Revolving type fluidized-bed technology, developed by Ebara Corp., is installed in more than 100 facilities worldwide. The technology is applied for waste, coal and in situations where a conventional fluidizedbed is difficult to use. Waste and/or coal can be treated and valuable energy can be recovered from a non-renewable source. This paper describes the application of the revolving fluidizedbed for waste, coal and tyres.
The purpose of this project was to investigate the origin of pressure fluctuations in fluidizedbed systems. The study assessed the potential for using pressure fluctuations as an indicator of fluidizedbed hydrodynamics in both laboratory scale cold-models and industrial scale boilers. Both bubbling fluidizedbeds and circulating fluidizedbeds were evaluated. Testing including both cold-flow models and laboratory and industrial-scale combustors operating at elevated temperatures. The study yielded several conclusions on the relationship of pressure fluctuations and hydrodynamic behavior in fluidizedbeds. The study revealed the importance of collecting sufficiently long data sets to capture low frequency (on the order of 1 Hz) pressure phenomena in ...
After the completion of the 4MWth pilot plant of the Pressurizied Internally Circulating Fluidized-bed Boiler (PICFB), a total of 15 test runs, amounting to 2280 hours of operation, were concluded. The test results have confirmed the superior operating performance. Additionally, Ebara plans to develop a Pressurized Internally Circulating Fluidized-bed Gasifier (PICFG or Advanced PICFB). 8 figs.
Fluidizedbed technology was experimentally evaluated for the combustion and gasification of cotton gin waste. The isothermal bed temperatures in the reactors could be maintained below the ash fusion point of the waste. Raw stripper harvested cotton gin trash could be metered directly into the fluidized-bed reactors indicating that little feed preparation is required. H and CO were the primary products of gasification, and approximately 3200-400 Btu of gas were produced per lb of cotton gin waste. These techniques offer the potential of providing small-scale energy conversion systems for use on farms.
In the atmospheric pressure coal combustion area, the internally circulating fluidizedbed boiler (ICFB) has already been proven to possess superior performance features in terms of the ease with which load conditions can be controlled and its low pollution level. Based on the particular merits of the ICFB furnace and the application of this technology to pressurized fluidizedbed boiler technology, it was possible to achieve a pressurized fluidizedbed boiler with superior ease of operation, reliability and los pollution characteristics. Cold model tests and computer simulation have been carried out to investigate the possibility of applying ICFB technology to the pressurized fluidizedbed boiler technology in an attempt to develop the pressurized internally circulating fluidized ...
In the atmospheric pressure coal combustion area, the Internally Circulating FluidizedBed Boiler (ICFB) had already been proven to possess superior performance features in terms of the ease with which load conditions can be controlled and because of its low pollution level. Based on the particular merits of the ICFB furnace and the application of this technology to pressurized fluidizedbed boiler technology, it was possible to achieve a pressurized fluidizedbed boiler with superior ease of operation, reliability and low-pollution characteristics. From fiscal 1992, the authors have conducted extensive research work, including cold model tests and computer simulations to investigate the possibility of applying ICFB technology to the pressurized fluidizedbed boiler technology in an attempt to develop the Pressurized ...
In 1980 Sasol completed its very large coal conversion complex, Sasol Two and Three in South Africa. This complex, the largest coal-to-liquids facility in the world, utilizes Sasol's proprietary Fischer-Tropsch technology, the Synthol Process. The two key elements of the Synthol Process are its catalyst and its unique fluidizedbed reactor, the Synthol Circulating FluidizedBed Reactor. Details on the catalytic aspects and reaction mechanism have been given elsewhere. In this paper, the history of the development of the reactor is discussed.
The coal-fired combined cycle with partial gasification and fluidizedbed combustion (PGFBC-CC), also referred to as a hybrid cycle, has advantages of staged energy conversion and utilization, which can attain high thermal efficiency with low emissions. Four kinds of PGFBC-CC are studied in this paper, two based on pressurized fluidizedbed combustion (PFBC) and two on atmospheric fluidizedbed combustion (AFBC). Thermal performance calculations and parametric analyses were performed. On the basis of the results, from the above analyses, the best integration system for China is suggested. In addition, a preliminary exergetic analysis is carried out for three of the PGFBC-CC variants.
This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period October 1, 2004 through December 31, 2004. The following tasks have been completed. First, the renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have proceeded well. Second, the detailed design of supporting and hanging structures for the CFBC was completed. Third, the laboratory-scale simulated fluidized-bed facility was modified after completing a series of pretests. The two problems identified during the pretest were solved. Fourth, the carbonization of chicken waste and coal was investigated in a tube furnace and a Thermogravimetric Analyzer (TGA). The experimental results from this study are presented in ...
This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2004 through September 30, 2004. The following tasks have been completed. First, renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have started. Second, the design if the component parts of the CFBC system have been reviewed and finalized so that the drawings may be released to the manufacturers during the next quarter. Third, the experiments for solid waste (chicken litter) incineration have been conducted using a Thermogravimetric Analyzer (TGA). This is in preparation for testing in the simulated fluidized-bed combustor. The experimental results from this study are presented in this report. Finally, ...
In the new system presented in this paper, the cement clinker is sintered, not in a rotary kiln, but in two different furnaces: a spouted bed kiln and a fluidizedbed kiln. The heat generated in the process of cooling the cement clinker is recovered by a fluidizedbed cooler and a packed bed cooler, which are more efficient than the conventional coolers. Compared with the rotary kiln system, the new technology significantly reduces NO{sub x} emissions, appreciably cuts energy consumption, and reduces CO{sub 2} emissions as well. Thus, the new system is an efficient cement sintering system that is friendly to the global environment. In this paper, we describe this new technology as one of the applied technologies at an industrial level that is being developed in the Clean Coal Technology Project, and we present the results from test operations at our pilot plant.
A fluidizedbed combustor of 0.146 m diameter and 1 m length was fabricated from stainless steel to burn olive cake. Initially, and in order to obtain fluidization, the system was operated under cold conditions using a sand with particle size in the range of 500 to 710 microns. The continuous combustion experiments were carried out under controlled conditions, such that the effects of bed temperature, olive cake feed rate, fluidization velocity, and particle size on combustion efficiency and flue gas composition were investigated. It was found that the combustion efficiency decreases with the bed temperature, fluidization velocity, and the feed rate, while it increases with the particle size used. Further, the gas products analysis carried out using a gas chromatography analyzer have shown a nonmeasured amount of SO2, and small amounts of ...
The objective of Phase IV of the contract is to design a conceptual flue gas treating unit based on the fluidized-bed Copper Oxide (FBCO) process for a new coal-fired 500 MW(e) power plant. A technical and economic evaluation of the FBCO process, based on the conceptual design, will also be completed. Progress is described.
Carbonaceous solid material such as coal is gasified in a fast fluidizedbed gasification system utilizing dual fluidizedbeds of hot char. The coal in particulate form is introduced along with oxygen-containing gas and steam into the fast fluidizedbed gasification zone of a gasifier assembly wherein the upward superficial gas velocity exceeds about 5.0 ft/sec and temperature is 1500.degree.-1850.degree. F. The resulting effluent gas and substantial char are passed through a primary cyclone separator, from which char solids are returned to the fluidizedbed. Gas from the primary cyclone separator is passed to a secondary cyclone separator, from which remaining fine char solids are returned through an injection nozzle together with additional steam and oxygen-containing gas to an oxidation zone located at the bottom of ...
A literature review on gasification of lignocellulosic biomass in various types of fluidizedbed gasifiers is presented. The effect of several process parameters such as catalytic bed material, bed temperature and gasifying agent on the performance of the gasifier and quality of the producer gas is discussed. Based on the priorities of researchers, the optimum values of various desired outputs in the gasification process including improved producer gas composition, enhanced LHV, less tar and char content, high gas yield and enhanced carbon conversion and cold gas efficiency have been reported. The characteristics and performance of different fluidizedbed gasifiers were assessed and the obtained results from the literature have been extensively reviewed. Survey of literature revealed that several industrial biomass gasification plants using ...
Hydrodynamic regimes and characteristics of air-sand flow were studied in a cone-shape swirling fluidizedbed for two types of air entry, or swirl generator: through a four-nozzle system (tangential entry) and using an annular-spiral air distributor (axial entry). Quartz sand of four particle sizes, 180-300, 300-500, 500-600 and 850-1180mm, was used as the bed material in experimental tests on a cold model of a conical swirling fluidizedbed combustor. During each test run, the pressure drop across the bed (Dp) was measured versus superficial velocity at the lower bed basis (u) for three static bed heights (20, 30 and 40cm). Four regimes were found in the bed behavior for both swirl generators. The Dp-u diagrams were compared between tangential and axial air entries for different operating...
The paper reports a work-in-progress outlook of a R and D project aimed at developing an advanced boiler for the combustion of virgin and exhaust olive husks at small scale. Fluidizedbed technology has been preferred because of its well known advantages that include large thermal inertia, high combustion efficiency, low NOx emissions and considerable heat transfer rate. A 100 kW atmospheric bubbling fluidizedbed combustor has been designed and built. The facility is equipped with devices for continuous fuel feeding as well as heat extraction from the bed region. Measurements of temperature and gas concentrations are obtained by using thermocouples and gas-analyzer. Steady state tests of combustion were carried out at typical fluidizedbed combustion temperatures. Tests proved that not only exhaust olive husks but also the virgin ones - ...
The fossil fuel consumption and pollutant emissions in a coal fired fluidizedbed boiler could be reduced by biomass pyrolysis gas reburning. The influence of three kinds of biomass pyrolysis gases on the emission of N2O in a laboratory scale fluidizedbed was investigated using the mechanism of GRI3.0 in this paper. The results showed that: the effect of sawdust pyrolysis gas reburning on N2O was more significant than that of rice husk and orange peel under the same conditions; the increase of initial oxygen content from 1% to 8% in flue gas would restrain the decomposition of N2O; the N2O decomposition was enhanced by increasing reaction temperature from 1073.15 K to 1323.15 K, and the decomposition rate may reach 99% at 1223.15 K.
Trying to achieve the optimal utilization of oil shale resources, and the production of a more environmentally acceptable fuel, as well as a solid waste with a low a sulphur content, thereby reducing acidic leachates, has led to this investigation. In this article, the influences of the bed temperature and the choice of fluidizing gas on the quality and quantity of the produced fuel gas, using a continuous feed fluidizedbed reactor, were investigated. The composition and calorific value of the generated gas were determined. There was a nearly linear increase in the amount of fuel gas produced as a function of temperature, reaching {approx}350 kg per 10{sup 3} kg of dry raw shale and the gross calorific value ranged from 15 to 23 MJ-kg{sup -1} with CO and H{sub 2} being the major constituents. Subsequent experiments were carried out, employing a thermogravimetric analyser under similar conditions as ...
The technology being evaluated is the Modified In-Situ (MIS) retorting process for raw shale oil production, combined with a Circulating FluidizedBed Combustor (CFBC), for the recovery of energy from the mined shale. (VC)
The technology being evaluated is the Modified In-Situ (MIS) retorting process for raw shale oil production, combined with a Circulating FluidizedBed Combustor (CFBC), for the recovery of energy from the mined shale. (VC)
This purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period April 1, 2005 through June 30, 2005. The following tasks have been completed. First, the new Combustion Laboratory was occupied on June 15, 2005, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final painting stage. Second, the fabrication and manufacturing contract for the CFBC Facility was awarded to Sterling Boiler & Mechanical, Inc. of Evansville, Indiana. Sterling is manufacturing the assembly and component parts of the CFBC system. The erection of the CFBC system is expected to start September 1, 2005. Third, mercury emissions from the cofiring of coal and chicken waste was studied experimentally in the laboratory-scale simulated ...
This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2005 through March 31, 2005. The following tasks have been completed. First, the renovation of the new Combustion Laboratory is nearly complete, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final stages. Second, the fabrication and manufacture of the CFBC Facility is being discussed with a potential contractor. Discussions with potential contactor regarding the availability of materials and current machining capabilities have resulted in the modification of the original designs. The selection of the fabrication contractor for the CFBC Facility is expected during the next quarter. Third, co-firing experiments conducted with coal and chicken waste ...
Various volume-reduction methods are discussed and their capabilities evaluated. The following volume-reduction methods have the greatest potential at this time: forced-circulation evaporator/crystallizer; incinerator (conventional type); compactor; fluidized-bed calciner/incinerator; fluidized-bed dryer/incinerator; thin-film evaporator; extruder/evaporator; drum mixer; ribbon blender; inert-carrier evaporative process; molten-glass incinerator. The first eight system types listed above have been improved to the point of commercial viability.
Processes of production and purification (necessary for fabricating fuel elements) of powdery uranium dioxide with particle size up to 1000 #mu#m and more have been studied. Developed is continuous process of UO_2 production with above particle size by converting uranium hexafloride into UO_2 solid particles in fluidizedbed while their interaction with water vapor and hydrogen on the uranium dioxide nucleus material. The method allows to conduct continuous selection from the apparatus of UO_2 powder fraction with particle size near 1000 #mu#m without nucleus material additional feed.
With relation to the coals delivered as common samples in the coal fundamental technology development project, an experimental study was conducted on agglomeration characteristics and reaction characteristics in the fluidized-bed coal gasifier. For the experiment, used was a fluidizedbed gasifier inserted with a cone-shape dispersion plate with a nozzle in the center. After raising the temperature of the gasifier up to 773K, gasification was conducted sending to the gasifier air from the nozzle and steam from the dispersion plate. The mean particle diameter and gas concentration of chars were measured till the temperature reaches 1373K. As a result of the experiment, it was confirmed that the carbon conversion ratio increases with a decrease in coalification degree of the coal. Moreover, influence of the coal kind was markedly observed at the grid zone of the lower part of the bed, and it was clarified ...
This paper presents the results of experimental investigations of the ignition and combustion of plant biofuels (wood particles, date stones) and products of their mechanical and thermal treatment (pellets, charcoal) at temperatures typical of the burning process in nonforced furnaces and fixed-bed and fluidized-bed gas producers. The influence of the furnace heat treatment of a fuel on its inflammation and combustion has been revealed. The results have been compared with the known data on the burning of pellets, brown coals, and anthracites and with the calculation by the classical diffusion-kinetic model.
This work reports an experimental study on the steam gasification of an anthracite coke in a fluidizedbed reactor, with the aim of evaluating the reaction kinetics. Isothermal runs were carried out with samples of 91 to 275 g of coke, at temperatures between 799 and 928{sup 0}C and for steam partial pressures between 0.3 and 0.9 atm. The conversion decreases as the amount of coke is increased and it is very sensitive to the temperature. Neither the volumetric reaction model nor the unreacted shrinking core model can satisfactorily fit the experimental results. That is why empirical models have been used. The first one is derived from the unreacted shrinking core model. An activation energy of 219 kJ. mol{sup -1} and a reaction order with respect of steam of 0.57 have been identified. In the second model, the conversion has been correlated as a function of a dimensionless time. A comparison of the results obtained in the ...
Functionalizing nanoparticle surfaces is essential for achieving homogeneous dispersions of monodisperse particles in polymer nanocomposites for successful utilization in engineering applications. Functionalization reduces the surface energy of the nanoparticles, thereby limiting the tendency to agglomerate. Moreover, reactive groups on the surface can also participate in the polymerization, creating covalent bonds between the inorganic and organic phases. In this paper, a fluidizedbed inductively coupled plasma (FB-ICP) reactor is used to break apart the agglomerates and functionalize commercial TiO2 nanoparticle powders in a batch of several grams. The fluidizedbed could be implemented into a continuous flow reactor, potentially making this a viable method to treat larger quantities of commercial powders. The particles are treated with acrylic acid (AA) and tetraethylorthosilicate (TEOS) plasma and ...
The growth kinetics constants and concentration of active attached biomass in an anaerobic fluidizedbed which decomposes acetic, propionic and butyric acid were estimated. The mixture of above mentioned fatty acids was supplied to the fluidizedbed in the range of hydraulic retention time (HRT) from 0.25 to 2 days. After the effluent reached in a steady state in quality, batch experiments were conducted separately with each fatty acid as a substrate in order to investigate the decomposition characteristics of each substrate by attached biomass. In order to estimate the parameter values of the growth kinetics of the bacteria, batch experiments were also conducted under the completely mixed condition using detached biomass from a support material. The changes of fatty acid concentrations with time were clearly expressed with the Monod growth model. Maximum specific substrate decomposition rates and ...
In the future fossil fuelled power plants are realised/laid down as combined cycle power plants with high current generation efficiencies. The method of pressure fluidized-bed combustion with downstream hot gas cleaning is going to compete with methods combined with a pressure coal gasification or a pressure dust combustion. The advantages of the pressure fluidizedbed combustion are the simpler method set-up and consequently lower investment costs. (orig./CD) [Deutsch] Kohlegefeuerte Kraftwerke werden zukuenftig als kombinierte Gas/Dampfturbinen-Kraftwerke mit hohen Stromerzeugungswirkungsgraden ausgefuehrt werden. Das Verfahren der Druckwirbelschichtverbrennung mit nachgeschalteter Heissgasreinigung und Rauchgasturbine wird dabei mit Verfahren mit einer vorgeschalteten Kohledruckvergasung oder mit einer Druckstaubfeuerung konkurrieren. Die Vorteile der Druckwirbelschichtverbrennung liegen dabei auf dem insgesamt ...
Experimental and theoretical investigation on drying of a single coal particle in fluidizedbed combustor is presented. Coal particle drying was considered via the moist shrinking core mechanism. The results of the drying test runs of low-rank Serbian coals were used for experimental verification of the model. The temperature of the coal particle center was measured, assuming that drying was completed when the temperature equalled 100{sup o}C. The influence of different parameters (thermal conductivity and specific heat capacity of coal, fluidizedbed temperature, moisture content and superheating of steam) on drying time and temperature profile within the coal particle was analyzed by a parametric analysis. The experimentally obtained results confirmed that the moist shrinking core mechanism can be applied for the mathematical description of a coal particle drying, while dependence between drying time ...
The Coal Fired Combined Cycle (CFCC) power system thermodynamic cycle is illustrated schematically. Pressurized air supplied at the discharge of gas turbine compressors is ducted to the pressure vessel of pressurized, fluidized-bed, combustor-steam generator modules. The air is introduced in parallel to the beds, entering through distribution grids beneath each bed. Steam generation tubes are buried within the beds and are also arranged as membrane tube walls enclosing the four sides. Crushed coal (1/4 inch x 0) is pneumatically fed at locations just above the air inlet grids at the bottom of each bed. Dolomite is similarly fed to the individual beds. The coal is burned at a temperature below the ash fusion point. Sulfur is removed in the fluid beds through reaction of the SO/sub 2/ with CaCO/sub 3/ and O/sub 2/ to form solid CaSO/sub 4/ and ...
Sasol, a South-African company, has converted coal into synthetic fuels for 40 years; in order to increase by 6 pc its annual production (40 Mt coal are processed), Sasol has launched the Sky High project and intends to replace the ancient Sasol Synthol reactors by Advanced Synthol reactors using conventional fluidizedbeds instead of circulating fluidizedbeds. Coal is first gasified under high pressure and high temperature conditions (the Secunda site uses the Fischer-Tropsch conversion process) and is then processed in the reactor through a single phase process using an iron-base catalyst, leading to significant cost reductions.
Co-combustion of chicken litter with coal was performed in a laboratory-scale fluidizedbed combustor to investigate the effect of chicken litter addition on the partitioning behavior of mercury. Gaseous total and elemental mercury concentrations in the flue gas were measured online, and ash was analyzed for particle-bound mercury along with other elemental and surface properties. The mercury mass balance was between 85 and 105%. The experimental results show that co-combustion of chicken litter decreases the amount of elemental and total mercury in the gas phase. Mercury content in fly ash increases with an increasing chicken litter share. 22 refs., 6 figs., 5 tabs.
Operation and maintenance cost estimating methodologies for advanced coal-fired atmospheric circulating fluidized-bed and advanced natural gas-fired combined cycle electric power plants are presented. The purpose of these cost estimating relationships is for use in long range planning and evaluation of the economics of use of these technologies for electric power generation. Projected annual costs of reference plants at ten different sites in the United States, one in each of the ten DOE regions, are given as of 1989, and comparisons are made with existing technologies. A listing of a computer program implementing the methodologies is included. 14 refs., 4 figs., 13 tabs.
Combustion characteristics of Korean anthracite in a circulating fluidizedbed and freeboard were investigated. A test coal was selected with heating value of 4,429kcal/kg and ash content of 38%. Characteristics of combustion, sorbent effect on desulphurisation and emission of SO{sub x} and NO{sub x} were monitored by varying process variables such as feed rate, (Ca+K)/S ratio, and excess air ratio at the given properties of coal. Optimum operating conditions were studied by analysing: axial profiles of temperature, effect of excess air ratio, characteristics of loopseal and bag filter ashes, and emission of toxic gases. 9 refs., 9 figs., 3 tabs.
Both the KRW fluidized-bed gasifier and the transport gasifier case studies were used for this assessment. The transport technology is a high-velocity circulating fluidized-bed reactor currently under development by The M.W. Kellogg Company. In the earlier assessment, seven design concepts or cases were identified; a process design was developed; major equipment items were identified; estimates of capital cost, operation and maintenance cost, and cost of electricity were developed; reliability was predicted; and development issues were identified for six studies. Three of the most probable cases were further evaluated for a Greenfield assessment in this report to adequately determine all costs independent of facilities at Plant Wansley.
Both the KRW fluidized-bed gasifier and the transport gasifier case studies were used for this assessment. The transport technology is a high-velocity circulating fluidized-bed reactor currently under development by The M.W. Kellogg Company. In the earlier assessment, seven design concepts or cases were identified; a process design was developed; major equipment items were identified; estimates of capital cost, operation and maintenance cost, and cost of electricity were developed; reliability was predicted; and development issues were identified for six studies. Three of the most probable cases were further evaluated for a Greenfield assessment in this report to adequately determine all costs independent of facilities at Plant Wansley.
This report summarizes the progress made on the development of an integrated multistage fluidizedbed retorting process (KENTORT II) during the period of October 1, 1992 through September 30, 1993 under Cooperative Agreement No. DE-FC21-90MC27286 with the Morgantown Energy Technology Center, US Department of Energy. The KENTORT II process includes integral fluidizedbed zones for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. The PDU was assembled, instrumented and tested during this fiscal year. Along with the major activity of commissioning the 50-lb/hr retort, work was also completed in other areas. Basic studies of the cracking and coking kinetics of model compounds in a fixed bed reactor were continued. Additionally, as part of the effort to investigate niche market ...
Describes the wastes produced and the waste disposal methods used at BEWAG power plants. Wastes covered include fly ash, fluidizedbed ash, gypsum from flue gas desulfurization and evaporation residues. Disposal methods include using ashes and gypsum to make building materials. Despite many years of experience in the utilization and disposal of residues from coal-fired power stations BEWAG have not encountered any disposal problems. 5 tabs.
The present invention provides an improvement in the art of combined steam turbine and gas turbine power plants of the type wherein the principal source of energy is a fluidizedbed combustor fueled by coal. More specifically, the invention pertains to supplemental firing of the gas turbine cycle with a clean hydrocarbon fuel (CHF) at a high incremental efficiency to significantly increase overall plant efficiency.
This paper reviews the mill flowsheet applied at the SOMAIR (Societe des Mines de l'Air) uranium mill in Niger. It focuses on the yellow cake quality improvements achieved by molybdenum and zirconium elimination through double yellow cake precipitation in tanks at first stage and through size/density control in a fluidizedbed precipitator at second stage. Water saving aspects in the plant are also presented. (author)
A steam producing system based on fluidized-bed gasification of biomass materials is discussed. Limited experimental results are discussed and show that steam has been produced at rates of 334.3 kg/hr. (737 lbs/hr.) with 2.8 kg of stream produced for each kilogram of cotton gin trash (2.8 lb/lb.). ref.
The systems analyses and optimization studies performed in connection with a program to design and evaluate a commercial 663 MWe coal-fired combined cycle power plant using pressurized fluidizedbed combustion and advanced technology in the hot gas cleanup system and gas turbines are presented. Details on the plant control system are included. (LCL)
A final report is presented on the design, environmental characteristics, performance and maintainability, and economic analysis of a commercial 663 MWe coal-fired combined cycle power plant using pressurized fluidizedbed combustion, and advanced technology in the hot gas cleanup system and gas turbines. Experimental data on the performance of each of the major components are included. (LCL)
This document contains the outline and viewgraphs used in the speech. Topics covered are: conventional oil and gas recovery; unconventional oil and gas sources; oil shale resources; conventional coal combustion; advanced fossil power systems; fluidizedbed combustion; coal/oil or coal/water mixtures; and gaseous and liquid fuels from coal. (DMC)
This paper presents a brief overview of refuse derived fuel (RDF) processing systems, and the different types of RDF. The quality of RDF, combustion of RDF in fluidizedbeds, and moving grate reactors, operating conditions, emissions (sulphur dioxide, nitrogen oxides, carbon monoxide and hydrogen chloride) and thermal efficiency are discussed. (UK).
This appendix contains the alphabetically indexed bibliography for the complete group of reports on municipal waste management alternatives. The references are listed for each of the following topics: mass burn technologies, RDF technologies, fluidized-bed combustion, pyrolysis and gasification of MSW, materials recovery- recycling technologies, sanitary landfills, composting, and anaerobic digestion of MSW.
The use of pressurised fluidized-bed coal combustion (fbc) in a combined cycle is seen as a most attractive technology for increasing the efficiency of electricity generation. The concept of pressurised fbc is described and the technical problems that are encountered in its operation and in limiting it to a gas turbine are discussed. Details are given of pilot plant facilities and current R and D programmes.
Spark ignition internal combustion engines perform satisfactorily when the fueled with biomass producer gas from a fluidizedbed gasifier. Although power output is reduced compared to natural gas levels, full power recovery can be achieved with a relatively low level of supercharging. Important considerations are an adequate fuel delivery system and adquate gas cleaning. ref.
The KENTORT II process includes integral fluidizedbed zones for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. Along with the major activity of assembling the components of the 50-lb/hr retort, work was also completed in other areas this quarter. Basic studies of the cracking and coking kinetics of model compounds in a fixed bed reactor were continued. Additionally, as part of the effort to investigate niche market applications for KENTORT II-derived products, a study of the synthesis of carbon fibers from the heavy fraction of KENTORT II shale oil was initiated.
Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.
The objectives of this program are to evaluate the Coal Fired Combined Cycle (CFCC) power plant conceptual design and to conduct supporting development programs for pressurized fluidizedbed technology advancement in combustion/steam generator, gas turbine and hot gas cleanup technologies. The Coal-Fired Combined Cycle is the unique power plant concept developed under the leadership of the General Electric Company to provide a direct coal-burning gas turbine and steam turbine combined-cycle power plant. The advantages of the combined cycle for higher efficiency and the potential of the pressurized fluidizedbed combustor improvements in emissions could offer a new and attractive option to the electric utility industry. The CFCC approach provides for cooling the fluid bed combustor through the use of steam tubes in the bed which supply a steam turbine generator. ...
