Secured Hash Based Burst Header Authentication Design for Optical Burst Switched Networks

Science.gov (United States)

Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

2017-12-01

The optical burst switching (OBS) is a promising technology that could meet the fast growing network demand. They are featured with the ability to meet the bandwidth requirement of applications that demand intensive bandwidth. OBS proves to be a satisfactory technology to tackle the huge bandwidth constraints, but suffers from security vulnerabilities. The objective of this proposed work is to design a faster and efficient burst header authentication algorithm for core nodes. There are two important key features in this work, viz., header encryption and authentication. Since the burst header is an important in optical burst switched network, it has to be encrypted; otherwise it is be prone to attack. The proposed MD5&RC4-4S based burst header authentication algorithm runs 20.75 ns faster than the conventional algorithms. The modification suggested in the proposed RC4-4S algorithm gives a better security and solves the correlation problems between the publicly known outputs during key generation phase. The modified MD5 recommended in this work provides 7.81 % better avalanche effect than the conventional algorithm. The device utilization result also shows the suitability of the proposed algorithm for header authentication in real time applications.

Detection and Repair of Ligament Cracks in a 109mm Thick Superheater Outlet Header

International Nuclear Information System (INIS)

Day, Peter

2006-01-01

Conventional thermal power station boilers are constructed of drums and a series of headers which are interconnected with many hundreds of tubes. Typically feed water enters the boiler at about 250 deg C at a pressure of around 250 bar with steam outlet temperatures of 540 deg C and a pressure of 170 bar. Superheater outlet headers may be subjected to quite arduous conditions during service. Not only are they exposed to high pressure stresses but also to high thermal stresses due to varying thermal gradients through the section thickness particularly at start up and during two shift operation. The area that is exposed to the greatest thermal gradients is the narrow ligament that exists between the tube hole penetrations in the header bore. In the mid the 1980's industry wide surveys found cracking in a large percentage (25-50%) of headers after 15 years of service. Detection and sizing of ligament cracking and estimates of the rate of growth are therefore a major consideration especially in plant that is two shifted. In order to manage the risk both remote visual and ultrasonic inspection are performed during each major unit overhaul. Conclusion: Ultrasonic techniques used for this inspection need to be carefully evaluated with respect to their effectiveness. Conventional pulse echo is capable of detection but using for example a technique such as AS2207 level 1 will not show the defect size. Time of flight diffraction has shown itself to be effective in accurately sizing ligament cracking. However the complex geometry of header ligaments appears to cause a narrowing of the beam with the effect that crack tip responses can be concentrated at the centre of the ligament. Therefore great care needs to be taken during data interrogation because errors in sizing can occur. Wherever possible both 'B' and 'D' scan data should be collected. It appears that the greatest accuracy is obtained with respect to defect growth from the B scan image. With respect to the welding a

A Study on Thermal Performance of a Novel All-Glass Evacuated Tube Solar Collector Manifold Header with an Inserted Tube

Directory of Open Access Journals (Sweden)

Jichun Yang

2015-01-01

Full Text Available A novel all-glass evacuated tube collector manifold header with an inserted tube is proposed in this paper which makes water in all-glass evacuated solar collector tube be forced circulated to improve the performance of solar collector. And a dynamic numerical model was presented for the novel all-glass evacuated tube collector manifold header water heater system. Also, a test rig was built for model validation and comparison with traditional all-glass evacuated tube collector. The experiment results show that the efficiency of solar water heater with a novel collector manifold header is higher than traditional all-glass evacuated tube collector by about 5% and the heat transfer model of water heater system is valid. Based on the model, the relationship between the average temperature of water tank and inserted tube diameter (water mass flow has been studied. The results show that the optimized diameter of inserted tube is 32 mm for the inner glass with the diameter of 47 mm and the water flow mass should be less than 1.6 Kg/s.

RObust header compression (ROHC) performance for multimedia transmission over 3G/4G wireless networks

DEFF Research Database (Denmark)

Fitzek, Frank; Rein, S.; Seeling, P.

2005-01-01

Robust Header Compression (ROHC) has recently been proposed to reduce the large protocol header overhead when transmitting voice and other continuous meadi over IP based control stacks in wireless networks. In this paper we evaluate the real-time transmission of GSM encoded voice and H. 26L encod...

Phishtest: Measuring the Impact of Email Headers on the Predictive Accuracy of Machine Learning Techniques

Science.gov (United States)

Tout, Hicham

2013-01-01

The majority of documented phishing attacks have been carried by email, yet few studies have measured the impact of email headers on the predictive accuracy of machine learning techniques in detecting email phishing attacks. Research has shown that the inclusion of a limited subset of email headers as features in training machine learning…

40 Gbit/s NRZ Packet-Length Insensitive Header Extraction for Optical Label Switching Networks

DEFF Research Database (Denmark)

Seoane, Jorge; Kehayas, E; Avramopoulos, H.

2006-01-01

A simple method for 40 Gbit/s NRZ header extraction based on envelope detection for optical label switching networks is presented. The scheme is insensitive to packet length and spacing and can be single-chip integrated cost-effectively......A simple method for 40 Gbit/s NRZ header extraction based on envelope detection for optical label switching networks is presented. The scheme is insensitive to packet length and spacing and can be single-chip integrated cost-effectively...

Design and Evaluation of IP Header Compression for Cellular-Controlled P2P Networks

DEFF Research Database (Denmark)

Madsen, T.K.; Zhang, Qi; Fitzek, F.H.P.

2007-01-01

In this paper we advocate to exploit terminal cooperation to stabilize IP communication using header compression. The terminal cooperation is based on direct communication between terminals using short range communication and simultaneously being connected to the cellular service access point....... The short range link is than used to provide first aid information to heal the decompressor state of the neighboring node in case of a packet loss on the cellular link. IP header compression schemes are used to increase the spectral and power efficiency loosing robustness of the communication compared...

Procurement and Contracting, Transportation & Public Facilities, State of

Science.gov (United States)

Visiting Alaska State Employees Alaska Department of Transportation & Public Facilities header image Alaska Department of Transportation & Public Facilities / Procurement and Contracting Search DOT& pages Department of Transportation & Public Facilities PO Box 112500 3132 Channel Drive Juneau

Qualifying the use of RIS data for patient dose by comparison with DICOM header data

International Nuclear Information System (INIS)

Wilde, R.; Charnock, P.; McDonald, S.; Moores, B. M.

2011-01-01

A system was developed in 2008 to calculate patient doses using Radiology Information System (RIS) data and presents these data as a patient dose audit. One of the issues with this system was the quality of user-entered data. It has been shown that Digital Imaging and Communication in Medicine (DICOM) header data can be used to perform dose audits with a high level of data accuracy. This study aims to show that using RIS data for dose audits is not only a viable alternative to using DICOM header data, but that it has advantages. A new system was developed to pull header data from DICOM images easily and was installed on a workstation within a hospital department. Data were recovered for a common set of examinations using both RIS and DICOM header data. The data were compared on a result-by-result basis to check for consistency of common fields between RIS and DICOM, as well as assessing the value of data fields uncommon to both systems. The study shows that whilst RIS is not as accurate as DICOM, it does provide enough accurate data and that it has other advantages over using a DICOM approach. These results suggest that a 'best of both worlds' may be achievable using Modality Performed Procedure Step (MPPS). (authors)

Novel Scheme for Packet Forwarding without Header Modifications in Optical Networks

DEFF Research Database (Denmark)

Wessing, Henrik; Christiansen, Henrik Lehrmann; Fjelde, Tina

2002-01-01

We present a novel scheme for packet forwarding in optical packet-switched networks and we further demonstrate its good scalability through simulations. The scheme requires neither header modification nor any label distribution protocol, thus reducing component cost while simplifying network...

A LOCA analysis for AHWR caused by ECCS header rupture

International Nuclear Information System (INIS)

Chatterjee, B.; Gawai, Amol; Gupta, S.K.; Kushwaha, H.S.

2000-01-01

Loss of coolant accident (LOCA) analyses for the proposed 750 MWth Advanced Heavy Water Reactor (AHWR), initiated by the rupture of 8 inch NB ECCS header has been carried out. This paper narrates the description of AHWR and associated ECCS, postulated scenario with which the analyses is carried out, results, discussion and conclusion

A computational fluid dynamics and effectiveness-NTU based co-simulation approach for flow mal-distribution analysis in microchannel heat exchanger headers

International Nuclear Information System (INIS)

Huang, Long; Lee, Moon Soo; Saleh, Khaled; Aute, Vikrant; Radermacher, Reinhard

2014-01-01

Refrigerant flow mal-distribution is a practical challenge in most microchannel heat exchangers (MCHXs) applications. Geometry design, uneven heat transfer and pressure drop in the different microchannel tubes are three main reasons leading to the flow mal-distribution. To efficiently and accurately account for these three effects, a new MCHX co-simulation approach is proposed in this paper. The proposed approach combines a detailed header simulation based on computational fluid dynamics (CFD) and a robust effectiveness-based finite volume tube-side heat transfer and refrigerant flow modeling tool. The co-simulation concept is demonstrated on a ten-tube MCHX case study. Gravity effect and uneven airflow effect were numerically analyzed using both water and condensing R134a as the working fluids. The approach was validated against experimental data for an automotive R134a condenser. The inlet header was cut open after the experimental data had been collected. The detailed header geometry was reproduced using the proposed CFD header model. Good prediction accuracy was achieved compared to the experimental data. The presented co-simulation approach is capable of predicting detailed refrigerant flow behavior while accurately predicts the overall heat exchanger performance. - Highlights: •MCHX header flow distribution is analyzed by a co-simulation approach. •The proposed method is capable of simulating both single-phase and two-phase flow. •An actual header geometry is reproduced in the CFD header model. •The modeling work is experimentally validated with good accuracy. •Gravity effect and air side mal-distribution are accounted for

Damage distribution and remnant life assessment of a super-heater outlet header used for long time

Energy Technology Data Exchange (ETDEWEB)

Hiroyuki, Okamura [Science Univ. of Tokyo (Japan); Ryuichi, Ohotani [Kyoto Univ. (Japan); Kazuya, Fujii [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Masashi, Nakashiro; Fumio, Takemasa; Hideo, Umaki; Tomiyasu, Masumura [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

1998-11-01

This paper presents the results of investigation on evaluating damage distribution to base metals and welded joints in the thickness direction and evaluate damage on ligaments. Thick wall tested sample was the superheater outlet header component long term serviced in high pressure and temperature condition in thermal power plant. The simulate unused steel of component material was made from sample by suitable heat treatment, and the extent of damage was assessed based on a comparison of nondestructive and destructive test results between simulate unused and aged samples. Damage evaluation was also made by FEM structural stress analysis. (orig./MM)

Aviation and Airports, Transportation & Public Facilities, State of Alaska

Science.gov (United States)

State Employees Alaska Department of Transportation & Public Facilities header image Alaska Department of Transportation & Public Facilities / Aviation and Airports Search DOT&PF State of pages view official DOT&PF Flickr pages Department of Transportation & Public Facilities PO Box

Daily Press Headers as a Reinforcement to Brand Identity in Spanish Sport Newspapers both Print and Online

Directory of Open Access Journals (Sweden)

Belén PUEBLA MARTÍNEZ

2015-06-01

Full Text Available Press headers are to daily newspapers the same as brands are to products. Because a newspaper is an object itself which also participates in a double designing process: from information and from product design; and in both cases this serves the same purpose, that the reader feels attracted and comes back for more every day. On that trip, which takes place either to the newsstand or to the computer, to become visible and unique is of paramount importance and the header is the element that best identifies not only the publication but also the tone of the language that the reader expects to find in it. This study intends to dive into the Spanish sport daily press headers, both print and digital, to establish how newspapers achieve their pretended brand identity.

Optimising residual stresses at a repair in a steam header to tubeplate weld

International Nuclear Information System (INIS)

Soanes, T.P.T.; Bell, W.; Vibert, A.J.

2005-01-01

Following the discovery of incorrect weld metal in the steam side shell to tubeplate weld in a type 316H stainless steel superheater steam header, a repair strategy had to be determined. The strategy adopted was to remove the incorrect weld material, which extended around the full circumference, by machining from the inside of the header, followed by rewelding from the inside using an automatic welding process and localised post-weld heat treatment. Due to concern over potential reheat cracking of the repair after return to service, a considerable amount of residual stress modelling was carried out to support the development and optimisation of a successful repair and heat treatment strategy and thus underwrite the safety case for return to service

Summary report on underground road header environmental control.

CSIR Research Space (South Africa)

Belle, BK

2002-01-01

Full Text Available and on monitoring should be reassessed to take into consideration the recent findings and current international trends. 5 6. No conclusive results were obtained with regard to the use of a wet cutter head in conjunction with the Bank 2000 Road Header Dust... this response time interval is lower than the T90 response time, a good indication of the methane gas trends can be obtained. To protect the methane sensors from the harsh environment around an active RH, the 22 Custodian sensors were placed in polycarbonate...

Researching of Covert Timing Channels Based on HTTP Cache Headers in Web API

Directory of Open Access Journals (Sweden)

Denis Nikolaevich Kolegov

2015-12-01

Full Text Available In this paper, it is shown how covert timing channels based on HTTP cache headers can be implemented using different Web API of Google Drive, Dropbox and Facebook  Internet services.

CFD simulation for thermal mixing of a SMART flow mixing header assembly

International Nuclear Information System (INIS)

Kim, Young In; Bae, Youngmin; Chung, Young Jong; Kim, Keung Koo

2015-01-01

Highlights: • Thermal mixing performance of a FMHA installed in SMART is investigated numerically. • Effects of operating condition and discharge hole configuration are examined. • FMHA performance satisfies the design requirements under various abnormal conditions. - Abstract: A flow mixing header assembly (FMHA) is installed in a system-integrated modular advanced reactor (SMART) to enhance the thermal mixing capability and create a uniform core flow distribution under both normal operation and accident conditions. In this study, the thermal mixing characteristics of the FMHA are investigated for various steam generator conditions using a commercial CFD code. Simulations include investigations for the effects of FMHA discharge flow rate differences, turbulence models, and steam generator conditions. The results of the analysis show that the FMHA works effectively for thermal mixing in various conditions and makes the temperature difference at the core inlet decrease noticeably. We verified that the mixing capability of the FMHA is excellent and satisfies the design requirement in all simulation cases tested here

Multiple-output all-optical header processing technique based on two-pulse correlation principle

NARCIS (Netherlands)

Calabretta, N.; Liu, Y.; Waardt, de H.; Hill, M.T.; Khoe, G.D.; Dorren, H.J.S.

2001-01-01

A serial all-optical header processing technique based on a two-pulse correlation principle in a semiconductor laser amplifier in a loop mirror (SLALOM) configuration that can have a large number of output ports is presented. The operation is demonstrated experimentally at a 10Gbit/s Manchester

Fission products transport in CANDU Primary Heat Transport System in a severe accident

International Nuclear Information System (INIS)

Constantin, M.; Rizoiu, A.; Turcu, I.; Negut, Gh.

2005-01-01

Full text: The paper is intended to analyse the distribution of the fission products (FPs) in CANDU Primary Heat Transport (PHT) System by using the ASTEC code (Accident Source Term Evaluation Code). The complexity of the data required by ASTEC and the complexity of CANDU PHT were strong motivation to begin with a simplified geometry in order to avoid the introducing of unmanageable errors at the level of input deck. Thus only 1/4 of the PHT circuit was simulated, an simplified FPs inventory and some simplifications in the feeders geometry were also used. The circuit consists of 95 horizontal fuel channels connected to 95 horizontal out-feeders, then through vertical feeders to the outlet-header (a big pipe that collects the water from feeders); the circuit continues from the outlet-header with a riser and then with the steam generator and a pump. After this pump, the circuit was broken; in this point the FPs are transferred to the containment. The data related to the nodes' definitions, temperatures and pressure conditions were chosen as possible as real data from CANDU NPP loss of coolant accident sequence. Temperature and pressure conditions in the time of the accident were calculated by CATHENA code and the source term of FPs introduced into the PHT was estimated by ORIGEN code. The results consist of mass distributions in the nodes of the circuit and the mass transfer to the containment through the break for different species (FPs and chemical species). The study is completed by sensitivity analysis for the parameters with important uncertainties. (authors)

Asynchronous broadcast for ordered delivery between compute nodes in a parallel computing system where packet header space is limited

Science.gov (United States)

Kumar, Sameer

2010-06-15

Disclosed is a mechanism on receiving processors in a parallel computing system for providing order to data packets received from a broadcast call and to distinguish data packets received at nodes from several incoming asynchronous broadcast messages where header space is limited. In the present invention, processors at lower leafs of a tree do not need to obtain a broadcast message by directly accessing the data in a root processor's buffer. Instead, each subsequent intermediate node's rank id information is squeezed into the software header of packet headers. In turn, the entire broadcast message is not transferred from the root processor to each processor in a communicator but instead is replicated on several intermediate nodes which then replicated the message to nodes in lower leafs. Hence, the intermediate compute nodes become "virtual root compute nodes" for the purpose of replicating the broadcast message to lower levels of a tree.

The effect of the flow direction inside the header on two-phase flow distribution in parallel vertical channels

International Nuclear Information System (INIS)

Marchitto, A.; Fossa, M.; Guglielmini, G.

2012-01-01

Uniform fluid distribution is essential for efficient operation of chemical-processing equipment such as contactors, reactors, mixers, burners and in most refrigeration equipment, where two phases are acting together. To obtain optimum distribution, proper consideration must be given to flow behaviour in the distributor, flow conditions upstream and downstream of the distributor, and the distribution requirements (fluid or phase) of the equipment. Even though the principles of single phase distribution have been well developed for more than three decades, they are frequently not taken in the right account by equipment designers when a mixture is present, and a significant fraction of process equipment consequently suffers from maldistribution. The experimental investigation presented in this paper is aimed at understanding the main mechanisms which drive the flow distribution inside a two-phase horizontal header in order to design improved distributors and to optimise the flow distribution inside compact heat exchanger. Experimentation was devoted to establish the influence of the inlet conditions and of the channel/distributor geometry on the phase/mass distribution into parallel vertical channels. The study is carried out with air–water mixtures and it is based on the measurement of component flow rates in individual channels and on pressure drops across the distributor. The effects of the operating conditions, the header geometry and the inlet port nozzle were investigated in the ranges of liquid and gas superficial velocities of 0.2–1.2 and 1.5–16.5 m/s, respectively. In order to control the main flow direction inside the header, different fitting devices were tested; the insertion of a co-axial, multi-hole distributor inside the header has confirmed the possibility of greatly improving the liquid and gas flow distribution by the proper selection of position, diameter and number of the flow openings between the supplying distributor and the system of

Continuous monitoring of variations in the 235U enrichment of uranium in the header pipework of a centrifuge enrichment plant

International Nuclear Information System (INIS)

Packer, T.W.

1991-01-01

Non-destructive assay equipment, based on gamma-ray spectrometry and x-ray fluorescence analysis has previously been developed for confirming the presence of low enriched uranium in the header pipework of UF 6 gas centrifuge enrichment plants. However inspections can only be carried out occasionally on a limited number of pipes. With the development of centrifuge enrichment technology it has been suggested that more frequent, or ideally, continuous measurements should be made in order to improve safeguards assurance between inspections. For this purpose we have developed non-destructive assay equipment based on continuous gamma-ray spectrometry and x-ray transmission measurements. This equipment is suitable for detecting significant changes in the 235 U enrichment of uranium in the header pipework of new centrifuge enrichment plants. Results are given in this paper of continuous measurements made in the laboratory and also on header pipework of a centrifuge enrichment plant at Capenhurst

Twin header bore welded steam generator for pressurized water reactors

International Nuclear Information System (INIS)

Davies, R.J.; Hirst, B.

1979-01-01

A description is given of a pressurized water reactor (PWR) steam generator concept, several examples of which have been in service for up to fourteen years. Details are given of the highly successful service record of this equipment and the features which have been incorporated to minimize corrosion and deposition pockets. The design employs a vertical U tube bundle carried off two horizontal headers to which the tubes are welded by the Foster Wheeler Power Products (FWPP) bore welding process. The factors to be considered in uprating the design to meet the current operating conditions for a 1000 MW unit are discussed. (author)

Novel scheme for efficient and cost-effective forwarding of packets in optical networks without header modification

DEFF Research Database (Denmark)

Wessing, Henrik; Fjelde, Tina; Christiansen, Henrik Lehrmann

2001-01-01

We present a novel scheme for addressing the outputs in optical packet switches and demonstrate its good scalability. The scheme requires neither header modification nor distribution of routing information to the packet switches, thus reducing optical component count while simplifying network...

Predicting the fidelity of JPEG2000 compressed CT images using DICOM header information

International Nuclear Information System (INIS)

Kim, Kil Joong; Kim, Bohyoung; Lee, Hyunna; Choi, Hosik; Jeon, Jong-June; Ahn, Jeong-Hwan; Lee, Kyoung Ho

2011-01-01

Purpose: To propose multiple logistic regression (MLR) and artificial neural network (ANN) models constructed using digital imaging and communications in medicine (DICOM) header information in predicting the fidelity of Joint Photographic Experts Group (JPEG) 2000 compressed abdomen computed tomography (CT) images. Methods: Our institutional review board approved this study and waived informed patient consent. Using a JPEG2000 algorithm, 360 abdomen CT images were compressed reversibly (n = 48, as negative control) or irreversibly (n = 312) to one of different compression ratios (CRs) ranging from 4:1 to 10:1. Five radiologists independently determined whether the original and compressed images were distinguishable or indistinguishable. The 312 irreversibly compressed images were divided randomly into training (n = 156) and testing (n = 156) sets. The MLR and ANN models were constructed regarding the DICOM header information as independent variables and the pooled radiologists' responses as dependent variable. As independent variables, we selected the CR (DICOM tag number: 0028, 2112), effective tube current-time product (0018, 9332), section thickness (0018, 0050), and field of view (0018, 0090) among the DICOM tags. Using the training set, an optimal subset of independent variables was determined by backward stepwise selection in a four-fold cross-validation scheme. The MLR and ANN models were constructed with the determined independent variables using the training set. The models were then evaluated on the testing set by using receiver-operating-characteristic (ROC) analysis regarding the radiologists' pooled responses as the reference standard and by measuring Spearman rank correlation between the model prediction and the number of radiologists who rated the two images as distinguishable. Results: The CR and section thickness were determined as the optimal independent variables. The areas under the ROC curve for the MLR and ANN predictions were 0.91 (95% CI; 0

Investigating a reduced size real-time transport protocol for low-bandwidth networks

CSIR Research Space (South Africa)

Kakande, JN

2011-09-01

Full Text Available in this work as RTP-Lite, requires investigation. A cyclical approach to compression of the RTP headers was used with different compression cycle patterns for Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) transport. Measurements over...

Transport lattice models of heat transport in skin with spatially heterogeneous, temperature-dependent perfusion

Directory of Open Access Journals (Sweden)

Martin Gregory T

2004-11-01

Full Text Available Abstract Background Investigation of bioheat transfer problems requires the evaluation of temporal and spatial distributions of temperature. This class of problems has been traditionally addressed using the Pennes bioheat equation. Transport of heat by conduction, and by temperature-dependent, spatially heterogeneous blood perfusion is modeled here using a transport lattice approach. Methods We represent heat transport processes by using a lattice that represents the Pennes bioheat equation in perfused tissues, and diffusion in nonperfused regions. The three layer skin model has a nonperfused viable epidermis, and deeper regions of dermis and subcutaneous tissue with perfusion that is constant or temperature-dependent. Two cases are considered: (1 surface contact heating and (2 spatially distributed heating. The model is relevant to the prediction of the transient and steady state temperature rise for different methods of power deposition within the skin. Accumulated thermal damage is estimated by using an Arrhenius type rate equation at locations where viable tissue temperature exceeds 42°C. Prediction of spatial temperature distributions is also illustrated with a two-dimensional model of skin created from a histological image. Results The transport lattice approach was validated by comparison with an analytical solution for a slab with homogeneous thermal properties and spatially distributed uniform sink held at constant temperatures at the ends. For typical transcutaneous blood gas sensing conditions the estimated damage is small, even with prolonged skin contact to a 45°C surface. Spatial heterogeneity in skin thermal properties leads to a non-uniform temperature distribution during a 10 GHz electromagnetic field exposure. A realistic two-dimensional model of the skin shows that tissue heterogeneity does not lead to a significant local temperature increase when heated by a hot wire tip. Conclusions The heat transport system model of the

Development of High Temperature Transport System for Molten Salt

International Nuclear Information System (INIS)

Lee, S. H.; Lee, H. S.; Kim, J. G.

2011-01-01

Pyroprocessing technology is one of the the most promising technologies for the advanced fuel cycle with favorable economic potential and intrinsic proliferation-resistance. The electrorefining process, one of main processes which is composed of pyroprocess to recover the useful elements from spent fuel, is under development at the Korea Atomic Energy Research Institute as a sub process of the pyrochemical treatment of spent PWR fuel. High-temperature molten salt transport technologies are required because a molten salt should be transported from the electrorefiner to electrowiner after the electrorefining process. Therefore, in pyrometallurgical processing, the development of high-temperature molten salt transport technologies is a crucial prerequisite. However, there have been a few transport studies on high-temperature molten salt. In this study, an apparatus for suction transport experiments was designed and constructed for the development of high temperature transport technology for molten salt, and the performance test of the apparatus was performed. And also, predissolution test of the salt was carried out using the reactor with furnace in experimental apparatus

Fabrication of an improved tube-to-pipe header heat exchanger for the Fuel Failure Mockup (FFM) Facility

International Nuclear Information System (INIS)

Prislinger, J.J.; Jones, R.H.

1977-05-01

The procedure used in fabricating an improved tube-to-pipe header heat exchanger for the Fuel Failure Mockup (FFM) Facility is described. Superior performance is accomplished at reduced cost with adherence to the ASME Boiler and Pressure Vessel Code. The techniques used and the method of fabrication are described in detail

The Effect of Temperature on Moisture Transport in Concrete.

Science.gov (United States)

Wang, Yao; Xi, Yunping

2017-08-09

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter D HT , which can be determined by the present test data. The test results indicated that D HT is not a constant but increases linearly with the temperature variation. A material model was developed for D HT based on the experimental results obtained in this study.

Experimental use of road header (AM-50) as face cutting machine for extraction of coal in longwall panel

Energy Technology Data Exchange (ETDEWEB)

Passi, K.K.; Kumar, C.R.; Prasad, P. [DGMS, Dhanbad (India)

2001-07-01

The scope of this paper has been limited to the use of available machines and techniques for attaining higher and more efficient production in underground coal mines. Under certain conditions of strata and higher degree of gassiness, the longwall method with hydraulic sand stowing is the only appropriate method of work for extraction of thick seam. In Moonidih Jitpur Colliery of M/S IISCO, No. 14 seam, Degree III gassy seam, 9.07 m thick, is extracted in multilift system with hydraulic sand stowing. In general, the bottom lift is extracted by Single Ended Ranging Arm Shearer and the middle and top lift are extracted by conventional method. However, in one of the panels spare road header machine was used as face cutting machine in bottom lift, on an experimental basis. This paper presents a successful case study of extraction of bottom lift coal by the longwall method with hydraulic sand stowing using road header (AM 50) as the face cutting machines. 9 figs.

LHCb: Dynamically Adaptive Header Generator and Front-End Source Emulator for a 100 Gbps FPGA Based DAQ

CERN Multimedia

Srikanth, S

2014-01-01

The proposed upgrade for the LHCb experiment envisages a system of 500 Data sources each generating data at 100 Gbps, the acquisition and processing of which is a big challenge even for the current state of the art FPGAs. This requires an FPGA DAQ module that not only handles the data generated by the experiment but also is versatile enough to dynamically adapt to potential inadequacies of other components like the network and PCs. Such a module needs to maintain real time operation while at the same time maintaining system stability and overall data integrity. This also creates a need for a Front-end source Emulator capable of generating the various data patterns, that acts as a testbed to validate the functionality and performance of the Header Generator. The rest of the abstract briefly describes these modules and their implementation. The Header Generator is used to packetize the streaming data from the detectors before it is sent to the PCs for further processing. This is achieved by continuously scannin...

Tube temperature rise limits: Boiling considerations

Energy Technology Data Exchange (ETDEWEB)

Vanderwater, R.G.

1952-03-26

A revision of tube power limits based on boiling considerations was presented earlier. The limits were given on a basis of tube power versus header pressure. However, for convenience of operation, the limits have been converted from tube power to permissible water temperature rise. The permissible {triangle}t`s water are given in this document.

Electronic Monitoring Of Storage And Transport Temperatures Of ...

African Journals Online (AJOL)

Electronic Monitoring Of Storage And Transport Temperatures Of Thermostable Newcastle ... 22) were monitored during storage and transport from vaccine production laboratory in Temeke, Dar es ... EMAIL FULL TEXT EMAIL FULL TEXT

Preliminary Study on the High Temperature Transport System for Molten Salt

International Nuclear Information System (INIS)

Lee, S. H.; Lee, H. S.; Kim, J. G.

2012-01-01

Pyroprocessing technology is one of the the most promising technologies for the advanced fuel cycle with favorable economic potential and intrinsic proliferation-resistance. The electrorefining process, one of main processes is compos- ed of pyroprocess to recover the useful elements from spent fuel, is under development at the Korea Atomic Energy Research Institute as a sub process of the pyrochemical treatment of spent PWR fuel. High-temperature molten salt transport technologies are required because a molten salt should be transported from the electrorefiner to electrowiner after the electrorefining process. Therefore, in pyroprocessing technology, the development of high-temperature transport technologies for molten salt is a crucial prerequisite. However, there have been a few transport studies on high-temperature molten salt. In this study, an apparatus for suction transport experiments was designed and constructed for the development of high temperature molten salt transport technology. Suction transport experiments were performed using LiC-KCl eutectic salt

Energy-filtered cold electron transport at room temperature.

Science.gov (United States)

Bhadrachalam, Pradeep; Subramanian, Ramkumar; Ray, Vishva; Ma, Liang-Chieh; Wang, Weichao; Kim, Jiyoung; Cho, Kyeongjae; Koh, Seong Jin

2014-09-10

Fermi-Dirac electron thermal excitation is an intrinsic phenomenon that limits functionality of various electron systems. Efforts to manipulate electron thermal excitation have been successful when the entire system is cooled to cryogenic temperatures, typically distribution corresponds to an effective electron temperature of ~45 K, can be transported throughout device components without external cooling. This is accomplished using a discrete level of a quantum well, which filters out thermally excited electrons and permits only energy-suppressed electrons to participate in electron transport. The quantum well (~2 nm of Cr2O3) is formed between source (Cr) and tunnelling barrier (SiO2) in a double-barrier-tunnelling-junction structure having a quantum dot as the central island. Cold electron transport is detected from extremely narrow differential conductance peaks in electron tunnelling through CdSe quantum dots, with full widths at half maximum of only ~15 mV at room temperature.

Integrated heat transport simulation of high ion temperature plasma of LHD

International Nuclear Information System (INIS)

Murakami, S.; Yamaguchi, H.; Sakai, A.

2014-10-01

A first dynamical simulation of high ion temperature plasma with carbon pellet injection of LHD is performed by the integrated simulation GNET-TD + TASK3D. NBI heating deposition of time evolving plasma is evaluated by the 5D drift kinetic equation solver, GNET-TD and the heat transport of multi-ion species plasma (e, H, He, C) is studied by the integrated transport simulation code, TASK3D. Achievement of high ion temperature plasma is attributed to the 1) increase of heating power per ion due to the temporal increase of effective charge, 2) reduction of effective neoclassical transport with impurities, 3) reduction of turbulence transport. The reduction of turbulence transport is most significant contribution to achieve the high ion temperature and the reduction of the turbulent transport from the L-mode plasma (normal hydrogen plasma) is evaluated to be a factor about five by using integrated heat transport simulation code. Applying the Z effective dependent turbulent reduction model we obtain a similar time behavior of ion temperature after the C pellet injection with the experimental results. (author)

Temperature gradient driven electron transport in NSTX and Tore Supra

International Nuclear Information System (INIS)

Horton, W.; Wong, H.V.; Morrison, P.J.; Wurm, A.; Kim, J.H.; Perez, J.C.; Pratt, J.; Hoang, G.T.; LeBlanc, B.P.; Ball, R.

2005-01-01

Electron thermal fluxes are derived from the power balance for Tore Supra (TS) and NSTX discharges with centrally deposited fast wave electron heating. Measurements of the electron temperature and density profiles, combined with ray tracing computations of the power absorption profiles, allow detailed interpretation of the thermal flux versus temperature gradient. Evidence supporting the occurrence of electron temperature gradient turbulent transport in the two confinement devices is found. With control of the magnetic rotational transform profile and the heating power, internal transport barriers are created in TS and NSTX discharges. These partial transport barriers are argued to be a universal feature of transport equations in the presence of invariant tori that are intrinsic to non-monotonic rotational transforms in dynamical systems

Evaluation of fatigue crack growth and fracture resistance of SA350 LF2 material

International Nuclear Information System (INIS)

Singh, P.K.; Dubey, J.S.; Chakrabarty, J.K.; Vaze, K.K.; Kushwaha, H.S.

2003-01-01

The aim of the present paper is to evaluate the tensile and fracture mechanics properties of the SA350 LF2 carbon steel material used as the Header material in the primary heat transport (PHT) system piping of the Indian pressurized heavy water reactors (PHWR). Tensile, fatigue crack growth rate and fracture toughness tests have been carried out on specimens machined from the Header of the actual PHT pipes. The effect of temperature on tensile properties has been discussed. The effect of temperature and notch orientation on fracture resistance behavior of the material and fatigue crack growth rate dependence on the notch orientation and stress ratio has also been discussed. (author)

Air Emission Projections During Acid Cleaning of F-Canyon Waste Header No.2

International Nuclear Information System (INIS)

CHOI, ALEXANDER

2004-01-01

The purpose of this study was to develop the air emission projections for the maintenance operation to dissolve and flush out the scale material inside the F-Canyon Waste Header No.2. The chemical agent used for the dissolution is a concentrated nitric acid solution, so the pollutant of concern is the nitric acid vapor. Under the very conservative operating scenarios considered in this study, it was determined that the highest possible rate of nitric acid emission during the acid flush would be 0.048 lb. per hr. It turns out that this worst-case air emission projection is just below the current exemption limit of 0.05 lb. per hr. for permit applications

Development of High-Temperature Transport System for Molten Salt in Pyroprocessing

International Nuclear Information System (INIS)

Lee, Sung Ho; Kim, In Tae; Park, Sung Bin

2014-01-01

The electrorefining process, which is a key process in pyroprocessing, is composed of two parts, electrorefining to deposit a uranium with a solid cathode and electrowinning to co-deposit TRU and RE with a liquid cadmium cathode (LCC). As the electrorefining operation proceedes, TRU and RE are accumulated in electrolyte LiCl-KCl salt, and after the electrorefining process, the molten salt used in an electrorefining reactor should by transported to the next process, the electrowinning process, to recover U/TRU/RE; Thus, a molten salt transfer system by suction is now being developed. An apparatus for suction transport experiments was designed and constructed for the development of high- temperature molten salt transport technology. Suction transport experiments were performed using LiC-KCl eutectic salt. The feasibility of pyro-reprocessing has been demonstrated through many laboratory-scale experiments. In pyroprocessing, a eutectic LiCl-KCl salt was used as a liquid elextrolyte for a recovery of actinides. However, reliable transport technologies for these high temperature liquids have not yet been developed. A preliminary study on high-temperature transport technology for molten salt by suction is now being carried out. In this study, three different salt transport technologies (gravity, suction pump, and centrifugal pump) were investigated to select the most suitable method for molten salt transport. An apparatus for suction transport experiments was designed and installed for the development of high-temperature molten salt transport technology. Basic preliminary suction transport experiments were carried out using the prepared LiC-KCl eutectic salt at 500 .deg. C to observe the transport behavior of LiCl-KCl molten salt. In addition, a PRIDE salt transport system was designed and installed for an engineering-scale salt transport demonstration. Several types of suction transport experiments using molten salt (LiCl-KCl eutectics) for the development of a high-temperature

Development of High-Temperature Transport System for Molten Salt in Pyroprocessing

Energy Technology Data Exchange (ETDEWEB)

Lee, Sung Ho; Kim, In Tae; Park, Sung Bin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The electrorefining process, which is a key process in pyroprocessing, is composed of two parts, electrorefining to deposit a uranium with a solid cathode and electrowinning to co-deposit TRU and RE with a liquid cadmium cathode (LCC). As the electrorefining operation proceedes, TRU and RE are accumulated in electrolyte LiCl-KCl salt, and after the electrorefining process, the molten salt used in an electrorefining reactor should by transported to the next process, the electrowinning process, to recover U/TRU/RE; Thus, a molten salt transfer system by suction is now being developed. An apparatus for suction transport experiments was designed and constructed for the development of high- temperature molten salt transport technology. Suction transport experiments were performed using LiC-KCl eutectic salt. The feasibility of pyro-reprocessing has been demonstrated through many laboratory-scale experiments. In pyroprocessing, a eutectic LiCl-KCl salt was used as a liquid elextrolyte for a recovery of actinides. However, reliable transport technologies for these high temperature liquids have not yet been developed. A preliminary study on high-temperature transport technology for molten salt by suction is now being carried out. In this study, three different salt transport technologies (gravity, suction pump, and centrifugal pump) were investigated to select the most suitable method for molten salt transport. An apparatus for suction transport experiments was designed and installed for the development of high-temperature molten salt transport technology. Basic preliminary suction transport experiments were carried out using the prepared LiC-KCl eutectic salt at 500 .deg. C to observe the transport behavior of LiCl-KCl molten salt. In addition, a PRIDE salt transport system was designed and installed for an engineering-scale salt transport demonstration. Several types of suction transport experiments using molten salt (LiCl-KCl eutectics) for the development of a high-temperature

CFD analysis of moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor

International Nuclear Information System (INIS)

Kansal, Anuj Kumar; Joshi, Jyeshtharaj B.; Maheshwari, Naresh Kumar; Vijayan, Pallippattu Krishnan

2015-01-01

Highlights: • 3D CFD of vertical calandria vessel. • Spatial distribution of volumetric heat generation. • Effect of Archimedes number. • Non-dimensional analysis. - Abstract: Three dimensional computational fluid dynamics (CFD) analysis has been performed for the moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor under normal operating condition using OpenFOAM CFD code. OpenFOAM is validated by comparing the predicted results with the experimental data available in literature. CFD model includes the calandria vessel, calandria tubes, inlet header and outlet header. Analysis has been performed for the cases of uniform and spatial distribution of volumetric heat generation. Studies show that the maximum temperature in moderator is lower in the case of spatial distribution of heat generation as compared to that in the uniform heat generation in calandria. In addition, the effect of Archimedes number on maximum and average moderator temperature was investigated

CFD analysis of moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Kansal, Anuj Kumar, E-mail: akansal@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Joshi, Jyeshtharaj B., E-mail: jbjoshi@gmail.com [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Maheshwari, Naresh Kumar, E-mail: nmahesh@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Vijayan, Pallippattu Krishnan, E-mail: vijayanp@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2015-06-15

Highlights: • 3D CFD of vertical calandria vessel. • Spatial distribution of volumetric heat generation. • Effect of Archimedes number. • Non-dimensional analysis. - Abstract: Three dimensional computational fluid dynamics (CFD) analysis has been performed for the moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor under normal operating condition using OpenFOAM CFD code. OpenFOAM is validated by comparing the predicted results with the experimental data available in literature. CFD model includes the calandria vessel, calandria tubes, inlet header and outlet header. Analysis has been performed for the cases of uniform and spatial distribution of volumetric heat generation. Studies show that the maximum temperature in moderator is lower in the case of spatial distribution of heat generation as compared to that in the uniform heat generation in calandria. In addition, the effect of Archimedes number on maximum and average moderator temperature was investigated.

Coupled heat transfer in high temperature transporting system with semitransparent/opaque material

International Nuclear Information System (INIS)

Du Shenghua; Xia Xinjin

2010-01-01

The heat transfer model of the aerodynamic heating coupled with radiative cooling was developed. The thermal protect system includes the higher heat flux region with high temperature semitransparent material, the heat transporting channel and the lower heat flux region with metal. The control volume method was combined with the Monte Carlo method to calculate the coupled heat transfer of the transporting system, and the thermal equilibrium equation for the transporting channel was solved simultaneously. The effect of the aeroheating flux radio, the area ratio of radiative surfaces, the convective heat transfer coefficient of the heat transporting channel on the radiative surface temperature and the fluid temperature in the heat transporting channel were analyzed. The effect of radiation and conduction in the semitransparent material was discussed. The result shows that to increase the convective heat transfer coefficient in heat flux channel can enhance the heat transporting ability of the system, but the main parameter to effect on the temperature of the heat transporting system is the area ratio of radiative surfaces. (authors)

Temperature dependent charge transport in poly(3-hexylthiophene) diodes

Science.gov (United States)

Rahaman, Abdulla Bin; Sarkar, Atri; Banerjee, Debamalya

2018-04-01

In this work, we present charge transport properties of poly(3-hexylthiophene) (P3HT) diodes under dark conditions. Temperature dependent current-voltage (J-V) characteristics shows that charge transport represents a transition from ohomic to trap limited current. The forward current density obeys a power law J˜Vm, m>2 represents the space charge limited current region in presence of traps within the band gap. Frequency dependent conductivity has been studied in a temperature range 150K-473K. The dc conductivity values show Arrhenius like behavior and it gives conductivity activation energy 223 meV. Temperature dependent conductivity indicates a thermodynamic transition of our system.

Thermal-hydraulic analysis of Ignalina NPP compartments response to group distribution header rupture using RALOC4 code

International Nuclear Information System (INIS)

Urbonavicius, E.

2000-01-01

The Accident Localisation System (ALS) of Ignalina NPP is a containment of pressure suppression type designed to protect the environment from the dangerous impact of the radioactivity. The failure of ALS could lead to contamination of the environment and prescribed public radiation doses could be exceeded. The purpose of the presented analysis is to perform long term thermal-hydraulic analysis of compartments response to Group Distribution Header rupture and verify if design pressure values are not exceeded. (authors)

High temperature performance limit of containment system of transport cask

International Nuclear Information System (INIS)

Kato, Osamu; Saegusa, Toshiari

1998-01-01

The containment performance of a containment system using elastomer gaskets for transport casks under a high temperature and high pressure was clarified. Major results are as follows; (1) The deformation characteristics of the gaskets were represented by the compressive permanent strain rate (Dp). The temperature and time dependence was shown by Larson-Miller Parameter (LMP). (2) Generally, the high temperature performance limit is obtained by a value of LMP when the Dp value reaches 80%. However, the gaskets (FKM, VMQ, EPDM) used for real transport casks were not damaged and the containment performance was not deteriorated as a conservative condition. (3) Assuming that the service period of the gaskets for transport casks is 3 months or 1 year, the high temperature performance limit of the gasket made of fluorine rubber (FKM) is 202degC or 182degC, respectively, which includes safety margin. (author)

Modelling of Temperature Profiles and Transport Scaling in Auxiliary Heated Tokamaks

DEFF Research Database (Denmark)

Callen, J.D.; Christiansen, J.P.; Cordey, J.G.

1987-01-01

time , the heating effectiveness η, and the energy offset W(0). Considering both the temperature profile responses and the global transport scaling, the constant heat pinch or excess temperature gradient model is found to best characterize the present JET data. Finally, new methods are proposed......The temperature profiles produced by various heating profiles are calculated from local heat transport models. The models take the heat flux to be the sum of heat diffusion and a non-diffusive heat flow, consistent with local measurements of heat transport. Two models are developed analytically...... in detail: (i) a heat pinch or excess temperature gradient model with constant coefficients; and (ii) a non-linear heat diffusion coefficient (χ) model. Both models predict weak (lesssim20%) temperature profile responses to physically relevant changes in the heat deposition profile – primarily because...

Design and analysis of reactor headers for Narora Atomic Power Project

International Nuclear Information System (INIS)

Danak, M.R.

1975-01-01

Reactor header for Narora Atomic Power Reactor is a 400 mm O.D. 10 metres long pressure vessel in the primary coolant circuit connecting 153 feeders to PHT pumps or steam generators. The vessel dimensions are restricted are by containment philosophy. The outlet connections for pumps or steam generators are to be of the size of vessel diameter and DO/t ratio for the vessel is approximately 10. The design and stresses induced meet the code requirements except that at times it is difficult to get precise stress values in absence of certain data and lack of code or available literature giving practical approach to the problem. It can be seen that the 400 mm equal tees used as part of the vessel cannot be penetrated in the light of code reinforcement requirements. However if the tees have to penetrated to retain established feeder layout, it should be established experimentally or by some detailed stress analysis that it will meet the intent of code. (author)

Reducing CO2 emissions in temperature-controlled road transportation using the LDVRP model

NARCIS (Netherlands)

Stellingwerf, Helena M.; Kanellopoulos, Argyris; Vorst, van der Jack G.A.J.; Bloemhof, Jacqueline M.

2018-01-01

Temperature-controlled transport is needed to maintain the quality of products such as fresh and frozen foods and pharmaceuticals. Road transportation is responsible for a considerable part of global emissions. Temperature-controlled transportation exhausts even more emissions than ambient

Theory-based transport simulations of TFTR L-mode temperature profiles

International Nuclear Information System (INIS)

Bateman, G.

1991-01-01

The temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient (η i ) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the periphery. Within the context of this transport model and the TFTR simulations reported here, the scaling of confinement with heating power comes from the temperature dependence of the η i and trapped electron modes, while the scaling with current comes mostly from resistive ballooning modes. 24 refs., 16 figs., 3 tabs

Body temperature change and outcomes in patients undergoing long-distance air medical transport.

Science.gov (United States)

Nakajima, Mikio; Aso, Shotaro; Yasunaga, Hideo; Shirokawa, Masamitsu; Nakano, Tomotsugu; Miyakuni, Yasuhiko; Goto, Hideaki; Yamaguchi, Yoshihiro

2018-04-30

Short-distance air medical transport for adult emergency patients does not significantly affect patients' body temperature and outcomes. This study aimed to examine the influence of long-distance air medical transport on patients' body temperatures and the relationship between body temperature change and mortality. We retrospectively enrolled consecutive patients transferred via helicopter or plane from isolated islands to an emergency medical center in Tokyo, Japan between April 2010 and December 2016. Patients' average body temperature was compared before and after air transport using a paired t-test, and corrections between body temperature change and flight duration were calculated using Pearson's correlation coefficient. Multivariable logistic regression models were then used to examine the association between body temperature change and in-hospital mortality. Of 1253 patients, the median age was 72 years (interquartile range, 60-82 years) and median flight duration was 71 min (interquartile range, 54-93 min). In-hospital mortality was 8.5%, and average body temperature was significantly different before and after air transport (36.7 °C versus 36.3 °C; difference: -0.36 °C; 95% confidence interval, -0.30 to -0.42; p 38.0 °C) or normothermia (36.0-37.9 °C) before air transport and hypothermia after air transport (odds ratio, 2.08; 95% confidence interval, 1.20-3.63; p = 0.009), and (ii) winter season (odds ratio, 2.15; 95% confidence interval, 1.08-4.27; p = 0.030). Physicians should consider body temperature change during long-distance air transport in patients with not only hypothermia but also normothermia or hyperthermia before air transport, especially in winter. Copyright © 2018 Elsevier Inc. All rights reserved.

Establishing Bedding Requirements during Transport and Monitoring Skin Temperature during Cold and Mild Seasons after Transport for Finishing Pigs

Directory of Open Access Journals (Sweden)

John McGlone

2014-05-01

Full Text Available The broad aim of this study was to determine whether bedding level in the transport trailer influenced pig performance and welfare. Specifically, the objective was to define the bedding requirements of pigs during transportation in commercial settings during cold and mild weather. Animals (n = 112,078 pigs on 572 trailers used were raised in commercial finishing sites and transported in trailers to commercial processing plants. Dead on arrival (DOA, non-ambulatory (NA, and total dead and down (D&D data were collected and skin surface temperatures of the pigs were measured by infrared thermography. Data were collected during winter (Experiment 1 and fall/spring (Experiment 2. Total D&D percent showed no interaction between bedding level and outside air temperature in any experiments. Average skin surface temperature during unloading increased with outside air temperature linearly in both experiments (P < 0.01. In conclusion, over-use of bedding may be economically inefficient. Pig skin surface temperature could be a useful measure of pig welfare during or after transport.

Dense high-temperature plasma transport processes

International Nuclear Information System (INIS)

Giniyatova, Sh.G.

2002-01-01

In this work the transport processes in dense high-temperature semiclassical plasma are studied on the base of the kinetic equation, where the semiclassical potential was used, in its collision integral. The coefficient of plasma electrical conductivity, viscosity and thermal conductivity were received. There were compared with the other authors' results. The Grad's method was used obtaining of viscosity and thermal coefficients. (author)

Low-temperature transport in out-of-equilibrium XXZ chains

Science.gov (United States)

Bertini, Bruno; Piroli, Lorenzo

2018-03-01

We study the low-temperature transport properties of out-of-equilibrium XXZ spin-1/2 chains. We consider the protocol where two semi-infinite chains are prepared in two thermal states at small but different temperatures and suddenly joined together. We focus on the qualitative and quantitative features of the profiles of local observables, which at large times t and distances x from the junction become functions of the ratio \\zeta=x/t . By means of the generalized hydrodynamic equations, we analyse the rich phenomenology arising by considering different regimes of the phase diagram. In the gapped phases, variations of the profiles are found to be exponentially small in the temperatures, but described by non-trivial functions of ζ. We provide analytical formulae for the latter, which give accurate results also for small but finite temperatures. In the gapless regime, we show how the three-step conformal predictions for the profiles of energy density and energy current are naturally recovered from the hydrodynamic equations. Moreover, we also recover the recent non-linear Luttinger liquid predictions for low-temperature transport: universal peaks of width \

Pacemaker syndrome with sub-acute left ventricular systolic dysfunction in a patient with a dual-chamber pacemaker: consequence of lead switch at the header.

Science.gov (United States)

Khurwolah, Mohammad Reeaze; Vezi, Brian Zwelethini

In the daily practice of pacemaker insertion, the occurrence of atrial and ventricular lead switch at the pacemaker box header is a rare and unintentional phenomenon, with less than five cases reported in the literature. The lead switch may have dire consequences, depending on the indication for the pacemaker. One of these consequences is pacemaker syndrome, in which the normal sequence of atrial and ventricular activation is impaired, leading to sub-optimal ventricular filling and cardiac output. It is important for the attending physician to recognise any worsening of symptoms in a patient who has recently had a permanent pacemaker inserted. In the case of a dual-chamber pacemaker, switching of the atrial and ventricular leads at the pacemaker box header should be strongly suspected. We present an unusual case of pacemaker syndrome and right ventricular-only pacinginduced left ventricular systolic dysfunction in a patient with a dual-chamber pacemaker.

Temperature dependence of electronic transport property in ferroelectric polymer films

Energy Technology Data Exchange (ETDEWEB)

Zhao, X.L.; Wang, J.L., E-mail: jlwang@mail.sitp.ac.cn; Tian, B.B.; Liu, B.L.; Zou, Y.H.; Wang, X.D.; Sun, S.; Sun, J.L., E-mail: jlsun@mail.sitp.ac.cn; Meng, X.J.; Chu, J.H.

