Chronic Conditions PUF

Data.gov (United States)

U.S. Department of Health & Human Services — The Chronic Conditions PUFs are aggregated files in which each record is a profile or cell defined by the characteristics of Medicare beneficiaries. A profile is...

Plasma confinement modification and convective transport suppression in the scrape-off layer using additional gas puffing in the STOR-M tokamak

International Nuclear Information System (INIS)

Dreval, M; Hubeny, M; Ding, Y; Onchi, T; Liu, Y; Hthu, K; Elgriw, S; Xiao, C; Hirose, A

2013-01-01

The influence of short gas puffing (GP) pulses on the scrape-off layer (SOL) transport is studied. Similar responses of ion saturation current and floating potential measured near the GP injection valve and in the 90° toroidally separated cross-section suggest that the GP influence on the SOL region should be global. A drop in plasma temperature and a decrease in the rotational velocity of the plasma are observed in the SOL region immediately after the GP pulse; however, an unexpected increase in electron and ion temperatures is observed in the second stage of the plasma response. The decrease in floating potential fluctuations indicates that the turbulent transport is dumped immediately after the GP pulse. The GP-induced modification of turbulence properties in the SOL points to a convective transport suppression in the STOR-M tokamak. A substantial decrease in the skewness and kurtosis of ion saturation current fluctuations is observed in the SOL region resulting in the probability distribution function (PDF) getting closer to the Gaussian distribution. The plasma potential reduction, the change in plasma rotation and the suppression of turbulent transport in the SOL region indicate that the plasma confinement is modified after the GP injection. Some features of the H-mode-like confinement in the plasma bulk also accompany the SOL observations after application of the additional sharp GP pulse. (paper)

Detecting Recycled Commodity SoCs: Exploiting Aging-Induced SRAM PUF Unreliability

OpenAIRE

Gao, Yansong; Ma, Hua; Al-Sarawi, Said F.; Abbott, Derek; Ranasinghe, Damith C.

2017-01-01

A physical unclonable function (PUF), analogous to a human fingerprint, has gained an enormous amount of attention from both academia and industry. SRAM PUF is among one of the popular silicon PUF constructions that exploits random initial power-up states from SRAM cells to extract hardware intrinsic secrets for identification and key generation applications. The advantage of SRAM PUFs is that they are widely embedded into commodity devices, thus such a PUF is obtained without a custom design...

Authenticated communication from quantum readout of PUFs

NARCIS (Netherlands)

Skoric, Boris; Pinkse, Pepijn Willemszoon Harry; Mosk, Allard

2016-01-01

Quantum Readout of Physical Unclonable Functions (PUFs) is a recently introduced method for remote authentication of objects. We present an extension of the protocol to enable the authentication of data: a verifier can check if received classical data was sent by the PUF holder. We call this

Field aligned flows driven by neutral puffing at MAST

Science.gov (United States)

Waters, I.; Frerichs, H.; Silburn, S.; Feng, Y.; Harrison, J.; Kirk, A.; Schmitz, O.

2018-06-01

Neutral deuterium gas puffing at the high field side of the mega ampere spherical tokamak (MAST) is shown to drive carbon impurity flows that are aligned with the trajectory of the magnetic field lines in the plasma scrape-off-layer. These impurity flows were directly imaged with emissions from C2+ ions at MAST by coherence imaging spectroscopy and were qualitatively reproduced in deuterium plasmas by modeling with the EMC3-EIRENE plasma edge fluid and kinetic neutral transport code. A reduced one-dimensional momentum and particle balance shows that a localized increase in the static plasma pressure in front of the neutral gas puff yields an acceleration of the plasma due to local ionization. Perpendicular particle transport yields a decay from which a parallel length scale can be determined. Parameter scans in EMC3-EIRENE were carried out to determine the sensitivity of the deuterium plasma flow phenomena to local fueling and diffusion parameters and it is found that these flows robustly form across a wide variety of plasma conditions. Finally, efforts to couple this behavior in the background plasma directly to the impurity flows observed experimentally in MAST using a trace impurity model are discussed. These results provide insight into the fueling and exhaust features at this pivotal point of the radial and parallel particle flux balance, which is a major part of the plasma fueling and exhaust characteristics in a magnetically confined fusion device.

The Puf family of RNA-binding proteins in plants: phylogeny, structural modeling, activity and subcellular localization

Directory of Open Access Journals (Sweden)

Tam Michael WC

2010-03-01

Full Text Available Abstract Background Puf proteins have important roles in controlling gene expression at the post-transcriptional level by promoting RNA decay and repressing translation. The Pumilio homology domain (PUM-HD is a conserved region within Puf proteins that binds to RNA with sequence specificity. Although Puf proteins have been well characterized in animal and fungal systems, little is known about the structural and functional characteristics of Puf-like proteins in plants. Results The Arabidopsis and rice genomes code for 26 and 19 Puf-like proteins, respectively, each possessing eight or fewer Puf repeats in their PUM-HD. Key amino acids in the PUM-HD of several of these proteins are conserved with those of animal and fungal homologs, whereas other plant Puf proteins demonstrate extensive variability in these amino acids. Three-dimensional modeling revealed that the predicted structure of this domain in plant Puf proteins provides a suitable surface for binding RNA. Electrophoretic gel mobility shift experiments showed that the Arabidopsis AtPum2 PUM-HD binds with high affinity to BoxB of the Drosophila Nanos Response Element I (NRE1 RNA, whereas a point mutation in the core of the NRE1 resulted in a significant reduction in binding affinity. Transient expression of several of the Arabidopsis Puf proteins as fluorescent protein fusions revealed a dynamic, punctate cytoplasmic pattern of localization for most of these proteins. The presence of predicted nuclear export signals and accumulation of AtPuf proteins in the nucleus after treatment of cells with leptomycin B demonstrated that shuttling of these proteins between the cytosol and nucleus is common among these proteins. In addition to the cytoplasmically enriched AtPum proteins, two AtPum proteins showed nuclear targeting with enrichment in the nucleolus. Conclusions The Puf family of RNA-binding proteins in plants consists of a greater number of members than any other model species studied to

SRAM-PUF Based on Selective Power-Up and Non-Destructive Scheme

OpenAIRE

Mispan, Mohd; Zwolinski, Mark; Halak, Basel

2016-01-01

Abstract. Research in hardware security, particularly on Physical Unclonable Functions (PUF) has attracted a lot of attention in recent years. PUFs provide primitives for implementing encryption/decryption and device fingerprinting. Though a wide range of solutions exists for PUF-based CMOS devices, the most investigated solutions today for weak PUF implementation are based on the use of random start-up values of SRAM, which offers the advantage of reusing memories that already exist in many ...

A robust SRAM-PUF key generation scheme based on polar codes

NARCIS (Netherlands)

Chen, Bin; Ignatenko, Tanya; Willems, Frans M.J.; Maes, Roel; van der Sluis, Erik; Selimis, Georgios

2017-01-01

Physical unclonable functions (PUFs) are relatively new security primitives used for device authentication and device-specific secret key generation. In this paper we focus on SRAM- PUFs. The SRAM-PUFs enjoy uniqueness and randomness properties stemming from the intrinsic randomness of SRAM memory

Physicochemical properties and antioxidant capacity of raw, roasted and puffed cacao beans.

Science.gov (United States)

Hu, SuJung; Kim, Byung-Yong; Baik, Moo-Yeol

2016-03-01

The antioxidant capacity and attributable bioactive compounds of puffed cacao beans were investigated. Roasting was carried out at 190°C for 15min and puffing was performed at 4-7kgf/cm(2). Cacao beans puffed at 4kgf/cm(2) showed the highest total polyphenols (23.16mgGAE/gsample) and total flavonoids (10.65mgCE/gsample) (pbeans reflected the total polyphenols and flavonoids measured. The quantities of theobromine, catechin, epicatechin, and procyanidin B2 were higher in cacao beans puffed at 4kgf/cm(2) than in roasted cacao beans. Puffed cacao beans received a good sensory score in flavor, but sourness increased as puffing pressure increased. Thus, these results suggest that, in cacao bean processing, puffing could be an alternative to roasting, which provide a rich taste and high antioxidant capacity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prescription Drug Profiles PUF

Data.gov (United States)

U.S. Department of Health & Human Services — This release contains the Prescription Drug Profiles Public Use Files (PUFs) drawn from Medicare prescription drug claims for the year of the date on which the...

High power electron accelerators for flue gas treatment

International Nuclear Information System (INIS)

Zimek, Z.

2011-01-01

Flue gas treatment process based on electron beam application for SO 2 and NO x removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

Semi-analytical study of the tokamak pedestal density profile in a single-null diverted plasma with puffing-recycling gas sources

Science.gov (United States)

Shi, Bingren

2010-10-01

The tokamak pedestal density structure is generally studied using a diffusion-dominant model. Recent investigations (Stacey and Groebner 2009 Phys. Plasmas 16 102504) from first principle based physics have shown a plausible existence of large inward convection in the pedestal region. The diffusion-convection equation with rapidly varying convection and diffusion coefficients in the near edge region and model puffing-recycling neutral particles is studied in this paper. A peculiar property of its solution for the existence of the large convection case is that the pedestal width of the density profile, qualitatively different from the diffusion-dominant case, depends mainly on the width of the inward convection and only weakly on the neutral penetration length and its injection position.

Semi-analytical study of the tokamak pedestal density profile in a single-null diverted plasma with puffing-recycling gas sources

Energy Technology Data Exchange (ETDEWEB)

Shi Bingren, E-mail: shibr@swip.ac.c [Southwestern Institute of Physics, PO Box 432, Chengdu, Sichuan 610041 (China)

2010-10-15

The tokamak pedestal density structure is generally studied using a diffusion-dominant model. Recent investigations (Stacey and Groebner 2009 Phys. Plasmas 16 102504) from first principle based physics have shown a plausible existence of large inward convection in the pedestal region. The diffusion-convection equation with rapidly varying convection and diffusion coefficients in the near edge region and model puffing-recycling neutral particles is studied in this paper. A peculiar property of its solution for the existence of the large convection case is that the pedestal width of the density profile, qualitatively different from the diffusion-dominant case, depends mainly on the width of the inward convection and only weakly on the neutral penetration length and its injection position.

High power electron accelerators for flue gas treatment

Energy Technology Data Exchange (ETDEWEB)

Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

2011-07-01

Flue gas treatment process based on electron beam application for SO{sub 2} and NO{sub x} removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

High fusion performance at high T i/T e in JET-ILW baseline plasmas with high NBI heating power and low gas puffing

Science.gov (United States)

Kim, Hyun-Tae; Sips, A. C. C.; Romanelli, M.; Challis, C. D.; Rimini, F.; Garzotti, L.; Lerche, E.; Buchanan, J.; Yuan, X.; Kaye, S.; contributors, JET

2018-03-01

This paper presents the transport analysis of high density baseline discharges in the 2016 experimental campaign of the Joint European Torus with the ITER-Like Wall (JET-ILW), where a significant increase in the deuterium-deuterium (D-D) fusion neutron rate (~2.8  ×  1016 s-1) was achieved with stable high neutral beam injection (NBI) powers of up to 28 MW and low gas puffing. Increase in T i exceeding T e were produced for the first time in baseline discharges despite the high electron density; this enabled a significant increase in the thermal fusion reaction rate. As a result, the new achieved record in fusion performance was much higher than the previous record in the same heating power baseline discharges, where T i  =  T e. In addition to the decreases in collisionality and the increases in ion heating fraction in the discharges with high NBI power, T i  >  T e can also be attributed to positive feedback between the high T i/T e ratio and stabilisation of the turbulent heat flux resulting from the ion temperature gradient driven mode. The high T i/T e ratio was correlated with high rotation frequency. Among the discharges with identical beam heating power, higher rotation frequencies were observed when particle fuelling was provided by low gas puffing and pellet injection. This reveals that particle fuelling played a key role for achieving high T i/T e, and the improved fusion performance.

Behavior of temperature dependent SRAM-PUFs, and consequences for secret-key capacity

NARCIS (Netherlands)

Kusters, C.J.; Ignatenko, T.; Willems, F.M.J.

2017-01-01

Physical Unclonable Functions (PUFs) are a resource for generating and sharing secret keys. The mutual information between two respective observations of the same PUF gives an upper bound for the achievable secret-key rate of a secret-sharing scheme that relies on this PUF. This mutual information

Role of the PufX protein in photosynthetic growth of Rhodobacter sphaeroides. 2. PufX is required for efficient ubiquinone/ubiquinol exchange between the reaction center QB site and the cytochrome bc1 complex.

Science.gov (United States)

Barz, W P; Verméglio, A; Francia, F; Venturoli, G; Melandri, B A; Oesterhelt, D

1995-11-21

The PufX membrane protein is essential for photosynthetic growth of Rhodobacter sphaeroides because it is required for multiple-turnover electron transfer under anaerobic conditions [see accompanying article; Barz, W. P., Francia, F., Venturoli, G., Melandri, B. A., Verméglio, A., & Oesterhelt, D. (1995) Biochemistry 34, 15235-15247]. In order to understand the molecular role of PufX, light-induced absorption spectroscopy was performed using a pufX- mutant, a pufX+ strain, and two suppressor mutants. We show that the reaction center (RC) requires PufX for its functionality under different redox conditions than the cytochrome bc1 complex: When the kinetics of flash-induced reduction of cytochrome b561 were monitored in chromatophores, we observed a requirement of PufX for turnover of the cytochrome bc1 complex only at high redox potential (Eh > 140 mV), suggesting a function of PufX in lateral ubiquinol transfer from the RC. In contrast, PufX is required for multiple turnover of the RC only under reducing conditions: When the Q pool was partially oxidized in vivo using oxygen or electron acceptors like dimethyl sulfoxide or trimethylamine N-oxide, the deletion of PufX had no effect on light-driven electron flow through the RC. Flash train experiments under anaerobic in vivo conditions revealed that RC photochemistry does not depend on PufX for the first two flash excitations. Following the third and subsequent flashes, however, efficient charge separation requires PufX, indicating an important role of PufX for fast Q/QH2 exchange at the QB site of the RC. We show that the Q/QH2 exchange rate is reduced approximately 500-fold by the deletion of PufX when the Q pool is nearly completely reduced, demonstrating an essential role of PufX for the access of ubiquinone to the QB site. The fast ubiquinone/ubiquinol exchange is partially restored by suppressor mutations altering the macromolecular antenna structure. These results suggest an indirect role of PufX in

Study of sorption behavior, shelf life and colour kinetics of vacuum puffed honey powder at accelerated storage conditions.

Science.gov (United States)

Devi, K Deepika; Paul, Sanjib Kr; Sahu, Jatindra K

2016-05-01

In the study, the storage life of vacuum puffed honey powder at accelerated storage environment (90 % relative humidity and 36 °C) was computed by determining the sticky-point moisture content as the critical parameter of the honey powder. The value of monolayer moisture content in the GAB model was calculated to be 0.081 kg water/kg dry solids by fitting water activity and moisture sorption data. Shelf life of the honey powder was predicted to be 222 days when the powder was packaged in aluminum foil-laminated polyethylene pouches with permeability value of 5.427X10(-8) kg/m(2)//day/Pa. Actual shelf life of honey powder was experimentally determined as 189 days and analysis of mean relative percent derivation modulus (Rd) and root mean square (RMS) established the accuracy and acceptability of the technique for the prediction of shelf life of honey powder. Overall colour deviation pattern followed first order reaction kinetics with rate constant (k1) as 0.037 day(-1). This study revealed overall colour difference of 18.1 till the end of shelf life with drastic change during initial storage period.

Heat damage and in vitro starch digestibility of puffed wheat kernels.

Science.gov (United States)

Cattaneo, Stefano; Hidalgo, Alyssa; Masotti, Fabio; Stuknytė, Milda; Brandolini, Andrea; De Noni, Ivano

2015-12-01

The effect of processing conditions on heat damage, starch digestibility, release of advanced glycation end products (AGEs) and antioxidant capacity of puffed cereals was studied. The determination of several markers arising from Maillard reaction proved pyrraline (PYR) and hydroxymethylfurfural (HMF) as the most reliable indices of heat load applied during puffing. The considerable heat load was evidenced by the high levels of both PYR (57.6-153.4 mg kg(-1) dry matter) and HMF (13-51.2 mg kg(-1) dry matter). For cost and simplicity, HMF looked like the most appropriate index in puffed cereals. Puffing influenced starch in vitro digestibility, being most of the starch (81-93%) hydrolyzed to maltotriose, maltose and glucose whereas only limited amounts of AGEs were released. The relevant antioxidant capacity revealed by digested puffed kernels can be ascribed to both the new formed Maillard reaction products and the conditions adopted during in vitro digestion. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Robust SRAM-PUF Key Generation Scheme Based on Polar Codes

OpenAIRE

Chen, Bin; Ignatenko, Tanya; Willems, Frans M. J.; Maes, Roel; van der Sluis, Erik; Selimis, Georgios

2017-01-01

Physical unclonable functions (PUFs) are relatively new security primitives used for device authentication and device-specific secret key generation. In this paper we focus on SRAM-PUFs. The SRAM-PUFs enjoy uniqueness and randomness properties stemming from the intrinsic randomness of SRAM memory cells, which is a result of manufacturing variations. This randomness can be translated into the cryptographic keys thus avoiding the need to store and manage the device cryptographic keys. Therefore...

MCBS Access to Care PUF

Data.gov (United States)

U.S. Department of Health & Human Services — The MCBS 2013 Access to Care public use file (MCBS PUF) provides the first publically available MCBS file for researchers interested in the health, health care use,...

Puffing, a novel coffee bean processing technique for the enhancement of extract yield and antioxidant capacity.

Science.gov (United States)

Kim, Wooki; Kim, Sang-Youn; Kim, Dae-Ok; Kim, Byung-Yong; Baik, Moo-Yeol

2018-02-01

Puffing of coffee beans, which induces heat- and pressure-derived physicochemical changes, was applied as an alternative to roasting. Roasted or puffed coffee beans with equivalent lightness values were compared. The moisture content was higher while the crude fat and protein compositions were lower in puffed beans than in roasted beans. The pH was lower and the acid content was higher in puffed beans than in roasted beans. The roasted beans exhibited greater specific volumes, while the puffed beans displayed greater extraction yields. The trigonelline and total phenolic contents were greater in puffed beans than in roasted beans resulting in an enhanced antioxidant capacity. Sensory evaluation of roasted and puffed coffee bean brews revealed that puffing did not affect the flavor or overall acceptance. The current study provides evidence that puffing is an alternative to roasting coffee beans with various benefits. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation and characterization of a PUF-domain of pumilio gene from ...

African Journals Online (AJOL)

STORAGESEVER

2009-03-20

Mar 20, 2009 ... study, a partial pumilio gene with complete PUF-domain in Bombyx mori has been ... Key words: Bombyx mori, pumilio, PUF-domain, RACE, germline stem cell. .... The first-strand cDNA was synthesized from 2 ug of total. RNA.

Institutional Provider and Beneficiary Summary PUF

Data.gov (United States)

U.S. Department of Health & Human Services — The CMS IPBS PUFs are aggregated files in which each record summarizes information for a particular institutional provider. An institutional provider refers to a...

Security of Quantum-Readout PUFs against quadrature based challenge estimation attacks

NARCIS (Netherlands)

Skoric, B.; Mosk, Allard; Pinkse, Pepijn Willemszoon Harry

2013-01-01

The concept of quantum-secure readout of Physical Unclonable Functions (PUFs) has recently been realized experimentally in an optical PUF system. We analyze the security of this system under the strongest type of classical attack: the challenge estimation attack. The adversary performs a measurement

Capacity of a dual enrollment system with two keys based on an SRAM-PUF

NARCIS (Netherlands)

Kusters, L.; Willems, F.M.J.

2018-01-01

We investigate the capacity of an SRAM-PUF based secrecy system that produces two secret keys during two consecutive enrollments. We determined the region of secret-key rates that are achievable and show that the total secret-key capacity is larger than for a single enrollment system. In our

Gas-filled capillaries for plasma-based accelerators

International Nuclear Information System (INIS)

Filippi, F; Anania, M P; Brentegani, E; Biagioni, A; Chiadroni, E; Ferrario, M; Pompili, R; Romeo, S; Cianchi, A; Zigler, A

2017-01-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented. (paper)

Gas-filled capillaries for plasma-based accelerators

Science.gov (United States)

Filippi, F.; Anania, M. P.; Brentegani, E.; Biagioni, A.; Cianchi, A.; Chiadroni, E.; Ferrario, M.; Pompili, R.; Romeo, S.; Zigler, A.

2017-07-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

Medicare FFS 30 Day Readmission Rate PUF

Data.gov (United States)

U.S. Department of Health & Human Services — The hospital readmission rate PUF presents nation-wide information about inpatient hospital stays that occurred within 30 days of a previous inpatient hospital stay...

Changes in puffing behavior among smokers who switched from tobacco to electronic cigarettes.

Science.gov (United States)

Lee, Yong Hee; Gawron, Michal; Goniewicz, Maciej Lukasz

2015-09-01

Nicotine intake from electronic cigarette (e-cigarettes) increases with user's experience. This suggests that smokers who switched from tobacco to electronic cigarettes compensate for nicotine over time to get as much nicotine as they need. One of the mechanisms by which smokers may compensate for nicotine is by modifying their puffing behavior. The aim of the study was to assess the changes in puffing behavior after switching from conventional to electronic cigarettes among regular smokers. Twenty smokers (11 female, aged 31±10, CPD 16±8, FTND 4±3, and exhaled CO 16±17 (mean±SD)) who were naïve to e-cigarettes participated in this study. They were asked to substitute their regular tobacco cigarettes with first generation e-cigarettes (labeled 18mg nicotine) for two weeks. Puffing topography (number of puffs, puff volume, intervals between puffs, and average puff flow rate) was measured at the initial use (baseline), as well as after one and two weeks of product use. We tested changes in puffing topography outcomes using repeated measures ANOVA. We found that after one week of using e-cigarettes, participants significantly increased the average time they puffed on e-cigarettes from 2.2±0.1 (mean±SEM) to 3.1±0.3s (pe-cigarette use (preason for changing puffing behavior is to compensate for less efficient nicotine delivery from e-cigarettes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Role of recycling flux in gas fuelling in the Large Helical Device

International Nuclear Information System (INIS)

Miyazawa, J.; Masuzaki, S.; Yamada, H.

2004-01-01

The 'effective' fuelling efficiency of hydrogen gas puffing ranges from 10% to 50% in the Large Helical Device. A local increase in neutral particle pressure at the gas puff port was measured in the experiment. The pressure increase rate corresponds to ∼ 10% of the gas puff flux. The other 90% of the gas puff flux increases the density and/or the plasma outflow. A particle balance model reveals that the recycling flux estimated from the particle flux on the divertor plates increases during the gas puffing. It is shown that the high effective fuelling efficiency is possibly due to the large recycling flux. At the limit of small recycling flux, the effective fuelling efficiency decreases to ∼10%. In the helium gas puff discharge, the effective fuelling efficiency is larger than the hydrogen gas puffing and approaches 100%. This can be related to the large recycling coefficient of more than 0.95. (author)

Basic Stand Alone Carrier Line Items PUF

Data.gov (United States)

U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

Security of helper data Schemes for SRAM-PUF in multiple enrollment scenarios

NARCIS (Netherlands)

Kusters, C.J.; Ignatenko, T.; Maes, R.; van der Sluis, E.; Selimis, G.; Willems, F.M.J.

2017-01-01

Fuzzy commitment and syndrome-based schemes are two well-known helper data schemes used to bind and generate, respectively, a secret key to/from SRAM-PUF observations. To allow the decoder to reconstruct this secret key from a new (verification) observation of an SRAM-PUF, an encoder has to generate

Compact toroid formation, compression, and acceleration

International Nuclear Information System (INIS)

Degnan, J.H.; Peterkin, R.E. Jr.; Baca, G.P.; Beason, J.D.; Bell, D.E.; Dearborn, M.E.; Dietz, D.; Douglas, M.R.; Englert, S.E.; Englert, T.J.; Hackett, K.E.; Holmes, J.H.; Hussey, T.W.; Kiuttu, G.F.; Lehr, F.M.; Marklin, G.J.; Mullins, B.W.; Price, D.W.; Roderick, N.F.; Ruden, E.L.; Sovinec, C.R.; Turchi, P.J.; Bird, G.; Coffey, S.K.; Seiler, S.W.; Chen, Y.G.; Gale, D.; Graham, J.D.; Scott, M.; Sommars, W.

1993-01-01

Research on forming, compressing, and accelerating milligram-range compact toroids using a meter diameter, two-stage, puffed gas, magnetic field embedded coaxial plasma gun is described. The compact toroids that are studied are similar to spheromaks, but they are threaded by an inner conductor. This research effort, named MARAUDER (Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation), is not a magnetic confinement fusion program like most spheromak efforts. Rather, the ultimate goal of the present program is to compress toroids to high mass density and magnetic field intensity, and to accelerate the toroids to high speed. There are a variety of applications for compressed, accelerated toroids including fast opening switches, x-radiation production, radio frequency (rf) compression, as well as charge-neutral ion beam and inertial confinement fusion studies. Experiments performed to date to form and accelerate toroids have been diagnosed with magnetic probe arrays, laser interferometry, time and space resolved optical spectroscopy, and fast photography. Parts of the experiment have been designed by, and experimental results are interpreted with, the help of two-dimensional (2-D), time-dependent magnetohydrodynamic (MHD) numerical simulations. When not driven by a second discharge, the toroids relax to a Woltjer--Taylor equilibrium state that compares favorably to the results of 2-D equilibrium calculations and to 2-D time-dependent MHD simulations. Current, voltage, and magnetic probe data from toroids that are driven by an acceleration discharge are compared to 2-D MHD and to circuit solver/slug model predictions. Results suggest that compact toroids are formed in 7--15 μsec, and can be accelerated intact with material species the same as injected gas species and entrained mass ≥1/2 the injected mass

An Approach to Function Annotation for Proteins of Unknown Function (PUFs in the Transcriptome of Indian Mulberry.

Directory of Open Access Journals (Sweden)

K H Dhanyalakshmi

Full Text Available The modern sequencing technologies are generating large volumes of information at the transcriptome and genome level. Translation of this information into a biological meaning is far behind the race due to which a significant portion of proteins discovered remain as proteins of unknown function (PUFs. Attempts to uncover the functional significance of PUFs are limited due to lack of easy and high throughput functional annotation tools. Here, we report an approach to assign putative functions to PUFs, identified in the transcriptome of mulberry, a perennial tree commonly cultivated as host of silkworm. We utilized the mulberry PUFs generated from leaf tissues exposed to drought stress at whole plant level. A sequence and structure based computational analysis predicted the probable function of the PUFs. For rapid and easy annotation of PUFs, we developed an automated pipeline by integrating diverse bioinformatics tools, designated as PUFs Annotation Server (PUFAS, which also provides a web service API (Application Programming Interface for a large-scale analysis up to a genome. The expression analysis of three selected PUFs annotated by the pipeline revealed abiotic stress responsiveness of the genes, and hence their potential role in stress acclimation pathways. The automated pipeline developed here could be extended to assign functions to PUFs from any organism in general. PUFAS web server is available at http://caps.ncbs.res.in/pufas/ and the web service is accessible at http://capservices.ncbs.res.in/help/pufas.

Effects of chemical composite, puffing temperature and intermediate moisture content on physical properties of potato and apple slices

Science.gov (United States)

Tabtaing, S.; Paengkanya, S.; Tanthong, P.

2017-09-01

Puffing technique is the process that can improve texture and volumetric of crisp fruit and vegetable. However, the effect of chemical composite in foods on puffing characteristics is still lack of study. Therefore, potato and apple slices were comparative study on their physical properties. Potato and apple were sliced into 2.5 mm thickness and 2.5 cm in diameter. Potato slices were treated by hot water for 2 min while apple slices were not treatment. After that, they were dried in 3 steps. First step, they were dried by hot air at temperature of 90°C until their moisture content reached to 30, 40, and 50 % dry basis. Then they were puffed by hot air at temperature of 130, 150, and 170°C for 2 min. Finally, they were dried again by hot air at temperature of 90°C until their final moisture content reached to 4% dry basis. The experimental results showed that chemical composite of food affected on physical properties of puffed product. Puffed potato had higher volume ratio than those puffed apple because potato slices contains starch. The higher starch content provided more hard texture of potato than those apples. Puffing temperature and moisture content strongly affected on the color, volume ratio, and textural properties of puffed potato slices. In addition, the high drying rate of puffed product observed at high puffing temperature and higher moisture content.

Shared Savings Program Accountable Care Organizations PUF

Data.gov (United States)

U.S. Department of Health & Human Services — SSP ACO PUF - To address the increasing number of requests for SSP ACO data, the Centers for Medicare (CM) has created a standard analytical file that CMS can use to...

Heat transfer to accelerating gas flows

International Nuclear Information System (INIS)

Kennedy, T.D.A.

1978-01-01

The development of fuels for gas-cooled reactors has resulted in a number of 'gas loop' experiments in materials-testing research reactors. In these experiments, efforts are made to reproduce the conditions expected in gas-cooled power reactors. Constant surface temperatures are sought over a short (300 mm) fuelled length, and because of entrance effects, an accelerating flow is required to increase the heat transfer down-stream from the entrance. Strong acceleration of a gas stream will laminarise the flow even at Reynolds Numbers up to 50000, far above values normally associated with laminar flow. A method of predicting heat transfer in this situation is presented here. An integral method is used to find the velocity profile; this profile is then used in an explicit finite-difference solution of the energy equation to give a temperature profile and resultant heat-transfer coefficient values. The Kline criterion, which compares viscous and disruptive forces, is used to predict whether the flow will be laminar. Experimental results are compared with predictions, and good agreement is found to exist. (author)

Basic Stand Alone Skilled Nursing Facility Beneficiary PUF

Data.gov (United States)

U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Skilled Nursing Facility (SNF) Beneficiary Public Use Files (PUF) with information from Medicare SNF claims. The...

Squalene Extraction by Supercritical Fluids from Traditionally Puffed Amaranthus hypochondriacus Seeds

Directory of Open Access Journals (Sweden)

Teresa Rosales-García

2017-01-01

Full Text Available Extraction of squalene, a potent natural antioxidant, from puffed A. hypochondriacus seeds was performed by supercritical fluid extraction (SCFE; besides, to have a blank for comparison, extraction was performed also by Soxhlet method using organic solvents (hexane. Chemical proximal composition and seed morphology were determined in raw, puffed, and SCFE-extracted seeds. Extracts were obtained with a 500 mL capacity commercial supercritical extractor and performed between 10 and 30 MPa at 313, 323, and 333 K under constant CO2 flow of 0.18 kg CO2/h during 8 h. The squalene content was determined and the fatty acids present in the extracts were identified by GC-MS. The extract obtained by SCFE from puffed amaranth seeds reached 460 ± 28.1 g/kg squalene in oily extract at 313 K/20 MPa.

Basic Stand Alone Medicare DME Line Items PUF

Data.gov (United States)

U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Durable Medical Equipment (DME) Line Items Public Use Files (PUF) with information from Medicare DME claims. The...

Schmitt-Trigger-based Recycling Sensor and Robust and High-Quality PUFs for Counterfeit IC Detection

OpenAIRE

Lin, Cheng-Wei; Jang, Jae-Won; Ghosh, Swaroop

2015-01-01

We propose Schmitt-Trigger (ST) based recycling sensor that are tailored to amplify the aging mechanisms and detect fine grained recycling (minutes to seconds). We exploit the susceptibility of ST to process variations to realize high-quality arbiter PUF. Conventional SRAM PUF suffer from environmental fluctuation-induced bit flipping. We propose 8T SRAM PUF with a back-to-back PMOS latch to improve robustness by 4X. We also propose a low-power 7T SRAM with embedded Magnetic Tunnel Junction (...

Accelerated Fractional Ventilation Imaging with Hyperpolarized Gas MRI

Science.gov (United States)

Emami, Kiarash; Xu, Yinan; Hamedani, Hooman; Profka, Harrilla; Kadlecek, Stephen; Xin, Yi; Ishii, Masaru; Rizi, Rahim R.

2013-01-01

PURPOSE To investigate the utility of accelerated imaging to enhance multi-breath fractional ventilation (r) measurement accuracy using HP gas MRI. Undersampling shortens the breath-hold time, thereby reducing the O2-induced signal decay and allows subjects to maintain a more physiologically relevant breathing pattern. Additionally it may improve r estimation accuracy by reducing RF destruction of HP gas. METHODS Image acceleration was achieved by using an 8-channel phased array coil. Undersampled image acquisition was simulated in a series of ventilation images and images were reconstructed for various matrix sizes (48–128) using GRAPPA. Parallel accelerated r imaging was also performed on five mechanically ventilated pigs. RESULTS Optimal acceleration factor was fairly invariable (2.0–2.2×) over the range of simulated resolutions. Estimation accuracy progressively improved with higher resolutions (39–51% error reduction). In vivo r values were not significantly different between the two methods: 0.27±0.09, 0.35±0.06, 0.40±0.04 (standard) versus 0.23±0.05, 0.34±0.03, 0.37±0.02 (accelerated); for anterior, medial and posterior slices, respectively, whereas the corresponding vertical r gradients were significant (P fractional ventilation measurement with HP gas MRI. PMID:23400938

Photosynthesis Is Widely Distributed among Proteobacteria as Demonstrated by the Phylogeny of PufLM Reaction Center Proteins

Directory of Open Access Journals (Sweden)

Johannes F. Imhoff

2018-01-01

Full Text Available Two different photosystems for performing bacteriochlorophyll-mediated photosynthetic energy conversion are employed in different bacterial phyla. Those bacteria employing a photosystem II type of photosynthetic apparatus include the phototrophic purple bacteria (Proteobacteria, Gemmatimonas and Chloroflexus with their photosynthetic relatives. The proteins of the photosynthetic reaction center PufL and PufM are essential components and are common to all bacteria with a type-II photosynthetic apparatus, including the anaerobic as well as the aerobic phototrophic Proteobacteria. Therefore, PufL and PufM proteins and their genes are perfect tools to evaluate the phylogeny of the photosynthetic apparatus and to study the diversity of the bacteria employing this photosystem in nature. Almost complete pufLM gene sequences and the derived protein sequences from 152 type strains and 45 additional strains of phototrophic Proteobacteria employing photosystem II were compared. The results give interesting and comprehensive insights into the phylogeny of the photosynthetic apparatus and clearly define Chromatiales, Rhodobacterales, Sphingomonadales as major groups distinct from other Alphaproteobacteria, from Betaproteobacteria and from Caulobacterales (Brevundimonas subvibrioides. A special relationship exists between the PufLM sequences of those bacteria employing bacteriochlorophyll b instead of bacteriochlorophyll a. A clear phylogenetic association of aerobic phototrophic purple bacteria to anaerobic purple bacteria according to their PufLM sequences is demonstrated indicating multiple evolutionary lines from anaerobic to aerobic phototrophic purple bacteria. The impact of pufLM gene sequences for studies on the environmental diversity of phototrophic bacteria is discussed and the possibility of their identification on the species level in environmental samples is pointed out.

Synthesis of plutonium trifluoride by hydro-fluorination and novel thermodynamic data for the PuF3-LiF system

Science.gov (United States)

Tosolin, A.; Souček, P.; Beneš, O.; Vigier, J.-F.; Luzzi, L.; Konings, R. J. M.

2018-05-01

PuF3 was synthetized by hydro-fluorination of PuO2 and subsequent reduction of the product by hydrogenation. The obtained PuF3 was analysed by X-Ray Diffraction (XRD) and found phase-pure. High purity was also confirmed by the melting point analysis using Differential Scanning Calorimetry (DSC). PuF3 was then used for thermodynamic assessment of the PuF3-LiF system. Phase equilibrium points and enthalpy of fusion of the eutectic composition were measured by DSC. XRD analyses of selected samples after DSC measurement confirm that after solidification from the liquid, the system returns to a mixture of LiF and PuF3.

An Anti-Electromagnetic Attack PUF Based on a Configurable Ring Oscillator for Wireless Sensor Networks.

Science.gov (United States)

Lu, Zhaojun; Li, Dongfang; Liu, Hailong; Gong, Mingyang; Liu, Zhenglin

2017-09-15

Wireless sensor networks (WSNs) are an emerging technology employed in some crucial applications. However, limited resources and physical exposure to attackers make security a challenging issue for a WSN. Ring oscillator-based physical unclonable function (RO PUF) is a potential option to protect the security of sensor nodes because it is able to generate random responses efficiently for a key extraction mechanism, which prevents the non-volatile memory from storing secret keys. In order to deploy RO PUF in a WSN, hardware efficiency, randomness, uniqueness, and reliability should be taken into account. Besides, the resistance to electromagnetic (EM) analysis attack is important to guarantee the security of RO PUF itself. In this paper, we propose a novel architecture of configurable RO PUF based on exclusive-or (XOR) gates. First, it dramatically increases the hardware efficiency compared with other types of RO PUFs. Second, it mitigates the vulnerability to EM analysis attack by placing the adjacent RO arrays in accordance with the cosine wave and sine wave so that the frequency of each RO cannot be detected. We implement our proposal in XINLINX A-7 field programmable gate arrays (FPGAs) and conduct a set of experiments to evaluate the quality of the responses. The results show that responses pass the National Institute of Standards and Technology (NIST) statistical test and have good uniqueness and reliability under different environments. Therefore, the proposed configurable RO PUF is suitable to establish a key extraction mechanism in a WSN.

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)

Novel gas target for laser wakefield accelerators

Science.gov (United States)

Aniculaesei, C.; Kim, Hyung Taek; Yoo, Byung Ju; Oh, Kyung Hwan; Nam, Chang Hee

2018-02-01

A novel gas target for interactions between high power lasers and gaseous medium, especially for laser wakefield accelerators, has been designed, manufactured, and characterized. The gas target has been designed to provide a uniform density profile along the central gas cell axis by combining a gas cell and slit nozzle. The gas density has been tuned from ˜1017 atoms/cm3 to ˜1019 atoms/cm3 and the gas target length can be varied from 0 to 10 cm; both changes can be made simultaneously while keeping the uniform gas profile. The gas density profile inside the gas cell has been measured using interferometry and validated using computational fluid dynamics.

A novel puf-A gene predicted from evolutionary analysis is involved in the development of eyes and primordial germ-cells.

Directory of Open Access Journals (Sweden)

Ming-Wei Kuo

Full Text Available Although the human genome project has been completed for some time, the issue of the number of transcribed genes with identifiable biological functions remains unresolved. We used zebrafish as a model organism to study the functions of Ka/Ks-predicted novel human exons, which were identified from a comparative evolutionary genomics analysis.In this study, a novel gene, designated as puf-A, was cloned and functionally characterized, and its homologs in zebrafish, mouse, and human were identified as one of the three homolog clusters which were consisted of 14 related proteins with Puf repeats. Computer modeling of human Puf-A structure and a pull-down assay for interactions with RNA targets predicted that it was a RNA-binding protein. Specifically, Puf-A contained a special six Puf-repeat domain, which constituted a unique superhelix half doughnut-shaped Puf domain with a topology similar to, but different from the conventional eight-repeat Pumilio domain. Puf-A transcripts were uniformly distributed in early embryos, but became restricted primarily to eyes and ovaries at a later stage of development. In mice, puf-A expression was detected primarily in retinal ganglion and pigmented cells. Knockdown of puf-A in zebrafish embryos resulted in microphthalmia, a small head, and abnormal primordial germ-cell (PGC migration. The latter was confirmed by microinjecting into embryos puf-A siRNA containing nanos 3' UTR that expressed in PGC only. The importance of Puf-A in the maturation of germline stem cells was also implicated by its unique expression in the most primitive follicles (stage I in adult ovaries, followed by a sharp decline of expression in later stages of folliculogenesis. Taken together, our study shows that puf-A plays an important role not only in eye development, but also in PGC migration and the specification of germ cell lineage. These studies represent an exemplary implementation of a unique platform to uncover unknown function(s of

Development, validation and application of a device to measure e-cigarette users’ puffing topography

Science.gov (United States)

Cunningham, Anthony; Slayford, Sandra; Vas, Carl; Gee, Jodie; Costigan, Sandra; Prasad, Krishna

2016-01-01

With the rapidly rising popularity and substantial evolution of electronic cigarettes (e-cigarettes) in the past 5–6 years, how these devices are used by vapers and consumers’ exposure to aerosol emissions need to be understood. We used puffing topography to measure directly product use. We adapted a cigarette puffing topography device for use with e-cigarettes. We performed validation using air and e-cigarette aerosol under multiple regimes. Consumer puffing topography was measured for 60 vapers provided with rechargeable “cig-a-like” or larger button-activated e-cigarettes, to use ad-libitum in two sessions. Under all regimes, air puff volumes were within 1 mL of the target and aerosol volumes within 5 mL for all device types, serving to validate the device. Vapers’ mean puff durations (2.0 s and 2.2 s) were similar with both types of e-cigarette, but mean puff volumes (52.2 mL and 83.0 mL) and mean inter-puff intervals (23.2 s and 29.3 s) differed significantly. The differing data show that product characteristics influence puffing topography and, therefore, the results obtained from a given e-cigarette might not read across to other products. Understanding the factors that affect puffing topography will be important for standardising testing protocols for e-cigarette emissions. PMID:27721496

Investigating SRAM PUFs in large CPUs and GPUs

NARCIS (Netherlands)

Aubel, Van P.; Bernstein, D.J.; Niederhagen, R.F.

2015-01-01

Physically unclonable functions (PUFs) provide data that can be used for cryptographic purposes: on the one hand randomness for the initialization of random-number generators; on the other hand individual fingerprints for unique identification of specific hardware components. However, today's

Investigating SRAM PUFs in large CPUs and GPUs

NARCIS (Netherlands)

Aubel, Van P.; Bernstein, D.J.; Niederhagen, R.F.; Chakraborty, R.S.; Schwabe, P.; Solworth, J.

2015-01-01

Physically unclonable functions (PUFs) provide data that can be used for cryptographic purposes: on the one hand randomness for the initialization of random-number generators; on the other hand individual fingerprints for unique identification of specific hardware components. However, today’s

Characteristics of x-ray radiation from a gas-puff z-pinch plasma

International Nuclear Information System (INIS)

Akiyama, N.; Takasugi, K.

2002-01-01

Characteristics of x-ray radiation from Ar gas-puff z-pinch plasma have been investigated by changing delay time of discharge from gas puffing. Intense cloud structure of x-ray image was observed at small delay time region, but the total x-ray signal was not so intense. The x-ray signal increased with increasing the delay time, and hot spots of x-ray image also became intense. Electron temperature was evaluated from x-ray spectroscopic data, and no significant difference in temperature was observed. (author)

Effect of gas injection during LH wave coupling at ITER-relevant plasma-wall distances in JET

International Nuclear Information System (INIS)

Ekedahl, A; Goniche, M; Basiuk, V; Delpech, L; Imbeaux, F; Joffrin, E; Loarer, T; Rantamaeki, K; Mailloux, J; Alper, B; Baranov, Y; Beaumont, P; Corrigan, G; Erents, K; Hawkes, N; McDonald, D; Petrzilka, V; Granucci, G; Hobirk, J; Kirov, K

2009-01-01

Good coupling of lower hybrid (LH) waves has been demonstrated in different H-mode scenarios in JET, at high triangularity (δ ∼ 0.4) and at large distance between the last closed flux surface and the LH launcher (up to 15 cm). Local gas injection of D 2 in the region magnetically connected to the LH launcher is used for increasing the local density in the scrape-off layer (SOL). Reciprocating Langmuir probe measurements magnetically connected to the LH launcher indicate that the electron density profile flattens in the far SOL during gas injection and LH power application. Some degradation in normalized H-mode confinement, as given by the H98(y,2)-factor, could be observed at high gas injection rates in these scenarios, but this was rather due to total gas injection and not specifically to the local gas puffing used for LH coupling. Furthermore, experiments carried out in L-mode plasmas in order to evaluate the effect on the LH current drive efficiency, when using local gas injection to improve the coupling, indicate only a small degradation (ΔI LH /I LH ∼ 15%). This effect is largely compensated by the improvement in coupling and thus increase in coupled power when using gas puffing.

Analysis of divertor asymmetry using a simple five-point model

International Nuclear Information System (INIS)

Hayashi, Nobuhiko; Takizuka, Tomonori; Hatayama, Akiyoshi; Ogasawara, Masatada.

1997-03-01

A simple five-point model of the scrape-off layer (SOL) plasma outside the separatrix of a diverted tokamak has been developed to study the inside/outside divertor asymmetry. The SOL current, gas pumping/puffing in the divertor region, and divertor plate biasing are included in this model. Gas pumping/puffing and biasing are shown to control divertor asymmetry. In addition, the SOL current is found to form asymmetric solutions without external controls of gas pumping/puffing and biasing. (author)

Parameters' influence estimation on Puf supply and demand in transitional period from LWR to FBR in Japan

International Nuclear Information System (INIS)

Kobayashi, Hiroaki; Ohta, Hirokazu; Inoue, Tadashi

2009-01-01

Plutonium fissile (Puf) amounts to balance supply and demand during transition period were evaluated with different parameters. Estimated total Puf demand in transitional period was sensitive to deployment speed of FBR. Because FBRs will be deployed as replacements of old LWRs for keeping total capacity, deployment history of existing LWRs should be taken into consideration. According to the estimation, LWR fuel burnup and utilized capacity are not big issue. Because certain amount of LWR spent fuel will remain in early phase of transitional period, there is enough time for preparing Puf supply. On the other hand, FBR fuel cycle time (SF cooling time + fuel fabrication time) have large impact on Puf supply. Fuel cycle technologies including transportation for applying to short cooling spent fuels should be developed. (author)

Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides.

Science.gov (United States)

Adams, Peter G; Mothersole, David J; Ng, Irene W; Olsen, John D; Hunter, C Neil

2011-09-01

In the model photosynthetic bacterium Rhodobacter sphaeroides domains of light-harvesting 2 (LH2) complexes surround and interconnect dimeric reaction centre-light-harvesting 1-PufX (RC-LH1-PufX) 'core' complexes, forming extensive networks for energy transfer and trapping. These complexes are housed in spherical intracytoplasmic membranes (ICMs), which are assembled in a stepwise process where biosynthesis of core complexes tends to dominate the early stages of membrane invagination. The kinetics of LH2 assembly were measured in PufX mutants that assemble monomeric core complexes, as a consequence of either a twelve-residue N-terminal truncation of PufX (PufXΔ12) or the complete removal of PufX (PufX(-)). Lower rates of LH2 assembly and retarded maturation of membrane invagination were observed for the larger and less curved ICM from the PufX(-) mutant, consistent with the proposition that local membrane curvature, initiated by arrays of bent RC-LH1-PufX dimers, creates a favourable environment for stable assembly of LH2 complexes. Transmission electron microscopy and high-resolution atomic force microscopy were used to examine ICM morphology and membrane protein organisation in these mutants. Some partitioning of core and LH2 complexes was observed in PufX(-) membranes, resulting in locally ordered clusters of monomeric RC-LH1 complexes. The distribution of core and LH2 complexes in the three types of membrane examined is consistent with previous models of membrane curvature and domain formation (Frese et al., 2008), which demonstrated that a combination of crowding and asymmetries in sizes and shapes of membrane protein complexes drives membrane organisation. 2011 Elsevier B.V. All rights reserved.

Puffing of okara/rice blends using a rice cake machine.

Science.gov (United States)

Xie, M; Huff, H; Hsieh, F; Mustapha, A

2008-10-01

Okara is the insoluble byproduct of soymilk and tofu manufactures. It is cheap, high in nutrients, and possesses great potential to be applied to functional human foods. In this study, a puffed okara/rice cake product was developed with blends of okara pellets and parboiled rice. Consumer preference and acceptance tests were conducted for the product. Okara pellets were prepared by grinding the strands obtained from extruding a mixture of dried okara and rice flour (3:2, w/w) with a twin-screw extruder. Okara pellets and parboiled rice were blended in 4 ratios, 90:10, 70:30, 40:60, and 0:100 (w/w), and tempered to 14% and 17% moisture. The blends were puffed at 221, 232, and 243 degrees C for 4, 5, or 6 s. The okara/rice cakes were evaluated for specific volume (SPV), texture, color, and percent weight loss after tumbling. Overall, the decrease in okara content and increase in moisture, heating temperature and time led to greater specific volume (SPV) and hardness, lighter color, and lower percent weight loss after tumbling. The consumer tests indicated that the okara/rice cake containing 70% okara pellets was preferred and the 90% one was liked the least. The possible drivers of liking for the puffed okara/rice cakes could be the okara content, hardness, SPV, bright color, and percent weight loss after tumbling.

Two-stage light-gas magnetoplasma accelerator for hypervelocity impact simulation

International Nuclear Information System (INIS)

Khramtsov, P P; Vasetskij, V A; Makhnach, A I; Grishenko, V M; Chernik, M Yu; Shikh, I A; Doroshko, M V

2016-01-01

The development of macroparticles acceleration methods for high-speed impact simulation in a laboratory is an actual problem due to increasing of space flights duration and necessity of providing adequate spacecraft protection against micrometeoroid and space debris impacts. This paper presents results of experimental study of a two-stage light- gas magnetoplasma launcher for acceleration of a macroparticle, in which a coaxial plasma accelerator creates a shock wave in a high-pressure channel filled with light gas. Graphite and steel spheres with diameter of 2.5-4 mm were used as a projectile and were accelerated to the speed of 0.8-4.8 km/s. A launching of particle occurred in vacuum. For projectile velocity control the speed measuring method was developed. The error of this metod does not exceed 5%. The process of projectile flight from the barrel and the process of a particle collision with a target were registered by use of high-speed camera. The results of projectile collision with elements of meteoroid shielding are presented. In order to increase the projectile velocity, the high-pressure channel should be filled with hydrogen. However, we used helium in our experiments for safety reasons. Therefore, we can expect that the range of mass and velocity of the accelerated particles can be extended by use of hydrogen as an accelerating gas. (paper)

Two-stage light-gas magnetoplasma accelerator for hypervelocity impact simulation

Science.gov (United States)

Khramtsov, P. P.; Vasetskij, V. A.; Makhnach, A. I.; Grishenko, V. M.; Chernik, M. Yu; Shikh, I. A.; Doroshko, M. V.

