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

2014-07-03

This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

Large scale modulation of high frequency acoustic waves in periodic porous media.

Science.gov (United States)

Boutin, Claude; Rallu, Antoine; Hans, Stephane

2012-12-01

This paper deals with the description of the modulation at large scale of high frequency acoustic waves in gas saturated periodic porous media. High frequencies mean local dynamics at the pore scale and therefore absence of scale separation in the usual sense of homogenization. However, although the pressure is spatially varying in the pores (according to periodic eigenmodes), the mode amplitude can present a large scale modulation, thereby introducing another type of scale separation to which the asymptotic multi-scale procedure applies. The approach is first presented on a periodic network of inter-connected Helmholtz resonators. The equations governing the modulations carried by periodic eigenmodes, at frequencies close to their eigenfrequency, are derived. The number of cells on which the carrying periodic mode is defined is therefore a parameter of the modeling. In a second part, the asymptotic approach is developed for periodic porous media saturated by a perfect gas. Using the "multicells" periodic condition, one obtains the family of equations governing the amplitude modulation at large scale of high frequency waves. The significant difference between modulations of simple and multiple mode are evidenced and discussed. The features of the modulation (anisotropy, width of frequency band) are also analyzed.

Gas fueling system for SST-1

International Nuclear Information System (INIS)

Dhanani, Kalpeshkumar R.; Khan, Ziauddin; Raval, Dilip; Semwal, Pratibha; George, Siju; Paravastu, Yuvakiran; Thankey, Prashant; Khan, Mohammad Shoaib; Pradhan, Subrata

2015-01-01

SST-1 Tokamak, the first Indian Steady-state Superconducting experimental device is at present under operation in Institute for Plasma Research. For plasma break down and initiation, the piezoelectric valve based gas feed system is implemented as primary requirement due to its precise control, easy handling, low costs for both construction and maintenance and its flexibility in working gas selection. The main functions of SST-1 gas feed system are to feed the required amount of ultrahigh purity hydrogen gas for specified period into the vessel during plasma operation and ultrahigh helium gas for glow discharge cleaning. In addition to these facilities, the gas feed system is used to feed a mixture gas of hydrogen and helium as well as other gases like nitrogen and Argon during divertor cooling etc. The piezoelectric valves used in SST-1 are remotely driven by a PXI based platform and are calibrated before the plasma operation during each SST-1 plasma operation with precise control. This paper will present the technical development and the results of gas fueling in SST-1. (author)

On jointly optimising the changes of seasonable goods and inventory replenishment

Science.gov (United States)

Li, Zhaolin; Tao, Feng; Sun, Daewon

2012-06-01

Retailers often need to replace soon-to-be-unseasonable products with new seasonable goods when the season changes. The trade-off for such activities involves choosing between the salvage loss of the unseasonable product and the profit of selling the seasonable product early. This article develops a periodic-review inventory model for planning the changes of seasonable goods with state-dependent demand and cost parameters. We show that the single-period optimal policy for product changes is a threshold policy based on the initial inventory of the unseasonable goods. The corresponding optimal inventory policy follows a Purchase-Keep-Dispose policy if the incumbent product is kept or a base-stock policy if the incumbent product is replaced. Numerically, we find that the structure of the multi-period optimal policy resembles that of the single-period model. We propose a heuristic to solve the multi-period model and demonstrate its effectiveness. Our research provides insights into dynamically managing seasonable goods.

Liberalization of Russian gas exports: benefits and challenges

Directory of Open Access Journals (Sweden)

Yakunina Alla

2017-01-01

Full Text Available Russian gas export liberalization has been discussed throughout the post-Soviet period. Recently, the number of Gazprom’s export monopoly advocates has been diminishing as a result of dramatic changes in both European and Russian gas markets, which are: increasing international trade in liquefied natural gas; the EU movement from long-term contracts to the commodity markets and hub pricing; substantially increased share of the non-Gazprom gas suppliers at the Russian domestic market. Although there is a potential risk of price decrease in the EU gas market in the case of the Gazprom export monopoly abolition, the benefits of the Russian gas export liberalization would be greater than losses. The gas resource base and the cost of pipeline gas production would allow Russia to improve its positions in the world market.

Method for filtering radon from a gas system

International Nuclear Information System (INIS)

Sowinski, R.F.

1992-01-01

This patent describes a method of filtering, adjacent to an end user-customer's residence, or business in which at least a single gas appliance is located, a natural gas stream in which benz-a-anthracene has been concentrated at sufficient levels to be a health threat in a natural gas gathering and distributing network. It comprises introducing the natural gas stream to a filter selected from a group that includes impingement, passing the filtered natural gas stream to the customer's gas appliance wherein safe use of the energy associated with the stream occurs, periodically and safely removing the filter for disposing of captured benz-a-anthracene, inserting a new filter in place of the removed filter of step

Network design for cylinder gas distribution

Directory of Open Access Journals (Sweden)

Tejinder Pal Singh

2015-01-01

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

Rising natural gas prices : impacts on U.S. industries

International Nuclear Information System (INIS)

Henry, D.

2005-01-01

The impact of rising natural gas prices on the United States economy and domestic industries was examined in this PowerPoint presentation. Industry comments were solicited on the effects of natural gas prices on their business performance from 2000 to 2004 in order to collect data, and macroeconomic impacts were determined through the use of an inter-industry model. Results of the survey and subsequent model suggested that in 2000 and 2001, real gross domestic product (GDP) growth was depressed by 0.2 per cent because of higher natural gas prices. Between 2000 and 2004, the civilian workforce was lower by 489,000 jobs. It was determined that nitrogenous fertilizer manufacturing was the most gas intensive industry. The results indicated that higher natural gas prices were an additional burden on manufacturing industries, and that the economic performance of natural gas intensive industries was poor between 2000-2004. However, it was just as poor between 1997-2000, when gas prices were relatively low and stable. Natural gas intensive industries passed along price increases in their products to their downstream consumers. Despite job losses, wages in natural gas intensive industries were higher and grew faster than in the rest of the manufacturing industry in the 2000-2004 period. Although capital expenditures declined between 2000 to 2004, they declined more rapidly in the 1997-2000 period. There has been no evidence of a decline in international competitiveness of natural gas intensive industries. It was concluded that rising natural gas prices have had a significant impact on the growth of the economy and workforce. tabs., figs

Policy Uncertainty, Investment and Commitment Periods

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

Today's investment decisions in key sectors such as energy, forestry or transport have significant impacts on the levels of greenhouse gas (GHG) emissions over the coming decades. Given the economic and environmental long-term implications of capital investment and retirement, a climate mitigation regime should aim to encourage capital investment in climate-friendly technologies. Many factors affect technology choice and the timing of investment, including investor expectations about future prices and policies. Recent international discussions have focused on the importance of providing more certainty about future climate policy stringency. The design of commitment periods can play a role in creating this environment. This paper assesses how the length of commitment periods influences policy uncertainty and investment decisions. In particular, the paper analyses the relationship between commitment period length and near term investment decisions in climate friendly technology.

On-Board Hydrogen Gas Production System For Stirling Engines

Science.gov (United States)

Johansson, Lennart N.

2004-06-29

A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed. A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed.

Technical development in the city gas business

Energy Technology Data Exchange (ETDEWEB)

Kondo, Takehiko

1988-07-01

This paper reports on technical developments in the city gas business. Energy demand is expected to increase by only 1.3 over the 1986 to 1995 period. Also, the importance of complex energy is increasing. As a result, limited demand entails more violent competition among various energy industries (electricity, gas, oil, etc.). Such trend is calling for a new system that flexibly meets the needs of the present society. Household-purpose city gas accounts for more than 90% of all the city gas. One of the means to increase city gas demand is to encourage people to use gas-type room heating/cooling systems to enrich citizen life and ease difficulties during the power-consumption peak period. Anothe important factor is to develop a system, such as a cogeneration system, that flexibly applies to heat and electricity balance. Pipeline construction and maintenance costs account for most of the gas-related costs. One of the attempts to reduce such costs is the development of a small-section or non-digging pipe-laying technique and a diagnostic robot. Large computers are already in use in total information management. To ensure security, people concerned have made much progress in upgrading the performance of and spreading sensors for carbon monoxide and other gases. To eliminate all accidents, they have also developed an automatic cut-off method in case of an abnormal efflux. This method is expected to spread in the future. They have also developed an LNG cold heat utilization technique and a by-product carbon fiber. (2 figs)

Modern problems of relaxation gas dynamics

International Nuclear Information System (INIS)

Losev, S.A.; Osipov, A.I.

1985-01-01

Some of the dynamical characteristics of relaxation processes are studied. Unfortunately, many dynamical characteristics of relaxation processes, necessary for the solution of important scientific and applied problems, are not known. These problems require further development of experimental methods of the study of nonequilibrium gas. It is known, that gas systems are shifted from the equilibrium by different methods: by acoustic and shock wav es, by means of gas expansion in nozzles and jets, by powerful radiations (laser, first of all), by electric discharges, in burning and combustion devices, etc. Non-equilibrium gas is produced in installations of continuum, impulse and periodic regime. Molecular beams, shock tubes (especially with nozzles), flow and jet installations, aerodynamical tubes, plasmatrons, vessels with a gas, influenced by the strong radiation, burners and combustion devices, where the study of non-euilibrium gas is helpful to solve the problems of the determination of kinetic equations and constants of physico-chemical kinetics

Common issues concerning electric power and gas

International Nuclear Information System (INIS)

1996-01-01

EDF and GDF, the French government owned electric power and gas utilities have jointly decided to improve their employment and employee situation with the hiring of 11000 to 15000 young people for a 3-year period and the reduction of the working hours. A european disagreement is to be judged concerning electric power and gas import and export monopolies in several european countries

Long-term outlook for world gas trade: 1920-2015

International Nuclear Information System (INIS)

MacDougall, M.W.; Linder, P.T.

1992-01-01

The World Gas Trade Model (WGTM) was designed to simulate the economic relationships of world and regional gas markets. Using the data gathered for supply, transportation and demand, the model calculated a consistent set of prices and quantities that, through time, would simultaneously satisfy all physical, behavioural and financial relations embodied in the model network. Three sensitivity cases were examined. The first one examined the effects on world gas supply, demand and trade with oil prices remaining constant throughout the study period. The second sensitivity case examined the effects of lower costs of new liquefied natural gas (LNG) liquefaction facilities. The third sensitivity case examined the effects of policy shifts in favour of natural gas over other fossil fuels for environmental reasons. During the 25-year period of the study, global production of natural gas was projected to almost double, with the overall level of final consumption being very similar to production. Results indicated that natural gas would remain predominantly a regionally traded commodity. The relatively high cost of natural gas transportation was shown to provide a substantial competitive advantage to local producers compared to more distant competitors. The cost of new liquefaction facilities was not considered to be competitive with long distance pipeline transportation. The model also indicated that reducing transportation costs or increasing the wellhead price differential between exporting and importing regions would accelerate the development of global natural gas trade. figs., tabs., refs

Gas microstrip detectors for X-ray tomographic flow imaging

CERN Document Server

Key, M J; Luggar, R D; Kundu, A

2003-01-01

A investigation into the suitability of gas microstrip detector technology for a high-speed industrial X-ray tomography system is reported. X-ray energies in the region 20-30 keV are well suited to the application, which involves imaging two-dimensional slices through gas/liquid multiphase pipeline flows for quantitative component fraction measurement. Stable operation over a period representing several hundred individual tomographic scans at gas gains of 500 is demonstrated using a Penning gas mixture of krypton/propylene.

Pressure in the natural gas pipe. Coherence between tariffs for natural gas transport, and congestion in the Netherlands

International Nuclear Information System (INIS)

Boots, M.G.; De Joode, J.; Lise, W.

2005-11-01

Using GASTALE (Gas mArket System for Trade Analysis in a Liberalizing Europe), a comprehensive computational game theoretic model of the European gas market, the Energy research Centre of the Netherlands (ECN) conducted at the request of Gas Transportation Services (GTS) a study on the relationship between gas transport tariffs, the demand for gas transport and possible re-routing of gas flows in Northwestern Europe. We find that lowering the average Dutch transport tariff compared to the average German transport tariff induces a re-routing of gas flows from the German network to the Dutch network. In periods of high gas demand, such as the peak winter season, the lower transport tariffs lead to a high potential demand for gas transport which cannot be fulfilled by the limited capacity of the Dutch gas transport network. This will probably even lead to congestion in the Dutch network as a 'first-come first-served' regime is currently applied in the Netherlands. So Dutch gas transport tariffs being out of line with the gas transport tariffs neighbouring countries, implies that there is a real chance that transit flows are crowding-out gas flows destined for Dutch final consumers of gas. Hence, the security of gas supply for the Netherlands is seriously threatened. These findings are robust for variations in the model assumptions as shown by a number of sensitivity analyses [nl

Natural gas market assessment. Canadian natural gas market mechanisms: Recent experiences and developments

International Nuclear Information System (INIS)

1993-11-01

The increase in natural gas demand and the associated expansions of most of the pipeline systems serving western Canada have reduced the excess deliverability or excess productive capacity that existed at the time of deregulation of the natural gas industry in 1985. Based on an industry survey, the responses of natural gas buyers and sellers to recent supply difficulties are described. Specific production, transportation, and contractual difficulties were encountered in winter 1992/93 as production was stretched to meet record levels of demand during periods of very cold temperatures and as short-term spot prices reached very high levels. Problems at this time included wellhead freezeups, pipeline outages, and inadequate contract terms and conditions. Methods used to maintain gas flows to end users are reviewed, including a discussion of force majeure, spot gas purchases, storage, supply curtailment, and special loan arrangements. In 1992/93, in most instances where the responsibility fell on the end-user to solve the supply problem, the difficulty was shifted to local distribution companies who have traditionally had more experience with such situations. No cases were identified where either a firm or interruptible end-user was forced to curtail gas consumption because of inadequate supply. New market mechanisms are emerging that will enable buyers and sellers of western Canadian gas to avoid many of the problems encountered in 1992/93. These include prearranged backstopping arrangements, short-term spot markets, access to other gas basins, standardized gas contracts, electronic trading, and price risk management tools. 11 figs

Implications of shale gas exploitation for UK climate change targets under a production-based accounting system.

Science.gov (United States)

Turk, J.; Reay, D.; Haszeldine, S.

2017-12-01

The shale gas boom in the USA has seemingly decreased the greenhouse gas intensity of electricity generation in the USA over the last decade. The United Kingdom is supporting its own shale gas industry to increase its own domestic energy supply. The UK's climate change policy is underpinned by defined national carbon budgets periods. The UK has met Carbon Budget 1 (2008 - 2012) and is likely to meet the second and third carbon budgets (2013 - 2022). There is a projected shortcoming in the fourth carbon budget (2023 - 2027). This shortfall may be increased as the UK pursues a domestic shale gas industry. Under the current production-based GHG accounting system, the UK is incentivized to import natural gas rather than produce it domestically. If the projected gas supply were to be met by UK shale gas, we project additional greenhouse gas emissions which would need to be accommodated during Carbon Budget periods 3 - 6. Additionally, natural gas electricity generation will contribute to sustaining grid electricity emissions during the same time period within the traded European Union emissions cap.

Oil and gas -94

International Nuclear Information System (INIS)

Bauer, A.

1994-06-01

This report deals with the use of oil-, natural gas and liquefied petroleum gas (LPG) during 1993. Information about markets and technical environmental questions are also given. Data have been collected from earlier reports, information given by different persons and statistics from SCB and SPI. The import of crude oil increased from 16,8 million tons in 1992 to 17,8 million tons in 1993. The import of oil products decreased by 0,9 million tons down to 6,7 million tons in the same period. During this period, the import of natural gas increased by 9%, a total of 817 million cubic meters. The import of LPG was 748000 tons in 1993, which is 61000 tons less compared to the import of 1992. The production in Sweden for 1993 was 290000 tons, the same level as the level reached in 1992. The export of LPG increased from 107000 tons to 138000 tons during this period. In January 1993, legislative changes were made concerning energy taxes and carbon dioxide penalty taxes. The rate of the latter was increased from 25 to 32 oere per kilogram of carbon dioxide released in the atmosphere. For industry and greenhouse production, the penalty rate is only 25% or 8 oere per kilogram of carbon dioxide. From 1995 to 1998, yearly increases in the rate of energy taxes and carbon dioxide penalty taxes will be based on the consumer price index. Taxes will be increased by 4% in 1994. Due to changes in energy taxes, the consumption of LPG decreased in 1993. Earlier, many industries had changed from oil to LPG but now have changed back to oil. 8 figs, 17 tabs

Physical simulation of gas reservoir formation in the Liwan 3-1 deep-water gas field in the Baiyun sag, Pearl River Mouth Basin

Directory of Open Access Journals (Sweden)

Gang Gao

2015-01-01

Full Text Available To figure out the process and controlling factors of gas reservoir formation in deep-waters, based on an analysis of geological features, source of natural gas and process of reservoir formation in the Liwan 3-1 gas field, physical simulation experiment of the gas reservoir formation process has been performed, consequently, pattern and features of gas reservoir formation in the Baiyun sag has been found out. The results of the experiment show that: ① the formation of the Liwan 3-1 faulted anticline gas field is closely related to the longstanding active large faults, where natural gas is composed of a high proportion of hydrocarbons, a small amount of non-hydrocarbons, and the wet gas generated during highly mature stage shows obvious vertical migration signs; ② liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping & Zhuhai Formation, whereas natural gas comes mainly from source rock of the Enping Formation, and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well; ③ although there was gas migration and accumulation, yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period; later as fault activity gradually weakened, gas started to accumulate into reservoirs in the Baiyun sag; ④ there is stronger vertical migration of oil and gas than lateral migration, and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation; ⑤ effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag; ⑥ the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen, the more likely gas may accumulate in the trap in late stage, therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source

Review of Current Literature and Research on Gas Supersaturation and Gas Bubble Trauma: Special Publication Number 1, 1986.

Energy Technology Data Exchange (ETDEWEB)

Colt, John; Bouck, Gerald R.; Fidler, Larry

1986-12-01

This report presents recently published information and on-going research on the various areas of gas supersaturation. Growing interest in the effects of chronic gas supersaturation on aquatic animals has been due primarily to heavy mortality of salmonid species under hatchery conditions. Extensive examination of affected animals has failed to consistently identify pathogenic organisms. Water quality sampling has shown that chronic levels of gas supersaturation are commonly present during a significant period of the year. Small marine fish larvae are significantly more sensitive to gas supersaturation than salmonids. Present water quality criteria for gas supersaturation are not adequate for the protection of either salmonids under chronic exposure or marine fish larvae, especially in aquaria or hatcheries. To increase communication between interested parties in the field of gas supersaturation research and control, addresses and telephone numbers of all people responding to the questionnaire are included. 102 refs.

A decision analysis approach to climate adaptation: comparing multiple pathways for multi-decadal decision making

Science.gov (United States)

Lin, B. B.; Little, L.

2013-12-01

Policy planners around the world are required to consider the implications of adapting to climatic change across spatial contexts and decadal timeframes. However, local level information for planning is often poorly defined, even though climate adaptation decision-making is made at this scale. This is especially true when considering sea level rise and coastal impacts of climate change. We present a simple approach using sea level rise simulations paired with adaptation scenarios to assess a range of adaptation options available to local councils dealing with issues of beach recession under present and future sea level rise and storm surge. Erosion and beach recession pose a large socioeconomic risk to coastal communities because of the loss of key coastal infrastructure. We examine the well-known adaptation technique of beach nourishment and assess various timings and amounts of beach nourishment at decadal time spans in relation to beach recession impacts. The objective was to identify an adaptation strategy that would allow for a low frequency of management interventions, the maintenance of beach width, and the ability to minimize variation in beach width over the 2010 to 2100 simulation period. 1000 replications of each adaptation option were produced against the 90 year simulation in order to model the ability each adaptation option to achieve the three key objectives. Three sets of adaptation scenarios were identified. Within each scenario, a number of adaptation options were tested. The three scenarios were: 1) Fixed periodic beach replenishment of specific amounts at 20 and 50 year intervals, 2) Beach replenishment to the initial beach width based on trigger levels of recession (5m, 10m, 20m), and 3) Fixed period beach replenishment of a variable amount at decadal intervals (every 10, 20, 30, 40, 50 years). For each adaptation option, we show the effectiveness of each beach replenishment scenario to maintain beach width and consider the implications of more

Closed-cycle 1-kHz-pulse-repetition-frequency HF(DF) laser

Science.gov (United States)

Harris, Michael R.; Morris, A. V.; Gorton, Eric K.

1998-05-01

We describe the design and performance of a closed cycle, high pulse repetition frequency HF(DF) laser. A short duration, glow discharge is formed in a 10 SF6:1 H2(D2) gas mixture at a total pressure of approximately 110 torr. A pair of profiled electrodes define a 15 X 0.5 X 0.5 cm3 discharge volume through which gas flow is forced in the direction transverse to the optical axis. A centrifugal fan provides adequate gas flow to enable operation up to 3 kHz repetition frequency. The fan also passes the gas through a scrubber cell in which ground state HF(DF) is eliminated from the gas stream. An automated gas make-up system replenishes the spent fuel gases removed by the scrubber. Total gas admission is regulated by monitoring the system pressure, whilst the correct fuel balance is maintained through measurement of the discharge voltage. The HF(DF) generation rate is determined to be close to 5 X 1019 molecules per second per watt of laser output. Typical mean laser output powers of up to 3 watts can be delivered for extended periods of time. The primary limitation to life is found to be the discharge pre- ionization system. A distributed resistance corona pre- ionizer is shown to be advantageous when compared with an alternative arc array scheme.

DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

International Nuclear Information System (INIS)

Unknown

2002-01-01

The objectives of this report period were to complete the development of the Gas Generator design, which was done; fabricate and test of the non-polluting unique power turbine drive gas Gas Generator, which has been postponed. Focus during this report period has been to complete the brazing and bonding necessary to fabricate the Gas Generator hardware, continue making preparations for fabricating and testing the Gas Generator, and continuing the fabrication of the Gas Generator hardware and ancillary hardware in preparation for the test program. Fabrication is more than 95% complete and is expected to conclude in early May 2002. the test schedule was affected by relocation of the testing to another test supplier. The target test date for hot fire testing is now not earlier than June 15, 2002

High temperature gas cleaning for pressurized gasification. Final report

Energy Technology Data Exchange (ETDEWEB)

Alden, H.; Hagstroem, P.; Hallgren, A.; Waldheim, L. [TPS Termiska Processer AB, Nykoeping (Sweden)

2000-04-01

The purpose of the project was to build an apparatus to study pressurized, high temperature gas cleaning of raw gasification gas generated from biomass. A flexible and easy to operate pressurized apparatus was designed and installed for the investigations in high temperature gas cleaning by means of thermal, catalytic or chemical procedures. A semi continuos fuel feeding concept, at a maximum rate of 700 g/h, allowed a very constant formation of a gas product at 700 deg C. The gas product was subsequently introduced into a fixed bed secondary reactor where the actual gas cleanup or reformation was fulfilled. The installation work was divided into four work periods and apart from a few delays the work was carried out according to the time plan. During the first work period (January - June 1994) the technical design, drawings etc. of the reactor and additional parts were completed. All material for the construction was ordered and the installation work was started. The second work period (July - December 1994) was dedicated to the construction and the installation of the different components. Initial tests with the electrical heating elements, control system and gas supply were assigned to the third work period (January - June 1995). After the commissioning and the resulting modifications, initial pyrolysis and tar decomposition experiments were performed. During the fourth and final work period, (June - December 1995) encouraging results from first tests allowed the experimental part of the project work to commence, however in a slightly reduced program. The experimental part of the project work comparatively studied tar decomposition as a function of the process conditions as well as of the choice of catalyst. Two different catalysts, dolomite and a commercial Ni-based catalyst, were evaluated in the unit. Their tar cracking ability in the pressure interval 1 - 20 bar and at cracker bed temperatures between 800 - 900 deg C was compared. Long term tests to study

Period meter output in response to terminated ramps of reactivity

Energy Technology Data Exchange (ETDEWEB)

Cummins, J D [Dynamics Group, Control and Instrumentation Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1962-07-15

The time behaviour of the period meter output has been determined for a range of total reactivity injections and reactivity rates. Some results which are directly applicable to graphite gas cooled reactors are given. (author)

Can mesophotic reefs replenish shallow reefs? Reduced coral reproductive performance casts a doubt.

Science.gov (United States)

Shlesinger, Tom; Grinblat, Mila; Rapuano, Hanna; Amit, Tal; Loya, Yossi

2018-02-01

Mesophotic coral ecosystems (i.e., deep coral reefs at 30-120 m depth) appear to be thriving while many shallow reefs in the world are declining. Amid efforts to understand and manage their decline, it was suggested that mesophotic reefs might serve as natural refuges and a possible source of propagules for the shallow reefs. However, our knowledge of how reproductive performance of corals alters with depth is sparse. Here, we present a comprehensive study of the reproductive phenology, fecundity, and abundance of seven reef-building conspecific corals in shallow and mesophotic habitats. Significant differences were found in the synchrony and timing of gametogenesis and spawning between shallow and mesophotic coral populations. Thus, mesophotic populations exhibited delayed or protracted spawning events, which led to spawning of the mesophotic colonies in large proportions at times where the shallow ones had long been depleted of reproductive material. All species investigated demonstrated a substantial reduction in fecundity and/or oocyte sizes at mesophotic depths (40-60 m). Two species (Seriatopora hystrix and Galaxea fascicularis) displayed a reduction in both fecundity and oocyte size at mesophotic depths. Turbinaria reniformis had only reduced fecundity and Acropora squarrosa and Acropora valida only reduced oocyte size. In Montipora verrucosa, reduced fecundity was found during one annual reproductive season while, in the following year, only reduced oocyte size was found. In contrast, reduced oocyte size in mesophotic populations of Acropora squarrosa was consistent along three studied years. One species, Acropora pharaonis, was found to be infertile at mesophotic depths along two studied years. This indicates that reproductive performance decreases with depth; and that although some species are capable of reproducing at mesophotic depths, their contribution to the replenishment of shallow reefs may be inconsequential. Reduced reproductive performance

Comprehensive modulation of tumor progression and regression with periodic fasting and refeeding circles via boosting IGFBP-3 loops and NK responses.

Science.gov (United States)

Chen, Xiancheng; Lin, Xiaojuan; Li, Meng

2012-10-01

Progressive tumor-bearing patients deserve to benefit from more realistic approaches. Here, a study revealed the impact of modified periodic fasting and refeeding regimen on tumor progression or regression with little or no loss of food intake and body weight. Human A549 lung, HepG-2 liver, and SKOV-3 ovary progressive tumor-bearing mice were established and subjected to 4 wk of periodic fasting/refeeding cycles (PFRC), including periodic 1-d fasting/6-d refeeding weekly (protocol 1) and periodic 2-d fasting/5-d refeeding weekly (P2DF/5DR, protocol 2), with ad libitum (AL)-fed hosts as controls. Afterwards, PFRC groups exhibited tumor growth arrest with some tendency towards regression; especially, complete regression of progressive tumors and metastases comprised between 43.75 and 56.25% of tumor-challenged hosts in P2DF/5DR group (P fasting/6-d refeeding weekly groups survived a 4-month study period vs. only 31.25-37.5% in AL control group. Immunological assays and Luminex microarray revealed that tumor growth remission is mainly via natural killer cell (NK) reactivity and cross-regulation of IGF-binding protein-3, IGF/IGF-receptor, and megakaryocyte growth and development factor autocrine and paracrine loops. In vivo cellular and humoral assays indicated that tumor-regressive induction by PFRC protocols could be partly terminated by NK cell and IGF-binding protein-3 blockade or replenishment of IGF-I/-II and megakaryocyte growth and development factor. These findings offer a better understanding of comprehensive modulation of periodic fasting/refeeding strategy on the balance between tumor progression and regression.

Natural gas consumption and economic growth: Are we ready to natural gas price liberalization in Iran?

International Nuclear Information System (INIS)

Heidari, Hassan; Katircioglu, Salih Turan; Saeidpour, Lesyan

2013-01-01

This paper examines the relationship between natural gas consumption and economic growth in Iran within a multivariate production model. We also investigate the effects of natural gas price on its consumption and economic growth using a demand side model. The paper employs bounds test approach to level relationship over the period of 1972–007. We find evidence of bidirectional positive relationship between natural gas consumption and economic growth in short-run and long-run, based on the production model. The findings also suggest that real GDP growth and natural gas have positive and negative impacts on gross fixed capital formation, respectively. Employment, however, was found to have negative but insignificant impact on gross fixed capital formation. Moreover, the estimation results of demand side model suggest that natural gas price has negative and significant impact on natural gas consumption only in the long-run, though there is insignificant impact on economic growth. These results imply that the Iranian government's decision for natural gas price liberalization has the adverse effects on economic growth and policy makers should be cautious in doing this policy. - Highlights: • Iran has been considered as a major natural gas producer in the world. • This paper examines the relationship between gas consumption and growth in Iran. • Positive impact of gas consumption on growth has been obtained. • The paper finds that gas consumption and income reinforce each other in Iran. • Natural gas price has also negative and significant impact on natural gas consumption in Iran

Benefits of real-time gas management

International Nuclear Information System (INIS)

Nolty, R.; Dolezalek, D. Jr.

1994-01-01

In today's competitive gas gathering, processing, storage and transportation business environment, the requirements to do business are continually changing. These changes arise from government regulations such as the amendments to the Clean Air Act concerning the environment and FERC Order 636 concerning business practices. Other changes are due to advances in technology such as electronic flow measurement (EFM) and real-time communications capabilities within the gas industry. Gas gathering, processing, storage and transportation companies must be flexible in adapting to these changes to remain competitive. These dynamic requirements can be met with an open, real-time gas management computer information system. Such a system provides flexible services with a variety of software applications. Allocations, nominations management and gas dispatching are examples of applications that are provided on a real-time basis. By providing real-time services, the gas management system enables operations personnel to make timely adjustments within the current accounting period. Benefits realized from implementing a real-time gas management system include reduced unaccountable gas, reduced imbalance penalties, reduced regulatory violations, improved facility operations and better service to customers. These benefits give a company the competitive edge. This article discusses the applications provided, the benefits from implementing a real-time gas management system, and the definition of such a system

Crude oil and natural gas supplies and demands for Denmark

International Nuclear Information System (INIS)

Mackay, R.M.; Probert, S.D.

1995-01-01

A novel technique for forecasting the supply and extraction life-cycle of a depleting fossil fuel resource has been developed. The supply side utilises a 'skewed-normal production-profile' model that yields a better representation than earlier approaches. A simple model for extrapolating crude oil and natural gas demands has also been devised, based on the so called 'modified logit function'. The predicted crude oil and natural gas balances for the period up to AD 2010 indicate the disparity between indigenous production and future consumption for Denmark. These forecasts depend on current estimates of remaining oil and gas reserves. It will consequently be necessary to revise periodically the present projections as more reliable reserve estimates become available. (author)

Canadian natural gas market dynamics and pricing : an update

International Nuclear Information System (INIS)

2002-10-01

This energy market assessment (EMA) report discusses natural gas price formation and describes the current functioning of regional gas markets in Canada. This EMA also describes the factors affecting the price of natural gas in Canada and examines natural gas markets on a region-by region basis. It is shown that as part of an integrated North American market, prices of natural gas in Canada reflect supply and demand factors in both Canada and the United States. During the low oil price period of 1997/1998, high demand for natural gas outpaced the supply because of low drilling and production activity by producers. In response to the increased demand and lower levels of supply, the price of natural gas increased significantly in 1999 and 2000. This was followed by a period of market adjustment. The importance of electronic trading systems for enhancing price discovery was also discussed with reference to how spot and futures markets allow market participants to manage price volatility. It was determined that Canadians have had access to natural gas on terms and conditions equal to export customers, and at equal pricing. In early November 2000, natural gas prices in North American began to rise due to low levels of natural gas in storage. The price shocks were felt unevenly across the North American market. In response to the high prices, consumers conserved energy use, and many industrial users switched to cheaper fuels. By the spring 2001, demand continued to decrease at a time when production was high. These factors contributed to the downward pressure on gas prices. This EMA discusses the structure of market transactions and market adjustment mechanisms. It is presented in the context of the approaching 2002/2003 winter season where the tightening between natural gas supply and demand is expected to result in price volatility. 28 figs

Combined utilization of biogas and natural gas

International Nuclear Information System (INIS)

Jensen, J.; Tafdrup, S.; Christensen, J.

1997-01-01

The Danish natural gas network has been established during the past 10 years. Running parallel with this a small but growing production of biogas from centralized biogas plants and landfills has been developed. The annual biogas production is expected to keep growing and increase tenfold in the next 25 year period with a reduction of green house gas emissions as one of the important incentives. The last years' development and expansion of the Danish biogas sector has shown a need for combined utilization of biogas and natural gas. If larger volumes of biogas are present, upgrading and distribution by the natural gas network may be an alternative to combined utilization. (au) 12 refs

LQ Optimal Sliding Mode Control of Periodic Review Perishable Inventories with Transportation Losses

OpenAIRE

Leśniewski, Piotr; Bartoszewicz, Andrzej

2013-01-01

In this work we apply the control-theoretic approach to design a new replenishment strategy for inventory systems with perishable stock. Such systems are supposed to effectively satisfy an unknown and permanently time-varying consumers’ demand. The main obstacle of achieving this goal is the need of obtaining supplies from a distant source. During the supply process goods are inevitably lost due to various causes. Furthermore, those goods which successfully arrive at the distribution center s...

Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences

Science.gov (United States)

Paull, C K; Caress, D W; Thomas, Hans; Lundsten, Eve M.; Anderson, Kayce; Gwiazda, Roberto; Riedel, M; McGann, Mary; Herguera, J C

2015-01-01

High-resolution multibeam bathymetry data collected with an autonomous underwater vehicle (AUV) complemented by compressed high-intensity radar pulse (Chirp) profiles and remotely operated vehicle (ROV) observations and sediment sampling reveal a distinctive rough topography associated with seafloor gas venting and/or near-subsurface gas hydrate accumulations. The surveys provide 1 m bathymetric grids of deep-water gas venting sites along the best-known gas venting areas along the Pacific margin of North America, which is an unprecedented level of resolution. Patches of conspicuously rough seafloor that are tens of meters to hundreds of meters across and occur on larger seafloor topographic highs characterize seepage areas. Some patches are composed of multiple depressions that range from 1 to 100 m in diameter and are commonly up to 10 m deeper than the adjacent seafloor. Elevated mounds with relief of >10 m and fractured surfaces suggest that seafloor expansion also occurs. Ground truth observations show that these areas contain broken pavements of methane-derived authigenic carbonates with intervening topographic lows. Patterns seen in Chirp profiles, ROV observations, and core data suggest that the rough topography is produced by a combination of diagenetic alteration, focused erosion, and inflation of the seafloor. This characteristic texture allows previously unknown gas venting areas to be identified within these surveys. A conceptual model for the evolution of these features suggests that these morphologies develop slowly over protracted periods of slow seepage and shows the impact of gas venting and gas hydrate development on the seafloor morphology.

The logic of natural gas penetration in Europe

International Nuclear Information System (INIS)

Bernardet, C.

1992-01-01

This paper is trying first to bring out some characteristic lines from the thirty years period of natural gas market growth in Europe: triggering role of domestic gas resources, relay by imports, background from an existing manufactured gas industry. The different roles of bulk usages and scattered ones are underlined. Through an example it is showed that market conditions are relying on a rapid shift of the gas prices competitiveness and on the historical opportunity of space heating growth. In a second part, this paper analyses in each great sector of consumption that could sustain the growth to come of natural gas in Europe. This development relies on marketing forces and on the disposal of new usages for gas and new services for customers, with the benefit from technological headway. 8 figs

Retailer's optimal credit period and cycle time in a supply chain for deteriorating items with up-stream and down-stream trade credits

Science.gov (United States)

Mahata, Gour Chandra

2015-09-01

In practice, the supplier often offers the retailers a trade credit period and the retailer in turn provides a trade credit period to her/his customer to stimulate sales and reduce inventory. From the retailer's perspective, granting trade credit not only increases sales and revenue but also increases opportunity cost (i.e., the capital opportunity loss during credit period) and default risk (i.e., the percentage that the customer will not be able to pay off his/her debt obligations). Hence, how to determine credit period is increasingly recognized as an important strategy to increase retailer's profitability. Also, the selling items such as fruits, fresh fishes, gasoline, photographic films, pharmaceuticals and volatile liquids deteriorate continuously due to evaporation, obsolescence and spoilage. In this paper, we propose an economic order quantity model for the retailer where (1) the supplier provides an up-stream trade credit and the retailer also offers a down-stream trade credit, (2) the retailer's down-stream trade credit to the buyer not only increases sales and revenue but also opportunity cost and default risk, and (3) the selling items are perishable. Under these conditions, we model the retailer's inventory system as a profit maximization problem to determine the retailer's optimal replenishment decisions under the supply chain management. We then show that the retailer's optimal credit period and cycle time not only exist but also are unique. We deduce some previously published results of other researchers as special cases. Finally, we use some numerical examples to illustrate the theoretical results.

The use of natural gas in the catering kitchen

International Nuclear Information System (INIS)

Holwerda, B.

1995-01-01

Extensive use is made of electricity in professional catering. Yet, the advantages of natural gas are obvious: energy costs are considerably lower as well as nitrogen oxide and carbon dioxide emissions. Generally, the amortization period of natural gas appliances is two years, sometimes even less than six months. In co-operation with the energy utilities and within the framework of the Marketing Plan for the Public Gas Supply (MOG), Gasunie informs the various target groups, including caterers, of the advantages of natural gas. At the moment five projects have already been carried out. 4 ills

Removal of gas phase low-concentration toluene over Mn, Ag and Ce modified HZSM-5 catalysts by periodical operation of adsorption and non-thermal plasma regeneration.

Science.gov (United States)

Wang, Wenzheng; Wang, Honglei; Zhu, Tianle; Fan, Xing

2015-07-15

Ag/HZSM-5, Mn/HZSM-5, Ce/HZSM-5, Ag-Mn/HZSM-5 and Ce-Mn/HZSM-5 were prepared by impregnation method. Both their adsorption capacity and catalytic activity were investigated for the removal of gas phase low-concentration toluene by periodical operation of adsorption and non-thermal plasma regeneration. Results show that catalysts loaded with Ag (Ag/HZSM-5 and Ag-Mn/HZSM-5) had larger adsorption capacity for toluene than the other catalysts. And Ag-Mn/HZSM-5 displayed the best catalytic performance for both toluene oxidation by non-thermal plasma and byproducts suppression. On the other hand, the deactivated catalyst can be fully regenerated by calcining in air stream when its adsorption capacity and catalytic activity of the Ag-Mn/HZSM-5 catalyst was found to be decreased after 10 cycles of periodical adsorption and non-thermal regeneration. Copyright © 2015. Published by Elsevier B.V.

Limits on replenishment of the resting CD4+ T cell reservoir for HIV in patients on HAART.

Directory of Open Access Journals (Sweden)

Ahmad R Sedaghat

2007-08-01

Full Text Available Whereas cells productively infected with human immunodeficiency virus type 1 (HIV-1 decay rapidly in the setting of highly active antiretroviral therapy (HAART, latently infected resting CD4(+ T cells decay very slowly, persisting for the lifetime of the patient and thus forming a stable reservoir for HIV-1. It has been suggested that the stability of the latent reservoir is due to low-level viral replication that continuously replenishes the reservoir despite HAART. Here, we offer the first quantitative study to our knowledge of inflow of newly infected cells into the latent reservoir due to viral replication in the setting of HAART. We make use of a previous observation that in some patients on HAART, the residual viremia is dominated by a predominant plasma clone (PPC of HIV-1 not found in the latent reservoir. The unique sequence of the PPC serves as a functional label for new entries into the reservoir. We employ a simple mathematical model for the dynamics of the latent reservoir to constrain the inflow rate to between 0 and as few as 70 cells per day. The magnitude of the maximum daily inflow rate is small compared to the size of the latent reservoir, and therefore any inflow that occurs in patients on HAART is unlikely to significantly influence the decay rate of the reservoir. These results suggest that the stability of the latent reservoir is unlikely to arise from ongoing replication during HAART. Thus, intensification of standard HAART regimens should have minimal effects on the decay of the latent reservoir.

Transient heat transfer for helium gas flowing over a horizontal cylinder with exponentially increasing heat input

International Nuclear Information System (INIS)

Liu, Qiusheng; Fukuda, Katsuya

2003-01-01

The transient heat transfer coefficients for forced convection flow of helium gas over a horizontal cylinder were measured under wide experimental conditions. The platinum cylinder with a diameter of 1.0 mm was used as test heater and heated by electric current with an exponentially increasing heat input of Q 0 exp(t/τ). The gas flow velocities ranged from 5 to 35 m/s, the gas temperatures ranged from 25 to 80degC, and the periods of heat generation rate, τ, ranged from 40 ms to 20 s. The surface superheat and heat flux increase exponentially as the heat generation rate increases with the exponential function. It was clarified that the heat transfer coefficient approaches the quasi-steady-state one for the period τ longer than about 1 s, and it becomes higher for the period shorter than around 1 s. The transient heat transfer shows less dependence on the gas flowing velocity when the period becomes very shorter. The gas temperature in this study shows little influence on the heat transfer coefficient. Semi-empirical correlation for quasi-steady-state heat transfer was obtained based on the experimental data. The ratios of transient Nusselt number Nu tr to quasi-steady-state Nusselt number Nu st at various periods, flow velocities, and gas temperatures were obtained. The heat transfer shifts to the quasi-steady-state heat transfer for longer periods and shifts to the transient heat transfer for shorter periods at the same flow velocity. It also approaches the quasi-steady-state one for higher flow velocity at the same period. Empirical correlation for transient heat transfer was also obtained based on the experimental data. (author)

A multi vector energy analysis for interconnected power and gas systems

International Nuclear Information System (INIS)

Devlin, Joseph; Li, Kang; Higgins, Paraic; Foley, Aoife

2017-01-01

Highlights: • The first multi vector energy system analysis for Britain and Ireland is performed. • Extreme weather driven gas demands were utilised to increase gas system stress. • GB gas system is capable of satisfying demand but restricts gas generator ramping. • Irish gas system congestion causes a 40% increase in gas generator short run cost. • Gas storage in Ireland relieved congestion reduced operational costs by 14%. - Abstract: This paper presents the first multi vector energy analysis for the interconnected energy systems of Great Britain (GB) and Ireland. Both systems share a common high penetration of wind power, but significantly different security of supply outlooks. Ireland is heavily dependent on gas imports from GB, giving significance to the interconnected aspect of the methodology in addition to the gas and power interactions analysed. A fully realistic unit commitment and economic dispatch model coupled to an energy flow model of the gas supply network is developed. Extreme weather events driving increased domestic gas demand and low wind power output were utilised to increase gas supply network stress. Decreased wind profiles had a larger impact on system security than high domestic gas demand. However, the GB energy system was resilient during high demand periods but gas network stress limited the ramping capability of localised generating units. Additionally, gas system entry node congestion in the Irish system was shown to deliver a 40% increase in short run costs for generators. Gas storage was shown to reduce the impact of high demand driven congestion delivering a reduction in total generation costs of 14% in the period studied and reducing electricity imports from GB, significantly contributing to security of supply.

Market fundamentals, competition and natural-gas prices

International Nuclear Information System (INIS)

Hulshof, Daan; Maat, Jan-Pieter van der; Mulder, Machiel

2016-01-01

After the liberalisation of the gas industry, trading hubs have emerged in Europe. Although these hubs appear to be liquid market places fostering gas-to-gas competition, the efficiency of the gas market remains a topic of interest as a fair share of gas is still traded through long-term contracts with prices linked to the oil price while the number of gas suppliers to the European market is limited. In order to assess the efficiency of the gas market, we analyse the day-ahead spot price at the Dutch gas hub over the period 2011–2014. We find that the oil price had a small positive impact on the gas price. Changes in the concentration on the supply side did not affect the movement in gas prices. The availability of gas in storages and the outside temperature negatively influenced the gas price. We also find that the gas price was related to the production of wind electricity. Overall, we conclude that the day-ahead gas prices are predominantly determined by gas-market fundamentals. Policies to further integrate gas markets within Europe may extend this gas-to-gas competition to a larger region. - Highlights: •We analyse the development of the day-ahead spot price at TTF over 2011–2014. •The oil price had a small impact on the gas price, while the coal price had no effect. •Changes in the concentration on the supply side did not affect the gas prices. •The gas prices are predominantly determined by weather and storage availability. •Policies to integrate gas markets foster gas-to-gas competition.

Growth arrest specific protein (GAS) 6

DEFF Research Database (Denmark)

Haase, T N; Rasmussen, Morten; Jaksch, C A M

2013-01-01

using RNA microarray and quantitative PCR. The role of a differentially expressed gene, growth arrest specific protein 6 (GAS6), was evaluated in vitro using neonatal rat islets. Results The mRNA level of Gas6, known to be mitogenic in other tissues, was reduced in LP offspring. The mRNA content of Mafa...... was increased in LP offspring suggesting an early maturation of beta cells. When applied in vitro, GAS6 increased proliferation of neonatal pancreatic beta cells, while reducing glucose-stimulated insulin secretion without changing the total insulin content of the islets. In addition, GAS6 decreased the m......RNA content of Mafa. Conclusions/interpretation We propose a role for GAS6 in the regulation of pancreatic beta cells in the critical period around the time of birth. Our results support the hypothesis that the reduced beta cell mass seen in LP offspring is caused by a change in the intra-uterine environment...