2014-10-15

Highlights: • The ferroelectric polymer was fabricated by Langmuir–Blodgett method. • The electrons as the dominant injected carrier were conformed in the ferroelectric polymer films. • The leakage current conduction mechanisms in ferroelectric polymer were investigated. - Abstract: The leakage current mechanism of ferroelectric copolymer of polyvinylidene fluoride with trifluoroethylene prepared by Langmuir–Blodgett was investigated in the temperature range from 100 K to 350 K. The electron as the dominant injected carrier was observed in the ferroelectric copolymer films. The transport mechanisms in copolymer strongly depend on the temperature and applied voltage. From 100 K to 200 K, Schottky emission dominates the conduction. With temperature increasing, the Frenkel–Poole emission instead of the Schottky emission to conduct the carrier transport. When the temperature gets to 260 K, the leakage current becomes independent of temperature, and the space charge limited current conduction was observed.

All-Cause and Cause-Specific Risk of Emergency Transport Attributable to Temperature

Science.gov (United States)

Onozuka, Daisuke; Hagihara, Akihito

2015-01-01

Abstract Although several studies have estimated the associations between mortality or morbidity and extreme temperatures in terms of relative risk, few studies have investigated the risk of emergency transport attributable to the whole temperature range nationwide. We acquired data on daily emergency ambulance dispatches in all 47 prefectures of Japan from 2007 to 2010. We examined the relationship between emergency transport and temperature for each prefecture using a Poisson regression model in a distributed lag nonlinear model with adjustment for time trends. A random-effect multivariate meta-analysis was then applied to pool the estimates at the national level. Attributable morbidity was calculated for high and low temperatures, which were defined as those above or below the optimum temperature (ie, the minimum morbidity temperature) and for moderate and also extreme temperatures, which were defined using cutoffs at the 2.5th and 97.5th temperature percentiles. A total of 15,868,086 cases of emergency transport met the inclusion criteria. The emergency transport was attributable to nonoptimal temperature. The median minimum morbidity percentile was in the 79th percentile for all causes, the 96th percentile for cardiovascular disease, and the 92th percentile for respiratory disease. The fraction attributable to low temperature was 6.94% (95% eCI: 5.93–7.70) for all causes, 17.93% (95% eCI: 16.10–19.25) for cardiovascular disease, and 12.19% (95% eCI: 9.90–13.66) for respiratory disease, whereas the fraction attributable to high temperature was small (all causes = 1.01%, 95% eCI: 0.90–1.11; cardiovascular disease = 0.10%, 95% eCI: 0.04–0.14; respiratory disease = 0.29%, 95% eCI: 0.07–0.50). The all-cause morbidity risk that was attributable to temperature was related to moderate cold, with an overall estimate of 6.41% (95% eCI: 5.47–7.20). Extreme temperatures were responsible for a small fraction, which corresponded to 0.57% (95% e

Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

Science.gov (United States)

Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

2014-12-01

Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

Energy Technology Data Exchange (ETDEWEB)

Smedley-Stevenson, Richard P., E-mail: richard.smedley-stevenson@awe.co.uk [AWE PLC, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom); Department of Earth Science and Engineering, Imperial College London, SW7 2AZ (United Kingdom); McClarren, Ryan G., E-mail: rmcclarren@ne.tamu.edu [Department of Nuclear Engineering, Texas A & M University, College Station, TX 77843-3133 (United States)

2015-04-01

This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes.

Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

International Nuclear Information System (INIS)

Smedley-Stevenson, Richard P.; McClarren, Ryan G.

2015-01-01

This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes

Brittle fracture tests at low temperature for transport cask materials

International Nuclear Information System (INIS)

Kosaki, Akio; Ito, Chihiro; Arai, Taku; Saegusa, Toshiari

1993-01-01

The IAEA Regulations for the Safe Transport of Radioactive Material were revised in 1985, and brittle fracture assessment at low temperature for transport packages are now required. This report discusses the applicability of the actual method for brittle fracture assessment of type-B transport cask materials used in JAPAN. The necessity of brittle fracture assessment at low temperature was estimated for each material of type-B transport casks used in Japan and the applicability was investigated. Dynamic fracture toughness values, K Id (J Id ), and RT NDT values of Low-Mn Carbon Steels, that are SA 350 Gr.LF1 Modify and SA 516 Gr.70 material which used in type-B transport cask body, were also obtained to check whether or not an easier and conventional test method, that prescribed in ASME CODE SECTION III, can be substituted for the dynamic fracture test method. And for bolt materials, which include 1.8Ni-0.8Cr-0.3Mo Carbon Steel and type 630 H Stainless Steel, toughness data were obtained for reference. (J.P.N.)

Thermodynamic and transport properties of two-temperature SF6 plasmas

International Nuclear Information System (INIS)

Wang Weizong; Rong Mingzhe; Wu Yi; Spencer, Joseph W.; Yan, Joseph D.; Mei, DanHua

2012-01-01

This paper deals with thermodynamic and transport properties of SF 6 plasmas in a two-temperature model for both thermal equilibrium and non-equilibrium conditions. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and Guldberg-Waage equation according to deviation of van de Sanden et al. Transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated with most recent collision interaction potentials by adopting Devoto’s electron and heavy particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of Chapman–Enskog method. The results are computed for various values of pressures from 0.1 atm to 10 atm and ratios of the electron temperature to the heavy particle temperature from 1 to 20 with electron temperature range from 300 to 40 000 K. In the local thermodynamic equilibrium regime, results are compared with available results of previously published studies.

Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

International Nuclear Information System (INIS)

Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie; Gu, Changzhi

2014-01-01

B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3 K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63 nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity

Design considerations for CRBRP heat transport system piping operating at elevated temperatures

International Nuclear Information System (INIS)

Pollono, L.P.; Mello, R.M.

1979-01-01

The heat transport system sodium piping for the Clinch River Breeder Reactor Plant (CRBRP) within the reactor containment building must withstand high temperatures for long periods of time. Each phase of the mechanical design process of the piping system is influenced by elevated temperature considerations which include material thermal creep effects, ratchetting caused by rapid temperature transients and stress relaxation, and material degradation effects. The structural design philosophy taken to design the CRBRP piping operating in a high temperature environment is described. The resulting design of the heat transport system piping is presented along with a discussion of special features that resulted from the elevated temperature considerations

Temperature-dependent charge transport mechanisms in carbon sphere/polyaniline composite

Science.gov (United States)

Nieves, Cesar A.; Martinez, Luis M.; Meléndez, Anamaris; Ortiz, Margarita; Ramos, Idalia; Pinto, Nicholas J.; Zimbovskaya, Natalya

2017-12-01

Charge transport in the temperature range 80 K electrons between polymeric chains in PANi-filled gaps between CS is the predominant transport mechanism through CS/PANi composites. The high conductivity of the CS/PANi composite makes the material attractive for the fabrication of devices and sensors.

Room-temperature ballistic transport in III-nitride heterostructures.

Science.gov (United States)

Matioli, Elison; Palacios, Tomás

2015-02-11

Room-temperature (RT) ballistic transport of electrons is experimentally observed and theoretically investigated in III-nitrides. This has been largely investigated at low temperatures in low band gap III-V materials due to their high electron mobilities. However, their application to RT ballistic devices is limited by their low optical phonon energies, close to KT at 300 K. In addition, the short electron mean-free-path at RT requires nanoscale devices for which surface effects are a limitation in these materials. We explore the unique properties of wide band-gap III-nitride semiconductors to demonstrate RT ballistic devices. A theoretical model is proposed to corroborate experimentally their optical phonon energy of 92 meV, which is ∼4× larger than in other III-V semiconductors. This allows RT ballistic devices operating at larger voltages and currents. An additional model is described to determine experimentally a characteristic dimension for ballistic transport of 188 nm. Another remarkable property is their short carrier depletion at device sidewalls, down to 13 nm, which allows top-down nanofabrication of very narrow ballistic devices. These results open a wealth of new systems and basic transport studies possible at RT.

Effect of transportation during periods of high ambient temperature on physiologic and behavioral indices of beef heifers.

Science.gov (United States)

Theurer, Miles E; White, Brad J; Anderson, David E; Miesner, Matt D; Mosier, Derek A; Coetzee, Johann F; Amrine, David E

2013-03-01

To determine the effect of transportation during periods of high ambient temperature on physiologic and behavioral indices of beef heifers. 20 heifers (mean body weight, 217.8 kg). Ten heifers were transported 518 km when the maximum ambient temperature was ≥ 32.2°C while the other 10 heifers served as untransported controls. Blood samples were collected from transported heifers at predetermined intervals during the transportation period. For all heifers, body weights, nasal and rectal temperatures, and behavioral indices were measured at predetermined intervals for 3 days after transportation. A week later, the entire process was repeated such that each group was transported twice and served as the control twice. Transported heifers spent more time near the hay feeder on the day of transportation, had lower nasal and rectal temperatures for 24 hours after transportation, and spent more time lying down for 2 days after transportation, compared with those indices for control heifers. Eight hours after transportation, the weight of transported heifers decreased 6%, whereas that of control heifers increased 0.6%. At 48 hours after initiation of transportation, weight, rectal temperature, and time spent at various pen locations did not differ between transported and control heifers. Cortisol concentrations were higher 4 hours after initiation of transportation, compared with those determined just prior to transportation. Results indicated transportation during periods of high ambient temperatures caused transient changes in physiologic and behavioral indices of beef heifers.

Lower air temperature is associated with ambulance transports and death in Takamatsu area, Japan.

Science.gov (United States)

Mochimasu, Kazumi Dokai; Miyatake, Nobuyuki; Tanaka, Naoko; Kinoshita, Hiroshi

2014-07-01

The aim of this study was to investigate the linkage among ambulance transports, the number of death and air temperature in Takamatsu area, Japan. Monthly data of ambulance transports (total and acute disease) and the number of death from 2004 to 2012 were obtained from Fire Department Service in Takamatsu and Takamatsu city official website, Japan. Climate parameters for required period were also obtained from Japan Meteorological Agency. Population data in Takamatsu area were also used to adjust ambulance transports and the number of death. The linkage among ambulance transports, the number of death and climate parameters was evaluated by ecological analysis. Total ambulance transports (/a hundred thousand people/day) and ambulance transports due to acute disease (/a hundred thousand people/day) were 12.3 ± 0.9 and 6.8 ± 0.7, respectively. The number of death (/a hundred thousand people/day) was 2.5 ± 0.4. By quadratic curve, ambulance transports due to acute disease and the number of death were significantly correlated with the parameters of air temperature. However, the number of death was the highest in January and the lowest in August. Although higher air temperature was only associated with higher ambulance transports, lower air temperature was associated with both higher ambulance transports and the number death in Takamatsu area, Japan.

Effects of sorption and temperature on solute transport in unsaturated steady flow

International Nuclear Information System (INIS)

Fuentes, H.R.; Polzer, W.L.; Essington, E.H.

1986-01-01

It is known that temperature affects physical and chemical processes and that these processes may alter the transport of solutes in the environment. Laboratory column studies were performed in unsaturated flow conditions with a composite pulse containing iodide, cobalt, cesium and strontium each at 10 -3 M. The experiments were performed with Bandelier Tuff and produced breakthrough curves that indicate significant changes in transport due to a temperature change from 25 0 C to 5 0 C for nonconservative solutes. Also, the interpretation of the temperature and sorption data suggest that the differences in transport between 5 0 C and 25 0 C for nonconservative solutes may be predicted in a qualitative manner from batch equilibrium and nonequilibrium sorption data and the theory of sorption used in deriving the modified Freundlich isotherm equation. These effects should be of concern in modeling and management of spills and waste disposal within this range of environmental temperatures

Temperature driven transport of gold nanoparticles physisorbed inside carbon nanotubes

DEFF Research Database (Denmark)

Schoen, P.A.E.; Poulikakos, D.; Walther, Jens Honore

2006-01-01

We use molecular dynamics simulations to demonstrate the temperature driven mass transport of solid gold nanoparticles, physisorbed inside carbon nanotubes (CNTs). Our results indicate that the nanoparticle experiences a guided motion, in the direction opposite to the direction of the temperature...... affects the nanoparticle motion along the carbon lattice....

Anomalous plasma transport due to electron temperature gradient instability

International Nuclear Information System (INIS)

Tokuda, Sinji; Ito, Hiroshi; Kamimura, Tetsuo.

1979-01-01

The collisionless drift wave instability driven by an electron temperature inhomogeneity (electron temperature gradient instability) and the enhanced transport processes associated with it are studied using a two-and-a-half dimensional particle simulation code. The simulation results show that quasilinear diffusion in phase space is an important mechanism for the saturation of the electron temperature gradient instability. Also, the instability yields particle fluxes toward the hot plasma regions. The heat conductivity of the electron temperature perpendicular to the magnetic field, T sub(e'), is not reduced by magnetic shear but remains high, whereas the heat conductivity of the parallel temperature, T sub(e''), is effectively reduced, and the instability stabilized. (author)

Practical reasons for investigating ion transport in high temperature insulating materials

International Nuclear Information System (INIS)

Sonder, E.

1976-01-01

Practical problems encountered in a number of advanced technology appliations, particularly those related to energy conversion, are discussed. Refractory ionic compounds which are abundant and of high melting point are listed, and technological problems are discussed in terms of specific materials problems. The argument is made that basic information concerning transport properties in refractory compounds is lacking to such an extent that it is difficult to design and assess advanced energy generation systems. Technology applications include: a) ceramic nuclear fuels for high temperature fission reactors, b) high temperature gas turbine blades, c) insulators in controlled thermonuclear reactors, and d) magnetohydrodynamic generators. Some of the difficulties inherent in making transport property measurements at high temperatures are also listed

Simulation tests for temperature mixing in a core bottom model of the HTR-module

International Nuclear Information System (INIS)

Damm, G.; Wehrlein, R.

1992-01-01

Interatom and Siemens are developing a helium-cooled Modular High Temperature Reactor. Under nominal operating conditions temperature differences of up to 120deg C will occur in the 700deg C hot helium flow leaving the core. In addition, cold gas leakages into the hot gas header can produce even higher temperature differences in the coolant flow. At the outlet of the reactor only a very low temperature difference of maximum ± 15deg C is allowed in order to avoid damages at the heat exchanging components due to alternating thermal loads. Since it is not possible to calculate the complex flow behaviour, experimental investigations of the temperature mixing in the core bottom had to be carried out in order to guarantee the necessary reduction of temperature differences in the helium. The presented air simulation tests in a 1:2.9 scaled plexiglas model of the core bottom showed an extremely high mixing rate of the hot gas header and the hot gas duct of the reactor. The temperature mixing of the simulated coolant flow as well as the leakage flows was larger than 95%. Transfered to reactor conditions this means a temperature difference of only ± 3deg C for the main flow at a quite resonable pressure drop. For the cold gas leakages temperature differences in the hot gas up to 400deg C proved to be permissible. The results of the simulation experiments in the Aerodynamic Test Facility of Interatom permitted to design a shorter bottom reflector of the core. (orig.)

Red cell concentrate storage and transport temperature.

Science.gov (United States)

Hancock, V; Cardigan, R; Thomas, S

2011-10-01

This study investigated the current U.K. guidelines for storage and transport of red cell concentrates (RCC) in saline, adenine, glucose and mannitol (SAGM). The guidelines stipulate storage at 2-6 °C but allow exposure to between 1-10 °C core temperature in a single occurrence of less than 5 h and a surface temperature of 2-10 °C for no more than 12 h during transportation. Twenty RCC units in SAGM were selected on the day of blood collection (day 0) and in vitro quality was tested pre- and post-temperature deviation at 10 °C and up to day 42 of storage. Each group of 10 RCC units was incubated for either 12 h or for both 5 and 12 h. Haemolysis was below the 0·8% U.K. limit at day 42 in all units, although there was an unexpected trend towards lower haemolysis in packs incubated for 5 and 12 h rather than just 12 h alone. Supernatant potassium was significantly higher than reference data on day 35 (P levels of adenosine triphosphate and, 2,3-diphosphoglycerate to reference data from previous studies, throughout storage. These results suggest that exposure to 10 °C for 12 h or for 5 and 12 h did not adversely affect in vitro red cell quality for the remainder of the components shelf life. © 2011 The Authors. Transfusion Medicine © 2011 British Blood Transfusion Society.

Fission products distributions in Candu primary heat transport and Candu containment systems during a severe accident

International Nuclear Information System (INIS)

Constantin, Marin; Rizoiu, Andrei

2005-01-01

The paper is intended to analyse the distribution of the fission products (FPs) in CANDU Primary Heat Transport (PHT) and CANDU Containment Systems by using the ASTEC code (Accident Source Term Evaluation Code). The complexity of the data required by ASTEC and the complexity both of CANDU PHT and Containment System were strong motivations to begin with a simplified geometry in order to avoid the introducing of unmanageable errors at the level of input deck. Thus only 1/4 of the PHT circuit was simulated and a simplified FPs inventory, some simplifications in the feeders geometry and containment were used. The circuit consists of 95 horizontal fuel channels connected to 95 horizontal out-feeders, then through vertical feeders to the outlet-header (a big pipe that collects the water from feeders); the circuit continues from the outlet-header with a riser and then with the steam generator and a pump. After this pump, the circuit was broken; in this point the FPs are transferred to the containment. The containment model consists of 4 rooms connected between by 6 links. The data related to the nodes' definitions, temperatures and pressure conditions were chosen as possible as real data from CANDU NPP loss of coolant accident sequence. Temperature and pressure conditions in the time of the accident were calculated by the CATHENA code and the source term of FPs introduced into the PHT was estimated by the ORIGEN code. The FPs distribution in the nodes of the circuit and the FPs mass transfer per isotope and chemical species are obtained by using SOPHAEROS module of ASTEC code. The distributions into the containment are obtained by the CPA module of ASTEC code (thermalhydraulics calculations in the containment and FPs aerosol transport). The results consist of mass distributions in the nodes of the circuit and the transferred mass to the containment through the break for different species (FPs and chemical species) and mass distributions in the different parts and

Temperature-dependent charge injection and transport in pentacene thin-film transistors

International Nuclear Information System (INIS)

Kim, Dong Wook; Shin, Hyunji; Choi, Jong Sun; Park, Ji-Ho; Park, Jaehoon

2015-01-01

The electrical characteristics of p-channel pentacene thin-film transistors (TFTs) were analyzed at different operating temperatures ranging from 253 to 353 K. An improvement in the drain current and field-effect mobility of the pentacene TFTs is observed with increasing temperature. From the Arrhenius plots of field-effect mobility extracted at various temperatures, a lower activation energy of 99.34 meV was obtained when the device is operating in the saturation region. Such observation is ascribed to the thermally activated hole transport through the pentacene grain boundaries. On the other hand, it was found that the Au/pentacene contact significantly affects the TFTs electrical characteristics in the linear region, which resulted in a higher activation energy. The activation energy based on the linear field-effect mobility, which increased from 344.61 to 444.70 meV with decreasing temperature, implies the charge-injection-limited electrical behavior of pentacene TFTs at low temperatures. The thermally induced electrical characteristic variations in pentacene TFTs can thus be studied through the temperature dependence of the charge injection and transport processes. (paper)

Charge transport parameters of HBC at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Kirkpatrick, J. [Max Planck Institut fuer Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany); Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Marcon, V.; Kremer, K.; Andrienko, D. [Max Planck Institut fuer Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany); Nelson, J. [Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)

2008-05-15

We study the dependence on temperature of the charge transport parameters for hexabenzocoronene (HBC). Following from Marcus theory, two charge transport parameters will be calculated: the transfer integral and the difference in site energies. These parameters are strongly dependent on the orientation and position of molecules. Position and orientation of molecules are determined using molecular dynamics. Transfer integrals are calculated from a simplified INDO method. A technique to compute energetic disorder, that is the spread in site energies for the charge carriers, is developed. In the herringbone phase transfer integrals are higher, but so is energetic disorder. We consider three derivatives of HBC with different side chains, which lead to different phase behaviour and distributions of charge transport parameters. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Low-temperature ballistic transport in nanoscale epitaxial graphene cross junctions

OpenAIRE

Weingart, S.; Bock, C.; Kunze, U.; Speck, F.; Seyller, Th.; Ley, L.

2009-01-01

We report on the observation of inertial-ballistic transport in nanoscale cross junctions fabricated from epitaxial graphene grown on SiC(0001). Ballistic transport is indicated by a negative bend resistance of R12,43 ~ 170 ohm which is measured in a non-local, four-terminal configuration at 4.2 K and which vanishes as the temperature is increased above 80 K.

Low-temperature localization in the transport properties of self ...

Indian Academy of Sciences (India)

Transport properties; scattering mechanisms; low temperature localization. 1. Introduction ... Mn4+ appears in these compounds due to the La defi- ciency, leading ... microscopy (SEM) image in figure 1 shows the size and mor- phology of the ...

Room-temperature ballistic energy transport in molecules with repeating units

Energy Technology Data Exchange (ETDEWEB)

Rubtsova, Natalia I.; Nyby, Clara M.; Zhang, Hong; Zhang, Boyu; Zhou, Xiao; Jayawickramarajah, Janarthanan; Burin, Alexander L.; Rubtsov, Igor V., E-mail: irubtsov@tulane.edu [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States)

2015-06-07

In materials, energy can propagate by means of two limiting regimes: diffusive and ballistic. Ballistic energy transport can be fast and efficient and often occurs with a constant speed. Using two-dimensional infrared spectroscopy methods, we discovered ballistic energy transport via individual polyethylene chains with a remarkably high speed of 1440 m/s and the mean free path length of 14.6 Å in solution at room temperature. Whereas the transport via the chains occurs ballistically, the mechanism switches to diffusive with the effective transport speed of 130 m/s at the end-groups attached to the chains. A unifying model of the transport in molecules is presented with clear time separation and additivity among the transport along oligomeric fragments, which occurs ballistically, and the transport within the disordered fragments, occurring diffusively. The results open new avenues for making novel elements for molecular electronics, including ultrafast energy transporters, controlled chemical reactors, and sub-wavelength quantum nanoseparators.

Room-temperature ballistic energy transport in molecules with repeating units

International Nuclear Information System (INIS)

Rubtsova, Natalia I.; Nyby, Clara M.; Zhang, Hong; Zhang, Boyu; Zhou, Xiao; Jayawickramarajah, Janarthanan; Burin, Alexander L.; Rubtsov, Igor V.

2015-01-01

In materials, energy can propagate by means of two limiting regimes: diffusive and ballistic. Ballistic energy transport can be fast and efficient and often occurs with a constant speed. Using two-dimensional infrared spectroscopy methods, we discovered ballistic energy transport via individual polyethylene chains with a remarkably high speed of 1440 m/s and the mean free path length of 14.6 Å in solution at room temperature. Whereas the transport via the chains occurs ballistically, the mechanism switches to diffusive with the effective transport speed of 130 m/s at the end-groups attached to the chains. A unifying model of the transport in molecules is presented with clear time separation and additivity among the transport along oligomeric fragments, which occurs ballistically, and the transport within the disordered fragments, occurring diffusively. The results open new avenues for making novel elements for molecular electronics, including ultrafast energy transporters, controlled chemical reactors, and sub-wavelength quantum nanoseparators

Low temperature electrical transport in modified carbon nanotube fibres

International Nuclear Information System (INIS)

Lekawa-Raus, Agnieszka; Walczak, Kamil; Kozlowski, Gregory; Hopkins, Simon C.; Wozniak, Mariusz; Glowacki, Bartek A.; Koziol, Krzysztof

2015-01-01

Carbon nanotube fibres are a new class of materials highly promising for many electrical/electronic applications. The range of applications could be extended through the modification of their electrical transport properties by inclusions of foreign materials. However, the changes in electrical transport are often difficult to assess. Here, we propose that the analysis of resistance–temperature dependencies of modified fibres supported by a recently developed theoretical model may aid research in this area and accelerate real life applications of the fibres

X-rays diffraction characterization of corrosion products transported by secondary side of a CANDU NPP

International Nuclear Information System (INIS)

Dinu, A.; Tunaru, M.; Velciu, L.

2016-01-01

To verify the chemistry of secondary side of CANDU steam generators, Millipore filters are used to sampling from condensing extraction pump, from feed water header and blow down of steam generator. These filters retain the corrosion products as very fine particles and are used as samples in chemistry water control. X-Ray diffraction technique is the able to distinguish the different crystallographic compounds present in oxide films deposited on the Millipore filters and gives information referring to the nature of corrosion products transported in secondary side. The XRD analysis has identified the following substance in deposited layer: magnetite (Fe_3O_4), hematite (Fe_2O_3), and iron oxide hydroxide (FeOOH). By optical microscopy it was observed a brown-reddish background specific to hematite and iron oxide hydroxide, especially for filters extracted from condensing extraction pump. The black colour of crud present on filters extracted from feed water header and blow down of steam generator shows the presence of magnetite. (authors)

Development of high temperature molten salt transport technology for pyrometallurgical reprocessing

International Nuclear Information System (INIS)

Hijikata, Takatoshi; Koyama, Tadafumi

2009-01-01

Pyrometallurgical reprocessing technology is currently being focused in many countries for closing actinide fuel cycle because of its favorable economic potential and an intrinsic proliferation-resistant feature due to the inherent difficulty of extracting weapons-usable plutonium. The feasibility of pyrometallurgical reprocessing has been demonstrated through many laboratory scale experiments. Hence the development of the engineering technology necessary for pyrometallurgical reprocessing is a key issue for industrial realization. The development of high-temperature transport technologies for molten salt and liquid cadmium is crucial for pyrometallurgical processing; however, there have been very few transport studies on high-temperature fluids. In this study, a salt transport test rig was installed in an argon glove box with the aim of developing technologies for transporting molten salt at approximately 773 K. The gravitation transport of the molten salt at approximately 773 K could be well controlled at a velocity from 0.1 to 1.2 m/s by adjusting the valve. Consequently, the flow in the molten salt can be controlled from laminar flow to turbulent flow. It was demonstrated that; using a centrifugal pump, molten salt at approximately 773 K could be transported at a controlled rate from 2.5 to 8 dm 3 /min against a 1 m head. (author)

Transport properties of high-temperature superconductors: Surface vs bulk effect

International Nuclear Information System (INIS)

Burlachkov, L.; Koshelev, A.E.; Vinokur, V.M.

1996-01-01

We investigate surface-related transport properties of high-temperature superconductors. We find the mean vortex velocity under applied transport current determined by the activation energies for vortex penetration and exit through the Bean-Livingston barrier. We determine the current distribution between the surfaces of superconductor and the field and current dependencies of the transport activation energies. For a three-dimensional superconductor the transport activation energy, U s 3D , is found to decrease with the external field, H, and transport current, J, as U s 3D ∝H -1/2 and U s 3D ∝J -1/2 , respectively. In the quasi-two-dimensional compounds, U s 2D decays logarithmically with field and current. The interplay between the surface and the bulk contributions to the transport properties, such as current-voltage characteristics, is discussed. copyright 1996 The American Physical Society

System and method for air temperature control in an oxygen transport membrane based reactor

Science.gov (United States)

Kelly, Sean M

2016-09-27

A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

Relap5/Mod3.1 analysis of main steam header rupture in VVER- 440/213 NPP

Energy Technology Data Exchange (ETDEWEB)

Kral, P. [Nuclear Research Inst. Rez (Switzerland)

1995-12-31

The presentation is focused on two main topics. First the applied modelling of PGV-4 steam generator for RELAP5 code are described. The results of steady-state calculation under reference conditions are compared against measured data. The problem of longitudinal subdivision of SG tubes is analysed and evaluated. Secondly, a best-estimate analysis of main steam header (MSH) rupture accident in WWER-440/213 NPP is presented. The low reliability of initiation of ESFAS signal `MSH Rupture` leads in this accident to big loss of secondary coolant, full depressurization of main steam system, extremely fast cool-down of both secondary and primary system, opening of PRZ SV-bypass valve with later liquid outflow, potential reaching of secondary criticality by failure of HPIS. 7 refs.

Relap5/Mod3.1 analysis of main steam header rupture in VVER- 440/213 NPP

Energy Technology Data Exchange (ETDEWEB)

Kral, P [Nuclear Research Inst. Rez (Switzerland)

1996-12-31

The presentation is focused on two main topics. First the applied modelling of PGV-4 steam generator for RELAP5 code are described. The results of steady-state calculation under reference conditions are compared against measured data. The problem of longitudinal subdivision of SG tubes is analysed and evaluated. Secondly, a best-estimate analysis of main steam header (MSH) rupture accident in WWER-440/213 NPP is presented. The low reliability of initiation of ESFAS signal `MSH Rupture` leads in this accident to big loss of secondary coolant, full depressurization of main steam system, extremely fast cool-down of both secondary and primary system, opening of PRZ SV-bypass valve with later liquid outflow, potential reaching of secondary criticality by failure of HPIS. 7 refs.

Relap5/Mod3.1 analysis of main steam header rupture in VVER- 440/213 NPP

International Nuclear Information System (INIS)

Kral, P.

1995-01-01

The presentation is focused on two main topics. First the applied modelling of PGV-4 steam generator for RELAP5 code are described. The results of steady-state calculation under reference conditions are compared against measured data. The problem of longitudinal subdivision of SG tubes is analysed and evaluated. Secondly, a best-estimate analysis of main steam header (MSH) rupture accident in WWER-440/213 NPP is presented. The low reliability of initiation of ESFAS signal 'MSH Rupture' leads in this accident to big loss of secondary coolant, full depressurization of main steam system, extremely fast cool-down of both secondary and primary system, opening of PRZ SV-bypass valve with later liquid outflow, potential reaching of secondary criticality by failure of HPIS

Effect of temperature on the transport of solvents through PTMSP under ultra-high pressures

International Nuclear Information System (INIS)

Grekhov, A M; Belogorlov, A A; Eremin, Yu S; Pastukhova, E V; Yushkin, A A; Volkov, A V

2016-01-01

Despite a large number of studies, by now there is no any definitive explanation of the solvent transport mechanism in nanostructured polymer materials. Both convective and diffusive transport of solvents can be observed in these materials. The study of the solvents permeability at different temperatures and pressures allow the variation of the physical parameters and structure of the solvent-membrane interaction thus becoming the key factor in the understanding of the fundamental aspects of the selective transport process in nanostructured polymer membranes. The paper presents the study of ethanol, propanol and water transport through poly [1- (trimethylsilyl)-l-propine] (PTMSP) at pressures 50-150 atm and temperature up to 90°C. The study was done by the method of pressure dynamic decay. As the temperature rises, the permeability of ethanol and propanol through PTMSP is shown to increase in proportion to decreasing viscosity that denotes a convective type of transport. As for water, the permeability change is thermo-activated that is typical for a diffusive type of transport. This difference in the transport characteristics can be related to a change in the membrane structure and energetic characteristics of the solvent-polymer interaction. (paper)

Temperature dependence of transport coefficients of 'simple liquid ...

African Journals Online (AJOL)

... has been investigated. The study carried out at two densities, r* = 0.60 and r* = 0.95. Result shows erratic variations of the shear viscosity in the two lattices structures. KeyWords: Temperature effect, face centred, simple cubic, transport properties, simple liquid. [Global Jnl Pure & Appl. Sci. Vol.9(3) 2003: 403-406] ...

All-Cause and Cause-Specific Risk of Emergency Transport Attributable to Temperature: A Nationwide Study.

Science.gov (United States)

Onozuka, Daisuke; Hagihara, Akihito

2015-12-01

Although several studies have estimated the associations between mortality or morbidity and extreme temperatures in terms of relative risk, few studies have investigated the risk of emergency transport attributable to the whole temperature range nationwide.We acquired data on daily emergency ambulance dispatches in all 47 prefectures of Japan from 2007 to 2010. We examined the relationship between emergency transport and temperature for each prefecture using a Poisson regression model in a distributed lag nonlinear model with adjustment for time trends. A random-effect multivariate meta-analysis was then applied to pool the estimates at the national level. Attributable morbidity was calculated for high and low temperatures, which were defined as those above or below the optimum temperature (ie, the minimum morbidity temperature) and for moderate and also extreme temperatures, which were defined using cutoffs at the 2.5th and 97.5th temperature percentiles.A total of 15,868,086 cases of emergency transport met the inclusion criteria. The emergency transport was attributable to nonoptimal temperature. The median minimum morbidity percentile was in the 79th percentile for all causes, the 96th percentile for cardiovascular disease, and the 92th percentile for respiratory disease. The fraction attributable to low temperature was 6.94% (95% eCI: 5.93-7.70) for all causes, 17.93% (95% eCI: 16.10-19.25) for cardiovascular disease, and 12.19% (95% eCI: 9.90-13.66) for respiratory disease, whereas the fraction attributable to high temperature was small (all causes = 1.01%, 95% eCI: 0.90-1.11; cardiovascular disease = 0.10%, 95% eCI: 0.04-0.14; respiratory disease = 0.29%, 95% eCI: 0.07-0.50). The all-cause morbidity risk that was attributable to temperature was related to moderate cold, with an overall estimate of 6.41% (95% eCI: 5.47-7.20). Extreme temperatures were responsible for a small fraction, which corresponded to 0.57% (95% eCI: 0.50-0.62) for extreme

Low-temperature transport in ultra-thin tungsten films

Energy Technology Data Exchange (ETDEWEB)

Chiatti, Olivio [Neue Materialien, Institut fuer Physik, Humboldt-Univ. Berlin (Germany); London Centre for Nanotechnology, University College London (United Kingdom); Nash, Christopher; Warburton, Paul [London Centre for Nanotechnology, University College London (United Kingdom)

2012-07-01

Tungsten-containing films, fabricated by focused-ion-beam-induced chemical vapour deposition, are known to have an enhanced superconducting transition temperature compared to bulk tungsten, and have been investigated previously for film thickness down to 25 nm. In this work, by using ion-beam doses below 50 pC/{mu}m{sup 2} on a substrate of amorphous silicon, we have grown continuous films with thickness below 20 nm. The electron transport properties were investigated at temperatures down to 350 mK and in magnetic fields up to 3 T, parallel and perpendicular to the films. The films in this work are closer to the limit of two-dimensional systems and are superconducting at low temperatures. Magnetoresistance measurements yield upper critical fields of the order of 1 T, and the resulting coherence length is smaller than the film thickness.

Universal Broadening of the Light Cone in Low-Temperature Transport

Science.gov (United States)

Bertini, Bruno; Piroli, Lorenzo; Calabrese, Pasquale

2018-04-01

We consider the low-temperature transport properties of critical one-dimensional systems that can be described, at equilibrium, by a Luttinger liquid. We focus on the prototypical setting where two semi-infinite chains are prepared in two thermal states at small but different temperatures and suddenly joined together. At large distances x and times t , conformal field theory characterizes the energy transport in terms of a single light cone spreading at the sound velocity v . Energy density and current take different constant values inside the light cone, on its left, and on its right, resulting in a three-step form of the corresponding profiles as a function of ζ =x /t . Here, using a nonlinear Luttinger liquid description, we show that for generic observables this picture is spoiled as soon as a nonlinearity in the spectrum is present. In correspondence of the transition points x /t =±v , a novel universal region emerges at infinite times, whose width is proportional to the temperatures on the two sides. In this region, expectation values have a different temperature dependence and show smooth peaks as a function of ζ . We explicitly compute the universal function describing such peaks. In the specific case of interacting integrable models, our predictions are analytically recovered by the generalized hydrodynamic approach.

Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

International Nuclear Information System (INIS)

Tamura, N.; Inagaki, S.; Tokuzawa, T.

2006-10-01

Edge cooling experiments with a tracer-encapsulated solid pellet in the Large Helical Device (LHD) show a significant rise of core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport is dominated. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay of the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase in collisionality in the core plasma and the decrease in electron temperature gradient scale length in the outer region of the plasma. (author)

Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

International Nuclear Information System (INIS)

Tamura, N.; Inagaki, S.; Tanaka, K.; Michael, C.; Tokuzawa, T.; Shimozuma, T.; Kubo, S.; Sakamoto, R.; Ida, K.; Itoh, K.; Kalinina, D.; Sudo, S.; Nagayama, Y.; Kawahata, K.; Komori, A.

2007-01-01

Edge cooling experiments with a tracer-encapsulated solid pellet in the large helical device (LHD) show a significant rise in core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport dominates. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay in the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase both in the collisionality in the core plasma and the electron temperature gradient scale length in the outer region of the plasma

A reduced model for ion temperature gradient turbulent transport in helical plasmas

International Nuclear Information System (INIS)

Nunami, M.; Watanabe, T.-H.; Sugama, H.

2013-07-01

A novel reduced model for ion temperature gradient (ITG) turbulent transport in helical plasmas is presented. The model enables one to predict nonlinear gyrokinetic simulation results from linear gyrokinetic analyses. It is shown from nonlinear gyrokinetic simulations of the ITG turbulence in helical plasmas that the transport coefficient can be expressed as a function of the turbulent fluctuation level and the averaged zonal flow amplitude. Then, the reduced model for the turbulent ion heat diffusivity is derived by representing the nonlinear turbulent fluctuations and zonal flow amplitude in terms of the linear growth rate of the ITG instability and the linear response of the zonal flow potentials. It is confirmed that the reduced transport model results are in good agreement with those from nonlinear gyrokinetic simulations for high ion temperature plasmas in the Large Helical Device. (author)

Peak cladding temperature in a spent fuel storage or transportation cask

International Nuclear Information System (INIS)

Li, J.; Murakami, H.; Liu, Y.; Gomez, P.E.A.; Gudipati, M.; Greiner, M.

2007-01-01

From reactor discharge to eventual disposition, spent nuclear fuel assemblies from a commercial light water reactor are typically exposed to a variety of environments under which the peak cladding temperature (PCT) is an important parameter that can affect the characteristics and behavior of the cladding and, thus, the functions of the spent fuel during storage, transportation, and disposal. Three models have been identified to calculate the peak cladding temperature of spent fuel assemblies in a storage or transportation cask: a coupled effective thermal conductivity and edge conductance model developed by Manteufel and Todreas, an effective thermal conductivity model developed by Bahney and Lotz, and a computational fluid dynamics model. These models were used to estimate the PCT for spent fuel assemblies for light water reactors under helium, nitrogen, and vacuum environments with varying decay heat loads and temperature boundary conditions. The results show that the vacuum environment is more challening than the other gas environments in that the PCT limit is exceeded at a lower boundary temperature for a given decay heat load of the spent fuel assembly. This paper will highlight the PCT calculations, including a comparison of the PCTs obtained by different models.

Opposite temperature effect on transport activity of KCC2/KCC4 and N(K)CCs in HEK-293 cells.

Science.gov (United States)

Hartmann, Anna-Maria; Nothwang, Hans Gerd

2011-12-09

Cation chloride cotransporters play essential roles in many physiological processes such as volume regulation, transepithelial salt transport and setting the intracellular chloride concentration in neurons. They consist mainly of the inward transporters NCC, NKCC1, and NKCC2, and the outward transporters KCC1 to KCC4. To gain insight into regulatory and structure-function relationships, precise determination of their activity is required. Frequently, these analyses are performed in HEK-293 cells. Recently the activity of the inward transporters NKCC1 and NCC was shown to increase with temperature in these cells. However, the temperature effect on KCCs remains largely unknown. Here, we determined the temperature effect on KCC2 and KCC4 transport activity in HEK-293 cells. Both transporters demonstrated significantly higher transport activity (2.5 fold for KCC2 and 3.3 fold for KCC4) after pre-incubation at room temperature compared to 37°C. These data identify a reciprocal temperature dependence of cation chloride inward and outward cotransporters in HEK-293 cells. Thus, lower temperature should be used for functional characterization of KCC2 and KCC4 and higher temperatures for N(K)CCs in heterologous mammalian expression systems. Furthermore, if this reciprocal effect also applies to neurons, the action of inhibitory neurotransmitters might be more affected by changes in temperature than previously thought.

Growth and Low Temperature Transport Measurements of Pure and Doped Bismuth Selenide

DEFF Research Database (Denmark)

Mlack, Jerome Thomas

Se3, which is a strong spin orbit material and a topological insulator. I describe a synthesis technique and low-temperature transport measurements of nanostructures of Bi2Se3, that when annealed with palladium show evidence of superconductivity. The growth method is a catalyst-free atmospheric...... with palladium via annealing, the transport properties of the samples can be altered to exhibit superconductivity. Thin films of palladium are deposited on prefabricated Bi2Se3 nanodevices and annealed at temperatures in excess of 100 Celsius. We find that Bi2Se3 absorbs Pd under these conditions...... pressure vapor-solid growth. The growth method yields a variety of nanostructures, and materials analysis shows ordered structures of bismuth selenide in all cases. Low-temperature measurements of as-grown nanostructures indicate tunable carrier density in all samples. By doping the nanostructures...

Characteristics of the oil transport network in the South of Mexico

Science.gov (United States)

Juárez, R.; Fernández, I. Y.; Guzmán, L.

2017-01-01

We present a study of some organizational properties of the oil transport network of the Mexican oil company (PEMEX) in a region of the State of Tabasco. Particularly, the generalized centrality and the distribution of connectivities are calculated in order to evaluate some aspects of the structure of the network. We find that the connectivities (k) are characterized by a degree distribution which follows a power-law function of the form, P(k)~k -λ, with λ = 2.6. Moreover, our procedure permits to evalute the importance of lines (ducts) and nodes, which can be wells, production headers, separation batteries and petrochemical complexes.

Self-heating, gamma heating and heat loss effects on resistance temperature detector (RTD) accuracy

International Nuclear Information System (INIS)

Qian, T.; Hinds, H.W.; Tonner, P.

1997-01-01

Resistance temperature detectors (RTDs) are extensively used in CANDU nuclear power stations for measuring various process and equipment temperatures. Accuracy of measurement is an important performance parameter of RTDs and has great impact on the thermal power efficiency and safety of the plant. There are a number of factors that contribute to some extent to RTD measurement error. Self-heating, gamma heating and the heat-loss throughout conduction of the thermowell are three of these factors. The degree to which these three affect accuracy of RTDs used for the measurement of reactor inlet header temperature (RIHT) has been analyzed and is presented in this paper. (author)

A Document-Based EHR System That Controls the Disclosure of Clinical Documents Using an Access Control List File Based on the HL7 CDA Header.

Science.gov (United States)

Takeda, Toshihiro; Ueda, Kanayo; Nakagawa, Akito; Manabe, Shirou; Okada, Katsuki; Mihara, Naoki; Matsumura, Yasushi

2017-01-01

Electronic health record (EHR) systems are necessary for the sharing of medical information between care delivery organizations (CDOs). We developed a document-based EHR system in which all of the PDF documents that are stored in our electronic medical record system can be disclosed to selected target CDOs. An access control list (ACL) file was designed based on the HL7 CDA header to manage the information that is disclosed.

Electron Temperature Fluctuation Measurements and Transport Model Validation at Alcator C-Mod

Energy Technology Data Exchange (ETDEWEB)

White, Anne [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2017-06-22

for studying core turbulence are needed in order to assess the accuracy of gyrokinetic models for turbulent-driven particle, heat and momentum transport. New core turbulence diagnostics at the world-class tokamaks Alcator C-Mod at MIT and ASDEX Upgrade at the Max Planck Institute for Plasma Physics have been designed, developed, and operated over the course of this project. These new instruments are capable of measuring electron temperature fluctuations and the phase angle between density and temperature fluctuations locally and quantitatively. These new data sets from Alcator C-Mod and ASDEX Upgrade are being used to fill key gaps in our understanding of turbulent transport in tokamaks. In particular, this project has results in new results on the topics of the Transport Shortfall, the role of ETG turbulence in tokamak plasmas, profile stiffness, the LOC/SOC transition, and intrinsic rotation reversals. These data are used in a rigorous process of “Transport model validation”, and this group is a world-leader on using turbulence models to design new hardware and new experiments at tokamaks. A correlation electron cyclotron emission (CECE) diagnostic is an instrument used to measure micro-scale fluctuations (mm-scale, compared to the machine size of meters) of electron temperature in magnetically confined fusion plasmas, such as those in tokamaks and stellarators. These micro-scale fluctuations are associated with drift-wave type turbulence, which leads to enhanced cooling and mixing of particles in fusion plasmas and limits achieving the required temperatures and densities for self-sustained fusion reactions. A CECE system can also be coupled with a reflectometer system that measured micro-scale density fluctuations, and from these simultaneous measurements, one can extract the phase between the density (n) and temperature (T) fluctuations, creating an nT phase diagnostic. Measurements of the fluctuations and the phase angle between them are extremely useful for

Analog performance of vertical nanowire TFETs as a function of temperature and transport mechanism

Science.gov (United States)

Martino, Marcio Dalla Valle; Neves, Felipe; Ghedini Der Agopian, Paula; Martino, João Antonio; Vandooren, Anne; Rooyackers, Rita; Simoen, Eddy; Thean, Aaron; Claeys, Cor

2015-10-01

The goal of this work is to study the analog performance of tunnel field effect transistors (TFETs) and its susceptibility to temperature variation and to different dominant transport mechanisms. The experimental input characteristic of nanowire TFETs with different source compositions (100% Si and Si1-xGex) has been presented, leading to the extraction of the Activation Energy for each bias condition. These first results have been connected to the prevailing transport mechanism for each configuration, namely band-to-band tunneling (BTBT) or trap assisted tunneling (TAT). Afterward, this work analyzes the analog behavior, with the intrinsic voltage gain calculated in terms of Early voltage, transistor efficiency, transconductance and output conductance. Comparing the results for devices with different source compositions, it is interesting to note how the analog trends vary depending on the source characteristics and the prevailing transport mechanisms. This behavior results in a different suitability analysis depending on the working temperature. In other words, devices with full-Silicon source and non-abrupt junction profile present the worst intrinsic voltage gain at room temperature, but the best results for high temperatures. This was possible since, among the 4 studied devices, this configuration was the only one with a positive intrinsic voltage gain dependence on the temperature variation.

The effect of temperature on the photosynthesis and 14C-photosynthetic products transportation and distribution in cucumber

International Nuclear Information System (INIS)

Shi Yuelin; Sun Yiezhi; Xu Guimin; Cai Qiyun

1991-01-01

The optimum temperature of photosynthesis tended to become higher following the growth of cucumber. The optimum temperature was 30 deg C at the early growth stage and 35 deg C at the late growth stage. Stomatal resistance decreased and transpiration rate increased with increasing of the temperature. Most of the 14 C-photosynthetic products in leaves were transported out at 30 deg C during the day. After one night, more photosynthetic products were transported out under higher temperature. From the early to the middle growth stage, most of the 14 C-photosynthetic products were transported to fruits at 30 deg C. But caulis, leaves and apical point obtained most of the photosynthetic products at 35 deg C. At the late growth stage, most of the 14 C-photosynthetic products were transported to fruits at 35 deg c. At 25 deg C, caulis and leaves got more 14 C-photosynthetic products

Instability and transport driven by an electron temperature gradient close to critical

International Nuclear Information System (INIS)

Dong, J.Q.; Jian, G.D.; Wang, A.K.; Sanuki, H.; Itoh, K.

2003-01-01

Electron temperature gradient (ETG) driven instability in toroidal plasmas is studied with gyrokinetic theory. The full electron kinetics is considered. The upgraded numerical scheme for solving the integral eigenvalue equations allows the study of both growing and damping modes, and thus direct calculation of critical gradient. Algebraic formulas for the critical gradient with respect to ratio of electron temperature over ion temperature and to toroidicity are given. An estimation for turbulence induced transport is presented. (author)

Transport of temperature and humidity variance and covariance in the marine surface layer

DEFF Research Database (Denmark)

Sempreviva, A.M.; Højstrup, J.

1998-01-01

In this paper we address the budget of potential temperature T and moisture mixing ratio q variances as well as the q - T covariance budget. We focus on the vertical transport and study the quantities contained in these terms. Estimates of transport terms are rare and to the best of our knowledge...

Room-Temperature Quantum Ballistic Transport in Monolithic Ultrascaled Al-Ge-Al Nanowire Heterostructures.

Science.gov (United States)

Sistani, Masiar; Staudinger, Philipp; Greil, Johannes; Holzbauer, Martin; Detz, Hermann; Bertagnolli, Emmerich; Lugstein, Alois

2017-08-09

Conductance quantization at room temperature is a key requirement for the utilizing of ballistic transport for, e.g., high-performance, low-power dissipating transistors operating at the upper limit of "on"-state conductance or multivalued logic gates. So far, studying conductance quantization has been restricted to high-mobility materials at ultralow temperatures and requires sophisticated nanostructure formation techniques and precise lithography for contact formation. Utilizing a thermally induced exchange reaction between single-crystalline Ge nanowires and Al pads, we achieved monolithic Al-Ge-Al NW heterostructures with ultrasmall Ge segments contacted by self-aligned quasi one-dimensional crystalline Al leads. By integration in electrostatically modulated back-gated field-effect transistors, we demonstrate the first experimental observation of room temperature quantum ballistic transport in Ge, favorable for integration in complementary metal-oxide-semiconductor platform technology.

Two-temperature thermodynamic and transport properties of SF6–Cu plasmas

International Nuclear Information System (INIS)

Wu, Yi; Chen, Zhexin; Yang, Fei; Rong, Mingzhe; Sun, Hao; Cressault, Yann; Murphy, Anthony B; Guo, Anxiang; Liu, Zirui

2015-01-01

SF 6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF 6 –Cu plasmas are frequently formed, particularly in high-voltage circuit breaker arcs and fault current arcs, due to erosion of the Cu components. In this paper, calculated values of the thermodynamic and transport properties of plasmas in SF 6 –Cu mixtures are presented for both thermal equilibrium and non-equilibrium conditions. The composition is determined by the two-temperature Saha equation and Guldberg–Waage equation in the form derived by van de Sanden. The composition and the thermodynamic properties are evaluated through a classical statistical mechanics approach. For the transport coefficients, the simplified Chapman–Enskog method developed by Devoto, which decouples the electrons and heavy species, has been applied using the most recent collision integrals. The thermodynamic and transport properties are calculated for different electron temperatures (300–40 000 K), ratios of electron to heavy-species temperature (1–10), pressures (0.1–10 atm) and copper molar proportions (0–50%). It is found that deviations from thermal equilibrium strongly affect the thermodynamic and transport properties of the SF 6 –Cu plasmas. Further, the presence of copper has different effects on some of the properties for plasmas in and out of thermal equilibrium. The main reason for these changes is that dissociation reactions are delayed for non-thermal equilibrium plasmas, which in turn influences the ionization reactions that occur. (paper)

Low-temperature spin transport in a S = 1 one-dimensional antiferromagnet

International Nuclear Information System (INIS)

Pires, A S T; Lima, L S

2009-01-01

We study spin transport in the insulating antiferromagnet with S = 1 in one dimension. The spin conductivity is calculated, at zero temperature, using a modified spin wave theory and the Kubo formalism, within the ladder approximation. Two-magnon processes provide the dominant contribution to the spin conductivity. At finite temperature, free magnons are activated, and turn the system into a perfect spin conductor, i.e., the spin conductivity has a Drude form with infinite scattering time.