2016-11-01

The development of macroparticles acceleration methods for high-speed impact simulation in a laboratory is an actual problem due to increasing of space flights duration and necessity of providing adequate spacecraft protection against micrometeoroid and space debris impacts. This paper presents results of experimental study of a two-stage light- gas magnetoplasma launcher for acceleration of a macroparticle, in which a coaxial plasma accelerator creates a shock wave in a high-pressure channel filled with light gas. Graphite and steel spheres with diameter of 2.5-4 mm were used as a projectile and were accelerated to the speed of 0.8-4.8 km/s. A launching of particle occurred in vacuum. For projectile velocity control the speed measuring method was developed. The error of this metod does not exceed 5%. The process of projectile flight from the barrel and the process of a particle collision with a target were registered by use of high-speed camera. The results of projectile collision with elements of meteoroid shielding are presented. In order to increase the projectile velocity, the high-pressure channel should be filled with hydrogen. However, we used helium in our experiments for safety reasons. Therefore, we can expect that the range of mass and velocity of the accelerated particles can be extended by use of hydrogen as an accelerating gas.

OEDGE modeling of plasma contamination efficiency of Ar puffing from different divertor locations in EAST

Science.gov (United States)

Pengfei, ZHANG; Ling, ZHANG; Zhenwei, WU; Zong, XU; Wei, GAO; Liang, WANG; Qingquan, YANG; Jichan, XU; Jianbin, LIU; Hao, QU; Yong, LIU; Juan, HUANG; Chengrui, WU; Yumei, HOU; Zhao, JIN; J, D. ELDER; Houyang, GUO

2018-04-01

Modeling with OEDGE was carried out to assess the initial and long-term plasma contamination efficiency of Ar puffing from different divertor locations, i.e. the inner divertor, the outer divertor and the dome, in the EAST superconducting tokamak for typical ohmic plasma conditions. It was found that the initial Ar contamination efficiency is dependent on the local plasma conditions at the different gas puff locations. However, it quickly approaches a similar steady state value for Ar recycling efficiency >0.9. OEDGE modeling shows that the final equilibrium Ar contamination efficiency is significantly lower for the more closed lower divertor than that for the upper divertor.

Dynamic behavior of IREB in a collective ion acceleration experiment

International Nuclear Information System (INIS)

Fine, T.A.; Rhee, M.J.

1989-01-01

The authors report an experimental study of dynamic behavior of net current in conjunction with collective ion acceleration. In the presence of neutral gas, either puffed in or released from the anode foil, the IREB injected is subject to the charge and current neutralizations, resulting in a complicated time and space dependent beam distribution in the drift tube. To investigate the dynamic behavior of the current in the drift tube, typically a 0.5 MeV, 70 kA, 100 ns electron beam of 2.54 cm diam is injected through a foil anode into a drift tube of 15 cm diam. Reproducibility of experiment was improved by using a specially designed anode system with a foil changer which allowed the production of many shots of high current electron beam without disturbing the vacuum condition. The net currents were measured by a Rogowski coil built in the anode system, and a movable Faraday cup along the drift tube. The ions accelerated were diagnosed mainly by a Thomson spectrometer system placed at the end of the drift tube

A new gas stripper system for BARC-TIFR Pelletron Accelerator facility: installation and preliminary results

International Nuclear Information System (INIS)

Sharma, S.C.; Ninawe, N.G.; Yadav, M.L.; Ekambaram, M.; Ramjilal; Matkar, U.V.; Ansari, Q.N.; Lokare, R.N.; Ramlal; Gupta, A.K.; Bhagwat, P.V.; Pillay, R.G.

2009-01-01

The gas-stripper plays a key role in stripping the heavy and molecular ion beams in a tandem accelerator. Efficiency of gas stripper depends on its supporting vacuum pumps. A new recirculating turbo molecular pump-based gas stripper has been installed in the high voltage terminal of Pelletron Accelerator. Re-circulating the stripper gas reduces the flow of gas into the accelerating tubes reducing the transmission losses. Preliminary results obtained using the new gas stripper system are discussed. (author)

3D printing of gas jet nozzles for laser-plasma accelerators

Energy Technology Data Exchange (ETDEWEB)

Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École Polytechnique, Université Paris-Saclay, 828 Boulevard des Maréchaux, 91762 Palaiseau Cedex (France)

2016-07-15

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the SALLE JAUNE terawatt laser at Laboratoire d’Optique Appliquée.

Structure of the dimeric PufX-containing core complex of Rhodobacter blasticus by in situ atomic force microscopy.

Science.gov (United States)

Scheuring, Simon; Busselez, Johan; Lévy, Daniel

2005-01-14

We have studied photosynthetic membranes of wild type Rhodobacter blasticus, a closely related strain to the well studied Rhodobacter sphaeroides, using atomic force microscopy. High-resolution atomic force microscopy topographs of both cytoplasmic and periplasmic surfaces of LH2 and RC-LH1-PufX (RC, reaction center) complexes were acquired in situ. The LH2 is a nonameric ring inserted into the membrane with the 9-fold axis perpendicular to the plane. The core complex is an S-shaped dimer composed of two RCs, each encircled by 13 LH1 alpha/beta-heterodimers, and two PufXs. The LH1 assembly is an open ellipse with a topography-free gap of approximately 25 A. The two PufXs, one of each core, are located at the dimer center. Based on our data, we propose a model of the core complex, which provides explanation for the PufX-induced dimerization of the Rhodobacter core complex. The QB site is located facing a approximately 25-A wide gap within LH1, explaining the PufX-favored quinone passage in and out of the core complex.

Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration.

Science.gov (United States)

Brandi, F; Giammanco, F; Conti, F; Sylla, F; Lambert, G; Gizzi, L A

2016-08-01

The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10(19) cm(-3) range well suited for LWFA.

Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

Energy Technology Data Exchange (ETDEWEB)

Brandi, F., E-mail: fernando.brandi@ino.it [Intense Laser Irradiation Laboratory (ILIL), Istituto Nazionale di Ottica (INO-CNR), Via Moruzzi 1, 56124 Pisa (Italy); Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Giammanco, F.; Conti, F. [Dipartimento di Fisica, Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Plasma Diagnostics and Technologies Ltd., via Matteucci n.38/D, 56124 Pisa (Italy); Sylla, F. [SourceLAB SAS, 86 Rue de Paris, 91400 Orsay (France); Lambert, G. [LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Gizzi, L. A. [Intense Laser Irradiation Laboratory (ILIL), Istituto Nazionale di Ottica (INO-CNR), Via Moruzzi 1, 56124 Pisa (Italy)

2016-08-15

The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10{sup 19} cm{sup −3} range well suited for LWFA.

Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

Science.gov (United States)

Brandi, F.; Giammanco, F.; Conti, F.; Sylla, F.; Lambert, G.; Gizzi, L. A.

2016-08-01

The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 1019 cm-3 range well suited for LWFA.

Shock-wave proton acceleration from a hydrogen gas jet

Science.gov (United States)

Cook, Nathan; Pogorelsky, Igor; Polyanskiy, Mikhail; Babzien, Marcus; Tresca, Olivier; Maharjan, Chakra; Shkolnikov, Peter; Yakimenko, Vitaly

2013-04-01

Typical laser acceleration experiments probe the interaction of intense linearly-polarized solid state laser pulses with dense metal targets. This interaction generates strong electric fields via Transverse Normal Sheath Acceleration and can accelerate protons to high peak energies but with a large thermal spectrum. Recently, the advancement of high pressure amplified CO2 laser technology has allowed for the creation of intense (10^16 Wcm^2) pulses at λ˜10 μm. These pulses may interact with reproducible, high rep. rate gas jet targets and still produce plasmas of critical density (nc˜10^19 cm-3), leading to the transference of laser energy via radiation pressure. This acceleration mode has the advantage of producing narrow energy spectra while scaling well with pulse intensity. We observe the interaction of an intense CO2 laser pulse with an overdense hydrogen gas jet. Using two pulse optical probing in conjunction with interferometry, we are able to obtain density profiles of the plasma. Proton energy spectra are obtained using a magnetic spectrometer and scintillating screen.

Computer simulations of a single-laser double-gas-jet wakefield accelerator concept

Directory of Open Access Journals (Sweden)

R. G. Hemker

2002-04-01

Full Text Available We report in this paper on full scale 2D particle-in-cell simulations investigating laser wakefield acceleration. First we describe our findings of electron beam generation by a laser propagating through a single gas jet. Using realistic parameters which are relevant for the experimental setup in our laboratory we find that the electron beam resulting after the propagation of a 0.8 μm, 50 fs laser through a 1.5 mm gas jet has properties that would make it useful for further acceleration. Our simulations show that the electron beam is generated when the laser exits the gas jet, and the properties of the generated beam, especially its energy, depend only weakly on most properties of the gas jet. We therefore propose to use the first gas jet as a plasma cathode and then use a second gas jet placed immediately behind the first to provide additional acceleration. Our simulations of this proposed setup indicate the feasibility of this idea and also suggest ways to optimize the quality of the resulting beam.

Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers

International Nuclear Information System (INIS)

Estellano, Victor H.; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

2015-01-01

Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3–5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC–MS. The organophosphates insecticides; chlorpyrifos (3–580 pg m −3 ) and chlorpyrifos-methyl (below detection limit – to 570 pg m −3 ) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk. - Highlights: • Current use pesticides (CUPs) were detected in the atmosphere of Tuscany, Italy. • Chlorpyrifos showed the highest concentrations in air with seasonal patterns. • CUPs levels might be influenced by agricultural activities. • No differences were detected between Urban and Rural sites. • Air mass analysis indicated the monitoring sites are influenced by local sources. - Seasonality of CUPs was measured in Tuscany, Italy. Chlorpyrifos showed the highest values. Urban and rural sites showed no differences. Agricultural activities influence CUPs levels in air

Influence of Puffing Parameters and Filter Vent Blocking Condition on Nicotine Fate in a Burning Cigarette - Part 1. Full Flavor Cigarettes

Directory of Open Access Journals (Sweden)

Yu J

2014-12-01

Full Text Available Cigarette testing regulations based on more intensive puffing conditions than standard Federal Trade Commission/International Organisation for Standardization (FTC/ISO conditions, together with intentional filter vent-blocking of cigarettes during testing, are currently required in some countries. Recently, an initial recommendation under the auspices of the Framework Convention on Tobacco Control, has called for international machine-testing of cigarettes with a 55 cc/30 s/2 s puffing regimen after 100% filter vent-blocking. While much is currently known regarding changes in smoke yields with different machine smoking parameters, a more limited understanding of potential changes in smoke composition exists. In the present work, the influence of smoking conditions on nicotine fate in a burning cigarette was studied by gas chromatography with atomic emission detection (GC-AED using core-injected nicotine-d4. Tobacco rods were injected via a syringe to a fixed length with a constant volume of a methanol solution of known concentration of deuterated nicotine. Four different puffing conditions and two different vent-blocking conditions were studied. GC with mass spectrometric detection was used to identify the deuterium-labeled compounds that gave an enhanced deuterium AED-response. A comparison of the distribution of compounds containing deuterium in the mainstream smoke, sidestream smoke, and cigarette remains (butt and ash of a full flavor cigarette brand under the four smoking conditions studied indicated that a greater percentage of labeled nicotine remained intact during the smoking process as the intensity of the puffing regimen increased. As smoking regimen intensity increased, the amounts of nicotine pyrolysis and oxidation products detected in sidestream smoke decreased, while marginal increases in these compounds were observed in mainstream smoke and in the cigarette butt. The sidestream/mainstream nicotine ratio decreased significantly

Energy transfer dynamics in an RC-LH1-PufX tubular photosynthetic membrane

International Nuclear Information System (INIS)

Hsin, J; Sener, M; Schulten, K; Struempfer, J; Qian, P; Hunter, C N

2010-01-01

Light absorption and the subsequent transfer of excitation energy are the first two steps in the photosynthetic process, carried out by protein-bound pigments, mainly bacteriochlorophylls (BChls), in photosynthetic bacteria. BChls are anchored in light-harvesting (LH) complexes, such as light-harvesting complex I (LH1), which directly associates with the reaction center (RC), forming the RC-LH1 core complex. In Rhodobacter sphaeroides, RC-LH1 core complexes contain an additional protein, PufX, and assemble into dimeric RC-LH1-PufX core complexes. In the absence of LH complex II (LH2), the former complexes can aggregate into a helically ordered tubular photosynthetic membrane. We have examined the excitation transfer dynamics in a single RC-LH1-PufX core complex dimer using the hierarchical equations of motion for dissipative quantum dynamics that accurately, yet in a computationally costly manner, treat the coupling between BChls and their protein environment. A widely employed description, the generalized Foerster (GF) theory, was also used to calculate the transfer rates of the same excitonic system in order to verify the accuracy of this computationally cheap method. Additionally, in light of the structural uncertainties in the Rba. sphaeroides RC-LH1-PufX core complex, geometrical alterations were introduced into the BChl organization. It is shown that the energy transfer dynamics are not affected by the considered changes in the BChl organization and that the GF theory provides accurate transfer rates. An all-atom model for a tubular photosynthetic membrane is then constructed on the basis of electron microscopy data, and the overall energy transfer properties of this membrane are computed.

Energy transfer dynamics in an RC-LH1-PufX tubular photosynthetic membrane

Energy Technology Data Exchange (ETDEWEB)

Hsin, J; Sener, M; Schulten, K [Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana (United States); Struempfer, J [Center for Biophysics and Computational Biology and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana (United States); Qian, P; Hunter, C N, E-mail: kschulte@ks.uiuc.ed [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom)

2010-08-15

Light absorption and the subsequent transfer of excitation energy are the first two steps in the photosynthetic process, carried out by protein-bound pigments, mainly bacteriochlorophylls (BChls), in photosynthetic bacteria. BChls are anchored in light-harvesting (LH) complexes, such as light-harvesting complex I (LH1), which directly associates with the reaction center (RC), forming the RC-LH1 core complex. In Rhodobacter sphaeroides, RC-LH1 core complexes contain an additional protein, PufX, and assemble into dimeric RC-LH1-PufX core complexes. In the absence of LH complex II (LH2), the former complexes can aggregate into a helically ordered tubular photosynthetic membrane. We have examined the excitation transfer dynamics in a single RC-LH1-PufX core complex dimer using the hierarchical equations of motion for dissipative quantum dynamics that accurately, yet in a computationally costly manner, treat the coupling between BChls and their protein environment. A widely employed description, the generalized Foerster (GF) theory, was also used to calculate the transfer rates of the same excitonic system in order to verify the accuracy of this computationally cheap method. Additionally, in light of the structural uncertainties in the Rba. sphaeroides RC-LH1-PufX core complex, geometrical alterations were introduced into the BChl organization. It is shown that the energy transfer dynamics are not affected by the considered changes in the BChl organization and that the GF theory provides accurate transfer rates. An all-atom model for a tubular photosynthetic membrane is then constructed on the basis of electron microscopy data, and the overall energy transfer properties of this membrane are computed.

Experimental study on gas-puff Z-pinch load characteristics on yang accelerator

International Nuclear Information System (INIS)

Ren Xiaodong; Huang Xianbin; Yang Libing; Dan Jiakun; Duan Shuchao; Zhang Zhaohui; Zhou Shaotong

2010-01-01

A supersonic single-shell gas-puff load has been developed for Z-pinch experiments on 'Yang' accelerator. Using a fast responding pressure probe to measure the supersonic gas flow, impact pressure at different position and plenum pressure were acquired, which were combined with gas dynamics formulas to determine gas pressures and densities. The radial density profile displays that positions of gas shell varies with axial position, and the gas densities on axis increases as the distance from nozzle increases. Integral radial densities indicates that the linear mass density peaks at nozzle exit and decreases as increasing the distance from nozzle. Using single-shell supersonic gas-puff load, Z-pinch implosion experiments were performed on 'Yang' accelerator. Primary analysis of implosion process was presented, and computational trajectories of imploding plasma shell using snowplow model are in agreement with the experimental results. (authors)

Investigation of pellet acceleration by an arc heated gas gun

International Nuclear Information System (INIS)

Andersen, S.A.; Baekmark, L.; Jensen, V.O.; Michelsen, P.; Weisberg, K.V.

1988-10-01

This report describes work on pellet acceleration by means of an arc heated gas gun. Preliminary results were described in Riso-M-2536 and in Riso-M-2650. This final report describes the work carried out from 1987.03.31 to 1988.09.30. An arc heated hydrogen gas source, for pneumatic acceleration of deuterium pellets to velocities above 2 km/s, was developed. Experiments were performed with an arc chamber to which different methods of hydrogen supply were possible, and to which the input of electrical power could be programmed. Results in terms of pressure transients and acceleration curves are presented. Maximum pellet velocities approaching 2 km/s were obtained. This limit is discussed in relation to the presented data. Finally this report contains a summary and a conclusion for the entire project. (author) 34 ills., 3 refs

FK Comae Berenices, King of Spin: The COCOA-PUFS Project

Science.gov (United States)

Ayres, Thomas R.; Kashyap, V.; Saar, S.; Huenemoerder, D.; Korhonen, H.; Drake, J. J.; Testa, P.; Cohen, O.; Garraffo, C.; Granzer, T.; Strassmeier, K.

2016-03-01

COCOA-PUFS is an energy-diverse, time-domain study of the ultra-fast spinning, heavily spotted, yellow giant FK Comae Berenices (FK Com: HD117555; G4 III). This single star is thought to be a recent binary merger, and is exceptionally active by measure of its intense ultraviolet (UV) and X-ray emissions, and proclivity to flare. COCOA-PUFS was carried out with the Hubble Space Telescope in the UV (1200-3000 Å), using mainly its high-performance Cosmic Origins Spectrograph, but also high precision Space Telescope Imaging Spectrograph; Chandra X-ray Observatory in the soft X-rays (0.5-10 keV), utilizing its High-Energy Transmission Grating Spectrometer; together with supporting photometry and spectropolarimetry in the visible from the ground. This is an introductory report on the project. FK Com displayed variability on a wide range of timescales over all wavelengths during the week-long main campaign, including a large X-ray flare; “super-rotational broadening” of the far-ultraviolet “hot lines” (e.g., Si IV 1393 Å 8 × 104 K) together with chromospheric Mg II 2800 Å and C II 1335 Å (1-3 × 104 K); large Doppler swings suggestive of bright regions alternately on advancing and retreating limbs of the star; and substantial redshifts of the epoch-average emission profiles. These behaviors paint a picture of a highly extended, dynamic, hot (˜10 MK) coronal magnetosphere around the star, threaded by cooler structures perhaps analogous to solar prominences and replenished continually by surface activity and flares. Suppression of angular momentum loss by the confining magnetosphere could temporarily postpone the inevitable stellar spindown, thereby lengthening this highly volatile stage of coronal evolution. COordinated Campaign of Observations and Analysis, Photosphere to Upper Atmosphere, of a Fast-rotating Star.

FK COMAE BERENICES, KING OF SPIN: THE COCOA-PUFS PROJECT

Energy Technology Data Exchange (ETDEWEB)

Ayres, Thomas R. [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); Kashyap, V.; Saar, S.; Drake, J. J.; Testa, P.; Cohen, O.; Garraffo, C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Huenemoerder, D. [Massachusetts Institute of Technology, Cambridge, MA (United States); Korhonen, H. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Granzer, T.; Strassmeier, K., E-mail: Thomas.Ayres@Colorado.edu [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

2016-03-15

COCOA-PUFS is an energy-diverse, time-domain study of the ultra-fast spinning, heavily spotted, yellow giant FK Comae Berenices (FK Com: HD117555; G4 III). This single star is thought to be a recent binary merger, and is exceptionally active by measure of its intense ultraviolet (UV) and X-ray emissions, and proclivity to flare. COCOA-PUFS was carried out with the Hubble Space Telescope in the UV (1200–3000 Å), using mainly its high-performance Cosmic Origins Spectrograph, but also high precision Space Telescope Imaging Spectrograph; Chandra X-ray Observatory in the soft X-rays (0.5–10 keV), utilizing its High-Energy Transmission Grating Spectrometer; together with supporting photometry and spectropolarimetry in the visible from the ground. This is an introductory report on the project. FK Com displayed variability on a wide range of timescales over all wavelengths during the week-long main campaign, including a large X-ray flare; “super-rotational broadening” of the far-ultraviolet “hot lines” (e.g., Si iv 1393 Å; 8 × 10{sup 4} K) together with chromospheric Mg ii 2800 Å and C ii 1335 Å (1–3 × 10{sup 4} K); large Doppler swings suggestive of bright regions alternately on advancing and retreating limbs of the star; and substantial redshifts of the epoch-average emission profiles. These behaviors paint a picture of a highly extended, dynamic, hot (∼10 MK) coronal magnetosphere around the star, threaded by cooler structures perhaps analogous to solar prominences and replenished continually by surface activity and flares. Suppression of angular momentum loss by the confining magnetosphere could temporarily postpone the inevitable stellar spindown, thereby lengthening this highly volatile stage of coronal evolution.

FK COMAE BERENICES, KING OF SPIN: THE COCOA-PUFS PROJECT

International Nuclear Information System (INIS)

Ayres, Thomas R.; Kashyap, V.; Saar, S.; Drake, J. J.; Testa, P.; Cohen, O.; Garraffo, C.; Huenemoerder, D.; Korhonen, H.; Granzer, T.; Strassmeier, K.

2016-01-01

COCOA-PUFS is an energy-diverse, time-domain study of the ultra-fast spinning, heavily spotted, yellow giant FK Comae Berenices (FK Com: HD117555; G4 III). This single star is thought to be a recent binary merger, and is exceptionally active by measure of its intense ultraviolet (UV) and X-ray emissions, and proclivity to flare. COCOA-PUFS was carried out with the Hubble Space Telescope in the UV (1200–3000 Å), using mainly its high-performance Cosmic Origins Spectrograph, but also high precision Space Telescope Imaging Spectrograph; Chandra X-ray Observatory in the soft X-rays (0.5–10 keV), utilizing its High-Energy Transmission Grating Spectrometer; together with supporting photometry and spectropolarimetry in the visible from the ground. This is an introductory report on the project. FK Com displayed variability on a wide range of timescales over all wavelengths during the week-long main campaign, including a large X-ray flare; “super-rotational broadening” of the far-ultraviolet “hot lines” (e.g., Si iv 1393 Å; 8 × 10 4 K) together with chromospheric Mg ii 2800 Å and C ii 1335 Å (1–3 × 10 4 K); large Doppler swings suggestive of bright regions alternately on advancing and retreating limbs of the star; and substantial redshifts of the epoch-average emission profiles. These behaviors paint a picture of a highly extended, dynamic, hot (∼10 MK) coronal magnetosphere around the star, threaded by cooler structures perhaps analogous to solar prominences and replenished continually by surface activity and flares. Suppression of angular momentum loss by the confining magnetosphere could temporarily postpone the inevitable stellar spindown, thereby lengthening this highly volatile stage of coronal evolution

Preformed transient gas channels for laser wakefield particle acceleration

International Nuclear Information System (INIS)

Wood, W.M.

1994-01-01

Acceleration of electrons by laser-driven plasma wake fields is limited by the range over which a laser pulse can maintain its intensity. This distance is typically given by the Rayleigh range for the focused laser beam, usually on the order of 0.1 mm to 1 mm. For practical particle acceleration, interaction distances on the order of centimeters are required. Therefore, some means of guiding high intensity laser pulses is necessary. Light intensities on the order of a few times 10 17 W/cm 2 are required for laser wakefield acceleration schemes using near IR radiation. Gas densities on the order of or greater than 10 17 cm -3 are also needed. Laser-atom interaction studies in this density and intensity regime are generally limited by the concomitant problems in beam propagation introduced by the creation of a plasma. In addition to the interaction distance limit imposed by the Rayleigh range, defocusing of the high intensity laser pulse further limits the peak intensity which can be achieved. To solve the problem of beam propagation limitations in laser-plasma wakefield experiments, two potential methods for creating transient propagation channels in gaseous targets are investigated. The first involves creation of a charge-neutral channel in a gas by an initial laser pulse, which then is ionized by a second, ultrashort, high-intensity pulse to create a waveguide. The second method involves the ionization of a gas column by an ultrashort pulse; a transient waveguide is formed by the subsequent expansion of the heated plasma into the neutral gas

Investigation of physico-chemical processes in hypervelocity MHD-gas acceleration wind tunnels

International Nuclear Information System (INIS)

Alfyorov, V.I.; Dmitriev, L.M.; Yegorov, B.V.; Markachev, Yu.E.

1995-01-01

The calculation results for nonequilibrium physicochemical processes in the circuit of the hypersonic MHD-gas acceleration wind tunnel are presented. The flow in the primary nozzle is shown to be in thermodynamic equilibrium at To=3400 K, Po=(2∼3)x10 5 Pa, M=2 used in the plenum chamber. Variations in the static pressure due to oxidation reaction of Na, K are pointed out. The channels of energy transfer from the electric field to different degrees of freedom of an accelerated gas with Na, K seeds are considered. The calculation procedure for gas dynamic and kinetic processes in the MHD-channel using measured parameters is suggested. The calculated results are compared with the data obtained in a thermodynamic gas equilibrium assumption. The flow in the secondary nozzle is calculated under the same assumptions and the gas parameters at its exit are evaluated. Particular attention is given to the influence of seeds on flows over bodies. It is shown that the seeds exert a very small influence on the flow behind a normal shock wave. The seeds behind an oblique shock wave accelerate deactivation of vibrations of N 2 , but this effect is insignificant

Investigation of advanced propulsion technologies: The RAM accelerator and the flowing gas radiation heater

Science.gov (United States)

Bruckner, A. P.; Knowlen, C.; Mattick, A. T.; Hertzberg, A.

1992-01-01

The two principal areas of advanced propulsion investigated are the ram accelerator and the flowing gas radiation heater. The concept of the ram accelerator is presented as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerothermodynamics research. The ram accelerator is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled in a stationary tube filled with a tailored combustible gas mixture. Combustion on and behind the projectile generates thrust which accelerates it to very high velocities. The acceleration can be tailored for the 'soft launch' of instrumented models. The distinctive reacting flow phenomena that have been observed in the ram accelerator are relevant to the aerothermodynamic processes in airbreathing hypersonic propulsion systems and are useful for validating sophisticated CFD codes. The recently demonstrated scalability of the device and the ability to control the rate of acceleration offer unique opportunities for the use of the ram accelerator as a large-scale hypersonic ground test facility. The flowing gas radiation receiver is a novel concept for using solar energy to heat a working fluid for space power or propulsion. Focused solar radiation is absorbed directly in a working gas, rather than by heat transfer through a solid surface. Previous theoretical analysis had demonstrated that radiation trapping reduces energy loss compared to that of blackbody receivers, and enables higher efficiencies and higher peak temperatures. An experiment was carried out to measure the temperature profile of an infrared-active gas and demonstrate the effect of radiation trapping. The success of this effort validates analytical models of heat transfer in this receiver, and confirms the potential of this approach for achieving high efficiency space power and propulsion.

Generation of auroral kilometric radiation and the structure of auroral acceleration region

International Nuclear Information System (INIS)

Lee, L.C.; Kan, J.R.; Wu, C.S.

1980-01-01

Generation of auroral kilometric radiation (AKR) in the auroral acceleration region is studied. It is shown that auroral kilometric radiation can be generated by the backscattered electrons trapped in the acceleration region via a cyclotron maser process. The parallel electric field in the acceleration region is required to be distributed over 1-2 Rsub(E). The observed AKR frequency spectrum can be used to estimate the altitude range of the auroral acceleration region. The altitudes of the lower and upper boundaries of the acceleration region determined from the AKR data are respectively approximately 2000 and approximately 9000 km. (author)

E-cigarette puffing patterns associated with high and low nicotine e-liquid strength: effects on toxicant and carcinogen exposure.

Science.gov (United States)

Cox, Sharon; Kośmider, Leon; McRobbie, Hayden; Goniewicz, Maciej; Kimber, Catherine; Doig, Mira; Dawkins, Lynne

2016-09-20

Contrary to intuition, use of lower strength nicotine e-liquids might not offer reduced health risk if compensatory puffing behaviour occurs. Compensatory puffing (e.g. more frequent, longer puffs) or user behaviour (increasing the wattage) can lead to higher temperatures at which glycerine and propylene glycol (solvents used in e-liquids) undergo decomposition to carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. This study aims to document puffing patterns and user behaviour associated with using high and low strength nicotine e-liquid and associated toxicant/carcinogen exposure in experienced e-cigarette users (known as vapers herein). A counterbalanced repeated measures design. Non-tobacco smoking vapers; have used an e-cigarette for ≥3 months; currently using nicotine strength e-liquid ≥12mg/mL and a second or third generation device. This study will measure puffing patterns in vapers whilst they use high and low strength nicotine e-liquid under fixed and user-defined settings, each for a week. The 4 counterbalanced conditions are: i) low strength (6mg/mL), fixed settings; ii) low strength user-defined settings; iii) high strength (18mg/mL) fixed settings; iv) high strength user-defined settings. Biomarkers of exposure to toxicants and carcinogens will be measured in urine. In the second phase of this study, toxicant yields will be measured in aerosol generated using a smoking machine operated to replicate the puffing behaviours of each participant. i) Puffing patterns (mean puff number, puff duration, inter-puff interval and mL of liquid consumed) and user behaviour (changes to device settings: voltage and air-flow) associated with using high and low strength nicotine e-liquid. ii) Toxicant/carcinogen exposure associated with the puffing patterns/device settings used by our participants. i) Subjective effects. ii) comparisons with toxicant exposure from tobacco smoke (using documented evidence) and with recommended safety limits

E-cigarette puffing patterns associated with high and low nicotine e-liquid strength: effects on toxicant and carcinogen exposure

Directory of Open Access Journals (Sweden)

Sharon Cox

2016-09-01

Full Text Available Abstract Background Contrary to intuition, use of lower strength nicotine e-liquids might not offer reduced health risk if compensatory puffing behaviour occurs. Compensatory puffing (e.g. more frequent, longer puffs or user behaviour (increasing the wattage can lead to higher temperatures at which glycerine and propylene glycol (solvents used in e-liquids undergo decomposition to carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. This study aims to document puffing patterns and user behaviour associated with using high and low strength nicotine e-liquid and associated toxicant/carcinogen exposure in experienced e-cigarette users (known as vapers herein. Methods/design A counterbalanced repeated measures design. Participants: Non-tobacco smoking vapers; have used an e-cigarette for ≥3 months; currently using nicotine strength e-liquid ≥12mg/mL and a second or third generation device. Intervention: This study will measure puffing patterns in vapers whilst they use high and low strength nicotine e-liquid under fixed and user-defined settings, each for a week. The 4 counterbalanced conditions are: i low strength (6mg/mL, fixed settings; ii low strength user-defined settings; iii high strength (18mg/mL fixed settings; iv high strength user-defined settings. Biomarkers of exposure to toxicants and carcinogens will be measured in urine. In the second phase of this study, toxicant yields will be measured in aerosol generated using a smoking machine operated to replicate the puffing behaviours of each participant. Primary outcomes: i Puffing patterns (mean puff number, puff duration, inter-puff interval and mL of liquid consumed and user behaviour (changes to device settings: voltage and air-flow associated with using high and low strength nicotine e-liquid. ii Toxicant/carcinogen exposure associated with the puffing patterns/device settings used by our participants. Secondary outcomes: i Subjective effects. ii comparisons

Dietary exposure to aluminium from wheat flour and puffed products of residents in Shanghai, China.

Science.gov (United States)

Guo, Junfei; Peng, Shaojie; Tian, Mingsheng; Wang, Liwei; Chen, Bo; Wu, Min; He, Gengsheng

2015-01-01

A dietary survey of 3431 residents was conducted by a 24-h dietary recall method in Shanghai, China, quarterly from September 2013 to September 2014. A total of 400 food samples were tested for aluminium concentration, including wheat flour and puffed products from 2011 to 2013. Probabilistic analysis was used to estimate the dietary exposure to aluminium from wheat and puffed products. The means of dietary aluminium exposure for children (2-6 years old), juveniles (7-17 years old), adults (18-65 years old) and seniors (over 65 years old) were 1.88, 0.94, 0.44 and 0.42 mg kg(-1) body weight (bw) week(-1) respectively, with a population average of 0.51 mg kg(-1) bw week(-1). The proportions of those who had aluminium exposure from wheat and puffed products lower than the provisional tolerable weekly intake (PTWI) were 77%, 90%, 97%, and 97% respectively from children to seniors. We estimated that the proportions of people at risk would decrease by 13%, 6%, 2% and 2% respectively under the new China National Standards - GB 2760-2014 National Food Safety for Standards for using food additives. The results indicated that aluminium from wheat flour and puffed products is unlikely to cause adverse health effects in the general population in Shanghai; however, children were at a higher risk of excess aluminium exposure. Significant improvements in reducing the dietary exposure to aluminium are expected in the population, especially for children after the implementation of GB 2760-2014.

Modification in existing SF6 gas handling system at 14UD BARC-TIFR Pelletron Accelerator, Mumbai

International Nuclear Information System (INIS)

Ninawe, N.G.; Gupta, S.K.; Ramjilal; Sparrow, Hillary; Sharma, S.C.; Bhagwat, P.V.; Salvi, S.B.

2003-01-01

BARC-TIFR 14 UD Pelletron Accelerator facility at TIFR, Mumbai is operational since inception 1989. The accelerator is housed inside a pressure vessel of 6 metre diameter, 25 metre long and 525m 3 volume. The accelerator tank is pressurized with SF 6 at 80 to 100 psig in order to achieve 14MV. The inventory of SF 6 gas is about 18,000 Kg (approximately) at 80 psig. SF 6 gas can be transported from Accelerator tank to storage tank using gas handling system, which consists of oil free compressor, vacuum pump, dust filters, oil filters, dryers etc

Effect of apple varieties and irradiation on the quality of explosion puffed apple slices

International Nuclear Information System (INIS)

Bi Jinfeng; Ding Yuanyuan; Wang Pei; Bai Shasha

2009-01-01

Many factors affect the quality of explosion puffed apple slices. Apple varieties of Guoguang, Fuji, Hongxiangjiao and Huangxiangjiao were used as materal, the quality of fresh apple and explosion puffed products were analyzed based on the data of their physical and chemical characteristics and flavor. The results showed that Guoguang apple had the optimal flavor and Huangxiangjiao apple had the optimal product quality. So the Guoguang apple was selected as the material for the following results showed that irradiation could soften apple tissue, improve the pre-drying rate, increase products crispness, and also reduce the products hardness, but the irradiation of 2 and 5 kGy could turn products brown seriously, which reduced the product quality. (authors)

Current-voltage relationship in the auroral particle acceleration region

Directory of Open Access Journals (Sweden)

M. Morooka

2004-11-01

Full Text Available The current-voltage relationship in the auroral particle acceleration region has been studied statistically by the Akebono (EXOS-D satellite in terms of the charge carriers of the upward field-aligned current. The Akebono satellite often observed field-aligned currents which were significantly larger than the model value predicted by Knight (1973. We compared the upward field-aligned current estimated by three different methods, and found that low-energy electrons often play an important role as additional current carriers, together with the high-energy primary electrons which are expected from Knight's relation. Such additional currents have been observed especially at high and middle altitudes of the particle acceleration region. Some particular features of electron distribution functions, such as "cylindrical distribution functions" and "electron conics", have often been observed coinciding with the additional currents. They indicated time variability of the particle acceleration region. Therefore, we have concluded that the low-energy electrons within the "forbidden" region of electron phase space in the stationary model often contribute to charge carriers of the current because of the rapid time variability of the particle acceleration region. "Cylindrical distribution functions" are expected to be found below the time-varying potential difference. We statistically examined the locations of "cylindrical distribution function", and found that their altitudes are related to the location where the additional currents have been observed. This result is consistent with the idea that the low-energy electrons can also carry significant current when the acceleration region changes in time.

Diversity of pufM genes, involved in aerobic anoxygenic photosynthesis, in the bacterial communities associated with colonial ascidians.

Science.gov (United States)

Martínez-García, Manuel; Díaz-Valdés, Marta; Antón, Josefa

2010-03-01

Ascidians are invertebrate filter feeders widely distributed in benthic marine environments. A total of 14 different ascidian species were collected from the Western Mediterranean and their bacterial communities were analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene. Results showed that ascidian tissues harbored Bacteria belonging to Gamma- and Alphaproteobacteria classes, some of them phylogenetically related to known aerobic anoxygenic phototrophs (AAPs), such as Roseobacter sp. In addition, hierarchical cluster analysis of DGGE patterns showed a large variability in the bacterial diversity among the different ascidians analyzed, which indicates that they would harbor different bacterial communities. Furthermore, pufM genes, involved in aerobic anoxygenic photosynthesis in marine and freshwater systems, were widely detected within the ascidians analyzed, because nine out of 14 species had pufM genes inside their tissues. The pufM gene was only detected in those specimens that inhabited shallow waters (<77 m of depth). Most pufM gene sequences were very closely related to that of uncultured marine bacteria. Thus, our results suggest that the association of ascidians with bacteria related to AAPs could be a general phenomenon and that ascidian-associated microbiota could use the light that penetrates through the tunic tissue as an energy source.

Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

Science.gov (United States)

Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

2018-01-01

Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active air sampler and determined the corresponding uptake rates (Rs). These rates were then used to estimate the occupational exposure of firefighters and police forensic specialists to 32 PAHs. The work environments studied were heavily contaminated by PAHs with (for example) benzo(a)pyrene ranging from 0.2 to 56 ng m -3 , as measured via active sampling. We show that, even after short exposure times, PUF can reliably accumulate both gaseous and particle-bound PAHs. The Rs-values are almost independent of variables such as the concentration and the wind speed. Therefore, by using the Rs-values (2.0-20 m 3 day -1 ), the air concentrations can be estimated within a factor of two for gaseous PAHs and a factor of 10 for particulate PAHs. With very short sampling times (1 h), our method can serve as a (i) simple and user-friendly semi-quantitative screening tool for estimating and tracking point sources of PAH in micro-environments and (ii) complement to the traditional active pumping methods. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Field calibration of polyurethane foam (PUF) disk passive air samplers for PCBs and OC pesticides.

Science.gov (United States)

Chaemfa, Chakra; Barber, Jonathan L; Gocht, Tilman; Harner, Tom; Holoubek, Ivan; Klanova, Jana; Jones, Kevin C

2008-12-01

Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.

Structural model and excitonic properties of the dimeric RC-LH1-PufX complex from Rhodobacter sphaeroides

International Nuclear Information System (INIS)

Sener, Melih; Hsin, Jen; Trabuco, Leonardo G.; Villa, Elizabeth; Qian, Pu; Hunter, C. Neil; Schulten, Klaus

2009-01-01

The light-harvesting apparatus of the purple bacterial photosynthetic unit consists of a pool of peripheral light-harvesting complexes that transfer excitation energy to a reaction center (RC) via the surrounding pigment-protein complex LH1. Recent electron microscopy and atomic force microscopy studies have revealed that RC-LH1 units of Rhodobacter (Rba.) sphaeroides form membrane-bending dimeric complexes together with the polypeptide PufX. We present a structural model for these RC-LH1-PufX dimeric complexes constructed using the molecular dynamics flexible fitting method based on an EM density map. The arrangement of the LH1 BChls displays a distortion near the proposed location of the PufX polypeptide. The resulting atomic model for BChl arrays is used to compute the excitonic properties of the dimeric RC-LH1 complex. A comparison is presented between the structural and excitonic features of the S-shaped dimeric BChl array of Rba. sphaeroides and the circular BChl arrangement found in other purple bacteria

Study of regional pulmonary gas exchange using radiotracers

International Nuclear Information System (INIS)

Hichwa, R.D.

1981-01-01

Respiration involves the exchange of gases between the environment and the blood across the alveolar membrane. Four processes characterize the dynamics of gas exchange: ventilation, diffusion, perfusion and chemical binding with hemoglobin. A study was undertaken to investigate each of these processes, utilizing accelerator production and high yield synthesis of four gaseous radiotracers (/sup 81m/Kr, Ch 3 18 F, 11 CO, 15 O 2 ). Conventional gamma camera images and ancillary physiological data were acquired. Mathematical models were developed to predict the tracer clearance from the lungs during a breath hold and during washout post breath hold. Images of the insoluble /sup 81m/Kr synchronized with the tidal breathing maneuver depict regional ventilation. Tracer bolus inhalation, relative compliance and regional phase information are obtained from krypton dCynamic studies. More soluble CH 3 18 F is used to determine regional pulmonary perfusion during a breath hold. Respiratory clearance of seven, inert, positron-emitting radiotracers define the tracer volume of distribution. The tight-binding of 11 CO to hemoglobin permits the regional measurement of carbon monoxide pulmonary diffusion capacity. A relative CO blood:gas partition coefficient is calculated from the washout of no-carrier-added levels of 11 CO and verified by in vitro radiometric measurements. Regional oxygen pulmonary diffusion capacity determined from 15 O 2 clearance during a breath hold reveals results similar to those obtained with CO. All experimental data are in good agreement with the predictions of a two-compartment open model. A more advanced oxygen model is presented that incorporates radioactive oxygen exchange with stable oxygen on the hemoglobin molecule and metabolic removal of the tracer at the tissues

Electrostatic accelerator dielectrics

International Nuclear Information System (INIS)

Cooke, C.M.

1989-05-01

High voltage insulation problems in electrostatic accelerators are discussed. The aim of the analysis is to broaden the knowledge, highlight the characteristics of insulation technology and design strategies to improve use. The basic geometry of the insulation in accelerators is considered. A detailed description of each of the insulation regions is provided. The gas gap insulation of the terminal voltage is found to be sensitive to regions of high electric stress. In order to obtain satisfactory performance from solid support insulation, the attention is focused on the electric stress value and distribution. Potential subjects for discussion and further investigations are given

Seismic acceleration map expected for Japanese central region

International Nuclear Information System (INIS)

Sugiyama, Takeshi; Maeda, Kouji; Ishii, Kiyoshi; Suzuki, Makoto.

1990-01-01

Since electric generating and supplying facilities scatter in large areas, the seismic acceleration map, which defines the anticipated earthquake ground motions in a broad region, is very useful information for the design of those facilities against large earthquakes. This paper describes the development of a seismic acceleration map for the Central Japanese Region by incorporating the analytical results based on historical earthquake records and active fault data using probability and statistics. In the region, there have occurred several destructive earthquakes; Anseitokai (1854, M = 8.4) and Tohnankai (1944, M = 7.9) earthquakes along the Nankai trough; Nohbi (1891, M = 8.0) and Fukui (1948, M = 7.1) earthquakes in inland ares. Some of the historical earthquake data were obtained by instrument last one hundred years, whereas others by literary descriptions for nearly 1,000 years. The active fault data, have been collected mainly from the surveys of fault topography and geology, and are considered to indicate the average seismic activity for the past million years. A proposed seismic acceleration map for the return period of 75 years, calculated on the free surface of base stratum, was estimated by the following way. The analytical result based on the historical earthquake records was adopted mainly, because the Japanese seismic design criteria have been developed based on them. The proposed seismic acceleration map was revised by including the result based on the active fault data for the areas, where historical earthquake records lack, and the result was smoothed to evaluate the final seismic acceleration map. (author)

The design of the extraction window of high power electron accelerator used in flue gas desulfurization

International Nuclear Information System (INIS)

He Tongqi; Chinese Academy of Sciences, Shanghai; Hu Wei; Sun Guangkui; Shi Weiguo; Li Minxi; Zhang Yutian; Pu Gengqiang

2007-01-01

Recently, the pollution caused by industrial exhaust gas, especially, the air pollution and acid rain resulting from the sulfur of exhaust gas, is increasingly drawing people's attention. The flue gas desulfurization by electron beam produced by high-power electron accelerator has the characteristics of high efficiency and non-secondary contamination. As one of the most pivotal part of accelerator, the service lifetime of this extraction window directly effects the stable operation of the device. In this paper, a brief review is given to summarize the advantages, material selecting, structure, replacing, maintaining of the extraction window of high-power electron accelerator developed by SINAP. (authors)

Confinement and gas fueling in LHD limiter discharges

International Nuclear Information System (INIS)

Nishimura, K.; Kawahata, K.; Narihara, K.; Morisaki, T.; Masuzaki, S.; Sakakibara, S.; Tanaka, K.

2003-01-01

Plasma discharges in the Large Helical Device are normally open helical divertor discharges. To compare limiter discharges with open divertor discharges and to examine the role of the peripheral region, a radial movable limiter, whose head was made of carbon with high heat conductivity, was inserted into the plasma from the high field side (near the helical coil). The electron temperature was bounded well by the limiter. A high temperature gradient at the edge region was observed in both open divertor and limiter discharges. Formation of such a high temperature gradient led to good energy confinement even in the limiter discharges and an enhancement factor of 1.1±0.3 for International Stellarator Scaling 95 (ISS95) scaling was observed at every limiter position (0.75 ax =3.75 m prevents gas fueling by puffing

Leak detection of SF6 gas pressure vessel safety devices at BARC-TIFR Pelletron accelerator

International Nuclear Information System (INIS)

Ninawe, N.G.; Sharma, S.C.; Nair, J.P.; Sparrow, H.; Bolar, P.C.; Gudekar, P.V.; Mahapatra, S.; Vishwakarma, R.S.; Ramjilal; Matkar, U.V.; Gore, J.A.; Gupta, A.K.

2015-01-01

Pelletron accelerator is in operation since last more than 26 years. To achieve desired voltage gradient SF6 gas of about 20 tons is used to have 75-80 psig pressure in main accelerator tank. During accelerator tank maintenance gas is transferred to four storage tanks, kept in open space in the vicinity of sea. Recently refurbishment and retrofitting of four storage tanks was carried out which includes the installation of new drift space, rupture disc assembly, relief valves and manual valves along with civil and painting work. All components to be installed were tested for high pressure. Helium gas sniffer technique was used to check micro leaks for new joints for all components before installing for storage tanks. Subsequently, the tanks were tested up to 90 psig SF6 gradually in succession. No pressure drop was observed in storage tanks. This work was carried out as per recommendation of the then particle accelerator committee (PASC). (author)

Gas-puff Z-pinch experiment on the LIMAY-I

International Nuclear Information System (INIS)

Takasugi, K.; Miyamoto, T.; Akiyama, H.; Shimomura, N.; Sato, M.; Tazima, T.

1989-01-01

A gas-puff z-pinch plasma has been produced on the pulsed power generator LIMAY-I at IPP Nagoya University. The stored energy of the generator is 13 kJ, and it generates 600 kV-70 ns-3 Ω power pulse. Ar or He gas is puffed from a hollow nozzle with 18 mm diameter, and a z-pinch plasma is produced by a discharge between 3 mm gap electrodes

Longitudinal gas-density profilometry for plasma-wakefield acceleration targets

Science.gov (United States)

Schaper, Lucas; Goldberg, Lars; Kleinwächter, Tobias; Schwinkendorf, Jan-Patrick; Osterhoff, Jens

2014-03-01

Precise tailoring of plasma-density profiles has been identified as one of the critical points in achieving stable and reproducible conditions in plasma wakefield accelerators. Here, the strict requirements of next generation plasma-wakefield concepts, such as hybrid-accelerators, with densities around 1017 cm-3 pose challenges to target fabrication as well as to their reliable diagnosis. To mitigate these issues we combine target simulation with fabrication and characterization. The resulting density profiles in capillaries with gas jet and multiple in- and outlets are simulated with the fluid code OpenFOAM. Satisfactory simulation results then are followed by fabrication of the desired target shapes with structures down to the 10 μm level. The detection of Raman scattered photons using lenses with large collection solid angle allows to measure the corresponding longitudinal density profiles at different number densities and allows a detection sensitivity down to the low 1017 cm-3 density range at high spatial resolution. This offers the possibility to gain insight into steep density gradients as for example in gas jets and at the plasma-to-vacuum transition.

2D hydrodynamic simulations of a variable length gas target for density down-ramp injection of electrons into a laser wakefield accelerator

Energy Technology Data Exchange (ETDEWEB)

Kononenko, O., E-mail: olena.kononenko@desy.de [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Lopes, N.C.; Cole, J.M.; Kamperidis, C.; Mangles, S.P.D.; Najmudin, Z. [The John Adams Institute for Accelerator Science, The Blackett Laboratory, Imperial College London, SW7 2BZ UK (United Kingdom); Osterhoff, J. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Poder, K. [The John Adams Institute for Accelerator Science, The Blackett Laboratory, Imperial College London, SW7 2BZ UK (United Kingdom); Rusby, D.; Symes, D.R. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Warwick, J. [Queens University Belfast, North Ireland (United Kingdom); Wood, J.C. [The John Adams Institute for Accelerator Science, The Blackett Laboratory, Imperial College London, SW7 2BZ UK (United Kingdom); Palmer, C.A.J. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany)

2016-09-01

In this work, two-dimensional (2D) hydrodynamic simulations of a variable length gas cell were performed using the open source fluid code OpenFOAM. The gas cell was designed to study controlled injection of electrons into a laser-driven wakefield at the Astra Gemini laser facility. The target consists of two compartments: an accelerator and an injector section connected via an aperture. A sharp transition between the peak and plateau density regions in the injector and accelerator compartments, respectively, was observed in simulations with various inlet pressures. The fluid simulations indicate that the length of the down-ramp connecting the sections depends on the aperture diameter, as does the density drop outside the entrance and the exit cones. Further studies showed, that increasing the inlet pressure leads to turbulence and strong fluctuations in density along the axial profile during target filling, and consequently, is expected to negatively impact the accelerator stability.

Refurbishment and retrofitting of SF6 gas storage tanks of the pelletron accelerator

International Nuclear Information System (INIS)

Reddy, G.R.; Datar, V.M.; Parulekar, Y.M.

