Super low NO.sub.x, high efficiency, compact firetube boiler

Science.gov (United States)

Chojnacki, Dennis A.; Rabovitser, Iosif K.; Knight, Richard A.; Cygan, David F.; Korenberg, Jacob

2005-12-06

A firetube boiler furnace having two combustion sections and an in-line intermediate tubular heat transfer section between the two combustion sections and integral to the pressure vessel. This design provides a staged oxidant combustion apparatus with separate in-line combustion chambers for fuel-rich primary combustion and fuel-lean secondary combustion and sufficient cooling of the combustion products from the primary combustion such that when the secondary combustion oxidant is added in the secondary combustion stage, the NO.sub.x formation is less than 5 ppmv at 3% O.sub.2.

Anomalous Seebeck coefficient in boron carbides

International Nuclear Information System (INIS)

Aselage, T.L.; Emin, D.; Wood, C.; Mackinnon, I.D.R.; Howard, I.A.

1987-01-01

Boron carbides exhibit an anomalously large Seebeck coefficient with a temperature coefficient that is characteristic of polaronic hopping between inequivalent sites. The inequivalence in the sites is associated with disorder in the solid. The temperature dependence of the Seebeck coefficient for materials prepared by different techniques provides insight into the nature of the disorder

Exploring Charge Transport in Guest Molecule Infiltrated Cu<sub>3sub>(BTC)>2sub> Metal Organic Framework

Energy Technology Data Exchange (ETDEWEB)

Leonard, Francois Leonard [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Stavila, Vitalie [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Allendorf, Mark D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2014-09-01

The goal of this Exploratory Express project was to expand the understanding of the physical properties of our recently discovered class of materials consisting of metal-organic frameworks with electroactive ‘guest’ molecules that together form an electrically conducting charge-transfer complex (molecule@MOF). Thin films of Cu<sub>3sub>(BTC)>2sub> were grown on fused silica using solution step-by-step growth and were infiltrated with the molecule tetracyanoquinodimethane (TCNQ). The infiltrated MOF films were extensively characterized using optical microscopy, scanning electron microscopy, Raman spectroscopy, electrical conductivity, and thermoelectric properties. Thermopower measurements on TCNQ@Cu<sub>3sub>(BTC)>2sub> revealed a positive Seebeck coefficient of ~400 μV/k, indicating that holes are the primary carriers in this material. The high value of the Seebeck coefficient and the expected low thermal conductivity suggest that molecule@MOF materials may be attractive for thermoelectric power conversion applications requiring low cost, solution-processable, and non-toxic active materials.

A new hybrid two-zone/crucible furnace process for the growth of epitaxial Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} superconducting films

Energy Technology Data Exchange (ETDEWEB)

Siegal, M.P.; Overmyer, D.L.; Venturini, E.L.; Dominguez, F.; Padilla, R.R. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

1998-12-01

Epitaxial Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8} (Tl-2212) films {approximately}5500 {Angstrom} thick are grown on LaAlO{sub 3}(100) substrates using a new hybrid two-zone/crucible furnace process enabling precise control of thallination. This method combines the best features of both conventional crucible and two-zone processing for the first time: superb film properties and reduced handling of hazardous Tl-oxide powders. Single-phase, highly {ital c}-axis oriented Tl-2212 films are grown with smooth morphology, Meissner transition {approximately}103 K, and critical current density {approximately}1.1{times}10{sup 7}A/cm{sup 2} at 5 K for twenty consecutive runs without having to change or add to the Tl-oxide source. {copyright} {ital 1998 Materials Research Society.}

Self-compacting concrete with sugarcane bagasse ash – ground blast furnace slag blended cement: fresh properties

Science.gov (United States)

Le, Duc-Hien; Sheen, Yeong-Nain; Ngoc-Tra Lam, My

2018-04-01

In this investigation, major properties in fresh state of self-compacting concrete (SCC) developed from sugarcane bagasse ash and granulated blast furnace slag as supplementary cementitious materials were examined through an experimental work. There were four mix groups (S0, BA10, BA20, and BA30) containing different cement replacing levels; and totally, 12 SCC mixtures and one control mixture were provided for the test. Fresh properties of the proposed SCC were evaluated through measurement of the density, slump, slump-flow, V-funnel test, T500 slump, Box-test, and setting time. The testing results indicated that replacing either SBA and/or BFS to OPC in SCC mixtures led to lower density, lesser flowability, and longer hardening times.

Dismantling of a furnace and gloveboxes of a U{sub 3}O{sub 8} with 20% enrichment production line; Desmantelamiento de un horno y cajas de guantes de una linea de produccion de U{sub 3}O{sub 8} enriquecido al 20%

Energy Technology Data Exchange (ETDEWEB)

Yorio, Daniel; Cinat, Enrique; Cincotta, Daniel; Fernandez, Carlos A; Bruno, Hernan R; Camacho, Esteban F; Boero, Norma [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Combustibles Nucleares

1999-07-01

In the Uranium Powder Manufacturing Plant at CAC, U{sub 3}O{sub 8} with 20% enrichment is manufactured for fuel plates to be used in test reactors. This plant is in full operation since 1986, producing uranium oxide for Peru, Algeria, Iran, Egypt and the RA-3-CAE reactors. Some of the equipment of the Plant have finished their life time and one of the furnaces of the processing line had to be replaced. This work implied the dismantling not only of the furnace, but also of the gloveboxes connected to the furnace and the dismantling of the extraction lines and air injection of the gloveboxes. The work had to be performed with the necessary care in order to minimize risks and effects on personnel, installations and environment involved. (author)

Exciton Seebeck effect in molecular systems

Energy Technology Data Exchange (ETDEWEB)

Yan, Yun-An, E-mail: yunan@nano.gznc.edu.cn [Guizhou Provincial Key Laboratory of Computational Nanomaterial Science, Guizhou Normal College, Guiyang, Guizhou 550018 (China); Cai, Shaohong [Guizhou Key Laboratory of Economic System Simulation, Guizhou University of Finance and Economics, Guiyang 550004 (China)

2014-08-07

We investigate the exciton dynamics under temperature difference with the hierarchical equations of motion. Through a nonperturbative simulation of the transient absorption of a heterogeneous trimer model, we show that the temperature difference causes exciton population redistribution and affects the exciton transfer time. It is found that one can reproduce not only the exciton population redistribution but also the change of the exciton transfer time induced by the temperature difference with a proper tuning of the site energies of the aggregate. In this sense, there exists a site energy shift equivalence for any temperature difference in a broad range. This phenomenon is similar to the Seebeck effect as well as spin Seebeck effect and can be named as exciton Seebeck effect.

Graphite electrode DC arc furnace system for treatment of environmentally undesirable solid waste

International Nuclear Information System (INIS)

Titus, C.H.

1993-01-01

A gas tight DC arc furnace system using graphite electrodes is ideally suited for destruction of organic materials, compaction of metallic materials, and vitrification of inorganic waste materials. A graphite electrode DC arc furnace system which was developed by Electro-Pyrolysis, Inc. has been used to demonstrate that iron basalt soil containing various surrogate nonradioactive materials found on Department of Energy's Atomic Energy Sites and hospital waste can be reduced to a compact, vitrified, solid material which is environmentally acceptable and will pass TCLP leachate tests. A second graphite electrode DC arc furnace system is presently under construction and will be in operation at MIT during the second quarter of 1993. This furnace system is designed for demonstration of waste treatment and stabilization at a rate of 500 pounds per hour and will also be used for development and performance evaluation of diagnostic techniques and equipment for measuring and understanding internal furnace temperature profiles, gas entrained particulate composition, and particulate size distribution in various locations in the furnace during operation

A setup for measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials

Science.gov (United States)

Fu, Qiang; Xiong, Yucheng; Zhang, Wenhua; Xu, Dongyan

2017-09-01

This paper presents a setup for measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials. The sample holder was designed to have a compact structure and can be directly mounted in a standard cryostat system for temperature-dependent measurements. For the Seebeck coefficient measurement, a thin bar-shaped sample is mounted bridging two copper bases; and two ceramic heaters are used to generate a temperature gradient along the sample. Two type T thermocouples are used to determine both temperature and voltage differences between two widely separated points on the sample. The thermocouple junction is flattened into a disk and pressed onto the sample surface by using a spring load. The flexible fixation method we adopted not only simplifies the sample mounting process but also prevents thermal contact deterioration due to the mismatch of thermal expansion coefficients between the sample and other parts. With certain modifications, the sample holder can also be used for four-probe electrical resistivity measurements. High temperature measurements are essential for thermoelectric power generation. The experimental system we developed is capable of measuring the Seebeck coefficient and the electrical resistivity of bulk thermoelectric materials in a wide temperature range from 80 to 500 K, which can be further extended to even higher temperatures. Measurements on two standard materials, constantan and nickel, confirmed the accuracy and the reliability of the system.

Anisotropic transport in the quasi-one-dimensional semiconductor Li{sub 0.33}MoO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Moshfeghyeganeh, S.; Cote, A. N.; Cohn, J. L., E-mail: cohn@physics.miami.edu [Department of Physics, University of Miami, Coral Gables, Florida 33124 (United States); Neumeier, J. J. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

2016-03-07

Transport measurements (electrical resistivity, Seebeck coefficient, and thermal conductivity) in the temperature range 80–500 K are presented for single crystals of the quasi-one-dimensional (Q1D) semiconductor Li{sub 0.33}MoO{sub 3}. Opposite signs are observed for the Seebeck coefficient along the trinclinic a and c axes, with S{sub c} − S{sub a} ≃ 250 μV/K near room temperature and ≃100 μV/K at 380 K. The thermal conductivity at room temperature in the a-c planes was ∼2 W/m K and ∼10 times smaller along b*. A weak structural anomaly at T{sub s} ≈ 355 K, identified in the temperature-dependent lattice constants, coincides with anomalies in the electrical properties. Analysis of the electronic transport at T > T{sub s} favors an intrinsic semiconductor picture for transport along the most conducting Q1D axis and small-polaronic transport along the other directions, providing insight into the origin of the Seebeck anisotropy.

Magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy

Directory of Open Access Journals (Sweden)

Keyu Ning

2017-01-01

Full Text Available As one invigorated filed of spin caloritronics combining with spin, charge and heat current, the magneto-Seebeck effect has been experimentally and theoretically studied in spin tunneling thin films and nanostructures. Here we analyze the tunnel magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy (p-MTJs under various measurement temperatures. The large tunnel magneto-Seebeck (TMS ratio up to −838.8% for p-MTJs at 200 K is achieved, with Seebeck coefficient S in parallel and antiparallel states of 6.7 mV/K and 62.9 mV/K, respectively. The temperature dependence of the tunnel magneto-Seebeck can be attributed to the contributing transmission function and electron states at the interface between CoFeB electrode and MgO barrier.

Characterization of calcium carbonate sorbent particle in furnace environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang Soo [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Jung, Jae Hee [Environment Sensor System Research Center, KIST 39-1 Hawolgok-dong, Seongbuk-gu, Seoul, 136-791 (Korea, Republic of); Keel, Sang In; Yun, Jin Han; Min, Tai Jin [Environmental Systems Research Division, KIMM 104 Sinseongno, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Kim, Sang Soo, E-mail: sskim@kaist.ac.kr [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

2012-07-01

The oxy-fuel combustion system is a promising technology to control CO{sub 2} and NO{sub X} emissions. Furthermore, sulfation reaction mechanism under CO{sub 2}-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO{sub 3}) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO{sub 3}, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO{sub 3} sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO{sub 2} atmosphere due to the higher CO{sub 2} partial pressure. Instead, the sintering effect was dominant in the CO{sub 2} atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO{sub 2} atmospheres.

Numerical conversion efficiency of thermally isolated Seebeck nanoantennas

Directory of Open Access Journals (Sweden)

Edgar Briones

2016-11-01

Full Text Available In this letter, we evaluate the conversion efficiency of thermally isolated Seebeck nanoantennas by numerical simulations and discuss their uses and scope for energy harvesting applications. This analysis includes the simple case of titanium-nickel dipoles suspended in air above the substrate by a 200 nm silicon dioxide membrane to isolate the heat dissipation. Results show that substantially thermal gradients are induced along the devices leading to a harvesting efficiency around 10-4 %, 400 % higher than the previously reported Seebeck nanoantennas. In the light of these results, different optimizing strategies should be considered in order to make the Seebeck nanoantennas useful for harvesting applications.

Experimental study of volatile-N conversion at O{sub 2}/CO{sub 2} atmosphere in a drop tube furnace

Energy Technology Data Exchange (ETDEWEB)

Cao, Huali; Sun, Shaozeng; Chen, Hao; Meng, Xianyu; Wang, Dong [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Wall, Terry F. [Newcastle Univ., NSW (Australia). Chemical Engineering

2013-07-01

In coal combustion, NOx is largely formed from the oxidation of volatile nitrogen compounds such as HCN and NH{sub 3}. The experiments on the volatile-N conversion to NO at O{sub 2}/CO{sub 2} atmosphere were carried out in a drop tube furnace. The effects of the excess oxygen ratio {lambda} (0.6-1.4), temperature (1,000-1,300 C), O{sub 2}/CO{sub 2} ratio, and as well as CH{sub 4}/NH{sub 3} mole ratio were investigated. To further understand the importance of NO reburn during volatile combustion, experiments were also performed with different concentrations of background NO (0-950 ppm). The results show that volatile-N conversion to NO is sensitive to excess oxygen ratio {lambda} at strongly oxidizing atmosphere. For volatile combustion, there is an optimal temperature and inlet O{sub 2} concentration to minimize the volatile-N conversion to NO. The CH{sub 4}/NH{sub 3} mole ratio plays an important role on the NO formation under oxidizing atmosphere. High levels of background NO prohibit the volatile-N conversion to NO significantly as the volatile-N conversion ratio decreases by 19-36%. The reburn fractions of recycle NO in fuel-rich and fuel-lean condition are 14.8 and 9.8% at 1,200 C, respectively.

Thermoelectric properties of TbFe{sub 2} and TbCo{sub 2} in C15- laves phase: Spin-polarized DFT+U approach

Energy Technology Data Exchange (ETDEWEB)

Reshak, A.H., E-mail: maalidph@yahoo.co.uk [New Technologies - Research Centre, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic); School of Material Engineering, University Malaysia Perlis, Kangar, Perlis 01007 (Malaysia)

2017-01-15

Thermoelectric properties of materials are intimately related to their electronic band structure. Combining first- and second-principles calculations, we have obtained the transport properties for the spin-up and spin-down electrons of the laves phase TbFe{sub 2} and TbCo{sub 2} compounds. The unique band structure feature and the density of states at Fermi level (E{sub F}) promote the E{sub F} to a point where carriers are in energetic proximity to these features. The non-zero density of states at E{sub F} for the spin-up (↑) and spin-down (↓) electrons leads to unusual transport properties because both the (↑) and (↓) densities contributes to the states at E{sub F}. The parabolic bands in the vicinity of E{sub F} enhance the carriers mobility and hence the transport properties of TbFe{sub 2} and TbCo{sub 2}. Calculations show that the spin-up/down transport coefficients are temperature-dependent. It has been found that TbCo{sub 2} possess larger Seebeck coefficient than that of TbFe{sub 2} and hence the power factor. The calculated Seebeck coefficient of TbCo{sub 2} agree well with the available experimental data. - Highlights: • The transport properties of TbFe{sub 2} and TbCo{sub 2} are obtained. • The non-zero density of states at E{sub F} leads to unusual transport properties. • Spin-up/down transport coefficients are temperature-dependent. • The calculated Seebeck coefficient of TbCo{sub 2} agree with the experimental data. • TbCo{sub 2} possesses larger Seebeck coefficient than that of TbFe{sub 2}.

Sintering of nanopowders of ZrO{sub 2} (Y{sub 2}O{sub 3}): Effect of compaction pressure on densification; Sinterizacao de pos nanoparticulados de ZrO{sub 2} (Y{sub 2}O{sub 3}): efeito da pressao de compactacao na densificacao

Energy Technology Data Exchange (ETDEWEB)

Palmeira, Alexandre Alvarenga; Magnago, Roberto de Oliveira; Pereira, Glayce Cassaro [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Bondioli, Marcelo Jose; Strecker, Kurt [Universidade Federal Sao Joao Del-Rey (UFSJ), MG (Brazil); Santos, Claudinei dos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

2014-06-15

In this work studied the powders (nano) sintered of ZrO{sub 2} (Y{sub 2}O{sub 3}) by dilatometry. Was identified the effect of compaction pressure variation in the final results of densification of materials. Powders were compacted at different compaction pressures. The compacts were subjected to temperatures of 1250°C to 1400°C with sintering levels ranging from 0 to 8 hours. Samples were characterized by X-ray diffraction and relative density using Archimedes method. The results were compared with powders (micro) of similar composition in order to compare the effect of particle size on densification parameters. The samples were further subjected to microstructural characterization in order to identify the average grain size of the sintering under each condition used in both materials. (author)

Lead scrap processing in rotary furnaces: a review

Energy Technology Data Exchange (ETDEWEB)

Rousseau, M

1987-01-01

Formerly, the lead scrap had been processed mainly in reverberatory and shaft furnaces or, even, in rotary furnaces (R.F.). The direct smelting of battery scrap entrains an expensive pollution control and high operating costs because of slag recirculation, coke consumption, losses in slag and matte. Nowadays, mechanized battery wrecking plants allow selective separation of casings and separators from metallic Pb (grids, poles, solders) as well as lead in non-metallic form (PbSO/sub 4/, PbO, PbO/sub 2/, contaminated with some Sb) frequently called paste. Because of their high performance and flexibility in metallurgical processing (melting, reducing, oxidizing and selective pouring) the R.F. supersedes the reverberatory furnace worldwide.

Recycling ground granulated blast furnace slag as cold bonded artificial aggregate partially used in self-compacting concrete.

Science.gov (United States)

Gesoğlu, Mehmet; Güneyisi, Erhan; Mahmood, Swara Fuad; Öz, Hatice Öznur; Mermerdaş, Kasım

2012-10-15

Ground granulated blast furnace slag (GGBFS), a by-product from iron industry, was recycled as artificial coarse aggregate through cold bonding pelletization process. The artificial slag aggregates (ASA) replaced partially the natural coarse aggregates in production of self-compacting concrete (SCC). Moreover, as being one of the most widely used mineral admixtures in concrete industry, fly ash (FA) was incorporated as a part of total binder content to impart desired fluidity to SCCs. A total of six concrete mixtures having various ASA replacement levels (0%, 20%, 40%, 60%, and 100%) were designed with a water-to-binder (w/b) ratio of 0.32. Fresh properties of self-compacting concretes (SCC) were observed through slump flow time, flow diameter, V-funnel flow time, and L-box filling height ratio. Compressive strength of hardened SCCs was also determined at 28 days of curing. It was observed that increasing the replacement level of ASA resulted in decrease in the amount of superplasticizer to achieve a constant slump flow diameter. Moreover, passing ability and viscosity of SCC's enhanced with increasing the amount of ASA in the concrete. The maximum compressive strength was achieved for the SCC having 60% ASA replacement. Copyright © 2012 Elsevier B.V. All rights reserved.

High-stability Ti{sup 4+} precursor for the TiO{sub 2} compact layer of dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Yi, Qinghua; Cong, Shan; Wang, Hao; Wang, Yun; Dai, Xiao; Zhao, Jie; Sun, Yinghui; Lou, Yanhui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn

2015-11-30

Graphical abstract: - Highlights: • We developed an aqueous polymer-assisted deposition method to improve the chemical stability of the TiCl{sub 4} aqueous solution. • The Ti{sup 4+} is encapsulated by the polymer can maintain their initial performances for several months. • The film is dense, smooth and uniform, preparing by this method. • The power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. - Abstract: A compact layer (blocking layer) can effectively block the direct contact between the fluorine-doped tin oxide (FTO) glass substrate and electrolyte in dye-sensitized solar cells (DSSCs). The TiCl{sub 4} hydrolysis has been widely adopted for preparing the TiO{sub 2} compact layer (H-TiO{sub 2}). However, the TiCl{sub 4} aqueous solution is unstable for its high reactivity. To improve the chemical stability of TiCl{sub 4} aqueous solution, the Ti{sup 4+} is encapsulated by the polymer, polyethyleneimine (PEI). Experimentals show that the Ti-PEI precursor solution can maintain their initial performances for several months. The resulting TiO{sub 2} film (P-TiO{sub 2}) grown by the Ti-PEI precursor is dense, smooth and uniform without any visible and detectable cracks or voids. The P-TiO{sub 2} compact layer is even denser than the H-TiO{sub 2} compact layer, suggesting reducing the electron recombination and prolonging the electron lifetime in dye-sensitized solar cells. Indeed, the electron lifetime of the DSSC based on the P-TiO{sub 2} is 13.15 ms, which is longer than the 10.83 ms based on H-TiO{sub 2}. Meanwhile, the power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. Therefore, this encapsulation technology can not only improve the stability of the metal ions solution but also meet a large-scale fabrication demand of the TiO{sub 2} compact layer in future DSSCs.

System to Measure Thermal Conductivity and Seebeck Coefficient for Thermoelectrics

Science.gov (United States)

Kim, Hyun-Jung; Skuza, Jonathan R.; Park, Yeonjoon; King, Glen C.; Choi, Sang H.; Nagavalli, Anita

2012-01-01

The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at elevated temperatures. This has led to the implementation of nonstandardized practices that have further complicated the confirmation of reported high ZT materials. The major objective of the procedure described is for the simultaneous measurement of the Seebeck coefficient and thermal diffusivity within a given temperature range. These thermoelectric measurements must be precise, accurate, and reproducible to ensure meaningful interlaboratory comparison of data. The custom-built thermal characterization system described in this NASA-TM is specifically designed to measure the inplane thermal diffusivity, and the Seebeck coefficient for materials in the ranging from 73 K through 373 K.

Improvement of thermoelectric properties of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} films grown on graphene substrate

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Wan [Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); School of Electrical and Electronic Engineering, Yonsei University, Seoul (Korea, Republic of); Kim, Gun Hwan; Choi, Ji Woon; An, Ki-Seok; Lee, Young Kuk [Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); Kim, Jin-Sang [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Kim, Hyungjun [School of Electrical and Electronic Engineering, Yonsei University, Seoul (Korea, Republic of)

2017-06-15

A study of substrate effect on the thermoelectric (TE) properties of Bi{sub 2}Te{sub 3} (BT) and Sb{sub 2}Te{sub 3} (ST) thin films grown by plasma-enhanced chemical vapor deposition (PECVD) was performed. Graphene substrates which have small lattice mismatch with BT and ST were used for the preparation of highly oriented BT and ST thin films. Carrier mobility of the epitaxial BT and ST films grown on the graphene substrates increased as the deposition temperature increased, which was not observed in that of SiO{sub 2}/Si substrates. Seebeck coefficients of the as-grown BT and ST films were observed to be maintained even though carrier concentration increased in the epitaxial BT and ST films on graphene substrate. Although Seebeck coefficient was not improved, power factor of the as-grown BT and ST films was considerably enhanced due to the increase of electrical conductivity resulting from the high carrier mobility and moderate carrier concentration in the epitaxial BT and ST films. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Numerical modeling of the vertical hydrofluorination zone in the moving bed furnace for the production of UF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Jourde, J.; Patisson, F.; Ablitzer, D. [Ecole des Mines, Nancy (France). Lab. de Science et Genie des Materiaux Metalliques; Houzelot, J.L. [Ecole des Mines, Nancy (France). Lab. des Sciences du Genie Chimique

1996-12-31

Uranium tetrafluoride UF{sub 4} is produced in the moving bed furnace, a reactor in which solid- and gas counterflow. Due to the highly exothermic nature of the chemical reactions involved, the-reactor operation requires a careful temperature control. To provide operators with an appropriate tool for the predictive simulation, optimization and control of the process an overall numerical model of the furnace has been developed. This article describes the part of the model concerning the vertical hydrofluorination zone. The differential equations representing the mass, energy and momentum balances are solved using the finite volume method. The physicochemical parameters necessary for the calculation are detailed. The rate of the main reaction, the hydrofluorination of UO{sub 2}, has been determined with the aid of a specific kinetic model. The computed parameters, namely the temperature and solid and gas compositions, are visualized in the form of isovalue maps. The initial results reveal the influence of a thermodynamic limitation of the reaction at temperatures higher than 650 K. (author)

Numerical modeling of the vertical hydrofluorination zone in the moving bed furnace for the production of UF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Jourde, J; Patisson, F; Ablitzer, D [Ecole des Mines, Nancy (France). Lab. de Science et Genie des Materiaux Metalliques; Houzelot, J L [Ecole des Mines, Nancy (France). Lab. des Sciences du Genie Chimique

1997-12-31

Uranium tetrafluoride UF{sub 4} is produced in the moving bed furnace, a reactor in which solid- and gas counterflow. Due to the highly exothermic nature of the chemical reactions involved, the-reactor operation requires a careful temperature control. To provide operators with an appropriate tool for the predictive simulation, optimization and control of the process an overall numerical model of the furnace has been developed. This article describes the part of the model concerning the vertical hydrofluorination zone. The differential equations representing the mass, energy and momentum balances are solved using the finite volume method. The physicochemical parameters necessary for the calculation are detailed. The rate of the main reaction, the hydrofluorination of UO{sub 2}, has been determined with the aid of a specific kinetic model. The computed parameters, namely the temperature and solid and gas compositions, are visualized in the form of isovalue maps. The initial results reveal the influence of a thermodynamic limitation of the reaction at temperatures higher than 650 K. (author)

Single-phase highly densified SrBi{sub 2}Ta{sub 2}O{sub 9} compacts produced by high-pressure sintering

Energy Technology Data Exchange (ETDEWEB)

Pereira, Altair Soria; Souza, Ricson Rocha de; Sousa, Vania Caldas de, E-mail: altair@if.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre (Brazil)

2016-07-01

Full text: The development of high-performance lead-free piezoelectric ceramics is an important scientific and technological challenge, as environmental and health issues have imposed restrictions to the use of lead zirconate titanates, the most employed material in ferroelectric devices [1]. Strontium bismuth tantalate (SBT),SrBi{sub 2}Ta{sub 2}O{sub 9}, is an interesting alternative ferroelectric material as its polarization can be modified at low voltages and it shows limited polarization switching fatigue. However, the production of highly densified single-phase bulk SBT by conventional sintering procedures is strongly compromised by stoichiometric changes due to bismuth loss. In this work, high-pressure sintering has been exploited as an alternative procedure to obtain SBT highly-densified single-phase compacts. Using toroidal-type high-pressure chambers, samples were produced by reaction sintering of BiTaO{sub 4} and SrCO{sub 3} powders, mixed in the stoichiometric ratio corresponding to SrBi{sub 2}Ta{sub 2}O{sub 9}, at pressures of 2.5 GPa and 7.7 GPa, and temperatures up to 1250°C, during 10 min. X-ray diffraction and scanning electron microscopy associated to energy-dispersive X-ray spectroscopy were used to follow the phase composition and the microstructure evolution as a function of the processing conditions. A single-phase SBT compact, with a relative density of 93% and a homogeneous microstructure, was produced by sintering at 2.5 GPa/900°C [2]. References: [1] K. Panda, J. Mater. Sci. 44, 5049-5062 (2009). [2] Ricson R.Souza, Rejane K. Kirchner, Jose R. Jurado, Altair S. Pereira, Vania C. Sousa. Journal of Solid State Chemistry 233, 259-268 (2016). (author)

Electronic structure, magnetic and transport properties of the Heusler shape memory alloy Mn{sub 2}NiGa

Energy Technology Data Exchange (ETDEWEB)

Blum, C.G.F. [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz (Germany); Institute of Solid State Research, IFW Dresden, D-01171 Dresden (Germany); Ouardi, S.; Fecher, G.H.; Balke, B.; Felser, C. [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz (Germany); Wurmehl, S.; Buechner, B. [Institute of Solid State Research, IFW Dresden, D-01171 Dresden (Germany); Ueda, S.; Kobayashi, K. [NIMS Beamline Station, National Institute for Materials Science, Hyogo 679-5148, Japan. (Germany)

2011-07-01

Magnetic shape memory based on Heusler compounds have received increasing interest, due their potential use for actuator and sensor applications. The single crystals Mn{sub 2}NiGa were grown by the optical floating zone method using a image furnace with vertical setup under a purified argon atmosphere. The both cubic (austenite) and tetragonal (martensite) phases of the sample were determined using temperature dependence powder x-ray diffraction XRD. The effect of martensitic transitions on the magnetic and transport properties of the compound was investigated by measuring the saturation magnetization, electrical resistivity {rho}(T), the Seebeck coefficient S(T) and magnetoresistance R{sub M}. All measurements detect clear signatures of the martensitic transition around room temperature with a thermal hysteresis up to 30 K. The electronic structures of the martensitic as well the austenitic phase were investigated using bulk-sensitive hard X-ray photoelectron spectroscopy (HAXPES).

Multifunctional graded index TiO{sub 2} compact layer for performance enhancement in dye sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Abdullah, M.H., E-mail: abuhanifahabllh@yahoo.com [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

2013-11-01

A specially tailored index TiO{sub 2} compact layer (arc-TiO{sub 2}) has been successfully deposited to serve as photoanode of a dye-sensitized solar cell (DSSC) by radio-frequency magnetron sputtering. The employment of the TiO{sub 2} compact layer in the DSSC was systematically investigated by means of UV-absorption spectra, incident photon to current efficiency (IPCE), open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS). The higher and red-shifted transmittance spectra of the ITO/arc-TiO{sub 2} electrode mimic the IPCE spectra of the DSSC, in a specific wavelength region. Furthermore, the blue-shift of the UV-absorption spectra and lower R{sub 1} value obtained from EIS measurements implied the decrease of the charge interfacial resistance, and this consequently facilitates the charge transport from the nanocrystalline-TiO{sub 2} to the ITO. The integrated effects of the arc-TiO{sub 2} compact layer originate the remarkable improvement in this type of DSSC applications. As a result, the arc-TiO{sub 2}-based DSSC showed higher conversion efficiency of about 4.38%, representing almost 53% increment compared to bare ITO cell. This work also discuss the fundamental insight of the compact layer that determines the origin of such improvement in the DSSC performance.

K{sub 1.33}Mn{sub 8}O{sub 16} as an electrocatalyst and a cathode

Energy Technology Data Exchange (ETDEWEB)

Jalili, Seifollah, E-mail: sjalili@kntu.ac.ir [Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Computational Physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Moharramzadeh Goliaei, Elham [Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Schofield, Jeremy [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, Canada M5S 3H6 (Canada)

2017-02-15

Density functional theory (DFT) calculations are carried out to investigate the electronic, magnetic and thermoelectric properties of bulk and nanosheet K{sub 1.33}Mn{sub 8}O{sub 16} materials. The catalytic activity and cathodic performance of bulk and nanosheet structures are examined using the Tran-Blaha modified Becke-Johnson (TB-mBJ) exchange potential. Electronic structure calculations reveal an anti-ferromagnetic ground state, with a TB-mMBJ band gap in bulk K{sub 1.33}Mn{sub 8}O{sub 16} that is in agreement with experimental results. Density of state plots indicate a partial reduction of Mn{sup 4+} ions to Mn{sup 3+}, without any obvious sign of Jahn-Teller distortion. Moreover, use of the O p-band center as a descriptor of catalytic activity suggests that the nanosheet has enhanced catalytic activity compared to the bulk structure. Thermoelectric parameters such as the Seebeck coefficient, electrical conductivity, and thermal conductivity are also calculated, and it is found that the Seebeck coefficients decrease with increasing temperature. High Seebeck coefficients for both spin-up and spin-down states are found in the nanosheet relative to their value in the bulk K{sub 1.33}Mn{sub 8}O{sub 16} structure, whereas the electrical and thermal conductivity are reduced relative to the bulk. In addition, figures of merit values are calculated as a function of the chemical potential and it is found that the nanosheet has a figure of merit of ~1 at room temperature, compared to 0.5 for the bulk material. All results suggest that K{sub 1.33}Mn{sub 8}O{sub 16} nanosheets can be used both as a material in waste heat recovery and as an electrocatalyst in fuel cells and batteries. - Graphical abstract: K{sub 1.33}Mn{sub 8}O{sub 16}: bulk and nanosheet. - Highlights: • Electronic properties of bulk and nanosheet forms of K{sub 1.33}Mn{sub 8}O{sub 16} have been studied. • The K{sub 1.33}Mn{sub 8}O{sub 16} nanosheet is a semiconductor while the bulk is a metal. • K{sub

(U) Influence of Compaction Model Form on Planar and Cylindrical Compaction Geometries

Energy Technology Data Exchange (ETDEWEB)

Fredenburg, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carney, Theodore Clayton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fichtl, Christopher Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ramsey, Scott D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2018-01-05

The dynamic compaction response of CeO<sub>2sub> is examined within the frameworks of the Ramp and P-a compaction models. Hydrocode calculations simulating the dynamic response of CeO<sub>2sub> at several distinct pressures within the compaction region are investigated in both planar and cylindrically convergent geometries. Findings suggest additional validation of the compaction models is warranted under complex loading configurations.

Generation of pure spin currents via spin Seebeck effect in self-biased hexagonal ferrite thin films

Energy Technology Data Exchange (ETDEWEB)

Li, Peng; Ellsworth, David; Chang, Houchen; Janantha, Praveen; Richardson, Daniel; Phillips, Preston; Vijayasarathy, Tarah; Wu, Mingzhong, E-mail: mwu@lamar.colostate.edu [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Shah, Faisal [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-12-15

Light-induced generation of pure spin currents in a Pt(2.5 nm)/BaFe{sub 12}O{sub 19}(1.2 μm)/sapphire(0.5 mm) structure is reported. The BaFe{sub 12}O{sub 19} film had strong in-plane uniaxial anisotropy and was therefore self-biased. Upon exposure to light, a temperature difference (ΔT) was established across the BaFe{sub 12}O{sub 19} thickness that gave rise to a pure spin current in the Pt via the spin Seebeck effect. Via the inverse spin Hall effect, the spin current produced an electric voltage across one of the Pt lateral dimensions. The voltage varied with time in the same manner as ΔT and flipped its sign when the magnetization in BaFe{sub 12}O{sub 19} was reversed.

The role of SiO2 nanoparticles and ground granulated blast furnace slag admixtures on physical, thermal and mechanical properties of self compacting concrete

International Nuclear Information System (INIS)

Nazari, Ali; Riahi, Shadi

2011-01-01

Research highlights: → Nanoparticles in concrete. → Ground granulated blast furnace slag as concrete's binder. → Mechanical properties of concrete specimens by non-traditional admixtures. - Abstract: In this work, strength assessments and percentage of water absorption of self compacting concrete containing ground granulated blast furnace slag and SiO 2 nanoparticles as binder have been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impacts the physical and mechanical properties of concrete at early ages of curing, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt% at later ages. SiO 2 nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of ground granulated blast furnace slag and physical and mechanical properties of the specimens were measured. SiO 2 nanoparticle as a partial replacement of cement up to 3.0 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH) 2 amount at the early ages and hence increase strength and improve the resistance to water permeability of concrete specimens. The increased SiO 2 nanoparticles' content by more than 3.0 wt%, causes the reduced strength because of the decreased crystalline Ca(OH) 2 content required for C-S-H gel formation. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that SiO 2 nanoparticles could improve mechanical and physical properties of the concrete

Comparison of a burning mass ceramics coating in laboratory furnace and instrustrial furnace; Comparacao de queimas de uma massa ceramica de revestimento em forno de laboratorio e forno industrial

Energy Technology Data Exchange (ETDEWEB)

Soares, R.A.L., E-mail: robertoarruda@ifpi.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia do Piaui (IFPI), Terersina, PI (Brazil); Castro, J.R. de S. [Universidade Federal do Piaui (UFPI), Teresina, PI (Brazil)

2012-07-01

This work intends to analyze the differences obtained in the technological properties of a ceramic coating after firing in two distinct environments, laboratory furnace and industrial furnace. For this, was characterized a ceramic mass used in the production of porous coating. The analyzes were performed chemical, mineralogical and thermal mass in that. The specimens were obtained by compacting and burned in the maximum temperature of 1140 deg C in two furnaces, laboratory and industrial. The technological tests were performed linear shrinkage, water absorption, bulk density and mechanical strength. The microstructure was evaluated by ray-X diffraction and scanning electron microscopy. The results showed that both furnaces provided significant differences in analyzed specimens, such as increased strength and low water absorption in the fired samples in a laboratory furnace, for example. (author)

Thermoelectric properties of M{sub 2}Mo{sub 6}Se{sub 6} (M =Tl,In)

Energy Technology Data Exchange (ETDEWEB)

Verebelyi, D T; Payne, J E; Tessema, G X; Mengistu, E

1997-07-01

The authors have measured the thermal conductivity of Tl{sub 2}Mo{sub 6}Se{sub 6}, a quasi-one dimensional conductor which belongs to the family of M{sub 2}Mo{sub 6}X{sub 6} linear chain compounds. Using these results and the measurements of the Seebeck coefficient and the electrical conductivity the authors estimate the dimensionless figure of merit to be of the order of 0.08. This result suggest that this compound and other related compounds are good potential TE.

Microstructural, thermal, physical and mechanical behavior of the self compacting concrete containing SiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Nazari, Ali, E-mail: alinazari84@aut.ac.ir [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of); Riahi, Shadi [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of)

2010-11-15

Research highlights: {yields} TiO{sub 2} nanoparticles effects on flexural strength of self compacting concrete. {yields} Physical and microstructural consideration. {yields} Mechanical tests. {yields} Thermal analysis. {yields} Porosimetry. - Abstract: In the present study, flexural strength, thermal properties and microstructure of self compacting concrete with different amount of SiO{sub 2} nanoparticles has been investigated. SiO{sub 2} nanoparticles with the average particle size of 15 nm were partially added to self compacting concrete and various behaviors of the specimens have been measured. The results indicate that SiO{sub 2} nanoparticles are able to improve the flexural strength of self compacting concrete and recover the negative effects of superplasticizer on flexural strength of the specimens. SiO{sub 2} nanoparticle as a partial replacement of cement up to 4 wt% could accelerate C-S-H gel formation as a result of the increased crystalline Ca(OH){sub 2} amount at the early ages of hydration. The increased the SiO{sub 2} nanoparticles' content more than 4 wt%, causes the reduced the flexural strength because of unsuitable dispersion of nanoparticles in the concrete matrix. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of peaks related to hydrated products in X-ray diffraction results, all also indicate that SiO{sub 2} nanoparticles up to 4 wt% could improve the mechanical and physical properties of the specimens. Finally, SiO{sub 2} nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.

Construction of the vibrator for UO{sub 2} powder compacting; Izrada vibratora za kompaktiranje praha UO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Vrgora, M [Institute of Nuclear Sciences Boris Kidric, Laboratorija za termotehniku reaktora, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

This report contains the description and the scheme of the device for vibration compacting of sintered UO{sub 2} powder. This device was designed and constructed in the Department for reactor materials.

Accelerated Carbonation of Steel Slag Compacts: Development of High-Strength Construction Materials

Energy Technology Data Exchange (ETDEWEB)

Quaghebeur, Mieke; Nielsen, Peter, E-mail: peter.nielsen@vito.be; Horckmans, Liesbeth [Sustainable Materials Management, VITO, Mol (Belgium); Van Mechelen, Dirk [RECMIX bvba, Genk (Belgium)

2015-12-17

Mineral carbonation involves the capture and storage of carbon dioxide in carbonate minerals. Mineral carbonation presents opportunities for the recycling of steel slags and other alkaline residues that are currently landfilled. The Carbstone process was initially developed to transform non-hydraulic steel slags [stainless steel (SS) slag and basic oxygen furnace (BOF) slags] in high-quality construction materials. The process makes use of accelerated mineral carbonation by treating different types of steel slags with CO{sub 2} at elevated pressure (up to 2 MPa) and temperatures (20–140°C). For SS slags, raising the temperature from 20 to 140°C had a positive effect on the CO{sub 2} uptake, strength development, and the environmental properties (i.e., leaching of Cr and Mo) of the carbonated slag compacts. For BOF slags, raising the temperature was not beneficial for the carbonation process. Elevated CO{sub 2} pressure and CO{sub 2} concentration of the feed gas had a positive effect on the CO{sub 2} uptake and strength development for both types of steel slags. In addition, the compaction force had a positive effect on the strength development. The carbonates that are produced in situ during the carbonation reaction act as a binder, cementing the slag particles together. The carbonated compacts (Carbstones) have technical properties that are equivalent to conventional concrete products. An additional advantage is that the carbonated materials sequester 100–150 g CO{sub 2}/kg slag. The technology was developed on lab scale by the optimization of process parameters with regard to compressive strength development, CO{sub 2} uptake, and environmental properties of the carbonated construction materials. The Carbstone technology was validated using (semi-)industrial equipment and process conditions.

An update on blast furnace granular coal injection

Energy Technology Data Exchange (ETDEWEB)

Hill, D.G. [Bethlehem Steel Corp., Burns Harbor, IN (United States); Strayer, T.J.; Bouman, R.W. [Bethlehem Steel Corp., PA (United States)

1997-12-31

A blast furnace coal injection system has been constructed and is being used on the furnace at the Burns Harbor Division of Bethlehem Steel. The injection system was designed to deliver both granular (coarse) and pulverized (fine) coal. Construction was completed on schedule in early 1995. Coal injection rates on the two Burns Harbor furnaces were increased throughout 1995 and was over 200 lbs/ton on C furnace in September. The injection rate on C furnace reached 270 lbs/ton by mid-1996. A comparison of high volatile and low volatile coals as injectants shows that low volatile coal replaces more coke and results in a better blast furnace operation. The replacement ratio with low volatile coal is 0.96 lbs coke per pound of coal. A major conclusion of the work to date is that granular coal injection performs very well in large blast furnaces. Future testing will include a processed sub-bituminous coal, a high ash coal and a direct comparison of granular versus pulverized coal injection.

Technical aspects of acid dew point measurement in furnace exhaust. Messtechnik fuer die Saeuretaupunktmessung in Feuerungsabgasen

Energy Technology Data Exchange (ETDEWEB)

Struschka, M.; Baumbach, G.

1986-01-01

SO/sub 3/ formation in flue gases and the effect of furnace parameters, furnace type and design on the efficiency of SO/sub 2/ conversion were investigated in a detailed bibliographic study. Phase equilibrium data for the binary system H/sub 2/SO/sub 4//H/sub 2/O and equations for calculating the acid dew point are presented, and the available wet chemical methods for SO/sub 3/ concentration measurements in flue gases are reviewed. The SM1 acid dew point measuring instrument availabe at the authors' institute was modified by installing a new measuring probe, an external thermoelement intensifier, and a new PD control element for temperature control in the measuring surfaces. Acid dew point measurements were carried out in two different furnaces, i.e. a domestic boiler for light fuel oil and an industrial furnace fuelled with heavy oil at the Stuttgart University heat- and power plant. The measurements are compared with data from relevant publications. (orig./RB) With 80 figs., 7 tabs.

Effect of Pressurizing during Compaction and Sintering on the Formation of Reaction-Bonded SiC–Ti{sub 3}SiC{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun-Han; Jung, Yang-Il; Rhee, Young-Woo; Park, Dong-Jun; Park, Jung-Hwan; Park, Jeong-Yong; Kim, Hyun-Gil; Koo, Yang-Hyun [LWR Fuel Technology Division, KAERI, Daejeon (Korea, Republic of)

2016-05-15

A reaction-bonded SiC-Ti{sub 3}SiC{sub 2} ceramic composite was produced for use in a ceramic-metal composite cladding tube. The diffusion reaction between TiC and Si was investigated with respect to process pressure. The mole-fraction of TiC and Si was controlled to be 3:2 to obtain a Ti{sub 3}SiC{sub 2} phase in the ceramic composite. Sintering was conducted at 1450 °C where TiC particles could react with melted Si. SiC ceramic composites consisting of Ti{sub 3}SiC{sub 2} and TiSi{sub 2} matrix phases were obtained. The formation of the constituent phases was strongly related to the processing pressure. The number of second phases in the SiC-Ti{sub 3}SiC{sub 2} composite was controlled by adjusting the processing pressure. When the powder compacts were not pressurized, no Ti{sub 3}SiC{sub 2} phase was formed. However, the Ti{sub 3}SiC{sub 2} phase was formed under pressurizing during compaction and/or sintering. The higher the pressure the higher the purity of SiC-Ti{sub 3}SiC{sub 2}. The dual-phased SiC-Ti{sub 3}SiC{sub 2} composite, however, revealed the decreased resistance to high-temperature oxidation. It is suggested that the incorporation of TiSi{sub 2} in the composite increases the oxidation resistance as well as mechanical property.

How to control spin-Seebeck current in a metal-quantum dot-magnetic insulator junction

Science.gov (United States)

Fu, Hua-Hua; Gu, Lei; Wu, Ruqian

The control of the spin-Seebeck current is still a challenging task for the development of spin caloritronic devices. Here, we construct a spin-Seebeck device by inserting a quantum dot (QD) between the metal lead and magnetic insulator. Using the slave-particle approach and noncrossing approximation, we find that the spin-Seebeck effect increases significantly when the energy level of the QD locates near the Fermi level of the metal lead due to the enhancement of spin flipping and occurrences of quantum resonance. Since this can be easily realized by applying a gate voltage in experiments, the spin-Seebeck device proposed here can also work as a thermovoltaic transistor. Moreover, the optimal correlation strength and the energy level position of the QD are discussed to maximize the spin-Seebeck current as required for applications in controllable spin caloritronic devices.

Multi-fuel furnace. Demonstration project. Final rapport; Multibraendselsovn - Demonstrationsprojekt. Slutrapport

Energy Technology Data Exchange (ETDEWEB)

Dall Bentzen, J.

2012-06-15

It has been verified that the Dall Energy Furnace have unique features: - The furnace will accept biomass fuel with moisture content in range 20% to 60% and still keep the flue gas temperature within +-10 deg. Celsius (for pre-set temperature 900 to 975 deg. Celsius); - The ash quality from the furnace is very good with no excessive sintering and without carbon in the ash; - Flue gas dust content at the furnace exit is below 50 mg/Nm3, while the content of NO{sub x} and CO is below 175 mg/Nm3 and 20 mg/Nm3, respectively. The Dall Energy biomass furnace consists of two separate stages which are combined in a single aggregate: an updraft gasification process and a gas combustion process. As the furnace is refractory lined and as the furnace can operate at low excess air it is possible to burn biomass with water content above 60%. No mechanical parts are used at temperatures above 200 deg. Celsius. This provides a very rugged system. In the gasifier section a combustible gas is produced with a low velocity at the top of the gasifier bed. This gas is combusted to a flue gas with extremely low dust content. Also, the NO{sub x} and CO content is very low. The temperature of the flue gas at the exit is kept low by injecting water spray together with the secondary air. (Author)

OPTIMIZED FUEL INJECTOR DESIGN FOR MAXIMUM IN-FURNACE NOx REDUCTION AND MINIMUM UNBURNED CARBON

Energy Technology Data Exchange (ETDEWEB)

SAROFIM, A F; LISAUSKAS, R; RILEY, D; EDDINGS, E G; BROUWER, J; KLEWICKI, J P; DAVIS, K A; BOCKELIE, M J; HEAP, M P; PERSHING, D

1998-01-01

Reaction Engineering International (REI) has established a project team of experts to develop a technology for combustion systems which will minimize NO x emissions and minimize carbon in the fly ash. This much need technology will allow users to meet environmental compliance and produce a saleable by-product. This study is concerned with the NO x control technology of choice for pulverized coal fired boilers,"in-furnace NO<sub>x> control," which includes: staged low-NO<sub>x> burners, reburning, selective non-catalytic reduction (SNCR) and hybrid approaches (e.g., reburning with SNCR). The program has two primary objectives: 1) To improve the performance of "in-furnace" NO<sub>x> control, processes. 2) To devise new, or improve existing, approaches for maximum "in-furnace" NO<sub>x> control and minimum unburned carbon. The program involves: 1) fundamental studies at laboratory- and bench-scale to define NO reduction mechanisms in flames and reburning jets; 2) laboratory experiments and computer modeling to improve our two-phase mixing predictive capability; 3) evaluation of commercial low-NO<sub>x> burner fuel injectors to develop improved designs, and 4) demonstration of coal injectors for reburning and low-NO<sub>x> burners at commercial scale. The specific objectives of the two-phase program are to: 1 Conduct research to better understand the interaction of heterogeneous chemistry and two phase mixing on NO reduction processes in pulverized coal combustion. 2 Improve our ability to predict combusting coal jets by verifying two phase mixing models under conditions that simulate the near field of low-NO<sub>x> burners. 3 Determine the limits on NO control by in-furnace NO<sub>x> control technologies as a function of furnace design and coal type. 5 Develop and demonstrate improved coal injector designs for commercial low-NO<sub>x> burners and coal reburning systems. 6 Modify the char burnout model in REI's coal

Seebeck coefficient of synthesized Titanium Dioxide thin film on FTO glass substrate

Science.gov (United States)

Usop, R.; Hamed, N. K. A.; Megat Hasnan, M. M. I.; Ikeda, H.; Sabri, M. F. M.; Ahmad, M. K.; Said, S. M.; Salleh, F.

2018-04-01

In order to fabricate a thermoelectric device on glass substrate for harvesting waste heat energy through house appliances, the Seebeck coefficient of translucent TiO2 thin film was investigated. The TiO2 thin film was synthesized by using hydrothermal method with F-SnO2 coated glass as substrate. From scanning electron microscopy analysis, the synthesized TiO2 thin film was found to be in nanometer-scale rod structure with a thickness of 4 µm. The Seebeck coefficient was measured in the temperature range of 300 – 400 K. The Seebeck coefficient is found to be in negative value which shows that synthesized film is an n-type semiconductor material, and is lower than the value of bulk-size material. This reduction in Seebeck coefficient of TiO2 thin film is likely due to the low dimensional effect and the difference of carrier concentration.

Effect of ball milling and dynamic compaction on magnetic properties of Al{sub 2}O{sub 3}/Co(P) composite particles

Energy Technology Data Exchange (ETDEWEB)

Denisova, E. A. [Kirensky Institute of Physics SB RAS, Krasnoyarsk (Russian Federation); Krasnoyarsk Institute of Railways Transport, Krasnoyarsk (Russian Federation); Kuzovnikova, L. A. [Krasnoyarsk Institute of Railways Transport, Krasnoyarsk (Russian Federation); Iskhakov, R. S., E-mail: rauf@iph.krasn.ru; Eremin, E. V. [Kirensky Institute of Physics SB RAS, Krasnoyarsk (Russian Federation); Bukaemskiy, A. A. [Institut fur Sicherheitsforschung und Reaktortechnik, D-52425 Juelich (Germany); Nemtsev, I. V. [Krasnoyarsk Scientific Center SB RAS, Krasnoyarsk (Russian Federation)

2014-05-07

The evolution of the magnetic properties of composite Al{sub 2}O{sub 3}/Co(P) particles during ball milling and dynamic compaction is investigated. To prepare starting composite particles, the Al{sub 2}O{sub 3} granules were coated with a Co{sub 95}P{sub 5} shell by electroless plating. The magnetic and structural properties of the composite particles are characterized by scanning electron microscopy, X-ray diffraction, and the use of the Physical Property Measurement System. The use of composite core-shell particles as starting powder for mechanoactivation allows to decrease treatment duration to 1 h and to produce a more homogeneous bulk sample than in the case of the mixture of Co and Al{sub 2}O{sub 3} powders. The magnetic properties of the milled composite particles are correlated with changes in the microstructure. Reduction in grain size of Co during milling leads to an increase of the volume fraction of superparamagnetic particles and to a decrease of the saturation magnetization. The local magnetic anisotropy field depends on the amount of hcp-Co phase in sample. The anisotropy field value decreases from 8.4 kOe to 3.8 kOe with an increase in milling duration up to 75 min. The regimes of dynamic compaction were selected so that the magnetic characteristics—saturation magnetization and coercive field—remained unchanged.

Enhanced thermoelectric properties in p-type Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} alloy by combining incorporation and doping using multi-scale CuAlO{sub 2} particles

Energy Technology Data Exchange (ETDEWEB)

Song, Zijun; Liu, Yuan; Zhou, Zhenxing; Lu, Xiaofang; Wang, Lianjun [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); Zhang, Qihao [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Jiang, Wan [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen (China); Chen, Lidong [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China)

2017-01-15

Multi-scale CuAlO{sub 2} particles are introduced into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix to synergistically optimize the electrical conductivity, Seebeck coefficient, and the lattice thermal conductivity. Cu element originating from fine CuAlO{sub 2} grains diffuses into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix and tunes the carrier concentration while the coarse CuAlO{sub 2} particles survive as the second phase within the matrix. The power factor is improved at the whole temperatures range due to the low-energy electron filtering effect on Seebeck coefficient and enhanced electrical transport property by mild Cu doping. Meanwhile, the remaining CuAlO{sub 2} inclusions give rise to more boundaries and newly built interfaces scattering of heat-carrying phonons, resulting in the reduced lattice thermal conductivity. Consequently, the maximum ZT is found to be enhanced by 150% arising from the multi-scale microstructure regulation when the CuAlO{sub 2} content reaches 0.6 vol.%. Not only that, but the ZT curves get flat in the whole temperature range after introducing the multi-scale CuAlO{sub 2} particles, which leads to a remarkable increase in the average ZT. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Estimation of slagging in furnaces; Kuonaavuuden ennustaminen kivihiilen poelypoltossa

Energy Technology Data Exchange (ETDEWEB)

Jacobson, T; Jaeaeskelaeinen, K; Oeini, J; Koskiahde, A; Jokiniemi, J; Pyykkoenen, J [Imatran Voima Oy, Vantaa (Finland)

1997-10-01

Understanding and estimation of slagging in furnaces is essential in the design of new power plants with high steam values or in modifications like low-NO{sub x} retrofits in existing furnaces. Major slagging yields poor efficiency, difficult operation and high maintenance costs of the plant. The aim of the project is to develop a computational model for slagging in pulverized coal combustion. The model is based on Computer Controlled Scanning Electron Microscopy (CCSEM) analysis of mineral composition of the coal and physical models for behaviour of minerals inside a furnace. The analyzed mineral particles are classified to five composition classes and distributed to calculational coal particles if internal minerals of coal. The calculational coal particles and the external minerals are traced in the furnace to find out the behaviour of minerals inside the furnace. If the particle tracing indicates that the particle hits the heat transfer surface of the furnace the viscosity of the particle is determined to see if particle is sticky. The model will be implemented to 3D computational fluid dynamics based furnace simulation environment Ardemus which predicts the fluid dynamics, heat transfer and combustion in a furnace. (orig.)