Outward transport of high-temperature materials around the midplane of the solar nebula.

Science.gov (United States)

Ciesla, Fred J

2007-10-26

The Stardust samples collected from Comet 81P/Wild 2 indicate that large-scale mixing occurred in the solar nebula, carrying materials from the hot inner regions to cooler environments far from the Sun. Similar transport has been inferred from telescopic observations of protoplanetary disks around young stars. Models for protoplanetary disks, however, have difficulty explaining the observed levels of transport. Here I report the results of a new two-dimensional model that shows that outward transport of high-temperature materials in protoplanetary disks is a natural outcome of disk formation and evolution. This outward transport occurs around the midplane of the disk.

Analysis of flow fields, temperatures and ruthenium transport in the test facility

International Nuclear Information System (INIS)

Kaerkelae, T.; Pyykoenen, J.; Auvinen, A.; Jokiniemi, J.

2008-03-01

Ruthenium transport experiments were conducted at VTT during years 2002- 2006. Experiments gave information about ruthenium behaviour in air ingress accident conditions. This study complements those experiments with an analysis of the flows and thermal fields in the test system. Temperature profiles were measured at the walls of the experimental facility. Computational fluid dynamics (CFD) simulations used the measured profiles and provided predictions of flows and temperatures inside the furnace. Ruthenium transport was also modelled with CFD. Thermal characterisation of the reactor demonstrated that buoyancy has a significant role during the cooling after the furnace. A hypothesis of the dominant role of RuO2 and RuO3 condensation on reactor walls gave simulation results that are in accordance with radiotracer measurements of deposition in experiments conducted with furnace at 1500K. Actually, RuO3 does not condensate, but it thermal decomposes to RuO2. This does not seem to have effect on result. Particle formation around the furnace exit could be detected from the comparison of modelling results with the measured profiles. In several other experiments ruthenium behaviour is dominated by other issues. These are related to the complex ruthenium chemistry that includes various surface reactions. Thermal equilibrium indicates significant gaseous RuO4 concentration around 1300 K. It seems that seed particles decreased the catalytic decomposition activity of RuO4 to RuO2 around this temperature pushing the gas concentration towards the equilibrium, and further give rise to gaseous RuO4 transport to low temperatures. At higher temperature increasing mass flow rate of RuO2 particles is likely to catalyse (decomposition) reaction of RuO4 to RuO2. (au)

Analysis of flow fields, temperatures and ruthenium transport in the test facility

Energy Technology Data Exchange (ETDEWEB)

Kaerkelae, T.; Pyykoenen, J.; Auvinen, A.; Jokiniemi, J. [Technical Research Centre of Finland VTT (Finland)

2008-03-15

Ruthenium transport experiments were conducted at VTT during years 2002- 2006. Experiments gave information about ruthenium behaviour in air ingress accident conditions. This study complements those experiments with an analysis of the flows and thermal fields in the test system. Temperature profiles were measured at the walls of the experimental facility. Computational fluid dynamics (CFD) simulations used the measured profiles and provided predictions of flows and temperatures inside the furnace. Ruthenium transport was also modelled with CFD. Thermal characterisation of the reactor demonstrated that buoyancy has a significant role during the cooling after the furnace. A hypothesis of the dominant role of RuO2 and RuO3 condensation on reactor walls gave simulation results that are in accordance with radiotracer measurements of deposition in experiments conducted with furnace at 1500K. Actually, RuO3 does not condensate, but it thermal decomposes to RuO2. This does not seem to have effect on result. Particle formation around the furnace exit could be detected from the comparison of modelling results with the measured profiles. In several other experiments ruthenium behaviour is dominated by other issues. These are related to the complex ruthenium chemistry that includes various surface reactions. Thermal equilibrium indicates significant gaseous RuO4 concentration around 1300 K. It seems that seed particles decreased the catalytic decomposition activity of RuO4 to RuO2 around this temperature pushing the gas concentration towards the equilibrium, and further give rise to gaseous RuO4 transport to low temperatures. At higher temperature increasing mass flow rate of RuO2 particles is likely to catalyse (decomposition) reaction of RuO4 to RuO2. (au)

Considerations from the viewpoint of neoclassical transport towards higher ion temperature heliotron plasmas

International Nuclear Information System (INIS)

Yokoyama, M.; Matsuoka, S.; Funaba, H.; Ida, K.; Nagaoka, K.; Yoshinuma, M.; Takeiri, Y.; Kaneko, O.

2010-01-01

The neoclassical (NC) transport analyses have been performed to elucidate the plausible approaches towards higher ion-temperature heliotron plasmas. Avoidance of the ripple transport is the key issue, for which the neoclassical ambipolar radial electric field (E r ) can be utilized. The ion-root scenario and the electron-root scenario are expected to be effective according to the experimental situation (especially, the temperature ratio between ions and electrons). The impact of the ion mass on the neoclassical ambipolar E r is also investigated to reveal the easier realization of electron-root E r in heavier ion plasmas. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Temperature dependent transport of two dimensional electrons in the integral quantum Hall regime

International Nuclear Information System (INIS)

Wi, H.P.

1986-01-01

This thesis is concerned with the temperature dependent electronic transport properties of a two dimensional electron gas subject to background potential fluctuations and a perpendicular magnetic field. The author carried out an extensive temperature dependent study of the transport coefficients, in the region of an integral quantum plateau, in an In/sub x/Ga/sub 1-x/As/InP heterostructure for 4.2K 10 cm -2 meV -1 ) even at the middle between two Landau levels, which is unexpected from model calculations based on short ranged randomness. In addition, the different T dependent behavior of rho/sub xx/ between the states in the tails and those near the center of a Landau level, indicates the existence of different electron states in a Landau level. Additionally, the author reports T-dependent transport measurements in the transition region between two quantum plateaus in several different materials

Transport coefficients in high-temperature ionized air flows with electronic excitation

Science.gov (United States)

Istomin, V. A.; Oblapenko, G. P.

2018-01-01

Transport coefficients are studied in high-temperature ionized air mixtures using the modified Chapman-Enskog method. The 11-component mixture N2/N2+/N /N+/O2/O2+/O /O+/N O /N O+/e- , taking into account the rotational and vibrational degrees of freedom of molecules and electronic degrees of freedom of both atomic and molecular species, is considered. Using the PAINeT software package, developed by the authors of the paper, in wide temperature range calculations of the thermal conductivity, thermal diffusion, diffusion, and shear viscosity coefficients for an equilibrium ionized air mixture and non-equilibrium flow conditions for mixture compositions, characteristic of those in shock tube experiments and re-entry conditions, are performed. For the equilibrium air case, the computed transport coefficients are compared to those obtained using simplified kinetic theory algorithms. It is shown that neglecting electronic excitation leads to a significant underestimation of the thermal conductivity coefficient at temperatures higher than 25 000 K. For non-equilibrium test cases, it is shown that the thermal diffusion coefficients of neutral species and the self-diffusion coefficients of all species are strongly affected by the mixture composition, while the thermal conductivity coefficient is most strongly influenced by the degree of ionization of the flow. Neglecting electronic excitation causes noticeable underestimation of the thermal conductivity coefficient at temperatures higher than 20 000 K.

Characterisation of temperature gradient driven turbulence and transport

International Nuclear Information System (INIS)

Ottaviani, M.A.

2002-01-01

We report on extensive numerical studies aimed at characterising various aspects of temperature gradient driven turbulence. We specifically discuss results from 3D fluid models of ETG and of ITG turbulence, and results from a 2D+2D gyrokinetic model of trapped ion turbulence. Global transport exhibits gyro-Bohm scaling in both the ETG and the ITG model. The conductivity of the ETG model decreases weakly with beta. The heat transport is due to the EXB advection, the effect of the magnetic flutter is negligible. However the transport level is much lower than experimentally observed. In both 3D models the correlation lengths scale with the gyroradius, but they are typically a factor 10 larger. Vortices are elongated but their aspect ratio is independent of the gyroradius. Their radial size is limited by LD. The trapped ion model gives larger vortices due to the absence of LD from passing ions. Avalanches are observed in all the models, the weakest occurring in the ITG system. Their range increases with gyroradius, but more weakly than linearly. Finally, ZFs can limit the range of the avalanches, which explains why avalanches are weaker in the ITG model which is more sensitive to ZFs. (author)

Temperature fields occurring in dielectric capillaries for the transport of of ion beams

International Nuclear Information System (INIS)

Urbanovich, A.I.

2012-01-01

This paper presents the results of computing the temperature fields occurring in dielectric capillaries of glass for the transport of accelerated charged particles. It is shown that on the transport of ion beams with a power of several watts the capillary is heated intensively, whereas heat stresses may approach the lower bound associated with a real strength of glass. (authors)

Two-Dimensional Spatial Imaging of Charge Transport in Germanium Crystals at Cryogenic Temperatures

Energy Technology Data Exchange (ETDEWEB)

Moffatt, Robert [Stanford Univ., CA (United States)

2016-03-01

In this dissertation, I describe a novel apparatus for studying the transport of charge in semiconductors at cryogenic temperatures. The motivation to conduct this experiment originated from an asymmetry observed between the behavior of electrons and holes in the germanium detector crystals used by the Cryogenic Dark Matter Search (CDMS). This asymmetry is a consequence of the anisotropic propagation of electrons in germanium at cryogenic temperatures. To better model our detectors, we incorporated this effect into our Monte Carlo simulations of charge transport. The purpose of the experiment described in this dissertation is to test those models in detail. Our measurements have allowed us to discover a shortcoming in our most recent Monte Carlo simulations of electrons in germanium. This discovery would not have been possible without the measurement of the full, two-dimensional charge distribution, which our experimental apparatus has allowed for the first time at cryogenic temperatures.

CCP Sensitivity Analysis by Variation of Thermal-Hydraulic Parameters of Wolsong-3, 4

Energy Technology Data Exchange (ETDEWEB)

You, Sung Chang [KHNP, Daejeon (Korea, Republic of)

2016-10-15

The PHWRs are tendency that ROPT(Regional Overpower Protection Trip) setpoint is decreased with reduction of CCP(Critical Channel Power) due to aging effects. For this reason, Wolsong unit 3 and 4 has been operated less than 100% power due to the result of ROPT setpoint evaluation. Typically CCP for ROPT evaluation is derived at 100% PHTS(Primary Heat Transport System) boundary conditions - inlet header temperature, header to header different pressure and outlet header pressure. Therefore boundary conditions at 100% power were estimated to calculate the thermal-hydraulic model at 100% power condition. Actually thermal-hydraulic boundary condition data for Wolsong-3 and 4 cannot be taken at 100% power condition at aged reactor condition. Therefore, to create a single-phase thermal-hydraulic model with 80% data, the validity of the model was confirmed at 93.8%(W3), 94.2%(W4, in the two-phase). And thermal-hydraulic boundary conditions at 100% power were calculated to use this model. For this reason, the sensitivities by varying thermal-hydraulic parameters for CCP calculation were evaluated for Wolsong unit 3 and 4. For confirming the uncertainties by variation PHTS model, sensitivity calculations were performed by varying of pressure tube roughness, orifice degradation factor and SG fouling factor, etc. In conclusion, sensitivity calculation results were very similar and the linearity was constant.

Universal linear-temperature resistivity: possible quantum diffusion transport in strongly correlated superconductors.

Science.gov (United States)

Hu, Tao; Liu, Yinshang; Xiao, Hong; Mu, Gang; Yang, Yi-Feng

2017-08-25

The strongly correlated electron fluids in high temperature cuprate superconductors demonstrate an anomalous linear temperature (T) dependent resistivity behavior, which persists to a wide temperature range without exhibiting saturation. As cooling down, those electron fluids lose the resistivity and condense into the superfluid. However, the origin of the linear-T resistivity behavior and its relationship to the strongly correlated superconductivity remain a mystery. Here we report a universal relation [Formula: see text], which bridges the slope of the linear-T-dependent resistivity (dρ/dT) to the London penetration depth λ L at zero temperature among cuprate superconductor Bi 2 Sr 2 CaCu 2 O 8+δ and heavy fermion superconductors CeCoIn 5 , where μ 0 is vacuum permeability, k B is the Boltzmann constant and ħ is the reduced Planck constant. We extend this scaling relation to different systems and found that it holds for other cuprate, pnictide and heavy fermion superconductors as well, regardless of the significant differences in the strength of electronic correlations, transport directions, and doping levels. Our analysis suggests that the scaling relation in strongly correlated superconductors could be described as a hydrodynamic diffusive transport, with the diffusion coefficient (D) approaching the quantum limit D ~ ħ/m*, where m* is the quasi-particle effective mass.

Two-temperature transport coefficients of SF6–N2 plasma

International Nuclear Information System (INIS)

Yang, Fei; Chen, Zhexin; Wu, Yi; Rong, Mingzhe; Wang, Chunlin; Guo, Anxiang; Liu, Zirui

2015-01-01

Sulfur hexafluoride (SF 6 ) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF 6 is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF 6 –N 2 mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF 6 . This paper is devoted to the calculation of and transport coefficients of SF 6 –N 2 mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N 2 mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF 6 –N 2 plasma, especially before the plasma is fully ionized. The different influence of N 2 on properties for SF 6 –N 2 plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF 6 –N 2 plasmas

Transportation of perishable and refrigerated foods in mylar foil bags and insulated containers: a time-temperature study.

Science.gov (United States)

Li, Yanyan; Schrade, John P; Su, Haiyan; Specchio, John J

2014-08-01

Data are lacking on the temperature changes of food during transport without the use of refrigerated trucks. The purpose of this study was to evaluate the ability of several insulated and noninsulated containers with or without frozen gel packs to keep perishable and refrigerated foods within the temperature safe zone in relationship to duration of transport. The study was designed to duplicate the practices exhibited by customers purchasing perishable food products from a cash-and-carry business. Approximately 40 perishable food items were evaluated. Four types of containers were tested: a mylar foil bag, a commercial insulated bag, a generic insulated bag, and a commercial insulated blanket. Mixed foods were placed into these containers with or without frozen gel packs, transported in unrefrigerated vehicles, and monitored for 4 h for temperature changes. Two environmental temperatures, room temperature of 21.1°C and a stress temperature of 37.8°C, were evaluated. The internal temperature and surface temperature of the food products in these containers increased slowly but remained well below the U.S. Food and Drug Administration Food Code requirements. The various containers were similar in their ability to retain coolness. The presence of frozen gel packs dramatically enhanced the cold-holding capacity of the containers. The temperature of foods increased more rapidly when stressed in a heated environment. The containers tested used with the frozen gel packs can keep the surface and internal temperatures of various perishable foods (starting at 4.4°C or less) within the Food Code recommendation of under 21.1°C for 4 h. Cash-and-carry businesses should strongly encourage their retail customers to utilize these containers with frozen gel packs to safely transport perishable foods.

Electrical transport in La1−xCaxMnO3 thin films at low temperatures

Indian Academy of Sciences (India)

quadratic temperature dependence at low temperatures is attributed to the collapse of the minority spin band. The two-magnon and electron–phonon processes contribute to scattering of carriers in the temperature range above 120 K. Keywords. La1−x Cax MnO3 thin films; electrical transport; low temperature resistivity; ...

Towards a Room-Temperature Spin Quantum Bus in Diamond via Electron Photoionization, Transport, and Capture

Directory of Open Access Journals (Sweden)

M. W. Doherty

2016-11-01

Full Text Available Diamond is a proven solid-state platform for spin-based quantum technology. The nitrogen-vacancy center in diamond has been used to realize small-scale quantum information processing and quantum sensing under ambient conditions. A major barrier in the development of large-scale quantum information processing in diamond is the connection of nitrogen-vacancy spin registers by a quantum bus at room temperature. Given that diamond is expected to be an ideal spin transport material, the coherent transport of spin directly between the spin registers offers a potential solution. Yet, there has been no demonstration of spin transport in diamond due to difficulties in achieving spin injection and detection via conventional methods. Here, we exploit detailed knowledge of the paramagnetic defects in diamond to identify novel mechanisms to photoionize, transport, and capture spin-polarized electrons in diamond at room temperature. Having identified these mechanisms, we explore how they may be combined to realize an on-chip spin quantum bus.

Evaluation of intergranular cracks on the ring header cross at Grand Gulf Unit No. 1

International Nuclear Information System (INIS)

Czajkowski, C.J.

1987-01-01

A metallurgical investigation was performed on a sample of cracked ring header cross material from the Grand Gulf Unit No. 1 Nuclear Power Station. The cracks were located in a 6-7 in (15-17.5 cm) width band running circumferentially below the cross to cap weld with a similar band above the cross to discharger pipe weld. The indications were up to 19 mm in length and 6.0 mm in depth. This particular sample was cut from a cross which had not seen actual service but which had been used to qualify the induction heating stress improvement (IHSI) technique for the Grand Gulf units. The base material was SA 182 material manufactured to SA 403-type WP 304 stainless steel. The investigation consisted of visual/dye penetrant examination, chemical analysis, hardness testing, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The evaluated cracks were intergranular and initiated on the forging's exterior surface. The grain size of the material was larger than ASTM 00 and no definitive corrosive species were found by Energy Dispersive Spectroscopy (EDS). The cracking is considered to be the result of the forging having been overheated/burned during manufacture. (author)

Simulation of uranium transport with variable temperature and oxidation potential: The computer program THCC [Thermo-Hydro-Chemical Coupling

International Nuclear Information System (INIS)

Carnahan, C.L.

1986-12-01

A simulator of reactive chemical transport has been constructed with the capabilities of treating variable temperatures and variable oxidation potentials within a single simulation. Homogeneous and heterogeneous chemical reactions are simulated at temperature-dependent equilibrium, and changes of oxidation states of multivalent elements can be simulated during transport. Chemical mass action relations for formation of complexes in the fluid phase are included explicitly within the partial differential equations of transport, and a special algorithm greatly simplifies treatment of reversible precipitation of solid phases. This approach allows direct solution of the complete set of governing equations for concentrations of all aqueous species and solids affected simultaneously by chemical and physical processes. Results of example simulations of transport, along a temperature gradient, of uranium solution species under conditions of varying pH and oxidation potential and with reversible precipitation of uraninite and coffinite are presented. The examples illustrate how inclusion of variable temperature and oxidation potential in numerical simulators can enhance understanding of the chemical mechanisms affecting migration of multivalent waste elements

Plataformas de colheita e colheita manual com trilha mecânica sobre a qualidade de sementes de arroz ( Oryza sativa, L. Harvest header and manual harvest with mechanical strip on rice ( Oryza sativa, L. seeds quality

Directory of Open Access Journals (Sweden)

Daniel Fernandez Franco

1999-06-01

Full Text Available Durante a colheita do arroz irrigado ocorrem perdas e danos físicos e fisiológicos às sementes. No final da década de oitenta, surgiram as plataformas recolhedoras, que retiram ou arrancam o grão ao invés de cortar a panícula, porém, pouco se conhece a respeito dos danos físicos e fisiológicos que este sistema de plataforma pode causar às sementes. Este trabalho teve por objetivo avaliar os danos mecânicos causados às sementes dos cultivares de arroz BR-IRGA 409 e BR-IRGA 410, por três formas de colheita: (a colheita manual e trilha mecânica; (b colheita com plataforma de corte; (c colheita com plataforma recolhedora. Quando a colheita foi mecânica, realizou-se a coleta das amostras diretamente no graneleiro. O delineamento experimental foi blocos ao acaso, com seis repetições. Os resultados demonstraram que as sementes de arroz irrigado dos cultivares estudados não apresentaram diferenças significativas em suas qualidades físicas e fisiológicas, quando colhidas com plataforma de corte e com a plataforma recolhedora. Estes dois métodos de colheita, porém, apresentaram danos significativamente maiores quando comparados à colheita manual e trilha mecânica.During irrigated rice harvesting occur losses and physical and phisiological seed damage. Late 80's, appeared the strippers headers that strip the grain, instead of cutting the spike. However, little is know about physical and phisiological seed damage by harvest header. The objective of this work was to evaluate the mechanical damage caused to BR-IRGA 409 and BR-IRGA 410 rice cultivars by three harvesting methods: (a manual harvesting and mechanical strip; (b cutterbar harvesting and; (c stripper header harvesting. Samples were collected directly in the grain tank when the harvest was mechanical. The experimental design was randomized blocks with six replications. Results demonstrated that the rice seeds of the studied variety didn't showed significant differences in

Electrical transport properties of graphene nanowalls grown at low temperature using plasma enhanced chemical vapor deposition

Science.gov (United States)

Zhao, Rong; Ahktar, Meysam; Alruqi, Adel; Dharmasena, Ruchira; Jasinski, Jacek B.; Thantirige, Rukshan M.; Sumanasekera, Gamini U.

2017-05-01

In this work, we report the electrical transport properties of uniform and vertically oriented graphene (graphene nanowalls) directly synthesized on multiple substrates including glass, Si/SiO2 wafers, and copper foils using radio-frequency plasma enhanced chemical vapor deposition (PECVD) with methane (CH4) as the precursor at relatively low temperatures. The temperature for optimum growth was established with the aid of transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy. This approach offers means for low-cost graphene nanowalls growth on an arbitrary substrate with the added advantage of transfer-free device fabrication. The temperature dependence of the electrical transport properties (resistivity and thermopower) were studied in the temperature range, 30-300 K and analyzed with a combination of 2D-variable range hopping (VRH) and thermally activated (TA) conduction mechanisms. An anomalous temperature dependence of the thermopower was observed for all the samples and explained with a combination of a diffusion term having a linear temperature dependence plus a term with an inverse temperature dependence.

Effects of temperature anisotropy on neoclassical transport in the plateau and banana-plateau regimes

International Nuclear Information System (INIS)

Taguchi, Masayoshi

1999-01-01

The neoclassical transport theory in a presence of temperature anisotropy is investigated in the low to the intermediate collision frequency regimes for a large aspect-ratio tokamak plasma. The standard procedure for an isotropic plasma in the plateau regime is extended to an anisotropic plasma, and the neoclassical transport coefficients in this regime are explicitly calculated. By interpolating the results in the plateau regime and the previously obtained ones in the banana regime, the expressions for the neoclassical transport coefficients which are continuously valid from the banana to the plateau regimes are presented. (author)

Low temperature carrier transport properties in isotopically controlled germanium

Energy Technology Data Exchange (ETDEWEB)

Itoh, Kohei [Univ. of California, Berkeley, CA (United States)

1994-12-01

Investigations of electronic and optical properties of semiconductors often require specimens with extremely homogeneous dopant distributions and precisely controlled net-carrier concentrations and compensation ratios. The previous difficulties in fabricating such samples are overcome as reported in this thesis by growing high-purity Ge single crystals of controlled ⁷⁵Ge and ⁷⁰Ge isotopic compositions, and doping these crystals by the neutron transmutation doping (NTD) technique. The resulting net-impurity concentrations and the compensation ratios are precisely determined by the thermal neutron fluence and the [⁷⁴Ge]/[⁷⁰Ge] ratios of the starting Ge materials, respectively. This method also guarantees unprecedented doping uniformity. Using such samples the authors have conducted four types of electron (hole) transport studies probing the nature of (1) free carrier scattering by neutral impurities, (2) free carrier scattering by ionized impurities, (3) low temperature hopping conduction, and (4) free carrier transport in samples close to the metal-insulator transition.

A floor cover to improve temperature distribution and quality preservation in maritime refrigerated container transport of grapes

NARCIS (Netherlands)

Lukasse, Leo; Mensink, Manon; Wissink, Edo

2017-01-01

Like many other fruits, table grapes depend on accurate temperature management during transport in maritime refrigerated containers. Ideally the temperature inside the container is equal to set point in every location in the container. Unfortunately door-end temperatures are always higher due to

Low temperature synthesis of graphene on arbitrary substrates and its transport properties

Science.gov (United States)

Zhao, Rong; Akhtar, Meysam; Alruqi, Adel; Jasinski, Jacek; Sumanasekera, Gamini; Department of Physics; Astronomy, University of Louisville Collaboration; Conn CenterRenewable Energy, University of Louisville Collaboration

Here we report the direct synthesis of uniform and vertically oriented graphene films on multiple substrates including glass, Si/SiO2, and copper foil by radio-frequency plasma enhanced chemical vapor deposition (PECVD) using methane as the carbon precursor at relatively low temperatures. Raman spectra of all the samples show characteristic Raman peaks of graphene. The temperature dependence of electrical transport properties such as 4-probe resistance, thermo electrical power and hall mobility were measured for graphene grown on glass substrates at varying temperature from 500 ° C to 700 ° C. The morphological and surface characteristics were also studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This work demonstrates the potential of low temperature and transfer-free graphene growth for future graphene-based electronic applications.

Comparisons of theoretically predicted transport from ion temperature gradient instabilities to L-mode tokamak experiments

International Nuclear Information System (INIS)

Kotschenreuther, M.; Wong, H.V.; Lyster, P.L.; Berk, H.L.; Denton, R.; Miner, W.H.; Valanju, P.

1991-12-01

The theoretical transport from kinetic micro-instabilities driven by ion temperature gradients is a sheared slab is compared to experimentally inferred transport in L-mode tokamaks. Low noise gyrokinetic simulation techniques are used to obtain the ion thermal transport coefficient X. This X is much smaller than in experiments, and so cannot explain L-mode confinement. Previous predictions based on fluid models gave much greater X than experiments. Linear and nonlinear comparisons with the fluid model show that it greatly overestimates transport for experimental parameters. In addition, disagreements among previous analytic and simulation calculations of X in the fluid model are reconciled

Experimental study of electron temperature gradient influence on impurity turbulent transport in fusion plasmas

International Nuclear Information System (INIS)

Villegas, D.

2010-01-01

Understanding impurity transport is a key to an optimal regime for a future fusion device. In this thesis, the theoretical and experimental influence of the electron temperature gradient R/L Te on heavy impurity transport is analyzed both in Tore Supra and ASDEX Upgrade. The electron temperature profile is modified locally by heating the plasma with little ECRH power deposited at two different radii. Experimental results have been obtained with the impurity transport code (ITC) which has been completed with a genetic algorithm allowing to determine the transport coefficient profiles with more accuracy. Transport coefficient profiles obtained by a quasilinear gyrokinetic code named QuaLiKiz are consistent with the experimental ones despite experimental uncertainties on gradients. In the core dominated by electron modes, the lower R/L Te the lower the nickel diffusion coefficient. The latter tends linearly to the neoclassical level when the instability threshold is approached. The experimental threshold is in agreement with the one computed by QuaLiKiz. Further out, where the plasma is dominated by ITG, which are independent of R/L Te , both experimental and simulated results show no modification in the diffusion coefficient profile. Furthermore, the convection velocity profile is not modified. This is attributed to a very small contribution of the thermodiffusion (1/Z dependence) in the total convection. On ASDEX, the preliminary results, very different from the Tore Supra ones, show a internal transport barrier for impurities located at the same radius as the strong ECRH power deposit. (author) [fr

On high temperature strength of carbon steels

International Nuclear Information System (INIS)

Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

1977-01-01

In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

Influence of Magnetic Field on Electric Charge Transport in Holomiun Thin Films at Low Temperatures

Directory of Open Access Journals (Sweden)

Jan Dudas

2005-01-01

Full Text Available Holmium thin films were prepared by evaporation in ultrahigh vacuum (UHV and high precision electrical resistance measurements were performed on them as well as on holomium bulk sample in the wide temperature range from 4,2 K up to the room temperature. Electric charge transport is profoundly influenced by the magnetic structure at low temperatures and a "knee-like" resistance anomaly was observed near the transportation from paramagnetic state to basal-plane spiral structure in bulk with the Neel temperature TN=128,9 K and below ~ 122 K in thin Ho films in a thickness range from 98 nm to 215 nm. Unexpected resistance minimum at ~ 9 K and a slope´s charge of the R vs. T curve near ~ 170 K was observed in 215 nm thin film. Application of magnetic field parallel to the substrate and thin film plane for temperatures below ~ 150 K caused the decrease of resistence value with increasing magnetic flux density. Increasing suppression of the TN value up to ~ 5 K with increasing flux density value up to 5 T was observed in Ho films. 

Temperature dependent transport characteristics of graphene/n-Si diodes

International Nuclear Information System (INIS)

Parui, S.; Ruiter, R.; Zomer, P. J.; Wojtaszek, M.; Wees, B. J. van; Banerjee, T.

2014-01-01

Realizing an optimal Schottky interface of graphene on Si is challenging, as the electrical transport strongly depends on the graphene quality and the fabrication processes. Such interfaces are of increasing research interest for integration in diverse electronic devices as they are thermally and chemically stable in all environments, unlike standard metal/semiconductor interfaces. We fabricate such interfaces with n-type Si at ambient conditions and find their electrical characteristics to be highly rectifying, with minimal reverse leakage current (<10 −10  A) and rectification of more than 10 6 . We extract Schottky barrier height of 0.69 eV for the exfoliated graphene and 0.83 eV for the CVD graphene devices at room temperature. The temperature dependent electrical characteristics suggest the influence of inhomogeneities at the graphene/n-Si interface. A quantitative analysis of the inhomogeneity in Schottky barrier heights is presented using the potential fluctuation model proposed by Werner and Güttler

[The design of heat dissipation of the field low temperature box for storage and transportation].

Science.gov (United States)

Wei, Jiancang; Suin, Jianjun; Wu, Jian

2013-02-01

Because of the compact structure of the field low temperature box for storage and transportation, which is due to the same small space where the compressor, the condenser, the control circuit, the battery and the power supply device are all placed in, the design for heat dissipation and ventilation is of critical importance for the stability and reliability of the box. Several design schemes of the heat dissipation design of the box were simulated using the FLOEFD hot fluid analysis software in this study. Different distributions of the temperature field in every design scheme were constructed intimately in the present study. It is well concluded that according to the result of the simulation analysis, the optimal heat dissipation design is decent for the field low temperature box for storage and transportation, and the box can operate smoothly for a long time using the results of the design.

Transport of temperature-velocity covariance in gas-solid flow and its relation to the axial dispersion coefficient

Science.gov (United States)

Subramaniam, Shankar; Sun, Bo

2015-11-01

The presence of solid particles in a steady laminar flow generates velocity fluctuations with respect to the mean fluid velocity that are termed pseudo-turbulence. The level of these pseudo-turbulent velocity fluctuations has been characterized in statistically homogeneous fixed particle assemblies and freely evolving suspensions using particle-resolved direct numerical simulation (PR-DNS) by Mehrabadi et al. (JFM, 2015), and it is found to be a significant contribution to the total kinetic energy associated with the flow. The correlation of these velocity fluctuations with temperature (or a passive scalar) generates a flux term that appears in the transport equation for the average fluid temperature (or average scalar concentration). The magnitude of this transport of temperature-velocity covariance is quantified using PR-DNS of thermally fully developed flow past a statistically homogeneous fixed assembly of particles, and the budget of the average fluid temperature equation is presented. The relation of this transport term to the axial dispersion coefficient (Brenner, Phil. Trans. Roy. Soc. A, 1980) is established. The simulation results are then interpreted in the context of our understanding of axial dispersion in gas-solid flow. NSF CBET 1336941.

Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

Science.gov (United States)

Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

2014-09-01

Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

Trailer temperature and humidity during winter transport of cattle in Canada and evaluation of indicators used to assess the welfare of cull beef cows before and after transport.

Science.gov (United States)

Goldhawk, C; Janzen, E; González, L A; Crowe, T; Kastelic, J; Kehler, C; Siemens, M; Ominski, K; Pajor, E; Schwartzkopf-Genswein, K S

2015-07-01

The current study evaluated 17 loads of cull beef cows transported in Canadian winter conditions to assess in-transit temperature and humidity, evaluation of events during loading and unloading, and animal condition and bruising. Regardless of the use of boards to block ventilation holes in trailers, temperatures were higher within trailers than at ambient locations during both travel and stationary periods (P cow transport may be related to pretransport animal condition and management of unloading.

Evaluation of stability of allergen extracts for sublingual immunotherapy during transport under unfavourable temperature conditions with an innovative thermal insulating packaging.

Science.gov (United States)

Puccinelli, P; Natoli, V; Dell'albani, I; Scurati, S; Incorvaia, C; Barbieri, S; Masieri, S; Frati, F

2013-10-01

Many pharmaceutical and biotechnological products are temperature-sensitive and should normally be kept at a controlled temperature, particularly during transport, in order to prevent the loss of their stability and activity. Therefore, stability studies should be performed for temperature-sensitive products, considering product characteristics, typical environmental conditions, and anticipating environmental extremes that may occur during product transport in a specific country. Staloral products for sublingual immunotherapy are temperature sensitive and are labelled for maintenance under refrigerated conditions (2-8°C). Given the peculiar climatic context of Italy and the great temperature fluctuations that may occur during transport, this study was aimed at evaluating the impact of a new engineered thermal insulating packaging for Staloral. In particular, the purpose was to assess whether the new packaging could create a container condition able to preserve the stability and immunological activity of the product during the transport phase throughout Italy. The results showed that the range of temperatures that can affect the product, in the area surrounding the product packaging, may reach a peak of 63°C during transport under the most unfavourable climatic conditions, i.e. in a non-refrigerated van during the summer season, from the site of production in France to the patient's house in Catania, the city with the highest temperatures in Italy. However, the highest temperature reached inside the vaccine did not exceed 45°C over a period of about 2 h. The ELISA inhibition test on samples subjected to the extreme temperature conditions previously defined (45°C) showed an immunological activity higher than 75% of that initially measured and was comparable to those obtained with samples stored at controlled temperature (5°C). This means that, even in the worst case scenario, the structure of the allergen extracts is not influenced and the vaccine potency is

User-oriented end-to-end transport protocols for the real-time distribution of telemetry data from NASA spacecraft

Science.gov (United States)

Hooke, A. J.

1979-01-01

A set of standard telemetry protocols for downlink data flow facilitating the end-to-end transport of instrument data from the spacecraft to the user in real time is proposed. The direct switching of data by autonomous message 'packets' that are assembled by the source instrument on the spacecraft is discussed. The data system consists thus of a format on a message rather than word basis, and such packet telemetry would include standardized protocol headers. Standards are being developed within the NASA End-to-End Data System (NEEDS) program for the source packet and transport frame protocols. The source packet protocol contains identification of both the sequence number of the packet as it is generated by the source and the total length of the packet, while the transport frame protocol includes a sequence count defining the serial number of the frame as it is generated by the spacecraft data system, and a field specifying any 'options' selected in the format of the frame itself.

Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications

International Nuclear Information System (INIS)

Wang, Haiyan; Qi, Haiyang; Wang, Weizong; Yan, Joseph D; Geng, Jinyue; Wu, Yaowu

2017-01-01

Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg–Waage equation according to van de Sanden et al ’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman–Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes. (paper)

Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications

Science.gov (United States)

Wang, Haiyan; Wang, Weizong; Yan, Joseph D.; Qi, Haiyang; Geng, Jinyue; Wu, Yaowu

2017-10-01

Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al’s derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto’s electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.

Electronic structure and transport in the low-temperature thermoelectric CsBi₄Te₆: Semiclassical transport equations

DEFF Research Database (Denmark)

Lykke, Lars; Iversen, Bo Brummerstedt; Madsen, Georg

2006-01-01

The band structure of the low-temperature thermoelectric material, CsBi4Te6, is calculated and analyzed using the semiclassic transport equations. It is shown that to obtain a quantitative agreement with measured transport properties, a band gap of 0.08 eV must be enforced. A gap in reasonable...... agreement with experiment was obtained using the generalized gradient functional of Engel and Vosko [E. Engel and S. H. Vosko, Phys. Rev. B 47, 13164 (1993)]. We found that the experimental p-type sample has a carrier concentration close to optimal. Furthermore, the conduction bands have a form equally well...

ELECTRON TEMPERATURE FLUCTUATIONS AND CROSS-FIELD HEAT TRANSPORT IN THE EDGE OF DIII-D

International Nuclear Information System (INIS)

RUDAKOV, DL; BOEDO, JA; MOYER, RA; KRASENINNIKOV, S; MAHDAVI, MA; McKEE, GR; PORTER, GD; STANGEBY, PC; WATKINS, JG; WEST, WP; WHYTE, DG.

2003-01-01

OAK-B135 The fluctuating E x B velocity due to electrostatic turbulence is widely accepted as a major contributor to the anomalous cross-field transport of particles and heat in the tokamak edge and scrape-off layer (SOL) plasmas. This has been confirmed by direct measurements of the turbulent E x B transport in a number of experiments. Correlated fluctuations of the plasma radial velocity v r , density n, and temperature T e result in time-average fluxes of particles and heat given by (for electrons): Equation 1--Λ r ES = r > = 1/B varφ θ ; Equation 2--Q r ES = e (tilde v) r > ∼ 3/2 kT e Λ r ES + 3 n e /2 B varφ e (tilde E) θ > Q conv + Q cond . The first term in Equation 2 is referred to as convective and the second term as conductive heat flux. Experimental determination of fluxes given by Equations 1 and 2 requires simultaneous measurements of the density, temperature and poloidal electric field fluctuations with high spatial and temporal resolution. Langmuir probes provide most readily available (if not the only) tool for such measurements. However, fast measurements of electron temperature using probes are non-trivial and are not always performed. Thus, the contribution of the T e fluctuations to the turbulent fluxes is usually neglected. Here they report results of the studies of T e fluctuations and their effect on the cross-field transport in the SOL of DIII-D

A thermal analysis computer programme package for the estimation of KANUPP coolant channel flows and outlet header temperature distribution

International Nuclear Information System (INIS)

Siddiqui, M.S.

1992-06-01

COFTAN is a computer code for actual estimation of flows and temperatures in the coolant channels of a pressure tube heavy water reactor. The code is being used for Candu type reactor with coolant flowing 208 channels. The simulation model first performs the detailed calculation of flux and power distribution based on two groups diffusion theory treatment on a three dimensional mesh and then channel powers, resulting from the summation of eleven bundle powers in each of the 208 channels, are employed to make actual estimation of coolant flows using channel powers and channel outlet temperature monitored by digital computers. The code by using the design flows in individual channels and applying a correction factor based on control room monitored flows in eight selected channels, can also provide a reserve computational tool of estimating individual channel outlet temperatures, thus providing an alternate arrangements for checking Rads performance. 42 figs. (Orig./A.B.)

Transport critical current measurement apparatus using liquid nitrogen cooled high-T(c) superconducting magnet with variable temperature insert.

Science.gov (United States)

Nishijima, G; Kitaguchi, H; Tshuchiya, Y; Nishimura, T; Kato, T

2013-01-01

We have developed an apparatus to investigate transport critical current (I(c)) as a function of magnetic field and temperature using only liquid nitrogen. The apparatus consists of a (Bi,Pb)(2)Sr(2)Ca(2)Cu(3)O(10) (Bi-2223) superconducting magnet, an outer dewar, and a variable temperature insert (VTI). The magnet, which is operated in depressurized liquid nitrogen, generates magnetic field up to 1.26 T. The sample is also immersed in liquid nitrogen. The pressure in the VTI is controlled from 0.02 to 0.3 MPa, which corresponds to temperature ranging from 66 to 88 K. We have confirmed the long-term stable operation of the Bi-2223 magnet at 1 T. The temperature stability of the sample at high transport current was also demonstrated. The apparatus provides easy-operating I(c) measurement environment for a high-T(c) superconductor up to 500 A in magnetic fields up to 1 T and in temperatures ranging from 66 to 88 K.

Two-temperature transport coefficients of SF{sub 6}–N{sub 2} plasma

Energy Technology Data Exchange (ETDEWEB)

Yang, Fei; Chen, Zhexin; Wu, Yi, E-mail: wuyic51@mail.xjtu.edu.cn; Rong, Mingzhe; Wang, Chunlin [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Guo, Anxiang; Liu, Zirui [Electric Power Research Institute of State Grid Shaanxi Electric Power Company, Xian (China)

2015-10-15

Sulfur hexafluoride (SF{sub 6}) is widely adopted in electric power industry, especially in high-voltage circuit breakers and gas-insulated switchgear. However, the use of SF{sub 6} is limited by its high liquidation temperature and high global warming potential. Recently, research shows SF{sub 6}–N{sub 2} mixture, which shows environmental friendliness and good electrical properties, may be a feasible substitute for pure SF{sub 6}. This paper is devoted to the calculation of and transport coefficients of SF{sub 6}–N{sub 2} mixture under both LTE (local thermodynamic equilibrium) and non-LTE condition. The two–temperature mass action law was used to determine the composition. The transport coefficients were calculated by classical Chapman–Enskog method simplified by Devoto. The thermophysical properties are presented for electron temperatures of 300–40 000 K, ratios of electron to heavy species temperature of 1–10 and N{sub 2} mole fraction of 0%–100% at atmospheric pressure. The ionization processes under both LTE and non-LTE have been discussed. The results show that deviations from local thermodynamic equilibrium significantly affect the properties of SF{sub 6}–N{sub 2} plasma, especially before the plasma is fully ionized. The different influence of N{sub 2} on properties for SF{sub 6}–N{sub 2} plasma in and out of LTE has been found. The results will serve as reliable reference data for computational simulation of the behavior of SF{sub 6}–N{sub 2} plasmas.

Overnight storage of whole blood: cooling and transporting blood at room temperature under extreme temperature conditions.

Science.gov (United States)

Thibault, L; Beauséjour, A; Jacques, A; Ducas, E; Tremblay, M

2014-02-01

Many countries allow the overnight storage of whole blood (WB) at ambient temperature. Some countries, such as Canada, also require a rapid cooling of WB with an active cooling system. Given the significant operational constraints associated with current cooling systems, an alternative method for cooling and transporting WB at 20-24°C was evaluated. Phase 22 cooling packs (TCP Reliable Inc., USA) were used in combination with vacuum-insulated panel (VIP) boxes. Temperature profiles of simulated WB units were studied in extreme temperatures (-35 and 40°C). The quality of blood components prepared using Phase 22 packs and CompoCool-WB (Fresenius HemoCare, Germany) was studied. Phase 22 packs reduced the temperature of simulated WB bags from 37 to 24°C in 1·7 ± 0·2 h. Used in combination with VIP boxes, Phase 22 packs maintain the temperature of bags between 20 and 24°C for 15 and 24 h, compared to 2 and 11 h with CompoCool-WB, when exposed at -35 and 40°C, respectively. The quality of platelet concentrates and plasma was comparable, regardless of the cooling system used. For red blood cell units, per cent haemolysis on day 42 was slightly higher in products prepared after cooling with Phase 22 packs compared to CompoCool-WB (0·33 ± 0·15% vs. 0·21 ± 0·06%; P environmental conditions. © 2013 International Society of Blood Transfusion.

Development of CANDU 6 Primary Heat Transport System Modeling Program

International Nuclear Information System (INIS)

Seo, Hyung-beom; Kim, Sung-min; Park, Joong-woo; Kim, Kwang-su; Ko, Dae-hack; Han, Bong-seob

2007-01-01

NUCIRC is a steady-state thermal-hydraulic code used for design and performance analyses of CANDU Heat Transport System. The code is used to build PHT model in Wolsong NPP and to calculate channel flow distribution. Wolsong NPP has to calculate channel flow distribution and quality of coolant at the ROH header after every outage by OPP (Operating Policy and Principal). PHT modeling work is time consuming which need a lot of operation experience and specialty. It is very difficult to build PHT model as plant operator in two weeks which is obligate for plant operation after every outage. That is why Wolsong NPP develop NUMODEL (NUcirc MODELing) with many-years experience and a know-how of using NUCIRC code. NUMODEL is computer program which is used to create PHT model based on utilizing NUCIRC code

Tanker for the transport of very low temperature liquids at atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Messer, E S

1968-02-08

This tanker for the transport of very low temperature liquids, especially liquefied methane or natural gas, has a large capacity reservoir insulated on the outside. A second reservoir in the bottom of the hull, below the main reservoir, collects liquid leaking out from the main reservoir and is equipped with a drain pipe. The pipe serving to fill and to empty the main reservoir passes through this second reservoir. (4 claims)

HTGR power plant hot reheat steam pressure control system

International Nuclear Information System (INIS)

Braytenbah, A.S.; Jaegtnes, K.O.

1975-01-01

A control system for a high temperature gas cooled reactor (HTGR) power plant is disclosed wherein such plant includes a plurality of steam generators. Dual turbine-generators are connected to the common steam headers, a high pressure element of each turbine receiving steam from the main steam header, and an intermediate-low pressure element of each turbine receiving steam from the hot reheat header. Associated with each high pressure element is a bypass line connected between the main steam header and a cold reheat header, which is commonly connected to the high pressure element exhausts. A control system governs the flow of steam through the first and second bypass lines to provide for a desired minimum steam flow through the steam generator reheater sections at times when the total steam flow through the turbines is less than such minimum, and to regulate the hot reheat header steam pressure to improve control of the auxiliary steam turbines and thereby improve control of the reactor coolant gas flow, particularly following a turbine trip. (U.S.)

Charge transport in poly(p-phenylene vinylene) at low temperature and high electric field

NARCIS (Netherlands)

Katsouras, I.; Najafi, A.; Asadi, K.; Kronemeijer, A. J.; Oostra, A. J.; Koster, L. J. A.; de Leeuw, D. M.; Blom, P. W. M.

Charge transport in poly(2-methoxy, 5-(2'-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV)-based hole-only diodes is investigated at high electric fields and low temperatures using a novel diode architecture. Charge carrier densities that are in the range of those in a field-effect transistor are

Effect of electronic contribution on temperature-dependent thermal transport of antimony telluride thin film

Energy Technology Data Exchange (ETDEWEB)

Lee, Won-Yong; Park, No-Won [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hong, Ji-Eun [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Yoon, Soon-Gil, E-mail: sgyoon@cnu.ac.kr [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Koh, Jung-Hyuk [School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Sang-Kwon, E-mail: sangkwonlee@cau.ac.kr [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

2015-01-25

Highlights: • We investigated thermal transport of the antimony telluride thin films. • The contribution of the electronic thermal conductivity increased up to ∼77% at 300 K. • We theoretically analyze and explain the high contribution of electronic component. - Abstract: We study the theoretical and experimental characteristics of thermal transport of 100 nm and 500 nm-thick antimony telluride (Sb{sub 2}Te{sub 3}) thin films prepared by radio frequency magnetron sputtering. The thermal conductivity was measured at temperatures ranging from 20 to 300 K, using four-point-probe 3-ω method. Out-of-plane thermal conductivity of the Sb{sub 2}Te{sub 3} thin film was much lesser in comparison to the bulk material in the entire temperature range, confirming that the phonon- and electron-boundary scattering are enhanced in thin films. Moreover, we found that the contribution of the electronic thermal conductivity (κ{sub e}) in total thermal conductivity (κ) linearly increased up to ∼77% at 300 K with increasing temperature. We theoretically analyze and explain the high contribution of electronic component of thermal conductivity towards the total thermal conductivity of the film by a modified Callaway model. Further, we find the theoretical model predictions to correspond well with the experimental results.

Estimation of edge electron temperature profiles via forward modelling of the electron cyclotron radiation transport at ASDEX Upgrade

International Nuclear Information System (INIS)

Rathgeber, S K; Barrera, L; Eich, T; Fischer, R; Suttrop, W; Wolfrum, E; Nold, B; Willensdorfer, M

2013-01-01

We present a method to obtain reliable edge profiles of the electron temperature by forward modelling of the electron cyclotron radiation transport. While for the core of ASDEX Upgrade plasmas, straightforward analysis of electron cyclotron intensity measurements based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin plasma edge needs to consider broadened emission and absorption profiles and radiation transport processes. This is carried out in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different interdependent and complementary diagnostics. By this means, electron cyclotron radiation intensity delivers highly spatially resolved electron temperature data for the plasma edge. In H-mode, the edge gradient of the electron temperature can be several times higher than the one of the radiation temperature. Furthermore, we are able to reproduce the ‘shine-through’ peak—the observation of increased radiation temperatures at frequencies resonant in the optically thin scrape-off layer. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. (paper)

First application of a partially automated road header at Prosper-Haniel colliery; Ersteinsatz einer teilautomatisierten Teilschnittmaschine auf dem Bergwerk Prosper-Haniel

Energy Technology Data Exchange (ETDEWEB)

Reinewardt, Klaus-Juergen [Bergwerk Prosper-Haniel, Bottrop (Germany). Betrieb Produktion; Achilles, Peter [RAG Deutsche Steinkohle AG, Herne (Germany). Abt. PPE-V Vorleistungstechnik

2010-09-15

Mechanical road heading in the RAG Deutsche Steinkohle mines makes use of AM 105 road headers. Within the scope of an EU-subsidised R and D project the machine has been subjected to an automation of its control features and an integration of sensors for seam position identification and for navigation. The focal points of the automation are: - the scheduled performance of automated cutting operations, - the adherence to a defined loading height due to seam position identification and - the incorporation of first auxiliary functions for navigation (position sensing). In addition, the machine is expected to determine its respective functional state and recognised potential functional faults by itself, and - subject to its present load condition - it is to deliver the basis for a maintenance scheme geared to its current condition. This paper describes above-mentioned development steps and reports on the experience gathered in the underground use of that machine in the Prosper-Haniel colliery. (orig.)

[Dynamics of change of ureaplasma laboratory strain titers and quantity of their DNA in transport medium at varying temperature].

Science.gov (United States)

Gamova, N A; Ivanova, T A

2013-01-01

Study of preservation dynamics of ureaplasma laboratory strain live cultures and their DNA in transport medium at varying temperature. The study was carried out in laboratory strains Ureaplasma urealyticum serotype 8 and Ureaplasma parvum serotype 1. The quantity of live ureaplasmas was determined by method of tenfold dilutions in liquid medium. The growth of ureaplasmas was registered by changes in the color of the cultivation medium due to its alkalization by metabolism products and expressed in CCU/ml. DNA quantity in samples was determined by real time PCR performed by using Florocenosis-micoplasmas-FL test system produced by ILS. Live ureaplasmas wer shown to be preserved in transport medium at 4 degrees C for 12 - 29 days, at 18 - 22 degrees C--for 9 - 20 days and at 37 degrees C--for only 2 days. In samples incubated at 37 degrees C the quantity of live ureaplasmas increased and then sharply decreased to 0, at lower temperature titers of the cells decreased smoothly. The quantity of ureaplasma DNA in the process of their incubation did not change significantly. Fundamental differences in the duration of survival of U. urealyticum strain and U. parvum strain in transport medium at varying temperature were not detected. Based on the studies performed a practical conclusion can be drawn that in cases of emergency when clinical material transportation is necessary its storage in transport medium for several days is acceptable.

Transport properties of glass-forming liquids suggest that dynamic crossover temperature is as important as the glass transition temperature.