Tests with a 61 cm diameter fluidized-bed combustor revealed that raw cotton gin trash could be efficiently burned while satisfying Federal standards for particulate emissions. Certain chemicals within cotton gin trash zone can cause slagging or caking of ash and bed particles in the combustion zone. They can also corrode and accumulate on the heat recovery equipment. These problems are not considered insurmountable and methods of control are being studied. Raw cotton gin trash was also converted into a low Btu gas using fluidized-bed technology. Tests with a 30 cm diameter gasifier revealed that raw gin trash could be converted to a combustible gas, containing carbon monoxide and hydrogen. The heating value of the gas ranged from 3.65 to 5.29 MJ/m3 and about 50 percent of the heat value of the raw trash was converted to combustible gases. Economic analyses have shown that these techniques can be economically competitive ...
This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidizedbed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is correctly predicted by the model. The predictions are better at higher ...
The paper gives an overview on the technologies and applications of automatic wood furnaces. The combustion systems are defined by the flow condition: With increasing gas velocity, fixed bed, stationary fluidizedbed (SFB), circulating fluidizedbed (CFB), and entrained flow reactors are distinguished. The furnace design and typical applications are described. Further, a comparison is presented which gives data of the typical size range and fuel types for the different combustion systems. The most common fixed bed reactors are under-stoker and grate furnaces. While under-stoker furnaces are applied in the size range from 20 kW to 2.5 MW, grate furnaces cover the size range from a few 100 kW up to more than 50 MW. Under-stoker furnaces are well suited for wood fuel with low ash content, moderate water content and limited fuel size. Grate furnaces are also suited ...
A process and apparatus for the production of coke, asphalt and jet fuel m a feed of fossil fuels containing volatile carbon compounds therein is disclosed. The process includes the steps of pyrolyzing the feed in an entrained bed pyrolyzing means, separating the volatile pyrolysis products from the solid pyrolysis products removing at least one coke from the solid pyrolysis products, fractionating the volatile pyrolysis products to produce an overhead stream and a bottom stream which is useful as asphalt for road pavement, condensing the overhead stream to produce a condensed liquid fraction and a noncondensable, gaseous fraction, and removing water from the condensed liquid fraction to produce a jet fuel-containing product. The disclosed apparatus is useful for practicing the foregoing process. the process provides a useful method of mass producing and jet fuels from materials such as coal, oil shale ...
The physical structure of a limestone or dolomite to be used in in-bed sulfur capture in fluidizedbed boilers has great impact on the efficiency of sulfur capture and sorbent use. Therefore in process optimization and model calculations parameters describing the pore structure of these sorbents must be included. In this study an unreacted shrinking core model with variable effective diffusivity is applied to sulfation test data from a pressurized thermogravimetric apparatus (P-TGA) for various limestone and dolomite samples. The particle size was 250--300 {micro}m for all sorbents. The tests were done under typical conditions for a pressurized fluidizedbed combustor, i.e. 850 C or 950 C, 15 bar, and were reported earlier at the 12th International Conference on FluidizedBed Combustion. At these conditions the limestone remains uncalcined, ...
The main purposes of this research was to investigate the feasibility of incineration of wool-scouring sludge in a novel vertical-axis-rotating fluidised bed (RFB). The experiment was carried out in a RFB with an internal diameter (ID) of 200 mm and height of 50 mm. A cold test was first conducted to investigate the fluidization performance of the RFB via parameters such as the bubbling, gas distribution, bed shape and pressure drop. The tumbling phenomena was observed in the bed, and this effectively enhanced the axial mixing. The appropriate range of bed thickness, rotating speed and sand particle size were identified to ensure the full fluidization and reduce the particle elutriation. Four wool-scouring sludges from different processes were incinerated in the RFB. With 5% support methane, all sludges with a maximum moisture up to 70% as received could be ...
In the research of a more efficient, less costly, more environmentally responsible and less technically difficult method for generating electrical power from coal, `the Partially Gasified Coal Fired Combined Cycle with a CFBC with Different Speeds (DFBC)` is introduced by Tsinghua University. The high efficiency cycle includes gasification, compressed air heating in a fluidizedbed immersed air heater followed by a combustor and the heat recovery of gas turbine exhausted gas used as the combustion of coal in the differential-velocity atmospheric circulating fluidizedbed. Superheated steam is raised in the DFBC boiler. A preliminary analysis is made for the choice of combined cycle components. The computer program can be used to evaluate the design and off-design performance of the power plant. The simulation results show that the new system is a valuable coal fired combined cycle system for China, ...
Universal Oil Products, Inc. (UOP) of Des Plaines, Illinois has contracted A.E. Roberts & Associates, Inc. (AERA) of Atlanta, Georgia to prepare a sensitivity analysis for the development of the Fluidized-bed Copper Oxide (FBCO) process. As proposed by AERA in September 1991, development of the FBCO process design for a 500 mega-watt (MW) unit was divided into three tasks: (1) Establishment of a Conceptual Design, (2) Conceptual Design, (3) Cost Analysis Task 1 determined the basis for a conceptual design for the 500 megawatt (MW) FBCO process. It was completed by AERA in September of 1992, and a report was submitted at that time {open_quotes}Establishment of the Design Basis for Application to a 500 MW Coal-fired Facility.{close_quotes} Task 2 gathered all pertinent data available to date and reviewed its applicability to the 500 MW FBCO process. Work on this task was carried out on a joint basis by the AERA team members: Roberts & Schaefers worked on the ...
Candidate materials for components of a fluidized-bed waste heat recovery system (FBWHRS) include plain carbon steel, types 405 and 316 stainless steel, and alloy 800. These materials were exposed to synthetic flue gas at anticipated FBWHRS temperatures and higher for 3000 h to determine corrosion rates. The synthetic flue gas was a combustion atmosphere to which Cl/sub 2/ and HCl were added. The projected annual corrosion rate for plain carbon steel is about 0.08 mm/year (0.003 in./year) at 250 to 290/sup 0/C, but it would exceed 0.5 mm/year (0.02 in./year) at 560/sup 0/C. The projected annual corrosion rates of the other materials were less than 0.25 mm/year (0.01 in./year) at the maximum test temperatures of 560, 660, and 665/sup 0/C for type 405, type 316, and alloy 800, respectively. These results indicate that corrosion of candidate FBWHRS materials will not be significant at anticipated operating temperatures for various components unless other factors, not ...
Factors important in choosing between process concepts were mechanical complexity and amenability to scale-up studies. The culmination of this work was a process concept known as Staged Turbulent Bed Retorting Process (STB), which has now been tested in pilot plants. Operating conditions are described. The environment in the retort section can be described as a staged, moving bed of particles, in which a portion of the particles are fluidized at gas velocities well below minimum fluidization velocity of many of the particles. Research and engineering evaluations have established that the STB provides prospects for the responsible development of oil shale resources on a commercial scale. A 320 ton/d semiworks unit, the next technological step, will be commissioned shortly. This unit will be large enough to provide scale-up data for design of modules and to demonstrate the entire process, generating data ...
Devolatilization, char combustion and emission characteristics of different single fuel particles were studied under various fluidizedbed combustor conditions, in order to develop a classification system which enables prediction of the behaviour of different fuels ranging from fixed carbon rich coals to volatile rich woods and plastics. To investigate formation reaction, the concentration of CO, CO{sub 2}, total hydrocarbons, O{sub 2}, NO and N{sub 2}O were measured continuously. Additionally, temperature histories of the particles were recorded by implanting thermocouples. Devolatilization and char combustion were analysed by an integral and differential method. The integral analysis uses global rates which were compared with the ultimate and proximate analyses and used to classify the fuels. In the differential analysis the single physical and chemical steps viz mass transfer from the bulk gas to the particle surface, mass transfer through ...
Pyrolysis of Greek fir wood samples in a fluidizedbed reactor was studied. The experimental conditions selected control the yield of gaseous, liquid and solid products. The factors examined were: pyrolysis temperature, mean particle size, pressure, residence time of volatiles, lignin content of biomass and moisture content. The experiments were performed on the basis of a 12-run Plackett-Burman fractional factorial design. Statistical analysis of the data showed that the pyrolysis temperature is the main factor affecting the distribution of the yields of liquids, their phenolic fraction and gases in the range of experimental conditions tested. Empirical expressions were obtained from linear regression giving the yields of liquids, phenols and gases in terms of temperature. The maximum predicted yields were 56 and 12 wt.% on a moisture-free basis at 520 C and 545 C for liquids and phenols, respectively. The yield of gases increased ...
The magnetically fluidizedbed (MFB) was used as the reactor in a novel semidry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency. Experiments in a laboratory-scale apparatus were conducted to reveal the effects of approach to adiabatic saturation temperature, Ca/S molar ratio and applied magnetic field intensity on SO(2) removal. Results showed that SO(2) removal efficiency can be obviously enhanced by decreasing approach to adiabatic saturation temperature, increasing Ca/S molar ratio, or increasing applied magnetic field intensity. At a magnetic field intensity of 300Oe and a Ca/S molar ratio of 1.0, the desulfurization efficiency (excluding desulfurization efficiency in the fabric filter) was over 80%, while spent sorbent appeared in the form of dry powder. With the SEM, XRD and EDX research, it can be found that the increase of DC magnetic field intensity can make the surface morphology on the surface of the ...
The article profiles developments in pollution control resulting from the strict emissions control standards due to be set by the European Commission in 1992. In particular technology to meet new emissions targets for mercury and dioxins is described. Control technologies covered included fixed-bed, direct injection, circulating fluidizedbed and spray adsorption all of which use activated charcoal to absorb dioxin and mercury. Unfortunately activated charcoal processes still leave waste to be disposed of. Options include recycling the spent activated charcoal to the incinerator, vitrifying the activated charcoal and fly ash into a glassy unleachable substance and cracking the dioxins catalytically. It is hoped the developments will increase public acceptance of incineration. 4 figs., 1 tabs.
Pressurized fluidizedbed combustion (PFBC) is an emerging coal-fired, combined-cycle power generation technology nearing commercial status through several operating and planned demonstration plants throughout the world. Current-generation PFBC plants use ``ruggedized`` gas turbines that can tolerate dust loading common with conventional cyclone gas cleaning. The next generation of PFBC will apply advanced hot gas cleaning systems that will reuse the dust loading to low levels acceptable to high performance, industrial gas turbines. These advances should result in performance and cost advantages. This article examines the demonstration of PFBC technology at Tidd power station.
The integration of a gas turbine into a new type of coal-fired combined cycle power plant necessitates a multiplicity of far-reaching changes compared with a normal design. The extremely high pre-heating temperature of the air emanating from the heat exchanger of the fluidizedbed for the gas turbine combustion chamber has necessitated extensive development work and associated combustion trials. It was possible for these results to influence the design of the burners whereas the manufacture of other components which was on the critical path was already far advanced.
This article describes innovations in new-boiler startups, based on experiences at United Development Group`s 50-MW Niagra cogeneration facility, Niagra Falls, NY. The plant comprises: a circulating coal fluidizedbed boiler supplying steam to a nearby factory and electricity to the grid. Before operation the system was flushed with demineralized water, and the boiler degreased, the steam blow relied on a new procedure involving a continuous flow of steam. Startup was then initiated, following manufacturers heatup rate and soak times closely. After startup boiler tube sections were checked, and cleaned if necessary. 1 fig.
Visualizations by real-time neutron radiography are demonstrated of various flow patterns of nitrogen gas-water two-phase flow in a stainless-steel tube, water inverted annular flow in a stainless-steel tube, flashing flow in an aluminium nozzle and fluidizedbed in aluminium tube and vessels. Photographs every 1/60 s are presented by an image processing method to show the dynamic behaviours of the various flow patterns. It is shown that this visualization method can be applied efficiently to multiphase flow researches and will be applicable to multiphase flows in industrial machines. (author).
Visualizations by real-time neutron radiography are demonstrated of various flow patterns of nitrogen gas-water two-phase flow in a stainless-steel tube, water inverted annular flow in a stainless-steel tube, flashing flow in an aluminium nozzle and fluidizedbed in aluminium tube and vessels. Photographs every 1/60 s are presented by an image processing method to show the dynamic behaviours of the various flow patterns. It is shown that this visualization method can be applied efficiently to multiphase flow researches and will be applicable to multiphase flows in industrial machines. (author).
The concept of using agricultural residues, especially cotton gin trash (CGT), as a fuel for a small cogeneration power plant based on fluidizedbed gasification (FBG) requires that three problems be solved: (1) ash must be removed from the low calorific value (LCV) gas prior to combustion; (2) the high NO/sub x/ emissions associated with many biomass fuels must be significantly reduced; (3) a systems analyses of engineering/economic feasibility for potential applications must be developed. This paper addresses current research at TAMU pertaining to these problems.
The presented paper describes the formulation of the fractional mass balances which are used to calculate the concentration and size distribution of char in the balance cells of a circulating fluidizedbed boiler. In case of using the shrinking core model additionally the distribution of conversion of the char particles is calculated. Basically two reaction models (a shrinking particle and a shrinking core model) are available to describe the combustion process. The model considers all essential physico/chemical phenomena (primary fragmentation, attrition, mass transfer to gas phase) which have to be taken into account for the description of the combustion process. The model is part of an overall simulation program for circulating fluidizedbed boilers. This engineering simulator has been developed to return the main performance parameters of such systems like temperature along the furnace height, size ...
Initially, the decision of the operator in Dortmund-Derne to select the impact-type separator concept is explained. None of the tenderers for this 52 t/h boiler could supply references for this fluidizedbed steam generator concept with staged combustion in a high-expansion fluidizedbed. Under the circumstances, the simple configuration of the Steinmueller fluidizedbed steam generator, its compact construction, the reduced amount of refractory and the operational behaviour of the boiler resulting therefrom were decisive in the operator`s decision to select this concept. The development schedule shows the individual stages from cold and hot trials in various test rigs and pilot plants to the final design. So far, this fluidizedbed steam generator concept has been realized in the plants Derne (52 t/h), commissioned in ...
Chemical looping combustion is a novel technology that can be used to meet the demand on energy production without CO{sub 2} emission. To improve CO{sub 2} capture efficiency in the process of chemical looping combustion of coal, a prototype configuration for chemical looping combustion of coal is made in this study. It comprises a fast fluidizedbed as an air reactor, a cyclone, a spout-fluid bed as a fuel reactor and a loop-seal. The loop-seal connects the spout-fluid bed with the fast fluidizedbed and is fluidized by steam to prevent the contamination of the flue gas between the two reactors. The performance of chemical looping combustion of coal is experimentally investigated with a NiO/Al{sub 2}O{sub 3} oxygen carrier in a 1 kW{sub th} prototype. The experimental results show that the configuration can minimize the amount of residual ...
The feasibility of using three different solid fuels in chemical-looping combustion (CLC) has been investigated using NiO as oxygen carrier. A laboratory fluidized-bed reactor system for solid fuel was used, simulating a chemical-looping combustion system by exposing the sample to alternating reducing and oxidizing conditions. In each reducing phase 0.2g of fuel was added to the reactor containing 20g oxygen carrier. The experiments were performed at 970{sup o}C. Compared to previously published results with other oxygen carriers the reactivity of the used Ni-particles was considerably lower for the high-sulphur fuel and higher for the low-sulphur fuel. Much more unconverted CO was released and the fuel conversion was much slower for high-sulphur fuel such as petroleum coke, suggesting that the nickel-based oxygen carrier was deactivated by the presence of sulphur. The NiO particles also showed good reactivity with methane and a syngas mixture of 50% H{sub 2} and ...
Studies are made on coal in terms of its effective utilization, coal cleaning, fluidization and production of new fuel, and issues globally raised. Coal is abundant in reserves and high in supply stability and economic efficiency. However, it is much in CO2 emission per calorific value. To control as much CO2 emission as possible, effective utilization such as increasing of power generation efficiency has been proceeded with. In addition to ultra supercritical pressure and fluidizedbed combustion, cited are coal gasification combined cycle power generation and high temperature type fuel cell. Coal has 5-20% ash and impurities like sulfur/nitrogen. Coal should be used clean by pollution abatement measures such as dust collecting, desulfurization and denitrification. Japan is at a world top level of these technologies. Coal is solid, and therefore, is more difficult to handle than liquid fuel. To use it easily, coal is ...
The effect of combustion conditions on conversion of char nitrogen to N2 was studied in the combustion experiment of char obtained by pyrolysis of coal. Char specimen was prepared by holding ZN coal of Chinese lignite in Ar atmosphere at 1123K for one hour. A batch scale quartz-made fluidizedbed reactor was used for combustion experiment. After the specimen was fluidized in reaction gas, it was rapidly heated to start combustion reaction. CO, CO2 and N2 in produced gases were online measured by gas chromatography (GC). As the experimental result, under the incomplete combustion condition where a large amount of CO was produced by consuming almost all of O2, no NOx and N2O produced from char were found, and almost all of N-containing gas was N2. At the final stage of combustion, pyridinic-N disappeared completely, and pyrrolic-N decreased, while O-containing nitrogen complexes became a main component. It was thus suggested ...
This paper reports that there are four combustion technologies upon which U.S. electric utilities are expected to rely for the majority of their future power generating needs. These technologies are pulverized coal- fired combustion (PC); coal-fired fluidizedbed combustion (AFBC); coal gasification, combined cycle systems (CGCC); and natural gas-fired combined cycle systems (NGCC). The engineering and economic parameters which affect the choice of a technology include capital costs, operating and maintenance costs, fuel costs, construction schedule, process risk, environmental and site impacts, fuel efficiency and flexibility, plant availability, capacity factors, timing of startup, and the importance of utility economic and financial factors.
In the past shredder fluff from automobile recycling was discarded in landfills, but shrinking landfill space and the partly hazardous content of the fluff as well as its caloric value, all resulted in efforts to turn this waste problem into an energy resource. In order to produce a fuel, the inorganic compounds have to be removed. Extensive analyses and particle size measurements were made on fluff from various shredder. For optimal separation all particles are reduced to a uniform, relatively small size. In a subsequent combined screening and air classification process, successful separation into organic and inorganic fractions is achieved. The inorganic fraction is treated in a heavy media or an eddy-current separator to recover the valuable metals, while the organic fraction is now suitable for thermal processing, such as fluidizedbed gasification and using the resulting carbon as a chemical reagent.
Single-particle combustion of coal char is analyzed using a generalized shrinking core model. Finite volume method, which was earlier employed by the authors in solving moving boundary problems involving fluid-solid noncatalytic reactions in general, is used to solve fully transient mass and energy equations. The model takes into account convection and diffusion inside the particle as well as in the boundary layer. The computed results are compared with the experimental data of the authors for combustion of coal char in a fluidizedbed combustor. The effects of parameters such as bulk temperature and initial particle radius on the combustion dynamics are examined. The phenomena of ignition and extinction are also investigated. Finally, the importance of Stefan flow, originating due to nonequimolar counterdiffusion, on combustion of coal char is analyzed.
Abstracts are presented for about 40 papers. The Fossil Energy Advanced Research and Technology Development Materials program is an integrated materials research activity of the fossil energy coal program, whose objective is to conduct R and D for all advanced coal conversion and utilization technologies. The program is aimed at understanding materials behavior in coal system environments and the development of new materials for improving plant operations and reliability. A generic approach is used for addressing multiple coal technologies; for example, the hot-gas particulate filter development is applicable to pressurized fluidizedbed combustion, integrated coal gasification combined-cycle, coal combustion, and indirectly fired combined-cycle systems.
Since fuel oil meeting the requirements of current petroleum products can be produced by SASOL F-T synthetic process, the manufacturing process of hydrocarbon fuel oil from the coal-derived synthesis gas, downstream processes are being successively investigated. Mobile M-gasoline, MTG, process which produces gasoline from the natural gas-derived synthesis gas through methanol went into commercial operation in New Zealand in 1986. Although the gasoline suffices the quality of commercial gasoline by both fixed bed and fluidizedbed systems, the price and service life of catalyst and control of by-product durene must be improved. Any STG processes have not been completed yet and the yield and quality of gasoline are inferior to those of gasoline produced by the MTG process. Applying two-stage process, the STG process will be more economically effective.(21 refs, 4 figs, 10 tabs)
Wastewater from a food-manufacturing plant with a low concentration of organic matter was treated at 37 centigrade in an anaerobic fluidized-bed reactor or in an upflow anaerobic sludge blanket. As the influent TOC (total organic carbon) concentration decreased, the TOC removal efficiency in these reactors decreased from 85% to 65%. The concentration of suspended solids in the effluent could be reduced to 20 mg/l, which corresponded to 7% of that in the influent. The effluent from both reactors was treated aerobically in a fixed-bed reactor. The TOC concentration and optical density of effluent from the aerobic treatment were reduced to 5 mg/l and 0.005, respectively. When the effluent treated anaerobically or aerobically was passed over an activated carbon column, the effluent TOC concentration was reduced to 2 to 3 mg/l. The conductivity in raw wastewater was remarkably reduced on an ion-exchange resin column. Ultra-pure water for industrial ...
As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBRS) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. ...
In China, the conventional utilization of oil shale is concentrated mainly on oil shale retorting, and burning oil shale in pulverized furnaces, or bubbling fluidizedbeds. To improve the availability of oil shale, many specialists have advocated burning oil shale in a circulating fluidizedbed (CFB), which has a satisfactory combustion efficiency, low NOx and SO{sub 2} emission, adaptability to low-grade coal, etc. In Huadian, China, a plant incorporating three units of 65 th{sup -1} oil shale-fired CFB began successful commercial operation in 1996, proving that burning oil shale in a CFB produces both high combustion efficiency and environmental protection. For effective utilization of oil shale, its pyrolysis and combustion characteristics, emission performance of gaseous pollutants from an oil shale-fired CFB pilot setup, co-combustion characteristics of oil shale and high sulfur coal as well as the ...
The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the multi-year program, initiated in October 1987 by the US Department of Energy is to perform the research necessary to develop the Pressurized Fluidized-Bed Hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The results of the original 3-year program, which was concluded in May 1991, have been summarized in a four-volume final report published by IGT. DOE subsequently approved a 1-year extension to the program to further develop the PFH process specifically for application to beneficiated shale as feedstock. Studies have shown that ...
The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the multi-year program, initiated in October 1987 by the US Department of Energy is to perform the research necessary to develop the Pressurized Fluidized-Bed Hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The results of the original 3-year program, which was concluded in May 1991, have been summarized in a four-volume final report published by IGT. DOE subsequently approved a 1-year extension to the program to further develop the PFH process specifically for application to beneficiated shale as feedstock. Studies have shown that ...
This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidizedbed and in the process indentifying the parameters that affect the ...
A joint materials test program developed by the Institute for Mining and Minerals Research (IMMR) and the Tennessee Valley Authority (TVA) involved the postexposure mechanical properties and corrosion behavior of candidate structural materials in an experimental, atmospheric fluidized-bed combustor (AFBC). This combustor was operated by Accurex Corporation at Research Triangle Park, North Carolina, under the direction of TVA. The materials studied were Type 304, Type 310, and INCOLOY alloy 800 in the form of disc coupons with and without crevice configurations. Type 304 was also used for mechanical property measurements. The alloys were exposed to the combustor environment at about840/sup 0/C for approximately 330 hours. The ranking in terms of decreasing weight loss was: (1) Type 304, (2) Type 310, and (3) INCOLOY alloy 800. The presence of tight crevices did not enhance the corrosion rate. In addition, the corrosion rates, based on the weight loss (typically 1 to ...
The object of this survey of small US electric utility systems was to determine the potential utilization of small, fuel-flexible, advanced-cycle combustion turbines for power generation. Three prototype concepts were evaluated. Concept A: a 2.5 MWe externally fired, closed-cycle combustion turbine, with fluidized-bed combustor, burning solid fuels. Concept B: an open 3.8 MWe, indirect-fired, combined-cycle turbine system using solid, liquid or gaseous fuels, with downstream stack cleanup. Concept C: 11.6 MWe, utilizing an open, direct-fired, combined-cycle turbine arrangement, gas or oil fueled employing components of advanced development. It was presumed such units might be commercially available circa 1985 to 1990. Fifty-three utilities, encompassing a variety of ownerships, geographical distribution and system sizes, were interviewed on-site. Questions covered the probable use of such generating concepts and their perceived attributes. The report presents the ...
In Uganda, biomass comprises more than 95 per cent of the total energy supply. Agricultural residues are a major source of energy that can be converted into producer gas in biomass gasifiers. The high poverty levels in Uganda can be attributed in part to the fact that more than 90 per cent of the population does not have access to electricity due to limited and unreliable electricity produced in the country. A circulating fluidizedbed (CFB) gasification system was designed in this study in order to generate a system for the effective use of agricultural wastes for energy production. Rice husks were used as the feedstock for a power output of 60 MW. The gasification system was designed using ERGUN CFB software with available theoretical and experimental data. The design comprises a reactor subsystem, air distribution plate, cyclone, air inlet and fuel feeding systems. The reactor is 10 m high and has a fuel flow rate of 8.1 kg/s. The inlet air ...
The objective of this project is to develop a pellet formulation which is capable of achieving low sulfur partial pressures and a high capacity for sulfur, loaded from a hot fuel gas and which is readily regenerable. Furthermore the pellet must be strong for potential use in a fluidizedbed and regenerable over many cycles of loading and regeneration. Regeneration should be in air or oxygen-depleted air to produce a high-concentration sulfur dioxide. Fixed-bed tests were conducted with several formulations of manganese sesquioxide and titania, and alumina They were subject to a simplified fuel gas of the oxygen-blown Shell type spiked with a 30,000ppmv concentration of H{sub 2}S. Pellet crush strengths for 4 and 2mm diameter pellets was typically 12 lbs per pellet and 4 lbs per pellet, respectively. For the most favorable of the formulations tested and under the criteria of break-through at less than 100ppmv H2S and loading ...
When biomass is used as fuel for thermal conversion plants, minerals from the fuel can be responsible for major problems. Generally, these problems are associated with the existence and development of low melting compounds or eutectics, which form sticky layers. In a fluidised bed, this can result in bed-agglomeration and defluidisation. This causes local high temperature, which often accelerates the process. It ultimately can lead to a completely sintered bed content with a glassy phase gluing the bed particles together and shut-down of the plant. The main objective of the title project is to develop a methodology to predict ash/bed agglomeration and sintering problems, to indicate related problems and, furthermore, to identify solution methods to make different types of biomass streams more viable for energy production. Within the present study, selected fuels are subjected to ...
Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be ...