Physics Colloquium: Theory of the spin wave Seebeck effect in magnetic insulators

CERN Multimedia

Université de Genève

2011-01-01

Geneva University Physics Department 24, quai Ernest-Ansermet CH-1211 Geneva 4 Lundi 28 février 2011 17h00 - École de Physique, Auditoire Stückelberg Theory of the spin wave Seebeck effect in magnetic insulators Prof. Gerrit Bauer Delft University of Technology The subfield of spin caloritronics addresses the coupling of heat, charge and spin currents in nanostructures. In the center of interest is here the spin Seebeck effect, which was discovered in an iron-nickel alloy. Uchida et al. recently observed the effect also in an electrically insulating Yttrium Iron Garnett (YIG) thin magnetic film. To our knowledge this is the first observation of a Seebeck effect generated by an insulator, implying that the physics is fundamentally different from the conventional Seebeck effect in metals. We explain the experiments by the pumping of a spin current into the detecting contacts by the thermally excited magnetization dynamics. In this talk I will give a brief overview over the state o...

Crystal structure and thermoelectric properties of clathrate, Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}: Small cage volume and large disorder of the guest atom

Energy Technology Data Exchange (ETDEWEB)

Roudebush, John H., E-mail: jhr@princeton.edu [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States); Orellana, Mike [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States); Bux, Sabah [Thermal Energy Conversion Technologies Group, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States); Yi Tanghong; Kauzlarich, Susan M. [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States)

2012-08-15

Samples with the type-I clathrate composition Ba{sub 8}Ni{sub x}Si{sub 46-x} have been synthesized and their structure and thermoelectric properties characterized. Microprobe analysis indicates the Ni incorporation to be 2.62{<=}x{<=}3.53. The x=3.5 phase crystallizes in the type-I clathrate structure (space group: Pm-3n) with a lattice parameter of 10.2813(3) A. The refined composition was Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}, with small vacancies, 0.4 and 0.5 atoms per formula unit, at the 2a and 6c sites, respectively. The position of the Ba2 atom in the large cage was modeled using a 4-fold split position (24j site), displaced 0.18 A from the cage center (6d site). The volume of the large cage is calculated to be 146 A{sup 3}, smaller than other clathrates with similar cation displacement. The sample shows n-type behavior with a maximum of -50 {mu}V/K at 823 K above which the Seebeck coefficient decreases, suggesting mixed carriers. Lattice thermal conductivity, {kappa}{sub l}, is 55 mW/K above 600 K. - Graphical abstract: Seebeck coefficient and resistivity of the type-I clathrate Ba{sub 8}Ni{sub 3.5}Si{sub 41.0}. Structure show's large displacement of the Ba cation in the large cage (6c site). Highlights: Black-Right-Pointing-Pointer Crystal structure of the Ba{sub 8}Ni{sub 3.5}Si{sub 41.0} reported. Black-Right-Pointing-Pointer Vacancies at the 2a and 6c sites. Black-Right-Pointing-Pointer Large disorder of Ba guest atom, 0.18 A from cage center. Black-Right-Pointing-Pointer Structure is compared to Ba{sub 8}Si{sub 46} and other type-I clathrates. Black-Right-Pointing-Pointer Max Seebeck of -50.7 {mu}V/C at 798.4 K, thermal conductivity {approx}55 mW/K.

YRh{sub 2}Ga. A new intergrowth variant of MgNi{sub 2} and CeCo{sub 3}B{sub 2} related slabs

Energy Technology Data Exchange (ETDEWEB)

Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2017-09-01

The gallide YRh{sub 2}Ga was synthesized by melting of the elements in an arc-furnace followed by annealing in a sealed silica tube in an induction furnace. YRh{sub 2}Ga crystallizes with a new structure type: P6{sub 3}/mmc, a=552.2(1), c=3119.5(6) pm, wR=0.0957, 497 F{sup 2} values, and 34 variables. It is the n=1 member of the RE{sub 2+n}T{sub 3+3n}X{sub 1+2n} structure series with Laves phase (MgNi{sub 2} type in the present case) and CaCu{sub 5} (CeCo{sub 3}B{sub 2} type in the present case) related slabs in the Parthe intergrowth concept.

Baking process of thin plate carbonaceous compact

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Yoshio; Shimada, Toyokazu

1987-06-27

As a production process of a thin plate carbonaceous compact for separator of phosphoric acid fuel cell, there is a process to knead carbonaceous powder and thermosetting resin solution, to form and harden the kneaded material and then to bake, carbonize and graphitize it. However in this baking and carbonization treatment, many thin plate compacts are set in a compiled manner within a heating furnace and receive a heat treatment from their circumference. Since the above compacts to be heated tend generally to be heated from their peripheries, their baked conditions are not homogeneous easily causing the formation of cracks, etc.. As a process to heat and bake homogeneously by removing the above problematical points, this invention offers a process to set in a heating furnace a laminate consisting of the lamination of thin plate carbonaceous compacts and the heat resistant soaking plates which hold the upper and lower ends of the above lamination, to fill the upper and under peripheries of the laminate above with high heat conductive packing material and its side periphery with low heat conductive packing material respectively and to heat and sinter it. In addition, the invention specifies the high and low heat conductive packing materials respectively. (1 fig, 2 tabs)

Thermoelectric performance of spin Seebeck effect in Fe3O4/Pt-based thin film heterostructures

Directory of Open Access Journals (Sweden)

R. Ramos

2016-10-01

Full Text Available We report a systematic study on the thermoelectric performance of spin Seebeck devices based on Fe3O4/Pt junction systems. We explore two types of device geometries: a spin Hall thermopile and spin Seebeck multilayer structures. The spin Hall thermopile increases the sensitivity of the spin Seebeck effect, while the increase in the sample internal resistance has a detrimental effect on the output power. We found that the spin Seebeck multilayers can overcome this limitation since the multilayers exhibit the enhancement of the thermoelectric voltage and the reduction of the internal resistance simultaneously, therefore resulting in significant power enhancement. This result demonstrates that the multilayer structures are useful for improving the thermoelectric performance of the spin Seebeck effect.

Comparison of the magneto-Peltier and magneto-Seebeck effects in magnetic tunnel junctions

NARCIS (Netherlands)

Shan, J.; Dejene, F. K.; Leutenantsmeyer, J. C.; Flipse, J.; Munzenberg, M.; van Wees, B. J.

2015-01-01

Understanding heat generation and transport processes in a magnetic tunnel junction (MTJ) is a significant step towards improving its application in current memory devices. Recent work has experimentally demonstrated the magneto-Seebeck effect in MTJs, where the Seebeck coefficient of the junction

Development of vacuum brazing furnace

International Nuclear Information System (INIS)

Singh, Rajvir; Yedle, Kamlesh; Jain, A.K.

2005-01-01

In joining of components where welding process is not possible brazing processes are employed. Value added components, high quality RF systems, UHV components of high energy accelerators, carbide tools etc. are produced using different types of brazing methods. Furnace brazing under vacuum atmosphere is the most popular and well accepted method for production of the above mentioned components and systems. For carrying out vacuum brazing successfully it is essential to have a vacuum brazing furnace with latest features of modern vacuum brazing technology. A vacuum brazing furnace has been developed and installed for carrying out brazing of components of copper, stainless steel and components made of dissimilar metals/materials. The above furnace has been designed to accommodate jobs of 700mm diameter x 2000mm long sizes with job weight of 500kgs up to a maximum temperature of 1250 degC at a vacuum of 5 x 10 -5 Torr. Oil diffusion pumping system with a combination of rotary and mechanical booster pump have been employed for obtaining vacuum. Molybdenum heating elements, radiation shield of molybdenum and Stainless Steel Grade 304 have been used. The above furnace is computer controlled with manual over ride facility. PLC and Pentium PC are integrated together to maneuver steps of operation and safety interlocks of the system. Closed loop water supply provides cooling to the system. The installation of the above system is in final stage of completion and it will be ready for use in next few months time. This paper presents insights of design and fabrication of a modern vacuum brazing furnace and its sub-system. (author)

Low-temperature processed SnO{sub 2} compact layer for efficient mesostructure perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Duan, Jinxia; Xiong, Qiu; Feng, Bingjie; Xu, Yang; Zhang, Jun; Wang, Hao, E-mail: nanoguy@126.com

2017-01-01

Highlights: • Low-temperature processed 70 nm cl-SnO{sub 2} device exhibits maximum PCE. • Champion PSC after SnCl{sub 4} treatment acquires PCE of 15.07%. • Cl-SnO{sub 2} PSC via SnCl{sub 4} treatment exhibits superior stability to cl-TiO{sub 2} based PSC. - Abstract: SnO{sub 2} nanoparticle film has been synthesized via low- temperature (∼180 °C) solution-processing and proposed as compact layer in mesostructure perovskite-type solar cell (PSC). Low-temperature processed SnO{sub 2} compact layer (cl-SnO{sub 2}) brings perfect crystal-lattice and band-gap matching between electron selective layer and FTO substrate and close interface-contact between cl-SnO{sub 2} and mesoporous TiO{sub 2} layer (mp-TiO{sub 2}), which contributes to suppressing carrier recombination and optimizing device performance. In varied thickness cells, 70 nm cl-SnO{sub 2} device exhibits maximum power conversion efficiency (PCE). In order to further restrain photoelectron recombination and improve the photovoltaic performance, the surface modification of cl-SnO{sub 2} by SnCl{sub 4} aqueous solution has been carried out. The recombination behavior in the cell interior is greatly retarded via SnCl{sub 4} treatment and champion PSC after SnCl{sub 4} treatment has acquire PCE of 15.07%, which is higher than PCE of cl-TiO{sub 2} based PSC fabricated with same mp-TiO{sub 2} and perovskite procedures (13.3%). The stability of cl-SnO{sub 2} PSC via SnCl{sub 4} treatment has also been measured and its PCE reduces to 13.0% after 2 weeks in air.

Effect of preparation procedure and nanostructuring on the thermoelectric properties of the lead telluride-based material system AgPb{sub m}BiTe{sub 2+m} (BLST-m)

Energy Technology Data Exchange (ETDEWEB)

Falkenbach, Oliver; Koch, Guenter; Schlecht, Sabine [Institute for Inorganic and Analytical Chemistry, Justus-Liebig-University, Heinrich-Buff-Ring 17, D-35392 Giessen (Germany); Schmitz, Andreas [Institute of Materials Research, German Aerospace Center (DLR), D-51170 Cologne (Germany); Hartung, David; Klar, Peter J. [Institute of Experimental Physics I, Justus-Liebig-University, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany); Dankwort, Torben; Kienle, Lorenz [Institute for Material Science, Christian-Albrechts-University, Kaiserstrasse 2, D-24143 Kiel (Germany); Mueller, Eckhard, E-mail: Eckhard.Mueller@dlr.de [Institute for Inorganic and Analytical Chemistry, Justus-Liebig-University, Heinrich-Buff-Ring 17, D-35392 Giessen (Germany); Institute of Materials Research, German Aerospace Center (DLR), D-51170 Cologne (Germany)

2016-06-07

We report on the preparation and thermoelectric properties of the quaternary system AgPb{sub m}BiTe{sub 2+m} (Bismuth-Lead-Silver-Tellurium, BLST-m) that were nanostructured by mechanical alloying. Nanopowders of various compositions were compacted by three different methods: cold pressing/annealing, hot pressing, and short term sintering. The products are compared with respect to microstructure and sample density. The thermoelectric properties were measured: thermal conductivity in the temperature range from 300 K to 800 K and electrical conductivity and Seebeck coefficient between 100 K and 800 K. The compacting method and the composition had a substantial impact on carrier concentration and mobility as well as on the thermoelectric parameters. Room temperature Hall measurements yielded carrier concentrations in the order of 10{sup 19 }cm{sup −3}, slightly increasing with increasing content of the additive silver bismuth telluride to the lead telluride base. ZT values close to the ones of bulk samples were achieved. X-ray diffraction and transmission electron microscopy (TEM) showed macroscopically homogeneous distributions of the constituting elements inside the nanopowders ensembles, indicating a solid solution. However, high resolution transmission electron microscopy (HRTEM) revealed disorder on the nanoscale inside individual nanopowders grains.

Anomalous Pd substitution effects in the thermoelectric oxide NaCo sub 2 sub - sub x Pd sub x O sub 4

CERN Document Server

Kitawaki, R

2002-01-01

We prepared a set of polycrystalline samples of the thermoelectric oxide NaCo sub 2 sub - sub x Pd sub x O sub 4 (x = 0, 0.05, 0.1, and 0.2), and investigated the Pd substitution effects on transport phenomena. The effects are so drastic that just 5-10% Pd ions reduce the resistivity and the Seebeck coefficient to one third of the values for x = 0, and increase the magnitude of the Hall coefficient by three times. A semi-quantitative analysis has revealed that the x = 0.2 sample has much smaller effective mass and carrier concentration than the x = 0.05 sample. This is difficult to explain within a rigid-band picture, and is qualitatively consistent with a strong-correlation picture applied to the Ce-based heavy-fermion systems.

Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

Energy Technology Data Exchange (ETDEWEB)

Lopez, Luis-David Patino [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Dilhaire, Stefan [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Grauby, Stephane [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Salhi, M Amine [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Ezzahri, Younes [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Claeys, Wilfrid [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Batsale, Jean-Christophe [Laboratoire TREFLE, Esplanade des Arts et Metiers, 33405 Talence Cedex (France)

2005-05-21

An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties.

Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

International Nuclear Information System (INIS)

Lopez, Luis-David Patino; Dilhaire, Stefan; Grauby, Stephane; Salhi, M Amine; Ezzahri, Younes; Claeys, Wilfrid; Batsale, Jean-Christophe

2005-01-01

An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties

CO<sub>2sub> Problems and waste recycling. Research at the Institute of ferrous metallurgy

OpenAIRE

Gudenau, H. W.; Senk, D.; Babich, A.; Fröhling, C.; Kueon, O. S.; Wang, S.; Wieting, X.

2005-01-01

In a short introduction tests and calculations about CO<sub>2sub>-ice-blocs in the deep sea, use of CO<sub>2sub> for underground-coal-gasification and tertiary processes to increase oil-production by C02-flooding are shown. New activities are presented e.g. CO<sub>2sub>-injection into EAF combined with injection of coal, coke or directreduction-fines. After research of injection of coals, fine ores or dust into blast furnaces and other shaft furnaces ...

Electrical and thermal transport properties of layered Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xiao, Yu; Pei, Yanling; Chang, Cheng; Zhang, Xiao [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Tan, Xing [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ye, Xinxin [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Gong, Shengkai [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Lin, Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); He, Jiaqing [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

2016-07-15

Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} possesses a low thermal conductivity and high electrical conductivity at room temperature, which was considered as a potential thermoelectric material. In this work, we have investigated the electrical and thermal transport properties of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system in the temperature range from 300 K to 873 K. We found that the total thermal conductivity decreases from ~1.8 W m{sup −1} K{sup −1} to ~0.9 W m{sup −1} K{sup −1}, and the electrical conductivity decreases from ~850 S/cm to ~163 S/cm in the measured temperature range. To investigate how potential of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system, we prepared the heavily Iodine doped samples to counter-dope intrinsically high carrier concentration and improve the electrical transport properties. Interestingly, the Seebeck coefficient could be enhanced to ~+80 μV/K at 873 K, meanwhile, we found that a low thermal conductivity of ~0.7 W m{sup −1} K{sup −1} could be achieved. The intrinsically low thermal conductivity in this system is related to the low elastic properties, such as Young's modulus of 70–72 GPa, and Grüneisen parameters of 1.55–1.71. The low thermal conductivity makes Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system to be a potential thermoelectric material, the ZT value ~0.06 at 873 K was obtained, a higher performance is expected by optimizing electrical transport properties through selecting suitable dopants, modifying band structures or by further reducing thermal conductivity through nanostructuring etc. - Highlights: • The total thermal conductivity decreases from 1.8 to 0.9 Wm{sup –1}K{sup –1} at 300–873K. • The electrical conductivity decreased from 850 to 163 S/cm at 300–873K. • The Seebeck coefficients were enhanced through heavily Iodine doping. • The ZT ~0.06 at 873K suggests that Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} systems are potential thermoelectrical materials.

Magnon polarons in the spin seebeck effect

NARCIS (Netherlands)

Kikkawa, T.; Shen, K.; Flebus, B.; Duine, R.A.; Uchida, K.I.; Qiu, Z.; Bauer, G.E.W.; Saitoh, E.

2016-01-01

Sharp structures in the magnetic field-dependent spin Seebeck effect (SSE) voltages of Pt/Y3Fe5O12 at low temperatures are attributed to the magnon-phonon interaction. Experimental results are well reproduced by a Boltzmann theory that includes magnetoelastic coupling. The SSE anomalies coincide

Transverse Seebeck and Peltier effect in tilted metal-semiconductor multilayer structures; Transversaler Seebeck- und Peltier-Effekt in verkippten Metall-Halbleiter-Multilagenstrukturen

Energy Technology Data Exchange (ETDEWEB)

Reitmaier, Christina

2012-07-01

Whether in aerospace, automobile industry or in home appliances, thermoelectric effects find use in many areas of technology. This work deals with the investigation of a special form of these effects, the transversal Seebeck- and Peltier effect. Via modelling under variation of the sample parameters the cooling efficiencies, the attainable temperature differences and the Figures of merit are optimised and than suitable samples are produced according to these specifications. With these tilted metal semiconductor multilayer structures consisting of lead and bismuth telluride a transversal Peltier effect is observed. Moreover, the generation of electric power is examined via the transversal Seebeck effect. In tilted Pb-Bi2Te3 multilayers the efficiency is measured with the conversion by heat in electric power and is compared to model calculations. (orig.)

Enhanced thermoelectric performance of xMoS{sub 2}–TiS{sub 2} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ye, Yang; Wang, Yulong; Shen, YaWei [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Wang, Yifeng, E-mail: yifeng.wang@njtech.edu.cn [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Pan, Lin [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Tu, Rong [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Lu, Chunhua [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Huang, Rong [School of Information Science and Technology, East China Normal University, Shanghai 200062 (China); Koumoto, Kunihito [Toyota Physical and Chemical Research Institute, Nagakute 4801192 (Japan)

2016-05-05

A series of nanocomposite ceramics of micro-scale TiS{sub 2} containing MoS{sub 2} nanoparticles mainly embedded along grain boundaries were prepared and investigated attempting to enhance the thermoelectric performance of TiS{sub 2}. Results show that, compared with that of pristine TiS{sub 2} ceramic, the power factor of the composites was improved by virtues of enhanced Seebeck coefficient that should be brought out due to reduced carrier concentration and electron scattering or filtering at the MoS{sub 2}/matrix interfaces. Moreover, thanks to the significantly reduced thermal conductivity that originated from the intensified multi-scale phonon scattering and the decreased electronic contribution, a maximal ZT value of 0.29 at 573 K was obtained in the sample with 3 mol % MoS{sub 2}, which is 60% higher than that of pristine TiS{sub 2}. These findings promise nanocomposite as an effective approach to suppress its thermal conduction without degradation of power factor and thus to enhance the performance of TiS{sub 2}-based thermoelectrics. - Highlights: • Nanocomposites of TiS{sub 2} including nano-MoS{sub 2} were prepared by SPS. • Distribution of MoS{sub 2} mainly along the boundaries was confirmed. • Seebeck coefficient increased by reduced electron density with electron filtering. • Thermal conductivity decreased by suppressed phonon and electron transport. • A maximal ZT value of 0.29 was obtained at 573 K.

Sub-ppm analysis using a compact EDX

International Nuclear Information System (INIS)

Muraoka, Koichi; Utaka, Tadashi; Taniguchi, Kazuo

2009-01-01

As an important solution for the Soil Contamination Countermeasures Laws and China RoHS as well as EU WEEE/RoHS/ELV Directives, an EDX analyzer has been utilized as a simple and convenient instrument for promptly screening the hazardous heavy elements with high reproducibility in non-destructive manner. However, with the increasing varieties of measuring samples, the development of a high performance, more convenient and portable instrument has been expected. To meet these demands, based on the compact X-ray optical technology, using a miniature X-ray tube, a primary beam filter method and portable semiconductor detector with Peltier cooling system, we have developed a high-performance EDX Analyzer. In this study, thus, the hardware configurations and the obtained research results for sub-ppm analysis of Cd in brown rice and soil are reported. (author)

Large spin Seebeck effects in zigzag-edge silicene nanoribbons

International Nuclear Information System (INIS)

Yang, Xi-Feng; Liu, Yu-Shen; Feng, Jin-Fu; Wang, Xue-Feng

2014-01-01

Using the first-principles methods, we investigate the thermospin properties of a two-probe model based on zigzag-edge silicene nanoribbons (ZSiNRs). Compared with the odd-width ZSiNRs, the spin Seebeck coefficient of the even-width ZSiNRs is obviously enhanced at room temperature. This fact is attributed to a nearly perfect symmetry of the linear conductance gap with the different spin index with respect to the Fermi level induced by the different parity of the wave functions. More interestingly, the corresponding charge Seebeck coefficient is near zero. Therefore, when a thermal bias is presented in the even-width ZSiNRs, a nearly pure spin current is achieved. Meanwhile, the spin polarization of the current approaches infinite

Effects of Ni and carbon-coated Ni addition on the thermoelectric properties of 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} base composites

Energy Technology Data Exchange (ETDEWEB)

Yoon, Sang Min; Dharmaiah, Peyala; Femi, Olu Emmanuel; Lee, Chul Hee; Hong, Soon-Jik, E-mail: hongsj@kongju.ac.kr

2017-07-01

In this paper, we report the effect of nickel (Ni) and carbon coated nickel (C-Ni) on the thermoelectric and mechanical properties of 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} (GA) base composites. Ni and C-Ni powders were synthesized using pulse wire evaporation and mixed with 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} in a planetary ball mill. The morphology of the Ni and C-Ni powders and GA + x (x = none, Ni, or C-Ni) composites were examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermoelectric properties of the GA + x (x = none, Ni, or C-Ni) composites shows that the addition of Ni increases the carrier concentration while the presence of C-Ni reduces the carrier concentration to a level comparable to the bare sample (x = 0). Subsequently, the Seebeck coefficient of the GA + C-Ni sample increases by about 18% more than in the bare sample. The thermal conductivity of the GA + Ni and GA + C-Ni samples was considerably lower at room temperature compared to the bare sample. The mechanical properties of the GA + Ni and GA + C-Ni composite samples show a three-fold improvement compared to the bare sample. - Highlights: • Ni and carbon-coated Ni nanoparticles were incorporated into 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} (BST) matrix. • Seebeck coefficient increased by 18% for BST/carbon coated Ni composites. • BST/carbon coated Ni composite reduces the thermal conductivity (21%). • The Vickers hardness of the BST/C-Ni composite samples significantly improved.

Spark-plasma-sintering magnetic field assisted compaction of Co{sub 80}Ni{sub 20} nanowires for anisotropic ferromagnetic bulk materials

Energy Technology Data Exchange (ETDEWEB)

Ouar, Nassima; Schoenstein, Frédéric; Mercone, Silvana; Farhat, Samir; Jouini, Noureddine [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, LSPM—UPR 3407, Université Paris 13, Sorbonne-Paris-Cité, 99 Avenue J.-B. Clément, 93430 Villetaneuse (France); Villeroy, Benjamin [Institut de Chimie et des Matériaux Paris Est, CNRS, ICMPE—UMR 7182, Equipe de Chimie Métallurgique des Terres Rares, 2-8 rue Henri Dunant, 94320 Thiais Cedex (France); Leridon, Brigitte [Laboratoire de Physique et d’Étude des Matériaux, LPEM, ESPCI-ParisTech, CNRS, UPMC, 10 rue Vauquelin, F-75231 Paris Cedex 5 (France)

2013-10-28

We developed a two-step process showing the way for sintering anisotropic nanostructured bulk ferromagnetic materials. A new reactor has been optimized allowing the synthesis of several grams per batch of nanopowders via a polyol soft chemistry route. The feasibility of the scale-up has been successfully demonstrated for Co{sub 80}Ni{sub 20} nanowires and a massic yield of ∼97% was obtained. The thus obtained nanowires show an average diameter of ∼6 nm and a length of ∼270 nm. A new bottom-up strategy allowed us to compact the powder into a bulk nanostructured system. We used a spark-plasma-sintering technique under uniaxial compression and low temperature assisted by a permanent magnetic field of 1 T. A macroscopic pellet of partially aligned nanowire arrays has been easily obtained. This showed optimized coercive properties along the direction of the magnetic field applied during compaction (i.e., the nanowires' direction)

Influence of electron beam irradiation on electrical, structural, magnetic and thermal properties of Pr{sub 0.8}Sr{sub 0.2}MnO{sub 3} manganites

Energy Technology Data Exchange (ETDEWEB)

Christopher, Benedict [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Rao, Ashok, E-mail: ashokanu_rao@rediffmail.com [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Petwal, Vikash Chandra; Verma, Vijay Pal; Dwivedi, Jishnu [Industrial Accelerator Section, PSIAD, Raja Ramanna Centre for Advanced Technology, Indore 452012, M.P. (India); Lin, W.J. [Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan (China); Kuo, Y.-K., E-mail: ykkuo@mail.ndhu.edu.tw [Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan (China)

2016-12-01

In this communication, the effect of electron beam (EB) irradiation on the structural, electrical transport and thermal properties of Pr{sub 0.8}Sr{sub 0.2}MnO{sub 3} manganites has been investigated. Rietveld refinement of XRD data reveals that all samples are single phased with orthorhombic distorted structure (Pbnm). It is observed that the orthorhombic deformation increases with EB dosage. The Mn–O–Mn bond angle is found to increase with increase in EB dosage, presumably due to strain induced by these irradiations. Analysis on the measured electrical resistivity data indicates that the small polaron hopping model is operative in the high temperature region for pristine as well as EB irradiated samples. The electrical resistivity in the entire temperature region has been successfully fitted with the phenomenological percolation model which is based on phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. The Seebeck coefficient (S) of the pristine as well as the irradiated samples exhibit positive values, indicating that holes is the dominant charge carriers. The analysis of Seebeck coefficient data confirms that the small polaron hopping mechanism governs the thermoelectric transport in the high temperature region. In addition, Seebeck coefficient data also is well fitted with the phenomenological percolation model. The behavior in thermal conductivity at the transition is ascribed to the local anharmonic distortions associated with small polarons. Specific heat measurement indicates that electron beam irradiation enhances the magnetic inhomogeneity of the system.

Effect of Ca doping level on the laser-induced voltages in tilted La{sub 1-x}Ca{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.7) thin films

Energy Technology Data Exchange (ETDEWEB)

Ma, Ji; Zhang, Hui; Chen, Qingming; Liu, Xiang [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China); Theingi, Mya [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China); University of Yangon, Department of Chemistry, Yangon (Myanmar)

2014-03-15

Tilted La{sub 1-x}Ca{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.7) thin films have been grown on vicinal cut LaAlO{sub 3} (100) substrate by pulsed laser deposition. The laser-induced voltage effect was studied at room temperature with the KrF excimer laser using as the thermal source. The relationships between Ca doping level and voltage signal, response time and anisotropy Seebeck coefficient were established. The voltage signal and anisotropy Seebeck coefficient increase at first with increasing Ca doping level, reach a maximum at the same Ca content around x = 0.5, and then decrease. The respond time decreases with the Ca concentration increasing, and changes very little after x = 0.5. The figure of merit F{sub m} was also the largest at this doping level, indicating a potential good performance of the photodetector devices. The variation of intrinsic structural and transport anisotropy induced by the change of Ca concentration has been proposed to account for the different LIV effects observed in LCMO thin films. (orig.)

Influence of defects and disorder on anomalous Hall effect and spin Seebeck effect on permalloy and Heusler compounds

Energy Technology Data Exchange (ETDEWEB)

Vilanova Vidal, Enrique

2012-09-19

In this work Heusler thin films have been prepared and their transport properties have been studied. Of particularly interest is the anomalous Hall effect (AHE). The effect is a long known but still not fully understood transport effect. Most theory papers focus on the influence of one particular contribution to the AHE. Actual measured experimental data, however, often are not in accordance with idealized assumptions. This thesis discusses the data analysis for materials with low residual resistivity ratios. As prototypical materials, half metallic Heusler compounds are studied. Here, the influence of defects and disorder is apparent in a material with a complex topology of the Fermi surface. Using films with different degrees of disorder, the different scattering mechanisms can be separated. For Co{sub 2}FeSi{sub 0.6}Al{sub 0.4} and Co{sub 2}FeGa{sub 0.5}Ge{sub 0.5}, the AHE induced by B2-type disorder and temperature-dependent scattering is positive, while DO{sub 3}-type disorder and possible intrinsic contributions possess a negative sign. For these compounds, magneto-optical Kerr effects (MOKE) are investigated. First order contributions as a function of intrinsic and extrinsic parameters are qualitatively analyzed. The relation between the crystalline ordering and the second order contributions to the MOKE signal is studied. In addition, sets of the Heusler compound Co{sub 2}MnAl thin films were grown on MgO(100) and Si(100) substrates by radio frequency magnetron sputtering. Composition, magnetic and transport properties were studied systematically for samples deposited at different conditions. In particular, the anomalous Hall effect resistivity presents an extraordinarily temperature independent behavior in a moderate magnetic field range from 0 to 0.6 T. The off-diagonal transport at temperatures up to 300 C was analyzed. The data show the suitability of the material for Hall sensors working well above room temperature. Recently, the spin Seebeck effect

Improved performance of dye-sensitized solar cell with a specially tailored TiO{sub 2} compact layer prepared by RF magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Abdullah, M.H., E-mail: hanapiah801@ppinang.uitm.edu.my [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

2014-07-05

Highlights: • A novel gradient index antireflective TiO{sub 2} compact layer based DSSC was fabricated. • Higher right-shifted transmittance spectra favour the spectral response of N719 dye. • The arc-TiO{sub 2} film on ITO has decreased the charge interfacial resistance, R{sub 1}. • The arc-TiO{sub 2} film prevents electrons recombination at ITO and nc-TiO{sub 2} interfaces. • Almost 42% increment in the overall efficiency compared to the bare ITO cell. - Abstract: We demonstrate that a graded index TiO{sub 2} antireflective compact layer (arc-TiO{sub 2}) employed by RF sputtering can modulate the optical transmittance and reduce the electron recombination in dye-sensitized solar cell (DSSC). The spectral response of the DSSC is improved, due to higher and red-shifted transmittance spectra in a specific region that favours the sensitization effect of the dye. The effects of arc-TiO{sub 2} prepared at various RF sputtering powers to the performances of DSSC were investigated by means of the incident photo to current efficiency (IPCE), open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS). The slow decay of the photo-voltage attributed to the desirable merits of the arc-TiO{sub 2} compact layer has been evidenced by the OCVD measurement. Meanwhile, the improvement of adhesion between an arc-TiO{sub 2} film and porous-TiO{sub 2} has decreased the interfacial-charge resistance, R{sub 1} in the EIS measurement. This lower R{sub 1} then facilitates the charge-transfer process of the electron in the DSSC. At 100 W of RF power, these blended effects improved the overall conversion efficiency of the DSSC by an increase of 42% compared to the cell without the compact layer.

Easily controlled dye doped phosphorescent OLEDs with evaporation rate in single furnace

Energy Technology Data Exchange (ETDEWEB)

Mahmoudi, Malek; Janghouri, Mohammad; Mohajerani, Ezeddin, E-mail: e-mohajerani@sbu.ac.ir

2015-04-15

Electrical and optical characteristic, surface morphology and energy transfer of Ir(ppy){sub 3}:PtTPP were studied as a function of thermal evaporation rate. We have investigated the effect of various evaporation rates for mixture of dyes using single furnace method. When the deposition rate increased from 0.5 to 5 Ǻ/s, the luminescence efficiency, current density and energy transfer of OLED increased. AFM measurements showed that the surface roughness of the Ir(ppy){sub 3}:PtTPP films decreased with increasing deposition rates. These blends show excellent red emitting guest–host system with easier deposition rate control. - Highlights: • Thermal evaporation rate is used to control the doping by using single furnace. • The advantages of using single furnace are discussed. • It is shown that the evaporation rate also affects the surface roughness.

Minimization of Blast furnace Fuel Rate by Optimizing Burden and Gas Distribution

Energy Technology Data Exchange (ETDEWEB)

Dr. Chenn Zhou

2012-08-15

The goal of the research is to improve the competitive edge of steel mills by using the advanced CFD technology to optimize the gas and burden distributions inside a blast furnace for achieving the best gas utilization. A state-of-the-art 3-D CFD model has been developed for simulating the gas distribution inside a blast furnace at given burden conditions, burden distribution and blast parameters. The comprehensive 3-D CFD model has been validated by plant measurement data from an actual blast furnace. Validation of the sub-models is also achieved. The user friendly software package named Blast Furnace Shaft Simulator (BFSS) has been developed to simulate the blast furnace shaft process. The research has significant benefits to the steel industry with high productivity, low energy consumption, and improved environment.

Thermoelectric power in ionic and electronic mixed conductors

Energy Technology Data Exchange (ETDEWEB)

Kamata, Masahiro; Jin-nouchi, Kenji; Esaka, Takao [Tottori Univ. (Japan). Faculty of Engineering

1996-08-01

In order to study the thermoelectric property of the oxide ionic and electronic mixed conductor of 10 mol% CaO-doped CeO{sub 2} (CDC), a new type of thermocell was prepared, in which platinum electrodes were embedded in the tube-type sample to diminish the large temperature gradient over the electrodes due to the local heat radiation from heating furnace. Using this thermocell, reproducible data were obtained. The thermoelectric power measured in CDC under various oxygen atmospheres (Po{sub 2}) from 1.0 to about 10{sup -15} atm showed that the sign of Seebeck coefficients changed from minus to plus. This variation of Seebeck coefficients vs. Po{sub 2} was well interpreted by considering that (1) the thermoelectric power could be a driving force to make actual and electrochemical oxygen transfer in the mixed conductor and (2) the electrode processes had limiting rates due to slow oxygen diffusion (or oxygen gas exhaustion at the cathode and evolution at the anode). (author)

FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL; SEMIANNUAL

International Nuclear Information System (INIS)

Gary M. Blythe

2002-01-01

This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period October 1, 2001 through March 31, 2002. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO(sub X) selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. This is the fifth reporting period for the subject Cooperative Agreement. During the previous (fourth) period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant) and a byproduct magnesium hydroxide slurry (at both Gavin and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO(sub 3) formed across the SCR system installed on the unit for NO(sub X) control than at removing SO(sub 3) formed in the furnace. The SO(sub 3) removal results were presented in the

Development of ceramics based fuel, Phase I, Kinetics of UO{sub 2} sintering by vibration compacting of UO{sub 2} powder (Introductory report); Razvoj goriva na bazi keramike, I faza, Kinetika sinterovanja UO{sub 2} vibraciono kompaktiranje praha UO{sub 2} (Uvodni izvestaj)

Energy Technology Data Exchange (ETDEWEB)

Ristic, M M [Institute of Nuclear Sciences Vinca, Laboratorija za reaktorske materijale, Beograd (Serbia and Montenegro)

1962-10-15

After completing the Phase I of the task related to development of ceramics nuclear fuel the following reports are presented: Kinetics of UO{sub 2} sintering; Vibrational compacting and sintering of UO{sub 2}; Characterisation of of UO{sub 2} powder by DDK and TGA methods; Separation of UO{sub 2} powder.

Furnace for the continuous sintering of pellets of ceramic nuclear fuel material

International Nuclear Information System (INIS)

Heyraud, J.

1977-01-01

The furnace comprises a hearth for the longitudinal displacement of pellet containers, means for injecting gas at both ends of the furnace, for sucking gas between preheating and sintering zones and for condensing the binder, means for displacing the containers from an introduction lock-chamber to an extraction lock-chamber, a conveyor belt which passes through a glove box and provides a leak-tight connection between the lock-chambers. A station for loading containers with pellet sub-containers prior to sintering and a station for unloading the pellet sub-containers after sintering are juxtaposed within the glove box. 3 claims, 1 drawing figure

A pilot plant study for CO{sub 2} capture by aqueous ammonia applied to blast furnace gas in iron and steel making process

Energy Technology Data Exchange (ETDEWEB)

Young Kim, J.; Han, K.; Dong Chun, H. [CO2 Project, Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of)

2009-07-01

This presentation reported on a study in which carbon dioxide (CO{sub 2}) was captured from a demonstration iron and steel plant using low concentration aqueous ammonia as the absorbent chemical. The pilot plant was designed to process 50 Nm{sup 3}/h of blast furnace gas (BFG). The feed gas contained more than 20 per cent CO{sub 2} at 35 to 60 degrees C. Test runs revealed that the absorption efficiency of CO{sub 2} exceeded 80 per cent with a CO{sub 2} purity of more than 90 per cent in the product stream. The process parameters are currently being studied along with the various salts needed to prevent salt precipitation. It was determined that the use of waste heat recovery technology in the iron and steel-making process can render ammonia-based CO{sub 2} capture technology more economically feasible for the reduction of CO{sub 2}.

Effects of sintering and paste-baking conditions on PTCR characteristic of (Ba,Sr)TiO{sub 3} vacuum-sintered compact added with TiO{sub 2}(Ti) powder; TiO{sub 2}(ti) fun tenka (Ba,Sr)TiO{sub 3} shinku shoketsutai no PTCR tokusei ni oyobosu shoketsu oyobi paste yakitsuke joken no eikyo

Energy Technology Data Exchange (ETDEWEB)

Kim, J.; Hayashi, K. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

1999-04-15

The effects of sintering temperature (T{sub s}; 1,573 {approx} 1,748K) and time (t{sub s}; 0.6 {approx} 14.4ks) and paste-baking-temperature or heating temperature (T{sub b} or T{sub h}; 673 {approx} 1,273K; t{sub b} is 0.3ks) on PTCR characteristic were investigated for (Ba, Sr)TiO{sub 3} vacuum-sintered compact added with 3.9mass% TiO{sub 2}(Ti) powder of 12.5mass% TiO{sub 2}. The results obtained were as follows; (1) PTCR characteristic developed at all T{sub s} (t{sub s}=3.6ks, T{sub b}=853K). The electrical resistivity at room temperature ({rho}{sub rt}) showed a minimum value of 1.8 times 10{sup 2}ohmcenter dotcm and the {rho}{sub max}/{rho}{sub rt} showed a maximum value of about 10{sup 6} at 1,723K. (2)For all t{sub s} (T{sub s}=1,623K, T{sub b}=853K), PTCR characteristic developed. The {rho}{sub rt} showed a minimum value of 2.6 times 10{sup 3}ohmcenter dotcm at 7.2ks. (3) At T{sub b} above 823K (T{sub s}=1,623K, t{sub s}=3.6ks), PTCR characteristic developed. The {rho}{sub rt} showed a minimum value of 1.0 times 10{sup 3}ohmcenter dotcm. (4)The {rho}-T curve of (Ba, Sr)TiO{sub 3}+TiO{sub 2}(Ti) vacuum-sintered compact was affected more largely by T{sub s}, t{sub s} and T{sub b} than that of (Ba, Sr)TiO{sub 3} air-sintered compact. This was considered to be mainly due to the porous and fine gained microstructure in the former compact. (author)

Reduction of NOx emission in tangential fired - furnace by changing the, mode of operation

International Nuclear Information System (INIS)

Chudnovsky, B.; Talanker, A.; Levin, L.; Kahana, S

1998-01-01

The present work analyses tile results of tests on 575 MW units with tangential firing furnace arrangement in sub-stoichiometric combustion. Tangential firing provides good conditions for implementing sub-stoichiometric combustion owing to the delivery scheme of pulverized coal and air. The furnace was tested in several different modes of operation (Over Fire Air, Bunkers Out Of Service, Excess air, Tilt etc.) to achieve low cost NOx reduction. Actual performance data are presented based on experiments made on lEC's boiler in M.D. 'B' power station

Furnace for distillation of shales, etc

Energy Technology Data Exchange (ETDEWEB)

Germain-Clergault, M

1863-07-09

Practical experience and continuous operation of 55 retorts for 5 years of the system of vertical retorts patented in 1857 (French Patent 18,422) has shown the advantages resulting from this furnace which gives over a mean yield of 5% of Auton shale, which is /sup 1///sub 2/% more than the old systems with a fuel economy varying from 15 to 20%.

Model calculation of the characteristic mass for convective and diffusive vapor transport in graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Bencs, László, E-mail: bencs.laszlo@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Laczai, Nikoletta [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Ajtony, Zsolt [Institute of Food Science, University of West Hungary, H-9200 Mosonmagyaróvár, Lucsony utca 15–17 (Hungary)

2015-07-01

A combination of former convective–diffusive vapor-transport models is described to extend the calculation scheme for sensitivity (characteristic mass — m{sub 0}) in graphite furnace atomic absorption spectrometry (GFAAS). This approach encompasses the influence of forced convection of the internal furnace gas (mini-flow) combined with concentration diffusion of the analyte atoms on the residence time in a spatially isothermal furnace, i.e., the standard design of the transversely heated graphite atomizer (THGA). A couple of relationships for the diffusional and convectional residence times were studied and compared, including in factors accounting for the effects of the sample/platform dimension and the dosing hole. These model approaches were subsequently applied for the particular cases of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sn, V and Zn analytes. For the verification of the accuracy of the calculations, the experimental m{sub 0} values were determined with the application of a standard THGA furnace, operating either under stopped, or mini-flow (50 cm{sup 3} min{sup −1}) of the internal sheath gas during atomization. The theoretical and experimental ratios of m{sub 0}(mini-flow)-to-m{sub 0}(stop-flow) were closely similar for each study analyte. Likewise, the calculated m{sub 0} data gave a fairly good agreement with the corresponding experimental m{sub 0} values for stopped and mini-flow conditions, i.e., it ranged between 0.62 and 1.8 with an average of 1.05 ± 0.27. This indicates the usability of the current model calculations for checking the operation of a given GFAAS instrument and the applied methodology. - Highlights: • A calculation scheme for convective–diffusive vapor loss in GFAAS is described. • Residence time (τ) formulas were compared for sensitivity (m{sub 0}) in a THGA furnace. • Effects of the sample/platform dimension and dosing hole on τ were assessed. • Theoretical m{sub 0} of 18 analytes were

Chemical, physical, structural and morphological characterization of the electric arc furnace dust

Energy Technology Data Exchange (ETDEWEB)

Machado, Janaina G.M.S. [Laboratorio de Siderurgia/LASID, Universidade Federal do Rio Grande do Sul, UFRGS/PPGEM Centro de Tecnologia, AV. Bento Goncalves 9500 CEP, 91501-970 Caixa postal 15021, Porto Alegre, RS (Brazil)]. E-mail: jana@ct.ufrgs.br; Brehm, Feliciane Andrade [Nucleo de Caracterizacao de Materiais/NucMat, Universidade do Vale do Rio dos Sinos, UNISINOS, Sao Leopoldo, RS (Brazil); Moraes, Carlos Alberto Mendes [Nucleo de Caracterizacao de Materiais/NucMat, Universidade do Vale do Rio dos Sinos, UNISINOS, Sao Leopoldo, RS (Brazil); Santos, Carlos Alberto dos [Nucleo de Educacao a Distancia, Universidade Estadual do Rio Grande do Sul, UERGS, Porto Alegre, RS (Brazil); Vilela, Antonio Cezar Faria [Laboratorio de Siderurgia/LASID, Universidade Federal do Rio Grande do Sul, UFRGS/PPGEM Centro de Tecnologia, AV. Bento Goncalves 9500 CEP, 91501-970 Caixa postal 15021, Porto Alegre, RS (Brazil); Cunha, Joao Batista Marimon da [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, UFRGS, Campus do Vale, Porto Alegre, RS (Brazil)

2006-08-25

Electric arc furnace dust (EAFD) is a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Important elements to the industry such as, Fe and Zn are the main ones in EAFD. Due to their presence, it becomes very important to know how these elements are combined before studying new technologies for its processing. The aim of this work was to carry out a chemical, physical, structural and morphological characterization of the EAFD. The investigation was carried out by using granulometry analysis, chemical analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy via SEM (EDS), X-ray mapping analysis via SEM, X-ray diffraction (XRD) and Moessbauer spectroscopy. By XRD the following phases were detected: ZnFe{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, MgFe{sub 2}O{sub 4}, FeCr{sub 2}O {sub 4}, Ca{sub 0.15}Fe{sub 2.85}O{sub 4}, MgO, Mn{sub 3}O{sub 4}, SiO{sub 2} and ZnO. On the other hand, the phases detected by Moessbauer spectroscopy were: ZnFe{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Ca{sub 0.15}Fe{sub 2.85}O{sub 4} and FeCr{sub 2}O{sub 4}. Magnesium ferrite (MgFe{sub 2}O{sub 4}), observed in the XRD pattern as overlapped peaks, was not identified in the Moessbauer spectroscopy analysis.

Furnaces. The manufacturer turns to the engineering office; Les fours. Le constructeur devient bureau d`ingenierie

Energy Technology Data Exchange (ETDEWEB)

Nivoche, C. [Selas SA, 92 - Gennevilliers (France)

1997-12-31

This paper describes the actions carried out by the Selas company involved in the manufacturing of industrial furnaces in order to respect the environmental regulations of the French 2910 by-law: particularity of industrial furnaces, activities of the Selas company (surface cleaning process for iron and stainless steel sheets, quenching of glass panes), reduction of dust, SO{sub x}, NO{sub x} and organic compound emissions from combustion systems and burners. (J.S.)

Kinetics of the reaction of iron blast furnace slag/hydrated lime sorbents with SO{sub 2} at low temperatures: effects of the presence of CO{sub 2}, O{sub 2}, and NOx

Energy Technology Data Exchange (ETDEWEB)

Liu, C.F.; Shih, S.M. [Industrial Technological Research Institute, Hsinchu (Taiwan)

2009-09-15

The effects of the presence of CO{sub 2}, O{sub 2}, and NOx in the flue gas on the kinetics of the sulfation of blast furnace slag/hydrated lime sorbents at low temperatures were studied using a differential fixed-bed reactor. When O{sub 2} and NOx were not present simultaneously, the reaction kinetics was about the same as that under the gas mixtures containing SO{sub 2}, H{sub 2}O, and N{sub 2} only, being affected mainly by the relative humidity. The sulfation of sorbents can be described by the surface coverage model and the model equations derived for the latter case. When both O{sub 2} and NOx, were present, the sulfation of sorbents was greatly enhanced, forming a great amount of sulfate in addition to sulfite. The surface coverage model is still valid in this case, but the model equations obtained show a more marked effect of relative humidity and negligible effects of SO{sub 2} concentration and temperature on the reaction. The effect of sorbent composition on the reaction kinetics was entirely represented by the effects of the initial specific surface area (S{sub g0}) and the Ca molar content (M{sup -1}) of sorbent. The initial conversion rate of sorbent increased linearly with increasing S{sub g0}, and the ultimate conversion increased linearly with increasing S{sub g0}M{sup -1}. The model equations obtained in this work are applicable to describe the kinetics of the sulfation of the sorbents in the low-temperature dry and semidry fine gas desulfurization processes either with an upstream NOx, removal unit or without.111

Effect of mineral admixtures on kinetic property and compressive strength of self Compacting Concrete

Science.gov (United States)

Jagalur Mahalingasharma, Srishaila; Prakash, Parasivamurthy; Vishwanath, K. N.; Jawali, Veena

2017-06-01

This paper presents experimental investigations made on the influence of chemical, physical, morphological and mineralogical properties of mineral admixtures such as fly ash, ground granulate blast furnace slag, metakaoline and micro silica used as a replacement of cement in self compacting concrete on workability and compressive strength. Nineteen concrete mixes were cast by replacing with cement by fly ash or ground granulated blast furnace slag as binary blend at 30%, 40%, 50% and with addition of micro silica and metakaoline at 10% as a ternary blend with fly ash, ground granulated blast furnace slag and obtained results were compare with control mix. Water powder ratio 0.3 and super plasticizer dosage 1% of cementitious material was kept constant for all the mixes. The self compacting concrete tested for slump flow, V-funnel, L-Box, J-Ring, T50, and compressive strength on concrete cube were determined at age of 3, 7, 28, 56, 90 days.

Anomalous temperature dependence of the Seebeck coefficient for the substitutionally-disordered hopping conductors

International Nuclear Information System (INIS)

Raffaelle, R.P.; Parris, P.E.; Anderson, H.U.; Sparlin, D.M.

1991-01-01

Thermoelectric power measurements are presented for the (La,Sr)(Cr,Mn)O 3 series. The nonlinear temperature dependence of the Seebeck coefficient is analyzed in terms of a random distribution of energetically equivalent hopping sites. The limitations of Heikes' formula, which has been traditionally used to calculate small polaron carrier densities in these systems, are discussed. Recent theoretical developments in the interpretation of Seebeck measurements in substitutionally-disordered high-temperature hopping conductors are reviewed

Effects of MeV Si ions bombardment on the thermoelectric generator from SiO{sub 2}/SiO{sub 2} + Cu and SiO{sub 2}/SiO{sub 2} + Au nanolayered multilayer films

Energy Technology Data Exchange (ETDEWEB)

Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Chacha, J., E-mail: chacha_john79@hotmail.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Smith, C., E-mail: cydale@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States); Pugh, M., E-mail: marcuspughp@yahoo.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Colon, T. [Department of Mechanical Engineering, Alabama A and M University, Normal, AL (United States); Heidary, K., E-mail: kaveh.heidary@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Johnson, R.B., E-mail: barry@w4wb.com [Department of Physics, Alabama A and M University, Normal, AL (United States); Ila, D., E-mail: ila@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States)

2011-12-15

The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO{sub 2}/SiO{sub 2} + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO{sub 2}/SiO{sub 2} + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO{sub 2}, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

A compact D-band monolithic APDP-based sub-harmonic mixer

Science.gov (United States)

Zhang, Shengzhou; Sun, Lingling; Wang, Xiang; Wen, Jincai; Liu, Jun

2017-11-01

The paper presents a compact D-band monolithic sub-harmonic mixer (SHM) with 3 μm planar hyperabrupt schottky-varactor diodes offered by 70 nm GaAs mHEMT technology. According to empirical equivalent-circuit models, a wide-band large signal equivalent circuit model of the diode is proposed. Based on the extracted model, the mixer is implemented and optimized with a shunt-mounted anti-parallel diode pair (APDP) to fulfill the sub-harmonic mixing mechanism. Furthermore, a modified asymmetric three-transmission-line coupler is devised to achieve high-level coupling and minimize the chip size. The measured results show that the conversion gain varies between -13.9 dB and -17.5 dB from 110 GHz to 145 GHz, with a local oscillator (LO) power level of 14 dBm and an intermediate frequency (IF) of 1 GHz. The total chip size including probe GSG pads is 0.57 × 0.68mm2. In conclusion, the mixer exhibits outstanding figure-of-merits.

EAF Slag Aggregate in Roller-Compacted Concrete Pavement: Effects of Delay in Compaction

Directory of Open Access Journals (Sweden)

My Ngoc-Tra Lam

2018-04-01

Full Text Available This study investigates the effect of delay in compaction on the optimum moisture content and the mechanical propertie s (i.e., compressive strength, ultrasonic pulse velocity, splitting tensile strength, and modulus of elasticity of roller-compacted concrete pavement (RCCP made of electric arc furnace (EAF slag aggregate. EAF slag with size in the range of 4.75–19 mm was used to replace natural coarse aggregate in RCCP mixtures. A new mixing method was proposed for RCCP using EAF slag aggregate. The optimum moisture content of RCCP mixtures in this study was determined by a soil compaction method. The Proctor test assessed the optimum moisture content of mixtures at various time after mixing completion (i.e., 0, 15, 30, 60, and 90 min. Then, the effect of delay in compaction on the mechanical properties of RCCP mixtures at 28 days of age containing EAF slag aggregate was studied. The results presented that the negative effect on water content in the mixture caused by the higher water absorption characteristic of EAF slag was mitigated by the new mixing method. The optimum water content and maximum dry density of RCCP experience almost no effect from the delay in compaction. The compressive strength and splitting tensile strength of RCCP using EAF slag aggregate fulfilled the strength requirements for pavement with 90 min of delay in compaction.

Thermoelastic enhancement of the magnonic spin Seebeck effect in thin films and bulk samples

Science.gov (United States)

Chotorlishvili, L.; Wang, X.-G.; Toklikishvili, Z.; Berakdar, J.

2018-04-01

A nonuniform temperature profile may generate a pure spin current in magnetic films, as observed, for instance, in the spin Seebeck effect. In addition, thermally induced elastic deformations may set in that could affect the spin current. A self-consistent theory of the magnonic spin Seebeck effect including thermally activated magnetoelastic effects is presented, and analytical expressions for the thermally activated deformation tensor and dispersion relations for coupled magnetoelastic modes are obtained. We derive analytical results for bulk (three-dimensional) systems and thin magnetic (two-dimensional) films. We observe that the displacement vector and the deformation tensor in bulk systems decay asymptotically as u ˜1 /R2 and ɛ ˜1 /R3 , respectively, while the decays in thin magnetic films proceed slower, following u ˜1 /R and ɛ ˜1 /R2 . The dispersion relations evidence a strong anisotropy in the magnetic excitations. We observe that a thermoelastic steady-state deformation may lead to both an enchantment and a reduction of the gap in the magnonic spectrum. The reduction of the gap increases the number of magnons contributing to the spin Seebeck effect and offers new possibilities for the thermoelastic control of the spin Seebeck effect.

Temperature dependence of the domain wall magneto-Seebeck effect: avoiding artifacts of lead contributions

Science.gov (United States)

Fernández Scarioni, Alexander; Krzysteczko, Patryk; Sievers, Sibylle; Hu, Xiukun; Schumacher, Hans W.

2018-06-01

We study the resistive and thermopower signatures of a single domain wall in a magnetic nanowire in the temperature range from 4 K to 204 K. The results are compared to the anisotropic magnetoresistance (AMR) and anisotropic magneto-Seebeck (AMS) data of the whole permalloy nanowire. The AMS ratio of the nanowire reveals a sign change at a temperature of 98 K, while the AMR ratio is positive over the complete temperature range. This behavior is also observed for the domain wall, allowing an attribution of the measured signatures to the domain wall magneto-Seebeck and domain wall magnetoresistive contributions. However, the observed zero crossing of the AMS ratio, in both types of measurements is not expected for permalloy, since the Mott formula predicts a temperature dependency of the AMS identical to the AMR. We discuss the origin of this behavior and can attribute it to the contributions of the lead and the protective platinum layer used in our devices. A correction scheme is presented and applied. Such contributions could also play a role in the analysis of magneto-Seebeck effects in other nanoscale devices, such as the tunnel magneto-Seebeck effect of magnetic tunnel junctions.

Electronic transport properties of hot-pressed B/sub 6/Si

International Nuclear Information System (INIS)

Wood, C.; Emin, D.; Feigelson, R.S.; Mackinnon, I.D.R.