US production of natural gas from tight reservoirs

International Nuclear Information System (INIS)

1993-01-01

For the purposes of this report, tight gas reservoirs are defined as those that meet the Federal Energy Regulatory Commission's (FERC) definition of tight. They are generally characterized by an average reservoir rock permeability to gas of 0.1 millidarcy or less and, absent artificial stimulation of production, by production rates that do not exceed 5 barrels of oil per day and certain specified daily volumes of gas which increase with the depth of the reservoir. All of the statistics presented in this report pertain to wells that have been classified, from 1978 through 1991, as tight according to the FERC; i.e., they are ''legally tight'' reservoirs. Additional production from ''geologically tight'' reservoirs that have not been classified tight according to the FERC rules has been excluded. This category includes all producing wells drilled into legally designated tight gas reservoirs prior to 1978 and all producing wells drilled into physically tight gas reservoirs that have not been designated legally tight. Therefore, all gas production referenced herein is eligible for the Section 29 tax credit. Although the qualification period for the credit expired at the end of 1992, wells that were spudded (began to be drilled) between 1978 and May 1988, and from November 5, 1990, through year end 1992, are eligible for the tax credit for a subsequent period of 10 years. This report updates the EIA's tight gas production information through 1991 and considers further the history and effect on tight gas production of the Federal Government's regulatory and tax policy actions. It also provides some high points of the geologic background needed to understand the nature and location of low-permeability reservoirs

Accumulative effect of food residues on intestinal gas production.

Science.gov (United States)

Mego, M; Accarino, A; Malagelada, J-R; Guarner, F; Azpiroz, F

2015-11-01

As mean transit time in the colon is longer than the interval between meals, several consecutive meal loads accumulate, and contribute to colonic biomass. Our aim was to determine the summation effect of fermentable food residues on intestinal gas production. In eight healthy subjects, the volume of endogenous intestinal gas produced in the intestine over a 4-h period was measured by means of a wash-out technique, using an exogenous gas infusion into the jejunum (24 mL/min) and collection of the effluent via a rectal Foley catheter. The exogenous gas infused was labeled (5% SF6 ) to calculate the proportion of endogenous intestinal gas evacuated. In each subject, four experiments were performed ≥1 week apart combining a 1-day high- or low-flatulogenic diet with a test meal or fast. Basal conditions: on the low-flatulogenic diet, intestinal gas production during fasting over the 4-h study period was 609 ± 63 mL. Effect of diet: during fasting, intestinal gas production on the high-flatulogenic diet was 370 ± 146 mL greater than on the low-flatulogenic diet (p = 0.040). Effect of test meal: on the low-flatulogenic diet, intestinal gas production after the test meal was 681 ± 114 mL greater than during fasting (p = 0.001); a similar effect was observed on the high-flatulogenic diet (599 ± 174 mL more intestinal gas production after the test meal than during fasting; p = 0.021). Our data demonstrate temporal summation effects of food residues on intestinal gas production. Hence, intestinal gas production depends on pre-existing and on recent colonic loads of fermentable foodstuffs. © 2015 John Wiley & Sons Ltd.

Early action to reduce greenhouse gas emissions before the commitment period of the Kyoto protocol: advantages and disadvantages.

Science.gov (United States)

Michaelowa, A; Rolfe, C

2001-09-01

Current "business as usual" projections suggest greenhouse gas emissions from industrialized nations will grow substantially over the next decade. However, if it comes into force, the Kyoto Protocol will require industrialized nations to reduce emissions to an average of 5% below 1990 levels in the 2008-2012 period. Taking early action to close this gap has a number of advantages. It reduces the risks of passing thresholds that trigger climate change "surprises." Early action also increases future generations' ability to choose greater levels of climate protection, and it leads to faster reductions of other pollutants. From an economic sense, early action is important because it allows shifts to less carbon-intensive technologies during the course of normal capital stock turnover. Moreover, many options for emission reduction have negative costs, and thus are economically worthwhile, because of paybacks in energy costs, healthcare costs, and other benefits. Finally, early emission reductions enhance the probability of successful ratification and lower the risk of noncompliance with the protocol. We discuss policy approaches for the period prior to 2008. Disadvantages of the current proposals for Credit for Early Action are the possibility of adverse selection due to problematic baseline calculation methods as well as the distributionary impacts of allocating a part of the emissions budget already before 2008. One simple policy without drawbacks is the so-called baseline protection, which removes the disincentive to early action due to the expectation that businesses may, in the future, receive emission rights in proportion to past emissions. It is particularly important to adopt policies that shift investment in long-lived capital stock towards less carbon-intensive technologies and to encourage innovation and technology development that will reduce future compliance costs.

Guidelines for clockspeed acceleration in the US natural gas transmission industry

International Nuclear Information System (INIS)

Weijermars, Ruud

2010-01-01

This study presents the clockspeed analysis of a peer group comprising six major integrated US energy companies with substantial US interstate natural gas pipeline business activities: El Paso, Williams, NiSource, Kinder Morgan, MidAmerican and CMS Energy. For this peer group, the three clockspeed accelerators have been benchmarked at both corporate level and gas transmission business level, using time-series analysis and cross-sectional analysis over a 6-year period (2002-2007). The results are visualized in so-called clockspeed radargraphs. Overall corporate clockspeed winners - over the performance period studied - are: Williams, El Paso and Kinder Morgan; MidAmerican is a close follower. Corporate clockspeed laggards are: CMS Energy and NiSource. The peer group ranking for the natural gas transmission business segment shows similar clockspeed winners, but with different ranking in the following order: Kinder Morgan, MidAmerican and El Paso; Williams is a close follower. Clockspeed laggards for the natural gas transmission segments coincide with the corporate clockspeed laggards of the peer group: CMS Energy and NiSource (over the performance period studied); laggards of the past may become clockspeed leaders of the future if adjustments are made. Practical recommendations are formulated for achieving competitive clockspeed optimization in the US gas transmission industry as a whole. Recommendations for clockspeed acceleration at individual companies are also given. Although the US natural gas market is subject to specific regulations and its own geographical dynamics, this study also provides hints for improving the competitive clockspeed performance of gas transmission companies elsewhere, in other world regions. (author)

Guidelines for clockspeed acceleration in the US natural gas transmission industry

Energy Technology Data Exchange (ETDEWEB)

Weijermars, Ruud [Department of Geotechnology, Delft University of Technology, PO Box 5048, 2600GA Delft (Netherlands)

2010-08-15

This study presents the clockspeed analysis of a peer group comprising six major integrated US energy companies with substantial US interstate natural gas pipeline business activities: El Paso, Williams, NiSource, Kinder Morgan, MidAmerican and CMS Energy. For this peer group, the three clockspeed accelerators have been benchmarked at both corporate level and gas transmission business level, using time-series analysis and cross-sectional analysis over a 6-year period (2002-2007). The results are visualized in so-called clockspeed radargraphs. Overall corporate clockspeed winners - over the performance period studied - are: Williams, El Paso and Kinder Morgan; MidAmerican is a close follower. Corporate clockspeed laggards are: CMS Energy and NiSource. The peer group ranking for the natural gas transmission business segment shows similar clockspeed winners, but with different ranking in the following order: Kinder Morgan, MidAmerican and El Paso; Williams is a close follower. Clockspeed laggards for the natural gas transmission segments coincide with the corporate clockspeed laggards of the peer group: CMS Energy and NiSource (over the performance period studied); laggards of the past may become clockspeed leaders of the future if adjustments are made. Practical recommendations are formulated for achieving competitive clockspeed optimization in the US gas transmission industry as a whole. Recommendations for clockspeed acceleration at individual companies are also given. Although the US natural gas market is subject to specific regulations and its own geographical dynamics, this study also provides hints for improving the competitive clockspeed performance of gas transmission companies elsewhere, in other world regions. (author)

Flammable gas tank safety program: Technical basis for gas analysis and monitoring

International Nuclear Information System (INIS)

Estey, S.D.

1998-01-01

Several Hanford waste tanks have been observed to exhibit periodic releases of significant quantities of flammable gases. Because potential safety issues have been identified with this type of waste behavior, applicable tanks were equipped with instrumentation offering the capability to continuously monitor gases released from them. This document was written to cover three primary areas: (1) describe the current technical basis for requiring flammable gas monitoring, (2) update the technical basis to include knowledge gained from monitoring the tanks over the last three years, (3) provide the criteria for removal of Standard Hydrogen Monitoring System(s) (SHMS) from a waste tank or termination of other flammable gas monitoring activities in the Hanford Tank farms

Trans-Caspian gas pipeline feasibility study. Volume 1

International Nuclear Information System (INIS)

1999-01-01

This study, conducted by Enron Engineering and Construction Company, was funded by the US Trade and Development Agency. The study provides detailed information concerning natural gas demand in Turkey and Southern Europe. The purpose of the study is to estimate the rate at which new gas can be absorbed in the Turkish market and be re-exported to the markets in Europe, as well as to forecast Turkish natural gas demand for the period up to 2020. The study also evaluates gas demand and pricing for the market in the 2002--2005 time frame. This is Volume 1 of a 3-volume report, and is divided into the following sections: (1) Task A: Gas Sales; (2) Task B: Initial Economic Screening; (3) Task D: Project Cost Analysis

Retention of radiolytic CO gas in irradiated pepper grains and irradiation detection of spices and dry grains with the level of stocked CO gas

International Nuclear Information System (INIS)

Furuta, M.; Dohmaru, T.; Katayama, T.; Toratani, H.; Takeda, A.

1995-01-01

The release of radiolytic CO gas from 60Co gamma-irradiated pepper seeds was unexpectedly slower than that of radiolytic H2 gas during a storage period after irradiation. These gases were retained in the grains and could be recovered by pulverization under gaslight condition. Using this procedure, 10-kGy-irradiated pepper grains could be distinguished from nonirradiated samples for more than 2 months by the level of CO and H2 gases. The patterns of CO change at 10, 20, and 30 kGy were similar, and the CO amounts were proportional to irradiation doses at any point of the storage period after irradiation. 60Co gamma-irradiated grains of allspice, cinnamon, cumin, polished rice, and wheat could be distinguished from nonirradiated ones by the level of retained CO gas even after 2 months of storage at room temperature. Thus, radiolytic CO gas could be an effective probe for rapid screening of irradiated pepper and dry grains

Friends of hot Jupiters. I. A radial velocity search for massive, long-period companions to close-in gas giant planets

Energy Technology Data Exchange (ETDEWEB)

Knutson, Heather A.; Ngo, Henry; Johnson, John Asher [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Fulton, Benjamin J.; Howard, Andrew W. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI (United States); Montet, Benjamin T.; Kao, Melodie; Hinkley, Sasha; Morton, Timothy D.; Muirhead, Philip S. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, Notre Dame, IN (United States); Bakos, Gaspar Á. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ (United States); Batygin, Konstantin, E-mail: hknutson@caltech.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

2014-04-20

In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 planets obtained using the Keck HIRES instrument, and find statistically significant accelerations in fifteen systems. Six of these systems have no previously reported accelerations in the published literature: HAT-P-10, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, and XO-2. We combine our radial velocity fits with Keck NIRC2 adaptive optics (AO) imaging data to place constraints on the allowed masses and orbital periods of the companions responsible for the detected accelerations. The estimated masses of the companions range between 1-500 M {sub Jup}, with orbital semi-major axes typically between 1-75 AU. A significant majority of the companions detected by our survey are constrained to have minimum masses comparable to or larger than those of the transiting planets in these systems, making them candidates for influencing the orbital evolution of the inner gas giant. We estimate a total occurrence rate of 51% ± 10% for companions with masses between 1-13 M {sub Jup} and orbital semi-major axes between 1-20 AU in our sample. We find no statistically significant difference between the frequency of companions to transiting planets with misaligned or eccentric orbits and those with well-aligned, circular orbits. We combine our expanded sample of radial velocity measurements with constraints from transit and secondary eclipse observations to provide improved measurements of the physical and orbital characteristics of all of the planets included in our survey.

A coupling model for gas diffusion and seepage in SRV section of shale gas reservoirs

Directory of Open Access Journals (Sweden)

Shusheng Gao

2017-03-01

Full Text Available A prerequisite to effective shale gas development is a complicated fracture network generated by extensive and massive fracturing, which is called SRV (stimulated reservoir volume section. Accurate description of gas flow behaviors in such section is fundamental for productivity evaluation and production performance prediction of shale gas wells. The SRV section is composed of bedrocks with varying sizes and fracture networks, which exhibit different flow behaviors – gas diffusion in bedrocks and gas seepage in fractures. According to the porosity and permeability and the adsorption, diffusion and seepage features of bedrocks and fractures in a shale gas reservoir, the material balance equations were built for bedrocks and fractures respectively and the continuity equations of gas diffusion and seepage in the SRV section were derived. For easy calculation, the post-frac bedrock cube was simplified to be a sphere in line with the principle of volume consistency. Under the assumption of quasi-steady flow behavior at the cross section of the sphere, the gas channeling equation was derived based on the Fick's laws of diffusion and the density function of gas in bedrocks and fractures. The continuity equation was coupled with the channeling equation to effectively characterize the complicated gas flow behavior in the SRV section. The study results show that the gas diffusivity in bedrocks and the volume of bedrocks formed by volume fracturing (or the scale of fracturing jointly determines the productivity and stable production period of a shale gas well. As per the actual calculation for the well field A in the Changning–Weiyuan Block in the Sichuan Basin, the matrix has low gas diffusivity – about 10−5 cm2/s and a large volume with an equivalent sphere radius of 6.2 m, hindering the gas channeling from bedrocks to fractures and thereby reducing the productivity of the shale gas well. It is concluded that larger scale of volume fracturing

Transient heat transfer for forced convection flow of helium gas

International Nuclear Information System (INIS)

Liu, Qiusheng; Fukuda, Katsuya; Sasaki, Kenji; Yamamoto, Manabu

1999-01-01

Transient heat transfer coefficients for forced convection flow of helium gas over a horizontal cylinder were measured using a forced convection test loop. The platinum heater with a diameter of 1.0 mm was heated by electric current with an exponential increase of Q 0 exp(t/τ). It was clarified that the heat transfer coefficient approaches the steady-state one for the period τ over 1 s, and it becomes higher for the period of τ shorter than 1 s. The transient heat transfer shows less dependent on the gas flowing velocity when the period becomes very shorter. Semi-empirical correlations for steady-state and transient heat transfer were developed based on the experimental data. (author)

On the conditions of magma mixing and its bearing on andesite production in the crust.

Science.gov (United States)

Laumonier, Mickael; Scaillet, Bruno; Pichavant, Michel; Champallier, Rémi; Andujar, Joan; Arbaret, Laurent

2014-12-15

Mixing between magmas is thought to affect a variety of processes, from the growth of continental crust to the triggering of volcanic eruptions, but its thermophysical viability remains unclear. Here, by using high-pressure mixing experiments and thermal calculations, we show that hybridization during single-intrusive events requires injection of high proportions of the replenishing magma during short periods, producing magmas with 55-58 wt% SiO2 when the mafic end-member is basaltic. High strain rates and gas-rich conditions may produce more felsic hybrids. The incremental growth of crustal reservoirs limits the production of hybrids to the waning stage of pluton assembly and to small portions of it. Large-scale mixing appears to be more efficient at lower crustal conditions, but requires higher proportions of mafic melt, producing more mafic hybrids than in shallow reservoirs. Altogether, our results show that hybrid arc magmas correspond to periods of enhanced magma production at depth.

PETROCHINA TO MAINTAIN TWO-DIGITAL GROWTH OF ITS GAS PRODUCTION

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

@@ Based on the information made available from the recent conference on natural gas development held in Chengdu, the capital of the natural gasenriched Sichuan Province, PetroChina will maintain a 14 percent growth for its natural gas production during the 1 lth Five-Year Plan period (2006-2010), owing to acceleration of the market development and pipeline construction in the downstream sector and rapid progress in the natural gas exploration.

Relating landfill gas emissions to atmospheric pressure using numerical modeling and state-space analysis

DEFF Research Database (Denmark)

Poulsen, T.G.; Christophersen, Mette; Moldrup, P.

2003-01-01

were applied: (I) State-space analysis was used to identify relations between gas flux and short-term (hourly) variations in atmospheric pressure. (II) A numerical gas transport model was fitted to the data and used to quantify short-term impacts of variations in atmospheric pressure, volumetric soil......-water content, soil gas permeability, soil gas diffusion coefficients, and biological CH4 degradation rate upon landfill gas concentration and fluxes in the soil. Fluxes and concentrations were found to be most sensitive to variations in volumetric soil water content, atmospheric pressure variations and gas...... permeability whereas variations in CH4 oxidation rate and molecular coefficients had less influence. Fluxes appeared to be most sensitive to atmospheric pressure at intermediate distances from the landfill edge. Also overall CH4 fluxes out of the soil over longer periods (years) were largest during periods...

Gas sector developments in Trinidad and Tobago

International Nuclear Information System (INIS)

McGuire, G.

1997-01-01

The outlook for the natural gas industry in Trinidad and Tobago was discussed. The country's proven reserves, as of January 1997, were estimated at 16.1 trillion cubic feet. The National Gas Company (NGC) is key to expansion of the country's gas business. In 1996 NGC sold 683 million cubic feet of natural gas. The petrochemical sector accounted for 57.6 per cent of sales, power generation 22.4 per cent and metal and other heavy industry 19 per cent. Amoco, Enron and British Gas are the principal suppliers. Natural gas demand in Trinidad and Tobago is predicted to surpass the 1.5 billion cubic feet per day threshold by the year 2001, rising to 2.1 billion cubic feet per day by 2006. During the 1997-2001 period, gas sales to the petrochemical sector will increase by a compounded average of 24 per cent per year due to new plant expansions in the methanol and ammonia sectors. Trinidad expects to be firmly established as the world's leading exporter of methanol and ammonia by the year 2001. Increased gas sales will also be stimulated by the proposed establishment of an aluminium smelter in Trinidad. 1 tab., 1 fig

Economical Utilization of Associated Gas in Nigeria

Directory of Open Access Journals (Sweden)

Lukman Obayopo Alimi

2014-07-01

Full Text Available Oil production is often accompanied by associated natural gas as valuable by-product of oil processing. Large amount of this vital energy component is flared during these processes, mostly in developing countries. For a longer period of time more gas is flares in Nigeria than anywhere else in Africa and second to Russian in the world, with daily estimates of roughly 2.5 billion cubic feet. This is equivalent to around 40% of all Africa´s natural gas consumption, and annual financial loss to Nigeria is about 1.8 billion Euros. Gas flaring contributes to major environmental pollution problems, which affects oil producing areas of the Niger Delta in Nigeria. This research attempts to look into the environmental issues in the region and proposes possible solutions, with recommendations that will contribute to improve associated gas utilization. This study describes gas to liquid (GTL conversion technology as a sustainable option to utilize associated gas in Nigeria, and also evaluates the economic attractiveness of the process. This conversion technology could contribute to total elimination of gas flaring and reduces the overdependence on importation of refined products (petrol, diesel and kerosene from foreign countries into Nigeria.

MASSIVE SATELLITES OF CLOSE-IN GAS GIANT EXOPLANETS

International Nuclear Information System (INIS)

Cassidy, Timothy A.; Johnson, Robert E.; Mendez, Rolando; Arras, Phil; Skrutskie, Michael F.

2009-01-01

We study the orbits, tidal heating and mass loss from satellites around close-in gas giant exoplanets. The focus is on large satellites which are potentially observable by their transit signature. We argue that even Earth-size satellites around hot Jupiters can be immune to destruction by orbital decay; detection of such a massive satellite would strongly constrain theories of tidal dissipation in gas giants, in a manner complementary to orbital circularization. The star's gravity induces significant periodic eccentricity in the satellite's orbit. The resulting tidal heating rates, per unit mass, are far in excess of Io's and dominate radioactive heating out to planet orbital periods of months for reasonable satellite tidal Q. Inside planet orbital periods of about a week, tidal heating can completely melt the satellite. Lastly, we compute an upper limit to the satellite mass loss rate due to thermal evaporation from the surface, valid if the satellite's atmosphere is thin and vapor pressure is negligible. Using this upper limit, we find that although rocky satellites around hot Jupiters with orbital periods less than a few days can be significantly evaporated in their lifetimes, detectable satellites suffer negligible mass loss at longer orbital periods.

Effect of gas recirculation in a pilot-scale cow-dung digester

Energy Technology Data Exchange (ETDEWEB)

Pathak, B N; Kulkarni, D N; Dave, J M; Mohanrao, G J

1965-01-01

Laboratory experiments showed that if, during anaerobic digestion of cow manure, the contents of the digestion vessel are mixed by recirculating gas, nearly twice as much gas is produced, and there is less variation in the temperature of the digesting liquor, the pH value, the carbon-dioxide content of the gas, and the reduction in volatile matter. Results of experiments during which gas was recirculated for periods ranging from 0 to 4 hours are tabulated.

The impact of the shale gas revolution on the U.S. and Japanese natural gas markets

International Nuclear Information System (INIS)

Wakamatsu, Hiroki; Aruga, Kentaka

2013-01-01

We investigated whether the increase in the US shale gas production changed the structures of the US and Japanese natural gas markets using market data for the period 2002:5–2012:5. Our analysis consists of a structural break test and market integration analysis. The Bai and Perron structural break test detected a break point of natural gas prices and consumption in 2005 as well as other external shocks – Hurricane Katrina and the Lehman Shock – that are irrelevant to shale gas development. We eliminated the impact of these shocks by separating the data set using the breaks identified in our analysis. We found the breaks skewed the estimation; a market linkage existed between the US and Japanese markets in the original data set, while it did not in the separated data. The vector autoregressive (VAR) model also indicated a significant change before and after the break point; the US market had a one-side influence on the Japanese market before 2005, but the influence disappeared after 2005. Our results implied that the shale gas revolution, triggered by the increase in shale gas production in 2005, caused the change in the relationship between the US and Japanese natural gas markets. -- Highlights: •We investigated the effect of the US shale gas revolution on gas markets. •A break test detected the shale gas revolution occurred in 2005. •The VAR model found a significant change before and after the break point. •The US influence on the Japanese market disappeared after 2005

Calculation of gas release from DC and AC arc furnaces in a foundry

Science.gov (United States)

Krutyanskii, M. M.; Nekhamin, S. M.; Rebikov, E. M.

2016-12-01

A procedure for the calculation of gas release from arc furnaces is presented. The procedure is based on the stoichiometric ratios of the oxidation of carbon in liquid iron during the oxidation heat period and the oxidation of iron from a steel charge by oxygen in the period of solid charge melting during the gas exchange of the furnace cavity with the external atmosphere.

Impact of electric industry deregulation on gas markets: a power marketer's perspective

International Nuclear Information System (INIS)

Jahns, F.H.

1996-01-01

The impact of electric industry deregulation on gas markets was examined. The presentation included industry comparisons of 1994 gas total revenues versus electricity total revenues for residential, commercial, and industrial use. A chart forecasting the outlook for gas-fired generation of electric power indicated that the use of natural gas as feedstock for power generation will increase from 12% to 37% during the period 1994 to 2003. 16 figs

Porous Silicon Structures as Optical Gas Sensors.