Co-combustion tests for recycled fuels and peat were made at a 15 kW fluidizedbed reactor at VTT Energy in Jyvaeskylae. Peat was used as reference fuel. 25 tests in total were performed during 1994 - 1996. A part of the peat energy was substituted by coal in five tests, in order to change the sulphur/chlorine ratio of the fuel mixture. Fuel mixtures (25% recycled fuel and 75% peat, at energy ratio) were pelletized in order to get homogeneous fuel mixtures. The tests in the year 1994 were air staging experiments (with and without tertiary air). All test were performed with air staging in the years 1995 and 1996. The aim of the research was to determine whether the co-combustion of waste materials will cause additional emission problems, as compared to combustible emissions from conventional air-staged fluidizedbed combustion. Further, the aim was to study which large-volume components can be burned ...
This study follows previous experimental work showing that the shrinking-core model applies to the pyrolysis (i.e., heating in the absence of oxygen) of particles (diam.{approx}14 mm) of a bituminous coal or a lignite in a fluidizedbed at 700-950 {sup o}C. These experimental facts are in accord with the production of volatile matter being endothermic and not thermoneutral, as often assumed. Also, the rate at which volatile matter is produced in the presence of oxygen (i.e., devolatilization) or in its absence (pyrolysis) is demonstrated here to be controlled not at all by mass transfer, but by heat conduction to a moving reaction front inside a coal particle, provided its diameter exceeds {approx}3 mm. The resulting steady-state model of devolatilization indicates that six dimensionless groups are required to describe the rate of(I)coal->char+volatile matter for a nonfragmenting and nonswelling coal. This reaction occurs for a total ...
Concerning the transient phenomenon of solid-gas two-phase flow, an attempt was made to visualize and measure a flow phenomenon in which three-dimensional bubbles occurred, grew and collapsed in the vicinity of a gas injection nozzle while solid particles were circulating. Such a phenomenon could not or hardly be visualized and measured by conventional methods. Such two-phase flow was visualized using neutron radiography, its characteristics measured and the usefulness of the visualization by neutron radiography confirmed. For this purpose, three-dimensional fluidizedbed vessels, rectangular or cylindrical-shaped, made of steel or aluminum sheet, were prepared. Polyethylene or glass beads were used as solid particles and activated carbon particles as the tracer. In the experiment, nitrogen gas was blown into the vessel from one nozzle and distributors provided at the bottom of the vessel and exhausted from the top via the exhaust valve, by ...
TSS (thermal swing sublimation) method was studied which uses vaporization heat and sensible heat of LNG for solidification and separation of CO2 gas in waste gases of LNG-fired combined cycle power generation system. In experiment, the mixed gas composed of CO2, H2O and N2 was used for simulating waste gas of LNG-fired combined cycle power generation systems, and the growth behavior of ice and dry ice was studied for developing dry ice making technology under low-temperature condition. As the experimental result, the following were clarified: various crystal structures depending on cooling temperature, the effect of gas flow rate on peeling of surface precipitated solids, and solidification characteristics of H2O/CO2 mixed gas. The growth rate of precipitated solid film thickness decreased with an increase in gas flow rate, while increased with CO2 concentration. The shape of a dry ice sublimator similar to that of a fluidizedbed heat ...
In the context of the research project, the physical basis of the direct decoupling of highly concentrated solar radiation in materials without the detour via absorbing heat exchanger walls was examined. Also, the first chemical processes suitable for the effective long-term storage of solar energy were analysed, relevant experiments were carried out and the necessary receiver techniques for high temperature applications were provided. The principle of direct coupling was examined on fluidizedbeds on the one hand and on cavity receivers, on the other hand. The contribution shows the results achieved in detail. It is recorded that first processes for storing solar energy in chemical reactions were able to be examined. Alkaline earth hydroxides accommodated in ceramic honeycomb structures seem to be possible as stores for medium temperature ranges around 500deg C. Investigations on receiver structure materials are also making progress. Highly ...
The goal of this work was to develop a process flow diagram to economically produce a clean-burning fuel from fine Illinois coal. To accomplish this, the process of pelletizing fine coal with calcium hydroxide, a sulfur capturing sorbent, was investigated. Carbonation, which is the reaction of calcium hydroxide with carbon dioxide (in the presence of moisture) to produce a bonding matrix of calcium carbonate, was investigated as a method for improving pellet quality and reducing binder costs. Proper moisture level is critical to allow the reaction to occur. If too much moisture is present in a pellet, the pore spaces are filled and carbon dioxide must diffuse through the water to reach the calcium hydroxide and react. This severely slows or stops the reaction. The ideal situation is when there is just enough moisture to coat the calcium hydroxide allowing for the reaction to proceed. The process has been successfully demonstrated on a pilot-scale as a method of hardening iron ore ...
To address the need for integrated models of advanced power generation systems and for improved analysis techniques, the US Department of Energy (DOE), through the Morgantown Energy Technology Center (METC), has supported the development of performance, emissions, and cost models of several advanced power generation systems, including integrated gasification combined cycle (IGCC), externally-fired combined cycle (EFCC) and pressurized fluidizedbed combustion (PFBC) concepts. Simultaneously, numerical methods for simulation of uncertainties and optimization of process flowsheets have been implemented in the DOE`s public version of ASPEN. The new process models and computational capabilities have been applied to demonstrate the benefits of quantitative approaches to dealing with uncertainty and for optimizing technologies in the face of uncertainty. This paper focuses on modeling and assessment of the EFCC system concept. The purpose of the ...
Excessive use of poultry litter (PL) on agricultural land is known to cause eutrophication of surface waters. Consequently, both poultry producers and PL users have to meet strict state and federal guidelines on litter storage and land application. This study examined the environmental benefits of adding lime, alum, ferrous sulfate, fly ash (FA), fluidizedbed ash (FBA) and soil fix (SF) to PL for immobilizing excess phosphorus (P) while providing sufficient nutrients for proper growth of soybean [Glycine max (L.)] and corn [Zea mays (L.)] on a rotation. Amending PL with lime, alum, SF, FA and FBA significantly (p>0.05) increased corn and soybean yield. In contrast control plots that received a 10-10-10 (N-P2O5-K2) fertilizer showed lower yield and corn quality. Increased yield was ob...
In China, the conventional utilization of oil shale is concentrated mainly on retorting oil shale to produce shale oil and fuel gas, and burning oil shale to generate electricity. The growth of petroleum price, and the development in heavy industry, make these conventional utilization facilities become unavailable on the energy market. In this paper, a new comprehensive utilization system is recommended for the future use of Huadian oil shale, based on the current status of energy and the characteristics of oil shale. The system involves three subsystems: retort subsystem, where coarse oil shale (8-80 mm) is retorted to shale oil, hydrocarbon gases and oil shale semicoke; combustion subsystem, where the mixture fuel of oil-shale semicoke and fine oil shale (0-8 mm) is fed to a circulating fluidizedbed (CFB) furnace to burn, in order to generate high-pressure steam which is used to supply heat and generate electricity via a traditional ...
Advanced coal-fired combined-cycle power systems under development and demonstration have the potential to increase generating efficiency to approach 50%, reduce the cost of electricity by up to 20%, and meet stringent standards on emissions of SO{sub x}, NO{sub x}, fine particulates, and air toxic metals. Integrated gasification combined cycle, pressurized fluidized-bed combustion, and externally fired combined cycle systems rely on different high-temperature combinations of heat exchange, gas filtration, and sulfur capture to meet these requirements. The success of these systems when operated on low-rank coals depends importantly on the behavior of the ash. This paper focuses on the behavior of ash in an intermediate-scale transport gasifier coupled with a hot-gas cleanup system. The work reported is part of the overall program on hot-gas cleanup and the transport reactor development unit (TRDU) located at the Energy and Environmental Research Center (EERC), ...
Under typical conditions found in Pressurized FluidizedBed Combustion (PFBC), the calcination reaction of limestones is thermodynamically inhibited, and the sorbent reacts with SO{sub 2} by a direct mechanism. Direct sulfation reactivity of different Spanish sorbents was studied by high-pressure thermogravimetric analysis. It was found that the physical structure of the surface of the particles influence the sulfation behaviour of the sorbents. Total pore volume and pore surface area correlated well with the reactivity of the sorbents. Temperatures between 800 and 925{degree}C, and pressure between 12 and 25 bar, promoted an increase in reactivity, while the gas composition had no effect when changed from 15% CO{sub 2}, 3% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2} to 12% CO{sub 2}, 7% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2}. It was found that the unreacted shrinking core model could not satisfactorily describe the sulfation reaction under ...
In the wide range from brown coal to anthracite, an investigation was made of effects of heat treatment on physical/chemical properties and of coal rank dependence. For the experiment, 12 kinds of coal samples were used, and for heat treatment, the fluidizedbed heated by the electric furnace and the infrared-ray gold image furnace were used. To examine characteristics of the heat-treated coal char, conducted were oxygen gasification, TPD measurement, XRD measurement, alkali metal measurement, and pore distribution measurement. The following were obtained from the experiment. The gasification reaction rate of the char heat-treated in the temperature range between 900{degree}C to 1700{degree}C decreases with a rise of the temperature of heat treatment, and the degree of decrease in the rate depends on coal rank. The order of gasification rate between coal ranks depends on the temperature of heat treatment, and the lower the heat treatment ...
Liquid radioactive raffinates from nuclear fuel reprocessing at the Idaho National Engineering and Environmental Laboratory were solidified, or calcines, in a fluidizedbed reactor at approximately 500 C to form a dry granular material. This calcine has been provisionally stored near-surface in concrete-encased stainless steel bins at the Idaho Nuclear Technology Engineering Center. Research addressing the permanent immobilization of radioactive waste has been ongoing. One option is to separate the radioactive constituents from the calcine, thereby reducing the radioactive waste volume to be ultimately stored at a national nuclear waste repository. Nitric acid dissolution of the calcine is a key front-end unit operation in the separations option. In order to design calcine dissolution equipment, quantification of dissolution reaction rate parameters is required. A pilot-plant-produced, non-radioactive calcine was utilized to study the ...
The present paper deals with the fouling process of calcium sulfate dehydrate on heat-transfer surfaces. The crystallization of calcium sulfate showed typical asymptotic fouling curves, the asymptotic value of which was greatly influenced by the surface temperature and fluid velocity. The fouling mechanism was discussed with a generalized fouling model and proved to be surface process controlled, where the activation energy was 6.2 {times} 10{sup 4} J/mol. The availability of mechanical cleaning against the formed scale was quantitatively evaluated by applying the particle abrasion method. The removal test verified that the removing rate per unit particle concentration decreased in an inverse proportion to the overall particle load, to the power of 0.8, and that it was affected by the fluid velocity. The observed final residual fouling resistance decreased asymptotically with an increase in particle concentration. The suitable concentration of the abrasive particles for mild cleaning ...
Methods were studied for using sugar as a feed additive for converting the sodium-bearing wastes stored at the Idaho Chemical Processing Plant into granular, free flowing solids by fluidized-bed calcination at 500{degrees}C. All methods studied blended sodium-bearing wastes with Fluorinel wastes but differed in the types of sugar (sucrose or dextrose) that were added to the blend. The most promising sugar additive was determined to be sucrose, since it is converted more completely to inorganic carbon than is dextrose. The effect of the feed aluminum-to-alkali metal mole ratio on calcination of these blends with sugar was also investigated. Increasing the aluminum-to-alkali metal ratio from 0.6 to 1.0 decreased the calcine product-to-fines ratio from 3.0 to 1.0 and the attrition index from 80 to 15%. Further increasing the ratio to 1.25 had no effect.
Investigation of co-gasification of biomass-coal blends in oxygen-containing atmosphere was carried out in a pressurized fluidizedbed gasifier. Different biomass materials including wood and energy crop were used in the study, whereas the coal used was in bituminous rank from UK, The gasifier used was a Laboratory Development Unit (LDU) with an inner diameter of 144 mm. The operation temperature and pressure were varied in the investigation. The research was part of the European Union's Joule Ill clean coal technology programme. The study was focused on possible synergies in the thermochemical treatment of the fuel blends. The char formed was examined. The tar produced in the process was analyzed. The environmentally concerned nitrogen compounds emitted from the process were detected. Interesting synergies were observed in the experimental study. The blends of the fuels and their char formed in situ demonstrated unexpected high ...
A rapidly hydrated sorbent for moderate-temperature dry flue gas desulfurization was prepared by rapidly hydrating adhesive carrier particles and lime. The circulation ash from a circulating fluidizedbed boiler and chain boiler ash, both of which have rough surfaces with large specific surface areas and specific pore volumes, can improve the adhesion, abrasion resistance, and desulfurization characteristics of rapidly hydrated sorbent when used as the adhesive carrier particles. The adhesion ability of sorbent made from circulation ash is 67.4% higher than that of the existing rapidly hydrated sorbent made from fly ash, the abrasion ratio is 76.2% lower, and desulfurization ability is 14.1% higher. For sorbent made from chain boiler ash, the adhesion ability is increased by 74.7%, the desulfurization ability is increased by 30.3%, and abrasion ratio is decreased by 52.4%. The abrasion ratios of the sorbent made from circulation ash having ...
For IGCC, the primary investment is too high due to the demand of high gasification efficiency. For PFBCC, the thermal efficiency is too low due to the relatively low turbine inlet temperature and the hot working medium of the gas turbine is not easy to clean. A new scheme is proposed for coal fired combined cycle to overcome the main drawbacks of IGCC and PFBCC. The research targets are developing a new cycle construction of coal fired combined cycle to raise the efficiency and reduce the primary investment. Actually, the new scheme is a synthesis of some existing proposals. It adopts partial gasification to reduce the primary investment of the gasification equipment. The un-gasified surplus solid is then fed to a pressurized fluidizedbed boiler, but adopting Curtiss Wright type external combustion to lower the ash content in the working medium. The gas fuel from the partial gasifier is combusted in a top combustor to further increase the ...
Chemical-looping combustion is an indirect combustion technology with inherent separation of the greenhouse gas CO{sub 2}. The feasibility of using NiO as an oxygen carrier during chemical-looping combustion of coal has been investigated experimentally at 800-960{degree}C in the present work. The experiments were carried out in a fluidizedbed, where the steam acted as the gasification-fluidization medium. Coal gasification and the reaction of oxygen carrier with the water gas take place simultaneously in the reactor. The oxygen carrier particles exhibit high reactivity above 900{degree}C, and the dry basis concentration of CO{sub 2} in the exit gas of the reactor is nearly 95%. The flue gas composition as a function of the reactor temperature and cyclic reduction number is discussed. At 800-960{degree}C, the dry basis concentration of CO{sub 2} in the flue gas presents a monotonously increasing trend, whereas the dry basis ...
ALSTOM Power Inc.'s Power Plant Laboratories (ALSTOM) has teamed with the U.S. Department of Energy National Energy Technology Laboratory (DOE NETL), American Electric Company (AEP) and Parsons Energy and Chemical Group to conduct a comprehensive study evaluating coal fired steam power plants, known as Rankine Cycles, equipped with three different combustion systems: Pulverized Coal (PC), Circulating FluidizedBed (CFB), and Circulating Moving Bed (CMB{trademark}). Five steam cycles utilizing a wide range of steam conditions were used with these combustion systems. The motivation for this study was to establish through engineering analysis, the most cost-effective performance potential available through improvement in the Rankine Cycle steam conditions and combustion systems while at the same time ensuring that the most stringent emission performance based on CURC (Coal Utilization Research Council) 2010 targets ...
Full text: During JET operations, tritium contaminated waste is generated principally but not exclusively from 'intervention' work and from removing or replacing redundant items. It is essential for JET and for any future fusion plant to have available a route for managing each waste stream however large or small, both during operation and decommissioning of the plant. The long term outcome is to have for each tritiated waste stream from JET a route for its management leading to its eventual disposal or recycling (and thus to be available for similar waste streams which will be produced by ITER operations). Since several years SCK#centre dot#CEN has been developing techniques for the treatment of tritiated waste. Amongst them, technologies for water detritiation, for the treatment of tritiated organic liquids and for the decontamination of several types of solid tritiated waste. Our R and D focuses on the development of a ...
The Coal Fired Combined Cycle (CFCC) is the unique powerplant concept developed under the leadership of the General Electric Company to provide a direct coal-burning gas turbine and steam turbine combined cycle powerplant. On the basis of previous studies and confirming work under this contract, General Electric continues to believe that the CFCC approach offers important advantages over alternate approaches: higher powerplant efficiency in the combustor temperature range of interest; reduced combustor/steam generator corrosion potential, due to low fluid-bed tube temperature (as contrasted to the air in tube cycle); and increased gas turbine bucket life from improved material protection systems. The objective of this program is to evaluate the coal fired combined cycle powerplant conceptual design, and to conduct a supporting development program. The supporting development is required for evaluating the pressurized fluidized ...
Early in 1988 RWE decided to overhaul the power station at Goldenberg. This was necessary due to the age of the plant, the obligation to supply heat and process steam and recent amendments of environmental legislation. After analysing demands and needs one developed a plant concept with a 290 t/h and a 400 t/h steam generator. Due to lack of space the decision was made in favour of a circulating atmospheric fluidised bed combustion instead of steam generators with pulverised lignite combustion as these steam generators take up much more space due to the legally required desulphurisation plants for gaseous emissions. Apart from generating steam RWE wishes to gain experience with this combustion technology and test it for suitability and use in large-scale plant. (orig./KO) [Deutsch] Aufgrund des fortgeschrittenen Alters, der aktuellen Umweltschutzgesetzgebung sowie bestehender Versorgungsverpflichtungen fuer Waerme und Prozessdampf wurde Anfang 1988 von der RWE ...
... values and unless special precautions and equipment are used, it would be very difficult to service and maintain operational jet-fuel systems with ...
Due to the increasingly stricter regulations for deep reduction of fuel sulfur content, development of new deep desulfurization processes for liquid transport fuels has become one of the major challenges to the refining industry and to the production of hydrocarbon fuels for fuel cell applications. The sulfur compounds in the current transport fuels corresponding to the S level of 350-500 ppm account for only about 0.12-0.25 wt % of the fuel. The conventional hydrotreating approaches will need to increase catalyst bed volume at high-temperature and high-pressure conditions for treating 100 % of the whole fuel in order to convert the fuel mass of less than 0.25 wt %. In the present study, we are exploring a novel adsorption process for desulfurization at low temperatures, which can effectively reduce the sulfur content in gasoline, jet fuel and diesel fuel at low investment and operating cost to meet the needs for ultra-clean transportation ...
The most developed systems for the generation of electricity from coal are the Integrated coal Gasification Combined Cycle (IGCC) and the Pressurized FluidizedBed Combustion (PFBC) system. They both represent state-of-the-art technology and provide electric power at 41-46% LHV efficiency. However, the high level of complexity leads to lower reliability and higher costs. A simpler system, based on a coal-fired steam boiler integrated with a gas turbine, has been proposed. In such a plant, known as the externally fired combined cycle (EFCC), compressed air is heated indirectly in a heat exchanger located in the coal furnace. The hot air is then expanded in a turbine, and the exhaust is passed on to the coal furnace as preheated combustion air. Steam produced in the boiler generates additional power in a steam turbine. The exclusion of coal combustion products from the gas turbine avoids hot gas clean-up and turbine blade corrosion by coal ash. ...
Coal fired combined cycle power systems will be a sufficient way to increase the efficiency of coal combustion. However, combined cycle power systems require a reliable hot gas cleanup. Especially alkali metals, such as sodium and potassium, can lead to hot corrosion of the gas turbine blading if they condensate as sulphates. The actual work deals with the release and sorption of alkali metals in coal fired combined cycle power systems. The influence of coal composition, temperature and pressure on the release of alkali species in coal combustion was investigated and the relevant release mechanisms identified. Alumosilicate sorbents have been found that reduce the alkali concentration in the hot flue gas of the Circulating Pressurized FluidizedBed Combustion 2{sup nd} Generation (CPFBC 2{sup nd} Gen.) at 750 C to values sufficient for use in a gas turbine. Accordingly, alumosilicate sorbents working at 1400 C have been found for the ...
The first part of the conference dealt with environmental effects of using coal. Papers dealt with the use of fly ash in agriculture and its effect on plant growth; the effect of airborne emissions on fish and wildlife resources, on watersheds, and on airsheds; the effects of surface mining on the ecology; blast effects; and health hazards associated with coal. The session on policy studies addressed the issue of cost of synthetic fuels and discussed the state and federal pollution regulations on burning coal and waste disposal. The session on combustion presented papers on atmospheric and pressurized fluidized-bed combustion for industrial and utility boilers. It also included papers on MHD power plants, coal-oil and coal-water mixtures, emission characterization and control, and catalytic combustors. The design of gasification plants, reaction kinetics, specific heats of coals and chars, simultaneous production of liquid and gaseous fuels, and economics of fuel ...
The first part of the conference dealt with environmental effects of using coal. Papers dealt with the use of fly ash in agriculture and its effect on plant growth; the effect of airborne emissions on fish and wildlife resources, on watersheds, and on airsheds; the effects of surface mining on the ecology; blast effects; and health hazards associated with coal. The session on policy studies addressed the issue of cost of synthetic fuels and discussed the state and federal pollution regulations on burning coal and waste disposal. The session on combustion presented papers on atmospheric and pressurized fluidized-bed combustion for industrial and utility boilers. It also included papers on MHD power plants, coal-oil and coal-water mixtures, emission characterization and control, and catalytic combustors. The design of gasification plants, reaction kinetics, specific heats of coals and chars, simultaneous production of liquid and gaseous fuels, and economics of fuel ...
This report discusses Test Campaign TC07 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC07. Prior to TC07, the Transport Reactor was modified to allow operations as an oxygen-blown gasifier. Test Run TC07 was started on December 11, 2001, and the sand circulation tests (TC07A) were completed on December 14, 2001. The coal-feed tests (TC07B-D) were started on January 17, 2002 and completed on April 5, 2002. Due to operational difficulties with the reactor, the unit was taken offline several times. The reactor temperature was varied between ...
A novel continuous powder introduction microwave-induced plasma atomic emission spectrometry method (CPI-MIP-AES) has been developed for trace determination of metals in ground and tap water samples after preconcentration on activated carbon. The experimental setup consisted of integrated rectangular cavity TE_1_0_1 and vertically positioned plasma torch. The technical arrangement of the sample introduction system has been designed based on the fluidizedbed concept. The satisfactory signal stability required for sequential analysis was attained owing to the vertical plasma configuration, as well as the plasma gas flow rate compatibility with sample introduction flow rate. The elements of interest (Cd, Cu, Cr, Fe, Mn, Pb, Zn) were preconcentrated in a batch procedure at pH 8-8.5 after addition of activated carbon and then, after filtering and drying of the activated carbon suspension, introduced to the MIP by the CPI system. An enrichment ...
This thesis surveys the concepts of exergy and extends the exergy method of analysis from the standpoint of its applications to the power plant systems. After a brief historical review of exergy concepts, the general exergy equation is derived from the combined equation of First and Second Law, and it is shown that any special case of exergy equation is a simplified form of the general exergy equation. The mathematical method for the exergy analysis of a steady-state, steady-flow system, analogous to that of the First Law, is given. The exergy losses in a power plant are discussed. Then in order to examine these losses, the Second Law performance of major processes of combustion, compression, heat transfer, mixing and throttling have been analyzed analytically, and the exergy efficiencies are defined that accurately assess the thermodynamic performance of the corresponding processes. The methods for computation of exergy loss and exergy efficiency are given and simplified for practical ...
Processes for the hydrogenation of carbon monoxide have had commercial importance since about 1920, when the commercial production of methanol and higher alcohols on oxide catalysts began. Soon thereafter Fischer and Tropsch discovered that liquid hydrocarbons could be synthesized from carbon monoxide and hydrogen over Group VIII metal catalysts. Following extensive catalyst and process development efforts, this technology provided Germany with a source of liquid fuels during World War II. The period following the war saw an acceleration in research and development on the Fischer-Tropsch process, but the only commercial application that was to emerge was the SASOL process in the Union of South Africa. The oil crises of the 1970s have rekindled worldwide interest in indirect liquefaction technologies for the production of clean, high-quality motor fuels from coal. The development of more efficient coal gasification processes and the advent of molecular sieve catalysts that allow ...
One of the five projects selected for funding within the Clean Coal Technology Program is a project proposed by the Pennsylvania Electric Company (Penelec) of Johnstown, Pennsylvania. Penelec proposes to enter into a cooperative agreement with DOE to design, construct and operate a 600 ton-per-day, 66-megawatt (MWe), coal-fueled, externally-fired combined cycle (EFCC) electric power generation facility. The EFCC is an emerging technology with promise for operating highefficiency combined gas- and steam-turbine cycles on coal. The central feature of EFCC is its coupling of the gas turbine to an external, atmospheric-pressure, coal combustor via a hightemperature ceramic heat exchanger (CerHx{reg_sign}) developed by Hague International. The EFCC technology is attractive because, unlike competing combined cycles such as Integrated Gasification (IGCC) and Pressurized FluidizedBed Combustion (PFBC), it eliminates the need for a costly gas cleanup ...
The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries
High-resolution observations are presented of the 300-kpc jet in the giant radio galaxy NGC 6251. The width of the jet is resolved over most of its length, and the axis of the jet wiggles with an amplitude increasing linearly with distance from the nucleus. Polarization data are used to derive densities of cold matter in the jet and, from the argument that the jet must form the lobe in a time equal to the age of the lobe, the speed of the jet is estimated as c/20. The energetics of the jet are then dominated by the bulk flow along it of cold matter at a rate of 1 solar mass yr"-"1. The jet appears to be confined; the wiggle of its axis is probably due to oscillations of the direction of the collimator with a period of about 6 x 10"6 yr. (author).
This bibliography includes over 600 references (with abstracts) on all aspects of waterjet cutting and cleaning. The references are listed under the following chapter headings: fluid mechanics of jets; jet impact; equipment; jet cleaning; jet cutting; civil engineering; mining and tunnelling; precision cutting; underwater; safety; and bibliographies. Separate author and corporate source indexes are provided.
Approximately 62,000 lbs Fuel Load: 58,000 lbs. Type Fuel: JP4, JP5, JP8, JET A, JET A-1, JET B Standard Fuel Burn: 4500 - 6000 lbs/hr depending on altitude and airspeed Maximum...
An experimental investigation of heat transfer characteristics for various configurations of air jets impinging on the leading edge inner surface of a gas turbine blade wall is presented. Three configurations were investigated, namely a slot jet, a round ...
Preliminary experiments have been performed to investigate the effects of radiative cooling on plasma jets. Thin (3 um - 5 um) conical shells were irradiated with an intense laser, driving jets with velocities > 100 km/s. Through use of different target materials - aluminium, copper and gold - the degree of radiative losses was altered, and their importance for jet collimation investigated. A number of temporally resoved optical diagnostics was used, providing information about the jet evolution. Gold jets were seen to be narrower than those from copper targets, while aluminium targets produced the least collimated flows.