1987-01-01

Measurements of the electrical conductivity, Seebeck coefficient and Hall mobility from --300 K to --1300 K have been carried out on multiphase hotpressed samples of the nominal composition B/sub 6/Si. In all samples the conductivity and the p-type Seebeck coefficient both increase smoothly with increasing temperature. By themselves, these facts suggest small-polaronic hopping between inequivalent sites. The measured Hall mobilities are always low, but vary in sign. A possible explanation is offered for this anomalous behavior

How to realize a spin-dependent Seebeck diode effect in metallic zigzag γ-graphyne nanoribbons?

Science.gov (United States)

Wu, Dan-Dan; Liu, Qing-Bo; Fu, Hua-Hua; Wu, Ruqian

2017-11-30

The spin-dependent Seebeck effect (SDSE) is one of the core topics of spin caloritronics. In the traditional device designs of spin-dependent Seebeck rectifiers and diodes, finite spin-dependent band gaps of materials are required to realize the on-off characteristic in thermal spin currents, and nearly zero charge current should be achieved to reduce energy dissipation. Here, we propose that two ferromagnetic zigzag γ-graphyne nanoribbons (ZγGNRs) without any spin-dependent band gaps around the Fermi level can not only exhibit the SDSE, but also display rectifier and diode effects in thermal spin currents characterized by threshold temperatures, which originates from the compensation effect occurring in spin-dependent transmissions but not from the spin-splitting band gaps in materials. The metallic characteristics of ZγGNRs bring about an advantage that the gate voltage is an effective route to adjust the symmetry of spin-splitting bands to obtain pure thermal spin currents. The results provide a new mechanism to realize spin-Seebeck rectifier and diode effects in 2D materials and expand material candidates towards spin-Seebeck device applications.

Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z ≳ 2: high velocity dispersions in progenitors of compact quiescent galaxies

Energy Technology Data Exchange (ETDEWEB)

Barro, Guillermo; Koo, David C.; Faber, Sandra M.; Guo, Yicheng; Toloba, Elisa; Fang, Jerome J. [University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Trump, Jonathan R. [Pennsylvania State University, University Park, State College, PA 16802 (United States); Dekel, Avishai [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Kassin, Susan A.; Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kocevski, Dale D. [University of Kentucky, Lexington, KY 40506 (United States); Van der Wel, Arjen [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Pérez-González, Pablo G. [Universidad Complutense de Madrid, Avda. de Sneca, 2 Ciudad Universitaria, E-28040 Madrid (Spain); Pacifici, Camilla [Yonsei University Observatory, Yonsei University 50, Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Simons, Raymond [Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2683 (United States); Campbell, Randy D.; Goodrich, Bob; Kassis, Marc [W. M. Keck Observatory, California Association for Research in Astronomy, 65-1120 Mamalahoa Highway, Kamuela, HI 96743 (United States); Ceverino, Daniel [Universidad Autonoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid (Spain); Finkelstein, Steven L. [The University of Texas at Austin, Austin, TX 78712 (United States); and others

2014-11-10

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ≤ z ≤ 2.5 with star formation rates of SFR ∼ 100 M {sub ☉} yr{sup –1} and masses of log(M/M {sub ☉}) ∼10.8. Their high integrated gas velocity dispersions of σ{sub int} =230{sub −30}{sup +40} km s{sup –1}, as measured from emission lines of Hα and [O III], and the resultant M {sub *}-σ{sub int} relation and M {sub *}-M {sub dyn} all match well to those of compact quiescent galaxies at z ∼ 2, as measured from stellar absorption lines. Since log(M {sub *}/M {sub dyn}) =–0.06 ± 0.2 dex, these compact SFGs appear to be dynamically relaxed and evolved, i.e., depleted in gas and dark matter (<13{sub −13}{sup +17}%), and present larger σ{sub int} than their non-compact SFG counterparts at the same epoch. Without infusion of external gas, depletion timescales are short, less than ∼300 Myr. This discovery adds another link to our new dynamical chain of evidence that compact SFGs at z ≳ 2 are already losing gas to become the immediate progenitors of compact quiescent galaxies by z ∼ 2.

High spin-filter efficiency and Seebeck effect through spin-crossover iron–benzene complex

Energy Technology Data Exchange (ETDEWEB)

Yan, Qiang; Zhou, Liping, E-mail: zhoulp@suda.edu.cn; Cheng, Jue-Fei; Wen, Zhongqian; Han, Qin; Wang, Xue-Feng [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China)

2016-04-21

Electronic structures and coherent quantum transport properties are explored for spin-crossover molecule iron-benzene Fe(Bz){sub 2} using density functional theory combined with non-equilibrium Green’s function. High- and low-spin states are investigated for two different lead-molecule junctions. It is found that the asymmetrical T-shaped contact junction in the high-spin state behaves as an efficient spin filter while it has a smaller conductivity than that in the low-spin state. Large spin Seebeck effect is also observed in asymmetrical T-shaped junction. Spin-polarized properties are absent in the symmetrical H-shaped junction. These findings strongly suggest that both the electronic and contact configurations play significant roles in molecular devices and metal-benzene complexes are promising materials for spintronics and thermo-spintronics.

Effects of Yttrium and Iron co-doping on the high temperature thermoelectric properties of Ca{sub 3}Co{sub 4}O{sub 9+δ}

Energy Technology Data Exchange (ETDEWEB)

Wu, NingYu, E-mail: niwu@dtu.dk; Van Nong, Ngo; Pryds, Nini; Linderoth, Søren

2015-07-25

Highlights: • The Fe and Fe/Y doping at the Co- and Ca-sites of Ca{sub 3}Co{sub 4}O{sub 9+δ} were investigated. • The rising ρ by Y doping can be mitigated by the coupled Fe doping. • The increased Seebeck coefficient by Y doping can be maintained in co-doped system. • The co-doped system leads to an improvement of the thermoelectric performance. • The co-doped system may preserve the merits from each component doping. - Abstract: A series of Y and Fe co-doped Ca{sub 3−x}Y{sub x}Co{sub 4−y}Fe{sub y}O{sub 9+δ} (0 ⩽ x ⩽ 0.3, 0 ⩽ y ⩽ 0.1) samples synthesized by auto-combustion reaction and followed by a spark plasma sintering (SPS) processing with the effects of Fe and Y doping on the high temperature (RT to 800 °C) thermoelectric properties were systematically investigated. For the Fe-doped system (x = 0, y ⩽ 0.1), the electrical resistivity (ρ) decreased over the whole measured temperature range, while the Seebeck coefficient (S) remained almost the same. For the co-doped system, at any fixed Fe doping content, both ρ and S tended to increase with increasing Y dopants, however, the effect is more substantial on ρ than on S, particularly in the low temperature regime. In contrast to ρ and S, the in-plane thermal conductivity (κ) is only slightly influenced by Y and Fe substitutions. Among all the investigated samples, the co-doped sample with x = 0.1 and y = 0.03 showed a decrease of ρ, enhanced power factor over the measured temperature range, and improved ZT at 800 °C as compared to un-doped Ca{sub 3}Co{sub 4}O{sub 9+δ}.

Enhanced thermoelectric properties of PEDOT/PSS/Te composite films treated with H{sub 2}SO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Song, Haijun; Cai, Kefeng, E-mail: kfcai@tongji.edu.cn [Tongji University, Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering (China); Shen, Shirley [CSIRO Manufacturing (Australia)

2016-12-15

Firstly, tellurium (Te) nanorods with a high Seebeck coefficient have been integrated into a conducting polymer PEDOT/PSS to form PEDOT/PSS/Te composite films. The Seebeck coefficient of the PEDOT/PSS/Te (90 wt.%) composite films is ~191 μV/K, which is about 13 times greater than that of pristine PEDOT/PSS. Then, H{sub 2}SO{sub 4} treatment has been used to further tune the thermoelectric properties of the composite films by adjusting the doping level and increasing the carrier concentration. After the acid treatment, the electrical conductivity of the composite films has increased from 0.22 to 1613 S/cm due to the removal of insulating PSS and the structural rearrangement of PEDOT. An optimized power factor of 42.1 μW/mK{sup 2} has been obtained at room temperature for a PEDOT/PSS/Te (80 wt.%) sample, which is about ten times larger than that of the untreated PEDOT/PSS/Te composite film.

Heat treatment furnace

Science.gov (United States)

Seals, Roland D; Parrott, Jeffrey G; DeMint, Paul D; Finney, Kevin R; Blue, Charles T

2014-10-21

A furnace heats through both infrared radiation and convective air utilizing an infrared/purge gas design that enables improved temperature control to enable more uniform treatment of workpieces. The furnace utilizes lamps, the electrical end connections of which are located in an enclosure outside the furnace chamber, with the lamps extending into the furnace chamber through openings in the wall of the chamber. The enclosure is purged with gas, which gas flows from the enclosure into the furnace chamber via the openings in the wall of the chamber so that the gas flows above and around the lamps and is heated to form a convective mechanism in heating parts.

Prediction of seebeck coefficient for compounds without restriction to fixed stoichiometry: A machine learning approach.

Science.gov (United States)

Furmanchuk, Al'ona; Saal, James E; Doak, Jeff W; Olson, Gregory B; Choudhary, Alok; Agrawal, Ankit

2018-02-05

The regression model-based tool is developed for predicting the Seebeck coefficient of crystalline materials in the temperature range from 300 K to 1000 K. The tool accounts for the single crystal versus polycrystalline nature of the compound, the production method, and properties of the constituent elements in the chemical formula. We introduce new descriptive features of crystalline materials relevant for the prediction the Seebeck coefficient. To address off-stoichiometry in materials, the predictive tool is trained on a mix of stoichiometric and nonstoichiometric materials. The tool is implemented into a web application (http://info.eecs.northwestern.edu/SeebeckCoefficientPredictor) to assist field scientists in the discovery of novel thermoelectric materials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Numerical study on NO formation in a pulverized coal-fired furnace using oxy-fuel combustion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Aiyue; Chen, Yuan; Sheng, Changdong [Southeast Univ., Nanjing (China). School of Energy and Environment

2013-07-01

Computational fluid dynamics (CFD) approach was employed to numerically investigate NO formation in a 600 MW wall-fired pulverized coal-fired furnace retrofitted for oxy-coal combustion, aimed at the impacts of flue gas recycle ratio, O{sub 2} staging and recycled NO with the recycled flue gas (RFG) on NO formation and emission. An in-house CFD research code for conventional air combustion was developed and extended to simulate O{sub 2}/RFG combustion with specific considerations of the change of gas properties and its impact on coal particle combustion processes. The extended De Soete mechanisms including NO reburning mechanism were applied to describe transformations of fuel nitrogen. It was shown that CFD simulation represented the significant reduction of NO formation during O{sub 2}/RFG combustion compared to that during air combustion. The in-burner and particularly the in-furnace O{sub 2} staging were confirmed still to play very important roles in NO formation control. Changing the recycle ratio had significant impact on the combustion performance and consequently on NO formation and emission. With the combustion performance ensured, decreasing the flue gas recycle ratio or increasing the inlet O{sub 2} concentration of combustion gas led to reduction of NO formation and emission. Although NO formation and emission was found to increase with increasing the inlet NO concentration of combustion gas, CFD simulation indicated that {proportional_to}74% of the inlet NO was reduced in the furnace, consistent with the experimental data reported in the literature. This demonstrated the significant contribution of reburning mechanism to the reduction of the recycled NO in the furnace.

On the crystal structure and thermoelectric properties of thin Si{sub 1–x}Mn{sub x} films

Energy Technology Data Exchange (ETDEWEB)

Erofeeva, I. V., E-mail: irfeya@mail.ru; Dorokhin, M. V.; Lesnikov, V. P.; Zdoroveishchev, A. V.; Kudrin, A. V.; Pavlov, D. A.; Usov, U. V. [Lobachevsky State University of Nizhny Novgorod, Research Institute for Physics and Technology (Russian Federation)

2016-11-15

Thin (25 nm) Si{sub 1–x}Mn{sub x}/Si(100) films are fabricated by pulsed laser deposition. According to high-resolution transmission electron microscopy data, the films have a nanotextured crystalline structure and are chemically homogeneous. The temperature dependences of the resistivity and thermopower are measured in the range of 300–500 K, and the temperature dependences of the Seebeck coefficient and power factor are calculated.

Temperature Dependence of the Seebeck Coefficient in Zinc Oxide Thin Films

Science.gov (United States)

Noori, Amirreza; Masoumi, Saeed; Hashemi, Najmeh

2017-12-01

Thermoelectric devices are reliable tools for converting waste heat into electricity as they last long, produce no noise or vibration, have no moving elements, and their light weight makes them suitable for the outer space usage. Materials with high thermoelectric figure of merit (zT) have the most important role in the fabrication of efficient thermoelectric devices. Metal oxide semiconductors, specially zinc oxide has recently received attention as a material suitable for sensor, optoelectronic and thermoelectric device applications because of their wide direct bandgap, chemical stability, high-energy radiation endurance, transparency and acceptable zT. Understanding the thermoelectric properties of the undoped ZnO thin films can help design better ZnO-based devices. Here, we report the results of our experimental work on the thermoelectric properties of the undoped polycrystalline ZnO thin films. These films are deposited on alumina substrates by thermal evaporation of zinc in vacuum followed by a controlled oxidation process in air carried out at the 350-500 °C temperature range. The experimental setup including gradient heaters, thermometry system and Seebeck voltage measurement equipment for high resistance samples is described. Seebeck voltage and electrical resistivity of the samples are measured at different conditions. The observed temperature dependence of the Seebeck coefficient is discussed.

High Temperature Transparent Furnace Development

Science.gov (United States)

Bates, Stephen C.

1997-01-01

This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

[The electric furnace of Henri Moissan at one hundred years: connection with the electric furnace, the solar furnace, the plasma furnace?].

Science.gov (United States)

Royère, C

1999-03-01

The trace of Henri Moissan's pioneer work 100 years ago is clearly evidenced by an overview of achievements in high temperature devices; 1987: "Le four électrique" by Henri Moissan; 1948-1952: "High temperature heating in a cavity rotary kiln using focusing of solar radiation" by Félix Trombe; 1962: "The cavity rotary kiln using focused solar radiation jointly with a plasma gun" by Marc Foëx; 1970: "The rotary kiln with two plasma guns and arc transfer" by Marc Foëx; 1984: "The plasma furnace" by Electricité de France (EDF) at Renardières; 1997: "The plasma furnace" by the Atomic Energy Center (CEA) at Cadarache, the VULCANO program. The first part of this contribution is devoted to Henri Moissan. Re-reading his early book on the electric furnace, especially the first chapter and the sections on silica, carbon vapor and experiments performed in casting molten metal--the conclusions are outstanding--provides modern readers with an amazing insight into future developments. The last two parts are devoted to Félix Trombe and Marc Foëx, tracing the evolution of high temperature cavity processus leading to the solar furnace and the present day plasma furnace at the CEA. Focus is placed on research conducted by the French National Center for Scientific Research (CNRS) with the solar and plasma furnaces at Odeillo. The relationships with Henri Moissan's early work are amazing, offering a well deserved homage to this pioneer researcher.

Syntheses, crystal Structures and electronic Structures of new metal chalcoiodides Bi{sub 2}CuSe{sub 3}I and Bi{sub 6}Cu{sub 3}S{sub 10}I

Energy Technology Data Exchange (ETDEWEB)

Liang, I-Chu [Department of Chemistry, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Bilc, Daniel I. [Department of Molecular & Biomolecular Physics, National Institute for Research & Development of Isotopic & Molecular Technologies, Cluj-Napoca 400293 (Romania); Manoli, Maria [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus); Chang, Wei-Yun; Lin, Wen-Fu [Department of Chemistry, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Kyratsi, Theodora [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus); Hsu, Kuei-Fang [Department of Chemistry, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China)

2016-02-15

Two new metal chalcoiodides were synthesized by solid-state reactions at 400 °C. Crystal Data: Bi{sub 2}CuSe{sub 3}I, 1, monoclinic, C2/m, a=14.243(2) Å, b=4.1937(7) Å, c=14.647(2) Å, β=116.095(2)°, V=785.7(2) Å{sup 3}, and Z=4; Bi{sub 6}Cu{sub 3}S{sub 10}I, 2, orthorhombic, Pnma, a=17.476(2) Å, b=4.0078(4) Å, c=27.391(2) Å, V=1918.5(3) Å{sup 3}, and Z=4. Compound 1 adopts a three-dimensional structure formed by two alternative layers, which consist of BiSe{sub 5} square pyramids, BiSe{sub 4}I{sub 2} octahedra, CuSe{sub 4} tetrahedra, and CuSe{sub 2}I{sub 2} tetrahedra. Compound 2 possesses a new open framework built up of BiS{sub 5} square pyramides, BiS{sub 6} octahedra, BiS{sub 8} polyhedra, and CuS{sub 4} tetrahedra where I{sup −} anions are uniquely trapped within the tunnels. Both electronic structures reveal that bismuth and chalcogenide orbitals dominate the bandgaps. The Cu d and I p states contribute to the top of valence bands, in which the distribution of I orbitals may correspond to the relative bonding interactions in 1 and 2. The optical bandgaps determined by the diffuse reflectance spectra are 0.68 eV and 0.72 eV for 1 and 2, respectively. 1 is a p-type semiconductor with high Seebeck coefficients of 460–575 μV/K in the temperature range of 300–425 K. The electrical conductivity is 0.02 S/cm at 425 K for the undoped sample. The thermal conductivity is 0.22 W/mK at 425 K. - Graphical abstract: The hybridization of chalcogenides and iodides produces two new solids Bi2CuSe3I and Bi6Cu3S10I. The I{sup −} anions participate in distinct bonding interactions within the two structures and that is consistent with the analyses of density of states. 1 is a p-type semiconductor with an optical bandgap of 0.68 eV, which possesses high Seebeck coefficient and low lattice thermal conductivity in 300–425 K.

Magnon Polarons in the Spin Seebeck Effect.

Science.gov (United States)

Kikkawa, Takashi; Shen, Ka; Flebus, Benedetta; Duine, Rembert A; Uchida, Ken-Ichi; Qiu, Zhiyong; Bauer, Gerrit E W; Saitoh, Eiji

2016-11-11

Sharp structures in the magnetic field-dependent spin Seebeck effect (SSE) voltages of Pt/Y_{3}Fe_{5}O_{12} at low temperatures are attributed to the magnon-phonon interaction. Experimental results are well reproduced by a Boltzmann theory that includes magnetoelastic coupling. The SSE anomalies coincide with magnetic fields tuned to the threshold of magnon-polaron formation. The effect gives insight into the relative quality of the lattice and magnetization dynamics.

Development and Validation of a 3-Dimensional CFB Furnace Model

Science.gov (United States)

Vepsäläinen, Arl; Myöhänen, Karl; Hyppäneni, Timo; Leino, Timo; Tourunen, Antti

At Foster Wheeler, a three-dimensional CFB furnace model is essential part of knowledge development of CFB furnace process regarding solid mixing, combustion, emission formation and heat transfer. Results of laboratory and pilot scale phenomenon research are utilized in development of sub-models. Analyses of field-test results in industrial-scale CFB boilers including furnace profile measurements are simultaneously carried out with development of 3-dimensional process modeling, which provides a chain of knowledge that is utilized as feedback for phenomenon research. Knowledge gathered by model validation studies and up-to-date parameter databases are utilized in performance prediction and design development of CFB boiler furnaces. This paper reports recent development steps related to modeling of combustion and formation of char and volatiles of various fuel types in CFB conditions. Also a new model for predicting the formation of nitrogen oxides is presented. Validation of mixing and combustion parameters for solids and gases are based on test balances at several large-scale CFB boilers combusting coal, peat and bio-fuels. Field-tests including lateral and vertical furnace profile measurements and characterization of solid materials provides a window for characterization of fuel specific mixing and combustion behavior in CFB furnace at different loads and operation conditions. Measured horizontal gas profiles are projection of balance between fuel mixing and reactions at lower part of furnace and are used together with both lateral temperature profiles at bed and upper parts of furnace for determination of solid mixing and combustion model parameters. Modeling of char and volatile based formation of NO profiles is followed by analysis of oxidizing and reducing regions formed due lower furnace design and mixing characteristics of fuel and combustion airs effecting to formation ofNO furnace profile by reduction and volatile-nitrogen reactions. This paper presents

Valley–spin Seebeck effect in heavy group-IV monolayers

International Nuclear Information System (INIS)

Zhai, Xuechao; Wang, Shengdong; Zhang, Yan

2017-01-01

Akin to electron spin, the valley has become another highly valued degree of freedom in modern electronics, specifically after tremendous studies on monolayers of group-IV materials, i.e. graphene, silicene, germanene and stanene. Except for graphene, the other heavy group-IV monolayers have observable intrinsic spin–orbit interactions due to their buckled structures. Distinct from the usual electric or optical control of valley and spin, we here employ a temperature difference to drive electron motion in ferromagnetic heavy group-IV monolayers via designing a caloritronic device locally modulated by an interlayer electric (E z ) field. A unique valley–spin Seebeck (VSS) effect is discovered, with the current contributed only by one (the other) valley and one (the other) spin moving along one (the opposite) direction. This effect is suggested to be detected below the critical temperature about 18 K for silicene, 200 K for germanene and 400 K for stanene, arising from the characteristic valley–spin nondegenerate band structures tuned by the E z field, but cannot be driven in graphene without spin–orbit interaction. Above the critical temperature, the VSS effect is broken by overlarge temperature broadening. Besides the temperature, it is also found that the E z field can drive a transition between the VSS effect and the normal spin Seebeck effect. Further calculations indicate that the VSS effect is robust against many realistic perturbations. Our research represents a conceptually but substantially major step towards the study of the Seebeck effect. These findings provide a platform for encoding information simultaneously by the valley and spin quantum numbers of electrons in future thermal-logic circuits and energy-saving devices. (paper)

Nondestructive Imaging of an Object Using the Compact Continuous-Wave Sub-Terahertz Imaging System

Energy Technology Data Exchange (ETDEWEB)

Jang, Jin Seok; Kwon, Il Bub; Yoon, Dong Jin; Seo, Dae Cheol [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2010-08-15

This paper presented compact CW sub-THz imaging system using the terahertz transmitter(Tx) that generating 0.34 THz electromagnetic wave on based electronic device. Using 0.34 THz electromagnetic wave generated by Tx, we transmitted to sample by point by point scan method and measured transmitting terahertz wave magnitude and phase information respectively with terahertz receiver(Rx) based on sub harmonic mixer. This paper measured and compared images of several samples to obtain better imaging results by changing time delay and step distance of scanning stage which affect image resolution. Also, through the imaging measurement of various samples, we were able to assure possibility of application of terahertz wave

Nondestructive Imaging of an Object Using the Compact Continuous-Wave Sub-Terahertz Imaging System

International Nuclear Information System (INIS)

Jang, Jin Seok; Kwon, Il Bub; Yoon, Dong Jin; Seo, Dae Cheol

2010-01-01

This paper presented compact CW sub-THz imaging system using the terahertz transmitter(Tx) that generating 0.34 THz electromagnetic wave on based electronic device. Using 0.34 THz electromagnetic wave generated by Tx, we transmitted to sample by point by point scan method and measured transmitting terahertz wave magnitude and phase information respectively with terahertz receiver(Rx) based on sub harmonic mixer. This paper measured and compared images of several samples to obtain better imaging results by changing time delay and step distance of scanning stage which affect image resolution. Also, through the imaging measurement of various samples, we were able to assure possibility of application of terahertz wave

FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID REMOVAL

Energy Technology Data Exchange (ETDEWEB)

Gary M. Blythe

2004-01-01

The objective of this project has been to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The project was co-funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-99FT40718, along with EPRI, the American Electric Power Company (AEP), FirstEnergy Corporation, the Tennessee Valley Authority, and Carmeuse North America. Sulfuric acid controls are becoming of increased interest for coal-fired power generating units for a number of reasons. In particular, sulfuric acid can cause plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of selective catalytic reduction (SCR) for NOX control, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project tested the effectiveness of furnace injection of four different magnesium-based or dolomitic alkaline sorbents on full-scale utility boilers. These reagents were tested during one- to two-week tests conducted on two FirstEnergy Bruce Mansfield Plant (BMP) units. One of the sorbents tested was a magnesium hydroxide slurry byproduct from a modified Thiosorbic{reg_sign} Lime wet flue gas desulfurization process. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercially available magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners. The other three reagents were injected as slurries through air-atomizing nozzles inserted through the front wall of the upper furnace. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests on two different units. The longer-term tests were conducted to confirm sorbent effectiveness over extended operation on two

Nanoscale Thermoelectrics: A Study of the Absolute Seebeck Coefficient of Thin Films

Science.gov (United States)

Mason, Sarah J.

The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric devices have the ability to generate clean, renewable, energy out of waste heat. However promising that is, their inefficiency severely inhibits applicability and practical use. The usefulness of a thermoelectric material increases with the dimensionless quantity, ZT, which depends on the Seebeck coefficient and electrical and thermal conductivity. These characteristic material parameters have interdependent energy transport contributions that classically prohibit the optimization of one with out the detriment of another. Encouraging advancements of ZT have occurred in the past ten years due to the decoupling of the thermal and electrical conductivity. Further advancements are necessary in order to produce applicable devices. One auspicious way of decoupling or tuning energy transport properties, is through size reduction to the nanoscale. However, with reduced dimensions come complications in measuring material properties. Measurements of properties such as the Seebeck coefficient, S, are primarily contingent upon the measurement apparatus. The Seebeck coefficient is defined as the amount of voltage generated by a thermal gradient. Measuring a thermally generated voltage by traditional methods gives, the voltage measured as a linear function of the Seebeck coefficient of the leads and of the material being tested divided by the applied thermal gradient. If accurate values of the Seebeck coefficients of the leads are available, simple subtraction provides the answer. This is rarely the case in nanoscale measurement devices with leads exclusively made from thin film materials that do not have well known bulk-like thermopower values. We have developed a technique to directly

Photo-induced spin and valley-dependent Seebeck effect in the low-buckled Dirac materials

Science.gov (United States)

Mohammadi, Yawar

2018-04-01

Employing the Landauer-Buttiker formula we investigate the spin and valley dependence of Seebeck effect in low-buckled Dirac materials (LBDMs), whose band structure are modulated by local application of a gate voltage and off-resonant circularly polarized light. We calculate the charge, spin and valley Seebeck coefficients of an irradiated LBDM as functions of electronic doping, light intensity and the amount of the electric field in the linear regime. Our calculation reveal that all Seebeck coefficients always shows an odd features with respect to the chemical potential. Moreover, we show that, due to the strong spin-orbit coupling in the LBDMs, the induced thermovoltage in the irradiated LBDMs is spin polarized, and can also become valley polarized if the gate voltage is applied too. It is also found that the valley (spin) polarization of the induced thermovoltage could be inverted by reversing the circular polarization of light or reversing the direction the electric field (only by reversing the circular polarization of light).

Structural and electrochemical characterization of calcium cobaltites (Ca{sub 3}Co{sub 4}O{sub 9}) obtained by the modified Pechini Method; Caracterizacao estrutural e eletroquimica de cobaltita de calcio (Ca{sub 3}Co{sub 4}O{sub 9}) obtida pelo Metodo Pechini modificado

Energy Technology Data Exchange (ETDEWEB)

Silva, R.M.; Aquino, F. de M.; Macedo, D. A. de, E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

2016-07-01

This work deals with the synthesis and characterization of calcium cobaltite (Ca{sub 3}Co{sub 4}O{sub 9}, C349), a p-type semiconductor with high Seebeck coefficient (S), high electrical conductivity and low thermal conductivity that has emerged as thermoelectric material. The synthesis method used to obtain the compound C349 uses commercial gelatin as complexing and polymerizing agent. The obtained material was characterized by X-ray diffraction with Rietveld refinement of the diffraction data. The results indicated that the modified Pechini method using gelatin allows to obtain powders of calcium cobaltite (with monoclinic structure) associated with a small content (2% by volume) of Co{sub 3}O{sub 4} with cubic structure. Impedance spectroscopy measurements in air indicated that the composite C349/Co{sub 3}O{sub 4} is a promising material for use as solid oxide fuel cell cathode.(author)

Thermal oxidation of seeds for the hydrothermal growth of WO{sub 3} nanorods on ITO glass substrate

Energy Technology Data Exchange (ETDEWEB)

Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of Mechanical and Material Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

2015-11-30

This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO{sub 3}) nanorods. A WO{sub 3} seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm{sup −2}) than compact film (lower current density of − 0.54 and + 0.28 mA cm{sup −2}). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO{sub 3} nanorods exhibited higher electrochromic current density than WO{sub 3} compact film.

Calculating analysis of firing different composition artificial coal liquid fuels (ACLF) in the cyclone primary furnace

Energy Technology Data Exchange (ETDEWEB)

Tsepenok, A. [Novosibirsk State Technological Univ. (Russian Federation); Joint Stock company ' ' ZiO-COTES' ' , Novosibirsk (Russian Federation); Ovchinnikov, Yu. [Novosibirsk State Technological Univ. (Russian Federation); Serant, F. [Joint Stock company ' ' ZiO-COTES' ' , Novosibirsk (Russian Federation)

2013-07-01

This chapter describes the preparation technologies, results of computer simulation of combustion processes in a cyclone primary furnace during firing of artificial coal liquid fuels prepared from different coal grades and results of live testing. As a result the values of unburned carbon, NO{sub x} emissions and other concentrations in the outlet section primary furnace were estimated.

Compact interior heat exchangers for CO{sub 2} mobile heat pumping systems

Energy Technology Data Exchange (ETDEWEB)

Hafner, Armin

2003-07-01

The natural refrigerant carbon dioxide (CO{sub 2}) offers new possibilities for design of flexible, efficient and environmentally safe mobile heat pumping systems. As high-efficient car engines with less waste heat are developed, extra heating of the passenger compartment is needed in the cold season. A reversible transcritical CO{sub 2} system with gliding temperature heat rejection can give high air delivery temperature which results in rapid heating of the passenger compartment and rapid defogging or defrosting of windows. When operated in cooling mode, the efficiency of transcritical CO{sub 2} systems is higher compared to common (HFC) air conditioning systems, at most dominant operating conditions. Several issues were identified for the design of compact interior heat exchangers for automotive reversible CO{sub 2} heat pumping systems. Among theses issues are: (1) Refrigerant flow distribution, (2) Heat exchanger fluid flow circuiting, (3) Air temperature uniformity downstream of the heat exchanger, (4) Minimization of temperature approach, (5) Windshield flash fogging due to retained water inside the heat exchanger, (6) Internal beat conduction in heating mode operation, and (7) Refrigerant side pressure drop In order to provide a basis for understanding these issues, the author developed a calculation model and set up a test facility and investigated different prototype heat exchangers experimentally.

Transverse Seebeck and Peltier effect in tilted metal-semiconductor multilayer structures

International Nuclear Information System (INIS)

Reitmaier, Christina

2012-01-01

Whether in aerospace, automobile industry or in home appliances, thermoelectric effects find use in many areas of technology. This work deals with the investigation of a special form of these effects, the transversal Seebeck- and Peltier effect. Via modelling under variation of the sample parameters the cooling efficiencies, the attainable temperature differences and the Figures of merit are optimised and than suitable samples are produced according to these specifications. With these tilted metal semiconductor multilayer structures consisting of lead and bismuth telluride a transversal Peltier effect is observed. Moreover, the generation of electric power is examined via the transversal Seebeck effect. In tilted Pb-Bi2Te3 multilayers the efficiency is measured with the conversion by heat in electric power and is compared to model calculations. (orig.)

Radiography with cosmic-ray and compact accelerator muons; Exploring inner-structure of large-scale objects and landforms.

Science.gov (United States)

Nagamine, Kanetada

2016-01-01

Cosmic-ray muons (CRM) arriving from the sky on the surface of the earth are now known to be used as radiography purposes to explore the inner-structure of large-scale objects and landforms, ranging in thickness from meter to kilometers scale, such as volcanic mountains, blast furnaces, nuclear reactors etc. At the same time, by using muons produced by compact accelerators (CAM), advanced radiography can be realized for objects with a thickness in the sub-millimeter to meter range, with additional exploration capability such as element identification and bio-chemical analysis. In the present report, principles, methods and specific research examples of CRM transmission radiography are summarized after which, principles, methods and perspective views of the future CAM radiography are described.

Preparation of. beta. -spodumene glass-ceramics from blast furnace slag. Koro slag wo genryo to shita. beta. -spodumene kei kesshoka glass no seizo

Energy Technology Data Exchange (ETDEWEB)

Wang, M. (National Kaoshing Institute Technology, Kaoshiung (Rep. of China)); Hon, M. (National Cheng Kung University, Tainan (Rep. of China))

1990-07-01

Li {sub 2} O-CaO-Al {sub 2} O {sub 3} -SiO {sub 2} (LCAS) glass-ceramics were prepared from blast furnace slag by quenching in water after heating at 1,450 {degree} C for 3 hours. Blast furnace slag (40.0wt%) containing CaO, MgO, Al {sub 2} O {sub 3} and SiO {sub 2} as major components was used as a raw material, and batch compositions were modified by mixing blast furnace slag with Al {sub 2} O {sub 3}, SiO {sub 2} and Li {sub 2} CO {sub 3}, and a nucleating agent TiO {sub 2}. The A specimen with TiO {sub 2} of 7.4wt% and B specimen with 4.6wt% were prepared, and the crystallization process of the glass was examined with X-ray diffraction, electron diffraction and so forth. As a result, a major crystalline phase was {beta} -spodumene (Li {sub 2} O-Al {sub 2} O {sub 3} -4SiO {sub 2}), and the average thermal expansion coefficients of A and B were 40.1 and 47.2 {times} 10 {sup {minus} 7} / {degree} C in the temperature range from 25 to 700 {degree} C, respectively. A small amount of titanite was also observed in A as a sub-phase. 14 refs., 5 figs., 3 tabs.

Accurate on-chip measurement of the Seebeck coefficient of high mobility small molecule organic semiconductors

Science.gov (United States)

Warwick, C. N.; Venkateshvaran, D.; Sirringhaus, H.

2015-09-01

We present measurements of the Seebeck coefficient in two high mobility organic small molecules, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) and 2,9-didecyl-dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (C10-DNTT). The measurements are performed in a field effect transistor structure with high field effect mobilities of approximately 3 cm2/V s. This allows us to observe both the charge concentration and temperature dependence of the Seebeck coefficient. We find a strong logarithmic dependence upon charge concentration and a temperature dependence within the measurement uncertainty. Despite performing the measurements on highly polycrystalline evaporated films, we see an agreement in the Seebeck coefficient with modelled values from Shi et al. [Chem. Mater. 26, 2669 (2014)] at high charge concentrations. We attribute deviations from the model at lower charge concentrations to charge trapping.

Compacting biomass waste materials for use as fuel

Science.gov (United States)

Zhang, Ou

Every year, biomass waste materials are produced in large quantity. The combustibles in biomass waste materials make up over 70% of the total waste. How to utilize these waste materials is important to the nation and the world. The purpose of this study is to test optimum processes and conditions of compacting a number of biomass waste materials to form a densified solid fuel for use at coal-fired power plants or ordinary commercial furnaces. Successful use of such fuel as a substitute for or in cofiring with coal not only solves a solid waste disposal problem but also reduces the release of some gases from burning coal which cause health problem, acid rain and global warming. The unique punch-and-die process developed at the Capsule Pipeline Research Center, University of Missouri-Columbia was used for compacting the solid wastes, including waste paper, plastics (both film and hard products), textiles, leaves, and wood. The compaction was performed to produce strong compacts (biomass logs) under room temperature without binder and without preheating. The compaction conditions important to the commercial production of densified biomass fuel logs, including compaction pressure, pressure holding time, back pressure, moisture content, particle size, binder effects, and mold conditions were studied and optimized. The properties of the biomass logs were evaluated in terms of physical, mechanical, and combustion characteristics. It was found that the compaction pressure and the initial moisture content of the biomass material play critical roles in producing high-quality biomass logs. Under optimized compaction conditions, biomass waste materials can be compacted into high-quality logs with a density of 0.8 to 1.2 g/cm3. The logs made from the combustible wastes have a heating value in the range 6,000 to 8,000 Btu/lb which is only slightly (10 to 30%) less than that of subbituminous coal. To evaluate the feasibility of cofiring biomass logs with coal, burn tests were

Sintered nuclear fuel compact and method for its production

International Nuclear Information System (INIS)

Peehs, M.; Dorr, W.

1988-01-01

This patent describes a method of producing a sintered nuclear fuel compact with which reactivity losses in a nuclear reactor having long fuel element cycles are avoided, which comprises, forming a compact of a mixture of powders containing at least one nuclear fuel oxide selected from the group consisting of UO/sub 2/, PuO/sub 2/, ThO/sub 2/, mixed oxide (U, Pu)O/sub 2/ and mixed oxide (U, Th)O/sub 2/, at least one neutron poison selected from the group consisting of UB/sub x/, where x=2; 4 and/or 12 and B/sub 4/C, and sintering the compact of the mixture of powders so that the neutron piston is embedded in a sintered matrix of the nuclear fuel oxide at a treatment temperature in a range from 1000 0 C to 1400 0 C in an oxidizing sintering atmosphere, and then heat treating the sintered compact in a reducing gas atmosphere

Application of zonal combustion model for on-line furnace analysis of 575MW tangential coal firing boiler

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, B.; Karasina, E.; Livshits, B.; Talanker, A. [Israel Electric Corporation (Israel). Engineering Division

1999-07-01

An advanced code for calculating heat transfer in the boiler of furnaces is considered. The code can be used to compute the flue gas temperature in the furnace volume and the absorbed and incident heat fluxes. The number of zones in the furnace, the points of the injection of the fuel, air and flue gas recirculation (if applicable), the radiative heat transfer properties of the flue gases as well as all the factors determining performance are taken into account in the calculation. The code also predicts water wall and superheater temperature and NO{sub x} emission. The validity of the proposed model was confirmed by comparison between calculated and measured values. The predicted results show good agreement with the experimental data. The code developed is for engineers using advanced PCS at the stage of designing new boilers as well as when retrofitting and adjusting boilers already in operation. In comparison with existing complex computational models the proposed system can be used in modern monitoring systems for the furnace diagnostic problems including NO{sub x} emission. 7 refs., 11 figs.

Metallurgy of mercury in Almaden: from aludel furnaces until Pacific furnaces

International Nuclear Information System (INIS)

Tejero-Manzanares, J.; Garrido Saenz, I.; Mata Cabrera, F.; Rubio Mesas, M. L.

2014-01-01

This paper shows the different types of furnaces for roasting cinnabar, used in the metallurgy of quicksilver over the centuries of exploitation of the Almaden Mines (Spain). Some of these techniques are part of our industrial heritage. They have contributed to name UNESCO World Heritage Site the vast technological legacy of these mines recently. This research contributes to close the long way of metallurgical activity from aludel furnaces until Pacif furnaces, first and lasted technology to produce on an industrial scale. It is delved into the most relevant aspects having to do with the type, evolution and number of furnaces existing on each of the periods. (Author)

Seebeck effect in (U,Pu)Osub(2+-y) and its influence on oxygen migration

International Nuclear Information System (INIS)

Annucci, F. d'; Sari, C.; Schumacher, G.; Kernforschungszentrum Karlsruhe G.m.b.H.

1979-01-01

Thermoelectric potentials have been investigated in hypo- and hyperstoichiometric uranium-plutonium mixed oxide pellets up to temperatures of 1800 K. At low temperatures, below 1200 K the Seebeck coefficient is positive. It vanishes at temperatures between 1200 K and 1800 K and changes its sign with increasing temperatures. This behavior is explained by a change of the conductivity mechanism from p- to n-type. The absolute value of the Seebeck coefficient depends strongly on the O/M-ratio. It is big for the stoichiometric region and small for higher deviations from stoichiometry. Thermoelectric power provides one of the forces which drive ions along the temperature gradients. Another force originates in the differences of the lattice forces of the various ions, atoms, and vacancies. Both forces can be described by the heat of transport of oxygen ions which contains a thermoelectric and a thermic part. The parts are calculated using the known values of the overall heat of transport and that of the measured Seebeck coefficient. (orig./HP) [de

Densification and mechanical properties of sintered Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} ceramic composite

Energy Technology Data Exchange (ETDEWEB)

Paneto, Flavio Jose; Pereira, Joaquim Lopes; Oliveira, Jean de Lima; Jesus Filho, Edson de; Silva, Leandro Anselmo da; Cabral, Ricardo de Freitas; Santos, Claudinei dos [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Lima, Eduardo de Sousa [Institutlo Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

2014-06-15

In this work, Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} ceramic composites were developed with different proportions of Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12}, which were mixed and compacted at different pressures of 40MPa to 100MPa, being consequently sintered at 1600 deg C-2h. The sintered samples were characterized by X-ray diffraction presenting α-Al{sub 2}O{sub 3} and Y{sub 3}Al{sub 5}O{sub 12} as crystalline phases. Samples with relative densities ranging from 78 to 80% and 87 to 91% were obtained depending on the composition and the compaction pressure used. The hardness values obtained were of 1010 to 1080HV and 370- 470HV, for mixes Al{sub 2}O{sub 3}-Y{sub 3}Al{sub 5}O{sub 12} having the composition with levels of 20 and 36.5wt.%, respectively. (author)

Combination of short-length TiO{sub 2} nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhengguo [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); School of Chemistry and Chemical Engineering, Beifang University of Nationalities, Yinchuan 750021 (China); Shi, Chengwu, E-mail: shicw506@foxmail.com [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, Junjun; Xiao, Guannan; Li, Long [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China)

2017-07-15

Graphical abstract: The TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, the areal density of 500 μm{sup −2} was successfully prepared. The compact PbS quantum-dot thin film was firstly obtained on the TiO{sub 2} nanorod array by spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol. The photoelectric conversion efficiency (PCE) of the compact PbS quantum-dot thin film sensitized solar cells achieved 4.10% using spiro-OMeTAD as a hole transporting layer, while the PCE of the PbS quantum-dot sensitized solar cells was only 0.54%. - Highlights: • Preparation of TiO{sub 2} nanorod arrays with the length of 600 nm, diameter of 20 nm. • The compact PbS QD thin film and short-length TiO{sub 2} nanorod array were combined. • EDT addition improved PbS nanoparticle coverage and photovoltaic performance. • The compact PbS QD thin film sensitized solar cell achieved the PCE of 4.10%. - Abstract: Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm{sup −2} is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO{sub 2} nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion

Accurate on-chip measurement of the Seebeck coefficient of high mobility small molecule organic semiconductors

Directory of Open Access Journals (Sweden)

C. N. Warwick

2015-09-01

Full Text Available We present measurements of the Seebeck coefficient in two high mobility organic small molecules, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT and 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT. The measurements are performed in a field effect transistor structure with high field effect mobilities of approximately 3 cm2/V s. This allows us to observe both the charge concentration and temperature dependence of the Seebeck coefficient. We find a strong logarithmic dependence upon charge concentration and a temperature dependence within the measurement uncertainty. Despite performing the measurements on highly polycrystalline evaporated films, we see an agreement in the Seebeck coefficient with modelled values from Shi et al. [Chem. Mater. 26, 2669 (2014] at high charge concentrations. We attribute deviations from the model at lower charge concentrations to charge trapping.

Transverse peltier effect in Pb-Bi{sub 2}Te{sub 3} multilayer structures

Energy Technology Data Exchange (ETDEWEB)

Reitmaier, Christina; Walther, Franziska; Kyarad, Amir; Lengfellner, Hans [University of Regensburg (Germany)

2009-07-01

Metal-semiconductor multilayer structures show, according to model calculations, large anisotropy in their electrical and thermal transport properties. Multilayer stacks consisting of alternating layers of Pb and n-type Bi{sub 2}Te{sub 3} and prepared by a heating procedure displayed large thermoelectric anisotropy up to {delta}S{approx}200 {mu} V/K, depending on the thickness ratio p=d{sub BiTe}/d{sub Pb}, where d{sub BiTe} and d{sub Pb} are the thicknesses of Bi{sub 2}Te{sub 3} and Pb layers, respectively. From multilayer stacks, tilted samples with layers inclined with respect to the sample surface where obtained by cutting stacks obliquely to the stack axis. Non-zero off-diagonal elements in the Seebeck-tensor describing the thermopower of tilted samples allow for the occurance of a transverse Peltier effect. Experimental results demonstrate cooling by the transverse Peltier effect and are compared to model calculations.

Monoclinic superstructure of Pr{sub 3}Rh{sub 4}Ge{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Vosswinkel, Daniel; Hoffmann, Rolf-Dieter; Greiwe, Magnus; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2016-07-01

Pr{sub 3}Rh{sub 4}Ge{sub 4} was synthesized by melting of the elements in an arc-melting furnace followed by annealing in a sealed tantalum ampoule in a muffle furnace. Structure refinement was based on temperature dependent single-crystal X-ray diffractometer data. At ambient temperature Pr{sub 3}Rh{sub 4}Ge{sub 4} adopts the U{sub 3}Ni{sub 4}Si{sub 4} type structure with strongly enhanced anisotropic displacement parameters for Rh1. Below 230 K additional reflections start to appear and at 110 K the structure could be described with the (3+1)D superspace group I2/m(α0γ)00; α=1/2, γ=1/2; (Z=2). This commensurately modulated structure could be refined with 1448 F{sup 2} values, 39 variables and residuals of wR=0.0417 for the main reflections and wR=0.1520 for the satellites of 1{sup st} order, [a=408.36(2), b=421.12(3) and c=2504.4(2) pm]. The commensurate description could be transformed to a 3D supercell with space group A2/m and Z=4: a=816.72(2), b=421.12(3), c=2537.5(1) pm, β=99.26(1) , 1448 F{sup 2} values, 69 variables and wR=0.0499. The relation of the U{sub 3}Ni{sub 4}Si{sub 4} type structure, the (3+1)D modulated and the 3D supercell is discussed on the basis of a group-subgroup scheme. Temperature dependent magnetic susceptibility data reveal Curie-Weiss paramagnetism with an experimental moment of 3.72(2) μ{sub B}/Pr atom and a Weiss constant of -12.6(5) K. No magnetic ordering is evident down to 3 K.

Advanced steel reheat furnace

Energy Technology Data Exchange (ETDEWEB)

Moyeda, D.; Sheldon, M.; Koppang, R. [Energy and Environmental Research Corp., Irvine, CA (United States); Lanyi, M.; Li, X.; Eleazer, B. [Air Products and Chemicals, Inc., Allentown, PA (United States)

1997-10-01

Energy and Environmental Research Corp. (EER) under a contract from the Department of Energy is pursuing the development and demonstration of an Advanced Steel Reheating Furnace. This paper reports the results of Phase 1, Research, which has evaluated an advanced furnace concept incorporating two proven and commercialized technologies previously applied to other high temperature combustion applications: EER`s gas reburn technology (GR) for post combustion NOx control; and Air Product`s oxy-fuel enrichment air (OEA) for improved flame heat transfer in the heating zones of the furnace. The combined technologies feature greater production throughput with associated furnace efficiency improvements; lowered NOx emissions; and better control over the furnace atmosphere, whether oxidizing or reducing, leading to better control over surface finish.

Description of a Sensitive Seebeck Calorimeter Used for Cold Fusion Studies

Science.gov (United States)

Storms, Edmund

A sensitive and stable Seebeck calorimeter is described and used to determine the heat of formation of PdD. This determination can be used to show that such calorimeters are sufficiently accurate to measure the LENR effect and give support to the claims.

Effect of Sb content on the thermoelectric properties of annealed CoSb{sub 3} thin films deposited via RF co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Aziz, E-mail: aziz_ahmed@ust.ac.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Han, Seungwoo, E-mail: swhan@kimm.re.kr [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 305-350 (Korea, Republic of); Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

2017-06-30

Graphical abstract: The X-ray diffraction patterns and temperature dependence of the Seebeck coefficient of the annealed Co–Sb thin films. - Highlights: • CoSb{sub 3} phase thin films were prepared using RF co sputtering method. • Thin film thermoelectric properties were hugely dependent on Sb content. • All thin films shows n-type conduction behavior at high temperatures. • The thin films with excess Sb possess the largest Seebeck coefficient. • The thin films with CoSb{sub 2} phase possess the largest power factor. - Abstract: A series of CoSb{sub 3} thin films with Sb contents in the range 70–79 at.% were deposited at room temperature via RF co-sputtering. The thin films were amorphous in the as-deposited state and annealed at 300 °C for 3 h to obtain crystalline samples. The annealed thin films were characterized using scanning electron microscopy and X-ray diffraction (XRD), and these data indicate that the films exhibited good crystallinity. The XRD patterns indicate single-phase CoSb{sub 3} thin films in the Sb-rich samples. For the Sb-deficient samples, however, mixed-phase thin films consisting of CoSb{sub 2} and CoSb{sub 3} components were obtained. The electrical and thermoelectric properties were measured at temperatures up to 760 K and found to be highly sensitive to the phases that were present. We observed a change in the thermoelectric properties of the films from p-type at low temperatures to n-type at high temperatures, which indicates potential applications as n-type thermoelectric thin films. A large Seebeck coefficient and power factor was obtained for the single-phase CoSb{sub 3} thin films. The CoSb{sub 2} phase thin films were also found to possess a significant Seebeck coefficient, which coupled with the much smaller electrical resistivity, provided a larger power factor than the single-phase CoSb{sub 3} thin films. We report maximum power factor of 7.92 mW/m K{sup 2} for the CoSb{sub 2}-containing mixed phase thin film and 1

Model Predictive Control of the Exit Part Temperature for an Austenitization Furnace

Directory of Open Access Journals (Sweden)

Hari S. Ganesh

2016-12-01

Full Text Available Quench hardening is the process of strengthening and hardening ferrous metals and alloys by heating the material to a specific temperature to form austenite (austenitization, followed by rapid cooling (quenching in water, brine or oil to introduce a hardened phase called martensite. The material is then often tempered to increase toughness, as it may decrease from the quench hardening process. The austenitization process is highly energy-intensive and many of the industrial austenitization furnaces were built and equipped prior to the advent of advanced control strategies and thus use large, sub-optimal amounts of energy. The model computes the energy usage of the furnace and the part temperature profile as a function of time and position within the furnace under temperature feedback control. In this paper, the aforementioned model is used to simulate the furnace for a batch of forty parts under heuristic temperature set points suggested by the operators of the plant. A model predictive control (MPC system is then developed and deployed to control the the part temperature at the furnace exit thereby preventing the parts from overheating. An energy efficiency gain of 5.3 % was obtained under model predictive control compared to operation under heuristic temperature set points tracked by a regulatory control layer.

Cold compaction behavior of nano-structured Nd-Fe-B alloy powders prepared by different processes

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaoya [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Hu, Lianxi, E-mail: hulx@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Erde [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2013-02-25

Graphical abstract: Relative density enhancement and nanocrystallization of Nd{sub 2}Fe{sub 14}B phase are two major effective means to improve magnetic properties. Since the matrix Nd{sub 2}Fe{sub 14}B phase in the starting Nd-Fe-B alloy can be disproportionated into a nano-structured mixture of NdH{sub 2.7}, Fe{sub 2}B, and {alpha}-Fe phases during mechanical milling in hydrogen. It is thus important to study the densification behavior of nanocrystalline powders to evaluate and predict the cold compactibility of powders. By comparison with the as milled as well as melt-spun Nd{sub 16}Fe{sub 76}B{sub 8} alloy powders, we find that the as-disproportionated Nd{sub 16}Fe{sub 76}B{sub 8} alloy powder exhibits the best cold compactibility. As evident from the illustration presented below, compaction parameters (representing the powder compactibility) have been determined by fitting density-pressure data with double logarithm compaction equation. Densification mechanisms involved during cold compaction process are clarified in our work by referring to microstructure observation of samples prepared by various methods. As a result, highly densified green magnet compact can be obtained by cold pressing of as-disproportionated NdFeB alloy powders. Highlights: Black-Right-Pointing-Pointer Nano-structured disproportionated Nd-Fe-B alloy powders by mechanical milling in hydrogen. Black-Right-Pointing-Pointer Highly densified green magnet compact by cold pressing of as-disproportionated Nd-Fe-B alloy powders. Black-Right-Pointing-Pointer Density-pressure data fitted well by an empirical powder compaction model. Black-Right-Pointing-Pointer As-disproportionated powder showed better compactibility than as milled and melt-spun counterparts. Black-Right-Pointing-Pointer The effects of physical properties on powder compactibility and densification mechanisms are clarified. - Abstract: The compaction behavior of nano-structured Nd{sub 16}Fe{sub 76}B{sub 8} (atomic ratio) alloy

Interplay of Peltier and Seebeck Effects in Nanoscale Nonlocal Spin Valves

NARCIS (Netherlands)

Bakker, F. L.; Slachter, A.; Adam, J-P; van Wees, B. J.

2010-01-01

We have experimentally studied the role of thermoelectric effects in nanoscale nonlocal spin valve devices. A finite element thermoelectric model is developed to calculate the generated Seebeck voltages due to Peltier and Joule heating in the devices. By measuring the first, second, and third

Description of a sensitive seebeck calorimeter used for cold fusion studies

International Nuclear Information System (INIS)

Storms, Edmund

2006-01-01

A sensitive and stable Seebeck calorimeter is described and used to determine the heat of formation of PdD. This determination can be used to show that such calorimeters are sufficiently accurate to measure the LENR effect and give support to the claims. (author)

Coherent states for quantum compact groups

Energy Technology Data Exchange (ETDEWEB)

Jurco, B. [European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Stovicek, P. [Ceske Vysoke Uceni Technicke, Prague (Czech Republic). Dept. of Mathematics]|[CTU, Prague (Czech Republic). Doppler Inst.

1996-12-01

Coherent states are introduced and their properties are discussed for simple quantum compact groups A{sub l}, B{sub l}, C{sub l} and D{sub l}. The multiplicative form of the canonical element for the quantum double is used to introduce the holomorphic coordinates on a general quantum dressing orbit. The coherent state is interpreted as a holomorphic function on this orbit with values in the carrier Hilbert space of an irreducible representation of the corresponding quantized enveloping algebra. Using Gauss decomposition, the commutation relations for the holomorphic coordinates on the dressing orbit are derived explicitly and given in a compact R-matrix formulation (generalizing this way the q-deformed Grassmann and flag manifolds). The antiholomorphic realization of the irreducible representations of a compact quantum group (the analogue of the Borel-Weil construction) is described using the concept of coherent state. The relation between representation theory and non-commutative differential geometry is suggested. (orig.)

An experimental approach of decoupling Seebeck coefficient and electrical resistivity

Science.gov (United States)

Muhammed Sabeer N., A.; Paulson, Anju; Pradyumnan, P. P.