Science.gov (United States)

Levitsky, Igor A

2015-08-14

We present a short review of recent progress in the field of optical gas sensors based on porous silicon (PSi) and PSi composites, which are separate from PSi optochemical and biological sensors for a liquid medium. Different periodical and nonperiodical PSi photonic structures (bares, modified by functional groups or infiltrated with sensory polymers) are described for gas sensing with an emphasis on the device specificity, sensitivity and stability to the environment. Special attention is paid to multiparametric sensing and sensor array platforms as effective trends for the improvement of analyte classification and quantification. Mechanisms of gas physical and chemical sorption inside PSi mesopores and pores of PSi functional composites are discussed.

Radon in soil gas in Kosovo.

Science.gov (United States)

Kikaj, Dafina; Jeran, Zvonka; Bahtijari, Meleq; Stegnar, Peter

2016-11-01

An assessment of the radiological situation due to exposure to radon and gamma emitting radionuclides was conducted in southern Kosovo. This study deals with sources of radon in soil gas. A long-term study of radon concentrations in the soil gas was carried out using the SSNTDs (CR-39) at 21 different locations in the Sharr-Korabi zone. The detectors were exposed for an extended period of time, including at least three seasonal periods in a year and the sampling locations were chosen with respect to lithology. In order to determine the concentration of the natural radioactive elements 238 U and 226 Ra, as a precursor of 222 Rn, soil samples were collected from each measuring point from a depth of 0.8 m, and measured by gamma spectrometry. The levels (Bq kg -1 ) of naturally occurring radionuclides and levels (kBq m -3 ) of radon in soil gas obtained at a depth 0.8 m of soil were: 21-53 for 226 Ra, 22-160 for 238 U and 0.295-32 for 222 Rn. With respect to lithology, the highest value for 238 U and 226 Ra were found in limestone and the highest value for 222 Rn was found in metamorphic rocks. In addition, the results showed seasonal variations of the measured soil gas radon concentrations with maximum concentration in the spring months. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ranking Canadian oil and gas projects using TOPSIS

Directory of Open Access Journals (Sweden)

Seyed Jafar Sadjadi

2017-08-01

Full Text Available One of the primary concerns for investment in oil and gas projects is to have a comprehensive understanding on different issues associated with this industry. The industry is mainly influ-enced by the price of oil and gas and in some events, many production units have been forced to shut down solely because of low price of oil and gas. Environmental issues are other important factors, which may put pressure on Canada’s political affairs since the country has strong com-mitment to reduce green gas effect. In this paper, we introduce a multi-criteria decision making method, which helps us rank different projects in terms of investment. The proposed study con-siders different investment factors including net present value, rate of return, benefit-cost analy-sis and payback period along with the intensity of green gas effects for ranking the present oil and gas projects in Canada.

Gas MGP: review and outlook

International Nuclear Information System (INIS)

Lafon, M.

2007-01-01

The multi-year guidance plan (MGP), publicly disclosed on March 7, 2007, by the French Ministry of Economy and Finances, is the first report by the parliament on the development of the gas sector, in line with the January 3, 2003 law. It was issued for fiscal year 2006 and covers the period spanning 2006-2015. Drafted by a steering committee, chaired by J.P. Falque-Pierrotin and composed of representatives from the relevant ministries, the document involved hearing many experts from the gas sector (industry, commerce, professional unions, government agencies). An exercise in guidance planning, this document is of a forward-looking nature and aims at setting out a shared understanding of demand and outlook for supply. It is also designed to offer analysis of natural gas supply and demand in order to estimate infrastructure capacity

Method of separating radioactive krypton gas

International Nuclear Information System (INIS)

Kimura, Shigeru; Awada, Yoshihisa.

1975-01-01

Object: To effectively and safely separate and recover Kr-85, which requires a long storage period for attenuating radioactivity, from a mixture gas consisting of Kr-85 and Xe by a liquefaction distillation method. Structure: A mixture gas consisting of Kr and Xe is subjected to heat exchange in a cooler with Freon gas from a plurality of distillation towers for its temperature reduction from normal temperature to a lower temperature, and then it is supplied to a distillation tower. The distillation tower is held at a pressure above 15 ata, preferably around 20 ata, and a condenser provided at the top of the distillation tower is furnished with Freon as cooling medium. The rare mixture gas is distilled by liquefaction within a distillation tower, and Kr-85 is obtained from a top duct while obtaining Xe from a bottom duct. Xe after separation by liquefaction is returned to a rare mixture gas supply inlet of a liquefaction distillation means for repeated refinement in the distillation tower. (Kamimura, M.)

The law of one price in global natural gas markets. A threshold cointegration analysis

Energy Technology Data Exchange (ETDEWEB)

Nick, Sebastian; Tischler, Benjamin

2014-11-15

The US and UK markets for natural gas are connected by arbitrage activity in the form of shifting trade volumes of liquefied natural gas (LNG). We empirically investigate the degree of integration between the US and the UK gas markets by using a threshold cointegration approach that is in accordance with the law of one price and explicitly accounts for transaction costs. Our empirical results reveal a high degree of market integration for the period 2000-2008. Although US and UK gas prices seemed to have decoupled between 2009 and 2012, we still find a certain degree of integration pointing towards significant regional price arbitrage. However, high threshold estimates in the latter period indicate impediments to arbitrage that are by far surpassing the LNG transport costs difference between the US and UK gas market.

Influence of storage period on properties of biopolymer packaging materials and pouches

Directory of Open Access Journals (Sweden)

Bulut Sandra N.

2017-01-01

Full Text Available Bilayer biodegradable films based on pumpkin oil cake (PuOC and zein, as well as pouches made from these materials, were prepared, and the changes of their mechanical, physicochemical and barrier properties were analyzed during four weeks of storage. Heat seal quality of formed pouches and composition of the gas atmosphere in the pouches were also monitored. The results showed that the bilayer film had a thickness of 300 ± 10 (μm, and no its changes were observed during the storage time. The tensile strength of the tested film increased slightly in the third week, but the elongation at break showed a decreasing trend during the whole storage period. The decreases in the moisture content, total soluble matter and swelling of the obtained film, were also observed. After one month of storage, the O2 transmission rate of tested films, increased from 27 to 64 (ml/m2 24h 1 bar, and the CO2 gas transmission rate from 147 to 188 (ml/m2 24h 1 bar. The heat seal strength of the PuOC/Zein pouches decreased during the whole storage period. The percentage of O2 in PuOC/Zein pouches increased up to 7 times during the storage period; however, the percentage of CO2 decreased up to 18 times already after one week, and then remained stable in the rest of the storage period. These results are, to a smaller extent, due to the gas transmission rate through the material, especially for CO2 , and to a greater extent, due to the low heat seal strength, which decreased through the storage period, and probably influenced the content of the gases in the pouches.[Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46010

Design of a Natural Gas Liquefaction System with Minimum Components

International Nuclear Information System (INIS)

Bergese, Franco

2004-01-01

In this work an economic method for liquefying natural gas by diminishing its temperature by means of the Joule-Thomson effect is presented.The pressures from and to which the gas must be expanded arose from a thermodynamic calculation optimizing the cost per unit mass of Liquefied Natural Gas LNG).It was determined that the gas should be expanded from 200 atm to 4 atm.This expansion ratio can be used in different scales.Large Scale: liquefaction of gas at well.It takes advantage of the fact that the gas inside the well is stored at high pressure.The gas is expanded in a valve / nozzle and then compressed to the pressure of the local pipeline system.The objective of this project is to export natural gas as LNG, which is transported by ships to the markets of consumption.Using this method of liquefaction, the LNG production levels are limited to a fraction of the production of the well, due to the injection of the un condensed gas into the local pipelines system.Medium Scale: A high pressure pipeline is the source of the gas.The expansion is performed and then the gas is again compressed to the pressure of a lower pressure pipeline into which the gas is injected.The pressure reductions of natural gas are performed nearby big cities.The aim of this project scale is the storage of fuel for gas thermal power plants during periods of low energy consumption for later burning when the resource is limited. Another possibility that offers this size of plant is the transportation of gas to regions where the resource is unavailable.This transportation would be carried out by means of cistern trucks, in the same way that conventional liquid fuels are transported.Small scale: the place of production would be a CNG refueling station. The source of gas is in this case a gas pipeline of urban distribution and the gas should be compressed with the compressor of the refueling station.Compressors have generally low loading factor and the periods of time when they are not producing

Mergers and acquisitions in the oil and gas industries

International Nuclear Information System (INIS)

Corlay, C.; Huby, D.

1999-01-01

This paper focuses on mergers and acquisitions in the oil and gas industries, and lists the most important mergers in terms of transaction value for the period 1981-1997, and plots oil and gas mergers and acquisitions activity by sector and by major region. The mean operation indicator in 1998 in terms of reserves, production and refining capacity of the major companies are tabulated. The impact of the mergers on the oil and gas markets are examined, and issues concerning these mergers and acquisitions are explored. (UK)

Mergers and acquisitions in the oil and gas industries

Energy Technology Data Exchange (ETDEWEB)

Corlay, C.; Huby, D. [Institut Francais du Petrole, Rueil-Malmaison (France)

1999-07-01

This paper focuses on mergers and acquisitions in the oil and gas industries, and lists the most important mergers in terms of transaction value for the period 1981-1997, and plots oil and gas mergers and acquisitions activity by sector and by major region. The mean operation indicator in 1998 in terms of reserves, production and refining capacity of the major companies are tabulated. The impact of the mergers on the oil and gas markets are examined, and issues concerning these mergers and acquisitions are explored. (UK)

Natural gas liquids: market outlook

International Nuclear Information System (INIS)

Heath, M.

1996-01-01

Future market outlook for natural gas liquids was discussed. It was shown that Canadian natural gas and natural gas liquid (NGL) production levels have experienced extraordinary growth over the past few years due to an increased U.S. demand for Canadian natural gas. Recent supply and demand studies have indicated that there will be growing surpluses of NGLs in Canada. By 1996, the majority of NGL surplus that is forecast to be available is ethane (64%), followed by propane (22%), butane (12%) and pentane plus (2%). Throughout the forecast period, the ratio of incremental ethane to the total NGL surplus, over and above forecast demand, was expected to continue to rise. The viability of producing and processing that ethane and transporting it to market, will be crucial. Development of a large ex-Alberta C2+ pipeline from Empress to Mont Belvieu under the reference case supply projection is a possibility, but only if total tariff and fractionation charge on the line is less than or equal to 10 US cents/USG (currently 16-22 US cents/USG). 11 figs

Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

Directory of Open Access Journals (Sweden)

Megan J Donahue

Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

ADVANCED GAS TURBINE SYSTEMS RESEARCH

Energy Technology Data Exchange (ETDEWEB)

Unknown

2002-04-01

The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

ADVANCED GAS TURBINE SYSTEMS RESEARCH

Energy Technology Data Exchange (ETDEWEB)

Unknown

2002-02-01

The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

Design and operation of gas-heated thermal pumping units

Energy Technology Data Exchange (ETDEWEB)

Rostek, H A [Ruhrgas A.G., Essen (Germany, F.R.)

1979-03-01

The first gas heat pump systems have been operated since spring 1977. These are applied in living houses, school, swimming pools, and sport places and administration buildings. The heating performance of these systems is 150-3800 kW. Two of these systems, one in a swimming pool and one in a house for several families are operating, each of them for one heating period. The operational experiences with these gas heat pumps are reported on, basing on measurement results. The experience gathered from the operation of gas heat pumps systems is applied to the planning of other plants. The development of a standardized gas heat pump-series is emphasized.

Radiation-pressure-driven sub-Keplerian rotation of the disc around the AGB star L2 Pup

Science.gov (United States)

Haworth, Thomas J.; Booth, Richard A.; Homan, Ward; Decin, Leen; Clarke, Cathie J.; Mohanty, Subhanjoy

2018-01-01

We study the sub-Keplerian rotation and dust content of the circumstellar material around the asymptotic giant branch (AGB) star L2 Puppis. We find that the thermal pressure gradient alone cannot explain the observed rotation profile. We find that there is a family of possible dust populations for which radiation pressure can drive the observed sub-Keplerian rotation. This set of solutions is further constrained by the spectral energy distribution (SED) of the system, and we find that a dust-to-gas mass ratio of ∼10-3 and a maximum grain size that decreases radially outwards can satisfy both the rotation curve and SED. These dust populations are dynamically tightly coupled to the gas azimuthally. However, grains larger than ∼ 0.5 μm are driven outwards radially by radiation pressure at velocities ∼5 km s-1, which implies a dust replenishment rate of ∼3 × 10-9 M⊙ yr-1. This replenishment rate is consistent with observational estimates to within uncertainties. Coupling between the radial motion of the dust and gas is weak and hence the gas does not share in this rapid outward motion. Overall, we conclude that radiation pressure is a capable and necessary mechanism to explain the observed rotation profile of L2 Pup, and offers other additional constraints on the dust properties.

Mexican demand for US natural gas

International Nuclear Information System (INIS)

Kanter, M.A.; Kier, P.H.

1993-09-01

This study describes the Mexican natural gas industry as it exists today and the factors that have shaped the evolution of the industry in the past or that are expected to influence its progress; it also projects production and use of natural gas and estimates the market for exports of natural gas from the United States to Mexico. The study looks ahead to two periods, a near term (1993--1995) and an intermediate term (1996--2000). The bases for estimates under two scenarios are described. Under the conservative scenario, exports of natural gas from the United States would decrease from the 1992 level of 250 million cubic feet per day (MMCF/d), would return to that level by 1995, and would reach about 980 MMCF/D by 2000. Under the more optimistic scenario, exports would decrease in 1993 and would recover and rise to about 360 MMCF/D in 1995 and to 1,920 MMCF/D in 2000

Mexican demand for US natural gas

Energy Technology Data Exchange (ETDEWEB)

Kanter, M.A.; Kier, P.H.

1993-09-01

This study describes the Mexican natural gas industry as it exists today and the factors that have shaped the evolution of the industry in the past or that are expected to influence its progress; it also projects production and use of natural gas and estimates the market for exports of natural gas from the United States to Mexico. The study looks ahead to two periods, a near term (1993--1995) and an intermediate term (1996--2000). The bases for estimates under two scenarios are described. Under the conservative scenario, exports of natural gas from the United States would decrease from the 1992 level of 250 million cubic feet per day (MMCF/d), would return to that level by 1995, and would reach about 980 MMCF/D by 2000. Under the more optimistic scenario, exports would decrease in 1993 and would recover and rise to about 360 MMCF/D in 1995 and to 1,920 MMCF/D in 2000.

FFTF fission gas monitor computer system

International Nuclear Information System (INIS)

Hubbard, J.A.

1987-01-01

The Fast Flux Test Facility (FFTF) is a liquid-metal-cooled test reactor located on the Hanford site. A dual computer system has been developed to monitor the reactor cover gas to detect and characterize any fuel or test pin fission gas releases. The system acquires gamma spectra data, identifies isotopes, calculates specific isotope and overall cover gas activity, presents control room alarms and displays, and records and prints data and analysis reports. The fission gas monitor system makes extensive use of commercially available hardware and software, providing a reliable and easily maintained system. The design provides extensive automation of previous manual operations, reducing the need for operator training and minimizing the potential for operator error. The dual nature of the system allows one monitor to be taken out of service for periodic tests or maintenance without interrupting the overall system functions. A built-in calibrated gamma source can be controlled by the computer, allowing the system to provide rapid system self tests and operational performance reports

Prospective of the market of Petroleum liquefied gas 2002-2011; Prospectiva del Mercado de Gas Licuado de Petroleo 2002-2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

The petroleum liquefied gas regulation (PLGR) establishes in it 8 Th Article that the Secretaria de Energia will draw up annually a prospective document about the Mexican market behavior of PL gas where its can be describing and analysing the necessities of the country in relation with this industry for an horizon of 10 years. Subjects such as: the panorama about the situation and perspectives of the international market of PL gas as well as the information at regional level of this fuel for 1990-2015 are treated. The main laws, regulations and arrangements of this industry, the evolution of the internal market of PL gas of 1995-2001 including prices which have been presented during this period, the expected evolution of the supply and demand of PL gas and the opportunities which exist in the industry in savings and efficient use of energy matter are presented. (Author)

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

Science.gov (United States)

Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

2017-08-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery

State and Territory Greenhouse Gas Emissions 2004

International Nuclear Information System (INIS)

2006-06-01

This document provides an overview of the latest available estimates of greenhouse gas emissions for Australia's States and Territories. Australia's total greenhouse gas emissions in 2004 amounted to 564.7 million tonnes. The State and Territory breakdown was: New South Wales: 158.7 million tonnes (Mt); Queensland: 158.5 Mt; Victoria: 123.0 Mt; Western Australia: 68.5 Mt; South Australia: 27.6 Mt; Northern Territory: 15.6 Mt; Tasmania: 10.7 Mt; ACT: 1.2 Mt. The summary of State and Territory inventories presented in this document reports estimates of greenhouse gas emissions for each State and Territory for the period 1990 to 2004. It is the first time that a complete annual time-series has been reported

Porous Silicon Structures as Optical Gas Sensors

Directory of Open Access Journals (Sweden)

Igor A. Levitsky

2015-08-01

Full Text Available We present a short review of recent progress in the field of optical gas sensors based on porous silicon (PSi and PSi composites, which are separate from PSi optochemical and biological sensors for a liquid medium. Different periodical and nonperiodical PSi photonic structures (bares, modified by functional groups or infiltrated with sensory polymers are described for gas sensing with an emphasis on the device specificity, sensitivity and stability to the environment. Special attention is paid to multiparametric sensing and sensor array platforms as effective trends for the improvement of analyte classification and quantification. Mechanisms of gas physical and chemical sorption inside PSi mesopores and pores of PSi functional composites are discussed.

Natural gas resources in Canada

International Nuclear Information System (INIS)

Meneley, R.A.

2001-01-01

Natural gas is an important component in many of the technologies aimed at reducing greenhouse gas emissions. In order to understand the role that natural gas can play, it is important to know how much may be present, where it is, when can it be accessed and at what cost. The Canadian Gas Potential Committee has completed its second report 'Natural Gas Potential in Canada - 2001' (CGPC, 2001). This comprehensive study of exploration plays in Canada addresses the two issues of 'how much may be present' and 'where is it'. The Report deals with both conventional gas and non-conventional gas. One hundred and seven Established Conventional Exploration Plays, where discoveries of gas exist, have been assessed in all of the sedimentary basins in Canada. In addition, where sufficient information was available, twelve Conceptual Exploration Plays, where no discoveries have been made, were assessed. Sixty-five other Conceptual Plays were described and qualitatively ranked. An experienced volunteer team of exploration professionals conducted assessments of undiscovered gas potential over a four-year period. The team used technical judgment, statistical techniques and a unique peer review process to make a comprehensive assessment of undiscovered gas potential and estimates of the size of individual undiscovered gas accumulations. The Committee assessed all gas in place in individual exploration plays. For Established Plays, estimates of Undiscovered Nominal Marketable Gas are based on the percentage of the gas in place that is marketable gas in the discovered pools in a play. Not all of the Nominal Marketable Gas will be available. Some underlies areas where exploration is not possible, such as parks, cities and other closed areas. Some will be held in gas pools that are too small to be economic and some of the pools will never be found. In some areas no production infrastructure will be available. Detailed studies of individual exploration plays and basins will be required

Kajian Bibliometrik Riset Minyak dan Gas Bumi Nasional 1990-2014

Directory of Open Access Journals (Sweden)

Himawanto Himawanto

2015-06-01

Abstract: High dependence of national income on oil and natural gas fueled production at the maximum level which results in oil and gas reserves dropped dramatically so that it appears response among researchers to find innovative methods or new concepts. In order to accommodate researchers to account for its innovative concept and disseminate to the public, Lemigas as a research center publishes the journal Scientific Contribution Oil and Gas. To know the main focus, insights and aspirations of active contributors, as well as the approach taken bibliometric research collaboration. The period 1990-2014 recorded oil and gas research amounted to 336 articles. The main focus of the increase in oil and gas reserves and production of the most studied up to 41.07%, followed by the research topic as much as 25.89% process aims to reduce dependence on oil. Research carried researchers from eight countries are in the six geographical region or three continents. According to the aspirations of insight 112 researchers from two continents contribute to produce the article, and partly repute global. As many as two to four more investigators affiliated from eight types of institutions in Asia, Europe, and the United States collaborated to produce 154 research products. For nearly three decades of fluctuating oil and gas research cooperation and the 2010-2014 period increased level of collaboration.

Intravitreal gas injection without vitrectomy for macular detachment associated with an optic disk pit.

Science.gov (United States)

Akiyama, Hideo; Shimoda, Yukitoshi; Fukuchi, Mariko; Kashima, Tomoyuki; Mayuzumi, Hideyasu; Shinohara, Yoichiro; Kishi, Shoji

2014-02-01

To evaluate the clinical outcomes after gas tamponade without vitrectomy for retinal detachment associated with an optic disk pit using optical coherence tomography. Intravitreal gas injection was performed on 8 consecutive patients (mean age, 35.0 years; range, 15-74 years) with unilateral macular detachment associated with an optic disk pit. A 0.3-mL injection of 100% sulfur hexafluoride 6 gas was carried out without an anterior chamber tap. Patients treated with gas injection were instructed to remain facedown for 5 days. Complete retinal reattachment after only gas tamponade was achieved in four out of eight eyes. The mean number of gas injections was 1.8. The mean best-corrected visual acuity before and after the treatment with gas tamponade was approximately 30/100 and 20/20, respectively. The period required for reattachment after final gas treatment was 12 months. There were no incidences of recurrence after complete reattachment by gas tamponade in any of the cases during the 94-month average follow-up period (range, 64-132 months). Gas tamponade appears to be an effective alternative method for macular detachment associated with an optic disk pit, even though the mechanisms of optic disk pit maculopathy are still unknown.

77 FR 69585 - Greenhouse Gas Reporting Program: Proposed Amendments and Confidentiality Determinations for...

Science.gov (United States)

2012-11-20

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 98 [EPA-HQ-OAR-2011-0028; FRL-9753-2] Greenhouse Gas... announcing an extension of the public comment period for the proposed rule titled ``Greenhouse Gas Reporting... [[Page 69586

Malaysian industry enters the gas era

International Nuclear Information System (INIS)

Buckman, David.

1992-01-01

Malaysia's petroleum industry is looking forward to an expansionary period until the end of the century, with the role of gas being greatly enhanced. The state oil firm Petronas sees increasing oil and gas reserves, making fuller use of abundant gas reserves, an exploration thrust into deepwater areas and the intensification of environmental protection as some of the points of emphasis in its current programme. The state firm president Tan Sri Datuk Azizan Zainul Abidin says that in the past few years a national economic growth rate of 8 percent has resulted in rising energy demand. Economic growth is projected to continue, so that an increase in power demand can be expected for the next few years. 'Fortunately, we are experiencing the same bullish trend in oil exploration and development,' he says. (author)

Flammable gas data evaluation. Progress report

International Nuclear Information System (INIS)

Whitney, P.D.; Meyer, P.A.; Miller, N.E.