Science.gov (United States)

Mallamace, Francesco; Branca, Caterina; Corsaro, Carmelo; Leone, Nancy; Spooren, Jeroen; Chen, Sow-Hsin; Stanley, H Eugene

2010-12-28

It is becoming common practice to partition glass-forming liquids into two classes based on the dependence of the shear viscosity η on temperature T. In an Arrhenius plot, ln η vs 1/T, a strong liquid shows linear behavior whereas a fragile liquid exhibits an upward curvature [super-Arrhenius (SA) behavior], a situation customarily described by using the Vogel-Fulcher-Tammann law. Here we analyze existing data of the transport coefficients of 84 glass-forming liquids. We show the data are consistent, on decreasing temperature, with the onset of a well-defined dynamical crossover η(×), where η(×) has the same value, η(×) ≈ 10(3) Poise, for all 84 liquids. The crossover temperature, T(×), located well above the calorimetric glass transition temperature T(g), marks significant variations in the system thermodynamics, evidenced by the change of the SA-like T dependence above T(×) to Arrhenius behavior below T(×). We also show that below T(×) the familiar Stokes-Einstein relation D/T ∼ η(-1) breaks down and is replaced by a fractional form D/T ∼ η(-ζ), with ζ ≈ 0.85.

The steady-state and transient electron transport within bulk zinc-blende indium nitride: The impact of crystal temperature and doping concentration variations

International Nuclear Information System (INIS)

Siddiqua, Poppy; O'Leary, Stephen K.

2016-01-01

Within the framework of a semi-classical three-valley Monte Carlo electron transport simulation approach, we analyze the steady-state and transient aspects of the electron transport within bulk zinc-blende indium nitride, with a focus on the response to variations in the crystal temperature and the doping concentration. We find that while the electron transport associated with zinc-blende InN is highly sensitive to the crystal temperature, it is not very sensitive to the doping concentration selection. The device consequences of these results are then explored.

Self-consistent transport coefficients for average collective motion at moderately high temperatures

International Nuclear Information System (INIS)

Yamaji, Shuhei; Hofmann, H.; Samhammer, R.

1987-01-01

Linear response theory is applied to compute the coefficients for inertia, friction and local stiffness for slow, large scale nuclear collective motion. It is shown how these coefficients can be defined within a locally harmonic approximation. The latter allows to study the implications arising from a finite local collective frequency. It is only for temperatures around 2 MeV that the zero frequency limit becomes a fair approximation. Friction is found to have a marked temperature dependence. The numerical computations are performed on the basis of a two-center shell model, but allowing the particles and holes to become dressed through effects of the medium. The dependence of the transport coefficients on the parameters of these self-energies is studied. It is argued that the uncertainties are smaller than a factor of 2. (orig.)

Transport and contact-free investigation of REBCO thin film temperature dependent pinning landscapes

Science.gov (United States)

Sinclair, John; Jaroszynski, Jan; Hu, Xinbo; Santos, Michael

2013-03-01

Studies of the pinning mechanisms and landscapes of REBa2Cu3Ox (RE=rare earth elements) thin films have been a topic of study in recent years due to, among other reasons, their ability to introduce nonsuperconducting phases and defects. Here we will focus on REBCO thin films with BaZrO3 nanocolumns and other isotropic defects. The evolution of the dominant pinning mechanisms seems to change as a function of temperature even to the point that samples with similar critical current density properties at high temperatures can have distinctly different properties at low temperatures. Earlier work focused on the angular selectivity of the current density profile, though other properties (such as alpha values) can evolve as well. Characteristic results accentuating this evolution of current density properties will be presented. Challenges exist in evaluating these low temperature properties in high magnetic fields, therefore both transport and contact-free results were be presented to compliment the work. Support for this work is provided by the NHMFL via NSF DRM 0654118.

An investigation on high-temperature electrical transport properties of graphene-oxide nano-thinfilms

International Nuclear Information System (INIS)

Venugopal, Gunasekaran; Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

2013-01-01

High-temperature electrical transport properties are investigated for graphene-oxide nano thinfilms. The graphene-oxide nanoparticles are synthesized by modified Hummers method and characterized by UV–vis, Raman and X-ray diffraction techniques. The surface morphology of graphene-oxide film is analyzed using scanning electron and atomic force microscopy. The experimental results on high-temperature electrical studies of thinfilms exhibit metallic behavior followed by three-dimensional variable range hopping mechanism. The current–voltage characteristics at various temperatures (from 293 K to 573 K) were investigated. The effect of high-temperature on the functional groups of graphene-oxide film is evidently examined using X-ray photoelectron, thermal gravimetric analysis and Fourier transform infra-red spectroscopy. Transistor characteristics were performed after heat treatment resulting ambipolar behavior with holes and electron mobility of 127 and 66.9 cm 2 V −1 s −1 respectively. Our results are comparable to reduced graphene-oxide, indicating the advantage of our approach requires no further reduction to develop graphene-based transparent and conductive electrodes for dye-sensitized solar cells and ultra-capacitor applications.

Coherent quantum transport in disordered systems: II. Temperature dependence of carrier diffusion coefficients from the time-dependent wavepacket diffusion method

International Nuclear Information System (INIS)

Zhong, Xinxin; Zhao, Yi; Cao, Jianshu

2014-01-01

The time-dependent wavepacket diffusion method for carrier quantum dynamics (Zhong and Zhao 2013 J. Chem. Phys. 138 014111), a truncated version of the stochastic Schrödinger equation/wavefunction approach that approximately satisfies the detailed balance principle and scales well with the size of the system, is applied to investigate the carrier transport in one-dimensional systems including both the static and dynamic disorders on site energies. The predicted diffusion coefficients with respect to temperature successfully bridge from band-like to hopping-type transport. As demonstrated in paper I (Moix et al 2013 New J. Phys. 15 085010), the static disorder tends to localize the carrier, whereas the dynamic disorder induces carrier dynamics. For the weak dynamic disorder, the diffusion coefficients are temperature-independent (band-like property) at low temperatures, which is consistent with the prediction from the Redfield equation, and a linear dependence of the coefficient on temperature (hopping-type property) only appears at high temperatures. In the intermediate regime of dynamic disorder, the transition from band-like to hopping-type transport can be easily observed at relatively low temperatures as the static disorder increases. When the dynamic disorder becomes strong, the carrier motion can follow the hopping-type mechanism even without static disorder. Furthermore, it is found that the memory time of dynamic disorder is an important factor in controlling the transition from the band-like to hopping-type motions. (paper)

Effect of room temperature lattice vibration on the electron transport in graphene nanoribbons

Science.gov (United States)

Liu, Yue-Yang; Li, Bo-Lin; Chen, Shi-Zhang; Jiang, Xiangwei; Chen, Ke-Qiu

2017-09-01

We observe directly the lattice vibration and its multifold effect on electron transport in zigzag graphene nanoribbons in simulation by utilizing an efficient combined method. The results show that the electron transport fluctuates greatly due to the incessant lattice vibration of the nanoribbons. More interestingly, the lattice vibration behaves like a double-edged sword that it boosts the conductance of symmetric zigzag nanoribbons (containing an even number of zigzag chains along the width direction) while weakens the conductance of asymmetric nanoribbons. As a result, the reported large disparity between the conductances of the two kinds of nanoribbons at 0 K is in fact much smaller at room temperature (300 K). We also find that the spin filter effect that exists in perfect two-dimensional symmetric zigzag graphene nanoribbons is destroyed to some extent by lattice vibrations. Since lattice vibrations or phonons are usually inevitable in experiments, the research is very meaningful for revealing the important role of lattice vibrations play in the electron transport properties of two-dimensional materials and guiding the application of ZGNRs in reality.

Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors

International Nuclear Information System (INIS)

Chang Oh; Cliff Davis; Rober Barner; Paul Pickard

2005-01-01

The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed to perform thermal-hydraulic evaluations and cycle-efficiency evaluations of the different configurations and coolants. The thermal-hydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. The relative sizes of components provide a relative indication of the capital cost associated with the various configurations. Estimates of the overall cycle efficiency of the various

Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

International Nuclear Information System (INIS)

Kirchheim, Dennis; Jaritz, Montgomery; Hopmann, Christian; Dahlmann, Rainer; Mitschker, Felix; Awakowicz, Peter; Gebhard, Maximilian; Devi, Anjana; Brochhagen, Markus; Böke, Marc

2017-01-01

Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments. (paper)

Changes of the more relevant PHTS parameters after the cleaning of the steam generators primary side at Embalse nuclear power plant

International Nuclear Information System (INIS)

Moreno, Carlos A.; Coutsiers, Ernesto; Acevedo, Paul; Pomerantz, Marcelo E.

2003-01-01

During the operation of the plant magnetite deposition occurs at the inner walls of Primary Heat Transport System (PHTS). This deposition is particularly significant at the U-tubes of steam generators. The consequence of this is the deterioration of heat transfer to the Secondary System. In order to minimize this impact, during the annual outage of 2000, the steam generators primary side cleaning by the SIVABLAST technique was carried out. This technique consists in blasting the inner walls with tiny stainless steel balls propelled by air at high pressure. This paper presents the change of the more relevant parameters of PHTS after that cleaning. The parameters analyzed and the main results are the following: 1) Inlet header temperature dropped 4.7 C degrees at full power; 2) Exit quality at the outlet headers decreased from 3,5% to 1,5%; 3) Global PHTS flow in single phase evaluated from: a) In-site instrumentation increased 4,6%; b) Thermalhydraulic code NUCIRC 1.0 increased 3,2%; c) measured flows at the instrumented fuel channels increased 4.4%. (author)

Tractable flux-driven temperature, density, and rotation profile evolution with the quasilinear gyrokinetic transport model QuaLiKiz

Science.gov (United States)

Citrin, J.; Bourdelle, C.; Casson, F. J.; Angioni, C.; Bonanomi, N.; Camenen, Y.; Garbet, X.; Garzotti, L.; Görler, T.; Gürcan, O.; Koechl, F.; Imbeaux, F.; Linder, O.; van de Plassche, K.; Strand, P.; Szepesi, G.; Contributors, JET

2017-12-01

Quasilinear turbulent transport models are a successful tool for prediction of core tokamak plasma profiles in many regimes. Their success hinges on the reproduction of local nonlinear gyrokinetic fluxes. We focus on significant progress in the quasilinear gyrokinetic transport model QuaLiKiz (Bourdelle et al 2016 Plasma Phys. Control. Fusion 58 014036), which employs an approximated solution of the mode structures to significantly speed up computation time compared to full linear gyrokinetic solvers. Optimisation of the dispersion relation solution algorithm within integrated modelling applications leads to flux calculations × {10}6-7 faster than local nonlinear simulations. This allows tractable simulation of flux-driven dynamic profile evolution including all transport channels: ion and electron heat, main particles, impurities, and momentum. Furthermore, QuaLiKiz now includes the impact of rotation and temperature anisotropy induced poloidal asymmetry on heavy impurity transport, important for W-transport applications. Application within the JETTO integrated modelling code results in 1 s of JET plasma simulation within 10 h using 10 CPUs. Simultaneous predictions of core density, temperature, and toroidal rotation profiles for both JET hybrid and baseline experiments are presented, covering both ion and electron turbulence scales. The simulations are successfully compared to measured profiles, with agreement mostly in the 5%-25% range according to standard figures of merit. QuaLiKiz is now open source and available at www.qualikiz.com.

Electron thermal energy transport research based on dynamical relationship between heat flux and temperature gradient

International Nuclear Information System (INIS)

Notake, Takashi; Inagaki, Shigeru; Tamura, Naoki

2008-01-01

In the nuclear fusion plasmas, both of thermal energy and particle transport governed by turbulent flow are anomalously enhanced more than neoclassical levels. Thus, to clarify a relationship between the turbulent flow and the anomalous transports has been the most worthwhile work. There are experimental results that the turbulent flow induces various phenomena on transport processes such as non-linearity, transition, hysteresis, multi-branches and non-locality. We are approaching these complicated problems by analyzing not conventional power balance but these phenomena directly. They are recognized as dynamical trajectories in the flux and gradient space and must be a clue to comprehend a physical mechanism of arcane anomalous transport. Especially, to elucidate the mechanism for electron thermal energy transport is critical in the fusion plasma researches because the burning plasmas will be sustained by alpha-particle heating. In large helical device, the dynamical relationships between electron thermal energy fluxes and electron temperature gradients are investigated by using modulated electron cyclotron resonance heating and modern electron cyclotron emission diagnostic systems. Some trajectories such as hysteresis loop or line segments with steep slope which represent non-linear property are observed in the experiment. (author)

Relationship between temperament and transportation with rectal temperature and secretion of cortisol and epinephrine in bulls

Science.gov (United States)

This study investigated whether temperament influences rectal temperature and the secretion of cortisol and epinephrine in response to transportation. Brahman bulls were selected based on temperament score (average of exit velocity, EV, and pen score, PS) measured 28 days prior to weaning with the 8...

Effect of egg storage duration and brooding temperatures on chick growth, intestine morphology and nutrient transporters.

Science.gov (United States)

Yalcin, S; Gursel, I; Bilgen, G; Horuluoglu, B H; Gucluer, G; Izzetoglu, G T

2017-10-01

The effects of egg storage duration (ESD) and brooding temperature (BT) on BW, intestine development and nutrient transporters of broiler chicks were investigated. A total of 396 chicks obtained from eggs stored at 18°C for 3 days (ESD3-18°C) or at 14°C for 14 days (ESD14-14°C) before incubation were exposed to three BTs. Temperatures were initially set at 32°C, 34°C and 30°C for control (BT-Cont), high (BT-High) and low (BT-Low) BTs, respectively. Brooding temperatures were decreased by 2°C each at days 2, 7, 14 and 21. Body weight was measured at the day of hatch, 2, 7, 14, 21, 28 and 42. Cloacal temperatures of broilers were recorded from 1 to 14 days. Intestinal morphology and gene expression levels of H+-dependent peptide transporter (PepT1) and Na-dependent glucose (SGLT1) were evaluated on the day of hatch and 14. Cloacal temperatures of chicks were affected by BTs from days 1 to 8, being the lowest for BT-Low chicks. BT-High resulted in the heaviest BWs at 7 days, especially for ESD14-14°C chicks. This result was consistent with longer villus and larger villus area of ESD14-14°C chicks at BT-High conditions. From 14 days to slaughter age, BT had no effect on broiler weight. ESD3-18°C chicks were heavier than ESD14-14°C chicks up to 28 days. The PepT1 and SGLT1 expression levels were significantly higher in ESD3-18°C chicks than ESD14-14°C on the day of hatch. There was significant egg storage by BT interaction for PepT1 and SGLT1 transporters at day 14. ESD14-14°C chicks had significantly higher expression of PepT1 and SGLT1 at BT-Low than those at BT-Cont. ESD14-14°C chicks upregulated PepT1 gene expression 1.15 and 1.57-fold at BT-High and BT-Low, respectively, compared with BT-Cont, whereas PepT1 expression was downregulated 0.67 and 0.62-fold in ESD3-18°C chicks at BT-High and BT-Low. These results indicated that pre-incubation egg storage conditions and BTs affected intestine morphology and PepT1 and SGLT1 nutrient transporters

Exponential temperature dependence of the critical transport current in Y-Ba-Cu-O thin films

International Nuclear Information System (INIS)

Yom, S.S.; Hahn, T.S.; Kim, Y.H.; Chu, H.; Choi, S.S.

1989-01-01

We have measured the critical currents in rf-sputtered YBa 2 Cu 3 O/sub 7-x/ thin films deposited on polycrystalline yttria-stabilized zirconia substrates as a function of temperature down to 10 K. The dependence of the granular films at low temperature indicated exponential behavior which is similar to the superconductor-normal metal-superconductor (S-N-S) type tunneling junctions. For the films with a grain size of approximately 1 μm, we observed two exponential decay constants, which suggest that Josephson junctions limiting the transport critical current are possible both at the grain boundaries and at twin boundaries

Electrical transport and temperature coefficient of resistance in polycrystalline La0.7−xAgxCa0.3MnO3 pellets: Analysis in terms of a phase coexistence transport model and phase separation model

International Nuclear Information System (INIS)

Phong, P.T.; Nguyen, L.H.; Manh, D.H.; Phuc, N.X.; Lee, I.-J.

2013-01-01

The temperature dependent resistivity and temperature coefficient of resistance of Ag doped La 0.7−x Ag x Ca 0.3 MnO 3 polycrystalline pellets (x=0, 0.05, 0.10, 0.15, and 0.20) are investigated. Ag substitution enhances the conductivity of this system. The Curie temperature also increases from 260 to 283 K with increasing Ag content. Using phase-coexistence transport model and phase separation model, we calculated the resistivity as a function of temperature and the temperature coefficient of resistivity (TCR) behavior. Comparing the calculated maximum TCR, we found that it is related to activation energy, transition temperature, and disorder in doped manganites. The relationship between the proposed TCR behavior and the transport parameters can suggest conditions improving TCR max of doped manganites for the use of the bolometric infrared detectors

Low-temperature thermal transport and thermopower of monolayer transition metal dichalcogenide semiconductors

Science.gov (United States)

Sengupta, Parijat; Tan, Yaohua; Klimeck, Gerhard; Shi, Junxia

2017-10-01

We study the low temperature thermal conductivity of single-layer transition metal dichalcogenides (TMDCs). In the low temperature regime where heat is carried primarily through transport of electrons, thermal conductivity is linked to electrical conductivity through the Wiedemann-Franz law (WFL). Using a k.p Hamiltonian that describes the K and K{\\prime} valley edges, we compute the zero-frequency electric (Drude) conductivity using the Kubo formula to obtain a numerical estimate for the thermal conductivity. The impurity scattering determined transit time of electrons which enters the Drude expression is evaluated within the self-consistent Born approximation. The analytic expressions derived show that low temperature thermal conductivity (1) is determined by the band gap at the valley edges in monolayer TMDCs and (2) in presence of disorder which can give rise to the variable range hopping regime, there is a distinct reduction. Additionally, we compute the Mott thermopower and demonstrate that under a high frequency light beam, a valley-resolved thermopower can be obtained. A closing summary reviews the implications of results followed by a brief discussion on applicability of the WFL and its breakdown in context of the presented calculations.

Implications of Thermal Diffusity being Inversely Proportional to Temperature Times Thermal Expansivity on Lower Mantle Heat Transport

Science.gov (United States)

Hofmeister, A.

2010-12-01

Many measurements and models of heat transport in lower mantle candidate phases contain systematic errors: (1) conventional methods of insulators involve thermal losses that are pressure (P) and temperature (T) dependent due to physical contact with metal thermocouples, (2) measurements frequently contain unwanted ballistic radiative transfer which hugely increases with T, (3) spectroscopic measurements of dense samples in diamond anvil cells involve strong refraction by which has not been accounted for in analyzing transmission data, (4) the role of grain boundary scattering in impeding heat and light transfer has largely been overlooked, and (5) essentially harmonic physical properties have been used to predict anharmonic behavior. Improving our understanding of the physics of heat transport requires accurate data, especially as a function of temperature, where anharmonicity is the key factor. My laboratory provides thermal diffusivity (D) at T from laser flash analysis, which lacks the above experimental errors. Measuring a plethora of chemical compositions in diverse dense structures (most recently, perovskites, B1, B2, and glasses) as a function of temperature provides a firm basis for understanding microscopic behavior. Given accurate measurements for all quantities: (1) D is inversely proportional to [T x alpha(T)] from ~0 K to melting, where alpha is thermal expansivity, and (2) the damped harmonic oscillator model matches measured D(T), using only two parameters (average infrared dielectric peak width and compressional velocity), both acquired at temperature. These discoveries pertain to the anharmonic aspects of heat transport. I have previously discussed the easily understood quasi-harmonic pressure dependence of D. Universal behavior makes application to the Earth straightforward: due to the stiffness and slow motions of the plates and interior, and present-day, slow planetary cooling rates, Earth can be approximated as being in quasi

Evaluation of effect of inlet distortion on aerodynamic performance of helium gas compressor for gas turbine high temperature reactor (GTHTR300). Contract research

International Nuclear Information System (INIS)

Takada, Shoji; Takizuka, Takakazu; Yan, Xing; Kurokouchi, Naohiro; Kunitomi, Kazuhiko

2006-02-01

Because the main pipe is connected perpendicular to the flow direction inside the distributing header in the inlet casing of the helium gas compressor design of GTHTR300, the main flow flowing into the header tends to separate from the header wall and to cause reverse flow, which increases flow resistance in the header. This phenomenon increases the total pressure loss in the header and inlet distortion, which is considered to deteriorate the aerodynamic performance of the compressor. Tests were carried out to evaluate the effects of inlet distortion on aerodynamic performance of compressor by using a 1/3-scale helium gas compressor model by varying a level of inlet distortion. Flow was injected from the wall of header to make circumferential velocities uniform before and after the reverse flow region to dissipate the separation and reverse flow. At the design point, inlet distortion was reduced by 2-3% by injection, which resulted in increasing adiabatic efficiency of blade section by 0.5%. A modified flow rate at surge point was lowered from 10.0 kg/s to 9.6 kg/s. At the same time, pressure loss of the inlet casing was reduced by 3-5 kPa, which is equivalent to adiabatic efficiency improvement around 0.8%. By setting orifice at the inlet of the inlet casing, the level of inlet distortion became 3% higher and the adiabatic efficiency of blade section became 1% higher at the design point. The modified flow rate at surge point increased from 10.6 to 10.9 kg/s. A new correlation between inlet distortion and adiabatic efficiency of blade section at the rated flow rate was derived based on compressor-in-parallel model and fitted to the test results. An overall adiabatic efficiency of full-scale compressor was predicted 90.2% based on the test results of efficiency and Reynolds number correlation, which was close to 89.7% that was predicted by test calibrated design through-flow code. (author)

A newly developed container for safe, easy, and cost-effective overnight transportation of tissues and organs by electrically keeping tissue or organ temperature at 3 to 6°C.

Science.gov (United States)

Ohkawara, H; Kitagawa, T; Fukushima, N; Ito, T; Sawa, Y; Yoshimine, T

2012-05-01

As there is only one skin procurement organization in Japan the Japan Skin Bank Network (JSBN), all skin grafts procured in Japan are sent by a commercialized delivery system. Preliminarily, bottles containing saline were transported in a cardboard box using a so-called "cooled home delivery service" using a truck with a refrigerated cargo container. During transportation the temperature in the cardboard box increased to 18°C in summer and decreased to -5°C in winter. For these reasons, we investigated whether a newly developed container "Medi Cube" would be useful to transport skin grafts. Four bottles with a capacity of 300 mL containing 150 mL of saline in a Medi Cube container were transported from Osaka to the JSBN in Tokyo between 4 PM and 10 AM using a commercialized cooled home delivery service. Two bottles were transported in a Medi Cube container without phase change materials (PCM) in winter and summer, respectively. Another two bottles were transported in the Medi Cube with PCMs in winter. The temperatures inside saline, inside a transportation container, and outside the container, and air temperature were monitored continuously with a recordable thermometer. The temperatures inside saline and inside a Medi Cube container were maintained between 3 and 6°C, even when the temperature outside the container increased during parking. The temperature inside a Medi Cube container without PCM decreased to -3°C when the inside of the cargo container was overcooled in winter. However, the temperatures inside saline and inside a Medi Cube container with PCM were between 3 and 6°C, even when the temperature outside the container decreased to below 0°C in winter. A Medi Cube container with PCM provided a safe, easy, and cost-effective method for overnight transportation of skin grafts. Copyright © 2012 Elsevier Inc. All rights reserved.

Temperature-dependent electrical characteristics and carrier transport mechanism of p-Cu2ZnSnS4/n-GaN heterojunctions

Science.gov (United States)

Niteesh Reddy, Varra; Reddy, M. Siva Pratap; Gunasekhar, K. R.; Lee, Jung-Hee

2018-04-01

This work explores the temperature-dependent electrical characteristics and carrier transport mechanism of Au/p-Cu2ZnSnS4/n-type GaN heterojunction (HJ) diodes with a CZTS interlayer. The electrical characteristics were examined by current-voltage-temperature, turn-on voltage-temperature and series resistance-temperature in the high-temperature range of 300-420 K. It is observed that an exponential decrease in the series resistance ( R S) and increase in the ideality factor ( n) and barrier height ( ϕ b) with increase in temperature. The thermal coefficient ( K j) is determined to be - 1.3 mV K-1 at ≥ 300 K. The effective ϕ b is determined to be 1.21 eV. This obtained barrier height is consistent with the theoretical one. The characteristic temperature ( T 0) resulting from the Cheung's functions [d V/d(ln I) vs. I and H( I) vs. I], is seen that there is good agreement between the T 0 values from both Cheung's functions. The relevant carrier transport mechanisms of Au/p-CZTS/n-type GaN HJ are explained based on the thermally decreased energy band gap of n-type GaN layers, thermally activated deep donors and increased further activated shallow donors.

Application of the Finite Elemental Analysis to Modeling Temperature Change of the Vaccine in an Insulated Packaging Container during Transport.

Science.gov (United States)

Ge, Changfeng; Cheng, Yujie; Shen, Yan

2013-01-01

This study demonstrated an attempt to predict temperatures of a perishable product such as vaccine inside an insulated packaging container during transport through finite element analysis (FEA) modeling. In order to use the standard FEA software for simulation, an equivalent heat conduction coefficient is proposed and calculated to describe the heat transfer of the air trapped inside the insulated packaging container. The three-dimensional, insulated packaging container is regarded as a combination of six panels, and the heat flow at each side panel is a one-dimension diffusion process. The transit-thermal analysis was applied to simulate the heat transition process from ambient environment to inside the container. Field measurements were carried out to collect the temperature during transport, and the collected data were compared to the FEA simulation results. Insulated packaging containers are used to transport temperature-sensitive products such as vaccine and other pharmaceutical products. The container is usually made of an extruded polystyrene foam filled with gel packs. World Health Organization guidelines recommend that all vaccines except oral polio vaccine be distributed in an environment where the temperature ranges between +2 to +8 °C. The primary areas of concern in designing the packaging for vaccine are how much of the foam thickness and gel packs should be used in order to keep the temperature in a desired range, and how to prevent the vaccine from exposure to freezing temperatures. This study uses numerical simulation to predict temperature change within an insulated packaging container in vaccine cold chain. It is our hope that this simulation will provide the vaccine industries with an alternative engineering tool to validate vaccine packaging and project thermal equilibrium within the insulated packaging container.

Relationships Between Temperament and Transportation With Rectal Temperature and Serum Concentrations of Cortisol and Epinephrine in Bulls

Science.gov (United States)

This study investigated whether temperament influences rectal temperature and serum concentrations of cortisol and epinephrine in response to transportation. Brahman bulls were selected based on temperament score (average of exit velocity, EV, and pen score, PS) measured 28 days prior to weaning wit...

Transport characteristics of Pd Schottky barrier diodes on epitaxial n-GaSb as determined from temperature dependent current–voltage measurements

Energy Technology Data Exchange (ETDEWEB)

Venter, A., E-mail: andre.venter@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Murape, D.M.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Auret, F.D. [Department of Physics, University of the Pretoria, Lynnwood Road, Pretoria 0002 (South Africa)

2015-01-01

The temperature dependent transport characteristics of Pd/n-GaSb:Te Schottky contacts with low and saturating reverse current are investigated by means of current–voltage measurements between 80 K and 320 K. The apparent barrier height and ideality factor increase with a decrease in temperature. Neither thermionic nor thermionic field emission can explain the low temperature characteristics of these diodes. Instead, evidence is presented for barrier inhomogeneity across the metal/semiconductor contact. A plot of the barrier height, ϕ{sub b} vs. 1/2kT revealed a double Gaussian distribution for the barrier height with ϕ{sub b,mean} assuming values of 0.59 eV ± 0.07 (80–140 K) and 0.25 eV ± 0.12 (140–320 K) respectively. - Highlights: • Transport characteristics of Pd/epitaxial n-GaSb:Te SBDs are studied by means of I-V-T measurements. • SBDs have remarkably low and saturating reverse current – of the lowest ever reported for GaSb. • Transport behaviour is explained by considering electronic states present on the GaSb surface. • Evidence is presented for barrier inhomogeneity across the metal-semiconductor contact.

Transport characteristics of Pd Schottky barrier diodes on epitaxial n-GaSb as determined from temperature dependent current–voltage measurements

International Nuclear Information System (INIS)

Venter, A.; Murape, D.M.; Botha, J.R.; Auret, F.D.

2015-01-01

The temperature dependent transport characteristics of Pd/n-GaSb:Te Schottky contacts with low and saturating reverse current are investigated by means of current–voltage measurements between 80 K and 320 K. The apparent barrier height and ideality factor increase with a decrease in temperature. Neither thermionic nor thermionic field emission can explain the low temperature characteristics of these diodes. Instead, evidence is presented for barrier inhomogeneity across the metal/semiconductor contact. A plot of the barrier height, ϕ b vs. 1/2kT revealed a double Gaussian distribution for the barrier height with ϕ b,mean assuming values of 0.59 eV ± 0.07 (80–140 K) and 0.25 eV ± 0.12 (140–320 K) respectively. - Highlights: • Transport characteristics of Pd/epitaxial n-GaSb:Te SBDs are studied by means of I-V-T measurements. • SBDs have remarkably low and saturating reverse current – of the lowest ever reported for GaSb. • Transport behaviour is explained by considering electronic states present on the GaSb surface. • Evidence is presented for barrier inhomogeneity across the metal-semiconductor contact

Temperature dependent dielectric properties and ion transportation in solid polymer electrolyte for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Sengwa, R. J., E-mail: rjsengwa@rediffmail.com; Dhatarwal, Priyanka, E-mail: dhatarwalpriyanka@gmail.com; Choudhary, Shobhna, E-mail: shobhnachoudhary@rediffmail.com [Dielectric Research Laboratory, Department of Physics, Jai Narain Vyas University, Jodhpur – 342 005 (India)

2016-05-06

Solid polymer electrolyte (SPE) film consisted of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) blend matrix with lithium tetrafluroborate (LiBF{sub 4}) as dopant ionic salt and poly(ethylene glycol) (PEG) as plasticizer has been prepared by solution casting method followed by melt pressing. Dielectric properties and ionic conductivity of the SPE film at different temperatures have been determined by dielectric relaxation spectroscopy. It has been observed that the dc ionic conductivity of the SPE film increases with increase of temperature and also the decrease of relaxation time. The temperature dependent relaxation time and ionic conductivity values of the electrolyte are governed by the Arrhenius relation. Correlation observed between dc conductivity and relaxation time confirms that ion transportation occurs with polymer chain segmental dynamics through hopping mechanism. The room temperature ionic conductivity is found to be 4 × 10{sup −6} S cm{sup −1} which suggests the suitability of the SPE film for rechargeable lithium batteries.

From boiling point to glass transition temperature: transport coefficients in molecular liquids follow three-parameter scaling.

Science.gov (United States)

Schmidtke, B; Petzold, N; Kahlau, R; Hofmann, M; Rössler, E A

2012-10-01

The phenomenon of the glass transition is an unresolved problem in condensed matter physics. Its prominent feature, the super-Arrhenius temperature dependence of the transport coefficients, remains a challenge to be described over the full temperature range. For a series of molecular glass formers, we combined τ(T) collected from dielectric spectroscopy and dynamic light scattering covering a range 10(-12) s < τ(T) < 10(2) s. Describing the dynamics in terms of an activation energy E(T), we distinguish a high-temperature regime characterized by an Arrhenius law with a constant activation energy E(∞) and a low-temperature regime for which E(coop)(T) ≡ E(T)-E(∞) increases exponentially while cooling. A scaling is introduced, specifically E(coop)(T)/E(∞) [proportionality] exp[-λ(T/T(A)-1)], where λ is a fragility parameter and T(A) a reference temperature proportional to E(∞). In order to describe τ(T) still the attempt time τ(∞) has to be specified. Thus, a single interaction parameter E(∞) describing the high-temperature regime together with λ controls the temperature dependence of low-temperature cooperative dynamics.

Degradation evaluation of high temperature pipeline material for power plant using ultrasonic noise analysis

International Nuclear Information System (INIS)

Lee, Sang Guk; Chung, Min Hwa; Cho, Yong Sang; Lee, In Cheol

2001-01-01

Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep and thermal fatigue damage due to severe operating conditions such as high temperature and high pressure for an extended period time. Conventional measurement techniques for measuring creep damage have such disadvantages as complex preparation and measurement procedures, too many control parameters. And also these techniques have low practicality and applied only to component surfaces with good accessibility. In this paper, artificial degradation test and ultrasonic measurement for their degraded specimens were carried out for the purpose of evaluation for creep and thermal fatigue damage. Absolute measuring method of quantitative ultrasonic measurement for material degradation was established, and long term creep/thermal fatigue degradation tests using life prediction formula were carried out. As a result of ultrasonic tests for crept and thermal fatigued specimens, we conformed that the ultrasonic noise linearly increased in proportion to the increase of degradation.

Temperature Data Evaluation

International Nuclear Information System (INIS)

Gillespie, David

2003-01-01

Groundwater temperature is sensitive to the competing processes of heat flow from below the advective transport of heat by groundwater flow. Because groundwater temperature is sensitive to conductive and advective processes, groundwater temperature may be utilized as a tracer to further constrain the uncertainty of predictions of advective radionuclide transport models constructed for the Nevada Test Site (NTS). Since heat transport, geochemical, and hydrologic models for a given area must all be consistent, uncertainty can be reduced by devaluing the weight of those models that do not match estimated heat flow. The objective of this study was to identify the quantity and quality of available heat flow data at the NTS. One-hundred-forty-five temperature logs from 63 boreholes were examined. Thirteen were found to have temperature profiles suitable for the determination of heat flow values from one or more intervals within the boreholes. If sufficient spatially distributed heat flow values are obtained, a heat transport model coupled to a hydrologic model may be used to reduce the uncertainty of a nonisothermal hydrologic model of the NTS

Temperature and press load stimulation on thermal transport in fibrous and porous composite insulators

International Nuclear Information System (INIS)

Rehman, M.A.; Maqsood, A.

2006-01-01

Thermal transport properties of synthetic pliable insulators are measured as a function of applied pressure at constant temperatures. Advantageous Transient Plane Source (ATPS) method is used for the simultaneous measurement of thermal conductivity and thermal diffusivity of these materials and heat capacity per unit volume is then calculated. Three samples namely foam, closed cell foam and fiber glass are subjected to press load, taking into account the flexibility and sustainability of the samples and the requirements of the technique used. The thermal data of the samples were determined within the temperature range (300-414K) and pressure range (Normal -15kPa). These materials are used for thermal insulation and temperature control of air-conditioned space, acoustic and sound insulation, agriculture and fishery, sports and leisure goods, building and civil engineering, industrial packaging cold storage ware house, boiler work and other electric appliances, so they are helpful in reducing energy losses. (author)

Trap density of states in n-channel organic transistors: variable temperature characteristics and band transport

International Nuclear Information System (INIS)

Cho, Joung-min; Akiyama, Yuto; Kakinuma, Tomoyuki; Mori, Takehiko

2013-01-01

We have investigated trap density of states (trap DOS) in n-channel organic field-effect transistors based on N,N ’-bis(cyclohexyl)naphthalene diimide (Cy-NDI) and dimethyldicyanoquinonediimine (DMDCNQI). A new method is proposed to extract trap DOS from the Arrhenius plot of the temperature-dependent transconductance. Double exponential trap DOS are observed, in which Cy-NDI has considerable deep states, by contrast, DMDCNQI has substantial tail states. In addition, numerical simulation of the transistor characteristics has been conducted by assuming an exponential trap distribution and the interface approximation. Temperature dependence of transfer characteristics are well reproduced only using several parameters, and the trap DOS obtained from the simulated characteristics are in good agreement with the assumed trap DOS, indicating that our analysis is self-consistent. Although the experimentally obtained Meyer-Neldel temperature is related to the trap distribution width, the simulation satisfies the Meyer-Neldel rule only very phenomenologically. The simulation also reveals that the subthreshold swing is not always a good indicator of the total trap amount, because it also largely depends on the trap distribution width. Finally, band transport is explored from the simulation having a small number of traps. A crossing point of the transfer curves and negative activation energy above a certain gate voltage are observed in the simulated characteristics, where the critical V G above which band transport is realized is determined by the sum of the trapped and free charge states below the conduction band edge

Heat Transport upon River-Water Infiltration investigated by Fiber-Optic High-Resolution Temperature Profiling

Science.gov (United States)

Vogt, T.; Schirmer, M.; Cirpka, O. A.

2010-12-01

Infiltrating river water is of high relevance for drinking water supply by river bank filtration as well as for riparian groundwater ecology. Quantifying flow patterns and velocities, however, is hampered by temporal and spatial variations of exchange fluxes. In recent years, heat has become a popular natural tracer to estimate exchange rates between rivers and groundwater. Nevertheless, field investigations are often limited by insufficient sensors spacing or simplifying assumptions such as one-dimensional flow. Our interest lies in a detailed local survey of river water infiltration at a restored river section at the losing river Thur in northeast Switzerland. Here, we measured three high-resolution temperature profiles along an assumed flow path by means of distributed temperature sensing (DTS) using fiber optic cables wrapped around poles. Moreover, piezometers were equipped with standard temperature sensors for a comparison to the DTS data. Diurnal temperature oscillations were tracked in the river bed and the riparian groundwater and analyzed by means of dynamic harmonic regression and subsequent modeling of heat transport with sinusoidal boundary conditions to quantify seepage velocities and thermal diffusivities. Compared to the standard temperature sensors, the DTS data give a higher vertical resolution, facilitating the detection of process- and structure-dependent patterns of the spatiotemporal temperature field. This advantage overcompensates the scatter in the data due to instrument noise. In particular, we could demonstrate the impact of heat conduction through the unsaturated zone on the riparian groundwater by the high resolution temperature profiles.

Metal temperature monitoring in corrosive gases at high temperature and high thermal flows; Monitoreo de temperaturas de metal en gases corrosivos a alta temperatura y altos flujos termicos

Energy Technology Data Exchange (ETDEWEB)

Huerta Espino, Mario; Martinez Flores, Marco Antonio; Martinez Villafane, Alberto; Porcayo Calderon, Jesus; Gomez Guzman, Roberto; Reyes Cervantes, Fernando [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1991-12-31

The direct measurement of metal temperatures during operation in superheater, reheater, and water wall tubes in zones exposed to high thermal flows is of great interest for the operation and analysis of the correct functioning of a steam generator. The operation temperature measurement of these zones differs very much of the monitored temperature in headers in the dead chamber, since the temperature measured in this zone is the steam temperature that does not reflect the one detected in the gas zone. For this reason, the thermocouples implant in gas zones will detect the real metal temperature and the incidence that some operation variables might have on it (Martinez et al., (1990). [Espanol] La medicion directa de temperaturas de metal durante operacion en tubos de sobrecalentador, recalentador y pared de agua en zonas expuestas a altos flujos termicos es de gran interes para la operacion y analisis del buen funcionamiento de un generador de vapor. La medicion de la temperatura de operacion de estas zonas, difiere mucho de la temperatura monitoreada en cabezales en zona de camara muerta, ya que la temperatura registrada en esta zona es la de vapor que no es un reflejo de la detectada en zona de gases. Por esta razon, la implantacion de termopares en zona de gases detectara la temperatura de metal real y la incidencia que algunas variables de operacion tengan sobre esta (Martinez et al., 1990).

Metal temperature monitoring in corrosive gases at high temperature and high thermal flows; Monitoreo de temperaturas de metal en gases corrosivos a alta temperatura y altos flujos termicos

Energy Technology Data Exchange (ETDEWEB)

Huerta Espino, Mario; Martinez Flores, Marco Antonio; Martinez Villafane, Alberto; Porcayo Calderon, Jesus; Gomez Guzman, Roberto; Reyes Cervantes, Fernando [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1990-12-31

The direct measurement of metal temperatures during operation in superheater, reheater, and water wall tubes in zones exposed to high thermal flows is of great interest for the operation and analysis of the correct functioning of a steam generator. The operation temperature measurement of these zones differs very much of the monitored temperature in headers in the dead chamber, since the temperature measured in this zone is the steam temperature that does not reflect the one detected in the gas zone. For this reason, the thermocouples implant in gas zones will detect the real metal temperature and the incidence that some operation variables might have on it (Martinez et al., (1990). [Espanol] La medicion directa de temperaturas de metal durante operacion en tubos de sobrecalentador, recalentador y pared de agua en zonas expuestas a altos flujos termicos es de gran interes para la operacion y analisis del buen funcionamiento de un generador de vapor. La medicion de la temperatura de operacion de estas zonas, difiere mucho de la temperatura monitoreada en cabezales en zona de camara muerta, ya que la temperatura registrada en esta zona es la de vapor que no es un reflejo de la detectada en zona de gases. Por esta razon, la implantacion de termopares en zona de gases detectara la temperatura de metal real y la incidencia que algunas variables de operacion tengan sobre esta (Martinez et al., 1990).

Method and apparatus for transport, introduction, atomization and excitation of emission spectrum for quantitative analysis of high temperature gas sample streams containing vapor and particulates without degradation of sample stream temperature

Science.gov (United States)

Eckels, David E.; Hass, William J.

1989-05-30

A sample transport, sample introduction, and flame excitation system for spectrometric analysis of high temperature gas streams which eliminates degradation of the sample stream by condensation losses.

Temperature Dependent Electron Transport Properties of Gold Nanoparticles and Composites: Scanning Tunneling Spectroscopy Investigations.

Science.gov (United States)

Patil, Sumati; Datar, Suwarna; Dharmadhikari, C V

2018-03-01

Scanning tunneling spectroscopy (STS) is used for investigating variations in electronic properties of gold nanoparticles (AuNPs) and its composite with urethane-methacrylate comb polymer (UMCP) as function of temperature. Films are prepared by drop casting AuNPs and UMCP in desired manner on silicon substrates. Samples are further analyzed for morphology under scanning electron microscopy (SEM) and atomic force microscopy (AFM). STS measurements performed in temperature range of 33 °C to 142 °C show systematic variation in current versus voltage (I-V) curves, exhibiting semiconducting to metallic transition/Schottky behavior for different samples, depending upon preparation method and as function of temperature. During current versus time (I-t) measurement for AuNPs, random telegraphic noise is observed at room temperature. Random switching of tunneling current between two discrete levels is observed for this sample. Power spectra derived from I-t show 1/f2 dependence. Statistical analysis of fluctuations shows exponential behavior with time width τ ≈ 7 ms. Local density of states (LDOS) plots derived from I-V curves of each sample show systematic shift in valance/conduction band edge towards/away from Fermi level, with respect to increase in temperature. Schottky emission is best fitted electron emission mechanism for all samples over certain range of bias voltage. Schottky plots are used to calculate barrier heights and temperature dependent measurements helped in measuring activation energies for electron transport in all samples.

Study of Exciton Hopping Transport in PbS Colloidal Quantum Dot Thin Films Using Frequency- and Temperature-Scanned Photocarrier Radiometry

Science.gov (United States)

Hu, Lilei; Mandelis, Andreas; Melnikov, Alexander; Lan, Xinzheng; Hoogland, Sjoerd; Sargent, Edward H.

2017-01-01

Solution-processed colloidal quantum dots (CQDs) are promising materials for realizing low-cost, large-area, and flexible photovoltaic devices. The study of charge carrier transport in quantum dot solids is essential for understanding energy conversion mechanisms. Recently, solution-processed two-layer oleic-acid-capped PbS CQD solar cells with one layer treated with tetrabutylammonium iodide (TBAI) serving as the main light-absorbing layer and the other treated with 1,2-ethanedithiol (EDT) acting as an electron-blocking/hole-extraction layer were reported. These solar cells demonstrated a significant improvement in power conversion efficiency of 8.55% and long-term air stability. Coupled with photocarrier radiometry measurements, this work used a new trap-state mediated exciton hopping transport model, specifically for CQD thin films, to unveil and quantify exciton transport mechanisms through the extraction of hopping transport parameters including exciton lifetimes, hopping diffusivity, exciton detrapping time, and trap-state density. It is shown that PbS-TBAI has higher trap-state density than PbS-EDT that results in higher PbS-EDT exciton lifetimes. Hopping diffusivities of both CQD thin film types show similar temperature dependence, particularly higher temperatures yield higher hopping diffusivity. The higher diffusivity of PbS-TBAI compared with PbS-EDT indicates that PbS-TBAI is a much better photovoltaic material than PbS-EDT. Furthermore, PCR temperature spectra and deep-level photothermal spectroscopy provided additional insights to CQD surface trap states: PbS-TBAI thin films exhibit a single dominant trap level, while PbS-EDT films with lower trap-state densities show multiple trap levels.

Ba doped Fe3O4 nanocrystals: Magnetic field and temperature tuning dielectric and electrical transport

Science.gov (United States)

Dutta, Papia; Mandal, S. K.; Nath, A.

2018-05-01

Nanocrystalline BaFe2O4 has been prepared through low temperature pyrophoric reaction method. The structural, dielectric and electrical transport properties of BaFe2O4 are investigated in detail. AC electrical properties have been studied over the wide range of frequencies with applied dc magnetic fields and temperatures. The value of impedance is found to increase with increase in magnetic field attributing the magnetostriction property of the sample. The observed value of magneto-impedance and magnetodielectric is found to ∼32% and ∼33% at room temperature. Nyquist plots have been fitted using resistance-capacitor circuits at different magnetic fields and temperatures showing the dominant role of grain and grain boundaries of the sample. Metal-semiconductor transition ∼403 K has been discussed in terms of delocalized and localized charge carrier.We have estimated activation energy using Arrhenius relation indicating temperature dependent electrical relaxation process in the system. Ac conductivity follow a Jonscher’s single power law indicating the large and small polaronic hopping conduction mechanism in the system.

Transport properties of silver telluride in the solid and liquid states; Etude des proprietes de transport dans le tellurure d'argent Ag{sub 2}Te aux hautes temperatures a l'etat solide et a l'etat liquide

Energy Technology Data Exchange (ETDEWEB)

Pham, N T [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-01-01

Measurements of the electrical resistivity, Hall coefficient and thermoelectric power have been carried out for silver telluride over a large temperature range including both solid and liquid states. The analysis of the experimental data shows that in the solid state the transport properties are governed by an ambipolar process with an electron mobility much higher than the hole mobility ({mu}{sub n} = 10*{mu}{sub p}). It is found that the temperature dependence of the electron mobility can be represented by a T{sup -3} law. Deviations from the stoichiometric composition Ag{sub 2}Te have been studied. For all specimens, melting is accompanied by discontinuous variations in the transport properties. Above the melting point, the magnitude of the measured parameters and their temperature dependence show that liquid silver telluride behaves as a semiconductor. The contribution of Ag{sup +} ions to transport phenomena is suggested to account for the behaviour of the electrical properties. Experimental data have been analysed in terms of conventional theories. (author) [French] Les mesures de la resistivite electrique, du coefficient de Hall et du pouvoir thermoelectrique ont ete effectuees sur le tellurure d'argent dans un large domaine de temperature couvrant l'etat solide et l'etat liquide. L'analyse des resultats experimentaux obtenus a l'etat solide montre que les proprietes de transport sont gouvernees par le processus ambipolaire avec une mobilite des electrons beaucoup plus grande que celle des trous ({mu}{sub n} 10*{mu}{sub p}). On trouve que la mobilite des electrons varie avec la temperature suivant la loi T{sup -3}. Les ecarts de la composition stoechiometrique Ag{sub 2}Te ont ete etudies. Pour tous les echantillons, la fusion est caracterisee par des variations discontinues des proprietes de transport. Au dessus du point de fusion, la grandeur des parametres mesures ainsi que leur variation avec la temperature montrent que le tellurure d'argent liquide se

High Temperature Superconducting Magnets with Active Control for Attraction Levitation Transport Applications

Science.gov (United States)

Jones, Harry; Jenkins, Richard G.; Goodall, Roger M.; Macleod, Colin; ElAbbar, Abdallah A.; Campbell, Archie M.

1996-01-01

A research program, involving 3 British universities, directed at quantifying the controllability of High Temperature Superconducting (HTS) magnets for use in attraction levitation transport systems will be described. The work includes measurement of loss mechanisms for iron cored HTS magnets which need to produce a flux density of approx. 1 tesla in the airgap between the magnet poles and a ferromagnetic rail. This flux density needs to be maintained and this is done by introducing small variations of the magnet current using a feedback loop, at frequencies up to 10 Hz to compensate for load changes, track variation etc. The test magnet assemblies constructed so far will be described and the studies and modelling of designs for a practical levitation demonstrator (using commercially obtained HTS tape) will be discussed with particular emphasis on how the field distribution and its components, e.g., the component vector normal to the broad face of the tape, can radically affect design philosophy compared to the classical electrical engineering approach. Although specifically aimed at levitation transport the controllability data obtained have implications for a much wider range of applications.

Transport in stellarators

International Nuclear Information System (INIS)

Maassberg, H.; Brakel, R.; Burhenn, R.; Gasparino, U.; Grigull, P.; Kick, M.; Kuehner, G.; Ringler, H.; Sardei, F.; Stroth, U.; Weller, A.

1993-01-01

The local electron and ion heat transport as well as the particle and impurity transport properties in stellarators are reviewed. In this context, neoclassical theory is used as a guideline for the comparison of the experimental results of the quite different confinement concepts. At sufficiently high temperatures depending on the specific magnetic configuration, neoclassical predictions are confirmed by experimental findings. The confinement properties in the LMFP collisionality regime are discussed with respect to the next stellarator generation, for which at higher temperatures the neoclassical transport is expected to become more important. (orig.)

Effect of the Temperature, External Magnetic Field, and Transport Current on Electrical Properties, Vortex Structure Evolution Processes, and Phase Transitions in Subsystems of Superconducting Grains and "Weak Links" of Granular Two-Level High-Temperature Superconductor YBa2Cu3O7-δ

Science.gov (United States)

Derevyanko, V. V.; Sukhareva, T. V.; Finkel', V. A.

2018-03-01

The temperature dependences of the resistivity of granular high-temperature superconductor YBa2Cu3O7-δ ρ( T) are measured at various transverse external magnetic fields 0 ≤ H ext ≤ 100 Oe in the temperature range from the resistivity onset temperature T ρ = 0 to the superconducting transition critical temperature T c at the transport current density from 50 to 2000 mA/cm2. The effect of the external magnetic field and transport current density on the kinetics of phase transitions in both subsystems of granular two-level HTSC ( T = T c2J, T c1g, T c ) is determined. The feasibility of the topological phase transition, i.e., the Berezinsky-Kosterlitz-Thouless transition, in the Josephson medium at T c2J < T BKT < T c1g "in transport current" is established, and its feasibility conditions are studied.

Transport and fluctuations in high temperature spheromak plasmas

International Nuclear Information System (INIS)

McLean, H.S.; Wood, R.D.; Cohen, B.I.; Hooper, E.B.; Hill, D.N.; Moller, J.M.; Romero-Talamas, C.; Woodruff, S.

2006-01-01

Higher electron temperature (T e >350 eV) and reduced electron thermal diffusivity (χ e 2 /s) is achieved in the Sustained Spheromak Physics Experiment (SSPX) by increasing the discharge current=I gun and gun bias flux=ψ gun in a prescribed manner. The internal current and q=safety factor profile derived from equilibrium reconstruction as well as the measured magnetic fluctuation amplitude can be controlled by programming the ratio λ gun =μ 0 I gun /ψ gun . Varying λ gun above and below the minimum energy eigenvalue=λ FC of the flux conserver (∇xB-vector=λ FC B-vector) varies the q profile and produces the m/n=poloidal/toroidal magnetic fluctuation mode spectrum expected from mode-rational surfaces with q=m/n. The highest T e is measured when the gun is driven with λ gun slightly less than λ FC , producing low fluctuation amplitudes ( e as T e increases, differing from Bohm or open field line transport models where χ e increases with T e . Detailed resistive magnetohydrodynamic simulations with the NIMROD code support the analysis of energy confinement in terms of the causal link with the q profile, magnetic fluctuations associated with low-order mode-rational surfaces, and the quality of magnetic surfaces

Electron-temperature-gradient-driven drift waves and anomalous electron energy transport

International Nuclear Information System (INIS)

Shukla, P.K.; Murtaza, G.; Weiland, J.