2018-04-01

The Thermoelectrics (TE) has drawn increased attention among renewable energy technologies. The performance of a thermoelectric material is quantified by a dimensionless thermoelectric figure of merit, ZT=S2σT/κ, where S and σ vary inversely each other. Thus, improvement in ZT is not an easy task. So, researchers have been trying different parameter variations during thin film processing to improve TE properties. In this work, tin nitride (Sn3N4) thin films were deposited on glass substrates by reactive RF magnetron sputtering and investigated its thermoelectric response. To decouple the covariance nature of Seebeck coefficient and electrical resistivity for the enhancement of power factor (S2σ), the nitrogen gas pressure during sputtering was reduced. Reduction in nitrogen gas pressure reduced both sputtering pressure and amount of nitrogen available for reaction during sputtering. This experimental approach of combined effect introduced preferred orientation and stoichiometric variations simultaneously in the sputtered Sn3N4 thin films. The scattering mechanism associated with these variations enhanced TE properties by independently drive the Seebeck coefficient and electrical resistivity parameters.

Structure of Ti{sub 3}SiC{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Rawn, C.J.; Payzant, E.A.; Hubbard, C.R. [Oak Ridge National Lab., TN (United States); Barsoum, M.W.; El-Raghy, T. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Engineering

1998-11-01

Earlier high temperature structure analysis by neutron powder diffraction suggested that Si vacancies were created when Ti{sub 3}SiC{sub 2} was heated. A specimen that was heated to 906 C overnight was later examined at room temperature. For this subsequent room temperature data set refinement of the Si site occupancies in the Ti{sub 3}SiC{sub 2} structure did not support the hypothesis that Si vacancies were being created when the sample was held at elevated temperatures in a vacuum furnace.

In-service testing of Ni{sub 3}Al coupons and trays in carburizing furnaces at Delphi Saginaw. CRADA final report

Energy Technology Data Exchange (ETDEWEB)

Sikka, V.K.; Santella, M.L.; Viswanathan, S.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Chatterjee, M. [General Motors Corporaion, Saginaw Division (United States)

1998-08-01

This Cooperative Research and Development Agreement (CRADA) report deals with the development of nickel aluminide alloy for improved longer life heat-resistant fixture assemblies for batch and continuous pusher carburizing furnaces. The nickel aluminide development was compared in both coupon and component testing with the currently used Fe-Ni-Cr heat-resisting alloy known as HU. The specific goals of the CRADA were: (1) casting process development, (2) characterization and possible modification of the alloy composition to optimize its manufacturing ability and performance under typical furnace operating conditions, and (3) testing and evaluation of specimens and prototype fixtures. In support of the CRADA objectives, coupons of nickel aluminide and the HU alloy were installed in both batch and pusher furnaces. The coupons were taken from two silicon levels and contained welds made with two different filler compositions (IC-221LA and IC-221W). Both nickel-aluminide and HU coupons were removed from the batch and pusher carburizing furnace at time intervals ranging from one month to one year. The exposed coupons were cut and mounted for metallographic, hardness, and microprobe analysis. The results of the microstructural analysis have been transmitted to General Motors Corporation, Saginaw Division (Delphi Saginaw) through reports that were presented at periodic CRADA review meetings. Based on coupon testing and verification of the coupon results with the testing of trays, Delphi Saginaw moved forward with the use of six additional trays in a batch furnace and two assemblies in a pusher furnace. Fifty percent of the trays and fixtures are in the as-cast condition and the remaining trays and fixtures are in the preoxidized condition. The successful operating experience of two assemblies in the pusher furnace for nearly a year formed the basis for a production run of 63 more assemblies. The production run required melting of 94 heats weighing 500 lb. each. Twenty

COMPACTION OF LITHIUM-SILICATE CERAMICS USING SPARK PLASMA SINTERING

Directory of Open Access Journals (Sweden)

Tomas Frantisek Kubatik

2016-12-01

Full Text Available This paper deals with the compaction of ceramics based on lithium-silicate by spark plasma sintering (SPS. The initial powder was prepared by calcination in a resistance furnace at a temperature of 1300 °C with the ratio of Li/Si = 1. Compacting by SPS was carried out at temperatures of 800 - 1000 °C with a maximum pressure of 80 MPa. Samples with open porosity of less than 1 % were prepared at the temperature of 1000 °C. According to the quantitative Rietveld refinement of x-ray diffraction data, the dominant phases in all samples were Li₂Si₂O₅ and Li₂SiO₃, together representing over 80 wt. % of the sintered material.

A giant enhancement of CMR in Eu{sub 0.6}Ca{sub 0.4}B{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Glushkov, V V; Bogach, A V; Demishev, S V; Sluchanko, N E [A.M.Prokhorov General Physics Institute of RAS, 38, Vavilov str., Moscow 119991 (Russian Federation); Anisimov, M A [Moscow Institute of Physics and Technology, 9, Institutskii per., Dolgoprudny, Moscow Region 141700 (Russian Federation); Churkin, O A; Kuznetsov, A V [Moscow Engineering Physics Institute, 31, Kashirskoe Shosse, Moscow 115409 (Russian Federation); Filipov, V B; Levchenko, A V; Shitsevalova, N Yu [I. Frantsevich Institute for Problems of Materials Science NAS, 3, Krzhyzhanovsky str., Kiev 03680 (Ukraine); Flachbart, K, E-mail: glushkov@lt.gpi.r [Centre of Low Temperature Physics, IEP SAS and IPS FS UPJS, Kosice SK-04001 (Slovakia)

2010-01-15

The transport and magnetic properties of Eu{sub 0.6}Ca{sub 0.4}B{sub 6} single crystals have been studied at temperatures 1.8-300 K in magnetic fields up to 80 kOe. It was found that lowering of temperature results in a drastic increase of magnetoresistance up to the values of {rho}(0)/{rho}(H){approx}7{center_dot}10{sup 5} detected below 6K. The Hall and Seebeck effect measurements showed that colossal magnetoresistance (CMR) observed in Eu{sub 0.6}Ca{sub 0.4}B{sub 6} is accompanied by a crossover from hole-like to electron-like regime of charge transport induced by applied magnetic field. Hall mobility values {mu}{sub H{approx}}200-350 cm{sup 2}/(Vs) estimated for the high conductive state of Eu{sub 0.6}Ca{sub 0.4}B{sub 6} in the presence of strong substitutional disorder were proved to be comparable with these ones measured for undoped EuB{sub 6}. The anomalous behaviour of transport and magnetic parameters is discussed in terms of metal-insulator transition earlier predicted for this low carrier density system within double exchange model by V M Pereira et al., Phys. Rev. Lett. 93 147202 (2004).

Thermoelectric properties of V{sub 2}O{sub 5} thin films deposited by thermal evaporation

Energy Technology Data Exchange (ETDEWEB)

Santos, R.; Loureiro, J., E-mail: joa.loureiro@gmail.com; Nogueira, A.; Elangovan, E.; Pinto, J.V.; Veiga, J.P.; Busani, T.; Fortunato, E.; Martins, R.; Ferreira, I., E-mail: imf@fct.unl.pt

2013-10-01

This work reports the structural, optical, electrical and thermoelectric properties of vanadium pentoxide (V{sub 2}O{sub 5}) thin films deposited at room temperature by thermal evaporation on Corning glass substrates. A post-deposition thermal treatment up to 973 K under atmospheric conditions induces the crystallization of the as-deposited amorphous films with an orthorhombic V{sub 2}O{sub 5} phase with grain sizes around 26 nm. As the annealing temperature rises up to 773 K the electrical conductivity increases. The films exhibit thermoelectric properties with a maximum Seebeck coefficient of −218 μV/K and electrical conductivity of 5.5 (Ω m){sup −1}. All the films show NIR-Vis optical transmittance above 60% and optical band gap of 2.8 eV.

CFD study of temperature distribution in full scale boiler adopting in-furnace coal blending

International Nuclear Information System (INIS)

Fadhil, S S A; Hasini, H; Shuaib, N H

2013-01-01

This paper describes the investigation of temperature characteristics of an in-furnace combustion using different coals in a 700 MW full scale boiler. Single mixture fraction approach is adopted for combustion model of both primary and secondary coals. The primary coal was based on the properties of Adaro which has been used as the design coal for the boiler under investigation. The secondary blend coal was selected based on sub-bituminous coal with higher calorific value. Both coals are simultaneously injected into the furnace at alternate coal burner elevations. The general prediction of the temperature contours at primary combustion zone shows identical pattern compared with conventional single coal combustion in similar furnace. Reasonable agreement was achieved by the prediction of the average temperature at furnace exit. The temperature distribution is at different furnace elevation is non-uniform with higher temperature predicted at circumferential 'ring-like' region at lower burner levels for both cases. The maximum flame temperature is higher at the elevation where coal of higher calorific value is injected. The temperature magnitude is within the accepTable limit and the variations does not differ much compared to the conventional single coal combustion.

Skyrmionic spin Seebeck effect via dissipative thermomagnonic torques

Science.gov (United States)

Kovalev, Alexey A.

2014-06-01

We derive thermomagnonic torque and its "β-type" dissipative correction from the stochastic Landau-Lifshitz-Gilbert equation. The β-type dissipative correction describes viscous coupling between magnetic dynamics and magnonic current and it stems from spin mistracking of the magnetic order. We show that thermomagnonic torque is important for describing temperature gradient induced motion of skyrmions in helical magnets while dissipative correction plays an essential role in generating transverse Magnus force. We propose to detect such skyrmionic motion by employing the transverse spin Seebeck effect geometry.

The Seebeck coefficient and the Peltier effect in a polymer electrolyte membrane cell with two hydrogen electrodes

International Nuclear Information System (INIS)

Kjelstrup, S.; Vie, P.J.S.; Akyalcin, L.; Zefaniya, P.; Pharoah, J.G.; Burheim, O.S.

2013-01-01

Highlights: • The heat change associated with the hydrogen electrode in a polymer electrolyte cell is determined from Seebeck coefficient measurements. • When electric current is passed from left to right in the outer circuit, the anode becomes warmer, while the cathode becomes colder in a thermoelectric cell with hydrogen electrodes. • At Soret equilibrium for water in the fuel cell, most of the entropy of the fuel cell reaction is generated at the anode. -- Abstract: We report that the Seebeck coefficient of a Nafion membrane cell with hydrogen electrodes saturated with water vapour, at 1 bar hydrogen pressure and 340 K, is equal to 670 ± 50 μV/K, meaning that the entropy change of the anode reaction at reversible conditions (67 J/(K mol)) corresponds to a reversible heat release of 22 kJ/mol. The transported entropy of protons across the membrane at Soret equilibrium was estimated from this value to 1 ± 5 J/(K mol). The results were supported by the expected variation in the Seebeck coefficient with the hydrogen pressure. We report also the temperature difference of the electrodes, when passing electric current through the cell, and find that the anode is heated (a Peltier heat effect), giving qualitative support to the result for the Seebeck coefficient. The Seebeck and Peltier effects are related by non-equilibrium thermodynamics theory, and the Peltier heat of the cathode in the fuel cell is calculated for steady state conditions to 6 ± 2 kJ/mol at 340 K. The division of the reversible heat release between the anode and the cathode, can be expected to vary with the current density, as the magnitude of the current density can have a big impact on water transport and water concentration profile

The effect of TiO{sub 2} nanoparticles on water permeability and thermal and mechanical properties of high strength self-compacting concrete

Energy Technology Data Exchange (ETDEWEB)

Nazari, Ali, E-mail: alinazari84@aut.ac.ir [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of); Riahi, Shadi [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of)

2010-12-15

Research highlights: {yields} TiO{sub 2} nanoparticles effects on self-compacting concrete. {yields} Strength assessments. {yields} Water permeability. {yields} Thermal properties. {yields} Pore structure. {yields} Microstructure evaluations. - Abstract: In this work, strength assessments and coefficient of water absorption of high performance self-compacting concrete containing different amounts of TiO{sub 2} nanoparticles have been investigated. The results indicate that the strength and the resistance to water permeability of the specimens are improved by adding TiO{sub 2} nanoparticles in the cement paste up to 4.0 wt%. TiO{sub 2} nanoparticles, as a result of increased crystalline Ca(OH){sub 2} amount especially at the early age of hydration, could accelerate C-S-H gel formation and hence increase the strength of the concrete specimens. In addition, TiO{sub 2} nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that TiO{sub 2} nanoparticles could improve mechanical and physical properties of the concrete specimens.

CFD simulation of gas and particles combustion in biomass furnaces

Energy Technology Data Exchange (ETDEWEB)

Griselin, Nicolas

2000-11-01

In this thesis, gas and particle combustion in biomass furnaces is investigated numerically. The aim of this thesis is to use Computational Fluid Dynamics (CFD) technology as an effective computer based simulation tool to study and develop the combustion processes in biomass furnaces. A detailed model for the numerical simulation of biomass combustion in a furnace, including fixed-bed modeling, gas-phase calculation (species distribution, temperature field, flow field) and gas-solid two-phase interaction for flying burning particles is presented. This model is used to understand the mechanisms of combustion and pollutant emissions under different conditions in small scale and large scale furnaces. The code used in the computations was developed at the Division of Fluid Mechanics, LTH. The flow field in the combustion enclosure is calculated by solving the Favre-averaged Navier-Stokes equations, with standard {kappa} - {epsilon} turbulence closure, together with the energy conservation equation and species transport equations. Discrete transfer method is used for calculating the radiation source term in the energy conservation equation. Finite difference is used to solve the general form of the equation yielding solutions for gas-phase temperatures, velocities, turbulence intensities and species concentrations. The code has been extended through this work in order to include two-phase flow simulation of particles and gas combustion. The Favre-averaged gas equations are solved in a Eulerian framework while the submodels for particle motion and combustion are used in the framework of a Lagrangian approach. Numerical simulations and measurement data of unburned hydrocarbons (UHC), CO, H{sub 2}, O{sub 2} and temperature on the top of the fixed bed are used to model the amount of tar and char formed during pyrolysis and combustion of biomass fuel in the bed. Different operating conditions are examined. Numerical calculations are compared with the measured data. It is

Inhomogeneous compact extra dimensions

Energy Technology Data Exchange (ETDEWEB)

Bronnikov, K.A. [Center of Gravity and Fundamental Metrology, VNIIMS, 46 Ozyornaya st., Moscow 119361 (Russian Federation); Budaev, R.I.; Grobov, A.V.; Dmitriev, A.E.; Rubin, Sergey G., E-mail: kb20@yandex.ru, E-mail: buday48@mail.ru, E-mail: alexey.grobov@gmail.com, E-mail: alexdintras@mail.ru, E-mail: sergeirubin@list.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409 Moscow (Russian Federation)

2017-10-01

We show that an inhomogeneous compact extra space possesses two necessary features— their existence does not contradict the observable value of the cosmological constant Λ{sub 4} in pure f ( R ) theory, and the extra dimensions are stable relative to the 'radion mode' of perturbations, the only mode considered. For a two-dimensional extra space, both analytical and numerical solutions for the metric are found, able to provide a zero or arbitrarily small Λ{sub 4}. A no-go theorem has also been proved, that maximally symmetric compact extra spaces are inconsistent with 4D Minkowski space in the framework of pure f ( R ) gravity.

Furnace

Energy Technology Data Exchange (ETDEWEB)

Osintsev, V V; Khidiyatov, A M

1981-01-01

The purpose of the invention is to improve the operating efficiency of the furnace device containing prefurnaces connected to the main combustion chamber. For this purpose in the proposed furnace device is equipped with prefurnaces with burners, rectangular vertical chamber of combustion is equipped with central hearth projection. As indicated by studies, the hearth projection of the indicated projections promotes the development of transverse streams which guarantee effective mixing of the combustion products in the upper part of the combustion chamber 3. This reduces the nonuniformity of temperature at the outlet from the latter, decreases the probability of slagging and hot spots on the heating surface.

Chemical bath deposited rutile TiO{sub 2} compact layer toward efficient planar heterojunction perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Liang, Chao, E-mail: lc401997413@qq.com [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Wu, Zhenhua, E-mail: 80116243@qq.com [Henan Information Engineering School, Zhengzhou 450000 (China); Li, Pengwei, E-mail: pengweili001@126.com [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Fan, Jiajie, E-mail: fanjiajie@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhang, Yiqiang, E-mail: yqzhang@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Shao, Guosheng, E-mail: gsshao@zzu.edu.cn [State Centre for International Cooperation on Designer Low-Carbon and Environmental Material (SCICDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China)

2017-01-01

Highlights: • Rutile TiO{sub 2} thin film can be grown on FTO substrate below 100 °C. • 200 mM TiCl{sub 4} precursor solution results in the best PSC performance. • UV/O{sub 3} treatment can reduce the carrier recombination effectively. • Over 12% power conversion efficiency can be achieved for PSCs. - Abstract: TiO{sub 2} is a best choice of electron transport layers in perovskite solar cells, due to its high electron mobility and stability. However, traditional TiO{sub 2} processing method requires rather high annealing temperature (>500 °C), preventing it from application to flexible devices. Here, we show that TiO{sub 2} thin films can be synthesized via chemical bath deposition below 100 °C. Typically, a compact layer of rutile TiO{sub 2} is deposited onto fluorine-doped tin oxide (FTO) coated substrates, in an aqueous TiCl{sub 4} solution at 70 °C. Through the optimization of precursor concentration and ultraviolet-ozone surface modification, over 12% power conversion efficiency can be achieved for CH{sub 3}NH{sub 3}PbI{sub 3} based perovskite solar cells. These findings offer a potential low-temperature technical solution in using TiO{sub 2} thin film as an effective transport layer for flexible perovskite solar cells.

Oil injection into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Dongsheng Liao; Mannila, P.; Haerkki, J.

1997-12-31

Fuel injection techniques have been extensively used in the commercial blast furnaces, a number of publications concerning the fuels injection have been reported. This present report only summarizes the study achievements of oil injection due to the research need the of authors, it includes the following parts: First, the background and the reasons reducing coke rate of oil injection are analyzed. Reducing coke rate and decreasing the ironmaking costs are the main deriving forces, the contents of C, H and ash are direct reasons reducing coke rate. It was also found that oil injection had great effects on the state of blast furnace, it made operation stable, center gas flow develop fully, pressure drop increase, descent speed of burden materials decrease and generation of thermal stagnation phenomena, the quality of iron was improved. Based on these effects, as an ideal mean, oil injection was often used to adjust the state of blast furnace. Secondly, combustion behavior of oil in the raceway and tuyere are discussed. The distribution of gas content was greatly changed, the location of CO, H{sub 2} generation was near the tuyere; the temperature peak shifts from near the raceway boundary to the tuyere. Oxygen concentration and blast velocity were two important factors, it was found that increasing excess oxygen ratio 0.9 to 1.3, the combustion time of oil decreases 0.5 msec, an increase of the blast velocity results in increasing the flame length. In addition, the nozzle position and oil rate had large effects on the combustion of oil. Based on these results, the limit of oil injection is also discussed, soot formation is the main reason limiting to further increase oil injection rate, it was viewed that there were three types of soot which were generated under blast furnace operating conditions. The reason generating soot is the incomplete conversion of the fuel. Finally, three methods improving combustion of oil in the raceway are given: Improvement of oil

Influence of temperature on thermoelectric properties of Fe{sub x}Co{sub 1−x}S{sub 2} thin films: A semiconductor to semimetal conversion

Energy Technology Data Exchange (ETDEWEB)

Clamagirand, J.M.; Ares, J.R., E-mail: joser.ares@uam.es; Flores, E.; Diaz-Chao, P.; Leardini, F.; Ferrer, I.J.; Sánchez, C.

2016-02-01

In this work, we investigate the thermoelectric properties of p and n-type thin films obtained by cobalt doping of FeS{sub 2}. Films were synthesized by direct sulfuration of Co–Fe thin bilayers at 300 °C. It is found that at room temperature (RT), the Seebeck coefficient is reduced from 80 μV/K to − 70 μV/K when Co concentration is increased and the electrical resistivity of the films is decreased two orders of magnitude. X-ray diffraction and Raman measurements point out that Co is replacing Fe into the pyrite lattice and, subsequently is promoting a semiconductor to semimetal conversion. The influence of temperature on transport properties of different Fe{sub x}Co{sub 1−x}S{sub 2} films has been investigated. Whereas the Seebeck coefficient is hardly modified, the film resistivity is drastically decreased when temperature increases what has been attributed to the thermal activation of electrical carriers. The influence of Co doping on the band scheme of FeS{sub 2} is shown. To this aim, donor and acceptor states are included into its forbidden gap. Whereas the band scheme of FeS{sub 2} exhibits an acceptor level with an E = 0.11 ± 0.03 eV above the top of the valence band due to iron vacancies, a wide donor level close to the bottom of the conduction band (E = 0.08 ± 0.05 eV) is created by the progressive replacement of iron by cobalt into the FeS{sub 2} lattice. - Highlights: • Thermoelectric properties of pyrite and Co-doped pyrite thin films were measured. • Whereas ρ decreases, S remains practically unaltered on increasing temperature (RT-300 °C). • On increasing Co-concentration, films exhibit a p semiconductor to n type semimetal conversion. • Donor states close to the botton of the conduction band are created by Co doping. • Energy of the donor level decreases and gets wider due to Co-concentration.

Estimating Seebeck Coefficient of a p-Type High Temperature Thermoelectric Material Using Bee Algorithm Multi-layer Perception

Science.gov (United States)

Uysal, Fatih; Kilinc, Enes; Kurt, Huseyin; Celik, Erdal; Dugenci, Muharrem; Sagiroglu, Selami

2017-08-01

Thermoelectric generators (TEGs) convert heat into electrical energy. These energy-conversion systems do not involve any moving parts and are made of thermoelectric (TE) elements connected electrically in a series and thermally in parallel; however, they are currently not suitable for use in regular operations due to their low efficiency levels. In order to produce high-efficiency TEGs, there is a need for highly heat-resistant thermoelectric materials (TEMs) with an improved figure of merit ( ZT). Production and test methods used for TEMs today are highly expensive. This study attempts to estimate the Seebeck coefficient of TEMs by using the values of existing materials in the literature. The estimation is made within an artificial neural network (ANN) based on the amount of doping and production methods. Results of the estimations show that the Seebeck coefficient can approximate the real values with an average accuracy of 94.4%. In addition, ANN has detected that any change in production methods is followed by a change in the Seebeck coefficient.

Compact magnetic confinement fusion: Spherical torus and compact torus

Directory of Open Access Journals (Sweden)

Zhe Gao

2016-05-01

Full Text Available The spherical torus (ST and compact torus (CT are two kinds of alternative magnetic confinement fusion concepts with compact geometry. The ST is actually a sub-category of tokamak with a low aspect ratio; while the CT is a toroidal magnetic configuration with a simply-connected geometry including spheromak and field reversed pinch. The ST and CT have potential advantages for ultimate fusion reactor; while at present they can also provide unique fusion science and technology contributions for mainstream fusion research. However, some critical scientific and technology issues should be extensively investigated.

Electronic structure and high thermoelectric properties of a new material Ba{sub 3}Cu{sub 20}Te{sub 13}

Energy Technology Data Exchange (ETDEWEB)

Yang, Gui, E-mail: kuiziyang@126.com [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan, 455000 (China); Wu, Jinghe [Department of Physics and Electronic Engineering, Henan Institute of Education, Zhengzhou, 450046 (China); Zhang, Jing; Ma, Dongwei [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan, 455000 (China)

2016-09-05

The electronic structure and high thermoelectric properties of Ba{sub 3}Cu{sub 20}Te{sub 13} are studied using first principles calculations and the semiclassical Boltzmann theory. The coexistence of ionic and covalent bonding in Ba{sub 3}Cu{sub 20}Te{sub 13} indicates that it is a Zintl phase compound. The calculated band structure shows that the compound is a semiconductor with an indirect band gap ∼0.45 eV, which is an appropriate band for the high thermoelectric performance. The transport calculations based on the electronic structure indicate that it exhibits relatively large Seebeck coefficients, high electrical conductivities, and high power factor. For Ba{sub 3}Cu{sub 20}Te{sub 13}, the n-type doping may achieve a higher thermoelectric performance than that of p-type doping. It is worth noting that the thermoelectric parameters of Ba{sub 3}Cu{sub 20}Te{sub 13} are comparable or larger than that of Ca{sub 5}Al{sub 2}Sb{sub 6}, a typical Zintl compound representative with high thermoelectric performance. - Highlights: • The electronic structure and thermoelectric(TE) properties are firstly studied. • The heavy and light bands near the Fermi level benefit TE properties. • The comparison indicates Ba{sub 3}Cu{sub 20}Te{sub 13} is a potential high TE material.

Thermoelectric transport properties of BaBiTe{sub 3}-based materials

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

2017-05-15

BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is also reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.

Comparing magnetostructural transitions in Ni{sub 50}Mn{sub 18.75}Cu{sub 6.25}Ga{sub 25} and Ni{sub 49.80}Mn{sub 34.66}In{sub 15.54} Heusler alloys

Energy Technology Data Exchange (ETDEWEB)

Dubenko, Igor [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Granovsky, Alexander [Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Lahderanta, Erkki [Lappeenranta University of Technology, 53851 (Finland); Kashirin, Maxim; Makagonov, Vladimir [Voronezh State Technical University, Voronezh 394026 (Russian Federation); Aryal, Anil; Quetz, Abdiel; Pandey, Sudip [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Rodionov, Igor [Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Samanta, Tapas; Stadler, Shane [Department of Physics & Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Mazumdar, Dipanjan, E-mail: dmazumdar@siu.edu [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Ali, Naushad [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States)

2016-03-01

The crystal structure, magnetic and transport properties, including resistivity and thermopower, of Ni{sub 50}Mn{sub 18.75}Cu{sub 6.25}Ga{sub 25} and Ni{sub 49.80}Mn{sub 34.66}In{sub 15.54} Heusler alloys were studied in the (10–400) K temperature interval. We show that their physical properties are remarkably different, thereby pointing to different origin of their magnetostructural transition (MST). A Seebeck coefficient (S) was found to pass minimum of about −20 µV/K in respect of temperature for both compounds. It was shown that MST observed for both compounds results in jump-like changes in S for Ga-based compound and jump in resistivity of about 20 and 200 µΩ cm for Ga and In –based compounds, respectively. The combined analyzes of the present results with that from literature show that the density of states at the Fermi level does not change strongly at the MST in the case of Ni–Mn–In alloys as compared to that of Ni–Mn–Ga. - Graphical abstract: Temperature dependencies of resistivity for Ni{sub 50}Mn{sub 18.75}Cu{sub 6.25}Ga{sub 25} and Ni{sub 49.80}Mn{sub 34.66}In{sub 15.54} obtained on heating (open symbols) and cooling (closed symbols). Arrows indicate the temperature of direct (T{sub M}) and inverse (T{sub A}) martensitic transitions and ferromagnetic ordering of the austenitic (T{sub C}) and martensitic (T{sub CM}) phases. The T{sub CM}=T{sub A}/T{sub M} in the case of Ga-based alloy. - Highlights: • Magnetostructural transitions (MST) in two compounds with same parent material. • The figure exemplifies how sensitive MST properties are to the density of states. • Proper understanding is required for utilizing these multifunctional materials.

Recuperative dual fuel bruner with low NO{sub x} emissions

Energy Technology Data Exchange (ETDEWEB)

Munko, A.; Kleine Jaeger, F.; Koehne, H. [RWTH Aachen (Germany). Energie- und Stofftransport

2003-07-01

In a current research project of the Arbeitsgemeinschaft Industrieller Forschungsvereinigungen e.V. (AIF) (a German research association) a new dual fuel burner for radiant tubes is being developed at the Department tof Heat and Mass Transfer (EST, RWTH Aachen University). As combustible gas (natural gas type H / Erdgas H) and fuel oil (Heizoel Extra Leicht) are used. These research activities represent the further development of the radiant tube oil burner that was developed on behalf of the AIF and in cooperation with the Forschungsgemeinschaft Industrieofenbau (FOGI e.V.) (AIF project 12345B). The radiant tube burner was designed for the furnace temperature 1000 C can the firing rate 20 to 40 kW. Due to the vaporization of the fuel oil and the homogeneous fuel mixing with a flue gas flow, at the furnace temperature 1000 C and preheated air temperature 850 C NO{sub x}-emissions below 200 mg/m{sup 3} (5% O{sub 2}, Heizoel Extra Leicht) are reached. Using gas (natural gas type H) the burner tests indicate a high NO{sub x}-reduction potential - in gas operation at a lab furnace (furnace temperature 700 C) NO{sub x}-emissions below 40 mg/m{sup 3} result. The future works within the project are the construction of a dual-fuel mixing-device for the alternative use of liquid and gaseous fuel as well as further burner operation tests at furnace temperature 1000 C. (orig.)

Thermoelectric and Transport Properties of N-Type Bi{sub 2−x}Sb{sub x}Te{sub 3−y}Se{sub y} Solid Solutions

Energy Technology Data Exchange (ETDEWEB)

Eum, A-Young; Kim, Il-Ho [Korea National University of Transportation, Chungju (Korea, Republic of)

2017-03-15

Bi{sub 2−x}Sb{sub x}Te{sub 3−y}Se{sub y} (x = 0.1, 0.2 and y = 0.15, 0.3) solid solutions were prepared using encapsulated melting and hot pressing. The lattice constants decreased with increases in the Sb and the Se contents, which revealed the successful formation of solid solutions. The relative densities of the hot-pressed specimens were 95 - 98%. All specimens exhibited n-type conduction at temperatures from 323 K to 523 K, and the electrical conductivity slightly decreased with increasing temperature. With an increase in the Se content, the Seebeck coefficient increased while the electrical and the thermal conductivities decreased; thus, the dimensionless figure of merit could be improved. The maximum dimensionless figure of merit ZT{sub max} = 0.89 was obtained at 423 K for Bi{sub 1.8}Sb{sub 0.2}Te{sub 2.7}Se{sub 0.3}. An increase in the Sb content resulted in a decrease in the lattice thermal conductivity because of an increase in alloy scattering, but its effect on the electrical properties was not superior to the effect of Se substitution. Therefore, Sb substitution could effectively control the thermal properties while Se substitution could effectively control the electrical properties.

An experimental and mathematical modeling study comparing the reactivity and burnout of pulverized coal in air (O{sub 2}/N{sub 2}) and oxyfuel (O{sub 2}/CO{sub 2}) environments

Energy Technology Data Exchange (ETDEWEB)

Liza Elliott; Yinghui Liu; Bart Buhre; Jennifer Martin; Raj Gupta; Terry Wall [University of Newcastle, Callaghan, NSW (Australia). Cooperative Research Centre for Coal in Sustainable Development, Chemical Engineering

2005-07-01

Carbon dioxide in flue gas from conventional combustion processes is present as a dilute gas. CO{sub 2} capture is more easily achieved from a concentrated CO{sub 2} stream, which can be achieved by firing fuels with oxygen to obtain a sequestration ready gas stream, called oxy-fuel combustion. In this technology, the oxygen stream is usually diluted by recycled flue gas (RFG), so that the coal burns in an environment which is primarily O{sub 2}/CO{sub 2}. A size cut of a number of pulverised coals were devolatalised in N{sub 2} and CO{sub 2}. These sized coals were also combusted in a drop-tube furnace in an O{sub 2}/N{sub 2} environment simulating air combustion, and O{sub 2}/CO{sub 2} simulating oxyfuel combustion, with varying O{sub 2} levels from 3 to 30% v/v. Measurements of the extent of devolatilisation and coal burnout were completed. The detailed data provided for one coal indicated that the devolatilisation process in the O{sub 2}/CO{sub 2} environments is influenced by char gasification, and the char reaction rates are fitted better by a fractional order rate than first order in oxygen. Combustion rates in the oxyfuel environment were slightly higher. Estimates of the burnout for furnaces retrofitted from air to oxyfuel indicate that a better burnout can be expected. These trends were common for all coals. 14 refs., 4 figs., 5 tabs.

Local Seebeck coefficient near the boundary in touching Cu/Bi-Te/Cu composites

International Nuclear Information System (INIS)

Yamashita, O.; Odahara, H.

2007-01-01

The thermo-emf ΔV and temperature difference ΔT across the boundary were measured as a function of r for the touching p- and n-type Cu/Bi-Te/Cu composites composed of a combination of t Bi-Te =2.0 mm and t Cu =0.3 mm, where ΔT is produced by imposing a constant voltage of 1.7 V on two Peltier modules connected in series and r is the distance from the boundary that corresponds to the interval s between two thermocouples. The resultant Seebeck coefficient α across the boundary was obtained from the relation α=ΔV/ΔT. As a result, the resultant α of the touching p- and n-type composites have surprisingly great local maximum values of 1330 and -1140 μV/K at r∼0.03 mm, respectively, and decreased rapidly with an increase of r to approach the Seebeck coefficients of the intrinsic Bi-Te compounds. The resultant maximum α of the touching p- and n-type Cu/Bi-Te/Cu composites are approximately 5.4 and 5.5 times higher in absolute value than those of the intrinsic Bi-Te compounds, respectively. It was thus clarified for the first time that the local Seebeck coefficient is enhanced most strongly in the Bi-Te region where there is an approximately 30-μm distance from the boundary, not at the boundary between Bi-Te compounds and copper. (orig.)

Fouling of heat exchanger surfaces by dust particles from flue gases of glass furnaces

Energy Technology Data Exchange (ETDEWEB)

Mutsaers, P.L.M.; Beerkens, R.G.C.; Waal, H. de (Nederlandse Centrale Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek, Delft. Inst. of Applied Physics)

1989-08-01

Fouling by dust particles generally leads to a reduction of the heat transfer and causes corrosion of secondary heat exchangers. A deposition model, including thermodynamic equilibrium calculations, has been derived and applied to describe the deposition (i.e. fouling) process and the nature of the deposition products in a secondary heat exchanger. The deposition model has been verified by means of laboratory experiments, for the case of flue gases from soda-lime glass furnaces. Corrosion of iron-containing metallic materials, caused by the deposition products, has been briefly investigated with the same equipment. There is a close similarity between the experimental results and model calculations. The largest deposition rates from flue gases on cylindrical tubes in cross-flow configuration, are predicted and measured at the upstream stagnation point. The lowest deposition rates are determined at downstream stagnation point locations. At tube surface temperatures of approximately 520 to 550 K, the fouling rate on the tube reaches a maximum. In this temperature region NaHSO{sub 4} is the most important deposition product. This component is mainly formed at temperatures from 470 up to 540 K. The compound Na{sub 3}H(SO{sub 4}){sub 2} seems to be stable up to 570 K, for even higher temperatures Na{sub 2}SO{sub 4} has been found. These deposition products react with iron, SO{sub 3}, oxygen and water vapour forming the complex corrosion product Na{sub 3}Fe(SO{sub 4}){sub 3}. NaHSO{sub 4}, which is formed at tube surface temperatures below 540 K, causes more severe corrosion of iron-containing materials than Na{sub 2}SO{sub 4}. Maintaining temperatures of the heat exchanger surfaces above 550 to 600 K reduces the fouling tendency and corrosion in case of flue gases from oil-fired soda-lime glass furnaces. (orig.).

Detailed model for practical pulverized coal furnaces and gasifiers

Energy Technology Data Exchange (ETDEWEB)

Smith, P.J.; Smoot, L.D.

1989-08-01

This study has been supported by a consortium of nine industrial and governmental sponsors. Work was initiated on May 1, 1985 and completed August 31, 1989. The central objective of this work was to develop, evaluate and apply a practical combustion model for utility boilers, industrial furnaces and gasifiers. Key accomplishments have included: Development of an advanced first-generation, computer model for combustion in three dimensional furnaces; development of a new first generation fouling and slagging submodel; detailed evaluation of an existing NO{sub x} submodel; development and evaluation of an improved radiation submodel; preparation and distribution of a three-volume final report: (a) Volume 1: General Technical Report; (b) Volume 2: PCGC-3 User's Manual; (c) Volume 3: Data Book for Evaluation of Three-Dimensional Combustion Models; and organization of a user's workshop on the three-dimensional code. The furnace computer model developed under this study requires further development before it can be applied generally to all applications; however, it can be used now by specialists for many specific applications, including non-combusting systems and combusting geseous systems. A new combustion center was organized and work was initiated to continue the important research effort initiated by this study. 212 refs., 72 figs., 38 tabs.

Waste and dust utilisation in shaft furnaces

Energy Technology Data Exchange (ETDEWEB)

Senk, D.; Babich, A.; Gudenau, H.W. [Rhein Westfal TH Aachen, Aachen (Germany)

2005-07-01

Wastes and dusts from steel industry, non-ferrous metallurgy and other branches can be utilised e.g. in agglomeration processes (sintering, pelletising or briquetting) and by injection into shaft furnaces. This paper deals with the second way. Combustion and reduction behaviour of iron- and carbon-rich metallurgical dusts and sludges containing lead, zinc and alkali as well as other wastes with and without pulverised coal (PC) has been studied when injecting into shaft furnaces. Following shaft furnaces have been examined: blast furnace, cupola furnace, OxiCup furnace and imperial-smelting furnace. Investigations have been done at laboratory and industrial scale. Some dusts and wastes under certain conditions can be not only reused but can also improve combustion efficiency at the tuyeres as well as furnace performance and productivity.

Alkaline carbonates in blast furnace process

Directory of Open Access Journals (Sweden)

P. Besta

2014-10-01

Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

Industrial furnace with improved heat transfer

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1992-07-07

This patent describes an industrial furnace for heating work which emits volatiles during heating. It comprises a generally cylindrical, closed end furnace section defining a sealable heat transfer chamber for heating work disposed therein; fan means for directing furnace atmosphere as a swirling wind mass about the interior of the furnace section over a portion thereof; heat means for heating the wind mass within the fan chamber; and an incineration track formed as a circumferentially extending groove about the exterior of the furnace section and in heat transfer relationship with and situated at least to extend about a portion of the fan chamber.

A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

Science.gov (United States)

Asadi, R; Ouyang, Z; Mohammd, M M

2015-07-14

We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

Automated, High Temperature Furnace for Glovebox Operation

International Nuclear Information System (INIS)

Neikirk, K.

2001-01-01

The Plutonium Immobilization Project (PIP), to be located at the Savannah River Site SRS, is a combined development and testing effort by Lawrence Livermore National Laboratory (LLNL), Westinghouse Savannah River Company (WSRC), Pacific Northwest National Laboratory (PNNL), Argonne National Laboratory (ANL), and the Australian National Science and Technology Organization (ANSTO). The Plutonium Immobilization process involves the disposition of excess plutonium by incorporation into ceramic pucks. As part of the immobilization process, furnaces are needed for sintering the ceramic pucks. The furnace being developed for puck sintering is an automated, bottom loaded furnace with insulating package and resistance heating elements located within a nuclear glovebox. Other furnaces types considered for the application include retort furnaces and pusher furnaces. This paper, in part, will discuss the furnace technologies considered and furnace technology selected to support reliable puck sintering in a glovebox environment

Characteristics of a Bulk High-Critical Temperature Superconductor Fabricated by the Shock Compaction Method: Possible Use as a Highly Sensitive Magnetic Sensor

Energy Technology Data Exchange (ETDEWEB)

Fujita, H [Interdisci. Grad. School of Sci. and Engi., Grad. School of Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan); Maeji, Y [Interdisci. Grad. School of Sci. and Engi., Grad. School of Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan); Yamagata, K [Relia. Eval. Technol. Center, Nitto Denko Corp., Onomichi, Hiroshima 722-0212 (Japan); Itoh, M [Interdisci. Grad. School of Sci. and Engi., Grad. School of Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan); Kezuka, H [Faculty of Bionics, Tokyo University of Technol., Hachioji, Tokyo 192-0982 (Japan); Kikuchi, M [Kansen Fukushi Research Center, Tohoku Fukushi University Sendai, Miyagi 989-3201 (Japan); Atou, T [Insti. for Mate. Research, Tohoku University Sendai, Miyagi 980-8577 (Japan); Kawasaki, M [Insti. for Mate. Research, Tohoku University Sendai, Miyagi 980-8577 (Japan); Fukuoka, K [Insti. for Mate. Research, Tohoku University Sendai, Miyagi 980-8577 (Japan)

2006-06-01

A magnetic sensor, constructed of bulk Bi-Pb-Sr-Ca-Cu-O (BPSCCO), was fabricated by use of the shock compaction method, employing a propellant gun-system, and then sintered under through use of an electronic furnace. The specimen as a magnetic sensor was maintained in the superconducting state at 77.4 K, under a current density J of approximately 40 A/cm{sup 2} in the absence of an excitation magnetic field B{sub ex}. The superconducting state was then broken and the specimen exposed to a B{sub ex} value of 40x10{sup -4} T. That is, the resistance R{sub meas} of the specimen occurred when exposed to 40x10{sup -4} T under a constant J of 40 A/cm{sup 2}. The magnetic sensitivity S of the specimen was approximately 13 %/(10{sup -4} T) over the range of measurement of the magnetic field B{sub meas} from 0 to {+-}5x10{sup -4} T, under a constant 40x10{sup -4} T for the value of B{sub ex}, being approximately 13 times greater than that of a giant magnetoresistance (GMR) sensor. It was, consequently, determined that it was possible to apply the bulk BPSCCO specimen as a highly sensitive magnetic sensor.

Calculations in furnace technology

CERN Document Server

Davies, Clive; Hopkins, DW; Owen, WS

2013-01-01

Calculations in Furnace Technology presents the theoretical and practical aspects of furnace technology. This book provides information pertinent to the development, application, and efficiency of furnace technology. Organized into eight chapters, this book begins with an overview of the exothermic reactions that occur when carbon, hydrogen, and sulfur are burned to release the energy available in the fuel. This text then evaluates the efficiencies to measure the quantity of fuel used, of flue gases leaving the plant, of air entering, and the heat lost to the surroundings. Other chapters consi

A novel rare earth zinc germanide, Y b{sub 2}Zn{sub 3}Ge{sub 3.1}; crystal structure and physical properties

Energy Technology Data Exchange (ETDEWEB)

Grytsiv, A [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, A-1090 Vienna (Austria); Kaczorowski, D [W Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P-50-950 Wroclaw, PO Box 1410 (Poland); Rogl, P [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringerstrasse 42, A-1090 Vienna (Austria); Tran, V [W Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P-50-950 Wroclaw, PO Box 1410 (Poland); Godart, C [CNRS-UPR209, ISCSA, 2-8 rue Henri Dunant, F94320 Thiais (France); Gofryk, K [W Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P-50-950 Wroclaw, PO Box 1410 (Poland); Giester, G [Institut fuer Mineralogie und Kristallographie, Universitaet Wien, Althanstrasse 14, A-1090 Vienna (Austria)

2005-01-19

A novel ternary structure type has been determined from single crystals of Y b{sub 2}Zn{sub 3}Ge{sub 3.1} grownfrom zinc flux solvent. Y b{sub 2}Zn{sub 3}Ge{sub 3.1} crystallizes in a novel monoclinic structure type (a = 1.5804(2) nm, b 0.429 70(1) nm, c = 1.1524(1) nm; {beta} = 126.14(1) deg.) with space group C 2/m,Z = 4. The large ytterbium atoms are at the centres of pentagonal pyramids formed by Zn/Ge atoms. Zinc atoms are centred in distorted triangular prisms and polyhedra around germanium atoms are related to octahedra. The void at the centre of the Zn octahedra is only partially (20%) filled by Ge atoms. There are two positions for Yb atoms in the unit cell, which contain ions with valency slightly higher than 2+, as evidenced by x-ray absorption spectroscopy and bulk magnetic measurements. The compound exhibits metallic-like electrical conductivity, and its Seebeck coefficient shows a temperature variation characteristic of metals, being, however, fairly enhanced, as expected for intermediate valence systems.

Determining a hopping polaron's bandwidth from its Seebeck coefficient: Measuring the disorder energy of a non-crystalline semiconductor

International Nuclear Information System (INIS)

Emin, David

2016-01-01

Charge carriers that execute multi-phonon hopping generally interact strongly enough with phonons to form polarons. A polaron's sluggish motion is linked to slowly shifting atomic displacements that severely reduce the intrinsic width of its transport band. Here a means to estimate hopping polarons' bandwidths from Seebeck-coefficient measurements is described. The magnitudes of semiconductors' Seebeck coefficients are usually quite large (>k/|q| = 86 μV/K) near room temperature. However, in accord with the third law of thermodynamics, Seebeck coefficients must vanish at absolute zero. Here, the transition of the Seebeck coefficient of hopping polarons to its low-temperature regime is investigated. The temperature and sharpness of this transition depend on the concentration of carriers and on the width of their transport band. This feature provides a means of estimating the width of a polaron's transport band. Since the intrinsic broadening of polaron bands is very small, less than the characteristic phonon energy, the net widths of polaron transport bands in disordered semiconductors approach the energetic disorder experienced by their hopping carriers, their disorder energy

Optimization of electrodeposited p-doped Sb{sub 2}Te{sub 3} thermoelectric films by millisecond potentiostatic pulses

Energy Technology Data Exchange (ETDEWEB)

Schumacher, Christian; Akinsinde, Lewis; Zastrow, Sebastian; Heiderich, Sonja; Toellner, William; Nielsch, Kornelius; Bachmann, Julien [Institute of Applied Physics, University of Hamburg, Jungiusstrasse 11, 20355 Hamburg (Germany); Reinsberg, Klaus G.; Broekaert, Jose A.C. [Institute of Applied and Inorganic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Rampelberg, Geert; Detavernier, Christophe [Department of Solid State Sciences, University of Ghent, Krijgslaan 281/S1, 9000 Ghent (Belgium)

2012-03-15

A systematic optimization of p-type Sb{sub 2}Te{sub 3} thermoelectric films made by potentiostatic electrodeposition on Au and stainless steel substrates is presented. The influence of the preparative parameters of deposition voltage, concentration, and the deposition method are investigated in a nitric acid solution. As a postdeposition step, the influence of annealing the films is investigated. The use of a potential-controlled millisecond-pulsed deposition method could improve both the morphology and the composition of the films. The samples are characterized in terms of composition, crystallinity, Seebeck coefficient, and electrical resistivity. Pulsed-deposited films exhibit Seebeck coefficients of up to 160 {mu}V K{sup -1} and an electrical conductivity of 280 S cm{sup -1} at room temperature, resulting in power factors of about 700 {mu}W m{sup -1} K{sup -2}. After annealing, power factors of maximum 852 {mu}W m{sup -1} K{sup -2} are achieved. Although the annealing of DC-deposited films significantly increased the power factor, they do not reach the values of the pulsed-deposited films in the preannealing state. Structural analysis is performed with X-ray diffraction and shows the crystalline structure of Sb{sub 2}Te{sub 3} films. The performance is tuned by annealing of deposited films up to 300 C under He atmosphere while performing in-situ X-ray diffraction and resistivity measurements. The chemical analysis of the films is performed by inductively coupled plasma optical emission spectroscopy (ICP-OES) as well as scanning electron microscope energy dispersive X-ray analysis (SEM-EDX). (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Electrostatic Levitation Furnace for the ISS

Science.gov (United States)

Murakami, Keiji; Koshikawa, Naokiyo; Shibasaki, Kohichi; Ishikawa, Takehiko; Okada, Junpei; Takada, Tetsuya; Arai, Tatsuya; Fujino, Naoki; Yamaura, Yukiko

2012-01-01

JAXA (Japan Aerospace Exploration Agency) has just started the development of Electrostatic Levitation Furnace to be launched in 2014 for the ISS. This furnace can control the sample position with electrostatic force and heat it above 2000 degree Celsius using semiconductor laser from four different directions. The announcement of Opportunity will be issued soon for this furnace. In this paper, we will show the specifications of this furnace and also the development schedule

Effects of forming temperature and sintering rate to the final properties of FeCuAl powder compacts formed through uniaxial die compaction process

Science.gov (United States)

Rahman, M. M.; Ismail, M. A.; Sopyan, I.; Rahman, H. Y.

2018-01-01

This paper presents the outcomes of an experimental investigation on the effects of forming temperature and sintering schedule to the final characteristics of FeCuAl powder mass formed at different temperature and sintered at different schedule. A lab-scale uni-axial die compaction rig was designed and fabricated which enabled the compaction of powder mass at room temperature as well as elevated temperature. Iron (Fe) powder ASC 100.29 was mechanically mixed with other elemental powders, namely copper (Cu), and aluminum (Al) for 60 minutes and compacted at three different temperature, i.e., 30°C, 150°C, and 200°C by applying 425 MPa of simultaneous downward and upward axial loading to generate green compacts. The as-pressed samples were inspected visually and the defect-free green compacts were subsequently sintered in an argon gas fired furnace at 800°C for 60 min at three different heating/cooling rates, i.e., 5, 10, and 15°C/min, respectively. The sintered samples were then characterised for their physical, electrical, and mechanical properties. The microstructures of the sintered samples were also analysed. The results revealed that a forming temperature of 150°C and a sintering rate of 10°C/min could produce a product with better characteristics.

The effect of structural vacancies on the thermoelectric properties of (Cu₂Te){sub 1–x}(Ga₂Te₃)<sub>x>

Energy Technology Data Exchange (ETDEWEB)

Ye, Zuxin; Young Cho, Jung; Tessema, Misle M. [Optimal Inc., Plymouth Township, MI 48170 (United States); Salvador, James R., E-mail: james.salvador@gm.com [GM Global R and D, Warren, MI 48090 (United States); Waldo, Richard A. [GM Global R and D, Warren, MI 48090 (United States); Wang, Hsin; Cai, Wei [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2013-05-01

We have studied the effects of structural vacancies on the thermoelectric properties of the ternary compounds (Cu₂Te)<sub>1–xsub>(Ga₂Te₃)<sub>x> (x=0.5, 0.55, 0.571, 0.6, 0.625, 0.667 and 0.75), which are solid solutions found in the pseudo-binary phase diagram for Cu₂Te and Ga₂Te₃, and possesses tunable structural vacancy concentrations. This materials system is not suitable due to the cost and scarcity of the constituent elements, but the vacancy behavior is well understood and will provide a valuable test case for other systems more suitable from the standpoint of cost and abundance of raw materials, which also possesses these vacancy features, but whose structural characterization is lacking at this stage. We find that the nominally defect free phase CuGaTe₂ possess the highest ZT (ZT=S²T/ρκ, where S is the Seebeck coefficient and ρ is the electrical resistivity κ is the thermal conductivity and T is the absolute temperature) which approaches 1 at 840 K and seems to continuously increase above this temperature. This result is due to the unexpectedly low thermal conductivity found for this material at high temperature. The low thermal conductivity was caused by strong Umklapp (thermally resistive scattering processes involving three phonons) phonon scattering. We find that due to the coincidentally strong scattering of carriers by the structural defects that higher concentrations of these features lead to poor electrical transport properties and decreased ZT. - Graphical abstract: Thermal conductivity and zT as a function of temperature for a series of compounds of the type (Cu₂Te)_{1–xsub>(Ga₂Te₃)x (x=0.5, 0.55, 0.571, 0.6, 0.625, 0.667 and 0.75). Highlights: • All the samples show p-type semiconducting behavior in the temperature dependence of the Seebeck and Hall coefficients. • The increased carrier concentration and the introduction of vacancies diminish the carrier mobility and power factor. • The low}

Electrical and materials properties of AlN/ HfO{sub 2} high-k stack with a metal gate

Energy Technology Data Exchange (ETDEWEB)

Reid, Kimberly G. [Tokyo Electron U.S., 14338 FM 1826, Austin, TX 78737 (United States)], E-mail: kim@ireid.com; Dip, Anthony [Tokyo Electron U.S., 2400 Grove Blvd., Austin, TX 78747 (United States)], E-mail: anthony.dip@us.tel.com; Sasaki, Sadao [Tokyo Electron U.S. (United States)], E-mail: Sadao.sasaki@us.tel.com; Triyoso, Dina [Freescale Semiconductor Inc., 3501 Ed Bluestein Blvd, Austin, TX 78721 (United States)], E-mail: Dina.Triyoso@freescale.com; Samavedam, Sri [Freescale Semiconductor Inc., 3501 Ed Bluestein Blvd, Austin, TX 78721 (United States)], E-mail: Sri.Samavedam@freescale.com; Gilmer, David [SEMATECH 2706 Montopolis Drive, Austin, TX 78741 (United States)], E-mail: David.Gilmer@sematech.org; Gondran, Carolyn F.H. [Process Characterization Laboratory, ATDF/SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741 (United States)], E-mail: Carolyn.Gondran@atdf.com

2009-02-27

In this study, aluminum nitride (AlN) was grown by molecular layer deposition on HfO{sub 2} that had been deposited on 200 mm Si (100) substrates. The AlN was grown on HfO{sub 2} using sequential exposures of trimethyl-aluminum and ammonia (NH{sub 3}) in a batch vertical furnace. Excellent thickness uniformity on test wafers from the top of the furnace to the bottom of the furnace (across the furnace load) was obtained. The equivalent oxide thickness was 16.5-18.8 A for the AlN/HfO{sub 2} stack on patterned device wafers with a molybdenum oxynitride metal gate with leakage current densities from low 10{sup -5} to mid 10{sup -6} A/cm{sup 2} at threshold voltage minus one volt. There was no change in the work function with the AlN cap on HfO{sub 2} with the MoN metal gate, even with a 1000 deg. C anneal.