... TITLE (Include Security Classification) Sorption of Selected Volatile Organic Constituents of Jet Fuels and Solvents on Natural Sorbents from Gas ...
fuel obligation under the RFS2 program for the production or importation of conventional jet fuel, RINs can be generated for renewable jet fuel. Is that right? A: As described in...
of refined petroleum and energy traders have stopped sales of refined product to Iran. Jet fuel suppliers are now refusing to supply jet fuel to Iran Air at most destinations in...
The two-dimensional Eulerian hydrodynamic code 2DE, with the shock initiation of heterogeneous explosive burn model called Forest Fire, is used to model numerically the interaction of jets of steel, copper, tantalum, aluminum, and water with steel, water, and explosive targets. The calculated and experimental critical condition for propagating detonation may be described by the Held V/sup 2/d expression (jet velocity squared times the jet diameter). In PBX 9502, jets initiate an overdriven detonation smaller than the critical diameter, which either fails or enlarges to greater than the critical diameter while the overdriven detonation decays to the C-J state. In PBX 9404, the jet initiates a detonation that propagates only if it is maintained by the jet for an interval sufficient to establish a stable curved detonation front. The calculated penetration ...
The two-dimensional Eulerian hydrodynamic code 2DE with the shock initiation of heterogeneous explosive burn model called Forest Fire, is used to model numerically the interaction of jets of steel, copper, tantalum, aluminum, and water with steel, water, and explosive targets. The calculated and experimental critical condition for propagating detonation may be described by the Held V/sup 2/d expression (jet velocity squared times the jet diameter). In PBX 9502, jets initiate an overdriven detonation smaller than the critical diameter, which either fails or enlarges to greater than the critical diameter while the overdriven detonation decays to the C-J state. In PBX 9404, the jet initiates a detonation that propagates only if it is maintained by the jet for an interval sufficient to establish a stable curved detonation front. The calculated penetration velocities ...
Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this...Full Text Available
Carbon capture and storage have been receiving increasing interest lately, mainly as an option to reduce CO{sub 2} emissions from the power sector. The concept could be adapted for production of H{sub 2} as well, which would provide a carbon free energy carrier that could be used for example as transportation fuel. In this doctoral thesis, the option to use chemical-looping technologies to produce H{sub 2} from fossil fuels with CO{sub 2} capture is explored. In chemical-looping combustion, direct contact between fuel and combustion air is avoided. Instead, a solid oxygen carrier performs the task of bringing oxygen from the air to the fuel. Thus, the resulting CO{sub 2} and H{sub 2}O are not diluted with N{sub 2}, and pure CO{sub 2} can easily be recovered by cooling and condensation. The heat of reaction is the same as for ordinary combustion. Chemical-looping reforming uses the same basic principles as chemical-looping combustion, but operates at under stoichiometric conditions. ...
As a part of a phenomenological model, a method for simulating the wall/jet interaction in a direct injection diesel engine is proposed. The method is based on the application of the momentum conservation equation in the different directions in which the wall jet is spread, and takes into account both the interaction with the combustion chamber geometry and with swirl. It takes as initial conditions the results of calculating the free jet, which is divided into packages. The predictions provide good agreement with those by other researchers. (author).
Processing concept that increases supply of jet fuel has been developed as part of study on methods for converting coal to hydrogen, methane, and jet fuel. Concept takes advantage of high aromatic content of coal-derived liquids to make high-octane gasoline, instead of destroying aromatics to make jet fuel.
This invention is comprised of an improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been ...
The Joint European Torus (JET) fusion machine is the only device capable of operation with tritium (as fuel) and Be (as plasma facing component), what makes it best suited to study ITER relevant issues. A large variety of activities are performed within the JET Fusion Technology Task Force. In this paper, some topics such as erosion/deposition and material transport, flakes characterization and detritiation techniques are highlighted. Recent results obtained using a pumping cryo-panel and on plasma facing component characterisation are given. Finally, issues that will be addressed in the forthcoming JET work-programme are presented, such as a beryllium main wall for JET and in-situ laser detritiation. (authors)
The goal of this research program has been to add to our understanding of the breakup of molten fuel jets penetrating reactor coolant. Easily handled working fluids are used to simulate fuel jet breakup, so that detailed observations may be obtained from a relatively large number of experiments. The tools used for observing this behavior are high speed notion picture photography, Flash X-radiography, and X-ray cine. Jet breakup lengths are determined from motion pictures; the mechanisms by which the jets are fragmented may be inferred from radiographs.
A zinc-air battery in a case including a zinc particle bed supported adjacent the current feeder and diaphragm on a porous support plate which holds the particles but passes electrolyte solution. Electrolyte is recycled through a conduit between the support plate and top of the bed by convective forces created by a density of differential caused by a higher concentration of high density discharge products in the interstices of the bed than in the electrolyte recycle conduit.
A zinc-air battery in a case is described including a zinc particle bed supported adjacent the current feeder and diaphragm on a porous support plate which holds the particles but passes electrolyte solution. Electrolyte is recycled through a conduit between the support plate and top of the bed by convective forces created by a density of differential caused by a higher concentration of high density discharge products in the interstices of the bed than in the electrolyte recycle conduit. 7 figures.
To clarify the effects of the principal factors that govern the thermal fragmentation of a molten metallic fuel jet in the course of fuel-coolant interaction, which is important in evaluating the sequence of core disruptive accidents (CDAs) for metallic fuel fast reactors, basic experiments were carried out using molten metallic fuel simulants (copper and silver) and a sodium pool.Fragmentation of a molten metal jet with a solid crust was caused by internal pressure produced by the boiling of sodium, which is locally entrapped inside the jet due to hydrodynamic motion between the jet and the coolant. The superheating and the latent heat of fusion of the jet are the principal factors governing this type of thermal fragmentation. On the other hand, the effect of the initial sodium temperature is regarded as negligible in the case of thermal conditions expected to result in CDAs for ...
In order to clarify a mechanism of melt-jet breakup and fragmentation entirely different from the mechanism of stripping, a series of experiments were carried out by using molten tin jets of 100 grams with initial temperatures from 250degC to 900degC. Molten tin jets with a small kinematic viscosity and a large thermal diffusivity were used to observe breakup and fragmentation of melt jets enhanced thermally and hydrodynamically. We observed jet columns with second-stage large-scale structures generated by the coalescence of large-scale structures recognized in the field of fluid mechanics. At a greater depth, the segmentation of jet columns between second-stage large-scale structures and the fragmentation of the segmented jet columns were observed. It is reasonable to consider that the segmentation and the fragmentation of ...
In order to predict the effect of a fuel-coolant interaction after a hypothetical core-melt-down accident, a phenomenological model has been developed to describe the thermal and hydrodynamic behavior of a high-temperature molten jet when it interacts with saturated or subcooled water in a film boiling regime. The mechanisms of jet-material erosion were analyzed by Kelvin-Helmholtz instabilities on the coherent column and by boundary layer stripping on the leading edge. The heat transfer coefficient, vapor-film thickness, and net steam generation, all of which strongly affect the jet-breakup behavior, were solved analytically. It was found that the jet breakup (or erosion) depends strongly on the steam generation from the jet/water interaction. The jet-breakup length (i.e., penetration distance) was found to be sensitive to the initial jet ...
A prototype hydride storage bed, using LaNi{sub 4.25}Al{sub 0.75} as the storage material, was fitted with strain gages to measure strains occurring in the stainless steel bed vessel caused by expansion of the storage powder upon uptake of hydrogen. The strain remained low in the bed as hydrogen was added, up to a bed loading of about 0.5 hydrogen to metal atom ratio (H/M). The strain then increased with increasing hydrogen loading ({approximately} 0.8 H/M). Different locations exhibited greatly different levels of maximum strain. In no case was the design stress of the vessel exceeded.
The performance of the gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator GARIS was investigated using 255No produced in the 238U(22Ne, 5n)255No reaction. Alpha particles of 255No separated with GARIS and transported by the gas-jet system were measured with a rotating wheel apparatus for ? spectrometry under low background condition. The high gas-jet efficiencies of about 75% were independent of the recoil ranges of 255No in the gas-jet chamber. The present results suggest that the GARIS/gas-jet system is a promising tool for the next-generation superheavy element chemistry: (1) the background radioactivities of unwanted reaction products are strongly suppressed, (2) the intense beam is absent in the gas-jet chamber and hence the high gas-jet efficiency is achieved, and (3) the beam-free condition also allows for ...
Introduction:Single-stream hydro-jet dissection is increasingly used in various laparoscopic procedures, but its use requires special equipment. We describe a simple method for using...Full Text Available
Heating and cooling by impinging jets is widely used in various engineering applications, due to the high heat transfer rates prevailing in the vicinity of the stagnation point. The authors have been able to utilize acoustically excited turbulence for the...
The studies of forced jet augmentation of natural convection heat transfer are introduced. It investigates experimentally mixed convection and heat transfer augmentation by forced jets in a large rectangular enclosure with a vertical cooling surface. The experiment is designed to measure the key parameters governing the heat transfer augmentation by a forced jet, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio, on conditions simulating those of actual passive containment cooling systems and scales approaching those of actual containment buildings or compartments. The tests that cover a variety of injection modes will contribute to reveal the nature of mixing and stratification phenomena under accident conditions to a new generation of inherently safe reactors. With similarity ...
This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the FluidizedBed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference cell suggests the ...
Experimental investigation of the length of single burning jets of methane and hydrogen previously diluted with an inert gas (nitrogen or helium) was carried out. Efflux of fuel gases into the atmosphere occurred through cylindrical extension pieces 4 and 8 mm in diameter. The Reynolds numbers at the cut of a piece varied in the range from 400 to 12,000. A clearly defined dependence of the jet length on the quality of the added inert gas is obtained. The correlation of experimental data made it possible to recommend formulas for engineering calculations of free laminar and turbulent jets.
Jet Propulsion Laboratory. California Institute of Technology. Pasadena, California. Energy and Water Conservation. Steve Rigdon. Facilities Energy Manager ...
A new multipellet long-pulse plasma fueling system is in operation on JET. In the initial experimental phase, a variety of plasma density profile shapes have been produced with peak to average values ranging up to 2.5 and peak plasma density up to 1.2 )times) 10/sup 20/m/sup )minus/3). 7 refs., 4 figs
The impingement of a fluid jet onto a surface has broad applications across many industries. Within the UK nuclear industry, during the final stages of fuel reprocessing, impinging fluid jets are utilised to mobilise settled sludge material within storage tanks and ponds in preparation for transfer and ultimate immobilisation through vitrification. Despite the extensive applications of impinging jets within the nuclear and other industries, the study of two-phase, solid loaded, impinging jets is limited, and generally restricted to computational modelling. Surprisingly, very little fundamental understanding of the turbulence structure within such fluid flows through experimental investigation is found within the literature. The physical modelling of impinging jet systems could successfully serve to aid computer model validation, determine operating requirements, evaluate plant ...
The authors present here several recent measurements involving associate production of photons and jets at the Tevatron. In particular, inclusive photon + met from D0, and photon + b-jets and photon + b-jet + leptons + MET from CDF are described in some detail. These measurements offer a good test of QCD predictions in rather complex final states.
The synthesis of experimental data concerning the effect of jet stagnation conditions on the drag of various afterbodies is presented. Jet pressure ratio effect on boattail pressure and on boundary layer separation is analyzed. This study is made for several values of the boundary layer thickness, taking into account the fact that some test rigs make its control possible by means of tangential blowing.
Plasma with a gas temperature below room temperature is not yet fully understood although it is expected to be an attractive tool for applications to material processing. In the present work, gas-temperature-dependent generation of a cryoplasma jet was studied. So far, we have generated a helium cryoplasma jet (296-5 K) under atmospheric pressure. At gas temperatures below 20 K, the helium excimer, He2, was observed clearly from by optical emission spectroscopy.
This research investigates experimentally mixed convection and heat transfer augmentation by forced jets in a large enclosure, at conditions simulating those of actual passive containment cooling systems and scales approaching those of actual containment buildings or compartments. The experiment was designed to measure the key parameters governing the heat transfer augmentation by forced jets and investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio. The tests cover a variety of injection modes leading to flow configurations of interest that contribute to reveal the nature of mixing and stratification phenomena in the containment under accident conditions of interest. The heat transfer of mixed convection can be predicted to be controlled by jet Archimedes number and geometric factors. ...
The past three years of work for the Air Force Office of Scientific Research has resulted in the development of a congenic mouse model of JP-8 jet fuel exposure, the role of substance P in the JP-8 jet fuel-induced lung injury process, and development of ...
In order to facilitate observations of low energy nuclear reactions, a new type recoil mass-separator together with a new gas-jet target system is being developed at the tandem accelerator facility in Kyushu University. The expected mass-resolving power of the separator is 220 for a solid angle of 10 msr and the practical thickness of the gas-jet target will exceed 0.1 atm#centre dot#cm for the light elements of H and He. (author).
To reduce fuel fouling in current U.S Navy and Air Force aircraft systems and to provide additional heat sink and thermal stability for future systems, the Air Force is developing an improved JP-8 jet fuel (JP-8 + 100). Two companies (Betz and Mobil) have...
A method is proposed for operating bed waters in an oil well by injecting silanes into the near-face zone. It is distinguished by the fact that in order to improve the effectiveness of insulation, the silanes used are silanes of general formula Si /SUB n/ H /SUB 2n-n/ .
This study investigated the effectiveness of dealing with biological waste by composting. In particular, it examined the feasibility of recovering excess thermal energy produced in the process of composting biological waste in terms of mass and energy transport parameters required in the aerated compost bed. An experiment was performed in which a 100 dm{sup 3} adiabatic, leak-tight reactor equipped with a controlled aeration system was constructed to study the temperature and pressure distribution in the bed. Sensors were used to determine the amount and humidity of emitted gases under variable external physical conditions. The perforated bottom of the reactor allowed for bed aeration. As such, the humidity and heat were transported upwards, forced by the air pumped in and by natural convection. In terms of pressure distribution inside the composted and aerated bed, the study results showed that there ...
We review the current status of resolved X-ray emission associated with extragalactic radio jets and hotspots. The primary question for any particular jet is to decide if the X-rays come from the synchrotron process or from inverse Compton scattering. There is considerable evidence supporting synchrotron emission for knots in the jets of FRI galaxies. For FRII terminal hotspots detected in the X-ray band, synchrotron self-Compton emission continues to provide viable models with one possible exception (so far). Inverse Compton scattering on photons of the cosmic microwave background is indicated for a few powerful jets, and is expected to be an important contributor if not the dominating mechanism for higher redshift objects. The application of a model generally yields physical parameters and in many cases, these include the Doppler boosting factor.
Apparent evolution of relativistic flows as traced by radio emission results from a combination of several factors related to propagation of relativistic blobs or shocks, velocity, density and pressure stratification of the underlying flow, plasma instability and (possibly also) phase and time travel effect. This combination can create an intricate and chaotic patterns of the observed morphological changes in radio emission, which complicates the analysis and interpretation of kinematic and physical properties of the jet plasma. Recent studies have indicated that slow and quasi-stationary patterns in jets are most likely formed by plasma instabilities while faster, superluminally moving patterns are related to highly relativistic plasma condensations produced by the nuclear flares. Some of the stationary patterns may also be related to recollimation shocks or locations where strong non-thermal continuum is produced in jets. ...
Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e{sup +}+p{yields}e{sup +}+n+jet+jet+X{sub r} have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb{sup -1}. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E{sub T}{sup jet}>6 GeV, neutron energy E{sub n}>400 GeV, and neutron production angle {theta}{sub n}<0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model.
This experimental research investigates mixed convection and heat transfer augmentation by gaseous forced jets in a large enclosure, at conditions simulating those of passive containment cooling systems for Gen III+ passively safe reactors. The experiment is designed to measure the key parameters governing heat transfer augmentation by forced jets, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio. The tests cover a variety of injection modes leading to flow configurations of interest for mixing and stratification phenomena in containments under accident conditions. Correlations for heat transfer augmentation by forced jets are developed and compared with experimental data. The characteristic recirculation speed inside the enclosure is introduced and analyzed. Steady stratified ...
This experimental research investigates mixed convection and heat transfer augmentation by gaseous forced jets in a large enclosure, at conditions simulating those of passive containment cooling systems for Gen III+ passively safe reactors. The experiment is designed to measure the key parameters governing heat transfer augmentation by forced jets, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio. The tests cover a variety of injection modes leading to flow configurations of interest for mixing and stratification phenomena in containments under accident conditions. Correlations for heat transfer augmentation by forced jets are developed and compared with experimental data. The characteristic recirculation speed inside the enclosure is introduced and analyzed. Steady stratified ...
We have developed a liquid jet injector system that can be used for hydrated sample delivery at X-ray Free Electron Laser (XFEL) sources and 3rd generation synchrotron sources. The injector is based on the Gas Dynamic Virtual Nozzle (GDVN), which generates a liquid jet with diameter ranging from 300 nm to 20 {\\mu}m without the clogging problems associated with conventional Rayleigh jets. An improved nozzle design is presented here. A differential pumping system protects the vacuum chamber and an in-vacuum microscope allows observation of the liquid jet for diagnostics while it is being exposed to the X-ray beam. A fiber optically coupled pump laser illuminating the jet is incorporated for pump-probe experiments. First results with this injector system have been obtained at the LCLS.
Abstract in english A simplified model for drying solids in the constant rate period in a batch fluidised bed was developed.It assumes the bed to be divided into dense and bubble phases with heat and mass transfer between the phases.The model predicts the constant-rate drying period, provided the fluid bed shape and material characteristics are known.The model is compared with experimental data reported in the literature covering a wide range of materials, gas flow rates, column diameters, m (more) aterial hold-ups, air temperatures and humidities.Model predictions compare satisfactorily with the experimental data.
The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s.
Context. The high energies of protostellar jets, implied by recent observations of X-rays from such flows, came very much as a surprise. Inferred shock velocities are considerably higher than what was previously known, hence putting even larger energy demands on the driving sources of the jets. The statistics of X-ray emitting jets are still poor, yet a few cases exist which seem to imply a correlation between the presence of HeI 1.0830 mu emission and X-ray radiation in a given source. Aims. This tentative correlation needs confirmation and explanation. If the jet regions of HeI 1.0830 mu emission are closely associated with those producing X-rays, high resolution infared spectroscopy can be used to observationally study the velocity fields in the hot plasma regions of the jets. This would provide the necessary evidence to test and further develop theoretical models of ...
In this work the authors study the stabilization point of a lifted, reacting jet of nitrogen diluted methane in co-flowing air. The jet flow is acoustically forced so as to organize the large scale vortical structures. The validation of the numerical results is possible through a concurrent experimental investigation of a similar planar jet. The use of an acoustically forced planar jet allows for significant savings by the restriction of the computation to two dimensions; the model is otherwise applicable in three dimensions. The authors based their study on the following parameters, which are derived from the experimental setup: a jet width of 1.16 cm, a mean jet velocity of 0.8 m/s, and a coflow velocity of 0.1 m/s. The acoustical forcing is studied at frequencies of 7.5 MHz and 90 MHz, which have been established experimentally as being characteristic of two ...
Being able to distinguish light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover, a combination of two simple variables, the charge track multiplicity and the pT-weighted linear radial moment (girth), can achieve similar results. While this pair appears very promising, our study is only Monte Carlo based, and other discriminants may work better with real data in a realistic experimental environment. To that end, we explore many other observables constructed using different jet sizes and parameters, and highlight those that deserve further ...
One way to intensify heat and mass transfer processes in column-type equipment is through use of contact devices with directional gas phase injection into a liquid. Making the perforations at an angle to the tray plane permits a rise in the permissible gas velocity in the column, since inertial force adds to gravity during separation. Different arrangements of the jet-forming elements relative to one another and to partitions and baffle-type contacts installed on the trays can improve phase contact conditions and intensify heat and mass transfer. Design of jet-type trays for a specific purpose requires that the influence of jet-forming, element design parameters on at least the fluid dynamic situation on the tray be known. In this work, the authors evaluate the influence of tab bend-up angle on jet tray working characteristics. These investigations demonstrate that the jet ...
The objective was to study the interaction of a side jet with the incoming supersonic flow and hypersonic flow. Qualitatively same Cp trends have been obtained as found experimentally. Also in aerodynamic coefficients side jet interaction results in additional pitching moment which is because of the high pressure region in upstream of the jet and a low pressure region in the downstream of the jet. Also jet interaction results in the rise in the lift coefficient. Whereas in the incidence case, simulation has been performed for the hypersonic flows over a biconic body with supersonic lateral jet at Mach 9.7 and incidence of 0"o to incidence of -12"o and 12"o. The results obtained were compared with the experimental and CFD code CFL3D results. PAK-3D over predicts the surface pressure as compared to the CFL3D and experimental results, whereas the qualitative trends ...
Summary Objective Community-based information on the delivery and use of health interventions is important to monitor the effectiveness of the Roll Back Malaria programme. However, community surveys to determine coverage for insecticide-treated bed nets are time-consuming and costly. We wanted to assess whether schoolchildren's reports of household ownership of a bed net and coverage among high-risk groups monitored by schoolteachers through a questionnaire could be used as a proxy of household ownership of bed net and coverage at community level, for routine monitoring of malaria control programmes. Method 3602 schoolchildren in 39 randomly selected schools and 2798 heads of households in 39 villages were interviewed about their use of either insecticide-treated or untreated bed nets. Res...
Purpose The aim of this study was to evaluate the role of host periosteum and recipient bed perforation on the healing of an onlay graft to the mandible based on histologic and immunohistochemical analysis. Materials and methods Each of the 12 adult sheep used in the study received four iliac corticocancellous onlay bone grafts on the lateral surface of the mandible. In experiment 1, the block graft was placed in direct contact with the recipient bed and fixed with micro-screws, and in experiment 2, the recipient cortical bed was perforated before graft placement. The host periosteum around the graft was excised before flap replacement in experiment 3, and in experiment 4, a sheet of silicone membrane was placed between the graft and the recipient bed. The animals were euthanised at 4, 8, ...
Although the standard model of particle physics agrees perfectly with experimental data, it is unlikely the final theory describing particles and their interactions. New phenomena has been searched in the jets and missing transverse energy topology. Such phenomena may be due to the pair production of leptoquarks decaying into a quark and a neutrino or the pair production of stops decaying into a charm and a neutralino which is assumed to be the lightest supersymmetric particle. These searches have been performed with the Ddiamter detector at hadronic collider TeVatron with a center of mass energy of 1.96 TeV. This kind of searches needs a good understanding of the jet energy calibration. The determination of the relative jet energy scale has allowed us to reduce the systematic uncertainties on the jet energy measurement when comparing the data and the simulation. Moreover a new method has been developed ...
The concentration and distribution of a soil fumigant in the subsurface of field plots are two key factors in the determination of the fumigant efficacy. Subsurface concentrations of the biologically active compounds cis- and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) were determined in soil at two adjacent injection traces and midpoint between the two traces in plastic-covered field beds after injection of the fumigant Telone C35 by conventional chisels or by a coulter rig (Avenger coulters). Two of the four beds were covered with metallic polyethylene film (MPE) and the remaining two were covered with virtually impermeable film (VIF). Three hours after chisel injection, concentrations of the three compounds at the two adjacent injection traces in the two beds were highly variable. Large concentrations of the compounds were detected at the side traces, whereas the compounds were not detected at the middle ...
Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (both radioactive and hazardous according to the Resource Conservation and Recovery Act) wastes. Depending on regulatory requirements, the mercury in the off-gas must be controlled with sometimes very high efficiencies. Compliance to the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Several test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include: (a) The depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests, (b) MERSORB(reg_sign) carbon can sorb Hg up to 19 wt% of the carbon mass, and (c) the spent carbon ...
We present a Hubble Space Telescope image of the FRII radio galaxy 3C 401, obtained at 1.6 microns with the NICMOS camera in which we identify the infrared counterpart of the brightest region of the radio jet. The jet has a complex radio structure and brightens where bending occurs, most likely as a result of relativistic beaming. We analyze archival data in the radio, optical and X-ray bands and we derive its spectral energy distribution. Differently from all of the previously known optical extragalactic jets, the jet in 3C401 is not detected in the X-rays even in a long 48ksec X-ray Chandra exposure and the infrared emission dominates the overall SED. We propose that the dominant radiation mechanism of this jet is synchrotron. The low X-ray emission is then caused by two different effects: i) the lack of any strong external photon field and ii) the shape of the electron ...
We report results of the 2006 April multi-wavelengths campaign of SS 433, focusing on X-ray data observed with Suzaku at two orbital phases (in- and out-of- eclipse) and simultaneous optical spectroscopic observations. By analyzing the Fe25 K_alpha lines originating from the jets, we detect rapid variability of the Doppler shifts, dz/dt ~ 0.019/0.33 day^-1, which is larger than those expected from the precession and/or nodding motion. This phenomenon probably corresponding to "jitter" motions observed for the first time in X-rays, for which significant variability both in the jet angle and intrinsic speed is required. From the time lag of optical Doppler curves from those of X-rays, we estimate the distance of the optical jets from the base to be ~(3-4) \\times 10^14 cm. Based on the radiatively cooling jet model, we determine the innermost temperature of the jets to be T_0 = 13 +/- ...
It is well known that composite armors, consisting of glass elements confined with metallic tampers, are extraordinarily effective against shaped charge attack. Early experiments showed that jets fired against glass targets appeared to be bombarded by tiny fragments that destroyed alignment and reduced residual jet penetration. This result was attributed to an elastic rebound effect in which the outward radial motion of the target around the jet periphery was supposed to be arrested by tensile hoop stresses which developed behind the divergent shock front. Glass fragments were then accelerated radially inward and these destabilized the jet. To sustain the large tensile hoop stresses required, the glass must not have been fractured by the initial shock, behind which the stress state is typically well above the Hugoniot elastic limit. Modeling the penetration of a jet into glass ...
A transition from petroleum~derived jet fuels to blends with Fischer-Tropsch (F~T) fuels, and ultimately fully synthetic hydro-isomerized F-T fuels has raised concern about the fate of plasticizers in nitrile-butadiene rubber a-rings that are contacted by the fuels as this transition occurs. The partitioning of plasticizers and fuel molecules between nitrile a-rings and petroleum-derived, synthetic, and additized-synthetic jet fuels has been measured. Thermal desorption of o-rings soaked in the various jet fuels followed by gas chromatographic analysis with a mass spectrometric detector showed many of the plasticizer and stabilizer compounds were removed from the o-rings regardless of the contact fuel. Fuel molecules were observed to migrate into the o-rings for the petroleum-derived fuel as did both the fuel and additive for a synthetic F-T jet fuel additized with benzyl alcohol, but less for the ...