1990-01-01

By means of a kinetic description for ions and Braginskii's fluid model for electrons, three coupled nonlinear equations governing the dynamics of low-frequency short-wavelength electrostatic waves in the presence of equilibrium density temperature and magnetic-field gradients in a two-component magnetized plasma are derived. In the linear limit a dispersion relation that admits new instabilities of drift waves is presented. An estimate of the anomalous electron energy transport due to non-thermal drift waves is obtained by making use of the saturated wave potential, which is deduced from the mixing-length hypothesis. Stationary solutions of the nonlinear equations governing the interaction of linearly unstable drift waves are also presented. The relevance of this investigation to wave phenomena in space and laboratory plasmas is pointed out. (author)

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin

Science.gov (United States)

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Chad Webb, R.; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A.

2014-09-01

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or ‘epidermal’, photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

A minimization procedure for estimating the power deposition and heat transport from the temperature response to auxiliary power modulation

International Nuclear Information System (INIS)

Eester, Dirk van

2004-01-01

A method commonly used for determining where externally launched power is absorbed inside a tokamak plasma is to examine the temperature response to modulation of the launched power. Strictly speaking, this response merely provides a first good guess of the actual power deposition rather than the deposition profile itself: not only local heat sources but also heat losses and heat wave propagation affect the temperature response at a given position. Making use of this, at first sight non-desirable, effect modulation becomes a useful tool for conducting transport studies. In this paper a minimization method based on a simple conduction-convection model is proposed for deducing the power deposition and transport characteristics from the experimentally measured (electron) energy density response to a modulation of the auxiliary heating power. An L-mode JET example illustrates the potential of the technique

Transport losses in finisher pigs: impact of transport distance and season of the year

Directory of Open Access Journals (Sweden)

Eva Voslarova

2017-01-01

Full Text Available Objective The death of animals during transport for slaughter is a major factor indicating the level of welfare in transported animals. The aim of this study was to assess mortality related to the commercial transport of finisher pigs for slaughter in the Czech Republic. Methods The inspectors of the State Veterinary Administration of the Czech Republic recorded the numbers of finisher pigs transported to processing plants in the Czech Republic for slaughter and the mortality in these pigs in relation to transport in the period from 2009 to 2014. Results Our results show that the likelihood of death losses in transported pigs increases with increasing transport distance. The transport-related mortality ranged from 0.049% in pigs transported for distances below 50 km to 0.145% in pigs transported for distances exceeding 300 km. The impact of external air temperature on the transport-related mortality found in our study clearly shows that current transport practices fail to ensure the welfare of pigs transported under other than moderate weather. Particularly cold temperatures below −2°C were associated with increased death losses in winter transport. Conclusion Despite a decreasing trend in the mortality of finisher pigs transported for slaughter in Europe, our study suggests that current transport conditions are not efficient at ensuring the welfare of pigs during transport for longer distances and the protection of pigs against the negative impact of extreme ambient temperatures. Further research should focus on developing practical guidelines to improve the welfare of pigs in transit accordingly.

Potential wine ageing during transportation

Directory of Open Access Journals (Sweden)

Jung Rainer

2014-01-01

Full Text Available In a global world, wineries have to satisfy the demand of consumers who wish to drink high quality wines from countries all over the world. To fulfill this request wines have to be transported, crossing thereby great distances from the place of production to the consumer country. At the Institute of Enology of Hochschule Geisenheim University examinations with White-, Rosé- and Red-Wines of different origins which had been transported over longer distances within Europe (Portugal, France, Italy to Germany by trucks were carried out. Shipping of wines was simulated in a climatized cabinet to analyze the influence on wine quality during this way and conditions of transportation. Time and temperature profiles were based on real transport situtations which were recorded during shipping from Germany to Japan using data loggers. White, Rosé and Red wines were transported during 6 to 8 weeks and then were analytically and sensorically compared to those which were stored at a constant temperature of 15 ∘C. Besides the effect of temperature, the movements and vibrations encountered by the wines were also examined. Analytically wines were analyzed for general analytical parameters with Fourier-Transformation-Infrared-Spectroscopie (FTIR, Colour differences (Spectralphotometrie and free and total sulfuric acid with Flow-Injection-Analysis (FIA. Sensory examinations with a trained panel were performed in difference tests in form of rankings and triangular tests. Summarizing the results from the different tests it could be found that transportation had an influence on the potential ageing of wines depending on the wine matrix. Especially high and varying temperatures during transportations over a longer distance and time had negative influences on wine quality. Also the movement of wine at higher temperatures had showed a negative effect whereas transport at cool temperatures even below 0 ∘C did not influence wine characteristics. Sophisticated

Effects of a single dose of enrofloxacin on body temperature and tracheobronchial neutrophil count in healthy Thoroughbreds premedicated with interferon-α and undergoing long-distance transportation.

Science.gov (United States)

Tsuchiya, Takeru; Hobo, Seiji; Endo, Yoshiro; Narita, Shoichi; Sakamoto, Koji

2012-07-01

To evaluate effects of a single dose of enrofloxacin (5 mg/kg, IV) on body temperature and tracheobronchial neutrophil count in healthy Thoroughbreds premedicated with interferon-α and undergoing long-distance transportation. 32 healthy Thoroughbreds. All horses received interferon-α (0.5 U/kg, sublingually, q 24 h) as an immunologic stimulant for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive enrofloxacin (5 mg/kg, IV, once; enrofloxacin group) or saline (0.9% NaCl) solution (50 mL, IV, once; control group) ≤ 1 hour before being transported 1,210 km via commercial vans (duration, approx 26 hours). Before and after transportation, clinical examination, measurement of temperature per rectum, and hematologic analysis were performed for all horses; a tracheobronchial aspirate was collected for neutrophil quantification in 12 horses (6/group). Horses received antimicrobial treatment after transportation if deemed necessary by the attending clinician. No adverse effects were associated with treatment. After transportation, WBC count and serum amyloid A concentration in peripheral blood samples and neutrophil counts in tracheobronchial aspirates were significantly lower in horses of the enrofloxacin group than in untreated control horses. Fever (rectal temperature, ≥ 38.5°C) after transportation was detected in 3 of 16 enrofloxacin group horses and 9 of 16 control horses; additional antimicrobial treatment was required in 2 horses in the enrofloxacin group and 7 horses in the control group. In horses premedicated with interferon-α, enrofloxacin appeared to provide better protection against fever and lower respiratory tract inflammation than did saline solution.

The influence of defects on the transport properties of AgSbPb18Te20 prepared at high pressure and high temperature

International Nuclear Information System (INIS)

Wang Yi; Zhu Pinwen; Jiao Hujun; Chen Haiyong; Ma Yanming; Niu Yingli; Li Yingai; Zhang Lijun; Zhang Tiechen; Gao Chunxiao; Zou Guangtian

2007-01-01

We synthesized polycrystal AgSbPb 18 Te 20 by using the method of high pressure and high temperature, and found that the defects produced by high pressure and high temperature caused the changes of transport properties. X-ray diffraction patterns showed that the cell parameters did not change obviously with synthesis at high pressure, apart from a small fluctuation. The electrical resistivity first increased, and then decreased to one quarter of the original value, as the synthesis pressure changed from low to high. The Seebeck coefficient decreased with the increase of synthesis pressure, and then changed from positive to negative. High pressure and high temperature could cause AgSbPb 18 Te 20 to change from a p-type to n-type semiconductor, increase the carrier concentration at maximum by two orders of magnitude, and shift the infrared absorption edge to a higher energy range. All of these phenomena were regarded as showing that high pressure and high temperature favored the formation of certain defects which could change the band structure and thereby change the transport properties

Characterization of temperature-dependent carrier transport in disordered indium-tin-oxide/poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate)/polyfluorene/Ca/Al polymer structures

International Nuclear Information System (INIS)

Jiang, Joe-Air; Wang, Jen-Cheng; Fang, Chia-Hui; Wu, Ya-Fen; Teng, Jen-Wei; Chen, Yu-Ting; Fan, Ping-Lin; Nee, Tzer-En

2011-01-01

The temperature-dependent electrical characteristics of polyfluorene-based polymer structures over a temperature range from 200 to 300 K are systematically investigated in this study. Initially, using the definitions of the Berthelot-type model, it is found that the sample exhibits a higher Berthelot-type temperature T B with high driving voltage, indicating that carrier transport in a disordered system manifests Berthelot-type behaviors. The ideal current density-voltage curve for the polymer structures given the carrier transmit mechanism is further elucidated by taking into account the ohmic conduction, trap charge limited current, and Mott and Gurney model of space charge limited current. The proposed procedure is simple and can be used to characterize the material with reasonable accuracy. We also study the density of the traps H t , and the characteristic energy of the distribution E t to better understand the carrier-transport process in organic materials and structures.

Experimental constraints on transport

International Nuclear Information System (INIS)

Luce, T.C.; Petty, K.H.; Burrell, K.H.; Forest, C.B.; Gohil, P.; Groebner, R.J.; De Haas, J.C.M.; James, R.A.; Makowski, M.A.

1994-12-01

Characterization of the cross-field energy transport in magnetic confinement experiments in a manner applicable to the accurate assessment of future machine performance continues to be a challenging goal. Experimental results from the DIII-D tokamak in the areas of dimensionless scaling and non-diffusive transport represent progress toward this goal. Dimensionless scaling shows how beneficial the increase in machine size and magnetic field is for future devices. The experiments on DIII-D are the first to determine separately the electron and ion scaling with normalized gyroradius ρ * ; the electrons scale as expected from gyro-Bohm class theories, while the ions scale consistent with the Goldston empirical scaling. This result predicts an increase in transport relative to Bohm diffusion as ρ * decreases in future devices. The existence of distinct ρ * scalings for ions and electrons cautions against a physical interpretation of one-fluid or global analysis. The second class of experiments reported here are the first to demonstrate the existence of non-diffusive energy transport. Electron cyclotron heating was applied at the half radius; the electron temperature profile remains substantially peaked. Power balance analysis indicates that heat must flow in the direction of increasing temperature, which is inconsistent with purely diffusive transport. The dynamics of electron temperature perturbations indicate the presence in the heat flux of a term dependent on temperature rather than its gradient. These two observations strongly constrain the types of models which can be applied to cross-field heat transport

Temperature modulates the effects of ocean acidification on intestinal ion transport in Atlantic cod, Gadus morhua

Directory of Open Access Journals (Sweden)

Marian Yong-An Hu

2016-06-01

Full Text Available CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid–base regulatory machinery of Atlantic cod (Gadus morhua and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for four weeks to three CO2 levels (550, 1,200 and 2,200 μatm covering present and near-future natural variability, at optimum (10°C and summer maximum temperature (18°C, respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na+/K+-ATPase (NKA, Na+/H+-exchanger 3 (NHE3, Na+/HCO3- cotransporter (NBC1, pendrin-like Cl-/HCO3- exchanger (SLC26a6, V-type H+-ATPase subunit a (VHA and Cl- channel 3 (CLC3 in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal HCO3- secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood HCO3- levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans.

Effects of processing delay, temperature, and transport tube type on results of quantitative bacterial culture of canine urine.

Science.gov (United States)

Patterson, Carly A; Bishop, Micah A; Pack, Julie D; Cook, Audrey K; Lawhon, Sara D

2016-01-15

To determine the impact of processing delay, temperature, and transport tube type on results of quantitative bacterial culture (QBC) of canine urine. Diagnostic test evaluation. 60 mL of pooled urine from 4 dogs, divided into six 10-mL aliquots. Urine aliquots were spiked with bacteria from 1 of 6 independent Escherichia coli cultures to achieve a target bacterial concentration of 10(5) CFUs/mL. One milliliter from each aliquot was transferred into 5 silicone-coated clot tubes (SCTs) and 5 urine transport tubes (UTTs). Samples were stored at 4°C (39°F) and 25°C (77°F) for 0, 8, and 24 hours, and then standard QBCs were performed. Median bacterial concentration for urine samples stored in a UTT for 24 hours at 4°C was lower than that for samples stored in an SCT under the same conditions. Conversely, a substantial decrease in median bacterial concentration was identified for samples stored for 24 hours in an SCT at 25°C, compared with the median concentration for samples stored in a UTT under the same conditions. Median bacterial concentration in samples stored in an SCT at 25°C for 24 hours (275 CFUs/mL) was less than the cutoff typically used to define clinically important bacteriuria by use of urine samples obtained via cystocentesis (ie, > 1,000 CFUs/mL). Canine urine samples submitted for immediate QBC should be transported in plain sterile tubes such as SCTs. When prolonged (24-hour) storage at room temperature is anticipated, urine samples should be transported in UTTs.

A multi-scale approach of mechanical and transport properties of cementitious materials under rises of temperature

International Nuclear Information System (INIS)

Caratini, G.

2012-01-01

The modern industrial activities (storage of nuclear waste, geothermal wells, nuclear power plants,...) can submit cementitious materials to some extreme conditions, for example at temperatures above 200 C. This level of temperature will induce phenomena of dehydration in the cement paste, particularly impacting the CSH hydrates which led to the mechanical cohesion. The effects of these temperatures on the mechanical and transport properties have been the subject of this thesis.To understand these effects, we need to take into account the heterogeneous, porous, multi-scale aspects of these materials. To do this, micro-mechanics and homogenization tools based on the Eshelby problem's solution were used. Moreover, to support this multi-scale modeling, mechanical testing based on the theory of porous media were conducted. The measurements of modulus compressibility, permeability and porosity under confining pressure were used to investigate the mechanisms of degradation of these materials during thermal loads up to 400 C. (author)

Drone transportation of blood products.

Science.gov (United States)

Amukele, Timothy; Ness, Paul M; Tobian, Aaron A R; Boyd, Joan; Street, Jeff

2017-03-01

Small civilian unmanned aerial vehicles (drones) are a novel way to transport small goods. To the best of our knowledge there are no studies examining the impact of drone transport on blood products, describing approaches to maintaining temperature control, or component physical characteristics during drone transport. Six leukoreduced red blood cell (RBC) and six apheresis platelet (PLT) units were split using sterile techniques. The larger parent RBC and PLT units, as well as six unthawed plasma units frozen within 24 hours of collection (FP24), were placed in a cooler, attached to the drone, and flown for up to 26.5 minutes with temperature logging. Ambient temperatures during the experimental window ranged between -1 and 18°C across 2 days. The difference between the ambient and unit temperatures was approximately 20°C for PLT and FP24 units. After flight, the RBC parent units were centrifuged and visually checked for hemolysis; the PLTs were checked for changes in mean PLT volumes (MPVs), pH, and PLT count; and the frozen air bubbles on the back of the FP24 units were examined for any changes in size or shape, as evidence of thawing. There was no evidence of RBC hemolysis; no significant changes in PLT count, pH, or MPVs; and no changes in the FP24 bubbles. The temperature of all units was maintained during transport and flight. There was no adverse impact of drone transport on RBC, PLT, or FP24 units. These findings suggest that drone transportation systems are a viable option for the transportation of blood products. © 2016 AABB.

Steam drum level control studies of a natural circulation multi loop reactor

Energy Technology Data Exchange (ETDEWEB)

Kumar, Rajesh; Contractor, A.D.; Srivastava, Abhishek; Lele, H.G. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Safety Div.; Vaze, K.K. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Design and Development Group

2013-12-15

The proposed heavy water moderated and light water cooled pressure tube type boiling water reactor works on natural circulation at all power levels. It has parallel inter-connected loops with 452 boiling channels in the main heat transport system configuration. These multiple (four) interconnected loops influence the steam drum level control adversely through the common reactor inlet header. Alternate design studies made earlier for efficient control of SD levels have shown favorable results. This has lead to explore further the present scheme with the compartmentalization of CRIH into four compartments catering to four loops separately. The conventional 3-element level control has been found to be working satisfactorily. The interconnections between ECCS header and inlet header compartments have also increased the safety margin for various LOCA and design basis events. The paper deals with the SD level control aspects for this novel MHT configuration which has been analyzed for various PIEs (Postulated Initiating Events) and found to be satisfactory. (orig.)

Heat and momentum transport of ion internal transport barrier plasmas on Large Helical Device

International Nuclear Information System (INIS)

Nagaoka, K.; Ida, K.; Yoshinuma, M.

2010-11-01

The peaked ion-temperature profile with steep gradient so called ion internal transport barrier (ion ITB) was formed in the neutral beam heated plasmas on the Large Helical Device (LHD) and the high-ion-temperature regime of helical plasmas has been significantly extended. The ion thermal diffusivity in the ion ITB plasma decreases down to the neoclassical transport level. The heavy ion beam probe (HIBP) observed the smooth potential profile with negative radial electric field (ion root) in the core region where the ion thermal diffusivity decreases significantly. The large toroidal rotation was also observed in the ion ITB core and the transport of toroidal momentum was analyzed qualitatively. The decrease of momentum diffusivity with ion temperature increase was observed in the ion ITB core. The toroidal rotation driven by ion temperature gradient so called intrinsic rotation is also identified. (author)

Transport characteristics of n-ZnO/p-Si heterojunction as determined from temperature dependent current–voltage measurements

Energy Technology Data Exchange (ETDEWEB)

Djiokap, S.R. Tankio, E-mail: stive.tankiodjiokap@nmmu.ac.za; Urgessa, Z.N.; Mbulanga, C.M.; Venter, A.; Botha, J.R.

2016-01-01

Zinc oxide (ZnO) nanorods have been synthesized by a two-step chemical bath deposition process on silicon substrates having different dopant densities and orientations. Scanning electron microscopy and X-ray diffraction analysis reveal that the orientation of the Si substrate does not affect the orientation, distribution or crystallinity of the nanostructures. The electrical properties of the ZnO/Si heterojunction are also investigated by current–voltage (I–V) measurements. The ideality factor is found to be 2.6 at 295 K, indicating that complex current transport mechanisms are at play. Temperature dependent I–V characteristics have been used to determine the dominant transport mechanism. The experimental results suggest that in the low bias region the current is dominated by a trap assisted multi-step tunneling process.

Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

Energy Technology Data Exchange (ETDEWEB)

Gordillo-Vazquez, F J [Instituto de Astrofisica de Andalucia (IAA), CSIC, PO Box 3004, 18080 Granada (Spain); Donko, Z [Research Institute for Solid State Physics and Optics, H-1525 Budapest, PO Box, 49 (Hungary)

2009-08-15

A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, {approx}215 K (at 11 km) and {approx}198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N {<=} 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas

Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

International Nuclear Information System (INIS)

Gordillo-Vazquez, F J; Donko, Z

2009-01-01

A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, ∼215 K (at 11 km) and ∼198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N ≤ 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas temperature is only slightly

Facilitated transport ceramic membranes for high-temperature gas cleanup. Final report, February 1990--April 1994

Energy Technology Data Exchange (ETDEWEB)

Quinn, R.; Minford, E.; Damle, A.S.; Gangwal, S.K.; Hart, B.A.

1994-04-01

The objective of this program was to demonstrate the feasibility of developing high temperature, high pressure, facilitated transport ceramic membranes to control gaseous contaminants in Integrated Gasification Combined Cycle (IGCC) power generation systems. Meeting this objective requires that the contaminant gas H{sub 2}S be removed from an IGCC gas mixture without a substantial loss of the other gaseous components, specifically H{sub 2} and CH{sub 4}. As described above this requires consideration of other, nonconventional types of membranes. The solution evaluated in this program involved the use of facilitated transport membranes consisting of molten mixtures of alkali and alkaline earth carbonate salts immobilized in a microporous ceramic support. To accomplish this objective, Air Products and Chemicals, Inc., Golden Technologies Company Inc., and Research Triangle Institute worked together to develop and test high temperature facilitated membranes for the removal of H{sub 2}S from IGCC gas mixtures. Three basic experimental activities were pursued: (1) evaluation of the H{sub 2}S chemistry of a variety of alkali and alkaline earth carbonate salt mixtures; (2) development of microporous ceramic materials which were chemically and physically compatible with molten carbonate salt mixtures under IGCC conditions and which could function as a host to support a molten carbonate mixture and; (3) fabrication of molten carbonate/ceramic immobilized liquid membranes and evaluation of these membranes under conditions approximating those found in the intended application. Results of these activities are presented.

Concurrent aggregation and transport of graphene oxide in saturated porous media: Roles of temperature, cation type, and electrolyte concentration.

Science.gov (United States)

Wang, Mei; Gao, Bin; Tang, Deshan; Yu, Congrong

2018-04-01

Simultaneous aggregation and retention of nanoparticles can occur during their transport in porous media. In this work, the concurrent aggregation and transport of GO in saturated porous media were investigated under the conditions of different combinations of temperature, cation type (valence), and electrolyte concentration. Increasing temperature (6-24 °C) at a relatively high electrolyte concentration (i.e., 50 mM for Na + , 1 mM for Ca 2+ , 1.75 mM for Mg 2+ , and 0.03 and 0.05 mM for Al 3+ ) resulted in enhanced GO retention in the porous media. For instance, when the temperature increased from 6 to 24 °C, GO recovery rate decreased from 31.08% to 6.53% for 0.03 mM Al 3+ and from 27.11% to 0 for 0.05 mM Al 3+ . At the same temperature, increasing cation valence and electrolyte concentration also promoted GO retention. Although GO aggregation occurred in the electrolytes during the transport, the deposition mechanisms of GO retention in the media depended on cation type (valence). For 50 mM Na + , surface deposition via secondary minima was the dominant GO retention mechanism. For multivalent cation electrolytes, GO aggregation was rapid and thus other mechanisms such as physical straining and sedimentation also played important roles in controlling GO retention in the media. After passing through the columns, the GO particles in the effluents showed better stability with lower initial aggregation rates. This was probably because less stable GO particles with lower surface charge densities in the porewater were filtered by the porous media, resulting in more stable GO particle with higher surface charge densities in the effluents. An advection-dispersion-reaction model was applied to simulate GO breakthrough curves and the simulations matched all the experimental data well. Copyright © 2017 Elsevier Ltd. All rights reserved.

Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus

International Nuclear Information System (INIS)

Casati, Alessandro; Mantica, P.; Eester, D. van; Hawkes, N.; De Vries, P.; Imbeaux, F.; Joffrin, E.; Marinoni, A.; Ryter, F.; Salmi, A.; Tala, T.

2007-01-01

New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed

Temperature-mediated polymorphism in molecular crystals: The impact on crystal packing and charge transport

KAUST Repository

Stevens, Loah A.; Goetz, Katelyn P.; Fonari, Alexandr; Shu, Ying; Williamson, Rachel M.; Bredas, Jean-Luc; Coropceanu, Veaceslav P.; Jurchescu, Oana D.; Collis, Gavin E.

2015-01-01

We report a novel synthesis to ultra high purity 7,14-bis((trimethylsilyl)ethynyl)dibenzo[b,def]-chrysene (TMS-DBC) and the use of this material in the growth of single crystals by solution and vapor deposition techniques. We observe that the substrate temperature has a dramatic impact on the crystal growth, producing two distinct polymorphs of TMS-DBC; low temperature (LT) fine red needles and high temperature (HT) large yellow platelets. Single crystal X-ray crystallography confirms packing structures where the LT crystals form a 1D slipped-stack structure, while the HT crystals adopt a 2D brickwork motif. These polymorphs also represent a rare example where both are extremely stable and do not interconvert to the other crystal structure upon solvent or thermal annealing. Single crystal organic field-effect transistors of the LT and HT crystals show that the HT 2D brickwork motif produces hole mobilities as high as 2.1 cm2 V-1 s-1, while the mobility of the 1D structure is significantly lower, at 0.028 cm2 V-1 s-1. Electronic-structure calculations indicate that the superior charge transport in the brickwork polymorph in comparison to the slipped-stack polymorph is due to the presence of an increased dimensionality of the charge migration pathways.

Temperature-mediated polymorphism in molecular crystals: The impact on crystal packing and charge transport

KAUST Repository

Stevens, Loah A.

2015-01-13

We report a novel synthesis to ultra high purity 7,14-bis((trimethylsilyl)ethynyl)dibenzo[b,def]-chrysene (TMS-DBC) and the use of this material in the growth of single crystals by solution and vapor deposition techniques. We observe that the substrate temperature has a dramatic impact on the crystal growth, producing two distinct polymorphs of TMS-DBC; low temperature (LT) fine red needles and high temperature (HT) large yellow platelets. Single crystal X-ray crystallography confirms packing structures where the LT crystals form a 1D slipped-stack structure, while the HT crystals adopt a 2D brickwork motif. These polymorphs also represent a rare example where both are extremely stable and do not interconvert to the other crystal structure upon solvent or thermal annealing. Single crystal organic field-effect transistors of the LT and HT crystals show that the HT 2D brickwork motif produces hole mobilities as high as 2.1 cm2 V-1 s-1, while the mobility of the 1D structure is significantly lower, at 0.028 cm2 V-1 s-1. Electronic-structure calculations indicate that the superior charge transport in the brickwork polymorph in comparison to the slipped-stack polymorph is due to the presence of an increased dimensionality of the charge migration pathways.

Temperature effect in potassium and nitrate ions in soil transport Efeito da temperatura no transporte dos íons potássio e nitrato no solo

Directory of Open Access Journals (Sweden)

Adriano D. M. A. Gonçalves

2008-09-01

Full Text Available When doing researches on solute dynamics in porous medium, the knowledge of medium characteristics and percolating liquids, as well as of external factors is very important. An important external factor is temperature and, in this sense, our purpose was determining potassium and nitrate transport parameters for different values of temperature, in miscible displacement experiments. Evaluated parameters were retardation factor (R, diffusion/dispersion coefficient (D and dispersivity, at ambient temperature (25 up to 28 ºC, 40 ºC and 50 ºC. Salts used were potassium nitrate and potassium chlorate, prepared in a solution made up of 5 ppm nitrate and 2.000 ppm potassium, with Red-Yellow Latosol porous medium. Temperature exhibited a positive influence upon porous medium solution and upon dispersion coefficient.No estudo da dinâmica de solutos num meio poroso, é de suma importância o conhecimento das propriedades do meio e dos líquidos percolantes, bem como de fatores externos. Um fator externo relevante é a temperatura e, nesse sentido, teve-se como objetivo determinar os parâmetros de transporte dos íons potássio e nitrato para diferentes valores de temperatura em experimentos de deslocamento miscível. Os parâmetros avaliados foram o fator de retardamento (R, o coeficiente de difusão/dispersão (D e a dispersividade (λ , e as temperaturas utilizadas foram a ambiente (25 a 28 ºC, 40 ºC e 50 ºC. Os sais utilizados foram nitrato de potássio e cloreto de potássio, preparados em solução composta de 50 ppm de nitrato e 2.000 ppm de potássio, sendo o meio poroso um Latossolo Vermelho-Amarelo, textura média. A temperatura apresentou influência positiva na velocidade da solução no meio poroso e no coeficiente de dispersão.

Temperature dependence of the transport properties of spin field-effect transistors built with InAs and Si channels

Science.gov (United States)

Osintsev, D.; Sverdlov, V.; Stanojević, Z.; Makarov, A.; Selberherr, S.

2012-05-01

We study the transport properties of the Datta-Das spin field-effect transistor built on InAs and Si. First, we demonstrate that the amplitude of the magnetoresistance oscillations as a function of the band mismatch between the ferromagnetic contacts and the semiconductor channel made of InAs decreases dramatically with increasing temperature. A shorter InAs channel is needed to create an InAs-based SpinFET which will operate at higher temperatures. Second, we show that the [1 0 0] orientation of the fin is preferable for silicon SpinFETs due to stronger modulation of the conductance as a function of spin-orbit interaction and magnetic field. Short silicon fins can be used for current modulation as a function of the conduction band mismatch between the channel and the ferromagnetic contacts only at relatively low temperatures. In contrast, longer silicon channels allow a TMR modulation at room temperature by changing the strength of the spin-orbit interaction through the gate bias.

Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

KAUST Repository

Zhao, Kui; Ngongang Ndjawa, Guy Olivier; Jagadamma, Lethy Krishnan; El Labban, Abdulrahman; Hu, Hanlin; Wang, Qingxiao; Li, Ruipeng; Abdelsamie, Maged; Beaujuge, Pierre; Amassian, Aram

2015-01-01

Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

KAUST Repository

Zhao, Kui

2015-07-30

Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn4N epitaxial thin film

International Nuclear Information System (INIS)

Shen, Xi; Shigematsu, Kei; Chikamatsu, Akira; Fukumura, Tomoteru; Hirose, Yasushi; Hasegawa, Tetsuya

2014-01-01

We report the electrical transport properties of ferrimagnetic Mn 4 N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn 4 N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m 3 , which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow

Energy Technology Data Exchange (ETDEWEB)

Gu, W.B.; Jungst, Rudolph G.; Nagasubramanian, Ganesan; Wang, C.Y.; Weidner, John.

1999-06-11

A two-dimensional model is developed to simulate discharge of a lithium/thionyl chloride primary battery. The model accounts for not only transport of species and charge, but also the electrode porosity variations and the electrolyte flow induced by the volume reduction caused by electrochemical reactions. Numerical simulations are performed using a finite volume method of computational fluid dynamics. The predicted discharge curves for various temperatures are compared to the experimental data with excellent agreement. Moreover, the simulation results. in conjunction with computer visualization and animation techniques, confirm that cell utilization in the temperature and current range of interest is limited by pore plugging or clogging of the front side of the cathode as a result of LiCl precipitation. The detailed two-dimensional flow simulation also shows that the electrolyte is replenished from the cell header predominantly through the separator into the front of the cathode during most parts of the discharge, especially for higher cell temperatures.

Nanostructures study of CNT nanofluids transport with temperature-dependent variable viscosity in a muscular tube

Science.gov (United States)

Akbar, Noreen Sher; Abid, Syed Ali; Tripathi, Dharmendra; Mir, Nazir Ahmed

2017-03-01

The transport of single-wall carbon nanotube (CNT) nanofluids with temperature-dependent variable viscosity is analyzed by peristaltically driven flow. The main flow problem has been modeled using cylindrical coordinates and flow equations are simplified to ordinary differential equations using long wavelength and low Reynolds' number approximation. Analytical solutions have been obtained for axial velocity, pressure gradient and temperature. Results acquired are discussed graphically for better understanding. It is observed that with an increment in the Grashof number the velocity of the governing fluids starts to decrease significantly and the pressure gradient is higher for pure water as compared to single-walled carbon nanotubes due to low density. As the specific heat is very high for pure water as compared to the multi-wall carbon nanotubes, it raises temperature of the muscles, in the case of pure water, as compared to the multi-walled carbon nanotubes. Furthermore, it is noticed that the trapped bolus starts decreasing in size as the buoyancy forces are dominant as compared to viscous forces. This model may be applicable in biomedical engineering and nanotechnology to design the biomedical devices.

SARTEMP2 - A computer program to calculate power and temperatures in a transport flask during a criticality accident

International Nuclear Information System (INIS)

Shaw, P.M.

1983-04-01

The computer code SARTEMP2, an extended version of the original SARTEMP program, which calculates the power and temperatures in a transport flask during a hypothetical criticality accident is described. The accident arises, it is assumed, during the refilling of the flask with water, bringing the system to delayed critical. As the water level continues to rise, reactivity is added causing the power to rise, and thus temperatures in the fuel, clad and water to increase. The point kinetics equations are coupled to the one-dimensional heat conduction equation. The model used, the method of solution of the equations and the input data required are given. (author)

Telematics for hazardous goods transportation; Anwendungen fuer den Transport von kritischen Guetern

Energy Technology Data Exchange (ETDEWEB)

Stingl, D [Danzas Logistics GmbH, Hamburg (Germany)

1999-07-01

In the course of the integration of the customer Langnese Iglo in autumn 1997 and in view of the already existing general conditions for the implementation of the equlations of the directive on food hygiene (HACCP-concept) as well as the permanently in reasing demand for quality of logistics DANZAS Logistics GmbH, cooperating closely with in deep-frozen goods customer Langnese-Iglo decided to develop a new system of quality assurance for the transportation of deep-frozen goods and apply this system to all its activities. First ideas about standard demands, technical solutions and multi-functional design showed that the project had to be handled in such a flexible way that temperature controlling (for the transportation of deep-frozen goods, temperature-controlled DANZAS-warehouses and all future temperature-controlled transportation) and the monitoring of security-relevant transportation can be integrated in one and the same project. (orig.) [German] Im Zuge der Integration des Kunden Langnese Iglo im Herbst 1997 und unter Beruecksichtigung der bereits vorliegenden Rahmenbedingungen zur Umsetzung der Bestimmungen der Lebensmittelhygieneverordnung (HACCP-Konzept) sowie des staendig wachsenden Qualitaetsanspruches an logistische Dienstleistungen, hat sich die DANZAS Logistics GmbH in enger Zusammenarbeit mit dem TK-Kunden Langnese Iglo entschlossen, ein innovatives System zur Qualitaetssicherung im Tiefkuehltransport zu erarbeiten und flaechendeckend einzusetzen. Die ersten Gedanken bezueglich Standardanforderungen, technischer Loesungsansaetze und multifunktionaler Ausrichtung zeigten, dass dieses Projekt so variabel zu gestalten ist, dass sowohl Temperaturcontrolling (fuer TK-Transporte, fuer die temperaturgefuehrten DANZAS-Laeger und zukuenftig alle temperaturgefuehrten Transporte) als auch die Ueberwachung sicherheitsrelevanter Transporte zu integrieren sind. (orig.)

Charge and spin transport in mesoscopic superconductors

Directory of Open Access Journals (Sweden)

M. J. Wolf

2014-02-01

Full Text Available Background: Non-equilibrium charge transport in superconductors has been investigated intensely in the 1970s and 1980s, mostly in the vicinity of the critical temperature. Much less attention has been paid to low temperatures and the role of the quasiparticle spin.Results: We report here on nonlocal transport in superconductor hybrid structures at very low temperatures. By comparing the nonlocal conductance obtained by using ferromagnetic and normal-metal detectors, we discriminate charge and spin degrees of freedom. We observe spin injection and long-range transport of pure, chargeless spin currents in the regime of large Zeeman splitting. We elucidate charge and spin transport by comparison to theoretical models.Conclusion: The observed long-range chargeless spin transport opens a new path to manipulate and utilize the quasiparticle spin in superconductor nanostructures.

High field electron-spin transport and observation of the Dyakonov-Perel spin relaxation of drifting electrons in low temperature-grown gallium arsenide

International Nuclear Information System (INIS)

Miah, M. Idrish

2008-01-01

High field electron-spin transport in low temperature-grown gallium arsenide is studied. We generate electron spins in the samples by optical pumping. During transport, we observe the Dyakonov-Perel (DP) [M.I. Dyakonov, V.I. Perel, Zh. Eksp. Teor. Fiz. 60 (1971) 1954] spin relaxation of the drifting electrons. The results are discussed and are compared with those obtained in calculations of the DP spin relaxation frequency of the hot electrons. A good agreement is obtained

High field electron-spin transport and observation of the Dyakonov-Perel spin relaxation of drifting electrons in low temperature-grown gallium arsenide

Energy Technology Data Exchange (ETDEWEB)

Miah, M. Idrish [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong-4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

2008-11-17

High field electron-spin transport in low temperature-grown gallium arsenide is studied. We generate electron spins in the samples by optical pumping. During transport, we observe the Dyakonov-Perel (DP) [M.I. Dyakonov, V.I. Perel, Zh. Eksp. Teor. Fiz. 60 (1971) 1954] spin relaxation of the drifting electrons. The results are discussed and are compared with those obtained in calculations of the DP spin relaxation frequency of the hot electrons. A good agreement is obtained.

Sediment transport via needle ice: a new method for diffusive transport on laboratory-scale hillslopes

Science.gov (United States)

Sweeney, K. E.; Roering, J. J.; Rempel, A. W.

2012-12-01

Convex hilltops formed by diffusive sediment transport are a fundamental feature of soil-mantled landscapes worldwide. Additionally, the competition and interaction between hillslopes and valleys control basic topographic metrics, such as relief, drainage density, and breaks in slope-area scaling. Despite recent progress in erosive landscape experiments, no published work has explored the competition of hillslope diffusion and channel advection experimentally. Here, we present preliminary findings on the plausibility of needle ice driven frost creep as a mechanism for laboratory hillslope transport of wet sediment. In nature, needle ice is a diurnal form of ice segregation, whereby liquid water held in sediment pore space is driven upward toward a near-surface freezing front by a temperature-controlled liquid pressure gradient. As needles grow perpendicular to the surface, sediment is incorporated in the growing needle ice by temperature perturbations and associated downward shifts in the freezing front. Sediment then moves downslope due to melting or sublimation of the ice needles. We constructed a slope of saturated sediment in a freezer to constrain the temperature, grain size, and soil moisture limits on laboratory needle ice growth and sediment transport. Surficial sediment transport is measured during experimentation by tracking the movement of colored grains. Additionally, at the end of each run we measure depth-dependent sediment transport by taking slices of the experimental slope and observing the displacement of buried columns of colored grains. In agreement with past work, we find that with temperatures just below freezing, soil moisture above 35%, and silt-sized sediment, the moisture migration induced by freezing releases enough latent heat to maintain the location of the freezing front and encourage needle ice growth. Our experiments demonstrate that the amount of sediment incorporated during needle growth, i.e., the transport efficiency, can be

Design of Annular Linear Induction Pump for High Temperature Liquid Lead Transportation

Energy Technology Data Exchange (ETDEWEB)

Kwak, Jae Sik; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2014-05-15

EM(Electro Magnetic) Pump is divided into two parts, which consisted of the primary one with electromagnetic core and exciting coils, and secondary one with liquid lead flow. The main geometrical variables of the pump included core length, inner diameter and flow gap while the electromagnetic ones covered pole pitch, turns of coil, number of pole pairs, input current and input frequency. The characteristics of design variables are analyzed by electrical equivalent circuit method taking into account hydraulic head loss in the narrow annular channel of the ALIP. The design program, which was composed by using MATLAB language, was developed to draw pump design variables according to input requirements of the flow rate, developing pressure and operation temperature from the analyses. The analysis on the design of ALIP for high temperature liquid lead transportation was carried for the produce of ALIP designing program based on MATLAB. By the using of ALIP designing program, we don't have to bother about geometrical relationship between each component during detail designing process because code calculate automatically. And prediction of outputs about designing pump can be done easily before manufacturing. By running the code, we also observe and analysis change of outputs caused by changing of pump factors. It will be helpful for the research about optimization of pump outputs.

Stratospheric temperatures and tracer transport in a nudged 4-year middle atmosphere GCM simulation

Science.gov (United States)

van Aalst, M. K.; Lelieveld, J.; Steil, B.; Brühl, C.; Jöckel, P.; Giorgetta, M. A.; Roelofs, G.-J.

2005-02-01

We have performed a 4-year simulation with the Middle Atmosphere General Circulation Model MAECHAM5/MESSy, while slightly nudging the model's meteorology in the free troposphere (below 113 hPa) towards ECMWF analyses. We show that the nudging 5 technique, which leaves the middle atmosphere almost entirely free, enables comparisons with synoptic observations. The model successfully reproduces many specific features of the interannual variability, including details of the Antarctic vortex structure. In the Arctic, the model captures general features of the interannual variability, but falls short in reproducing the timing of sudden stratospheric warmings. A 10 detailed comparison of the nudged model simulations with ECMWF data shows that the model simulates realistic stratospheric temperature distributions and variabilities, including the temperature minima in the Antarctic vortex. Some small (a few K) model biases were also identified, including a summer cold bias at both poles, and a general cold bias in the lower stratosphere, most pronounced in midlatitudes. A comparison 15 of tracer distributions with HALOE observations shows that the model successfully reproduces specific aspects of the instantaneous circulation. The main tracer transport deficiencies occur in the polar lowermost stratosphere. These are related to the tropopause altitude as well as the tracer advection scheme and model resolution. The additional nudging of equatorial zonal winds, forcing the quasi-biennial oscillation, sig20 nificantly improves stratospheric temperatures and tracer distributions.

Computer simulation of radial transport in tandem mirror machines

International Nuclear Information System (INIS)

Gilmore, J.M.

1979-01-01

A code used for simulation of classical radial transport in the 2XIIB experiment has been modified to simulate radial transport in TMX. Results have been obtained using classical transport coefficients and also using very simple trial neoclassical resonant transport coefficients. Comparison of the results obtained with solely classical transport and with both classical and neo-classical transport indicate that neoclassical transport depresses the ion density by approximately 5%. The central cell ion temperature is increased by approximately by the neo-classical transport, as is the electron temperature

The hotline in the grid. Higher temperatures with overhead lines can help to transport additional electricity; Der heisse Draht im Netz. Hoehere Temperaturen bei Freileitungen koennen helfen, Stromueberschuesse zu transportieren

Energy Technology Data Exchange (ETDEWEB)

Michels, Andreas; Friedrich, Uwe

2016-11-01

The electricity grid that has been used for decades reaches its limits when transporting increasing amounts of electricity over long distances. There are already limiting bottlenecks. One way to integrate more wind and solar power into the grid is provided by overhead lines with a higher maximum temperature. These can transport more electricity, enabling grid congestion to be avoided. One problem, though, is that metals expand more at high temperatures. As a result the line lengthens and sags more. However, special high-temperature conductors can provide a remedy here.

Temperature-tunable wettability on a bioinspired structured graphene surface for fog collection and unidirectional transport.

Science.gov (United States)

Song, Yun-Yun; Liu, Yan; Jiang, Hao-Bo; Li, Shu-Yi; Kaya, Cigdem; Stegmaier, Thomas; Han, Zhi-Wu; Ren, Lu-Quan

2018-02-22

We designed a type of smart bioinspired wettable surface with tip-shaped patterns by combining polydimethylsiloxane (PDMS) and graphene (PDMS/G). The laser etched porous graphene surface can produce an obvious wettability change between 200 °C and 0 °C due to a change in aperture size and chemical components. We demonstrate that the cooperation of the geometrical structure and the controllable wettability play an important role in water gathering, and surfaces with tip-shaped wettability patterns can quickly drive tiny water droplets toward more wettable regions, so making a great contribution to the improvement of water collection efficiency. In addition, due to the effective cooperation between super hydrophobic and hydrophilic regions of the special tip-shaped pattern, unidirectional water transport on the 200 °C heated PDMS/G surface can be realized. This study offers a novel insight into the design of temperature-tunable materials with interphase wettability that may enhance fog collection efficiency in engineering liquid harvesting equipment, and realize unidirectional liquid transport, which could potentially be applied to the realms of microfluidics, medical devices and condenser design.

Effects of sintering temperature on structural and electrical transport properties of zinc ferrites prepared by sol-gel route

International Nuclear Information System (INIS)

Anis-ur-Rehman, M.; Malik, M.A.; Ahmad, I.; Nasir, S.; Mubeen, M.; Abdullah, A.

2011-01-01

The effects of sintering temperature on the structural and electrical transport properties of nanocrystalline zinc ferrites are reported. The zinc ferrites were prepared by WOWS sol-gel synthesis route. The prepared sample was sintered at temperatures 500 deg. C, 700 deg. C and 900 deg. C respectively for 2 h. X-ray Diffraction (XRD) technique was used to describe the structural properties. The crystallite size, lattice parameters and porosity of samples were measured from the analysis of XRD data. The average crystallite size for each sample was measured using the Scherrer formula by considering the most intense (3 1 1) peak. The dielectric constant (e), dielectric loss tangent (tan theta ) and AC electrical conductivity of nanocrystalline Zn ferrites are investigated as a function of frequency and sintering temperature. All the electrical properties are explained in accordance with MaxwellWagner model and Koops phenomenological theory. (author)

Metallic transport and large anomalous Hall effect at room temperature in ferrimagnetic Mn{sub 4}N epitaxial thin film

Energy Technology Data Exchange (ETDEWEB)

Shen, Xi; Shigematsu, Kei [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp; Fukumura, Tomoteru [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Hirose, Yasushi; Hasegawa, Tetsuya [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan)

2014-08-18

We report the electrical transport properties of ferrimagnetic Mn{sub 4}N (001) epitaxial thin films grown by pulsed laser deposition on MgO (001) substrates. The Mn{sub 4}N thin films were tetragonally distorted with a ratio of out-of-plane to in-plane lattice constants of 0.987 and showed perpendicular magnetic anisotropy with an effective magnetic anisotropy constant of 0.16 MJ/m{sup 3}, which is comparable with that of a recently reported molecular-beam-epitaxy-grown film. The thin films exhibited metallic transport with a room temperature resistivity of 125 μΩ cm in addition to a large anomalous Hall effect with a Hall angle tangent of 0.023.

A worked example using the SP249 advanced assessment route: the carregado unit 6 final superheater outlet header

Energy Technology Data Exchange (ETDEWEB)

Brear, J.M.; Jarvis, P.; Jones, G.T. [ERA Technology (United Kingdom); Jovanovic, A.S.; Friemann, M.; Kluttig, B.; Ober, M. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt; Batista, A. [EDP-PROET (Portugal); Araujo, C.L. de; Pires, A. [ISQ (Portugal)

1995-12-31

As a key part of its information resource, the SP249 Project contains a number of case studies, drawn from the collective experience of the partners and from the literature. The user of the system may search this data-base by component type and material or by assessment method, to find a practical example close to his own current problem. He can thus draw upon past experience as well as state-of-the-art knowledge to obtain advice. To facilitate this, a set of key-words has been defined to create links between the case studies and the overall assessment methodology. These relate to damage and failure types and causes as well as to techniques of investigation and assessment. For demonstration, validation and didactic purposes, certain of these case studies - one per end-user utility in the project - have been chosen for full elaboration as `worked-examples`. These real component evaluations are worked through by an expert group from the project team so as to provide the utility staff with `hands-on` training in both the practical techniques of component life. The assessment and the use of the knowledge based system. The exercise also provides valuable opportunity for feedback, allowing refinement of the technology package and the software. Amongst these worked examples, an assessment of EDP`s Carregado Unit 6 Final Superheater Outlet Header has been chosen for special attention - as the operators have kindly allowed direct CSS to the component during two outages. This article summarises the Carregado Case Study. It is intended to serve as a demonstration and as to how the Advanced Assessment Route (AAR) is used in practice. The actions performed and results obtained are summarised

A simple Boltzmann transport equation for ballistic to diffusive transient heat transport

International Nuclear Information System (INIS)

Maassen, Jesse; Lundstrom, Mark

2015-01-01

Developing simplified, but accurate, theoretical approaches to treat heat transport on all length and time scales is needed to further enable scientific insight and technology innovation. Using a simplified form of the Boltzmann transport equation (BTE), originally developed for electron transport, we demonstrate how ballistic phonon effects and finite-velocity propagation are easily and naturally captured. We show how this approach compares well to the phonon BTE, and readily handles a full phonon dispersion and energy-dependent mean-free-path. This study of transient heat transport shows (i) how fundamental temperature jumps at the contacts depend simply on the ballistic thermal resistance, (ii) that phonon transport at early times approach the ballistic limit in samples of any length, and (iii) perceived reductions in heat conduction, when ballistic effects are present, originate from reductions in temperature gradient. Importantly, this framework can be recast exactly as the Cattaneo and hyperbolic heat equations, and we discuss how the key to capturing ballistic heat effects is to use the correct physical boundary conditions

Determination of Transport Properties From Flowing Fluid Temperature Logging In Unsaturated Fractured Rocks: Theory And Semi-Analytical Solution

International Nuclear Information System (INIS)

Mukhopadhyay, Sumit; Tsang, Yvonne W.

2008-01-01

Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper (Mukhopadhyay et al., 2008), we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks

Aerobic scope and cardiovascular oxygen transport is not compromised at high temperatures in the toad Rhinella marina.

Science.gov (United States)

Overgaard, Johannes; Andersen, Jonas L; Findsen, Anders; Pedersen, Pil B M; Hansen, Kasper; Ozolina, Karlina; Wang, Tobias

2012-10-15

Numerous recent studies convincingly correlate the upper thermal tolerance limit of aquatic ectothermic animals to reduced aerobic scope, and ascribe the decline in aerobic scope to failure of the cardiovascular system at high temperatures. In the present study we investigate whether this 'aerobic scope model' applies to an air-breathing and semi-terrestrial vertebrate Rhinella marina (formerly Bufo marinus). To quantify aerobic scope, we measured resting and maximal rate of oxygen consumption at temperatures ranging from 10 to 40°C. To include potential effects of acclimation, three groups of toads were acclimated chronically at 20, 25 and 30°C, respectively. The absolute difference between resting and maximal rate of oxygen consumption increased progressively with temperature and there was no significant decrease in aerobic scope, even at temperature immediately below the lethal limit (41-42°C). Haematological and cardiorespiratory variables were measured at rest and immediately after maximal activity at benign (30°C) and critically high (40°C) temperatures. Within this temperature interval, both resting and active heart rate increased, and there was no indication of respiratory failure, judged from high arterial oxygen saturation, P(O2) and [Hb(O2)]. With the exception of elevated resting metabolic rate for cold-acclimated toads, we found few differences in the thermal responses between acclimation groups with regard to the cardiometabolic parameters. In conclusion, we found no evidence for temperature-induced cardiorespiratory failure in R. marina, indicating that maintenance of aerobic scope and oxygen transport is unrelated to the upper thermal limit of this air-breathing semi-terrestrial vertebrate.

Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Liu, Xinke, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com; He, Jiazhu; Tang, Dan; Lu, Youming; Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun [College of Materials Science and Engineering, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Nanshan District Key Lab for Biopolymer and Safety Evaluation, Shenzhen University, 3688 Nanhai Ave, Shenzhen 518060 (China); Liu, Qiang; Wen, Jiao; Yu, Wenjie [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Chang Ning Road, Shanghai 200050 (China); Liu, Wenjun [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 220 Handan Road, Shanghai 200433 (China); Wu, Jing, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com [Department of Physics, National University of Singapore, 21 Lower Kent Ridge Road, 117576 Singapore (Singapore); He, Zhubing [Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Shenzhen 518055 (China); Ang, Kah-Wee [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore (Singapore)

2015-09-28

Large size monolayer Molybdenum disulphide (MoS{sub 2}) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS{sub 2} field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm{sup 2}V{sup −1}s{sup −1} was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS{sub 2} FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature.

Phonon transport across nano-scale curved thin films

Energy Technology Data Exchange (ETDEWEB)

Mansoor, Saad B.; Yilbas, Bekir S., E-mail: bsyilbas@kfupm.edu.sa

2016-12-15

Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

Phonon transport across nano-scale curved thin films

International Nuclear Information System (INIS)

Mansoor, Saad B.; Yilbas, Bekir S.

2016-01-01

Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

RELAP5 Prediction of Transient Tests in the RD-14 Test Facility

International Nuclear Information System (INIS)

Lee, Sukho; Kim, Manwoong; Kim, Hho-Jung; Lee, John C.