Crack arrest toughness of structural steels evaluated by compact test

International Nuclear Information System (INIS)

Nakano, Yoshifumi; Tanaka, Michihiro

1982-01-01

Crack arrest tests such as compact, ESSO and DCB tests were made on SA533B Cl. 1, HT80 and KD32 steels to evaluate the crack arrest toughness. The main results obtained are as follows: (1) The crack arrest toughness could be evaluated by K sub(Ia) which was obtained by the static analysis of compact test. (2) K sub(ID) determined by the dynamic analysis of compact test was greater than K sub(Ia), though K sub(ID) became close to K sub(Ia)/K sub(Q) became a unity where K sub(Q) is the stress intensity factor at the crack initiation. (3) No significant difference was observed between K sub(Ia) and K sub(ca) obtained by ESSO and DCB tests, though K sub(ca) obtained by DCB test tended to be smaller than K sub(Ia) at lower temperatures. (4) K sub(Ia) was smaller than K sub(Ic) in the transition temperature range, while it was greater than K sub(Id). In the temperature range where K sub(Ic), which was determined from J sub(Ic), decreased with temperature increase, however, it was smaller than K sub(Ia). (5) The fracture appearance transition temperature and the absorbed energy obtained by 2 mm V-notch Charpy test were appropriate parameters for representing the crack arrest toughness, while the NDT temperature was not. (author)

Thermoelectric properties of c-GeSb{sub 0.75}Te{sub 0.5} to h-GeSbTe{sub 0.5} thin films through annealing treatment effects

Energy Technology Data Exchange (ETDEWEB)

Vora-ud, Athorn, E-mail: athornvora-ud@snru.ac.th [Program of Physics, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Mueang District, Sakon Nakhon 47000 (Thailand); Thermoelectrics Research Center, Research and Development Institution, Sakon Nakhon Rajabhat University, Mueang District, Sakon Nakhon 47000 (Thailand); Horprathum, Mati, E-mail: mati.horprathum@nectec.or.th [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Eiamchai, Pitak [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Muthitamongkol, Pennapa; Chayasombat, Bralee; Thanachayanont, Chanchana [National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Pankiew, Apirak [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Klamchuen, Annop [National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Naenkieng, Daengdech; Plirdpring, Theerayuth; Harnwunggmoung, Adul [Thermoelectric and Nanotechnology Research Center, Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Huntra Phranakhon, Si Ayutthaya 13000 (Thailand); Charoenphakdee, Anek [NANO-Thermoelectrics Research Center, Division of Applied Physics, Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Mueng Nakorn Ratchasima 30000 Thailand (Thailand); Somkhunthot, Weerasak [Program of Physics, Faculty of Science and Technology, Loei Rajabhat University, Muang District, Loei 42000 (Thailand); and others

2015-11-15

Germanium–Antimony–Tellurium (Ge–Sb–Te) thin films were deposited on silicon wafers with 1-μm silicon dioxide (SiO{sub 2}/Si) by pulsed dc magnetron sputtering from a 99.99% GeSbTe target of 1:1:1 ratio at ambient temperature. The samples were annealed at 573, 623, 673, and 723 K for 3600 s in a vacuum state. The effects of the annealing treatment on phase identification, atomic composition, morphology and film thickness, carrier concentration, mobility, and Seebeck coefficient of the Ge–Sb–Te samples have been investigated by grazing-incidence X-ray diffraction, auger electron spectroscopy, field-emission scanning electron microscopy, Hall-effect measurements, and steady state method, respectively. The results demonstrated that the as-deposited Ge–Sb–Te sample was amorphous. Atomic composition of as-deposited and annealed films at 573 K and 623 K were GeSb{sub 0.75}Te{sub 0.5} while annealed films at 673 K and 723 K were GeSbTe{sub 0.5} due to Sb-rich GeSb{sub 0.75}Te{sub 0.5}. The samples annealed at 573 K and 623 K showed the crystal phases of cubic structure (c-GeSb{sub 0.75}Te{sub 0.5}) into hexagonal structure (h-GeSbTe{sub 0.5}) after annealing at 673 K and 723 K. The study demonstrated the insulating condition from the as-deposited GeSbTe film, and the changes towards the thermoelectric properties from the annealing treatments. The GeSbTe films annealed at 673 K yielded excellent thermoelectric properties with the electrical resistivity, Seebeck coefficient, and power factor at approximately 1.45 × 10{sup −5} Ωm, 71.07 μV K{sup −1}, and 3.48 × 10{sup −4} W m{sup −1} K{sup −2}, respectively. - Highlights: • GeSbTe thin films were successfully sputtered for thermoelectric properties. • GeSbTe films were examined among physical, electrical and thermoelectric properties. • Thermoelectric properties were discussed based on composition of the films.

DC conductivity and Seebeck coefficient of nonstoichiometric MgCuZn ferrites

Directory of Open Access Journals (Sweden)

Madhuri W.

2017-02-01

Full Text Available Nonstoichiometric series of Mg0.5−xCuxZn0.5Fe1.9O4−δ where x = 0.0, 0.1, 0.15, 0.2 and 0.25 has been synthesized by conventional solid state reaction route. The single phase spinel structure of the double sintered ferrites was confirmed by X-ray diffraction patterns (XRD. The ferrite series was studied in terms of DC electrical conductivity and thermoelectric power in the temperature ranging from room temperature to 300 °C and 400 °C, respectively. It was observed that DC electrical conductivity and Seebeck coefficient α decreased with the increase in x. DC electrical conductivity was found to decrease by about 4 orders. All the compositions showed a negative Seebeck coefficient exhibiting n-type semiconducting nature. From the above experimental results, activation energy and mobility of all the samples were estimated. Small polaron hopping conduction mechanism was suggested for the series of ferrites. Owing to their low conductivity the nonstoichiometric MgCuZn ferrites are the best materials for transformer core and high definition television deflection yokes.

Investigation of electronic, magnetic and thermoelectric properties of Zr{sub 2}NiZ (Z = Al,Ga) ferromagnets

Energy Technology Data Exchange (ETDEWEB)

Yousuf, Saleem, E-mail: nengroosaleem17@gmail.com; Gupta, Dinesh C., E-mail: sosfizix@gmail.com

2017-05-01

Systematic investigation of impact of electronic structure and magnetism, on the thermoelectric properties of new Zr{sub 2}NiZ (Z = Al, Ga) Heusler alloys are determined using density functional theory calculations. Half-metallicity with ferromagnetic character is supported by their 100% spin polarizations at the Fermi level. Magnetic moment of ∼3 μ{sub B} is according to the Slater-Puling rule, enables their practical applications. Electron density plots are used to analyse the nature of bonding and chemical composition. Boltzmann's theory is conveniently employed to investigate the thermoelectric properties of these compounds. The analysis of the thermal transport properties specifies the Seebeck coefficient as 25.6 μV/K and 18.6 μV/K at room temperature for Zr{sub 2}NiAl and Zr{sub 2}NiGa, respectively. The half-metallic nature with efficient thermoelectric coefficients suggests the likelihood of these materials to have application in designing spintronic devices and imminent thermoelectric materials. - Highlights: • The compounds are half-metallic ferromagnets. • 100% spin-polarized compounds for spintronics. • Increasing Seebeck coefficient over a wide temperature range. • Zr{sub 2}NiAl is efficient thermoelectric material than Zr{sub 2}NiGa.

Effect of microwave-assisted sintering on dielectric properties of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramic

Energy Technology Data Exchange (ETDEWEB)

Rani, Suman, E-mail: sumanranigju@gmail.com; Ahlawat, Neetu; Punia, R.; Kundu, R. S. [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hissar 125001, Haryana (India); Ahlawat, N. [Matu Ram Institute of Engineering and Management, Rohtak (India)

2016-05-23

In this present work, CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) was synthesized by conventional solid-state reaction technique. The synthesis process was carried out in two phases; by conventional process (calcination and sintering at 1080°C for 10 hours) and phase II involves the micro assisted pre sintering of conventionally calcined CCTO for very short soaking time of 30 min at 1080°C in a microwave furnace followed by sintering at 1080°C for 10 hours in conventional furnace. X-ray diffraction (XRD) patterns confirmed the formation of single phase ceramic. Dielectric properties were studied over the frequency range from 50Hz -5MHz at temperatures (273K-343K). It was observed that pre- microwave sintering enhance the dielectric constant values from 10900 to 11893 and respectively reduces the dielectric loss values from 0.49 to 0.34 at room temperature(1 KHz). CCTO ceramics which are found desirable for many technological applications. The effect is more pronounced at low frequencies of applied electric field.

Thermoelectric properties of p-type Ag{sub 1−x}(Pb{sub 1−y}Sn{sub y}){sub m}Sb{sub 1−z}Te{sub m+2}

Energy Technology Data Exchange (ETDEWEB)

Ahn, Kyunghan [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Center for Nanoparticle Research, Institute for Basic Science, (IBS), Seoul 151-742 (Korea, Republic of); Kong, Huijun; Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Kanatzidis, Mercouri G., E-mail: m-kanatzidis@northwestern.edu [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)

2016-10-15

The thermoelectric properties of Ag{sub 1−x}(Pb{sub 1−y}Sn{sub y}){sub m}Sb{sub 1−z}Te{sub m+2} (4≤m≤16, −0.1≤x≤0.3, 1/3≤y≤2/3, 0.2≤z≤0.4; Lead Antimony Silver Tellurium Tin, LASTT-m) compositions were investigated in the temperature range of 300 to ~670 K. All samples crystallize in the average NaCl-type structure without any noticeable second phase and exhibit very narrow bandgaps of <0.1 eV. We studied a range of m values, silver concentrations (x), Pb/Sn ratios (y), and antimony concentrations (z) to determine their effects on the thermoelectric properties. The samples were investigated as melt grown polycrystalline ingots. Varying the Ag contents, the Pb/Sn ratios, and the Sb contents off-stoichiometry allowed us to control the electrical conductivity, the Seebeck coefficient, and the thermal conductivity. The electrical conductivity tends to decrease with decreasing m values. The highest ZT of ~1.1 was achieved at ~660 K for Ag{sub 0.9}Pb{sub 5}Sn{sub 5}Sb{sub 0.8}Te{sub 12} mainly due to the very low lattice thermal conductivity of ~0.4 W/(m K) around 660 K. Also, samples with charge-balanced stoichiometries, Ag(Pb{sub 1−y}Sn{sub y}){sub m}SbTe{sub m+2}, were studied and found to exhibit a lower power factor and higher lattice thermal conductivity than the Ag{sub 1−x}(Pb{sub 1−y}Sn{sub y}){sub m}Sb{sub 1−z}Te{sub m+2} compositions. - Graphical abstract: The Ag{sub 1−x}(Pb{sub 1−y}Sn{sub y}){sub m}Sb{sub 1−z}Te{sub m+2} system defines a complex and flexible class of tunable thermoelectric class of materials with high performance.

Two superstructures of Ce{sub 3}Rh{sub 4}Ge{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Vosswinkel, Daniel; Hoffmann, Rolf-Dieter [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Svitlyk, Volodymyr [European Synchrotron Radiation Facility, Grenoble (France); and others

2018-04-01

Two different samples of Ce{sub 3}Rh{sub 4}Ge{sub 4} were synthesized from different starting compositions by melting of the elements in an arc-melting furnace followed by annealing sequences in a sealed tantalum ampoule in a muffle furnace. The structures of two different stacking variants were refined on the basis of temperature dependent single-crystal X-ray diffractometer data. At high temperature Ce{sub 3}Rh{sub 4}Ge{sub 4} adopts the U{sub 3}Ni{sub 4}Si{sub 4} type structure with strongly enhanced anisotropic displacement parameters for the Rh1 atoms. For the two different crystals, additional reflections start to appear at different temperatures. The first crystal showed additional reflections already at room temperature (stacking variant I) and the second one showed additional reflections emerging below 270 K (stacking variant II). Stacking variant I could be described with the (3+1)D superspace group I2/m(α0γ)00; α=1/2a*, γ=1/2c*; (Z=2), 1252 F{sup 2} values, 48 variables, wR=0.0306 for the main and wR=0.0527 for 440 1{sup st} order satellite reflections, similar to Pr{sub 3}Rh{sub 4}Ge{sub 4}. For stacking variant II the (3+1)D superspace group is Immm(α00)00s; α=1/2a*; (Z=2). The structure could be refined with 1261 F{sup 2} values, 53 variables and residuals of wR=0.0331 for the main reflections and wR=0.1755 (R1{sub obs}=0.0788) for the 1{sup st} order satellite reflections, [a=406.2(1), b=423.7(1) and c=2497.1(1) pm]. The commensurate description could be transformed to a three-dimensional (3D) supercell with space group Pnma and Z=4: a=812.5(1), b=423.7(1), c=2497.1(2) pm, 1261 F{sup 2} values, 69 variables and wR=0.0525. The relation of the U{sub 3}Ni{sub 4}Si{sub 4} type structure, the (3+1)D modulated and the 3D supercells are discussed on the basis of group-subgroup schemes. Ab initio electronic structure calculations are in line with the diffraction experiments, revealing the lowest total energy for the Pnma phase.

Automated, High Temperature Furnace for Glovebox Operation

International Nuclear Information System (INIS)

Neikirk, K.

2001-01-01

The U.S. Department of Energy will immobilize excess plutonium in the proposed Plutonium Immobilization Plant (PIP) at the Savannah River Site (SRS) as part of a two track approach for the disposition of weapons usable plutonium. As such, the Department of Energy is funding a development and testing effort for the PIP. This effort is being performed jointly by Lawrence Livermore National Laboratory (LLNL), Westinghouse Savannah River Company (WSRC), Pacific Northwest National Laboratory (PNNL), and Argonne National Laboratory (ANL). The Plutonium Immobilization process involves the disposition of excess plutonium by incorporation into ceramic pucks. As part of the immobilization process, furnaces are needed for sintering the ceramic pucks. The furnace being developed for puck sintering is an automated, bottom loaded furnace with insulting package and resistance heating elements located within a nuclear glovebox. Other furnaces considered for the application include retort furnaces and pusher furnaces. This paper, in part, will discuss the furnace technologies considered and furnace technology selected to support reliable puck sintering in a glovebox environment. Due to the radiation levels and contamination associated with the plutonium material, the sintering process will be fully automated and contained within nuclear material gloveboxes. As such, the furnace currently under development incorporates water and air cooling to minimize heat load to the glovebox. This paper will describe the furnace equipment and systems needed to employ a fully automated puck sintering process within nuclear gloveboxes as part of the Plutonium Immobilization Plant

Synthesis and structure of Sr{sub 2}Pd{sub 2}In and Sr{sub 2}Pt{sub 2}In

Energy Technology Data Exchange (ETDEWEB)

Muts, I. [Inst. fuer Anorganische und Analytische Chemie, Univ. Muenster (Germany); Inorganic Chemistry Dept., Ivan Franko National Univ. of Lviv (Ukraine); Nilges, T.; Rodewald, U.C.; Poettgen, R. [Inst. fuer Anorganische und Analytische Chemie, Univ. Muenster (Germany); Zaremba, V.I. [Inorganic Chemistry Dept., Ivan Franko National Univ. of Lviv (Ukraine)

2007-12-15

The new intermetallic compounds Sr{sub 2}Pd{sub 2}In and Sr{sub 2}Pt{sub 2}In were synthesized from the elements in sealed tantalum tubes in a water-cooled sample chamber of an induction furnace. Both indides crystallize with the HT-Pr{sub 2}Co{sub 2}Al-type structure: C2/c, a = 1048.7(2), b = 603.5(2), c = 830.6(1) pm. {beta} = 103.68(2) , wR2 = 0.0492, 743 F{sup 2} values for Sr{sub 2}Pd{sub 2}In; a = 1026.8(2), b = 599.0(1), c = 830.3(2) pm, {beta} = 103.17(1) , wR2 = 0.0666, 885 F{sup 2} values for Sr{sub 2}Pt{sub 2}In with 25 variables per refinement. The shortest interatomic distances occur for the Pd-In (Pt-In) and Pd-Pd (Pt-Pt) contacts. The strontium atoms are embedded in complex three-dimensional polyanionic networks of compositions [Pd{sub 2}In] and [Pt{sub 2}In]. (orig.)

Magnetic and bioactivity evaluation of ferrimagnetic ZnFe{sub 2}O{sub 4} containing glass ceramics for the hyperthermia treatment of cancer

Energy Technology Data Exchange (ETDEWEB)

Shah, Saqlain A., E-mail: saqlain007pk@hotmail.co [Biomaterials Lab, Department of Physics, GC University Lahore (Pakistan); Hashmi, M.U. [Biomaterials Lab, Department of Physics, GC University Lahore (Pakistan); Alam, S. [PITMAEM, PCSIR Lahore (Pakistan); Shamim, A. [Biomaterials Lab, Department of Physics, GC University Lahore (Pakistan)

2010-02-15

Glass ceramics of the composition xZnO.25Fe{sub 2}O{sub 3}.(40-x)SiO{sub 2}.25CaO.7P{sub 2}O{sub 5}.3Na{sub 2}O were prepared by the melt-quench method using oxy-acetylene flame. Glass-powder compacts were sintered at 1100 deg. C for 3 h and then rapidly cooled at -10 deg. C. X-ray diffraction (XRD) revealed 3 prominent crystalline phases: ZnFe{sub 2}O{sub 4}, CaSiO{sub 3} and Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}. Vibrating sample magnetometer (VSM) data at 10 KOe and 500 Oe showed that saturation magnetization, coercivity and hence hysteresis area increased with the increase in ZnO content. Nano-sized ZnFe{sub 2}O{sub 4} crystallites were of pseudo-single domain structure and thus coercivity increased with the increase in crystallite size. ZnFe{sub 2}O{sub 4} exhibited ferrimagnetism due to the random distribution of Zn{sup 2+} and Fe{sup 3+} cations at tetrahedral A sites and octahedral B sites. This inversion/random distribution of cations was probably due to the surface effects of nano-ZnFe{sub 2}O{sub 4} and rapid cooling of the material from 1100 deg. C (thus preserving the high temperature state of the random distribution of cations). Calorimetric measurements were carried out using magnetic induction furnace at 500 Oe magnetic field and 400 KHz frequency. The data showed that maximum specific power loss and temperature increase after 2 min were 26 W/g and 37 deg. C, respectively for the sample containing 10% ZnO. The samples were immersed in simulated body fluid (SBF) for 3 weeks. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDX) and XRD results confirmed the growth of precipitated hydroxyapatite phase after immersion in SBF, suggesting that the ferrimagnetic glass ceramics were bioactive and could bond to the living tissues in physiological environment.

Improved Casting Furnace Conceptual Design

Energy Technology Data Exchange (ETDEWEB)

Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tolman, David Donald [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-02-01

In an attempt to ensure more consistent casting results and remove some schedule variance associated with casting, an improved casting furnace concept has been developed. The improved furnace uses the existing arc melter hardware and glovebox utilities. The furnace concept was designed around physical and operational requirements such as; a charge sized of less than 30 grams, high heating rates and minimal additional footprint. The conceptual model is shown in the report as well as a summary of how the requirements were met.

Experimental and theoretical study of transport properties in uniaxially pressed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+d}elta ceramic samples

Energy Technology Data Exchange (ETDEWEB)

Garcia-Fornaris, I. [Departamento de Ciencias Basicas, Universidad de Granma, Apdo. 21, P.O. Box 85100, Bayamo (Cuba); Mune, P. [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Suzuki, P.A. [Escola de Engenharia de Lorena, Universidade de Sao Paulo, 12602-810 Lorena, SP (Brazil); Alberteris-Campos, M. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, 05508-900 Sao Paulo, SP (Brazil); Jardim, R.F. [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 S. Paulo, SP (Brazil); Govea-Alcaide, E., E-mail: malvareza@udg.co.c [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, 05508-900 Sao Paulo, SP (Brazil)

2010-02-15

Experimental and theoretical studies on the magnetic field dependence of the electrical resistance R(B{sub a}) and the transport noise (TN) in polycrystalline high-T{sub c} superconductors subjected to different uniaxial compacting pressures were conducted. X-ray diffraction rocking curves were performed in different surfaces of the samples in order to investigated the degree of texture. The results indicated an improvement of the degree of texture with increasing the uniaxial compacting pressure. In theoretical simulations of the data, the polycrystalline superconductors were described as a series-parallel array of Josephson devices. The intergranular magnetic field is described within the framework of the intragranular flux-trapping model and the distribution of the grain-boundary angles is assumed to follow the Rayleigh statistical function. The proposed model describes well the experimental magnetoresistance R(B{sub a}) data. We have found that the behavior of the R(B{sub a}) curves changes appreciably when different uniaxially compacting pressures are applied to the sample and such a changes are reproduced by the model when different grain-boundary angles distributions are used. In addition, changes in the R(B{sub a}) dependence have their counterparts in the experimental transport noise signals.

Industrial and process furnaces principles, design and operation

CERN Document Server

Jenkins, Barrie

2014-01-01

Furnaces sit at the core of all branches of manufacture and industry, so it is vital that these are designed and operated safely and effi-ciently. This reference provides all of the furnace theory needed to ensure that this can be executed successfully on an industrial scale. Industrial and Process Furnaces: Principles, 2nd Edition provides comprehensive coverage of all aspects of furnace operation and design, including topics essential for process engineers and operators to better understand furnaces. This includes: the combustion process and its control, furnace fuels, efficiency,

Behavior of coke in large blast furnaces

Energy Technology Data Exchange (ETDEWEB)

Nakamura, N

1978-01-01

Three blast furnaces were quenched in operation and the contents were examined; the temperature distribution was also measured, using Tempil pellets. The furnaces examined included a low productivity one, which was examined to see what was wrong. Changes in the quality of coke as it descends in the furnace, and coke behavior in the raceway and hearth are reported. The functions required of coke, and the effects of poor coke quality, are explained, together with the coke quality required in large blast furnaces. A theoretical study of the role of coke in large blast furnaces is included.

Microstructural morphologies of slag based glass-ceramics nucleated with 5 wt% Cr{sub 2}O{sub 3} and 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Oevecoglu, M.L.; Oezkal, B. [Istanbul Technical Univ. (Turkey). Dept. of Metallurgical and Materials Enginering; Catakli, E. [Mimar Sinan Univ., Istanbul (Turkey). Faculty of Science and Literature; Erkmen, Z.E. [Istnabul Univ. (Turkey). Dept. of Metallurgical Engineering

2002-07-01

Glass-ceramic materials were developed from the blast-furnace slags by mixing 5 wt% Cr{sub 2}O{sub 3} and 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2}. The samples were nucleated for 18 h at 780 C and crystallized for 20 min. at 905 C, respectively. SEM and SEM/EDS investigations revealed the presence of clover-shaped TiO{sub 2} particles in the glassy matrix of the sample nucleated with 5 wt% Cr{sub 2}O{sub 3} + 5 wt% TiO{sub 2} and polygonal-shaped Cr{sub 2}O{sub 3} platelets for both samples. XRD scans revealed the presence of akermanite (2CaO.MgO.2SiO{sub 2}) and gehlenite (2CaO.Al{sub 2}O{sub 3}.SiO{sub 2}) peaks indicating the existence of the mellilite solid solution for the crystallized glass-ceramic samples. (orig.)

Spin Seebeck effect in Y-type hexagonal ferrite thin films

Czech Academy of Sciences Publication Activity Database

Hirschner, Jan; Maryško, Miroslav; Hejtmánek, Jiří; Uhrecký, Róbert; Soroka, Miroslav; Buršík, Josef; Anadón, P.; Aguirre, M.H.; Knížek, Karel

2017-01-01

Roč. 96, č. 6 (2017), s. 1-8, č. článku 064428. ISSN 2469-9950 R&D Projects: GA ČR(CZ) GA14-18392S Institutional support: RVO:68378271 ; RVO:61388980 Keywords : hexagonal ferrites * spin Seebeck effect * thin films * magnetization * ferrimagnetic ferrites Subject RIV: BM - Solid Matter Physics ; Magnetism; CA - Inorganic Chemistry (UACH-T) OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.); Inorganic and nuclear chemistry (UACH-T) Impact factor: 3.836, year: 2016

Compaction shock dissipation in low density granular explosive

Energy Technology Data Exchange (ETDEWEB)

Rao, Pratap T.; Gonthier, Keith A., E-mail: gonthier@me.lsu.edu; Chakravarthy, Sunada [Mechanical and Industrial Engineering Department, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

2016-06-14

The microstructure of granular explosives can affect dissipative heating within compaction shocks that can trigger combustion and initiate detonation. Because initiation occurs over distances that are much larger than the mean particle size, homogenized (macroscale) theories are often used to describe local thermodynamic states within and behind shocks that are regarded as the average manifestation of thermodynamic fields at the particle scale. In this paper, mesoscale modeling and simulation are used to examine how the initial packing density of granular HMX (C{sub 4}H{sub 8}N{sub 8}O{sub 8}) C{sub 4}H{sub 8}N{sub 8}O{sub 8} having a narrow particle size distribution influences dissipation within resolved, planar compaction shocks. The model tracks the evolution of thermomechanical fields within large ensembles of particles due to pore collapse. Effective shock profiles, obtained by averaging mesoscale fields over space and time, are compared with those given by an independent macroscale compaction theory that predicts the variation in effective thermomechanical fields within shocks due to an imbalance between the solid pressure and a configurational stress. Reducing packing density is shown to reduce the dissipation rate within shocks but increase the integrated dissipated work over shock rise times, which is indicative of enhanced sensitivity. In all cases, dissipated work is related to shock pressure by a density-dependent power law, and shock rise time is related to pressure by a power law having an exponent of negative one.

Experimental study of the anisotropic magneto-Seebeck effect in (Ga,Mn)As thin films

Energy Technology Data Exchange (ETDEWEB)

Althammer, Matthias; Krupp, Alexander T.; Brenninger, Thomas; Venkateshvaran, Deepak; Opel, Matthias; Gross, Rudolf; Goennenwein, Sebastian T.B. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Dreher, Lukas [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany); Schoch, Wladimir; Limmer, Wolfgang [Abteilung Halbleiterphysik, Universitaet Ulm, Ulm (Germany)

2011-07-01

In analogy to anisotropic magnetoresistance (AMR), the thermopower of ferromagnetic materials also characteristically depends on the orientation of the magnetization vector. This anisotropic magneto-thermopower - or anisotropic magneto-Seebeck effect (AMS) - has only scarcely been studied to date. Taking the ferromagnetic semiconductor (Ga,Mn)As with its large magneto-resistive effects as a prototype example, we have measured the evolution of both the AMR and the AMS effects at liquid He temperatures as a function of the orientation of a magnetic field applied in the (Ga,Mn)As film plane, for different, fixed magnetic field magnitudes. Our data show that the AMS effect can be adequately modeled only if the symmetry of the (Ga,Mn)As crystal is explicitly taken into account. We quantitatively compare our AMR and AMS measurements with corresponding model calculations, and address the validity of the Mott relations linking the magneto-resistance and the magneto-Seebeck coefficients.

Preparation of n-type Bi{sub 2}Te{sub 3} thermoelectric materials by non-contact dispenser printing combined with selective laser melting

Energy Technology Data Exchange (ETDEWEB)

Wu, Keping; Yan, Yonggao; Zhang, Jian; Mao, Yu; Xie, Hongyao; Zhang, Qingjie; Tang, Xinfeng [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei (China); Yang, Jihui [Department of Materials Science and Engineering, University of Washington, Seattle, WA (United States); Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI (United States)

2017-06-15

The manufacturing cost has been a bottle neck for broader applications of thermoelectric (TE) modules. We have developed a rapid, facile, and low cost method that combines non-contact dispenser printing with selective laser melting (SLM) and we demonstrate it on n-type Bi{sub 2}Te{sub 3}-based materials. Using this approach, single phase n-type Bi{sub 2}Te{sub 2.7}Se{sub 0.3} thin layers with the Seebeck coefficient of -152 μV K{sup -1} at 300 K have been prepared. Assembling such thin layers on top of each other, the performance of thus prepared bulk sample is comparable to Bi{sub 2}Te{sub 3}-based materials fabricated by the conventional techniques. Dispenser printing combined with SLM is a promising manufacturing process for TE materials. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Thermoelectric properties of Al doped Mg{sub 2}Si material

Energy Technology Data Exchange (ETDEWEB)

Kaur, Kulwinder, E-mail: kulwindercmp@gmail.com; Kumar, Ranjan [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Rani, Anita [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India)

2015-08-28

In the present paper we have calculated thermoelectric properties of Al doped Mg{sub 2}Si material (Mg{sub 2−x}Al{sub x}Si, x=0.06) using Pseudo potential plane wave method based on DFT and Semi classical Boltzmann theory. The calculations showed n-type conduction, indicating that the electrical conduction are due to electron. The electrical conductivity increasing with increasing temperature and the negative value of Seebeck Coefficient also show that the conduction is due to electron. The thermal conductivity was increased slightly by Al doping with increasing temperature due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity.

Measurement of the high-temperature Seebeck coefficient of thin films by means of an epitaxially regrown thermometric reference material.

Science.gov (United States)

Ramu, Ashok T; Mages, Phillip; Zhang, Chong; Imamura, Jeffrey T; Bowers, John E

2012-09-01

The Seebeck coefficient of a typical thermoelectric material, silicon-doped InGaAs lattice-matched to InP, is measured over a temperature range from 300 K to 550 K. By depositing and patterning a thermometric reference bar of silicon-doped InP adjacent to a bar of the material under test, temperature differences are measured directly. This is in contrast to conventional two-thermocouple techniques that subtract two large temperatures to yield a small temperature difference, a procedure prone to errors. The proposed technique retains the simple instrumentation of two-thermocouple techniques while eliminating the critical dependence of the latter on good thermal contact. The repeatability of the proposed technique is demonstrated to be ±2.6% over three temperature sweeps, while the repeatability of two-thermocouple measurements is about ±5%. The improved repeatability is significant for reliable reporting of the ZT figure of merit, which is proportional to the square of the Seebeck coefficient. The accuracy of the proposed technique depends on the accuracy with which the high-temperature Seebeck coefficient of the reference material may be computed or measured. In this work, the Seebeck coefficient of the reference material, n+ InP, is computed by rigorous solution of the Boltzmann transport equation. The accuracy and repeatability of the proposed technique can be systematically improved by scaling, and the method is easily extensible to other material systems currently being investigated for high thermoelectric energy conversion efficiency.

The germanides Er{sub 5}Pd{sub 4}Ge{sub 8} and Tm{sub 5}Pd{sub 4}Ge{sub 8}. 3D [Pd{sub 4}Ge{sub 8}] polyanions with Ge{sub 2} dumb-bells and Ge{sub 4} chains in cis-conformation

Energy Technology Data Exchange (ETDEWEB)

Heying, Birgit; Rodewald, Ute C.; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2017-07-01

Tm{sub 5}Pd{sub 4}Ge{sub 8} was synthesized by melting of the elements in an arc-melting furnace. The new germanide was characterized by powder and single-crystal X-ray diffraction: own structure type, P2{sub 1}/m, a=574.3(1), b=1380.4(3), c=836.4(1) pm, β=107.57(2) , V=0.6321 nm{sup 3}, wR2=0.0578, 2533 F{sup 2} values, 86 variables. The palladium and germanium atoms built up a three-dimensional [Pd{sub 4}Ge{sub 8}]{sup 15-} polyanionic network which contains a unique germanium substructure composed of the Zintl anions Ge{sub 2}{sup 6-} dumb-bells and Ge{sub 4}{sup 10-} chains in cis-conformation. The palladium atoms within the network have distorted square pyramidal germanium coordination. The three crystallographically independent thulium atoms have coordination numbers 15, 16 and 17 with partial motifs of the Frank-Kasper type polyhedra. The isotypic germanide Er{sub 5}Pd{sub 4}Ge{sub 8} forms only after annealing the arc-melted sample at 1070 K for 1 week: a=575.14(9), b=1386.3(3), c=838.4(1) pm, β=107.51(2) , V=0.6375 nm{sup 3}.

Numerical Investigation of the Effect of C/O Mole Ratio on the Performance of Rotary Hearth Furnace Using a Combined Model

Science.gov (United States)

Liu, Ying; Wen, Zhi; Lou, Guofeng; Li, Zhi; Yong, Haiquan; Feng, Xiaohong

2014-12-01

In a rotary hearth furnace (RHF) the direct reduction of composite pellets and processes of heat and mass transfer as well as combustion in the chamber of RHF influence each other. These mutual interactions should be considered when an accurate model of RHF is established. This paper provides a combined model that incorporates two sub-models to investigate the effects of C/O mole ratio in the feed pellets on the reduction kinetics and heat and mass transfer as well as combustion processes in the chamber of a pilot-scale RHF. One of the sub-models is established to describe the direct reduction process of composite pellets on the hearth of RHF. Heat and mass transfer within the pellet, chemical reactions, and radiative heat transfer from furnace walls and combustion gas to the surface of the pellet are considered in the model. The other sub-model is used to simulate gas flow and combustion process in the chamber of RHF by using commercial CFD software, FLUENT. The two sub-models were linked through boundary conditions and heat, mass sources. Cases for pellets with different C/O mole ratio were calculated by the combined model. The calculation results showed that the degree of metallization, the total amounts of carbon monoxide escaping from the pellet, and heat absorbed by chemical reactions within the pellet as well as CO and CO2 concentrations in the furnace increase with the increase of C/O mole ratio ranging from 0.6 to 1.0, when calculation conditions are the same except for C/O molar ratio. Carbon content in the pellet has little influence on temperature distribution in the furnace under the same calculation conditions except for C/O mole ratio in the feed pellets.

Preparation and oxidation resistance of single crystalline β-Zn{sub 4}Sb{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu, Hong-xia; Deng, Shu-ping [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China); Li, De-cong [Photoelectric Engineering College, Yunnan Open University, Kunming 650500 (China); Shen, Lan-xian; Cheng, Feng; Wang, Jin-song [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China); Deng, Shu-kang, E-mail: skdeng@126.com [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China)

2016-11-01

This study prepared a Zn-rich single crystal β-Zn{sub 4}Sb{sub 3} using a Sn flux method based on the stoichiometric ratios of Zn{sub 4.4}Sb{sub 3}Sn{sub 3}. The oxidation resistance of the sample was determined by exploring the effects of heat treatment in air on electrical transport properties and thermal stability, which is of practical importance in the application of the material at high temperatures. Results showed that the prepared sample possessed high electrical transport properties, with a high power factor of 1.67×10{sup −3} W m{sup −1} K{sup −2} at 563 K. The heat treatment in air weakened the electrical conductivity of the single crystalline β-Zn{sub 4}Sb{sub 3}, whereas the Seebeck coefficients were rarely independent of the annealing condition. Eventually, the power factor obtained after the first heating at 523 K for 4 h became comparable to that of the as-prepared sample, although it decreased after the second heating at 573 K for 5 h. Nevertheless, the single crystalline β-Zn{sub 4}Sb{sub 3} still possessed a good thermal stability after the heat treatment process.

Influence of Al{sub 2}O{sub 3} addition on microstructure and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Abden, Md. Jaynul [International Islamic Univ., Chittagong (Bangladesh). Dept. of Electrical and Electronic Engineering; Afroze, Jannatul Dil [Noakhali Science and Technology Univ. (Bangladesh). Faculty of Science and Engineering; Gafur, Md. Abdul [Bangladesh Council of Scientific and Industrial Research, Dhaka (Bangladesh). Pilot Plant and Process Development Centre; Chowdhury, Faruque-Uz-Zaman [Chittagong University of Engineering and Technology (Bangladesh). Dept. of Physics

2015-07-01

The effect of the amount of Al{sub 2}O{sub 3} content on microstructure, tetragonal phase stability and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites are investigated in this study. The ceramic composites are obtained by means of uniaxial compacting at 210 MPa and green compacts are sintered at 1550 C for 3 h in air. The monoclinic zirconia (m-ZrO{sub 2}) phase has completely been transformed into tetragonal zirconia (t-ZrO{sub 2}) phase with corresponding higher Al{sub 2}O{sub 3} content. The t-ZrO{sub 2} grains induce transgranular fracture mode that has contribution in improvement of fracture toughness. The maximum flexural strength of 340 MPa, Vickers hardness value of 14.31 GPa and fracture toughness of 5.1 MPa x m{sup 1/2} in the composition containing 40 wt.-% Al{sub 2}O{sub 3} is attributed to the microstructure with t-ZrO{sub 2} grains as inter- and intragranular particles in the Al{sub 2}O{sub 3} grains, which makes it suitable for dental applications.

Extruded Al-Al{sub 2}O{sub 3} composites formed in situ during consolidation of ultrafine Al powders: Effect of the powder surface area

Energy Technology Data Exchange (ETDEWEB)

Balog, Martin, E-mail: martin.balog@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava (Slovakia); Simancik, Frantisek [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava (Slovakia); Walcher, Martin; Rajner, Walter [NMD - New Materials Development GmbH, St. Pantaleon (Austria); Poletti, Cecilia [Institute of Materials Science and Welding, Graz University of Technology, Kopernikusgasse 24/I, A8010 Graz (Austria)

2011-11-25

Highlights: {yields} 25 gas atomised Al 99.5% powders with particle size <10 {mu}m were hot extruded. {yields} The strength of compacts was closely related to powder surface area. {yields} Grain boundary strengthening was enhanced by the presence of in situ Al{sub 2}O{sub 3} dispersoids. {yields} Compacts showed good thermal stability due to grain pinning of Al{sub 2}O{sub 3} dispersoids. - Abstract: Twenty-five samples of commercially available, gas-atomised Al (99.5%) powders with particle sizes <10 {mu}m were hot extruded into Al-Al{sub 2}O{sub 3} composites formed in situ during extrusion. The effect of particle size, surface area, oxygen content and atomisation atmosphere of the powder on the microstructure and mechanical properties of the extruded compacts were studied by Brunauer, Emmett, Teller (BET) analysis, hot gas extraction, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests. Thermal stability of the compacts and the individual strengthening mechanisms operating in the compacts were discussed. It was found that the properties of the compacts stemmed from the extraordinary grain boundary strengthening effect of the ultrafine-grained compacts due to their microstructures. The efficiency of the grain boundary strengthening was significantly enhanced by the presence of nano-metric Al{sub 2}O{sub 3} dispersoids introduced in situ. The strength of the compacts was closely related to the surface area of the powder particles. In addition, the entrapped gasses and chemically bonded humidity had a negative effect on the mechanical properties of the compacts.

Preparation and soft magnetic properties of spark plasma sintered compacts based on Fe–Si–B glassy powder

Energy Technology Data Exchange (ETDEWEB)

Neamţu, B.V., E-mail: bogdan.neamtu@stm.utcluj.ro [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Marinca, T.F.; Chicinaş, I. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Isnard, O. [Institut Néel, CNRS/University Joseph Fourier, BP 166, 38042 Grenoble Cédex 9 (France); Popa, F. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Păşcuţă, P. [Physics and Chemistry Department Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania)

2014-07-05

Highlights: • Amorphous powder of Fe{sub 75}Si{sub 20}B{sub 5} (at.%) was prepared by wet mechanical alloying. • Spark plasma sintering was used for compaction of amorphous Fe{sub 75}Si{sub 20}B{sub 5} powder. • Increasing SPS time/temperature leads to improvement of AC/DC compacts properties. - Abstract: Amorphous powder of Fe{sub 75}Si{sub 20}B{sub 5} (at.%) was prepared by wet mechanical alloying route using benzene as surfactant. The amorphous phase is obtained after 60 h of milling. Structural, morphological, and thermal characteristics were investigated. The as-milled powder consists in micrometric particles with a mean diameter of 10.4 μm which are formed by the agglomeration of smaller particles. The amorphous powder is thermally stable up to the temperature of 490 °C. Spark plasma sintered compacts were prepared from the amorphous powders at sintering temperatures of 800, 850 and 900 °C. The phases formation and their evolution was investigated by X-ray diffraction technique showing that Fe{sub 3}Si and Fe{sub 2}B are the main phases formed during the spark plasma sintering process. Fe{sub 75}Si{sub 20}B{sub 5} (at.%) samples in the form of a ring were investigated in DC and AC magnetization regime. It was found that the boride phase formation (during sintering) and the low density of the compacts affect the magnetic properties of the compacts. In addition, a superficial contamination of the compacts with carbon (a layer of 2–3 μm) was evidenced, contributing thus to their soft magnetic deterioration. Increasing of the saturation induction, maximum relative permeability and initial relative permeability was observed by increasing both sintering temperature and time. It was generally observed that the compacts with high density have higher total core losses at high frequency.

Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

Science.gov (United States)

Selvamanickam, Venkat; Goyal, Amit; Kroeger, Donald M.

1998-01-01

The present invention relate to textured YBa.sub.2 Cu.sub.3 O.sub.x (Y-123) superconductors and a process of preparing them by directional recrystallization of compacts fabricated from quenched YBCO powders at temperatures about 100.degree. C. below the peritectic temperature to provide a superconductor where more than 75% of the YBa.sub.2 Cu.sub.3 O.sub.x phase is obtained without any Y.sub.2 BaCuO.sub.5 .

Refractory of Furnaces to Reduce Environmental Impact

International Nuclear Information System (INIS)

Hanzawa, Shigeru

2011-01-01

The energy load of furnaces used in the manufacturing process of ceramics is quite large. Most of the environmental impact of ceramics manufacturing is due to the CO 2 produced from this high energy load. To improve this situation, R and D has focused on furnace systems and techniques of control in order to reduce energy load. Since furnaces are comprised of refractory, consideration of their mechanical and thermal characteristics is important. Herein are described several refractory types which were chosen through comparison of the characteristics which contribute to heat capacity reduction, heat insulating reinforcement and high emissivity, thereby improving thermal radiation heat transfer efficiency to the ceramic articles. One selected refractory material which will reduce the environmental impact of a furnace, chosen considering low heat capacity and high emissivity characteristics, is SiC. In this study, thermal radiation heat transfer efficiency improvement and its effect on ceramic articles in the furnace and oxidation behaviour were investigated at 1700K. A high density SiC refractory, built into the furnace at construction, has relatively high oxidation durability and has the ability to reduce environmental impact-CO 2 by 10 percent by decreasing the furnace's energy load. However, new oxidation prevention techniques for SiC will be necessary for long-term use in industrial furnaces, because passive to active oxidation transition behaviour of commercial SiC refractory is coming to close ideal.

Refractory of Furnaces to Reduce Environmental Impact

Science.gov (United States)

Hanzawa, Shigeru

2011-10-01

The energy load of furnaces used in the manufacturing process of ceramics is quite large. Most of the environmental impact of ceramics manufacturing is due to the CO2 produced from this high energy load. To improve this situation, R&D has focused on furnace systems and techniques of control in order to reduce energy load. Since furnaces are comprised of refractory, consideration of their mechanical and thermal characteristics is important. Herein are described several refractory types which were chosen through comparison of the characteristics which contribute to heat capacity reduction, heat insulating reinforcement and high emissivity, thereby improving thermal radiation heat transfer efficiency to the ceramic articles. One selected refractory material which will reduce the environmental impact of a furnace, chosen considering low heat capacity and high emissivity characteristics, is SiC. In this study, thermal radiation heat transfer efficiency improvement and its effect on ceramic articles in the furnace and oxidation behaviour were investigated at 1700K. A high density SiC refractory, built into the furnace at construction, has relatively high oxidation durability and has the ability to reduce environmental impact-CO2 by 10 percent by decreasing the furnace's energy load. However, new oxidation prevention techniques for SiC will be necessary for long-term use in industrial furnaces, because passive to active oxidation transition behaviour of commercial SiC refractory is coming to close ideal.

Model based energy benchmarking for glass furnace

International Nuclear Information System (INIS)

Sardeshpande, Vishal; Gaitonde, U.N.; Banerjee, Rangan

2007-01-01

Energy benchmarking of processes is important for setting energy efficiency targets and planning energy management strategies. Most approaches used for energy benchmarking are based on statistical methods by comparing with a sample of existing plants. This paper presents a model based approach for benchmarking of energy intensive industrial processes and illustrates this approach for industrial glass furnaces. A simulation model for a glass furnace is developed using mass and energy balances, and heat loss equations for the different zones and empirical equations based on operating practices. The model is checked with field data from end fired industrial glass furnaces in India. The simulation model enables calculation of the energy performance of a given furnace design. The model results show the potential for improvement and the impact of different operating and design preferences on specific energy consumption. A case study for a 100 TPD end fired furnace is presented. An achievable minimum energy consumption of about 3830 kJ/kg is estimated for this furnace. The useful heat carried by glass is about 53% of the heat supplied by the fuel. Actual furnaces operating at these production scales have a potential for reduction in energy consumption of about 20-25%

The relationship between the particle properties, mechanical behavior, and surface roughness of some pharmaceutical excipient compacts

Energy Technology Data Exchange (ETDEWEB)

Narayan, Padma; Hancock, Bruno C

2003-08-25

Several common pharmaceutical excipient powders were compacted at a constant solid fraction (SF) in order to study the relationship between powder properties, compact surface roughness, and compact mechanical properties such as hardness, elasticity, and brittleness. The materials used in this study included microcrystalline cellulose (MCC), fumaric acid, mannitol, lactose monohydrate, spray dried lactose, sucrose, and dibasic calcium phosphate dihydrate. A slow consolidation process was used to make compacts at a SF of 0.85 (typical for most pharmaceutical tablets) from single excipient components. A model was proposed to describe the surface roughness of compacts based on the brittle or ductile deformation tendencies of the powder materials. The roughness profile would also be dependent upon the magnitude of the compression stress in relation to the yield stress (onset of irreversible deformation) values of the excipients. It was hypothesized that brittle materials would produce smooth compacts with high surface variability due to particle fracture, and the converse would apply for ductile materials. Compact surfaces should be smoother if the materials were compressed above their yield pressure values. Non-contact optical profilometry was used along with scanning electron microscopy to quantify and characterize the surface morphology of the excipient compacts. The roughness parameters R{sub a} (average roughness), R{sub q} (RMS roughness), R{sub q}/R{sub a} (ratio describing surface variability), and R{sub sk} (skewness) were found to correlate with the deformation properties of the excipients. Brittle materials such as lactose, sucrose, and calcium phosphate produced compacts with low values of R{sub a} and R{sub q}, high variability, and negative R{sub sk}. The opposite was found with plastic materials such as MCC, mannitol, and fumaric acid. The highly negative skewness values for brittle material compacts may indicate their propensity to be vulnerable to

Nuclear techniques for the inspection of blast furnaces

International Nuclear Information System (INIS)

Schweitzer, J. S.; Lanza, R. C.

1999-01-01

Carbon hearth wall failures in blast furnaces create safety risks and require a large expense to repair. To avoid failures they are replaced early, incurring costs in wasted hearth wall use. Two non-invasive measurements provide realtime analysis of wall integrity. The two major failure modes are erosion of carbon thickness and iron-filled cracks in the bricks. Measurements of backscattered gamma-ray spectra and thermal neutron decay rate can identify both phenomena. Gamma-ray spectra from a compact Linac beam primarily respond to average carbon thickness. Neutron decay time, using a pulsed neutron source, is sensitive to iron in the carbon volume. Each measurement is sensitive to the other failure made, but the combination permits each phenomenon to be resolved. These techniques can detect a high atomic number and thermal neutron absorption cross section material behind one of low atomic number and thermal neutron absorption cross section

Solar Convective Furnace for Metals Processing

Science.gov (United States)

Patidar, Deepesh; Tiwari, Sheetanshu; Sharma, Piyush; Pardeshi, Ravindra; Chandra, Laltu; Shekhar, Rajiv

2015-11-01

Metals processing operations, primarily soaking, heat treatment, and melting of metals are energy-intensive processes using fossil fuels, either directly or indirectly as electricity, to operate furnaces at high temperatures. Use of concentrated solar energy as a source of heat could be a viable "green" option for industrial heat treatment furnaces. This paper introduces the concept of a solar convective furnace which utilizes hot air generated by an open volumetric air receiver (OVAR)-based solar tower technology. The potential for heating air above 1000°C exists. Air temperatures of 700°C have already been achieved in a 1.5-MWe volumetric air receiver demonstration plant. Efforts to retrofit an industrial aluminium soaking furnace for integration with a solar tower system are briefly described. The design and performance of an OVAR has been discussed. A strategy for designing a 1/15th-scale model of an industrial aluminium soaking furnace has been presented. Preliminary flow and thermal simulation results suggest the presence of recirculating flow in existing furnaces that could possibly result in non-uniform heating of the slabs. The multifarious uses of concentrated solar energy, for example in smelting, metals processing, and even fuel production, should enable it to overcome its cost disadvantage with respect to solar photovoltaics.

Energy Saving in Industrial Annealing Furnaces

Directory of Open Access Journals (Sweden)

Fatma ÇANKA KILIÇ

2018-03-01

Full Text Available In this study, an energy efficiency studies have been carried out in a natural gas-fired rolling mill annealing furnace of an industrial establishment. In this context, exhaust gas from the furnace has been examined in terms of waste heat potential. In the examinations that have been made in detail; waste heat potential was found as 3.630,31 kW. Technical and feasibility studies have been carried out to realize electricity production through an Organic Rankine Cycle (ORC system for evaluating the waste heat potential of the annealing furnace. It has been calculated that 1.626.378,88 kWh/year of electricity can be generated by using the exhaust gas waste heat of the annealing furnace through an ORC system to produce electric energy with a net efficiency of 16%. The financial value of this energy was determined as 436.032,18 TL/year and the simple repayment period of the investment was 8,12 years. Since the annealing period of the annealing furnace is 2800 hours/year, the investment has not been found to be feasible in terms of the feasibility studies. However, the investment suitability can be assured when the annealing furnace is operating at full capacity for 8,000 hours or more annually.

The Seebeck coefficient of monocrystalline α-SiC and polycrystalline β-SiC measured at 300-533 K

Science.gov (United States)

Abu-Ageel, N.; Aslam, M.; Ager, R.; Rimai, L.

2000-01-01

The temperature dependence of the Seebeck coefficient of polycrystalline icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> -SiC films deposited on quartz substrates by laser ablation and of commercially available icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> -SiC wafers is reported in a temperature range of 300-533 K for the first time. The Seebeck emf of icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> -SiC substrates and icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> -SiC samples ranges between -9 µV °C-1 and -108 µV °C-1 which is higher than that of commercial Pt thermocouples.

Design and Development of Tilting Rotary Furnace

Science.gov (United States)

Sai Varun, V.; Tejesh, P.; Prashanth, B. N.

2018-02-01

Casting is the best and effective technique used for manufacturing products. The important accessory for casting is furnace. Furnace is used to melt the metal. A perfect furnace is one that reduces the wastage of material, reduces the cost of manufacturing and there by reduces the cost of production. Of all the present day furnaces there may be wastage of material, and the chances of increasing the time of manufacturing as the is continuous need of tilting of the furnace for every mould and then changing the moulds. Considering these aspects, a simple and least expensive tilting rotary furnace is designed and developed. The Tilting and Rotary Furnace consists of mainly melting chamber and the base. The metal enters the melting chamber through the input door that is provided on the top of the melting chamber. Inside the melting chamber there is a graphite furnace. The metal is melted in the graphite crucible. An insulation of ceramic fibre cloth is provided inside the furnace. The metal is melted using Propane gas. The propane gas is easily available and economic. The gas is burned using a pilot burner. The pilot burner is more efficient that other burners. The pilot burner is lit with a push button igniter. The pilot burner is located at the bottom of the combustion chamber. This enables the uniform heating of the metal inside the crucible. The temperature inside the melting chamber is noted using a temperature sensor. The gas input is cut-off if the temperature is exceeding a specific temperature. After the melting of the metal is done the furnace is tilted and after the mould is filled it is rotated. The external gears are used to controlling the tilting. The results of studies carried out for the design & development of low cost, simple furnace that can be mounted anywhere on the shop floor and this can be very much useful for the education purposes and small scale manufacturing. The furnace can be rotated in 360 degrees and can help in reducing the time taken

Measurement setup for the simultaneous determination of diffusivity and Seebeck coefficient in a multi-anvil apparatus.

Science.gov (United States)

Jacobsen, M K; Liu, W; Li, B

2012-09-01

In this paper, a high pressure setup is presented for performing simultaneous measurements of Seebeck coefficient and thermal diffusivity in multianvil apparatus for the purpose of enhancing the study of transport phenomena. Procedures for the derivation of Seebeck coefficient and thermal diffusivity/conductivity, as well as their associated sources of errors, are presented in detail, using results obtained on the filled skutterudite, Ce(0.8)Fe(3)CoSb(12,) up to 12 GPa at ambient temperature. Together with recent resistivity and sound velocity measurements in the same apparatus, these developments not only provide the necessary data for a self-consistent and complete characterization of the figure of merit of thermoelectric materials under pressure, but also serve as an important tool for furthering our knowledge of the dynamics and interplay between these transport phenomena.

Comprehensive Numerical Modeling of the Blast Furnace Ironmaking Process

Science.gov (United States)

Zhou, Chenn; Tang, Guangwu; Wang, Jichao; Fu, Dong; Okosun, Tyamo; Silaen, Armin; Wu, Bin

2016-05-01

Blast furnaces are counter-current chemical reactors, widely utilized in the ironmaking industry. Hot reduction gases injected from lower regions of the furnace ascend, reacting with the descending burden. Through this reaction process, iron ore is reduced into liquid iron that is tapped from the furnace hearth. Due to the extremely harsh environment inside the blast furnace, it is difficult to measure or observe internal phenomena during operation. Through the collaboration between steel companies and the Center for Innovation through Visualization and Simulation, multiple computational fluid dynamics (CFD) models have been developed to simulate the complex multiphase reacting flow in the three regions of the furnace, the shaft, the raceway, and the hearth. The models have been used effectively to troubleshoot and optimize blast furnace operations. In addition, the CFD models have been integrated with virtual reality. An interactive virtual blast furnace has been developed for training purpose. This paper summarizes the developments and applications of blast furnace CFD models and the virtual blast furnace.

Measures on fireside emission reduction during wood combustion in industrial furnaces; Massnahmen zur feuerungsseitigen Emissionsminderung bei der Holzverbrennung in gewerblichen Feuerungsanlagen

Energy Technology Data Exchange (ETDEWEB)

Zuberbuehler, U.

2002-07-01

The combustion of natural wood chips in current automatic firing systems leads to emissions of NO{sub x} < 200 mg/m{sup 3} and Particular Matter (PM)<50 mg/m{sup 3}. During the combustion of chipboard residues NO{sub x} emissions can reach 1000 mg/m{sup 3} and PM 500 mg/m{sup 3}, as they accrue particularly at furniture industry and carpenters. To achieve better particle burnout and lower NO{sub x} concentrations a new firing concept has been developed and tested. State of the art in the area of commercial wood firings was the {lambda}- and temperature controlled underfeed firing. Based on this firing type, a stage combustion was realized by a separation of the furnace in primary and secondary combustion chamber. Within the first step of development the burnout zone was optimised to improve particle burnout with simultaneous particle separation. Secondary air supply was made with a special fan to produce a swirl flow inside the cylindrical combustion chamber. Similar as in a cyclone particles were carried in a reverse flow to the furnace wall where is sufficient time for burnout. The good mixing performance of air and combustion gases is another benefit of the produced swirl flow. The aim of further development was to achieve the necessary conditions for primary NO{sub x} reduction with a new design of the primary zone of the furnace. Therefore hot gas from the end of combustion chamber or exhaust gas was recirculated to reduce the amount of primary air. The new primary zone of the combustion chamber was combined with the well working burnout zone with integrated particle separation. The combustion behaviour of this combined furnace was investigated and optimised on a test stand. During continuous combustion of coated chipboards (fuel N-content 4,3%) NO{sub x} concentrations of 450 mg/m{sup 3} were measured, which correspond to a 40% reduction in comparison with a common underfed firing. CO concentrations of 30 mg/m{sup 3} were on a very low level and particle

Incorporation of cement bypass flue dust in fly ash and blast furnace slag-based geopolymer

Directory of Open Access Journals (Sweden)

Mohamed E. Sultan

2018-06-01

Full Text Available This work utilizes cement kiln dust in fly ash and blast furnace slag-based geopolymer. Geopolymer cement was produced using different compositions of ground, granulated blast furnace slag with fly ash and cement bypass flue dust. Crystalline sodium metasilicate pentahydrate was used as an activator at 10, 15 and 20% (by weight of the geopolymer source materials. The geopolymer is formed in the solid state like ordinary Portland cement. The mechanical and chemical properties of the geopolymeric materials were examined. Measuring of mechanical properties by compressive strength of the hardened geopolymer pastes at different curing ages; microstructure was evaluated by X-ray diffraction (XRD and scanning electron microscope (SEM; thermal properties were estimated by thermogravimetry analysis (TGA and derivative thermogravimetric analysis (DTG. The results indicate that the compressive strength of the geopolymer pastes is increased with higher Na2SiO3.5H2O content. The geopolymeric properties were enhanced by higher pH, which helps in the dissolution of geopolymer source materials during geopolymerization. SEM showed that mixes containing 15 and 20% sodium metasilicate had more compact and dense structures. On the other hand, GGBFS mix (G-20 exhibits more hydration and geopolymeric products during TGA/DTG compared with other mixes which contain FA with/without GGBFS. Keywords: Cement bypass flue dust, Geopolymer, Ground granulated blast furnace, Fly ash

Rheological study of self-compacting mortars based on ternary cements

Directory of Open Access Journals (Sweden)

Elhadja Dada

2018-01-01

Full Text Available Self-compacting concrete (SCC is able to provide the ability to be easily implemented without vibration and to achieve spectacular structures, by its high fluidity and its rheological stability. By against its formulation requires a large volume of cement, which is necessary to allow its flow. The current environmental considerations lead to reduce the production of clinker however, it is essential to use cementitious additions to replace cement, because of their high availability and their moderate price. Furthermore, their use contributes in a simple and economical way to solve the problems related to the environment. The objective of our work is to study the effects of the incorporation of mineral additions such as: blast furnace slag of El-Hadjar (BFS, and marble powder (MP on the rheological parameters of selfcompacting mortars developed in different combinations in ternary system with a substitution rate ranging from 20% to 60%. According to this study, it been found that the substitution of cement by blast furnace slag and marble powder has negatively affected the rheological behavior of the mixtures. In addition, a considerable decrease in the rheological parameters has been achieved with a substitution rate of 20% of slag and 30% of marble powder. As well as an improvement of workability has been proven to self-compacting mortars and this is due to the increase of ternary cement replacement rate by marble powder from 20% to 30%.