We present the results of a study on the 1.4 GHz kpc-scale radio emission in the complete flux density limited MOJAVE sample, comprising 135 radio-loud AGNs. While extended emission is detected in the majority of the sources, about 7% of the sources exhibit only radio core emission. Many BL Lacs exhibit extended radio power and kpc-scale morphology typical of powerful FRII jets, while a substantial number of quasars possess radio powers intermediate between FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme, which links BL Lacs to FRIs and quasars to FRIIs. We find a significant correlation between extended radio emission and pc-scale jet speeds: the more radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or low frequency) radio emission is indeed related to jet kinetic power. Various properties such as extended radio power and apparent pc-scale ...
We present an analytical model for jets in Fanaroff & Riley Class I (FRI) radio galaxies, in which an initially laminar, relativistic flow is surrounded by a shear layer. We apply the appropriate conservation laws to constrain the jet parameters, starting the model where the radio emission is observed to brighten abruptly. We assume that the laminar flow fills the jet there and that pressure balance with the surroundings is maintained from that point outwards. Entrainment continuously injects new material into the jet and forms a shear layer, which contains material from both the environment and the laminar core. The shear layer expands rapidly with distance until finally the core disappears, and all of the material is mixed into the shear layer. Beyond this point, the shear layer expands in a cone and decelerates smoothly. We apply our model to the well-observed FRI source 3C31 and show that there ...
we report an ultrafast synchrotron x-ray phase contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. We demonstrate that there exist great similarities in the phenomenology of primary breakup with that of the secondary breakup. Especially, a membrane-mediated breakup mechanism dominates the breakup process for a wide range of air speeds. This finding reveals the intrinsic connections of these two breakup regimes and has deep implications on the unified theoretical approach in treating the breakup mechanism of high speed liquid jet.
The performance of a high temperature ion source coupled to a helium gas-jet transport system for an efficient mass separation of neutron-rich alkaline earth and lanthanide isotopes is reported and the results of overall efficiency measurements using different cluster materials in the gas-jet are given. A fast, microprocessor controlled tape transport system for ..gamma..-spectroscopic studies on short-lived isotopes is described. Some results on the decay of 3.8sub(-s) /sup 152/Pr are presented. (orig.).
The performance of a high temperature ion source coupled to a helium gas-jet transport system for an efficient mass separation of neutron-rich alkaline earth and lanthanide isotopes is reported and the results of overall efficiency measurements using different cluster materials in the gas-jet are given. A fast, microprocessor controlled tape transport system for ..gamma..-spectroscopic studies on short-lived isotopes is described. Some results on the decay of 3.8sub(-s) /sup 152/Pr are presented.
With the help of heat balance equation and high temperature thermodynamic function, the calibration relation of jet temperature with discharge power, gas flow rate was obtained for nitrogen thermal plasma. It was shown that the results were agreed with the principle of similarity. The jet temperature was a function of Peff/f, instead of a general two variables function of Peff and f, which were effective discharge power and working gas flow rate, respectively. A related discussion has been given; it will be referable to thermal plasma applications. (authors)
Unsteady impinging jets are systematically controlled with respect to their time dependence in order to investigate the influence of unsteadiness on the heat transfer performance. This is achieved by a special mass flow control device, which allows almost arbitrary shapes of unsteadiness to be imposed onto the impinging jet. Three different standard signals (sinusoidal, triangular, rectangular) and two specially designed signals are applied and their influence on heat transfer is determined in terms of an enhancement factor. Heat transfer augmentation up to 30% was found and could be physically explained with the help of PIV and hot-wire measurements of the flow field.
Engine flow simulation was provided by four separately mounted air ejectors connected to a high-pressure air supply. The engine nacelle center lines were ...
Jan 13, 2011 ... This 360-degree mosaic of images from the navigation camera on ... The Radiation Assessment Detector, shown prior to its September 2010 ...
or third generation fuels. These are biofuels that can directly substitute for gasoline, jet fuel, and diesel. Today more than 9 billion gallons of biofuels are produced annually...
A high-density gas jet supersonic nozzle is reported in this paper. The jitter and actuation time of the nozzle is determined by the pin discharge and laser spark radiation respectively. The jitter time of the nozzle is within 10 ?s with the backing pressure as high as 25 bar. With a nanosecond laser pulse focused on the gas jet about 1 mm below the nozzle, the actuation time is calculated to be about 15 ms by detecting the laser produced spark radiation, which reveals the existence of the gas jet and the relative gas density evolving with time. Consequently the gas density is estimated to be well above 1019 cm-3, compared with theoretical simulations from the nozzle parameters.
We present a HST/STIS spectroscopic and optical/radio imaging study of the Seyfert NGC 2110 aiming to measure the dynamics and understand the nature of the nuclear outflow in the galaxy. Previous HST studies have revealed the presence of a linear structure in the Narrow-Line Region (NLR) aligned with the radio jet. We show that this structure is strongly accelerated, probably by the jet, but is unlikely to be entrained in the jet flow. The ionisation properties of this structure are consistent with photoionisation of dusty, dense gas by the active nucleus. We present a plausible geometrical model for the NLR, bringing together various components of the nuclear environment of the galaxy. We highlight the importance of the circum-nuclear disc in determining the appearance of the emission line gas and the morphology of the jet. From the dynamics of the emission line gas, we place constraints on the ...
Jan 18, 2011 ... The Radiation Assessment Detector, shown prior to its September 2010 ... This 360-degree panorama shows the vista from the location where ...
Smoothing of laser beam non-uniformities using gas jets has been studied. The experiment has been performed with the PALS (Prague Asterix Laser System) laser working at 0.44 ?m with an intensity of about 1015 W/cm2. The laser beam has been split in two by a prism thus creating an artificial large-scale non-uniformity (? 90 ?m). We recorded time resolved and static images of laser-gas jet interaction with and without an Al target. Multi 1-dimensional and 2-dimensional simulations show that such interaction acts redistributing the over-intensities over larger surface. This effect has to be attributed to ionization processes with consequent laser beam refraction. Results show that Argon gas jet produces a strong refraction of the laser beam thus strongly reducing the initial two spots separation. (authors)
lytical Comparison of Turbine-Blade Cooling System Designed for a. TurboJet Engine Operat- at Supersonic Speed and Altitude. I1 -. Air-C~Oling Systems. ...
Jun 30, 2003 ... He graduated from training with top honors and served as a parachute rigger and paratrooper for the 82nd airborne division at Fort Bragg, ...
... The phenol and cresylic acid stream is flashed in a thin film evaporator over a concentrated sulfuric acid mixture to remove pyridine type substances ...
Boiling jet impingement cooling is currently being explored to cool power electronics components. In hybrid vehicles, inverters are used for DC-AC conversion. These inverters involve a number of insulated-gate bipolar transistors (IGBTs), which are used as on/off switches. The heat dissipated in these transistors can result in heat fluxes of up to 200 W/cm{sup 2}, which makes the thermal management problem quite important. In this paper, turbulent jet impingement involving nucleate boiling is explored numerically. The framework for these computations is the CFD code FLUENT. For nucleate boiling, the Eulerian multiphase model is used. The numerical results for boiling water and R113 jets (submerged) are validated against existing experimental data in the literature. Some representative IGBT package simulations that use R134a as the cooling fluid are also presented. (author)
A Self-Powered Underwater Robot for Ocean Exploration and Beyond ... first unmanned underwater vehicle (UUV) that is completely powered by renewable energy . ...
star formation. To either side of the center, a small bar of dust and gas is helping to fuel the new stars. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the...
material may survive intact and mix back into interstellar gas clouds, helping to fuel the next generation of stars. NASA's Jet Propulsion Laboratory, Pasadena, Calif.,...
Mar 2, 2010 ... The NASA/JPL Education Office works with educators -- both classroom teachers and informal educators -- to provide tools, resources and ...
For the performance analysis of Canadian deuterium uranium (CANDU) reactor shutdown system number 2 (SDS2), a computational fluid dynamics model of poison jet flow has been developed to estimate the flow field and poison concentration formed inside the CANDU reactor calandria. As the ratio of calandria shell radius over injection nozzle hole diameter is so large (1055), it is impractical to develop a full-size model encompassing the whole calandria shell. In order to reduce the model to a manageable size, a quarter of one-pitch length segment of the shell was modeled using symmetric nature of the jet; and the injected jet was treated as a source term to avoid the modeling difficulty caused by the big difference of the hole sizes. For the analysis of an actual CANDU-6 SDS2 poison injection, the grid structure was determined based on the results of two-dimensional real- and source-jet simulations. The ...
Mechanisms, AGARD Conference Proceedings No. 131, 1974, Paper No. 11. ... Olsen, W. and Karchmer, A., Lip Noise Generated by Flow Separation From Nozzle ...
May 1, 2011 ... Abstract: Diatek Corporation, San Diego, CA and the Jet Propulsion Lab developed the Diatek Model 7000 aural thermometer which weighs ...
this, however, was a real environmental threat since various drums containing jet fuel, Bunker C, diesel and other petroleum derivatives were on fire. The CAPECO...
of different transportation fuels (e.g., gasoline, diesel fuel, aviation gasoline, jet fuel, residual fuel oil). Subsequent calculations are performed to estimate the share...
activities, including the combustion of diesel fuel in heavy-duty vehicles and jet fuel in aircrafts. Current details on emissions from the transportation and other...
The force required to break the conidium-conidiophore attachment in Helminthosporium maydis was measured by centrifugation and by a small jet of air. The force which removed half the...Full Text Available
The jet in cross flow (JICF) is a basic flowfield which is relevant to a wide variety of applications which are described to provide context for JICF investigations. Material consistent with the scope of topics presented at the 72nd AGARD Fluid Dynamics Panel Meeting and Symposium on Computational and Experimental Assessment of Jets in Cross Flow on 19-22 April 1993 in Winchester, U.K. is summarized. The JICF research was divided into three time periods: (1) early research - up to 1970, (2) research during the 1970's, and (3) research since 1980. The following areas of experimental activity are discussed; the definition of an effective correlation parameter; the jet flowfield including the jet trajectories, cross-section shape, and jet induced pressures; the effects of jet deflection angle, nozzle shape, pressure ratio, velocity decay, and temperature; and the ...
cellulosic biofuel volumes for consumption as transportation fuel, heating oil, or jet fuel in the U.S. in 2011. We also evaluated the production and import potential for...
and used to reduce or replace petroleum-based transportation fuel, heating oil or jet fuel). In addition, this rule includes a new regulatory provision establishing a...
Mar 15, 2011 ... The NASA/JPL Education Office works with educators -- both classroom teachers and informal educators -- to provide tools, resources and ...
from a military fuel storage facility released about 80,000 gallons of kerosine-based jet fuel. Immediate and extensive recovery measures managed to contain the spill, but...
from a military fuel storage facility released about 80,000 gallons of kerosine-based jet fuel. Immediate and extensive recovery measures managed to contain the spill, but...
Barlow, Nadine Northern Arizona University, Flagstaff, AZ. 10. Barker, Don NASA Johnson Space Center, TX. 11. Beaty, David NASA Jet Propulsion Laboratory, ...
but one test point on the flight cards was achieved before we hit our "bingo," or minimal fuel remaining, and we had to land. The radar was developed by NASA's Jet Propulsion...
...identified as oil when the shipment document accurately describes the material as: aviation fuel, diesel fuel, fuel oil, gasoline, jet fuel, kerosene, motor fuel, or...
Air Show. The exhibit will feature 16 fuel companies showcasing cutting-edge alternative jet fuel technologies. In addition to individual company exhibits, the Showcase will...
Post-drive imaging included 360-degree view by the navigation camera and .... Sol 938: Opportunity completed another assessment of the clarity of the sky. ...
For light water reactors, loss of coolant is an important point in safety analysis, whereas for gas-cooled reactors the ingress of water into the core region is an incident of safety relevance. The applicability of the computer code system GAMTEREX to pebble beds of spherical high-temperature gas-cooled reactor fuel elements with simulated water ingress is verified by experiment. The measurements were performed at a Siemens-Argonaut reactor, using its ring core as a driver zone for a pebble-bed core in the center of the reactor.
Carbon monoxide, H{sub 2}, and CO{sub 2} in synthesis gas can be converted to CH{sub 4} by employing a triculture of Rhodospirillum rubrum, Methanosarcina barkeri, and Methanobacterium formicicum. Trickle-bed reactors have been found to be effective for this conversion because of their high mass-transfer coefficients. This paper compares results obtained for the conversion of synthesis gas to CH{sub 4} in 5-cm- and 16.5-cm-diameter trickle-bed reactors. Mass-transfer and scale-up parameters are defined, and light requirements for R. rubrum are considered in bioreactor design.
Direct electric heating by passing an electrical current directly through a bed of adsorbent may prove to be an efficient means of regenerating activated charcoal in continuous and batch adsorption processes. Obvious advantages of this type of regeneration are its almost complete lack of inertia, which makes it possible to reduce the number and dimensions of the adsorbers, and its highly efficient use of energy due to the small number of steps in the conversion of the energy, as well as the reduction of heat losses involved in warming the structure and making up for losses to the surroundings. The authors consider the kinetics of direct electric heating of a stationary bed of activated charcoal not containing adsorbed substances.
The H-Coal ebullated bed reactor contains at least four discrete components: gas, liquid, catalyst, and unconverted coal and ash. Because of the complexity created by these four components, it is desirable to understand the fluid dynamics of the system. The objective of this program is to establish the dependence of the ebullated bed fluid dynamics on process parameters. This will permit improved control of the ebullated bed reactor. Progress has been made in the study undertaken for defining the hydrodynamic properties of gas/liquid/solid systems as related to the H-Coal process. The literature search was completed, and a report will be issued shortly. Design and construction of the fluid dynamics unit proceeded as planned. Unit completion is scheduled for May 1, 1978.
Available in abstract form only. Full text of publication follows: In this study. simulation of carbon dioxide absorption by Sodium Hydroxide solution in a packed bed has been investigated. At first, mass and energy balances were applied around a differential height of the bed. So, the governing equations were obtained. Surface renewal theory by Danckwerts was used to represent the mass transfer operation Finally, by changing the operating parameters like solvent temperature, inlet gas composition pressure and height of the bed, the effect of these parameters on the absorption and the composition of carbon dioxide in exit stream have been investigated. (authors)
The objective of this study was to determine the direct actions of nitroprusside and nitroglycerin on the pulmonary vascular bed in the intactchest dog. These widely used nitrogen oxide-containing vasodilator...Full Text Available
your eye to the SCN in your brain, so that light ... Owls are individuals who go to bed late, like to get up late in the moming. And the moming types, ...
Greenman J, Thorn RMS, Saad S, Austin AJ. In vitro diffusion bed, 3-day repeat challenge `capacity' test for antimicrobial wound dressings. Int Wound J 2006;3:322-329. Abstract The aim of this study was to develop an in vitro wound infection model that allows the comparison of the bacterial kill rate of antimicrobial wound dressings over the course of 3 days, with renewed microbial challenges each day, under realistic wound-like conditions. A test bed model of a moderately exuding wound was constructed from a hydrogel containing releasable foetal calf serum (FCS), and cellulose discs dosed with test microbes (Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa) suspended in 50% FCS applied at the interface between the test dressing and the hydrogel test bed. Freshly prep...
... laws between particles (modeling UGV/UAV/UUV collectives) to ... A mobile robot test-bed is used in ... of this work on mobile robots executing pursuit ...
The effect of air addition on biomass tar conversion in catalytic packed bed crackers was studied using both an isothermal micro reactor and a fluidised bed bench scale biomass gasification set up with down stream tar crackers. The micro reactor was applied for experiments with artificial biomass producer gas containing naphthalene as a model tar compound. Experiments were carried out with inert silica and catalytically active calcined dolomite bed material both with and without air addition. Experimental results with real tar from the fluidised bed bench scale gasification set up were in qualitative agreement with results from the micro reactor experiments. (author)
This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to ...
This thesis presents the work achieved to instrument the ATLAS software framework, ATHENA, with a library of tools and utensils for the physics analysis as well as the extraction of the jet energy scale using physics events (in-situ calibration). The software part presents the various components of the ATHENA framework which handles the simulated and reconstructed data flow as well as the different stages of this process, before and during the data taking. The building of a library of tools easing the reconstruction of physics objects, their association with Monte-Carlo particles and their API is then explained. The need for common language and collaboration-wide utensils is emphasised as it allows to share the workload of validating these tools and to get reproducible physics results. The analysis part deals with the implementation of a light jet energy scale calibration algorithm within the C++ framework. This calibration algorithm makes use ...
The new collaborative exploitation of the JET Facilities requires suitable technical tools and infrastructure measures to enable the Remote Participation of scientists from all European Fusion labs. Such measures are being gradually introduced. They comprise of a toolkit for Remote Data Access, Remote Computer Access and for teleconferencing, and of infrastructure measures that address network connectivity, network security, shared documentation and technical support.
Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields and dynamics. Data were analysed using Proper Orthogonal Decomposition (POD). An important periodic event is an elongation of the jet core cross section that results in a downstream displacement of the jet towards the chamber wall.
The importance of neutron measurements both as a succinct measure of the progress to fusion ignition using the magnetic confinement route and also as a diagnostic of plasma conditions is discussed. The various neutron diagnostic systems that have been or are being constructed by AERE Harwell for JET are described. The properties to be measured by such diagnostics are clearly identified and some results obtained with the installed diagnostics during d-d plasmas are presented.
One of several methods to build YSZ electrolyte of SOFC is plasma spraying. This system heats particle to a melting point and then pushing them into target and forming a deposition. This paper presents heating studies of YSZ particle in plasma jet. By simple model it is shown that the required time such those YSZ particle with grain size of 50 ?m to be melt is around 12 x 10-4 second. (author)
The apex dimensions and length are calculated as a function of current for the ion-emitting jet in liquid-metal ion sources (LMIS). The results agree well with observations. Since the final expressions are analytical, they give more insight into the fundamental mechanisms involved than do numerical calculations. Some implications of the model are discussed concerning focused ion beam (FIB) systems employing LMIS. (author).
There are five tasks within this project on thermally stable coal-based jet fuels. Progress on each of the tasks is described. Task 1, Investigation of the quantitative degradation chemistry of fuels, has 5 subtasks which are described: Literature review on thermal stability of jet fuels; Pyrolytic and catalytic reactions of potential endothermic fuels: cis- and trans-decalin; Use of site specific {sup 13}C-labeling to examine the thermal stressing of 1-phenylhexane: A case study for the determination of reaction kinetics in complex fuel mixtures versus model compound studies; Estimation of critical temperatures of jet fuels; and Surface effects on deposit formation in a flow reactor system. Under Task 2, Investigation of incipient deposition, the subtask reported is Uncertainty analysis on growth and deposition of particles during heating of coal-derived aviation gas turbine fuels; under Task 3, Characterization of solid ...
We present H-alpha and [O III] (5007 Angstroms) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5m Isaac Newton Telescope (INT). The ring-like structure is luminous in [O III] and there exists a thin outer shell with a high [O III] / H-alpha flux ratio. This outer shell probably originates in the collisionally excited atoms close to the front of the bow shock. Its presence indicates that the gas is shock excited as opposed to photoionised, supporting the jet-powered scenario. The shock velocity was previously constrained at 20 = 100 km/s (1 sigma confidence) based on a comparison of the observed [O III] / H-alpha ratio in the bow shock with a number of radiative shock models. From this we further constrain the time-averaged power of the jet: P_Jet = (4 - 14)*10^36 erg/s. The H-alpha flux behind the shock front is typically 4*10^-15 ...
Plasma nitriding of a Ti substrate is carried out under a low ambient pressure below 3kPa, and a plasma torch is prepared on a trial basis which is provided with a supersonic expansion nozzle considered to expand plasma jet optimally and to be effective for suppressing the occurrence of shock wave. The system used for the study is provided with a specimen holder having the function of adjusting the distance between the nozzle outlet and the substrate inside the vacuum chamber which is provided with a plasma torch in the flange member. The plasma torch is so structured that a supersonic expansion nozzle can be installed at the tip of the plasma torch. In this process wherein plasma jet is employed, hard nitrided layer can be formed by plasma irradiation for a short time even under such low pressure as less than 3kPa by setting adequate experimental conditions. It is made clear that the use of a supersonic nozzle corresponding to the internal ...
The ink jet printing technology is a relatively novel technique in development of organic electronic devices. The technique consists of working out depositions of organic layers by a piezo-based ink jet printer. In this work polymer conducting films deposited by ink jet printing technique on different plastic substrates has been demonstrated. The poly(3,4-ethylenedioxythiofene)/poly(4-styrenesulfonate) [PEDOT/PSS] and glycerol-modified PEDOT/PSS [G-PEDOT/PSS] were used like conducting inks to be applied on polyester and polyethylene terephthalate (PET) substrates. By means of the change of substrate associated to the deposition number or type of polymer ink used for printing of the conducting films, the sheet resistance can be modified. Such a behavior suggests that plastic substrate fulfills an important role for the changing of sheet resistance of the PEDOT/PSS and G-PEDOT/PSS films made by ink jet ...
The authors discuss a two-phase two-component experimental system developed to study enhancement of heat transfer from a vertical chip size heater to surrounding liquid (Freon 113 or Ethanol) due to air jet impingement. Heat transfer coefficient was measured as function of jet velocity, heat flux and the distance between exit of jet tube and heated surface. The injector was placed very close to the hot surface. It was found that the heat transfer was notably enhanced with foreign gas impingement, especially in the cases of small temperature differences between wall and coolant. In fact for higher jet velocities the heat transfer coefficients tended to infinite while the temperature differences between wall and coolant were zero. The heat transfer coefficients decreased with the increasing of heat flux. High-speed camera was used to study the behaviour of the gas bubbles which play very important role in ...
The need is substantiated for using remote control of technological processes on blowout dangerous beds. A method is proposed for this control based on recording with the help of AGZ apparatus for gas release into the roadway. Distinguishing features are indicated for the change in methane concentration in the roadway with normal occurrence of the process and in the case of blowout of coal and gas.
The coal bed methane (CBM) potential of five coal zones (the Kootenay, Gething, Gates, Brazeau, and Coalspur) in the Alberta foothills and mountains is re-evaluated. For evaluation, the coal zones are divided into shallow (200 to 2500 m depth) and deep (over 2500 m depth). The total gas content is estimated. Recommendations on how to obtain more reliable resource data and about producibility are included. 41 refs., 12 figs., 3 tabs., 2 apps.
The possibility of modifying the functional composition of humic acids by gas-phase ozonation of bed-oxidized brown coal was examined. About 90% of the organic matter of brown coal was converted to low-molecular weight soluble oxygen-containing products by stepwise liquid-phase ozonation (in chloroform and acetic acid).
In this paper the possibility of configuring a water cooled Nuclear Thermal Propulsion (NTP) rocket, based on a Particle Bed Reactor (PBR) is investigated. This rocket will be used to operate on water obtained from near earth objects. The conclusions reached in this paper indicate that it is possible to configure a PBR based NTP rocket to operate on water and meet the mission requirements envisioned for it. No insurmountable technology issues have been identified.
Most of the Turkish lignites have undesired fuel properties and they are extremely polluting. In this study, Sweet Sorghum was chosen as the energy plant. Combustion experiments of lignite and lignite-Sweet Sorghum mixtures were carried out in a fluidised bed system. The fuel-feeding ratio was set such that the thermal output of the system remained constant. Addition of Sweet Sorghum to the lignite reduces the pollutant concentration. The results were supported by experimental results.
Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the column was deuterated ...
Cattle or chicken manure is pelletized, and a bed of the pellets is combusted at the bottom to create a temperature gradient and to generate a fuel gas. Thus, an approximately 25 cm-high bed of approximately 5 mm-diameter chicken manure pellets was combusted to produce a fuel gas of 1622 kcal/kg manure.
A total of nine papers were presented at the course with the following titles: peat accumulation and coal basins; coal composition; coal quality; sedimentary environments of coal; generation, storage and migration of natural gas in coal bed reservoirs; geophysical log interpretation; the Ardley coal zone of central Alberta; stratigraphy and sedimentary environment of the Coalspur Formation; and the coal-bearing Luscar Group of western Alberta. All of these papers have been abstracted separately.
Background and Purpose: Total-body irradiation (TBI) is an important part of the conditioning regimen for hematopoietic stem cell transplantation (HSCT) in patients with hematologic malignancies. The results after treatment with various TBI regimes were compared, and dose-effect relationships for the endpoints relapse incidence, disease-free survival, treatment-related mortality, and overall survival were derived. The aim was to define requirements for an optimal treatment schedule with respect to leukemic cell kill and late normal-tissue morbidity. Material and Methods: A literature search was performed. Three randomized studies, four studies comparing results of two or three TBI regimens, and nine reports with results of one specific TBI regimen were identified. Biologically effective doses (BEDs) were calculated. The results of the randomized studies and the studies comparing results of two or three TBI regimens were pooled, and the pooled relative risk (RR) was ...
Background and Purpose: Total-body irradiation (TBI) is an important part of the conditioning regimen for hematopoietic stem cell transplantation (HSCT) in patients with hematologic malignancies. The results after treatment with various TBI regimes were compared, and dose-effect relationships for the endpoints relapse incidence, disease-free survival, treatment-related mortality, and overall survival were derived. The aim was to define requirements for an optimal treatment schedule with respect to leukemic cell kill and late normal-tissue morbidity. Material and Methods: A literature search was performed. Three randomized studies, four studies comparing results of two or three TBI regimens, and nine reports with results of one specific TBI regimen were identified. Biologically effective doses (BEDs) were calculated. The results of the randomized studies and the studies comparing results of two or three TBI regimens were pooled, and the pooled relative risk (RR) was ...
In the isolated rat mesenteric bed, the 1 min perfusion with 100 nm anandamide, a concentration that did not evoke vasorelaxation, elicited an acute release of 165.1 ± 9.2 pmol nitric...Full Text Available
During the erection of the Sandia 34-Meter VAWT Test Bed, the induced gravitational stress state in the turbine blades and their associated deflections were measured. This manuscript details the measurements that were taken on the Test Bed blades during erection and compares them to the stresses and deflections predicted by the NASTRAN finite element code.
A gas-fired boiler plant comprises a burner bed extending over a flat surface and heat exchanger pipes arranged above the burner bed, parallel to the said surface. The heat exchanger tubes comprise pipes equipped with a pluraltiy of flat ribs which extend substantially radially from the said pipes and which are provided in space arrangement over the length of the said heat exchanger pipes. The ribs are provided with bent-off portions. The hot flue gases rising from the burner bed flow through the gaps formed between the said ribs and pipes. In order to improve both the convective heat transmission and the utilization of the radiant heat, the bent-over edges are inclined, at least partly, relative to the surface of said burner bed, the arrangement being selected in a manner to ensure that bent-over portions point towards the burner bed and the rising flue gased are guided around the ...