2005-01-01

Although the RELAP5 computer code has been developed for best-estimate transient simulation of a pressurized water reactor and its associated systems, it could not assess the thermal-hydraulic behavior of a Canada deuterium uranium (CANDU) reactor adequately. However, some studies have been initiated to explore the applicability for simulating a large-break loss-of-coolant accident in CANDU reactors. In the present study, the small-reactor inlet header break test and the steam generator secondary-side depressurization test conducted in the RD-14 test facility were simulated with the RELAP5/MOD3.2.2 code to examine its extended capability for all the postulated transients and accidents in CANDU reactors. The results were compared with experimental data and those of the CATHENA code performed by Atomic Energy of Canada Limited.In the RELAP5 analyses, the heated sections in the facility were simulated as a multichannel with five pipe models, which have identical flow areas and hydraulic elevations, as well as a single-pipe model.The results of the small-reactor inlet header break and the steam generator secondary-side depressurization simulations predicted experimental data reasonably well. However, some discrepancies in the depressurization of the primary heat transport system after the header break and consequent time delay of the major phenomena were observed in the simulation of the small-reactor inlet header break test

Internal transport barrier in tokamak and helical plasmas

Science.gov (United States)

Ida, K.; Fujita, T.

2018-03-01

The differences and similarities between the internal transport barriers (ITBs) of tokamak and helical plasmas are reviewed. By comparing the characteristics of the ITBs in tokamak and helical plasmas, the mechanisms of the physics for the formation and dynamics of the ITB are clarified. The ITB is defined as the appearance of discontinuity of temperature, flow velocity, or density gradient in the radius. From the radial profiles of temperature, flow velocity, and density the ITB is characterized by the three parameters of normalized temperature gradient, R/{L}T, the location, {ρ }{ITB}, and the width, W/a, and can be expressed by ‘weak’ ITB (small R/{L}T) or ‘strong’ (large R/{L}T), ‘small’ ITB (small {ρ }{ITB}) or ‘large’ ITB (large {ρ }{ITB}), and ‘narrow’ (small W/a) or ‘wide’ (large W/a). Three key physics elements for the ITB formation, radial electric field shear, magnetic shear, and rational surface (and/or magnetic island) are described. The characteristics of electron and ion heat transport and electron and impurity transport are reviewed. There are significant differences in ion heat transport and electron heat transport. The dynamics of ITB formation and termination is also discussed. The emergence of the location of the ITB is sometimes far inside the ITB foot in the steady-state phase and the ITB region shows radial propagation during the formation of the ITB. The non-diffusive terms in momentum transport and impurity transport become more dominant in the plasma with the ITB. The reversal of the sign of non-diffusive terms in momentum transport and impurity transport associated with the formation of the ITB reported in helical plasma is described. Non-local transport plays an important role in determining the radial profile of temperature and density. The spontaneous change in temperature curvature (second radial derivative of temperature) in the ITB region is described. In addition, the key parameters of the control of the

Supercurrent transport properties in Nd substituted TlSr2CaCu2O7 high temperature superconductor

International Nuclear Information System (INIS)

Andrew Das Arulsamy; Abd Shukor, R.

1999-01-01

The transport critical current density, J ct of TI(Sr 1-x Nd x ) 2 CaCu 2 O 7 (x= 0.1, 0.2 and 0.3) high temperature superconductors were measured at various temperatures. X-ray diffraction patterns indicate that all samples consist of mainly of the 1212 phase. The variation of J ct with Nd concentration, temperature and T c were scaled using a universal function. By plotting J ct versus T n c (x) and [1-(T/T c ) 2 ] m , we can divide the temperature dependencies of J ct into two regions. In each region, a linear relationship is suggested to hold between J ct and [1-(T/T c ) 2 ] m . For x=0.1, a relatively large exponent m in the range 40 - 50 K is observed, but a lower value is observed for a higher temperature range, 55 - 60 K. Average m for x = 0. 1 in the range 40 - 70 K is 1.8 but for x=0.2 and 0.3, m is 0.6 and 1.2, respectively. This can be interpreted as an indication that there is a change in the elementary flux pinning force which is responsible for sustaining the supercurrent. A self-field approximation indicates that Nd substitution lowers the distance between pinning centers (L c ). (author)

Improving xylitol production at elevated temperature with engineered Kluyveromyces marxianus through over-expressing transporters.

Science.gov (United States)

Zhang, Jia; Zhang, Biao; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

2015-01-01

Three transporter genes including Kluyveromyces marxianus aquaglyceroporin gene (KmFPS1), Candida intermedia glucose/xylose facilitator gene (CiGXF1) or glucose/xylose symporter gene (CiGXS1) were over-expressed in K. marxianus YZJ017 to improve xylitol production at elevated temperatures. The xylitol production of YZJ074 that harbored CiGXF1 was improved to 147.62g/L in Erlenmeyer flask at 42°C. In fermenter, 99.29 and 149.60g/L xylitol were produced from 99.55 and 151.91g/L xylose with productivity of 4.14 and 3.40g/L/h respectively at 42°C. Even at 45°C, YZJ074 could produce 101.30g/L xylitol from 101.41g/L xylose with productivity of 2.81g/L/h. Using fed-batch fermentation through repeatedly adding non-sterilized substrate directly, YZJ074 could produce 312.05g/L xylitol which is the highest yield reported to date. The engineered strains YZJ074 which can produce xylitol at elevated temperatures is an excellent foundation for xylitol bioconversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Silicotungstate, a Potential Electron Transporting Layer for Low-Temperature Perovskite Solar Cells.

Science.gov (United States)

Choi, Yoon Ho; Kim, Hyun Bin; Yang, In Seok; Sung, Sang Do; Choi, Young Sik; Kim, Jeongho; Lee, Wan In

2017-08-02

Thin films of a heteropolytungstate, lithium silicotungstate (Li 4 SiW 12 O 40 , termed Li-ST), prepared by a solution process at low temperature, were successfully applied as electron transporting layer (ETL) of planar-type perovskite solar cells (PSCs). Dense and uniform Li-ST films were prepared on FTO glass by depositing a thin Li-ST buffer layer, followed by coating of a main Li-ST layer. The film thickness was controlled by varying the number of coating cycles, consisting of spin-coating and thermal treatment at 150 °C. In particular, by employing 60 nm-thick Li-ST layer obtained by two cycles of coating, the fabricated CH 3 NH 3 PbI 3 PSC device demonstrates the photovoltaic conversion efficiency (PCE) of 14.26% with J SC of 22.16 mA cm -2 , V OC of 0.993 mV and FF of 64.81%. The obtained PCE is significantly higher than that of the PSC employing a TiO 2 layer processed at the same temperature (PCE = 12.27%). Spectroscopic analyses by time-resolved photoluminescence and pulsed light-induced transient measurement of photocurrent indicate that the Li-ST layer collects electrons from CH 3 NH 3 PbI 3 more efficiently and also exhibits longer electron lifetime than the TiO 2 layer thermally treated at 150 °C. Thus, Li-ST is considered to be a promising ETL material that can be applied for the fabrication of flexible PSC devices.

Metal/dielectric thermal interfacial transport considering cross-interface electron-phonon coupling: Theory, two-temperature molecular dynamics, and thermal circuit

Science.gov (United States)

Lu, Zexi; Wang, Yan; Ruan, Xiulin

2016-02-01

The standard two-temperature equations for electron-phonon coupled thermal transport across metal/nonmetal interfaces are modified to include the possible coupling between metal electrons with substrate phonons. The previous two-temperature molecular dynamics (TT-MD) approach is then extended to solve these equations numerically at the atomic scale, and the method is demonstrated using Cu/Si interface as an example. A key parameter in TT-MD is the nonlocal coupling distance of metal electrons and nonmetal phonons, and here we use two different approximations. The first is based on Overhauser's "joint-modes" concept, while we use an interfacial reconstruction region as the length scale of joint region rather than the phonon mean-free path as in Overhauser's original model. In this region, the metal electrons can couple to the joint phonon modes. The second approximation is the "phonon wavelength" concept where electrons couple to phonons nonlocally within the range of one phonon wavelength. Compared with the original TT-MD, including the cross-interface electron-phonon coupling can slightly reduce the total thermal boundary resistance. Whether the electron-phonon coupling within the metal block is nonlocal or not does not make an obvious difference in the heat transfer process. Based on the temperature profiles from TT-MD, we construct a new mixed series-parallel thermal circuit. We show that such a thermal circuit is essential for understanding metal/nonmetal interfacial transport, while calculating a single resistance without solving temperature profiles as done in most previous studies is generally incomplete. As a comparison, the simple series circuit that neglects the cross-interface electron-phonon coupling could overestimate the interfacial resistance, while the simple parallel circuit in the original Overhauser's model underestimates the total interfacial resistance.

Sea surface temperature and Ekman transport in the Persian Gulf

Directory of Open Access Journals (Sweden)

E. H.

2002-12-01

Full Text Available   The wind drift motion of the water which is produced by the stress of the wind exerted upon the surface of the ocean is described by Ekmans theory (1905. Using the mean monthly values for the wind stress and SST, seasonal Ekman transport for the Persian Gulf was computed and contoured. The geostrophic winds have combined with the SST to estimate the effect of cooling due to Ekman transport of colder northern waters and inflow from the Oman Sea. The monthly SST mainly obtained from the 10 10 grided data of Levitus atlas and Hormuz Cruis Experiment for 1997.   Analyses show a NW to SE Ekman transport due to wind stress and significant interannual variability of SST on sea surface in the Persian Gulf. The seasonal variation of SST shows a continental pattern due to severe interaction between the land and sea. But these variations somehow moderates because of Ekman transport in Persian Gulf.

Effect of tearing modes on temperature and density profiles and on the perpendicular transport in the W VII-A stellarator

International Nuclear Information System (INIS)

Jaenicke, R.

1988-01-01

In the ohmically heated W VII-A stellarator, the behaviour of which is similar to that of a medium sized tokamak, the additional shearless external rotational transform t 0 (Δt 0 /t 0 0 perpendicular,e in a one-dimensional heat transport code. In this way, the measured temperature profiles can be reproduced quite well and the energy confinement time of discharges with tearing mode activity can be predicted quantitatively. The transport model is used to investigate the explicit dependence of κ perpendicular,e on the plasma current and to study the importance of plasma current driven instabilities for the energy confinement in the W VII-A stellarator as well as in tokamaks. (author). 19 refs, 14 figs

Ultrasonic decontamination robot

International Nuclear Information System (INIS)

Patenaude, R.S.

1984-01-01

An ultrasonic decontamination robot removes radioactive contamination from the internal surface of the inlet and outlet headers, divider plate, tube sheet, and lower portions of tubes of a nuclear power plant steam generator. A programmable microprocessor controller guides the movement of a robotic arm mounted in the header manway. An ultrasonic transducer having a solvent delivery subsystem through which ultrasonic action is achieved is moved by the arm over the surfaces. A solvent recovery suction tube is positioned within the header to remove solvent therefrom while avoiding interference with the main robotic arm. The solvent composition, temperature, pressure, viscosity, and purity are controlled to optimize the ultrasonic scrubbing action. The ultrasonic transducer is controlled at a power density, frequency, and on-off mode cycle such as to optimize scrubbing action within the range of transducer-to-surface distance and solvent layer thickness selected for the particular conditions encountered. Both solvent and transducer control actions are optimized by the programmable microprocessor. (author)

Critical transport current in granular high temperature superconductors

International Nuclear Information System (INIS)

Bogolyubov, N.A.

1999-01-01

The temperature and size dependence of the critical current in a zero magnetic field of three bismuth-based ceramic samples with round cross section and one sample with rectangular triangle cross section have been studied by a contactless technique. It is shown that the critical current can be presented as a product of the temperature and size dependent factors. The temperature-dependent multiplier reflects the individual peculiarities of the Josephson net of each sample, while the size factor is a homogeneous function of the cross-section sizes. The index of this function is independent of the cross-section form, the temperature and individual properties of HTSC samples. The radial distribution of critical current density in round samples and dependence of the critical current density on the magnetic conduction in granular HTSC have been found from the analysis of experimental data

Resolving the mystery of transport within internal transport barriers

Energy Technology Data Exchange (ETDEWEB)

Staebler, G. M.; Belli, E. A.; Candy, J.; Waltz, R. E.; Greenfield, C. M.; Lao, L. L.; Smith, S. P. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Kinsey, J. E. [CompX, P.O. Box 2672, Del Mar, California 92014-5672 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States); Chrystal, C. [University of California-San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)

2014-05-15

The Trapped Gyro-Landau Fluid (TGLF) quasi-linear model [G. M. Staebler, et al., Phys. Plasmas 12, 102508 (2005)], which is calibrated to nonlinear gyrokinetic turbulence simulations, is now able to predict the electron density, electron and ion temperatures, and ion toroidal rotation simultaneously for internal transport barrier (ITB) discharges. This is a strong validation of gyrokinetic theory of ITBs, requiring multiple instabilities responsible for transport in different channels at different scales. The mystery of transport inside the ITB is that momentum and particle transport is far above the predicted neoclassical levels in apparent contradiction with the expectation from the theory of suppression of turbulence by E×B velocity shear. The success of TGLF in predicting ITB transport is due to the inclusion of ion gyro-radius scale modes that become dominant at high E×B velocity shear and to improvements to TGLF that allow momentum transport from gyrokinetic turbulence to be faithfully modeled.

Quench behavior of Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}/Ag tapes with AC and DC transport currents at different temperature

Energy Technology Data Exchange (ETDEWEB)

Liu, Qi [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Institute of Science, Information Engineering University, Zhengzhou 450001 (China); Zhang, Guomin, E-mail: gmzhang@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Hua [Institute of Science, Information Engineering University, Zhengzhou 450001 (China); Li, Zhenming; Liu, Wei [China Electric Power Research Institute, Beijing 100192 (China); Jing, Liwei [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yu, Hui; Liu, Guole [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China)

2016-09-15

Highlights: • Quench behavior of Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}/ Ag tape with AC transport current was reported for the first time. • The measurement are performed as a function of different temperature (20 K–30 K), transport current (AC and DC) and operating frequency (50 Hz–250 Hz). • The study is concentrated on the research of quench development, and the discussions of NZPV and MQE values. - Abstract: In applications, superconducting wires may carry AC or DC transport current. Thus, it is important to understand the behavior of normal zone propagation in conductors and magnets under different current conditions in order to develop an effective quench protection system. In this paper, quench behavior of Ag sheathed Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2} (Sr-122 in the family of iron-based superconductor) tapes with AC and DC transport current is reported. The measurements are performed as a function of different temperature (20 K–30 K), varying transport current and operating frequency (50 Hz–250 Hz). The focus of the research is the minimum quench energy (MQE), the normal zone propagation velocity (NZPV) and the comparison of the related results with AC and DC transport current.

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

Science.gov (United States)

Yi, Kan; Liu, Junfeng; Ban-Weiss, George; Zhang, Jiachen; Tao, Wei; Cheng, Yanli; Tao, Shu

2017-07-01

The response of surface ozone (O3) concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM). Idealized, spatially uniform sea surface temperature (SST) anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage between basin-scale SST

Response of the global surface ozone distribution to Northern Hemisphere sea surface temperature changes: implications for long-range transport

Directory of Open Access Journals (Sweden)

K. Yi

2017-07-01

Full Text Available The response of surface ozone (O3 concentrations to basin-scale warming and cooling of Northern Hemisphere oceans is investigated using the Community Earth System Model (CESM. Idealized, spatially uniform sea surface temperature (SST anomalies of ±1 °C are individually superimposed onto the North Pacific, North Atlantic, and North Indian oceans. Our simulations suggest large seasonal and regional variability in surface O3 in response to SST anomalies, especially in the boreal summer. The responses of surface O3 associated with basin-scale SST warming and cooling have similar magnitude but are opposite in sign. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv. With fixed emissions, SST increases in a specific ocean basin in the Northern Hemisphere tend to increase the summertime surface O3 concentrations over upwind regions, accompanied by a widespread reduction over downwind continents. We implement the integrated process rate (IPR analysis in CESM and find that meteorological O3 transport in response to SST changes is the key process causing surface O3 perturbations in most cases. During the boreal summer, basin-scale SST warming facilitates the vertical transport of O3 to the surface over upwind regions while significantly reducing the vertical transport over downwind continents. This process, as confirmed by tagged CO-like tracers, indicates a considerable suppression of intercontinental O3 transport due to increased tropospheric stability at lower midlatitudes induced by SST changes. Conversely, the responses of chemical O3 production to regional SST warming can exert positive effects on surface O3 levels over highly polluted continents, except South Asia, where intensified cloud loading in response to North Indian SST warming depresses both the surface air temperature and solar radiation, and thus photochemical O3 production. Our findings indicate a robust linkage

Thermodynamic performance of R502 alternative refrigerant mixtures for low temperature and transport applications

International Nuclear Information System (INIS)

Park, Ki-Jung; Jung, Dongsoo

2007-01-01

In this study, two pure hydrocarbon refrigerants, R1270 (propylene) and R290 (propane), and three binary mixtures composed of R1270, R290 and R152a were tested in a refrigerating bench tester with a scroll compressor in an attempt to substitute R502, which is used in most low temperature and transport refrigeration applications. The test bench provided 3-3.5 kW capacity, and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions, resulting in the average saturation temperatures of -28 and 45 o C in the evaporator and condenser, respectively. The test results showed that all refrigerants tested had 9.6-18.7% higher capacity and 17.1-27.3% higher COP than R502. The compressor discharge temperature of R1270 was similar to that of R502, while those of all the other refrigerants were 23.7-27.9 o C lower than that of R502. For all alternative refrigerants, the charge was reduced up to 60% as compared to R502. There, of course, was no problem with mineral oil, since the mixtures were mainly composed of hydrocarbons. Since some of them are mixtures, one can change their compositions a little to suit various needs in many applications without significant deterioration of the performance. Overall, these alternative refrigerants offer better system performance and reliability than R502 and can be used as long term substitutes for R502 due to their excellent environmental properties

Reducing Turbulent Transport in Toroidal Configurations via Shaping

International Nuclear Information System (INIS)

Mynick, H.E.; Pomphrey, N.; Xanthopoulos, P.

2011-01-01

Recent progress in reducing turbulent transport in stellarators and tokamaks by 3D shaping using a stellarator optimization code in conjunction with a gyrokinetic code is presented. The original applications of the method focussed on ion temperature gradient transport in a quasi-axisymmetric stellarator design. Here, an examination of both other turbulence channels and other starting configurations is initiated. It is found that the designs evolved for transport from ion temperature gradient turbulence also display reduced transport from other transport channels whose modes are also stabilized by improved curvature, such as electron temperature gradient and ballooning modes. The optimizer is also applied to evolving from a tokamak, finding appreciable turbulence reduction for these devices as well. From these studies, improved understanding is obtained of why the deformations found by the optimizer are beneficial, and these deformations are related to earlier theoretical work in both stellarators and tokamaks.

Charge carrier transport mechanisms in nanocrystalline indium oxide

International Nuclear Information System (INIS)

Forsh, E.A.; Marikutsa, A.V.; Martyshov, M.N.; Forsh, P.A.; Rumyantseva, M.N.; Gaskov, A.M.; Kashkarov, P.K.

2014-01-01

The charge transport properties of nanocrystalline indium oxide (In 2 O 3 ) are studied. A number of nanostructured In 2 O 3 samples with various nanocrystal sizes are prepared by sol–gel method and characterized using various techniques. The mean nanocrystals size varies from 7–8 nm to 18–20 nm depending on the conditions of their preparation. Structural characterizations of the In 2 O 3 samples are performed by means of transmission electron microscopy and X-ray diffraction. The analysis of dc and ac conductivity in a wide temperature range (T = 50–300 K) shows that at high temperatures charge carrier transport takes place over conduction band and at low temperatures a variable range hopping transport mechanism can be observed. We find out that the temperature of transition from one mechanism to another depends on nanocrystal size: the transition temperature rises when nanocrystals are bigger in size. The average hopping distance between two sites and the activation energy are calculated basing on the analysis of dc conductivity at low temperature. Using random barrier model we show a uniform hopping mechanism taking place in our samples and conclude that nanocrystalline In 2 O 3 can be regarded as a disordered system. - Highlights: • In 2 O 3 samples with various nanocrystal sizes are prepared by sol–gel method. • The mean nanocrystal size varies from 7–8 nm to 18–20 nm. • At high temperatures charge carrier transport takes place over conduction band. • At low temperatures a variable range hopping transport mechanism can be observed. • We show a uniform hopping mechanism taking place in our samples

Ion anomalous transport and feedback control. Final technical report, September 1, 1987 - August 31, 1997

International Nuclear Information System (INIS)

Sen, A.K.

1998-01-01

This final report is comprised of the following six progress reports: Ion Temperature Gradient Instability and Anomalous Transport, July 1989; Ion Temperature Gradient Instability and Anomalous Transport, August 1991; Ion Temperature Gradient Instability and Anomalous Transport, July 1993; Ion Anomalous Transport and Feedback Control, May 1994; Ion Anomalous Transport and Feedback Control, April 1995; and Ion Anomalous Transport and Feedback Control, December 1997

Average-atom model for two-temperature states and ionic transport properties of aluminum in the warm dense matter regime

Science.gov (United States)

Hou, Yong; Fu, Yongsheng; Bredow, Richard; Kang, Dongdong; Redmer, Ronald; Yuan, Jianmin

2017-03-01

The average-atom model combined with the hyper-netted chain approximation is an efficient tool for electronic and ionic structure calculations for warm dense matter. Here we generalize this method in order to describe non-equilibrium states with different electron and ion temperature as produced in laser-matter interactions on ultra-short time scales. In particular, the electron-ion and ion-ion correlation effects are considered when calculating the electron structure. We derive an effective ion-ion pair-potential using the electron densities in the framework of temperature-depended density functional theory. Using this ion-ion potential we perform molecular dynamics simulations in order to determine the ionic transport properties such as the ionic diffusion coefficient and the shear viscosity through the ionic velocity autocorrelation functions.

Low-temperature, solution-processed aluminum-doped zinc oxide as electron transport layer for stable efficient polymer solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhu, Qianqian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Yu, Jianhua [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Dangqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Zhang, Qian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Gu, Chuantao [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Hongzhou [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Yang, Renqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Lifeng, E-mail: DongLifeng@qust.edu.cn [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Department of Physics, Hamline University, St. Paul, MN 55104 (United States)

2016-04-30

A simple low-temperature solution-processed zinc oxide (ZnO) and aluminum-doped ZnO (AZO) were synthesized and investigated as an electron transport layer (ETL) for inverted polymer solar cells. A solar cell with a blend of poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′] dithiophene-alt-alkylcarbonyl-thieno [3,4-b] thiophene) and (6,6)-phenyl-C71-butyric acid methyl ester as an active layer and AZO as ETL demonstrates a high power conversion efficiency (PCE) of 7.36% under the illumination of AM 1.5G, 100 mW/cm{sup 2}. Compared to the cells with ZnO ETL (PCE of 6.85%), the PCE is improved by 7.45% with the introduction of an AZO layer. The improved PCE is ascribed to the enhanced short circuit current density, which results from the electron transport property of the AZO layer. Moreover, AZO is a more stable interfacial layer than ZnO. The PCE of the solar cells with AZO as ETL retain 85% of their original value after storage for 120 days, superior to the 39% of cells with ZnO ETL. The results above indicate that a simple low-temperature solution-processed AZO film is an efficient and economical ETL for high-performance inverted polymer solar cells. Due to its environmental friendliness, good electrical properties, and simple preparation approach, AZO has the potential to be applied in high-performance, large-scale industrialization of solar cells and other electronic devices. - Highlights: • ZnO and AZO were synthesized by a simple low-temperature solution-processed method. • AZO films show high transmittance and conductivity. • The photovoltaic performance can be improved with AZO as ETL. • AZO-based devices demonstrate excellent stability, with 85% retained after 120 days.

Electron heat transport analysis of low-collisionality plasmas in the neoclassical-transport-optimized configuration of LHD

International Nuclear Information System (INIS)

Murakami, Sadayoshi; Yamada, Hiroshi; Wakasa, Arimitsu

2002-01-01

Electron heat transport in low-collisionality LHD plasma is investigated in order to study the neoclassical transport optimization effect on thermal plasma transport with an optimization level typical of so-called ''advanced stellarators''. In the central region, a higher electron temperature is obtained in the optimized configuration, and transport analysis suggests the considerable effect of neoclassical transport on the electron heat transport assuming the ion-root level of radial electric field. The obtained experimental results support future reactor design in which the neoclassical and/or anomalous transports are reduced by magnetic field optimization in a non-axisymmetric configuration. (author)

Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger

International Nuclear Information System (INIS)

Chen, Minghui; Sun, Xiaodong; Christensen, Richard N.; Skavdahl, Isaac; Utgikar, Vivek; Sabharwall, Piyush

2016-01-01

Highlights: • Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger have been obtained. • Comparisons of experimental data and available correlations have been performed. • New Fanning friction factor and heat transfer correlations for the test PCHE are developed. - Abstract: Printed circuit heat exchanger (PCHE) is one of the leading intermediate heat exchanger (IHX) candidates to be employed in the very-high-temperature gas-cooled reactors (VHTRs) due to its capability for high-temperature, high-pressure applications. In the current study, a reduced-scale zigzag-channel PCHE was fabricated using Alloy 617 plates for the heat exchanger core and Alloy 800H pipes for the headers. The pressure drop and heat transfer characteristics of the PCHE were investigated experimentally in a high-temperature helium test facility (HTHF) at The Ohio State University. The PCHE helium inlet temperatures and pressures were varied up to 464 °C/2.7 MPa for the cold side and 802 °C/2.7 MPa for the hot side, respectively, while the maximum helium mass flow rates on both sides of the PCHE reached 39 kg/h. The corresponding maximum channel Reynolds number was approximately 3558, covering the laminar flow and laminar-to-turbulent flow transition regimes. New pressure drop and heat transfer correlations for the current zigzag channels with rounded bends were developed based on the experimental data. Comparisons between the experimental data and the results obtained from the available PCHE and straight circular pipe correlations were conducted. Compared to the heat transfer performance in straight circular pipes, the zigzag channels provided little advantage in the laminar flow regime but significant advantage near the transition flow regime.

Theoretical study of energetic interactions between high temperature molten materials and a low temperature fluid

International Nuclear Information System (INIS)

Chen, S.H.H.

1984-01-01

Analytical models are developed to predict the hydrodynamical transients resulting from the energetic interactions between a high temperature molten material and a low temperature liquid coolant. Initially, the molten material at high temperature and pressure is separated from the low temperature fluid by a solid metal barrier. Upon contact between the molten material and solid barrier, thermal attack occurs eventually resulting in a loss of barrier integrity. Subsequently, the molten material is injected into the liquid pool resulting in energetic interactions. The analytical models integrate a wide variety of potentially mutually-interacting transport phenomena which dominate the transient process into a deterministic scheme to predict the hydrodynamic transient process into a deterministic scheme to predict the hydrodynamic transient process. The model calculations are compared with the existing experimental results to show its engineering accuracy and adequacy in predicting such energetic interactions. Two models are formulated to bracket the transport of molten material to the rupture site for the reactor system. The stratified model minimized the rate of transport of material to the break location while the dispersed model maximized such transport. These two models are applied to a reference pressure tube reactor to evaluate the pressure transients and the potential structural damages as a result of a postulated severe primary coolant blockage in a power channel

Experimental demonstrations of all-optical networking functions for WDM optical networks

Science.gov (United States)

Gurkan, Deniz

The deployment of optical networks will enable high capacity links between users but will introduce the problems associated with transporting and managing more channels. Many network functions should be implemented in optical domain; main reasons are: to avoid electronic processing bottlenecks, to achieve data-format and data-rate independence, to provide reliable and cost efficient control and management information, to simultaneously process multiple wavelength channel operation for wavelength division multiplexed (WDM) optical networks. The following novel experimental demonstrations of network functions in the optical domain are presented: Variable-bit-rate recognition of the header information in a data packet. The technique is reconfigurable for different header sequences and uses optical correlators as look-up tables. The header is processed and a signal is sent to the switch for a series of incoming data packets at 155 Mb/s, 622 Mb/s, and 2.5 Gb/s in a reconfigurable network. Simultaneous optical time-slot-interchange and wavelength conversion of the bits in a 2.5-Gb/s data stream to achieve a reconfigurable time/wavelength switch. The technique uses difference-frequency-generation (DFG) for wavelength conversion and fiber Bragg gratings (FBG) as wavelength-dependent optical time buffers. The WDM header recognition module simultaneously recognizing two header bits on each of two 2.5-Gbit/s WDM packet streams. The module is tunable to enable reconfigurable look-up tables. Simultaneous and independent label swapping and wavelength conversion of two WDM channels for a multi-protocol label switching (MPLS) network. Demonstration of label swapping of distinct 8-bit-long labels for two WDM data channels is presented. Two-dimensional code conversion module for an optical code-division multiple-access (O-CDMA) local area network (LAN) system. Simultaneous wavelength conversion and time shifting is achieved to enable flexible code conversion and increase code re

Enhancing Thermoelectric Performance Using Nonlinear Transport Effects

Science.gov (United States)

Jiang, Jian-Hua; Imry, Yoseph

2017-06-01

We study nonlinear transport effects on the maximum efficiency and power for both inelastic and elastic thermoelectric generators. The former device refers to phonon-assisted hopping in double quantum dots, while the latter device is represented by elastic tunneling through a single quantum dot. We find that nonlinear thermoelectric transport can lead to enhanced efficiency and power for both types of devices. A comprehensive survey of various quantum-dot energy, temperature, and parasitic heat conduction reveals that the nonlinear transport-induced improvements of the maximum efficiency and power are overall much more significant for inelastic devices than for elastic devices, even for temperature biases as small as Th=1.2 Tc (Th and Tc are the temperatures of the hot and cold reservoirs, respectively). The underlying mechanism is revealed as due to the fact that, unlike the Fermi distribution, the Bose distribution is not bounded when the temperature bias increases. A large flux density of absorbed phonons leads to a great enhancement of the electrical current, output power, and energy efficiency, dominating over the concurrent increase of the parasitic heat current. Our study reveals that nonlinear transport effects can be a useful tool for improving thermoelectric performance.

Header [nuclear battery

International Nuclear Information System (INIS)

Goslee, D.E.; Barr, H.N.

1976-01-01

The invention relates to a nuclear-powered microwatt thermoelectric generator, small in size, efficient in operation, and which will last for a considerable period of time. The generator is suitable for implanting within the human body for powering devices such as cardiac pacemakers

A kinetic study of mercury(II transport through a membrane assisted by new transport reagent

Directory of Open Access Journals (Sweden)

Görgülü Ahmet

2011-07-01

Full Text Available Abstract Background A new organodithiophosphorus derivative, namely O-(1,3-Bispiperidino-2-propyl-4-methoxy phenyldithiophosphonate, was synthesized and then the kinetic behavior of the transport process as a function of concentration, temperature, stirring rate and solvents was investigated. Results The compound 1 was characterized by elemental analysis, IR, 1H and 31P NMR spectroscopies. The transport of mercury(II ion by a zwitterionic dithiophosphonate 1 in the liquid membrane was studied and the kinetic behavior of the transport process as a function of concentration, temperature, stirring rate and solvents was investigated. The compound 1 is expected to serve as a model liquid membrane transport with mercury(II ions. Conclusion A kinetic study of mercury(II transport through a membrane assisted by O-(1,3-Bispiperidino-2-propyl-4-methoxy phenyldithiophosphonate was performed. It can be concluded that the compound 1 can be provided a general and straightforward route to remove toxic metals ions such as mercury(II ion from water or other solution.

Transport through dissipative trapped electron mode and toroidal ion temperature gradient mode in TEXTOR

International Nuclear Information System (INIS)

Rogister, A.; Hasselberg, G.; Waelbroeck, F.; Weiland, J.

1987-12-01

A self-consistent transport code is used to evaluate how plasma confinement in tokamaks is influenced by the microturbulent fields which are excited by the dissipative trapped electron (DTE) instability. As shown previously, the saturation theory on which the code is based has been developed from first principles. The toroidal coupling resulting from the ion magnetic drifts is neglected; arguments are presented to justify this approximation. The numerical results reproduce well the neo-Alcator scaling law observed experimentally - e.g. in TEXTOR - in non detached ohmic discharges, the confinement degradation which results when auxiliary heating is applied, as well as a large number of other experimental observations. We also assess the possible impact of the toroidal ion temperature gradient mode on energy confinement by estimating the ion thermal flux with the help of the mixing length approximation. (orig./GG)

Passive cooling during transport of asphyxiated term newborns

Science.gov (United States)

O’Reilly, Deirdre; Labrecque, Michelle; O’Melia, Michael; Bacic, Janine; Hansen, Anne; Soul, Janet S

2014-01-01

Objective To evaluate the efficacy and safety of passive cooling during transport of asphyxiated newborns. Study Design Retrospective medical record review of newborns with perinatal asphyxia transported for hypothermia between July 2007 and June 2010. Results Forty-three newborns were transported, 27 of whom were passively cooled. Twenty (74%) passively cooled newborns arrived with axillary temperature between 32.5 and 34.5 °C. One newborn (4%) arrived with a subtherapeutic temperature, and 6 (22%) had temperatures >34.5 °C. Time from birth to hypothermia was significantly shorter among passively cooled newborns compared with newborns not cooled (215 vs. 327 minutes, pencephalopathy results in significantly earlier achievement of effective therapeutic hypothermia without significant adverse events. PMID:23154670

A Surface-Layer Study of the Transport and Dissipation of Turbulent Kinetic Energy and the Variances of Temperature, Humidity and CO_2

Science.gov (United States)

Hackerott, João A.; Bakhoday Paskyabi, Mostafa; Reuder, Joachim; de Oliveira, Amauri P.; Kral, Stephan T.; Marques Filho, Edson P.; Mesquita, Michel dos Santos; de Camargo, Ricardo

2017-11-01

We discuss scalar similarities and dissimilarities based on analysis of the dissipation terms in the variance budget equations, considering the turbulent kinetic energy and the variances of temperature, specific humidity and specific CO_2 content. For this purpose, 124 high-frequency sampled segments are selected from the Boundary Layer Late Afternoon and Sunset Turbulence experiment. The consequences of dissipation similarity in the variance transport are also discussed and quantified. The results show that, for the convective atmospheric surface layer, the non-dimensional dissipation terms can be expressed in the framework of Monin-Obukhov similarity theory and are independent of whether the variable is temperature or moisture. The scalar similarity in the dissipation term implies that the characteristic scales of the atmospheric surface layer can be estimated from the respective rate of variance dissipation, the characteristic scale of temperature, and the dissipation rate of temperature variance.

Metal-semiconductor interface in extreme temperature conditions

International Nuclear Information System (INIS)

Bulat, L.P.; Erofeeva, I.A.; Vorobiev, Yu.V.; Gonzalez-Hernandez, J.

2008-01-01

We present an investigation of electrons' and phonons' temperatures in the volume of a semiconductor (or metal) sample and at the interface between metal and semiconductor. Two types of mismatch between electrons' and phonons' temperatures take place: at metal-semiconductor interfaces and in the volume of the sample. The temperature mismatch leads to nonlinear terms in expressions for heat and electricity transport. The nonlinear effects should be taken into consideration in the study of electrical and heat transport in composites and in electronic chips

Temperature-salinity structure of the AMOC in high-resolution ocean simulations and in CMIP5 models

Science.gov (United States)

Wang, F.; Xu, X.; Chassignet, E.

2017-12-01

On average, the CMIP5 models represent the AMOC structure, water properties, Heat transport and Freshwater transport reasonably well. For temperature, CMIP5 models exhibit a colder northward upper limb and a warmer southward lower limb. the temperature contrast induces weaker heat transport than observation. For salinity, CMIP5 models exhibit saltier southward lower limb, thus contributes to weaker column freshwater transport. Models have large spread, among them, AMOC strength contributes to Heat transport but not freshwater transport. AMOC structure (the overturning depth) contributes to transport-weighted temperature not transport-weighted salinity in southward lower limb. The salinity contrast in upper and lower limb contributes to freshwater transport, but temperature contrast do not contribute to heat transport.

Electrical transport properties of calcium and barium aluminates

NARCIS (Netherlands)

Metselaar, R.; Hoefsloot, A.M.

1987-01-01

Electrical conductivity and ionic transport numbers have been measured of barium and calcium aluminates with composition CaO·nAl2O3 (n=7/12, 1, 2, 6) and 0.82 BaO·6Al2O3. At room temperatures these compounds are insulators, but at high temperatures mixed conductivity is observed. Ionic transport

Caracterização das publicações periódicas em fonoaudiologia e neurociências: estudo sobre os tipos e temas de artigos e visibilidade na área de linguagem Periodicals' profile in speech-language and hearing pathology and neurosciences: study on types and headers of the language area articles, and their visibility

Directory of Open Access Journals (Sweden)

Sandrelli Virginio de Vasconcelos

2009-03-01

Full Text Available TEMA: caracterização das publicações periódicas em Fonoaudiologia e Neurociências: estudo sobre os tipos e temas de artigos e visibilidade na área de linguagem. OBJETIVO: caracterizar as publicações periódicas em Fonoaudiologia estudando os artigos da área de Linguagem relacionados às Neurociências no período de 2002 a 2006. CONCLUSÃO: ficou evidente um aumento crescente de publicações em Linguagem e em Neurociências nos últimos cinco anos. Contudo, o número de publicações em determinados temas como a Dislexia, a Doença de Alzheimer e o Transtorno do Déficit de Atenção / Hiperatividade ainda mostra-se resumido.BACKGROUND: periodicals' profile in speechlanguage and hearing pathology and neurosciences: study on types and headers of the language articles, and their visibility. PURPOSE: to characterize periodicals in SpeechLanguage Pathology and Hearing, studying the articles of the Language's area related to Neurosciences in the period from 2002 to 2006. CONCLUSION: increasing publication in Language and Neurosciences in the last five years has been evident. However, number of publications in certain headers, such as dyslexia, Alzheimer's disease and AttentionDeficit/Hyperactivity Disorder are still abridged.

ADVANCED CUTTINGS TRANSPORT STUDY

Energy Technology Data Exchange (ETDEWEB)

Stefan Miska; Troy Reed; Ergun Kuru

2004-09-30

The Advanced Cuttings Transport Study (ACTS) was a 5-year JIP project undertaken at the University of Tulsa (TU). The project was sponsored by the U.S. Department of Energy (DOE) and JIP member companies. The objectives of the project were: (1) to develop and construct a new research facility that would allow three-phase (gas, liquid and cuttings) flow experiments under ambient and EPET (elevated pressure and temperature) conditions, and at different angle of inclinations and drill pipe rotation speeds; (2) to conduct experiments and develop a data base for the industry and academia; and (3) to develop mechanistic models for optimization of drilling hydraulics and cuttings transport. This project consisted of research studies, flow loop construction and instrumentation development. Following a one-year period for basic flow loop construction, a proposal was submitted by TU to the DOE for a five-year project that was organized in such a manner as to provide a logical progression of research experiments as well as additions to the basic flow loop. The flow loop additions and improvements included: (1) elevated temperature capability; (2) two-phase (gas and liquid, foam etc.) capability; (3) cuttings injection and removal system; (4) drill pipe rotation system; and (5) drilling section elevation system. In parallel with the flow loop construction, hydraulics and cuttings transport studies were preformed using drilling foams and aerated muds. In addition, hydraulics and rheology of synthetic drilling fluids were investigated. The studies were performed under ambient and EPET conditions. The effects of temperature and pressure on the hydraulics and cuttings transport were investigated. Mechanistic models were developed to predict frictional pressure loss and cuttings transport in horizontal and near-horizontal configurations. Model predictions were compared with the measured data. Predominantly, model predictions show satisfactory agreements with the measured data. As a

{sup 1}H-NMR and charge transport in metallic polypyrrole at ultra-low temperatures and high magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Jugeshwar Singh, K; Ramesh, K P; Menon, Reghu [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Clark, W G [Department of Physics and Astronomy, University of California at Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States)], E-mail: jshwar@physics.iisc.ernet.in

2008-11-19

The temperature dependence of conductivity, proton spin relaxation time (T{sub 1}) and magnetoconductance (MC) in metallic polypyrrole (PPy) doped with PF{sub 6}{sup -} have been carried out at mK temperatures and high magnetic fields. At T<1 K both electron-electron interaction (EEI) and hopping contributes to conductivity. The temperature dependence of a proton T{sub 1} is classified in three regimes: (a) for T<6 K-relaxation mechanism follows a modified Korringa relation due to EEI and disorder, (b) for 6 K50 K-relaxation is due to the dipolar interaction modulated by the reorientation of the symmetric PF{sub 6} groups following the Bloembergen, Purcell and Pound (BPP) model. The data analysis shows that the Korringa ratio is enhanced by an order of magnitude. The positive and negative MC at T<250 mK is due to the contributions from weak localization and Coulomb-correlated hopping transport, respectively. The role of EEI is observed to be consistent in conductivity, T{sub 1} and MC data, especially at T<1 K.

Electronic transport in VO2—Experimentally calibrated Boltzmann transport modeling

International Nuclear Information System (INIS)

Kinaci, Alper; Rosenmann, Daniel; Chan, Maria K. Y.; Kado, Motohisa; Ling, Chen; Zhu, Gaohua; Banerjee, Debasish

2015-01-01

Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO 2 has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO 2 in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO 2 films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties

Gas-phase transport of fission products

International Nuclear Information System (INIS)

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

1982-01-01

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

Topological transport from a black hole

Directory of Open Access Journals (Sweden)

Dmitry Melnikov

2018-03-01

Full Text Available In this paper the low temperature zero-frequency transport in a 2+1-dimensional theory dual to a dyonic black hole is discussed. It is shown that transport exhibits topological features: the transverse electric and heat conductivities satisfy the Wiedemann–Franz law of free electrons; the direct heat conductivity is measured in units of the central charge of CFT2+1, while the direct electric conductivity vanishes; the thermoelectric conductivity is non-zero at vanishing temperature, while the O(T behavior, controlled by the Mott relation, is subleading. Provided that the entropy of the black hole, and the dual system, is non-vanishing at T=0, the observations indicate that the dyonic black hole describes a ħ→0 limit of a highly degenerate topological state, in which the black hole charge measures the density of excited non-abelian quasiparticles. The holographic description gives further evidence that non-abelian nature of quasiparticles can be determined by the low temperature behavior of the thermoelectric transport.

ECRH and electron heat transport in tokamaks

International Nuclear Information System (INIS)

Zou, X.L.; Giruzzi, G.; Dumont, R.J.

2003-01-01

It has been observed during the ECRH experiments in tokamaks that the shape of the electron temperature profile in stationary regimes is not very sensitive to the ECRH power deposition i.e. the temperature profile remains peaked at the center even though the ECRH power deposition is off-axis. Various models have been invoked for the interpretation of this profile resilience phenomenon: the inward heat pinch, the critical temperature gradient, the Self-Organized Criticality, etc. Except the pinch effect, all of these models need a specific form of the diffusivity in the heat transport equation. In this work, our approach is to solve a simplified time-dependent heat transport equation analytically in cylindrical geometry. The features of this analytical solution are analyzed, in particular the relationship between the temperature profile resilience and the Eigenmode of the physical system with respect to the heat transport phenomenon. Finally, applications of this analytical solution for the determination of the transport coefficient and the polarization of the EC waves are presented. It has been shown that the solution of the simplified transport equation in a finite cylinder is a Fourier-Bessel series. This series represents in fact a decomposition of the heat source in Eigenmode, which are characterized by the Bessel functions of order 0. The physical interpretation of the Eigenmodes is the following: when the heat source is given by a Bessel function of order 0, the temperature profile has exactly the same form as the source at every time. At the beginning of the power injection, the effectiveness of the temperature response is the same for each Eigenmode, and the response in temperature, having the same form as the source, is local. Conversely, in the later phase of the evolution, the effectiveness of the temperature response for each Eigenmode is different: the higher the order, the lower the effectiveness. In this case the response in temperature appears as

Optimizing Stellarators for Turbulent Transport

International Nuclear Information System (INIS)

Mynick, H.E.; Pomphrey, N.; Xanthopoulos, P.

2010-01-01

Up to now, the term 'transport-optimized' stellarators has meant optimized to minimize neoclassical transport, while the task of also mitigating turbulent transport, usually the dominant transport channel in such designs, has not been addressed, due to the complexity of plasma turbulence in stellarators. Here, we demonstrate that stellarators can also be designed to mitigate their turbulent transport, by making use of two powerful numerical tools not available until recently, namely gyrokinetic codes valid for 3D nonlinear simulations, and stellarator optimization codes. A first proof-of-principle configuration is obtained, reducing the level of ion temperature gradient turbulent transport from the NCSX baseline design by a factor of about 2.5.

Charge Transport in LDPE Nanocomposites Part II—Computational Approach

Directory of Open Access Journals (Sweden)

Anh T. Hoang

2016-03-01

Full Text Available A bipolar charge transport model is employed to investigate the remarkable reduction in dc conductivity of low-density polyethylene (LDPE based material filled with uncoated nanofillers (reported in the first part of this work. The effect of temperature on charge transport is considered and the model outcomes are compared with measured conduction currents. The simulations reveal that the contribution of charge carrier recombination to the total transport process becomes more significant at elevated temperatures. Among the effects caused by the presence of nanoparticles, a reduced charge injection at electrodes has been found as the most essential one. Possible mechanisms for charge injection at different temperatures are therefore discussed.

Research and Development for Robotic Transportable Waste to Energy System (TWES)

Science.gov (United States)

2012-01-01

Feedmiser package - 100-gal duplex Feedmiser package, including two hp Grundfos pumps rated to 15 gpm at 602 ft of head and a 100-gal tank The...observed. This was possibly from a bad weld between the back plate and a fire tube, or a leak from a tube itself. This problem warrants further...for damages (to be inserted where spool piece resides on 2” MPS header) Completed • Inspect welds on pipe supports and boiler Completed TWES

Paleoclassical electron heat transport

International Nuclear Information System (INIS)

Callen, J.D.

2005-01-01

Radial electron heat transport in low collisionality, magnetically-confined toroidal plasmas is shown to result from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature equilibrates along magnetic field lines a long length L, which is the minimum of the electron collision length and a maximum effective half length of helical field lines. Thus, the diffusing field lines induce a radial electron heat diffusivity M ≅ L/(πR 0q ) ∼ 10 >> 1 times the magnetic field diffusivity η/μ 0 ≅ ν e (c/ω p ) 2 . The paleoclassical electron heat flux model provides interpretations for many features of 'anomalous' electron heat transport: magnitude and radial profile of electron heat diffusivity (in tokamaks, STs, and RFPs), Alcator scaling in high density plasmas, transport barriers around low order rational surfaces and near a separatrix, and a natural heat pinch (or minimum temperature gradient) heat flux form. (author)

Transport simulations TFTR: Theoretically-based transport models and current scaling

International Nuclear Information System (INIS)

Redi, M.H.; Cummings, J.C.; Bush, C.E.; Fredrickson, E.; Grek, B.; Hahm, T.S.; Hill, K.W.; Johnson, D.W.; Mansfield, D.K.; Park, H.; Scott, S.D.; Stratton, B.C.; Synakowski, E.J.; Tang, W.M.; Taylor, G.

1991-12-01

In order to study the microscopic physics underlying observed L-mode current scaling, 1-1/2-d BALDUR has been used to simulate density and temperature profiles for high and low current, neutral beam heated discharges on TFTR with several semi-empirical, theoretically-based models previously compared for TFTR, including several versions of trapped electron drift wave driven transport. Experiments at TFTR, JET and D3-D show that I p scaling of τ E does not arise from edge modes as previously thought, and is most likely to arise from nonlocal processes or from the I p -dependence of local plasma core transport. Consistent with this, it is found that strong current scaling does not arise from any of several edge models of resistive ballooning. Simulations with the profile consistent drift wave model and with a new model for toroidal collisionless trapped electron mode core transport in a multimode formalism, lead to strong current scaling of τ E for the L-mode cases on TFTR. None of the theoretically-based models succeeded in simulating the measured temperature and density profiles for both high and low current experiments

Non-isothermal Moisture Transport Through Insulation Materials

DEFF Research Database (Denmark)

Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

2008-01-01

An experimental investigation was conducted in order to draw some conclusions on the magnitude of moisture transport due to temperature gradient on a range of porous light-weight building materials. A special constructed non-isothermal set-up allowed the creation of a temperature gradient of 10K...... and given humidity gradient over the sample. The resulting moisture ux as well as the hygrothermal states around and within the material were monitored. The hypothesis of relative humidity being a driving force for non-isothermal moisture transport already in the hygroscopic range could not be confirmed....... On the contrary, indications exist that the temperature gradient itself is driving the moisture from the warm side towards the cold side. An attempt to identify and quantify the single contributions of the different transport forms involved is also presented. The diferent results gave, however, diverging...

Effect of temperature oscillation on thermal characteristics of an aluminum thin film

Science.gov (United States)

Ali, H.; Yilbas, B. S.

2014-12-01

Energy transport in aluminum thin film is examined due to temperature disturbance at the film edge. Thermal separation of electron and lattice systems is considered in the analysis, and temperature variation in each sub-system is formulated. The transient analysis of frequency-dependent and frequency-independent phonon radiative transport incorporating electron-phonon coupling is carried out in the thin film. The dispersion relations of aluminum are used in the frequency-dependent analysis. Temperature at one edge of the film is oscillated at various frequencies, and temporal response of phonon intensity distribution in the film is predicted numerically using the discrete ordinate method. To assess the phonon transport characteristics, equivalent equilibrium temperature is introduced. It is found that equivalent equilibrium temperature in the electron and lattice sub-systems oscillates due to temperature oscillation at the film edge. The amplitude of temperature oscillation reduces as the distance along the film thickness increases toward the low-temperature edge of the film. Equivalent equilibrium temperature attains lower values for the frequency-dependent solution of the phonon transport equation than that corresponding to frequency-independent solution.

On the diffusive nature of W7-AS transport

International Nuclear Information System (INIS)

Stroth, U.; Giannone, L.; Erckmann, V.; Geist, T.; Hartfuss, H.J.; Jaenicke, R.; Kuehner, G.; Ringler, H.; Sardei, F.

1993-01-01

Particle and energy transport in W7-AS have many aspects which are in qualitative agreement with diffusive transport mechanisms. Unlike in tokamaks, the density profiles are flat in the source-free region and for the electron temperature no profile resilience is observed. A strong dependence of transport on the temperature gradient could be ruled out since agreement between the transport coefficients from steady state and perturbative studies has been observed both, in absolute value and parameter dependences. Furthermore, W7-AS transport was found to be compatible with a gyro-Bohm-like and, hence, local transport model. Similar to tokamaks, however, there are problems in relating the local transport coefficients to local plasma parameters. Especially the degradation of confinement with heating power cannot easily be connected to a local quantity. This difficulty is the subject of this paper. (orig.)