2015-01-01

The BARC-TIFR Pelletron Accelerator Facility has completed more than twenty six years of successful round-the-clock operation, serving diverse users from institutions within and outside DAE. The main accelerating structure and associated subsystems are housed in the accelerator tank under SF 6 gas medium. During maintenance of the accelerator, the SF 6 gas present in the accelerator tank is transferred in the four storage tanks located on the terrace of the building open to outside environment. These four storage tanks (with ∼ 1/4th of the main tank volume each) are ∼ 4.27 m in diameter and ∼ 10 m in height each and are supported on RCC ring beams which are monolithically connected with the RCC structure below. Over the years, the anchor bolts and the base plates of support structure of storage tanks were found corroded and the foundation RCC ring beam indicated a few corrosion cracks. Health assessment of relevant structures and components were carried out. Considering the limitations of existing anchorage and also giving due considerations for reparability and replaceability, a new anchorage system was designed. The entire refurbishment and retrofitting works pertaining to the four SF 6 gas storage tanks was executed in a time bound manner to comply with the then PASC (Particle Accelerator Safety Committee) recommendations successfully, without disrupting the operations of the round-the-clock running Pelletron Accelerator facility. In addition, the thickness measurements for the storage tanks were performed. The relief valves and rupture disc assemblies across the storage tanks were replaced and reinstalled after introducing appropriate manual valves as suggested by the PASC. A new test set up was fabricated to perform pneumatic testing at the recommended pressure off-line for these relief valves and rupture disc assemblies prior to reinstallation. This paper describes the comprehensive rehabilitation and retrofitting procedures that were carried out at the

Technological acceleration and organizational transformations in the upstream oil and gas industry

International Nuclear Information System (INIS)

Isabelle, M.

2000-12-01

The upstream oil and gas industry experienced a dramatic technological acceleration in the early 1970's. The relationships between the agents in this industry have themselves undergone deep changes since that date. This thesis shows that a tight link exists between the technological acceleration and the organizational transformations in the upstream oil and gas industry. In a first part, it focuses on the economic theory's developments concerning industrial organization. In a second part, it applies these developments to three types of relations: those between the owner-states of hydrocarbon resources and the international petroleum companies; those between the international petroleum companies and their subcontractors; and finally those between the international petroleum companies themselves. (author)

Cleavage of influenza RNA by using a human PUF-based artificial RNA-binding protein–staphylococcal nuclease hybrid

International Nuclear Information System (INIS)

Mori, Tomoaki; Nakamura, Kento; Masaoka, Keisuke; Fujita, Yusuke; Morisada, Ryosuke; Mori, Koichi; Tobimatsu, Takamasa; Sera, Takashi

2016-01-01

Various viruses infect animals and humans and cause a variety of diseases, including cancer. However, effective methodologies to prevent virus infection have not yet been established. Therefore, development of technologies to inactivate viruses is highly desired. We have already demonstrated that cleavage of a DNA virus genome was effective to prevent its replication. Here, we expanded this methodology to RNA viruses. In the present study, we used staphylococcal nuclease (SNase) instead of the PIN domain (PilT N-terminus) of human SMG6 as an RNA-cleavage domain and fused the SNase to a human Pumilio/fem-3 binding factor (PUF)-based artificial RNA-binding protein to construct an artificial RNA restriction enzyme with enhanced RNA-cleavage rates for influenzavirus. The resulting SNase-fusion nuclease cleaved influenza RNA at rates 120-fold greater than the corresponding PIN-fusion nuclease. The cleaving ability of the PIN-fusion nuclease was not improved even though the linker moiety between the PUF and RNA-cleavage domain was changed. Gel shift assays revealed that the RNA-binding properties of the PUF derivative used was not as good as wild type PUF. Improvement of the binding properties or the design method will allow the SNase-fusion nuclease to cleave an RNA target in mammalian animal cells and/or organisms. - Highlights: • A novel RNA restriction enzyme using SNase was developed tor cleave viral RNA. • Our enzyme cleaved influenza RNA with rates >120-fold higher rates a PIN-fusion one. • Our artificial enzyme with the L5 linker showed the highest RNA cleavage rate. • Our artificial enzyme site-selectively cleaved influenza RNA in vitro.

How gas-guzzler conversions can accelerate transportation electrification

Energy Technology Data Exchange (ETDEWEB)

Gremban, R. [California Cars Initiative, Palo Alto, CA (United States)

2010-07-01

This presentation discussed how plug-in hybrid electric vehicles (PHEV) can ramp up to accelerate greenhouse gas reductions. Specific topics that were presented included required battery manufacturing capacity; rapid conversion of light, medium, and heavy-duty ICE vehicles in the United States into battery electric vehicles and PHEVs; the low hanging fruits such as pickups, vans, larger vehicles, and those with defined drive cycles; the economics of gas guzzler conversions; and Canada and Japan policies on conversions. United States' measures supporting electric vehicle/(PHEV) conversions was also addressed. Some examples of converting vehicles to PHEVs were also outlined. The presentation concluded with some key themes to begin now for market penetration. It was concluded that without ICE conversions, market penetration was too slow. figs.

Natural gas co-operation in the Baltic region

International Nuclear Information System (INIS)

Jensen, J.K.

1996-01-01

Co-operation between the gas companies in the Baltic Region has been in place for several years. The overview given in this paper shows that the co-operation has been developed in trade, investments, privatisation and participation in the restructuring process. Finally, through a broad technical co-operation, significant efforts are made to establish common operational practices, codes and standards and the integrity of gas transmission pipelines. The Baltic Region, from a resource and gas interconnection point of view, enjoys a strategic position in the future development of the gas industry in Europe. The Baltic gas sector represents an interesting and growing gas market with the significant gas storage capacity. The region is also located strategically for planned gas interconnections and could serve as a transit corridor for the future gas supplies from western Siberia or the North Sea. This co-operation in the region is being supported by international regulations and agreements such as the Energy Charter between the European Union and the central and east European countries. However, at present the gas industry in the Baltic Region seems to be ahead of these international agreements. It may well be seen that trade arrangements such as Third Party Access are implemented directly by market forces rather than through international agreements. The regional development may thus be a driving force for the implementation of the Internal Energy Market for the gas industry

Repression of mitochondrial translation, respiration and a metabolic cycle-regulated gene, SLF1, by the yeast Pumilio-family protein Puf3p.

Directory of Open Access Journals (Sweden)

Marc Chatenay-Lapointe

Full Text Available Synthesis and assembly of the mitochondrial oxidative phosphorylation (OXPHOS system requires genes located both in the nuclear and mitochondrial genomes, but how gene expression is coordinated between these two compartments is not fully understood. One level of control is through regulated expression mitochondrial ribosomal proteins and other factors required for mitochondrial translation and OXPHOS assembly, which are all products of nuclear genes that are subsequently imported into mitochondria. Interestingly, this cadre of genes in budding yeast has in common a 3'-UTR element that is bound by the Pumilio family protein, Puf3p, and is coordinately regulated under many conditions, including during the yeast metabolic cycle. Multiple functions have been assigned to Puf3p, including promoting mRNA degradation, localizing nucleus-encoded mitochondrial transcripts to the outer mitochondrial membrane, and facilitating mitochondria-cytoskeletal interactions and motility. Here we show that Puf3p has a general repressive effect on mitochondrial OXPHOS abundance, translation, and respiration that does not involve changes in overall mitochondrial biogenesis and largely independent of TORC1-mitochondrial signaling. We also identified the cytoplasmic translation factor Slf1p as yeast metabolic cycle-regulated gene that is repressed by Puf3p at the post-transcriptional level and promotes respiration and extension of yeast chronological life span when over-expressed. Altogether, these results should facilitate future studies on which of the many functions of Puf3p is most relevant for regulating mitochondrial gene expression and the role of nuclear-mitochondrial communication in aging and longevity.

Longitudinal gas-density profilometry for plasma-wakefield acceleration targets

Energy Technology Data Exchange (ETDEWEB)

Schaper, Lucas, E-mail: lschaper01@qub.ac.uk [Universität Hamburg, FB Physik, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg (Germany); Goldberg, Lars; Kleinwächter, Tobias; Schwinkendorf, Jan-Patrick; Osterhoff, Jens [Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg (Germany)

2014-03-11

Precise tailoring of plasma-density profiles has been identified as one of the critical points in achieving stable and reproducible conditions in plasma wakefield accelerators. Here, the strict requirements of next generation plasma-wakefield concepts, such as hybrid-accelerators, with densities around 10{sup 17} cm{sup −3} pose challenges to target fabrication as well as to their reliable diagnosis. To mitigate these issues we combine target simulation with fabrication and characterization. The resulting density profiles in capillaries with gas jet and multiple in- and outlets are simulated with the fluid code OpenFOAM. Satisfactory simulation results then are followed by fabrication of the desired target shapes with structures down to the 10 µm level. The detection of Raman scattered photons using lenses with large collection solid angle allows to measure the corresponding longitudinal density profiles at different number densities and allows a detection sensitivity down to the low 10{sup 17} cm{sup −3} density range at high spatial resolution. This offers the possibility to gain insight into steep density gradients as for example in gas jets and at the plasma-to-vacuum transition.

Regional alveolar partial pressure of oxygen measurement with parallel accelerated hyperpolarized gas MRI.

Science.gov (United States)

Kadlecek, Stephen; Hamedani, Hooman; Xu, Yinan; Emami, Kiarash; Xin, Yi; Ishii, Masaru; Rizi, Rahim

2013-10-01

Alveolar oxygen tension (Pao2) is sensitive to the interplay between local ventilation, perfusion, and alveolar-capillary membrane permeability, and thus reflects physiologic heterogeneity of healthy and diseased lung function. Several hyperpolarized helium ((3)He) magnetic resonance imaging (MRI)-based Pao2 mapping techniques have been reported, and considerable effort has gone toward reducing Pao2 measurement error. We present a new Pao2 imaging scheme, using parallel accelerated MRI, which significantly reduces measurement error. The proposed Pao2 mapping scheme was computer-simulated and was tested on both phantoms and five human subjects. Where possible, correspondence between actual local oxygen concentration and derived values was assessed for both bias (deviation from the true mean) and imaging artifact (deviation from the true spatial distribution). Phantom experiments demonstrated a significantly reduced coefficient of variation using the accelerated scheme. Simulation results support this observation and predict that correspondence between the true spatial distribution and the derived map is always superior using the accelerated scheme, although the improvement becomes less significant as the signal-to-noise ratio increases. Paired measurements in the human subjects, comparing accelerated and fully sampled schemes, show a reduced Pao2 distribution width for 41 of 46 slices. In contrast to proton MRI, acceleration of hyperpolarized imaging has no signal-to-noise penalty; its use in Pao2 measurement is therefore always beneficial. Comparison of multiple schemes shows that the benefit arises from a longer time-base during which oxygen-induced depolarization modifies the signal strength. Demonstration of the accelerated technique in human studies shows the feasibility of the method and suggests that measurement error is reduced here as well, particularly at low signal-to-noise levels. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

Development of the centrifugal pellet injector for JT-60U

Energy Technology Data Exchange (ETDEWEB)

Kizu, Kaname; Hiratsuka, Hajime; Ichige, Hisashi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

2001-03-01

For core fueling of JT-60U plasmas, a repetitive pellet injector which centrifugally accelerates D{sub 2} cubic pellets using a straight rod has been developed. This centrifugal pellet injector can eject trains of up to 40 cubic pellets at frequencies of 1-10 Hz and velocities of 0.3-1.0 km/s. The average pellet mass is 3.6x10{sup 20} atoms/pellet below 0.7 m/s. Key techniques for the development were a mesh structured acceleration component for removing gas sublimated from the pellet and a funnel with an appropriate angle connected just behind the acceleration chamber for introducing the pellet to plasma without destruction. Using the mesh structured components, the horizontal angular distribution of pellets ejected became narrow, because irregular pellet motion caused by sublimated gas was reduced. To investigate the performance of the injector, pellet injection experiments from the low magnetic field side (LFS) were conducted using ohmic heating plasmas. Central fueling and enhanced fueling rate have been observed. D{alpha} intensity around the divertor region was reduced in a pellet injection plasma compared to gas puffing, indicating low recycling rate was maintained with the pellet injection. (author)

Development of the centrifugal pellet injector for JT-60U

International Nuclear Information System (INIS)

Kizu, Kaname; Hiratsuka, Hajime; Ichige, Hisashi

2001-03-01

For core fueling of JT-60U plasmas, a repetitive pellet injector which centrifugally accelerates D 2 cubic pellets using a straight rod has been developed. This centrifugal pellet injector can eject trains of up to 40 cubic pellets at frequencies of 1-10 Hz and velocities of 0.3-1.0 km/s. The average pellet mass is 3.6x10 20 atoms/pellet below 0.7 m/s. Key techniques for the development were a mesh structured acceleration component for removing gas sublimated from the pellet and a funnel with an appropriate angle connected just behind the acceleration chamber for introducing the pellet to plasma without destruction. Using the mesh structured components, the horizontal angular distribution of pellets ejected became narrow, because irregular pellet motion caused by sublimated gas was reduced. To investigate the performance of the injector, pellet injection experiments from the low magnetic field side (LFS) were conducted using ohmic heating plasmas. Central fueling and enhanced fueling rate have been observed. Dα intensity around the divertor region was reduced in a pellet injection plasma compared to gas puffing, indicating low recycling rate was maintained with the pellet injection. (author)

Investigation of the Electron Acceleration by a High-Power Laser and a Density-Tapered Mixed-Gas Cell

Science.gov (United States)

Kim, Jinju; Phung, Vanessa L. J.; Kim, Minseok; Hur, Min-Sup; Suk, Hyyong

2017-10-01

Plasma-based accelerators can generate about 1000 times stronger acceleration field compared with RF-based conventional accelerators, which can be done by high power laser and plasma. There are many issues in this research and one of them is development of a good plasma source for higher electron beam energy. For this purpose, we are investigating a special type of plasma source, which is a density-tapered gas cell with a mixed-gas for easy injection. By this type of special gas cell, we expect higher electron beam energies with easy injection in the wakefield. In this poster, some experimental results for electron beam generation with the density-tapered mixed-gas cell are presented. In addition to the experimental results, CFD (Computational-Fluid-Dynamics) and PIC (Particle-In-Cell) simulation results are also presented for comparison studies.

Accelerating Gas Adsorption on 3D Percolating Carbon Nanotubes.

Science.gov (United States)

Li, Hui; Wen, Chenyu; Zhang, Youwei; Wu, Dongping; Zhang, Shi-Li; Qiu, Zhi-Jun

2016-02-18

In the field of electronic gas sensing, low-dimensional semiconductors such as single-walled carbon nanotubes (SWCNTs) can offer high detection sensitivity owing to their unprecedentedly large surface-to-volume ratio. The sensitivity and responsivity can further improve by increasing their areal density. Here, an accelerated gas adsorption is demonstrated by exploiting volumetric effects via dispersion of SWCNTs into a percolating three-dimensional (3D) network in a semiconducting polymer. The resultant semiconducting composite film is evaluated as a sensing membrane in field effect transistor (FET) sensors. In order to attain reproducible characteristics of the FET sensors, a pulsed-gate-bias measurement technique is adopted to eliminate current hysteresis and drift of sensing baseline. The rate of gas adsorption follows the Langmuir-type isotherm as a function of gas concentration and scales with film thickness. This rate is up to 5 times higher in the composite than only with an SWCNT network in the transistor channel, which in turn results in a 7-fold shorter time constant of adsorption with the composite. The description of gas adsorption developed in the present work is generic for all semiconductors and the demonstrated composite with 3D percolating SWCNTs dispersed in functional polymer represents a promising new type of material for advanced gas sensors.

Lattice Boltzmann accelerated direct simulation Monte Carlo for dilute gas flow simulations.

Science.gov (United States)

Di Staso, G; Clercx, H J H; Succi, S; Toschi, F

2016-11-13

Hybrid particle-continuum computational frameworks permit the simulation of gas flows by locally adjusting the resolution to the degree of non-equilibrium displayed by the flow in different regions of space and time. In this work, we present a new scheme that couples the direct simulation Monte Carlo (DSMC) with the lattice Boltzmann (LB) method in the limit of isothermal flows. The former handles strong non-equilibrium effects, as they typically occur in the vicinity of solid boundaries, whereas the latter is in charge of the bulk flow, where non-equilibrium can be dealt with perturbatively, i.e. according to Navier-Stokes hydrodynamics. The proposed concurrent multiscale method is applied to the dilute gas Couette flow, showing major computational gains when compared with the full DSMC scenarios. In addition, it is shown that the coupling with LB in the bulk flow can speed up the DSMC treatment of the Knudsen layer with respect to the full DSMC case. In other words, LB acts as a DSMC accelerator.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).

Numerical modeling of laser-driven ion acceleration from near-critical gas targets

Science.gov (United States)

Tatomirescu, Dragos; Vizman, Daniel; d’Humières, Emmanuel

2018-06-01

In the past two decades, laser-accelerated ion sources and their applications have been intensely researched. Recently, it has been shown through experiments that proton beams with characteristics comparable to those obtained with solid targets can be obtained from gaseous targets. By means of particle-in-cell simulations, this paper studies in detail the effects of a near-critical density gradient on ion and electron acceleration after the interaction with ultra high intensity lasers. We can observe that the peak density of the gas jet has a significant influence on the spectrum features. As the gas jet density increases, so does the peak energy of the central quasi-monoenergetic ion bunch due to the increase in laser absorption while at the same time having a broadening effect on the electron angular distribution.

Gas system 2015: Press conference 21 January 2016 + Gas consumption by administrative regions

International Nuclear Information System (INIS)

2016-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents some key figures about GRTgaz activity in 2015: Gas consumption resumed despite warm conditions in 2015. Gas demand for power generation in gas-fired power plants has strongly increased, due to favourable economic conditions. 2015 was characterised by the lowest LNG imports to France ever, which entailed a still intensive use of the North-South link, despite transits to Spain and Italy back to 5 year average level. New gas uses and biomethane permitted to avoid 490,000 tonnes of CO 2 emissions in 2015. A second part presents the regional gas consumptions by administrative regions

A Compact and Low Power RO PUF with High Resilience to the EM Side-Channel Attack and the SVM Modelling Attack of Wireless Sensor Networks.

Science.gov (United States)

Cao, Yuan; Zhao, Xiaojin; Ye, Wenbin; Han, Qingbang; Pan, Xiaofang

2018-01-23

Authentication is a crucial security service for the wireless sensor networks (WSNs) in versatile domains. The deployment of WSN devices in the untrusted open environment and the resource-constrained nature make the on-chip authentication an open challenge. The strong physical unclonable function (PUF) came in handy as light-weight authentication security primitive. In this paper, we present the first ring oscillator (RO) based strong physical unclonable function (PUF) with high resilience to both the electromagnetic (EM) side-channel attack and the support vector machine (SVM) modelling attack. By employing an RO based PUF architecture with the current starved inverter as the delay cell, the oscillation power is significantly reduced to minimize the emitted EM signal, leading to greatly enhanced immunity to the EM side-channel analysis attack. In addition, featuring superior reconfigurability due to the conspicuously simplified circuitries, the proposed implementation is capable of withstanding the SVM modelling attack by generating and comparing a large number of RO frequency pairs. The reported experimental results validate the prototype of a 9-stage RO PUF fabricated using standard 65 nm complementary-metal-oxide-semiconductor (CMOS) process. Operating at the supply voltage of 1.2 V and the frequency of 100 KHz, the fabricated RO PUF occupies a compact silicon area of 250 μ m 2 and consumes a power as low as 5.16 μ W per challenge-response pair (CRP). Furthermore, the uniqueness and the worst-case reliability are measured to be 50.17% and 98.30% for the working temperature range of -40∼120 ∘ C and the supply voltage variation of ±2%, respectively. Thus, the proposed PUF is applicable for the low power, low cost and secure WSN communications.

Magnetic discharge accelerating diode for the gas-filled pulsed neutron generators based on inertial confinement of ions

International Nuclear Information System (INIS)

Kozlovskij, K I; Shikanov, A E; Vovchenko, E D; Shatokhin, V L; Isaev, A A; Martynenko, A S

2016-01-01

The paper deals with magnetic discharge diode module with inertial electrostatic ions confinement for the gas-filled pulsed neutron generators. The basis of the design is geometry with the central hollow cathode surrounded by the outer cylindrical anode and electrodes made of permanent magnets. The induction magnitude about 0.1-0.4 T in the central region of the discharge volume ensures the confinement of electrons in the space of hollow (virtual) cathode and leads to space charge compensation of accelerated ions in the centre. The research results of different excitation modes in pulsed high-voltage discharge are presented. The stable form of the volume discharge preserveing the shape and amplitude of the pulse current in the pressure range of 10 -3 -10 -1 Torr and at the accelerating voltage up to 200 kV was observed. (paper)

Classical region of a trapped Bose gas

Energy Technology Data Exchange (ETDEWEB)

Blakie, P Blair [Jack Dodd Centre for Photonics and Ultra-Cold Atoms, University of Otago, Dunedin (New Zealand); Davis, Matthew J [ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, QLD 4072 (Australia)

2007-06-14

The classical region of a Bose gas consists of all single particle modes that have a high average occupation and are well described by a classical field. Highly occupied modes only occur in massive Bose gases at ultra-cold temperatures, in contrast to the photon case where there are highly occupied modes at all temperatures. For the Bose gas the number of these modes is dependent on the temperature, the total number of particles and their interaction strength. In this paper, we characterize the classical region of a harmonically trapped Bose gas over a wide parameter regime. We use a Hartree-Fock approach to account for the effects of interactions, which we observe to significantly change the classical region as compared to the idealized case. We compare our results to full classical field calculations and show that the Hartree-Fock approach provides a qualitatively accurate description of a classical region for the interacting gas.

Characteristics of the magnetic wall reflection model on ion acceleration in gas-puff z pinch

International Nuclear Information System (INIS)

Nishio, M.; Takasugi, K.

2013-01-01

The magnetic wall reflection model was examined with the numerical simulation of the trajectory calculation of particles. This model is for the ions accelerated by some current-independent mechanism. The trajectory calculation showed angle dependency of highest velocities of accelerated particles. This characteristics is of the magnetic wall reflection model, not of the other current-independent acceleration mechanism. Thomson parabola measurements of accelerated ions produced in the gas-puff z-pinch experiments were carried out for the verification of the angle dependency. (author)

Two-dimensional perturbations of the accelerated motion of inhomogeneous gas layers and shells in the interstellar medium

Science.gov (United States)

Krasnobaev, K. V.; Kotova, G. Yu.; Tagirova, R. R.

2015-03-01

The evolution of perturbations in a two-layer spherical shell and a plane layer with a two-step density distribution has been simulated numerically. The clumps formed by instability are shown to have qualitatively different structures, depending on the ratio of the densities in the inner and outer layers of the shell. Inhomogeneities bordered by a dense gas are formed in shells with an outwardly decreasing density. If, however, a denser gas is in the outer layer, then cores surrounded by a more rarefied material appear. These results are used to analyze the expansion of the HII region RCW 82. Since the inhomogeneities observed in the 13CO emission in the outer parts of this region have sharply delineated boundaries, our calculations argue for the model of the expansion of a shell with an outwardly decreasing density. The interaction of an accelerating shell with clumps in front of it has also been investigated. The deformations of a clump during its penetration into the shell and the formation of a groove in the shell gradually fillingwith a cold gas have been revealed. Thereafter, the shell material collapses to form a cumulative jet. As applied to the HII region RCW 82, we conclude that the existence of jets is possible if there are inhomogeneities with a scale of ˜1018 cm in the interstellar medium. The lack of data on such jet flows at the boundary of this region is an additional argument for the model where the inhomogeneous structure of the boundaries is attributable to the development of Rayleigh-Taylor instability.

Effects of instant controlled pressure drop process on physical and sensory properties of puffed wheat snack.

Science.gov (United States)

Yağcı, Sibel

2017-04-01

In this study, research on the development of a puffed wheat snack using the instant controlled pressure drop (DIC) process was carried out. Snack products were produced by expanding moistened wheat under various DIC processing conditions in order to obtain adequate puffing, followed by drying in a hot air dryer. The effects of operational variables such as wheat initial moisture content (11-23% w/w, wet basis), processing pressure (3-5 × 10 2 kPa) and processing time (3-11 min) on the physical (density, color and textural characteristics) and sensory properties of the product were investigated. The physical properties of the wheat snack were most affected by changes in processing pressure, followed by processing time and wheat moisture content. Increasing processing pressure and time often improved expansion and textural properties but led to darkening of the raw wheat color. The most acceptable snack in terms of physical properties was obtained at the lowest wheat moisture content. Sensory analysis suggested that consumer acceptability was optimal for wheat snacks produced at higher processing pressure, medium processing time and lower moisture content. The most desirable conditions for puffed wheat snack production using the DIC process were determined as 11% (w/w) of wheat moisture content, 5 × 10 2 kPa of processing pressure and 7 min of processing time. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Effects of gas liquid ratio on the atomization characteristics of gas-liquid swirl coaxial injectors

Science.gov (United States)

Kang, Zhongtao; Li, Qinglian; Zhang, Jiaqi; Cheng, Peng

2018-05-01

To understand the atomization characteristics and atomization mechanism of the gas-liquid swirl coaxial (GLSC) injector, a back-lighting photography technique has been employed to capture the instantaneous spray images with a high speed camera. The diameter and velocity of the droplets in the spray have been characterized with a Dantec Phase Doppler Anemometry (PDA) system. The effects of gas liquid ratio (GLR) on the spray pattern, Sauter mean diameter (SMD), diameter-velocity distribution and mass flow rate distribution were analyzed and discussed. The results show that the atomization of the GLSC injector is dominated by the film breakup when the GLR is small, and violent gas-liquid interaction when the GLR is large enough. The film breakup dominated spray can be divided into gas acceleration region and film breakup region while the violent gas-liquid interaction dominated spray can be divided into the gas acceleration region, violent gas-liquid interaction region and big droplets breakup region. The atomization characteristics of the GLSC injector is significantly influenced by the GLR. From the point of atomization performance, the increase of GLR has positive effects. It decreases the global Sauter mean diameter (GSMD) and varies the SMD distribution from a hollow cone shape (GLR = 0) to an inverted V shape, and finally slanted N shape. However, from the point of spatial distribution, the increase of GLR has negative effects, because the mass flow rate distribution becomes more nonuniform.

Acceleration Modes and Transitions in Pulsed Plasma Accelerators

Science.gov (United States)

Polzin, Kurt A.; Greve, Christine M.

2018-01-01

Pulsed plasma accelerators typically operate by storing energy in a capacitor bank and then discharging this energy through a gas, ionizing and accelerating it through the Lorentz body force. Two plasma accelerator types employing this general scheme have typically been studied: the gas-fed pulsed plasma thruster and the quasi-steady magnetoplasmadynamic (MPD) accelerator. The gas-fed pulsed plasma accelerator is generally represented as a completely transient device discharging in approximately 1-10 microseconds. When the capacitor bank is discharged through the gas, a current sheet forms at the breech of the thruster and propagates forward under a j (current density) by B (magnetic field) body force, entraining propellant it encounters. This process is sometimes referred to as detonation-mode acceleration because the current sheet representation approximates that of a strong shock propagating through the gas. Acceleration of the initial current sheet ceases when either the current sheet reaches the end of the device and is ejected or when the current in the circuit reverses, striking a new current sheet at the breech and depriving the initial sheet of additional acceleration. In the quasi-steady MPD accelerator, the pulse is lengthened to approximately 1 millisecond or longer and maintained at an approximately constant level during discharge. The time over which the transient phenomena experienced during startup typically occur is short relative to the overall discharge time, which is now long enough for the plasma to assume a relatively steady-state configuration. The ionized gas flows through a stationary current channel in a manner that is sometimes referred to as the deflagration-mode of operation. The plasma experiences electromagnetic acceleration as it flows through the current channel towards the exit of the device. A device that had a short pulse length but appeared to operate in a plasma acceleration regime different from the gas-fed pulsed plasma

GEMINI NEAR INFRARED FIELD SPECTROGRAPH OBSERVATIONS OF THE SEYFERT 2 GALAXY MRK 573: IN SITU ACCELERATION OF IONIZED AND MOLECULAR GAS OFF FUELING FLOWS

Energy Technology Data Exchange (ETDEWEB)

Fischer, Travis C.; Straughn, A. N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Machuca, C.; Crenshaw, D. M.; Baron, F.; Revalski, M.; Pope, C. L. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Diniz, M. R.; Riffel, R. A. [Departamento de Física, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); Schmitt, H. R. [Naval Research Laboratory, Washington, DC 20375 (United States); Storchi-Bergmann, T., E-mail: travis.c.fischer@nasa.gov [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil)

2017-01-01

We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a ∼700 × 2100 pc{sup 2} circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.

Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy MRK 573: In Situ Acceleration of Ionized and Molecular Gas Off Fueling Flows

Science.gov (United States)

Fischer, Travis C.; Machuca, C.; Diniz, M. R.; Crenshaw, D. M.; Kraemer, S. B.; Riffel, R. A.; Schmitt, H. R.; Baron, F.; Storchi-Bergmann, T.; Straughn, A. N.;

Gas system 2016: Press conference 17 January 2017 + Gas consumption by administrative regions

International Nuclear Information System (INIS)

2017-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents some key figures about GRTgaz activity in 2016: A first part presents the national data about gas consumption, production of gas-fired power plants, new gas uses (diesel-gas substitution, biomethane..) and their environmental impacts, and the development of the Internet open-data platform. A second part presents the regional gas consumptions with a focus on industrial clients

Puffed and bothered: Personality, performance, and the effects of stress on checkered pufferfish.

Science.gov (United States)

Pleizier, Naomi; Wilson, Alexander D M; Shultz, Aaron D; Cooke, Steven J

2015-12-01

Although consistent individual-level differences in behaviour are widespread and potentially important in evolutionary and ecological processes, relatively few studies focus on the physiological mechanisms that might underlie and regulate these individual-level differences in wild populations. We conducted experiments to determine whether checkered pufferfish (Sphoeroides testudineus), which were collected from a dynamic (in terms of depth and water temperature) tidal mangrove creek environment in The Bahamas, have consistent individual-level differences in locomotor activity and the response to a simulated predator threat, as well as swimming performance and puffing in response to stressors. The relationships between personality and performance traits were evaluated to determine whether they represented stress-coping styles or syndromes. Subsequently, a displacement study was conducted to determine how personality and performance in the laboratory compared to movements in the field. In addition, we tested whether a physiological dose of the stress hormone cortisol would alter individual consistency in behavioural and performance traits. We found that pufferfish exhibited consistent individual differences in personality traits over time (e.g., activity and the duration of a response to a threat) and that performance was consistent between the lab and the natural enclosure. Locomotor activity and the duration of startled behaviour were not associated with swimming and puffing performance. Locomotor activity, puffing performance, and swimming performance were not related to whether fish returned to the tidal creek of capture after displacement. Similarly, a cortisol treatment did not modify behaviour or performance in the laboratory. The results reveal that consistent individual-level differences in behaviour and performance were present in a population from a fluctuating and physiologically challenging environment but that such traits are not necessarily correlated

Ionised gas kinematics in bipolar H II regions

Science.gov (United States)

Dalgleish, Hannah S.; Longmore, Steven N.; Peters, Thomas; Henshaw, Jonathan D.; Veitch-Michaelis, Joshua L.; Urquhart, James S.

2018-05-01

Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have undertaken a multi-wavelength study of a young, bipolar H II region in the Galactic disc, G316.81-0.06, which lies at the centre of a massive (˜103 M⊙) infrared-dark cloud filament. It is still accreting molecular gas as well as driving a ˜0.2 pc ionised gas outflow perpendicular to the filament. Intriguingly, we observe a large velocity gradient (47.81 ± 3.21 km s-1 pc-1) across the ionised gas in a direction perpendicular to the outflow. This kinematic signature of the ionised gas shows a reasonable correspondence with the simulations of young H II regions. Based on a qualitative comparison between our observations and these simulations, we put forward a possible explanation for the velocity gradients observed in G316.81-0.06. If the velocity gradient perpendicular to the outflow is caused by rotation of the ionised gas, then we infer that this rotation is a direct result of the initial net angular momentum in the natal molecular cloud. If this explanation is correct, this kinematic signature should be common in other young (bipolar) H II regions. We suggest that further quantitative analysis of the ionised gas kinematics of young H II regions, combined with additional simulations, should improve our understanding of feedback at these early stages.

Adaptação à cultura brasileira dos questionários The O'Leary-Sant e PUF, usados para cistite intersticial Adaptación a la cultura brasileña de los cuestionarios The O'Leary-Sant y Puf, usados para cistitis intersticial Adaptation of the O'Leary-Sant and the PUF for the diagnosis of interstitial cystitis for the Brazilian culture

Directory of Open Access Journals (Sweden)

Marcella Lima Victal

2013-04-01

Full Text Available O objetivo deste estudo foi traduzir e adaptar à cultura brasileira os instrumentos The O'Leary-Sant e PUF, utilizados no diagnóstico de cistite intersticial. Foram realizadas as etapas metodológicas recomendadas pela literatura internacional para a adaptação cultural. As etapas de tradução, síntese das traduções e retrotradução foram realizadas satisfatoriamente, e a avaliação das versões sintéticas pelo comitê de especialistas resultou em algumas alterações, assegurando as equivalências entre as versões originais e traduzidas. O PUF foi pré-testado entre 40 sujeitos e The O'Leary-Sant em uma amostra de 50 indivíduos, devido à necessidade de ajustes em decorrência da baixa escolaridade da população. O processo de tradução e adaptação foi realizado com sucesso e os instrumentos, após as modificações, demonstraram ser de fácil compreensão e rápido preenchimento. Entretanto, este é um estudo que antecede o processo de validação e será premente o emprego do instrumento em novas pesquisas para que sejam avaliadas suas propriedades psicométricas.Se objetivó traducir y adaptar a la cultura brasileña los instrumentos The O'Leary-Sant y PUF, utilizados para diagnosticar cistitis intersticial. Fueron efectuadas las etapas metodológicas recomendadas por la literatura internacional para adaptación cultural. Las etapas de traducción, síntesis de traducciones y retrotraducción se realizaron satisfactoriamente, la evaluación de las versiones sintetizadas por parte del comité de especialistas derivó en algunas alteraciones, asegurando las equivalencias entre versiones originales y traducidas. El PUF fue pre-testeado con 40 sujetos y The O'Leary-Sant en muestra de 50 individuos, por la necesidad de ajustes derivados de la baja escolarización de la población. El proceso de traducción y adaptación se efectuó con suceso y los instrumentos luego de las modificaciones demostraron ser de sencilla comprensión y

High-energy electron acceleration in the gas-puff Z-pinch plasma

Energy Technology Data Exchange (ETDEWEB)

Takasugi, Keiichi, E-mail: takasugi@phys.cst.nihon-u.ac.jp [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308 (Japan); Miyazaki, Takanori [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308, Japan and Dept. Innovation Systems Eng., Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585 (Japan); Nishio, Mineyuki [Anan National College of Technology, 265 Aoki, Minobayashi, Anan, Tokushima 774-0017 (Japan)

2014-12-15

The characteristics of hard x-ray generation were examined in the gas-puff z-pinch experiment. The experiment on reversing the voltage was conducted. In both of the positive and negative discharges, the x-ray was generated only from the anode surface, so it was considered that the electrons were accelerated by the induced electromagnetic force at the pinch time.

Zero-leakage multiple key-binding scenarios for SRAM-PUF systems based on the XOR-method

NARCIS (Netherlands)

Kusters, C.J.; Ignatenko, T.; Willems, F.M.J.

2016-01-01

We show that the XOR-method based on linear error-correcting codes can be applied to achieve the secret-key capacity of binary-symmetric SRAM-PUFs. Then we focus on multiple key-bindings. We prove that no information is leaked by all the helper data about a single secret key both in the case where

Zero-leakage multiple key-binding scenarios for SRAM-PUF systems based on the XOR-Method

NARCIS (Netherlands)

Kusters, C.J.; Ignatenko, T.; Willems, F.M.J.

2016-01-01

We show that the XOR-method based on linear error-correcting codes can be applied to achieve the secret-key capacity of binary-symmetric SRAM-PUFs. Then we focus on multiple key-bindings. We prove that no information is leaked by all the helper data about a single secret key both in the case where

Particle acceleration at corotating interaction regions in the three-dimensional heliosphere

International Nuclear Information System (INIS)

Desai, M.I.; Marsden, R.G.; Sanderson, T.R.; Balogh, A.; Forsyth, R.J.; Gosling, J.T.

1998-01-01

We have investigated the relationship between the energetic (∼1MeV) proton intensity (J) and the magnetic compression ratio (C) measured at the trailing edges of corotating interaction regions observed at Ulysses. In general, our results show that the proton intensity was well correlated with the compression ratio, provided that the seed intensity remained constant, consistent with predictions of the Fermi model. Specifically, our results indicate that particles were accelerated to above ∼1MeV in energy at or near the trailing edges of the compression regions observed in the midlatitude southern heliosphere, irrespective of whether the bounding reverse shocks were present or not. On the basis of this, we conclude that shock acceleration is probably not the only mechanism by which particles are accelerated to above ∼1MeV in energy at compression or interaction regions (CIRs). On the basis of magnetic field measurements obtained near the trailing edges of several midlatitude CIRs, we propose that particles could have been accelerated via the Fermi mechanism by being scattered back and forth across the trailing edges of the compression regions by large-amplitude Alfvacute en waves. Our results also show that the proton intensity was well correlated with the compression ratio during low solar activity periods but was essentially independent of C during periods of high solar activity. We suggest that the correlation between J and C was not observed during solar active periods because of significant variations in the seed intensity that result from sporadic contributions from transient solar events. In contrast, the correlation was observable during quiescent periods probably because contributions from transients had decreased dramatically, which allowed the CIRs to accelerate particles out of a seed population whose intensity remained relatively unperturbed. copyright 1998 American Geophysical Union

Studying the effects of nucleating agents on texture modification of puffed corn-fish snack.

Science.gov (United States)

Shahmohammadi, Hamid Reza; Bakar, Jamilah; Rahman, Russly Abdul; Adzhan, Noranizan Mohd

2014-02-01

To improve textural attributes of puffed corn-fish snack, the effects of 1%, 1.5%, and 2% of calcium carbonate, magnesium silicate (talc), sodium bicarbonate as well as 5% and 10% of wheat bran (as the nucleating materials) on textural attributes were studied. Sensory evaluation, bulk density, expansion ratio, maximum force, and count peaks were measured using the Kramer test. The results showed that all of the additives except bran significantly enhanced the texture. Among them, talc at 0.5% was the best to enhance the density and expansion ratio. Effects of using 0.5% talc on puffed corn-fish snack microstructure were studied using scanning electron microscopy. The average cell diameter of 109 ± 48 μm and cell numbers per square centimeter of 67.4 for talc-treated products were obtained, while for nontalc-treated extrudates, average cell diameter of 798 ± 361 μm and cell numbers per square centimeter of 13.9 were found. Incorporation of 0.5% w/w of magnesium silicate reduced (7-fold) the average cell diameter while increased (4-fold) the cell number. © 2014 Institute of Food Technologists®

Southern California Regional Technology Acceleration Program

Energy Technology Data Exchange (ETDEWEB)

Ochoa, Rosibel [Univ. of California, San Diego, CA (United States). Jacobs School of Engineering; Rasochova, Lada [Univ. of California, San Diego, CA (United States). Rady School of Management

2014-09-30

UC San Diego and San Diego State University are partnering to address these deficiencies in the renewable energy space in the greater San Diego region, accelerating the movement of clean energy innovation from the university laboratory into the marketplace, building on the proven model of the William J. von Liebig Center’s (vLC’s) Proof of Concept (POC) program and virtualizing the effort to enable a more inclusive environment for energy innovation and expansion of the number of clean energy start-ups and/or technology licenses in greater California.

acceleration observed in an audio air gas discharge

International Nuclear Information System (INIS)

Ragheb, M.S.

2010-01-01

an audio air gas discharge enclosed in a pyrex glass of 34 mm diameter and 25 cm long , lead to trace the occurrence of an unusual phenomenon. injected relative huge light spots of intense brightness, distributed regularly on the contour and in the center of one of the discharge electrodes, are observed. very high heat is pronounced on both electrodes, while, one of them is higher than the other it attains 660 degree C in 3-4 minutes. series of photographs and registered video films define and clarify the sequence of events that describe the observed phenomenon. the plasma is created by applying an audio power through the electrodes of an air gas discharge of 10 khz and up to 500 watts power supply. the discharge voltage is up to 900 volts: the discharge current flowing through the plasma attains 360 mA. it is found that the discharge system must attain its optimal working conditions in order to produce the amazing phenomena. the obtained plasma is classified as the maximum conditions borders of a γ-discharge type. at these conditions, the corresponding maximum electron temperature and density are 16 eV and 10 15 cm -3 respectively . the observation system succeeded to reveal and to clarify the sequence of the phenomenon events. in addition, by means of the scanning electron microscope and the energy dispersive x- ray systems, the effects on the electrodes surface are investigated and analyzed. the optical observations, in conjunction with the micrograph and surface microanalysis,demonstrate the collision occurrence, of powered agglomerations groups, to the electrode surface. detailed interpretation of that phenomenon suggests a molecular acceleration gaining their energy from the formed plasma due to optimal discharge working conditions. as a consequence, due to the ions agglomerates size this procedure could be considered as a mesoscopic acceleration technique.

Gas-phase hydrosilylation of cyclohexene in an experimental radiation-chemical accelerator apparatus

International Nuclear Information System (INIS)

Pecherkin, A.S.; Sidorov, V.I.; Chernyshev, E.A.

1992-01-01

A process for the synthesis of methylcyclohexyldichlorosilane (a basic monomer for the production of organosilicon photoresists) has been investigated and perfected on an experimental apparatus with an ELV-2 electron accelerator; this synthesis involves gas-phase radiation-induced hydrosilylation of cyclohexene by methyldichlorosilane. Basic characteristics of the yield of the desired product under static conditions were determined. With the help of experiments on the synthesis of methylcyclohexyldichlorosilane in a flow- through mode, the technical features of the process of radiation-chemical hydrosilylation of cyclohexene on an accelerator apparatus were determined and studied, the optimal conditions for the synthesis were determined, and an experimental batch of the desired product was produced

Investigation of pellet acceleration by an arc heated gas gun

International Nuclear Information System (INIS)

Andersen, P.; Andersen, S.A.; Bundgaard, J.; Baekmark, L.; Hansen, B.H.; Jensen, V.O.; Kossek, H.; Michelsen, P.K.; Nordskov, A.; Sass, B.; Soerensen, H.; Weisberg, K.V.

1987-06-01

This report describes work on pellet acceleration by means of an arc heated gas gun. The work is a continuation of the work described in RISO-M-2536. The aim of the work is to obtain velocities well above 2 km/s for 3.2 mm diameter deuterium pellets. By means of a cryogenic arc chamber in which the hydrogen propellant is pre-condensed, extruded deutetrium pellets are accelerated up to a maximum velocity of 1.93 km/s. When increasing the energy input to the arc in order to increase the pellet velocity further the heat input to the extrusion/punching pellet loading mechanism was found to be critical: preparation of pellets became difficult and cooling times between shots became inconveniently long. In order to circumvent this problems the concept of a room temperature hydrogen propellant pellet fed arc chamber was proposed. Preliminary results from acceleration of polyurethane pellets with this arc chamber are described as well as the work of developing of feed pellet guns for this chamber. Finally the report describes design consideration for a high pressure propellant pellet fed arc chamber together with preliminary results obtained with a proto-type arc chamber. (author)

Ion acceleration at the earth's bow shock: A review of observations in the upstream region

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1979-01-01

Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different population of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compresive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e. those near 100 keV) are accelerated at the shock or in the broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

Ion acceleration at the earth's bow shock: a review of observations in the upstream region

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1979-01-01

Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different populations of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compressive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e., those near 100 keV) are accelerated at the shock or in broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

Electron acceleration by a self-diverging intense laser pulse

International Nuclear Information System (INIS)

Singh, K.P.; Gupta, D.N.; Tripathi, V.K.; Gupta, V.L.

2004-01-01

Electron acceleration by a laser pulse having a Gaussian radial and temporal profile of intensity has been studied. The interaction region is vacuum followed by a gas. The starting point of the gas region has been chosen around the point at which the peak of the pulse interacts with the electron. The tunnel ionization of the gas causes a defocusing of the laser pulse and the electron experiences the action of a ponderomotive deceleration at the trailing part of the pulse with a lower intensity rather than an acceleration at the rising part of the laser pulse with a high intensity, and thus gains net energy. The initial density of the neutral gas atoms should be high enough to properly defocus the pulse; otherwise the electron experiences some deceleration during the trailing part of the pulse and the net energy gain is reduced. The rate of tunnel ionization increases with the increase in the laser intensity and the initial density of neutral gas atoms, and with the decreases in the laser spot size, which causes more defocusing of the laser pulse. The required initial density of neutral gas atoms decreases with the increase in the laser intensity and also with the decrease in the laser spot size

Horizontal transfers of two types of puf operons among phototrophic members of the Roseobacter clade

Czech Academy of Sciences Publication Activity Database

Koblížek, Michal; Moulisová, Vladimíra; Muroňová, Markéta; Oborník, Miroslav

2015-01-01

Roč. 60, č. 1 (2015), s. 37-43 ISSN 0015-5632 R&D Projects: GA MŠk ED2.1.00/03.0110; GA ČR GAP501/10/0221; GA ČR GBP501/12/G055 Institutional support: RVO:61388971 Keywords : Rosebacter * horizontal transfer * puf operon s Subject RIV: EE - Microbiology, Virology Impact factor: 1.335, year: 2015

A role of neutral hydrogen in CHS plasmas with reheat and collapse and comparison with JIPP T-IIU tokamak plasmas

International Nuclear Information System (INIS)

Morita, S.; Yamada, H.; Iguchi, H.

1992-09-01

Results are described on NBI plasmas of the Compact Helical System (CHS). An increase in the stored energy, which is called plasma 'reheat', is observed with density peaking when gas puffing is turned off in the high density region. A plasma collapse with large increase in radiation loss occurs even in discharges whose Z eff values (typically, less than 2-3) do not show any increase when the gas puffing is continued. Both phenomena are basically explained by the edge electron temperature due to the difference in the amount of edge hydrogen neutrals. After turning off the gas puffing, the central electron density n e0 shows an increase of 80% and the density peaking factor (n e0 /n-bar e ) changes from 1.0 to 2.0, in typical cases, and a high inward velocity of the impurities appears (v = 20 m/s). The accumulation is studied in relation to the poloidal rotation and the edge temperature. These results are compared with results from plasmas with IOC- and H-modes in the JIPPT-IIU tokamak. (author)

Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

International Nuclear Information System (INIS)

Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R.

2014-01-01

High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target

Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

Energy Technology Data Exchange (ETDEWEB)

Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-04-28

High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

Technological acceleration and organizational transformations in the upstream oil and gas industry; Acceleration technologique et transformations organisationnelles dans l'industrie d'exploration-production d'hydrocarbures

Energy Technology Data Exchange (ETDEWEB)

Isabelle, M

2000-12-15

The upstream oil and gas industry experienced a dramatic technological acceleration in the early 1970's. The relationships between the agents in this industry have themselves undergone deep changes since that date. This thesis shows that a tight link exists between the technological acceleration and the organizational transformations in the upstream oil and gas industry. In a first part, it focuses on the economic theory's developments concerning industrial organization. In a second part, it applies these developments to three types of relations: those between the owner-states of hydrocarbon resources and the international petroleum companies; those between the international petroleum companies and their subcontractors; and finally those between the international petroleum companies themselves. (author)

Classical relativistic ideal gas in thermodynamic equilibrium in a uniformly accelerated reference frame

International Nuclear Information System (INIS)

Louis-Martinez, Domingo J

2011-01-01

A classical (non-quantum-mechanical) relativistic ideal gas in thermodynamic equilibrium in a uniformly accelerated frame of reference is studied using Gibbs's microcanonical and grand canonical formulations of statistical mechanics. Using these methods explicit expressions for the particle, energy and entropy density distributions are obtained, which are found to be in agreement with the well-known results of the relativistic formulation of Boltzmann's kinetic theory. Explicit expressions for the total entropy, total energy and rest mass of the gas are obtained. The position of the center of mass of the gas in equilibrium is found. The non-relativistic and ultrarelativistic approximations are also considered. The phase space volume of the system is calculated explicitly in the ultrarelativistic approximation.

PuF, an antimetastatic and developmental signaling protein, interacts with the Alzheimer’s amyloid-β precursor protein via a tissue-specific proximal regulatory element (PRE

Directory of Open Access Journals (Sweden)

Lahiri Debomoy K

2013-01-01

Full Text Available Abstract Background Alzheimer’s disease (AD is intimately tied to amyloid-β (Aβ peptide. Extraneuronal brain plaques consisting primarily of Aβ aggregates are a hallmark of AD. Intraneuronal Aβ subunits are strongly implicated in disease progression. Protein sequence mutations of the Aβ precursor protein (APP account for a small proportion of AD cases, suggesting that regulation of the associated gene (APP may play a more important role in AD etiology. The APP promoter possesses a novel 30 nucleotide sequence, or “proximal regulatory element” (PRE, at −76/−47, from the +1 transcription start site that confers cell type specificity. This PRE contains sequences that make it vulnerable to epigenetic modification and may present a viable target for drug studies. We examined PRE-nuclear protein interaction by gel electrophoretic mobility shift assay (EMSA and PRE mutant EMSA. This was followed by functional studies of PRE mutant/reporter gene fusion clones. Results EMSA probed with the PRE showed DNA-protein interaction in multiple nuclear extracts and in human brain tissue nuclear extract in a tissue-type specific manner. We identified transcription factors that are likely to bind the PRE, using competition gel shift and gel supershift: Activator protein 2 (AP2, nm23 nucleoside diphosphate kinase/metastatic inhibitory protein (PuF, and specificity protein 1 (SP1. These sites crossed a known single nucleotide polymorphism (SNP. EMSA with PRE mutants and promoter/reporter clone transfection analysis further implicated PuF in cells and extracts. Functional assays of mutant/reporter clone transfections were evaluated by ELISA of reporter protein levels. EMSA and ELISA results correlated by meta-analysis. Conclusions We propose that PuF may regulate the APP gene promoter and that AD risk may be increased by interference with PuF regulation at the PRE. PuF is targeted by calcium/calmodulin-dependent protein kinase II inhibitor 1, which also

Experimental investigation of molecular beam injection in HL-1 tokamak

International Nuclear Information System (INIS)

Yao Lianghua; Diao Guangyao; Wang Zhanhe; Deng Huichen; Luo Junlin; Duan Xuru; Cui Zhengying

1993-07-01

A new method of gas puffing is presented. The molecular beam, formed by high pressure deuterium gas through Larval nozzle and skimmer slit, is injected into the HL-1 vacuum vessel. The deuterium molecular current from the nozzle passing through the skimmer is about 3 x 10 20 /s. At the line average electron density of 5.2 x 10 19 m -3 , the beam velocity is about 100 m/s. As the plasma density and temperature increasing, the influxes of deuterium particles attenuate quickly. When the molecular beam injection (MBI) just returned to normal gas puffing, the D α emission rapidly decreases, meanwhile, the particles move toward plasma center, the electron density is continuously peaking. The line average electron density rising lasts 45 ms. The thermal energy of plasma and confinement time for particles and energy are also increasing. the MBI is a direct and efficient gas fuelling mode, and the injected particles can reach to inside about 8 cm of plasma and q ≅ 2 confinement region. Its efficiency of injection is about 50%. After the MBI, the particle recycling coefficient R on the wall is 0.6 which is 10% lower than that of normal gas puffing

Particle fuelling for long pulse with standard gas puff and supersonic pulsed gas injection

International Nuclear Information System (INIS)

Bucalossi, J.; Tsitrone, E.; Martin, G.