We have investigated the diffusion enhancement mechanism of boron-enhanced diffusion (BED), wherein boron diffusivity is enhanced four to five times over the equilibrium diffusivity at 1050&hthinsp;{degree}C in the proximity of a silicon layer containing a high boron concentration. It is demonstrated that BED is driven by excess interstitials injected from the high boron concentration layer during annealing. For evaporated layers, BED is observed above a threshold boron concentration between 1{percent} and 10{percent}, though it appears to be closer to 1{percent} for B-implanted layers. For sub-keV B implants above the threshold, BED dominates over the contribution from transient-enhanced diffusion to junction depth. For 0.5 keV B, this threshold implantation dose lies between 3{times}10{sup 14} and 1{times}10{sup 15} cm{sup {minus}2}. It is proposed that the excess interstitials responsible for ...
We have investigated the diffusion enhancement mechanism of boron-enhanced diffusion (BED), wherein boron diffusivity is enhanced four to five times over the equilibrium diffusivity at 1050 ampersand hthinsp;degree C in the proximity of a silicon layer containing a high boron concentration. It is demonstrated that BED is driven by excess interstitials injected from the high boron concentration layer during annealing. For evaporated layers, BED is observed above a threshold boron concentration between 1% and 10%, though it appears to be closer to 1% for B-implanted layers. For sub-keV B implants above the threshold, BED dominates over the contribution from transient-enhanced diffusion to junction depth. For 0.5 keV B, this threshold implantation dose lies between 3x10"1"4 and 1x10"1"5 cm"-"2. It is proposed that the excess interstitials responsible for BED are produced during the ...
Inverted annular flow can be visualized as a liquid jet-like core surrounded by a vapor annulus. While many analytical and experimental studies of heat transfer in this regime have been performed, there is very little understanding of the basic hydrodynamics of the post-CHF flow field. However, a recent experimental study was done that was able to successfully investigate the effects of various steady-state inlet flow parameters on the post-CHF hydrodynamics of the film boiling of a single phase liquid jet. This study was carried out by means of a visual photographic analysis of an idealized single phase core inverted annular flow initial geometry (single phase liquid jet core surrounded by a coaxial annulus of gas). In order to extend this study, a subsequent flow visualization of an idealized two-phase core inverted annular flow geometry (two-phase central jet core, surrounded by a coaxial annulus of ...
The production of heavy crude oils increased in the last years in the world. Crude oils with high density, viscosity, acidity and sulfur, nitrogen, metals and asphaltenes contents, by the others hand, low stability and low product quality. The challenger of many refiners is find solutions to refine the heavy crude oils, and produce fuels with certify quality, such as Jet Fuel. The principal aviation technique on the world work with gas turbines engines feted for jet fuel (JET A1). The quality specifications of this fuel are establish by International Norms: ASTM-1655, DEF STAN 91-91-3 (DERD 2494) and joint Fuelling System Check List. The world technologies to obtain jet fuel from mixtures of heavy crude oil with middle crude oils are: Atmospheric distillation, with a posterior hydrogenation and finally the additivation. Studies carried out have demonstrates that the Cubans heavy crude oils is ...
The objective of this paper is to reveal to what degree bio-based jet fuels (bio-jet) can reduce greenhouse gas (GHG) emissions from the US aviation sector. A model of the supply and demand chain of bio-jet involving farmers, bio-refineries, airlines, and policymakers is developed by considering factors that drive the decisions of actors (i.e. decision-makers and stakeholders) in the life cycle stages. Two kinds of feedstock are considered: oil-producing feedstock (i.e. camelina and algae) and lignocellulosic biomass (i.e. corn stover, switchgrass, and short rotation woody crops). By factoring in farmer/ feedstock producer and bio-refinery profitability requirements, land availability and suitability, as well as a time delay factor, a more realistic estimate of the level of bio-jet supply and emissions reduction can be developed under different oil price assumptions. Factors that drive ...
New ICRH antennas on JET were designed to couple to the new JET divertor plasma configurations and to improve the Fast Wave Current Drive (FWCD) capabilities. The A2 antenna consists of 4 straps whose currents can be phased at arbitrary angles. The real time automatic tuning acts on frequency, line length (line phase shifters) and stub length. Provision is made for the coupling resistance/plasma position feedback to accommodate the fast changes in antenna loading. The first coupling, tuning and heating results are reported in 0{pi}0{pi}, 0000 and 00{pi}{pi} phasing. A new antenna model is described, which was developed to simulate the measured antenna loading in terms of plasma parameters and to provide a starting point for the real time automatic tuning. 5 refs., 4 figs.
We report on the discovery of kinematic shock signatures associated with a localized radio jet interaction in the merging Seyfert galaxy NGC 5929. We explore the velocity-dependent ionization structure of the gas and find that low-ionization gas at the interaction site is significantly more disturbed than high-ionization gas, which we attribute to a local enhancement of shock ionization due to the influence of the jet. The characteristic width of the broad low-ionization emission is consistent with shock velocities predicted from the ionization conditions of the gas. We interpret the relative prominence of shocks to the high density of gas in the nuclear environment of the galaxy and place some constraints of their importance as feedback mechanisms in Seyferts.
This patent describes a method of hydraulically mining a surface of a mining location comprising: a. determining the dimensions of the surface of the mining location from a fixed point at the location; b. constructing at a second location remote from the mining location a visual representation of the surface form the determined dimensions of the mining location with respect to the fixed point; c. jetting water under high pressure against a selected area on the surface of the mining location; d. determining changes in the dimensions of the selected area of the surface of the mining location; e. reconstructing at the second location a new visual representation of the surface from the determined changes of the location during the jetting of the water; and f. redirecting the jetted water under high pressure utilizing data from the reconstructed visual representation.
We present evidence in favour of a link between the luminosity radiatively dissipated in the central engine of radio-loud Active Galactic Nuclei and the kinetic power in their jets. This piece of evidence is based on the relation we find between the luminosity in broad emission lines and the kinetic power in pc-scale radio jets, for a sample of radio-loud quasars for which suitable data are available in the literature. We find that the ionizing luminosity and the kinetic one are of the same order of magnitude, suggesting that the processes responsible for them are somehow related. A strong magnetic field in equipartition with the radiation field could be responsible for regulating both processes. BL Lac objects seem to follow a similar behaviour, but with comparatively fainter broad line emission.
The association of at least some long gamma-ray bursts with type Ic supernova explosions has been established beyond reasonable doubt. Theoretically, the challenge is to explain the presence of a light hyper-relativistic flow propagating through a massive stellar core without losing those properties. We discuss the role of the jet-star interaction in shaping the properties of the outflow emerging on the surface of the star. We show that the nature of the inner engine is hidden from the observer for most of the evolution, well beyond the time of the jet breakout on the stellar surface. The discussion is based on analytical considerations as well as high resolution numerical simulations. Finally, the observational consequences of the scenario are addressed in light of the present capabilities.
Displacement Ventilation (DV) offers a great opportunity to improve indoor air quality while reducing the energy consumption compared to mixing ventilation. A frequent problem with displacement ventilation is however the draft discomfort caused by the cold air movement at foot level and excessive temperature difference between head and ankle. Despite numerous past studies, there is still a lack of detailed data regarding the velocity and temperature distribution inside DV jets. In this experimental study, measurements of the air velocity and temperature are performed in the DV jet produced by a flat wall-mounted DV diffuser, using a fine mesh focused on the 0.00-0.20 m height range. Two supply conditions are studied. Three planes of measurements are covered: the vertical longitudinal plane...
This paper provides information on heat transfer enhancement due to jet mixing inside a cylindrical enclosure. The work addresses conservative heat transfer assumptions regarding mixing and condensation that have typically been incorporated into passive containment design analyses. The current research presents an interesting possibility for increasing decay heat removal of passive containment systems under combined natural and forced convection. Eliminating these conservative assumptions could provide the basis for a change of containment design and reduce the construction cost. It is found that the ratio of forced- and free convection Nusselt numbers can be predicted as a function of the Archimedes number and a correlated factor accounting for jet orientation and enclosure geometry. To use the small-scale tests for large containment design, scale-up methods and criteria are important for matching the key governing parameters and fluid ...
Interbedded limestones and dolomites of the Cambrian Conococheague Formation cropping out northwest of Lancaster exhibit contrasting rheological behavior during deformation. Dolomite beds are uncleaved and form concentric F[sub 1] recumbent folds with hinges trending northeast, parallel to the trend of the Appalachian orogen. Limestone beds show subhorizontal S[sub 1] cleavage with southeast-plunging extension lineations defined by fibrous calcite and ubiquitous smear lineations. In limestone beds, intrafolial F[sub 1] folds with curvilinear hinges are sheath folds flattened in the S[sub 1] cleavage. In zones of most intense shear, F[sub 1] hinges parallel the regional northwest directed tectonic transport direction. In 1969, the author attributed the variation in intrafolial F[sub 1] fold-hinge orientation to hinge-parallel buckling due to constrictional bulk strain. This interpretation, however, is not consistent with the ...
The aim with this project sponsored by Energimyndigheten is to develop a method for calculations of grate boilers fueled by bark. This report describes this project, 'Evaluation Method for Grate Combustion' (EMGC). CFD codes is an engineering tool applicable in the area of the over-grate section called the furnace. This part of the boiler is easy to model for an experienced CFD code user and the results are usually quite satisfactory for evaluating the combustion process in general. Various gas phases reactions and related combustion processes over the burning bed can be simulated including air staging, fuel staging and SNCR. However the simulation needs information of amount and properties of the burning bed products, entering the furnace. The simulation of the in-furnace processes without this information is often just a numerical speculation. A predictive mathematical model based on physical and chemical data for the grate ...
fuel are produced from a barrel of crude oil by U.S. refiners. Other products such as jet fuel and heating oil make up the remaining one third. Graphic of a barrel of oil...
The astronomical number of letters handled by the Post Office makes automatic sorting technology essential. Key roles are played by the postcode system and an ink-jet printer that has been developed to use phosphorescent inks.
The ratio of particle velocity to translation speed exceeds 1 for 98% of .... The westward movement of the meandering jet and eddy system transports nutrient- rich ...... J. Hydrometeor., 4, 1044-1066. Gedney, N., P. M. Cox, H. Douville, ...
The bright gamma-ray burst GRB050525a has been detected with the Swift observatory, providing unique multiwavelength coverage from the very earliest phases of the burst. The X-ray and optical/UV afterglow decay light curves both exhibit a steeper slope ~0.15 days after the burst, indicative of a jet break. The timing of the jet break combined with the total gamma-ray energy of the burst constrains the opening angle of the jet to be 2.5 degrees. We derive an empirical `time-lag' redshift from the BAT data of z_hat = 0.69 +/- 0.02, in good agreement with the spectroscopic redshift of 0.61. Prior to the jet break, the X-ray data can be modelled by a simple power law with index alpha = -1.2. However after 300s the X-ray flux brightens by about 30% compared to the power-law fit. The optical/UV data have a more complex decay, with evidence of a rapidly falling reverse shock component that dominates in the ...
Electrospinning, a flexible jet-based fiber, scaffold, and membrane fabrication approach, has been elucidated as having significance to the heath sciences. Its capabilities have been most impressive...Full Text Available
The performance of jet fuel with an oxidant mixture containing 70 percent liquid fluorine and 30 percent liquid oxygen by weight was investigated in a 500-pound-thrust engine operating at a chamber pressure of 300 pounds per square inch absolute. A one-oxidant-on-one-fuel skewed-hole impinging-jet injector was evaluated in a chamber of characteristic length equal to 50 inches. A maximum experimental specific impulse of 268 pound-seconds per pound was obtained at 25 percent fuel, which corresponds to 96 percent of the maximum theoretical specific impulse based on frozen composition expansion. The maximum characteristic velocity obtained was 6050 feet per second at 23 percent fuel, or 94 percent of the theoretical maximum. The average thrust coefficient was 1.38 for the 500-pound thrust combustion-chamber nozzle used, which was 99 percent of the theoretical (frozen) maximum. Mixtures of fluorine and oxygen were found to be self-igniting with ...
million for advanced energy projects Thu, Sep 29, 2011 - Project Aims to Bring Bio-based Jet Fuel Production to the Northwest Mon, Sep 12, 2011 - Drive like the wind Thu, Aug 25,...
Persistently high concentrations of carbon monoxide and low-altitude ozone in the air of the Nation's major urban centers led Congress in the 1990 Clean Air Act Amendments to mandate changes to the composition of gasoline and diesel fuel. Those gasoline c...
To clarify the fragmentation mechanism of a molten metallic fuel jet in a sodium pool under high-ejection-velocity conditions that correspond to the medium- and high-burnup conditions in the metallic fuel core of liquid-metal-cooled fast breeder reactors, a series of experiments with molten copper as a metallic fuel simulant and a sodium pool was carried out. Under low-ejection-velocity conditions in the range of an ambient Weber number (Wea) a ? 200, the size of the fragments is confirmed to be almost independent of the initial superheating of the jet. Furthermore, the size of the fragments agrees well with that evaluated using the Rayleigh-Taylor instability model, in which the fragment size is assumed to be equal to half the fastest growing wavelength. This result is qualitatively consistent with the characteristics that the molten jet column with large inertia force owing to the high ejection velocity, which transports ...
Nebulised antibiotics have been shown to be beneficial in the treatment of lung infections in cystic fibrosis. Studies on the efficiency of nebuliser systems are constantly required in view of the large...Full Text Available
MWo = average molecular weight of fuel est. 105 g/mole for gasoline est. 165 g/mole for Jet fuel est. 230 g/mole for diesel fuel MWX = molecular weight of selected chemical...
to end statewide burn ban 09/28/2011 - Commissioner's statement on $80 million biomass to jet fuel award to UW and WSU Media Center | View All News Meetings & Events Saturday Oct...
Objective:This the first of two articles reviewing the scientific literature on the evaluation and treatment of circadian rhythm sleep disorders (CRSDs), employing the methodology...Full Text Available
This contribution presents different approaches for the modeling of gas entrainment under water by a plunging jet. Since the generation of bubbles happens on a scale which is smaller than the bubbles, this process cannot be resolved in meso-scale simulations, which include the full length of the jet and its environment. This is why the gas entrainment has to be modeled in meso-scale simulations. In the frame of a Euler-Euler simulation, the local morphology of the phases has to be considered in the drag model. For example, the gas is a continuous phase above the water level but bubbly below the water level. Various drag models are tested and their influence on the gas void fraction below the water level is discussed. The algebraic interface area density (AIAD) model applies a drag coefficient for bubbles and a different drag coefficient for the free surface. If the AIAD model is used for the simulation of impinging jets, ...
This volume is divided into the following sections: (1) fundamentals of convection heat transfer; (2) fundamentals of heat transfer with impinging jets; and (3) fundamentals of heat transfer augmentation. Separate abstracts were prepared for most papers in this volume.
An impinging jet is a widely used technique for realizing high heat-transfer rates between a fluid and a surface. However, the area of enhanced heat transfer is limited to the neighborhood of the stagnation point. In this study, heat transfer is augmented remote from the stagnation point in an impinging plane jet system by a rod array located near the wall. Each square rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The distance between the nozzle and the flat plate (H) and the spacing between the rods and the flat plate surface (C) were changed to find the optimum values. The largest heat-transfer augmentation was obtained for C = 1 mm, H/B = 10, where the jet nozzle width is B. In this case, the heat-transfer coefficient averaged over an area 2B from the stagnation point is about 1.6 times greater compared to that without a rod array.
Kerf geometry, kerf wall features, and cutting front characteristics of an Abrasive Waterjet (AWJ) machined Graphite/Epoxy (Gr/Ep) laminate were studied. A macroscopic analyses suggests that geometrical features associated with AWJ machining of Gr/Ep laminates are influenced by three macro regions along the cutting depth. The presence of these regions, including initial damage at jet entry, smooth cutting, and rough cutting near the jet exit, depends on the operating conditions. Design of experiments and analysis of variance were used to determine the effect of cutting parameters on kerf characteristics and to develop empirical models for kerf profile and features of the three distinct macroscopic regions. Cutting front analysis revealed that the mechanisms of material removal in AWJ machining of Gr/Ep do not change over the jet penetration depth. In general, high quality uniform cuts may be obtained by minimizing initial ...
The evolution of FRI jets has been long studied in the framework of the FRI-FRII dichotomy. In this paper, we test the present theoretical and observational models via a relativistic numerical simulation of the jets in the radio galaxy 3C 31. We use the parameters derived from the modelling presented by \\cite{lb02a,lb02b} as input parameters for the simulation of the evolution of the source, thus assuming that they have not varied over the lifetime of the source. We simulate about 10 % of the total lifetime of the jets in 3C 31. Realistic density and pressure gradients for the atmosphere are used. The simulation includes an equation of state for a two-component relativistic gas that allows a separate treatment of leptonic and baryonic matter. We compare our results with the modelling of the observational data of the source. Our results show that the bow shock evolves self-similarly at a quasi-constant speed, with slight ...
Radon concentration in the bed rooms, kitchens, sitting rooms and TV lounges in some houses in the Lahore has been measured using CN-85 Solid State Nuclear Track Detectors in box type dosimeters. Maximum value of radon concentration is 93 Bq/m/sup 3/ in a bed room whereas the minimum value is 25 Bq/m/ sup 3/ in a TV lounge. The average value of radon concentration in bed rooms, kitchens, sitting rooms and TV lounges varies between 43 Bq/m/sup 3/ and 55 Bq/m/sup 3/. Comparison of radon concentration in the old and new houses has been done and no specific relationship has been observed. (author).
Sandia National Laboratories has developed a family of airfoils specifically designed for use in the equatorial portion of a Vertical-Axis Wind Turbine (VAWT) blade. An airfoil of that family has been incorporated into the rotor blades of the DOE/Sandia 34-m diameter VAWT Test Bed. The airfoil and rotor design process is reviewed. Comparisons with data recently acquired from flow visualization tests and from the DOE/Sandia 34-m diameter VAWT Test Bed illustrate the success that was achieved in the design. The economic optimization model used in the design is described and used to evaluate the effect of modifications to the current Test Bed blade. 1 tab., 11 figs., 13 refs.
A high pressure waterjet has been used to study the surface roughening of superalloys as preparation for thermal spraying. Designed experiments for Mar-M 509 and Rene 80 were carried out for the effects of jet pressure and mass of water delivered per unit area. Comparisons were made of several superalloys in terms of erosion, surface roughness and topology. The mechanism of jet erosion of Rene 80 was studied in relation to its metallurgical microstructure. An MCrAlY coating by shrouded plasma spray was made over a waterjet prepared surface with excellent bonding and having an ideally clean interface.
This student manual, part of a small-engine repair series on servicing fuel systems, is designed for use by special needs students in Texas. The manual explains in pictures and short sentences, written on a low reading level, the job of servicing two-piece flo-jet carburetors. Along with the steps of this repair job, specific safety and caution information is frequently noted. To reinforce consistency in material presented to the slow learners, the pictures and written words correspond exactly with the pictures and wording on a corresponding audiovisual presentation. A progress chart for rating the students is included in the manual. (KC)
This report beings with a historical overview on the origin and early beginnings of Radiant Energy Power Source for Jet Aircraft. The report reviews the work done in Phase I (Grant DE-FG01-82CE-15144) and then gives a discussion of Phase II (Grant DE-FG01-86CE-15301). Included is a reasonably detailed discussion of photovoltaic cells and the research and development needed in this area. The report closes with a historical perspective and summary related to situations historically encountered on projects of this nature. 15 refs.
This report beings with a historical overview on the origin and early beginnings of Radiant Energy Power Source for Jet Aircraft. The report reviews the work done in Phase I (Grant DE-FG01-82CE-15144) and then gives a discussion of Phase II (Grant DE-FG01-86CE-15301). Included is a reasonably detailed discussion of photovoltaic cells and the research and development needed in this area. The report closes with a historical perspective and summary related to situations historically encountered on projects of this nature. 15 refs.
The deuterium inventory at JET after 2001-2004 operational campaign has been determined using nuclear reaction analysis (NRA) and secondary ion mass spectrometry (SIMS). A full poloidal set of divertor tiles and a set of outer poloidal limiter (OPL) tiles were analysed providing an estimation for the total deuterium retention of about 66 g. Deuterium is trapped mainly at the inner divertor on horizontal target tile and at the inner divertor louvre area where ?60% of the trapped D is found. The long-term D retention is ?4% of the total D input.
The uranium target of a gas jet transport system for fission products has been modified by the addition of an aluminum cover foil. The new modification allows fission fragments of low mass to enter a continuous chemistry system while heavier fragments are stopped in the aluminum. The elimination of the heavier homologues allows development of simpler and faster chemical separation procedures. In addition, since the lighter fragments are slowed down by the cover foil a smaller target chamber can be used. This leads to a reduction in system holdup time.
The uranium target of a gas jet transport system for fission products has been modified by the addition of an aluminum cover foil. The new modification allows fission fragments of low mass to enter a continuous chemistry system while heavier fragments are stopped in the aluminum. The elimination of the heavier homologues allows development of simpler and faster chemical separation procedures. In addition, since the lighter fragments are slowed down by the cover foil a smaller target chamber can be used. This leads to a reduction in system holdup time. (orig.).
We present results for a complete set of polarization observables for jet production in lepton proton collision, where the final state lepton is not observed. The calculations are carried out in collinear factorization at the level of Born diagrams. For all the observables we also provide numerical estimates for typical kinematics of a potential future Electron Ion Collider. On the basis of this numerical study, the prospects for the transverse single target spin asymmetry are particularly promising. This observable is given by a certain quark-gluon correlation function, which has a direct relation to the transverse momentum dependent Sivers parton distribution.
The objective of the program was to develop a domestic cooktop with low-NOx emissions and high efficiency. During the first two phases of the program, three design concepts were developed, and two versions of developmental prototypes using the IR-Jet approach were fabricated and tested. The third phase was initiated to address the design issues of a simmer setting, air/gas metering, and jet plate durability and to develop prototypes for interested manufacturers.
Abstract First results showing the viability of combining laser chemical processing (LCP) and aerosol jet printing (AJP) technologies to produce a high-efficiency front side for silicon solar cells are presented. LCP simultaneously opens the anti-reflection coating (ARC) and highly dopes the underlying silicon to create a selective emitter, while AJP is the first in a two-step fine-line contact formation procedure. The electrical properties as well as the morphology of the resulting structures are presented. Performance similar to that achieved with evaporated TiPdAg metallization is demonstrated. Copyright 2010 John Wiley & Sons, Ltd.
The inelastic scattering of the beam and the residual gas molecules in RHIC could represent one of the limitations on the beam life time and emittance growth. This report covers the dominant central nuclear collisions influence on the beam lifetime and transverse emittance growth. The cross sections for the beam-gas electron radiative captures are an order of magnitude smaller. The capture cross sections include the radiative and non-radiative capture, and the capture from the electron-positron pair creation from the 'vacuum capture'.
Washboard (WB) modes (Smeulders P et al 1999 Plasma Phys. Control. Fusion 41 1303) are a very common edge instability regularly observed in the H-mode regime in JET. They are detected as (normally several) bands of continuously fluctuating magnetic activity rotating in the direction of the electron diamagnetic drift with typical frequencies in the range of 10-90 kHz. The time evolution of the WB mode frequency is found to follow qualitatively the evolution of the electron temperature measured near the pedestal top, probably due to the strong diamagnetic drift associated with the large pedestal gradients. Evidence for their involvement in the pedestal and ELM dynamics will be presented. Increasing WB mode amplitude is correlated with an increase in the time between consecutive type-I ELMs. In situations in which a sudden increase (decrease) of WB mode activity is observed, the build-up of the pedestal temperature (and, linked to this, also of the pedestal pressure) ...
This paper explores effects of differential diffusion in nonpremixed turbulent jet flames. Pulsed Raman scattering spectroscopy is used to measure temperature and species concentrations in chemically reacting jets of H{sub 2}/CO{sub 2} into air, over a range of jet Reynolds numbers from 1,000 to 30,000 based on cold jet fluid properties. Results show significant effects of differential diffusion at all jet Reynolds numbers considered. Differential diffusion between H{sub 2} and C0{sub 2} produces differences between the hydrogen element mixture fraction ({xi}{sub H}) and the carbon element mixture fraction ({xi}{sub c}). The greatest effects occur on the rich side of stoichiometric, where {xi}{sub H} is observed to be smaller than {xi}{sub C} at all Reynolds numbers. Differential diffusion between H{sub 2} and H{sub 2}O creates a net flux of hydrogen element toward the ...
Concerning heat transfer augmentation of an axisymmetric impinging jet using a perforated plate set, the bore of the hole in the plate for local and averge heat transfer rate, pitch, and effect of the distance between perforated plate and target plate were examined. Heat transfer augmentation was examined under the condition of 0.063 /ge/d/D /ge/0.200, 1.25 /ge/p/d /ge/4.00, Re is approximately equal to 18000, (where d is the bore of the hole in the plate, D is the axisymmetric nozzle outlet bore, p is the pitch of the perforated plate, and Re is the jet Reynolds number). The findings are as follows; The velocity of the small jet after passing the perforated plate is reduced, and resistance to disturbance is remarkably large. The small jet which is not at the center hole extends to the outside of the plate. The heat transfer rate at a stagnation point is high when the target plate is placed in the ...
An original dc double anode plasma torch which provides a long-time and highly stable atmospheric plasma jet has been devised for the purpose of hazardous waste treatment. The arc fluctuations and dynamic behaviour of the argon and argon-nitrogen plasma jets under different operating conditions have been investigated by means of classical tools, such as the statistic method, fast Fourier transform (FFT) and correlation analysis. In our experiments, the takeover mode is identified as the fluctuation characteristic of the argon plasma jet while the restrike mode is typical in the argon-nitrogen plasma dynamic behaviour. In the case of pure argon, the FFT and correlation calculation results of electrical signals exhibit the only characteristic frequency of 150 Hz, which originates from the torch power and is independent of any change in the operating conditions. It indicates that the nature of fluctuations in an argon plasma ...
A computer code ICRKFLO was used to simulate the multiphase reacting flow of fluidized catalytic cracking (FCC) riser reactors. The simulation provided a fundamental understanding of the hydrodynamics and heat transfer processes in an FCC riser reactor, critical to the development of a new high performance unit. The code was able to make predictions that are in good agreement with available pilot-scale test data. Computational results indicate that the heat transfer and droplet evaporation processes have a significant impact on the performance of a pilot-scale FCC unit. The impact could become even greater on scale-up units.
A public health emergency such as an influenza pandemic will lead to shortages of mechanical ventilators, critical care beds, and other potentially life saving treatments. This will raise difficult...Full Text Available
Thalassinid shrimp cause significant problems for oyster aquaculture in the Pacific Northwest (USA) where oysters succumb to the physical disruption of the sediment by the burrowing activity of these animals. While electrofishing is a commonly used technique to capture fish and some invertebrates i...