The low temperature specific heat and electrical transport, magnetic properties of Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Han, Zhiyong, E-mail: zyhan@cauc.edu.cn

2017-02-01

The magnetic properties, electrical transport properties, and low temperature specific heat of polycrystalline perovskite manganese oxide Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3} have been investigated experimentally. It is found that there exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state and the Debye temperature decreases gradually. In addition, the low temperature electron specific heat in zero magnetic field is obviously larger than that of ordinary rare-earth manganites oxide and this phenomenon is related to the itinerant electrons in ferromagnetic cluster state and the disorder in Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}. - Highlights: • There exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. • With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state. • Low temperature electron specific heat in zero magnetic field is larger than that of ordinary rare-earth manganites oxide.

Provision of servo-controlled cooling during neonatal transport.

Science.gov (United States)

Johnston, Ewen D; Becher, Julie-Clare; Mitchell, Anne P; Stenson, Benjamin J

2012-09-01

Therapeutic hypothermia is a time critical intervention for infants who have experienced a hypoxic-ischaemic event. Previously reported methods of cooling during transport do not demonstrate the same stability achieved in the neonatal unit. The authors developed a system which allowed provision of servo-controlled cooling throughout transport, and present their first year's experience. Retrospective review of routinely collected patient data. 14 out-born infants were referred for cooling during a 12-month period. Nine infants were managed with the servo-controlled system during transport. Cooling was commenced in all infants before 6 h of life. Median time from team arrival to the infant having a temperature in the target range (33-34°C) was 45 min. Median temperature during transfer was 33.5°C (range 33-34°C). Temperature on arrival at the cooling centre ranged from 33.4°C to 33.8°C. Servo-controlled cooling during transport is feasible and provides an optimal level of thermal control.

Gothic simulation of single-channel fuel heatup following a loss of forced flow

Energy Technology Data Exchange (ETDEWEB)

Chen, X-Q; Tahir, A. [NSS, Dept. of Thermal Hydraulics Analysis, Toronto, Ontario (Canada); Parlatan, Y. [Ontario Power Generation, NSATD, Pickering, Ontario (Canada); Kwee, M. [Bruce Power, NSASD, Toronto, Ontario (Canada)

2011-07-01

GOTHIC v7.2 was used to develop a computer model for the simulation of 28- and 37-element fuel heat-up at a loss of forced flow. The model has accounted for the non-uniformity of both axial and radial power distributions along the fuel channel for a typical CANDU reactor. In addition, the model has also accounted for the fuel rods, end-fittings, feeders and headers. Experimental test conditions for both 28- and 37-element bundles at either low or high powers were used for model validation. GOTHIC predictions of the rod and/or pressure-tube temperatures at a variety of test locations were compared with the corresponding experimental measurements. It is found that the numerical results agree well with the experimental measurements for most of the test locations. Results have also shown that the channel venting time is sensitive to the initial temperature distribution in the feeders and headers. An imposed temperature asymmetry at the beginning will cause the channel flow to vent earlier. (author)

Study of the Cooldown and Warmup for the Eight Sectors of the Large Hadron Collider

CERN Document Server

Liu, L; Tavian, L

2004-01-01

The LHC cryogenic system is based on a five-point feed scheme with eight refrigerators serving the eight sectors of the LHC machine. The paper presents the simplified flow scheme of the eight sectors and the mathematical methods including the program flowchart and the boundary conditions to simulate the cooldown and warmup of these sectors. The methods take into account the effect of the pressure drop across the valves as well as the pressure evolution in the different headers of the cryogenic distribution line. The simulated pressure and temperature profiles of headers of the LHC sector during the cooldown and warmup are given and the temperature evolutions of entire processes of cooldown and warmup are presented. As a conclusion, the functions of the input temperature for the normal and fast cooldown and warmup, the cooldown and warmup time of each sector and the distributions of mass flow rates in each sector are summarized. The results indicate that it is possible to cool down any of the LHC sector within...

Electrical transport properties of V2O5 thin films obtained by thermal annealing of layers grown by RF magnetron sputtering at room temperature

International Nuclear Information System (INIS)

Giannetta, H.M.R.; Calaza, C.; Lamas, D.G.; Fonseca, L.; Fraigi, L.

2015-01-01

The present study investigates the main electrical transport mechanism in V 2 O 5 thin films deposited by RF magnetron sputtering on the basis of the Mott's small polaron hopping model. The material under test was obtained at room temperature from a V 2 O 5 target and then oxidized at high temperature under air atmosphere to obtain the desired V 2 O 5 phase. The dependence of the electrical conductivity of the V 2 O 5 thin films with temperature was analyzed using the Mott's small polarons hopping transport model under the Schnakenberg form. Model results suggest a polaron binding energy W H = 0.1682 eV, with a structural disorder energy W D = 0.2241 eV and an optical phonon frequency ν 0 = 0.468 × 10 13 s −1 . These results are in agreement with data reported in literature for single crystal V 2 O 5 . However, the carrier mobility μ = 1.5019 × 10 −5 cm 2 /Vs computed in the non-adiabatic regime is significantly smaller than that of the single crystal, suggesting a strong electron–phonon coupling in the V 2 O 5 thin films obtained with the proposed deposition method. - Highlights: • A two-stage deposition method compatible with lift-off patterning is proposed. • V 2 O 5 films are deposited by RF magnetron sputtering and then annealed in air. • Films are analyzed by SEM and its pure phase nature is confirmed by XRD. • Electrical conductivity was fitted using Mott's model for small polarons. • Fit derived parameters confirm charge transport through small-polarons hopping

Temperature effects on the Davydov soliton

DEFF Research Database (Denmark)

Cruzeiro, L.; Halding, J.; Christiansen, Peter Leth

1988-01-01

As a possible mechanism for energy storage and transport in proteins, Davydov has proposed soliton formation and propagation. In this paper we investigate the stability of Davydov solitons at biological temperatures. From Davydov’s original theory evolution equations are derived quantum mechanica......As a possible mechanism for energy storage and transport in proteins, Davydov has proposed soliton formation and propagation. In this paper we investigate the stability of Davydov solitons at biological temperatures. From Davydov’s original theory evolution equations are derived quantum...

Effect of annealing temperature on the electrical transport properties of CaRuO3-δ thin films directly deposited on the Si substrate

International Nuclear Information System (INIS)

Paik, Hanjong; Kim, Youngha; No, Kwangsoo; Cann, David P.; Yoon, DongJoo; Kim, ByungIl; Kim, Yangsoo

2007-01-01

We investigate the effect of annealing temperature on the preferentially (110)-oriented CaRuO 3-δ (CRO) thin films directly prepared on Si(100) substrate by rf magnetron sputtering. Crystalline quality and electrical transport properties of the CRO thin films were modified by post-annealing treatment. It was obvious that 700 C post-annealing brought about excellent metallic characteristics with the elevation of carrier concentration and mobility. From this result, we suggested that enhanced (110) orientation, and the ratio of chemical composition Ru 4+ /Ca 2+ ion were responsible for the transport properties of CRO thin film. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

Energy Technology Data Exchange (ETDEWEB)

Vo, Truong Quoc; Kim, BoHung, E-mail: muratbarisik@iyte.edu.tr, E-mail: bohungk@ulsan.ac.kr [School of Mechanical Engineering, University of Ulsan, Daehak-ro 93, Namgu, Ulsan 680-749 (Korea, Republic of); Barisik, Murat, E-mail: muratbarisik@iyte.edu.tr, E-mail: bohungk@ulsan.ac.kr [Department of Mechanical Engineering, Izmir Institute of Technology, Urla, Izmir 35430 (Turkey)

2016-05-21

This study focuses on the proper characterization of temperature profiles across grain boundaries (GBs) in order to calculate the correct interfacial thermal resistance (ITR) and reveal the influence of GB geometries onto thermal transport. The solid-solid interfaces resulting from the orientation difference between the (001), (011), and (111) copper surfaces were investigated. Temperature discontinuities were observed at the boundary of grains due to the phonon mismatch, phonon backscattering, and atomic forces between dissimilar structures at the GBs. We observed that the temperature decreases gradually in the GB area rather than a sharp drop at the interface. As a result, three distinct temperature gradients developed at the GB which were different than the one observed in the bulk solid. This behavior extends a couple molecular diameters into both sides of the interface where we defined a thickness at GB based on the measured temperature profiles for characterization. Results showed dependence on the selection of the bin size used to average the temperature data from the molecular dynamics system. The bin size on the order of the crystal layer spacing was found to present an accurate temperature profile through the GB. We further calculated the GB thickness of various cases by using potential energy (PE) distributions which showed agreement with direct measurements from the temperature profile and validated the proper binning. The variation of grain crystal orientation developed different molecular densities which were characterized by the average atomic surface density (ASD) definition. Our results revealed that the ASD is the primary factor affecting the structural disorders and heat transfer at the solid-solid interfaces. Using a system in which the planes are highly close-packed can enhance the probability of interactions and the degree of overlap between vibrational density of states (VDOS) of atoms forming at interfaces, leading to a reduced ITR. Thus, an

Surface transport in plasma-balls

Energy Technology Data Exchange (ETDEWEB)

Armas, Jay [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Bhattacharya, Jyotirmoy [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Kundu, Nilay [Harish-Chandra Research Institute,Chhatnag Road, Jhunsi, Allahabad 211019 (India)

2016-06-06

We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an application, we study the effect of temperature dependence of surface tension on some explicit examples of localized fluid configurations, which are dual to certain non-trivial black hole solutions via the AdS/CFT correspondence.

Low temperature transport in p-doped InAs nanowires

DEFF Research Database (Denmark)

Upadhyay, Shivendra; Jespersen, Thomas Sand; Madsen, Morten Hannibal

2013-01-01

We present low temperature electrical measurements of p-type Indium Arsenide nanowires grown via molecular beam epitaxy using Beryllium as a dopant. Growth of p-type wires without stacking faults is demonstrated. Devices in field-effect geometries exhibit ambipolar behavior, and the temperature...

Fuel cell water transport

Science.gov (United States)

Vanderborgh, Nicholas E.; Hedstrom, James C.

1990-01-01

The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidify a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.

Design, Implementation and Evaluation of an Operating System for a Network of Transputers.

Science.gov (United States)

1987-06-01

WHILE TRUE -- listen to linki SEQ receiving the header BYTE.SLICE.INPUT (linkl,headerl,1,header.size) -- decoding the block size block.sizelLO] z...I’m done BYTE.SLICE.OUTPUT (screen[0] ,header0,3,1) WHILE TRUE -- listen to linki SEQ- rec eiving the header BYTE.SLICE. IPUT (linkl,headerl,1

On the diffusive nature of W7-AS transport

Energy Technology Data Exchange (ETDEWEB)

Stroth, U; Giannone, L.; Erckmann, V; Geist, T; Hartfuss, H J; Jaenicke, R; Kuehner, G; Ringler, H; Sardei, F [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

1994-12-31

Particle and energy transport in W7-AS have many aspects which are in qualitative agreement with diffusive transport mechanisms. Unlike in tokamaks, the density profiles are flat in the source-free region and for the electron temperature no profile resilience is observed. A strong dependence of transport on the temperature gradient could be ruled out since agreement between the transport coefficients from steady state and perturbative studies has been observed both, in absolute value and parameter dependences. Furthermore, W7-AS transport was found to be compatible with a gyro-Bohm-like and, hence, local transport model. Similar to tokamaks, however, there are problems in relating the local transport coefficients to local plasma parameters. Especially the degradation of confinement with heating power cannot easily be connected to a local quantity. This difficulty is the subject of this paper. (author) 2 refs., 4 figs.

On the diffusive nature of W7-AS transport

International Nuclear Information System (INIS)

Stroth, U.; Giannone, L.; Erckmann, V.; Geist, T.; Hartfuss, H.J.; Jaenicke, R.; Kuehner, G.; Ringler, H.; Sardei, F.

1993-01-01

Particle and energy transport in W7-AS have many aspects which are in qualitative agreement with diffusive transport mechanisms. Unlike in tokamaks, the density profiles are flat in the source-free region and for the electron temperature no profile resilience is observed. A strong dependence of transport on the temperature gradient could be ruled out since agreement between the transport coefficients from steady state and perturbative studies has been observed both, in absolute value and parameter dependences. Furthermore, W7-AS transport was found to be compatible with a gyro-Bohm-like and, hence, local transport model. Similar to tokamaks, however, there are problems in relating the local transport coefficients to local plasma parameters. Especially the degradation of confinement with heating power cannot easily be connected to a local quantity. This difficulty is the subject of this paper. (author) 2 refs., 4 figs

Transport due to ion temperature gradient mode vortex turbulence

International Nuclear Information System (INIS)

Pavlenko, V.P.; Weiland, J.

1991-01-01

The ion energy transport due to an ensemble of nonlinear vortices is calculated in the test particle approximation for a strongly turbulent plasma. A diffusion coefficient proportional to the root of the stationary turbulence level is obtained. (au)

The temperature distribution in a gas core fission reactor

Energy Technology Data Exchange (ETDEWEB)

Hoogenboom, J.E.; Dam, H. van; Kuijper, J.C. (Interuniversitair Reactor Inst., Delft (Netherlands)); Kistemaker, J.; Boersma-Klein, W.; Vitalis, F. (FOM-Instituut voor Atoom-en Molecuulfysica, Amsterdam (Netherlands))

1991-01-01

A model is proposed for the heat transport in a nuclear reactor with gaseous fuel at high temperatures taking into account radiative and kinetic heat transfer. A derivation is given of the equation determining the temperature distribution in a gas core reactor and different numerical solution methods are discussed in detail. Results are presented of the temperature distribution. The influence of the kinetic heat transport and of dissociation of the gas molecules is shown. Also discussed is the importance of the temperature gradient at the reactor wall and its dependence on system parameters. (author).

The temperature distribution in a gas core fission reactor

International Nuclear Information System (INIS)

Hoogenboom, J.E.; Dam, H. van; Kuijper, J.C.; Kistemaker, J.; Boersma-Klein, W.; Vitalis, F.

1991-01-01

A model is proposed for the heat transport in a nuclear reactor with gaseous fuel at high temperatures taking into account radiative and kinetic heat transfer. A derivation is given of the equation determining the temperature distribution in a gas core reactor and different numerical solution methods are discussed in detail. Results are presented of the temperature distribution. The influence of the kinetic heat transport and of dissociation of the gas molecules is shown. Also discussed is the importance of the temperature gradient at the reactor wall and its dependence on system parameters. (author)

Recognition of VLSI Module Isomorphism

Science.gov (United States)

1990-03-01

forthforth->next; 6.5 else{ prev4=prev4->next; forth=forth->next; if (header-. nenI ->tai==third){ header-.nevrI->tail=prev3; prev3->next=NULL; end...end=TRUE; if (header-. nenI ->head=third){ header-.newn->head=third->next; I if((third!=prev3)&&(finished!=TRUE)){ prev3->next=prev3->next->next; third

Energy and particle core transport in tokamaks and stellarators compared

Energy Technology Data Exchange (ETDEWEB)

Beurskens, Marc; Angioni, Clemente; Beidler, Craig; Dinklage, Andreas; Fuchert, Golo; Hirsch, Matthias; Puetterich, Thomas; Wolf, Robert [Max-Planck-Institut fuer Plasmaphysik, Greifswald/Garching (Germany)

2016-07-01

The paper discusses expectations for core transport in the Wendelstein 7-X stellarator (W7-X) and presents a comparison to tokamaks. In tokamaks, the neoclassical trapped-particle-driven losses are small and turbulence dominates the energy and particle transport. At reactor relevant low collisionality, the heat transport is limited by ion temperature gradient limited turbulence, clamping the temperature gradient. The particle transport is set by an anomalous inward pinch, yielding peaked profiles. A strong edge pedestal adds to the good confinement properties. In traditional stellarators the 3D geometry cause increased trapped orbit losses. At reactor relevant low collisionality and high temperatures, these neoclassical losses would be well above the turbulent transport losses. The W7-X design minimizes neoclassical losses and turbulent transport can become dominant. Moreover, the separation of regions of bad curvature and that of trapped particle orbits in W7-X may have favourable implications on the turbulent electron heat transport. The neoclassical particle thermodiffusion is outward. Without core particle sources the density profile is flat or even hollow. The presence of a turbulence driven inward anomalous particle pinch in W7-X (like in tokamaks) is an open topic of research.

Influence of hole transport material/metal contact interface on perovskite solar cells

Science.gov (United States)

Lei, Lei; Zhang, Shude; Yang, Songwang; Li, Xiaomin; Yu, Yu; Wei, Qingzhu; Ni, Zhichun; Li, Ming

2018-06-01

Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions. High incident kinetic energy metal particles were proved to penetrate and embed into the hole transport material. These isolated metal particles in hole transport materials capture holes and increase the apparent carrier transport resistance of the hole transport layer. Sample temperature was found to be of great significance in metal deposition. Since metal vapour has a high temperature, the deposition process accumulated a large amount of heat. The heat evaporated the additives in the hole transport layer and decreased the hole conductivity. On the other hand, high temperature may cause iodization of the metal contact.

Magneto Transport of CVD Carbon in Artificial Opals

Science.gov (United States)

Wang, Lei; Yin, Ming; Arammash, Fauzi; Datta, Timir

2014-03-01

Magneto-transport of carbon inverse opal structures were investigated in the 2.5 to 300 K temperatures and magnetic fields in the 0-10T regime. Qualitatively, our observations lie between those reported by previous researchers. Over this temperature range, transport (in zero magnetic field) is non-metallic; the resistance decreased with rising temperature however the temperature dependent behavior is not activated, as observed with variable range hopping. In three-dimensions, such behavior can also be the result of weak localization and electron-electron interactions; in particular the change in conductivity is a polynomial in fractional powers of absolute temperature. At sub-helium temperature regimes the relative magneto resistance is measured to be ~ 0.1 percent per Tesla. Results of data analysis for several different scenarios will be reported. DOD award #60177-RT-H from the ARO.

Loss of coolant analysis for CIRENE-LATINA heavy water reactor

International Nuclear Information System (INIS)

Chiantore, B.; Dubbini, M.; Proto, G.

1978-01-01

CIRENE is a heavy-water moderated, boiling water cooled pressure tube reactor. Fuel is natural uranium. A variety of breaks in the primary coolant system have been postulated for the analysis of the CIRENE Latina Plant (now under construction) such as double-end break of inlet header, downcomer, steam line and inlet feeders. The basic tool for analysis is the TILT-N Code which has been purposely developed for simulating the nuclear, thermal and hydrodynamic behaviour of the CIRENE core and associated heat transport system. An extensive full-scale test programme has been carried out by CNEN and CISE which fully confirms the adequacy of the model. The main results of the analysis show that maximum temperatures are far from those leading to significant fuel damage and that adequate core cooling is provided over the whole transient. (author)

Transition phenomena and thermal transport properties in LHD plasmas with an electron internal transport barrier

International Nuclear Information System (INIS)

Shimozuma, T.; Kubo, S.; Idei, H.; Inagaki, S.; Tamura, N.; Tokuzawa, T.; Morisaki, T.; Watanabe, K.Y.; Ida, K.; Yamada, I.; Narihara, K.; Muto, S.; Yokoyama, M.; Yoshimura, Y.; Notake, T.; Ohkubo, K.; Seki, T.; Saito, K.; Kumazawa, R.; Mutoh, T.; Watari, T.; Komori, A.

2005-01-01

Two types of improved core confinement were observed during centrally focused electron cyclotron heating (ECH) into plasmas sustained by counter (CNTR) and Co neutral beam injections (NBI) in the Large Helical Device. The CNTR NBI plasma displayed transition phenomena to the high-electron-temperature state and had a clear electron internal transport barrier, while the Co NBI plasma did not show a clear transition or an ECH power threshold but showed broad high temperature profiles with moderate temperature gradient. This indicated that the Co NBI plasma with additional ECH also had an improved core confinement. The electron heat transport characteristics of these plasmas were directly investigated using heat pulse propagation excited by modulated ECH. These effects appear to be related to the m/n = 2/1 rational surface or the island induced by NBI beam-driven current

Turbulence and anomalous transport in toroidal plasmas

International Nuclear Information System (INIS)

Nordman, H.

1989-01-01

In present-day Tokamak fusion machines, instabilities and turbulence driven by temperature gradients can have a considerable impact on the confinement qualities. This thesis is mainly devoted to analyzing the nonlinear evolution of these instabilities and the associated turbulent transport. A combined analytical and numerical study of the ion temperature gradient driven turbulence is presented. An analytical expression for the ion thermal conductivity is derived and found to be in good agreement with the simulation results. The scaling properties of chi i are investigated and compared with experimental results. The transport due to the simultaneous presence of a trapped electron mode and an ion temperature gradient mode is analysed. It is found that the coupling of the modes can give rise to inward diffusive fluxes of both particles and energy. The tendency of the system to equilibrate density and temperature scale lengths is compared with recent experimental trends. The nonlinear behaviour of the instabilities is also studied in the context of low dimensional dynamical systems. Here, the relation between the fully nonlinear fluid models and the low dimensional models is discussed. The influence of a high frequency RF-field on the ion temperature gradient driven mode is investigated analytically. The consequences for mode stability and transport are considered. 23 refs

Turbulence and anomalous transport in toroidal plasmas

Energy Technology Data Exchange (ETDEWEB)

Nordman, H

1990-12-31

In present-day Tokamak fusion machines, instabilities and turbulence driven by temperature gradients can have a considerable impact on the confinement qualities. This thesis is mainly devoted to analyzing the nonlinear evolution of these instabilities and the associated turbulent transport. A combined analytical and numerical study of the ion temperature gradient driven turbulence is presented. An analytical expression for the ion thermal conductivity is derived and found to be in good agreement with the simulation results. The scaling properties of chi{sub i} are investigated and compared with experimental results. The transport due to the simultaneous presence of a trapped electron mode and an ion temperature gradient mode is analysed. It is found that the coupling of the modes can give rise to inward diffusive fluxes of both particles and energy. The tendency of the system to equilibrate density and temperature scale lengths is compared with recent experimental trends. The nonlinear behaviour of the instabilities is also studied in the context of low dimensional dynamical systems. Here, the relation between the fully nonlinear fluid models and the low dimensional models is discussed. The influence of a high frequency RF-field on the ion temperature gradient driven mode is investigated analytically. The consequences for mode stability and transport are considered. 23 refs.

Dual-temperature acoustic levitation and sample transport apparatus

Science.gov (United States)

Trinh, E.; Robey, J.; Jacobi, N.; Wang, T.

1986-01-01

The properties of a dual-temperature resonant chamber to be used for acoustical levitation and positioning have been theoretically and experimentally studied. The predictions of a first-order dissipationless treatment of the generalized wave equation for an inhomogeneous medium are in close agreement with experimental results for the temperature dependence of the resonant mode spectrum and the acoustic pressure distribution, although the measured magnitude of the pressure variations does not correlate well with the calculated one. Ground-based levitation of low-density samples has been demonstrated at 800 C, where steady-state forces up to 700 dyn were generated.

11th Magdeburg seminar on waters in Central and Eastern Europe: Assessment, protection, management. Proceedings

International Nuclear Information System (INIS)

Geller, W.

2004-01-01

The meeting was held October 2004 in Leipzig. The 148 contributions and lectures were pooled under the following session headers: Ecological impacts of flooding, flood risk modelling, socio-economic issues of water framework directive, Nitrogen-transport, methods development,sediments, flood protection and Mitigation, flood risk management, draughts, pollutants impact, integrated assessment, transboundary problems, groundwater, land use, modelling and plankton, fish biota. (uke)

Award of merit: transportable remediation unit -Jacques Whitford Environment Limited -Toronto

International Nuclear Information System (INIS)

Anon.

1995-01-01

A unique hybrid of remediation technologies was designed to deal with the problem of removing the gasoline and fuel-oil found in soils and groundwater as a result of spills or leakage at petroleum storage and dispensing facilities. Liquid petroleum hydrocarbons were found discharging into a creek in a residential and commercial neighborhood of Metropolitan Toronto. Numerous in-place soil and ground water remediation approaches were evaluated in the course of searching for a solution. A full-scale, transportable, in-situ bioslurping remediation unit was recommended. The unit was connected to 13 specially designed vertical bioslurping wells, and to a buried horizontal header network comprised of four separate zones that could be used to simultaneously extract and/or inject air and water flows. Cycling of various modes of operation was based on detailed monitoring and analysis, which allowed for optimal recovery and biological degradation of contaminants. After only four months of operation, over 4000 kg of petroleum hydrocarbon contaminants had been removed and treated, and all of the mobile liquid hydrocarbons at the water table had been removed. Treatment cost was estimated at $100 to $120 per tonne of contaminated soil, but assuming that the unit could be used at more than one site, the net treatment cost would decrease to $20 to $30 per tonne. 1 ill

Temperature dependent transport characteristics of graphene/n-Si diodes

NARCIS (Netherlands)

Parui, S.; Ruiter, R.; Zomer, P. J.; Wojtaszek, M.; van Wees, B. J.; Banerjee, T.

2014-01-01

Realizing an optimal Schottky interface of graphene on Si is challenging, as the electrical transport strongly depends on the graphene quality and the fabrication processes. Such interfaces are of increasing research interest for integration in diverse electronic devices as they are thermally and

Detection and evaluation of corrosion zones at high temperature in steam generators; Deteccion y evaluacion de zonas de corrosion en alta temperatura de generadoras de vapor

Energy Technology Data Exchange (ETDEWEB)

Martinez Villafane, Alberto; Chacon Nava, Jose G; Huerta Espino, Mario; Mojica Calderon, Cecilio; Castillo Viveros, Antonio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1991-12-31

This paper presents the methodology for the detection and evaluation of high corrosion zones at high temperature. The results found up to now, show a critical zone in the Babcock Hitachi design, specifically in the high temperature reheater in the zone nearby the outlet header. In the normalized design CE (Mitsubishi) of 300 MW and CE (Canada) of 300 MW, the results found in recent years show small thickness reduction, therefore a good operation of these steam generators is recognized. [Espanol] En este trabajo se presenta la metodologia para la deteccion y evaluacion de zonas de corrosion en alta temperatura. Los resultados encontrados hasta el momento muestran una zona critica en el diseno Babcock Hitachi, especificamente en el recalentador de alta temperatura en la zona cercana al cabezal de salida. En el diseno normalizado CE (Mitsubishi) de 300 MW y CE (Canada) de 300 MW, los resultados encontrados en anos recientes muestran poca disminucion de espesor, por lo que se considera una buena operacion de estos generadores de vapor.

Detection and evaluation of corrosion zones at high temperature in steam generators; Deteccion y evaluacion de zonas de corrosion en alta temperatura de generadoras de vapor

Energy Technology Data Exchange (ETDEWEB)

Martinez Villafane, Alberto; Chacon Nava, Jose G.; Huerta Espino, Mario; Mojica Calderon, Cecilio; Castillo Viveros, Antonio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1990-12-31

This paper presents the methodology for the detection and evaluation of high corrosion zones at high temperature. The results found up to now, show a critical zone in the Babcock Hitachi design, specifically in the high temperature reheater in the zone nearby the outlet header. In the normalized design CE (Mitsubishi) of 300 MW and CE (Canada) of 300 MW, the results found in recent years show small thickness reduction, therefore a good operation of these steam generators is recognized. [Espanol] En este trabajo se presenta la metodologia para la deteccion y evaluacion de zonas de corrosion en alta temperatura. Los resultados encontrados hasta el momento muestran una zona critica en el diseno Babcock Hitachi, especificamente en el recalentador de alta temperatura en la zona cercana al cabezal de salida. En el diseno normalizado CE (Mitsubishi) de 300 MW y CE (Canada) de 300 MW, los resultados encontrados en anos recientes muestran poca disminucion de espesor, por lo que se considera una buena operacion de estos generadores de vapor.

On the separation and association of vapour in large power stations; Ueber die Trennung und Vereinigung von Dampf in Grosskraftwerken

Energy Technology Data Exchange (ETDEWEB)

Matschke, Alan

2012-07-01

The main objectives for the improvement of utility boilers are to increase their overall efficiency. Therefore, steam parameters need to be increased leading to temperatures which may exceed the limiting temperatures of the tube materials. Considering these aspects, the single tube temperatures of a powerplant have to be determined to prevent material failure. In order to account for the mutual impact of combustion and water-steam-cycle, a coupled simulation is performed to calculate the single tube temperatures. Apart from the interaction of combustion and water-steam-cycle, the design of the heat exchanger headers is relevant. On the basis of a detailed investigation of the pressure distribution in steam distributors and headers, a new quality regarding the prediction and calculation of single tube temperatures will be obtained. By means of a similarity analysis, the governing geometry relations associated with the pressure change in steam distributors and headers are identified. The parametrisation of this approach is done by comparing the measured pressure values of an air-flow divider-collector-combination. The portability of the air-flow results to water, respectively steam is approved. Based on the experimental data, computational fluid dynamic simulations of all governing geometrical relations are performed. The validity of the similarity based approach is shown for nearly all geometrical relations corresponding to real utility boiler application. Deviations between experiment and calculations based on the similarity approach are only evident for very short distances of separating tubes originating from secondary vortices. However, the impact of these vortices to the global mass distribution is minimal. The comparison between measured and calculated single tube temperatures from a lignite-fired utility boiler shows the good match between the simulated and measured temperatures. The single tube temperatures of a heat exchanger across the boiler width are

Charge transport in organic crystals

Energy Technology Data Exchange (ETDEWEB)

Ortmann, Frank

2009-07-01

The understanding of charge transport is one of the central goals in the research on semiconducting crystals. For organic crystals this is particularly complicated due to the strength of the electron-phonon interaction which requires the description of a seamless transition between the limiting cases of a coherent band-transport mechanism and incoherent hopping. In this thesis, charge transport phenomena in organic crystals are studied by theoretical means. A theory for charge transport in organic crystals is developed which covers the whole temperature range from low T, where it reproduces an expression from the Boltzmann equation for band transport, via elevated T, where it generalizes Holstein's small-polaron theory to finite bandwidths, up to high T, for which a temperature dependence equal to Marcus' electron-transfer theory is obtained. Thereby, coherent band transport and thermally induced hopping are treated on equal footing while simultaneously treating the electron-phonon interaction non-perturbatively. By avoiding the approximation of narrow polaron bands the theory allows for the description of large and small polarons and serves as a starting point for computational studies. The theoretical description is completed by using ab initio material parameters for the selected crystals under study. These material parameters are taken from density functional theory calculations for durene, naphthalene, and guanine crystals. Besides the analysis of the transport mechanism, special focus is put on the study of the relationship between mobility anisotropy and structure of the crystals. This study is supported by a 3D-visualization method for the transport channels in such crystals which has been derived in this thesis. (orig.)

Kinetic neoclassical transport in the H-mode pedestal

Energy Technology Data Exchange (ETDEWEB)

Battaglia, D. J.; Chang, C. S.; Ku, S.; Grierson, B. A. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08540 (United States); Burrell, K. H.; Grassie, J. S. de [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2014-07-15

Multi-species kinetic neoclassical transport through the QH-mode pedestal and scrape-off layer on DIII-D is calculated using XGC0, a 5D full-f particle-in-cell drift-kinetic solver with self-consistent neutral recycling and sheath potentials. Quantitative agreement between the flux-driven simulation and the experimental electron density, impurity density, and orthogonal measurements of impurity temperature and flow profiles is achieved by adding random-walk particle diffusion to the guiding-center drift motion. The radial electric field (E{sub r}) that maintains ambipolar transport across flux surfaces and to the wall is computed self-consistently on closed and open magnetic field lines and is in excellent agreement with experiment. The E{sub r} inside the separatrix is the unique solution that balances the outward flux of thermal tail deuterium ions against the outward neoclassical electron flux and inward pinch of impurity and colder deuterium ions. Particle transport in the pedestal is primarily due to anomalous transport, while the ion heat and momentum transport are primarily due to the neoclassical transport. The full-f treatment quantifies the non-Maxwellian energy distributions that describe a number of experimental observations in low-collisionallity pedestals on DIII-D, including intrinsic co-I{sub p} parallel flows in the pedestal, ion temperature anisotropy, and large impurity temperatures in the scrape-off layer.

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Adler, H.; Bell, M.G.; Bell, R.; Budny, R.V.; Bush, C.E.; Chang, Z.; Duong, H.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ (A) 0.7-0.8 and τ pe (a) ∝ (A) 0.8

Finite temperature dynamics of a Holstein polaron: The thermo-field dynamics approach

Science.gov (United States)

Chen, Lipeng; Zhao, Yang

2017-12-01

Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling. While for weak to moderate diagonal coupling temperature increases inhibit polaron mobility, it is found that off-diagonal coupling induces phonon-assisted transport that dominates at high temperatures. Results on the mean square displacements show that band-like transport features dominate the diagonal coupling cases, and there exists a crossover from band-like to hopping transport with increasing temperature when including off-diagonal coupling. As a proof of concept, our theory provides a unified treatment of coherent and incoherent transport in molecular crystals and is applicable to any temperature.

Thermophilic P-loop transport ATPases : Enzyme function and energetics at high temperature

NARCIS (Netherlands)

Pretz, Monika Gyöngyi

2007-01-01

Primary transport ATPases are divided into several superfamilies; amongst others including ATPases of the ABC transporter superfamily, the F-ATPase superfamily or the motor ATPases of the General Secretory (Sec) pathway. Motor proteins from these superfamilies show a low sequence similarity, except

Edge-core interaction revealed with dynamic transport experiment in LHD

International Nuclear Information System (INIS)

Tamura, N.; Ida, K.; Inagaki, S.

2010-11-01

Large scale coherent structures in electron heat transport of both core and edge plasmas are clearly found in plasma with a nonlocal transport phenomenon (NTP, a core electron temperature rise in response to an edge cooling) on Large Helical Device (LHD). At the onset of the NTP, a first order transition of the electron heat transport, which is characterized by a discontinuity of electron temperature gradient, is found to take place over a wide region (at least 6 cm wide) in the periphery of the plasma. At about the same time, over a wide region (about 10 cm wide) of the plasma core, a second order transition of the electron heat transport, which is characterized by a discontinuity of the time derivative of the electron temperature gradient, appears. The both large scale coherent structures are of a scale larger than a typical micro-turbulent eddy size (a few mm in this case). In order to assess dynamic characteristics of the electron heat transport state in the core region during the NTP, a transit time distribution analysis is applied to the temporal behaviors of the electron temperature gradient. The analysis results more clearly show the existence of the large coherent structures in electron heat transport. Thus the NTP observed in LHD is considered to be invoked by the interaction of those structures. (author)

CHMTRNS, Non-Equilibrium Chemical Transport Code

International Nuclear Information System (INIS)

Noorishad, J.; Carnahan, C.L.; Benson, L.V.

1998-01-01

1 - Description of program or function: CHMTRNS simulates solute transport for steady one-dimensional fluid flow by convection and diffusion or dispersion in a saturated porous medium based on the assumption of local chemical equilibrium. The chemical interactions included in the model are aqueous-phase complexation, solid-phase ion exchange of bare ions and complexes using the surface complexation model, and precipitation or dissolution of solids. The program can simulate the kinetic dissolution or precipitation for calcite and silica as well as irreversible dissolution of glass. Thermodynamic parameters are temperature dependent and are coupled to a companion heat transport simulator; thus, the effects of transient temperature conditions can be considered. Options for oxidation-reduction (redox) and C-13 fractionation as well as non-isothermal conditions are included. 2 - Method of solution: The governing equations for both reactive chemical and heat transport are discretized in time and space. For heat transport, the Crank-Nicolson approximation is used in conjunction with a LU decomposition and backward substitution solution procedure. To deal with the strong nonlinearity of the chemical transport equations, a generalized Newton-Raphson method is used

The Effect of Post-Baking Temperature and Thickness of ZnO Electron Transport Layers for Efficient Planar Heterojunction Organometal-Trihalide Perovskite Solar Cells

Directory of Open Access Journals (Sweden)

Kun-Mu Lee

2017-11-01

Full Text Available Solution-processed zinc oxide (ZnO-based planar heterojunction perovskite photovoltaic device is reported in this study. The photovoltaic device benefits from the ZnO film as a high-conductivity and high-transparent electron transport layer. The optimal electron transport layer thickness and post-baking temperature for ZnO are systematically studied by scanning electron microscopy, photoluminescence and time-resolved photoluminescence spectroscopy, and X-ray diffraction. Optimized perovskite solar cells (PSCs show an open-circuit voltage, a short-circuit current density, and a fill factor of 1.04 V, 18.71 mA/cm2, and 70.2%, respectively. The highest power conversion efficiency of 13.66% was obtained when the device was prepared with a ZnO electron transport layer with a thickness of ~20 nm and when post-baking at 180 °C for 30 min. Finally, the stability of the highest performance ZnO-based PSCs without encapsulation was investigated in detail.

Time temperature indicators as devices intelligent packaging

Directory of Open Access Journals (Sweden)

Adriana Pavelková

2013-01-01

Full Text Available Food packaging is an important part of food production. Temperature is a one of crucial factor which affecting the quality and safety of food products during distribution, transport and storage. The one way of control of food quality and safety is the application of new packaging systems, which also include the intelligent or smart packaging. Intelligent packaging is a packaging system using different indicators for monitoring the conditions of production, but in particular the conditions during transport and storage. Among these indicators include the time-temperature indicators to monitor changes in temperature, which is exposed the product and to inform consumers about the potential risks associated with consumption of these products. Time temperature indicators are devices that show an irreversible change in a physical characteristic, usually color or shape, in response to temperature history. Some are designed to monitor the evolution of temperature with time along the distribution chain and others are designed to be used in the consumer packages.

Elastic scattering and transport coefficients for a quark plasma in SUf(3) at finite temperatures

Science.gov (United States)

Rehberg, P.; Klevansky, S. P.; Hüfner, J.

1996-02-01

The temperature dependence of the elastic-scattering processes qq' → qq' and q overlineq' → q overlineq' , with q, q' = u, d, s is studied as a function of the scattering angle and the center-of-mass energy of the collision within the framework of the SUf(3) Nambu-Jona-Lasinio model. Critical scattering at threshold is observed in the q overlineq' → q overlineq' process, leading to an enhancement of the cross section as occurs in the phenomenon of critical opalescence. Transport properties such as viscosity, mean free paths and thermal relaxation times are calculated. Strangeness enhancement is investigated via the chemical relaxation times, which are found to be considerably higher than those calculated via perturbative QCD. A comparison with the experimental values for the strangeness enhancement in S + S collisions leads to an upper limit of 4 fm/ c for the lifetime of the plasma.

Nanoscale hotspots due to nonequilibrium thermal transport

International Nuclear Information System (INIS)

Sinha, Sanjiv; Goodson, Kenneth E.

2004-01-01

Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

Electrical transport in GaN and InN nanowires; Elektrischer Transport in GaN- und InN-Nanodraehten

Energy Technology Data Exchange (ETDEWEB)

Richter, Thomas Fabian

2008-12-19

This thesis discusses the analysis of the electrical transport in GaN and InN nanowires at room temperature and deep temperatures. From those measurements two different transport models for those two in matter of the band banding completely different materials have been found. In the investigation of the GaN nanowires the main focus was the electrical transport in dependence of the diameter and the n-doping. With the use of IV-measurements on those MBE grown nanowires with different diameters at dark and under UV illumination as well as the decay of the persistent photocurrent, it was possible to find an for GaN untypical behaviour. The electrical transport in those wires is extremely diameter dependent. The dark current shows space charged limited current. With the help of those cognitions a diameter dependent transport model could be found. The transport phenomena in those wires is based on the diameter depending band bending at the edge of the wires caused by the Fermi level pinning inside the forbidden band. This model can be fit to the data with the three parameter doping, fermi level pinning and wire diameter. On the base of those effects a method to determine the doping concentration inside those wires without field effect measurements and contact resistance has been developed. The defect structure inside those wires has been analysed with the help of spectral photoluminescence measurements. Here several defect bands have been found and it was possible with help of several contacts on one single wire to determine different defect regions along the wire and to explain them by the lattice mismatch between nanowire and substrate. Further temperature depending measurements and investigations on Schottky contacted wires as well as on GaN wires with AlN tunnel structures complete the work on GaN. The electrical characterisation on a large scale of undoped and doped InN nanowires shows linear growth of the dark current with the diameter up to wires of around 100 nm

Simulation of electron thermal transport in H-mode discharges

International Nuclear Information System (INIS)

Rafiq, T.; Pankin, A. Y.; Bateman, G.; Kritz, A. H.; Halpern, F. D.

2009-01-01

Electron thermal transport in DIII-D H-mode tokamak plasmas [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated by comparing predictive simulation results for the evolution of electron temperature profiles with experimental data. The comparison includes the entire profile from the magnetic axis to the bottom of the pedestal. In the simulations, carried out using the automated system for transport analysis (ASTRA) integrated modeling code, different combinations of electron thermal transport models are considered. The combinations include models for electron temperature gradient (ETG) anomalous transport and trapped electron mode (TEM) anomalous transport, as well as a model for paleoclassical transport [J. D. Callen, Nucl. Fusion 45, 1120 (2005)]. It is found that the electromagnetic limit of the Horton ETG model [W. Horton et al., Phys. Fluids 31, 2971 (1988)] provides an important contribution near the magnetic axis, which is a region where the ETG mode in the GLF23 model [R. E. Waltz et al., Phys. Plasmas 4, 2482 (1997)] is below threshold. In simulations of DIII-D discharges, the observed shape of the H-mode edge pedestal is produced when transport associated with the TEM component of the GLF23 model is suppressed and transport given by the paleoclassical model is included. In a study involving 15 DIII-D H-mode discharges, it is found that with a particular combination of electron thermal transport models, the average rms deviation of the predicted electron temperature profile from the experimental profile is reduced to 9% and the offset to -4%.

Some factors affecting radiative heat transport in PWR cores

International Nuclear Information System (INIS)

Hall, A.N.

1989-04-01

This report discusses radiative heat transport in Pressurized Water Reactor cores, using simple models to illustrate basic features of the transport process. Heat transport by conduction and convection is ignored in order to focus attention on the restrictions on radiative heat transport imposed by the geometry of the heat emitting and absorbing structures. The importance of the spacing of the emitting and absorbing structures is emphasised. Steady state temperature distributions are found for models of cores which are uniformly heated by fission product decay. In all of the models, a steady state temperature distribution can only be obtained if the central core temperature is in excess of the melting point of UO 2 . It has recently been reported that the MIMAS computer code, which takes into account radiative heat transport, has been used to model the heat-up of the Three Mile Island-2 reactor core, and the computations indicate that the core could not have reached the melting point of UO 2 at any time or any place. We discuss this result in the light of the calculations presented in this paper. It appears that the predicted stabilisation of the core temperatures at ∼ 2200 0 C may be a consequence of the artificially large spacing between the radial rings employed in the MIMAS code, rather than a result of physical significance. (author)

Numerical simulation of seasonal heat storage in a contaminated shallow aquifer - Temperature influence on flow, transport and reaction processes

Science.gov (United States)

Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

2015-04-01

The energy market in Germany currently faces a rapid transition from nuclear power and fossil fuels towards an increased production of energy from renewable resources like wind or solar power. In this context, seasonal heat storage in the shallow subsurface is becoming more and more important, particularly in urban regions with high population densities and thus high energy and heat demand. Besides the effects of increased or decreased groundwater and sediment temperatures on local and large-scale groundwater flow, transport, geochemistry and microbiology, an influence on subsurface contaminations, which may be present in the urban surbsurface, can be expected. Currently, concerns about negative impacts of temperature changes on groundwater quality are the main barrier for the approval of heat storage at or close to contaminated sites. The possible impacts of heat storage on subsurface contamination, however, have not been investigated in detail yet. Therefore, this work investigates the effects of a shallow seasonal heat storage on subsurface groundwater flow, transport and reaction processes in the presence of an organic contamination using numerical scenario simulations. A shallow groundwater aquifer is assumed, which consists of Pleistoscene sandy sediments typical for Northern Germany. The seasonal heat storage in these scenarios is performed through arrays of borehole heat exchangers (BHE), where different setups with 6 and 72 BHE, and temperatures during storage between 2°C and 70°C are analyzed. The developing heat plume in the aquifer interacts with a residual phase of a trichloroethene (TCE) contamination. The plume of dissolved TCE emitted from this source zone is degraded by reductive dechlorination through microbes present in the aquifer, which degrade TCE under anaerobic redox conditions to the degradation products dichloroethene, vinyl chloride and ethene. The temperature dependence of the microbial degradation activity of each degradation step is

Internal transport barrier simulation and analysis in LHD

International Nuclear Information System (INIS)

GarcIa, J; Yamazaki, K; Dies, J; Izquierdo, J

2006-01-01

In order to study the electron heat transport channel and to clarify the electron thermal diffusivity dependence with some plasma parameters in large helical device (LHD) shots with electron internal transport barrier (eITB), some transport models have been added to the TOTAL code. These models can be divided into two categories: GyroBohm-like drift wave model and other drift wave models with shorter wavelength. A new model consisting of a mix of both models has also been derived for this study as a good candidate for explaining the eITB. The effect of anomalous transport reduction by the electric field shear has been introduced by means of the factor (1 + (τf ExB ) γ ) -1 . This factor has been previously checked as a good candidate to suppress anomalous transport in tokamak plasmas. Results show that a combination of the GyroBohm-like model and the drift wave model with shorter wavelength together with the electric field shear can explain the transition between non-eITB and eITB shots. The central temperature dependence with density is also well simulated. In the case of GyroBohm models, they also fit temperature profiles, although central temperature dependence with density is higher

Transition phenomena and thermal transport property in LHD plasmas with an electron internal transport barrier

International Nuclear Information System (INIS)

Shimozuma, T.; Kubo, S.; Idei, H.

2005-01-01

Two kinds of improved core confinement were observed during centrally focused Electron Cyclotron Heating (ECH) into plasmas sustained by Counter (CNTR) and Co Neutral Beam Injections (NBI) in the Large Helical Device (LHD). One shows transition phenomena to the high-electron-temperature state and has a clear electron Internal Transport Barrier (eITB) in CNTR NBI plasma. Another has no clear transition and no ECH power threshold, but shows a broad high temperature profiles with moderate temperature gradient, which indicates the improved core confinement with additional ECH in Co NBI plasma. The electron heat transport characteristics of these plasmas were directly investigated by using the heat pulse propagation excited by Modulated ECH (MECH). The difference of the features could be caused by the existence of the m/n=2/1 rational surface or island determined by the direction of NBI beam-driven current. (author)

Ultrafast Thermal Transport at Interfaces

Energy Technology Data Exchange (ETDEWEB)

Cahill, David [Univ. of Illinois, Champaign, IL (United States); Murphy, Catherine [Univ. of Illinois, Champaign, IL (United States); Martin, Lane [Univ. of Illinois, Champaign, IL (United States)

2014-10-21

Our research program on Ultrafast Thermal Transport at Interfaces advanced understanding of the mesoscale science of heat conduction. At the length and time scales of atoms and atomic motions, energy is transported by interactions between single-particle and collective excitations. At macroscopic scales, entropy, temperature, and heat are the governing concepts. Key gaps in fundamental knowledge appear at the transitions between these two regimes. The transport of thermal energy at interfaces plays a pivotal role in these scientific issues. Measurements of heat transport with ultrafast time resolution are needed because picoseconds are the fundamental scales where the lack of equilibrium between various thermal excitations becomes a important factor in the transport physics. A critical aspect of our work has been the development of experimental methods and model systems that enabled more precise and sensitive investigations of nanoscale thermal transport.

Nuclear reactor

International Nuclear Information System (INIS)

Tilliette, Z.

1975-01-01

A description is given of a nuclear reactor and especially a high-temperature reactor in which provision is made within a pressure vessel for a main cavity containing the reactor core and a series of vertical cylindrical pods arranged in spaced relation around the main cavity and each adapted to communicate with the cavity through two collector ducts or headers for the primary fluid which flows downwards through the reactor core. Each pod contains two superposed steam-generator and circulator sets disposed in substantially symmetrical relation on each side of the hot primary-fluid header which conveys the primary fluid from the reactor cavity to the pod, the circulators of both sets being mounted respectively at the bottom and top ends of the pod

Transport Coefficients of Fluids

CERN Document Server

Eu, Byung Chan

2006-01-01

Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.

Influence of structural properties on ballistic transport in nanoscale epitaxial graphene cross junctions

International Nuclear Information System (INIS)

Bock, Claudia; Weingart, Sonja; Karaissaridis, Epaminondas; Kunze, Ulrich; Speck, Florian; Seyller, Thomas

2012-01-01

In this paper we investigate the influence of material and device properties on the ballistic transport in epitaxial monolayer graphene and epitaxial quasi-free-standing monolayer graphene. Our studies comprise (a) magneto-transport in two-dimensional (2D) Hall bars, (b) temperature- and magnetic-field-dependent bend resistance of unaligned and step-edge-aligned orthogonal cross junctions, and (c) the influence of the lead width of the cross junctions on ballistic transport. We found that ballistic transport is highly sensitive to scattering at the step edges of the silicon carbide substrate. A suppression of the ballistic transport is observed if the lead width of the cross junction is reduced from 50 nm to 30 nm. In a 50 nm wide device prepared on quasi-free-standing graphene we observe a gradual transition from the ballistic into the diffusive transport regime if the temperature is increased from 4.2 to about 50 K, although 2D Hall bars show a temperature-independent mobility. Thus, in 1D devices additional temperature-dependent scattering mechanisms play a pivotal role. (paper)

Possible role of oceanic heat transport in early Eocene climate

Science.gov (United States)

Sloan, L. C.; Walker, J. C.; Moore, T. C. Jr

1995-01-01

Increased oceanic heat transport has often been cited as a means of maintaining warm high-latitude surface temperatures in many intervals of the geologic past, including the early Eocene. Although the excess amount of oceanic heat transport required by warm high latitude sea surface temperatures can be calculated empirically, determining how additional oceanic heat transport would take place has yet to be accomplished. That the mechanisms of enhanced poleward oceanic heat transport remain undefined in paleoclimate reconstructions is an important point that is often overlooked. Using early Eocene climate as an example, we consider various ways to produce enhanced poleward heat transport and latitudinal energy redistribution of the sign and magnitude required by interpreted early Eocene conditions. Our interpolation of early Eocene paleotemperature data indicate that an approximately 30% increase in poleward heat transport would be required to maintain Eocene high-latitude temperatures. This increased heat transport appears difficult to accomplish by any means of ocean circulation if we use present ocean circulation characteristics to evaluate early Eocene rates. Either oceanic processes were very different from those of the present to produce the early Eocene climate conditions or oceanic heat transport was not the primary cause of that climate. We believe that atmospheric processes, with contributions from other factors, such as clouds, were the most likely primary cause of early Eocene climate.

Electronic transport in VO{sub 2}—Experimentally calibrated Boltzmann transport modeling

Energy Technology Data Exchange (ETDEWEB)

Kinaci, Alper; Rosenmann, Daniel; Chan, Maria K. Y., E-mail: debasish.banerjee@toyota.com, E-mail: mchan@anl.gov [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kado, Motohisa [Higashifuji Technical Center, Toyota Motor Corporation, Susono, Shizuoka 410-1193 (Japan); Ling, Chen; Zhu, Gaohua; Banerjee, Debasish, E-mail: debasish.banerjee@toyota.com, E-mail: mchan@anl.gov [Materials Research Department, Toyota Motor Engineering and Manufacturing North America, Inc., Ann Arbor, Michigan 48105 (United States)

2015-12-28

Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO{sub 2} has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO{sub 2} in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO{sub 2} films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties.