1996-10-01

The Hanford Site is home to 177 large, underground nuclear waste storage tanks. Numerous safety and environmental concerns surround these tanks and their contents. One such concern is the propensity for the waste in these tanks to generate, retain, and periodically release flammable gases. This report documents some of the activities of the Flammable Gas Project Data Evaluation Task conducted for Westinghouse Hanford Company during fiscal year 1996. Described in this report are: (1) the results of examining the in-tank temperature measurements for insights into gas release behavior; (2) the preliminary results of examining the tank waste level measurements for insights into gas release behavior; and (3) an explanation for the observed hysteresis in the level/pressure measurements, a phenomenon observed earlier this year when high-frequency tank waste level measurements came on-line

Application of Fiscal Incentives for Development of East Natuna Gas Field for Long-Term National Natural Gas Demand

Directory of Open Access Journals (Sweden)

Marwan Batubara

2015-08-01

Full Text Available East Natuna gas field, which has proven reserves of 46 trillion cubic feet, is projected to meet long-term natural gas needs. However, CO2-content of the gas reserves reaches 71%, leading to expensive development costs. This research investigates the feasibility of the field based on several fiscal incentives. Firstly, gas supply-demand until year 2040 was analyzed. Then, based on the analysis, the field was developed using high CO2 gas separation technology to produce gas of 1300 MMSCFD in 2023, 2600 MMSCFD in 2031, and 3900 MMSCFD in 2039. Finally, the economic feasibility was assessed using cash flow analysis in accordance with Indonesia’s production sharing contract scheme. The results show that the supply-demand gap continues to increase and thus the development is urgently needed. The development cost is estimated around US$ 27.59 billion. The gas selling prices are assumed at US$ 8/MMBTU for wellhead, US$ 11/MMBTU for pipelines, and US$ 11/MMBTU for LNG. To achieve minimum IRR value of 12%, the government needs to offer incentives of 30-year contract period, profit sharing of 55%: 45%, first tranche petroleum to 10%, and tax holiday of 10 years. Toll fee for Natuna-Cirebon pipeline is US$ 2.3/MMBTU at IRR of 12.6%.

Integrating climate forecasts and natural gas supply information into a natural gas purchasing decision

Science.gov (United States)

Changnon, David; Ritsche, Michael; Elyea, Karen; Shelton, Steve; Schramm, Kevin

2000-09-01

This paper illustrates a key lesson related to most uses of long-range climate forecast information, namely that effective weather-related decision-making requires understanding and integration of weather information with other, often complex factors. Northern Illinois University's heating plant manager and staff meteorologist, along with a group of meteorology students, worked together to assess different types of available information that could be used in an autumn natural gas purchasing decision. Weather information assessed included the impact of ENSO events on winters in northern Illinois and the Climate Prediction Center's (CPC) long-range climate outlooks. Non-weather factors, such as the cost and available supplies of natural gas prior to the heating season, contribute to the complexity of the natural gas purchase decision. A decision tree was developed and it incorporated three parts: (a) natural gas supply levels, (b) the CPC long-lead climate outlooks for the region, and (c) an ENSO model developed for DeKalb. The results were used to decide in autumn whether to lock in a price or ride the market each winter. The decision tree was tested for the period 1995-99, and returned a cost-effective decision in three of the four winters.

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

International Nuclear Information System (INIS)

Mahan, R.

1998-01-01

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

Multiscale CT-Based Computational Modeling of Alveolar Gas Exchange during Artificial Lung Ventilation, Cluster (Biot and Periodic (Cheyne-Stokes Breathings and Bronchial Asthma Attack

Directory of Open Access Journals (Sweden)

Andrey Golov

2017-02-01

Full Text Available An airflow in the first four generations of the tracheobronchial tree was simulated by the 1D model of incompressible fluid flow through the network of the elastic tubes coupled with 0D models of lumped alveolar components, which aggregates parts of the alveolar volume and smaller airways, extended with convective transport model throughout the lung and alveolar components which were combined with the model of oxygen and carbon dioxide transport between the alveolar volume and the averaged blood compartment during pathological respiratory conditions. The novel features of this work are 1D reconstruction of the tracheobronchial tree structure on the basis of 3D segmentation of the computed tomography (CT data; 1D−0D coupling of the models of 1D bronchial tube and 0D alveolar components; and the alveolar gas exchange model. The results of our simulations include mechanical ventilation, breathing patterns of severely ill patients with the cluster (Biot and periodic (Cheyne-Stokes respirations and bronchial asthma attack. The suitability of the proposed mathematical model was validated. Carbon dioxide elimination efficiency was analyzed in all these cases. In the future, these results might be integrated into research and practical studies aimed to design cyberbiological systems for remote real-time monitoring, classification, prediction of breathing patterns and alveolar gas exchange for patients with breathing problems.

Impact of Alaskan gas subsidy

International Nuclear Information System (INIS)

George, R.R.

2002-01-01

This report provides the Government of the Northwest Territories (GNWT) with an assessment of the impact of the Alaska natural gas tax credit proposed and passed in the United States Senate energy bill. In particular, Purvin and Gertz evaluated the impact of the Alaskan gas subsidy on potential Mackenzie Delta/Beaufort Sea production as well as existing and future production from other areas including Western Canada, the Rocky Mountains in the United States, and the Gulf Coast. The mechanisms through which other producing areas are affected were described and the typical volumetric impact is presented using gas models developed by Purvin and Gertz. The GNWT wants to maximize the benefits of Arctic gas development for its constituents but believes that its interests will be negatively impacted by subsidized Alaskan gas which will be applied for the period beginning in 2010. The tax credit sets a floor price of $3.25 (US)/MMBtu. Purvin and Gertz concludes that the Alaskan gas subsidy would produce a misallocation of resources and distort the continental North American natural gas market. It would encourage over investment in Alaskan gas production because the credit works as a false signal to the privileged few that divert resources from higher value activities to lower value activities. The winners of the Alaskan gas subsidy would be Alaskan producers and the Alaskan economy. The losers would be other resource owners, producers, and American taxpayers because they would finance the subsidy through a tax credit mechanism. There would be an overall loss to the economy because of sub-optimal allocation of resources. In addition, producers in existing producing areas such as the Mackenzie Delta/Beaufort Sea region would face lower market prices as a result of the subsidy, thereby reducing their investments. It was concluded that the Alaskan gas subsidy is counterproductive from the perspective of a secure continental supply of natural gas. 1 tab., 2 figs

Suitability of selected free-gas and dissolved-gas sampling containers for carbon isotopic analysis.

Science.gov (United States)

Eby, P; Gibson, J J; Yi, Y

2015-07-15

Storage trials were conducted for 2 to 3 months using a hydrocarbon and carbon dioxide gas mixture with known carbon isotopic composition to simulate typical hold times for gas samples prior to isotopic analysis. A range of containers (both pierced and unpierced) was periodically sampled to test for δ(13)C isotopic fractionation. Seventeen containers were tested for free-gas storage (20°C, 1 atm pressure) and 7 containers were tested for dissolved-gas storage, the latter prepared by bubbling free gas through tap water until saturated (20°C, 1 atm) and then preserved to avoid biological activity by acidifying to pH 2 with phosphoric acid and stored in the dark at 5°C. Samples were extracted using valves or by piercing septa, and then introduced into an isotope ratio mass spectrometer for compound-specific δ(13)C measurements. For free gas, stainless steel canisters and crimp-top glass serum bottles with butyl septa were most effective at preventing isotopic fractionation (pierced and unpierced), whereas silicone and PTFE-butyl septa allowed significant isotopic fractionation. FlexFoil and Tedlar bags were found to be effective only for storage of up to 1 month. For dissolved gas, crimp-top glass serum bottles with butyl septa were again effective, whereas silicone and PTFE-butyl were not. FlexFoil bags were reliable for up to 2 months. Our results suggest a range of preferred containers as well as several that did not perform very well for isotopic analysis. Overall, the results help establish better QA/QC procedures to avoid isotopic fractionation when storing environmental gas samples. Recommended containers for air transportation include steel canisters and glass serum bottles with butyl septa (pierced and unpierced). Copyright © 2015 John Wiley & Sons, Ltd.

Hybrid continuum–molecular modelling of multiscale internal gas flows

International Nuclear Information System (INIS)

Patronis, Alexander; Lockerby, Duncan A.; Borg, Matthew K.; Reese, Jason M.

2013-01-01

We develop and apply an efficient multiscale method for simulating a large class of low-speed internal rarefied gas flows. The method is an extension of the hybrid atomistic–continuum approach proposed by Borg et al. (2013) [28] for the simulation of micro/nano flows of high-aspect ratio. The major new extensions are: (1) incorporation of fluid compressibility; (2) implementation using the direct simulation Monte Carlo (DSMC) method for dilute rarefied gas flows, and (3) application to a broader range of geometries, including periodic, non-periodic, pressure-driven, gravity-driven and shear-driven internal flows. The multiscale method is applied to micro-scale gas flows through a periodic converging–diverging channel (driven by an external acceleration) and a non-periodic channel with a bend (driven by a pressure difference), as well as the flow between two eccentric cylinders (with the inner rotating relative to the outer). In all these cases there exists a wide variation of Knudsen number within the geometries, as well as substantial compressibility despite the Mach number being very low. For validation purposes, our multiscale simulation results are compared to those obtained from full-scale DSMC simulations: very close agreement is obtained in all cases for all flow variables considered. Our multiscale simulation is an order of magnitude more computationally efficient than the full-scale DSMC for the first and second test cases, and two orders of magnitude more efficient for the third case

The Behaviour of Gas Bubble during Rest Period of Pulse-Activated Electrolysis Hydrogen Production

Directory of Open Access Journals (Sweden)

Vilasmongkolchai Thanet

2016-01-01

Full Text Available The pulse-activated electrolyzer has been developed and used for several years. With the capability of enhancing the efficiency of an electrolytic process and easy operation, this technique becomes an interesting process for hydrogen production. Unfortunately during electrolytic reaction, the creation of bubbles becomes a reaction inhibitor and consumes energy. This paper aims to study the proper rest period that gives the bubble free rise-off the solution without additional bubble created. The mathematical method and acoustic emission method were used for investigation of bubble’s rising velocity. The result shows that the variation of rest period on pulse-activated makes production efficiency enhanced. For the practicality of use and set control parameters, duty cycle and frequency were demonstrated instead of rest period.

Assessing the Greenhouse Gas Emissions from Natural Gas Fired Power Plants

Science.gov (United States)

Hajny, K. D.; Shepson, P. B.; Rudek, J.; Stirm, B. H.; Kaeser, R.; Stuff, A. A.

2017-12-01

Natural gas is often discussed as a "bridge fuel" to transition to renewable energy as it only produces 51% the amount of CO2 per unit energy as coal. This, coupled with rapid increases in production fueled by technological advances, has led to a near tripling of natural gas used for electricity generation since 2005. One concern with this idea of a "bridge fuel" is that methane, the primary component of natural gas, is itself a potent greenhouse gas with 28 and 84 times the global warming potential of CO2 based on mass over a 100 and 20 year period, respectively. Studies have estimated that leaks from the point of extraction to end use of 3.2% would offset the climate benefits of natural gas. Previous work from our group saw that 3 combined cycle power plants emitted unburned CH4 from the stacks and leaked additional CH4 from equipment on site, but total loss rates were still less than 2.2%. Using Purdue's Airborne Laboratory for Atmospheric Research (ALAR) we completed additional aircraft based mass balance experiments combined with passes directly over power plant stacks to expand on the previous study. In this work, we have measured at 12 additional natural gas fired power plants including a mix of operation types (baseload, peaking, intermediate) and firing methods (combined cycle, simple thermal, combustion turbine). We have also returned to the 3 plants previously sampled to reinvestigate emissions for each of those, to assess reproducibility of the results. Here we report the comparison of reported continuous emissions monitoring systems (CEMS) data for CO2 to our emission rates calculated from mass balance experiments, as well as a comparison of calculated CH4 emission rates to estimated emission rates based on the EPA emission factor of 1 g CH4/mmbtu natural gas and CEMS reported heat input. We will also discuss emissions from a coal-fired plant which has been sampled by the group in the past and has since converted to natural gas. Lastly, we discuss the

Periodic safety review of the HTR-10 safety analysis

International Nuclear Information System (INIS)

Chen Fubing; Zheng Yanhua; Shi Lei; Li Fu

2015-01-01

Designed by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University, the 10 MW High Temperature Gas-cooled Reactor-Test Module (HTR-10) is the first modular High Temperature Gas-cooled Reactor (HTGR) in China. According to the nuclear safety regulations of China, the periodic safety review (PSR) of the HTR-10 was initiated by INET after approved by the National Nuclear Safety Administration (NNSA) of China. Safety analysis of the HTR-10 is one of the key safety factors of the PSR. In this paper, the main contents in the review of safety analysis are summarized; meanwhile, the internal evaluation on the review results is presented by INET. (authors)

Economic evaluation of biogas and natural gas co-firing in gas turbine combined heat and power systems

International Nuclear Information System (INIS)

Kang, Jun Young; Kang, Do Won; Kim, Tong Seop; Hur, Kwang Beom

2014-01-01

This study investigated the economics of co-firing biogas and natural gas within a small gas turbine combined heat and power (CHP) plant. The thermodynamic performance of the CHP plant was calculated with varying gas mixing ratios, forming the basis for the economic analysis. A cost balance equation was used to calculate the costs of electricity and heat. The methodology was validated, and parametric analyses were used to investigate the influence of gas mixing ratio and heat sales ratio on the costs of electricity and heat. The cost of electricity generation from the CHP plant was compared to that of a central combined cycle power plant, and an economical gas mixing ratio range were suggested for various heat sales ratios. It was revealed that the effect of the heat sales ratio on the cost of electricity becomes greater as the proportion of natural gas is increased. It was also demonstrated that the economic return from the installation of CHP systems is substantially affected by the gas mixing ratio and heat sales ratio. Sensitivity analysis showed that influence of economic factors on the CHP plant is greater when a higher proportion of natural gas is used. - Highlights: • An appropriate method to calculate the costs of electricity (COE) and heat (COH) was established. • Both COE and COH increase with increasing natural gas mixing ratio and decreasing heat sales ratio. • The effect of the heat sales ratio on the COE becomes greater as the mixing ratio increases. • The payback period is considerably dependent on the mixing ratio and heat sales ratio

Experimental research on coalbed gas drainage effect and economy of long directional borehole in roof

Science.gov (United States)

Yang, Huiming; Hu, Liangping

2017-05-01

In order to study the coalbed gas drainage effect and economy of long directional roof borehole, 2 boreholes were laid out in Xinji No. 2 mine to analyze its gas drainage and investment costs comparing with high position roof borehole and high position roof roadway. The result indicates that the long directional roof borehole save investment by 44.8% and shorten the construction period by 30%, comparing with high position roof roadway for controlling gas in the working face. Investment slightly less and shorten the construction period by 47.5%, comparing with the roof high position borehole. Therefore, the method of the long directional roof borehole to drain coalbed gas in working face is the most cost-effective.

Gas production potential of disperse low-saturation hydrate accumulations in oceanic sediments

International Nuclear Information System (INIS)

Moridis, George J.; Sloan, E. Dendy

2007-01-01

In this paper, we evaluate the gas production potential of disperse, low-saturation (S H H hydrate-bearing sediments subject to depressurization-induced dissociation over a 10-year production period. We investigate the sensitivity of items (a)-(c) to the following hydraulic properties, reservoir conditions, and operational parameters: intrinsic permeability, porosity, pressure, temperature, hydrate saturation, and constant pressure at which the production well is kept. The results of this study indicate that, despite wide variations in the aforementioned parameters (covering the entire spectrum of such deposits), gas production is very limited, never exceeding a few thousand cubic meters of gas during the 10-year production period. Such low production volumes are orders of magnitude below commonly accepted standards of economic viability, and are further burdened with very unfavorable gas-to-water ratios. The unequivocal conclusion from this study is that disperse, low-S H hydrate accumulations in oceanic sediments are not promising targets for gas production by means of depressurization-induced dissociation, and resources for early hydrate exploitation should be focused elsewhere

Gas-cooled reactor technology: a bibliography

International Nuclear Information System (INIS)

Raleigh, H.D.

1981-09-01

Included are 3358 citations on gas-cooled reactor technology contained in the DOE Energy Data Base for the period January 1978 through June 1981. The citations include reports, journal articles, books, conference papers, patents, and monographs. Corporate, Personal Author, Subject, Contract Number, and Report Number Indexes are provided

A Fine-Tuned MOF for Gas and Vapor Separation: A Multipurpose Adsorbent for Acid Gas Removal, Dehydration, and BTX Sieving

KAUST Repository

Haja Mohideen, Mohamed Infas; Pillai, Renjith S.; Adil, Karim; Bhatt, Prashant; Belmabkhout, Youssef; Shkurenko, Aleksander; Maurin, Guillaume; Eddaoudi, Mohamed

2017-01-01

Summary The development of highly stable separation agents is recognized as a decisive step toward the successful deployment of energy-efficient and cost-effective separation processes. Here, we report the synthesis and construction of a metal-organic framework (MOF), kag-MOF-1, that has adequate structural and chemical features and affords a stable adsorbent with unique and appropriate adsorption properties for gas processing akin to acid gas removal, dehydration, and benzene-toluene-xylene (BTX) sieving. A combination of X-ray diffraction experiments, adsorption studies, mixed-gas breakthrough adsorption column testing, calorimetric measurements, and molecular simulations corroborated the exceptional separation performance of kag-MOF-1 and its prospective use as a multifunctional adsorbent. The unique adsorption properties of kag-MOF-1, resulting from the contracted pore system with aligned periodic array of exposed functionalities, attest to the prominence of this new generation of ultra-microporous material as a prospective practical adsorbent toward cost-effective and more simplified gas and vapor processing flowcharts for natural gas upgrading and flue gas scrubbing.

A Fine-Tuned MOF for Gas and Vapor Separation: A Multipurpose Adsorbent for Acid Gas Removal, Dehydration, and BTX Sieving

KAUST Repository

Haja Mohideen, Mohamed Infas

2017-10-19

Summary The development of highly stable separation agents is recognized as a decisive step toward the successful deployment of energy-efficient and cost-effective separation processes. Here, we report the synthesis and construction of a metal-organic framework (MOF), kag-MOF-1, that has adequate structural and chemical features and affords a stable adsorbent with unique and appropriate adsorption properties for gas processing akin to acid gas removal, dehydration, and benzene-toluene-xylene (BTX) sieving. A combination of X-ray diffraction experiments, adsorption studies, mixed-gas breakthrough adsorption column testing, calorimetric measurements, and molecular simulations corroborated the exceptional separation performance of kag-MOF-1 and its prospective use as a multifunctional adsorbent. The unique adsorption properties of kag-MOF-1, resulting from the contracted pore system with aligned periodic array of exposed functionalities, attest to the prominence of this new generation of ultra-microporous material as a prospective practical adsorbent toward cost-effective and more simplified gas and vapor processing flowcharts for natural gas upgrading and flue gas scrubbing.

New generation enrichment monitoring technology for gas centrifuge enrichment plants

International Nuclear Information System (INIS)

Ianakiev, Kiril D.; Alexandrov, Boian S.; Boyer, Brian D.; Hill, Thomas R.; Macarthur, Duncan W.; Marks, Thomas; Moss, Calvin E.; Sheppard, Gregory A.; Swinhoe, Martyn T.

2008-01-01

The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF 6 containing low enriched (approximately 4% 235 U) and highly enriched (above 20% 235 U) uranium. This instrument used the 22-keV line from a 109 Cd source as a transmission source to achieve a high sensitivity to the UF 6 gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF 6 product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

The Ikhil Gas Project: developing the first commercial natural gas project north of the Arctic Circle

Energy Technology Data Exchange (ETDEWEB)

Malin, G. [AltaGas Services Inc., AB (Canada)

2001-07-01

Development of the Ikhil Natural Gas Project by the Inuvialuit Petroleum Corporation in partnership with Enbridge and AltaGas Services are described in a step-by-step fashion. A minimum of 11 Bcf of recoverable natural gas reserves have been established to date. The Northwest Territories Power Corporation is committed under a 15-year take-or-pay contract to take the gas, and the Town of Inuvik also has a franchise agreement with the project owners for a 15-year period. Challenges faced and overcome in adapting to the regulatory process, the engineering problems that required special solutions (e.g. ice/snow roads, gravel pad to support wellhead and production facilities, reducing temperature of gas to avoid disturbing the permafrost, sand-padding pipeline to supplement high ice/content material), converting a diesel town to a natural gas town, and installing an underground distribution system in ground that is constantly shifting due to permafrost, are some of the examples discussed. Benefits accruing to local people and businesses during construction and the production phases of the project are described, along with details of an assessment and discussion of lessons learned after two years of operation. Overall, the project is considered to have been an engineering success. Financially, it is too early to judge, but it is expected that with economic development in Inuvik taking off, demand for natural gas and electricity will develop and justify the confidence of the developers.

Natural gas productive capacity for the lower 48 states, 1982--1993

International Nuclear Information System (INIS)

1993-01-01

The purpose of this report is to analyze monthly natural gas wellhead productive capacity and project this capacity for 1992 and 1993, based upon historical production data through 1991. Productive capacity is the volume of gas that can be produced from a well, reservoir, or field during a given period of time against a certain wellhead back-pressure under actual reservoir conditions excluding restrictions imposed by pipeline capacity, contracts, or regulatory bodies. For decades, natural gas supplies and productive capacity have been adequate, although in the 1970's the capacity surplus was small because of market structure (both interstate and intrastate), increasing demand, and insufficient drilling. In the early 1980's, lower demand together with increased drilling led to a large surplus of natural gas capacity. After 1986, this large surplus began to decline as demand for gas increased, gas prices dropped, and gas well completions dropped sharply. In late December 1989, this surplus decline, accompanied by exceptionally high demand and temporary weather-related production losses, led to concerns about the adequacy of monthly productive capacity for natural gas. This study indicates that monthly productive capacity will drop sharply during the 1992-1993 period. In the low gas price, low drilling case, gas productive capacity and estimated production demand will be roughly equal in December 1993. In base and high drilling cases, monthly productive capacity should be able to meet normal production demands through 1993 in the lower 48 States. Exceptionally high peak-day or peak-week production demand might not be met because of physical limitations. Beyond 1993, as the capacity of currently producing wells declines, a sufficient number of wells and/or imports must be added each year in order to ensure an adequate gas supply

Geologic framework influences on the geomorphology of an anthropogenically modified barrier island: Assessment of dune/beach changes at Fire Island, New York

Science.gov (United States)

Lentz, E.E.; Hapke, C.J.