Refractory ascites can occur in patients with various conditions. Although several procedures based on the reinfusion of ascitic fluid have been reported after the failure of bed rest, salt and water...Full Text Available
The gas-solid reaction and breakthrough curves in the fixed-bed reactor are of great importance, and being influenced by a number of factors makes the prediction of these factors a difficult problem. In this study, the reaction rate between solid sorbents and hydrogen chloride gas at high temperature was first investigated. On the basis of a fixed-bed reactor, the experimental results were analyzed by the shrinking core model of diffusion and surface chemical reaction control. The results showed that reaction rates of two sorbents with hydrogen chloride gas were controlled by the combination of the surface chemical reaction and diffusion of product layers, and the reaction rates nearly keep constant within 15 h of the initial reaction period and then decrease gradually. The results of the breakthrough curves show that solid sorbents in the fixed-bed reactor are capable of reducing the HCl level to near-zero levels at ...
The juxtacapsular BNST (jcBNST) is activated in response to basolateral amygdala (BLA) inputs through the stria terminalis and projects back to the anterior BLA and to the central nucleus of...Full Text Available
This article puts the case for coal fired combined cycle gas turbine (CCGT) power plants. The need to gasify the coal for the CCGT, use of fluidised bed combustors or gasification systems, the difference in prices of coal and natural gas, and coal and natural gas reserves are discussed. (UK)
The goal of this research project was to determine the eff ects of geometric and mechanical parameters characterizing the soil-structure interaction developed in a buried pipe installation. Parameters such as pipe ring stiff ness, bedding thickness, trenc...
Outpatient practice after percutaneous coronary intervention (PCI) is gaining momentum due to constantly optimizing results. Furthermore, the availability of limited beds to handle the large volume...Full Text Available
In Syrian hamsters (Mesocricetus auratus), the expression of reproductive behavior requires the perception of social odors. The behavioral response to these odors is mediated...Full Text Available
Anaerobic treatment of a volatile fatty acid (VFA) mixture was investigated under psychrophilic (3 to 8°C) conditions in two laboratory-scale expanded granular sludge bed reactor stages in series....Full Text Available
A new method for computing petroleum reserves which takes into account the volumetric elasticity of stratal petroleum and a porous medium of a collector is examined based on the example of developing petroleum beds of Cretaceous horizon of the Groznenskiy region.
Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture...Full Text Available
The sensitivities to cefuroxime and cephradine of potentially pathogenic bacteria isolated in two British general hospitals comprising 900 beds have been assessed. In a three-month period 2537 strains...Full Text Available
This paper presents the design and implementation of a clinical picture archiving and communication system (PACS) module within the radiology department of a 700-bed teaching hospital. The system is...Full Text Available
Most hospitals today are quickly developing special programs and services that are designed to compete for physicians and patients, and ultimately fill unoccupied beds. In an attempt to attract physicians...Full Text Available
In fluid bed processing in the chemical, food or pharmaceutical industries, pneumatic nozzles are typically used to convert binder or coating liquids into droplets. Producing fine droplets from liquids in a gas phase is termed atomisation, and it involves complex phenomena which are not yet fully understood. This paper provides a systematic and up-to-date review of two-fluid nozzle designs and principles together with a presentation of nozzle fundamentals introducing basic nozzle theory and thermodynamics. Correlations for the prediction of mean droplet diameters are reviewed, compared and accompanied by a discussion of their use.
Three dimensional temperature field and helium flow field of TBM are simulated using the general purpose computational fluid dynamics (CFD) code FLUENT. The temperature distribution of Be Armor, Be Pebble Bed, Li_4SiO_4 Pebble Bed, Structure Material of TBM, and helium flow field in the cooling pipe are presented. The research indicates that the work temperature of each material is under the material temperature allowed except some places where high temperature should be excluded in the design. The results will provide references for further optimized thermal hydraulic design of ITER China TBM. (authors)
In the prevention of atmospheric pollution by sulfur dioxide emissions from acid absorbers in contact process sulfuric acid plants in which the unconverted SO/sub 2/ is accumulated by adsorption in a zeolite adsorbent bed and desorbed back into the acid production system, it is found that ambient moist air, after partial dehydration in an acid scrubber is suitably used both to cool down and hot purge desorb the zeolite beds. In addition the pure water derived from the ambient air is advantageously used in the acid-making system.
System-level-operational testing of the ETX-II test-bed electric vehicle is described and the results discussed. Because the traction battery is a major factor in the performance of an electric vehicle, previously reported work on the sodium-sulfur battery designed for use with the ETX-II is reviewed in detail. Chassis dynamometer performance of the test-bed vehicle met or exceeded design goals and compared reasonably well with SIMPLEV computer modeling results. Areas are identified wherein further work is needed to establish a firmer basis for comparison of the simulation and the observed results.
The technology of nuclear direct propulsion orbit transfer systems based on the Particle Bed Reactor (PBR) is described. A 200 megawatt illustrative design is presented for LEO to GEO and other high #DELTA#V missions. The PBR-NOTV can be used in a one-way mode with the shuttle or an expendable launch vehicle, e.g., the Titan 34D7, or as a two-way reusable space tug. In the one-way mode, payload capacity is almost three times greater than that of chemical OTV's. PBR technology status is described and development needs outlined.
The author presents a mathematical model for analysis of the impact of scrubber bed length, porosity, and gas flow rate on the absorption of CO{sub 2} in a breathing apparatus. The model accounts for the decrease in available absorbent through chemical conversion. The predicted efflux of CO{sub 2} from a canister containing LiOH compared favorably with measured values reported elsewhere. It was determined from a computational study that the time for breakthrough of CO{sub 2} at a prescribed level is nearly directly proportional to bed length and inversely proportional to gas flow and porosity.
Diffusion of radon in a bed of activated charcoal is described by diffusion equations. An analytical solution of these equations is presented for the case of constant radon concentration in the atmosphere. The solutions are given separately for short term and long term exposure. An analytical form of the calibration constant f for long term exposure and constant radon concentration in air, was found. A numerical method and computer code based on the method of finite elements is developed for the case of variable radon concentration in air. This program simulates radon adsorption by the activated charcoal bed, enabling determination of sensitivity. The dependence of sensitivity on different parameters, such as temperature, thickness of the charcoal, etc. was studied using this program. (orig.) 10 refs.
No research has compared expressions of weight bias across different subgroups of obese individuals. This study compared attitudes toward and beliefs about obesity in women with and without binge eating disorder (BED) and examined whether these attitudes are related to psychological factors. Fifty obese women with BED were compared with an age- and body mass index (BMI)-matched group of 50 obese women without BED on a battery of established measures of anti-fat attitudes and beliefs about weight controllability and psychological factors (self-esteem, depression, and eating disorder features). The ageand BMI-matched groups did not differ with respect to beliefs about obesity or attitudes toward obese persons, or in self-esteem or depression. Correlational analyses conducted separately within each group revealed that women with BED who reported more favorable attitudes towards obese persons had higher ...
During earlier work rapid and highly sensitive Jet-REMPI (resonance-enhanced multiphoton ionization) mass spectrometry was applied for monitoring the effluent from thermal treatment of a filter dust during a de novo test under laboratory conditions. The sample, from ESP-Field 2 of an iron ore sintering plant, was already loaded with dioxins ({sigma}PCDD/F = 132 ng/g), their precursors (PCBz, PCPh) and other products of incomplete combustion. Heating filter dust in a temperature window 200-350 C under a flow of air results in further formation of these pollutants. As described elsewhere, on-line detection was mostly carried out using a non-selective ionization mode, to measure a wide range of compounds simultaneously. The changes of output suggest that the reaction products increase in chlorination level with time. Another explanation is that higherchlorinated compounds appear later as a consequence of lower volatility and stronger adsorption. However, due to mass ...
The Federal Aviation Administration (FAA) identified 17 accidents that may have resulted from fuel tank explosions on commercial aircraft from 1959 to 2001. Seven events involved JP 4 or JP 4/Jet A mixtures that are no longer used for commercial aircraft fuel. The remaining 10 events involved Jet A or Jet A1 fuels that are in current use by the commercial aircraft industry. Four fuel tank explosions occurred in center wing tanks (CWTs) where on-board appliances can potentially transfer heat to the tank. These tanks are designated as ''Heated Center Wing Tanks'' (HCWT). Since 1996, the FAA has significantly increased the rate at which it has mandated airworthiness directives (ADs) directed at elimination of ignition sources. This effort includes the adoption, in 2001, of Special Federal Aviation Regulation 88 of 14 CFR part 21 (SFAR 88 ''Fuel Tank System Fault Tolerance ...
The paper discusses recent results on the development of localized arc filament plasma actuators and their use in controlling high-speed and high Reynolds number jet flows. Multiple plasma actuators (up to 8) are controlled using a custom-built 8-channel high-voltage pulsed plasma generator. The plasma generator independently controls pulse repetition rate (0-200 kHz), duty cycle and phase for each individual actuator. Current and voltage measurements demonstrated the power consumption of each actuator to be quite low (20 W at 20% duty cycle). Emission spectroscopy temperature measurements in the pulsed arc filament showed rapid temperature increase over the first 10-20 ?s of arc operation, from below 1000 deg. C to up to about 2000 deg. C. At longer discharge pulse durations, 20-100 ?s, the plasma temperature levels off at approximately 2000 deg. C. Modelling calculations using an unsteady, quasi-one-dimensional arc filament model showed that rapid localized ...
We discuss various reactions at future e"+e"- and #gamma##gamma# colliders involving real (beamstrahlung or backscattered laser) or quasi-real (bremsstrahlung) photons in the initial state and hadrons in the final state. The production of two central jets with large transverse momentum p_T is described in some detail; we give distributions for the rapidity and p_T of the jets as well as the di-jet invariant mass, and discuss the relative importance of various initial state configurations and the uncertainties that arise from the at present rather poor knowledge of the parton content of the photon. We also present results for 'mono-jet' production where one jet goes down a beam pipe, for the production of charm, bottom and top quarks, and for single production of W and Z bosons. Where appropriate, the two-photon processes are compared with annihilation reactions leading to similar ...
We introduce a methodology for analysis of multiwavelength data from X-ray selected BL Lac (XBL) objects detected in the TeV regime. By assuming that the radio--through--X-ray flux from XBLs is nonthermal synchrotron radiation emitted by isotropically-distributed electrons in the randomly oriented magnetic field of a relativistic blazar jet, we obtain the electron spectrum. This spectrum is then used to deduce the synchrotron self-Compton (SSC) spectrum as a function of the Doppler factor, magnetic field, and variability timescale. The variability timescale is used to infer the comoving blob radius from light travel-time arguments, leaving only two parameters. With this approach, we accurately simulate the synchrotron and SSC spectrum of flaring XBLs in the Thomson through Klein-Nishina regimes. Photoabsorption by interactions with internal jet radiation and the intergalactic background light (IBL) is included. Doppler factors, magnetic fields, ...
The Japan Atomic Energy Research Institute has conducted a piping reliability test program to demonstrate the safety and reliability of light water reactor primary piping. In this program, pipe fatigue test, leak-before-break (LBB) verification test and pipe rupture test were carried out to examine the integrity of piping, to verify the LBB and to demonstrate the effectiveness of protective measures against jet impingement and pipe whip loads under a pipe rupture event.In the pipe fatigue test, a procedure to predict the fatigue crack growth was developed, and the integrity of piping during the plant service life was evaluated. In the LBB verification test, the pipe fracture test and the leak rate test were performed to verify the LBB in the primary piping.In the pipe rupture test, the influence of jet impingement on the target disk and the deformation behavior of whipping pipe and restraint were investigated. Using the test results, the ...
We consider the physics and collider phenomenology of quirks that transform nontrivially under QCD color, SU(2)_W as well as an SU(N)_{ic} infracolor group. Our main motivation is to show that the recent Wjj excess observed by CDF naturally arises in quirky models. The basic pattern is that several different quirky states can be produced, some of which beta-decay during or after spin-down, leaving the lightest electrically neutral quirks to hadronize into a meson that subsequently decays into gluon jets. We analyze LEP II, Tevatron, UA2, and electroweak precision constraints, identifying the simplest viable models: scalar quirks ("squirks") transforming as color triplets, SU(2)_W triplets and singlets, all with vanishing hypercharge. We calculate production cross sections, weak decay, spin-down, meson decay rates, and estimate efficiencies. The novel features of our quirky model includes: quirkonium decay proceeds into a pair of gluon jets, ...
Upon request by the Science and Technology Agency of Japanese Government, the Japan Atomic Energy Research Institute has conducted Piping Reliability Test Program to demonstrate the safety and reliability of light water reactor primary pipings. In this report, the results of the program are summarized. In the test program, pipe fatigue tests, Leak-Before-Break (LBB) verification tests and pipe rupture tests were carried out to examine the integrity of pipings, to verify the LBB concept and to demonstrate the effectiveness of the protective measures against jet impingement and pipe whip under pipe rupture event, respectively. In the pipe fatigue tests, a procedure to predict the fatigue crack growth was developed and the integrity of piping during plant service life was demonstrated. In the LBB verification tests, pipe fracture tests and leak rate tests were performed using cracked pipes. Based on the test results, LBB in the primary pipings was demonstrated. In the ...
We intend to solve equations governing turbulent plane-vertical isotherm and non isotherm jets by taking into account inflow conditions at the exit of the nozzle. The analysis is focused on the influence of these conditions on this type of flow. Two cases are considered (uniform and parabolic velocity and temperature profiles). A finite difference scheme is developed to solve the governing equations. This numeric model allows us to show that the region of fully developed regime begins much nearer the nozzle for the turbulent case than for the laminar flow case. Indeed, the turbulence increases the mixing between the incoming gas from the nozzle and the ambient fluid, and consequently the size of the potential core zone decreases. The results are compared to other works introducing mathematical variables based on the energy conservation for the case of the mixed convection and the momentum conservation for the forced convection, which allows the validation of our ...
We have developed a photon accumulated laser mass spectrometer that enables us to identify isomers of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran. This system is comprised of a high temperature (230 deg. C) pulsed gas injector (PGI), multimirror multipath system (MMS), and the conventional time-of-flight mass spectrometer. The PGI induces the formation of a choked supersonic jet gas pulse that cools down to a temperature to restrain fragmentation and reduces vibrational and rotational thermal noises. The results suggest that the excited lifetime numbers and fragment dynamics of these species change completely with jet cooling of molecules. The MMS enhances the soft ionization efficiency (by a factor of 1000 over a single path system) through photon accumulation by extending the irradiation duration (to about 40 ns) and volume, and it further minimizes fragmentation by carefully controlling the laser intensity distribution ...
The objective of the program is to develop a domestic cooktop with low-NOx emissions and high efficiency. During the first two phases of the program, three design concepts were developed, and two versions of developmental prototypes using the IR-Jet approach were fabricated and tested. The third phase was initiated to address the design issues of burner turndown and modulation and to conduct the field test of a prototype with one IR-Jet and three conventional burners. Two prototypes containing one IR-Jet and three conventional burners and utilizing blower speed control for air/gas modulation were fabricated. One unit employed a brushless dc motor and the other a 2-pole ac motor. The ac motor prototype was field tested. Field testing showed the need for a mechanical air/gas valve for modulation and for a 1500 Btu/hr simmer setting. A 4-inch-diameter stepped-tile configuration provided input rates from 1500 to 8000 Btu/hr. A ...
This paper evaluates abrasive jet wear tests, carried out on the ZUK-3M abrasion apparatus according to the GOSF 23.201-78 industrial standard. As abrasive material, brown coal coke dust, brown coal dust, power plant fly ash and quartz sand (for the purpose of comparison) were employed. Seventeen types of materials were blasted with abrasive jets, including a selection of steels, glass, rubber, SYS-pur plastics, cast basalt, Kawenit and vitroceramics. The test apparatus produced abrasive jet velocities between 12 and 130 ms/SUP/-/SUP/1 at rotor revolutions of 1,000 to 10,000 min/SUP/-/SUP/1. Blasted material samples were arranged at angles between 15 and 90 degrees. Various tables and graphs present abrasivity results. These results were employed for technical modifications of dedusting equipment in briquetting and coking plants, which led to a threefold increase in service life of abrasion endangered equipment parts. (8 ...
While feedback is important in theoretical models, we do not really know if it works in reality. Feedback from jets appears to be sufficient to keep the cooling flows in clusters from cooling too much and it may be sufficient to regulate black hole growth in dominant cluster galaxies. Only about 10% of all quasars, however, have powerful radio jets, so jet-related feedback cannot be generic. The outflows could potentially be a more common form of AGN feedback, but measuring mass and energy outflow rates is a challenging task, the main unknown being the location and geometry of the absorbing medium. Using a novel technique, we made first such measurement in NGC 4051 using XMM data and found the mass and energy outflow rates to be 4 to 5 orders of magnitude below those required for efficient feedback. To test whether the outflow velocity in NGC 4051 is unusually low, we compared the ratio of outflow velocity to escape ...
The TRIGA-SPEC experiment has been installed recently at the research reactor TRIGA Mainz. Ground state properties like masses, charge radii, spins, and moments of short-lived nuclides can be determined with very-high precision using the Penning trap mass spectrometer TRIGA-TRAP, and the collinear laser spectroscopy setup TRIGA-LASER. Short-lived neutron-rich radionuclides in the mass range 80 < A < 140 are produced by thermal neutron induced fission of e.g. U-235, Pu-239 or Cf-249, respectively. For the extraction and ionization of the fission products a gas-jet system is coupled to a 2.45-GHz ECR ion source for the production of singly charged ions. The gas-jet has been tested on-line and fission products have been extracted. First off-line tests of the ion source have been performed successfully with argon gas. The results of the commissioning test of the ion source and the on-line coupling of the experiments are presented.
We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5-10 keV) and six VLA/EVLA (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; This builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of L_radio proportional to L_X-ray ^(-0.72+/-0.04) . Current research linking the mass of supermassive black holes and stellar-mass black holes in the "low/hard" state to X-ray luminosities and radio luminosities suggest a "fundamental plane of accretion onto black holes" that has a positive correlation of L_radio proportional to L_X-ray^(0.67+/-0.12) . Our simultaneous results differ from this relation by more than 11 sigma, indicating that a separate mode of accretion and ...
The Fermi National Laboratory (Fermilab) operates the Tevatron proton-antiproton collider at a center-of-mass energy of {radical}s = 1.96 TeV, the is therefore the only collider which is today able to produce the heaviest known particle, the top quark. The top quark was discovered at the Tevatron by the CDF and D0 collaborations in 1995. At the Tevatron, most top quarks are produced via the strong interaction, whereby quark-antiquark annihilation dominates with 85%, and gluon fusion contributes with 15%. Considering next-to-leading order (NLO) contributions in the cross section of top-antitop quark production, leads to a slight positive asymmetry in the differential distribution of the production angle {alpha} of the top quarks. This asymmetry is due to the interference of certain NLO contributions. The charge asymmetry A in the cosine of {alpha} is predicted [14] to amount to 4-6%. Information about the partonic rest frame, necessary for a measurement of A in the observable cos ...
Gadolinium nitrate has been employed in Indian nuclear reactors for the first time as soluble neutron poison in the heavy water moderators of the 540 MWe PHWRs TAPS 3 and 4, as a fast acting secondary shut down system (SDS-2); and also for reactivity shim. For this purpose, the moderator purification system is currently equipped with special ion-exchange columns/schemes, developed by present authors. However, for gadolinium removal from moderator in the post SDS-2 scenario, the two stage ion-exchange - cation bed operation followed by mixed bed operation - results in low pH conditions persisting in the moderator for a few hours, which gives rise to certain operational problems. The present paper describes a mixed bed ion-exchange scheme employing macro-porous strong acid cation and macro-porous weak base anion resins, which has been developed to eliminate acidic conditions and gives a better pH control. The cation to anion ...
Progress reports are presented for the following two areas: catalytic cracking studies with water-wet silica-alumina catalysts; and Fischer-Tropsch reactor studies where similarities and differences between fixed bed and slurry type reactors are investigated and further experiments conducted to measure mass transfer coefficients and reaction kinetics which are to be used in a model slurry reactor. The following are some of the conclusions. (1) The premise that the presence of liquid water might increase catalytic cracking activity was found to be invalid. It was demonstrated that cracking can occur at previously unobserved low temperatures (though at low conversions) and that an anomaly exists in that one of the catalysts tested shows an entirely different cracking behavior and probably follows a different cracking mechanism. (2) the diameter of a fixed-bed Fischer-Tropsch reactor critically affected the resistance of the reactor to plugging ...
We examined the spectral behaviors of lasing from a asymmetrically deformed liquid jet (a ? 14 ?m) which is induced by a laterally flowing gas. Th liquid sample was methanols which contains DCM dye. When n distortion is induced, the lasing spectrum appears as two periodic peaks which are corresponding to the resonance modes of cylindrical cavity. As the distortion parameter exceeds about 4%, the lasing spectrum shifts continuously to short wavelength. When the distortion parameter reaches ? 10%, the amount of blue shift was ? 30 nm. The blue shift can be explained as the shift of optimum wavelength of threshold curves. From the absorption and fluorescence curve of liquid sample, we estimated the spoiled Q with the distortion parameter.
We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p?=?0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p?0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure. PMID:21961652
The spatial distribution of argon clusters in gas jet is tested using the Rayleigh scattering method. A pulsed laser is used to acquire the whole evolution of the cluster inside one event. The measured results at a fixed axial position show that the argon clusters grow in less than one millisecond after the nozzle is opened and the cluster size keeps constant during the whole open period of 20 ms. Further results show that the scattering signal along the radial direction is almost Gaussian-distributed and the full width half maximum (FWHM) increases almost linearly when the distance from nozzle increases. The scattering signal along the axial direction is Landau-distributed and the area near the nozzle is most effective for laser cluster interaction. (authors)
We present the design of a diagnostic system to measure electron cyclotron absorption at the second harmonic E-mode resonance in the JET pumped divertor plasma. The diagnostic will measure transmission as a function of frequency along one or more sightlines from which the spatial profile of the n_eT_e product will be deduced. The divertor is briefly described, and the electron cyclotron resonance physics relevant to this measurement is reviewed. The problems of measuring transmission using an oversized transmission system are discussed and the chosen measurement technique, a swept frequency interferometer using a coherent radiation source, is described. A prototype of the instrument has been assembled to test the measurement technique. Some data demonstrating the instrument's characteristics are presented. The nonresonant losses, which may affect the interpretation of the measurement, are also discussed. (orig.).
Jet-driven shocks are responsible for an important fraction of the emission of the narrow-line regions (NLRs) in many classes of AGN. However, this cannot explain all observations. It is clear that the remaining sources are photoionised by the active nucleus. The 2-d hydrodynamic models from the RSAA group support an evolutionary scenario whereby the shock-excited NLRs are initially jet-driven but later, ionizing photons from the central engine replace shocks as the main excitation mechanism and shock induced star formation may also become important. In their photoionized phase, dusty and radiation-pressure dominated evolution produces a self-regulated NLR spectrum. This model aso explains the coronal emission lines and fast (3000 km s$^{-1}$) outflows seen in some Seyferts.
Morphology of castellated Be tiles from the belt limiter exposed to the JET plasma for 56,000 s was examined on both sides of castellated grooves, on plasma-facing and side surfaces of the tiles. The essential results are (i) deuterium retention in the castellated grooves and in other locations is associated with co-deposition of carbon; (ii) the decay length of deposition in the castellation is around 1.5 mm; (iii) no deuterium is detected in bulk Be; (iv) bridging of gaps by molten beryllium occurred but gaps were not filled with Be; (v) on side surfaces of the tiles the formation of BeO layer was detected at a distance of 20 mm and more from the plasma-facing surface. The consequences for a long-term operation of a reactor-class device with several different plasma-facing materials are addressed.
Strut lattice structures of reaction-bonded silicon infiltrated silicon carbide ceramics (RB-SiSiC) for air-fuel mixture formation and for nonstationary lean-burn under pressure applications were fabricated. The lattice design with a high porosity >80% was shaped by indirect three-dimensional printing. It was shown that pre-ignition processes in the porous reactor are much faster than in a free combustion, especially at lower temperatures. Interaction of high velocity diesel jets with cylindrical strut ligaments of the SiSiC lattice structure offers a new possibility for quick and efficient fuel distribution (multi-jet splitting) in space.
During helium beam fuelling experiments in JET, distinctive anisotropic features have been observed in the velocity distribution function describing both fast and thermal alpha particle populations. During the initial fuelling phase the central helium ion temperature observed perpendicular to the magnetic field is higher than the central electron temperature, while the central helium ion temperature observed parallel to the magnetic field is lower than or equal to the central electron temperature. In order to verify temperature measurements of both perpendicular and parallel lines of sight, other independent methods of deducing the ion temperature are investigated: deuterium ion temperature, deuterium density, comparison with neutron rates and profiles (influence of a possible metastable population of helium). 6 refs., 7 figs.
Erosion-corrosion (E-C) of 3003 aluminum (Al) alloy in ethylene glycol-water solutions were studied by weight-loss and electrochemical measurements as well as surface characterization through an impingement jet system. Al alloy E-C is dominated by erosion components, i.e., pure erosion and corrosion-enhanced erosion, which account for 92-97% of the total E-C rate under the various conditions in this work. Contribution from corrosion components, including pure corrosion and erosion-enhanced corrosion, is slight. With the increase of fluid flow velocity and sand concentration, the total E-C rate increases. Compared with the significant increase of the rates of erosion components, the increase of the rate of corrosion component is negligible. Upon fluid flow, passivity of Al alloy that develo...
This paper presents the experimental results of heat transfer augmentation in an axisymmetric jet impinging normally on a flat plate surface without the requirement of additional pumping power. The present technique of augmentation utilizes only a punched plate with circular holes arranged in a triangular array, fixed parallel to, just in front of the heated target plate. Near the optimum conditions determined, the heat transfer coefficient at the geometrical stagnation point can be increased 4 times. Additional flow visualization study indicates that this augmentation mechanism creates an improved flow field where the punched plate acts as a detached fin, the conductivity of which may be exploited for further augmentation. Besides augmentation, the present investigation foresees the possibility of manipulating the distribution of local heat transfer rate by varying few parameters.
Abstract To investigate the link between the functionality and the diversity of microbial communities under strong selective pressure from pollutants, two types of mesocosms that simulate natural attenuation and phytoremediation were generated using soil from a site highly contaminated with jet fuel and under air-sparging treatment. An increase in the petroleum hydrocarbon concentration from 4900 to 18-500-mg-kg-1-dw soil simulated a pollutant rebound (postremediation pollutant reversal due to residual contamination). Analysis of soil bacterial communities by denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments showed stronger changes and selection for a phylogenetically diverse microbial population in the mesocosms with pollutant-tolerant willow trees. Enumerat...