2003-01-01

In addition to the standard gas puff and to the technically complex pellet injection, a novel intermediate method, based on the injection of a supersonic high density cloud of neutrals, has been recently implemented on the Tore Supra tokamak. Fuelling efficiency, in the 30-50% range are found while it lies in the 10-20% range for the gas puff. It is not sensitive to the plasma density and to the additional heating. According to modelling, the increased efficiency is attributed to the very short injection duration compared to the particle confinement time and to the strong cooling of the plasma edge resulting from the massive injection of matter. A feedback loop on the frequency of the injector has been successfully implemented to control the plasma density. In long pulse experiments (>200s), wall saturation has not been reached. Gas puffing rate was typically around 1 Pa.m 3 s -1 while dynamic wall retention around 0.6 Pa.m 3 s -1 . Co-deposited carbon layer could trap such large amounts of gas. A discharge fuelled by supersonic pulsed gas injections exhibits lower wall retention than a gas puff fuelled discharge. (author)

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...

Separated influence of crude oil prices on regional natural gas import prices

International Nuclear Information System (INIS)

Ji, Qiang; Geng, Jiang-Bo; Fan, Ying

2014-01-01

This paper analyses the impact of global economic activity and international crude oil prices on natural gas import prices in three major natural gas markets using the panel cointegration model. It also investigates the shock impacts of the volatility and the increase and decrease of oil prices on regional natural gas import prices. The results show that both global economic activity and international crude oil prices have significant long-term positive effects on regional natural gas import prices. The volatility of international crude oil prices has a negative impact on regional natural gas import prices. The shock impact is weak in North America, lags in Europe and is most significant in Asia, which is mainly determined by different regional policies for price formation. In addition, the response of natural gas import prices to increases and decreases in international crude oil prices shows an asymmetrical mechanism, of which the decrease impact is relatively stronger. - Highlights: • Impacts of world economy and oil prices on regional natural gas prices are analysed • North American natural gas prices are mainly affected by world economy • Asian and European natural gas prices are mainly affected by oil prices • The volatility of oil prices has a negative impact on regional natural gas prices • The response of natural gas import prices to oil prices up and down shows asymmetry

Ionization front accelerator

International Nuclear Information System (INIS)

Olson, C.L.

1975-01-01

In a recently proposed linear collective accelerator, ions are accelerated in a steep, moving potential well created at the head of an intense relativistic electron beam. The steepness of the potential well and its motion are controlled by the external ionization of a suitable background gas. Calculations concerning optimum choices for the background gas and the ionization method are presented; a two-step photoionization process employing Cs vapor is proposed. In this process, a super-radiant light source is used to excite the gas, and a UV laser is used to photoionize the excited state. The appropriate line widths and coupled ionization growth rate equations are discussed. Parameter estimates are given for a feasibility experiment, for a 1 GeV proton accelerator, and for a heavy ion accelerator (50 MeV/nucleon uranium). (auth)

Natural gas supply and demand projections for the Asia-Pacific region

International Nuclear Information System (INIS)

Khin, J.A.

1992-01-01

The phenomenon of rapid economic growth in the Asia Pacific has inevitably led the countries of this region to expand and diversify their energy sources in order to satisfy their burgeoning energy demands. Natural gas has become an increasingly marketable energy source in this region benefitting from vast reserves and its advantages as an environmentally clean fuel. As a result of the impact of the two oil shocks of the 1970's on the Asia Pacific economy, the governments in the region set about the development of energy strategies which would make their national economies more resilient to the instabilities of world energy price and supply. The Japanese Gas Industry has estimated that the overall rise in demand for energy in Asia, set at an average rate of 3.7% per annum, will see a corresponding growth in demand for natural gas at 5%. Experts from a number of major oil companies, such as Exxon, expect an annual growth in the Asian natural gas market of 6.0 to 6.3%. These figures are over shadowed by the worldwide demand for natural gas which is expected to gain an 8% increase within the next two decades. Approximately 8.75% of the world's proven natural gas reserves are held in Asia-Pacific region (Table I). Most of the region's natural gas production will provide over 100 years of supply. A review of natural gas supply/demand in the Asia-Pacific region is presented in sub-regions, namely ASIAN, Northeast Asia, the Indian Subcontinent and Oceania

Probing electron acceleration and x-ray emission in laser-plasma accelerators

International Nuclear Information System (INIS)

Thaury, C.; Ta Phuoc, K.; Corde, S.; Brijesh, P.; Lambert, G.; Malka, V.; Mangles, S. P. D.; Bloom, M. S.; Kneip, S.

2013-01-01

While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam, is focused on the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion, which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction length to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied

Gas flow and dust acceleration in a cometary Knudsen layer

CERN Document Server

Skorov, Yu V

1999-01-01

An analytical model of the innermost gas-dust coma region is proposed. The kinetic Knudsen layer adjacent to the surface of the cometary nucleus, where the initially non-equilibrium velocity distribution function of gas molecules $9 relaxes to Maxwell equilibrium distribution function and, as a result, the macro-characteristics of gas and dust flows vary several-fold, is considered. The gas phase model is based on the equations for mass, momentum and energy flux $9 conservation, and is a natural development of the Anisimov (1968) and Cercignani (1981) approaches. The analytical relations between the characteristics of the gas flow on the boundaries of the non- equilibrium layer and the $9 characteristics of the returning gas flow adsorbed by the surface are determined. These values form a consistent basis both for hydrodynamic models of the inner coma and for jet force models. Three particular models are presented: $9 (1) sublimation of a polyatomic one-component gas; (2) sublimation of a two-component polyat...

Sizing of SRAM Cell with Voltage Biasing Techniques for Reliability Enhancement of Memory and PUF Functions

Directory of Open Access Journals (Sweden)

Chip-Hong Chang

2016-08-01

Full Text Available Static Random Access Memory (SRAM has recently been developed into a physical unclonable function (PUF for generating chip-unique signatures for hardware cryptography. The most compelling issue in designing a good SRAM-based PUF (SPUF is that while maximizing the mismatches between the transistors in the cross-coupled inverters improves the quality of the SPUF, this ironically also gives rise to increased memory read/write failures. For this reason, the memory cells of existing SPUFs cannot be reused as storage elements, which increases the overheads of cryptographic system where long signatures and high-density storage are both required. This paper presents a novel design methodology for dual-mode SRAM cell optimization. The design conflicts are resolved by using word-line voltage modulation, dynamic voltage scaling, negative bit-line and adaptive body bias techniques to compensate for reliability degradation due to transistor downsizing. The augmented circuit-level techniques expand the design space to achieve a good solution to fulfill several otherwise contradicting key design qualities for both modes of operation, as evinced by our statistical analysis and simulation results based on complementary metal–oxide–semiconductor (CMOS 45 nm bulk Predictive Technology Model.

Molecular ion acceleration using tandem accelerator

Energy Technology Data Exchange (ETDEWEB)

Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1996-12-01

In TIARA compound beam radiation system, cluster beams have been produced using 3 MV tandem accelerator (9SDH-2) to supply them to various radiation on injection experiments. Till now, productions of C{sub 2-8}, Si{sub 2-4} and O{sub 2} and their accelerations up to 6 MeV have been succeeded. This study aimed at production and acceleration of B{sub 2-4} and LiF. Anion clusters were produced using the conventional ion source of cesium sputter type. The proportions of atoms, molecules and clusters elicited from the ion source were varied depending on the material`s properties and the operating conditions of ion source such as sample temperature, sputter voltage and the shape of sample. The anion clusters were accelerated toward the high voltage terminal in the center of tandem accelerator, leading to cations through losing their electrons by the collision to N{sub 2} gas in a charge conversion cell at the terminal. Positively charged cluster ions could be obtained by modulating the pressure of N{sub 2} gas. Thus, B{sub 2} (64 nA), B{sub 3} (4.4 nA) and B{sub 4} (2.7 nA) have been produced and their maximum survival probabilities were higher than those of carbon or silicon clusters. In addition, the relationship between beam current and gas pressure was investigated for Bn (n = 2-4) and LiF. (M.N.)

Particle Acceleration in a Statistically Modeled Solar Active-Region Corona

Science.gov (United States)

Toutounzi, A.; Vlahos, L.; Isliker, H.; Dimitropoulou, M.; Anastasiadis, A.; Georgoulis, M.

2013-09-01

Elaborating a statistical approach to describe the spatiotemporally intermittent electric field structures formed inside a flaring solar active region, we investigate the efficiency of such structures in accelerating charged particles (electrons). The large-scale magnetic configuration in the solar atmosphere responds to the strong turbulent flows that convey perturbations across the active region by initiating avalanche-type processes. The resulting unstable structures correspond to small-scale dissipation regions hosting strong electric fields. Previous research on particle acceleration in strongly turbulent plasmas provides a general framework for addressing such a problem. This framework combines various electromagnetic field configurations obtained by magnetohydrodynamical (MHD) or cellular automata (CA) simulations, or by employing a statistical description of the field's strength and configuration with test particle simulations. Our objective is to complement previous work done on the subject. As in previous efforts, a set of three probability distribution functions describes our ad-hoc electromagnetic field configurations. In addition, we work on data-driven 3D magnetic field extrapolations. A collisional relativistic test-particle simulation traces each particle's guiding center within these configurations. We also find that an interplay between different electron populations (thermal/non-thermal, ambient/injected) in our simulations may also address, via a re-acceleration mechanism, the so called `number problem'. Using the simulated particle-energy distributions at different heights of the cylinder we test our results against observations, in the framework of the collisional thick target model (CTTM) of solar hard X-ray (HXR) emission. The above work is supported by the Hellenic National Space Weather Research Network (HNSWRN) via the THALIS Programme.

Gas blanket fueling of a tokamak reactor

International Nuclear Information System (INIS)

Gralnick, S.L.

1978-01-01

The purpose of this paper is a speculative investigation of the potential of fueling a Tokamak by introducing a sufficiently large quantity of gaseous deuterium and tritium at the vacuum wall boundary. It is motivated by two factors: current generation tokamaks are, in a manner of speaking, fueled from the edge quite successfully as is evidenced by pulse lengths that are long compared to particle recycling times, and by rapid plasma density increase produced by gas puffing, alternative, deep penetration fueling techniques that have been proposed possess severe technological problems and large costs

Experimental study of collective acceleration of light and heavy ions from a localized gas cloud

International Nuclear Information System (INIS)

Floyd, L.E. IV.

1984-01-01

An experimental investigation into the collective acceleration of various gaseous atoms (H, D, He, N, Ne, Ar, Kr, Xe) is presented. A localized gas cloud is formed using a fast rise puff valve immediately downstream of an intense relativistic electron beam diode. The diode consists of a tungsten needle cathode and a stainless steel anode with a hole on axis. The diode is driven by an electron beam generator system consisting of a Marx generator, Blumlein line, and transmission line transformer. It produces a 1.5 MV, 35 kA, 30 ns FWHM electrical pulse measured at the diode. The resulting electron beam has nu/γ approx. 1 and is about six times the vacuum space charge limiting current in the downstream drift chamber. Ions are produced during the impact of the electron beam with the gas cloud and are accelerated to high energy by collective effects associated with the electron beam space charge. Ion energy diagnostics include fast neutron counting, nuclear activation of stacked foils, measurement of time of flight using direct intercept current collector probes, and range/energy analysis of nuclear track plates. The principal result of the experiments was that all ion species were accelerated to a maximum velocity of 0.1c, corresponding to an energy of 4.7 MeV/nucleon. Energy spectra obtained from stacked foil activation for accelerated hydrogen and deuterium were found to be approximately exponential in character

Beam-front dynamics and ion acceleration in drifting intense relativistic electron beams

International Nuclear Information System (INIS)

Alexander, K.F.; Hintze, W.

1976-01-01

Collective ion acceleration at the injection of a relativistic electron beam into a low-pressure gas or a plasma is discussed and its strong dependence on the beam-front dynamics is shown. A simple one-dimensional model taking explicitly into account the motion and ionizing action of the ions in the beam-front region is developed for the calculation of the beam drift velocity. The obtained pressure dependence is in good agreement with experimental data. The energy distribution is shown of the ions accelerated in the moving potential well of the space charge region. Scaling laws for the beam-front dynamics and ion acceleration are derived. (J.U.)

Oil and gas, strategic regional cooperation between Persian Gulf countries

Energy Technology Data Exchange (ETDEWEB)

Zalloi, Mir Mahdi

2010-09-15

Almost two-thirds of proven oil and a third of world natural gas resources are in the Persian Gulf countries. Unfortunately strategic region of Persian Gulf in the past three decades faced with many security challenges due to wars and political conflicts. For security in this region, there are several methods such as military treaties between regional countries or Military presence of foreign countries, but historical evidence has shown, none of them could not guarantee the stable security in this region. The regional cooperation between countries can be replaced to mentioned methods. IPI Gas pipeline is an objective sample for this regional cooperation.

Gluon gas viscosity in nonperturbative region

International Nuclear Information System (INIS)

Il'in, S.V.; Mogilevskij, O.A.; Smolyanskij, S.A.; Zinov'ev, G.M.

1992-01-01

Using the Green-Kubo-type formulae and the cutoff model motivated by Monte Carlo lattice gluodynamics simulations we find the temperature behaviour of shear viscosity of gluon gas in the region of deconfinement phase transition. 22 refs.; 1 fig. (author)

A light-gas gun for acceleration of pellets of solid D2

International Nuclear Information System (INIS)

Nordskov, A.; Skovgaard, H.; Soerensen, H.; Weisberg, K.V.

1980-10-01

A gun has been designed and built to be used for injecting solid D 2 pellets into a small tokamak for pellet-plasma interaction studies. The pellets are formed and accelerated at temperatures close to those of liquid helium. They are propelled with pressurised H 2 -gas; the pressure arises when a quantity of solid H 2 placed in the gun barrel behind the pellet is pulse heated. Pellet velocities up to 240 m/s have been obtained. The directional accuracy is better than 0.2deg and the repetition rate is one firing every five minutes. The pellet volume is 0.6 mm 3 (2 x 10 19 molecules) while the quantity of propeller gas used is around 12 x 10 19 molecules. (author)

Technological acceleration and organizational transformations in the upstream oil and gas industry; Acceleration technologique et transformations organisationnelles dans l'industrie d'exploration-production d'hydrocarbures

Energy Technology Data Exchange (ETDEWEB)

Isabelle, M

2000-12-15

The upstream oil and gas industry experienced a dramatic technological acceleration in the early 1970's. The relationships between the agents in this industry have themselves undergone deep changes since that date. This thesis shows that a tight link exists between the technological acceleration and the organizational transformations in the upstream oil and gas industry. In a first part, it focuses on the economic theory's developments concerning industrial organization. In a second part, it applies these developments to three types of relations: those between the owner-states of hydrocarbon resources and the international petroleum companies; those between the international petroleum companies and their subcontractors; and finally those between the international petroleum companies themselves. (author)

The generalized model of organization and planning of regional gas supply monitoring

Directory of Open Access Journals (Sweden)

Maria V. Shevchenko

2015-12-01

Full Text Available At the moment, gas is one of the most promising types of fuel in Ukraine. In this regard, the problems associated with its transportation in the regional system of gas supply are relevant. Now it is not completely solved and needs detailed study the problem of monitoring the regional gas supply system. Aim: The aim of the study is to improve the efficiency of the regional gas supply system at the expense of the organization and planning of gas transport monitoring and, in the future, the synthesis of the monitoring system of regional gas supply. Materials and Methods: The generalized model of organization and planning of monitoring regional gas suppliers were developed to achieve this goal. It allows making decisions on the organization of the monitoring system. In addition, this model makes it possible to plan under conditions of multicriteriality and uncertainty of the source data. Results: The basic criteria and constraints for solving the problem of organizing and planning the monitoring system of regional gas supply are proposed in this work. The corresponding computations were made to confirm the assumptions. The calculations were carried out in context of uncertainty of input data using a set of methods for the analysis of hierarchies, exhaustive search, as well as the methods of decision making in context of uncertainty.

Natural gas in Asia: Trade, markets and regional institutions

International Nuclear Information System (INIS)

Vivoda, Vlado

2014-01-01

Natural gas trade in Asia has been dominated by long-established market structures, under which liquefied natural gas (LNG) has remained indexed based on the price of crude oil. High transaction costs in the region in recent years imply that the regional market is sub-optimally organized. Since 2010, the continued prevalence of oil-indexation has had the most adverse effect on Japan, the world’s largest LNG importer. In response, Japan implemented several strategies to challenge traditional LNG pricing mechanisms in the region and ultimately reduce transaction costs. Japan’s efforts include an increase in the share of spot and short-term purchases, sourcing new supplies from the United States under alternative pricing arrangements and driving regional buyer cooperation. This paper evaluates the potential effect of Japan’s LNG strategy on regional pricing in the broader institutional context, arguing that LNG pricing in the region will only partially shift away from oil-indexation by the end of the decade. While recent cooperation among regional LNG importers indicates that there may be scope for change in the regional institutional setting, the degree of cooperation is insufficient to have a profound effect on regional pricing. - Highlights: • Sub-optimal natural gas market outcomes in Asia since 2010. • Asian buyers have challenged oil-indexation in the region. • Concrete evidence of Japan-led buyer cooperation since 2013. • Pricing will only partially shift from oil-indexation by 2020. • Security of supply remains a top policy priority

Electrostatic analysis of 750 keV DC accelerator

International Nuclear Information System (INIS)

Kumar, Abhay; Dwivedi, Jishnu; Jana, Arup Ratan

2011-01-01

The indigenously developed 750 keV DC accelerator working at RRCAT for the last 5 years uses SF 6 at 6 bar pressure as the insulating gas. The green house potential of this gas is about 22,000 times more than that of CO 2 gas. An electrostatic analysis of this accelerator was performed in order to probe the necessity of using this gas with a very elaborate gas handling system. The DC accelerator is approximated by a 2-D axisymmetric model in ANSYS and voltages were defined at the individual stages of the accelerating tube. The result of the study shows that the present design needs SF 6 gas and the pressure vessel dimensions need to be modified to operate the DC accelerator with environmentally friendly N 2 -CO 2 mixture. This paper presents the methodology of the analysis, discusses the DC accelerator finite element model and presents the results of the analysis. The paper also proposes changes in the DC accelerator design to run the accelerator with N 2 -CO 2 mixture. (author)

Investigation of local carbon transport in the ASDEX Upgrade divertor using {sup 13}CH{sub 4} puffing

Energy Technology Data Exchange (ETDEWEB)

Pugno, R. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)], E-mail: Roberto.Pugno@ipp.mpg.de; Krieger, K. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Airila, M.; Aho-Mantila, L. [Helsinki University of Technology, Association EURATOM-Tekes, P.O. Box 4100, FI-02015 TKK (Finland); Kreter, A.; Brezinsek, S. [Institut fuer Plasmaphysik, Forschungzentrum Juelich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Rohde, V.; Coster, D.; Chankin, A.; Wischmeier, M. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

2009-06-15

To investigate the combined effect of re-deposition, re-erosion and local transport, known quantities of {sup 13}CH{sub 4} were puffed at the end of the 2007 experimental campaign in the ASDEX Upgrade outboard divertor. Exposed tiles were carefully removed for analysis. The amount of {sup 13}C locally deposited was measured by nuclear reaction analysis (NRA) and colorimetry. About 100% of injected carbon is deposited within a {+-} 15 cm extension in the toroidal direction. In contrast to H-mode results where re-deposition was exclusively downstream, in L-mode, more than one third of the injected hydrocarbon is found upstream. Colorimetric analysis of images taken with different lighting angles to the surface reveals a strong asymmetry in the carbon deposition pattern with respect to the injection facing/averting side of the surface roughness, with 4x thicker layers on the side facing the puffing location. The deposition pattern deviates clearly from the magnetic trajectories showing the effect of downward and radial drifts. ERO modelling of a similar experiment carried out in 2003 in H-mode background plasma can nicely reproduce the toroidal deposition pattern but drifts are not yet satisfactory described.

Application of gas-cooled Accelerator Driven System (ADS) transmutation devices to sustainable nuclear energy development

Energy Technology Data Exchange (ETDEWEB)

Abanades, A., E-mail: abanades@etsii.upm.es [ETSII/Universidad Politecnica de Madrid, J.Gutierrez Abascal, 2-28006 Madrid (Spain); Garcia, C.; Garcia, L. [Instituto Superior de Tecnologia y Ciencias Aplicadas. Quinta de los, Molinos, Ave. Salvador Allende y Luaces, Ciudad de la Habana, CP 10400, Apartado Postal 6163 (Cuba); Escriva, A.; Perez-Navarro, A. [Instituto de Ingenieria Energetica, Universidad Politecnica de Valencia, C.P. 46022 Valencia (Spain); Rosales, J. [Instituto Superior de Tecnologia y Ciencias Aplicadas. Quinta de los, Molinos, Ave. Salvador Allende y Luaces, Ciudad de la Habana, CP 10400, Apartado Postal 6163 (Cuba)

2011-06-15

Highlights: > Utilization of Accelerator Driven System (ADS) for Hydrogen production. > Evaluation of the potential use of gas-cooled ADS for a sustainable use of Uranium resources by transmutation of nuclear wastes, electricity and Hydrogen production. > Application of the Sulfur-Iodine thermochemical process to subcritical systems. > Application of CINDER90 to calculate burn-up in subcritical systems. - Abstract: The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fuel flexibility opening the possibility to reduce the nuclear stockpile producing energy from actual LWR irradiated fuel with an efficiency of 45-46%, either in the form of Hydrogen, electricity, or both.

Tunable porous structure of carbon nanosheets derived from puffed rice for high energy density supercapacitors

Science.gov (United States)

Hou, Jianhua; Jiang, Kun; Tahir, Muhammad; Wu, Xiaoge; Idrees, Faryal; Shen, Ming; Cao, Chuanbao

2017-12-01

The development of green and clean synthetic techniques to overcome energy requirements have motivated the researchers for the utilization of sustainable biomass. Driven by this desire we choose rice as starting materials source. After the explosion effect, the precursor is converted into puffed rice with a honeycomb-like structures composed of thin sheets. These honeycomb-like macrostructures, effectively prevent the cross-linking tendency towards the adjacent nanosheets during activation process. Furthermore, tuneable micro/mesoporous structures with ultrahigh specific surface areas (SBET) are successfully designed by KOH activation. The highest SBET of 3326 m2 g-1 with optimized proportion of small-mesopores is achieved at 850 °C. The rice-derived porous N-doped carbon nanosheets (NCS-850) are used as the active electrode materials for supercapacitors. It exhibites high specific capacitance specifically of 218 F g-1 at 80 A g-1 in 6 M KOH and a high-energy density of 104 Wh kg-1 (53 Wh L-1) in the ionic liquid electrolytes. These are the highest values among the reported biomass-derived carbon materials for the best of our knowledge. The present work demonstrates that the combination of "puffing effect" and common chemical activation can turn natural products such as rice into functional products with prospective applications in high-performance energy storage devices.

Effect of Machine Smoking Intensity and Filter Ventilation Level on Gas-Phase Temperature Distribution Inside a Burning Cigarette

Directory of Open Access Journals (Sweden)

Li Bin

2015-01-01

Full Text Available Accurate measurements of cigarette coal temperature are essential to understand the thermophysical and thermo-chemical processes in a burning cigarette. The last system-atic studies of cigarette burning temperature measurements were conducted in the mid-1970s. Contemporary cigarettes have evolved in design features and multiple standard machine-smoking regimes have also become available, hence there is a need to re-examine cigarette combustion. In this work, we performed systematic measurements on gas-phase temperature of burning cigarettes using an improved fine thermocouple technique. The effects of machine-smoking parameters (puff volume and puff duration and filter ventilation levels were studied with high spatial and time resolutions during single puffs. The experimental results were presented in a number of differ-ent ways to highlight the dynamic and complex thermal processes inside a burning coal. A mathematical distribution equation was used to fit the experimental temperature data. Extracting and plotting the distribution parameters against puffing time revealed complex temperature profiles under different coal volume as a function of puffing intensities or filter ventilation levels. By dividing the coal volume prior to puffing into three temperature ranges (low-temperature from 200 to 400 °C, medium-temperature from 400 to 600 °C, and high-temperature volume above 600 °C by following their development at different smoking regimes, useful mechanistic details were obtained. Finally, direct visualisation of the gas-phase temperature through detailed temperature and temperature gradient contour maps provided further insights into the complex thermo-physics of the burning coal. [Beitr. Tabakforsch. Int. 26 (2014 191-203

Accelerating the three dimensions of E and P clockspeed - A novel strategy for optimizing utility in the Oil and Gas industry

International Nuclear Information System (INIS)

Weijermars, Ruud

2009-01-01

As the global Oil and Gas Industry enters its third, late lifecycle stage (outlined in the introduction of this study), new strategies and conceptual tools are needed to postpone - or reverse - the decline of the E and P industry. The problem is this: the late lifecycle is principally heralded by limited supply due to finite hydrocarbon reserves, while energy demand soars as world population and the global economy continue to grow. This study therefore proposes a framework through which an E and P company can critically assess its capability in accelerating lag-time between exploration and production. In the first part of this paper (Sections 1-3), the need for a phase-shift toward faster clockspeeds for the Oil and Gas industry is argued to be an important step to close the energy supply gap. In the second part of this paper (Sections 4-6), the strategy concept of clockspeed acceleration is further elaborated and optimization methods for the three principal dimensions of E and P clockspeed acceleration are discussed. The three Clockspeed Accelerators TM are: workflow speed, improvement rate of Uncertainty Mitigation and accrual speed of portfolio value. The third part of this paper (Sections 7-11) presents the empirical analysis of E and P clockspeed performance for two peer groups (IOC supermajors and public private partnership NOCs) comprising six companies each. The acceleration of E and P clockspeed can help to optimize production levels of conventional and unconventional oil, and includes diversification strategies that replace non-renewables with renewables. In summary, E and P Clockspeed Accelerators provide the gearshift instruments that enable the energy industry to better meet the required demand/supply ratios. The results of this study translate into the following deliverables for practical use by Oil and Gas professionals: -insight into the concept of clockspeed in E and P industry setting, -use of Clockspeed Accelerators TM as gearshift lever tools

Focusing mechanisms in the Pulselac CU accelerator

International Nuclear Information System (INIS)

Johnson, D.J.; Lockner, T.R.

1986-06-01

The post-acceleration of a 400 keV, 10 kA proton beam by a 200 kV magnetically insulated gap is investigated. The deflection from self and applied E and B fields are measured and compared to calculated values. We find that the beam is inadequately space-charge neutralized without gas puffs in regions of applied-B field to allow efficient transport. The beam is also non-current neutralized in these regions leading to self-magnetic deflection. The applied-B field is used to focus the beam both directly as a solenoidal lens and indirectly by defining the equipotential surfaces in the accelerating gap. It is also pointed out how azimuthal asymmetries in the beam current density and cathode plasma cause beam self-field asymmetries that lead to emittance growth. 4 refs., 4 figs

Longitudinal and transverse dynamics of ions from residual gas in an electron accelerator

Science.gov (United States)

Gamelin, A.; Bruni, C.; Radevych, D.

2018-05-01

The ion cloud produced from residual gas in an electron accelerator can degrade machine performances and produce instabilities. The ion dynamics in an accelerator is governed by the beam-ion interaction, magnetic fields and eventual mitigation strategies. Due to the fact that the beam has a nonuniform transverse size along its orbit, the ions move longitudinally and accumulate naturally at some points in the accelerator. In order to design effective mitigation strategies it is necessary to understand the ion dynamics not only in the transverse plane but also in the longitudinal direction. After introducing the physics behind the beam-ion interaction, we show how to get accumulation points for a realistic electron storage ring lattice. Simulations of the ion cloud dynamics, including the effect of magnetic fields on the ions, clearing electrodes and clearing gaps are shown. Longitudinal ion trapping due to the magnetic mirror effect in the dipole fringe fields is also detailed. Finally, the effectiveness of clearing electrode using longitudinal clearing fields is discussed and compared to clearing electrodes producing transverse field only.

76 FR 23543 - The Jobs and Innovation Accelerator Challenge; a Coordinated Initiative To Advance Regional...

Science.gov (United States)

2011-04-27

... Jobs and Innovation Accelerator Challenge; a Coordinated Initiative To Advance Regional Competitiveness... Federal resources to support regional innovation and sustainable economic prosperity. Knowing that regional innovation clusters provide a globally proven approach for developing economic prosperity, this...

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

Cluster in the Auroral Acceleration Region

Science.gov (United States)

Pickett, Jolene S.; Fazakerley, Andrew N.; Marklund, Gorun; Dandouras, Iannis; Christopher, Ivar W.; Kistler, Lynn; Lucek, Elizabeth; Masson, Arnaud; Taylor, Matthew G.; Mutel, Robert L.;

Methane Emissions from Natural Gas in the Urban Region of Boston, Massachusetts

Science.gov (United States)

McKain, K.; Down, A.; Raciti, S. M.; Budney, J.; Hutyra, L.; Floerchinger, C. R.; Herndon, S. C.; Zahniser, M. S.; Nehrkorn, T.; Jackson, R. B.; Phillips, N. G.; Wofsy, S. C.

2014-12-01

Methane emissions from the natural gas supply chain must be quantified to assess environmental impacts of natural gas and to develop emission reduction strategies. We report natural gas emission rates for one year in the urban region of Boston, MA, using an atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission rate, 20.6 ± 1.7 (95 % CI) g CH4 m-2 yr-1. Simultaneous observations of atmospheric ethane, compared with the ethane to methane ratio in pipeline gas, demonstrate that natural gas accounted for 58 - 100 % of methane emissions, depending on season. Using government statistics and geospatial data on energy consumption, we estimate the fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end-use, was 2.9 ± 0.3 % in the Boston urban region, compared to 1.1 % inferred by the Massachusetts greenhouse gas inventory.

Ion Acceleration by Double Layers with Multi-Component Ion Species

Science.gov (United States)

Good, Timothy; Aguirre, Evan; Scime, Earl; West Virginia University Team

2017-10-01

Current-free double layers (CFDL) models have been proposed to explain observations of magnetic field-aligned ion acceleration in plasmas expanding into divergent magnetic field regions. More recently, experimental studies of the Bohm sheath criterion in multiple ion species plasma reveal an equilibration of Bohm speeds at the sheath-presheath boundary for a grounded plate in a multipole-confined filament discharge. We aim to test this ion velocity effect for CFDL acceleration. We report high resolution ion velocity distribution function (IVDF) measurements using laser induced fluorescence downstream of a CFDL in a helicon plasma. Combinations of argon-helium, argon-krypton, and argon-xenon gases are ionized and measurements of argon or xenon IVDFs are investigated to determine whether ion acceleration is enhanced (or diminished) by the presence of lighter (or heavier) ions in the mix. We find that the predominant effect is a reduction of ion acceleration consistent with increased drag arising from increased gas pressure under all conditions, including constant total gas pressure, equal plasma densities of different ions, and very different plasma densities of different ions. These results suggest that the physics responsible for acceleration of multiple ion species in simple sheaths is not responsible for the ion acceleration observed in these expanding plasmas. Department of Physics, Gettysburg College.

Particle acceleration in solar active regions being in the state of self-organized criticality.

Science.gov (United States)

Vlahos, Loukas

We review the recent observational results on flare initiation and particle acceleration in solar active regions. Elaborating a statistical approach to describe the spatiotemporally intermittent electric field structures formed inside a flaring solar active region, we investigate the efficiency of such structures in accelerating charged particles (electrons and protons). The large-scale magnetic configuration in the solar atmosphere responds to the strong turbulent flows that convey perturbations across the active region by initiating avalanche-type processes. The resulting unstable structures correspond to small-scale dissipation regions hosting strong electric fields. Previous research on particle acceleration in strongly turbulent plasmas provides a general framework for addressing such a problem. This framework combines various electromagnetic field configurations obtained by magnetohydrodynamical (MHD) or cellular automata (CA) simulations, or by employing a statistical description of the field’s strength and configuration with test particle simulations. We work on data-driven 3D magnetic field extrapolations, based on a self-organized criticality models (SOC). A relativistic test-particle simulation traces each particle’s guiding center within these configurations. Using the simulated particle-energy distributions we test our results against observations, in the framework of the collisional thick target model (CTTM) of solar hard X-ray (HXR) emission and compare our results with the current observations.

Local and regional greenhouse gas management

International Nuclear Information System (INIS)

Fleming, P.D.; Webber, P.H.

2004-01-01

This paper discusses the role of local government, working at both the local and regional level, to achieve substantial (greater than 20%) greenhouse gas emissions reductions. It identifies many different funding regimes and organisations supporting greenhouse gas emissions reductions and a lack of data with which to measure progress. The work in the East Midlands and in the City of Leicester are summarised and an evaluation of progress towards Leicester's target of 50% carbon dioxide (CO 2 ) emission reduction by 2025 based on 1990 is presented. Leicester's initiatives to reduce carbon emissions for the domestic and non-domestic sectors between 1996 and 1999 are analysed. Progress has been made in reducing the rate of rise in energy demand in Leicester and where energy efficiency activities have been concentrated, savings of 20-30% have been obtained. Significant CO 2 savings are achievable at the local and regional level, but the streamlining of support mechanisms for local authorities and a clearer national framework to support implementation are needed to enable all, rather than a few, UK local authorities to make progress

Report of the advisory group meeting on the establishment of regional ion accelerator centers and user networks

International Nuclear Information System (INIS)

1997-11-01

In this report it is shown that ion accelerators have had a tremendous economic and technological impact on most developed countries, and are beginning to have a significant impact on developing countries. Through the formation of Accelerator Centers and User Networks (which may be national, regional or inter-regional) a mechanism will be outlined by which scientists and other users from developing countries can receive the necessary training and have available the necessary accelerator facilities to use these machines for economic improvement and technological development in their countries

Nonlinear-Based MEMS Sensors and Active Switches for Gas and Acceleration Applications

KAUST Repository

Younis, Mohammad I.

2016-11-25

In this talk, we demonstrate the realization of smart sensors and actuators through the exploitation of principles of nonlinear dynamics at the micro scale. Specifically, we demonstrate combining sensing and actuation into a single device through what is called smart switches triggered by the detection of a desirable physical quantity. The concept aims to reduce the complexity of systems that rely on controllers and complex algorithms to realize on-demand trigger actions. In the first part of the talk, we discuss the category of switches triggered by the detection of gas. Toward this, electrostatically microbeams resonators are fabricated, then coated with highly absorbent polymers (MOFs), and afterward are exposed to gases. Such devices can be useful for instant alarming of toxic gases. In the second part, we demonstrate switches triggered by shock and acceleration. The concept is demonstrated on a millimeter-scale capacitive sensor. The sensor is tested using acceleration generated from shakers. Such devices can be used for the deployment of airbags in automobiles.

Development of intense high-energy noble gas ion beams from in-terminal ion injector of tandem accelerator using an ECR ion source

Energy Technology Data Exchange (ETDEWEB)

Matsuda, M., E-mail: matsuda.makoto@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Tokai Research and Development Center, 2-4 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Nakanoya, T.; Hanashima, S.; Takeuchi, S. [Japan Atomic Energy Agency (JAEA), Tokai Research and Development Center, 2-4 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1195 (Japan)

2011-10-21

An ECRIS-based heavy ion injector was constructed in the high-voltage terminal of JAEA-Tokai Tandem Accelerator to develop new beam species of highly charged noble gas ions. This work was associated with a lot of development to operate the ion source on the 20UR Pelletron high voltage terminal in high pressure SF{sub 6} gas environment. Highly charged ions of N, O, Ne, Ar, Kr and Xe have been accelerated satisfactorily. Operating data integrated during many years long beam delivery service are summarized.

Assessing electronic cigarette emissions: linking physico-chemical properties to product brand, e-liquid flavoring additives, operational voltage and user puffing patterns.

Science.gov (United States)

Zhao, Jiayuan; Nelson, Jordan; Dada, Oluwabunmi; Pyrgiotakis, Georgios; Kavouras, Ilias G; Demokritou, Philip

2018-02-01

Users of electronic cigarettes (e-cigs) are exposed to particles and other gaseous pollutants. However, major knowledge gaps on the physico-chemical properties of such exposures and contradictory data in published literature prohibit health risk assessment. Here, the effects of product brand, type, e-liquid flavoring additives, operational voltage, and user puffing patterns on emissions were systematically assessed using a recently developed, versatile, e-cig exposure generation platform and state-of-the-art analytical methods. Parameters of interest in this systematic evaluation included two brands (A and B), three flavors (tobacco, menthol, and fruit), three types of e-cigs (disposable, pre-filled, and refillable tanks), two puffing protocols (4 and 2 s/puff), and four operational voltages (2.2-5.7 V). Particles were generated at a high number concentration (10 6 -10 7 particles/cm 3 ). The particle size distribution was bi-modal (∼200 nm and 1 µm). Furthermore, organic species (humectants propylene glycol and glycerin, nicotine) that were present in e-liquid and trace metals (potassium and sodium) that were present on e-cig heating coil were also released into the emission. In addition, combustion-related byproducts, such as benzene and toluene, were also detected in the range of 100-38,000 ppbv/puff. Parametric analyzes performed in this study show the importance of e-cig brand, type, flavor additives, user puffing pattern (duration and frequency), and voltage on physico-chemical properties of emissions. This observed influence is indicative of the complexity associated with the toxicological screening of emissions from e-cigs and needs to be taken into consideration.

Murgabskaya Oblast, a promising gas region of Central Asia

Energy Technology Data Exchange (ETDEWEB)

Amanniyazov, K.N.; Abdyyev, A.A.

1981-01-01

Gas fields of the Murgabskiy region are multiple-bed. The industrial gas content is associated with the sandy-terrigenous formations of the Shatlyk productive level of the lower Goterivskiy stage. The gas formation is anticlinal, occasionally floating. A map is compiled for the dispersal of the Shatlyk level which isolates the lithological composition, thickness, zones of dispersal of sandstone, etc. A description is provided for the map plan of the Shatlyk level. Alternation of sandy-argillaceous and carbonate rocks created favorable prerequisites for the development in the deposits of the Neocomian of lithological-physical pairs of ''collectors-mantles'', the basis for trap formation in structures and zones of lithological substitution. Within the Murgabskiy region, the greatest outlook for discovering new gas fields is confined to the Shatlyk level. It is associated with the central part of the Murgabskiy Basin where major deposits have already been discovered. A group of structures in the eastern submersion of the Kopetdag trough at the junction of the Murgabskiy Basin is important. The structures at the junction of East Kopetdag and the Murgabskiy Basin may be promising. The outlook for possible gas is associated with deposits of the lower cretaceous and Sharaplinksiy level. The main task must be comprehensive in investigation of the suprasaline apt-Neocomian and Kimmeridgian-Tithonian deposits as possible multiple-bed gas and oil containing masses.

Improved plasma accelerator

Science.gov (United States)

Cheng, D. Y.

1971-01-01

Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

ELECTROMAGNETIC AND THERMAL SIMULATIONS FOR THE SWITCH REGION OF A COMPACT PROTON ACCELERATOR

International Nuclear Information System (INIS)

Wang, L; Caporaso, G J; Sullivan, J S

2007-01-01

A compact proton accelerator for medical applications is being developed at Lawrence Livermore National Laboratory. The accelerator architecture is based on the dielectric wall accelerator (DWA) concept. One critical area to consider is the switch region. Electric field simulations and thermal calculations of the switch area were performed to help determine the operating limits of rmed SiC switches. Different geometries were considered for the field simulation including the shape of the thin Indium solder meniscus between the electrodes and SiC. Electric field simulations were also utilized to demonstrate how the field stress could be reduced. Both transient and steady steady-state thermal simulations were analyzed to find the average power capability of the switches

A consumption-based, regional input-output analysis of greenhouse gas emissions and the carbon regional index

DEFF Research Database (Denmark)

Boyd, Britta; Mangalagiu, Diana; Straatman, Bas

2018-01-01

This paper presents a consumption-based method accounting for greenhouse gas emissions at regional level based on a multi-region input-output model. The method is based on regional consumption and includes imports and exports of emissions, factual emission developments, green investments as well...

Physical study of experimental fusion breeder FEB divertor

International Nuclear Information System (INIS)

Zhu Yukun; Zhou Xiaobing; Huang Jinhua; Feng Kaiming; Deng Peizhi; Huo Tiejun

1999-10-01

The physical study of FEB divertor is presented. In order to improve the impurity control and increase ion-neutral interactions in the divertor, the configuration of the divertor is optimized to be the close type in the engineering design activity compared with the open type in the early conceptual activity. The operation mode of the divertor is designed to be partial detached plasma mode under conditions of combination gas-puffing with impurity injection. The position of gas-puffing is optimized to be at the torus mid-plane with NEWT1D code from the viewpoint of impurity retention and radiation in the scrape-off layer/divertor region. Boron is chosen as the injected impurity. The effect of boron impurity injection is evaluated from the reduced heat load on the divertor target. The plasma pressure drop along the scrape-off layer/divertor region is estimated with the two-point transport model and impurity radiation model in the dynamic gas target concept. The simulation results show that the plasma pressure drop factor f p is not only related to the radiation fraction f rad but also related greatly to the stagnation point density n s

X-ray emission of the hot gas and of accelerated particles in supernova remnants

International Nuclear Information System (INIS)

Acero, F.

2008-09-01

The current observations seem to support the theory that the shock wave of supernova remnants accelerate electrons (representing about 1% of cosmic rays) of the interstellar medium up to energies of about 10 15 eV. However there is still no solid evidence that supernova remnants also accelerate protons (major component of cosmic rays). The X-ray observations of those supernova remnants with the satellite XMM-Newton can provide crucial information on the acceleration mechanisms and on this population of accelerated particles. This thesis presents the X-ray analysis of the supernova remnants RX J1713.7-3946 and SN 1006 for which it has been shown that they accelerate electrons efficiently. As a result, these objects are very good targets to compare the theoretical models of acceleration to the observation. For the first object, I constructed through new XMM-Newton observations, the first high-angular resolution mosaic of the entire supernova remnant. I then compared the X- and gamma-ray emission of this object in order to understand the nature of the gamma-ray emission. This spectral and morphological comparison allowed me to discuss the two possible origins of the gamma-ray radiation (issued by electrons or by protons). For SN 1006, I studied the density of the ambient medium in which the shock wave propagates. This density is a key parameter for the hydrodynamical evolution of the remnant and for studying a future gamma-ray emission. The study of X-ray emission of the gas heated by the shock wave allowed me to better estimate of the value of the density so far poorly constrained for this object. (author)

Contribution to the central region study of the first cyclotron of the Rhone-Alpes accelerator system

International Nuclear Information System (INIS)

Khallouf, A.

1986-01-01

Some changes seemed necessary such as the structure of the central region in order to obtain good centring and good axial and radial stabilities for the different conditions of acceleration. The most simple calculations of the center of cyclotron already developed such as the acceleration in a constant electric field, but with enough regions to obtain a good precision have been resumed. As analytic tool a computer program calculates the trajectories of a charged particle given its characteristics and the conditions of injection, and the parameters of the system of acceleration and guiding. The program calculates orbit of the particle. A criterion of judgement to permit modifications of the hypothesis leading to the solution needed to obtain good working conditions for the cyclotron has been established [fr

Laser wakefield acceleration using wire produced double density ramps

Directory of Open Access Journals (Sweden)

M. Burza

2013-01-01

Full Text Available A novel approach to implement and control electron injection into the accelerating phase of a laser wakefield accelerator is presented. It utilizes a wire, which is introduced into the flow of a supersonic gas jet creating shock waves and three regions of differing plasma electron density. If tailored appropriately, the laser plasma interaction takes place in three stages: Laser self-compression, electron injection, and acceleration in the second plasma wave period. Compared to self-injection by wave breaking of a nonlinear plasma wave in a constant density plasma, this scheme increases beam charge by up to 1 order of magnitude in the quasimonoenergetic regime. Electron acceleration in the second plasma wave period reduces electron beam divergence by ≈25%, and the localized injection at the density downramps results in spectra with less than a few percent relative spread.

A fast-acting hydrogen gas source for staged pneumatic high-speed acceleration of fusion plasma fuel pellets

International Nuclear Information System (INIS)

Andersen, S.A.; Baekmark, L.

1990-02-01

This report describes a possible design of a fast, high-temperature, arc-driven hydrogen gas source module, to be used in a scheme for multistage high-speed pneumatic acceleration of fusion plasma fuel pellets. The potential of this scheme for operating with a moderate driving pressure at long acceleration path lengths is particular attractive for accelerating fragile hydrogen isotope ice pellets. From experiments with an ethanol-based arc unit, design parameters for a propeller module were assessed, and with a barrel-mounted ethanol module staged pneumatic acceleration of a plastic dummy pellet was demonstrated. In experiments with a hydrogenbased, cryogenic arc unit in which 200 joules of electrical energy were dissipated with a power level approaching 5 MW within 30 mus, the velocity of a 23-mg plastic pellet was increased from 1.7 to 2.4 km/s. Results in terms of barrel pressure transients and arc characteristics are described. (author) 20 ills., 8 refs

Regional air quality impacts of increased natural gas production and use in Texas.

Science.gov (United States)

Pacsi, Adam P; Alhajeri, Nawaf S; Zavala-Araiza, Daniel; Webster, Mort D; Allen, David T

2013-04-02

Natural gas use in electricity generation in Texas was estimated, for gas prices ranging from $1.89 to $7.74 per MMBTU, using an optimal power flow model. Hourly estimates of electricity generation, for individual electricity generation units, from the model were used to estimate spatially resolved hourly emissions from electricity generation. Emissions from natural gas production activities in the Barnett Shale region were also estimated, with emissions scaled up or down to match demand in electricity generation as natural gas prices changed. As natural gas use increased, emissions decreased from electricity generation and increased from natural gas production. Overall, NOx and SO2 emissions decreased, while VOC emissions increased as natural gas use increased. To assess the effects of these changes in emissions on ozone and particulate matter concentrations, spatially and temporally resolved emissions were used in a month-long photochemical modeling episode. Over the month-long photochemical modeling episode, decreases in natural gas prices typical of those experienced from 2006 to 2012 led to net regional decreases in ozone (0.2-0.7 ppb) and fine particulate matter (PM) (0.1-0.7 μg/m(3)). Changes in PM were predominantly due to changes in regional PM sulfate formation. Changes in regional PM and ozone formation are primarily due to decreases in emissions from electricity generation. Increases in emissions from increased natural gas production were offset by decreasing emissions from electricity generation for all the scenarios considered.

Impact of shale gas development on regional water quality.

Science.gov (United States)

Vidic, R D; Brantley, S L; Vandenbossche, J M; Yoxtheimer, D; Abad, J D

2013-05-17

Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from environmental risks, however, especially those related to regional water quality, such as gas migration, contaminant transport through induced and natural fractures, wastewater discharge, and accidental spills. We review the current understanding of environmental issues associated with unconventional gas extraction. Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help manage these water-quality risks today and in the future.

Regional strategies for the accelerating global problem of groundwater depletion

Science.gov (United States)

Aeschbach-Hertig, Werner; Gleeson, Tom

2012-12-01

Groundwater--the world's largest freshwater resource--is critically important for irrigated agriculture and hence for global food security. Yet depletion is widespread in large groundwater systems in both semi-arid and humid regions of the world. Excessive extraction for irrigation where groundwater is slowly renewed is the main cause of the depletion, and climate change has the potential to exacerbate the problem in some regions. Globally aggregated groundwater depletion contributes to sea-level rise, and has accelerated markedly since the mid-twentieth century. But its impacts on water resources are more obvious at the regional scale, for example in agriculturally important parts of India, China and the United States. Food production in such regions can only be made sustainable in the long term if groundwater levels are stabilized. To this end, a transformation is required in how we value, manage and characterize groundwater systems. Technical approaches--such as water diversion, artificial groundwater recharge and efficient irrigation--have failed to balance regional groundwater budgets. They need to be complemented by more comprehensive strategies that are adapted to the specific social, economic, political and environmental settings of each region.

NGVLA Observations of Dense Gas Filaments in Star-Forming Regions

Science.gov (United States)

Di Francesco, James; Chen, Mike; Keown, Jared; GAS Team, KEYSTONE Team

2018-01-01

Recent observations of continuum emission from nearby star-forming regions with Herschel and JCMT have revealed that filaments are ubiquitous structures within molecular clouds. Such filaments appear to be intimately connected to star formation, with those having column densities of AV > 8 hosting the majority of prestellar cores and young protostars in clouds. Indeed, this “threshold” can be explained simply as the result of supercritical cylinder fragmentation. How specifically star-forming filaments form in molecular clouds, however, remains unclear, though gravity and turbulence are likely involved. Observations of their kinematics are needed to understand how mass flows both onto and through these filaments. We show here results from two recent surveys, the Green Bank Ammonia Survey (GAS) and the K-band Examinations of Young Stellar Object Natal Environments (KEYSTONE) that have used the Green Bank Telescope’s K-band Focal Plane Array instrument to map NH3 (1,1) emission from dense gas in nearby star-forming regions. Data from both surveys show that NH3 emission traces extremely well the high column density gas across these star-forming regions. In particular, the GAS results for NGC 1333 show NH3-based velocity gradients either predominantly parallel or perpendicular to the filament spines. Though the GAS and KEYSTONE data are vital for probing filaments, higher resolutions than possible with the GBT alone are needed to examine the kinematic patterns on the 0.1-pc scales of star-forming cores within filaments. We describe how the Next Generation Very Large Array (NGVLA) will uniquely provide the key wide-field data of high sensitivity needed to explore how ambient gas in molecular clouds forms filaments that evolve toward star formation.