Sealed rotary hearth furnace with central bearing support

Science.gov (United States)

Docherty, James P.; Johnson, Beverly E.; Beri, Joseph

1989-01-01

The furnace has a hearth which rotates inside a stationary closed chamber and is supported therein on vertical cylindrical conduit which extends through the furnace floor and is supported by a single center bearing. The charge is deposited through the furnace roof on the rim of the hearth as it rotates and is moved toward the center of the hearth by rabbles. Externally generated hot gases are introduced into the furnace chamber below the hearth and rise through perforations in the hearth and up through the charge. Exhaust gases are withdrawn through the furnace roof. Treated charge drops from a center outlet on the hearth into the vertical cylindrical conduit which extends downwardly through the furnace floor to which it is also sealed.

Thermoelectric characterization of Sb{sub 2}Te{sub 3} thin films deposited by ALD

Energy Technology Data Exchange (ETDEWEB)

Zastrow, Sebastian; Schumacher, Christian; Nielsch, Kornelius [University of Hamburg (Germany); Regus, Matthias [University of Kiel (Germany); Schulz, Stephan [University of Duisburg-Essen (Germany)

2012-07-01

Thermoelectric materials can be used as temperature sensors or peltier cooling devices as well as to recover a part of the massive losses of energy due to the waste heat generated in fossil-fuel driven power plants and vehicles. Antimony Telluride (Sb{sub 2}Te{sub 3}) is a p-doped semiconductor and in the focus of interest for room temperature applications because of its thermoelectric peak performance at around 350 K. However, thermoelectric properties of Sb{sub 2}Te{sub 3} ALD thin films have not been reported yet. Based on the work of Pore et al., Sb{sub 2}Te{sub 3} is deposited with a home-made reactor on SiO{sub 2} by using (Et{sub 3}Si){sub 2}Te and SbCl{sub 3}. The surface roughness as well as the growth rate depend strongly on the deposition temperature as reported by Cu et al. To check the preferential growth directions and the composition, XRD and EDX measurements are carried out. The thermoelectric properties are influenced by the deposition parameters. Therefore, spatial scans of the Seebeck coefficient are performed and the electrical resistivity is measured. In order to enhance the thermoelectric performance, a first optimization by short annealing processes is done under helium atmosphere up to 570 K. The authors would like to thank the ''Karl-Vossloh-Stiftung''.

Emission spectroscopy for coal-fired cyclone furnace diagnostics

Energy Technology Data Exchange (ETDEWEB)

Wehrmeyer, J.A.; Boll, D.E.; Smith, R. [Vanderbilt University, Nashville, TN (United States). Dept. of Mechanical Engineering

2003-08-01

Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained. Spectra from all cyclone burners show emission lines for the trace elements Li, Na, K, and Rb, as well as the molecular species OH and CaOH. The Ca emission line is detected at the burner end of both the fuel-rich and fuellean cyclone furnaces but is not detected at the outlet ends of either furnace type. Along with the disappearance of Ca is a concomitant increase in the CaOH signal at the outlet end of both types of furnaces. The OH signal strength is in general stronger when viewing at the burner end rather than the exhaust end of both the fuel-rich and fuel-lean cyclone furnaces, probably due to high, non-equilibrium amounts of OH present inside the furnace. Only one molecular species was detected that could be used as a measure of air/fuel ratio: MgOH. It was detected at the burner end of fuel-rich cyclone furnaces but not detected in fuel-lean cyclone furnaces. More direct markers of air/fuel ratio, such as CO and 02 emission, were not detected, probably due to the generally weak nature of molecular emission relative to ambient blackbody emission present in the cyclone furnaces, even at ultraviolet wavelengths.

AUTOMATION OF GLASS TEMPERING FURNACE BY USING PLC

Directory of Open Access Journals (Sweden)

Abdullah BÜYÜKYILDIZ

2007-02-01

Full Text Available In this study, a furnace which is used for observation of environments under high temperature, and also used for manufacturing of glasses which are resisted to high temperature has been designed and implemented. Automation of this system has been done by using PLC. Operating parameters of furnace such as materials entering, the furnace, the local temperature control of furnace, cooling control and materials outing have been sensed with Hall Effect Sensor. Furthermore, the observation of parameters of furnace on screen has been provided with SCADA software. Obtained products have been shown the system works successfully.

Spin-dependent Seebeck coefficients of Ni80Fe20 and Co in nanopillar spin valves

NARCIS (Netherlands)

Dejene, F. K.; Flipse, J.; van Wees, B. J.

2012-01-01

We have experimentally determined the spin-dependent Seebeck coefficient of permalloy (Ni80Fe20) and cobalt (Co) using nanopillar spin valve devices, a stack of two ferromagnetic layers separated by a nonmagnetic layer. The devices were specifically designed to separate heat-related effects from

A cylindrical furnace for absorption spectral studies

Indian Academy of Sciences (India)

A cylindrical furnace with three heating zones, capable of providing a temperature of 1100°C, has been fabricated to enable recording of absorption spectra of high temperature species. The temperature of the furnace can be controlled to ± 1°C of the set temperature. The salient feature of this furnace is that the material ...

Ternary indides Eu{sub 2}Pd{sub 2}In and Eu{sub 2}Pt{sub 2}In

Energy Technology Data Exchange (ETDEWEB)

Muts, Ihor [Inorganic Chemistry Department, Ivan Franko National University of Lviv (Ukraine); Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Zaremba, Vasyl I. [Inorganic Chemistry Department, Ivan Franko National University of Lviv (Ukraine); Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany)

2012-01-15

The indides Eu{sub 2}Pd{sub 2}In and Eu{sub 2}Pt{sub 2}In were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were characterized by powder X-ray diffraction. The structures were refined on the basis of single-crystal X-ray diffractometer data: HT-Pr{sub 2}Co{sub 2}Al type, C2/c, a = 1035.7(2), b = 592.9(1), c = 823.6(2) pm, β = 104.26(1) , wR2 = 0.026, 1075 F{sup 2} values, 25 variables for Eu{sub 2}Pd{sub 2}In and a = 1017.2(2), b = 588.7(1), c = 826.5(1) pm, β = 103.76(1) , wR2 = 0.062, 706 F{sup 2} values, 25 variables for Eu{sub 2}Pt{sub 2}In. The indium atoms have four platinum (palladium) neighbors in strongly distorted tetrahedral coordination at Pt-In and Pd-In distances ranging from 273 to 275 pm. These InPd{sub 4/2} and InPt{sub 4/2} units are condensed via common edges to infinite InPd{sub 2} and InPt{sub 2} chains, which are surrounded by the europium atoms. The chains form the motif of hexagonal rod packing. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Crystal structure and transport properties of gamma-Na sub x CoO sub 2 (x=0.67 approx 0.75)

CERN Document Server

Ono, Y; Miyazaki, Y; Kajitani, T; Ishii, Y

2003-01-01

Crystal structure and transport properties of gamma-Na sub x CoO sub 2 have been studied in the range of x=0.67-0.75. Single-phase samples were prepared by sintering mixture of raw materials, Na sub 2 CO sub 3 (99.5%) and Co sub 3 O sub 4 (99.9%). Na/Co composition ratio (x) was determined by inductively coupled plasma (ICP) analysis. The crystal structure parameters were refined by Rietveld analysis of powder neutron diffraction intensities, assuming P6 sub 3 /mmc type space symmetry. Little changes in the crystal structure are noticed, except for Na contents. Electric resistivity rho and Seebeck coefficient S were measured at temperatures between 380 K and 1000 K by the standard four-probe method and temperature gradient method, respectively. The rho-T curves exhibit the thermal hysteresis in the initial measurement. But, in the following measurement, the thermal hysteresis is significantly suppressed. The S was slightly higher in the sample with x = 0.75 than in the others at any temperatures. Power factor...

Remote sensing of stratospheric O{sub 3} and NO{sub 2} using a portable and compact DOAS spectrometer

Energy Technology Data Exchange (ETDEWEB)

Raponi, M M; Wolfram, E; Quel, E J [Division LIDAR, Centro de Investigaciones en Laseres y Aplicaciones, CEILAP (CITEFA-CONICET), Juan B. de La Salle 4397 (B1603ALO), Villa Martelli, Buenos Aires (Argentina); Jimenez, R [Department of Chemical and Environmental Engineering, Universidad Nacional de Colombia, Bogota (Colombia); Tocho, J O, E-mail: mraponi@citefa.gov.ar [Centro de Investigaciones Opticas, CIOp (CONICET La Plata-CIC), Buenos Aires (Argentina)

2011-01-01

The use of passive and active remote sensing systems has largely contributed to advance our understanding of important atmospheric phenomena. Here we present a compact and portable passive DOAS (Differential Optical Absorption Spectroscopy) system, developed for measuring the vertical column density (VCD) of multiple atmospheric trace gases. We highlight the main characteristics of the system components: a mini-spectrometer (HR4000, Ocean Optics), two optical fibers (400 {mu}m of core, 6 m and 25 cm of longitude), an external shutter and the control/data processing software. Nitrogen dioxide (NO{sub 2}) and ozone (O{sub 3}) VCDs are derived from solar spectra acquired during twilights (87{sup 0} - 91{sup 0} zenithal angles) using the DOAS technique. The analysis is carried out by solving the Beer-Lambert-Bouger (BLB) law for the main atmospheric absorbers at selected wavelength ranges. The algorithm minimizes the fitting residuals to the BLB law, having as unknown the slant column density (SCD) of the species to determine. We present measurements carried out at the Marambio Antarctic Base (64{sup 0} 14' 25'' S; 56{sup 0} 37' 21'' W, 197 m asl) during January - February 2008. In addition, we compare our results with co-located measurements performed with EVA, a visible absorption spectrometer of Instituto Nacional de Tecnica Aeroespacial (INTA, Spain), a Dobson spectrophotometer of Servicio Meteorologico Nacional (SMN, Argentine) and the Ozone Monitoring Instrument (OMI), on board AURA satellite.

Modeling and Simulation of Claus Unit Reaction Furnace

Directory of Open Access Journals (Sweden)

Maryam Pahlavan

2016-01-01

Full Text Available Reaction furnace is the most important part of the Claus sulfur recovery unit and its performance has a significant impact on the process efficiency. Too many reactions happen in the furnace and their kinetics and mechanisms are not completely understood; therefore, modeling reaction furnace is difficult and several works have been carried out on in this regard so far. Equilibrium models are commonly used to simulate the furnace, but the related literature states that the outlet of furnace is not in equilibrium and the furnace reactions are controlled by kinetic laws; therefore, in this study, the reaction furnace is simulated by a kinetic model. The predicted outlet temperature and concentrations by this model are compared with experimental data published in the literature and the data obtained by PROMAX V2.0 simulator. The results show that the accuracy of the proposed kinetic model and PROMAX simulator is almost similar, but the kinetic model used in this paper has two importance abilities. Firstly, it is a distributed model and can be used to obtain the temperature and concentration profiles along the furnace. Secondly, it is a dynamic model and can be used for analyzing the transient behavior and designing the control system.

Feasibility of high-resolution continuum source molecular absorption spectrometry in flame and furnace for sulphur determination in petroleum products

Energy Technology Data Exchange (ETDEWEB)

Kowalewska, Zofia, E-mail: zofia.kowalewska@obr.pl

2011-07-15

For the first time, high-resolution molecular absorption spectrometry with a high-intensity xenon lamp as radiation source has been applied for the determination of sulphur in crude oil and petroleum products. The samples were analysed as xylene solutions using vaporisation in acetylene-air flame or in an electrothermally heated graphite furnace. The sensitive rotational lines of the CS molecule, belonging to the {Delta}{nu} = 0 vibrational sequence within the electronic transition X{sup 1}{Sigma}{sup +} {yields} A{sup 1}{Pi}, were applied. For graphite furnace molecular absorption spectrometry, the Pd + Mg organic modifier was selected. Strong interactions with Pd atoms enable easier decomposition of sulphur-containing compounds, likely through the temporal formation of Pd{sub x}S{sub y} molecules. At the 258.056 nm line, with the wavelength range covering central pixel {+-} 5 pixels and with application of interactive background correction, the detection limit was 14 ng in graphite furnace molecular absorption spectrometry and 18 mg kg{sup -1} in flame molecular absorption spectrometry. Meanwhile, application of 2-points background correction found a characteristic mass of 12 ng in graphite furnace molecular absorption spectrometry and a characteristic concentration of 104 mg kg{sup -1} in flame molecular absorption spectrometry. The range of application of the proposed methods turned out to be significantly limited by the properties of the sulphur compounds of interest. In the case of volatile sulphur compounds, which can be present in light petroleum products, severe difficulties were encountered. On the contrary, heavy oils and residues from distillation as well as crude oil could be analysed using both flame and graphite furnace vaporisation. The good accuracy of the proposed methods for these samples was confirmed by their mutual consistency and the results from analysis of reference samples (certified reference materials and home reference materials with

Colligative thermoelectric transport properties in n-type filled CoSb{sub 3} determined by guest electrons in a host lattice

Energy Technology Data Exchange (ETDEWEB)

Lim, Young Soo, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com [Department of Materials System Engineering, Pukyong National University, Busan 48547 (Korea, Republic of); Park, Kwan-Ho; Tak, Jang Yeul; Lee, Soonil; Seo, Won-Seon, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com [Energy and Environmental Division, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851 (Korea, Republic of); Park, Cheol-Hee, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com; Kim, Tae Hoon; Park, PumSuk [LG Chem/Research Park, Daejeon 34122 (Korea, Republic of); Kim, Il-Ho [Department of Materials Science and Engineering, Korea National University of Transportation, Chungju 27909 (Korea, Republic of); Yang, Jihui [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States)

2016-03-21

Among many kinds of thermoelectric materials, CoSb{sub 3} has received exceptional attention for automotive waste heat recovery. Its cage structure provides an ideal framework for the realization of phonon-glass electron-crystal strategy, and there have been numerous reports on the enhanced thermoelectric performance through the independent control of the thermal and electrical conductivity by introducing fillers into its cage sites. Herein, we report colligative thermoelectric transport properties in n-type CoSb{sub 3} from the viewpoint of “guest electrons in a host lattice.” Both the Seebeck coefficient and the charge transport properties are fundamentally determined by the concentration of the guest electrons, which are mostly donated by the fillers, in the conduction band of the host CoSb{sub 3}. Comparing this observation to our previous results, colligative relations for both the Seebeck coefficient and the mobility were deduced as functions of the carrier concentration, and thermoelectric transport constants were defined to predict the power factor in filled CoSb{sub 3}. This discovery not only increases the degree of freedom for choosing a filler but also provides the predictability of power factor in designing and engineering the n-type filled CoSb{sub 3} materials.

Thickness oscillations of the transport properties in n-type Bi{sub 2}Te{sub 3} topological insulator thin films

Energy Technology Data Exchange (ETDEWEB)

Rogacheva, E.I., E-mail: rogacheva@kpi.kharkov.ua [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze Street, Kharkov 61002 (Ukraine); Budnik, A.V.; Sipatov, A.Yu.; Nashchekina, O.N. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze Street, Kharkov 61002 (Ukraine); Fedorov, A.G. [Institute for Single Crystals of NAS of Ukraine, 60 Lenin Prospect, Kharkov 61001 (Ukraine); Dresselhaus, M.S.; Tang, S. [Department of Electrical Engineering and Computer Science and Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

2015-11-02

The dependences of the electrical conductivity, Seebeck coefficient and Hall coefficient on the thickness (d = 20–155 nm) of the n-type thin films grown on the glass substrates by the thermal evaporation in vacuum of the n-type Bi{sub 2}Te{sub 3} topological insulator crystals have been measured. It has been established that these dependences have an oscillatory character with a substantial amplitude. The obtained results are interpreted in terms of quantum size effects, taking into account the peculiar properties of the surface layers of the Bi{sub 2}Te{sub 3} films connected with the topological insulator nature of the bismuth telluride. - Highlights: • The thickness dependences of Bi{sub 2}Te{sub 3} thin films kinetic coefficients were obtained. • The dependences have oscillatory character with a substantial undamped amplitude. • The oscillation period increases with decreasing film thickness. • The oscillations are attributed to electron confinement in the film growth direction. • It is suggested that topological surface layer affects quantum processes in films.

Magnetic orientation of paraffin in a magnetic levitation furnace

Energy Technology Data Exchange (ETDEWEB)

Takahashi, K.; Umeki, C.; Mogi, I.; Koyama, K.; Awaji, S.; Motokawa, M.; Watanabe, K

2004-04-30

Containerless melting of paraffin under a magnetic levitation condition has been performed by using a cryogen-free hybrid magnet and two kinds of laser furnaces. One is local irradiation of CO{sub 2} laser light at the top of the sample. The other is homogeneous irradiation of YAG laser light with a concave ring mirror. In the latter case, reduction of the Marangoni convection on the surface of the sample and the magnetic orientation of paraffin molecules were observed. The magnetic anisotropy of the spherical sample was confirmed by the measurement of magnetization and X-ray diffraction.

Design of a rotating-hearth furnace

Energy Technology Data Exchange (ETDEWEB)

Behrens, H A [Verein Deutscher Eisenhuettenleute (VDEh), Duesseldorf (Germany, F.R.)

1979-10-01

Presented in two parts, this paper is intended to provide an outline of the theoretical fundamentals for the design of rotating-hearth furnaces for heating round stock and deals with the characteristic design features of such furnaces.

Ba{sub 4}In{sub 8}Sb{sub 16}: Thermoelectric properties of a new layered Zintl phase with infinite zigzag Sb chains and pentagonal tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, S J; Hu, S; Uher, C; Kanatzidis, M G

1999-11-01

A new Zintl phase Ba{sub 4}In{sub 8}Sb{sub 16} was obtained from a direct element combination reaction of the elements in a sealed graphite tube at 700 C, and its structure was determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group Pnma (No. 62) with a = 10.166(3) {angstrom}, b = 4.5239(14) {angstrom}, c = 19.495(6) {angstrom}, and Z = 1. Ba{sub 4}In{sub 8}Sb{sub 16} has a two-dimensional structure with thick corrugated (In{sub 8}Sb{sub 16}){sup 8{minus}} layers separated by Ba{sup 2+} ions. In the layer, InSb{sub 4} tetrahedra are connected by sharing three corners and by bridging the fourth corner in such a manner that infinite pentagonal tubes are formed. The compound is a narrow band gap ({approximately} 0.10 eV) semiconductor and satisfies the classical Zintl rule. Band structure calculations confirm that the material is a semiconductor and indicate that it has optimized In-Sb bonding interactions. Polycrystalline ingots of Ba{sub 4}In{sub 8}Sb{sub 16} show room-temperature electrical conductivity of 135 S/cm and a Seebeck coefficient of 70 {micro}V/K. The thermal conductivity of Ba{sub 4}In{sub 8}Sb{sub 16} is about 1.7 W/m{sm{underscore}bullet}K in the temperature range 150--300 K.

Glass: Rotary Electric Glass Furnace

Energy Technology Data Exchange (ETDEWEB)

Recca, L.

1999-01-29

Compared to conventional gas-fired furnaces, the new rotary electric furnace will increase energy efficiency while significantly reducing air emissions, product turnaround time, and labor costs. As this informative new fact sheet explains, the thousand different types of glass optical blanks produced for the photonics industry are used for lasers, telescopes, cameras, lights, and many other products.

Paired Straight Hearth Furnace - Transformational Ironmaking Process

Energy Technology Data Exchange (ETDEWEB)

Lu, Wei-Kao [McMaster Univ., Hamilton, ON (Canada); Debski, Paul [Andritz Metals Inc.,Canonsburg, PA (United States)

2014-11-19

The U. S. steel industry has reduced its energy intensity per ton of steel shipped by 33% since 1990. However, further significant gains in energy efficiency will require the development of new, transformational iron and steelmaking processes. The Paired Straight Hearth Furnace (PSH) process is an emerging alternative high productivity, direct reduced iron (DRI) technology that may achieve very low fuel rates and has the potential to replace blast furnace ironmaking. The PSH furnace can operate independently or may be coupled with other melting technologies to produce liquid hot metal that is both similar to blast furnace iron and suitable as a feedstock for basic oxygen steelmaking furnaces. The PSH process uses non-metallurgical coal as a reductant to convert iron oxides such as iron ore and steelmaking by-product oxides to DRI pellets. In this process, a multi-layer, nominally 120mm tall bed of composite “green balls” made from oxide, coal and binder is built up and contained within a moving refractory hearth. The pellet bed absorbs radiant heat energy during exposure to the high temperature interior refractory surfaces of the PSH while generating a strongly reducing gas atmosphere in the bed that yields a highly metalized DRI product. The PSH concept has been well tested in static hearth experiments. A moving bed design is being developed. The process developers believe that if successful, the PSH process has the potential to replace blast furnaces and coke ovens at a fraction of the operating and capital cost while using about 30% less energy relative to current blast furnace technology. DRI output could also feed electric arc furnaces (EAFs) by displacing a portion of the scrap charge.

Industrial furnace with improved heat transfer

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1993-07-20

A method is described for effecting improved heat transfer with in an industrial furnace having a cylindrical furnace section, a door at one end of the furnace section, an end plate at the opposite end of the section a circular fan plate concentrically positioned within the furnace section to define a cylindrical fan chamber between the plate and the end section with a fan there between and a heat treat chamber between the plate and the door, the fan plate defining a non-orificing annular space extending between the interior of the cylindrical furnace section and the outer edge of the plate, the plate having a centrally located under-pressure opening extending there through and a plurality of circumferentially spaced tubular heating elements extending through the annular space into the heat treating chamber, the method comprising the steps of: (a) heating the heating elements to a temperature which is hotter that the temperature of the work within the heat treating chamber; (b) rotating the fan at a speed sufficient to form a portion of the furnace atmosphere as a wind mass swirling about the fan chamber; (c) propagating the wind mass through the annular space into the heat treating chamber as a swirling wind mass in the form of an annulus, the wind mass impinging the heating elements to establish heat transfer contact therewith while the mass retains its annulus shape until contacting the door and without any significant movement of the wind mass into the center of the heat treating chamber; (d) drawing the wind mass through the under-pressure zone after the wind mass comes into heat transfer contact with the work in the heat treating chamber; and (e) thereafter heating the work by radiation from the beating elements at high furnace temperatures in excess of about 1,600 F.

Optical cavity furnace for semiconductor wafer processing

Science.gov (United States)

Sopori, Bhushan L.

2014-08-05

An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

Thermal cycling behavior of La{sub 2}Zr{sub 2}O{sub 7} coating with the addition of Y{sub 2}O{sub 3} by EB-PVD

Energy Technology Data Exchange (ETDEWEB)

Xu Zhenhua [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He Limin, E-mail: he_limin@yahoo.co [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Chen Xiaolong; Zhao Yu [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Mu Rende; He Shimei [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao Xueqiang, E-mail: xcao@ciac.jl.c [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2010-10-15

Thermal barrier coatings (TBCs) of La{sub 2}Zr{sub 2}O{sub 7} (LZ) with the addition of 3 wt.% Y{sub 2}O{sub 3} (LZ3Y) were deposited by electron beam-physical vapor deposition (EB-PVD). The phase structures, surface and cross-sectional morphologies, cyclic oxidation behaviors of these coatings were studied in detail. The thermal cycling test at 1373 K in an air furnace indicates that the LZ3Y coating has a lifetime of 617 cycles which is about 10% longer than that of LZ coating. The improvement of chemical homogeneity of the coating, the superior growth behavior of columns and the favorable mechanical properties are all very helpful to the prolongation of thermal cycling life of LZ3Y coating. The failure of LZ and LZ3Y coatings is mainly a result of the excess La{sub 2}O{sub 3}, the chemical incompatibility of ceramic coatings with TGO layer, the thermal expansion mismatch between ceramic coatings and bond coat, and the outward diffusion of alloying elements into the ceramic coatings.

Criteria for accurate determination of the magnon relaxation length from the nonlocal spin Seebeck effect

NARCIS (Netherlands)

Shan, Juan; Cornelissen, Ludo Johannes; Liu, Jing; Ben Youssef, J.; Liang, Lei; van Wees, Bart

2017-01-01

The nonlocal transport of thermally generated magnons not only unveils the underlying mechanism of the spin Seebeck effect, but also allows for the extraction of the magnon relaxation length (λm) in a magnetic material, the average distance over which thermal magnons can propagate. In this study, we

Demonstration of coal reburning for cyclone boiler NO{sub x} control. Appendix, Book 1

Energy Technology Data Exchange (ETDEWEB)

1994-06-01

Based on the industry need for a pilot-scale cyclone boiler simulator, Babcock Wilcox (B&W) designed, fabricated, and installed such a facility at its Alliance Research Center (ARC) in 1985. The project involved conversion of an existing pulverized coal-fired facility to be cyclone-firing capable. Additionally, convective section tube banks were installed in the upper furnace in order to simulate a typical boiler convection pass. The small boiler simulator (SBS) is designed to simulate most fireside aspects of full-size utility boilers such as combustion and flue gas emissions characteristics, fireside deposition, etc. Prior to the design of the pilot-scale cyclone boiler simulator, the various cyclone boiler types were reviewed in order to identify the inherent cyclone boiler design characteristics which are applicable to the majority of these boilers. The cyclone boiler characteristics that were reviewed include NO{sub x} emissions, furnace exit gas temperature (FEGT) carbon loss, and total furnace residence time. Previous pilot-scale cyclone-fired furnace experience identified the following concerns: (1) Operability of a small cyclone furnace (e.g., continuous slag tapping capability). (2) The optimum cyclone(s) configuration for the pilot-scale unit. (3) Compatibility of NO{sub x} levels, carbon burnout, cyclone ash carryover to the convection pass, cyclone temperature, furnace residence time, and FEGT.

Ferromagnetism in Fe{sub 3-x-y}Ni{sub x}GeTe{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Stahl, Juliane; Johrendt, Dirk [Muenchen Univ. (Germany). Dept. Chemie; Pomjakushin, Vladimir [Paul Scherrer Institute, Villigen (Switzerland). Lab. for Neutron Scattering

2016-07-01

Polycrystalline samples of Fe{sub 3-y}GeTe{sub 2} (0.08 ≤ y ≤ 0.29) and the solid solutions Fe{sub 3-x-y}Ni{sub x}GeTe{sub 2} (0.24 ≤ x ≤ 1.32; 0.14 ≤ y ≤ 0.41) were synthesized at 898-973 K in a resistance furnace and characterized by X-ray and neutron powder diffraction with Rietveld analysis (Fe{sub 3}GeTe{sub 2} type, P6{sub 3}/mmc, a = 402.665(3), c = 1632.820(14) pm for x = 0, y = 0.08). Fe{sub 3}Ge layers with planar FeGe hexagons and additional iron atoms above and below the rings are separated by double layers of tellurium atoms. Fe{sub 3}GeTe{sub 2} is ferromagnetic below T{sub C} = 230 K with magnetic moments aligned along the c axis. T{sub C} depends on the iron content and decreases with increasing iron vacancies continuously to 153 K in Fe{sub 2.71}GeTe{sub 2}. Further reduction of T{sub C} is possible by nickel substitution until magnetic ordering is nearly absent in Fe{sub 1.33}Ni{sub 1.32}GeTe{sub 2}. The suppression of the magnetic ordering is caused by random dilution of the magnetic iron atoms either by vacancies or by non-magnetic nickel atoms.

Mass Balance Modeling for Electric Arc Furnace and Ladle Furnace System in Steelmaking Facility in Turkey

Institute of Scientific and Technical Information of China (English)

(I)smail Ekmek(c)i; Ya(s)ar Yetisken; (U)nal (C)amdali

2007-01-01

In the electric arc furnace (EAF) steel production processes, scrap steel is principally used as a raw material instead of iron ore. In the steelmaking process with EAF, scrap is first melted in the furnace and then the desired chemical composition of the steel can be obtained in a special furnace such as ladle furnace (LF). This kind of furnace process is used for the secondary refining of alloy steel. LF furnace offers strong heating fluxes and enables precise temperature control, thereby allowing for the addition of desired amounts of various alloying elements. It also provides outstanding desulfurization at high-temperature treatment by reducing molten steel fluxes and removing deoxidation products. Elemental analysis with mass balance modeling is important to know the precise amount of required alloys for the LF input with respect to scrap composition. In present study, chemical reactions with mass conservation law in EAF and LF were modeled altogether as a whole system and chemical compositions of the final steel alloy output can be obtained precisely according to different scrap compositions, alloying elements ratios, and other input amounts. Besides, it was found that the mass efficiency for iron element in the system is 95.93%. These efficiencies are calculated for all input elements as 8.45% for C, 30.31% for Si, 46.36% for Mn, 30.64% for P, 41.96% for S, and 69.79% for Cr, etc. These efficiencies provide valuable ideas about the amount of the input materials that are vanished or combusted for 100 kg of each of the input materials in the EAF and LF system.

Fiscal 1976 Sunshine Project result report. Research on solar energy utilization systems (solar furnace); 1976 nendo taiyo energy riyo system chosa kenkyu seika hokokusho. Taiyoro

Energy Technology Data Exchange (ETDEWEB)

NONE

1977-03-01

For solar furnace, study was made on analysis of its use purpose, analysis of the profitability of large furnaces, safety, maintenance, solar radiation and construction site conditions. On production of fused refractories by solar furnace, in particular, giving attention on zircon sand and mullite, their fusion property was clarified, and their fine structure was obtained by rapid heating/cooling. On production of Si by solar furnace, in this fiscal year, in particular, study was made on the 1st step (production of coarse Si from silica rock) and 4th step (deposition of Si by decomposition of SiHCl{sub 3}). On study on high-temperature processing followed by chemical reaction, study was made on production of carborundum by solar furnace, its application to high-temperature gas reaction, and its application to heat storage by high-temperature chemical reaction. In addition, for large solar furnace, study was made on its maintenance, safety, pollution problem, and construction site condition based on estimation of direct solar radiation profile maps. Inlands of Tokai, Kii-Hanto and Seto-Naikai districts were confirmed to be suitable for solar furnaces. (NEDO)

Crystal growth of Li{sup 10}B{sub 3}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Akira [Kansai Research Establishment, Japan Atomic Energy Research Institute, Kizu, Kyoto (Japan); Gallagher, Hugh G.; Han, Thomas P.J.

1999-09-01

The growth of boron 10 isotope enriched L{sup 10}BO (Li{sup 10}B{sub 3}O{sub 5}) optical crystal has been developed from Top-Seeded-Solution-Growth using a resistance furnace. In the preparation for growth materials, we have made further improvement on a charge loading technique to a crucible and succeeded in forming suitable high temperature flux for producing crystals. Adequate temperature gradient of 1K/cm inside the crucible was achieved from searching for a combination of setting temperatures in the vertical three-zone furnace and installing a ceramic ring under the crucible. We have also optimized seed holder configuration and established growth conditions by several attempts. As a result, two good quality L{sup 10}BO crystals were produced with sizes of 14 x 25 x 22 mm and 13 x 10 x 12 mm from <001> oriented seed crystals. Although these sizes were limited by the size of the crucible used, appropriate oriented samples were extracted for detailed studies in optical measurements. (author)

Raman spectroscopic studies of Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} single crystals

Energy Technology Data Exchange (ETDEWEB)

Nithya, R., E-mail: nithya@igcar.gov.in; Ravindran, T. R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, TN (India); Daniel, D. J. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam-603110, TN (India)

2015-06-24

Single crystals of Nd{sub 1-x}Sm{sub x}GaO{sub 3} (x= 0 and 0.25) were grown by a four mirror IR image furnace using floating zone technique. The crystals are characterized by X-ray diffraction and Raman spectroscopic measurements. NGO adopts orthorhombic structure with Pbnm symmetry and samarium substituted compound also exhibited the same structure as that of the pristine compound without secondary phases. Polarized Raman spectra are measured at ambient temperature in a back scattering geometry. Spectra exhibit low intensity first-order Raman bands. In addition, several high intensity second-order Raman bands have been observed in the frequency range 2000 to 4000 cm{sup −1}.

Alternative fuels for multiple-hearth furnaces

Energy Technology Data Exchange (ETDEWEB)

Bracket, B D; Lawson, T U

1980-04-01

Results are described of a feasibility study on the use of refuse-derived fuel, shredded paper, wood waste, coal, and waste oil in multiple-hearth furnaces at the Lower Molonglo Water Quality Control Centre in Australia. An assessment of waste fuel availability and characteristics is given, and a summary is made of the technical and economic aspects of using these alternative fuels and of minimizing furnace fuel requirements by reducing sludge moisture. The recommended method of reducing fuel oil consumption in the furnace is shown to be sludge drying, using process exhaust heat in a rotary dryer.

Designing porous metallic glass compact enclosed with surface iron oxides

Energy Technology Data Exchange (ETDEWEB)

Cho, Jae Young; Park, Hae Jin; Hong, Sung Hwan; Kim, Jeong Tae; Kim, Young Seok; Park, Jun-Young; Lee, Naesung [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Seo, Yongho [Graphene Research Institute (GRI) & HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, Jin Man, E-mail: jinman_park@hotmail.com [Global Technology Center, Samsung Electronics Co., Ltd, 129 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-742 (Korea, Republic of); Kim, Ki Buem, E-mail: kbkim@sejong.ac.kr [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

2015-06-25

Highlights: • Porous metallic glass compact was developed using electro-discharge sintering process. • Uniform PMGC can only be achieved when low electrical input energy was applied. • Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. - Abstract: Porous metallic glass compact (PMGC) using electro-discharge sintering (EDS) process of gas atomized Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} metallic glass powder was developed. The formation of uniform PMGC can only be achieved when low electrical input energy was applied. Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. This finding suggests that PMGC can be applied in the new area such as catalyst via hydrothermal technique and offer a promising guideline for using the metallic glasses as a potential functional application.

Electrochemical characterization of V{sub x}Nb{sub y}C{sub z}/Bi{sub x}Ti{sub y}O{sub z} coatings produced through thermo-reactive diffusion and the sputtering technique

Energy Technology Data Exchange (ETDEWEB)

Castro H, S. A.; Alfonso, J. E.; Olaya, J. J., E-mail: jealfonso@unal.edu.co [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia de Materiales y Superficies, AA-14490 Bogota (Colombia)

2016-11-01

We present and experimental study of the structural evolution of a bilayer V{sub x}Nb{sub y}C{sub z}/Bi{sub x}Ti{sub y}O{sub z} coating produced via thermo-reactive diffusion (TRD) and the RF sputtering process on D-2 steel substrate. The TRD treatments were carried out in a molten mixture consisting of borax, ferro-niobium, ferro-vanadium, and aluminum, at 1313 K for 3 hours, using a resistance-heating furnace. Bi{sub x}Ti{sub y}O{sub z} coatings were deposited using RF magnetron sputtering on TRD coatings, in order to carry out a study of the corrosion behavior of this compound. The crystallographic structure of the coatings was determined via X-ray diffraction, the corrosion resistance was analyzed through the potentiodynamic polarization test (Tafel Extrapolation) and electrochemical impedance spectroscopic analysis (EIS). X-ray diffraction patterns showed that the ternary coating (VNbC{sub 2}) was preferentially oriented along the [200] direction with a cubic-centered face structure, and the Bi{sub x}Ti{sub y}O{sub z} coatings were amorphous. The electrochemical studies showed that the resistance corrosion of the coatings increased with respect to the bare substrate, and that polarization resistance in the bilayer coatings increased with respect to the ternary coatings, suggesting that the titanate has anti corrosive barrier effects. (Author)

Dynamics and control of a gas-fired furnace

NARCIS (Netherlands)

Roffel, B.; Rijnsdorp, J.E.

1974-01-01

A non-linear model has been developed for a gas-fired furnace in which oil is heated. The model is applicable from minimum to maximum heat load of the furnace. The dynamics of the model have been compared to experimental results, which were obtained for a pilot-scale furnace. They are in good

CO<sub>2sub> Problems and waste recycling. Research at the Institute of ferrous metallurgy

Directory of Open Access Journals (Sweden)

Gudenau, H. W.

2005-04-01

Full Text Available In a short introduction tests and calculations about CO<sub>2sub>-ice-blocs in the deep sea, use of CO<sub>2sub> for underground-coal-gasification and tertiary processes to increase oil-production by C02-flooding are shown. New activities are presented e.g. CO<sub>2sub>-injection into EAF combined with injection of coal, coke or directreduction-fines. After research of injection of coals, fine ores or dust into blast furnaces and other shaft furnaces activities are compared with injection of hot reducing gas generated by coal or waste gasification or top gas recycling combined with injection of fine solid fuels. Results of injection of prepared plastics (Duales System Deutschland, shredder-light-fraction from car-recycling and unburned carbon of power-station-ashes are discussed. Beside production of direct-reducediron by H<sub>2sub> fluidized reactor results of the reduction behavior ore/coal or dust/coal pellets or briquettes for the use in rotary hearth or modem shaft furnaces are shown

En una breve introducción se describen las pruebas y cálculos referentes a bloques de hielo de CO<sub>2sub> en el mar profundo, el uso del CO<sub>2sub> para la gasificación de carbón subterráneo y procesos terciarios para aumentar la producción de aceite por medio del torrente de CO<sub>2sub>. Dentro de las nuevas actividades se presentan, por ejemplo, la inyección de CO<sub>2sub> en el homo eléctrico de arco (HEA combinado con la inyección de carbón, coque o de finos de los procesos de reducción directa. Después de la investigación de la inyección de carbones, se comparan, por un lado, la inyección de los minerales finos o polvos en los hornos altos y otras actividades en los hornos de cuba con la inyección del gas reductor caliente generado por la gasificación del carbón o de los residuos o reciclado del gas del tragante combinado con la inyección de finos de combustibles sólidos. En el presente trabajo se discuten

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Tervola, K.; Haerkki, J.

1996-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquids temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) (14 refs.)

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Haerkki, J.; Tervola, K. [Oulu Univ. (Finland). Dept. of Process Engineering

1996-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

Acid slag injection into the blast furnace tuyere zone

Energy Technology Data Exchange (ETDEWEB)

Haerkki, J; Tervola, K [Oulu Univ. (Finland). Dept. of Process Engineering

1997-12-31

The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

The gold-rich indide Eu{sub 5}Au{sub 17.7}In{sub 4.3} and its relation with the structures of SrAu{sub 4.76}In{sub 1.24} and BaLi{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Muts, Ihor [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Ivan Franko National Univ. of Lviv (Ukraine). Inorganic Chemistry Dept.; Rodewald, Ute C.; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Zaremba, Vasyl' I.; Pavlosyuk, Orest [Ivan Franko National Univ. of Lviv (Ukraine). Inorganic Chemistry Dept.

2012-02-15

The gold-rich indide Eu{sub 5}Au{sub 17.7}In{sub 4.3} was synthesized from the elements in a sealed tantalum ampoule that was heated in a high-frequency furnace. Eu{sub 5}Au{sub 17.7}In{sub 4.3} crystallizes with a new monoclinic structure type: C2/m, a = 902.7(2), b = 722.8(3), c = 1734.1(4) pm, {beta} = 94.31(3) , wR2 = 0.0907, 2640 F{sup 2} values and 74 variables. Eu{sub 5}Au{sub 17.7}In{sub 4.3} has a pronounced gold substructure with Au.Au distances ranging from 278 to 300 pm. The striking structural motifs in the gold substructure are networks of Au6 hexagons and discrete units of corner- and edge-sharing Au{sub 4} tetrahedra. Eu{sub 5}Au{sub 17.70}In{sub 4.30} exhibits a small homogeneity range with In/Au mixing on two Wyckoff sites. Geometrically, the Eu{sub 5}Au{sub 17.7}In{sub 4.3} structure can be explained as an intergrowth variant of slightly distorted SrAu{sub 4.76}In{sub 1.24}- and BaLi{sub 4}-related slabs. The europium coordination in the BaLi{sub 4} slabs is similar to binary EuAu{sub 2}. (orig.)

Holden gas-fired furnace baseline data. Revision 1

International Nuclear Information System (INIS)

Weatherspoon, K.A.

1996-11-01

The Holden gas-fired furnace is used in the enriched uranium recovery process to dry and combust small batches of combustibles. The ash is further processed. The furnace operates by allowing a short natural gas flame to burn over the face of a wall of porous fire brick on two sides of the furnace. Each firing wall uses two main burners and a pilot burner to heat the porous fire brick to a luminous glow. Regulators and orifice valves are used to provide a minimum gas pressure of 4 in. water column at a rate of approximately 1,450 scf/h to the burners. The gas flow rate was calculated by determining the gas flow appropriate for the instrumentation in the gas line. Observed flame length and vendor literature were used to calculate pilot burner gas consumption. Air for combustion, purging, and cooling is supplied by a single blower. Rough calculations of the air-flow distribution in piping entering the furnace show that air flow to the burners approximately agrees with the calculated natural gas flow. A simple on/off control loop is used to maintain a temperature of 1,000 F in the furnace chamber. Hoods and glove boxes provide contamination control during furnace loading and unloading and ash handling. Fan EF-120 exhausts the hoods, glove boxes, and furnace through filters to Stack 33. A review of the furnace safety shows that safety is ensured by design, interlocks, procedure, and a safety system. Recommendations for safety improvements include installation of both a timed ignition system and a combustible-gas monitor near the furnace. Contamination control in the area could be improved by redesigning the loading hood face and replacing worn gaskets throughout the system. 33 refs., 16 figs

Material properties of the F82H melted in an electric arc furnace

Energy Technology Data Exchange (ETDEWEB)

Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp [Japan Atomic Energy Agency, Rokkasho, Aomori (Japan); Tanigawa, Hiroyasu [Japan Atomic Energy Agency, Rokkasho, Aomori (Japan); Kano, Sho; Abe, Hiroaki [Institute for Materials Research, Tohoku university, Sendai, Miyagi (Japan)

2015-10-15

Highlights: • We studied material properties of reduced activation ferritic/martensitic steel. • We melted F82H using a 20 tons electric arc furnace for the first time. • Mass effect likely affected material properties. • MX (M: Metal, C: Carbon and/or Nitrogen) precipitates mainly formed on grain and sub grain boundaries. - Abstract: Fusion DEMO reactor requires over 11,000 tons of reduced activation ferritic/martensitic steel. It is necessary to develop the manufacturing technology for fabricating such large-scale steel with appropriate mechanical properties. In this work, we focused fundamental mechanical properties and microstructures of F82H-BA12 heat which was melted using a 20 tons electric arc furnace followed by electroslag remelting process. Its raw material of iron was blast furnace iron, because the production volume of electrolytic iron which has been used in former heats, is limited. After melting and forging, this F82H-BA12 heat was heat-treated in four different conditions to consider their fluctuations and to optimize them, and tensile and Charpy impact tests were then performed. The result of these mechanical properties were comparable to those of former F82H heats less than 5 tons which were melted applying vacuum induction melting.

The use of blast furnace slag

Directory of Open Access Journals (Sweden)

V. Václavík

2012-10-01

Full Text Available The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

Furnace for treating bituminous material

Energy Technology Data Exchange (ETDEWEB)

Klotzer, M

1922-04-28

A furnace with saw-teeth-like profiled hearth, which by means of a kind of shaking slide executes a backward and forward motion, for carrying out the process according to Patent 422,391. It is characterized in that the stroke of the hearth moving in the furnace is smaller than the length of the profile tooth and the height of the feed is held less than the tooth height.

Ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb). Intergrowth structures with MgCu{sub 2} and CaCu{sub 5} related slabs

Energy Technology Data Exchange (ETDEWEB)

Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Oldenburg (Germany). Inst. fuer Chemie

2017-07-01

Fourteen ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce{sub 4}Rh{sub 9}Ga{sub 5}, Ce{sub 5}Rh{sub 12}Ga{sub 7}, Ce{sub 7}Rh{sub 18}Ga{sub 11}, Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)}, Nd{sub 4}Rh{sub 9}Ga{sub 5} and Gd{sub 4}Rh{sub 9}Ga{sub 5} were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE{sub 2+n} Rh{sub 3+3n} Ga{sub 1+2n} structure series in the Parthe intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu{sub 2} (Mg{sub 2}Ni{sub 3}Si as ternary variant) and CaCu{sub 5} (CeCo{sub 3}B{sub 2} as ternary variant). Only the Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)} crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y{sub 4}Rh{sub 9}Ga{sub 5} and Curie-Weiss paramagnetism for Gd{sub 4}Rh{sub 9}Ga{sub 5} and Tb{sub 4}Rh{sub 9}Ga{sub 5}. Low-temperature data show ferromagnetic ordering at T{sub C}=78.1 (Gd{sub 4}Rh{sub 9}Ga{sub 5}) and 55.8 K (Tb{sub 4}Rh{sub 9}Ga{sub 5}).

Effects of Li and Na intercalation on electronic, bonding and thermoelectric transport properties of MX{sub 2} (M = Ta; X = S or Se) dichalcogenides – Ab initio investigation

Energy Technology Data Exchange (ETDEWEB)

Meziane, Souheyr; Feraoun, Houda [Unité de Recherche Matériaux et Energies Renouvelables – URMER, Université de Tlemcen (Algeria); Ouahrani, Tarik [Laboratoire de Physique Théorique, Ecole Préparatoire en Sciences et Techniques, B.P. 230, 13000 Tlemcen (Algeria); Esling, Claude, E-mail: claude.esling@univ-lorraine.fr [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux, LEM3 UMR CNRS 7239, Université de Lorraine UL, Metz 57045 (France); Laboratoire d’Excellence “DAMAS”: Design of Metal Alloys for low-mAss Structures, Université de Lorraine – Metz, Ile du Saulcy, 57045 Metz Cedex 01 (France)

2013-12-25

Highlights: •Topological method is used to analyze the chemical bonding in Li(Na)TaX{sub 2} dichalcogenide compounds. •For the first time, Seebeck coefficient, electrical resistivity and thermal conductivity were estimated. •The best figure of merit is established for 2H-LiTaS{sub 2}. •Some new thermoelectric compounds are found. -- Abstract: Using the pseudo-potential method and semi-classical Boltzmann theory, electronic, chemical bonding and thermoelectric transport properties of sample and Li or Na intercalated Ta(S, Se){sub 2} dichalcogenides have been reported. The chemical bonding is studied using the Quantum Theory of Atoms in Molecules (QTAIM). Then, the Seebeck coefficient, electrical resistivity, electrical conductivity, thermal conductivity and figure of merit have been calculated in the temperature range 100–700 K. It was shown that the thermoelectric transport properties strongly depend on the Alkali metals doping and the two main structures 1T- or 2H- as well as the temperature. 2H-LiTaS{sub 2} have been selected as the best candidate for thermoelectrical applications with zT = 1.1.

Nitrogen oxide emissions from a kraft recovery furnace

International Nuclear Information System (INIS)

Prouty, A.L.; Stuart, R.C.; Caron, A.L.

1993-01-01

Nitrogen Oxide (NOx) emissions from a rebuilt kraft recovery furnace slightly exceeded the specified limit of 1.1 lb/ton (0.55 kg/metric ton) of black-liquor solids. Mill trials were undertaken to determine whether NOx emissions could be minimized by modifying furnace operation. NOx emissions increased when secondary air was shifted to tertiary ports. NOx emissions fell when the amounts of primary and total air were decreased, but this increased emissions of other pollutants. After demonstrating that best operation of the furnace could not meet the permit with an emissions limit that matched the furnace's performance at best operation

Titanium Powder Sintering in a Graphite Furnace and Mechanical Properties of Sintered Parts

Directory of Open Access Journals (Sweden)

Changzhou Yu

2017-02-01

Full Text Available Recent accreditation of titanium powder products for commercial aircraft applications marks a milestone in titanium powder metallurgy. Currently, powder metallurgical titanium production primarily relies on vacuum sintering. This work reported on the feasibility of powder sintering in a non-vacuum furnace and the tensile properties of the as-sintered Ti. Specifically, we investigated atmospheric sintering of commercially pure (C.P. titanium in a graphite furnace backfilled with argon and studied the effects of common contaminants (C, O, N on sintering densification of titanium. It is found that on the surface of the as-sintered titanium, a severely contaminated porous scale was formed and identified as titanium oxycarbonitride. Despite the porous surface, the sintered density in the sample interiors increased with increasing sintering temperature and holding time. Tensile specimens cut from different positions within a large sintered cylinder reveal different tensile properties, strongly dependent on the impurity level mainly carbon and oxygen. Depending on where the specimen is taken from the sintered compact, ultimate tensile strength varied from 300 to 580 MPa. An average tensile elongation of 5% to 7% was observed. Largely depending on the interstitial contents, the fracture modes from typical brittle intergranular fracture to typical ductile fracture.

Combined coal gasification and Fe{sub 3}O{sub 4}-reduction using high-temperature solar process heat

Energy Technology Data Exchange (ETDEWEB)

Tamaura, Y [Tokyo Inst. of Technology, Tokyo (Japan); Ehrensberger, K; Steinfeld, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

The coal/Fe{sub 3}O{sub 4} system was experimentally studied at PSI solar furnace. The reactants were directly exposed to a solar flux irradiation of 3,000 suns (1 sun = 1 kW/m{sup 2}). The combined gasification of coal and reduction of Fe{sub 2}O{sub 3} proceeded rapidly after only one second exposure, suggesting an efficient heat transfer and chemical conversion by direct solar energy absorption at the reaction site. The proposed solar thermochemical process offers the possibility of converting coal to a cleaner fluid fuel with a solar-upgraded calorific value. (author) 2 figs., 8 refs.

Method of operating a centrifugal plasma arc furnace

International Nuclear Information System (INIS)

Kujawa, S.T.; Battleson, D.M.; Rademacher, E.L. Jr.; Cashell, P.V.; Filius, K.D.; Flannery, P.A.; Whitworth, C.G.

1998-01-01

A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe 3 O 4 . Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe 2 O 3 . Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater. 3 figs

Waste and dust utilisation in shaft furnaces

Directory of Open Access Journals (Sweden)

Senk, D.

2005-12-01

Full Text Available Wastes and dusts from steel industry, non-ferrous metallurgy and other branches can be utilized e.g. in agglomeration processes (sintering, pelletizing or briquetting and by injection into shaft furnaces. This paper deals with the second way. Combustion and reduction behaviour of iron- and carbon-rich metallurgical dusts and sludges containing lead, zinc and alkali as well as other wastes with and without pulverized coal (PC has been studied when injecting into shaft furnaces. Following shaft furnaces have been examined: blast furnace, cupola furnace, OxiCup furnace and imperial-smelting furnace. Investigations have been done at laboratory and industrial scale. Some dusts and wastes under certain conditions can be not only reused but can also improve combustion efficiency at the tuyeres as well as furnace performance and productivity.

Los residuos y polvos de filtro provenientes de la industria siderúrgica, de la obtención de metales no ferrosos y de otras industrias, pueden ser utilizados, por ejemplo, en procesos de aglomeración como sintetizado, peletizado o briqueteado. En su caso, estos pueden ser inyectados en los hornos de cuba. Este artículo se enfoca a la inyección de estos materiales en los hornos de cuba. El comportamiento de la combustión y reducción de los polvos ricos en hierro y carbono y también lodos que contienen plomo, zinc y compuestos alcalinos y otros residuos con o sin carbón pulverizado (CP fue examinado, cuando se inyectaron en hornos de cuba. Los siguientes hornos de cuba fueron examinados: Horno alto, cubilote, OxiCup y horno de cuba Imperial Smelting. Las investigaciones se llevaron a cabo a escala de laboratorio e industrial. Algunos residuos y polvos bajo ciertas condiciones, no sólo pueden ser reciclados, sino también mejoran la eficiencia de combustión en las toberas, la operación y productividad del horno.

Edge-defect induced spin-dependent Seebeck effect and spin figure of merit in graphene nanoribbons.

Science.gov (United States)

Liu, Qing-Bo; Wu, Dan-Dan; Fu, Hua-Hua

2017-10-11

By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.