2011-01-01

Antecedent geology plays a crucial role in determining the inner-shelf, nearshore, and onshore geomorphology observed in coastal systems. However, the influence of the geologic framework on a system is difficult to extract when evaluating responses to changes due to storms and anthropogenic modifications, and few studies have quantified the potential for these influences in dune/beach environments. This study evaluates topographic change to the dune/beach system at Fire Island, New York over a ten year period (1998-2008) at two sites representing eastern and western reaches of the island where morphology has been shown to vary. The sites are situated along swaths of coast eroding differentially and where the inner shelf geologic framework differs substantially. Fewer large storms occurred in the first half of the study period, compared with the later part of the study period which includes several severe and prolonged extratropical storms. Additionally, a major beach replenishment project was conducted at one of the study sites. Topographic data from LiDAR and RTK GPS surveys are used to construct high-resolution 3D surfaces, which are used to determine volumetric change and to extract 2D alongshore features and profiles for analysis. The study sites help to further characterize morphologic differences between eastern and western reaches of the island. The western site displays higher sand volumes, lower dunes, and a lower gradient profile slope when compared with the eastern site. In addition to these fundamental morphologic differences, the two sites also differ significantly in their response to coastal storms and in the fact that their replenishment histories are different. The replenished areas show reduced vulnerability to storms through minimal volume loss and shoreline accretion that should be considered when evaluating the response of replenished areas to episodic events. We propose that site-specific differences evident throughout the study period can be

Magma replenishment and volcanic unrest inferred from the analysis of VT micro-seismicity and seismic velocity changes at Piton de la Fournaise Volcano

Science.gov (United States)

Brenguier, F.; Rivemale, E.; Clarke, D. S.; Schmid, A.; Got, J.; Battaglia, J.; Taisne, B.; Staudacher, T.; Peltier, A.; Shapiro, N. M.; Tait, S.; Ferrazzini, V.; Di Muro, A.

2011-12-01

Piton de la Fournaise volcano (PdF) is among the most active basaltic volcanoes worldwide with more than one eruption per year on average. Also, PdF is densely instrumented with short-period and broad-band seismometers as well as with GPS receivers. Continuous seismic waveforms are available from 1999. Piton de la Fournaise volcano has a moderate inter-eruptive seismic activity with an average of five detected Volcano-Tectonic (VT) earthquakes per day with magnitudes ranging from 0.5 to 3.5. These earthquakes are shallow and located about 2.5 kilometers beneath the edifice surface. Volcanic unrest is captured on average a few weeks before eruptions by measurements of increased VT seismicity rate, inflation of the edifice summit, and decreased seismic velocities from correlations of seismic noise. Eruptions are usually preceded by seismic swarms of VT earthquakes. Recently, almost 50 % of seismic swarms were not followed by eruptions. Within this work, we aim to gather results from different groups of the UnderVolc research project in order to better understand the processes of deep magma transfer, volcanic unrest, and pre-eruptive magma transport initiation. Among our results, we show that the period 1999-2003 was characterized by a long-term increase of VT seismicity rate coupled with a long-term decrease of seismic velocities. These observations could indicate a long-term replenishment of the magma storage area. The relocation of ten years of inter-eruptive micro-seismicity shows a narrow (~300 m long) sub-vertical fault zone thus indicating a conduit rather than an extended magma reservoir as the shallow magma feeder system. Also, we focus on the processes of short-term volcanic unrest and prove that magma intrusions within the edifice leading to eruptions activate specific VT earthquakes that are distinct from magma intrusions that do not lead to eruptions. We thus propose that, among the different pathways of magma transport within the edifice, only one will

Market prospective of natural gas 2010-2025; Prospectiva del mercado de gas natural 2010-2025

Energy Technology Data Exchange (ETDEWEB)

Diaz Bautista, Alejandro; Doniz Gonzalez, Virginia; Navarrete Barbosa, Juan Ignacio [Secretaria de Energia, Mexico, D.F. (Mexico)

2010-07-01

The Ministry of Energy, in compliance to Article 109 of the Natural Gas Regulations, publishes the Prospective natural gas market 2010-2025, which contains the most current information about the historical evolution and growth prospects of the domestic market country's natural gas and its role in the international context. This foresight is attached to the lines of action established in the National Energy Strategy, ratified by Congress in April 2010 in regard to strengthening the transportation infrastructure of natural gas, in order to ensure the supply of this fuel, therefore remains congruence with the instruments of power sector planning. The first one concerns the international panorama of natural gas in the different producing and consuming regions around the world. Chapter two provides a current perspective of those actions in the sector within the regulatory framework for natural gas in Mexico. The third chapter details the issues that occurred in the natural gas market during the period 1999-2009 and the fourth chapter discusses the expected evolution of demand and domestic supply of natural gas by 2025. [Spanish] La Secretaria de Energia, en el cumplimiento al Articulo 109 del Reglamento de Gas Natural, publica la Prospectiva del mercado de gas natural 2010-2025, la cual contiene la informacion mas actualizada acerca de la evolucion historica y las expectativas de crecimiento del mercado interno de gas natural del pais y su papel en el contexto internacional. Esta Prospectiva se apega a las lineas de accion establecidas en la Estrategia Nacional de Energia, ratificada por el Congreso en abril de 2010, en lo relativo a fortalecer la infraestructura de transporte de gas natural, con el fin de asegurar el suministro de este combustible, por lo cual se mantiene congruencia con los instrumentos de planeacion del sector energetico. La Prospectiva esta integrada por cuatro capitulos. El primero se refiere al panorama internacional del gas natural en las

Technologies applied to wells producing gas in Bolivia; Tecnologias aplicadas aos pocos produtores de gas em Bolivia

Energy Technology Data Exchange (ETDEWEB)

Nobrega, Fernando R.B. [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Carrillo, Marco A.; Barrerro, Dennys A. [PETROBRAS Bolivia S.A., La Paz (Bolivia)

2012-07-01

The This paper seeks to highlight the engineering, lessons learned and topics for improvement of the technologies used in gas wells drilled between November 2008 and October 2011 in an environment of Bolivian' subandino. Among technologies employed and commented hereunder has the drilling gas reservoirs in near balance using a dual phase fluid, with nitrogen; carrying out multilateral wells equipped with intelligent completion in such environment; as well as other technologies presented herein. This document was prepared on drilling operations performed in SAL-15, SAL-17, SBLSBL- 7 and SBL-8, comprising the period from November 2008 to October 2011. (author)

Trans-Caspian gas pipeline feasibility study. Volume 3

International Nuclear Information System (INIS)

1999-01-01

This study, conducted by Enron Engineering and Construction Company, was funded by the US Trade and Development Agency. The study provides detailed information concerning natural gas demand in Turkey and Southern Europe. The purpose of the study is to estimate the rate at which new gas can be absorbed in the Turkish market and be re-exported to the markets in Europe, as well as to forecast Turkish natural gas demand for the period up to 2020. The study also evaluates gas demand and pricing for the market in the 2002--2005 time frame. This is Volume 3 of a 3-volume report, and it is divided into the following sections: (1) Executive Summary; (2) Task C: Technical Feasibility and Preliminary Design; (3) Task F: Project Implementation Strategy

Investment and uncertainty in the international oil and gas industry

International Nuclear Information System (INIS)

Mohn, Klaus; Misund, Baard

2009-01-01

The standard theory of irreversible investments and real options suggests a negative relation between investment and uncertainty. Richer models with compound option structures open for a positive relationship. This paper presents a micro-econometric study of corporate investment and uncertainty in a period of market turbulence and restructuring in the international oil and gas industry. Based on data for 115 companies over the period 1992-2005, we estimate four different specifications of the q model of investment, with robust results for the uncertainty variables. The estimated models suggest that macroeconomic uncertainty creates a bottleneck for oil and gas investment and production, whereas industry-specific uncertainty has a stimulating effect. (author)

Russians and Ukrainians plan new gas line

International Nuclear Information System (INIS)

TREND

2003-01-01

Paper deals with the building of new gas line between Russia and the Ukraine. In September 2003 Gazprom and Naftohaz Ukraine signed protocol about conditions of Russian gas transit through Ukrainian area for 2004. There is guaranteed quantity of transported gas on the level of 127,8 billions cubic meters by Russian side, 110 billions of it should next lead to Europe. Treaty refills long-term contract between Naftohaz and Gazprom about gas transit through Ukraine for period 2003-2013. Both countries and its companies plan to accept particular capital decision about building of new gas line Novopskov-Uzgorod till end of this year, which will be parallel with gas line Soyuz. It will allow to enlarge transportation system capacity by 28 billion cubic meters. Construction of about 1600 km long ducting system will require 1.6 billion USD by annual capacity about 15 billion cubic meters. If capacity would be doubled by construction of another compressor stations, capital expenses rise to 2.2 billions USD. It can be completely built in 7 years. Its linear part with one compressor can be already built in 3 years. Slovensky Plynarensky Podnik (SPP) would certainly have advantages from possible realisation of new gas line and from consequential transit increase. (Author)

Assessment of South Pars Gas Field Subsidence Due To Gas Withdrawal

Directory of Open Access Journals (Sweden)

Akbar Ghazifard

2014-12-01

Full Text Available Withdrawal of oil and gas from reservoirs causes a decrease in pore pressure and an increase in effective stress which results to a reservoir compaction. Reservoir compaction will result in surface subsidence through the elastic response of the subsurface. Usually in order to determine the subsidence above a hydrocarbon field, the reservoir compaction must be first calculated and then the effect of this compaction on the surface should be modeled. The use of the uniaxial compaction theory is more prevalent and an accepted method for determining the amount of reservoir compaction. But despite of the reservoir compaction calculation method, there are many methods with different advantages and shortcomings for modeling of surface subsidence. In this study, a simple analytical method and semi‌-analytical methods (AEsubs software were used for modeling of the surface subsidence of the South Pars gas field at the end of the production period.

Gas composition of sludge residue profiles in a sludge treatment reed bed between loadings.

Science.gov (United States)

Larsen, Julie D; Nielsen, Steen M; Scheutz, Charlotte

2017-11-01

Treatment of sludge in sludge treatment reed bed systems includes dewatering and mineralization. The mineralization process, which is driven by microorganisms, produces different gas species as by-products. The pore space composition of the gas species provides useful information on the biological processes occurring in the sludge residue. In this study, we measured the change in composition of gas species in the pore space at different depth levels in vertical sludge residue profiles during a resting period of 32 days. The gas composition of the pore space in the sludge residue changed during the resting period. As the resting period proceeded, atmospheric air re-entered the pore space at all depth levels. The methane (CH 4 ) concentration was at its highest during the first part of the resting period, and then declined as the sludge residue became more dewatered and thereby aerated. In the pore space, the concentration of CH 4 often exceeded the concentration of carbon dioxide (CO 2 ). However, the total emission of CO 2 from the surface of the sludge residue exceeded the total emission of CH 4 , suggesting that CO 2 was mainly produced in the layer of newly applied sludge and/or that CO 2 was emitted from the sludge residue more readily compared to CH 4 .

Transition of RF internal antenna plasma by gas control

Energy Technology Data Exchange (ETDEWEB)

Hamajima, Takafumi; Yamauchi, Toshihiko; Kobayashi, Seiji; Hiruta, Toshihito; Kanno, Yoshinori [Advanced Institute of Industrial Technology, 1-10-40 HigashiOhi, Shinagawa-ku, Tokyo, 140-0011 (Japan); Japan Atomic Energy Agency, 2-4 Tokai-mura, Naka-gun, Ibaraki-ken, 319-1195 (Japan)

2012-07-11

The transition between the capacitively coupled plasma (CCP) and the inductively coupled plasma (ICP) was investigated with the internal radio frequency (RF) multi-turn antenna. The transition between them showed the hysteresis curve. The radiation power and the period of the self-pulse mode became small in proportion to the gas pressure. It was found that the ICP transition occurred by decreasing the gas pressure from 400 Pa.

EIA sees US gas grid meeting demand in 2000

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that interstate natural gas pipelines should be able to meet record US natural gas demand by 2000, Energy Information Administration predicts in a new study. The EIA study examined the capacity of 42 long lines, average utilization of the pipeline grid, and recently completed or planned capacity expansions. EIA the significant additional volumes could be transported into some major consuming areas during off-peak periods

Conversion of hot coke oven gas into light fuel gas over Ni/Al{sub 2}O{sub 3} catalyst

Energy Technology Data Exchange (ETDEWEB)

Li, L.Y.; Morishita, K.; Takarada, T. [Gunma University, Gunma (Japan). Dept. of Biology & Chemical Engineering

2006-04-15

Conversion of hot coke oven gas (COG, containing tarry material) into light fuel gas over a Ni/Al{sub 2}O{sub 3} catalyst was studied. Laboratory scale tests were carried out in a two-stage fixed-bed reactor at ambient pressure. The nickel catalyst promoted the hydropyrolysis reaction of tarry materials. High yields of total product gas and methane were obtained at high hydrogen concentrations. If the hydrogen supply was adequate for hydropyrolysis of the tarry material, conversion of coal volatiles was high, at more than 95% on carbon balance, even with a gas residence time as short as 0.15 s in the catalyst bed. The product gas yield depended on catalytic temperature. At 923 K, the maximum conversion of coal volatiles into the light gas was achieved at 95.0% on carbon balance, with methane 86.7 vol% of the carbonaceous gas product. Although carbon deposits deactivated the catalyst after a long period of use, the catalyst could be regenerated by treatment with oxygen at 800 K, providing high activity in subsequent decomposition of tarry material. The influence of sulphide on the tarry material decomposition reaction was small even in a 2000 ppm H{sub 2}S atmosphere.

Emgas pioneers gas conditioning by humidification

Energy Technology Data Exchange (ETDEWEB)

de Winton, C

1975-03-01

As a first solution to any problems of serious joint leaking in low- and medium-pressure distribution networks, East Midlands Gas is using gas conditioning by steam or water injection and/or oil fogging. The project has been conceived on a sufficiently large scale to take in the whole area of supply; plans call for completion over a period of 7 yr. Emgas has based its humidification process on a positive control system, first and foremost to avoid certain serious pitfalls which can befall the casual injection of steam or water into a gas main. The control system used has been built around the Foxboro Dewcel, a thin-walled metal socket covered with a woven glass tape impregnated with lithium chloride. A 25-V ac source is connected to a pair of gold wires wound around the tape.

Analysis of gob gas venthole production performances for strata gas control in longwall mining.

Science.gov (United States)

Karacan, C Özgen

2015-10-01

Longwall mining of coal seams affects a large area of overburden by deforming it and creating stress-relief fractures, as well as bedding plane separations, as the mining face progresses. Stress-relief fractures and bedding plane separations are recognized as major pathways for gas migration from gas-bearing strata into sealed and active areas of the mines. In order for strata gas not to enter and inundate the ventilation system of a mine, gob gas ventholes (GGVs) can be used as a methane control measure. The aim of this paper is to analyze production performances of GGVs drilled over a longwall panel. These boreholes were drilled to control methane emissions from the Pratt group of coals due to stress-relief fracturing and bedding plane separations into a longwall mine operating in the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama. During the course of the study, Pratt coal's reservoir properties were integrated with production data of the GGVs. These data were analyzed by using material balance techniques to estimate radius of influence of GGVs, gas-in-place and coal pressures, as well as their variations during mining. The results show that the GGVs drilled to extract gas from the stress-relief zone of the Pratt coal interval is highly effective in removing gas from the Upper Pottsville Formation. The radii of influence of the GGVs were in the order of 330-380 m, exceeding the widths of the panels, due to bedding plane separations and stress relieved by fracturing. Material balance analyses indicated that the initial pressure of the Pratt coals, which was around 648 KPa when longwall mining started, decreased to approximately 150 KPa as the result of strata fracturing and production of released gas. Approximately 70% of the initial gas-in-place within the area of influence of the GGVs was captured during a period of one year.

Gas centrifuge bibliography 1983-1986

International Nuclear Information System (INIS)

Lowe, G.E.; McLeod, D.F.; Roberts, P.

1987-03-01

A bibliography is presented of the gas centrifuge literature published from 1983-1986 inclusive. It supplements PG Information Series 25(CA), BNFL Information Series 15(CA), BNFL Information Series 23 (CA), and BNFL Information Series 27(CA), which together cover the period 1895-1982. The main arrangement is chronological and there are author, report number, and subject indexes. (U.K.)

Gas utilization in the Tokamak Fusion Test Reactor neutral beam injectors

International Nuclear Information System (INIS)

Kamperschroer, J.H.; Gammel, G.M.; Kugel, H.W.; Grisham, L.R.; Stevenson, T.N.; von Halle, A.; Williams, M.D.; Jones, T.T.C.

1989-01-01

Measurements of gas utilization were performed using hydrogen and deuterium beams in the Tokamak Fusion Test Reactor (TFTR) neutral beam test beamline to study the feasibility of operating tritium beams with existing ion sources under conditions of minimal tritium consumption. (i) It was found that the fraction of gas molecules introduced into the TFTR long-pulse ion sources that are converted to extracted ions (i.e., the ion source gas efficiency) was higher than with previous short-pulse sources. Gas efficiencies were studied over the range 33%--55%, and its effect on neutralization of the extracted ions was studied. At the high end of the gas efficiency range, the neutral fraction of the beam fell below that predicted from room-temperature molecular gas flow (similar to observations at the Joint European Torus). (ii) Beam isotope change studies were performed. No extracted hydrogen ions were observed in the first deuterium beam following a working gas change from H 2 to D 2 . There was no arc conditioning or gas injection preceding the first beam extraction attempt. (iii) Experiments were also performed to determine the reliability of ion source operation during the long waiting periods between pulses that are anticipated during tritium operation. It was found that an ion source conditioned to 120 kV could produce a clean beam pulse after a waiting period of 14 h by preceding the beam extraction with several acceleration voltage/filament warm-up pulses. It can be concluded that the operation of up to six ion sources on tritium gas should be compatible with on-site inventory restrictions established for D--T, Q = 1 experiments on TFTR

Enron sees major increases in U.S. gas supply, demand

International Nuclear Information System (INIS)

Carson, M.M.; Stram, B.

1991-01-01

Enron Corp., Houston, in an extensive study of U.S. natural-gas supply and demand through the year 2000, has found that the U.S. gas-resource base is 1,200 tcf. Despite current weaknesses in natural-gas prices, demand growth will be strong although affected by oil-price assumptions. This paper reports on highlights in the areas of reserves and production which include gains in both categories in the Rockies/Wyoming, San Juan basin, and Norphlet trends (offshore Alabama). The Midcontinent/Hugoton area exhibits reserve declines in a period of flat production. In the U.S. Gulf Coast (USGC) offshore, both production and reserves decline over the forecast period. These projections are derived from a base-case price of $4.07/MMBTU by 2000. U.S. gas production exhibits a production decline in a low oil-price case from 19 to 16.4 tcf by 2000, if prices are 30% below the base case, that is, $2.93/MMBTU. Gains in commercial gas use are strong under either scenario of a base oil price of $29.80 in 1990 dollars in the year 2000 or a low oil price of $20.50 in 1990 dollars in 2000. Demand for natural gas for power generation grows as much as 1.5 tcf by 2000 in the Enron base case and by 300 bcf by 2000 in the low crude-oil price case

Argon cover gas purity control on LMFBR

Energy Technology Data Exchange (ETDEWEB)

Maeda, Hiroshi; Kobayashi, Takayoshi [PNC (Japan); Ishiyama, Satoshi [Toshiba (Japan); Motonaga, Tetsuji [Hitachi (Japan)

1987-07-01

Various control methods on chemical impurities and radioactive materials (fission products) in the primary argon gas of LMFBRs' have been studied based on experiences in Joyo and results of research and development. These results are reflected on MONJU design. On-line gas chromatographs are installed both in the Primary and in the Secondary Argon Gas Systems in JOYO. Also, chemical analysis has been done by batch sampling in JOYO. Though the rise of impurity concentration had been measured after periodical fuel exchange operation, impurity concentration has been controlled sufficiently under target control limits. In MONJU detailed design, the Rare Gas Removal and Recovery System which consisted of cryogenic distillation equipment had been eliminated and the capacity of Charcoal Beds in the Primary Argon Gas System has been improved to keep the concentration of radioactive materials sufficient low levels. The necessity to control the impurities in fresh argon gas which is supplied to the Primary Argon Gas System is now considered to keep the concentration of Kr and Xe isotopes in specified level, because their isotopes may make background rise for the Tagging Gas Failed Fuel Detection and Location System. Based on various investigations performed on sodium vapor trapping to obtain its detailed characteristics, design specifications and operating conditions of MONJU's Vapor Traps have been decided. To keep the level of radioactivity in gaseous effluents to the environment as low as reasonably achievable, the following means are now adopted in MONJU: the Primary Argon Gas System is composed of a closed recirculating path, but the exhaust gas discharged has different path after the Charcoal Beds; fresh argon gas is blown down to prevent Primary Argon Gas from releasing to the circumference during opening of the primary argon gas boundary, such as fuel exchange operations. (author)

Pluri annual indicative plan of the investments in the gas sector

International Nuclear Information System (INIS)

2007-03-01

This indicative plan constitutes the first report to the Parliament. It is a prospective document for the period 2006-2015 containing: a forecast of the gas demand increase, a description of main investments decided in matter of gas infrastructures, a diagnostic concerning the adequation between the supplying capacities in natural gas and the national needs, a series of recommendations on the State tools to guarantee the national supplying security and on the investment. The four parts deal with the stakes and perspectives of the national natural gas supplying, the demand evolution, the offer evolution and the equilibrium offer. (A.L.B.)

Transient Analysis and Design Improvement of a Gas Turbine Rotor Based on Thermal-Mechanical Method

Directory of Open Access Journals (Sweden)

Yang Liu

2018-01-01

Full Text Available The rotor is the core component of a gas turbine, and more than 80% of the failures in gas turbines occur in the rotor system, especially during the start-up period. Therefore, the safety assessment of the rotor during the start-up period is essential for the design of the gas turbine. In this paper, the transient equivalent stress of a gas turbine rotor under the cold start-up condition is investigated and the novel tie rod structure is introduced to reduce the equivalent stress. Firstly, a three-dimensional finite element model of the gas turbine rotor is built, and nonlinear contact behaviors such as friction are taken into account. Secondly, the convective heat transfer coefficients of the gas turbine rotor under the cold start-up condition are calculated using thermal dynamic theory. The transient analysis of the gas turbine rotor is conducted considering the thermal load, the centrifugal load, and the pretightening force. The temperature and stress distributions of the rotor under the cold start-up condition are shown in detail. In particular, the generation mechanism of maximum equivalent stress for tie rods and the change tendency of the pretightening force are illustrated in detail. The tie rod holes of the rear shaft and the turbine tie rod are the dangerous locations during the start-up period. Finally, a novel tie rod is proposed to reduce the maximum equivalent stress at the dangerous location. The maximum equivalent stress at this location is decreased by 15%. This paper provides some reference for the design of the gas turbine rotor.

Gas exchange between the forest and the atmosphere

International Nuclear Information System (INIS)

Murphy, C.E. Jr.