High power laser exciter accelerators

International Nuclear Information System (INIS)

Martin, T.H.

1975-01-01

Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

Regional blood flow in the domestic fowl immediately following chronic acceleration

International Nuclear Information System (INIS)

Weidner, W.J.; Hoffman, L.F.; Clark, S.D.

1982-01-01

In order to examine the effects of chronic low G acceleration on blood flow distribution and cardiac output, chickens (N.10) were centrifuged at +2Gz for 30-61 d. Controls (N.12) were not centrifuged. The animals were anesthetized with sodium pentobarbital after removal from the centrifuge and surgically prepared in order to measure cardiac output and regional blood flows by the reference sample method with 85 Sr labeled microspheres (15 +/- 5 mum diam.). Both brachial arteries were cannulated to withdraw timed, paired blood samples at a known rate. The chest was opened and a cannula inserted into the left ventricle for administration of microspheres. Tissue samples were taken after completion of experimental procedures and their radioactivity was determined. The cardiac outputs in the two groups were not significantly different. Regional blood flows to the kidney, eyes, and skeletal muscle were significantly increased in the animals subjected to chronic +2Gz. While the mechanism by which these increases in blood flow occurred is not known, results indicate that chronic exposure to hyperdynamic gravitational fields can alter circulatory dynamics. We conclude that the cardiovascular system is directly involved in the process of adaptation to chronic positive acceleration

Density and impurity profile behaviours in HL-2A tokamak with different gas fuelling methods

International Nuclear Information System (INIS)

Zheng-Ying, Cui; Yan, Zhou; Wei, Li; Bei-Bin, Feng; Ping, Sun; Chun-Feng, Dong; Yi, Liu; Wen-Yu, Hong; Qing-Wei, Yang; Xuan-Tong, Ding; Xu-Ru, Duan

2009-01-01

The electron density profile peaking and the impurity accumulation in the HL-2A tokamak plasma are observed when three kinds of fuelling methods are separately used at different fuelling particle locations. The density profile becomes more peaked when the line-averaged electron density approaches the Greenwald density limit n G and, consequently, impurity accumulation is often observed. A linear increase regime in the density range n e G and a saturation regime in n e > 0.6n G are obtained. There is no significant difference in achieved density peaking factor f ne between the supersonic molecular beam injection (SMBI) and gas puffing into the plasma main chamber. However, the achieved f ne is relatively low, in particular, in the case of density below 0.7n G , when the working gas is puffed into the divertor chamber. A discharge with a density as high as 1.2n G , i.e. n e = 1.2n G , can be achieved by SMBI just after siliconization as a wall conditioning. The metallic impurities, such as iron and chromium, also increase remarkably when the impurity accumulation happens. The mechanism behind the density peaking and impurity accumulation is studied by investigating both the density peaking factor versus the effective collisionality and the radiation peaking versus density peaking. (fluids, plasmas and electric discharges)

The problem of formation of strategic oil-gas research alliance's in the Caspian region

International Nuclear Information System (INIS)

Kovalenko, V.S.; Silantiev, I.D.; Skorobogatov, V.A.

2002-01-01

Full text : Common information is given here concerning the Caspian region that is located in the juncture zone of two regions : European and Western Asian. While the European region is a great centre of gas consumption, the Western Asian region contains the largest gas accumulation. Gas supply from Iran, Iraq, Turkmenia in the western direction requires strategic alliances in development of hydrocarbon potential. Also project investments on PSA base are more developed. Russia uses PSA mechanisms and strategic alliance formation. Reasons for strategic alliance formation for every company are widely described. Analysis of seismic data proves existence of anomalies of hydrocarbon pool type to filter the prospect portfolio, geological information complex analysis and preparation materials for oil and gas atlas formation. Peculiarity of Caspian region determine the necessing of international strategic alliance for decision infrastructure formation and ecosystem conservation

Simulation study of the sub-terawatt laser wakefield acceleration operated in self-modulated regime

Science.gov (United States)

Hsieh, C.-Y.; Lin, M.-W.; Chen, S.-H.

2018-02-01

Laser wakefield acceleration (LWFA) can be accomplished by introducing a sub-terawatt (TW) laser pulse into a thin, high-density gas target. In this way, the self-focusing effect and the self-modulation that happened on the laser pulse produce a greatly enhanced laser peak intensity that can drive a nonlinear plasma wave to accelerate electrons. A particle-in-cell model is developed to study sub-TW LWFA when a 0.6-TW laser pulse interacts with a dense hydrogen plasma. Gas targets having a Gaussian density profile or a flat-top distribution are defined for investigating the properties of sub-TW LWFA when conducting with a gas jet or a gas cell. In addition to using 800-nm laser pulses, simulations are performed with 1030-nm laser pulses, as they represent a viable approach to realize the sub-TW LWFA driven by high-frequency, diode-pumped laser systems. The peak density which allows the laser peak power PL˜2 Pc r of self-focusing critical power is favourable for conducting sub-TW LWFA. Otherwise, an excessively high peak density can induce an undesired filament effect which rapidly disintegrates the laser field envelope and violates the process of plasma wave excitation. The plateau region of a flat-top density distribution allows the self-focusing and the self-modulation of the laser pulse to develop, from which well-established plasma bubbles can be produced to accelerate electrons. The process of electron injection is complicated in such high-density plasma conditions; however, increasing the length of the plateau region represents a straightforward method to realize the injection and acceleration of electrons within the first bubble, such that an improved LWFA performance can be accomplished.

Technical specification for a 25 MV tandem electrostatic accelerator

International Nuclear Information System (INIS)

Jones, C.M.; Biggerstaff, J.A.; Blair, J.K.; Ball, J.B.; Larson, J.D.; Martin, J.A.; McConnell, J.W.; Milner, W.T.; Murray, J.A.; Ziegler, N.F.

1975-08-01

Specifications are given for an accelerator system to consist of a 25 MV tandem electrostatic accelerator and specified ancillary equipment, including an injector, a beam transport system, a vacuum system, a control system, and a system for storage of the insulating gas and transport of the gas to and from the accelerator. The insulating gas shall be SF 6 . The tandem electrostatic accelerator shall be vertical in orientation and of folded construction, and shall be installed in a new structure adjacent to the Oak Ridge Isochronous Cyclotron. (auth)

Impacts of Marcellus Shale Natural Gas Production on Regional Air Quality

Science.gov (United States)

Swarthout, R.; Russo, R. S.; Zhou, Y.; Mitchell, B.; Miller, B.; Lipsky, E. M.; Sive, B. C.

2012-12-01

Natural gas is a clean burning alternative to other fossil fuels, producing lower carbon dioxide (CO2) emissions during combustion. Gas deposits located within shale rock or tight sand formations are difficult to access using conventional drilling techniques. However, horizontal drilling coupled with hydraulic fracturing is now widely used to enhance natural gas extraction. Potential environmental impacts of these practices are currently being assessed because of the rapid expansion of natural gas production in the U.S. Natural gas production has contributed to the deterioration of air quality in several regions, such as in Wyoming and Utah, that were near or downwind of natural gas basins. We conducted a field campaign in southwestern Pennsylvania on 16-18 June 2012 to investigate the impact of gas production operations in the Marcellus Shale on regional air quality. A total of 235 whole air samples were collected in 2-liter electropolished stainless- steel canisters throughout southwestern Pennsylvania in a regular grid pattern that covered an area of approximately 8500 square km. Day and night samples were collected at each grid point and additional samples were collected near active wells, flaring wells, fluid retention reservoirs, transmission pipelines, and a processing plant to assess the influence of different stages of the gas production operation on emissions. The samples were analyzed at Appalachian State University for methane (CH4), CO2, C2-C10 nonmethane hydrocarbons (NMHCs), C1-C2 halocarbons, C1-C5 alkyl nitrates and selected reduced sulfur compounds. In-situ measurements of ozone (O3), CH4, CO2, nitric oxide (NO), total reactive nitrogen (NOy), formaldehyde (HCHO), and a range of volatile organic compounds (VOCs) were carried out at an upwind site and a site near active gas wells using a mobile lab. Emissions associated with gas production were observed throughout the study region. Elevated mixing ratios of CH4 and CO2 were observed in the

Profile Monitors Based on Residual Gas Interaction

CERN Document Server

Forck, P; Giacomini, T; Peters, A

2005-01-01

The precise determination of transverse beam profiles at high current hadron accelerators has to be performed non-interceptingly. Two methods will be discussed based on the excitation of the residual gas molecules by the beam particles: Firstly, by beam induced fluorescence (BIF) light is emitted from the residual gas molecules and is observed with an image intensified CCD camera. At most laboratories N2 gas is inserted, which has a large cross section for emission in the blue wave length region. Secondly, a larger signal strength is achieved by detecting the ionization products in an Ionization Profile Monitor (IPM). By applying an electric field all ionization products are accelerated toward a spatial resolving Micro-Channel Plate. The signal read-out can either be performed by observing the light from a phosphor screen behind the MCP or electronically by a wire array. Methods to achieve a high spatial resolution and a fast turn-by-turn readout capability are discussed. Even though various approaches at dif...

A Tale of Two Regions: Landscape Ecological Planning for Shale Gas Energy Futures

Science.gov (United States)

Murtha, T., Jr.; Schroth, O.; Orland, B.; Goldberg, L.; Mazurczyk, T.

2015-12-01

As we increasingly embrace deep shale gas deposits to meet global energy demands new and dispersed local and regional policy and planning challenges emerge. Even in regions with long histories of energy extraction, such as coal, shale gas and the infrastructure needed to produce the gas and transport it to market offers uniquely complex transformations in land use and landcover not previously experienced. These transformations are fast paced, dispersed and can overwhelm local and regional planning and regulatory processes. Coupled to these transformations is a structural confounding factor. While extraction and testing are carried out locally, regulation and decision-making is multilayered, often influenced by national and international factors. Using a geodesign framework, this paper applies a set of geospatial landscape ecological planning tools in two shale gas settings. First, we describe and detail a series of ongoing studies and tools that we have developed for communities in the Marcellus Shale region of the eastern United States, specifically the northern tier of Pennsylvania. Second, we apply a subset of these tools to potential gas development areas of the Fylde region in Lancashire, United Kingdom. For the past five years we have tested, applied and refined a set of place based and data driven geospatial models for forecasting, envisioning, analyzing and evaluating shale gas activities in northern Pennsylvania. These models are continuously compared to important landscape ecological planning challenges and priorities in the region, e.g. visual and cultural resource preservation. Adapting and applying these tools to a different landscape allow us to not only isolate and define important regulatory and policy exigencies in each specific setting, but also to develop and refine these models for broader application. As we continue to explore increasingly complex energy solutions globally, we need an equally complex comparative set of landscape ecological

Analysis of GRI North American Regional Gas Supply-Demand Model

International Nuclear Information System (INIS)

Nesbitt, D.M.; Singh, J.; Pine, G.D.; Kline, D.; Barron, M.; Cheung, P.D.

1989-01-01

This paper summarizes the results from the GRI North American Regional Gas Supply-Demand Model using the four scenarios defined for the Energy Modeling Forum Number 9 (EMF-9) described in EMF-9 Working Paper 9.4 (1987). The analysis is designed both to showcase the GRI North American Regional model as well as to infer meaningful results about the North American natural gas system. The focus of the analysis is not R ampersand D per se; R ampersand D analysis using the model is conducted regularly by GRI and described elsewhere. Rather, the objective is to analyze some of the major uncertainties in the North American gas market, uncertainties that potentially affect all players including GRI. In particular, the authors seek to quantify the overall economic environment in which production, transmission, distribution, consumption, and R ampersand D decisions will be made and how different that overall environment might be under alternative assumptions. An attendant objective of this analysis has been to enlist economists from a range of organizations (producers, regulators, GRI, and consultants) to carefully scrutinize the GRI North American Regional model and results. In particular, the coauthors were assembled from diverse organizations to review and evaluate model outputs, applying their particular experience and perspective. The four EMF-9 scenarios upon which this paper is based are described in detail later in this document. Briefly, scenario one represents a world with a surfeit of gas and a relatively high oil price projection; scenario two considers a lower oil price forecast; scenario three assumes a pessimistic outlook for the gas resource base with the same oil prices as scenario one; and scenario four examines a higher level of demand for gas in the North American gas market. An important objective of this analysis is to illustrate the predictive power of multi-scenario comparisons (as contrasted with detailed analysis of any individual scenario)

Analysis on natural gas geo-politics in Central Asia-Russia region

Energy Technology Data Exchange (ETDEWEB)

Feng, Dan

2010-09-15

In the year of 2009, some events happened in Central Asia-Russia Region. The transit countries of Nabucco pipeline signed the agreement and the project received considerable progress. The China-Turkmenistan pipeline achieved the completion of ventilation. All these could be landmarks in Central Asia-Russia's geo-political situation. Diversification strategy of gas imports in Europe and diversification strategy of export in Central Asia have been effectively promoted, and the relationship between China and Central Asia becomes closer. Now, the new supply pattern of the region is coming into being and the nature gas geo-political situation in the region is undergoing profound changes.

The Kaarstoe gas terminal during operation - regional economic effects

International Nuclear Information System (INIS)

Wiig, W.; Kristiansen, F.

1995-02-01

In the period 1981-1989 a comprehensive study was made of the impact on society of the establishment of Statoil's gas terminal at Kaarstoe, Norway. Some of this work is updated in the present report. The organization at Kaarstoe is Statoil's transport division for gas (GASS-T) and is described in Chapter 2. A survey is given in Chapter 3 of how the employees are associated with the local community, their distribution in age, sex and type of job. Chapter 4 treats the importance for the Haugesund region of the company's purchasing in the area, in particular from suppliers within the Tysvaer municipality. The development of the structure of industry in Tysvaer and the employment situation are described in Chapter 5. Population trends and housebuilding in Tysvaer are described in Chapter 6 and the impact of GASS-T on the municipal economy is described in Chapter 7. Finally, Chapter 8 discusses whether what is learned from Kaarstoe can be transferred to other regions where gas terminals have been established. 14 refs., 24 figs., 12 tabs

Experimental investigation of density behaviors in front of the lower hybrid launcher in experimental advanced superconducting tokamak

International Nuclear Information System (INIS)

Zhang, L.; Ding, B. J.; Li, M. H.; Kong, E. H.; Wei, W.; Liu, F. K.; Shan, J. F.; Wu, Z. G.; Zhu, L.; Ma, W. D.; Tong, Y. Y.; Li, Y. C.; Wang, M.; Zhao, L. M.; Hu, H. C.; Liu, L.

2013-01-01

A triple Langmuir probe is mounted on the top of the Lower Hybrid (LH) antenna to measure the electron density near the LH grills in Experimental Advanced Superconducting Tokamak. In this work, the LH power density ranges from 2.3 MWm −2 to 10.3 MWm −2 and the rate of puffing gas varies from 1.7 × 10 20 el/s to 14 × 10 20 el/s. The relation between the edge density (from 0.3 × n e-cutoff to 20 × n e-cutoff , where n e-cutoff is the cutoff density, n e-cutoff = 0.74 × 10 17 m −3 for 2.45 GHz lower hybrid current drive) near the LH grill and the LH power reflection coefficients is investigated. The factors, including the gap between the LH grills and the last closed magnetic flux surface, line-averaged density, LH power, edge safety factor, and gas puffing, are analyzed. The experiments show that injection of LH power is beneficial for increasing edge density. Gas puffing is beneficial for increasing grill density but excess gas puffing is unfavorable for coupling and current drive

Energy and greenhouse gas profile of the Nouvelle Aquitaine region. Release 2017

International Nuclear Information System (INIS)

Rousset, Alain; Poitevin, Lionel; Loeb, Amandine; Philippot, Herve; Rebouillat, Lea; Jacquelin, Antoine

2017-06-01

This publication first proposes graphs and comments characterising final energy consumption of the Nouvelle Aquitaine region: regional situation in 2015 (analysis per sector and per energy), primary resources, social-economic analysis (energy bill, level of energy poverty, burden due to old housing and commuting for households), evolution of energy consumption between 2005 and 2015 (per sector, per source of energy, evolution of energy intensity and of the energy bill). The next part addresses greenhouse gas emissions: regional situation in 2015 (distribution in terms of emission type and per gas), evolutions between 1990 and 2015, evolutions per sector. The third part addresses renewable energies: regional situation for the different types of renewable energy, comparison with final energy consumption, comparison with national data, production evolutions, focus per sector (wood and wood by-products, heat pumps in the housing sector, urban waste valorisation units, biogas valorisation, bio-fuels, wind energy, hydroelectricity, solar photovoltaic). The last part recalls national objectives related to energy, to greenhouse gas emissions for France and for the region, in relationship with the law on energy transition and for a green growth

Integrated approach to natural gas utilization in the Asia Pacific region

International Nuclear Information System (INIS)

Hovdestad, W.R.; Egbogah, E.O.

1995-01-01

The rapidly expanding economies in the Pacific Rim have placed increasing demands upon indigenous natural gas supplies in South East Asia and Australia. Competing demands include exports of liquefied natural gas (LNG), domestic consumption, and potential use for enhanced oil recovery (EOR) to extend the useful life of maturing oil fields. An additional competing demand for gas exports may emerge as the interstate pipeline grid is expanded. An integrated approach incorporating the evolving nature of gas demands and discrete physical supplies would provide a means to mitigate against potential mismatching of supply and demand. The consideration of the evolving nature of gas demands could promote economically beneficial changes to gas field development. The development of high carbon dioxide (CO 2 ) content gas fields has been slowed by the lack of a market for CO 2 . Utilization of by-product CO 2 for EOR could improve development economics, thus facilitating earlier development of gas supplies to satisfy gas demands including domestic use and LNG exports. End users would also benefit from the assurance that gas supplies would become available as needed. The maturity and increasingly complex natural gas industry in the Asia Pacific Region has led to a qualitative change. The model of single projects to satisfy single markets is no longer valid. The current environment is more dynamic, creating the need to anticipate changes to market demands and to find value-added markets for by-products. The integrated approach to gas utilization discussed in this paper presents a new model more appropriate to the gas industry existing today in the Asia Pacific Region. This approach is particularly significant to widely discussed proposals for an Asia Pacific energy grid extending to Australia

EMC3-Eirene simulations of gas puff effects on edge density and ICRF coupling in ASDEX Upgrade

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei; Noterdaeme, Jean-Marie [Max Planck Institute for Plasma Physics, Garching (Germany); University of Ghent, Ghent (Belgium); Coster, David; Lunt, Tilmann; Bobkov, Volodymyr; Feng, Yuehe [Max Planck Institute for Plasma Physics, Garching (Germany); Collaboration: ASDEX Upgrade team

2015-05-01

Ion cyclotron range of frequency (ICRF) heating relies on the Fast Wave (FW) to transport the power from the edge (the antenna) to the plasma center. Since the FW is evanescent below a critical density (typically in the 10{sup 18} m{sup -3} range), the wave does not propagate in the region where the density is below this value in the very edge of the plasma. The coupling depends strongly on the width of this region. The distance between the ICRF antenna and the FW cut-off layer can be made smaller by increasing the edge density in front of the ICRF antenna. Previous experiments in many tokamaks and preliminary simulation results for AUG and JET with EDGE2D-EIRENE show that the edge density could indeed be increased with gas puffing at the top of the vessel or in the midplane. But the 2D code cannot quantitatively reproduce the experimental results, mainly due to the assumptions of toroidal axisymmetry. EMC3-EIRENE is a 3D Edge Monte Carlo plasma fluid transport code. By including the toroidal nonaxisymmetric plasma facing components and 3D positions of gas valves in the code, the simulations can be made more realistic. We will show first simulation results of the code and a comparison to experiments.

Ion beam dynamics in the acceleration region of the Vincy Cyclotron

International Nuclear Information System (INIS)

Tomic, S.; Samsonov, E.

1998-01-01

Modern concept of heavy ion cyclotrons assumes a tendency of decreasing the gaps between magnet poles, enabling better efficiency of the magnetic field circuit. This restricts possible solutions of acceleration structure and imposes the necessity of installing the dees in valleys of magnetic structures. This approach, which is accepted in the VINCY Cyclotron, requires a detailed study of the ion beam dynamics in the acceleration region. Consequently, we analyzed ion beams with eta = 1,05 and 0.25 in radial and axial phase space. Also, the energy spread in emittances and the influence of the first harmonic of the magnetic field on the radial betatron oscillations are discussed. The transformation of coherent into incoherent radial oscillations as well as the effect to radial off-centering on the beam vertical size at Walkinshaw resonance location, is pointed out (author)

Automated-process gas-chromatograph system for use in accelerated corrosion testing of HTGR core-support posts

International Nuclear Information System (INIS)

Harper, R.E.; Herndon, P.G.

1982-01-01

An automated-process gas chromatograph is the heart of a gaseous-impurities-analysis system developed for the Oak Ridge National Laboratory Core Support Performance Test, at which graphite core-support posts for high-temperature gas-cooled fission reactors are being subjected to accelerated corrosion tests under tightly controlled conditions of atmosphere and temperature. Realistic estimation of in-core corrosion rates is critically dependent upon the accurate measurement of low concentrations of CO, CO 2 , CH 4 , H 2 , and O 2 in the predominantly helium atmosphere. In addition, the capital and labor investment associated with each test puts a premium upon the reliability of the analytical system, as excessive downtime or failure to obtain accurate data would result in unacceptable costs and schedule delays. After an extensive survey of available measurement techniques, gas chromatography was chosen for reasons of accuracy, flexibility, good-performance record, and cost

Infrared video based gas leak detection method using modified FAST features

Science.gov (United States)

Wang, Min; Hong, Hanyu; Huang, Likun

2018-03-01

In order to detect the invisible leaking gas that is usually dangerous and easily leads to fire or explosion in time, many new technologies have arisen in the recent years, among which the infrared video based gas leak detection is widely recognized as a viable tool. However, all the moving regions of a video frame can be detected as leaking gas regions by the existing infrared video based gas leak detection methods, without discriminating the property of each detected region, e.g., a walking person in a video frame may be also detected as gas by the current gas leak detection methods.To solve this problem, we propose a novel infrared video based gas leak detection method in this paper, which is able to effectively suppress strong motion disturbances.Firstly, the Gaussian mixture model(GMM) is used to establish the background model.Then due to the observation that the shapes of gas regions are different from most rigid moving objects, we modify the Features From Accelerated Segment Test (FAST) algorithm and use the modified FAST (mFAST) features to describe each connected component. In view of the fact that the statistical property of the mFAST features extracted from gas regions is different from that of other motion regions, we propose the Pixel-Per-Points (PPP) condition to further select candidate connected components.Experimental results show that the algorithm is able to effectively suppress most strong motion disturbances and achieve real-time leaking gas detection.

Kinetic modeling of particle acceleration in a solar null point reconnection region

DEFF Research Database (Denmark)

Baumann, Gisela; Haugbølle, Troels; Nordlund, Åke

2013-01-01

The primary focus of this paper is on the particle acceleration mechanism in solar coronal 3D reconnection null-point regions. Starting from a potential field extrapolation of a SOHO magnetogram taken on 2002 November 16, we first performed MHD simulations with horizontal motions observed by SOHO...... particles and 3.5 billion grid cells of size 17.5\\,km --- these simulations offer a new opportunity to study particle acceleration in solar-like settings....... applied to the photospheric boundary of the computational box. After a build-up of electric current in the fan-plane of the null-point, a sub-section of the evolved MHD data was used as initial and boundary conditions for a kinetic particle-in-cell model of the plasma. We find that sub...

Cluster observations of particle acceleration up to supra-thermal energies in the cusp region related to low-frequency wave activity – possible implications for the substorm initiation process

Czech Academy of Sciences Publication Activity Database

Vogiatzis, I. I.; Sarris, T. E.; Sarris, E. T.; Santolík, Ondřej; Dandouras, I.; Robert, P.; Fritz, T. A.; Zong, Q.-G.; Zhang, H.

2008-01-01

Roč. 26, č. 3 (2008), s. 653-669 ISSN 0992-7689 R&D Projects: GA AV ČR IAA301120601 Grant - others:INTAS(XE) 03-51-4132; NASA Goddard Space Flight Center(US) NNX07AI24G; NASA Goddard Space Flight Center(US) NNG04GB98G; NSF(US) 0307319 Institutional research plan: CEZ:AV0Z30420517 Keywords : particle acceleration * cusp region * substorm initiation process Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.660, year: 2008 http://www.ann-geophys.net/26/1665/2008/

Augment-type two stage accelerator

International Nuclear Information System (INIS)

Ogino, Mutsuo; Azuma, Kingo.

1995-01-01

When a flying body accelerated by a gas gun at a first stage enters into an augment rail passing through an introduction tube, an ignition capacitor for initial plasmas is turned ON to apply a voltage between the augment rails. Subsequently, the accelerating gas present behind the flying body is formed into plasmas by a laser, to flow electric current from one of the inner augment rails → plasma armature → the other of the inner augment rails, and additionally accelerate the flying body by Lorentz force formed in this case. Since the plasmas are maintained in a state of higher density than the plasmas obtained by using all of the augment rails, the ignition capacitor for initial plasmas in switched to a power source. As a result, it is possible to flow the maximum current before the plasmas expand, and a large accelerating force and a high magnetic flux density are attained, to improve acceleration performance of the flying body. (N.H.)

Deliverability and regional pricing in U.S. natural gas markets

International Nuclear Information System (INIS)

Brown, Stephen P.A.; Yuecel, Mine K.

2008-01-01

During the 1980s and early 90s, interstate natural gas markets in the United States made a transition away from the regulation that characterized the previous three decades. With abundant supplies and plentiful pipeline capacity, a new order emerged in which freer markets and arbitrage closely linked natural gas price movements throughout the country. After the mid-1990s, however, U.S. natural gas markets tightened and some pipelines were pushed to capacity. We look for the pricing effects of limited arbitrage through causality testing between prices at nodes on the U.S. natural gas transportation system and interchange prices at regional nodes on North American electricity grids. Our tests do reveal limited arbitrage, which is indicative of bottlenecks in the U.S. natural gas pipeline system. (author)

Converging-barrel plasma accelerator

International Nuclear Information System (INIS)

Paine, T.O.

1971-01-01

The invention comprises a device for generating and accelerating plasma to extremely high velocity, while focusing the plasma to a decreasing cross section for attaining a very dense high-velocity plasma burst capable of causing nuclear fusion reactions. A converging coaxial accelerator-electrode configuration is employed with ''high-pressure'' gas injection in controlled amounts to achieve acceleration by deflagration and focusing by the shaped electromagnetic fields. (U.S.)

Natural Resources Investment of Oil and Gas and Regional Development Impact on Community Empowerment

Directory of Open Access Journals (Sweden)

Ridwan Nyak Baik

2015-06-01

Full Text Available This study was done in Bekasi district, at West Java, Indonesia, with the aims to analyze the management of upstream activities (exploration and production of oil and gas industry and its impact on improving the quality of infrastructure, the equal benefits proportion for the corporation, local government and society, and CSR programs that would affect the community empowerment. The analysis would be calculated based on the per capita income, the number of medical personals, and the number of teachers. Based on that calculation, this study analyzed the impact of oil and gas activities to the regional development of the area under this study. Analysis of regional development was calculated through number of industry in the area, the economic growth, and local government revenue that affects community empowerment in Bekasi.Analyzed by structural equation modeling (SEM, the results showed that: (1 management of upstream oil and gas activities in this area have a positive influence, but no significant effect on community empowerment; (2 management of upstream oil and gas activities have a significant positive impact on regional development; (3 regional development has a significant positive impact on community empowerment; (4 management of upstream oil and gas activities have a greater positive influence towards community empowerment through regional development, because of the multiplier effect of the development of the region.

Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts.

Science.gov (United States)

McKain, Kathryn; Down, Adrian; Raciti, Steve M; Budney, John; Hutyra, Lucy R; Floerchinger, Cody; Herndon, Scott C; Nehrkorn, Thomas; Zahniser, Mark S; Jackson, Robert B; Phillips, Nathan; Wofsy, Steven C

2015-02-17

Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas emission rates for 1 y in the urban region of Boston, using a comprehensive atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission flux, 18.5 ± 3.7 (95% confidence interval) g CH4 ⋅ m(-2) ⋅ y(-1). Simultaneous observations of atmospheric ethane, compared with the ethane-to-methane ratio in the pipeline gas delivered to the region, demonstrate that natural gas accounted for ∼ 60-100% of methane emissions, depending on season. Using government statistics and geospatial data on natural gas use, we find the average fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end use, was 2.7 ± 0.6% in the Boston urban region, with little seasonal variability. This fraction is notably higher than the 1.1% implied by the most closely comparable emission inventory.

The Effect of Moisture Content of Maize Grits on Physicochemical Properties of Its Puffed Food Products Properties of Its Puffed Food Products

Directory of Open Access Journals (Sweden)

S. Sharifi

2016-02-01

Full Text Available In this study the effect of different levels of moisture content of maize grits (10, 13, 16 and 19% as an attribute of physicochemical properties of extruder-derived puffed products, was investigated. The results showed that with increasing maize grits' moisture content, water absorption index (WAI and water solubility index (WSI were decreased. Moreover, with changing in feed moisture content from 10 to 16%, the volume and sectional expansion index (SEI increased but further increase of moisture content to 19% caused a reduction in these parameters. The textural tests also revealed that with increase in moisture content, the compression energy (Nmm, maximum force (N and time to achieve the first major peak (s were increased but the number of peaks was decreased. With increase in the moisture content, specific mechanical energy (SME was decreased, due probably to the reduction in the viscosity of melt. With increase in the moisture content the L and b values were increased but the value of the samples were decreased due to the reduction of Maillard reaction rate. Our data confirms that the moisture content of maize grits may play an important role in the quality of produced extruded snacks and a high quality product can be achieved by optimizing this parameter. In this research, the maximum volume of the extruder product was obtained in 16% of moisture level.

Collective acceleration investigations with the ionization front accelerator

International Nuclear Information System (INIS)

Olson, C.L.; Poukey, J.W.; VanDevender, J.P.; Owyoung, A.; Pearlman, J.S.

1977-01-01

Part I of a three part program to demonstrate feasibility of the Ionization Front Accelerator (IFA) has been completed and is successful. Experiments describing intense relativistic electron beam (IREB) propagation in Cs are reported. The threshold pressure for electron beam ionization of Cs is found to agree with earlier theoretical predictions. These results experimentally establish Cs as a feasible working gas for the IFA. Numerical simulation results are also reported which demonstrate controlled potential well motion and collective ion acceleration with the IFA

Empirical evaluation of the radiative cooling coefficient for krypton gas in the FTU plasma

International Nuclear Information System (INIS)

Fournier, K.B.; Pacella, D.; Mazzitelli, G.; Stutman, D.; Soukanovskii, V.; Goldstein, W.H.

1997-01-01

For future fusion reactors, a careful balance must be achieved between the cooling of the outer plasma via impurity radiation and the deleterious effects of inevitable core penetration by impurity ions. We have injected krypton gas into the Frascati Tokamak Upgrade (FTU) plasma. The measured visible bremsstrahlung and bolometric signals from krypton have been inverted and the resulting radial impurity density profile and power loss profile for krypton gas are extracted. Using the measured electron density and temperature profiles, the radiative cooling coefficient for krypton is derived. The level of intrinsic impurities (Mo, Cr, Mn and Fe) in the plasma during the krypton puffing is monitored with a VUV SPRED spectrometer. Models for krypton emissivity from the literature are compared to our measured results. 7 figs

Conceptual design study of high temperature gas-cooled reactor for plutonium incineration

International Nuclear Information System (INIS)

Goto, Minoru

2013-01-01

JAEA has started a conceptual design study of a Pu burner HTGR, which is called CBHTR (Clean Burn High Temperature gas-cooled Reactor). CBHTR’s fuel is TRISO-coated fuel particle with PuO 2 -YSZ (Yttria- Stabilized Zirconia) kernel, which increase proliferation resistance, safety of geological disposal, and Pu incineration. CBHTR can decrease Puf ratio from 60% to 20% with 520 GWd/t. In the future, 15% of electricity capacity is employed by 7 of CBHTRs and 59 of U-HTRs. JAEA has a R and D plan of manufacturing technology of TRISO-coated fuel with PuO 2 -YSZ kernel

Acceleration of plasma into vacuum

Energy Technology Data Exchange (ETDEWEB)

Marshall, John [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

1958-07-01

The first part of this paper is a discussion of the magnetic acceleration of plasma. The second part contains a description of some experiments which have been performed. In the work reported the intention is: 1. To produce a burst of gas in vacuo; 2. To ionize the gas and heat it to such an extent that it becomes a good electrical conductor. 3. To accelerate the plasma thus produced into vacuum by the use of external time-varying magnetic fields.

Gas Regional Initiative. North West Regional Energy Market. Transmission Transparency Project. First Implementation Report

International Nuclear Information System (INIS)

2008-07-01

The purpose of this report is to comment on the implementation of the TSO Transmission Transparency Project. In December 2007 sixteen TSOs presented a project plan which committed them to publishing information on capacity availability and gas flows at crossborder interconnection points in the North-West gas region. The data types to be published were agreed between TSOs and network users. It was agreed that TSOs would release new information on capacity and actual gas flows at crossborder interconnection points. The TSOs have committed to publishing the agreed information by three project milestones May, September or December 2008. At the end of May 2008 the TSOs submitted initial data to Ofgem (Office of the Gas and Electricity Markets) on implementation. This report presents the data submitted by the TSOs, provides comment on implementation progress and explains the next steps. This report does not approve or guarantee the accuracy of the data submitted by TSOs

Characterization of a plasma produced using a high power laser with a gas puff target for x-ray laser experiments

International Nuclear Information System (INIS)

Fiedorowicz, H.; Bartnik, A.; Gac, K.; Parys, P.; Szczurek, M.; Tyl, J.

1995-01-01

A high temperature, high density plasma can be produced by using a nanosecond, high-power laser with a gas puff target. The gas puff target is formed by puffing a small amount of gas from a high-pressure reservoir through a nozzle into a vacuum chamber. In this paper we present the gas puff target specially designed for x-ray laser experiments. The solenoid valve with the nozzle in the form of a slit 0.3-mm wide and up to 40-mm long, allows to form an elongated gas puff suitable for the creation of an x-ray laser active medium by its perpendicular irradiation with the use of a laser beam focused to a line. Preliminary results of the experiments on the laser irradiation of the gas puff targets, produced by the new valve, show that hot plasma suitable for x-ray lasers is created

Plasma acceleration in a wave with varying frequency

International Nuclear Information System (INIS)

Petrzilka, V.A.

1978-01-01

The averaged velocity of a test particle and the averaged velocity of a plasma in an electromagnetic wave packet with varying frequency (e.g., a radiation pulse from pulsar) is derived. The total momentum left by the wave packet in regions of plasma inhomogeneity is found. In case the plasma concentration is changing due to ionization the plasma may be accelerated parallelly or antiparallelly to the direction of the wave packet propagation which is relevant for a laser induced breakdown in gas. (author)

H-modes studies in PDX

International Nuclear Information System (INIS)

Fonck, R.J.; Beirsdorfer, P.; Bell, M.

1984-07-01

A regime of enhanced energy confinement during neutral beam heating has been obtained routinely in the PDX tokamak after modifications to form a closed divertor geometry. Plasma density profiles were broad and the electron temperature at the plasma edge reached values of approx. 400 eV in the H-mode phase of a discharge. A comparison of closed divertor discharges with moderate and intense gas puffing indicates that a requirement for obtaining high confinement times is the localization of the plasma fueling source in the divertor throat region. While high confinement was attained at moderate injected powers (P/sub INJ/ less than or equal to 3 MW), confinement was degraded at higher powers due to both increased edge instabilities and, especially, the intense gas puffing needed to prevent disruptions. Initial results with a particle scoop limiter indicate high particle confinement times and energy confinement times approaching those of diverted H-mode plasmas

Decadal Trends and Variability of Tropospheric Ozone over Oil and Gas Regions over 2005 - 2015

Science.gov (United States)

Zhou, Y.; Mao, H.; Sive, B. C.

2017-12-01

Tropospheric ozone (O3), which is produced largely by photochemical oxidation of nitrogen oxides (NOx) and volatile organic compounds, is a serious and ubiquitous air pollutant with strong negative health effects. Recent technological innovations such as horizontal drilling and hydraulic fracturing have accelerated oil and natural gas production in the U.S. since 2005. The additional input of O3 precursors from expanding natural gas production might prolong the effort to comply the current O3 standard (70 ppbv). The objective of this study is to investigate the impact of oil and gas extractions on variability and long term trends of O3 in the intermountain west under varying meteorological conditions. We investigated long-term O3 trends at 13 rural sites, which were within 100 km of the shale play in the U.S. intermountain west. Significant decreasing trends (-0.35 - -3.38 ppbv yr-1) were found in seasonal O3 design values at six sites in spring, summer, or fall, while no trends were found in wintertime O3 at any sites. Wintertime O3 at each site showed strong and consistent interannual variation over 2006 - 2015, and was negatively correlated with the Arctic Oscillation (AO) Index. The negative correlation was a result of multiple factors, such as in situ O3 photochemical production, stratospheric intrusion, and transport from the Arctic and California. In summer, wildfire emissions were the dominate driver to the interannual variations of high percentiles O3 at each site, while meteorological conditions (i.e., temperature and relative humidity) determined the interannual variations of low percentiles O3. Box model simulations indicated that O3 production rates were 31.51 ppbv h-1 over winters of 2012 - 2014 and 32.12 ppbv h-1 in summer 2014 around shale gas extraction regions.

Accelerator mass spectrometry of heavy elements: /sup 36/Cl to /sup 205/Pb

Energy Technology Data Exchange (ETDEWEB)

Henning, W

1987-08-25

Measurements are discussed in which the technique of accelerator mass spectrometry was applied to problems involving heavy radioisotopes. These measurements, which depend on the ion energies that can be reached with the new heavy-ion accelerator facilities, were performed at the Argonne tandem linac accelerator system (ATLAS) and at the UNILAC accelerator at GSI. The topics include a discussion of measurements of long nuclear lifetimes, of radioisotope detection of interest to solar neutrino experiments, and of a determination of the /sup 41/Ca concentration in natural samples of terrestrial origin by making use of isotopic pre-enrichment in an isotope separator. A long-known method of isobar separation, employing a gas-filled magnetic field region, has been revived for some of these measurements and its characteristics and advantages are briefly reviewed.

Increase in the Acceleration Efficiency of Solids in a Hybrid Coaxial Magnetoplasma Accelerator

Science.gov (United States)

Gerasimov, D. Yu.; Sivkov, A. A.

2018-01-01

It is shown that in a hybrid coaxial magnetoplasma accelerator with a channel length of 350 mm and a diameter of 23 mm, the acceleration velocity and the energy conversion efficiency increase as the length of the plasma structure formation channel filled with a gas-generating material decreases from 17 to 9 mm. It is found that it is reasonable to use paraffin as the gas-generating material as it has a less significant deionizing effect on the high-current arc discharge and hence causes a less significant decrease in the discharge current intensity and an increase in conductive and inductive electrodynamic forces.

Gas injection in EBT-S for assessment of particle loading effects of neutral beam injection

International Nuclear Information System (INIS)

Carpenter, K.H.; Glowienka, J.C.

1979-01-01

Experiments have begun to examine the physics of neutral beam injection on EBT-S. Preliminary experiments have been limited to a calibrated gas puffing experiment which simulates the effects of a pulsed beam with zero energy. These experiments begin to address some of the compatibility problems that exist for future beam heating experiments on EBT devices. In particular, neutral beams are to be a significant part of the planned EBT-II experiment which is designed to demonstrate steady-state, reactor-like conditions with both electron cyclotron heating and neutral beam heating

Neutral gas transport and particle recycling in the W VII-AS stellarator

International Nuclear Information System (INIS)

Sardei, F.; Ringler, H.; Dodhy, A.; Kuehner, G.

1990-01-01

Neutral gas transport simulations with the 3D DEGAS code were applied to model plasmas before the W VII-AS operation was started. For a source of neutrals due to limiter recycling the calculated neutral density distribution is strongly affected by the asymmetries of the magnetic flux surfaces, limiter and wall structures. For a typical ECF heated deuterium discharge from the first months of W VII-AS operation the time histories of H α signals at five toroidal positions provide information about the neutral fluxes due to limiter and wall recycling and to gas puffing. The H α signals are used to scale the calculated 3D distributions of the neutrals and the radial profiles of the ion sources as obtained from the DEGAS code. By comparing the results for the three different neutral sources the limiter is found to provide more than 80% of the plasma refuelling, with a recycling coefficient of about 95%. The calculated total particle fluxes resulting from the integrated ion sources are consistent with neoclassical predictions in the temperature gradient region. Near the plasma edge, however, the fluxes are strongly anomalous. The diffusion coefficient estimated from the fluxes and the measured density gradients (with z eff approx. 3) is about 1/10 - 1/20 of the electron heat conductivity. (author). 6 refs, 10 figs

Comparison of measured and modeled gas-puff emissions on Alcator C-Mod

Science.gov (United States)

Baek, Seung-Gyou; Terry, J. L.; Stotler, D. P.; Labombard, B. L.; Brunner, D. F.

2017-10-01

Understanding neutral transport in tokamak boundary plasmas is important because of its possible effects on the pedestal and scrape-off layer (SOL). On Alcator C-Mod, measured neutral line emissions from externally-puffed deuterium and helium gases are compared with the synthetic results of a neutral transport code, DEGAS 2. The injected gas flow rate and the camera response are absolutely calibrated. Time-averaged SOL density and temperature profiles are input to a steady-state simulation. An updated helium atomic model is employed in DEGAS2. Good agreement is found for the D α peak brightness and profile shape. However, the measured helium I line brightness is found to be lower than that in the simulation results by a roughly a factor of three over a wide range of density particularly in the far SOL region. Two possible causes for this discrepancy are reviewed. First, local cooling due to gas puff may suppress the line emission. Second, time-dependent turbulence effect may impact the helium neutral transport. Unlike deuterium atoms that gain energy from charge exchange and dissociation processes, helium neutrals remain cold and have a relatively short mean free path, known to make them prone to turbulence based on the Kubo number criterion. Supported by USDoE awards: DE-FC02-99ER54512, DE-SC0014251, and DE-AC02-09CH11466.

CAS - CERN Accelerator School and ALBA Synchrotron Light Facility : Course on Vacuum in Accelerators

CERN Document Server

Vacuum in Accelerators

2007-01-01

These proceedings present the lectures given at the twentieth specialized course organized by the CERN Accelerator School (CAS), the topic being Vacuum in Accelerators. The course was held in Platja d’Aro, Spain, from 16 to 24 May 2006. A similar course took place in Snekersten, Denmark, in 1999, with proceedings published as CERN 99-05. After an interval of seven years, the aim of this course was to present a review of the actual state of the art and to highlight the latest developments in the field. The lectures start with a general overview of vacuum, accelerators and cryogenics followed by a more detailed review of the basic principles concerning thermal and non-thermal outgassing. More specialized lectures are then proposed on gas dynamics, on the interaction of energetic particles with matter, and on beam–gas collisions. The production and measurement of vacuum is addressed in subsequent lectures on pumps and vacuum gauges which present a detailed view of the materials currently used in accelerators...

Dynamics of electron acceleration in laser-driven wakefields. Acceleration limits and asymmetric plasma waves

Energy Technology Data Exchange (ETDEWEB)

Popp, Antonia

2011-12-16

The experiments presented in this thesis study several aspects of electron acceleration in a laser-driven plasma wave. High-intensity lasers can efficiently drive a plasma wave that sustains electric fields on the order of 100 GV/m. Electrons that are trapped in this plasma wave can be accelerated to GeV-scale energies. As the accelerating fields in this scheme are 3-4 orders of magnitude higher than in conventional radio-frequency accelerators, the necessary acceleration distance can be reduced by the same factor, turning laser-wakefield acceleration (LWFA) into a promising compact, and potentially cheaper, alternative. However, laser-accelerated electron bunches have not yet reached the parameter standards of conventional accelerators. This work will help to gain better insight into the acceleration process and to optimize the electron bunch properties. The 25 fs, 1.8 J-pulses of the ATLAS laser at the Max-Planck-Institute of Quantum Optics were focused into a steady-state flow gas cell. This very reproducible and turbulence-free gas target allows for stable acceleration of electron bunches. Thus the sensitivity of electron parameters to subtle changes of the experimental setup could be determined with meaningful statistics. At optimized experimental parameters, electron bunches of {approx}50 pC total charge were accelerated to energies up to 450 MeV with a divergence of {approx}2 mrad FWHM. As, in a new design of the gas cell, its length can be varied from 2 to 14 mm, the electron bunch energy could be evaluated after different acceleration distances, at two different electron densities. From this evolution important acceleration parameters could be extracted. At an electron density of 6.43. 10{sup 18} cm{sup -3} the maximum electric field strength in the plasma wave was determined to be {approx}160 GV/m. The length after which the relativistic electrons outrun the accelerating phase of the electric field and are decelerated again, the so-called dephasing length

Dynamics of electron acceleration in laser-driven wakefields. Acceleration limits and asymmetric plasma waves

International Nuclear Information System (INIS)

Popp, Antonia

2011-01-01

The experiments presented in this thesis study several aspects of electron acceleration in a laser-driven plasma wave. High-intensity lasers can efficiently drive a plasma wave that sustains electric fields on the order of 100 GV/m. Electrons that are trapped in this plasma wave can be accelerated to GeV-scale energies. As the accelerating fields in this scheme are 3-4 orders of magnitude higher than in conventional radio-frequency accelerators, the necessary acceleration distance can be reduced by the same factor, turning laser-wakefield acceleration (LWFA) into a promising compact, and potentially cheaper, alternative. However, laser-accelerated electron bunches have not yet reached the parameter standards of conventional accelerators. This work will help to gain better insight into the acceleration process and to optimize the electron bunch properties. The 25 fs, 1.8 J-pulses of the ATLAS laser at the Max-Planck-Institute of Quantum Optics were focused into a steady-state flow gas cell. This very reproducible and turbulence-free gas target allows for stable acceleration of electron bunches. Thus the sensitivity of electron parameters to subtle changes of the experimental setup could be determined with meaningful statistics. At optimized experimental parameters, electron bunches of ∼50 pC total charge were accelerated to energies up to 450 MeV with a divergence of ∼2 mrad FWHM. As, in a new design of the gas cell, its length can be varied from 2 to 14 mm, the electron bunch energy could be evaluated after different acceleration distances, at two different electron densities. From this evolution important acceleration parameters could be extracted. At an electron density of 6.43. 10 18 cm -3 the maximum electric field strength in the plasma wave was determined to be ∼160 GV/m. The length after which the relativistic electrons outrun the accelerating phase of the electric field and are decelerated again, the so-called dephasing length, was found to be 4.9 mm

Current sheet characteristics of a parallel-plate electromagnetic plasma accelerator operated in gas-prefilled mode

Science.gov (United States)

Liu, Shuai; Huang, Yizhi; Guo, Haishan; Lin, Tianyu; Huang, Dong; Yang, Lanjun

2018-05-01

The axial characteristics of a current sheet in a parallel-plate electromagnetic plasma accelerator operated in gas-prefilled mode are reported. The accelerator is powered by a fourteen stage pulse forming network. The capacitor and inductor in each stage are 1.5 μF and 300 nH, respectively, and yield a damped oscillation square wave of current with a pulse width of 20.6 μs. Magnetic probes and photodiodes are placed at various axial positions to measure the behavior of the current sheet. Both magnetic probe and photodiode signals reveal a secondary breakdown when the current reverses the direction. An increase in the discharge current amplitude and a decrease in pressure lead to a decrease in the current shedding factor. The current sheet velocity and thickness are nearly constant during the run-down phase under the first half-period of the current. The current sheet thicknesses are typically in the range of 25 mm to 40 mm. The current sheet velocities are in the range of 10 km/s to 45 km/s when the discharge current is between 10 kA and 55 kA and the gas prefill pressure is between 30 Pa and 800 Pa. The experimental velocities are about 75% to 90% of the theoretical velocities calculated with the current shedding factor. One reason for this could be that the idealized snowplow analysis model ignores the surface drag force.

Development of a compound energy system for cold region houses using small-scale natural gas cogeneration and a gas hydrate battery

International Nuclear Information System (INIS)

Obara, Shin'ya; Kikuchi, Yoshinobu; Ishikawa, Kyosuke; Kawai, Masahito; Yoshiaki, Kashiwaya

2015-01-01

In this study, an independent energy system for houses in cold regions was developed using a small-scale natural gas CGS (cogeneration), air-source heat pump, heat storage tank, and GHB (gas hydrate battery). Heat sources for the GHB were the ambient air and geothermal resources of the cold region. The heat cycle of CO 2 hydrate as a source of energy was also experimentally investigated. To increase the formation speed of CO 2 hydrates, a ferrous oxide–graphite system catalyst was used. The ambient air of cold regions was used as a heat source for the formation process (electric charge) of the GHB, and the heat supplied by a geothermal heat exchanger was used for the dissociation process (electric discharge). Using a geothermal heat source, fuel consumption was halved because of an increased capacity for hydrate formation in the GHB, a shortening of the charging and discharging cycle, and a decrease in the freeze rate of hydrate formation space. Furthermore, when the GHB was introduced into a cold region house, the application rate of renewable energy was 47–71% in winter. The spread of the GHB can greatly reduce fossil fuel consumption and the associated greenhouse gases released from houses in cold regions. - Highlights: • Compound energy system for cold region houses by a gas hydrate battery was proposed. • Heat sources of a gas hydrate battery are exhaust heat of the CGS and geothermal. • Drastic reduction of the fossil fuel consumption in a cold region is realized

Control of electron injection and acceleration in laser-wakefield accelerators

International Nuclear Information System (INIS)

Guillaume, E.