Process flow sheet evaluation of a nuclear hydrogen steelmaking plant applying very high temperature reactors for efficient steel production with less CO{sub 2} emissions

Energy Technology Data Exchange (ETDEWEB)

Kasahara, Seiji, E-mail: kasahara.seiji@jaea.go.jp; Inagaki, Yoshiyuki; Ogawa, Masuro

2014-05-01

Highlights: • CO{sub 2} emissions from a nuclear hydrogen steelmaking system was 13–21% of that from a blast furnace steelmaking system. • Heat input to shaft furnace in hydrogen steelmaking was large with much H{sub 2} consumption in the part. • Though hydrogen production thermal efficiency had influence on total heat input to hydrogen steelmaking, the effect on the CO{sub 2} emissions was small. • Steelmaking scale of a nuclear hydrogen steelamking plant with 2 VHTRs was a little smaller than that of the largest Midrex{sup ®} steelmaking plants. - Abstract: Recently, CO{sub 2} reduction is an important problem for steelmaking. Substitution of coal, presently used as a reducing agent of iron ore in blast furnaces, to hydrogen produced by non-fossil energy is a way to reduce CO{sub 2} emissions. In this study, the idea of nuclear hydrogen steelmaking (NHS) system was investigated using very high temperature reactor (VHTR) and thermochemical hydrogen production iodine–sulfur (IS) process. Heat input and CO{sub 2} emissions including material production, material transportation, and electricity generation were evaluation criteria. Results of the NHS system were compared with those of a conventional blast furnace steelmaking (BFS) system. Influence of heat input options to the steelmaking process and hydrogen production thermal efficiency of IS process were investigated for the NHS system. Though heat input to the NHS system was 130–142% of that to the BFS system, CO{sub 2} emissions of the system were 13–21%. Pre-heating of hydrogen by coal combustion before blowing to a shaft furnace was effective to decrease heat input, although CO{sub 2} emissions increased. Direct pre-heating by nuclear heat was also effective without increase of CO{sub 2} emissions if close location of the nuclear reactor to the steelmaking plant was publicly accepted. Hydrogen production thermal efficiency had a significant influence on the heat input. Conceptual design of a

Thermoelectric and spincaloric properties of epitaxial LaNiO{sub 3}/SrTiO{sub 3} superlattices from first principles

Energy Technology Data Exchange (ETDEWEB)

Geisler, Benjamin [FRM II, Technische Universitaet Muenchen, Garching (Germany); Fakultaet fuer Physik, Universitaet Duisburg-Essen, Duisburg (Germany); Blanca-Romero, Ariadna [Imperial College, London (United Kingdom); Pentcheva, Rossitza [Fakultaet fuer Physik, Universitaet Duisburg-Essen, Duisburg (Germany)

2016-07-01

Modern layer-by-layer fabrication techniques make it possible to grow epitaxial oxide superlattices with atomic precision. By combining accurate DFT+U calculations to determine the atomic and electronic structure and Boltzmann transport theory we show how a targeted design of the interface composition can be used to optimize the thermoelectric and/or spincaloric properties of LaNiO{sub 3}/SrTiO{sub 3}(001) superlattices. A TiO{sub 2}/LaO interface induces n-type doping, and a (potentially highly spin-polarized) charge current arises solely in-plane in the NiO{sub 2} layers. The out-of-plane resistance is high, since the SrTiO{sub 3} layers act as tunneling barriers. In contrast, a NiO{sub 2}/SrO interface leads to p-type doping. In this case, also the valence band of SrTiO{sub 3} contributes to the transmission, thereby reducing the out-of-plane resistance significantly. Besides this doping effect we find that the interface composition influences the electronic band structure, which leads to a nontrivial behavior of the Seebeck coefficient. Funding by the DFG within TRR 80 (G3 and G8) is acknowledged.

Multiple hearth furnace for reducing iron oxide

Science.gov (United States)

Brandon, Mark M [Charlotte, NC; True, Bradford G [Charlotte, NC

2012-03-13

A multiple moving hearth furnace (10) having a furnace housing (11) with at least two moving hearths (20) positioned laterally within the furnace housing, the hearths moving in opposite directions and each moving hearth (20) capable of being charged with at least one layer of iron oxide and carbon bearing material at one end, and being capable of discharging reduced material at the other end. A heat insulating partition (92) is positioned between adjacent moving hearths of at least portions of the conversion zones (13), and is capable of communicating gases between the atmospheres of the conversion zones of adjacent moving hearths. A drying/preheat zone (12), a conversion zone (13), and optionally a cooling zone (15) are sequentially positioned along each moving hearth (30) in the furnace housing (11).

Numerical study of furnace process of a 600 MW pulverized coal boiler under low load with SNCR application

Energy Technology Data Exchange (ETDEWEB)

Cao, Q.X.; Shi, Y.; Liu, H.; Yang, C.H.; Wu, S.H. [Harbin Institute of Technology, Harbin (China)

2013-07-01

Numerical simulation of flow, heat transfer, and combustion process in a 600MW pulverized coal boiler under low load is performed using Computational Fluid Dynamics (CFD) code Fluent. The distributions of temperature and species were obtained and their influences on Selective non-catalytic reduction (SNCR) were analyzed. The results indicate that the furnace temperature changed significantly as the operation load declines. The furnace space with proper temperature for SNCR reaction becomes lower with decreasing of operation load. As the load falls off, the available O{sub 2}concentration for SNCR reactions rises gently and the initial NOx concentration for SNCR reactions debases slightly. These variations can have some influence on the SNCR process. For the upper furnace where the temperature is suitable for SNCR reactions, the CO concentration is close to 0 under different load. Consequently, the SNCR process will not be affected by CO based on the calculation in this work.

System and method for making metallic iron with reduced CO.sub.2 emissions

Science.gov (United States)

Kiesel, Richard F; Englund, David J; Schlichting, Mark; Meehan, John; Crouch, Jeremiah; Wilson, Logan

2014-10-14

A method and system for making metallic iron nodules with reduced CO.sub.2 emissions is disclosed. The method includes: assembling a linear hearth furnace having entry and exit portions, at least a conversion zone and a fusion zone, and a moving hearth adapted to move reducible iron bearing material through the furnace on contiguous hearth sections; assembling a shrouded return substantially free of air ingress extending adjacent at least the conversion and fusion zones of the furnace through which hearth sections can move from adjacent the exit portion to adjacent the entry portion of the furnace; transferring the hearth sections from the furnace to the shrouded return adjacent the exit portion; reducing reducible material in the linear hearth furnace to metallic iron nodules; and transporting gases from at least the fusion zone to the shrouded return to heat the hearth sections while in the shrouded return.

Enhanced thermoelectric performance with participation of F-electrons in β-Zn{sub 4}Sb{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu, Mian; Qin, Xiaoying, E-mail: xyqin@issp.ac.cn; Liu, Changsong; Li, Xiyu; Yang, Xiuhui

2014-01-25

Highlights: • Find an effective route to enhance the thermoelectric figure of merit of β-Zn{sub 4}Sb{sub 3}. • Provide the corresponding theoretical predictions. • Investigated the effects of doping Ce and Pr in β-Zn{sub 4}Sb{sub 3}. -- Abstract: The effects of rare-earth element impurities Ce and Pr on the electronic structure and thermoelectric properties of β-Zn{sub 4}Sb{sub 3} were investigated by performing self-consistent ab initio electronic structure calculations within density functional theory and solving the Boltzmann transport equations within the relaxation time approximation. The results demonstrated that these rare-earth element impurities with f orbitals could introduce giant sharp resonant peaks in the density of states (DOS) near the host valence band maximum in energy. And these deliberately engineered DOS peaks result in a sharp increase of the room-temperature Seebeck coefficient and power factor from those of impurity-free system by a factor of 100 and 22, respectively. Additionally, with the simultaneous declining of carrier thermal conductivity, a potential 5-fold increase at least with Ce doping and more than 3 times increase with Pr doping in the thermoelectric figure of merit of β-Zn{sub 4}Sb{sub 3} at room temperature are achieved. The effective DOS restructuring strategy opens up new opportunities for thermoelectric power generation and waste heat recovery at large scale.

Modeling compaction-induced energy dissipation of granular HMX

Energy Technology Data Exchange (ETDEWEB)

Gonthier, K.A. [Lamar Univ., Beaumont, TX (US). Dept. of Mechanical Engineering; Menikoff, R.; Son, S.F.; Asay, B.W. [Los Alamos National Lab., NM (US)

1998-12-31

A thermodynamically consistent model is developed for the compaction of granular solids. The model is an extension of the single phase limit of two-phase continuum models used to describe Deflagration-to-Detonation Transition (DDT) experiments. The focus is on the energetics and dissipation of the compaction process. Changes in volume fraction are partitioned into reversible and irreversible components. Unlike conventional DDT models, the model is applicable from the quasi-static to dynamic compaction regimes for elastic, plastic, or brittle materials. When applied to the compaction of granular HMX (a brittle material), the model predicts results commensurate with experiments including stress relaxation, hysteresis, and energy dissipation. The model provides a suitable starting point for the development of thermal energy localization sub-scale models based on compaction-induced dissipation.

Hot corrosion of the ceramic composite coating Ni{sub 3}Al-Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3}/MgO plasma sprayed on 316L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Shirazi, Amir Khodaparast; Kiahosseini, Seyed Rahim [Islamic Azad Univ., Damghan (Iran, Islamic Republic of). Dept. of Engineering

2017-08-15

Ni{sub 3}Al-Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3}/MgO three-layered coatings with thicknesses of 50, 100, and 150 μm for Al{sub 2}O{sub 3}/MgO and 100 μm for the other layers were deposited on 316L stainless steel using plasma spraying. X-ray diffraction, atomic force microscopy, furnace hot corrosion testing in the presence of a mixture of Na{sub 2}SO{sub 4} and V{sub 2}O{sub 5} corrosive salts and scanning electron microscopy were used to determine the structural, morphological and hot corrosion resistance of samples. Results revealed that the crystalline grains of MgO and Al{sub 2}O{sub 3} coating were very small. Weight loss due to hot corrosion decreased from approximately 4.267 g for 316L stainless steel without coating to 2.058 g. The samples with 150 μm outer coating showed improved resistance with the increase in outer layer thickness. Scanning electron microscopy of the coated surface revealed that the coating's resistance to hot corrosion is related to the thickness and the grain size of Al{sub 2}O{sub 3}/MgO coatings.

Application of Carbon Composite Bricks for Blast Furnace Hearth

Science.gov (United States)

Zuo, Haibin; Wang, Cong; Zhang, Jianliang; Zhao, Yongan; Jiao, Kexin

Traditional refractory materials for blast furnace hearth lining are mainly composed of carbon bricks and the ceramic cup. However, these materials can't meet the demands for long service life design of blast furnaces. In this paper, a new refractory called carbon composite brick (CCB) was introduced, which combined the advantages of carbon bricks and the ceramic cup. In this case, the resistance of the CCB against corrosion was equal to the ceramic cup and the thermal conductivity of the CCB was equal to carbon bricks. From the results of more than 20 blast furnaces, the CCB could be well used in small blast furnaces and large blast furnaces. In the bad condition of low grade burden and high smelting intensity, the CCB gave full play to the role of cooling system, and effectively resisted the erosion of hot metal to improve the service life of blast furnaces.

Predictive control of thermal state of blast furnace

Science.gov (United States)

Barbasova, T. A.; Filimonova, A. A.

2018-05-01

The work describes the structure of the model for predictive control of the thermal state of a blast furnace. The proposed model contains the following input parameters: coke rate; theoretical combustion temperature, comprising: natural gas consumption, blasting temperature, humidity, oxygen, blast furnace cooling water; blast furnace gas utilization rate. The output parameter is the cast iron temperature. The results for determining the cast iron temperature were obtained following the identification using the Hammerstein-Wiener model. The result of solving the cast iron temperature stabilization problem was provided for the calculated values of process parameters of the target area of the respective blast furnace operation mode.

Project of compact accelerator for cancer proton therapy

International Nuclear Information System (INIS)

Picardi, L.; Ronsivalle, C.; Vignati, A.

1995-04-01

The status of the sub-projetc 'Compact Accelerator' in the framework of the Hadrontherapy Project leaded by Prof. Amaldi is described. Emphasis is given to the reasons of the use of protons for radiotherapy applications, to the results of the preliminary design studies of four types of accelerators as possible radiotherapy dedicated 'Compact Accelerator' and to the scenario of the fonts of financial resources

The fate of injectant coal in blast furnaces: The origin of extractable materials of high molecular mass in blast furnace carryover dusts

Energy Technology Data Exchange (ETDEWEB)

Dong, S.N.; Wu, L.; Paterson, N.; Herod, A.A.; Dugwell, D.R.; Kandiyoti, R. [University of London Imperial College of Science & Technology, London (United Kingdom). Dept. of Chemical Engineering

2005-07-01

The aim of the work was to investigate the fate of injectant coal in blast furnaces and the origin of extractable materials in blast furnace carryover dusts. Two sets of samples including injectant coal and the corresponding carryover dusts from a full sized blast furnace and a pilot scale rig have been examined. The samples were extracted using 1-methyl-2-pyrrolidinone (NMP) solvent and the extracts studied by size exclusion chromatography (SEC). The blast furnace carryover dust extracts contained high molecular weight carbonaceous material, of apparent mass corresponding to 10{sup 7}-10{sup 8} u, by polystyrene calibration. In contrast, the feed coke and char prepared in a wire mesh reactor under high temperature conditions did not give any extractable material. Meanwhile, controlled combustion experiments in a high-pressure wire mesh reactor suggest that the extent of combustion of injectant coal in the blast furnace tuyeres and raceways is limited by time of exposure and very low oxygen concentration. It is thus likely that the extractable, soot-like material in the blast furnace dust originated in tars is released by the injectant coal. Our results suggest that the unburned tars were thermally altered during the upward path within the furnace, giving rise to the formation of heavy molecular weight (soot-like) materials.

Imaging of electric transport mechanisms in a ferromagnetic Ga{sub 0.96}Mn{sub 0.04}As thin film by low-temperature scanning laser microscopy

Energy Technology Data Exchange (ETDEWEB)

Tomaschko, Jochen; Guenon, Stefan; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut - Experimentalphysik II, Universitaet Tuebingen (Germany); Goennenwein, Sebastian T.B.; Brandlmaier, Andreas; Althammer, Matthias [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Schoch, Wladimir; Limmer, Wolfgang [Institut fuer Halbleiterphysik, Universitaet Ulm (Germany)

2008-07-01

Due to its possible applications in spintronic devices the diluted magnetic semiconductor (DMS) Ga{sub 1-x}Mn{sub x}As has been the subject of intense research. Integral measurements revealed an anisotropic magnetoresistance (AMR) and magnetothermopower (AMTP). Thus, both resistivity and thermopower depend on the orientation of magnetization. By examining a 250 nm thick epitaxially grown Ga{sub 0.96}Mn{sub 0.04}As Hall-bar with scanning laser microscopy these two quantities (more precisely the bolometric signal dR/dT and the Seebeck-coefficient S{sub xx}) could be imaged at temperatures down to 3 K with a spatial resolution of {proportional_to}1 {mu}m. We developed simple models to describe these signals and identified them as electric dipole and monopole plus quadrupole signals, respectively. Efforts to image ferromagnetic domains have been made. Furthermore, we discovered inhomogeneities, not visible with conventional optical microscopy and observed a signal possibly due to the diffusion of electron-hole-pairs created by the laser spot.

Particle morphology and magnetic properties of Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12}O{sub 19} powder calcined conventionally and by microwave heating

Energy Technology Data Exchange (ETDEWEB)

Kanagesan, S., E-mail: kanagu1980@gmail.com [Materials Synthesis and Characterization Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang 43400, Selangor (Malaysia); Hashim, M. [Materials Synthesis and Characterization Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang 43400, Selangor (Malaysia); Physics Department, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor (Malaysia); Jesurani, S. [Department of Physics, Jeyaraj Annapackium College for Women, Periyakulam 625601, Tamil Nadu (India); Kalaivani, T. [Center for material science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Ismail, I.; Shafie, M.S.E. [Materials Synthesis and Characterization Laboratory (MSCL), Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang 43400, Selangor (Malaysia)

2012-12-05

Highlights: Black-Right-Pointing-Pointer Synthesis of Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12}O{sub 19} by sol-gel technique. Black-Right-Pointing-Pointer Crystallization temperature is reduced to 900 Degree-Sign C due to the addition of D-Fructose. Black-Right-Pointing-Pointer Results of conventional and microwave calcined samples are reported. - Abstract: Barium strontium hexaferrite (Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12}O{sub 19}-BSF) has been prepared by sol-gel process involving use of D-Fructose as a fuel. The prepared precursor was calcined in two different calcinations techniques conventional and microwave furnace. X-ray powder diffraction studies confirmed the formation of single phase Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12}O{sub 19}. HR-SEM results show the morphology of the particles is hexagonal structures in platelet form. The average particle size of conventionally calcined BSF powder is 100-250 nm and that of microwave calcined powder is 30-100 nm. The broad hysteresis loop reveals that powder is well crystallized and exhibits hard magnetic properties.

High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases

Energy Technology Data Exchange (ETDEWEB)

Madar, Naor; Givon, Tom; Mogilyansky, Dmitry; Gelbstein, Yaniv [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

2016-07-21

In an attempt to reduce our reliance on fossil fuels, associated with severe environmental effects, the current research is focused on the identification of the thermoelectric potential of p-type (GeTe){sub 1−x}(Bi{sub 2}Te{sub 3}){sub x} alloys, with x values of up to 20%. Higher solubility limit of Bi{sub 2}Te{sub 3} in GeTe, than previously reported, was identified around ∼9%, extending the doping potential of GeTe by the Bi{sub 2}Te{sub 3} donor dopant, for an effective compensation of the high inherent hole concentration of GeTe toward thermoelectrically optimal values. Around the solubility limit of 9%, an electronic optimization resulted in an impressive maximal thermoelectric figure of merit, ZT, of ∼1.55 at ∼410 °C, which is one of the highest ever reported for any p-type GeTe-rich alloys. Beyond the solubility limit, a Fermi Level Pinning effect of stabilizing the Seebeck coefficient was observed in the x = 12%–17% range, leading to stabilization of the maximal ZTs over an extended temperature range; an effect that was associated with the potential of the governed highly symmetric Ge{sub 8}Bi{sub 2}Te{sub 11} and Ge{sub 4}Bi{sub 2}Te{sub 7} phases to create high valence band degeneracy with several bands and multiple hole pockets on the Fermi surface. At this compositional range, co-doping with additional dopants, creating shallow impurity levels (in contrast to the deep lying level created by Bi{sub 2}Te{sub 3}), was suggested for further electronic optimization of the thermoelectric properties.

Low cost thermoelectric module

Energy Technology Data Exchange (ETDEWEB)

Kumpeerapun, T.; Hirunlabh, J. [King Mongkut Univ. of Technology, Bangkok (Thailand); Zeghmati, B. [Perpignan Univ., Perpignan (France). Faculty of Sciences; Scherrer, H.; Dauscher, A.; Weber, S.; Jahed, H.M.; Lernoir, B.; Kosalathip, V. [Ecole des Mines, Nancy (France). Laboratoire de Physique des Materiaux; Khedari, J. [South-East Asia Univ., Bangkok (Thailand). Faculty of Engineering

2006-07-01

The properties of a bismuth-telluride-antimony (Bi{sub x}Sb{sub 2-8}Te{sub 3}) polycrystalline thermoelectric material prepared using a novel melting and hot pressing process were investigated. The aim of the study was to synthesize the materials without the need for doping. Materials were weighed and placed in a quartz tube, which was sealed under vacuum and heated in a rocking furnace from room temperature to 750 degrees C over a period of 1 hour. Temperatures were maintained at 750 degrees C for a further 2 hours. The sample was then removed from the furnace and suddenly quenched in water. The ingot was then crushed into a powder using an agate mortar and sieved. Samples exhibiting a cylindrical shape were reserved. Samples were then examined using scanning electron microscopy (SEM) to determine their morphology and homogeneity. A sample pellet was then prepared for thermal conductivity measurements at room temperature. the pellet was nickel-plated on both sides and stacked between circular copper disks with thermocouples. Data were collected when the system reached thermal equilibrium. The Seebeck coefficient was measured by applying a small temperature difference. Results showed that the process effectively transformed the base materials into an alloy. It was concluded that the hot pressing successfully synthesized the materials. 6 refs., 1 tab., 6 figs.

Operation of a semi-industrial unit for the production of UO sub(3)

International Nuclear Information System (INIS)

Baba, S.

1982-01-01

This work discusses the precipitation of ammonium diuranate (ADU) from uranyl nitrate using ammonia gas as precipitant, its filtration, dewatering and conversion to nuclear grade uranium trioxide. The ADU was filtered using a rotary drum filter and dried into a continuous belt conveyor tunnel furnace. Experiments were made to found suitable technological conditions to obtain UO sub(3) with chemical and mechanical characteristics appropriated to feed the UF sub(4) Pilot Plant. To reach this aim the following parameters were studied:- uranyl nitrate concentration, precipitation temperature, residence time and final PH of the ADU pulp; filter element characteristics, rotation speed and vacuum distribution in the rotary drum filter; residence time, temperature and water content of UO sub(3) in the continuous belt conveyor tunnel furnace. The best operational conditions recommended are: uranyl nitrate concentration: 100 g U/L, ADU PH precipitation: 9, temperature of the pulp inside the reactor 60-85 sup(0) C, residence time: 40 minutes; ADU pulp concentration: 100 g U/L; temperature of ADU in the filter: 30-60 sup(0) C; PH of the ADU pulp in the filter: 9; rotation speed: 0,072-0,090 rpm; vacuum conditions: 15-24 inches Hg column; residence time of ADU/UO sub(3) cake in the furnace: 4 hours. (author)

Thermoelectric properties of doped BaHfO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Dixit, Chandra Kr., E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com [Dept. of Physics, Dr. Shakuntala Misra National Rehabilitation University, Lucknow-229001, U.P India (India); Bhamu, K. C. [Department of Physics, Goa University, Goa-403 206 (India); Sharma, Ramesh, E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com [Dept. of Physics, Feroze Gandhi Institute of Engineering & Technology, Raebareli-229001, U.P India (India)

2016-05-06

We have studied the structural stability, electronic structure, optical properties and thermoelectric properties of doped BaHfO{sub 3} by full potential linearized augmented plane wave (FP-LAPW) method. The electronic structure of BaHfO{sub 3} doped with Sr shows enhances the indirect band gaps of 3.53 eV, 3.58 eV. The charge density plots show strong ionic bonding in Ba-Hf, and ionic and covalent bonding between Hf and O. Calculations of the optical spectra, viz., the dielectric function, refractive index and extinction coefficient are performed for the energy range are calculated and analyzed. Thermoelectric properties of semi conducting are also reported first time. The doped BaHfO{sub 3} is approximately wide band gap semiconductor with the large p-type Seebeck coefficient. The power factor of BaHfO{sub 3} is increased with Sr doping, decreases because of low electrical resistivity and thermal conductivity.

BPM Motors in Residential Gas Furnaces: What are the Savings?

OpenAIRE

Lutz, James; Franco, Victor; Lekov, Alex; Wong-Parodi, Gabrielle

2006-01-01

Residential gas furnaces contain blowers to distribute warm air. Currently, furnace blowers use either a Permanent Split Capacitor (PSC) or a Brushless Permanent Magnet (BPM) motor. Blowers account for the majority of furnace electricity consumption. Therefore, accurate determination of the blower electricity consumption is important for understanding electricity consumption of furnaces. The electricity consumption of blower motors depends on the static pressure across the blower. This p...

Triangular Zn{sub 3} and Ga{sub 3} units in Sr{sub 2}Au{sub 6}Zn{sub 3}, Eu{sub 2}Au{sub 6}Zn{sub 3}, Sr{sub 2}Au{sub 6}Ga{sub 3}, and Eu{sub 2}Au{sub 6}Ga{sub 3}. Structure, magnetism, {sup 151}Eu Moessbauer and {sup 69;71}Ga solid state NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gerke, Birgit; Niehaus, Oliver; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Korthaus, Alexander; Haarmann, Frank [RWTH Aachen Univ. (Germany). Inst. fuer Anorganische Chemie

2016-08-01

The gold-rich intermetallic compounds Sr{sub 2}Au{sub 6}Zn{sub 3}, Eu{sub 2}Au{sub 6}Zn{sub 3}, Sr{sub 2}Au{sub 6}Ga{sub 3}, and Eu{sub 2}Au{sub 6}Ga{sub 3} were synthesized from the elements in sealed tantalum ampoules in induction or muffle furnaces. The europium compounds are reported for the first time and their structures were refined from single crystal X-ray diffractometer data: Sr{sub 2}Au{sub 6}Zn{sub 3} type, R anti 3c, a = 837.7(1), c = 2184.5(4) pm, wR2 = 0.0293, 572 F{sup 2} values for Eu{sub 2}Au{sub 6.04}Zn{sub 2.96} and a = 838.1(2), c = 2191.7(5) pm, wR2 = 0.0443, 513 F{sup 2} values for Eu{sub 2}Au{sub 6.07}Ga{sub 2.93} with 20 variables per refinement. The structures consist of a three-dimensional gold network with a 6R stacking sequence, similar to the respective diamond polytype. The cavities of the network are filled in a ratio of 2:1 by strontium (europium) atoms and Ga{sub 3} (Zn{sub 3}) triangles in an ordered manner. Sr{sub 2}Au{sub 6}Zn{sub 3} and Sr{sub 2}Au{sub 6}Ga{sub 3} are diamagnetic with room temperature susceptibilities of -3.5 x 10{sup -4} emu mol{sup -1}. Temperature dependent susceptibility and {sup 151}Eu Moessbauer spectroscopic measurements show a stable divalent ground state for both europium compounds. Eu{sub 2}Au{sub 6}Zn{sub 3} and Eu{sub 2}Au{sub 6}Ga{sub 3} order antiferromagnetically below Neel temperatures of 16.3 and 12.1 K, respectively. Anisotropic electrical conductivity of Sr{sub 2}Au{sub 6}Ga{sub 3} is proven by an alignment of the crystallites in the magnetic field. Orientation-dependent {sup 69;71}Ga NMR experiments combined with quantum mechanical calculations (QM) give evidence for a highly anisotropic charge distribution of the Ga atoms.

Programmable temperature regulator of VAO-1 furnace

International Nuclear Information System (INIS)

Zahalka, F.

1979-01-01

A programmable temperature controller is described for a furnace for high-level waste processing. Furnace temperature is controlled by a program compiled from a combination of 3 parts with different linear increments or decrements of time dependent temperature and 2 parts with isothermal control for over a preset period. The equipment consists essentially of a programming unit, a programmed digital-to-analog converter and a power unit. The design is described in detail and its specifications are given. The maximum operating temperature of 1500 degC may be reached in the furnace charge section. (B.S.)

Electric melting furnace for waste solidification

International Nuclear Information System (INIS)

Masaki, Toshio.

1990-01-01

To avoid electric troubles or reduction of waste processing performance even when platinum group elements are contained in wastes to be applied with glass solidification. For this purpose, a side electrode is disposed to the side wall of a melting vessel and a central electrode serving as a counter electrode is disposed about at the center inside the melting vessel. With such a constitution, if conductive materials are deposited at the bottom of the furnace or the bottom of the melting vessel, heating currents flow selectively between the side electrode and the central electrode. Accordingly, no electric currents flow through the conductive deposits thereby enabling to prevent abnormal heating in the bottom of the furnace. Further, heat generated by electric supply between the side electrode and the central electrode is supplied efficiently to raw material on the surface of the molten glass liquid to improve the processing performance. Further, disposition of the bottom electrode at the bottom of the furnace enables current supply between the central electrode and the bottom electrode to facilitate the temperature control for the molten glass in the furnace than in the conventional structure. (I.S.)

Massive injection of coal and superoxygenated blast into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Toxopeus, H.L.; Danloy, G.; Franssen, R.; Havelange, O. [Corus, IJmuiden (Netherlands)

2002-07-01

The aim of the present project was to demonstrate the industrial feasibility of a massive injection of coal, {+-}270 kg/tHM, combined with a high O{sub 2} enrichment of the blast. The coke rate would thus be reduced to well below 250 kg/tHM. A reference level of 200-220 kg coal/tHM was successfully accomplished. However, the technical condition of the blast furnace hearths overruled all ambitions, the anticipated trial scheme had to be abandoned and no further trials were performed. A very short trial was aborted shortly after reaching an injection level of around 265 coal/tHM, due to excessive generation of very fine sludge originating from incomplete combustion. This forced the operators to investigate the merits of combustion more in depth. At the aimed low coke-rate detailed information about the gas distribution is of utmost importance. Therefore, in conjunction with the industrial tests, CRM designed a gas tracing method. Measurement of the transfer time between the injection point (a tuyere) and the sampling points (on an above-burden probe) would allow deduction of the radial gas distribution. CRM made the design and the start-up of an installation built by Hoogovens on blast furnace 7 of IJmuiden. Since then, repeated measurements have shown that the gas transfer time profiles are consistent with the data measured at the blast furnace top and at the wall. The modifications of the moveable armour position are reflected better and faster on the gas distribution as measured by helium tracing than on the skin flow temperatures.

Synthesize and microstructure characterization of Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} Heusler alloy

Energy Technology Data Exchange (ETDEWEB)

Elwindari, Nastiti; Manaf, Azwar, E-mail: azwar@ui.ac.id [Physics Department, Faculty of Science, Universitas Indonesia, Depok 16424 (Indonesia)

2016-06-17

The ferromagnetic heusler alloys are promising materials in many technical applications due to their multifunctional properties such as shape memory effect, magnetocaloric effect, giant magnetoresistance, etc. In this work, synthesize and characterization of polycrystalline Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} (NMCS) alloy are reported. Alloy preparation was conducted by melting the constitute elements under an innert Argon (Ar) atmosphere in a vacuum mini arc-melting furnace. Homogenization of the microstructure of the as-cast ingot was obtained after annealing process at 750°C for 48 hours. It is shown that the dendrites structure has changed to equaixed grains morphology after homogenization. Microstructure characteristics of material by x-ray diffraction revealed that the alloy has a L{sub 21}-type cubic crystal structure as the main phase at room temperature. In order to induce the shape anisotropy, a forging treatment was applied to show the shape orientation of material. Various enhancements of magnetic properties in a longitudinal direction were observed at various degree of anisotropy. The microstructure changes of as-cast NMCS and effects of homogenization treatments as studied by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) are discussed in details.

Bulk magnon spin current theory for the longitudinal spin Seebeck effect

Energy Technology Data Exchange (ETDEWEB)

Rezende, S.M., E-mail: rezende@df.ufpe.br [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil); Rodríguez-Suárez, R.L. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil); Facultad de Física, Pontificia Universidad Católica de Chile, Casilla, 306 Santiago (Chile); Cunha, R.O.; López Ortiz, J.C.; Azevedo, A. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, Pernambuco (Brazil)

2016-02-15

The longitudinal spin Seebeck effect (LSSE) consists in the generation of a spin current parallel to a temperature gradient applied across the thickness of a bilayer made of a ferromagnetic insulator (FMI), such as yttrium iron garnet (YIG), and a metallic layer (ML) with strong spin orbit coupling, such as platinum. The LSSE is usually detected by a DC voltage generated along the ML due to the conversion of the spin current into a charge current perpendicular to the static magnetic field by means of the inverse spin Hall effect. Here we present a model for the LSSE that relies on the bulk magnon spin current created by the temperature gradient across the thickness of the FMI. We show that the spin current pumped into the metallic layer by the magnon accumulation in the FMI provides continuity of the spin current at the FMI/ML interface and is essential for the existence of the LSSE. The results of the theory are in good agreement with experimental LSSE data in YIG/Pt bilayers on the variation of the DC voltage with the sample temperature, with the FMI layer thickness and with the intensity of high magnetic fields. - Highlights: • We present a theory for the longitudinal spin Seebeck effect based on bulk magnons. • The model explains quantitatively the measured voltage in YIG/Pt created by the LSSE. • The model explains quantitatively the temperature dependence of LSSE measured in YIG/Pt. • The model agrees qualitatively with the measured dependence of LSSE with YIG thickness. • The model agrees qualitatively with the measured dependence of LSSE on magnetic field.

Stationary bound-state massive scalar field configurations supported by spherically symmetric compact reflecting stars

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

2017-12-15

It has recently been demonstrated that asymptotically flat neutral reflecting stars are characterized by an intriguing no-hair property. In particular, it has been proved that these horizonless compact objects cannot support spatially regular static matter configurations made of scalar (spin-0) fields, vector (spin-1) fields and tensor (spin-2) fields. In the present paper we shall explicitly prove that spherically symmetric compact reflecting stars can support stationary (rather than static) bound-state massive scalar fields in their exterior spacetime regions. To this end, we solve analytically the Klein-Gordon wave equation for a linearized scalar field of mass μ and proper frequency ω in the curved background of a spherically symmetric compact reflecting star of mass M and radius R{sub s}. It is proved that the regime of existence of these stationary composed star-field configurations is characterized by the simple inequalities 1 - 2M/R{sub s} < (ω/μ){sup 2} < 1. Interestingly, in the regime M/R{sub s} << 1 of weakly self-gravitating stars we derive a remarkably compact analytical equation for the discrete spectrum {ω(M,R_s, μ)}{sup n=∞}{sub n=1} of resonant oscillation frequencies which characterize the stationary composed compact-reflecting-star-linearized-massive-scalar-field configurations. Finally, we verify the accuracy of the analytically derived resonance formula of the composed star-field configurations with direct numerical computations. (orig.)

Relativistic modeling of compact stars for anisotropic matter distribution

Energy Technology Data Exchange (ETDEWEB)

Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman)

2017-05-15

In this paper we have solved Einstein's field equations of spherically symmetric spacetime for anisotropic matter distribution by assuming physically valid expressions of the metric function e{sup λ} and radial pressure (p{sub r}). Next we have discussed the physical properties of the model in details by taking the radial pressure p{sub r} equal to zero at the boundary of the star. The physical analysis of the star indicates that its model parameters such as density, redshift, radial pressure, transverse pressure and anisotropy are well behaved. Also we have obtained the mass and radius of our compact star which are 2.29M {sub CircleDot} and 11.02 km, respectively. It is observed that the model obtained here for compact stars is compatible with the mass and radius of the strange star PSR 1937 +21. (orig.)

Investigation of the transport properties and compositions of the Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} series (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi)

Energy Technology Data Exchange (ETDEWEB)

Forbes, Scott [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Yuan, Fang [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kosuda, Kosuke; Kolodiazhnyi, Taras [Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

2016-10-15

The Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi) were successfully prepared from high temperature reactions at 1225–1300 °C. These phases maintain the same structure types as the parent RE{sub 9}Pn{sub 5}O{sub 5} phases, except for a Ca/RE mixing. The study and preparation of these phases was motivated by the desire to shift the metallic type properties of the parent RE{sub 9}Pn{sub 5}O{sub 5} phases to a level more suitable for thermoelectric applications. Electrical resistivity measurements performed on pure, bulk samples indicated all phases to be narrow band gap semiconductors or semimetals, supporting the charge balanced electron count of the Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} composition. Unfortunately, all samples are too electrically resistive for any potential usage as thermoelectrics. Electronic band structure calculations performed on idealized RE{sub 9}Pn{sub 5}O{sub 5} structures revealed the presence of a pseudogap at the Fermi level, which is consistent with the observed electrical resistivity and Seebeck coefficient behavior. - Graphical abstract: Ca substitution in RE{sub 9}Pn{sub 5}O{sub 5} leads to charge-balanced Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases with semiconducting or semimetallic properties. - Highlights: • The RE{sub 9}Pn{sub 5}O{sub 5} structure may be stabilized with calcium substitution in the form of Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5}. • The Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases maintain the parent P 4/n structure, albeit with Ca/RE mixing. • The Ca{sub 2}RE{sub 7}Sb{sub 5}O{sub 5} phases behave as semiconductors while Ca{sub 2}RE{sub 7}Bi{sub 5}O{sub 5} are semimetals with electron-electron correlations. • Electronic structure calculations yield a semimetal-like density of states for both Ca{sub 2}RE{sub 7}Sb{sub 5}O{sub 5} and Ca{sub 2}RE{sub 7}Bi{sub 5}O{sub 5}.

Thickness dependent quantum oscillations of transport properties in topological insulator Bi{sub 2}Te{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Rogacheva, E. I.; Budnik, A. V.; Sipatov, A. Yu.; Nashchekina, O. N. [National Technical University “Kharkov Polytechnic Institute,” 21 Frunze St., Kharkov 61002 (Ukraine); Dresselhaus, M. S. [Department of Electrical Engineering and Computer Science and Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)

2015-02-02

The dependences of the electrical conductivity, the Hall coefficient, and the Seebeck coefficient on the layer thickness d (d = 18−600 nm) of p-type topological insulator Bi{sub 2}Te{sub 3} thin films grown by thermal evaporation in vacuum on glass substrates were obtained at room temperature. In the thickness range of d = 18–100 nm, sustained oscillations with a substantial amplitude were revealed. The observed oscillations are well approximated by a harmonic function with a period Δd = (9.5 ± 0.5) nm. At d > 100 nm, the transport coefficients practically do not change as d is increased. The oscillations of the kinetic properties are attributed to the quantum size effects due to the hole confinement in the Bi{sub 2}Te{sub 3} quantum wells. The results of the theoretical calculations of Δd within the framework of a model of an infinitely deep potential well are in good agreement with the experimental results. It is suggested that the substantial amplitude of the oscillations and their sustained character as a function of d are connected with the topologically protected gapless surface states of Bi{sub 2}Te{sub 3} and are inherent to topological insulators.

Evolution of compact stars and dark dynamical variables

Energy Technology Data Exchange (ETDEWEB)

Bhatti, M.Z.; Yousaf, Z. [University of the Punjab, Department of Mathematics, Lahore (Pakistan); Ilyas, M. [University of the Punjab, Centre for High Energy Physics, Lahore (Pakistan)

2017-10-15

This work aims to explore the dark dynamical effects of the f(R, T) modified gravity theory on the dynamics of a compact celestial star. We have taken the interior geometry of a spherical star which is filled with an imperfect fluid distribution. The modified field equations are explored by taking a particular form of the f(R, T) model, i.e. f(R, T) = f{sub 1}(R) + f{sub 2}(R)f{sub 3}(T). These equations are utilized to formulate the well-known structure scalars under the dark dynamical effects of this higher-order gravity theory. Also, with the help of these scalar variables, the evolution equations for expansion and shear are formulated. The whole analysis is made under the condition of a constant R and T. We found a crucial significance of dark source terms and dynamical variables on the evolution and density inhomogeneity of compact objects. (orig.)

High temperature aircraft research furnace facilities

Science.gov (United States)

Smith, James E., Jr.; Cashon, John L.

1992-01-01

Focus is on the design, fabrication, and development of the High Temperature Aircraft Research Furnace Facilities (HTARFF). The HTARFF was developed to process electrically conductive materials with high melting points in a low gravity environment. The basic principle of operation is to accurately translate a high temperature arc-plasma gas front as it orbits around a cylindrical sample, thereby making it possible to precisely traverse the entire surface of a sample. The furnace utilizes the gas-tungsten-arc-welding (GTAW) process, also commonly referred to as Tungsten-Inert-Gas (TIG). The HTARFF was developed to further research efforts in the areas of directional solidification, float-zone processing, welding in a low-gravity environment, and segregation effects in metals. The furnace is intended for use aboard the NASA-JSC Reduced Gravity Program KC-135A Aircraft.

Sb{sub 2}Te{sub 3} nanobelts and nanosheets: Hydrothermal synthesis, morphology evolution and thermoelectric properties

Energy Technology Data Exchange (ETDEWEB)

Dong, Guo-Hui [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhu, Ying-Jie, E-mail: y.j.zhu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Cheng, Guo-Feng; Ruan, Yin-Jie [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2013-02-15

Graphical abstract: Sb{sub 2}Te{sub 3} nanobelts and nanosheets were synthesized by a hydrothermal method, and the morphology evolution from Sb{sub 2}Te{sub 3} nanobelts to nanosheets with the prolonging hydrothermal time was observed. Highlights: Black-Right-Pointing-Pointer Hydrothermal synthesis of Sb{sub 2}Te{sub 3} nanobelts and nanosheets is demonstrated. Black-Right-Pointing-Pointer The morphology of Sb{sub 2}Te{sub 3} can be adjusted by varying hydrothermal time. Black-Right-Pointing-Pointer The morphology evolution of Sb{sub 2}Te{sub 3} from nanobelts to nanosheets is observed. Black-Right-Pointing-Pointer High Seebeck coefficients (S) of Sb{sub 2}Te{sub 3} nanobelts and nanosheets are attained. - Abstract: Sb{sub 2}Te{sub 3} nanobelts and nanosheets were synthesized by a hydrothermal method using SbCl{sub 3} and TeO{sub 2} as the antimony and tellurium source, hydrazine hydrate as a reducing reagent, polyvinyl alcohol as a surfactant and water as the solvent. The effects of experimental parameters on the product were investigated. The experiments indicated that the elemental Te formed during the reaction, acting as a reactive and self-sacrificial template for the formation of Sb{sub 2}Te{sub 3} nanobelts. The morphology evolution from Sb{sub 2}Te{sub 3} nanobelts to nanosheets with the prolonging hydrothermal time was observed. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), selected area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The thermoelectric properties of the tablet samples of Sb{sub 2}Te{sub 3} nanostructured powders with different morphologies prepared by a room-temperature pressurized method were investigated.

Determination of uranium in coated fuel particle compact by potassium fluoride fusion-gravimetric method

International Nuclear Information System (INIS)

Ito, Mitsuo; Iso, Shuichi; Hoshino, Akira; Suzuki, Shuichi.

1992-03-01

Potassium fluoride-gravimetric method has been developed for the determination of uranium in TRISO type-coated fuel particle compact. Graphite matrix in the fuel compact is burned off by heating it in a platinum crucible at 850degC. The coated fuel particles thus obtained are decomposed by fusion with potassium fluoride at 900degC. The melt was dissolved with sulfuric acid. Uranium is precipitated as ammonium diuranate, by passing ammonia gas through the solution. The resulting precipitate is heated in a muffle furnace at 850degC, to convert uranium into triuranium octoxide. Uranium in the triuranium octoxide was determined gravimetrically. Ten grams of caoted fuel particles were completely decomposed by fusion with 50 g of potassium fluoride at 900degC for 3 hrs. Analytical result for uranium in the fuel compact by the proposed method was 21.04 ± 0.05 g (n = 3), and was in good agreement with that obtained by non-destructive γ-ray measurement method : 21.01 ± 0.07 g (n = 3). (author)

Assessment of selected furnace technologies for RWMC waste

International Nuclear Information System (INIS)

Batdorf, J.; Gillins, R.; Anderson, G.L.

1992-03-01

This report provides a description and initial evaluation of five selected thermal treatment (furnace) technologies, in support of earlier thermal technologies scoping work for application to the Idaho National Engineering Laboratory Radioactive Waste Management Complex (RWMC) buried wastes. The cyclone furnace, molten salt processor, microwave melter, ausmelt (fuel fired lance) furnace, and molten metal processor technologies are evaluated. A system description and brief development history are provided. The state of development of each technology is assessed, relative to treatment of RWMC buried waste

Internal heat exchange tubes for industrial furnaces

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1992-05-26

This patent describes a method for cooling the work within an industrial furnace. It comprises providing a longitudinally extending outer tube which extends into the furnace having a closed axial end and an open axial end; providing a preformed inner tube open at both ends within the outer tube; injecting a coolant into the inner tube so that the coolant flows from one axial end of the tube out the opposite end adjacent the closed end of the outer tube, and from the closed end of the outer tube to the open end thereof; circulating a gas within the furnace against the outer tube to effect heat transfer therewith.

Uranium casting furnace automatic temperature control development

International Nuclear Information System (INIS)

Lind, R.F.

1992-01-01

Development of an automatic molten uranium temperature control system for use on batch-type induction casting furnaces is described. Implementation of a two-color optical pyrometer, development of an optical scanner for the pyrometer, determination of furnace thermal dynamics, and design of control systems are addressed. The optical scanning system is shown to greatly improve pyrometer measurement repeatability, particularly where heavy floating slag accumulations cause surface temperature gradients. Thermal dynamics of the furnaces were determined by applying least-squares system identification techniques to actual production data. A unity feedback control system utilizing a proportional-integral-derivative compensator is designed by using frequency-domain techniques. 14 refs

LASL Compact Torus Program

International Nuclear Information System (INIS)

Linford, R.K.; Armstrong, W.T.; Bartsch, R.R.

1981-01-01

The Compact Torus (CT) concept includes any axisymmetric toroidal plasma configuration, which does not require the linking of any material through the hole in the torus. Thus, the magnet coils, vacuum vessel, etc., have a simple cylindrical or spherical geometry instead of the toroidal geometry required for Tokamaks and RFP's. This simplified geometry results in substantial engineering advantages in CT reactor embodiments while retaining the good confinement properties afforded by an axisymmetric toroidal plasma-field geometry. CT's can be classified into three major types by using the ion gyro radius rho/sub i/ and the magnitude of the maximum toroidal field B/sub tm/

A furnace for firing carbon products

Energy Technology Data Exchange (ETDEWEB)

Sudavskii, A M

1979-12-05

A furnace for firing carbon products is patented that consists of several chambers with a perforated hearth, which are interconnected by a lower and an upper reservoir with a locking fixture, and a flue. In order to intensify the firing process by increasing the specific hearth productivity, the flue is connected to the upper reservoir. A block diagram of the patented furnace is given, together with a description of its operation.

Electronic structure and thermoelectricity of filled skutterudite CeRu{sub 4}Sb{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Shankar, A., E-mail: amitshan2009@gmail.com [Department of Physics, University of North Bengal, Darjeeling, 734013 (India); Rai, D.P. [Department of Physics, Pachhunga University College, Aizawl, 796001 (India); Sandeep [Condensed Matter Theory Research Group, Department of Physics, Mizoram University, Aizawl, 796004 (India); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 (Algeria); Thapa, R.K. [Condensed Matter Theory Research Group, Department of Physics, Mizoram University, Aizawl, 796004 (India); Mandal, P.K. [Department of Physics, University of North Bengal, Darjeeling, 734013 (India)

2016-07-05

First-principles calculations of the energy band structure and density of states of filled skutterudite CeRu{sub 4}Sb{sub 12} have been performed to understand the origin of thermoelectricity. The calculations are carried out using the full potential linear augmented plane wave (FP-LAPW) method within a framework of LDA approach. CeRu{sub 4}Sb{sub 12} is a metal with bands crossing Fermi energy level more than twice with indirect energy band gap of ∼0.09 eV above the Fermi energy level. The study of the elastic properties suggests the ductile nature of the material with covalent contribution in the atomic bonding. Our calculations performed for the density of electronic states near the Fermi energy level show that the large thermo-power at room temperature originates from the hybridized Ru-d and Sb-p orbitals. The study of the thermal transport properties suggests the high value of Seebeck coefficient with figure of merit (ZT) = 0.12, which is consistent to the values obtained for the analogous compounds. - Highlights: • CeRu{sub 4}Sb{sub 12} is ductile material with covalent contribution in bonding. • An indirect energy bandgap of 0.09 eV is present above the Fermi energy level. • The crossing of E{sub F} by the energy bands increases the number of DOS at E{sub F}. • Fermi level is situated within the valence region. • The thermal efficiency of the material is 0.12 at room temperature.

Elements of the electric arc furnace's environmental management

Science.gov (United States)

Ioana, Adrian; Semenescu, Augustin; Costoiu, Mihnea; Marcu, Dragoş

2017-12-01

The paper presents a theoretical and experimental analysis of the polluting generating mechanisms for steel making in the Electric Arc Furnaces (EAF). The scheme for the environment's polluting system through the EAF is designed and presented in this paper. The ecological experimenting consisted of determining by specialized measures of the dust percentage in the evacuated gases from the EAF and of thereof gas pollutants. From the point of view of reducing the impact on the environment, the main problem of the electric arc furnace (EAF) is the optimization of the powder collecting from the process gases, both from the furnace and from the work-area. The paper deals with the best dependence between the aggregate's constructive, functional and technological factors, which are necessary for the furnace's ecologization and for its energetically-technologically performances increasing.

Influence of particle sizes on the electronic behavior of Zn{sub x}Co{sub 1−x}Fe{sub 2}O{sub 4} spinels (x = 0.2, 0.3)

Energy Technology Data Exchange (ETDEWEB)

Viñas, R. [Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Álvarez-Serrano, I., E-mail: ias@quim.ucm.es [Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); López, M.L.; Pico, C.; Veiga, M.L. [Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Mompeán, F.; García-Hernández, M. [Instituto de Ciencia de Materiales, CSIC, Sor Juana Inés de la Cruz, 3, 28049 Madrid (Spain)

2014-07-15

Graphical abstract: Relaxor ferroelectric behavior and superparamagnetism in nanoparticles of Zn{sub x}Co{sub 1−x}Fe{sub 2}O{sub 4} obtained in supercritical water. - Highlights: • Title ferrites were prepared by hydrothermal techniques (sub and supercritical). • In supercritical (SCW) conditions highly monodispersive samples were obtained. • All samples are semiconductors; n-type or p-type response depends on the composition. • Superparamagnetic and relaxor ferroelectric response coexist in SCW samples. - Abstract: The effect of composition and particle size on the electrical and magnetic behavior of Zn{sub x}Co{sub 1−x}Fe{sub 2}O{sub 4} spinels (x = 0.2 and 0.3) has been studied. Powdered samples of these ferrites have been synthetized by the liquid mix technique and hydrothermal method (in sub and supercritical conditions), leading to average particle sizes of ca. 50 and 10 nm, respectively. They have been characterized by means of X-ray diffraction, Thermogravimetric analysis, Energy-Dispersive X-ray Spectroscopy and impedance and magnetic measurements. Permittivity values up to ca. 500 were registered at 375 K, which remained almost constant at moderate frequencies, between 10{sup 3} and 10{sup 6} Hz. Stabilization of polarization phenomena is very sensitive to grain size and composition. Dielectric behavior evolves to a relaxor ferroelectric response when grain size becomes nanometric and, particularly, when the sample shows high monodispersion. The conduction mechanism and type of majority charge carriers have been established from Seebeck measurements. The x = 0.3 sample, prepared in supercritical water for the first time, exhibits homogeneous particle size distribution, superparamagnetic behavior and Curie temperature lower than those corresponding to similar microsized samples. The electronic response of the ferrites obtained in supercritical conditions is interpreted considering the possible short scale polarization of nanodomains.

Methods for monitoring heat flow intensity in the blast furnace wall

Directory of Open Access Journals (Sweden)

L'. Dorčák

2010-04-01

Full Text Available In this paper we present the main features of an online system for real-time monitoring of the bottom part of the blast furnace. Firstly, monitoring concerns the furnace walls and furnace bottom temperatures measurement and their visualization. Secondly, monitored are the heat flows of the furnace walls and furnace bottom. In the case of two measured temperatures, the heat flow is calculated using multi-layer implicit difference scheme and in the case of only one measured temperature, the heat flow is calculated using a method based on application of fractional-order derivatives. Thirdly, monitored is the theoretical temperature of the blast furnace combustion process in the area of tuyeres.

Field-reversed experiments (FRX) on compact toroids

Energy Technology Data Exchange (ETDEWEB)

Armstrong, W.T.; Linford, R.K.; Lipson, J.; Platts, D.A.; Sherwood, E.G.

1981-11-01

Equilibrium, stability, and confinement properties of compact toroids produced in field-reversed theta-pinch experiments (FRX) are reported. Two experimental facilities, FRX-A and FRX-B, have been used to study highly elongated compact toroid plasmas confined in a purely poloidal field geometry. Spatial scans and fill pressure scaling of the equilibrium plasma parameters are presented. Plasma conditions range from T/sub e/approx.150 eV, T/sub i/approx.800 eV, n/sub m/approx.1 x 10/sup 15/ cm/sup -3/ to T/sub e/approx.100 eV, T/sub i/approx.150 eV, n/sub m/approx.4 x 10/sup 15/ cm/sup -3/. Typical confined plasma dimensions are: major radius Rapprox.4 cm, minor radius aapprox.2 cm, and total length 35--50 cm. The plasma configuration remains in a stable equilibrium for up to 50 ..mu..sec followed by the destructive n = 2 rotational instability. The stable period prior to the onset of the rotational mode is up to one hundred times greater than characteristic Alfven transit times of the plasma. This stable period increases and the mode growth rate decreases with increased a/rho/sub i/ (where rho/sub i/ is the ion gyroradius). Agreement of experimental and theoretical mode frequencies for the instability is observed. Preferential particle loss has been proposed as a likely cause of rotation. The particle inventory at the onset of the instability is consistent with this hypothesis. The particle loss rate is also consistent with the predicted anomalous transport near the separatrix. Contributions to rotational instability from diffusion, end-shorting, equipartition, and compression are also discussed.

Field-reversed experiments (FRX) on compact toroids

International Nuclear Information System (INIS)

Armstrong, W.T.; Linford, R.K.; Lipson, J.; Platts, D.A.; Sherwood, E.G.

1981-01-01

Equilibrium, stability, and confinement properties of compact toroids produced in field-reversed theta-pinch experiments (FRX) are reported. Two experimental facilities, FRX-A and FRX-B, have been used to study highly elongated compact toroid plasmas confined in a purely poloidal field geometry. Spatial scans and fill pressure scaling of the equilibrium plasma parameters are presented. Plasma conditions range from T/sub e/approx.150 eV, T/sub i/approx.800 eV, n/sub m/approx.1 x 10 15 cm -3 to T/sub e/approx.100 eV, T/sub i/approx.150 eV, n/sub m/approx.4 x 10 15 cm -3 . Typical confined plasma dimensions are: major radius Rapprox.4 cm, minor radius aapprox.2 cm, and total length 35--50 cm. The plasma configuration remains in a stable equilibrium for up to 50 μsec followed by the destructive n = 2 rotational instability. The stable period prior to the onset of the rotational mode is up to one hundred times greater than characteristic Alfven transit times of the plasma. This stable period increases and the mode growth rate decreases with increased a/rho/sub i/ (where rho/sub i/ is the ion gyroradius). Agreement of experimental and theoretical mode frequencies for the instability is observed. Preferential particle loss has been proposed as a likely cause of rotation. The particle inventory at the onset of the instability is consistent with this hypothesis. The particle loss rate is also consistent with the predicted anomalous transport near the separatrix. Contributions to rotational instability from diffusion, end-shorting, equipartition, and compression are also discussed

Thermal Analysis of an Industrial Furnace

Directory of Open Access Journals (Sweden)

Mirko Filipponi

2016-10-01

Full Text Available Industries, which are mainly responsible for high energy consumption, need to invest in research projects in order to develop new managing systems for rational energy use, and to tackle the devastating effects of climate change caused by human behavior. The study described in this paper concerns the forging industry, where the production processes generally start with the heating of steel in furnaces, and continue with other processes, such as heat treatments and different forms of machining. One of the most critical operations, in terms of energy loss, is the opening of the furnace doors for insertion and extraction operations. During this time, the temperature of the furnaces decreases by hundreds of degrees in a few minutes. Because the dispersed heat needs to be supplied again through the combustion of fuel, increasing the consumption of energy and the pollutant emissions, the evaluation of the amount of lost energy is crucial for the development of systems which can contain this loss. To perform this study, CFD simulation software was used. Results show that when the door opens, because of temperature and pressure differences between the furnace and the ambient air, turbulence is created. Results also show that the amount of energy lost for an opening of 10 min for radiation, convection and conduction is equal to 5606 MJ where convection is the main contributor, with 5020 MJ. The model created, after being validated, has been applied to perform other simulations, in order to improve the energy performance of the furnace. Results show that reducing the opening time of the door saves energy and limits pollutant emissions.

Fluxless furnace brazing and its theoretical fundamentals

International Nuclear Information System (INIS)

Lison, R.