Hot and steamy (but untrue) stories of the boiler emergency cooling system (BECS)

International Nuclear Information System (INIS)

Lorencez, C.; Bramble, A.

2004-01-01

The PNGS 'B' Boiler Emergency Cooling System (BECS) has been designed to provide interim makeup inventory to the boilers following a Loss of Feedwater, Steam Balance Header or Main Steam Line break event. Its objective is to operate as an interim heat sink to remove the excess energy in the Heat Transport System until a long term heat sink can be placed in service. The effectiveness of BECS has been assessed for a range of BECS tank water levels and pressure at the ambient Boiler Room (BR) temperature. Currently, BECS operates at a pressure of 160 kPa(g) and a water level of 2.2 m, and it is assumed that the water temperature is similar to that of the BR because there is no temperature instrumentation in tanks. However, it has been suggested that the coolant temperature in the BECS tanks may be much higher than the BR temperature in several PNGS 'B' units; this is attributed to in-leakage of high pressure and temperature water (at 4.7 Mpa(g) and 250 o C) from the Reheater Drains system into the BECS tanks, as observed by an increasing water tank levels in several units. Thus, to predict and assess the effect of the current in-leakage on the BECS water temperature, a numerical model of the BECS tanks was developed. (author)

Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

International Nuclear Information System (INIS)

Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

1988-01-01

Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

Simulated impurity transport in LHD from MIST

Energy Technology Data Exchange (ETDEWEB)

Rice, J.E. [National Inst. for Fusion Science, Toki, Gifu (Japan)

1998-05-01

The impurity transport code MIST and atomic physics package LINES are used to calculate the time evolution of charge state density profiles, individual line emissivity profiles and total radiated power profiles for impurities in LHD plasmas. Three model LHD plasmas are considered; a high density, low temperature case, a low density, high temperature case and the initial LHD start-up plasma (500 kW ECH), using impurity transport coefficient profiles from Heliotron E. The elements oxygen, neon, scandium, iron, nickel and molybdenum are considered, both injected and in steady state. (author)

Integrated modeling of temperature profiles in L-mode tokamak discharges

Energy Technology Data Exchange (ETDEWEB)

Rafiq, T.; Kritz, A. H.; Tangri, V. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado 80303 (United States); Voitsekhovitch, I. [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Budny, R. V. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-12-15

Simulations of doublet III-D, the joint European tokamak, and the tokamak fusion test reactor L-mode tokamak plasmas are carried out using the PTRANSP predictive integrated modeling code. The simulation and experimental temperature profiles are compared. The time evolved temperature profiles are computed utilizing the Multi-Mode anomalous transport model version 7.1 (MMM7.1) which includes transport associated with drift-resistive-inertial ballooning modes (the DRIBM model [T. Rafiq et al., Phys. Plasmas 17, 082511 (2010)]). The tokamak discharges considered involved a broad range of conditions including scans over gyroradius, ITER like current ramp-up, with and without neon impurity injection, collisionality, and low and high plasma current. The comparison of simulation and experimental temperature profiles for the discharges considered is shown for the radial range from the magnetic axis to the last closed flux surface. The regions where various modes in the Multi-Mode model contribute to transport are illustrated. In the simulations carried out using the MMM7.1 model it is found that: The drift-resistive-inertial ballooning modes contribute to the anomalous transport primarily near the edge of the plasma; transport associated with the ion temperature gradient and trapped electron modes contribute in the core region but decrease in the region of the plasma boundary; and neoclassical ion thermal transport contributes mainly near the center of the discharge.

Temperature variance study in Monte-Carlo photon transport theory

International Nuclear Information System (INIS)

Giorla, J.

1985-10-01

We study different Monte-Carlo methods for solving radiative transfer problems, and particularly Fleck's Monte-Carlo method. We first give the different time-discretization schemes and the corresponding stability criteria. Then we write the temperature variance as a function of the variances of temperature and absorbed energy at the previous time step. Finally we obtain some stability criteria for the Monte-Carlo method in the stationary case [fr

Transport modelling including radial electric field and plasma rotation

International Nuclear Information System (INIS)

Fukuyama, A.; Fuji, Y.; Itoh, S.-I.

1994-01-01

Using a simple turbulent transport model with a constant diffusion coefficient and a fixed temperature profile, the density profile in a steady state and the transient behaviour during the co and counter neutral beam injection are studied. More consistent analysis has been initiated with a turbulent transport model based on the current diffusive high-n ballooning mode. The enhancement of the radial electric field due to ion orbit losses and the reduction of the transport due to the poloidal rotation shear are demonstrated. The preliminary calculation indicates a sensitive temperature dependence of the density profile. (author)

An Overview of Liquid Fluoride Salt Heat Transport Systems

Energy Technology Data Exchange (ETDEWEB)

Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL

2010-09-01

Heat transport is central to all thermal-based forms of electricity generation. The ever increasing demand for higher thermal efficiency necessitates power generation cycles transitioning to progressively higher temperatures. Similarly, the desire to provide direct thermal coupling between heat sources and higher temperature chemical processes provides the underlying incentive to move toward higher temperature heat transfer loops. As the system temperature rises, the available materials and technology choices become progressively more limited. Superficially, fluoride salts at {approx}700 C resemble water at room temperature being optically transparent and having similar heat capacity, roughly three times the viscosity, and about twice the density. Fluoride salts are a leading candidate heat-transport material at high temperatures. Fluoride salts have been extensively used in specialized industrial processes for decades, yet they have not entered widespread deployment for general heat transport purposes. This report does not provide an exhaustive screening of potential heat transfer media and other high temperature liquids such as alkali metal carbonate eutectics or chloride salts may have economic or technological advantages. A particular advantage of fluoride salts is that the technology for their use is relatively mature as they were extensively studied during the 1940s-1970s as part of the U.S. Atomic Energy Commission's program to develop molten salt reactors (MSRs). However, the instrumentation, components, and practices for use of fluoride salts are not yet developed sufficiently for commercial implementation. This report provides an overview of the current understanding of the technologies involved in liquid salt heat transport (LSHT) along with providing references to the more detailed primary information resources. Much of the information presented here derives from the earlier MSR program. However, technology has evolved over the intervening years

Intrinsic and extrinsic electrical and thermal transport of bulk black phosphorus

Science.gov (United States)

Hu, Sile; Xiang, Junsen; Lv, Meng; Zhang, Jiahao; Zhao, Hengcan; Li, Chunhong; Chen, Genfu; Wang, Wenhong; Sun, Peijie

2018-01-01

We report a comprehensive investigation of the electrical, thermal, and thermoelectric transport properties of bulk single-crystalline black phosphorus in wide temperature (2-300 K) and field (0-9 T) ranges. Electrical transport below T ≈ 250 K is found to be dominated by extrinsic hole-type charge carriers with large mobility exceeding 104 cm2/V s at low temperatures. While thermal transport measurements reveal an enhanced in-plane thermal conductivity maximum κ = 180 W/m K at T ≈ 25 K, it appears still to be largely constrained by extrinsic phonon scattering processes, e.g., the electron-phonon process, in addition to intrinsic umklapp scattering. The thermoelectric power and Nernst effect seem to be strongly influenced by ambipolar transport of charge carriers with opposite signs in at least the high-temperature region above 200 K, which diminishes the thermoelectric power factor of this material. Our results provide a timely update to the transport properties of bulk black phosphorus for future fundamental and applied research.

Research on crude oil storage and transportation based on optimization algorithm

Science.gov (United States)

Yuan, Xuhua

2018-04-01

At present, the optimization theory and method have been widely used in the optimization scheduling and optimal operation scheme of complex production systems. Based on C++Builder 6 program development platform, the theoretical research results are implemented by computer. The simulation and intelligent decision system of crude oil storage and transportation inventory scheduling are designed. The system includes modules of project management, data management, graphics processing, simulation of oil depot operation scheme. It can realize the optimization of the scheduling scheme of crude oil storage and transportation system. A multi-point temperature measuring system for monitoring the temperature field of floating roof oil storage tank is developed. The results show that by optimizing operating parameters such as tank operating mode and temperature, the total transportation scheduling costs of the storage and transportation system can be reduced by 9.1%. Therefore, this method can realize safe and stable operation of crude oil storage and transportation system.

Effect of Structure on Transport Properties (Viscosity, Ionic Conductivity, and Self-Diffusion Coefficient) of Aprotic Heterocyclic Anion (AHA) Room-Temperature Ionic Liquids. 1. Variation of Anionic Species.

Science.gov (United States)

Sun, Liyuan; Morales-Collazo, Oscar; Xia, Han; Brennecke, Joan F

2015-12-03

A series of room temperature ionic liquids (RTILs) based on 1-ethyl-3-methylimidazolium ([emim](+)) with different aprotic heterocyclic anions (AHAs) were synthesized and characterized as potential electrolyte candidates for lithium ion batteries. The density and transport properties of these ILs were measured over the temperature range between 283.15 and 343.15 K at ambient pressure. The temperature dependence of the transport properties (viscosity, ionic conductivity, self-diffusion coefficient, and molar conductivity) is fit well by the Vogel-Fulcher-Tamman (VFT) equation. The best-fit VFT parameters, as well as linear fits to the density, are reported. The ionicity of these ILs was quantified by the ratio of the molar conductivity obtained from the ionic conductivity and molar concentration to that calculated from the self-diffusion coefficients using the Nernst-Einstein equation. The results of this study, which is based on ILs composed of both a planar cation and planar anions, show that many of the [emim][AHA] ILs exhibit very good conductivity for their viscosities and provide insight into the design of ILs with enhanced dynamics that may be suitable for electrolyte applications.

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Murakami, M.; Adler, H.; Chang, Z.; Duong, H.; Grisham, L.R.; Fredrickson, E.D.; Grek, B.; Hawryluk, R.J.; Hill, K.W.; Hosea, J.; Jassby, D.L.; Johnson, D.W.; Johnson, L.C.; Loughlin, M.J.; Mansfield, D.K.; McGuire, K.M.; Meade, D.M.; Mikkelsen, D.M.; Murphy, J.; Park, H.K.; Ramsey, A.T.; Schivell, J.; Skinner, C.H.; Strachan, J.D.; Synakowski, E.J.; Taylor, G.; Thompson, M.E.; Wieland, R.; Zarnstorff, M.C.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ left angle A right angle 0.7-0.8 and τ pe (a) ∝ left angle A right angle 0.8 . (orig.)

Orbital transport

International Nuclear Information System (INIS)

Oertel, H. Jr.; Koerner, H.

1993-01-01

The Third Aerospace Symposium in Braunschweig presented, for the first time, the possibility of bringing together the classical disciplines of aerospace engineering and the natural science disciplines of meteorology and air chemistry in a european setting. In this way, aspects of environmental impact on the atmosphere could be examined quantitatively. An essential finding of the european conference, is the unrestricted agreement of the experts that the given launch frequencies of the present orbital transport result in a negligible amount of pollutants being released in the atmosphere. The symposium does, however, call attention to the increasing need to consider the effect of orbital and atmospheric environmental impact of a future increase in launch frequencies of orbital transport in connection with future space stations. The Third Aerospace Symposium, 'Orbital Transport, Technical, Meteorological and Chemical Aspects', constituted a first forum of discussion for engineers and scientists. Questions of new orbital transport technologies and their environmental impact were to be discussed towards a first consensus. Through the 34 reports and articles, the general problems of space transportation and environmental protection were addressed, as well as particular aspects of high temperatures during reentry in the atmosphere of the earth, precision navigation of flight vehicles or flow behavior and air chemistry in the stratosphere. (orig./CT). 342 figs

Compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2 as substitutes for SF6 to reduce global warming potential

Directory of Open Access Journals (Sweden)

Linlin Zhong

2017-07-01

Full Text Available C5F10O has recently been found to be a very promising alternative to SF6. This paper is devoted to the investigation of compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2. Firstly, the partition functions and enthalpies of formation for a few molecules (CxFy and CxFyO which are likely to exist in the mixtures, are calculated based on the G4(MP2 theory. The isomers of the above molecules are selected according to their Gibbs energy. The compositions of C5F10O-CO2-O2 mixtures are then determined using the minimization of the Gibbs free energy. Next, the thermodynamic properties (mass density, specific enthalpy, and specific heat are derived from the previously calculated compositions. Lastly, the transport coefficients (electrical conductivity, viscosity, and thermal conductivity are calculated based on Chapman-Enskog method. It is found that, as an arc quenching gas, C5F10O could not recombine into itself with the temperature decreasing down to room temperature after the arc extinction. Besides, the key species at room temperature are always CF4, CO2, and C4F6 if graphite is not considered. When taken into account, graphite will replace C4F6 as one of the dominate particles. The mixing of CO2 with C5F10O plasma significantly affects the thermodynamic properties (e.g. vanishing and/or shifting of the peaks in specific heat and transport coefficients (e.g. reducing viscosity and changing the number of peaks in thermal conductivity, while the addition of O2 with C5F10O-CO2 mixtures has no remarkable influence on both thermodynamic and transport properties.

Compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2 as substitutes for SF6 to reduce global warming potential

Science.gov (United States)

Zhong, Linlin; Rong, Mingzhe; Wang, Xiaohua; Wu, Junhui; Han, Guiquan; Han, Guohui; Lu, Yanhui; Yang, Aijun; Wu, Yi

2017-07-01

C5F10O has recently been found to be a very promising alternative to SF6. This paper is devoted to the investigation of compositions, thermodynamic properties, and transport coefficients of high-temperature C5F10O mixed with CO2 and O2. Firstly, the partition functions and enthalpies of formation for a few molecules (CxFy and CxFyO) which are likely to exist in the mixtures, are calculated based on the G4(MP2) theory. The isomers of the above molecules are selected according to their Gibbs energy. The compositions of C5F10O-CO2-O2 mixtures are then determined using the minimization of the Gibbs free energy. Next, the thermodynamic properties (mass density, specific enthalpy, and specific heat) are derived from the previously calculated compositions. Lastly, the transport coefficients (electrical conductivity, viscosity, and thermal conductivity) are calculated based on Chapman-Enskog method. It is found that, as an arc quenching gas, C5F10O could not recombine into itself with the temperature decreasing down to room temperature after the arc extinction. Besides, the key species at room temperature are always CF4, CO2, and C4F6 if graphite is not considered. When taken into account, graphite will replace C4F6 as one of the dominate particles. The mixing of CO2 with C5F10O plasma significantly affects the thermodynamic properties (e.g. vanishing and/or shifting of the peaks in specific heat) and transport coefficients (e.g. reducing viscosity and changing the number of peaks in thermal conductivity), while the addition of O2 with C5F10O-CO2 mixtures has no remarkable influence on both thermodynamic and transport properties.

Mechanism transition of cell-impedance-controlled lithium transport through Li1-δMn2O4 composite electrode caused by surface-modification and temperature variation

International Nuclear Information System (INIS)

Jung, Kyu-Nam; Pyun, Su-Il

2007-01-01

The mechanism transition of lithium transport through a Li 1-δ Mn 2 O 4 composite electrode caused by the surface-modification and temperature variation was investigated using the galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS) and the potentiostatic current transient technique. From the analyses of the ac-impedance spectra, experimentally measured from unmodified Li 1-δ Mn 2 O 4 and surface-modified Li 1-δ Mn 2 O 4 with MgO composite electrodes, the internal cell resistance of the MgO-modified Li 1-δ Mn 2 O 4 electrode was determined to be much smaller in value than that of the unmodified electrode over the whole potential range. Moreover, from the analysis of the anodic current transients measured on the MgO-modified Li 1-δ Mn 2 O 4 electrode, it was found that the cell-impedance-controlled constraint at the electrode surface is changed to a diffusion-controlled constraint, which is characterised by a large potential step and simultaneously by a small amount of lithium transferred during lithium transport. This strongly suggests that the internal cell resistance plays a significant role in determining the cell-impedance-controlled lithium transport through the MgO-modified Li 1-δ Mn 2 O 4 electrode. Furthermore, from the temperature dependence of the internal cell resistance and diffusion resistance in the unmodified Li 1-δ Mn 2 O 4 composite electrode measured by GITT and EIS, it was concluded that which mechanism of lithium transport will be operative strongly depends on the diffusion resistance as well as on the internal cell resistance

Total Dose Effects on Bipolar Integrated Circuits at Low Temperature

Science.gov (United States)

Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

2012-01-01

Total dose damage in bipolar integrated circuits is investigated at low temperature, along with the temperature dependence of the electrical parameters of internal transistors. Bandgap narrowing causes the gain of npn transistors to decrease far more at low temperature compared to pnp transistors, due to the large difference in emitter doping concentration. When irradiations are done at temperatures of -140 deg C, no damage occurs until devices are warmed to temperatures above -50 deg C. After warm-up, subsequent cooling shows that damage is then present at low temperature. This can be explained by the very strong temperature dependence of dispersive transport in the continuous-time-random-walk model for hole transport. For linear integrated circuits, low temperature operation is affected by the strong temperature dependence of npn transistors along with the higher sensitivity of lateral and substrate pnp transistors to radiation damage.

Thermal analysis on NAC-STC spent fuel transport cask under different transport conditions

Energy Technology Data Exchange (ETDEWEB)

Xu, Yumei [Institute of Process Equipment, Zhejiang University, Hangzhou (China); Yang, Jian, E-mail: zdhjkz@zju.edu.cn [Institute of Process Equipment, Zhejiang University, Hangzhou (China); Xu, Chao; Wang, Weiping [Institute of Process Equipment, Zhejiang University, Hangzhou (China); Ma, Zhijun [Department of Material Engineering, South China University of Technology, Guangzhou (China)

2013-12-15

Highlights: • Spent fuel cask was investigated as a whole instead of fuel assembly alone. • The cask was successfully modeled and meshed after several simplifications. • Equivalence method was used to calculate the properties of parts. • Both the integral thermal field and peak values are captured to verify safety. • The temperature variations of key parts were also plotted. - Abstract: Transport casks used for conveying spent nuclear fuel are inseparably related to the safety of the whole reprocessing system for spent nuclear fuel. Thus they must be designed according to rigorous safety standards including thermal analysis. In this paper, for NAC-STC cask, a finite element model is established based on some proper simplifications on configurations and the heat transfer mechanisms. Considering the complex components and gaps, the equivalence method is presented to define their material properties. Then an equivalent convection coefficient is introduced to define boundary conditions. Finally, the temperature field is captured and analyzed under both normal and accident transport conditions by using ANSYS software. The validity of numerical calculation is given by comparing its results with theoretical calculation. Obtaining the integral distribution laws of temperature and peak temperature values of all vital components, the security of the cask can be evaluated and verified.

Elucidation of the origins of transport behaviour and quantum oscillations in high temperature superconducting cuprates

International Nuclear Information System (INIS)

Wilson, John A

2009-01-01

A detailed exposition is given of recent transport and 'quantum oscillation' results from high temperature superconducting (HTSC) systems covering the full carrier range from overdoped to underdoped material. This now very extensive and high quality data set is here interpreted within the framework developed by the author of local pairs and boson-fermion resonance, arising in the context of negative- U behaviour within an inhomogeneous electronic environment. The strong inhomogeneity comes with the mixed-valence condition of these materials, which when underdoped lie in close proximity to the Mott-Anderson transition. The observed intense scattering is presented as resulting from pair formation and from electron-boson collisions in the resonant crossover circumstance. The high level of scattering carries the systems to incoherence in the pseudogapped state, p c (= 0.183). In a high magnetic field the striped partition of the inhomogeneous charge distribution becomes much strengthened and regularized. Magnetization and resistance oscillations, of period dictated by the favoured positioning of the fluxon array within the real space environment of the diagonal 2D charge striping array, are demonstrated to be responsible for the recently reported behaviour hitherto widely attributed to the quantum oscillation response of a much more standard Fermi liquid condition. A detailed analysis embracing all the experimental data serves to reveal that in the given conditions of very high field, low temperature, 2D-striped, underdoped, d-wave superconducting, HTSC material the flux quantum becomes doubled to h/e.

Behavior of electron and ion transport in discharges with an internal transport barrier in the DIII-D tokamak

International Nuclear Information System (INIS)

Greenfield, C.M.; Staebler, G.M.; Rettig, C.L.

1999-01-01

We report results of experiments to further determine the underlying physics behind the formation and development of internal transport barriers (ITB) in the DIII-D tokamak. The initial ITB formation occurs when the neutral beam heating power exceeds a threshold value during the early stages of the current ramp in low-density discharges. This region of reduced transport, made accessible by suppression of long-wavelength turbulence by sheared flows, is most evident in the ion temperature and impurity rotation profiles. In some cases, reduced transport is also observed in the electron temperature and density profiles. If the power is near the threshold, the barrier remains stationary and encloses only a small fraction of the plasma volume. If, however, the power is increased, the transport barrier expands to encompass a larger fraction of the plasma volume. The dynamic behavior of the transport barrier during the growth phase exhibits rapid transport events that are associated with both broadening of the profiles and reductions in turbulence and associated transport. In some, but not all, cases, these events are correlated with the safety factor q passing through integer values. The final state following this evolution is a plasma exhibiting ion thermal transport at or below neoclassical levels. Typically, the electron thermal transport remains anomalously high. Recent experimental results are reported in which rf electron heating was applied to plasmas with an ion ITB, thereby increasing both the electron and ion transport. Although the results are partially in agreement with the usual E-vector x B-vector shear suppression hypothesis, the results still leave questions that must be addressed in future experiments. (author)

Behavior of electron and ion transport in discharges with an internal transport barrier in the DIII-D tokamak

International Nuclear Information System (INIS)

Greenfield, C.M.; Staebler, G.M.; Rettig, C.L.

1998-12-01

The authors report results of experiments to further determine the underlying physics behind the formation and development of internal transport barriers (ITB) in the DIII-D tokamak. The initial ITB formation occurs when the neutral beam heating power exceeds a threshold value during the early stages of the current ramp in low-density discharges. This region of reduced transport, made accessible by suppression of long-wavelength turbulence by sheared flows, is most evident in the ion temperature and impurity rotation profiles. In some cases, reduced transport is also observed in the electron temperature and density profiles. If the power is near the threshold, the barrier remains stationary and enclosed only a small fraction of the plasma volume. If, however, the power is increased, the transport barrier expands to encompass a larger fraction of the plasma volume. The dynamic behavior of the transport barrier during the growth phase exhibits rapid transport events that are associated with both broadening of the profiles and reductions in turbulence and associated transport. In some, but not all, cases, these events are correlated with the safety factor q passing through integer values. The final state following this evolution is a plasma exhibiting ion thermal transport at or below neoclassical levels. Typically, the electron thermal transport remains anomalously high. Recent experimental results are reported in which rf electron heating was applied to plasmas with an ion ITB, thereby increasing both the electron and ion transport. Although the results are partially in agreement with the usual rvec E x rvec B shear suppression hypothesis, the results still leave questions that must be addressed in future experiments

Low-Temperature Band Transport and Impact of Contact Resistance in Organic Field-Effect Transistors Based on Single-Crystal Films of Ph-BTBT-C10

Science.gov (United States)

Cho, Joung-min; Mori, Takehiko

2016-06-01

Transistors based on single-crystal films of 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) fabricated using the blade-coating method are investigated by the four-probe method down to low temperatures. The four-probe mobility is as large as 18 cm2/V s at room temperature, and increases to 45 cm2/V s at 80 K. At 60 K the two-probe mobility drops abruptly by about 50%, but the mobility drop is mostly attributed to the increase of the source resistance. The carrier transport in the present single-crystal film is regarded as essentially bandlike down to 30 K.

Charge transport in transparent single-wall carbon nanotube networks

International Nuclear Information System (INIS)

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

2007-01-01

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

Suprathermal ion transport in turbulent magnetized plasmas

International Nuclear Information System (INIS)

Bovet, A. D.

2015-01-01

Suprathermal ions, which have an energy greater than the quasi-Maxwellian background plasma temperature, are present in many laboratory and astrophysical plasmas. In fusion devices, they are generated by the fusion reactions and auxiliary heating. Controlling their transport is essential for the success of future fusion devices that could provide a clean, safe and abundant source of electric power to our society. In space, suprathermal ions include energetic solar particles and cosmic rays. The understanding of the acceleration and transport mechanisms of these particles is still incomplete. Basic plasma devices allow detailed measurements that are not accessible in astrophysical and fusion plasmas, due to the difficulty to access the former and the high temperatures of the latter. The basic toroidal device TORPEX offers an easy access for diagnostics, well characterized plasma scenarios and validated numerical simulations of its turbulence dynamics, making it the ideal platform for the investigation of suprathermal ion transport. This Thesis presents three-dimensional measurements of a suprathermal ion beam injected in turbulent TORPEX plasmas. The combination of uniquely resolved measurements and first principle numerical simulations reveals the general non-diffusive nature of the suprathermal ion transport. A precise characterization of their transport regime shows that, depending on their energies, suprathermal ions can experience either a super diffusive transport or a subdiffusive transport in the same background turbulence. The transport character is determined by the interaction of the suprathermal ion orbits with the turbulent plasma structures, which in turn depends on the ratio between the ion energy and the background plasma temperature. Time-resolved measurements reveal a clear difference in the intermittency of suprathermal ions time-traces depending on the transport regime they experience. Conditionally averaged measurements uncover the influence of

Diffusion and transport phenomena in a collisional magnetoplasma ...

Indian Academy of Sciences (India)

Boltzmann-transport equation is analytically solved for two-component magnetoplasma using Chapman-Enskog analysis to include collisional diffusion transport having anisotropies in both streaming velocity and temperature components. The modified collisional integrals are analytically solved with flux integrals and ...

CARRIER TRANSPORT IN MESOSCOPIC SILICON-COUPLED SUPERCONDUCTING JUNCTIONS

NARCIS (Netherlands)

VANHUFFELEN, WM; KLAPWIJK, TM; HESLINGA, DR; DEBOER, MJ; VANDERPOST, N

1993-01-01

An overview is presented of experimental results on supercurrent flow and transport at finite voltages in a well-characterized, sandwich-type superconductor-semiconductor-superconductor junction. Carrier transport through the structure is found to be dominated by the interfaces. At low temperatures,

Temperature in the Primary Heat Transport Pump Bearing of the Nuclear Power Plant 'Embalse Rio Tercero' in view of the Cutting of the Service Water

International Nuclear Information System (INIS)

Raffo, J.L

2001-01-01

This study contains the analysis of the Primary Heat Transport Pump Bearing of the Nuclear Power Plant 'Embalse Rio Tercero', Cordoba, Argentine, in view of the cutting of the Service Water refrigeration which cools the Gland Seal System.This takes two ways: One is the study of the temperature rise of the water that cools the carbon bearing and the time involved.This is supported upon manuals and drawings.The other, on the temperature distribution in different operating conditions.This has been done by the simulation of the normal and transient conditions in the software COSMOS/M

Low temperature magnetic structure of MnSe

Indian Academy of Sciences (India)

Abstract. In this paper we report low temperature neutron diffraction studies on MnSe in order to understand the anomalous behaviour of their magnetic and transport prop- erties. Our study indicates that at low temperatures MnSe has two coexisting crystal structures, high temperature NaCl and hexagonal NiAs. NiAs phase ...

Temperature, salinity, oxygen and fluorescence profiles collected by CTD from the Norseman II in Bering Strait from 2013-07-04 to 2013-07-10 (NCEI Accession 0136939)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archive is of data from 150 CTD casts taken during the 2013 Norseman II cruise to the Bering Strait. For positions, see file headers or the cruise report...

Study of the Cooldown and Warmup for the Eight Sectors of the Large Hadron Collider

Science.gov (United States)

Liu, L.; Riddone, G.; Tavian, L.

2004-06-01

The LHC cryogenic system is based on a five-point feed scheme with eight refrigerators serving the eight sectors of the LHC machine. The paper presents the simplified flow scheme of the eight sectors and the mathematical methods including the program flowchart and the boundary conditions to simulate the cooldown and warmup of these sectors. The methods take into account the effect of the pressure drop across the valves as well as the pressure evolution in the different headers of the cryogenic distribution line. The simulated pressure and temperature profiles of headers of the LHC sector during the cooldown and warmup are given and the temperature evolutions of entire processes of cooldown and warmup are presented. As a conclusion, the functions of the input temperature for the normal and fast cooldown and warmup, the cooldown and warmup time of each sector and the distributions of mass flow rates in each sector are summarized. The results indicate that it is possible to cool down any of the LHC sector within 12.7 days in normal operation and 6.8 days in case of fast operation.

Dynamic thermal baffle on lower head of FBR sodium-sodium intermediate heat exchanger

International Nuclear Information System (INIS)

Charbonnel, A.; Foussat, C.

1981-01-01

The cover head of the heat exchanger is bathed on the one side by the primary sodium of the 'cold' header of the vessel and on the other side by the secondary sodium which feeds the heat exchange tube bank through the lower tubesheet. In the case of transient or permanent operating conditions at partial ratings, there are large temperature differences between the inner sodium (inlet temperature conditions of secondary sodium) and the outer sodium (mean temperature conditions in the primary sodium outlet port), hence the necessity of designing a thermal baffle which protects the head and its connection to the tubesheet. A 'static' thermal baffle consisting of a thick steel plate enclosing static sodium around the head proves inadequate during transient operating conditions. This is why a 'dynamic' thermal baffle is used whose design is based on the fact that the primary sodium in the lower part of the outlet port is always at a temperature close to that of the secondary sodium in the inlet header and the head. The primary sodium is taken from the bottom of the outlet port by a ring deflector and circulates in an annulus created by a double housing and the head. It flows out through openings in the lower part of the housing. (orig./GL)

Electrical Transport and Magnetoresistance in Single-Wall Carbon Nanotubes Films

Directory of Open Access Journals (Sweden)

Vitaly KSENEVICH

2014-06-01

Full Text Available Electrical transport properties and magnetoresistance of single-wall carbon nanotubes (SWCNT films were investigated within temperature range (2 – 300 K and in magnetic fields up to 8 T. A crossover between metallic (dR/dT > 0 and non-metallic (dR/dT < 0 temperature dependence of the resistance as well as low-temperature saturation of the resistance in high bias regime indicated on the diminishing of role of the contact barriers between individual nanotubes essential for the charge transport in SWCNT arrays. The magnetoresistance (MR data demonstrated influence of weak localization and electron-electron interactions on charge transport properties in SWCNT films. The low-field negative MR with positive upturn was observed at low temperatures. At T > 10 K only negative MR was observed in the whole range of available magnetic fields. The negative MR can be approximated using 1D weak localization (WL model. The low temperature positive MR is induced by contribution from electron-electron interactions. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6311

Plasma thermal energy transport: theory and experiments

International Nuclear Information System (INIS)

Coppi, B.

Experiments on the transport across the magnetic field of electron thermal energy are reviewed (Alcator, Frascati Torus). In order to explain the experimental results, a transport model is described that reconfirmed the need to have an expression for the local diffusion coefficient with a negative exponent of the electron temperature

Electric field and transport in W7-AS

International Nuclear Information System (INIS)

Kick, M.; Maassberg, H.; Anton, M.; Baldzuhn, J.; Endler, M.; Goerner, C.; Hirsch, M.; Weller, A.; Zoletnik, S.

1999-01-01

At W7-AS, confinement properties are analysed and compared mainly with neoclassical predictions for quite different conditions. Low-density electron cyclotron resonance heating (ECRH) discharges allow access to the very-long-mean-free-path regime for electrons (T e up to 6 keV) whereas pure neutral beam injections (NBI) and combined NBI/ECRH discharges at high density (T i approx. T e ≥ 1 keV at n e approx. 10 20 m -3 ) lead to high performance (τ B up to 50 ms). Depending on the achieved temperatures, the experimental transport analysis in the plasma core is consistent with the neoclassical predictions. The experimentally observed 'electron root' feature with strong E r >0 is driven by the convective flux of ripple-trapped suprathermal electrons generated by the ECRH absorption. 'Optimum' confinement is obtained in discharges with narrow density, but broad temperature profiles with steep gradients in the region of low densities and strong E r <0 close to the plasma edge. The large radial electric fields, both positive and negative, strongly reduce neoclassical transport. The achieved temperatures, however, are limited by the strong temperature dependence of the neoclassical transport. (author)

High temperature vapors science and technology

CERN Document Server

Hastie, John

2012-01-01

High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

Temperature impact on cementitious materials carbonation - description of water transport influence

International Nuclear Information System (INIS)

Drouet, E.

2010-11-01

Carbonation is the major cause of degradation of reinforced concrete structures. It leads to rebar corrosion and cracking of the concrete cover. In the framework of radioactive waste management, cement-based materials used as building material for structures or containers would be simultaneously submitted to heating (due to the waste thermal output), subsequent drying and atmospheric carbon dioxide. Such environmental conditions are expected to modify the carbonation mechanisms (with respect to temperature). In order to describe their long-term evolution of material, a double approach was developed, combining the description of carbonation and drying for temperatures up to 80 C to complement available data at ambient temperature. The present work focuses on the durability study of four hardened cement pastes; two of them are derived from the reference formulations selected by Andra (CEM I and CEM V) and a low-pH mix. The first experimental campaign focuses on moisture transfer. The effect of temperature on drying is investigated through water vapour desorption experiments. The first desorption isotherms of four hardened cement pastes was characterized at 20, 50 and 80 C. The results show a significant influence of the temperature. For a given relative humidity (RH) the water content equilibrium is always reduced temperature is increased and the starting point of capillary condensation is shifted towards higher RHs. The experimental campaign is complemented through modelling activities. The impact of temperature on the first desorption isotherms is effectively described using the Clausius-Clapeyron equation (characterization of the isosteric heat of adsorption). The intrinsic permeability to water is evaluated through inverse analysis by reprocessing the experimental weight loss of initially saturated samples submitted to constant environmental conditions. The intrinsic permeability appears to increase with temperature in relation to the observed microstructure

Energy transport in cooling device by magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Hiroshi, E-mail: hyamaguc@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyo-tanabe, Kyoto 610-0321 (Japan); Iwamoto, Yuhiro [Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555 (Japan)

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

Energy transport in cooling device by magnetic fluid

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-01-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

Low-temperature localization in the transport properties of self-doped

Indian Academy of Sciences (India)

... such as electron–electron, Kondo, electron–phonon and electron–magnon are found to be strongly influenced by the applied magnetic field. The results suggest that interplay between electron–electron and Kondo-like scatterings lead to the localization in the temperature dependence of resistivity at low temperature.

Development of Nanoscale Graphitic Devices and The Transport Characterization

International Nuclear Information System (INIS)

Gunasekaran, Venugopal

2011-02-01

This dissertation describes the development of graphitic based nanoscale devices with its fabrication and transport characterization results. It covers graphite nano-scale stacked-junctions fabricated using focused ion beam (FIB) 3-D etching technique, a single layer graphite layer (graphene) preparation and its electrical transport characterization results and the synthesis and investigation of electrical transport behavior of graphene oxide based thin film devices. The first chapter describes the basic information about the carbon family in detail in which the electronic properties and structure of graphite, graphene and graphene oxide are discussed. In addition, the necessity of developing nanoscale graphitic devices is given. The second chapter explains the experimental techniques used in this research for fabricating nanoscale devices which includes focused ion beam 3-D fabrication procedures, mechanical exfoliation technique and photolithographic methods. In third chapter, we have reported the results on temperature dependence of graphite planar-type structures fabricated along ab-plane. In the fourth and fifth chapters, the fabrication and electrical transport characteristics of large in-plane area graphite planar-type structures (fabricated along ab-plane and c-axis) were discussed and their transport anisotropy properties were investigated briefly. In the sixth chapter, we focused the fabrication of the submicron sized graphite stacked junctions and their electrical transport characterization studies. In which, FIB was used to fabricated the submicron junctions with various in-plane area (with same stack height) are and their transport characteristics were compared. The seventh chapter reports investigation of electrical transport results of nanoscale graphite stacked-junctions in which the temperature dependent transport (R-T) studies, current-voltage measurements for the various in-plane areas and for various stack height samples were analyzed. The

Inverse method for stress monitoring in pressure components of steam generators

International Nuclear Information System (INIS)

Duda, P.

2003-01-01

The purpose of this work is to formulate a space marching method, which can be used to solve inverse multidimensional heat conduction problems. The method is designed to reconstruct the transient temperature distribution in a whole construction element based on measured temperatures taken at selected points inside or on the outer surface of the construction element. Next, the Finite Element Method is used to calculate thermal stresses and stresses caused by other loads such as, for instance, internal pressure. The developed method for solving temperature and total stress distribution will be tested using the measured temperatures generated from a direct solution. Transient temperature and total stress distribution obtained from method presented below will be compared with the values obtained from the direct solution. Finally, the presented method will be applied in order to monitor temperature and stress distribution in an outlet header using the real measured temperature values at seven points on the header's outer surface during the power boiler's shut down operation. The presented method allows to optimize the power block's start-up and shut-down operations, contributes to the reduction of heat loss during these operations and to the extension of power block's life. The fatigue and creep usage factor can be computed in an on-line mode. The presented method herein can be applied to monitoring systems that work in conventional as well as in nuclear power plants. (author)

Dynamic transport study of the plasmas with transport improvement in LHD and JT-60U

International Nuclear Information System (INIS)

Ida, K.; Inagaki, S.; Sakamoto, R.; Tanaka, K.; Fujita, T.; Funaba, H.; Kubo, S.; Yoshinuma, M.; Shimozuma, T.; Takeiri, Y.; Ikeda, K.; Michael, C.; Tokuzawa, T.; Sakamoto, Y.; Takenaga, H.; Isayama, A.; Matsunaga, G.; Ide, S.

2009-01-01

Transport analysis during the transient phase of heating (a dynamic transport study) applied to the plasma with internal transport barriers (ITBs) in the Large Helical Device (LHD) heliotron and the JT-60U tokamak is described. In the dynamic transport study the time of transition from the L-mode plasma to the ITB plasma is clearly determined by the onset of flattening of the temperature profile in the core region and a spontaneous phase transition from a zero curvature ITB (hyperbolic tangent shaped ITB) or a positive curvature ITB (concaved shaped ITB) to a negative curvature ITB (convex shaped ITB) and its back-transition are observed. The flattening of the core region of the ITB transition and the back-transition between a zero curvature ITB and a convex ITB suggest the strong interaction of turbulent transport in space.

ADVANCED CUTTINGS TRANSPORT STUDY

Energy Technology Data Exchange (ETDEWEB)

Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Lei Zhou

2000-01-30

This is the second quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between Oct 1, 2000 and December 31, 2000. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 2: Addition of a foam generation and breaker system), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (d) Research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (e) Research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Research on instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), and Foam properties while transporting cuttings. (Task 12), (h) Development of a Safety program for the ACTS Flow Loop. Progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members. The tasks Completed During This Quarter are Task 7 and Task 8.

Water transport in desert alluvial soil

International Nuclear Information System (INIS)

Kearl, P.M.

1982-04-01

Safe storage of radioactive waste buried in an arid alluvial soil requires extensive site characterization of the physical process influencing moisture movement which could act as a transport medium for the migration of radionuclides. The field portion of this study included an infiltration plot instrumented with thermocouple psychrometers and neturon moisture probe access holes. Baseline information shows a zone of higher moisture content at approximately 1.5 m (5 ft) in depth. A sprinkler system simulated a 500-year precipitation event. Results revealed water penetrated the soil to 0.9 m (2.9 ft). Due to the low moisture content, vapor transport was primarily responsible for water movement at this depth. Temperature gradients are substantially responsible for vapor transport by preferentially sorting water-vapor molecules from the surrounding air by using the soil as a molecular sieve. Adsorbed and capillary water vapor pressure increases in response to a temperature increase and releases additional water to the soil pore atmosphere to be diffused away

Transport of light, trace impurities in Alcator C-Mod

Science.gov (United States)

Rowan, W. L.; Bespamyatnov, I. O.; Liao, K. T.; Horton, W.; Fu, X. R.; Hughes, J. W.

2012-10-01

Light impurity profiles for boron were measured in ITB, H-mode, L-mode, and I-mode discharges in Alcator C-Mod. Within this wide range of modes, the profiles varied from peaked to hollow to flat. Specifically, hollow profiles are often observed in H-mode, while ITBs produce strong peaking, and L-mode produces moderate peaking. I-mode discharges are characterized by flat impurity profiles. For the study reported here, the profiles were measured with charge exchange recombination spectroscopy. The dependences of Rv/D were sought on dimensionless quantities including ion density scale length, effective charge, collisionality, and temperature scale length. We find that neoclassical transport consistently underestimates the measured transport. The excess measured transport is assumed to be turbulent. The strongest dependence of Rv/D is with temperature scale length. In addition, the measured transport was compared with the prediction of an analytical theory of drift wave turbulence that identifies transport implications for drift waves driven by ion and impurity density gradients.

A randomized clinical trial of therapeutic hypothermia mode during transport for neonatal encephalopathy.

Science.gov (United States)

Akula, Vishnu Priya; Joe, Priscilla; Thusu, Kajori; Davis, Alexis S; Tamaresis, John S; Kim, Sunhwa; Shimotake, Thomas K; Butler, Stephen; Honold, Jose; Kuzniewicz, Michael; DeSandre, Glenn; Bennett, Mihoko; Gould, Jeffrey; Wallenstein, Matthew B; Van Meurs, Krisa

2015-04-01

To determine if temperature regulation is improved during neonatal transport using a servo-regulated cooling device when compared with standard practice. We performed a multicenter, randomized, nonmasked clinical trial in newborns with neonatal encephalopathy cooled during transport to 9 neonatal intensive care units in California. Newborns who met institutional criteria for therapeutic hypothermia were randomly assigned to receive cooling according to usual center practices vs device servo-regulated cooling. The primary outcome was the percentage of temperatures in target range (33°-34°C) during transport. Secondary outcomes included percentage of newborns reaching target temperature any time during transport, time to target temperature, and percentage of newborns in target range 1 hour after cooling initiation. One hundred newborns were enrolled: 49 to control arm and 51 to device arm. Baseline demographics did not differ with the exception of cord pH. For each subject, the percentage of temperatures in the target range was calculated. Infants cooled using the device had a higher percentage of temperatures in target range compared with control infants (median 73% [IQR 17-88] vs 0% [IQR 0-52], P newborns with neonatal encephalopathy. Copyright © 2015 Elsevier Inc. All rights reserved.

Electrical transport properties of V{sub 2}O{sub 5} thin films obtained by thermal annealing of layers grown by RF magnetron sputtering at room temperature

Energy Technology Data Exchange (ETDEWEB)

Giannetta, H.M.R., E-mail: hgiann@inti.gov.ar [Centro de Micro y Nano Electrónica del Bicentenario (CMNB), Instituto Nacional de Tecnología Industrial (INTI), San Martín, Buenos Aires (Argentina); Universidad Tecnológica Nacional (UTN) — Facultad Regional Buenos Aires (FRBA) (Argentina); Calaza, C. [Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus UAB, Bellaterra, 08193 Barcelona (Spain); Lamas, D.G. [Universidad Nacional del Comahue CONICET-CITEFA — Laboratorio de Caracterización de Materiales, Facultad de Ingeniería, Neuquen (Argentina); Fonseca, L. [Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus UAB, Bellaterra, 08193 Barcelona (Spain); Fraigi, L. [Centro de Micro y Nano Electrónica del Bicentenario (CMNB), Instituto Nacional de Tecnología Industrial (INTI), San Martín, Buenos Aires (Argentina); Universidad Tecnológica Nacional (UTN) — Facultad Regional Buenos Aires (FRBA) (Argentina)

2015-08-31

The present study investigates the main electrical transport mechanism in V{sub 2}O{sub 5} thin films deposited by RF magnetron sputtering on the basis of the Mott's small polaron hopping model. The material under test was obtained at room temperature from a V{sub 2}O{sub 5} target and then oxidized at high temperature under air atmosphere to obtain the desired V{sub 2}O{sub 5} phase. The dependence of the electrical conductivity of the V{sub 2}O{sub 5} thin films with temperature was analyzed using the Mott's small polarons hopping transport model under the Schnakenberg form. Model results suggest a polaron binding energy W{sub H} = 0.1682 eV, with a structural disorder energy W{sub D} = 0.2241 eV and an optical phonon frequency ν{sub 0} = 0.468 × 10{sup 13}s{sup −1}. These results are in agreement with data reported in literature for single crystal V{sub 2}O{sub 5}. However, the carrier mobility μ = 1.5019 × 10{sup −5} cm{sup 2}/Vs computed in the non-adiabatic regime is significantly smaller than that of the single crystal, suggesting a strong electron–phonon coupling in the V{sub 2}O{sub 5} thin films obtained with the proposed deposition method. - Highlights: • A two-stage deposition method compatible with lift-off patterning is proposed. • V{sub 2}O{sub 5} films are deposited by RF magnetron sputtering and then annealed in air. • Films are analyzed by SEM and its pure phase nature is confirmed by XRD. • Electrical conductivity was fitted using Mott's model for small polarons. • Fit derived parameters confirm charge transport through small-polarons hopping.

Transport in Auxiliary Heated NSTX Discharges

International Nuclear Information System (INIS)

LeBlanc, B.P.; Bell, M.G.; Bell, R.E.; Bitte, M.L.; Bourdelle, C.; Gates, D.A.; Kaye, S.M.; Maingi, R.; Menard, J.E.; Mueller, D.; Ono, M.; Paul, S.F.; Redi, M.H.; Roquemore, A.L.; Rosenberg, A.; Sabbagh, S.A.; Stutman, D.; Synakowski, E.J.; Soukhanovskii, V.A.; Wilson, J.R.

2003-01-01

The NSTX spherical torus (ST) provides a unique platform to investigate magnetic confinement in auxiliary-heated plasmas at low aspect ratio. Auxiliary power is routinely coupled to ohmically heated plasmas by deuterium neutral-beam injection (NBI) and by high-harmonic fast waves (HHFW) launch. While theory predicts both techniques to preferentially heat electrons, experiment reveals the electron temperature is greater than the ion temperature during HHFW, but the electron temperature is less than the ion temperature during NBI. In the following we present the experimental data and the results of transport analyses

Dynamic transport study of the plasmas with transport improvement in LHD and JT-60U

International Nuclear Information System (INIS)

Ida, K.; Inagaki, S.; Sakamoto, R.; Tanaka, K.; Funaba, H.; Kubo, S.; Yoshinuma, M.; Shimozuma, T.; Takeiri, Y.; Ikeda, K.; Michael, C.; Tokuzawa, T.; Sakamoto, Yoshiteru; Takenaga, Hidenobu; Isayama, Akihiko; Ide, Shunsuke; Fujita, Takaaki

2006-10-01

A transport analysis during the transient phase of heating (a dynamic transport study) applied to the plasma with internal transport barriers (ITBs) in the Large Helical Device (LHD) heliotron and JT-60U tokamak is described. In the dynamic transport study 1) a slow transition between two transport branches is observed, 2) the time of the transition from the L-mode plasma to the ITB plasma is clearly determined by the onset of the flattening of the temperature profile in the core region and 3) a spontaneous phase transition from a weak, wide ITB to a strong, narrow ITB and its back-transition are observed. The flattening of the core region of the ITB transition and the back-transition between a wide ITB and a narrow ITB suggest the strong interaction of turbulent transport in space, where turbulence suppression at certain locations in the plasma causes the enhancement of turbulence and thermal diffusivity nearby. (author)

Photosynthetic temperature responses of tree species in Rwanda: evidence of pronounced negative effects of high temperature in montane rainforest climax species

Science.gov (United States)

Vårhammar, Angelica; Wallin, Göran; McLean, Christopher M.; Dusenge, Mirindi Eric; Medlyn, Belinda E.; Hasper, Thomas B.; Nsabimana, Donat; Uddling, Johan

2015-04-01

The sensitivity of photosynthetic metabolism to temperature has been identified as a key uncertainty for projecting the magnitude of the terrestrial feedback on future climate change. While temperature responses of photosynthetic capacities have been comparatively well investigated in temperate species, the responses of tropical tree species remain unexplored. We compared the responses of seedlings of native cold-adapted tropical montane rainforest tree species to exotic warm-adapted plantation species, all growing in an intermediate temperature common garden in Rwanda. Leaf gas exchange responses to CO2 at different temperatures (20 - 40 C) were used to assess the temperature responses of biochemical photosynthetic capacities. Analyses revealed a lower optimum temperature for photosynthetic electron transport rates than for Rubisco carboxylation rates, along with lower electron transport optima in the native cold-adapted than in the exotic warm-adapted species. The photosynthetic optimum temperatures were generally exceeded by daytime peak leaf temperatures, in particular in the native montane rainforest climax species. This study thus provides evidence of pronounced negative effects of high temperature in tropical trees and indicates high susceptibility of montane rainforest climax species to future global warming. (Reference: New Phytologist, in press)

ADVANCED CUTTINGS TRANSPORT STUDY

Energy Technology Data Exchange (ETDEWEB)

Ergun Kuru; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Neelima Godugu

2000-07-30

ACTS flow loop is now operational under elevated pressure and temperature. Currently, experiments with synthetic based drilling fluids under pressure and temperature are being conducted. Based on the analysis of Fann 70 data, empirical correlations defining the shear stress as a function of temperature, pressure and the shear rate have been developed for Petrobras synthetic drilling fluids. PVT equipment has been modified for testing Synthetic oil base drilling fluids. PVT tests with Petrobras Synthetic base mud have been conducted and results are being analyzed Foam flow experiments have been conducted and the analysis of the data has been carried out to characterize the rheology of the foam. Comparison of pressure loss prediction from the available foam hydraulic models and the test results has been made. Cuttings transport experiments in horizontal annulus section have been conducted using air, water and cuttings. Currently, cuttings transport tests in inclined test section are being conducted. Foam PVT analysis tests have been conducted. Foam stability experiments have also been conducted. Effects of salt and oil concentration on the foam stability have been investigated. Design of ACTS flow loop modification for foam and aerated mud flow has been completed. A flow loop operation procedure for conducting foam flow experiments under EPET conditions has been prepared Design of the lab-scale flow loop for dynamic foam characterization and cuttings monitoring instrumentation tests has been completed. The construction of the test loop is underway. As part of the technology transport efforts, Advisory Board Meeting with ACTS-JIP industry members has been organized on May 13, 2000.

Ion transport analysis of a high beta-poloidal JT-60U discharge

International Nuclear Information System (INIS)

Horton, W.; Tajima, T.; Dong, J.-Q.; Kim, J.-Y.; Kishimoto, Y.

1997-01-01

The high beta-poloidal discharge number 17110 in JT-60U (JT-60 Team, IAEA, Vienna, 1993) that developes an internal transport barrier is analysed for the transport of ion energy and momentum. First, the classical ion temperature gradient stability properties are calculated in the absence of sheared plasma flows to establish the L-mode transport level prior to the emergence of the transport barrier. Then the evolving toroidal and poloidal velocity profiles reported by Koide et al (1994 Phys. Rev. Lett. 72 3662) are used to show how the sheared mass flows control the stability and transport. Coupled energy-momentum transport equations predict the creation of a transport barrier. The balance of the steep ion temperature gradient against the magnetic shear and sheared mass flow is calculated for the profiles in the 17110 discharge. (Author)