2015-01-01

Laser-plasma accelerators provide a promising compact alternative to conventional accelerators. Plasma waves with extremely strong electric fields are generated when a high intensity laser is focused into an underdense gas target. Electrons that are trapped in these laser-driven plasma waves can be accelerated up to energies of a few GeVs. Despite their great potential, laser-wakefield accelerators face some issues, regarding notably the stability and reproducibility of the beam when electrons are injected in the accelerating structure. In this manuscript, different techniques of electron injection are presented and compared, notably injection in a sharp density gradient and ionization injection. It is shown that combining these two methods allows for the generation of stable and tunable electron beams. We have also studied a way to manipulate the electron bunch in the phase-space in order to accelerate the bunch beyond the dephasing limit. Such a technique was used with quasi-monoenergetic electron beams to enhance their energy. Moreover, the origin of the evolution of the angular momentum of electrons observed experimentally was investigated. Finally, we demonstrated experimentally a new method - the laser-plasma lens - to strongly reduce the divergence of the electron beam. This laser-plasma lens consists of a second gas jet placed at the exit of the accelerator. The laser pulse drives a wakefield in this second jet whose focusing forces take advantage to reduce the divergence of the trailing electron bunch. A simple analytical model describing the principle is presented, underlining the major importance of the second jet length, density and distance from the first jet. Experimental demonstration of the laser-plasma lens shows a divergence reduction by a factor of 2.6 for electrons up to 300 MeV, in accordance with the model predictions

Implications of greenhouse gas emission mitigation scenarios for the main Asian regions

NARCIS (Netherlands)

van Ruijven, B.J.|info:eu-repo/dai/nl/304834521; van Vuuren, D.P.|info:eu-repo/dai/nl/11522016X; van Vliet, J.; Mendoza Beltran, A.; Deetman, S.; den Elzen, M.G.J.

2012-01-01

In order to limit global mean temperature increase, long-term greenhouse gas emissions need to be reduced. This paper discusses the implications of greenhouse gas emission reductions for major Asian regions (China, India, Indonesia, South-East Asia, Japan and Korea) based on results from the IMAGE

Recent status of purging SO2 and NOx in flue gas by EB and R and D of electron accelerator in China

International Nuclear Information System (INIS)

Liu Zhenhao

2005-01-01

The main energy resource is coal in China. Flue gas from burning coal is the most fearful pollution. Chinese Government pays more attention to reduction of SO 2 in flue gas from 1990's. Various technical facilities of reducing SO 2 have been imported from developed countries especially from Japanese companies. For example, A largest project is that Chongqing-luohuang electric power station imported limestone-gypsum process FGD technology and facility from Mitsubishi of Japan in 1980s for 300 MW generator spending 36.4 million US$ and 27.3 million RMB. Recently an example is EBA technology in Chengdu thermal plant. Some of Chinese institute is going to improve the technology to treat larger amount of flue gas from one generator such as 200 - 300 MW generator. And an R and D program of manufacturing higher voltage accelerator is being implemented. Otherwise, electron accelerator of industry application has been successfully made from 20 kW - 100 kW with 2.5 MeV energy in China. (author)

Development of bipolar pulse accelerator for intense pulsed ion beam acceleration

International Nuclear Information System (INIS)

Fujioka, Y.; Mitsui, C.; Kitamura, I.; Takahashi, T.; Masugata, K.; Tanoue, H.; Arai, K.

2003-01-01

To improve the purity of an intense pulsed ion beams a new type of pulsed ion beam accelerator named 'bipolar pulse accelerator (BPA)' was proposed. In the accelerator purity of the beam is expected. To confirm the principle of the accelerator experimental system was developed. The system utilizes B y type magnetically insulated acceleration gap and operated with single polar negative pulse. A coaxial gas puff plasma gun placed in the grounded anode was used as an ion source, and source plasma (nitrogen) of current density approx. = 25 A/cm 2 , duration approx. = 1.5 μs was injected into the acceleration gap. The ions are successfully accelerated from the grounded anode to the drift tube by applying negative pulse of voltage 180 kV, duration 60 ns to the drift tube. Pulsed ion beam of current density approx. = 40 A/cm 2 , duration approx. 60 ns was obtained at 42 mm downstream from the anode surface. (author)

Indication to distinguish the burst region of coal gas from seismic data

Energy Technology Data Exchange (ETDEWEB)

Jian-yuan Cheng; Hong-wei Tang; Lin Xu; Yan-fang Li [China Coal Research Institute, Xi' an (China). Xi' an Research Institute

2009-09-15

The velocity of an over-burst coal seam is about 1/3 compared to a normal coal seam based on laboratory test results. This can be considered as a basis to confirm the area of coal and gas burst by seismic exploration technique. Similarly, the simulation result of the theoretical seismic model shows that there is obvious distinction between over-burst coal and normal coal based on the coal reflection's travel-time, energy and frequency. The results from the actual seismic data acquired in the coal and gas over-burst cases is consistent with that of the laboratory and seismic modeling; that is, in the coal and gas burst region, seismic reflection travel time is delayed, seismic amplitude is weakened and seismic frequency is reduced. Therefore, it can be concluded that seismic exploration technique is promising for use in distinguishing coal and gas over-burst regions based on the variation of seismic reflection travel time, amplitude and frequency. 7 refs., 6 figs.

Towards understanding the influence of electron-gas interactions on imaging in an environmental TEM

DEFF Research Database (Denmark)

Wagner, Jakob Birkedal; Boothroyd, Chris; Beleggia, Marco

2011-01-01

be used. In the differential pumping approach, the gas is confined to the region around the specimen only by pressure-limiting apertures. In order to retain flexibility in the sample region, the pole piece gap and the highest pressure part of the column are relatively large (~7mm). As a result, electron...... on-going work involves the systematic measurements of images, diffraction patterns and energy-loss spectra acquired in the presence of gas, for a variety of different beam current densities, accelerating voltages and choices of specimen....

Focus on regional consequences by allocation of gas contracts

International Nuclear Information System (INIS)

Amundsen, E.S.; Sunnevaag, K.

1994-08-01

The Ministry of Industry and Energy evaluates which of the natural gas fields to be selected for covering the gas supply based on contract obligations. The evaluation aims at giving a total valuation of possible development solutions on the Norwegian continental shelf. Actual solutions are based on fields located in the Haltenbanken area or in the North Sea. The present report relates to a study analysing the consequences on how the employment and regional conditions are influencing the socio-economic and real economic factors by alternative solutions of contract allocations. 38 refs., 9 figs., 7 tabs

Focusing an antimatter beam with matter

CERN Document Server

CERN. Geneva

2000-01-01

An experiment at the Stanford Linear Accelerator Center has recently focused positron beams by means of a plasma lens. This is the first time this process has been observed. The process started with a positron beam from the SLAC PEP-II positron source. This was sent through a damping ring and then accelerated to 28.5 GeV in the SLAC linac with a bunch intensity of 1-2*10/sup 10/. The beam was delivered to the Final Focus Test Beam Facility (FFTB) at a rate of 1 or 10 Hz. At the focal point of the FFTB transport, a special plasma chamber contains a 3 mm diameter pulsed gas nozzle through which either hydrogen or nitrogen gas is "puffed" into the ultrahigh vacuum system at plenum gas pressures up to 75 atm with a discharge time of 800 mu s. The gas is pumped off by a Roots-type pump. On either side of the central chamber are differential pumping sections semi- isolated from each other by thin titanium windows with small (2-5 mm diameter) apertures for the positron beams to pass through. These sections are evacu...

Ultra-high vacuum photoelectron linear accelerator

Science.gov (United States)

Yu, David U.L.; Luo, Yan

2013-07-16

An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

Reble, a radially converging electron beam accelerator

International Nuclear Information System (INIS)

Ramirez, J.J.; Prestwich, K.R.

1976-01-01

The Reble accelerator at Sandia Laboratories is described. This accelerator was developed to provide an experimental source for studying the relevant diode physics, beam propagation, beam energy deposition in a gas using a radially converging e-beam. The nominal parameters for Reble are 1 MV, 200 kA, 20 ns e-beam pulse. The anode and cathode are concentric cylinders with the anode as the inner cylinder. The radial beam can be propagated through the thin foil anode into the laser gas volume. The design and performance of the various components of the accelerator are presented

Railgun-type two step accelerator

International Nuclear Information System (INIS)

Kasai, Satoshi; Maeda, Hikosuke; Onozuka, Masanori; Oda, Yasutsugu; Azuma, Kingo.

1995-01-01

In the two step-type railgun accelerator used in an experimental nuclear fusion device of the present invention, energy of laser beams to be irradiated in an acceleration gas behind a flying object can be reduced, and the voltage applied between the rails can be lowered. Charged particles are generated and supplied to the acceleration gas behind the flying object by a charged particle generating and supplying device so as to promote generation of plasmas caused by irradiation of laser beams. As a result, dielectric break down is caused between the rails by a Paschen's law by application of voltage lower than dielectric breakdown voltage, thereby enabling to generate plasmas easily. Accordingly, the energy of laser beams can be suppressed and the voltage applied between the rails can be lowered. (I.S.)

Railgun-type two step accelerator

Energy Technology Data Exchange (ETDEWEB)

Kasai, Satoshi; Maeda, Hikosuke [Japan Atomic Energy Research Inst., Tokyo (Japan); Onozuka, Masanori; Oda, Yasutsugu; Azuma, Kingo

1995-10-13

In the two step-type railgun accelerator used in an experimental nuclear fusion device of the present invention, energy of laser beams to be irradiated in an acceleration gas behind a flying object can be reduced, and the voltage applied between the rails can be lowered. Charged particles are generated and supplied to the acceleration gas behind the flying object by a charged particle generating and supplying device so as to promote generation of plasmas caused by irradiation of laser beams. As a result, dielectric break down is caused between the rails by a Paschen`s law by application of voltage lower than dielectric breakdown voltage, thereby enabling to generate plasmas easily. Accordingly, the energy of laser beams can be suppressed and the voltage applied between the rails can be lowered. (I.S.).

Puffing and inhalation behaviour in cigarette smoking: Implications for particle diameter and dose

Energy Technology Data Exchange (ETDEWEB)

Dickens, Colin; McGrath, Conor; Warren, Nigel; Biggs, Philip; McAughey, John, E-mail: colin_dickens@bat.co [British American Tobacco, Group R and D Centre, Southampton, SO15 8TL (United Kingdom)

2009-02-01

Inhalation of tobacco smoke aerosol is a two-step process involving puffing followed by inhalation. Measured smoke deposition efficiencies in the lung (20-70%) are greater than expected for smoke particles of diameter 150 - 250 nm CMD. Various mechanisms have been put forward to explain this enhanced deposition pattern, including coagulation, hygroscopic growth, condensation and evaporation, changes in composition, or changes in inhalation behaviour. This paper represents one of a series of studies seeking to better quantify smoke chemistry, inhalation behaviour and cumulative particle growth. The studies have been conducted to better understand smoke dosimetry and links to disease as part of a wider programme defining risk and potential harm reduction. In this study, it was noted that particle deposition increased with increasing inhalation depth, and that smoke inhalation volumes were generally greater than normal tidal breathing volumes. A weak association was observed between particle diameter and puff flow, but no strong association between particle diameter and retention efficiency.

Puffing and inhalation behaviour in cigarette smoking: Implications for particle diameter and dose

International Nuclear Information System (INIS)

Dickens, Colin; McGrath, Conor; Warren, Nigel; Biggs, Philip; McAughey, John

2009-01-01

Inhalation of tobacco smoke aerosol is a two-step process involving puffing followed by inhalation. Measured smoke deposition efficiencies in the lung (20-70%) are greater than expected for smoke particles of diameter 150 - 250 nm CMD. Various mechanisms have been put forward to explain this enhanced deposition pattern, including coagulation, hygroscopic growth, condensation and evaporation, changes in composition, or changes in inhalation behaviour. This paper represents one of a series of studies seeking to better quantify smoke chemistry, inhalation behaviour and cumulative particle growth. The studies have been conducted to better understand smoke dosimetry and links to disease as part of a wider programme defining risk and potential harm reduction. In this study, it was noted that particle deposition increased with increasing inhalation depth, and that smoke inhalation volumes were generally greater than normal tidal breathing volumes. A weak association was observed between particle diameter and puff flow, but no strong association between particle diameter and retention efficiency.

Economic impact of accelerated cleanup on regions surrounding the US DOE's major nuclear weapons sites

International Nuclear Information System (INIS)

Greenberg, M.; Solitare, L.; Frisch, M.; Lowrie, K.

1999-01-01

The regional economic impacts of the US Department of Energy's accelerated environmental cleanup plan are estimated for the major nuclear weapons sites in Colorado, Idaho, New Mexico, South Carolina, Tennessee, and Washington. The analysis shows that the impact falls heavily on the three relatively rural regions around the Savannah River (SC), Hanford (WA), and Idaho National Engineering and Environmental Laboratory (ID) sites. A less aggressive phase-down of environmental management funds and separate funds to invest in education and infrastructure in the regions helps buffer the impacts on jobs, personal income, and gross regional product. Policy options open to the federal and state and local governments are discussed

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

Effective technology transfer through regional information teams

International Nuclear Information System (INIS)

Wicks, D.E.; Gahan, B.; Hoyle, G.

1997-01-01

Communication and the transfer of technical information is critical to the international gas industry. The technical research results developed through Gas Research Institute's natural gas supply program have been disseminated through a number of vehicles. Two primary vehicles are GRI's Information Centers and Regional Technology Transfer Agents (RTTA). The Information Centers serve as repositories for GRI information as well as provide no-cost literature searching expertise. The RTTAs actively communicate and interface with area producers, introducing potential technology adopters with GRI technology managers and/or the appropriate licensed product or service distributors. The combination of Information Centers and RTTAs continues to help independent producers break through the barriers of technology and accelerate the benefits of lower cost natural gas recovery. (au)

Plasma-focused cyclic accelerators

International Nuclear Information System (INIS)

Mondelli, A.A.; Chernin, D.P.

1985-01-01

The use of ambient plasma to neutralize the transverse forces of an intense particle beam has been known for many years. Most recently, the so-called ion-focused regime (IFR) for beam propagation has been used as a means of focusing intense electron beams in linear accelerators and suggested for injecting an electron beam across magnetic field lines into a high-current cyclic accelerator. One technique for generating the required background plasma for IFR propagation is to use a laser to ionize ambient gas in the accelerator chamber. This paper discusses an alternative means of plasma production for IFR, viz. by using RF breakdown. For this approach the accelerator chamber acts as a waveguide. This technique is not limited to toroidal accelerators. It may be applied to any accelerator or recirculator geometry as well as for beam steering and for injection or extraction of beams in closed accelerator configurations

Acidic sweep gas with carbonic anhydrase coated hollow fiber membranes synergistically accelerates CO2 removal from blood

OpenAIRE

Arazawa, D. T.; Kimmel, J. D.; Finn, M.C.; Federspiel, W. J.

2015-01-01

The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (< 500 mL/min) ECCO2R devices necessitates more efficient gas exchange devices. Since over 90% of blood CO2 is transported as bicarbonate (HCO3−), we previously reported development of a carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal ...

Experimental study for the use of sulfur hexafluoride as dielectric gas in particle accelerators

International Nuclear Information System (INIS)

Candanedo y Bernabe, C.

1993-01-01

The sulfur hexafluoride is the better dielectric gas in the world. It is used in particle accelerator, power stations and high voltage transformators. This is a high stable gas, but when is used as dielectric is degraded in toxic and corrosive fluorides this degradation of sulfur hexafluoride is a function of the voltaic arc, crown effect, pressure, temperature and radiation. The purification of the sulfur fluoride permitted to work in safe form and without the risks as contaminant. The objective of the work is the development of a process for the separation of the wastes from the fabrication of sulphur fluoride and the products of degradation. This process used adsorbents when this gas is used as dielectric. The methodology employed was bibliography research, experimental design of the equipment, construction of the experimental equipment, selection and use of adsorbents, installation of the adsorption columns for the experimentation, flow of the sulfur hexafluoride through the adsorbents, searching of the fluoride hexafluoride before and after of the step through the adsorption columns and writing of the results. In base to the results we conclude that the process is good. The work could be advantage using chromatographic techniques with adequate standards. Is possible to extend the study using an additional number of adsorbents. (Author). 34 refs, 7 graphs, 3 tabs

Modeling of thermalization phenomena in coaxial plasma accelerators

Science.gov (United States)

Subramaniam, Vivek; Panneerchelvam, Premkumar; Raja, Laxminarayan L.

2018-05-01

Coaxial plasma accelerators are electromagnetic acceleration devices that employ a self-induced Lorentz force to produce collimated plasma jets with velocities ~50 km s‑1. The accelerator operation is characterized by the formation of an ionization/thermalization zone near gas inlet of the device that continually processes the incoming neutral gas into a highly ionized thermal plasma. In this paper, we present a 1D non-equilibrium plasma model to resolve the plasma formation and the electron-heavy species thermalization phenomena that take place in the thermalization zone. The non-equilibrium model is based on a self-consistent multi-species continuum description of the plasma with finite-rate chemistry. The thermalization zone is modelled by tracking a 1D gas-bit as it convects down the device with an initial gas pressure of 1 atm. The thermalization process occurs in two stages. The first is a plasma production stage, associated with a rapid increase in the charged species number densities facilitated by cathode surface electron emission and volumetric production processes. The production stage results in the formation of a two-temperature plasma with electron energies of ~2.5 eV in a low temperature background gas of ~300 K. The second, a temperature equilibration stage, is characterized by the energy transfer between the electrons and heavy species. The characteristic length scale for thermalization is found to be comparable to axial length of the accelerator thus putting into question the equilibrium magnetohydrodynamics assumption used in modeling coaxial accelerators.

On gas sweeping from central regions of galaxies with active nuclei

International Nuclear Information System (INIS)

Silich, S.A.; Fomin, P.I.

1980-01-01

A mechanism of gas sweeping by shock waves from central regions of plane galaxies with active nuclei which is connected with the angular moment transfer from a stellar-cloud component to a gas one is considered. It is shown that shock waves are capable to form the observable density profile with the maximum at a distance of some kpc from galaxy centre for the time of the order of 10 9 years

Characteristics of particle beam acceleration on KUMS tandem electrostatic accelerator 5SDH-2

OpenAIRE

谷池, 晃; 古山, 雄一; 北村, 晃

2006-01-01

The KUMS tandem electrostatic accelerator, 5SDH-2, was installed in 1996. Ten years have passed since it installed and we obtain some data for accelerator operations. We report the particle beam characteristics such as relation between beam species and switcher magnet current, and dependence of ion charge fraction on stripper gas thickness. We also try to generate nitrogen ion beams, and low energy ion beams.

A framework for diagnosing the regional impacts of energy price policies. An application to natural gas deregulation

Energy Technology Data Exchange (ETDEWEB)

Bender, S.; Kalt, J.P.; Lee, H.

1986-03-01

Energy policy debates in the U.S. have frequently centered upon asserted regional effects. 'Consuming' regions are commonly pitted against 'producing' regions, with the latter purportedly gaining/losing at the expense of the former under higher/lower energy prices. Such simple views ignore regional trade linkages, the geographic distribution of ownership in energy using and producing firms, and the microeconomics of the incidence of energy price changes. This study presents a framework which incorporates these factors and allows assessment of the net regional income effects of changing energy prices. When applied to U.S. natural gas policy, the study's results indicate that the income effects of a rise in gas prices tend to be much more evenly spread than a naive assignment of increased costs and revenues to consuming and producing regions, respectively, would indicate. Under a number of plausible scenarios, in fact, it is likely that certain net gas consuming regions (e.g., the Pacific Northwest) have benefitted from the recent deregulation of U.S. gas prices. 14 refs. (A.V.)

Wellhead to wire utilization of remote gas resources

International Nuclear Information System (INIS)

Harris, R.A.; Hines, T.L.

1998-01-01

Utilization of remote gas resources in developing countries continues to offer challenges and opportunities to producers and contractors. The Aguaytia Gas and Power Project is an example where perseverance and creativity resulted in successful utilization of natural gas resources in the Ucayali Region of Central Peru, a country which previously had no natural gas infrastructure. The resource for the project was first discovered by Mobil in 1961, and remained undeveloped for over thirty years due to lack of infrastructure and markets. Maple Gas won a competitively bid contract to develop the Aguaytia gas reserves in March of 1993. The challenges facing Maple Gas were to develop downstream markets for the gas, execute contracts with Perupetro S.A. and other Peruvian government entities, raise financing for the project, and solicit and execute engineering procurement and construction (EPC) contracts for the execution of the project. The key to development of the downstream markets was the decision to generate electric power and transmit the power over the Andes to the main electrical grid along the coast of Peru. Supplemental revenue could be generated by gas sales to a small regional power plant and extraction of LPG and natural gasoline for consumption in the Peruvian market. Three separate lump sum contracts were awarded to Asea Brown Boveri (ABB) companies for the gas project, power project and transmission project. Each project presented its unique challenges, but the commonalities were the accelerated schedule, high rainfall in a prolonged wet season and severe logistics due to lack of infrastructure in the remote region. This presentation focuses on how the gas plant contractor, ABB Randall, working in harmony with the developer, Maple Gas, tackled the challenges to monetize a remote gas resource

Langmuir probe measurements of the scrape-off plasma in ISX-A

International Nuclear Information System (INIS)

Namkung, W.; England, A.C.; Eldridge, O.C.

1978-11-01

A fixed double Langmuir probe was used to investigate the temporal behavior of the scrape-off plasma in the ISX-A tokamak. During gas puffing, the ion saturation current dropped rapidly to a very low level while the line average density showed a steady increase. This sudden transition was due mainly to a density change of more than a factor of five while the electron temperature remained relatively constant at approximately 10 eV. This behavior was easily observed at points away from the limiter with mild and moderate gas puffing rates, and near the inner edge of the limiter with strong gas puffing. In order to explain the phenomenon, it is suggested that there may be two distinct layers in the scrape-off plasma and that the boundary between the layers moves inward toward the limiter. The existence of the boundary has been confirmed indirectly by sudden shifts of the plasma during feedback control experiments

The impact of the North American shale gas revolution on regional natural gas markets: Evidence from the regime-switching model

International Nuclear Information System (INIS)

Geng, Jiang-Bo; Ji, Qiang; Fan, Ying

2016-01-01

This paper investigates the impact of the North American shale gas revolution on price movement regimes in the North American and European gas markets, using the Markov regime-switching model. It then measures price spreads between oil and gas from 1998 to 2015 to identify the impact of the revolution on the relationship between oil and regional gas prices. The results show that the typical movement regime of Henry Hub prices changes from 'slightly upward' to 'sharply downward'. In addition, the clear seasonal effect of Henry Hub prices has disappeared after the shale gas revolution. The typical movement of national balancing point (NBP) prices has changed gradually from a 'sharply upward' regime to the alternative regimes between 'sharply downward' and 'slightly upward', tending to follow oil prices. This indicates that the shale gas revolution has had little impact on NBP price movement. Meanwhile, Henry Hub prices have decoupled from WTI prices, while NBP and Brent prices have continued to exhibit a long-term equilibrium level around which they have swung in the short time-frame since the shale gas revolution. Pertinent energy policy makers and energy market participants should pay attention to these changes and adjust their trade, production and investment strategies accordingly. - Highlights: •Impact of shale gas revolution on Henry Hub and NBP price movement regime is analysed. •Impact of revolution on relationship between oil and regional gas price is identified. •Revolution changes Henry Hub movement regime, having minor impact on NBP regime. •Clear seasonal fluctuation of Henry Hub prices has disappeared since the revolution. •Henry Hub has decoupled from WTI, while NBP and Brent exhibit long-term equilibrium.

Trial of accelerator cells machining with high precision and high efficiency at Okayama region

International Nuclear Information System (INIS)

Yoshikawa, Mitsuo; Yoden, Hiroyuki; Yokomizo, Seiichi; Sumida, Tsuneto; Kunishida, Jun; Oshita, Isao

2005-01-01

In the framework of the project 'Promotion of Science and Technology in Regional Areas' by the Ministry of Education, Culture, Sports, Science and Technology, we have prepared a special apparatus for machining accelerator cells with a high precision and a high efficiency for the future linear collider. A machining with as small an error as 2 micrometers has been realized. Necessary time to finish one accelerator cell is reduced from 128 minutes to 34 minutes due to the suppression of the heating of the object at the machining. If newly developed one chuck method was employed, the precision and efficiency would be further improved. By cutting at both sides of the spindle, the necessary time for machining would be reduced by half. (author)

Preoperative concurrent CBDCA chemotherapy and accelerated hyperfractionated radiotherapy for squamous cell carcinoma of the maxillary region

International Nuclear Information System (INIS)

Omura, Ken; Harada, Hiroyuki; Suzuki, Haruhiko; Takeuchi, Yosuke; Hatano, Kazuo; Togawa, Takashi

2001-01-01

Between 1994 and 2000, 28 patients with T3/T4 squamus cell carcinoma of the maxillary region (maxillary sinus, 22; maxillary gingiva, 4; maxillary bone, 1; buccal mucosa, 1) had accelerated hyperfractionated radiotherapy combined with simultaneous CBDCA chemotherapy preoperatively, at Chiba Cancer Center Hospital. The protocol consisted of combined therapy with accelerated hyperfractionated irradiation of 1.6 Gy, twice a day, to a total dose of 32.0-51.2 Gy and concurrent intra-arterial or intravenous infusion of CBDCA 20-30 mg/body/day for a cumulative total dose of 270-480 mg. After completion of the preoperative combined therapy, the clinical CR rate was 17.9%, and the good PR·CR rate was 32.1%. According to the initial findings and response to the combined therapy, all patients had maxillectomy (subtotal, 3; total, 16; extended, 9) 4 weeks after completion of the preoperative combined therapy. Postoperatively, the complete pathologic response (Ohboshi and Shimozato's classification, grade III and IV) rate was 28.6%. And the actuarial local control rate was 85.7%, with a mean follow-up of 46.2 months. Based on these results, we believe this preoperative therapy with CBDCA chemotherapy and accelerated hyperfractionated radiation is a significant choice as treatment for squamous cell cancer of the maxillary region. (author)

Development of plasma fueling on EAST

International Nuclear Information System (INIS)

Yao, X.J.; Zheng, X.W.; Li, C.Z.; Chen, Y.

2015-01-01

To achieve better plasma density control, experimental advanced superconducting tokamak (EAST) has already equipped with gas puffing (GP), supersonic molecular beam injection (SMBI) and pellet injection (PI). During the past few years, lots of experiments and ameliorations have been done. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. And the preliminary result of pellet injection was also presented here. The results shows the PI and SMBI were more compatible to the long pulse high density discharge on EAST. (author)

Working paper Green Gas. Overview of policy issues on Green Gas; Werkdocument Groen Gas. Overzicht Beleidsvraagstukken Groen Gas

Energy Technology Data Exchange (ETDEWEB)

Dumont, M.

2012-07-15

Early 2010, the interdepartmental Accelerator Team Green Gas was established which deals with policy issues in the field of Green Gas. This working document reflects the current state of affairs. Via the website www.groengas.nl new versions will be made available on a regular basis [Dutch] Begin 2010 is het interdepartementale Versnellerteam Groen Gas opgericht dat zich bezighoudt met vraagstukken op het gebied van Groen Gas die op het terrein van de rijksoverheid liggen. Dit werkdocument geeft de huidige stand van zaken weer. Via www.groengas.nl komen geregeld nieuwe versies beschikbaar.

Advanced fuelling system for use as a burn control tool in a burning plasma device

Energy Technology Data Exchange (ETDEWEB)

Raman, R. [Washington Univ., Seattle, WA (United States)

2007-07-01

Steady-state Advanced Tokamak (AT) scenarios rely on optimized density and pressure profiles to maximize the bootstrap current fraction. Under this mode of operation, the fuelling system must deposit small amounts of fuel where it is needed, and as often as needed, so as to compensate for fuel losses, but not to adversely alter the established density and pressure profiles. Conventional fuelling methods have not demonstrated successful fuelling of ATtype discharges and may be incapable of deep fuelling long pulse ELM-free discharges in ITER. The capability to deposit fuel at any desired radial location within the tokamak would provide burn control capability through alteration of the density profile. The ability to peak the density profile would ease ignition requirements, while operating ITER with density profiles that are peaked would increase the fusion power output. An advanced fuelling system should also be capable of fuelling well past internal transport barriers. Compact Toroid (CT) fuelling [R. Raman, et al., 'Experimental demonstration of tokamak fuelling by compact toroid injection,' Nucl. Fusion, 37, 967 (1997)] has the potential to meet these needs, while simultaneously providing a source of toroidal momentum input. A CT is a selfcontained toroidal plasmoid with embedded magnetic fields. The 20 Hz injector consists of the formation region, compression, acceleration and transport regions. Fuel gas is puffed into the formation region, and a combination of magnetic field and electric current ionizes this gas and creates a self-contained plasma ring (the 'CT'). Then a fast current pulse compresses and accelerates the CT by electromagnetic forces. The accelerated CT will travel at a speed of over 30 cm/{mu}s and for reactors will create a particle inventory perturbation of < 1% per pulse. At this level of particle inventory perturbation, optimized density profiles will not be adversely perturbed. Experimental data needed for the design of

KEK digital accelerator

Directory of Open Access Journals (Sweden)

T. Iwashita

2011-07-01

Full Text Available The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

Innovative applications of genetic algorithms to problems in accelerator physics

Directory of Open Access Journals (Sweden)

Alicia Hofler

2013-01-01

Full Text Available The genetic algorithm (GA is a powerful technique that implements the principles nature uses in biological evolution to optimize a multidimensional nonlinear problem. The GA works especially well for problems with a large number of local extrema, where traditional methods (such as conjugate gradient, steepest descent, and others fail or, at best, underperform. The field of accelerator physics, among others, abounds with problems which lend themselves to optimization via GAs. In this paper, we report on the successful application of GAs in several problems related to the existing Continuous Electron Beam Accelerator Facility nuclear physics machine, the proposed Medium-energy Electron-Ion Collider at Jefferson Lab, and a radio frequency gun-based injector. These encouraging results are a step forward in optimizing accelerator design and provide an impetus for application of GAs to other problems in the field. To that end, we discuss the details of the GAs used, include a newly devised enhancement which leads to improved convergence to the optimum, and make recommendations for future GA developments and accelerator applications.

On acceleration of <1 MeV/n He ions in the corotating compression regions near 1 AU: STEREO observations

Directory of Open Access Journals (Sweden)

R. Bučík

2009-09-01

Full Text Available Observations of multi-MeV corotating interaction region (CIR ions are in general consistent with models of CIR shock acceleration and transport. The presence of suprathermal particles near 1 AU in unshocked compression regions is not adequately explained. Nonetheless, more recent works demonstrate that unshocked compression regions associated with CIRs near 1 AU could energize particles. In the energy range from ~0.1 to ~1 MeV/n we investigate CIR events observed in 2007–2008 by the STEREO A and B spacecraft. We treat the predictions of compression acceleration by comparing the observed ion intensities with the model parameters. These observations show that the ion intensity in CIR events with in-situ reverse shock is well organized by the parameters which characterize the compression region itself, like compression width, solar wind speed gradients and the total pressure. In turn, for CIR events with the absence of the shocks the model predictions are not fulfilled.

H.V. support structure of 3MVDC generator and its protection from HV discharges in vacuum and SF6 gas for DC electron accelerator

International Nuclear Information System (INIS)

Sharma, D.K.; Rajan, R.N.; Srivastava, S.K.; Dewangan, S.; Jayaprakash, D.; Bakhtsingh, R.I.; Acharya, S.; Gantayet, L.M.

2014-01-01

Accelerator and Pulse Power Division of BARC has developed a DC electron accelerator for cross linking of polymers, medical sterilisation, preservation of food. The demonstration of stack-gas cleanup for green power generation has been demonstrated successfully. The support structure of the 3MVDC voltage generator is made of Perspex for high dielectric strength, easy availability of raw material, excellent radiation resistance and long term dimensional stability. This paper describes the salient design features of the High voltage support structure in brief. (author)

H.V. support structure of 3MVDC generator and its protection from HV discharges in vacuum and SF6 gas for DC electron accelerator

Energy Technology Data Exchange (ETDEWEB)

Sharma, D.K.; Rajan, R.N.; Srivastava, S.K.; Dewangan, S.; Jayaprakash, D.; Bakhtsingh, R.I.; Acharya, S.; Gantayet, L.M., E-mail: dksharma@barc.gov.in [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

2014-07-01

Accelerator and Pulse Power Division of BARC has developed a DC electron accelerator for cross linking of polymers, medical sterilisation, preservation of food. The demonstration of stack-gas cleanup for green power generation has been demonstrated successfully. The support structure of the 3MVDC voltage generator is made of Perspex for high dielectric strength, easy availability of raw material, excellent radiation resistance and long term dimensional stability. This paper describes the salient design features of the High voltage support structure in brief. (author)

Indian National Gas Hydrate Program Expedition 01 report

Science.gov (United States)

Collett, Timothy S.; Riedel, M.; Boswell, R.; Presley, J.; Kumar, P.; Sathe, A.; Sethi, A.; Lall, M.V.; ,

2015-01-01

Gas hydrate is a naturally occurring “ice-like” combination of natural gas and water that has the potential to serve as an immense resource of natural gas from the world’s oceans and polar regions. However, gas-hydrate recovery is both a scientific and a technical challenge and much remains to be learned about the geologic, engineering, and economic factors controlling the ultimate energy resource potential of gas hydrate. The amount of natural gas contained in the world’s gas-hydrate accumulations is enormous, but these estimates are speculative and range over three orders of magnitude from about 2,800 to 8,000,000 trillion cubic meters of gas. By comparison, conventional natural gas accumulations (reserves and undiscovered, technically recoverable resources) for the world are estimated at approximately 440 trillion cubic meters. Gas recovery from gas hydrate is hindered because the gas is in a solid form and because gas hydrate commonly occurs in remote Arctic and deep marine environments. Proposed methods of gas recovery from gas hydrate generally deal with disassociating or “melting” in situ gas hydrate by heating the reservoir beyond the temperature of gas-hydrate formation, or decreasing the reservoir pressure below hydrate equilibrium. The pace of energy-related gas hydrate assessment projects has accelerated over the past several years.

Accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator

International Nuclear Information System (INIS)

Surendran, P.; Shrivastava, A.; Gupta, A.K.; Nair, J.P.; Yadav, M.L.; Gore, J.A.; Sparrow, H.; Bhagwat, P.V.; Kailas, S.

2006-01-01

Accelerator based mass spectrometry (ABMs) is an ultra sensitive means of counting individual atoms having sufficiently long half life and available in small amount. The 14 U D Pelletron Accelerator is an ideal machine to carry out ABMs studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radio isotope 36 Cl is widely being detected using ABMs as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc. As a part of the ongoing ABMs programme at 14UD Pelletron Accelerator Facility at Mumbai, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has been developed. Further progress made in this programme is discussed in this paper. (author)

The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

CERN Document Server

Ciocarlan, C.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; 10.1063/1.4822333

2013-01-01

The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive selffocusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.01018 cm3, the peak normalized...

Estimating regional greenhouse gas fluxes: An uncertainty analysis of planetary boundary layer techniques and bottom-up inventories

Science.gov (United States)

Quantification of regional greenhouse gas (GHG) fluxes is essential for establishing mitigation strategies and evaluating their effectiveness. Here, we used multiple top-down approaches and multiple trace gas observations at a tall tower to estimate GHG regional fluxes and evaluate the GHG fluxes de...

Interface for the rapid analysis of liquid samples by accelerator mass spectrometry

Science.gov (United States)

Turteltaub, Kenneth; Ognibene, Ted; Thomas, Avi; Daley, Paul F; Salazar Quintero, Gary A; Bench, Graham

2014-02-04

An interface for the analysis of liquid sample having carbon content by an accelerator mass spectrometer including a wire, defects on the wire, a system for moving the wire, a droplet maker for producing droplets of the liquid sample and placing the droplets of the liquid sample on the wire in the defects, a system that converts the carbon content of the droplets of the liquid sample to carbon dioxide gas in a helium stream, and a gas-accepting ion source connected to the accelerator mass spectrometer that receives the carbon dioxide gas of the sample in a helium stream and introduces the carbon dioxide gas of the sample into the accelerator mass spectrometer.

Research on the electromagnetic radiation characteristics of the gas main switch of a capacitive intense electron-beam accelerator

Directory of Open Access Journals (Sweden)

Yongfeng Qiu

2017-11-01

Full Text Available Strong electromagnetic fields are radiated during the operation of the intense electron-beam accelerator (IEBA, which may lead to the nearby electronic devices out of order. In this paper, the research on the electromagnetic radiation characteristic of the gas main switch of a capacitive IEBA is carried out by the methods of theory analysis and experiment investigation. It is obtained that the gas main switch is the dominating radiation resource. In the absence of electromagnetic shielding for the gas main switch, when the pulse forming line of the IEBA is charged to 700 kV, the radiation field with amplitude of 3280 V/m, dominant frequency of 84 MHz and high frequency 100 MHz is obtained at a distance of 10 meters away from the gas main switch. The experimental results of the radiation field agree with the theoretical calculations. We analyze the achievements of several research groups and find that there is a relationship between the rise time (T of the transient current of the gas main switch and the dominant frequency (F of the radiation field, namely, F*T=1. Contrast experiment is carried out with a metal shield cover for the gas main switch. Experimental results show that for the shielded setup the radiation field reduces to 115 V/m, the dominant frequency increases to 86.5 MHz at a distance of 10 away meters from the gas main switch. These conclusions are beneficial for further research on the electromagnetic radiation and protection of the IEBA.

UNIFORM INFALL TOWARD THE COMETARY H II REGION IN THE G34.26+0.15 COMPLEX?

Energy Technology Data Exchange (ETDEWEB)

Liu, Tie; Wu, Yuefang; Zhang, Huawei, E-mail: liutiepku@gmail.com, E-mail: ywu@pku.edu.cn [Department of Astronomy, Peking University, 100871 Beijing (China)

2013-10-10

Gas accretion is a key process in star formation. However, gas infall detections in high-mass, star-forming regions with high spatial resolution observations are rare. Here, we report the detection of gas infall toward a cometary ultracompact H II region ({sup C)} in the G34.26+0.15 complex. The observations were made with the IRAM 30 m, the James Clerk Maxwell Telescope 15 m telescope, and the Submillimeter Array (SMA). The hot core associated with 'C' has a mass of ∼76 ± 11 M{sub ☉} and a volume density of (1.1 ± 0.2) × 10{sup 8} cm{sup –3}. The HCN (3-2) and HCO{sup +} (1-0) lines observed by single dishes and the CN (2-1) lines observed by the SMA show redshifted absorption features, indicating gas infall. We found a linear relationship between the line width and optical depth of the CN (2-1) lines. Those transitions with larger optical depths and line widths have larger absorption areas. However, the infall velocities measured from different lines seem to be constant, indicating that the gas infall is uniform. We also investigated the evolution of gas infall in high-mass, star-forming regions. A tight relationship was found between the infall velocity and the total dust/gas mass. At stages prior to the hot core phase, the typical infall velocity and mass infall rate are ∼1 km s{sup –1} and ∼10{sup –4} M{sub ☉} yr{sup –1}, respectively. While in more evolved regions, the infall velocity and mass infall rates can reach as high as several km s{sup –1} and ∼10{sup –3}-10{sup –2} M{sub ☉} yr{sup –1}, respectively. Accelerated infall has been detected toward some hypercompact H II and ultracompact H II regions. However, the acceleration phenomenon is not seen in more evolved ultracompact H II regions (e.g., G34.26+0.15)

UNIFORM INFALL TOWARD THE COMETARY H II REGION IN THE G34.26+0.15 COMPLEX?

International Nuclear Information System (INIS)

Liu, Tie; Wu, Yuefang; Zhang, Huawei

2013-01-01

Gas accretion is a key process in star formation. However, gas infall detections in high-mass, star-forming regions with high spatial resolution observations are rare. Here, we report the detection of gas infall toward a cometary ultracompact H II region ( C) in the G34.26+0.15 complex. The observations were made with the IRAM 30 m, the James Clerk Maxwell Telescope 15 m telescope, and the Submillimeter Array (SMA). The hot core associated with 'C' has a mass of ∼76 ± 11 M ☉ and a volume density of (1.1 ± 0.2) × 10 8 cm –3 . The HCN (3-2) and HCO + (1-0) lines observed by single dishes and the CN (2-1) lines observed by the SMA show redshifted absorption features, indicating gas infall. We found a linear relationship between the line width and optical depth of the CN (2-1) lines. Those transitions with larger optical depths and line widths have larger absorption areas. However, the infall velocities measured from different lines seem to be constant, indicating that the gas infall is uniform. We also investigated the evolution of gas infall in high-mass, star-forming regions. A tight relationship was found between the infall velocity and the total dust/gas mass. At stages prior to the hot core phase, the typical infall velocity and mass infall rate are ∼1 km s –1 and ∼10 –4 M ☉ yr –1 , respectively. While in more evolved regions, the infall velocity and mass infall rates can reach as high as several km s –1 and ∼10 –3 -10 –2 M ☉ yr –1 , respectively. Accelerated infall has been detected toward some hypercompact H II and ultracompact H II regions. However, the acceleration phenomenon is not seen in more evolved ultracompact H II regions (e.g., G34.26+0.15)

Noncommutative field gas driven inflation

Energy Technology Data Exchange (ETDEWEB)

Barosi, Luciano; Brito, Francisco A [Departamento de Fisica, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraiba (Brazil); Queiroz, Amilcar R, E-mail: lbarosi@ufcg.edu.br, E-mail: fabrito@df.ufcg.edu.br, E-mail: amilcarq@gmail.com [Centro Internacional de Fisica da Materia Condensada, Universidade de Brasilia, Caixa Postal 04667, Brasilia, DF (Brazil)

2008-04-15

We investigate early time inflationary scenarios in a Universe filled with a dilute noncommutative bosonic gas at high temperature. A noncommutative bosonic gas is a gas composed of a bosonic scalar field with noncommutative field space on a commutative spacetime. Such noncommutative field theories were recently introduced as a generalization of quantum mechanics on a noncommutative spacetime. Key features of these theories are Lorentz invariance violation and CPT violation. In the present study we use a noncommutative bosonic field theory that, besides the noncommutative parameter {theta}, shows up a further parameter {sigma}. This parameter {sigma} controls the range of the noncommutativity and acts as a regulator for the theory. Both parameters play a key role in the modified dispersion relations of the noncommutative bosonic field, leading to possible striking consequences for phenomenology. In this work we obtain an equation of state p = {omega}({sigma},{theta};{beta}){rho} for the noncommutative bosonic gas relating pressure p and energy density {rho}, in the limit of high temperature. We analyse possible behaviours for these gas parameters {sigma}, {theta} and {beta}, so that -1{<=}{omega}<-1/3, which is the region where the Universe enters an accelerated phase.

Acceleration of Gas Flow Simulations in Dual-Continuum Porous Media Based on the Mass-Conservation POD Method

KAUST Repository

Wang, Yi

2017-09-12

Reduced-order modeling approaches for gas flow in dual-porosity dual-permeability porous media are studied based on the proper orthogonal decomposition (POD) method combined with Galerkin projection. The typical modeling approach for non-porous-medium liquid flow problems is not appropriate for this compressible gas flow in a dual-continuum porous media. The reason is that non-zero mass transfer for the dual-continuum system can be generated artificially via the typical POD projection, violating the mass-conservation nature and causing the failure of the POD modeling. A new POD modeling approach is proposed considering the mass conservation of the whole matrix fracture system. Computation can be accelerated as much as 720 times with high precision (reconstruction errors as slow as 7.69 × 10−4%~3.87% for the matrix and 8.27 × 10−4%~2.84% for the fracture).

Acceleration of Gas Flow Simulations in Dual-Continuum Porous Media Based on the Mass-Conservation POD Method

KAUST Repository

Wang, Yi; Sun, Shuyu; Yu, Bo

2017-01-01

Reduced-order modeling approaches for gas flow in dual-porosity dual-permeability porous media are studied based on the proper orthogonal decomposition (POD) method combined with Galerkin projection. The typical modeling approach for non-porous-medium liquid flow problems is not appropriate for this compressible gas flow in a dual-continuum porous media. The reason is that non-zero mass transfer for the dual-continuum system can be generated artificially via the typical POD projection, violating the mass-conservation nature and causing the failure of the POD modeling. A new POD modeling approach is proposed considering the mass conservation of the whole matrix fracture system. Computation can be accelerated as much as 720 times with high precision (reconstruction errors as slow as 7.69 × 10−4%~3.87% for the matrix and 8.27 × 10−4%~2.84% for the fracture).

Preoperative concurrent CBDCA chemotherapy and accelerated hyperfractionated radiotherapy for squamous cell carcinoma of the maxillary region

Energy Technology Data Exchange (ETDEWEB)

Omura, Ken; Harada, Hiroyuki [Tokyo Medical and Dental Univ. (Japan). Graduate School; Suzuki, Haruhiko; Takeuchi, Yosuke; Hatano, Kazuo; Togawa, Takashi

2001-11-01

Between 1994 and 2000, 28 patients with T3/T4 squamus cell carcinoma of the maxillary region (maxillary sinus, 22; maxillary gingiva, 4; maxillary bone, 1; buccal mucosa, 1) had accelerated hyperfractionated radiotherapy combined with simultaneous CBDCA chemotherapy preoperatively, at Chiba Cancer Center Hospital. The protocol consisted of combined therapy with accelerated hyperfractionated irradiation of 1.6 Gy, twice a day, to a total dose of 32.0-51.2 Gy and concurrent intra-arterial or intravenous infusion of CBDCA 20-30 mg/body/day for a cumulative total dose of 270-480 mg. After completion of the preoperative combined therapy, the clinical CR rate was 17.9%, and the good PR{center_dot}CR rate was 32.1%. According to the initial findings and response to the combined therapy, all patients had maxillectomy (subtotal, 3; total, 16; extended, 9) 4 weeks after completion of the preoperative combined therapy. Postoperatively, the complete pathologic response (Ohboshi and Shimozato's classification, grade III and IV) rate was 28.6%. And the actuarial local control rate was 85.7%, with a mean follow-up of 46.2 months. Based on these results, we believe this preoperative therapy with CBDCA chemotherapy and accelerated hyperfractionated radiation is a significant choice as treatment for squamous cell cancer of the maxillary region. (author)

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

Science.gov (United States)

Persaud, A.; Seidl, P. A.; Ji, Q.; Feinberg, E.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Lal, A.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3 × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.

Giessen polarization facility. II. 1. 2 MeV tandem accelerator

Energy Technology Data Exchange (ETDEWEB)

Arnold, W; Ulbricht, J; Berg, H; Keiner, P; Krause, H H; Schmidt, R; Clausnitzer, G [Giessen Univ. (Germany, F.R.). Strahlenzentrum

1977-06-15

A small pressure insulated tandem accelerator with 600 kV terminal voltage was constructed for the application of a polarized ion source of the Lambshift type: thin carbon foils or gas stripping is used for the charge exchange in the high voltage terminal. The calculated ion optical properties were realized in the construction; transmission and energy resolution are sufficient to obtain high intensity polarized beams on target (maximum 0.6..mu..A protons with P=0.75 ) for precision polarization experiments in the 0.2-1.2 MeV energy region.

Optical plasma torch electron bunch generation in plasma wakefield accelerators

Directory of Open Access Journals (Sweden)

G. Wittig

2015-08-01

Full Text Available A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

Uncovering China’s greenhouse gas emission from regional and sectoral perspectives

International Nuclear Information System (INIS)

Liu, Zhu; Geng, Yong; Lindner, Soeren; Guan, Dabo

2012-01-01

Understanding China’s GHG (greenhouse gas) emission status is critical for achieving the national mitigation plan. While much attention has addressed China’s national level GHG emission, less is known about its regional and sectoral emission features. In this paper China’s regional and sectoral GHG emission patterns and their driving forces were explored by using upgraded energy consumption data. We constructed a detailed GHG inventory for each province in the year 2009 which covering 28 sectors and further expanded time-serious inventories during 1997–2009. We then conducted variation and index decomposition analysis to explore its sectoral/regional disparity and features. Results showed significant differences of sectoral emission intensity among different provinces, implying a huge disparity of technology level. Since less developed provinces still apply energy intensive technologies, they had contributed to most of national emission increment during 1997–2009 and made the whole country towards carbon intensive direction. Our research outcomes indicate that the inequity of technology level among regions has already become a main barrier for China’s CO 2 mitigation. Such a reality deserves more attention from both researchers and policy makers so that appropriate carbon reduction policies can be raised. -- Highlights: ► We present spacial and sectoral disparity and drivers on green house gas (GHG) emission in 30 Chinese provinces. ► We indicated a huge difference of technology level among regions. ► Different industrial structure and development stage further result in GHG intensive in China's poor regions. ► Inequity of technology level among regions has already become a main barrier for China's GHG mitigation.

A novel gridding algorithm to create regional trace gas maps from satellite observations

Science.gov (United States)

Kuhlmann, G.; Hartl, A.; Cheung, H. M.; Lam, Y. F.; Wenig, M. O.

2014-02-01

The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2) onto a longitude-latitude grid (level 3). The algorithm is designed for the Ozone Monitoring Instrument (OMI) and can easily be employed for similar instruments - for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI). Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly developed gridding

A novel gridding algorithm to create regional trace gas maps from satellite observations

Directory of Open Access Journals (Sweden)

G. Kuhlmann

2014-02-01

Full Text Available The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2 onto a longitude–latitude grid (level 3. The algorithm is designed for the Ozone Monitoring Instrument (OMI and can easily be employed for similar instruments – for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI. Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly

The comparison of physical properties derived from gas and dust in a massive star-forming region

Energy Technology Data Exchange (ETDEWEB)

Battersby, Cara; Bally, John; Ginsburg, Adam; Darling, Jeremy [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309 (United States); Dunham, Miranda [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Longmore, Steve [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)

2014-05-10

We explore the relationship between gas and dust in a massive star-forming region by comparing the physical properties derived from each. We compare the temperatures and column densities in a massive star-forming Infrared Dark Cloud (G32.02+0.05), which shows a range of evolutionary states, from quiescent to active. The gas properties were derived using radiative transfer modeling of the (1,1), (2,2), and (4,4) transitions of NH{sub 3} on the Karl G. Jansky Very Large Array, while the dust temperatures and column densities were calculated using cirrus-subtracted, modified blackbody fits to Herschel data. We compare the derived column densities to calculate an NH{sub 3} abundance, χ{sub NH{sub 3}} = 4.6 × 10{sup –8}. In the coldest star-forming region, we find that the measured dust temperatures are lower than the measured gas temperatures (mean and standard deviations T {sub dust,} {sub avg} ∼ 11.6 ± 0.2 K versus T {sub gas,} {sub avg} ∼ 15.2 ± 1.5 K), which may indicate that the gas and dust are not well-coupled in the youngest regions (∼0.5 Myr) or that these observations probe a regime where the dust and/or gas temperature measurements are unreliable. Finally, we calculate millimeter fluxes based on the temperatures and column densities derived from NH{sub 3}, which suggest that millimeter dust continuum observations of massive star-forming regions, such as the Bolocam Galactic Plane Survey or ATLASGAL, can probe hot cores, cold cores, and the dense gas lanes from which they form, and are generally not dominated by the hottest core.