1985-01-01

Forest gas exchange is discussed in terms of the processes that control the rate of exchange with the atmosphere. Examples are presented to show how vegetative uptake control is varied for gases with different characteristics. The prediction of uptake for large areas and over long periods of time is discussed in terms of quantitative models of the gas exchange processes. Finally, remote sensing is suggested as a means of obtaining the parameters needed to make the model predictions. 46 refs., 6 figs

Neuronal death induced by misfolded prion protein is due to NAD+ depletion and can be relieved in vitro and in vivo by NAD+ replenishment

Science.gov (United States)

Zhou, Minghai; Ottenberg, Gregory; Sferrazza, Gian Franco; Hubbs, Christopher; Fallahi, Mohammad; Rumbaugh, Gavin; Brantley, Alicia F.

2015-01-01

The mechanisms of neuronal death in protein misfolding neurodegenerative diseases such as Alzheimer’s, Parkinson’s and prion diseases are poorly understood. We used a highly toxic misfolded prion protein (TPrP) model to understand neurotoxicity induced by prion protein misfolding. We show that abnormal autophagy activation and neuronal demise is due to severe, neuron-specific, nicotinamide adenine dinucleotide (NAD+) depletion. Toxic prion protein-exposed neuronal cells exhibit dramatic reductions of intracellular NAD+ followed by decreased ATP production, and are completely rescued by treatment with NAD+ or its precursor nicotinamide because of restoration of physiological NAD+ levels. Toxic prion protein-induced NAD+ depletion results from PARP1-independent excessive protein ADP-ribosylations. In vivo, toxic prion protein-induced degeneration of hippocampal neurons is prevented dose-dependently by intracerebral injection of NAD+. Intranasal NAD+ treatment of prion-infected sick mice significantly improves activity and delays motor impairment. Our study reveals NAD+ starvation as a novel mechanism of autophagy activation and neurodegeneration induced by a misfolded amyloidogenic protein. We propose the development of NAD+ replenishment strategies for neuroprotection in prion diseases and possibly other protein misfolding neurodegenerative diseases. PMID:25678560

Alternatives for the Santos Basin natural gas insertion in the energetic matrix; Alternativas para a insercao do gas da Bacia de Santos na matriz energetica. Estudo de caso: cidade de Santos

Energy Technology Data Exchange (ETDEWEB)

Awazu, Ricardo de Mello [Grupo MKR, Sao Paulo, SP (Brazil). Gerencia de Novos Negocios], e-mail: ricardo@mkr.com.br; Santos, Edmilson Moutinho dos [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Programa Interunidades de Pos-Graduacao em Energia (PIPGE)], e-mail: edsantos@iee.usp.br

2008-07-01

The natural gas difficult to penetrate in the residential market and compete with electrical energy is the main objective of this study, which will support that in big cities, where natural gas is already reality or will be the use of natural gas should not be considered competition for other types of energy resources but as a strategically complement of the overall power system. Electricity used as thermal source creates only demand for concessionaires and not consumption, in other words, there is short period of time when demand peaks and the amount of energy consumed by the electric shower is so high that requires a huge infra-structure of generation, transmission and distribution. However, it creates a big idle capacity in periods off-peak. The replacement of electricity to natural gas in water heating is critical factor to make the pipeline network economically feasible and to consolidate the residential market. The use of natural gas only to cooking purposes makes the network very costly and with high idle capacity. This study will discuss how an integrated planning of resources can lead to a better use of energy resources and distribution network of natural gas and electricity. (author)

Natural gas fuelling stations installation code

Energy Technology Data Exchange (ETDEWEB)

Barrigar, C; Burford, G; Adragna, M; Hawryn, S

2004-07-01

This Canadian Standard applies to natural gas fuelling stations that can be used for fleet and public dispensing operations. This document is divided into 11 sections that address the scope of the Standard; definitions and reference publications; general requirements; compressors; storage; dispensing; flow control devices; storage vessel dispatch and receiving; design, installation and testing of piping, tubing and fittings; and installation of vehicle refuelling appliances (VRAs) connected to storage piping. The most recent revision to the Standard includes requirements for indoor fuelling of natural gas vehicles. This Standard, like all Canadian Standards, was subject to periodic review and was most recently reaffirmed in 2004. tabs., figs.

Inventory control based on advanced probability theory, an application

CERN Document Server

Krever, Maarten; Schorr, Bernd; Wunderink, S

2005-01-01

Whenever stock is placed as a buffer between consumption and supply the decision when to replenish the stock is based on uncertain values of future demand and supply variables. Uncertainty exists about the replenishment lead time, about the number of demands and the quantities demanded during this period. We develop a new analytical expression for the reorder point, which is based on the desired service level and three distributions: the distribution of the quantity of single demands during lead time, the distribution of the lengths of time intervals between successive demands, and the distribution of the lead time itself. The distribution of lead time demand is derived from the distributions of individual demand quantities and not from the demand per period. It is not surprising that the resulting formulae for the mean and variance are different from those currently used. The theory developed is also applicable to periodic review systems. The system has been implemented at CERN and enables a significant enha...

Analysis of credit linked demand in an inventory model with varying ordering cost.

Science.gov (United States)

Banu, Ateka; Mondal, Shyamal Kumar

2016-01-01

In this paper, we have considered an economic order quantity model for deteriorating items with two-level trade credit policy in which a delay in payment is offered by a supplier to a retailer and also an another delay in payment is offered by the retailer to his/her all customers. Here, it is proposed that the demand function is dependent on the length of the customer's credit period and also the duration of offering the credit period. In this article, it is considered that the retailer's ordering cost per order depends on the number of replenishment cycles. The objective of this model is to establish a deterministic EOQ model of deteriorating items for the retailer to decide the position of customers credit period and the number of replenishment cycles in finite time horizon such that the retailer gets the maximum profit. Also, the model is explained with the help of some numerical examples.

Measurements of potato tubers gamma-ray irradiated in nitrogen gas or carbondioxide gas

International Nuclear Information System (INIS)

Katayama, Tadashi; Ohnishi, Tokuhiro; Dohmaru, Takaaki; Kanazawa, Tamotsu; Hiraoka, Eiichi; Furuta, Jun-ichiro.

1984-01-01

In this report the respiration of the potato tubers irradiated in nitrogen gas or carbondioxide gas was studied. Potato tubers of common Japanese variety, ''Danshaku'' were used for the examination. Potato tubers of about 2kg were put into each of Triple-Nylon bags and the bags were sealed after replacement of air in bags with nitrogen or carbondioxide gases. More than 16 hours after sealing of bags, the γ-dose ( 60 Co) of 150 Gy or 250 Gy were given to the potato tubers in bags at the dose rate of 10 4 R/h. After irradiation, all bags were opened in air and amounts of CO 2 released by respiration of tubers were measured with Hitachi gas chromatograph analyser Type 023. The amounts of CO 2 released from the potato tubers irradiated in open air is shown in Fig. 2. The results show that there is an initial lag period of several hours, followed by a rapid increase in the respiration, after which the CO 2 release was gradually decreased. Potato tubers irradiated in nitrogen gas show a similar release of CO 2 on time scale to the potato tubers irradiated in open air, but the total amounts of CO 2 are approximately half of those of the potato tubers irradiated in open air (Figs. 3 and 4). (J.P.N.)

Advanced dendritic web growth development and development of single-crystal silicon dendritic ribbon and high-efficiency solar cell program

Science.gov (United States)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.

1986-01-01

Efforts to demonstrate that the dendritic web technology is ready for commercial use by the end of 1986 continues. A commercial readiness goal involves improvements to crystal growth furnace throughput to demonstrate an area growth rate of greater than 15 sq cm/min while simultaneously growing 10 meters or more of ribbon under conditions of continuous melt replenishment. Continuous means that the silicon melt is being replenished at the same rate that it is being consumed by ribbon growth so that the melt level remains constant. Efforts continue on computer thermal modeling required to define high speed, low stress, continuous growth configurations; the study of convective effects in the molten silicon and growth furnace cover gas; on furnace component modifications; on web quality assessments; and on experimental growth activities.

Australia’s Consumption-based Greenhouse Gas Emissions

DEFF Research Database (Denmark)

Levitt, Clinton J.; Saaby, Morten; Sørensen, Anders

2017-01-01

We use data from the World Input-Output Database in a multiregional input–output model to analyse Australian consumption-based greenhouse gas emissions for the years 1995 to 2009. We find that the emission content of Australian macroeconomic activity has changed over the 15-year period. Consumption...

Coal and gas competition in global markets

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-07-01

Global consumption of commercial energy totalled 18 Gt of coal equivalent in 2010. With a 28% share, coal ranked second after oil as one of the major sources of primary energy and natural gas (at 21%) ranked third. Gross power generation with coal was approximately 41% and gas 22%. Natural gas as a global commodity is growing rapidly with the advent of unconventional sources such as shale gas. Recently, gas has become the fuel of choice for new power generating plants in some countries. Overall production of coal has increased in the same time-frame. The share of coal in electricity production was constant in Europe from early 2000 but recently increased. This was due to the high cost of gas in Europe and a low emissions penalty levied by the regulator, making coal currently more competitive in Europe compared to gas. Coal utilisation continues to increase in Asia but is facing serious competition with gas in the USA, where the share of electricity generated with coal dropped in 2012. However, natural gas used to generate electricity in early 2013 was below the high level seen during the comparable 2012 period, when low natural gas prices led to significant displacement of coal by natural gas for power generation. The current consensus in the USA is that while coal may recover ground in the short term, it loses in the long term as coal plants are retired. The discovery, production and availability of significant amounts of gas have implications for not only the price of natural gas but also the price of coal as well as supply and demand, and utilisation of both fuels internationally. The interaction between coal and gas in the global markets today is investigated in this review and the near-term outlook and impact on both fuels is presented. In this report, reserves, production and trade, supply and demand, pricing, utilisation and consumption, public attitudes and finally near/short to medium-term prospects are discussed for both coal and gas.

Russian Gas Market: Entering New Era

International Nuclear Information System (INIS)

Mitrova, Tatiana; Molnar, Gergely

2015-04-01

After a period of extensive growth in the 2000's, the Russian gas industry is now facing numerous challenges. Mounting competition by independent producers and the development of new production by Gazprom, combined with stagnating domestic demand and weakening export markets, have created a situation of overproduction, made worse by western sanctions and low oil and gas prices. Expansion to the East thanks to the recent China deal is not expected to provide much relief before 2024. The coming decade will be critical for the industry and its outcome will largely depend on the government's pricing and institutional policies but the role of the state should remain essential. This document presents the key findings of the New CEDIGAZ report 'Russian Gas Market: Entering New Era'. The report analyses the ongoing changes in the Russian industry and the challenges to be met

Recent Status RSG-GAS Ageing Management

Energy Technology Data Exchange (ETDEWEB)

Sunaryo, Geni Rina; Setianto; Tarigan, Alim [Puspiptek Area, Serpong (Indonesia); Wisnubroto, D. S. [Mampang Prapatan, Jakarta (Indonesia)

2013-07-01

RSG GAS Research Reactor.30 MW, which is the biggest scientific investment made by the Indonesian Government, is operating safely for about 27 years. This research reactor has been built and developed since year 1983. Critical attainment reached first on July 1987 and ceremonial opened by president of RI on August 20{sup th} 1987. Operated with full energy of 30 MW reached first time on March 1992. It started becoming commercially operated since 1995. RSG-GAS has a maximum thermal energy of 30 MW and has neutron flux of averaged 10{sup 14} n/cm{sup 2}.sec coming from fissile reaction. RSG-GAS is a reactor with pool type with fuel of 19.75% enriched U{sub 3}O{sub 8}Al/U{sub 3}Si{sub 2}Al and burned up ratio up to 56%. RSG GAS has been built for scientific purpose by utilizing neutron beam instruments and isotope productions. Facilities allowing Neutron Activation Analysis for research and industry are both on-line. For affording the utilization or the reactor operation approaching the designed life, the progressive ageing management is being applied. This paper will address the ageing management based on the importance to safety and SSC replacement ease consideration, which is implemented on RSG GAS. It consist of minimization of expected ageing prevention which is divided into prevention actions and followed by periodic review of this effectiveness, detection, monitoring and trending of ageing degradation through periodically inspections, and testing. Some activities such as NDT-ultrasonic to mitigating the ageing degradation of secondary water pipe lines, underwater camera for tank liners, infrared thermograph for understanding the cable insulation age, Eddy Current for inspecting the Heat Exchangers, surveillance corrosion for understanding the corrosion mechanism and structure material lifetime by immersing cupons into primary, secondary and raw water basin for many years and some ended by refurbishment-for secondary pump, are being applied. Based on the results

Theoretical innovation and technical progress will usher in a production period of gas fields with an annual capacity of ten billion cubic meters

Directory of Open Access Journals (Sweden)

Zhenwei Gan

2017-01-01

Full Text Available Challenged by the increasing complexity of targets and the tense situation of turning losses into profits during the 12th Five-Year Plan, by virtue of technological innovation, Sinopec Southwest Oil & Gas Company proposed the theories of gas exploration in continental clastic rock and marine carbonate rock, and developed the development technologies for reef, channel sandstone and tight sandstone reservoirs. Moreover, it innovatively formed a series of engineering technologies, including intelligent sliding sleeve staged fracturing, blasting–packing–fracturing stimulation, impulse fracturing, and drilling, completion and production technologies for ultra-deep horizontal wells with high sulfur contents. With these innovated theories and improved technologies, great discoveries have been made in the continental clastic rocks and marine carbonate rocks in West Sichuan Basin, the marine shale in South Sichuan Basin, and the marine carbonate rocks in Yuanba area of NE Sichuan Basin, and three 100 billion-m3 class commercial gas reserves zones were discovered. Moreover, two medium- and large-sized gas fields were proved, and three medium- and large-sized gas fields were completely constructed. Both reserves and production reached a new record in history. During the 13th Five-Year Plan, Sinopec Southwest Oil & Gas Company will focus on the exploration and development of deep marine carbonate reservoirs, commercial development of deep shale gas, safe development of gas fields with high sulfur, and enhancement of recovery in mature gas fields. By the end of the 13th Five-Year Plan, it is expected that the annual gas production of (10–12 × 109 m3 will be achieved.

Desulfurization kinetics of molten copper by gas bubbling

Science.gov (United States)

Fukunaka, Y.; Nishikawa, K.; Sohn, H. S.; Asaki, Z.

1991-02-01

Molten copper with 0.74 wt pct sulfur content was desulfurized at 1523 K by bubbling Ar-O2 gas through a submerged nozzle. The reaction rate was significantly influenced not only by the oxygen partial pressure but also by the gas flow rate. Little evolution of SO2 gas was observed in the initial 10 seconds of the oxidation; however, this was followed by a period of high evolution rate of SO2 gas. The partial pressure of SO2 gas decreased with further progress of the desulfurization. The effect of the immersion depth of the submerged nozzle was negligible. The overall reaction is decomposed to two elementary reactions: the desulfurization and the dissolution rate of oxygen. The assumptions were made that these reactions are at equilibrium and that the reaction rates are controlled by mass transfer rates within and around the gas bubble. The time variations of sulfur and oxygen contents in the melt and the SO2 partial pressure in the off-gas under various bubbling conditions were well explained by the mathematical model combined with the reported thermodynamic data of these reactions. Based on the present model, it was anticipated that the oxidation rate around a single gas bubble was mainly determined by the rate of gas-phase mass transfer, but all oxygen gas blown into the melt was virtually consumed to the desulfurization and dissolution reactions before it escaped from the melt surface.

A small capacity co generative gas-turbine plant in factory AD 'Komuna' - Skopje (Macedonia)

International Nuclear Information System (INIS)

Dimitrov, Konstantin; Armenski, Slave; Tashevski, Done

2000-01-01

The factory AD 'Komuna' -Skopje (Macedonia), has two steam block boilers, type ST 800 for steam production for process and space heating. The factory satisfies the electricity needs from the national grid. By the use of natural gas like fuel it is possible to produce electrical energy in its own co generative gas turbine plant. In this article, a co generative plant with small-scale gas turbine for electricity production is analyzed . The gas from gas turbine have been introduce in the steam block boiler. Also, a natural gas consumption, the electricity production, total investment and payback period of investment are determined. (Authors)

Gas and Gas Pains

Science.gov (United States)

... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

World crude oil and natural gas. A demand and supply model

International Nuclear Information System (INIS)

Krichene, Noureddine

2002-01-01

This paper examines world markets for crude oil and natural gas over the period 1918-1999; it analyzes the time-series properties of output and prices and estimates demand and supply elasticities during 1918-1973 and 1973-1999. Oil and gas prices were stable during the first period; they became volatile afterwards, reflecting deep changes in the market structure following the oil shock in 1973. Demand price elasticities were too low; however, demand income elasticities were high. Supply price elasticities were also too low. The elasticity estimates help to explain the market power of the oil producers and price volatility in response to shocks, and corroborate elasticity estimates in energy studies

Gas, gas, gas... discoveries and developments booming worldwide

International Nuclear Information System (INIS)

Maxwell, F.

2000-01-01

Deep water exploration is yielding more than billion barrel oil fields. Unocal's 3 May discovery of 2-3 Tcf of gas in its Kutei block of Indonesia marks the first major discovery of natural gas in the deep water frontier: Wildcats Gula and Gada were drilled in over 1800 m of water as part of an aggressive search for gas instigated by Unocal last year. The author makes a survey of gas exploration and development throughout the world. (author)

Requirements for gas quality and gas appliances

NARCIS (Netherlands)

Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

2015-01-01

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

Upstream oil and gas. Subsector no. 7: Oil and gas exploration and development 1995 to 1999

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-08-01

Prepared by the Alberta Human Resources and Employment, this report provides a summary of the lost-time injuries and disease descriptions of workers injured while employed in the upstream oil and gas industries in Alberta during the period 1995 to 1999. The report includes the characteristics of the injured worker and the risk of injury to workers in the industries in Alberta, as well as the cost of injuries and revenue by means of total premiums paid by the employers. The occupational fatalities that were accepted by the Workers Compensation Board and investigated by the Occupational Health and Safety were summarized in the report along with a brief description of the injuries. The aim was to provide information concerning health and safety issues to government, employers, workers, and health and safety officers in the industries in Alberta about health and safety issues. The focus was placed on the oil and gas exploration and development sub-sector. Defined as all upstream oil field activities of employers which generate revenue from the production and sale of crude oil and/or natural gas, the sub-sector comprises major integrated oil and gas companies and small independent producers. In those cases where the owner/producer operates its own upstream production/processing facilities, they form an integral part of this sub-section. In addition, oil and gas marketing firms are included. Oil/gas well, well head equipment; flow lines/gathering systems tied into field processing facilities; battery sites/compressors stations; crude oil separators and natural gas dehydrators/treaters; natural gas/sulfur processing plants; heavy oil projects including steam generation; and other enhanced recovery methods are all included in the sub-sector. The other sub-sectors in the upstream oil and gas industries are: exploration, oilfield maintenance and construction, well servicing with service rigs and power swivels, drilling of oil and gas wells, oilfield downhole and other

On the infimum of the energy-momentum spectrum of a homogeneous Bose gas

DEFF Research Database (Denmark)

Cornean, Horia; Derezinski, J.; Zin, P.

2009-01-01

We consider second-quantized homogeneous Bose gas in a large cubic box with periodic boundary conditions at zero temperature. We discuss the energy-momentum spectrum of the Bose gas and its physical significance. We review various rigorous and heuristic results as well as open conjectures about its...

Natural gas production from underground nuclear explosions

Energy Technology Data Exchange (ETDEWEB)

1965-01-01

A remote location in Rio Arriba County, NW. New Mexico, is being considered as the site for an experiment in the use of a nuclear explosive to increase production from a natural gas field. A feasibility study has been conducted by the El Paso Natural Gas Co., the U.S. Atomic Energy commission, and the U.S. Bureau of Mines. As presently conceived, a nuclear explosive would be set in an emplacement hole and detonated. The explosion would create a cylinder or ''chimney'' of collapsed rock, and a network of fractures extending beyond the chimney. The fractures are the key effect. These would consist of new fractures, enlargement of existing ones, and movement along planes where strata overlap. In addition, there are a number of intangible but important benefits that could accrue from the stimulating effect. Among these are the great increase in recoverable reserves and the deliverability of large volumes of gas during the periods of high demand. It is believed that this type of well stimulation may increase the total gas production of these low permeability natural gas fields by about 7 times the amounts now attainable.

The mechanics of green power : emission benefits and credits in voluntary and commitment periods

International Nuclear Information System (INIS)

Hyndman, R.

1998-01-01

The challenge facing the electric power industry in reducing greenhouse gas emissions under the Kyoto Protocol was discussed. The paper illustrates the emission reduction incentives prior to and during the commitment period, with particular focus on pricing. It was noted that in the absence of greenhouse gas emission reduction incentives and prices, coal has a lower running cost and would be dispatched ahead of oil and natural gas. The same situation exists with respect to nuclear, hydro and wind, all of which have lower marginal running costs than fossil fuel plants, thus will run ahead of fossil fuel plants wherever they are available. Various models of the electricity market in North America were demonstrated. The issue of how to determine the amount of greenhouse gas offset and its significance was also addressed. figs

Temperature-dependent evolution of chemisorbed digermane in Ge thin film growth

International Nuclear Information System (INIS)

Eres, D.; Sharp, J.W.

1992-01-01

The formation and evolution of chemisorbed digermane layers in context with germanium thin film growth was investigated by time- resolved surface reflectometry. Modulation of the source gas supply made possible the separation and independent study of the temperature dependence of the adsorption and desorption processes. The regeneration of active sites by molecular hydrogen desorption was identified as the rate-limiting step at low substrate temperatures. A dynamic method of thin film growth was demonstrated by repetitively replenishing the active film growth sites regenerated between two successive source gas pulses. The film growth rate was shown to be related to the substrate temperature and the delay time between successive source gas pulses

Prospective of the Natural Gas marketing 2002-2011

International Nuclear Information System (INIS)

2002-01-01

According with the 109 Th Article of the Natural Gas Regulations the Secretaria de Energia publishes this prospective of the Natural gas market 2002-2011 which describes and analyses the necessities of Mexico in relation with this industry in the mentioned period. Here aspects such as: the present and future international panorama of the natural gas market, international prices, the world demand with base in the Department of Energy (DOE) turnover of the United States, Advances of the in force regulatory framework, Sales, the National Gas pipeline system, Evolution of the National market, Demand at regional and sectoral scales, Supply analysis, Programs and projects of energy savings, natural gas balance with the high demand scene, the methodology of the Instituto Mexicano del Petroleo for calculating the self-generation demand of the electric energy by sector, a glossary with the more used terms, conversion factors and abbreviations and acronyms used in the document are treated. In the next ten years, the national demand of natural gas will suffer an annual average growth of 7.4% passing from 4358 millions of daily cubic feet (mm pcd) in 2001 to 8883 mm pcd in 2011. (Author)

Measurement of Clathrate Hydrate Thermodynamic Stability in the Presence of Ammonia

Science.gov (United States)

Dunham, Marc

2012-01-01

There is a lack of data available for the stability of clathrate hydrates in the presence of ammonia for low-to-moderate pressures in the 0-10 MPa range. Providing such data will allow for a better understanding of natural mass transfer processes on celestial bodies like Titan and Enceladus, on which destabilization of clathrates may be responsible for replenishment of gases in the atmosphere. The experimental process utilizes a custom-built gas handling system (GHS) and a cryogenic calorimeter to allow for the efficient testing of samples under varying pressures and gas species.