1979-01-01

In this paper the theoretical fundamental of fluxless furnace brazing are described. The necessary conditions for a wetting in the vacuum, under a inert-gas and with a reducing gas are discussed. Also other methods to reduce the oxygen partial pressure are described. Some applications of fluxless furnace brazing are outlined. (orig.) [de

Characterization of gas sensors for measurement of unburned gases in small district heating furnaces; Karaktaerisering av gassensorer foer maetning av ofoerbraenda aemnen i naervaermecentraler

Energy Technology Data Exchange (ETDEWEB)

Eskilsson, David; Roennbaeck, Marie [Swedish National Testing and Research Inst., Boraas (Sweden)

2004-11-01

Small district heating boilers are often equipped with a simple O{sub 2}-gauge (lambda sensor) that controls the air supply. There is a great need in small furnaces of continuous measurements of several gas components such as CO, THC and NO{sub x} by simple and cheap technique. Recently, new types of cheap gas sensors have been developed which can be suitable. These gas sensors measure the amount of unburned species (sum of carbon monoxide, hydrocarbons and hydrogen). The objective with this project has been to characterise several gas sensors for unburnt in order to evaluate if they are suitable for combustion control and surveillance of small district heating furnaces. In this work three different gas sensors have been characterised. The sensors were characterised in the laboratory where they were exposed for mixtures of pure gases. The sensors were mounted inside the flue gas channel from a small district heating furnace during 3 months in order to estimate the sensors robustness and the character of the signal in flue gas. The tests with pure gases show that all sensors also reacts for other components besides CO and THC. It is mainly the oxygen concentrations that affect the sensors characteristics but also an altered humidity is important. Measurements in the small district heating furnace showed that none of the sensors was able to measure correctly when mounted directly in the flue gas channel (in situ). The in situ sensors are covered with fly ash and the fly ash also slowly destroys the sensors. Sensors mounted after a filter (exposed for a particle free flue gas) work satisfactory. All of the tested sensors, mounted after a filter, follow the changes in CO concentration well. Some of the sensors are capable of detecting CO as low as 15 ppm. But the accuracy of how well the sensors are able to detect CO varies from sensor to sensor. The measurements also show that even if the sensor is able to follow the changes in CO concentration, the ground signal of

Materials and proportion's design of self-compacting mortar used for low diffusion layer in sub-surface radioactive waste disposal facility in Japan

International Nuclear Information System (INIS)

Niwase, Kazuhito; Sugihashi, Naoyuki; Tsuji, Yukikazu

2010-01-01

This paper describes the design procedure for the material selection and mix proportion of the self-compacting mortar used for low diffusion layer cementitious material in the sub-surface radioactive waste disposal facility in Japan. The low diffusion layer is required for reducing transportation by controlling diffusion of a radionuclide. Therefore the low diffusion, cracks control, and low leaching are the important matters in the mix design. The process to select mortar mix design of the low diffusion layer is explained in detail. Of 33 kinds mix proportions used in laboratory comparative testing, the combinations of low heat portland cement, fly ash, lime powder and expansive addition was provisionally set to the mix proportion of the self-compacting mortar used for low diffusion layer. (author)

Highly efficient CuIn{sub 1-x}Ga{sub x}Se{sub 2-y}S{sub y}/CdS thin-film solar cells by using diethylselenide as selenium precursor

Energy Technology Data Exchange (ETDEWEB)

Kadam, Ankur A.; Dhere, Neelkanth G. [Florida Solar Energy Center, University of Central Florida, Cocoa, FL 32922-5703 (United States)

2010-05-15

Conventional furnace selenization process was optimized to achieve effective selenization using diethylselenide (C{sub 2}H{sub 5}){sub 2}Se (DESe). An optimized quantity of Na was added to improve V{sub oc}, FF and morphology. Sputter-deposited CuGa and In metallic precursors were homogenized in an inert atmosphere prior to the introduction of DESe followed by rapidly heating to the maximum process temperature to avoid formation of detrimental binary phases. Selenization was carried out in the temperature range 475-515 C followed by sulfurization in dilute H{sub 2}S. Solar cells were completed by depositing CdS heterojunction partner layer, i:ZnO/ZnO:Al window-bilayer and metallic contact fingers. PV conversion efficiency of 13.7% with a V{sub oc} of 540 mV, J{sub sc} of 38.3 mA/cm{sup 2} and FF of 66.3% were obtained on 0.442 cm{sup 2} cell areas. The process can be easily scaled-up for economic large-scale manufacture. (author)

Fuel sparing: Control of industrial furnaces using process gas as supplemental fuel

International Nuclear Information System (INIS)

Boisvert, Patrick G.; Runstedtler, Allan

2014-01-01

Combustible gases from industrial processes can be used to spare purchased fuels such as natural gas and avoid wasteful flaring of the process gases. One of the challenges of incorporating these gases into other furnaces is their intermittent availability. In order to incorporate the gases into a continuously operating furnace, the furnace control system must be carefully designed so that the payload is not affected by the changing fuel. This paper presents a transient computational fluid dynamics (CFD) model of an industrial furnace that supplements natural gas with carbon monoxide during furnace operation. A realistic control system of the furnace is simulated as part of the CFD calculation. The time dependent changes in fuels and air injection on the furnace operation is observed. It is found that there is a trade-off between over-controlling the furnace, which results in too sensitive a response to normal flow oscillations, and under-controlling, which results in a lagged response to the fuel change. - Highlights: •Intermittently available process gases used in a continuously operating furnace. •Study shows a trade-off between over-controlling and under-controlling the furnace. •Over-controlling: response too sensitive to normal flow oscillations. •Under-controlling: lagged response to changing fuel composition. •Normal flow oscillations in furnace would not be apparent in steady-state model

Surface desorption and bulk diffusion models of tritium release from Li{sub 2}TiO{sub 3} and Li{sub 2}ZrO{sub 3} pebbles

Energy Technology Data Exchange (ETDEWEB)

Avila, R.E., E-mail: ravila@cchen.c [Departamento de Materiales Nucleares, Comision Chilena de Energia Nuclear, Cas. 188-D, Santiago (Chile); Pena, L.A.; Jimenez, J.C. [Departamento de Produccion y Servicios, Comision Chilena de Energia Nuclear, Cas. 188-D, Santiago (Chile)

2010-10-30

The release of tritium from Li{sub 2}TiO{sub 3} and Li{sub 2}ZrO{sub 3} pebbles, in batch experiments, is studied by means of temperature programmed desorption. Data reduction focuses on the analysis of the non-oxidized and oxidized tritium components in terms of release limited by diffusion from the bulk of ceramic grains, or by first or second order surface desorption. By analytical and numerical methods the in-furnace tritium release is deconvoluted from the ionization chamber transfer functions, for which a semi-empirical form is established. The release from Li{sub 2}TiO{sub 3} follows second order desorption kinetics, requiring a temperature for a residence time of 1 day (T{sub 1dRes}) of 620 K, and 603 K, of the non-oxidized, and the oxidized components, respectively. The release from Li{sub 2}ZrO{sub 3} appears as limited by either diffusion from the bulk of the ceramic grains, or by first order surface desorption, the first possibility being the more probable. The respective values of T{sub 1dRes} for the non-oxidized component are 661 K, according to the first order surface desorption model, and 735 K within the bulk diffusion limited model.

Synthesis of nanocrystalline nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films by chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Pawar, D.K. [Department of Chemistry, Shivaji University, Kolhapur 416 004 (M.S.) (India); Pawar, S.M. [Department of Materials Science and Engineering, Chonnam National University, 500 757 (Korea, Republic of); Patil, P.S. [Department of Physics, Shivaji University, Kolhapur 416 004 (M.S.) (India); Kolekar, S.S., E-mail: kolekarss2003@yahoo.co.in [Department of Chemistry, Shivaji University, Kolhapur 416 004 (M.S.) (India)

2011-02-24

Graphical abstract: Display Omitted Research highlights: > We have successfully synthesized nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films on stainless steel substrates using a low temperature chemical bath deposition method. > The surface morphological study showed the compact flakes like morphology. > The as-deposited thin films are hydrophilic (10{sup o} < {theta} < 90{sup o}) whereas the annealed thin films are super hydrophilic ({theta} < 10{sup o}) in nature. > Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films could be used in supercapacitor. - Abstract: The nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films have been successfully deposited on stainless steel substrates using a chemical bath deposition method from alkaline bath. The films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), static water contact angle and cyclic voltammetry measurements. The X-ray diffraction pattern shows that deposited Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films were oriented along (3 1 1) plane. The FTIR spectra showed strong absorption peaks around 600 cm{sup -1} which are typical for cubic spinel crystal structure. SEM study revealed compact flakes like morphology having thickness {approx}1.8 {mu}m after air annealing. The annealed films were super hydrophilic in nature having a static water contact angle ({theta}) of 5{sup o}.The electrochemical supercapacitor study of Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films has been carried out in 6 M KOH electrolyte. The values of interfacial and specific capacitances obtained were 0.0285 F cm{sup -2} and 19 F g{sup -1}, respectively.

Feasibility study of utilizing solar furnace technology in steel making industry

Energy Technology Data Exchange (ETDEWEB)

Abbaspoursani, K. [The Faculty of Mechanical Engineering, Takestan Islamic Azad University (Iran, Islamic Republic of)], Email: a.abbaspour@tiau.ac.ir; Tofigh, A.A.; Nahang Toudeshki, S.; Hadadian, A. [Department of Energy, Materials and Energy Research Center (Iran, Islamic Republic of)], Email: Ali.A.Tofigh@gmail.com, email: toudeshki@hotmail.com, email: Arash.Hadadian@gmail.com; Farahmandpour, B. [Iranian Fuel Conservation company (Iran, Islamic Republic of)], Email: farahmandpour@gmail.com

2011-07-01

In Iran, the casting industry consumes 33.6% of electricity production, and most of this electricity is used in the melting process. Currently, scrap preheating is done using electric arc furnaces and the aim of this study is to assess the feasibility of replacing electric arc furnaces with solar furnaces. The performance of solar furnaces in the Iran Alloy Steel Company under Yazd climate conditions was studied. It was found that the solar irradiation time and solar insulation are sufficient to operate a solar furnace with the capacity to preheat 250 thousand tons per year of scrap to 500 degrees celsius. Results showed that such a furnace would decrease energy consumption by 40 GWh per year and that it would take 5 years to return the investment. This study demonstrated that operating a solar furnace in the Iran Alloy Steel Company under Yazd climate conditions is feasible and would result in economic and environmental benefits.

10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial warm air furnaces. 431... CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces § 431.72 Definitions concerning commercial warm air furnaces. The following definitions apply for purposes of this subpart D, and of subparts...

Local structure and thermoelectric properties of Mg{sub 2}Si{sub 0.977−x}Ge{sub x}Bi{sub 0.023} (0.1 ⩽ x ⩽ 0.4)

Energy Technology Data Exchange (ETDEWEB)

Farahi, Nader [Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Prabhudev, Sagar; Botton, Gianluigi A. [Materials Science and Engineering Department, McMaster University, Hamilton, ON L8S 4L8 (Canada); Zhao, Jianbao; Tse, John S. [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK S7N 5E2 (Canada); Liu, Zhenxian [Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015 (United States); Salvador, James R. [General Motors Research & Development Center, Warren, MI 48090 (United States); Kleinke, Holger, E-mail: kleinke@uwaterloo.ca [Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)

2015-09-25

Highlights: • Incorporating Ge into Bi-doped Mg{sub 2}Si decreases the thermal conductivity and enhances the thermoelectric performance. • Ge-rich domains, identified via TEM, contribute to these changes. • Interstitial sites are in part filled with Mg atoms, as revealed via TEM. • Doping with Bi is advantageous over doping with Sb, resulting in an increase of 48% of the thermoelectric figure of merit. • The highest figure-of-merit of these materials is zT{sub max} = 0.7 at 773 K, realized for Mg{sub 2}Si{sub 0.677}Ge{sub 0.3}Bi{sub 0.023}. - Abstract: We investigated the effect of germanium substitution for silicon in bismuth doped Mg{sub 2}Si. This alloying reduces the thermal conductivity from above 7 W m{sup −1} K{sup −1} to 2.7 W m{sup −1} K{sup −1} at around 300 K in part due to the added mass contrast. High resolution transmission electron microscopy (HRTEM) revealed the presence of Ge-rich domains within the Mg{sub 2}(Si,Ge,Bi) particles, contributing to decreasing thermal conductivity with increasing Ge content up to 0.3 Ge per formula unit. The electrical conductivity also decreases with Ge alloying because of the increasing amount of scattering centers, while the Seebeck coefficient increased only very slightly. In total, the positive effect of Ge substitution on the thermoelectric properties of Bi doped Mg{sub 2}Si resulted in a figure of merit of 0.7 at 773 K for Mg{sub 2}Si{sub 0.677}Ge{sub 0.3}Bi{sub 0.023} sample. The optimum amount of Bi seems to be 0.023 per formula unit (0.77 at%), since lower Bi content resulted in electrical conductivity that is too low, and higher Bi content generated the Mg{sub 3}Bi{sub 2} intermetallic phase.

Investigation of spectral interferences in the determination of lead in fertilizers and limestone samples using high-resolution continuum source graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; François, Luciane L.; Jesus, Alexandre de [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Andrade, Jailson B. de [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

2014-11-01

In the present work, spectral interferences on the determination of lead in fertilizer and limestone samples were investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry at the main analytical lines: 217.001 and 283.306 nm. For these investigations, samples were introduced into the furnace as slurry together with a mixture of Pd and Mg as chemical modifier. Spectral interferences were observed for some samples at both analytical lines. In order to verify whether a wet digestion procedure would avoid these interferences, a reference method for wet digestion of fertilizers was employed as an alternative sample preparation procedure. However, the same interferences were also observed in the digested samples. In order to identify and eliminate the fine-structured background using a least-squares background correction, reference spectra were generated using the combination of different species. The use of the latter technique allowed the elimination of spectral interferences for most of the investigated samples, making possible the determination of lead in fertilizer and limestone samples free of interferences. The best results were found using a reference spectrum of NH{sub 4}H{sub 2}PO{sub 4} at 217.001 nm, and a mixture of H{sub 2}SO{sub 4} + Ca and HNO{sub 3} + Ca at the 283.306 nm line. The accuracy of the method was evaluated using a certified reference material “Trace Elements in Multi-Nutrient Fertilizer”. Similar results were obtained using line source graphite furnace atomic absorption spectrometry with Zeeman-effect background correction, indicating that the latter technique was also capable to correct the spectral interferences, at least in part. - Highlights: • Spectral interferences on the determination of lead in fertilizers and limestone. • The analytical lines at 217.001 nm and 283.306 nm using HR-CS GF AAS. • Various combinations of compounds were used to create reference spectra. • LSBC

Synthesis, characterization and comparison of Li{sub 1,05}M{sub 0,02}Mn{sub 1,98}O{sub 4} (M = Al{sup 3+} or + Ga{sup 3+}) obtained by calcination in muffle and microwave; Sintese, caracterizacao e comparacao dos Li{sub 1,05}Mn{sub 1,98}M{sub 0,02}O{sub 4} (M= Al{sup 3+} ou GA{sup 3+}) obtidos por calcinacao em mufla e microondas

Energy Technology Data Exchange (ETDEWEB)

Santana, L.K.; Canobre, S.C.; Amaral, F.A., E-mail: fabioamaral@yahoo.com.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Quimica. Laboratorio de Armazenamento de Energia e Tratamento de Efluentes

2014-07-01

Due to the economic and environmental importance of using LiMn{sub 2}O{sub 4} as cathode batteries, the goal of this work was to synthesize LiMn{sub 2}O{sub 4} doped and undoped, comparing methods of calcination kiln and microwave. The precursors were obtained by Pechini method. The resulting samples were structurally characterized by XRD, morphology by SEM and area by B.E.T. XRD results were compared to card JCPDS 35-0782 regarding the pure LiMn{sub 2}O{sub 4}. The DRX results indicate that the calcination furnace was more efficient for obtaining doped oxides. However, the use of microwave was effective for rapid attainment of non-doped spinel close to those found for the pure spinel structural features. The surface area values confirm the existence of clusters and particles with nanometric features. Oxides synthesized in both procedures showed small, organized and highly crystalline particles, demonstrating the efficiency of the methodology and Pechini methods of calcination compared. (author)

Investigations on oxy-fuel combustion in glass melting furnaces; Untersuchungen zur Oxy-Fuel-Feuerung in Glasschmelzwannen

Energy Technology Data Exchange (ETDEWEB)

Leicher, Joerg; Giese, Anne [Gaswaerme-Institut e.V., Essen (Germany)

2011-12-15

Glass melting requires process temperatures of more than 1600 C which are usually achieved using intensive air preheating and near-stoichiometric combustion. This often leads to high nitrous oxide emissions (NO{sub x}). Oxy-fuel technology offers an interesting alternative since high combustion temperatures can be achieved using pure oxygen as oxidizer while obtaining low NO{sub x} emissions. In the course of the AiF research project ''O2-Glaswanne'' (IGF-Nr.: 15987 N), Gaswaerme- Institut e.V. Essen investigates this combustion process by experimental and numerical means in order to determine potential optimization approaches for glass melting furnaces.

Thermal stability of Ti{sub 3}SiC{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Emmerlich, Jens [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden)]. E-mail: jenem@ifm.liu.se; Music, Denis [Materials Chemistry, RWTH Aachen University, Kopernikusstrasse 16, D-52074 Aachen (Germany); Eklund, Per [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden); Wilhelmsson, Ola [Uppsala University, Department of Materials Chemistry, The Angstroem Laboratory, P.O. Box 538, SE-751 21 Uppsala (Sweden); Jansson, Ulf [Uppsala University, Department of Materials Chemistry, The Angstroem Laboratory, P.O. Box 538, SE-751 21 Uppsala (Sweden); Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, Kopernikusstrasse 16, D-52074 Aachen (Germany); Hoegberg, Hans [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden); Hultman, Lars [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden)

2007-02-15

The thermal stability of Ti{sub 3}SiC{sub 2}(0 0 0 1) thin films is studied by in situ X-ray diffraction analysis during vacuum furnace annealing in combination with X-ray photoelectron spectroscopy, transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray analysis. The films are found to be stable during annealing at temperatures up to {approx}1000 deg. C for 25 h. Annealing at 1100-1200 deg. C results in the rapid decomposition of Ti{sub 3}SiC{sub 2} by Si out-diffusion along the basal planes via domain boundaries to the free surface with subsequent evaporation. As a consequence, the material shrinks by the relaxation of the Ti{sub 3}C{sub 2} slabs and, it is proposed, by an in-diffusion of O into the empty Si-mirror planes. The phase transformation process is followed by the detwinning of the as-relaxed Ti{sub 3}C{sub 2} slabs into (1 1 1)-oriented TiC{sub 0.67} layers, which begin recrystallizing at 1300 deg. C. Ab initio calculations are provided supporting the presented decomposition mechanisms.

TECHNOLOGICAL PECULIARITIES O F MELTING AND OUT-OF-FURNACE PROCESSING OF BALANCED STEELS IN CONDITIONS OF ELECTRIC FURNACE STEELMAKING AND CONTINUOUS CASTING

Directory of Open Access Journals (Sweden)

S. V. Terletski

2007-01-01

Full Text Available The technological peculiarities of melting and out-of-furnace processing of balanced steels in conditions of electric furnace steelmaking and continuous cast of RUP “BMZ” are considered.

EFFECT OF DIFFERENT COMPACTION PRESSURE AND DIFFERENT SINTERING ROUTE ON K0.5NA0.5NBO₃ PHYSICAL AND DIELECTRIC PROPERTIES

Directory of Open Access Journals (Sweden)

Nor Fatin Khairah Bahanurddin

2016-07-01

Full Text Available Alkaline niobate known as K0.5Na0.5NbO3 (KNN, a lead-free piezoelectric ceramic was synthesized via a solid state reaction method. The samples were compacted at different pressures (100, 200, 300 and 400 MPa and sintered using two different techniques (conventional furnace and hot isostatic pressing (HIP. The effect of compaction pressure and sintering technique on physical and dielectric properties was studied. The optimum compaction pressure (300 MPa and sintering via HIP (at 1080 °C for 30 min increased the density and grain size ( range 30 - 300 nm and improved its dielectric properties. Therefore, the combination of suitable compaction pressure and sintering technique has produced larger grain size and higher density of KNN which resulted in outstanding dielectric properties. At room temperature, excellent values of ε r (5517.35 and tan δ (0.954, recorded at 1 MHz were measured for the KNN300HIP sample with highest density (4.4885 g/cm³.

Electronic-structure origin of the anisotropic thermopower of nanolaminated Ti3SiC2 determined by polarized x-ray spectroscopy and Seebeck measurements

DEFF Research Database (Denmark)

Magnuson, Martin; Mattesini, Maurizio; Van Nong, Ngo

2012-01-01

Nanolaminated materials exhibit characteristic magnetic, mechanical, and thermoelectric properties, with large contemporary scientific and technological interest. Here we report on the anisotropic Seebeck coefficient in nanolaminated Ti3SiC2 single-crystal thin films and trace the origin to aniso......Nanolaminated materials exhibit characteristic magnetic, mechanical, and thermoelectric properties, with large contemporary scientific and technological interest. Here we report on the anisotropic Seebeck coefficient in nanolaminated Ti3SiC2 single-crystal thin films and trace the origin...... value of 4–6 μV/K. Employing a combination of polarized angle-dependent x-ray spectroscopy and density functional theory we directly show electronic structure anisotropy in inherently nanolaminated Ti3SiC2 single-crystal thin films as a model system. The density of Ti 3d and C 2p states at the Fermi...... level in the basal ab plane is about 40% higher than along the c axis. The Seebeck coefficient is related to electron and hole-like bands close to the Fermi level, but in contrast to ground state density functional theory modeling, the electronic structure is also influenced by phonons that need...

Mathematical modelling of straw combustion in a 38 MWe power plant furnace and effect of operating conditions

Energy Technology Data Exchange (ETDEWEB)

Yao Bin Yang; Robert Newman; Vida Sharifi; Jim Swithenbank; John Ariss [Sheffield University, Sheffield (United Kingdom). Sheffield University Waste Incineration Centre (SUWIC), Department of Chemical and Process Engineering

2007-01-15

As one of the most easily accessible renewable energy resources, straw can be burned to provide electricity and heat to local communities. In this paper, mathematical modelling methods have been employed to simulate the operation of a 38 MWe straw-burning power plant to obtain detailed information on the flow and combustion characteristics in the furnace and to predict the effect on plant performance of variation in operating conditions. The predicted data are compared to measurements in terms of burning time, furnace temperature, flue gas emissions (including NOx), carbon content in the ash and overall combustion efficiency. It is concluded that straw burning on the grate is locally sub-stoichiometric and most of the NO is formed in the downstream combustion chamber and radiation shaft; auxiliary gas burners are responsible for the uneven distribution of temperature and gas flow at the furnace exit; and fuel moisture content is limited to below 25% to prevent excessive CO emission without compromising the plant performance. The current work greatly helps to understand the operating characteristics of large-scale straw-burning plants. 33 refs., 15 figs., 3 tabs.

Mechanical properties of bismuth telluride (Bi{sub 2}Te{sub 3}) processed by high pressure torsion (HPT); Propiedades mecanicas del telururo de bismuto (Bi{sub 2}Te{sub 3}) procesado mediante torsion bajo alta presion (HPT)

Energy Technology Data Exchange (ETDEWEB)

Santamaria, J. A.; Alkorta, J.; Gil Sevillano, J.

2013-06-01

Bismuth telluride, Bi{sub 2}Te{sub 3}, is the main thermoelectric material currently in use for commercial cooling devices or for energy harvesting near room temperature. Because of its highly anisotropic layered structure, Bi{sub 2}Te{sub 3} is very brittle, failing by cleavage along its basal plane. Refining its grain size is expected to increase its toughness with the advantage that, simultaneously, its thermoelectric figure of merit results increased. In this work, powders of the compound have been compacted by conventional methods as well as by severe plastic deformation under high pressure (3 GPa) using high pressure torsion (HPT, one turn at room temperature). Near-theoretical density has been achieved. The hardness and toughness of the compacts have been assessed by micro and nano-indentation. (Author) 11 refs.

Fundamental study of the pulverized coal char combustion in oxyfuel mode with drop tube furnace

Energy Technology Data Exchange (ETDEWEB)

Ito, Takamasa; Takafuji, Makoto; Suda, Toshiyuki; Fujimori, Toshiro [Heat and Fluid Dynamics Department, Yokohama (Japan)

2013-07-01

The combustion characteristics of coal char particles in either O{sub 2}/N{sub 2} or O{sub 2}/CO{sub 2} conditions were experimentally investigated. Especially, the char burnout, the char particle temperature and the shrinkage of the char particles were discussed. A Drop Tube Furnace (DTF: whose wall temperature was set at 873, 923 and 973 K) was used as the experimental apparatus. The experimental results revealed that, in equivalent oxygen concentration, the char burnout and the char particle temperature were higher in O{sub 2}/N{sub 2} conditions than those in O{sub 2}/CO{sub 2} conditions. The shrinkage of the char particle did not show the large difference in either O{sub 2}/N{sub 2} or O{sub 2}/CO{sub 2} conditions. Up to 15% of char burnout, the char particle diameters were reduced gradually. Up to 80% of char burnout, the char particle diameters were not changed. This is supposed that the chemical reaction is mainly occurred not on the external surface but on the internal surface of the char particle. Over 80% of char burnout, sudden shrinkage could be seen. Finally, an empirical equation for the prediction of the char particle shrinkage was introduced. Further investigation is required in high operating temperature, where CO{sub 2} gasification may have a large influence on the char burnout.

Controlled synthesis and photoluminescence properties of In{sub 2}O{sub 3} rods with dodecahedron In{sub 2}O{sub 3} microcrystals on top

Energy Technology Data Exchange (ETDEWEB)

Ouacha, Hassan [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh (Saudi Arabia); Hendaoui, Ali [Department of Physics, College of Science and General Studies, Alfaisal University, Riyadh (Saudi Arabia); Kleineberg, Ulf [Faculty of Physics, Ludwig Maximilian University of Munich, Garching (Germany); Albrithen, Hamad; Azzeer, Abdallah [Physics and Astronomy Department, King Saud University, Riyadh (Saudi Arabia)

2017-10-15

In{sub 2}O{sub 3} rods with dodecahedron In{sub 2}O{sub 3} microcrystals on top were synthesized in an electrical furnace via Au-catalyzed vapor transport process. A catalyst-assisted selective vapor-solid (VS) growth was proposed to explain the formation of the dodecahedron In{sub 2}O{sub 3} microcrystal, while the self-catalytic VS growth mechanism dominated the subsequent one-dimensional (1D) growth of the In{sub 2}O{sub 3} rod underneath the In{sub 2}O{sub 3} microcrystal. The structural evolution of these structures was carefully examined during the synthesis process by controlling the growth parameters. The morphologies, crystalline structures and surface chemistry were characterized by scanning electron microscopy (SEM), X-ray diffraction technique (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. The photoluminescence (PL) spectrum at room temperature of the as-grown In{sub 2}O{sub 3} structures exhibited both UV and blue luminescence emission under one excitation at 260 nm, which may be related to the existence of oxygen vacancies. The synthesized multifaceted In{sub 2}O{sub 3} microcrystal has shown to contain a large number of vertices and may find many applications in developing three-dimensional (3D) resonators. This work will not only enrich the synthesis science but also will open doors for applications of such structures in optical devices. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Multiphase flow modelling of furnace tapholes

OpenAIRE

Reynolds, Quinn G.; Erwee, Markus W.

2017-01-01

Pyrometallurgical furnaces of many varieties make use of tapholes in order to facilitate the removal of molten process material from inside the vessel. Correct understanding and operation of the taphole is essential for optimal performance of such furnaces. The present work makes use of computational fluid dynamics models generated using the OpenFOAM® framework in order to study flow behaviour in the taphole system. Single-phase large-eddy simulation models are used to quantify the discharge ...

Use of blast-furnace slag in making durable concrete for waste management repositories

Energy Technology Data Exchange (ETDEWEB)

Feldman, R. F.; Beaudoin, J. J. [National Research Council of Canada, Ottawa, ON (Canada); Philipose, K. E.

1991-02-15

Waste repositories for the belowground disposal of low-level radioactive waste rely greatly on the durability of concrete for their required 500-year service life. A research program is in progress based on laboratory testing of concretes containing either Type 1 cement or cements containing 65 and 75 percent of blast-furnace slag, each at 4 water-cement ratios. It has been established that the degradation of the concrete will depend on the rate of ingress of corrosive agents - chlorides, sulphate ions and CO{sub 2}. The ionic profiles and the kinetics of diffusion of these ions in the concretes have been measured by Secondary Electron Microscope (SEM) and Energy Dispersive X-ray Analysis (EDXA) techniques, and the results plotted according to a mathematical model. Predictions for service life of the concrete have been made from this model. These predictions have been correlated with properties of the concrete obtained from micro-structural, thermochemical and permeability measurements. The improvements in concrete durability due to blast-furnace slag additions are illustrated and discussed.

The fate of high redshift massive compact galaxies in dense environments

Energy Technology Data Exchange (ETDEWEB)

Kaufmann, Tobias; /Zurich, ETH; Mayer, Lucio; /Zurich U.; Carollo, Marcella; /Zurich, ETH; Feldmann, Robert; /Fermilab /Chicago U., KICP

2012-01-01

Massive compact galaxies seem to be more common at high redshift than in the local universe, especially in denser environments. To investigate the fate of such massive galaxies identified at z {approx} 2 we analyse the evolution of their properties in three cosmological hydrodynamical simulations that form virialized galaxy groups of mass {approx} 10{sup 13} M{sub {circle_dot}} hosting a central massive elliptical/S0 galaxy by redshift zero. We find that at redshift {approx} 2 the population of galaxies with M{sub *} > 2 x 10{sup 10} M{sub {circle_dot}} is diverse in terms of mass, velocity dispersion, star formation and effective radius, containing both very compact and relatively extended objects. In each simulation all the compact satellite galaxies have merged into the central galaxy by redshift 0 (with the exception of one simulation where one of such satellite galaxy survives). Satellites of similar mass at z = 0 are all less compact than their high redshift counterparts. They form later than the galaxies in the z = 2 sample and enter the group potential at z < 1, when dynamical friction times are longer than the Hubble time. Also, by z = 0 the central galaxies have increased substantially their characteristic radius via a combination of in situ star formation and mergers. Hence in a group environment descendants of compact galaxies either evolve towards larger sizes or they disappear before the present time as a result of the environment in which they evolve. Since the group-sized halos that we consider are representative of dense environments in the {Lambda}CDM cosmology, we conclude that the majority of high redshift compact massive galaxies do not survive until today as a result of the environment.

The Automation Control System Design of Walking Beam Heating Furnace

Directory of Open Access Journals (Sweden)

Hong-Yu LIU

2014-10-01

Full Text Available Combining the transformation project of certain strip steel rolling production line, the techniques process of walking beam heating furnace was elaborated in this paper. The practical application of LOS-T18-2ZC1 laser detector was elaborated. The network communication model of walking beam heating furnace control system was designed. The realization method of production process automation control was elaborated. The entire automation control system allocation picture and PLC power distribution system picture of walking beam heating furnace were designed. Charge machine movement process was elaborated. Walking beam movement process was elaborated. Extractor movement process was elaborated. The hydraulic station of walking mechanism was elaborated. Relative control circuit diagram was designed. The control function of parallel shift motor, uplifted and degressive motor was elaborated. The control circuit diagram of parallel shift motor of charge machine and extractor of first heating furnace was designed. The control circuit diagram of uplifted and degressive motor of charge machine and extractor of first heating furnace was designed. The realization method of steel blank length test function was elaborated. The realization method of tracking and sequence control function of heating furnace field roller were elaborated. The design provides important reference base for enhancing walking beam heating furnace control level.

Modeling of aerodynamics in vortex furnace

Energy Technology Data Exchange (ETDEWEB)

Anufriev, I.; Krasinsky, D. [Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Thermophysics; Salomatov, V.; Anikin, Y.; Sharypov, O. [Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Thermophysics; Novosibirsk State Univ. (Russian Federation); Enkhjargal, Kh. [Mongol Univ. of Science and Technology, Ulan Bator (Mongolia)

2013-07-01

At present, the torch burning technology of pulverized-coal fuel in vortex flow is one of the most prospective and environmentally-friendly combustion technologies of low-grade coals. Appropriate organization of aerodynamics may influence stability of temperature and heat flux distributions, increase slag catching, and reduce toxic emissions. Therefore, from scientific point of view it is interesting to investigate aerodynamics in the devices aiming at justification of design and operating parameters for new steam generators with vortex furnace, and upgrade of existing boiler equipment. The present work is devoted to physical and mathematical modeling of interior aerodynamics of vortex furnace of steam generator of thermal power plants. Research was carried out on the air isothermal model which geometry was similar to one section of the experimental- industrial boiler TPE-427 of Novosibirsk TPS-3. Main elements of vortex furnace structure are combustion chamber, diffuser, and cooling chamber. The model is made from organic glass; on the front wall two rectangular nozzles (through which compressed air is injected) are placed symmetrically at 15 to the horizon. The Laser Doppler Velocimeter LAD-05 was used for non-contact measurement of vortex flow characteristics. Two velocity components in the XY-plane (in different cross- sections of the model) were measured in these experiments. Reynolds number was 3.10{sup 5}. Numerical simulation of 3-D turbulent isothermal flow was performed with the use of CFD package FLUENT. Detailed structure of the flow in vortex furnace model has been obtained in predictions. The distributions of main flow characteristics (pressure, velocity and vorticity fields, turbulent kinetic energy) are presented. The obtained results may be used at designing boilers with vortex furnace. Computations were performed using the supercomputer NKS-160.

46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or combustion... wall of a stayed furnace or combustion chamber, the defective portion of the plate shall be cut away...

ELECTRICAL RESISTIVITY AND SEEBECK COEFFICIENT IN Ca(LaMnO COMPOUNDS PREPARED BY SOLID STATE REACTION METHOD

Directory of Open Access Journals (Sweden)

Jorge I. Villa

2017-01-01

Full Text Available By using the solid state reaction method samples of  Ca1-xLaxMnO3 (0 ≤ x ≥ 0.15 were prepared. Their transport properties were studied by electrical resistivity rho(T and Seebeck coefficient S(T measurements as a function of temperature and lanthanum content, in the temperature range between 100 and 290K. The structural and morphological properties were studied by X-ray diffraction analysis (XRD and scanning electron microscopy (SEM, respectively. The Seebeck coefficient is negative throughout the studied temperature range indicating a conduction given by negative charge carriers, its magnitude decreases with the lanthanum content from |-261| mV/K to |-120| mV/K. The electrical resistivity shows a semiconducting behavior, it was interpreted in terms of small polaron hopping model. Thermoelectric properties of the obtained compounds were studied by the thermoelectric power factor PF, which reaches maximum values around 2mW/K2cm, these values become this kind of ceramics promising thermoelectric compound, to be used in technological applications.

High-throughput exploration of thermoelectric and mechanical properties of amorphous NbO{sub 2} with transition metal additions

Energy Technology Data Exchange (ETDEWEB)

Music, Denis, E-mail: music@mch.rwth-aachen.de; Geyer, Richard W.; Hans, Marcus [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen (Germany)

2016-07-28

To increase the thermoelectric efficiency and reduce the thermal fatigue upon cyclic heat loading, alloying of amorphous NbO{sub 2} with all 3d and 5d transition metals has systematically been investigated using density functional theory. It was found that Ta fulfills the key design criteria, namely, enhancement of the Seebeck coefficient and positive Cauchy pressure (ductility gauge). These quantum mechanical predictions were validated by assessing the thermoelectric and elastic properties on combinatorial thin films, which is a high-throughput approach. The maximum power factor is 2813 μW m{sup −1} K{sup −2} for the Ta/Nb ratio of 0.25, which is a hundredfold increment compared to pure NbO{sub 2} and exceeds many oxide thermoelectrics. Based on the elasticity measurements, the consistency between theory and experiment for the Cauchy pressure was attained within 2%. On the basis of the electronic structure analysis, these configurations can be perceived as metallic, which is consistent with low electrical resistivity and ductile behavior. Furthermore, a pronounced quantum confinement effect occurs, which is identified as the physical origin for the Seebeck coefficient enhancement.

Relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn: Consistent parameterization and prediction of Seebeck coefficients

Science.gov (United States)

Shi, Guangsha; Kioupakis, Emmanouil

2018-02-01

We apply density functional and many-body perturbation theory calculations to consistently determine and parameterize the relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn, and predict the Seebeck coefficient as a function of doping and temperature. The quasiparticle band gaps, including spin-orbit coupling effects, are determined to be 0.728 eV, 0.555 eV, and 0.142 eV for Mg2Si, Mg2Ge, and Mg2Sn, respectively. The inclusion of the semicore electrons of Mg, Ge, and Sn in the valence is found to be important for the accurate determination of the band gaps of Mg2Ge and Mg2Sn. We also developed a Luttinger-Kohn Hamiltonian and determined a set of band parameters to model the near-edge relativistic quasiparticle band structure consistently for all three compounds that can be applied for thermoelectric device simulations. Our calculated values for the Seebeck coefficient of all three compounds are in good agreement with the available experimental data for a broad range of temperatures and carrier concentrations. Our results indicate that quasiparticle corrections are necessary for the accurate determination of Seebeck coefficients at high temperatures at which bipolar transport becomes important.

Alkali-activated blast furnace slag-zeolite cements and concretes

International Nuclear Information System (INIS)

Rakhimov, R.; Rakhimova, N.

2012-01-01

The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

Similarity of Ferrosilicon Submerged Arc Furnaces With Different Geometrical Parameters

Directory of Open Access Journals (Sweden)

Machulec B.

2017-12-01

Full Text Available In order to determine reasons of unsatisfactory production output regarding one of the 12 MVA furnaces, a comparative analysis with a furnace of higher power that showed a markedly better production output was performed. For comparison of ferrosilicon furnaces with different geometrical parameters and transformer powers, the theory of physical similarity was applied. Geometrical, electrical and thermal parameters of the reaction zones are included in the comparative analysis. For furnaces with different geometrical parameters, it is important to ensure the same temperature conditions of the reaction zones. Due to diverse mechanisms of heat generation, different criteria for determination of thermal and electrical similarity for the upper and lower reaction zones were assumed contrary to other publications. The parameter c3 (Westly was assumed the similarity criterion for the upper furnace zones where heat is generated as a result of resistive heating while the parameter J1 (Jaccard was assumed the similarity criterion for the lower furnace zones where heat is generated due to arc radiation.

In{sub 2}O{sub 3} microcrystals obtained from rapid calcination in domestic microwave oven

Energy Technology Data Exchange (ETDEWEB)

Motta, F.V., E-mail: fabiana@liec.ufscar.br [LIEC, IQ, UNESP, Rua Francisco Degni s/n, CEP 14801-907 Araraquara, SP (Brazil); Lima, R.C. [IQ, UFU, Av. Joao Naves de Avila, 2121, CEP 38400-902 Uberlandia, MG (Brazil); Marques, A.P.A.; Leite, E.R. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 Sao Carlos, SP (Brazil); Varela, J.A.; Longo, E. [LIEC, IQ, UNESP, Rua Francisco Degni s/n, CEP 14801-907 Araraquara, SP (Brazil)

2010-11-15

The simple way to prepare In{sub 2}O{sub 3} microcrystals is reported in this paper. The precursor, In(OH){sub 3} microstructures, were obtained using the Microwave-Assisted Hydrothermal (MAH) Method. By annealing as-prepared In(OH){sub 3} precursor at 500 {sup o}C for 5 min in a domestic microwave oven (MO), In{sub 2}O{sub 3} microcrystals were prepared, inheriting the morphology of their precursor while still slightly distorted and collapsed due to the In(OH){sub 3} dehydration process which was studied by thermal analysis. The In(OH){sub 3} and In{sub 2}O{sub 3} were characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Raman spectroscopy. These techniques confirm the chemical dehydration of In(OH){sub 3} and the formation of In{sub 2}O{sub 3} powders. The domestic MO promotes a rapid structural organization as compared with a CF (conventional furnace). The MAH method and the subsequent annealing in a domestic MO were shown to be a low cost route for the production of In{sub 2}O{sub 3}, with the advantages of lower temperature and smaller time.

Achievement report for fiscal 1999 on project for supporting the formation of energy/environmental technology verification project. International joint verification research project (Verification project relative to ignition and NOx reduction using plasma sub-burner in pulverized coal-fired furnace); 1999 nendo plasma sabubana ni yoru bifuntan nenshoro ni okeru chakka oyobi NO{sub x} teigen gijutsu ni kansuru jissho project seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

This project is executed through the cooperation of a Russian research institute, Akita Prefectural University, and the Ishikawajima-Harima Heavy Industries Co., Ltd. In the development of a plasma sub-burner and the basic research for its verification, a pulverized coal burning plasma sub-burner is designed and fabricated, a basic burning experiment is conducted for the plasma sub-burner, and plasma stabilization in a pulverized coal flow is simulated. In the verification study of the ignition by the plasma sub-burner in a pulverized coal-fired furnace, it is found that the newly-developed plasma sub-burner satisfies the prescribed operating conditions in the system and that the ignition of pulverized coal takes place across the air ratio range of 0.5-1.5 when pulverized coal is fed to the sub-burner. It is also found that NOx is reduced a great deal when a plasma operating on an orifice gas of air or nitrogen is generated in a gas which contains NOx. (NEDO)

Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

Energy Technology Data Exchange (ETDEWEB)

Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2012-12-01

The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO<sub>2sub> kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

Numerical analysis of loads effect on combustion performance and NO{sub x} emissions of a 220 MW pulverized coal boiler

Energy Technology Data Exchange (ETDEWEB)

Li, Jun; Yang, Weihong; Blasiak, Wlodzimierz [Royal Institute of Technology (KTH), Stockholm (Sweden). Div. of Energy and Furnace Technology; Jankowski, Radoslaw; Kotecki, Michal; Szewczyk, Dariusz [Industrial Combustion Systems (ICS) Company, Poznan (Poland); Brzdekiewicz, Artur [Remak-Rozruch SA, Opole (Poland)

2013-07-01

This paper presents numerical study on the combustion performance and NO{sub x} emissions of a 220 MW pulverized coal boiler. Three different loads have been simulated with combusting coal, 200, 170 and 140 MW, respectively. In order to get as precise as possible numerical analysis results, two-step simulation method has been adopted in this work, namely, air supply system simulation and furnace simulation. After air supply system simulation, the results have been taken as the initial and boundary conditions for furnace simulation. The comparison between the measured values and predicted results from 200 MW case shows much better agreement. According to the simulation results, the adopted two-step simulation method is reasonable and suitable for predicting the characters of the flow and combustion process. It is concluded that the distributions of temperature, O{sub 2} and CO concentration inside furnace with different loads shows good similarly. The total NOx emissions decreased with the boiler load reducing, and fuel NO{sub x} has the same trend as total NO{sub x}, and fuel NO{sub x} account for about 66% in total NO{sub x} in all the three cases. More important, thermal NO{sub x} slowly decreased with the rise of boiler load. More detailed results presented in this paper enhance the understanding of combustion processes and complex flow patterns of front-wall pulverized coal boilers.

Heat treatment of nuclear reactor pump part in integrated furnace facility

International Nuclear Information System (INIS)

Anon.

1983-01-01

A flexible heat treating system is meeting strict work specifications while accommodating the production flow pattern requirements and floor space needs of Advanced Metal Treating, Inc., Butler, Wis. Modular design and appropriate furnace configurations allow realization of the most efficient heat treat processing and energy use in a relatively small production area. The totally-integrated system (Pacemaker--manufactured by Lindberg, A Unit of General Signal, Chicago) consists of an electric integral-quench furnace with companion draw furnaces, washer unit and a material transfer car. With its one-side, inout configuration, the furnace operates with a minimum of drawing and washing equipment. The integral-quench furnace has a work chamber dimension of 30 by 48 by 30 inches (76.2 x 122 x 76.2 cm). The firm has two of these units, plus three in-out draw furnaces, one washer, one transfer car and two endothermic gas generators

Characterization of electric arc furnace dust aiming reuse; Caracterizacao da poeira de aciaria eletrica visando o seu reaproveitamento

Energy Technology Data Exchange (ETDEWEB)

Grillo, F.F.; Oliveira, E.B.G.; Oliveira, J.R. de, E-mail: fgrillo@ifes.edu.b [Instituto Federal de Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Telles, V.B.; Tenorio, J.A.S. [Universidade de Sao Paulo (USP), SP (Brazil)

2010-07-01

This work aims to study the characterize of steelmaking dust, from the primary refining of steel in Electric Arc Furnace, in order to verify feasibility of reuse through the addition of hot metal in the form of briquette. The techniques used to characterize the dust was chemical analyses, size separation tests, X-ray diffraction analyses (XRD), Scanning Electron Microscopy (SEM). After characterization, was the calculation of reductant considering the complete reduction of iron oxides and then to briquetting. The waste sample is composed essentially of spherical particles and has a very small particle size (85% below 10 {mu}m). The XRD has presented compounds such as ZnFe{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, ZnO e SiO{sub 2}. This work showed that its possible recovery approximately 92% of metal iron from dust generated during steelmaking.This (author)

Comparison of possibilities the blast furnace and cupola slag utilization by concrete production

Directory of Open Access Journals (Sweden)

D. Baricová

2010-04-01

Full Text Available In process of pig iron and cast iron production secondary raw materials and industrial wastes are formed The most abundant secondaryproduct originating in these processes are furnace slag. Blast furnace slag and cupola furnace slag originates from melting of gangue parts of metal bearing materials, slag forming additions and coke ash. In general, slag are compounds of oxides of metallic and non-metallic elements, which form chemical compounds and solutions with each other and also contain small volume of metals, sulfides of metals and gases. Chemical, mineralogical and physical properties of slag determinate their utilisation in different fields of industry.The paper presents results from the research of the blast furnace and cupola furnace slag utilization in the concrete production. Pilotexperiments of the concrete production were performed, by that the blast furnace and cupola furnace slag with a fractions of 0–4mm;4–8mm; 8–16mm were used as a natural substitute. A cupola furnace slag and combination of the blast furnace and cupola furnace slagwere used in the experiments. The analysis results show that such concretes are suitable for less demanding applications.

Non-polluting steam generators with fluidized-bed furnaces

Energy Technology Data Exchange (ETDEWEB)

Brandes, H [Deutsche Babcock A.G., Oberhausen (Germany, F.R.)

1979-07-01

The author reports on a 35 MW steam generator with hard coal fluidized-bed furnace a planned 35 MW steam generator with flotation-dirt fluidized-bed furnace, and on planned steam generators for fluidized-bed firing of hard coal up to a steam power of about 200 MW.

Stability of medium range order in Al-based metallic glass compacted by severe plastic deformation

Energy Technology Data Exchange (ETDEWEB)

Kovács, Zs.; Henits, P. [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary); Varga, L.K. [Research Institute for Solid state Physics and Optics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Schafler, E. [Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, A-1090 Vienna (Austria); Révész, Á., E-mail: reveszadam@ludens.elte.hu [Department of Materials Physics, Eötvös University, P.O.B. 32, H-1518 Budapest (Hungary)

2013-06-05

Highlights: ► High pressure torsion has been applied to produce low-porosity bulk Al-based amorphous specimens. ► The compacted disks possess higher hardness than the original glass. ► Mechanical and thermal impacts have only minor effects on the glassy structure. ► Medium range order is an inherent feature of the amorphous state. -- Abstract: High pressure torsion has successfully been applied to produce low-porosity, bulk specimens from Al-based metallic glass ribbons (Al{sub 85}Y{sub 8}Ni{sub 5}Co{sub 2}, Al{sub 85}Ce{sub 8}Ni{sub 5}Co{sub 2} and Al{sub 85}Gd{sub 8}Ni{sub 5}Co{sub 2}). The compacted disks possess higher hardness than the original glass and have substantial glass fraction with nanocrystalline precipitations. Mechanical and thermal impacts have only minor effects on the glassy structure as demonstrated by the stability of the X-ray diffraction halo positions. Unchanged halos reveal that medium range order is a key characteristic of the amorphous state.

Determination of trace elements in paints by direct sampling graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Bentlin, Fabrina R.S. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil); Pozebon, Dirce [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil)], E-mail: dircepoz@iq.ufrgs.br; Mello, Paola A.; Flores, Erico M.M. [Departamento de Quimica, Universidade Federal de Santa Maria, UFSM, 97105-900 Santa Maria, RS (Brazil)

2007-10-17

A direct sampling graphite furnace atomic absorption spectrometric (DS-GFAAS) method for the determination of Cd, Pb, Cr, Ni, Co and Cu in paints has been developed. Serigraphy, acrylic and tattoo paints were analysed. Approaches like pyrolysis and atomization temperatures, modifiers and sample mass introduced in the atomizer were studied. Quantification was performed using calibration curves measured with aqueous standard solutions pipetted onto the platform. The sample mass introduced in the graphite tube ranged from 0.02 to 8.0 mg. Palladium was used as modifier for Cd, Pb and Cu, while Mg(NO{sub 3}){sub 2} was used for Co. For Ni determination, the graphite platform was covered with carbon powder. The characteristic masses of Cd, Pb, Cr, Ni, Co and Cu were 1.4, 22.5, 7.9, 11.0, 9.6 and 12.5 pg, while the limits of detection were 0.0004, 0.001, 0.03, 0.22, 0.11 and 0.05 {mu}g g{sup -1} of Cd, Pb, Cr, Ni, Co and Cu, respectively. The accuracy was determined by comparison of the results with those obtained by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS), using liquid sampling of digests. For matrix characterization, major and minor elements (Al, Mg, Ba, Ca, Cr, Cu, Pb, Sr, Ti and Mg) were determined by inductively coupled plasma optical emission spectrometry (ICP OES)

''Compact'' reversed-field pinch (CRFP) reactor design

International Nuclear Information System (INIS)

Miley, G.H.; Nebel, R.A.

1980-01-01

These results indicate that a CRFP operating in the range of 100 MWe should be feasible. While the large aspect ratio leads to a 6.4-m major radius, the design still retains many attributes of conventional compact tori, such as simplicity and ease of access. The relatively low Q/sub p/ with batch burns might be satifactory for a demonstration unit. However, to obtain power-plant ''grade'' Q/sub p/, either refueling (possibly by pellets) or larger size plasmas appear necessary

Multifold Seebeck increase in RuO2 films by quantum-guided lanthanide dilute alloying

International Nuclear Information System (INIS)

Music, Denis; Basse, Felix H.-U.; Schneider, Jochen M.; Han, Liang; Borca-Tasciuc, Theo; Devender; Gengler, Jamie J.; Voevodin, Andrey A.; Ramanath, Ganpati

2014-01-01

Ab initio predictions indicating that alloying RuO 2 with La, Eu, or Lu can increase the Seebeck coefficient α manifold due to quantum confinement effects are validated in sputter-deposited La-alloyed RuO 2 films showing fourfold α increase. Combinatorial screening reveals that α enhancement correlates with La-induced lattice distortion, which also decreases the thermal conductivity twentyfold, conducive for high thermoelectric figures of merit. These insights should facilitate the rational design of high efficiency oxide-based thermoelectrics through quantum-guided alloying

Fergusonite-type CeNbO{sub 4+δ}: Single crystal growth, symmetry revision and conductivity

Energy Technology Data Exchange (ETDEWEB)

Bayliss, Ryan D. [Department of Materials, Imperial College London, Prince Consort Road, London, SW7 2BP (United Kingdom); Pramana, Stevin S.; An, Tao; Wei, Fengxia; Kloc, Christian L. [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore); White, Andrew J.P. [Chemical Crystallography Laboratory, Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ (United Kingdom); Skinner, Stephen J. [Department of Materials, Imperial College London, Prince Consort Road, London, SW7 2BP (United Kingdom); White, Timothy J. [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore); Baikie, Tom, E-mail: tbaikie@ntu.edu.sg [School of Materials Science and Engineering, 50 Nanyang Avenue, Nanyang Technological University, 639798 (Singapore)

2013-08-15

Large fergusonite-type (ABO{sub 4}, A=Ce, B=Nb) oxide crystals, a prototype electrolyte composition for solid oxide fuel cells (SOFC), were prepared for the first time in a floating zone mirror furnace under air or argon atmospheres. While CeNbO{sub 4} grown in air contained CeNbO{sub 4.08} as a minor impurity that compromised structural analysis, the argon atmosphere yielded a single phase crystal of monoclinic CeNbO{sub 4}, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy conducted under argon found that stoichiometric CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+δ} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. - Graphical abstract: Large fergusonite-type CeNbO{sub 4} crystals were prepared for the first time in a floating zone mirror furnace. Crystal growth in an argon atmosphere yielded a single phase monoclinic CeNbO4, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy found CeNbO{sub 4} single crystals showed lower conductivity compared to CeNbO{sub 4+δ} confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides. Highlights: • Preparation of single crystals of CeNbO{sub 4} using a floating zone mirror furnace. • Correction to the crystal symmetry of the monoclinic form of CeNbO{sub 4}. • Report the conductivity of a single crystal of CeNbO{sub 4}.

Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures

Directory of Open Access Journals (Sweden)

Ken-ichi Uchida

2014-11-01

Full Text Available We report temperature-dependent measurements of longitudinal spin Seebeck effects (LSSEs in Pt/Y_{3}Fe_{5}O_{12} (YIG/Pt systems in a high temperature range from room temperature to above the Curie temperature of YIG. The experimental results show that the magnitude of the LSSE voltage in the Pt/YIG/Pt systems rapidly decreases with increasing the temperature and disappears above the Curie temperature. The critical exponent of the LSSE voltage in the Pt/YIG/Pt systems at the Curie temperature is estimated to be 3, which is much greater than that for the magnetization curve of YIG. This difference highlights the fact that the mechanism of the LSSE cannot be explained in terms of simple static magnetic properties in YIG.

Magnetic and microstructural properties of Fe{sub 3}O{sub 4}-coated Fe powder soft magnetic composites

Energy Technology Data Exchange (ETDEWEB)

Jo Sunday, Katie [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States); Hanejko, Francis G. [Hoeganaes Corporation, Cinnaminson, NJ08077 (United States); Taheri, Mitra L., E-mail: mtaheri@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States)

2017-02-01

Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and possess high melting temperatures, thus providing adequate electrical barriers between metallic particles. In this work, iron powder was coated with Fe{sub 3}O{sub 4} particles via mechanical milling, then compacted and cured in an inert gas environment. We find density and coercivity to improve with increasing temperatures; however, core loss greatly increases, which is attributed to the formation of a more conductive iron-oxide phase and less resistive Fe volume. Our work begins to exemplify the unique qualities and potential for ferrite-based coatings using traditional powder metallurgy techniques and higher curing temperatures for electromagnetic devices. - Highlights: • Fe{sub 3}O{sub 4}-coated Fe powder was produced via mechanical milling, then compacted and cured into composite form. • SEM/EDS confirm Fe particles are individually isolated with iron-oxide coating material. • Larger particle sizes show improved core loss and coercivity measurements. • We report good magnetic properties for compaction at 800 MPa and a curing temperature of 700 °C.