The comparison of physical properties derived from gas and dust in a massive star-forming region

International Nuclear Information System (INIS)

Battersby, Cara; Bally, John; Ginsburg, Adam; Darling, Jeremy; Dunham, Miranda; Longmore, Steve

2014-01-01

We explore the relationship between gas and dust in a massive star-forming region by comparing the physical properties derived from each. We compare the temperatures and column densities in a massive star-forming Infrared Dark Cloud (G32.02+0.05), which shows a range of evolutionary states, from quiescent to active. The gas properties were derived using radiative transfer modeling of the (1,1), (2,2), and (4,4) transitions of NH 3 on the Karl G. Jansky Very Large Array, while the dust temperatures and column densities were calculated using cirrus-subtracted, modified blackbody fits to Herschel data. We compare the derived column densities to calculate an NH 3 abundance, χ NH 3 = 4.6 × 10 –8 . In the coldest star-forming region, we find that the measured dust temperatures are lower than the measured gas temperatures (mean and standard deviations T dust, avg ∼ 11.6 ± 0.2 K versus T gas, avg ∼ 15.2 ± 1.5 K), which may indicate that the gas and dust are not well-coupled in the youngest regions (∼0.5 Myr) or that these observations probe a regime where the dust and/or gas temperature measurements are unreliable. Finally, we calculate millimeter fluxes based on the temperatures and column densities derived from NH 3 , which suggest that millimeter dust continuum observations of massive star-forming regions, such as the Bolocam Galactic Plane Survey or ATLASGAL, can probe hot cores, cold cores, and the dense gas lanes from which they form, and are generally not dominated by the hottest core.

Waves in strong centrifugal fields: dissipationless gas

Science.gov (United States)

Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

2015-04-01

Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

Studies of hydrogen pellet acceleration by electric arc discharge

International Nuclear Information System (INIS)

Andersen, S.

1986-01-01

A preliminary design for an arc heated gas gun is described. The experimental development of the final design constitutes the final phase in contract work for JET. The gun consist of a cryogenic arc chamber connected to the inlet of a gun barrel. With a dose of H 2 -gas condensed in the arc chamber and a D 2 -pellet punch loaded into the barrel the gun is fired by the ignition of an electrical discharge in the arc chamber. The pellet is accelerated by the exhaust of hot H 2 -gas from the arc chamber and its velocity and acceleration is measured by time-of-flight along and outside the barrel. The pressure development by the arc is monitored by pressure transducers as well in the arc chamber as in the barrel. The performance of the gun is described in terms of arc current and voltage versus time as functions of power supply configuration and H 2 propellant dose. The time behaviour of the propellant pressure in the arc chamber and in the barrel is shown in relation to the arc current. Pellet acceleration and pressure development in the gun barrel for the arc heated gas gun is discussed and compared to results obtained by conventional fast valve acceleration

In-situ strain monitoring in liquid containers of LNG transporting carriers

Science.gov (United States)

Oh, Min-Cheol; Seo, Jun-Kyu; Kim, Kyung-Jo; Lee, Sang-Min; Kim, Myung-Hyun

2008-08-01

Liquefied natural gas (LNG) transport carriers are exposed to a risk by the repeated bump in the LNG container during the vessel traveling over the wave in ocean. The liquid inside the container, especially when it was not fully contained, make a strong bump onto the insulation panel of the tank wall. The insulation panel consists of several layers of thick polyurethane foam (PUF) to maintain the LNG below the cryogenic temperature, -162°C. Due to the repeated shock on the PUF, a crack could be developed on the tank wall causing a tremendous disaster for LNG carriers. To prevent the accidental crack on the tank, a continuous monitoring of the strain imposed on the PUF is recommended. In this work, a fiber-optic Bragg grating was imbedded inside the PUF for monitoring the strain parallel to the impact direction. The optical fiber sensor with a small diameter of 125 μm was suitable to be inserted in the PUF through a small hole drilled after the PUF was cured. In-situ monitoring of the strain producing the change of Bragg reflection wavelength, a high speed wavelength interrogation method was employed by using an arrayed waveguide grating. By dropping a heavy mass on the PUF, we measured the strain imposed on the insulation panel.

Integrated modeling for optimized regional transportation with compressed natural gas fuel

Directory of Open Access Journals (Sweden)

Hossam A. Gabbar

2016-03-01

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

Acceleration of liquid by boiling of other volatile liquid, (4)

International Nuclear Information System (INIS)

Hijikata, Kunio; Mori, Yasuo

1978-01-01

In the development of liquid metal MHD power generation using liquid metal as a working fluid, it is one of the important problems to accelerate liquid metal efficiently by means of thermal energy. Though various accelerating methods have been proposed so far, those do not provide high cycle thermal efficiency because of either small electric conductivity, low accelerating efficiency or low gas-liquid separating efficiency. The authors proposed the method to accelerate through volume expansion by boiling a volatile liquid being blown into liquid metal at high temperature, and have investigated it experimentally and theoretically. In the study, efficiency has been discussed in case of the acceleration of fluid subjected to magneto-hydrodynamical force by boiling of droplets of other liquid. Theoretically, the field of flow and two-phase cycle and gas phase cycle were analyzed. The report describes on these results and discussions. It is concluded that efficiency is independent of the injected amount and position of droplets, final efficiency is little affected by external load and thermal conductivity of volatile liquid droplets, the efficiency for the combination of cesium and lead is about 50%, and the method proposed by authors seems to be better than the conventional methods with gas phase cycle proposed so far using inert gas bubbles in lieu of volatile liquid. (Wakatsuki, Y.)

A bestiary of ordinary vent activities at Stromboli (and what it tells us about vent conditions)

Science.gov (United States)

Gaudin, Damien; Taddeucci, Jacopo; Scarlato, Piergiorgio

2015-04-01

Normal active degassing at Stromboli (Aeolian Islands, Italy) is traditionally divided in two classes. Puffing correspond to the frequent (~1 Hz) release of small gas pockets (0.5 - 1 m of diameter) at low exit velocities (5 - 15 m/s). Whereas, Strombolian explosions occur at a frequency of 1 - 10 per hour, and are characterized the ejection of bombs and/or ash at high velocities (50 - 400 m/s). In order to get a broader overview of two types of degassing, we used a thermal high speed FLIR SC655 camera to monitor the temperature anomalies generated by the expelled gas, ash, and/or bombs. The enhanced time and spatial resolutions of the camera (200 frames per second, 15 cm wide pixels) enables to use numerical algorithms to distinguish and characterize individual ejection events. In particular, for each explosion and puff, we compute the temperature, the volume, the exit point and the rise velocities of the expelled material. These values, as well as the frequency of the release events, are used to portray a total of 12 vent activities, observed during three field campaigns in 2012, 2013 and 2014. Sustained puffing was visible on 7 cases, with an intensity ranging on at least two orders of magnitude. Although the released gas volume is sometimes highly variable, on some cases, constant sized puffs allows to define a typical discharge frequency ranging between 0.4 and 1.5 Hz. Regular Strombolian explosions, with various duration, intensity and ash contents, are reported in 6 cases, 2 of them simultaneously presenting a puffing activity. In some cases, we noticed modifications of the vent activity just before the explosions. These precursors, usually lasting about 1 second but occasionally reaching 10 seconds, can be sorted into 1) increase of the puffing activity ; 2) emission of gas plumes ; 3) inflation of the visible vent surface. Finally, one vent activity was hybrid between puffing and Strombolian explosions, with frequent explosions (1 Hz) ejecting numerous

Architecture of petawatt-class z-pinch accelerators

International Nuclear Information System (INIS)

Stygar, William A.; Mazarakis, Michael Gerrassimos; Cuneo, Michael Edward; Leeper, Ramon Joe; Ives, H.C.; Headley, D.I.; Wagoner, Tim C.; Porter, John Larry Jr.

2006-01-01

We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (∼1 (micro)s) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses ( 4 capacitors, store 98 MJ, and erect to 5 MV; (ii) 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii) 600 5-MV laser-triggered gas switches; (iv) three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v) a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi) six magnetically insulated vacuum transmission lines (MITLs); and (vii) a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210 LTD modules that include a total of 1 x 10 6 capacitors and 5 x 10 5 200-kV electrically triggered gas switches. The LTD accelerator stores 182 MJ and produces a peak electrical power of 1000 TW. The accelerator delivers an effective peak current of 68 MA to a pinch that implodes in 95 ns, and 75 MA to a pinch that implodes in 120 ns. Conceptually straightforward upgrades to these designs would deliver even higher pinch currents and faster implosions

Synthesis and Structure Characterization of Phenol-Urea-Formaldehyde Resins in the Presence of Magnesium Oxide as Catalyst

Directory of Open Access Journals (Sweden)

Dong-Bin Fan

2014-08-01

Full Text Available The objective of this research was to provide a useful approach of polymer synthesis for accelerating the fast cure of phenol-urea-formaldehyde (PUF resin as wood adhesive by optimizing its structure and composition. The PUF resins containing high contents of very reactive groups such as para-methylol groups were synthesized by reacting methylolurea, phenol, and formaldehyde in the presence of magnesium oxide (MgO as catalyst. The effects of synthesis parameters including F/(P + U, OH/P, and MgO/P mole ratios on the structure, composition, curing characteristics, and their relationships of PUF resins were investigated. The results indicated that MgO seemed to be an efficacious catalyst for PUF resin synthesis and promote its faster cure. The increase in the F/(P + U mole ratio or/and OH/P mole ratio appeared to be beneficial for the formation of para-methylol groups and cocondensed methylene linkages between phenolic methylol groups and urea units, and for the removal of unreacted urea. In case of Catalyst/P mole ratio, an appropriate dosage of added metal-ion was very important for synthesizing the high-content reactive groups of PUF resins, otherwise leading to the reverse effects.

Electric potential structures of auroral acceleration region border from multi-spacecraft Cluster data

Science.gov (United States)

Sadeghi, S.; Emami, M. R.

2018-04-01

This paper studies an auroral event using data from three spacecraft of the Cluster mission, one inside and two at the poleward edge of the bottom of the Auroral Acceleration Region (AAR). The study reveals the three-dimensional profile of the region's poleward boundary, showing spatial segmentation of the electric potential structures and their decay in time. It also depicts localized magnetic field variations and field-aligned currents that appear to have remained stable for at least 80 s. Such observations became possible due to the fortuitous motion of the three spacecraft nearly parallel to each other and tangential to the AAR edge, so that the differences and variations can be seen when the spacecraft enter and exit the segmentations, hence revealing their position with respect to the AAR.

The national energy policy: a case for gas

International Nuclear Information System (INIS)

Nagle, A.

2001-01-01

During the first half of 2001, Australia's Federal, State and Territory governments through COAG have dedicated considerable time to formulating their initial positions on a national energy policy. The formal development of that policy is expected to be agreed at a mid-year meeting of COAG. Given these many benefits, the AGA believes that a national energy policy should: address regulatory constraints on gas market growth and investment; ensure greenhouse programs and measures encourage fuel switching to cleaner energy sources such as natural gas; make gas market contestability regimes consistent and compatible across the States and Territories; improve and streamline project approval processes along the whole gas chain, from exploration and production through to transmission and distribution; remove regulatory structures and market rules that currently inhibit new gas entrants from entering the electricity generation and cogeneration sectors; introduce appropriate taxation regimes for long lived energy infrastructure assets, particularly following the loss of accelerated depreciation; maximise opportunities for energy choice in urban and regional areas and encourage the development, and market uptake, of new gas technologies

Laser-propelled ram accelerator

Energy Technology Data Exchange (ETDEWEB)

Sasoh, A. [Tohoku Univ., Sendai (Japan). Inst. of Fluid Science

2000-11-01

The concept of 'laser-propelled ram accelerator (L-RAMAC)' is proposed. Theoretically it is capable of achieving a higher launch speed than that by a chemical ram accelerator because a higher specific energy can be input to the propellant gas. The laser beam is supplied through the muzzle, focused as an annulus behind the base of the projectile. The performance of L-RAMAC is analized based on generalized Rankine-Hugoniot relations, suggesting that a superorbital muzzle speed is achievable out of this device. (orig.)

Particle acceleration by plasma waves

International Nuclear Information System (INIS)

Joshi, C.

2006-01-01

In an advanced particle accelerator particles are driven near by light velocity through ionized gas. Such plasma devices are compact, cost efficient and usable in many fields. Examples are given in detail. (GL)

Self-guiding of high-intensity laser pulses for laser wake field acceleration

International Nuclear Information System (INIS)

Umstader, D.; Liu, X.

1992-01-01

A means of self-guiding an ultrashort and high-intensity laser pulse is demonstrated both experimentally and numerically. Its relevance to the laser wake field accelerator concept is discussed. Self-focusing and multiple foci formation are observed when a high peak power (P>100 GW), 1 μm, subpicosecond laser is focused onto various gases (air or hydrogen). It appears to result from the combined effects of self-focusing by the gas, and de-focusing both by diffraction and the plasma formed in the central high-intensity region. Quasi-stationary computer simulations show the same multiple foci behavior as the experiments. The results suggest much larger nonlinear electronic susceptibilities of a gas near or undergoing ionization in the high field of the laser pulse. Although self-guiding of a laser beam by this mechanism appears to significantly extend its high-intensity focal region, small-scale self-focusing due to beam non-uniformity is currently a limitation

Stray-electron accumulation and effects in HIF accelerators

International Nuclear Information System (INIS)

Cohen, R.H.; Friedman, A.; Furman, M.A.; Lund, S.M.; Molvik, A.W.; Stoltz, P.; Vay, J.-L.

2003-01-01

Stray electrons can be introduced in positive-charge accelerators for heavy ion fusion (or other applications) as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. Electron accumulation is impacted by the ion beam potential, accelerating fields, multipole magnetic fields used for beam focus, and the pulse duration. We highlight the distinguishing features of heavy-ion accelerators as they relate to stray-electron issues, and present first results from a sequence of simulations to characterize the electron cloud that follows from realistic ion distributions. Also, we present ion simulations with prescribed random electron distributions, undertaken to begin to quantify the effects of electrons on ion beam quality

STRUCTURAL VARIATION OF MOLECULAR GAS IN THE SAGITTARIUS ARM AND INTERARM REGIONS

Energy Technology Data Exchange (ETDEWEB)

Sawada, Tsuyoshi; Hasegawa, Tetsuo; Sugimoto, Masahiro [Joint ALMA Office, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile); Koda, Jin [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Handa, Toshihiro, E-mail: sawada.tsuyoshi@nao.ac.jp [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)

2012-06-20

We have carried out survey observations toward the Galactic plane at l Almost-Equal-To 38 Degree-Sign in the {sup 12}CO and {sup 13}CO J = 1-0 lines using the Nobeyama Radio Observatory 45 m telescope. A wide area (0.{sup 0}8 Multiplication-Sign 0.{sup 0}8) was mapped with high spatial resolution (17''). The line of sight samples the gas in both the Sagittarius arm and the interarm regions. The present observations reveal how the structure and physical conditions vary across a spiral arm. We classify the molecular gas in the line of sight into two distinct components based on its appearance: the bright and compact B component and the fainter and diffuse (i.e., more extended) D component. The B component is predominantly seen at the spiral arm velocities, while the D component dominates at the interarm velocities and is also found at the spiral arm velocities. We introduce the brightness distribution function and the brightness distribution index (BDI, which indicates the dominance of the B component) in order to quantify the map's appearance. The radial velocities of BDI peaks coincide with those of high {sup 12}CO J = 3-2/{sup 12}CO J = 1-0 intensity ratio (i.e., warm gas) and H II regions, and tend to be offset from the line brightness peaks at lower velocities (i.e., presumably downstream side of the arm). Our observations reveal that the gas structure at small scales changes across a spiral arm: bright and spatially confined structures develop in a spiral arm, leading to star formation at the downstream side, while extended emission dominates in the interarm region.

Simulation of ion beam scattering in a gas stripper

Energy Technology Data Exchange (ETDEWEB)

Maxeiner, Sascha, E-mail: maxeiner@phys.ethz.ch; Suter, Martin; Christl, Marcus; Synal, Hans-Arno

2015-10-15

Ion beam scattering in the gas stripper of an accelerator mass spectrometer (AMS) enlarges the beam phase space and broadens its energy distribution. As the size of the injected beam depends on the acceleration voltage through phase space compression, the stripper becomes a limiting factor of the overall system transmission especially for low energy AMS system in the sub MV region. The spatial beam broadening and collisions with the accelerator tube walls are a possible source for machine background and energy loss fluctuations influence the mass resolution and thus isotope separation. To investigate the physical processes responsible for these effects, a computer simulation approach was chosen. Monte Carlo simulation methods are applied to simulate elastic two body scattering processes in screened Coulomb potentials in a (gas) stripper and formulas are derived to correctly determine random collision parameters and free path lengths for arbitrary (and non-homogeneous) gas densities. A simple parametric form for the underlying scattering cross sections is discussed which features important scaling behaviors. An implementation of the simulation was able to correctly model the data gained with the TANDY AMS system at ETH Zurich. The experiment covered transmission measurements of uranium ions in helium and beam profile measurements after the ion beam passed through the He-stripper. Beam profiles measured up to very high stripper densities could be understood in full system simulations including the relevant ion optics. The presented model therefore simulates the fundamental physics of the interaction between an ion beam and a gas stripper reliably. It provides a powerful and flexible tool for optimizing existing AMS stripper geometries and for designing new, state of the art low energy AMS systems.

The regional economic impact of oil and gas extraction in Texas

International Nuclear Information System (INIS)

Lee, Jim

2015-01-01

This paper empirically investigates the regional economic impact of oil and gas extraction in Texas during the recent shale oil boom. Regressions with county-level data over the period 2009–2014 support smaller multiplier effects on local employment and income than corresponding estimates drawn from popular input–output-based studies. Economic impacts were larger for extraction from gas wells than oil wells, while the drilling phase generated comparable impacts. Estimates of economic impacts are greater in a dynamic spatial panel model that allows for spillover effects across local economies as well as over time. - Highlights: • Economic impacts and multiplier effects differ between oil and gas wells in Texas. • Interactions among local economies raise employment and income effects. • Impacts persist over time, raising the long-run multipliers. • Greater economic impacts from newly drilled wells than legacy wells.

Plasma acceleration by means of microwave radiation pressure

International Nuclear Information System (INIS)

Fukumura, Takashi; Takamoto, Teruo

1977-01-01

In the electric discharge of gas with microwaves, intense reflection waves occur simultaneously with the discharge, so the plasma ionized and formed by the microwaves is accelerated due to large radiation pressure. The basic experiment made, aiming at plasma gun, is described. In the gas electric discharge, the plasma flow velocity proportional to the reflected power is obtained. For 550 W microwave input power, the plasma velocity of 1 x 10 4 m/s was obtained. The accelerated plasma is bunched; its front as mass travels, recombines and disappears. (Mori, K.)

Associations between accelerated glacier mass wastage and increased summer temperature in coastal regions

Science.gov (United States)

Dyurgerov, M.; McCabe, G.J.

2006-01-01

Low-elevation glaciers in coastal regions of Alaska, the Canadian Arctic, individual ice caps around the Greenland ice sheet, and the Patagonia Ice Fields have an aggregate glacier area of about 332 ?? 103 km 2 and account for approximately 42% of all the glacier area outside the Greenland and Antarctic ice sheets. They have shown volume loss, especially since the end of the 1980s, increasing from about 45% in the 1960s to nearly 67% in 2003 of the total wastage from all glaciers on Earth outside those two largest ice sheets. Thus, a disproportionally large contribution of coastal glacier ablation to sea level rise is evident. We examine cumulative standardized departures (1961-2000 reference period) of glacier mass balances and air temperature data in these four coastal regions. Analyses indicate a strong association between increases in glacier volume losses and summer air temperature at regional and global scales. Increases in glacier volume losses in the coastal regions also coincide with an accelerated rate of ice discharge from outlet glaciers draining the Greenland and West Antarctic ice sheets. These processes imply further increases in sea level rise. ?? 2006 Regents of the University of Colorado.

Development of bipolar-pulse accelerator for intense pulsed ion beam acceleration

Energy Technology Data Exchange (ETDEWEB)

Masugata, Katsumi [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: masugata@eng.toyama-u.ac.jp; Shimizu, Yuichro [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Fujioka, Yuhki [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Kitamura, Iwao [Department of Electrical and Electronic System Engineering, Toyama University, 3190 Gofuku, Toyama 930-8555 (Japan); Tanoue, Hisao [National Institute of Advanced Industry Science and Technology, 1-1-1, Umezono, Tsukuba-shi, Ibaraki 305-8568 (Japan); Arai, Kazuo [National Institute of Advanced Industry Science and Technology, 1-1-1, Umezono, Tsukuba-shi, Ibaraki 305-8568 (Japan)

2004-12-21

To improve the purity of intense pulsed ion beams, a new type of pulsed ion beam accelerator named 'bipolar pulse accelerator' was proposed. To confirm the principle of the accelerator a prototype of the experimental system was developed. The system utilizes By type magnetically insulated acceleration gap and operated with single polar negative pulse. A coaxial gas puff plasma gun was used as an ion source, which was placed inside the grounded anode. Source plasma (nitrogen) of current density {approx}25A/cm2, duration {approx}1.5{mu}s was injected into the acceleration gap by the plasma gun. The ions were successfully accelerated from the grounded anode to the drift tube by applying negative pulse of voltage 240kV, duration 100ns to the drift tube. Pulsed ion beam of current density {approx}40A/cm2, duration {approx}50ns was obtained at 41mm downstream from the anode surface. To evaluate the irradiation effect of the ion beam to solid material, an amorphous silicon thin film of thickness {approx}500nm was used as the target, which was deposited on the glass substrate. The film was found to be poly-crystallized after 4-shots of the pulsed nitrogen ion beam irradiation.

Towards polarization measurements of laser-accelerated helium-3 ions

Energy Technology Data Exchange (ETDEWEB)

Engin, Ilhan

2015-08-28

In the framework of this thesis, preparatory investigations for the spin-polarization measurement of {sup 3}He ions from laser-induced plasmas have been performed. Therefore, experiments aiming at an efficient laser-induced ion acceleration out of a {sup 4}He gas target were carried out at two high-intensity laser facilities: the Arcturus laser at Heinrich-Heine-Universitaet Duesseldorf as well as PHELIX at GSI Darmstadt. The scientific goal of both experiments was to investigate the ion-acceleration process in underdense plasmas by measuring the ion energy spectra and the angular distribution of the ion signal around the gas-jet target. Laser-accelerated MeV-He-ions could successfully be detected. The main acceleration direction at large angles with regard to the laser propagation direction was determined. In a second step, unpolarized {sup 3}He gas was attached in order to cross-check the experimental results with those of {sup 4}He. With the help of the achieved ion yield data, the expected rates of the fusion reaction D({sup 3}He,p){sup 4}He in the polarized case have been estimated: the information regarding the fusion proton yield from this nuclear reaction allows an experimentally based estimation for future experiments with pre-polarized {sup 3}He gas as plasma target. The experimental data is in line with supporting Particle-in-Cell (PIC) simulations performed on the Juelich supercomputers. For this purpose, the simulated target was defined as a neutral gas. The use of pre-polarized {sup 3}He gas demands a special preparation of a polarized {sup 3}He target for laser-acceleration experiments. This layout includes an (external) homogeneous magnetic holding field (field strength of ∝1.4 mT) for storing the pre-polarized gas for long time durations inside the PHELIX target chamber. For this purpose, a precise Halbach array consisting of horizontally arranged rings with built-in permanent magnets had to be designed, optimized, and constructed to deliver high

Acceleration of Vaporization, Atomization, and Ionization Efficiencies in Inductively Coupled Plasma by Merging Laser-Ablated Particles with Hydrochloric Acid Gas.

Science.gov (United States)

Nakazawa, Takashi; Izumo, Saori; Furuta, Naoki

2016-01-01

To accelerate the vaporization, atomization, and ionization efficiencies in laser ablation inductively coupled plasma mass spectrometry, we merged HCl gas with laser-ablated particles before introduction into the plasma, to convert their surface constituents from oxides to lower-melting chlorides. When particles were merged with HCl gas generated from a HCl solution at 200°C, the measured concentrations of elements in the particles were 135% higher on average than the concentrations in particles merged with ultrapure water vapor. Particle corrosion and surface roughness were observed by scanning electron microscopy, and oxide conversion to chlorides was confirmed by X-ray photoelectron spectroscopy. Under the optimum conditions, the recoveries of measured elements improved by 23% on average, and the recoveries of elements with high-melting oxides (Sr, Zr, and Th) improved by as much as 36%. These results indicate that vaporization, atomization, and ionization in the ICP improved when HCl gas was merged with the ablated particles.

Spatially inhomogeneous acceleration of electrons in solar flares

Science.gov (United States)

Stackhouse, Duncan J.; Kontar, Eduard P.

2018-04-01

The imaging spectroscopy capabilities of the Reuven Ramaty high energy solar spectroscopic imager (RHESSI) enable the examination of the accelerated electron distribution throughout a solar flare region. In particular, it has been revealed that the energisation of these particles takes place over a region of finite size, sometimes resolved by RHESSI observations. In this paper, we present, for the first time, a spatially distributed acceleration model and investigate the role of inhomogeneous acceleration on the observed X-ray emission properties. We have modelled transport explicitly examining scatter-free and diffusive transport within the acceleration region and compare with the analytic leaky-box solution. The results show the importance of including this spatial variation when modelling electron acceleration in solar flares. The presence of an inhomogeneous, extended acceleration region produces a spectral index that is, in most cases, different from the simple leaky-box prediction. In particular, it results in a generally softer spectral index than predicted by the leaky-box solution, for both scatter-free and diffusive transport, and thus should be taken into account when modelling stochastic acceleration in solar flares.

Emissions implications of future natural gas production and use in the U.S. and in the Rocky Mountain region.

Science.gov (United States)

McLeod, Jeffrey D; Brinkman, Gregory L; Milford, Jana B

2014-11-18

Enhanced prospects for natural gas production raise questions about the balance of impacts on air quality, as increased emissions from production activities are considered alongside the reductions expected when natural gas is burned in place of other fossil fuels. This study explores how trends in natural gas production over the coming decades might affect emissions of greenhouse gases (GHG), volatile organic compounds (VOCs) and nitrogen oxides (NOx) for the United States and its Rocky Mountain region. The MARKAL (MARKet ALlocation) energy system optimization model is used with the U.S. Environmental Protection Agency's nine-region database to compare scenarios for natural gas supply and demand, constraints on the electricity generation mix, and GHG emissions fees. Through 2050, total energy system GHG emissions show little response to natural gas supply assumptions, due to offsetting changes across sectors. Policy-driven constraints or emissions fees are needed to achieve net reductions. In most scenarios, wind is a less expensive source of new electricity supplies in the Rocky Mountain region than natural gas. U.S. NOx emissions decline in all the scenarios considered. Increased VOC emissions from natural gas production offset part of the anticipated reductions from the transportation sector, especially in the Rocky Mountain region.

Developing the market for natural gas and biogas as a vehicle fuel on a regional level (MADEGASCAR)

Energy Technology Data Exchange (ETDEWEB)

Emmerling, Bettina; Jellinek, Reinhard (Austrian Energy Agency (Austria)); Baumgartner, Birgit (Graz Energy Agency, Graz (Austria))

2009-07-01

Although natural gas as a car fuel is a more environmentally clean alternative to gasoline or diesel and gas is considerable cheaper and much safer than other fuels, costumers are still suspicious of alternative fuels and vehicles. The main reasons are a lack of awareness and information on the consumer side, as well as a low information and acceptance level among car dealers and service stations. Therefore the MADEGASCAR project directly addresses major barriers by specific actions. The project MADEGASCAR (Market development for gas driven cars including supply and distribution of biogas), co-funded by the Intelligent Energy Europe programme of the European commission, aims at developing the market for natural gas vehicles by addressing target groups at the demand side (private car owners, fleet managers) as well as strengthening the supply and distribution infrastructure for Compressed Natural Gas (CNG) and Natural Gas Vehicles (NGVs) municipalities, car dealers, owners of fuel stations, natural gas and biogas suppliers) in 10 participating partner countries. The Unique Selling Point of the MADEGASCAR project is deployment in several regional areas instead of sole basic research. Country specific action plans, which are developed and implemented in the project, will have direct impact on regional markets but also affect car manufacturers and national regulations, resulting in long term changes. The main ambition of the MADEGASCAR project is to increase the number of gas vehicles in the partner regions by 50%.

Russia's natural gas policy toward Northeast Asia: Rationales, objectives and institutions

International Nuclear Information System (INIS)

Shadrina, Elena

2014-01-01

The article examines the institutional dimensions of Russia's gas policy toward Northeast Asia (NEA During the liberal economic reforms of the 1990s, development of natural gas deposits in the Russian Far East was made possible under the scheme of production sharing agreements (PSA). However, new PSAs were banned in Russia even before the advent of state capitalism in the early 2000s. This was, to a large extent, the result of strong anti-PSA lobbying led by the domestic energy business elite. Consequently, Russia's gas policy in the east began evolving from being project-specific toward being region-specific. Contemporary Russian gas policy toward NEA relies upon domestic (national and regional) and external institutions. In 2009, following the completion of a liquefied natural gas (LNG) plant in Sakhalin, Russia entered NEA gas markets. Transformations in the international gas markets facilitated the establishment of a two-pattern gas export policy in Russia in 2013. Under this policy, Russia's EU-oriented pipeline gas export remains monopolised by Gazprom, while Asia-oriented LNG export is partially liberalised. Russia has not been experiencing institutional discrepancy in NEA gas markets. However, as the markets evolve toward greater coordination, a rational option for Russia is to genuinely liberalise its gas policy. - Highlights: • Russia–EU institutional inconsistency has accelerated Russia's gas export diversification. • Institutions for regional development are an important component of Russia's gas policy in Asia. • Transformations in globalising gas markets induced Russia's limited gas export liberalisation. • Genuine gas policy liberalisation can facilitate the attainment of Russia's goals in Asia

Plasma production for electron acceleration by resonant plasma wave

International Nuclear Information System (INIS)

Anania, M.P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Di Pirro, G.P.; Filippi, F.; Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R.; Romeo, S.; Ferrario, M.

2016-01-01

Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10–100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10–100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

Plasma production for electron acceleration by resonant plasma wave

Energy Technology Data Exchange (ETDEWEB)

Anania, M.P., E-mail: maria.pia.anania@lnf.infn.it [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Biagioni, A.; Chiadroni, E. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Cianchi, A. [University of Rome Tor Vergata - INFN, via della Ricerca Scientifica, 1, 00133 Roma (Italy); INFN, Via della Ricerca Scientifica, 1, 00133 Roma (Italy); Croia, M.; Curcio, A. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Di Giovenale, D.; Di Pirro, G.P. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Filippi, F. [University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Romeo, S. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ferrario, M. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy)

2016-09-01

Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10–100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10–100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

Particle Acceleration in Multiple Dissipation Regions

OpenAIRE

Arzner, Kaspar; Vlahos, Loukas

2004-01-01

The sharp magnetic discontinuities which naturally appear in solar magnetic flux tubes driven by turbulent photospheric motions are associated with intense currents. \\citet{Par83} proposed that these currents can become unstable to a variety of microscopic processes, with the net result of dramatically enhanced resistivity and heating (nanoflares). The electric fields associated with such ``hot spots'' are also expected to enhance particle acceleration. We test this hypothesis by exact relati...

Flue gas corrosion through halogen compounds in fuel gas

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, R

1987-04-01

The halogens of chlorine and fluorine greatly influence the corrosion speed of metal materials. If small quantities of chlorinated and/or fluorinated hydrocarbons are present in fuel gas like in landfill gas, they must not result in enhanced corrosion of gas appliances. Data from literature and the initial results of tests run by the author indicate that quantities at about 10 mg/cbm (in terms of chlorine) can be assumed not to cause any noticeable acceleration of corrosion speed.

Acidic sweep gas with carbonic anhydrase coated hollow fiber membranes synergistically accelerates CO2 removal from blood.

Science.gov (United States)

Arazawa, D T; Kimmel, J D; Finn, M C; Federspiel, W J

2015-10-01

The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal from blood in model gas exchange devices by converting bicarbonate to CO2 directly at the HFM surface. This present study tested the hypothesis that dilute sulfur dioxide (SO2) in oxygen sweep gas could further increase CO2 removal by creating an acidic microenvironment within the diffusional boundary layer adjacent to the HFM surface, facilitating dehydration of bicarbonate to CO2. CA was covalently immobilized onto poly (methyl pentene) (PMP) HFMs through glutaraldehyde activated chitosan spacers, potted in model gas exchange devices (0.0151 m(2)) and tested for CO2 removal rate with oxygen (O2) sweep gas and a 2.2% SO2 in oxygen sweep gas mixture. Using pure O2 sweep gas, CA-PMP increased CO2 removal by 31% (258 mL/min/m(2)) compared to PMP (197 mL/min/m(2)) (Premoval by 17% (230 mL/min/m(2)) compared to pure oxygen sweep gas control (Premoval increased by 109% (411 mL/min/m(2)) (Premoval, and when used in combination with bioactive CA-HFMs has a synergistic effect to more than double CO2 removal while maintaining physiologic pH. Through these technologies the next generation of intravascular and paracorporeal respiratory assist devices can remove more CO2 with smaller blood contacting surface areas. A clinical need exists for more efficient respiratory assist devices which utilize low blood flow rates (removal efficiency by shifting equilibrium from bicarbonate to gaseous CO2, through either a bioactive carbonic anhydrase enzyme coating or bulk blood acidification with lactic acid. In this study we demonstrate a novel approach to local blood acidification using an acidified sweep gas in combination with a bioactive coating to more than double CO2 removal

Occurrence and gas/particle partitioning of short- and medium-chain chlorinated paraffins in the atmosphere of Fildes Peninsula of Antarctica

Science.gov (United States)

Ma, Xindong; Zhang, Haijun; Zhou, Hongqiang; Na, Guangshui; Wang, Zhen; Chen, Chen; Chen, Jingwen; Chen, Jiping

2014-06-01

Chlorinated paraffins (CPs) were measured in air samples at a remote air monitoring site established in Georgia King Island, Fildes Peninsula of Antarctica (Great Wall Station, China) to study the long-range atmospheric transport of these anthropogenic pollutants to the Antarctic. Gas- and particle-phase CPs were collected using polyurethane foam plugs (PUF) and glass fiber filters (GFF) respectively during summertime of 2012. The total atmospheric levels of SCCPs and MCCPs ranged from 9.6 to 20.8 pg m-3 (average: 14.9 pg m-3) and 3.7-5.2 pg m-3 (average: 4.5 pg m-3), respectively. C10 and C11 carbon chain homologues with Cl5 and Cl6 chlorine atoms predominated in SCCP formula groups both in gas- and particle-phase. Significant linear correlation was found between gas/particle partition coefficients (KP) and sub-cooled liquid vapor pressures (pL°) (R2 = 0.437, p chlorinated CPs and overestimate the sorption of highly chlorinated CPs.

ACFA and IPAC announce accelerator prizes

CERN Multimedia

CERN Bulletin

2010-01-01

Steve Myers, CERN's Director for Accelerators and Technology. The Asian Committee for Future Accelerators (ACFA) has joined forces with the first International Particle Accelerator Conference, IPAC’10, to award prizes for outstanding work in the field of accelerators. The conference replaces the regional conferences of the Americas, Europe and Asia and will be hosted by the three regions on a rotational basis (see CERN Courier). The ACFA/IPAC’10 Prizes Selection Committee, chaired by Won Namkung of Pohang Accelerator Laboratory, decided on the prizes and the names of the winners at a meeting on 20 January. The awards will be made during IPAC’10, which will be held in Kyoto on 23-28 May. Jie Wei. (Courtesy Tsinghua University.) Steve Myers, Director for Accelerators and Technology at CERN, receives an Achievement Prize for Outstanding Work in the Accelerator Field with no Age Limit “for his numerous outstanding contributions to the design, construction, commissio...

Plasma-focused cyclic accelerators

International Nuclear Information System (INIS)

Mondelli, A.A.; Chernin, D.P.

1985-01-01

The use of ambient plasma to neutralize the transverse forces of an intense particle beam has been known for many years. Most recently, the so-called ion-focused regime (IFR) for beam propagation has been used as a means of focusing intense electron beams in linear accelerators and suggested for injecting an electron beam across magnetic field lines into a high-current cyclic accelerator. One technique for generating the required background plasma for IFR propagation is to use a laser to ionize ambient gas in the accelerator chamber. For cyclic accelerators a technique is required for carrying the plasma channel and the beam around a bend. Multiple laser-generated channels with dipole magnetic fields to switch the beam from one channel to the next have been tested at Sandia. This paper discusses an alternative means of plasma production for IFR, viz. by using rf breakdown. For this approach the accelerator chamber acts as a waveguide. With a suitable driving frequency, a waveguide mode can be driven which has its peak field intensity on the axis with negligible fields at the chamber walls. The plasma production and hence the beam propagation is thereby isolated from the walls. This technique is not limited to toroidal accelerators. It may be applied to any accelerator or recirculator geometry as well as for beam steering and for injection or extraction of beams in closed accelerator configurations

Estimation of peak heat flux onto the targets for CFETR with extended divertor leg

International Nuclear Information System (INIS)

Zhang, Chuanjia; Chen, Bin; Xing, Zhe; Wu, Haosheng; Mao, Shifeng; Luo, Zhengping; Peng, Xuebing; Ye, Minyou

2016-01-01

Highlights: • A hypothetical geometry is assumed to extend the outer divertor leg in CFETR. • Density scan SOLPS simulation is done to study the peak heat flux onto target. • Attached–detached regime transition in out divertor occurs at lower puffing rate. • Unexpected delay of attached–detached regime transition occurs in inner divertor. - Abstract: China Fusion Engineering Test Reactor (CFETR) is now in conceptual design phase. CFETR is proposed as a good complement to ITER for demonstrating of fusion energy. Divertor is a crucial component which faces the plasmas and handles huge heat power for CFETR and future fusion reactor. To explore an effective way for heat exhaust, various methods to reduce the heat flux to divertor target should be considered for CFETR. In this work, the effect of extended out divertor leg on the peak heat flux is studied. The magnetic configuration of the long leg divertor is obtained by EFIT and Tokamak Simulation Code (TSC), while a hypothetical geometry is assumed to extend the out divertor leg as long as possible inside vacuum vessel. A SOLPS simulation is performed to study peak heat flux of the long leg divertor for CFETR. D 2 gas puffing is used and increasing of the puffing rate means increase of plasma density. Both peak heat flux onto inner and outer targets are below 10 MW/m 2 is achieved. A comparison between the peak heat flux between long leg and conventional divertor shows that an attached–detached regime transition of out divertor occurs at lower gas puffing gas puffing rate for long leg divertor. While for the inner divertor, even the configuration is almost the same, the situation is opposite.

Estimation of peak heat flux onto the targets for CFETR with extended divertor leg

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chuanjia; Chen, Bin [School of Nuclear Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Xing, Zhe [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wu, Haosheng [School of Nuclear Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Mao, Shifeng, E-mail: sfmao@ustc.edu.cn [School of Nuclear Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Luo, Zhengping; Peng, Xuebing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Ye, Minyou [School of Nuclear Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2016-11-01

Highlights: • A hypothetical geometry is assumed to extend the outer divertor leg in CFETR. • Density scan SOLPS simulation is done to study the peak heat flux onto target. • Attached–detached regime transition in out divertor occurs at lower puffing rate. • Unexpected delay of attached–detached regime transition occurs in inner divertor. - Abstract: China Fusion Engineering Test Reactor (CFETR) is now in conceptual design phase. CFETR is proposed as a good complement to ITER for demonstrating of fusion energy. Divertor is a crucial component which faces the plasmas and handles huge heat power for CFETR and future fusion reactor. To explore an effective way for heat exhaust, various methods to reduce the heat flux to divertor target should be considered for CFETR. In this work, the effect of extended out divertor leg on the peak heat flux is studied. The magnetic configuration of the long leg divertor is obtained by EFIT and Tokamak Simulation Code (TSC), while a hypothetical geometry is assumed to extend the out divertor leg as long as possible inside vacuum vessel. A SOLPS simulation is performed to study peak heat flux of the long leg divertor for CFETR. D{sub 2} gas puffing is used and increasing of the puffing rate means increase of plasma density. Both peak heat flux onto inner and outer targets are below 10 MW/m{sup 2} is achieved. A comparison between the peak heat flux between long leg and conventional divertor shows that an attached–detached regime transition of out divertor occurs at lower gas puffing gas puffing rate for long leg divertor. While for the inner divertor, even the configuration is almost the same, the situation is opposite.

Study of diffuse H II regions potentially forming part of the gas streams around Sgr A*

Science.gov (United States)

Armijos-Abendaño, J.; López, E.; Martín-Pintado, J.; Báez-Rubio, A.; Aravena, M.; Requena-Torres, M. A.; Martín, S.; Llerena, M.; Aldás, F.; Logan, C.; Rodríguez-Franco, A.

2018-05-01

We present a study of diffuse extended ionized gas towards three clouds located in the Galactic Centre (GC). One line of sight (LOS) is towards the 20 km s-1 cloud (LOS-0.11) in the Sgr A region, another LOS is towards the 50 km s-1 cloud (LOS-0.02), also in Sgr A, while the third is towards the Sgr B2 cloud (LOS+0.693). The emission from the ionized gas is detected from Hnα and Hmβ radio recombination lines (RRLs). Henα and Hemβ RRL emission is detected with the same n and m as those from the hydrogen RRLs only towards LOS+0.693. RRLs probe gas with positive and negative velocities towards the two Sgr A sources. The Hmβ to Hnα ratios reveal that the ionized gas is emitted under local thermodynamic equilibrium conditions in these regions. We find a He to H mass fraction of 0.29±0.01 consistent with the typical GC value, supporting the idea that massive stars have increased the He abundance compared to its primordial value. Physical properties are derived for the studied sources. We propose that the negative velocity component of both Sgr A sources is part of gas streams considered previously to model the GC cloud kinematics. Associated massive stars with what are presumably the closest H II regions to LOS-0.11 (positive velocity gas), LOS-0.02, and LOS+0.693 could be the main sources of ultraviolet photons ionizing the gas. The negative velocity components of both Sgr A sources might be ionized by the same massive stars, but only if they are in the same gas stream.

[Accelerator physics R ampersand D

International Nuclear Information System (INIS)

Krisch, A.D.

1994-01-01

This report discusses the NEPTUN-A experiment that will study spin effects in violent proton-proton collisions; the Siberian snake tests at IUCF cooler ring; polarized gas jets; and polarized proton acceleration to 1 TeV at Fermilab

Acceleration waves in non-ideal magnetogasdynamics

Directory of Open Access Journals (Sweden)

R. Singh

2014-03-01

Full Text Available The problem of propagation of acceleration waves in an unsteady inviscid non-ideal gas under the influence of magnetic field is investigated. The characteristic solution to the problem in the neighbourhood of leading characteristics has been determined. An evolution equation governing the behaviour of acceleration waves has been derived. It is shown that a linear solution in the characteristic plane exhibits non-linear behaviour in physical plane. The effect of magnetic field on the formation of shock in non-ideal gas flow with planar and cylindrical symmetry is analysed. It is noticed that all compressive waves terminate into a shock wave. Further, we also compare/contrast the nature of solution in ideal and non-ideal magnetogasdynamic regime.

Entrepreneurial Leadership in Upstream Oil and Gas Industry

OpenAIRE

Kalu, Mona Ukpai

2015-01-01

The study examined Entrepreneurial leadership in Upstream Oil and Gas industry and its ability to accelerate innovative energy technology development. The declining deliverability from existing reservoirs and ever increasing demand for energy to fuel growth in many parts of the world is driving oil and gas exploration into more difficult to access reservoirs like bituminous sands and shale gas. Accelerating new innovative technology development to access these new streams of profitable oil an...

Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator.

Science.gov (United States)

Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki

2016-02-01

To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator

Energy Technology Data Exchange (ETDEWEB)

Hiratsuka, Junichi, E-mail: hiratsuka.junichi@jaea.go.jp; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan); Miyamoto, Kenji [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)

2016-02-15

To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

DNA sequence analysis of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T

OpenAIRE

Choudhary, M.; Kaplan, Samuel

2000-01-01

This paper describes the DNA sequence of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T. The photosynthesis gene cluster is located within a ~73 kb AseI genomic DNA fragment containing the puf, puhA, cycA and puc operons. A total of 65 open reading frames (ORFs) have been identified, of which 61 showed significant similarity to genes/proteins of other organisms while only four did not reveal any significant sequence similarity to any gene/protein sequences in the database. The da...

Advanced cost-effective surface geochemical techniques for oil/gas/uranium exploration, environmental assessments and pipeline monitoring - a template for India

International Nuclear Information System (INIS)

Lafleur, Paul; Chanrasekharan, G.Y.V.N.; Rajender Rao, S.

2011-01-01

Advanced geochemical soil gas methods have been successfully developed for the exploration of oil/gas/uranium and for environmental assessments. Application of these cost-effective technologies in India can substantially reduce exploration risk while accelerating the development of oil/gas/uranium onshore resources. A reliable and effective monitoring system using geochemical soil gas surveys ensures that CO 2 Enhanced Oil Recovery operations as well as CO 2 sequestration projects are safe and acceptable for the disposal of CO 2 , Soil gas surveys along with other technologies can also be applied for monitoring of oil/gas pipelines for leakage, especially those that are old or pass through populated regions

Accelerating transition dynamics in city regions: A qualitative modeling perspective

NARCIS (Netherlands)

P.J. Valkering (Pieter); Yücel, G. (Gönenç); Gebetsroither-Geringer, E. (Ernst); Markvica, K. (Karin); Meynaerts, E. (Erika); N. Frantzeskaki (Niki)

2017-01-01

textabstractIn this article, we take stock of the findings from conceptual and empirical work on the role of transition initiatives for accelerating transitions as input for modeling acceleration dynamics. We applied the qualitative modeling approach of causal loop diagrams to capture the dynamics

Effects of Absorbing Aerosols on Accelerated Melting of Snowpack in the Hindu-Kush-Himalayas-Tibetan Plateau Region

Science.gov (United States)

Lau, William K.; Kyu-Myong, Kim; Yasunari, Teppei; Gautam, Ritesh; Hsu, Christina

2011-01-01

The impacts of absorbing aerosol on melting of snowpack in the Hindu-Kush-Himalayas-Tibetan Plateau (HKHT) region are studied using in-situ, satellite observations, and GEOS-5 GCM. Based on atmospheric black carbon measurements from the Pyramid observation ( 5 km elevation) in Mt. Everest, we estimate that deposition of black carbon on snow surface will give rise to a reduction in snow surface albedo of 2- 5 %, and an increased annual runoff of 12-34% for a typical Tibetan glacier. Examination of satellite reflectivity and re-analysis data reveals signals of possible impacts of dust and black carbon in darkening the snow surface, and accelerating spring melting of snowpack in the HKHT, following a build-up of absorbing aerosols in the Indo-Gangetic Plain. Results from GCM experiments show that 8-10% increase in the rate of melting of snowpack over the western Himalayas and Tibetan Plateau can be attributed to the elevated-heat-pump (EHP) feedback effect, initiated from the absorption of solar radiation by dust and black carbon accumulated to great height ( 5 km) over the Indo-Gangetic Plain and Himalayas foothills in the pre-monsoon season (April-May). The accelerated melting of the snowpack is enabled by an EHP-induced atmosphere-land-snowpack positive feedback involving a) orographic forcing of the monsoon flow by the complex terrain, and thermal forcing of the HKHT region, leading to increased moisture, cloudiness and rainfall over the Himalayas foothills and northern India, b) warming of the upper troposphere over the Tibetan Plateau, and c) an snow albedo-temperature feedback initiated by a transfer of latent and sensible heat from a warmer atmosphere over the HKHT to the underlying snow surface. Results from ongoing modeling work to assess the relative roles of EHP vs. snow-darkening effects on accelerated melting of snowpack in HKHT region will also be discussed.

LINEAR ACCELERATOR

Science.gov (United States)

Christofilos, N.C.; Polk, I.J.

1959-02-17

Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

A system for monitoring the radiation effects of a proton linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Skorkin, V. M., E-mail: skorkin@inr.ru; Belyanski, K. L.; Skorkin, A. V. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2016-12-15

The system for real-time monitoring of radioactivity of a high-current proton linear accelerator detects secondary neutron emission from proton beam losses in transport channels and measures the activity of radionuclides in gas and aerosol emissions and the radiation background in the environment affected by a linear accelerator. The data provided by gamma, beta, and neutron detectors are transferred over a computer network to the central server. The system allows one to monitor proton beam losses, the activity of gas and aerosol emissions, and the radiation emission level of a linear accelerator in operation.

Accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator. PD-1-2

International Nuclear Information System (INIS)

Bhagwat, P.V.

2007-01-01

Accelerator mass spectrometry (AMS) is an ultra sensitive means of counting individual atoms having sufficiently long half-life and available in small amount. The 14 UD Pelletron Accelerator is an ideal machine to carry out AMS studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radioisotope 36 Cl is widely being detected using AMS as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc . The AMS programme at the 14 UD Mumbai Pelletron Accelerator has taken off with the installation of the state of the art Terminal Potential Stabilizer setup and operation of the accelerator in Generating Volt Meter (GVM) mode. Feasibility studies have been carried out for detection/identification of 14 C from a charcoal sample and 3 He in natural Helium. As the primary interest of AMS programme at Mumbai Pelletron Accelerator is related to the cosmogenic nuclei, 36 Cl and 129 I, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has also been developed

Development of innovative fuelling systems for fusion energy science

International Nuclear Information System (INIS)

Gouge, M.J.; Baylor, L.R.; Combs, S.K.; Fisher, P.W.