Pricing natural gas distribution in Mexico

International Nuclear Information System (INIS)

Ramirez, Jose Carlos; Rosellon, Juan

2002-01-01

We examine regulation of distribution tariffs in the Mexican natural gas industry. Average revenue in each period is constrained not to exceed an upper bound and is calculated as the ratio of total revenue to output in the current period. This regime implies incentives for strategically setting two-part tariffs. The usage charge is typically dropped to its lowest feasible level, while the fixed charge is raised to compensate for the loss of profit. The regime also creates a stochastic effect that implies decreased values of consumer surplus for lower levels of risk aversion and uncertainty

Price dynamics of natural gas and the regional methanol markets

International Nuclear Information System (INIS)

Masih, A. Mansur M.; Albinali, Khaled; DeMello, Lurion

2010-01-01

A 'methanol economy' based mainly on natural gas as a feedstock has a lot of potential to cope with the current and ongoing concerns for energy security along with the reduction of CO-2 emissions. It is, therefore, important to examine the price dynamics of methanol in order to ascertain whether the price of methanol is mainly natural-gas-cost driven or demand driven in the context of different regions. This paper is the first attempt to investigate the following: (1) is the natural gas price significantly related to the regional methanol prices in the Far East, United States and Europe? (2) who drives the regional methanol prices? The paper is motivated by the recent and growing debate on the lead-lag relationship between natural gas and methanol prices. Our findings, based on the most recently developed 'long-run structural modelling' and subject to the limitations of the study, tend to suggest: (1) natural gas price is cointegrated with the regional methanol prices, (2) our within-sample error-correction model results tend to indicate that natural gas was driving the methanol prices in Europe and the United States but not in the Far East. These results are consistent, during most of the period under review (1998.5-2007.3), with the surge in demand for methanol throughout the Far East, particularly in China, Taiwan and South Korea, which appears to have played a relatively more dominant role in the Far East compared to that in Europe and the United States within the framework of the dynamic interactions of input and product prices. However, during the post-sample forecast period as evidenced in our variance decompositions analysis, the emergence of natural gas as the main driver of methanol prices in all three continents is consistent with the recent surge in natural gas price fueled mainly, among others, by the strong hedging activities in the natural gas futures/options as well as refining tightness (similar to those that were happening in the crude oil markets

Asphalt features and gas accumulation mechanism of Sinian reservoirs in the Tongwan Palaeo-uplift, Sichuan Basin

Directory of Open Access Journals (Sweden)

Wei Li

2015-10-01

Full Text Available Breakthroughs have been made in natural gas exploration in Sinian reservoirs in the Tongwan Palaeo-uplift, Sichuan Basin, recently. However, there are disputes with regard to the genetic mechanisms of natural gas reservoirs. The development law of asphalts in the Sinian reservoirs may play an extremely important role in the study of the relationships between palaeo oil and gas reservoirs. Accordingly, researches were conducted on the features and development patterns of asphalts in the Sinian reservoirs in this area. The following research results were obtained. (1 Asphalts in the Sinian reservoirs were developed after the important hydrothermal event in the Sichuan Basin, namely the well-known Emei Taphrogeny in the mid-late Permian Period. (2 Distribution of asphalts is related to palaeo oil reservoirs under the control of palaeo-structures of Indosinian-Yanshanian Period, when the palaeo-structures contained high content of asphalts in the high positions of the palaeo-uplift. (3 Large-scale oil and gas accumulations in the Sinian reservoirs occurred in the Indosinian-Yanshanian Period to generate the Leshan-Ziyang and Gaoshiti-Moxi-Guang'an palaeo oil reservoirs. Cracking of crude oil in the major parts of these palaeo oil reservoirs controlled the development of the present natural gas reservoirs. (4 The development of asphalts in the Sinian reservoirs indicates that hydrocarbons in the Dengying Formation originated from Cambrian source rocks and natural gas accumulated in the Sinian reservoirs are products of late-stage cracking of the Sinian reservoirs. (5 The Sinian palaeo-structures of Indosinian-Yanshanian Period in the Sichuan Basin are favorable regions for the development of the Sinian reservoirs, where discoveries and exploration practices will play an important role in the era of Sinian natural gas development in China.

Greenhouse gas quotas on the Norwegian continental shelf

International Nuclear Information System (INIS)

Torvanger, Asbjoern; Godal, Odd; Kolshus, Hans H.; Aaheim, Asbjoern

2002-01-01

This report discusses advantages and disadvantages of voluntary quota obligations in a greenhouse gas emissions trading system at the company level, and advantages and disadvantages associated with various initial allocation mechanisms in a quota system. The analysis is based on the situation for the Norwegian oil industry in an early Norwegian emissions trading system in the period 2005-2007, and on oil companies' participation in international emissions trading under the Kyoto Protocol in the period 2008-2012. The report has been commissioned by the Norwegian Oil Industry Association, and was written in the period March-April 2002. (author)

U.S. gas outlook: A better year ahead

International Nuclear Information System (INIS)

Parent, L.

1996-01-01

Considering the mixed bag of factors affecting the US gas industry--restructuring, better prices, hopefully better margins, higher production, better drilling in some locations and some iffy stuff in the regulatory scene--the overall analysis is for a generally better year. After an extended period of low prices, the recent price surge is a welcome change. While the price roller coaster will probably continue, there should be, on the average, a $0.15--0.20 per Mcf improvement over 1995. Gas prices and the futures market are discussed further in the paper. Other conclusions developed in this article to support a basically optimistic outlook overview include: supply/demand; gas well drilling; entrance of electric power; integrated seamless pipeline networks; capacity turnback; and Canada/Mexico factors

Numerical analysis of pressure and porosity evolution in lava domes during periodic degassing conditions

Science.gov (United States)

Hyman, D.; Bursik, M. I.; Pitman, E. B.

2017-12-01

The collapse or explosive breakup of growing and degassing lava domes presents a significant hazard due to the generation of dense, mobile pyroclastic flows as well as the wide dispersal of dense ballistic blocks. Lava dome stability is in large part governed by the balance of transport and storage of gas within the pore space. Because pore pressurization reduces the effective stress within a dome, the transient distribution of elevated gas pressure is critically important to understanding dome break up. We combine mathematical and numerical analyses to gain a better understanding of the temporal variation in gas flow and storage within the dome system. In doing so, we develop and analyze new governing equations describing nonlinear gas pressure diffusion in a deforming dome with an evolving porosity field. By relating porosity, permeability, and pressure, we show that the flux of gas through a dome is highly sensitive to the porosity distribution and viscosity of the lava, as well as the timescale and magnitude of the gas supply. The numerical results suggest that the diffusion of pressure and porosity variations play an integral role in the cyclic growth and destruction of small domes.The nearly continuous cycles of lava dome growth, pressurization, and failure that have characterized the last two decades of eruptive history at Volcán Popocatépetl, Mexico provide excellent natural data with which to compare new models of transient dome pressurization. At Popocatépetl, periodic pressure increases brought on by changes in gas supply into the base of the dome may play a role in its cyclic growth and destruction behavior. We compare our model of cyclic pressurization with lava dome survival data from Popocatépetl. We show that transient changes in pore pressure explain how small lava domes evolve to a state of criticality before explosion or collapse. Additionally, numerical analyses presented here suggest that short-term oscillations cannot arise within the dome

Natural gas conversion program of Rio de Janeiro-Brazil; Projeto de conversao do sistema de distribuicao de gas canalizado na cidade do Rio de Janeiro

Energy Technology Data Exchange (ETDEWEB)

Pallottino, J.T.; Costa Filho, M.A.F.; Guarana, L.F.M.L. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Margalef, J.M. [Companhia Estadual de Gas (CEG), Rio de Janeiro, RJ (Brazil)

2008-07-01

This paper presents the Conversion Project of Rio de Janeiro, Brazil, that converted all customers and the distribution network from Manufactured Gas (MG) to Natural Gas (NG), evaluating its logistic and benefits, highlighting those related to consumer safety. The Conversion Project was executed under the responsibility of CEG with the support of UERJ, specially on the definition and revision of the technical procedures as well as the quality assurance of the project execution. As main advantages followed by MG to NG network conversion, we can note: increasing of gas distribution network capacity and gas network operational condition improvements; elimination of production plant; revision and renovation of gas network; revision and repairing of building gas facilities; augmenting of NG usage; elimination of carbon monoxide as a supplied gas constituent. Conservation condition of most consumer internal gas facilities and ambient ventilation were so critical that conversion program resulted in no measurable accident prevention. The achieved safety level should be maintained through a periodically re-evaluation program of customer's gas facilities and appliances, with special focus on permanent ventilation required for NG safety usage. (author)

A comparison of the structure and organisation of the West German and the U. S. gas industries. Consequences for the status of gas utility companies

Energy Technology Data Exchange (ETDEWEB)

Dirrheimer, M J; Teece, D J

1989-03-01

When comparing the West German gas industry to the United States one finds some striking differences in their structure and organisation. The German industry is small but growing, vertically integrated, efficient and scarcely regulated. The US-industry is big, hardly integrated and just recovering from years of frictions caused by successive waves of misguided regulations which were interrupted only by short periods of deregulation. Violation of contracts, price rises, price dumps, 'evasions', law suits are characteristic of today's American gas industry. The history of regulations in the U.S. gas industry is a nightmare other countries have fortunately been able to avoid. (orig.).

Long-term autonomous volcanic gas monitoring with Multi-GAS at Mount St. Helens, Washington, and Augustine Volcano, Alaska

Science.gov (United States)

Kelly, P. J.; Ketner, D. M.; Kern, C.; Lahusen, R. G.; Lockett, C.; Parker, T.; Paskievitch, J.; Pauk, B.; Rinehart, A.; Werner, C. A.

2015-12-01

In recent years, the USGS Volcano Hazards Program has worked to implement continuous real-time in situ volcanic gas monitoring at volcanoes in the Cascade Range and Alaska. The main goal of this ongoing effort is to better link the compositions of volcanic gases to other real-time monitoring data, such as seismicity and deformation, in order to improve baseline monitoring and early detection of volcanic unrest. Due to the remote and difficult-to-access nature of volcanic-gas monitoring sites in the Cascades and Alaska, we developed Multi-GAS instruments that can operate unattended for long periods of time with minimal direct maintenance from field personnel. Our Multi-GAS stations measure H2O, CO2, SO2, and H2S gas concentrations, are comprised entirely of commercial off-the-shelf components, and are powered by small solar energy systems. One notable feature of our Multi-GAS stations is that they include a unique capability to perform automated CO2, SO2, and H2S sensor verifications using portable gas standards while deployed in the field, thereby allowing for rigorous tracking of sensor performances. In addition, we have developed novel onboard data-processing routines that allow diagnostic and monitoring data - including gas ratios (e.g. CO2/SO2) - to be streamed in real time to internal observatory and public web pages without user input. Here we present over one year of continuous data from a permanent Multi-GAS station installed in August 2014 in the crater of Mount St. Helens, Washington, and several months of data from a station installed near the summit of Augustine Volcano, Alaska in June 2015. Data from the Mount St. Helens Multi-GAS station has been streaming to a public USGS site since early 2015, a first for a permanent Multi-GAS site. Neither station has detected significant changes in gas concentrations or compositions since they were installed, consistent with low levels of seismicity and deformation.

Assessment of demand for natural gas from the electricity sector in India

DEFF Research Database (Denmark)

Shukla, P.R.; Dhar, Subash; Victor, David G.

2009-01-01

Electricity sector is among the key users of natural gas. The sustained electricity deficit and environment policies have added to an already rising demand for gas. This paper tries to understand gas demand in future from electricity sector. This paper models the future demand for gas in India from...... the electricity sector under alternative scenarios for the period 2005–2025, using bottom-up ANSWER MARKAL model. The scenarios are differentiated by alternate economic growth projections and policies related to coal reforms, infrastructure choices and local environment. The results across scenarios show that gas...... competes with coal as a base-load option if price difference is below US $ 4 per MBtu. At higher price difference gas penetrates only the peak power market. Gas demand is lower in the high economic growth scenario, since electricity sector is more flexible in substitution of primary energy. Gas demand...

Alterations in plants through action of nitrous gas

Energy Technology Data Exchange (ETDEWEB)

Cristiani, H

1927-01-01

Leaves of plants were exposed to atmospheres containing nitrous gases typical of industrial pollution for periods ranging from 15 minutes to 18 hours. The leaves were washed after drying and concentrations of nitrates and nitrites in the leachate/wash water were determined. Accumulation of nitrites seems to be minor, but the nitrate concentration in the leaves was high, even though the leaves were exposed to an atmosphere poor in nitrous gas for periods of 9-18 hours.

Improving the performances of gas turbines operated on natural gas in combined cycle power plants with application of mathematical models

International Nuclear Information System (INIS)

Dimkovski, Sasho

2014-01-01

The greater energy demand by today society sets a number of new challenges in the energy sector. The climate extremes impose new modes of operation of the power plants, with high flexibility in production. Combined cycle co generative power plants are the latest trend in the energy sector. Their high prevalence is due to the great efficiency and the good environmental characteristics. The main work horse in these cogeneration plants is the gas turbine, which power production and efficiency strongly depends on the external climate conditions. In warmer periods when there is increased demand for electricity, the power production from the gas turbines significantly declines. Because of the high electricity demand from the grid and reduced power production from the gas turbines at the same time, the need for application of appropriate technology for preserving the performances and power of the gas turbines arises. This master thesis explores different methods to improve the power in gas turbines by cooling the air on the compressor inlet, analyzing their applicability and effectiveness in order to choose the optimal method for power augmentation for the climatic conditions in the city Skopje. The master thesis gives detailed analysis of the weather in Skopje and the time frame in which the chosen method is applicable. At the end in the master thesis, the economic feasibility of the given method for power augmentation is clearly calculated, using a model of a power plant and calculating the resulting amount of gained energy, the amount of the initial investment, the cost for maintenance and operation of the equipment. By these calculations the period for initial return of investment is obtained. As an added benefit the positive environmental impacts of the applied technology for inlet air cooling is analyzed. (author)

Field intercomparison of four methane gas analyzers suitable for eddy covariance flux measurements

Science.gov (United States)

Peltola, O.; Mammarella, I.; Haapanala, S.; Burba, G.; Vesala, T.

2013-06-01

Performances of four methane gas analyzers suitable for eddy covariance measurements are assessed. The assessment and comparison was performed by analyzing eddy covariance data obtained during summer 2010 (1 April to 26 October) at a pristine fen, Siikaneva, Southern Finland. High methane fluxes with pronounced seasonality have been measured at this fen. The four participating methane gas analyzers are commercially available closed-path units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research, USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit Prototype-7700 (LI-COR Biosciences, USA). The RMT-200 functioned most reliably throughout the measurement campaign, during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had the smallest random errors and the fluxes agree remarkably well throughout the measurement campaign. Cospectra and power spectra calculated from RMT-200 and G1301-f data agree well with corresponding temperature spectra during a high flux period. None of the gas analyzers showed statistically significant diurnal variation for methane flux. Prototype-7700 functioned only for a short period of time, over one month, in the beginning of the measurement campaign during low flux period, and thus, its overall accuracy and season-long performance were not assessed. The open-path gas analyzer is a practical choice for measurement sites in remote locations due to its low power demand, whereas for G1301-f methane measurements interference from water vapor is straightforward to correct since the instrument measures both gases simultaneously. In any case, if only the performance in this intercomparison is considered, RMT-200 performed the best and is the recommended choice if a new fast response methane gas analyzer is needed.

A comparative study of gas-gas miscibility processes in underground gas storage reservoirs

Energy Technology Data Exchange (ETDEWEB)

Rafiee, M.M.; Schmitz, S. [DBI - Gastechnologisches Institut gGmbH, Freiberg (Germany)

2013-08-01

Intermixture of gases in underground gas reservoirs have had great weight for natural gas storage in UGS projects with substitution of cushion gas by inert gases or changing the stored gas quality or origin, as for the replacement of town gas by natural gas. It was also investigated during the last years for Enhanced Gas Recovery (EGR) and Carbon Capture and Storage (CCS) projects. The actual importance of its mechanisms is discussed for the H{sub 2} storage in Power to Gas to Power projects (PGP). In these approaches miscibility of the injected gas with the gas in place in the reservoir plays an important role in the displacement process. The conditions and parameters for the gas-gas displacement and mixing have been investigated in previous projects, as e.g. the miscibility of CO{sub 2} with natural gas (CLEAN). Furthermore the miscibility process of town gas with natural gas and sauer gas with sweet gas were also previously measured and compared in laboratory. The objective of this work is to investigate the miscibility of H{sub 2} injection into natural gas reservoirs using a compositional and a black oil reservoir simulator. Three processes of convection, dispersion and diffusion are considered precisely. The effect of gas miscibility is studied for both simulators and the results are compared to find optimum miscibility parameters. The findings of this work could be helpful for further pilot and field case studies to predict and monitor the changes in gas composition and quality. In future this monitoring might become more important when PGP together with H{sub 2}-UGS, as storage technology, will help to successfully implement the change to an energy supply from more renewable sources. Similarly the method confirms the use of the black oil simulator as an alternative for gas-gas displacement and sequestration reservoir simulation in comparison to the compositional simulator. (orig.)

Catalytic performance improvement of styrene hydrogenation in trickle bed reactor by using periodic operation

International Nuclear Information System (INIS)

Wongkia, Atittahn; Praserthdam, Piyasan; Assabumrungrat, Suttichai; Suriye, Kongkiat; Nonkhamwong, Anuwat

2013-01-01

We investigated the catalytic performance improvement of styrene hydrogenation in a trickle bed reactor by using periodic operation. The effects of cycle period and split on relative conversion, which is defined as styrene conversion obtained from periodic operation over that from steady state operation, were examined at various operating conditions including gas and average liquid flow rates, pressure and temperature. The experimental results reveal that both cycle period and split have strong influence on the catalytic performance. The fast mode (short cycle period) is a favorable condition. The improvement by the periodic operation becomes less pronounced for operations at high average liquid flow rate, pressure and temperature. From this study, a maximum improvement of styrene conversion of 18% is observed

Catalytic performance improvement of styrene hydrogenation in trickle bed reactor by using periodic operation

Energy Technology Data Exchange (ETDEWEB)

Wongkia, Atittahn; Praserthdam, Piyasan; Assabumrungrat, Suttichai [Chulalongkorn University, Bangkok (Thailand); Suriye, Kongkiat; Nonkhamwong, Anuwat [SCG Chemicals Co. Ltd., Bangkok (Thailand)

2013-03-15

We investigated the catalytic performance improvement of styrene hydrogenation in a trickle bed reactor by using periodic operation. The effects of cycle period and split on relative conversion, which is defined as styrene conversion obtained from periodic operation over that from steady state operation, were examined at various operating conditions including gas and average liquid flow rates, pressure and temperature. The experimental results reveal that both cycle period and split have strong influence on the catalytic performance. The fast mode (short cycle period) is a favorable condition. The improvement by the periodic operation becomes less pronounced for operations at high average liquid flow rate, pressure and temperature. From this study, a maximum improvement of styrene conversion of 18% is observed.

Activities of the Oil Implementation Task Force, reporting period March--August 1991; Contracts for field projects and supporting research on enhanced oil recovery, reporting period October--December 1990

Energy Technology Data Exchange (ETDEWEB)

1991-10-01

Activities of DOE's Oil Implementation Task Force for the period March--August 1991 are reviewed. Contracts for fields projects and supporting research on enhanced oil recovery are discussed, with a list of related publications given. Enhanced recovery processes covered include chemical flooding, gas displacement, thermal recovery, and microbial recovery.

British Gas plans global gas unit expansion

International Nuclear Information System (INIS)

Vielvoye, R.

1991-01-01

This paper reports on developing a global gas business, a British Gas plc's strategy for evolving a state owned U.K. gas company to a privatized worldwide oil and gas giant. By 2000, BG's global gas business is expected to provide 20% of its revenues, compared with 40% each from its exploration and production operations and its U.K. gas business. The global gas unit (GGU) plans to meet its targets mainly through acquiring holdings in gas transmission and distribution companies around the world. In the 12 months since GGU was established, it has made two such major acquisitions in this area. BG acquired Consumers Gas Co., Ltd., Ontario, Canada's biggest natural gas distribution company, for $943.5 million. It also took a 10% stake in Catalana de Gas SA, Barcelona, the largest privately owned gas utility in Spain and in terms of number of customers, the fourth largest in western Europe. BG also is targeting additional revenues from developing gas fired cogeneration systems in developing countries with gas reserves but no established transmission and distribution systems

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Tin dioxide opals and inverted opals: near-ideal microstructures for gas sensors

Energy Technology Data Exchange (ETDEWEB)

Scott, R.W.J.; Yang, S.M.; Coombs, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Materials Chemistry Research Group; Chabanis, G.; Williams, D.E. [University Coll., London (United Kingdom). Dept. of Chemistry

2001-10-02

Periodic macroporous forms of nc-SnO{sub 2} have been synthesized by two methods, giving opals and inverse opals that can be used as structurally well-defined gas sensors, as demonstrated for CO gas, as well as for toluene and ethanol vapors. The inverse opals, in particular, seem to approximate ''ideal'' behavior. (orig.)

Research for rolling effects on flow pattern of gas-water flow in horizontal tubes

International Nuclear Information System (INIS)

Luan Feng; Yan Changqi

2007-01-01

The flow pattern transition of two-phase flow is caused by the inertial force resulted from rolling and incline of horizontal tubes under rolling state. an experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state, which rolling period is 15 second and rolling angle is 10 degrees, and a pattern flow picture is shown. It was found that there are two flow patterns in one rolling period under some gas flux and water flux. (authors)

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

Science.gov (United States)

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

2017-04-01

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

Gas-export potential will grow until domestic economies hike local demand

International Nuclear Information System (INIS)

Carson, M.; Stram, B.

1993-01-01

Prospects appear good for near-term growth of exportable natural-gas supplies for some member countries of the Commonwealth of Independent States (C.I.S.). These conclusions are a result of Enron Corp.'s recent investigations in the C.I.S. and other former Soviet republics. They are based on data obtained in cooperation with Vinigaz, the research arm of the Russian state gas concern Gazprom, and from various other research and consulting groups. These studies indicate that gas-export potential will grow as local demand for gas shrinks in the C.I.S. (as the energy needs of the individual republics decline during the period of economic transition) and while the C.I.S.-area countries continue to require foreign currency to help fund redevelopment and reduce debt. This concluding of two articles reviews the economic outlook for outside investment in the oil, gas, and gas-liquids infrastructure and the role of natural-gas supply and price in the development of domestic and export markets