1996-01-01

The development of innovative fueling systems in support of magnetic fusion energy, particularly the International Thermonuclear Experimental Reactor (ITER), is described. The ITER fuelling system will use a combination of deuterium-tritium (D-T) gas puffing and pellet injection to achieve and maintain ignited plasmas. This combination will provide a flexible fuelling source with D-T pellets penetrating beyond the separatrix to sustain the ignited fusion plasma and with deuterium-rich gas fuelling the edge region to meet divertor requirements in a process called isotopic fuelling. More advanced systems with potential for deeper penetration, such as multistage pellet guns and compact toroid injection, are also described

Experimental study of CF4 conical theta pinch plasma expanding into vacuum

International Nuclear Information System (INIS)

Pedrow, P.D.; Nasiruddin, A.M.

1989-01-01

Langmuir probe, photodiode, and optical multichannel analyzer (OMA) measurements have been made on a pulsed CF 4 conical theta pinch plasma. A cloud of CF 4 gas was puffed into a conical theta pinch coil, converted to plasma, and propelled into the vacuum region ahead of the expanding gas cloud. At a position 67 cm away from the conical theta pinch coil, the plasma arrived in separate packets that were about 20 μs in duration. The average drift velocity of these packets corresponded to an energy of about 3 eV. The OMA measurements showed that the second packet contained neutral atomic fluorine as well as charged particles

The place of the Irish Sea oil and gas industryin the economy of the region

International Nuclear Information System (INIS)

Stoney, P.J.M.

1995-01-01

The economies of two areas close to the Irish Sea, Morecambe Bay and Liverpool Bay, are compared in order to illustrate the effect of the Irish Sea oil and gas industry on these regions. Capital investment projects connected with those industries during the construction and operational lifetime periods are considered in terms of direct, indirect and induced effects. Mathematical modelling is used to provide a conceptual basis for making inferences about the possible size of oil and gas industry effects on local economies. Information on employment in various regions and sectors of industry, including forecasts of future profitability are given. (UK)

Advanced Accelerator Applications University Participation Program

International Nuclear Information System (INIS)

Chen, Y.; Hechanova, A.

2007-01-01

Our research tasks span the range of technology areas for transmutation, gas-cooled reactor technology, and high temperature heat exchangers, including separation of actinides from spent nuclear fuel, methods of fuel fabrication, reactor-accelerator coupled experiments, corrosion of materials exposed to lead-bismuth eutectic, and special nuclear materials protection and accountability. In the six years of this program, we saw the evolution of the national transmutation concepts go from the use of accelerators to fast reactors. We also saw an emphasis on gas-cooled reactors for both high temperature heat and deep burn of nuclear fuel. At the local level, we saw a great birth at UNLV of two new academic programs Fall term of 2004 and the addition of 10 academic and research faculty. The Ph.D. program in Radiochemistry has turned into one of the nation's most visible and successful programs; and, the M.S. program in Materials and Nuclear Engineering initiated Nuclear Engineering academic opportunities which took a long time to come. Our research tasks span the range of technology areas for transmutation, gas-cooled reactor technology, and high temperature heat exchangers, including separation of actinides from spent nuclear fuel, methods of fuel fabrication, reactor-accelerator coupled experiments, corrosion of materials exposed to lead-bismuth eutectic, and special nuclear materials protection and accountability

Relativistic shocks and particle acceleration

International Nuclear Information System (INIS)

Heavens, A.F.

1988-01-01

In this paper, we investigate the fluid dynamics of relativistic shock waves, and use the results to calculate the spectral index of particles accelerated by the Fermi process in such shocks. We have calculated the distributions of Fermi-accelerated particles at shocks propagating into cold proton-electron plasma and also cold electron-positron plasma. We have considered two different power spectra for the scattering waves, and find, in contrast to the non-relativistic case, that the spectral index of the accelerated particles depends on the wave power spectrum. On the assumption of thermal equilibrium both upstream and downstream, we present some useful fits for the compression ratio of shocks propagating at arbitrary speeds into gas of any temperature. (author)

Regional specific mean expiratory gas flow from Slmsub(Kr) equilibrium inhalation data

International Nuclear Information System (INIS)

Hamilton, D.; Causer, D.A.; McIntosh, J.A.; Godfrey, K.R.

1985-01-01

A new method of analysing the data available from routine sup(81m) Kr equilibrium inhalation investigations has been developed. The data for analysis are acquired from a gamma camera in the form of a sequential series of images from which multiple breath activity-time curves are generated for eight regions in the lung. The method is based on a description of the behaviour of the radioactive gas in the lung using a mathematical model. Values of specific mean expiratory gas flow, that is mean expiratory gas flow per unit lung volume, are calculated from the application of the model to the expiratory phase only only of a single breath activity-time curve which is generated from the multiple breath activity-time curve using post-acquisition gating. This method overcomes the problem of non-uniform inspiratory concentration of tracer gas experienced in previously reported techniques of analysing inhalation data obtained using poorly soluble radioactive gases. The model is shown, in simulation studies, to be an adequate description of the behaviour of radioactive gas in the lung and the analysis technique is shown, in clinical studies, to be both reproducible and sensitive to disease state. (orig.)

Cathodic Delamination Accelerated Life Test Method

National Research Council Canada - National Science Library

Ramotowski, Thomas S

2007-01-01

A method for conducting an accelerated life test of a polymer coated metallic sample includes placing the sample below the water surface in a test tank containing water and an oxygen containing gas...

Northwest Asia - gas market outlook: LNG vs. pipeline gas

International Nuclear Information System (INIS)

Keun Wook Paik

1996-01-01

The share of natural gas in Northeast Asia's energy mix is quite low despite that the region currently dominates the world LNG trade. In the long term, the region's rapid expansion of gas demand in the coming decades looks very likely, but the LNG dominance in the region's gas market will collapse in parallel with the introduction of a long distance pipeline gas. The most likely timing of pipeline gas introduction in Northeast Asian gas market seems to be during the second half of the next decade. (Author)

The last large pelletron accelerator of the Herb era

International Nuclear Information System (INIS)

Chopra, S.; Narayanan, M. M.; Joshi, R.; Gargari, S.; Kanjilal, D.; Datta, S. K.; Mehta, G. K.

1999-01-01

Prof. Ray Herb pioneered the concept and design of the tandem Pelletron accelerator in the late sixties at NEC. The 15UD Pelletron at Nuclear Science Centre (NSC), upgraded for 16MV operation using compressed geometry accelerating tubes is the last such large Pelletron. It has unique features like offset and matching quadrupoles after the stripper for charge state selection inside the high voltage terminal and consequently the option of further stripping the ion species of the selected charge states at high energy dead section, and elaborate pulsing system in the pre-acceleration region consisting of a beam chopper, a travelling wave deflector, a light ion buncher (1-80 amu) and a heavy ion buncher (>80 amu). NSC was established as a heavy ion accelerator based inter university centre in 1985. It became operational in July 1991 to cater to the research requirements of a large user community which at present includes about fifty universities, twenty-eight colleges and a dozen other academic institutes and research laboratories. The number of users in Materials and allied sciences is about 500. Various important modifications have been made to improve the performance of the accelerator in the last seven years. These include replacement of the corona voltage grading system by a resistor based one, a pick-up loop to monitor charging system performance, conversion from basic double unit structure to singlet, installation of a spiral cavity based phase detector system with post-accelerator stripper after the analyzing magnet, and a high efficiency multi harmonic buncher. Installation of a turbo pump based stripper gas recirculation system in the terminal is also planned. A brief description of utilization of the machine will be given

Formation and acceleration of precompressed compact tori in RACE

International Nuclear Information System (INIS)

Molvik, A.W.; Eddleman, J.L.; Hammer, J.H.; Hartman, C.W.; McLean, H.S.

1990-01-01

Many applications of the compact torus accelerator, CTA, concept (such as a driver for inertial fusion, or magnetically insulated inertial fusion) require maximizing the power density by compressing the compact torus, CT. The ring accelerator experiment, RACE, has compressed CT's by a factor of 2 in radius before acceleration, after being reconfigured with a precompressor cone followed by a short, 80 cm long, coaxial accelerator. The authors show the gas valves and gun, precompressor, and the beginning of the accelerator. The inner acceleration electrode begins at the precompressor cone after passing through the inner gun electrode. The authors discuss the experimental results of slow formation, compression, and acceleration in this new geometry

Reliability of high power electron accelerators for radiation processing

Energy Technology Data Exchange (ETDEWEB)

Zimek, Z. [Department of Radiation Chemistry and Technology, Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

2011-07-01

Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

Reliability of high power electron accelerators for radiation processing

International Nuclear Information System (INIS)

Zimek, Z.

2011-01-01

Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

Radio-isotope production using laser Wakefield accelerators

International Nuclear Information System (INIS)

Leemans, W.P.; Rodgers, D.; Catravas, P.E.; Geddes, C.G.R.; Fubiani, G.; Toth, C.; Esarey, E.; Shadwick, B.A.; Donahue, R.; Smith, A.; Reitsma, A.

2001-01-01

A 10 Hz, 10 TW solid state laser system has been used to produce electron beams suitable for radio-isotope production. The laser beam was focused using a 30 cm focal length f/6 off-axis parabola on a gas plume produced by a high pressure pulsed gas jet. Electrons were trapped and accelerated by high gradient wakefields excited in the ionized gas through the self-modulated laser wakefield instability. The electron beam was measured to contain excesses of 5 nC/bunch. A composite Pb/Cu target was used to convert the electron beam into gamma rays which subsequently produced radio-isotopes through (gamma, n) reactions. Isotope identification through gamma-ray spectroscopy and half-life time measurements demonstrated that Cu 61 was produced which indicates that 20-25 MeV gamma rays were produced, and hence electrons with energies greater than 25-30 MeV. The production of high energy electrons was independently confirmed using a bending magnet spectrometer. The measured spectra had an exponential distribution with a 3 MeV width. The amount of activation was on the order of 2.5 uCi after 3 hours of operation at 1 Hz. Future experiments will aim at increasing this yield by post-accelerating the electron beam using a channel guided laser wakefield accelerator

Architecture of petawatt-class z-pinch accelerators

Directory of Open Access Journals (Sweden)

W. A. Stygar

2007-03-01

Full Text Available We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (∼1   μs Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses (≪1   μs required to drive z pinches. The other is powered by linear transformer drivers (LTDs, which are less mature but produce much shorter pulses than conventional Marxes. Consequently, an LTD-driven accelerator promises to be (at a given pinch current and implosion time more efficient and reliable. The Marx-driven accelerator produces a peak electrical power of 500 TW and includes the following components: (i 300 Marx generators that comprise a total of 1.8×10^{4} capacitors, store 98 MJ, and erect to 5 MV; (ii 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii 600 5-MV laser-triggered gas switches; (iv three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi six magnetically insulated vacuum transmission lines (MITLs; and (vii a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210

Utilization of low-energy electron accelerators in Korea

International Nuclear Information System (INIS)

Lee, Byung Cheol

2003-01-01

There are more than 20 electron accelerators in Korea. Most of those are installed in factories for heat-resistant cables, heat-shrinkable cables, radial tires, foams, tube/ films, curing, etc. Four low-energy electron accelerators are in operation for research purposes such as polymer modification, purification of flue gas, waste water treatment, modification of semiconductor characteristics, etc. (author)

Utilization of low-energy electron accelerators in Korea

Energy Technology Data Exchange (ETDEWEB)

Lee, Byung Cheol [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2003-02-01

There are more than 20 electron accelerators in Korea. Most of those are installed in factories for heat-resistant cables, heat-shrinkable cables, radial tires, foams, tube/ films, curing, etc. Four low-energy electron accelerators are in operation for research purposes such as polymer modification, purification of flue gas, waste water treatment, modification of semiconductor characteristics, etc. (author)

Regional greenhouse gas emissions from cultivation of winter wheat and winter rapeseed for biofuels in Denmark

DEFF Research Database (Denmark)

Elsgaard, Lars; Olesen, Jørgen E; Hermansen, John Erik

2013-01-01

Biofuels from bioenergy crops may substitute a significant part of fossil fuels in the transport sector where, e.g., the European Union has set a target of using 10% renewable energy by 2020. Savings of greenhouse gas emissions by biofuels vary according to cropping systems and are influenced...... by such regional factors as soil conditions, climate and input of agrochemicals. Here we analysed at a regional scale the greenhouse gas (GHG) emissions associated with cultivation of winter wheat for bioethanol and winter rapeseed for rapeseed methyl ester (RME) under Danish conditions. Emitted CO2 equivalents...

Estimating household fuel oil/kerosine, natural gas, and LPG prices by census region

International Nuclear Information System (INIS)

Poyer, D.A.; Teotia, A.P.S.

1994-08-01

The purpose of this research is to estimate individual fuel prices within the residential sector. The data from four US Department of Energy, Energy Information Administration, residential energy consumption surveys were used to estimate the models. For a number of important fuel types - fuel oil, natural gas, and liquefied petroleum gas - the estimation presents a problem because these fuels are not used by all households. Estimates obtained by using only data in which observed fuel prices are present would be biased. A correction for this self-selection bias is needed for estimating prices of these fuels. A literature search identified no past studies on application of the selectivity model for estimating prices of residential fuel oil/kerosine, natural gas, and liquefied petroleum gas. This report describes selectivity models that utilize the Dubin/McFadden correction method for estimating prices of residential fuel oil/kerosine, natural gas, and liquefied petroleum gas in the Northeast, Midwest, South, and West census regions. Statistically significant explanatory variables are identified and discussed in each of the models. This new application of the selectivity model should be of interest to energy policy makers, researchers, and academicians

Analysis of the natural gas market in Fortaleza metropolitan region (Brazil); Analise do mercado de gas natural na regiao metropolitana de Fortaleza

Energy Technology Data Exchange (ETDEWEB)

Barroso, Carlos Andre M.; Rabelo, Clarice A.C.; Santana, Lana L.P.; Sucupira, Marcos L.L. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil)

2004-07-01

Natural gas has become one of the most important energy sources, as we can observe in most countries' energy sector, where its presence is very significant. In Brazil, natural gas corresponds to 7,5% of all energy Also available, and the government has plans to increase this number to 12% until 2010. However, in order to reach this goal, it is important to understand how market works, evaluating all the aspects that have some influence on it. This paper goal is to analyze the natural gas market in Fortaleza metropolitan region, emphasizing the industrial sector, the biggest consumer in Ceara State. The main aspects are characterized here, like professionals qualification in the area, service quality, from equipment and maintenance suppliers until gas distributors, legal aspects, and other factors that are also relevant to a possible future expansion of different natural gas market segments (industry, residence, commerce and transport). (author)

A Method to Simulate Linear Stability of Impulsively Accelerated Density Interfaces in Ideal-MHD and Gas Dynamics

International Nuclear Information System (INIS)

Samtaney, Ravi

2009-01-01

We present a numerical method to solve the linear stability of impulsively accelerated density interfaces in two dimensions such as those arising in the Richtmyer-Meshkov instability. The method uses an Eulerian approach, and is based on an unwind method to compute the temporally evolving base state and a flux vector splitting method for the perturbations. The method is applicable to either gas dynamics or magnetohydrodynamics. Numerical examples are presented for cases in which a hydrodynamic shock interacts with a single or double density interface, and a doubly shocked single density interface. Convergence tests show that the method is spatially second order accurate for smooth flows, and between first and second order accurate for flows with shocks

Strategy of steady economic development for petroleum and gas production enterprises in Kyzylorda region

International Nuclear Information System (INIS)

Dosmanbetov, B.S.; Kim, I.L.

1997-01-01

Main purpose of economic development strategy of Kyzylorda region is fastening of achieved results in area of micro-economic stabilization and structural and institutional transformation, cessation of production recession, rising of economy and growth of people's living standard. Growth of physical volumes of production and further decrease of annual rates of inflation is anticipated. It is noted, that during last years significant change in structure of industry branches have been happened. Specific gravity of branches related with raw petroleum and gas mining and processing became dominating one. Petroleum and gas industry development growth rate is caused by discovery of Kumkol deposit in 1984. Extracted supply is estimating in 90 million tones. The deposit has enormous importance for economy of Kyzylorda region

Cosmic-ray shock acceleration in oblique MHD shocks

Science.gov (United States)

Webb, G. M.; Drury, L. OC.; Volk, H. J.

1986-01-01

A one-dimensional, steady-state hydrodynamical model of cosmic-ray acceleration at oblique MHD shocks is presented. Upstream of the shock the incoming thermal plasma is subject to the adverse pressure gradient of the accelerated particles, the J x B force, as well as the thermal gas pressure gradient. The efficiency of the acceleration of cosmic-rays at the shock as a function of the upstream magnetic field obliquity and upstream plasma beta is investigated. Astrophysical applications of the results are briefly discussed.

MASSIVE CLUSTERS IN THE INNER REGIONS OF NGC 1365: CLUSTER FORMATION AND GAS DYNAMICS IN GALACTIC BARS

International Nuclear Information System (INIS)

Elmegreen, Bruce G.; Galliano, Emmanuel; Alloin, Danielle

2009-01-01

Cluster formation and gas dynamics in the central regions of barred galaxies are not well understood. This paper reviews the environment of three 10 7 M sun clusters near the inner Lindblad resonance (ILR) of the barred spiral NGC 1365. The morphology, mass, and flow of H I and CO gas in the spiral and barred regions are examined for evidence of the location and mechanism of cluster formation. The accretion rate is compared with the star formation rate to infer the lifetime of the starburst. The gas appears to move from inside corotation in the spiral region to looping filaments in the interbar region at a rate of ∼6 M sun yr -1 before impacting the bar dustlane somewhere along its length. The gas in this dustlane moves inward, growing in flux as a result of the accretion to ∼40 M sun yr -1 near the ILR. This inner rate exceeds the current nuclear star formation rate by a factor of 4, suggesting continued buildup of nuclear mass for another ∼0.5 Gyr. The bar may be only 1-2 Gyr old. Extrapolating the bar flow back in time, we infer that the clusters formed in the bar dustlane outside the central dust ring at a position where an interbar filament currently impacts the lane. The ram pressure from this impact is comparable to the pressure in the bar dustlane, and both are comparable to the pressure in the massive clusters. Impact triggering is suggested. The isothermal assumption in numerical simulations seems inappropriate for the rarefaction parts of spiral and bar gas flows. The clusters have enough lower-mass counterparts to suggest they are part of a normal power-law mass distribution. Gas trapping in the most massive clusters could explain their [Ne II] emission, which is not evident from the lower-mass clusters nearby.

On the structure of acceleration in turbulence

DEFF Research Database (Denmark)

Liberzon, A.; Lüthi, B.; Holzner, M.

2012-01-01

Acceleration and spatial velocity gradients are obtained simultaneously in an isotropic turbulent flow via three dimensional particle tracking velocimetry. We observe two distinct populations of intense acceleration events: one in flow regions of strong strain and another in regions of strong...... vorticity. Geometrical alignments with respect to vorticity vector and to the strain eigenvectors, curvature of Lagrangian trajectories and of streamlines for total acceleration, and for its convective part, , are studied in detail. We discriminate the alignment features of total and convective acceleration...... statistics, which are genuine features of turbulent nature from those of kinematic nature. We find pronounced alignment of acceleration with vorticity. Similarly, and especially are predominantly aligned at 45°with the most stretching and compressing eigenvectors of the rate of the strain tensor...

Investigation of pellet acceleration by an arc heated gas gun. An interim report of the investigations carried out to 31 August 1985

International Nuclear Information System (INIS)

Andersen, S.A.; Bundgaard, J.; Jensen, V.O.; Nordskov, A.; Sass, B.; Soerensen, H.; Weisberg, K.V.

1985-12-01

Deep penetration of pellets into the JET plasma may prove to be a useful tool for density and profile control. In JET deep penetration will require pellet velocities and sizes above those obtained so far. An experimental setup designed for a study of acceleration of 3 mm diameter pellets by an arc heated gas gun is described. The aim of the work is to obtain pellet velocities well above 2 km/s. To obtain this aim will require a much more powerful power unit than the one that was available for the present work. Only a few results, obtained mostly during testing of the various parts of the setup, are presented. Although the obtained velocities are low (∝1500 m/s) the results are encouraging because they demonstrate that pellets can stand a high acceleration pressure without disintegrating. With a suitable power supply which can maintain this high acceleration pressure as the pellet moves all the way through the barrel, velocities above 2 km/s would certainly be expected. (orig.)

Discharges in the inlet region of a noble gas MHD generator

International Nuclear Information System (INIS)

Borghi, C.A.

1982-01-01

In this work the onset of the development of the non-equilibrium conductivity in the entrance region of a noble gas MHD generator is investigated both theoretically and experimentally. At low electron densities the discharge seems to be affected by a non-Maxwellian electron distribution. In Chapter II a self-consistent model of a stationary discharge in an Ar-Cs mixture at atmospheric pressure, is set up. It includes the possibility of deviations from a Maxwellian electron energy distribution. The model allows to calculate at what discharge parameters deviations from the Maxwellian electron distribution will become important. In Chapter III the relaxation of the plasma to a new equilibrium situation following a sudden change in the electron thermal energy is calculated by a model which can take radiation and a non-Maxwellian distribution into account. In Chapter IV an Ar-Cs discharge experiment is described with plasma parameters similar to those present in the entrance region of the generator. The ionization relaxation process in a noble gas MHD generator is experimentally studied and described in Chapter V. In this chapter the relaxation ionization region with and without pre-ionization is investigated. Current voltage characteristics are obtained by varying the applied voltage or the external load. The results are confronted with the theoretical results of the non-Maxwellian model developed in Chapter II. Conclusions of this work are drawn in Chapter VI. (Auth.)

Urban form and greenhouse gas emissions in Finland

International Nuclear Information System (INIS)

Harmaajaervi, Irmeli

2003-01-01

Finland's regional form is becoming more concentrated, while urban sprawl is causing growth centres to become fragmented. The effects caused by these changes on greenhouse gas emissions were studied up to the year 2010, when, in accordance with the Kyoto protocol, Finland's greenhouse gas emissions should be reduced to the 1990 level. The urban form affects especially transportation inside regions, the potential to utilise district heating and the need for infrastructure. By preventing urban sprawl and by encouraging teleworking and some lifestyle changes, it would be possible to reduce annual transportation emissions by the year 2010 by 1.1 million tonnes CO 2 eq., i.e. 27%, the emissions from residential and service buildings by 1.1 million tonnes CO 2 eq., i.e. 5%, and the emissions from municipal infrastructure by 0.1 million tonnes CO 2 eq., i.e. 6%. Altogether, it is possible to reduce the greenhouse gas emissions by 2.3 million tonnes, which amounts to 15% of Finland's target for emissions reductions in 2010. If the target-oriented scenario is realised, the subsequent decrease of emissions would accelerate. To stop urban sprawl, measures are required in planning, land use and housing policy as well as in transportation and tax policies. Additionally, more needs to be done in regard to co-operation, interaction and information dissemination. This paper introduces a report which estimates, for the first time, the effects caused by changes in the regional and urban forms on the levels of greenhouse gas emissions in Finland

Acceleration of small, light projectiles (including hydrogen isotopes) to high speeds using a two-stage light gas gun

International Nuclear Information System (INIS)

Combs, S.K.; Foust, C.R.; Gouge, M.J.; Milora, S.L.

1989-01-01

Small, light projectiles have been accelerated to high speeds using a two-stage light gas gun at Oak Ridge National Laboratory. With 35-mg plastic projectiles (4 mm in diameter), speeds of up to 4.5 km/s have been recorded. The ''pipe gun'' technique for freezing hydrogen isotopes in situ in the gun barrel has been used to accelerate deuterium pellets (nominal diameter of 4 mm) to velocities of up to 2.85 km/s. The primary application of this technology is for plasma fueling of fusion devices via pellet injection of hydrogen isotopes. Conventional pellet injectors are limited to pellet speeds in the range 1-2 km/s. Higher velocities are desirable for plasma fueling applications, and the two-stage pneumatic technique offers performance in a higher velocity regime. However, experimental results indicate that the use of sabots to encase the cryogenic pellets and protect them for the high peak pressures will be required to reliably attain intact pellets at speeds of ∼3 km/s or greater. In some limited tests, lithium hydride pellets were accelerated to speeds of up to 4.2 km/s. Also, repetitive operation of the two-stage gun (four plastic pellets fired at ∼0.5 Hz) was demonstrated for the first time in preliminary tests. The equipment and operation are described, and experimental results and some comparisons with a theoretical model are presented. 17 refs., 6 figs., 2 tabs

A cocoon of freshly accelerated cosmic rays detected by Fermi in the Cygnus Superbubble

International Nuclear Information System (INIS)

Ackermann, M.; Ajello, A.; Allafort, A.; Berenji, B.; Blandford, R.D.; Bloom, E.D.; Borgland, A.W.; Bottacini, E.; Buehler, R.; Cameron, R.A.; Chiang, J.; Claus, R.; Do Couto e Silva, E.; Drell, P.S.; Focke, W.B.; Glanzman, T.; Godfrey, G.; Hayashida, M.; Johnson, A.S.; Kamae, T.; Kerr, M.; Lande, J.; Michelson, P.F.; Mitthumsiri, W.; Monzani, M.E.; Moskalenko, I.V.; Murgia, S.; Nolan, P.L.; Okumura, A.; Orlando, E.; Paneque, D.; Prokhorov, D.; Tanaka, T.; Thayer, J.G.; Thayer, J.B.; Tramacere, A.; Uchiyama, Y.; Vandenbroucke, J.; Vianello, G.; Waite, A.P.; Wang, P.; Baldini, L.; Bellazzini, R.; Kuss, M.; Latronico, L.; Pesce-Rollins, M.; Razzano, M.; Sgro, C.; Ballet, J.; Casandjian, J.M.; Grenier, I.A.; Naumann-Godo, M.; Pierbattista, M.; Tibaldo, L.

2011-01-01

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shock waves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-giga-electron-volt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population. (authors)

Complex calculation and improvement of beam shaping and accelerating system of the ''Sokol'' small-size electrostatic accelerator

International Nuclear Information System (INIS)

Simonenko, A.V.; Pistryak, V.M.; Zats, A.V.; Levchenko, Yu.Z.; Kuz'menko, V.V.

1987-01-01

Features of charged particle accelerated beam shaping in the electrostatic part of the ''Sokol'' small-size accelerator are considered in complex taking into account the electrode real geometry. Effect of the extracting, accelerating electorde potential and accelerator total voltage on beam behaviour is investigated. A modified variation of the beam shaping system, allowing to decrease 2 times the required interval of accelerating electrode potential adjustment and to decrease the beam size in the starting acceleration region, is presented. It permits to simplify the construction and to improve accelerator operation. Comparison of experimental and calculational data on the beam in the improved accelerator variation is carried out. Effect of peripheral parts of accelerating tube electrodes on the beam is investigated

Numerical Simulation on the Partition of Gas-Rich Region in Overlying Strata

Directory of Open Access Journals (Sweden)

G. Wang

2014-03-01

Full Text Available In the background of Kongzhuang coal mine 7433 working face, theoretical analysis and numerical simulation are adopted. The partition method of gas-rich region in overlying strata based on the key stratum is proposed. Overlying stratas are divided into low concentration and easy for gas drainage area, high concentration and easy for drainage area, primary stress zone according to the control action of key stratum in overlying stratas. The numerical simulation shows that fissure development range is gradually scaling up ,and the development range of bed separated fissures and vertical fissures extend to the second inferior key stratum step-by-step with the working face moving forward The fissure development range stabilizes as the roof periodic motion and moves forward with the working face moving forward. Compared to traditional empirical formula calculation result, the top boundary of high concentration and easy for drainage area according to this method is higher than the calculated limit of water flowing fractured zone. The design of gas drainage can be more accurately guided. Better gas drainage effect is obtained by the design of gas drainage in 7433 working face which is based on this method and the numerical simulation result. The effectiveness and rationality of this method are verified.

ENTROPY AT THE OUTSKIRTS OF GALAXY CLUSTERS AS IMPLICATIONS FOR COSMOLOGICAL COSMIC-RAY ACCELERATION

International Nuclear Information System (INIS)

Fujita, Yutaka; Ohira, Yutaka; Yamazaki, Ryo

2013-01-01

Recently, gas entropy at the outskirts of galaxy clusters has attracted much attention. We propose that the entropy profiles could be used to study cosmic-ray (CR) acceleration around the clusters. If the CRs are effectively accelerated at the formation of clusters, the kinetic energy of infalling gas is consumed by the acceleration and the gas entropy should decrease. As a result, the entropy profiles become flat at the outskirts. If the acceleration is not efficient, the entropy should continue to increase outward. By comparing model predictions with X-ray observations with Suzaku, which show flat entropy profiles, we find that the CRs have carried ∼< 7% of the kinetic energy of the gas away from the clusters. Moreover, the CR pressure at the outskirts can be ∼< 40% of the total pressure. On the other hand, if the entropy profiles are not flat at the outskirts, as indicated by combined Plank and ROSAT observations, the carried energy and the CR pressure should be much smaller than the above estimations.

Puffing topography and nicotine intake of electronic cigarette users.

Directory of Open Access Journals (Sweden)

Rachel Z Behar

Full Text Available Prior electronic cigarette (EC topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake.This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake.Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10-15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data.Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff, volume/puff (51 ml/puff, total puff volume (1,579 ml, EC fluid consumption (79.6 mg, flow rate (20 ml/s, and peak flow rate (27 ml/s were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers.EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products.

Puffing Topography and Nicotine Intake of Electronic Cigarette Users

Science.gov (United States)

Behar, Rachel Z.; Hua, My; Talbot, Prue

2015-01-01

Background Prior electronic cigarette (EC) topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake. Objectives This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake. Methods Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10–15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data. Results Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff), volume/puff (51ml/puff), total puff volume (1,579 ml), EC fluid consumption (79.6 mg), flow rate (20 ml/s), and peak flow rate (27 ml/s) were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers. Conclusions EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products

100 MeV laser accelerator demonstration and 1 GeV baseline design development. 1992 Annual report

International Nuclear Information System (INIS)

1992-01-01

The acceleration of relativistic electrons using the inverse Cerenkov effect was first demonstrated at Stanford University in 1981. Later, Fontana and Pantell developed an improved configuration for the inverse Cerenkov acceleration (ICA) process. A radially polarized laser beam is focused by an axicon onto the e-beam traveling through a gas-filled interaction region. The light intersects the e-beam at the Cerenkov angle θ c , where θ c = cos -1 (1/nβ), n is the index of refraction of the gas, and β is the ratio of the electron velocity to the speed of light. The goal of the present program is to demonstrate improved laser acceleration using the Fontana and Pantell configuration. The experiments will be performed on the Accelerator Test Facility (ATF) located at Brookhaven National Laboratory (BNL). This facility features a 50 MeV linac fed by a Nd:YAG (4ω) laser-driven photocathode e-gun. It will be upgraded to 65 MeV in the near future. The ATF also has a high peak power CO 2 laser, which was developed for laser acceleration studies. The present ICA experiment was divided into two phases. Phase 1 was to examine certain experimental issues in preparation for Phase 2. Phase 1 was successfully completed in the spring of 1992. Phase 2 is to perform the actual laser acceleration experiments on the ATF e-beam. The authors are currently waiting for the availability of the e-beam so that they can begin the Phase 2 experiments. In this section, the theory and experimental hardware for the present program are described. The results of the Phase 1 experiments are presented, and an update on the Phase 2 experiment is given

Compact electron accelerator for pumping gas lasers

International Nuclear Information System (INIS)

Duncan, C.V.; Bradley, L.P.

1976-01-01

A description is given of the design and application of a simple e-beam generator for the repetitive pulse pumping of gas lasers. The circuit uses a low inductance Marx and series tuned pulse forming elements

Review of Sector and Regional Trends in U.S. Electricity Markets. Focus on Natural Gas. Natural Gas and the Evolving U.S. Power Sector Monograph Series. Number 1 of 3

Energy Technology Data Exchange (ETDEWEB)

Logan, Jeffrey; Medlock III, Kenneth B.; Boyd, William C.

2015-10-15

This study explores dynamics related to natural gas use at the national, sectoral, and regional levels, with an emphasis on the power sector. It relies on a data set from SNL Financial to analyze recent trends in the U.S. power sector at the regional level. The research aims to provide decision and policy makers with objective and credible information, data, and analysis that informs their discussions of a rapidly changing energy system landscape. This study also summarizes regional changes in natural gas demand within the power sector. The transition from coal to natural gas is occurring rapidly along the entire eastern portion of the country, but is relatively stagnant in the central and western regions. This uneven shift is occurring due to differences in fuel price costs, renewable energy targets, infrastructure constraints, historical approach to regulation, and other factors across states.

The Auroral Field-aligned Acceleration - Cluster Results

Science.gov (United States)

Vaivads, A.; Cluster Auroral Team

The four Cluster satellites cross the auroral field lines at altitudes well above most of acceleration region. Thus, the orbit is appropriate for studies of the generator side of this region. We consider the energy transport towards the acceleration region and different mechanisms for generating the potential drop. Using data from Cluster we can also for the first time study the dynamics of the generator on a minute scale. We present data from a few auroral field crossings where Cluster are in conjunction with DMSP satellites. We use electric and magnetic field data to estimate electrostatic po- tential along the satellite orbit, Poynting flux as well as the presence of plasma waves. These we can compare with data from particle and wave instruments on Cluster and on low latitude satellites to try to make a consistent picture of the acceleration region formation in these cases. Preliminary results show close agreement both between in- tegrated potential values at Cluster and electron peak energies at DMSP as well as close agreement between the integrated Poynting flux values at Cluster and the elec- tron energy flux at DMSP. At the end we draw a parallels between auroral electron acceleration and electron acceleration at the magnetopause.

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

International Nuclear Information System (INIS)

Combs, S.K.; Milora, S.L.; Foust, C.R.; Gouge, M.J.; Fehling, D.T.; Sparks, D.O.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/ 3 for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of ∼3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab

Accelerated Educational Change; The Annual Western Regional Conference on Testing Problems (15th, San Francisco, California, May 6, 1966).

Science.gov (United States)

Educational Testing Service, Princeton, NJ.

The 1966 meeting of the Western Regional Conference on Testing Problems dealt with accelerated educational change. The following speeches were presented: (1) "Access to Higher Education: Implications for Future Planning" by Richard Pearson; (2) "The Differentiated Youth: A Challenge to Traditional Institutions" by Joseph D. Lohman; (3) "Teaching…

Regional impacts of oil and gas development on ozone formation in the western United States.

Science.gov (United States)

Rodriguez, Marco A; Barna, Michael G; Moore, Tom

2009-09-01

The Intermountain West is currently experiencing increased growth in oil and gas production, which has the potential to affect the visibility and air quality of various Class I areas in the region. The following work presents an analysis of these impacts using the Comprehensive Air Quality Model with extensions (CAMx). CAMx is a state-of-the-science, "one-atmosphere" Eulerian photochemical dispersion model that has been widely used in the assessment of gaseous and particulate air pollution (ozone, fine [PM2.5], and coarse [PM10] particulate matter). Meteorology and emissions inventories developed by the Western Regional Air Partnership Regional Modeling Center for regional haze analysis and planning are used to establish an ozone baseline simulation for the year 2002. The predicted range of values for ozone in the national parks and other Class I areas in the western United States is then evaluated with available observations from the Clean Air Status and Trends Network (CASTNET). This evaluation demonstrates the model's suitability for subsequent planning, sensitivity, and emissions control strategy modeling. Once the ozone baseline simulation has been established, an analysis of the model results is performed to investigate the regional impacts of oil and gas development on the ozone concentrations that affect the air quality of Class I areas. Results indicate that the maximum 8-hr ozone enhancement from oil and gas (9.6 parts per billion [ppb]) could affect southwestern Colorado and northwestern New Mexico. Class I areas in this region that are likely to be impacted by increased ozone include Mesa Verde National Park and Weminuche Wilderness Area in Colorado and San Pedro Parks Wilderness Area, Bandelier Wilderness Area, Pecos Wilderness Area, and Wheeler Peak Wilderness Area in New Mexico.

High-energy inverse free-electron laser accelerator

International Nuclear Information System (INIS)

Courant, E.D.; Pellegrini, C.; Zakowicz, W.

1985-01-01

We study the inverse free electron laser (IFEL) accelerator and show that it can accelerate electrons to the few hundred GeV region with average acceleration rates of the order of 200 meV/m. Several possible accelerating structures are analyzed, and the effect of synchrotron radiation losses is studied. The longitudinal phase stability of accelerated particles is also analyzed. A Hamiltonian description, which takes into account the dissipative features of the IFEL accelerator, is introduced to study perturbations from the resonant acceleration. Adiabatic invariants are obtained and used to estimate the change of the electron phase space density during the acceleration process

ORNL pellet acceleration program

International Nuclear Information System (INIS)

Foster, C.A.; Milora, S.L.

1978-01-01

The Oak Ridge National Laboratory (ORNL) pellet fueling program is centered around developing equipment to accelerate large pellets of solidified hydrogen to high speeds. This equipment will be used to experimentally determine pellet-plasma interaction physics on contemporary tokamaks. The pellet experiments performed on the Oak Ridge Tokamak (ORMAK) indicated that much larger, faster pellets would be advantageous. In order to produce and accelerate pellets of the order of 1 to 6 mm in diameter, two apparatuses have been designed and are being constructed. The first will make H 2 pellets by extruding a filament of hydrogen and mechanically chopping it into pellets. The pellets formed will be mechanically accelerated with a high speed arbor to a speed of 950 m/sec. This technique may be extended to speeds up to 5000 m/sec, which makes it a prime candidate for a reactor fueling device. In the second technique, a hydrogen pellet will be formed, loaded into a miniature rifle, and accelerated by means of high pressure hydrogen gas. This technique should be capable of speeds of the order of 1000 m/sec. While this technique does not offer the high performance of the mechanical accelerator, its relative simplicity makes it attractive for near-term experiments

36Chlorine accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator. RSP-12

International Nuclear Information System (INIS)

Surendran, P.; Shrivastava, A.; Gupta, A.K.; Nair, J.P.; Yadav, M.L.; Gore, J.A.; Sparrow, H.; Bhagwat, P.V.; Kailas, S.; Kale, R.M.; Hemalatha, M.

2007-01-01

Accelerator mass spectrometry (AMS) is an ultra sensitive means of counting individual atoms having sufficiently long half life and available in small amount. The 14 UD Pelletron Accelerator is an ideal machine to carry out AMS studies with heavy isotopes like 36 Cl and 129 I. Cosmogenic radio isotope 36 Cl is widely being detected using AMS as it has got applications in ground water research, radioactive waste management, atmospheric 36 Cl transport mechanism studies of Arctic Alpine ice core etc. As a part of the ongoing AMS programme at 14UD Pelletron Accelerator Facility, Mumbai, a segmented gas detector developed for identification of 36 Cl was tested for performance. Recently a beam chopper required for this measurement has been developed. 36 Cl measurements carried out to detect and measure the ratio of 36 Cl to 35 Cl in an irradiated sample and dated sample are reported in this paper

Source Population and Acceleration Location of Suprathermal Heavy Ions in Corotating Interaction Regions

Energy Technology Data Exchange (ETDEWEB)

Filwett, R. J.; Desai, M. I. [University of Texas at San Antonio, San Antonio, TX (United States); Dayeh, M. A.; Broiles, T. W. [Southwest Research Institute, San Antonio, TX (United States)

2017-03-20

We have analyzed the ∼20–320 keV nucleon{sup −1} suprathermal (ST) heavy ion abundances in 41 corotating interaction regions (CIRs) observed by the Wind spacecraft from 1995 January to 2008 December. Our results are: (1) the CIR Fe/CNO and NeS/CNO ratios vary with the sunspot number, with values being closer to average solar energetic particle event values during solar maxima and lower than nominal solar wind values during solar minima. The physical mechanism responsible for the depleted abundances during solar minimum remains an open question. (2) The Fe/CNO increases with energy in the 6 events that occurred during solar maximum, while no such trends are observed for the 35 events during solar minimum. (3) The Fe/CNO shows no correlation with the average solar wind speed. (4) The Fe/CNO is well correlated with the corresponding upstream ∼20–320 keV nucleon{sup −1} Fe/CNO and not with the solar wind Fe/O measured by ACE in 31 events. Using the correlations between the upstream ∼20–40 keV nucleon{sup −1} Fe/CNO and the ∼20–320 keV nucleon{sup −1} Fe/CNO in CIRs, we estimate that, on average, the ST particles traveled ∼2 au along the nominal Parker spiral field line, which corresponds to upper limits for the radial distance of the source or acceleration location of ∼1 au beyond Earth orbit. Our results are consistent with those obtained from recent surveys, and confirm that CIR ST heavy ions are accelerated more locally, and are at odds with the traditional viewpoint that CIR ions seen at 1 au are bulk solar wind ions accelerated between 3 and 5 au.

Ionization and pulse lethargy effects in inverse Cherenkov accelerators

International Nuclear Information System (INIS)

Sprangle, P.; Hubbard, R.F.; Hafizi, B.

1997-01-01

Ionization processes limit the accelerating gradient and place an upper limit on the pulse duration of the electromagnetic driver in the inverse Cherenkov accelerator (ICA). Group velocity slippage, i.e., pulse lethargy, on the other hand, imposes a lower limit on the pulse duration. These limits are obtained for two ICA configurations in which the electromagnetic driver (e.g., laser or millimeter wave source) is propagated in a waveguide that is (i) lined with a dielectric material or (ii) filled with a neutral gas. In either configuration the electromagnetic driving field is guided and has an axial electric field with phase velocity equal to the speed of light in vacuum, c. The intensity of the driver in the ICA, and therefore the acceleration gradient, is limited by tunneling and collisional ionization effects. Partial ionization of the dielectric liner or gas can lead to significant modification of the dispersive properties of the waveguide, altering the phase velocity of the accelerating field and causing particle slippage, thus disrupting the acceleration process. An additional limitation on the pulse duration is imposed since the group velocity of the driving pulse is less than c and the pulse slips behind the accelerated electrons. Hence for sufficiently short pulses the electrons outrun the pulse, terminating the acceleration. Limitations on the driver pulse duration and accelerating gradient, due to ionization and pulse lethargy, are estimated for the two ICA configurations. Maximum accelerating gradients and pulse durations are presented for a 10 μm, 1 mm, and 1 cm wavelength electromagnetic driver. The combination of ionization and pulse lethargy effects impose severe limitations on the maximum energy gain in inverse Cherenkov accelerators. copyright 1997 The American Physical Society

Studies of hydrogen pellet acceleration with fuseless electromagnetic railgun

International Nuclear Information System (INIS)

Kim, K.

1986-01-01

A fuseless circular-bore electromagnetic railgun specifically designed for injection of high-velocity hydrogen pellets was constructed and tested. Hydrogen pellets were first accelerated to medium velocities (∼ 500 m/s) using a gas gun and then injected into the railgun. Once a pellet entered the railgun, a plasma arc was initiated by electrically breaking down the propellant gas which followed the pellet from the gas gun into the railgun. Utilizing the propulsive force of this plasma arc armature, further acceleration of the hydrogen pellet was achieved. Using a 60 cm long railgun, proof-of-principle experiments were performed on hydrogen pellets, 1.6 mm, in diameter and 2.15 mm in length, producing velocities exceeding 1.5 km/s. Encouraged by this preliminary success, more extensive studies are in progress to further improve the performance and capabilities of the current system

Implications of greenhouse gas emission mitigation scenarios for the main Asian regions

International Nuclear Information System (INIS)

Ruijven, Bas J. van; Vuuren, Detlef P. van; Vliet, Jasper van; Mendoza Beltran, Angelica; Deetman, Sebastiaan; Elzen, Michel G.J. den

2012-01-01

In order to limit global mean temperature increase, long-term greenhouse gas emissions need to be reduced. This paper discusses the implications of greenhouse gas emission reductions for major Asian regions (China, India, Indonesia, South-East Asia, Japan and Korea) based on results from the IMAGE modelling framework. Energy use in regions and economic sectors is affected differently by ambitious climate policies. We find that the potential for emission reduction varies widely between regions. With respect to technology choices in the power sector, we find major application of CO 2 storage in Indonesia and India, whereas Korea and India apply more solar and wind. Projections for Japan include a (debatable) large share of nuclear power. China and, India, and South-East Asia, show a diverse technology choice in the power sector. For the industry sector, we find that the recent rapid growth in China limits the potential for emission reduction in the next decades, assuming that recently built coal-based industry facilities are in use for the next decades. For the residential sector, the model results show that fewer households switch from traditional fuels to modern fuels in GHG mitigation scenarios. With respect to co-benefits, we find lower imports of fossil energy in mitigation scenarios and a clear reduction of air pollutant emissions. - Highlights: ► The potential for emission reduction varies widely between regions. ► Some regions have attractive CO 2 storage capacity; others have low-cost solar/wind potential. ► The recent rapid growth of Chinese industry may limit emission reduction potential for decades. ► Fewer households switch from traditional fuels to modern fuels in mitigation scenarios. ► Mitigation scenarios show less fossil energy import and reduction of air pollutant emission.

Engineering design of a Radiative Divertor for DIII-D

International Nuclear Information System (INIS)

Smith, J.P.; Allen, S.L.; Anderson, P.M.; Baxi, C.B.; Chin, E.; Fenstermacher, M.E.; Hill, D.N.; Hollerbach, M.A.; Hyatt, A.W.; Junge, R.; Mahdavi, M.A.; Porter, G.D.; Redler, K.; Reis, E.E.; Schaffer, M.J.; Sevier, D.L.; Stambaugh, R.D.

1995-01-01

A new divertor called the Radiative Divertor is presently being designed for the DIII-D tokamak. Input from tokamak experiments and modeling form the basis for the new design. The Radiative Divertor is intended to reduce the heat flux on the divertor plates by dispersing the power with radiation. Gas puffing experiments in the current open divertor have shown a reduction of the divertor heat flux with either deuterium or impurity puffing. However, either the plasma density (D 2 ) or the core Z eff (impurities) increases in these experiments. The radiative divertor uses a slot structure to isolate the divertor plasma region from the area surrounding the core plasma. Modeling has shown that the Radiative Divertor hardware will provide better baffling and particle control and thereby minimize the effect of the gas puffing in the divertor region on the plasma core. In addition, the Radiative Divertor structure will allow density control in plasma shapes with high triangularity (>0.8) required for advanced tokamak operation. The divertor structure allows for operation in either double or single-null plasma configurations. Four independently controlled divertor cryopumps will enable pumping at either the inboard (upper and lower) or the outboard (upper and lower) divertor plates. Biasing is an integral part of the design and is based on experience at the Tokamak de Varennes (TdeV) and DIII-D. Boron nitride tiles electrically insulate the inner and outer strike points and a low current electrode is used to apply a radial electric field to the scrape-off layer. TdeV has shown that biasing can provide particle and impurity control. The design is extremely flexible, and will allow physics studies of the effect of slot width and height. This is extremely important, as the amount of chamber volume needed for the divertor in future machines such as International Thermonuclear Experiment Reactor (ITER) and Tokamak Physics Experiment (TPX) must be determined. (orig./WL)

Highly efficient accelerator of dense matter using laser-induced cavity pressure acceleration

Czech Academy of Sciences Publication Activity Database

Badziak, J.; Jabloňski, S.; Pisarczyk, T.; Rączka, P.; Krouský, Eduard; Liska, R.; Kucharik, M.; Chodukowski, T.; Kalinowska, Z.; Parys, P.; Rosiński, M.; Borodziuk, S.; Ullschmied, Jiří

2012-01-01

Roč. 19, č. 5 (2012), s. 1-8 ISSN 1070-664X R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : plasma accelerators * plasma density * plasma inertial confinement * plasma light propagation * plasma pressure * plasma transport processes Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.376, year: 2012

Electron accelerators for environmental protection

International Nuclear Information System (INIS)

Zimek, Z.

1998-01-01

The primary objective of this publication is to provide information suitable for electron accelerators implementation in facilities applying radiation technology for environmental protection. It should be noticed that radiation processing has been successfully used in the fields of crosslinking polymer curing and medical products sterilization for more than 40 years. Practical application of radiation technology today extends on SO 2 and NO x removal from the flue gas (one of major power intensive radiation processing), destruction and removal of organic chemicals from water, decreasing bacteria content in the irradiated sludge and waste water. On the other hand the increased awareness of environmental pollution hazards and more stringent waste regulations in many countries may open stronger support for environmentally oriented technologies. This publication provides an evaluation of electron accelerators capabilities in respect of environmental applications where technological and economical criteria are now well defined. In order to determine the potential of electron accelerators, the literature data were examined as well visits and meetings with various accelerator manufacturers were performed by the author. Experience of the author in accelerator facilities construction and exploitation including those which were used for environmental protection are significant part of this publication. The principle of accelerator action was described in Chapter 1. Early development, accelerator classification and fields of accelerators application were included to this chapter as well. Details of accelerator construction was described in Chapter 2 to illustrate physical capability of accelerators to perform the function of ionizing radiation source. Electron beam extraction devices, under beam equipment, electron beam parameters and measuring methods were characterized in this chapter as well. Present studies of accelerator technology was described in Chapter 3, where

Method and apparatus for accelerating a solid mass

International Nuclear Information System (INIS)

Tidman, D.A.; Goldstein, Y.A.

1984-01-01

An axi-symmetrical projectile, having a mass ranging from fractions of a gram to kilograms, is accelerated to velocities in the range of 10 5 to 10 7 centimeters per second by a propelling force produced by a plasma resulting from electric discharge. The discharge is imploded against the projectile surface so lines of the magnetic fields are approximately azimuthal around the projectile axis. The projectile is tapered so it experiences a net, stable axial accelerating force along the accelerator axis by the combined action of the magnetic field producing radially directed momentum and pressure on the plasma, the interaction of the magnetic field and ions induced by the plasma on the surface, as well as material the plasma ablates from the surface. The plasma discharge is initiated either in low density background gas between anode and cathode of a discharge module, or along an insulator surface between the electrodes in low density background gas. Alternatively, in either of these situations the discharge can be initiated in a gas which is produced by ablation of the projectile surface. In an alternative situation, the projectile acts as a switch for triggering discharges. Eddy current heating of the projectile is minimized by shaping the discharge current pulse so the plasma has a relatively weak magnetic field when it arrives at the surface, or by making the projectile electrically non-conducting. To provide a long acceleration path, a series of modules is aligned. In one embodiment, the projectile position, as it advances between modules, is sensed and discharges are switched on sequentially in the modules