Recently several investigators reported on various means of generating cold plasma jets at atmospheric pressure. More interestingly, these jets turned out to be not continuous plasmas but trains of small high velocity plasma packets/bullets. However, until now little is known of the nature of these 'bullets'. Here we present experimental insights into the physical and chemical characteristics of bullets. We show that their time of initiation, their velocity and the distance they travel are directly dependent on the value of the applied voltage. We also show that these bullets can be controlled by the application of an external electric field. Using an intensified charge coupled device camera we report on their geometrical shape, which was revealed to be 'donut' shaped, therefore giving an indication that solitary surface ionization waves may be responsible for the creation of these bullets. In addition, using emission spectroscopy, we follow ...
The alpha-particle confinement of future D-T experiments at JET can be severely degraded by Global Alfven Eigenmodes (AE). Scenarios for the excitation of Alfven Eigenmodes in usual (e.g. D-D) plasmas are proposed, which provide a MHD diagnostic and allow the study of the transport of super-Alfvenic ions. Active studies with separate control of TAE amplitude and energetic particle destabilization, measuring the plasma response, give more information than passive studies, in particular concerning the damping mechanisms. The TAE excitation can be achieved by means of the saddle coil and the ICRH antenna. The experimental method is introduced together with a theoretical model for RF excitation. (authors). 6 refs., 3 figs.
Disclosed is a gas-fired cooktop for a range which provides high thermal efficiency and low emissions of air pollutants, particularly low levels of NO{sub x}. The cooktop includes a perforated tile burner which radiates infrared energy upward at a high flux rate to rapidly quench burner gas temperatures and inhibit the formation of NO{sub x}. A perforated glass-ceramic jet plate positioned between the burner and a cooking vessel transmits most of the radiant infrared energy from the burner to the vessel and also forms jets of combustion products which are directed against the bottom of the vessel fo convective heating. Thermal efficiencies of up to about 70% and NO{sub x} emissions as low as about 15ppM are achieved by the cooktop.
Experiments of plasma nitriding of titanium are carried out by two plasma sources. One is a microwave discharge plasma source under several Torr, and the other is a nitrogen arc jet generated under atmospheric pressure followed by rapid expansion into a gas wind tunnel. The relationship between the surface density of nitrogen atoms in the #alpha#-Ti and various plasma parameters is systematically studied. For the microwave nitrogen plasma, it is found that the effect of the vibration temperature is the most essential for the surface nitriding, whereas the effect of electron temperature, density and rotation temperature is less remarkable. It is also found that the higher vibration temperature of the microwave discharge nitrogen plasma makes the target temperature higher, and consequently, the surface density of atomic nitrogen remarkably increased. However, the effect of target temperature is less remarkable for the arc jet nitrogen plasma.
The effect of high lift airfoils on the cost effectiveness of HAWT and VAWT (horizontal and vertical axis wind turbine) machines is studied. The scope involved first studying modern two dimensional airfoils, and developing a generalized formulation for their performance in terms of lift, drag, and thickness at appropriate Reynolds numbers. Single element, multi-element, symmetrical, extra thick airfoils and jet flap airfoils were analyzed. The jet flap airfoils were considered to be unacceptable because of excessive power requirements. Then the effect of using the above airfoils on the rotors of a variety of wind turbines was made. Qualitative representation of the type of airfoils studied is given.
A particle-laden turbulent reacting flow model is described and applied to in-furnace, dry SO_2 control in boilers. Sulfur capture by calcium-based sorbents is represented by a shrinking core model which accounts for surface areas loss and product layer diffusion. Sorbent particle trajectories and dispersion are followed with cloud statistics in a Lagrangian framework. The turbulent fluid mechanics and chemical reactions are coupled, and solutions obtained for mean and fluctuating velocity, composition, and particle position. Comparisons are made with data from an US EPA laboratory reactor. Practical implications for SO_2 control are examined including the effects of jet velocity, sorbent injection location, boiler load and thermal profiles.
Abstract Localized regions of enhanced emission from HCO+, NH3 and other species near Herbig-Haro objects (HHOs) have been interpreted as arising in a photochemistry stimulated by the HHO radiation on high-density quiescent clumps in molecular clouds. Static models of this process have been successful in accounting for the variety of molecular species arising ahead of the jet; however, recent observations show that the enhanced molecular emission is widespread along the jet as well as ahead. Hence, a realistic model must take into account the movement of the radiation field past the clump. It was previously unclear as to whether the short interaction time between the clump and the HHO in a moving source model would allow molecules such as HCO+ to reach high enough levels, and to survive fo...
Blowdown thrust forces and decompression characteristics were evaluated concerning the jet discharge or pipe whip tests with a 4-inch or 6-inch diameter pipe under PWR LOCA or BWR LOCA conditions related to pipe rupture accidents in nuclear power plants. This paper presents experimental evaluations of time-dependent and maximum blowdown thrust forces, and evaluations of decompression characteristics under instantaneous pipe rupture conditions. The following items are discussed: the peak value of the blowdown thrust force, the jet thrust coefficient for the maximum blowdown thrust force, the pressure recovery after break, and the relationship between the pressure undershoot of the sudden decompression and the decompression rate.
Full text: Institute for Nuclear Research, Pitesti-Mioveni, Romania in direct cooperation with the National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest studied and prepared for coating more than 1000 tiles made of Inconel with 7-9 #mu#m of beryllium for nuclear fusion applications at JET, Culham, UK. The principles of manufacturing processes using thermal evaporation and plasma ignited in pure metal vapors as well as by Thermionic Vacuum Arc (TVA) method and the properties of the Ni and Be coatings are presented. The prepared beryllium layers were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. (authors)
The purpose of pipe rupture studies in JAERI is to perform model tests on pipe whip, restraint behavior, jet impingement and jet thrust force, and to establish a computational method for analyzing these phenomena. This report presents the analytical results of 4-inch pipe whip tests under BWR LOCA conditions. Dynamic response analyses were performed using the general-purpose finite element program ADINA. The test pipe was modelled by straight beam elements and the four restraints were modelled by a single truss element. The analytical results were compared with the experimental results. Impact time and maximum total restraint force showed good agreement with experimental results. On the other hand, pipe strain and pipe deflection could not be predicted so well. The reason for this is that the sliding of the restraint during the pipe whip movement cannot be considered in the analyses.
Catalyst deactivation during steam reforming of transportation fuels, primarily due to sulfur poisoning and carbon deposition, is a major hurdle in the commercialization of fuel cell technologies. In an attempt to better understand the phenomena, a previously formulated multi-component (Ni, Pd, Rh) catalyst supported on g-Al2O3 was studied under steam reforming of Jet A spiked with thiophene to achieve a total sulfur content of 1000ppm by weight. Analysis of fresh catalysts showed the presence of two groups of active metal particles, primarily distinguished by their size and composition; small particles (1-5nm) largely comprised of Rh and large particles (10-20nm) that were predominantly Ni, with or without the presence of Pd. Analysis of used catalysts showed sintering of crystallites con...
Human beings are confronted with another grievous disaster - coal fire. The monitoring on underground coal bed combustion relied on drilling supervising in the past, but this method is not good. By taking the coal fire of Gulaben mine in Inner Mongolia Autonomous Region as an example, the monitoring methods of underground coal bed combustion were explored based on the hyperspectra and high-resolution remote sensing technology. By employing the OMIS imaging apparatus developed by Shanghai Institute of Technical Physics of Chinese Academy of Sciences, the airborne hyperspectral images and the characteristic spectra of different types were obtained and the temperature was measured synchronously on the ground. Then according to the correlation of DN value of the thermal infrared band and surface temperature, the image information was processed, the spectral features were analyzed, and the surface temperature retrieval model was built. Finally, by ...
This work presents comparative results of a numerical investigation of four possible models for the prediction of thermal performance of fixed bed storage units and their thermal design. These models includes Schumann's model, the radial dispersion model, a model that include both axial heat conduction in the fluid phase and admits thermal gradient in the solids particles and finally a two dimensional single phase model. For each of these models a computer code was written and tested to evaluate the computing time of same data and analyze any other computational problems. The tests of thermal performance included particle size, porosity, particle material, flow rate, inlet temperature and heat losses form tank walls and extremities. Dynamics behaviour of the storage units due to transient variation in either flow rate or inlet temperature was also investigated. The results presented include temperature gradients, pressure drop and heat storage. The results ...
We have investigated and modeled the boron diffusion in silicon following ultra-low-energy implantation (500 eV). It is well known that reducing implant energies is an effective way to eliminate transient enhanced diffusion due to the excess of interstitials from the implant. However, for sub-keV B implants diffusion remains enhanced. This enhancement is linked to the presence of a silicon boride layer located at the silicon surface which creates interstitials. This phenomenon is named 'boron enhanced diffusion' (BED). The BED effect is of obvious interest since it counteracts the advantage obtained by reducing the ion implantation energy. For these reasons, we have investigated the diffusion of low-energy boron implanted in crystalline silicon and tested a complete simulation program, which takes into account the effect of boron precipitation and the effect of the silicon boride layer as a source of self-interstitials. ...
A three-dimensional mathematical model has been developed as a tool for furnace structure design and operation conditions optimization when the straw combustion is in oxygen-enriched or conventional air atmospheres. Mathematical methods have been used based on a combination of FLIC (A fluid Dynamic Incinerator Code) code for the in-bed incineration and commercial software FLUENT for the over-bed combustion. Oxygen-enriched atmospheres promote the destruction of most pollutants due to the high oxygen partial pressures and temperatures, which is reflected by very low residual amounts of organic combustion by-products in the bottom ash and flue gas of the straw-fired boiler unit. The predictions indicated that the maximum combustion temperature is around 1500 K, CO emission is 201 vppm and O{sub 2} concentration is about 6.9 vol% at furnace exit, and it is shown that mathematical models can serve as a reliable tool for detailed analysis of straw ...
During the water detritiation process most of the tritium inventory is transferred from water into the gaseous phase, then it is further enriched and finally extracted and safely stored. The control of tritium inventory is an acute issue from several points of view: - Financially - tritium is an expensive material; - Safeguard - tritium is considered as nuclear material of strategic importance; - Safety - tritium is a radioactive material: requirements for documented safety analysis report (to ensure strict limits on the total tritium allowed) and for evaluation of accident consequences associated with that inventory. Large amounts of tritium can be stored, in a very safely manner, as metal tritides. A bench-scale experiment of a tritium storage bed with integrated system for in-situ tritium inventory accountancy was designed and developed at ICSI Rm. Valcea. The calibration curve and the detection limit for this experimental model of tritium storage ...
The present study numerically investigates the enhancement of forced convective heat transfer from a single circular cylinder embedded in a packed bed of spherical particles confined by two impermeable parallel plates. The heat transfer results from the heated cylinder, with and without the presence of a porous medium, are compared. The results show that the presence of the porous particles enhances the heat transfer from the cylinder; however, the significant heat transfer augmentation is produced at high Re due to the effect of thermal dispersion. In addition, the effect of Re on Nut is much greater than that of kr and Bi in the porous channel. It is also found that the %?p is much higher than %HTE producing from packing the empty channel.
The evaluation methodology utilized in deciding to change over Oyster Creek plant operation from chemical regeneration of condensate demineralizer resin beds to throwaway of this spent resin is presented. Both the economic and operational aspects considered are discussed. The evaluation shows that potential savings in the $1.1M range are feasible over a 5 year cycle. Cost sensitivity analysis results define the throwaway versus regeneration breakeven point to be 47 condensate demineralization beds per 5 year cycle. The evaluation also discusses the trade off between resin and evaporator concentrates burial volumes. Analyses are given which show that the burial volume cost equivalency of resin to solidified concentrates is 150 ft./sup 3/ of resin equals 400 ft./sup 3/ of concentrates. Based on one year of power operation in the throwaway mode, the savings and operational value anticipated in the initial study are being realized.
The design of solid breeder blankets is strongly affected by the low values of thermal conductivity and density of ceramic breeder pebble beds. A significant rise of both quantities would enhance the thermal performance and lead to an increased tritium breeding ratio. In order to improve these quantities pretreated lithium orthosilicate pebble material was dry pressed and subsequently sintered. The thermal conductivity of cylindrical pellets was determined by the heat pulse method using a laser flash device. A pebble bed characteristic sample was also investigated in order to check the measurement accuracy in comparison with previous results. Furthermore, two samples of low density cellular ceramics were also prepared by infiltration of polymer foams with a ceramic slurry. The thermal cond...
Two cases of tetracycline ulcers of the oesophagus are reported and compared with thirteen other cases from the literature. In most cases, the patients had taken their capsules with little or no fluid just before going to bed. Some hours later they developed retrosternal pain that was intensified by swallowing. Endoscopy showed sharply demarcated greyish-white areas of mucosal damage which represented layers of stratified squamous cells, separated by oedema, and a dense neutrophilic infiltration of the lamina propria and the muscularis mucosa. Roentgenology was unsuitable to detect the lesions. They healed without complications within one to six weeks. Prolonged retention of the capsules in the oesophagus is thought to cause the mucosal damage. Patients on oral tetracycline or doxycycline treatment should therefore be instructed to take their capsules with a meal or with copious water and not just before going to bed.
In vulnerable individuals, exposure to stressors can result in chronic disorders such as generalized anxiety disorder (GAD), major depressive disorder (MDD), and post-traumatic stress disorder (PTSD). The extended amygdala is critically implicated in mediating acute and chronic stress responsivity and anxiety-like behaviors. The bed nucleus of the stria terminalis (BNST), a subregion of the extended amygdala, serves as a relay of corticolimbic information to the paraventricular nucleus of the hypothalamus (PVN) to directly influence the stress response. To investigate the influence of the corticosteroid milieu and housing conditions on BNST function, adult C57Bl/6J were either acutely or chronically administered corticosterone (CORT, 25mg/kg in sesame oil) or vehicle (sesame oil) or were g...
Sandia National Laboratories has erected a research oriented, 34- meter diameter, Darrieus vertical axis wind turbine near Bushland, Texas. This machine, designated the Sandia 34-m VAWT Test Bed, is equipped with a large array of strain gauges that have been placed at critical positions about the blades. This manuscript details a series of four-point bend experiments that were conducted to validate the output of the blade strain gauge circuits. The output of a particular gauge circuit is validated by comparing its output to equivalent gauge circuits (in this stress state) and to theoretical predictions. With only a few exceptions, the difference between measured and predicted strain values for a gauge circuit was found to be of the order of the estimated repeatability for the measurement system.
In this paper Particle Bed Reactor (PBR) designs are discussed which use /sup 233/U and /sup 242m/Am as fissile materials. A constant total power of 100MW is assumed for all reactors in this study. Three broad aspects of these reactors is discussed. First, possible reactor designs are developed, second physics calculations are outlined and discussed and third mass estimates of the various candidates reactors are made. It is concluded that reactors with a specific mass of 1 kg/MW can be envisioned of /sup 233/U is used and approximately a quarter of this value can be achieved if /sup 242m/Am is used. If this power level is increased by increasing the power density lower specific mass values are achievable. The limit will be determined by uncertainties in the thermal-hydraulic analysis. 5 refs., 5 figs., 6 tabs.
A flowing bed kiln is a gas-solid reactor used in the civil nuclear fuel cycle for the successive conversion of uranium trioxide (UO{sub 3}) into uranium dioxide (UO{sub 2}) and then into uranium tetrafluoride (UF{sub 4}). A numerical model is developed which simulate the behaviour of this reactor in permanent regime. This model describes the physico-chemical phenomena involved, and combines a mechanistic approach in the vertical area of the kiln (resolution by the finite volumes method) and a systemic approach in the horizontal area, like in the model of cascade mixers. The first results have been obtained for reference operating conditions of the industrial kiln. Some possible improvements of the optimum temperature progression inside the kiln are evoked. (J.S.)
Formulas were developed based on an aqueous solution of hydrolyzed polyacrylonitrile widely used in the oil industry. The additive used consisted of products of industrial production: synthetic resin TEG-1 with hardening agent PEPA (polyehtylene polyamine) and technical formalin. The mixtures containing about 80-85% by volume 5% hydrolyzed polyacrylonitrile, 10-15% by volume of resin TEG-1 with hardening agent PEPA and 3-5% by volume formalin satisfy the requirements made for the plugging materials. The initial mixtures are distinguished by technological efficiency of preparation and have controllable hardening periods. Physical-chemical properties are given for the gel polymers. In the set of properties, the mixtures based on hydrolyzed polyacrylonitrile, resin TEG-1 with hardening agent PEPA and formalin can be recommended as plugging materials of temporary action with complex treatment of the heterogeneous beds.
The effect of mean daily air temperature (MDT) on flowering rate (the reciprocal of days to flower) was quantified for 18 species of annual bedding plants. Plants were grown in environmental growth chambers at constant air temperature set points of 5, 7.5, 10, 15, 25, or 30^oC and under an irradiance of 160-180mmolm^-^2s^-^1, with a 16-h photoperiod. Nonlinear mathematical equations were developed to predict the effect of MDT on flowering rate and to estimate the base, optimum, and maximum temperatures (Tmin, Topt, and Tmax), which are the temperatures at which flowering rates are zero (low temperature), maximal, and zero once again (high temperature), respectively. The estimated Tmin varied among species and ranged from 1.1^oC in French marigold (Tagetes patula L.) to 9.9^oC in angelonia ...
An emergency shutdown system for high-temperature gas-cooled pebble-bed reactors is proposed in addition to the common absorber rod shutdown system. This system is based on the strongly absorbing effect of small boronated graphite spheres (called KLAK), which trickle in case of emergency by gravity from the top reflector into the reactor core. The inner reflector of the Siemens-Argonaut reactor was substituted by an assembly of spherical Arbeitsgemeinschaft Versuchsreaktor fuel elements, and the shutdown effect was examined by installing well-defined KLAK nests inside this assembly. The purpose was to develop and prove a calculational procedure for determining criticality values for assemblies of large fuel spheres and small absorbing spheres.
The effect of the coated composite surface of particles on the mechanical properties of the powder bed was investigated. Polyethylene-silica surface composite powder was prepared at several coating ratios with Hybridizer. Various tests on mechanical properties of the powder bed were carried out with the prepared powder, and the following results were obtained: The ultimate tensile strength depends only on the cohesive force between particles, and the contact probability model of composite particles led to good agreement between the experimental and calculated values. The coefficient of internal friction and cohesive shear strength were influenced due to the interlocking effect of the surface roughness of composite particles. The effects of coating particles became small with dynamic properties like angle of repose. It is possible to control the mechanical properties in a step wise fashion by changing the coating ratio of the particles. 10 ...
A numerical model for the development of bed dominated scour around sub-sea structures is presented. The hydrodynamic part of the model is based on a modified potential flow theory. The purpose of the present study has been to develop relatively simple models, yet complex enough to capture the main physics that can be used as engineering tools. An overview of scour phenomena and the basic problems of scour in steady current flow is presented. A hydrodynamic model for horseshoe vortex is presented, as well as a model for the bed transport, and examples are given. The scour in oscillatory flow and a curvilinear model for suspended sediment calculations are described. An advection-diffusion model (formulated in a curvilinear stretched coordinate system) has been developed and is described in an article which has been submitted for publication, a copy of the article is enclosed in Appendix E of the report. (EG)
Fur die Trennung binarer Gemische wird zunehmend das Simulated Moving Bed (SMB)-Verfahren verwendet. Fur einen storungsfreien Betrieb mussen die Volumenstrome sowie die Umschaltzeit exakt eingestellt werden. In diesem Beitrag wird mit Hilfe des Coherence-Konzepts eine Methode aufgezeigt, mit der sich die Stellgroen fur einen dispersionsfreien SMB-Prozess bestimmen lassen. Fur Langmuir- und Anti-Langmuir-Isotherme konnen einfache explizite Gleichungen bei vollstandiger Trennung angegeben werden. Das Grundprinzip dieser Methode lasst sich auch auf andere Isotherme sowie fur die unvollstandige Trennung ubertragen.
The moment analysis of pulse responses was applied to a biological activated carbon (BAC) bed to evaluate the microbial activity. Glucose and activated carbon fiber (ACF) were employed in experiments as a model tracer and an activated carbon respectively. No significant difference in biodegradation rates of glucose by microorganisms attached on different solid supports such as activated carbon inactivated carbon and glass fibers was observed. However, higher microbial activity was obtained from microorganisms supported on the ACF in terms of the apparent degradation of total organic including metabolic byproducts by microorganisms, since part of the metabolic byproducts was irreversibly deposited onto the ACF. 11 refs., 6 figs.
Decontamination and decommission activities related to the Molten Salt Reactor Experiment (MSRE) involve the trapping and recovery of radiolitically generated uranium hexafluoride and fluorine. Although fission product radiolysis was known to generate F{sub 2}, the formation of UF{sub 6} and its transport from the fuel salt was unexpected. Some of these gaseous radiolysis products have been moving through the gas piping to a charcoal bed since the reactor was shut down in 1969. Current and planned remediation and clean-up activities involve the trapping of the gaseous products, deactivation and treatment of the activated charcoal bed, stabilization and reconditioning of the fuel salt, and recovery of the uranium. The chemical aspects of these processes, including radiolytic generation mechanisms, reactions between uranium hexafluoride and fluorine and trapping materials such as activated charcoal, activated alumina, and sodium fluoride, along ...
Abstract Aims: To develop an in vitro flat-bed perfusion biofilm model that could be used to determine the antimicrobial efficacy of topically applied treatments. Methods and Results: Pseudomonas aeruginosa and Staphylococcus aureus biofilms were grown within continuously perfused cellulose matrices. Enumeration of the biofilm density and eluate was performed at various sampling times, enabling determination of the biofilm growth rate. Two antimicrobial wound dressings were applied to the surface of mature biofilms and periodically sampled. To enable real-time imaging of biofilm growth and potential antimicrobial kinetics, a bioluminescent Ps. aeruginosa biofilm was monitored using low-light photometry. Target species produced reproducible steady-state biofilms at a density of c. 107 per b...
A study conducted at the IHS had the aim to obtain basic information on whether it is possible to build flow turbines following the free jet principle that are on a par with, or superior to, the conventional design, especially in terms of performance and the efficiency curve. Several inflow contours with a ventilated free jet and a conventional flow turbine were studied. The direct comparison of these variants revealed a slightly enhanced peak load efficiency and a very distinct superiority of the free jet contour during partial load. But the efficiency of all variants failed to attain the values claimed by commercial manufacturers. As compared to the initial contour, peak load efficiency was enhanced by 5 per cent. During partial load, the variants studied showed a distinct superiority of the free jet concept over the contour of conventional flow turbines. (orig.) [Deutsch] Am IHS wurde eine ...
Suspension direct current plasma spraying allows achieving finely structured coatings whose thickness is between few tens and few hundreds of micrometres. Drops (200-300 ?m in diameter) or liquid jets are mechanically injected in the plasma jet. With radial injection they are rapidly (a few ?s) fragmented into droplets (a few ?m in diameter). The latter are vaporized (in a few ?s) and the solid particles contained in suspension droplets are accelerated and melted by the plasma jet. As in conventional plasma spraying (CPS), much smaller splats (with diameters between 0.2 and 3 ?m and thicknesses between 30 and 200 nm) are arranged in layers up to form the coating. The low inertia of particles requires spray distances between 40 and 60 mm which induces plasma heat fluxes up to 22 MW m-2 participating in coating densification. Even more than in CPS, the plasma jet fluctuations, particularly for plasmas ...
... Targeted fields of research Continuation of ongoing research - Finalising detailed design work on the ITER project; getting JET operational at full power; Improvement of the basic concepts of fusion devices - Fusion plasmas; theoretical studies; technology watch on research into inertial confinement; new experimental concepts and systems; etc.; Long-term technology - Preparations for building a demonstration reactor (development of tritium breeding blankets; prospective ...
A numerical method for studying the flow field of an under-expanded axis-symmetric jet created by a converging-diverging nozzle and impinging on a flat plate is presented. The calculation domain of interest is a region that contains all the features of the jet that leaves the nozzle and impinges onto the plate. Axial symmetry of the domain allows a reduced 2-dimensional model to be used. FLUENT software is utilized to solve the continuity, momentum and energy equations using a coupled implicit scheme. The ideal-gas law is used to determine the gas density along with a k-#epsilon# turbulence model with a special modification to account for compressibility effects. In addition, the temperature dependency of viscosity has been taken into consideration. A number of different modeling techniques are investigated including different approximations to account for the flow inside the nozzle. Performance of non-equilibrium wall functions for near-wall ...
High pressure experiments in a jet-stirred reactor have been performed to study the NO{sub x} formation in lean premixed combustion of methane/air mixtures. The experimental results are compared with numerical predictions using four well known reaction mechanisms and a model which consists of a series of two perfectly stirred reactors and a plug flow reactor. (author) 2 figs., 7 refs.
An improved hydrocarbon fuel is described selected from the group consisting of gasoline, diesel fuel, kerosene, jet fuel, No. 1 heating oil, and No. 2 heating oil containing a detectable amount of one or more fullerene additives therein serving as identification means for said fuel wherein said fullerenes are present in an amount insufficient to alter any of the combustion properties of the fuel.
Observations are presented that link extratropical Rossby wave disturbances excited in the Southern Hemisphere subtropical jet to the initiation of convectively coupled Kelvin waves in the Pacific intertropical convergence zone (ITCZ) during austral winter. A baroclinic, zonal wavenumber 6, eastward-propagating Rossby wave train in the subtropical jet turns northeastward in the vicinity of Australia, inducing upper tropospheric divergence and vertical motion fields that spread equatorward and induce cloudiness anomalies in the Tropics. Lower tropospheric pressure surges excited from the extratropics also induce Kelvin wave-like geopotential height and temperature anomalies at the surface, providing additional lower tropospheric convergence and vertical motion forcing. The tropical outgoing longwave radiation (OLR) and circulation fields propagate eastward in tandem with the extratropical Rossby wave train at approximately 17 m s-1. Kelvin wave ...
In this paper, the turbulence structures of premixed impinging jets are investigated by three different experimental techniques: time-resolved particle image velocimetry (TPIV) visualisation, hot wire anemometry (HWA) and acoustic signal processing. The focus is on the TPIV, with the other two techniques providing supplementary information. The 2-D velocities of the impinging jets were obtained by TPIV. The contour maps of velocity derivatives were computed to facilitate the visualisation of the turbulence structure of the reactant part of turbulent impinging flames. Particular attention was concentrated on the turbulence structures out of the burner nozzle and their interactions with the combustion process. It was found that the contour plots are effective in visualising time-dependent structures. It is demonstrated that the derivatives of the velocity field are able to reveal many otherwise hidden turbulence patterns. Test cases were designed ...
The authors synthesized a number of esters of stearic acid with polyhydric alcohols and ran comparative tests on aliphatic alcohols to determine their effects on the antiwear properties of the fuel. They conclude that the differences in effectiveness in improving the lubricity by the use of aliphatic alcohols and the full and partial esters of polyhydric alcohols and stearic acid can be explained by the presence of hydroxyl and ester groups close to each other in partial esters. This is reflected in the higher polarity of the partial esters, a higher rate of adsorption, and a stronger bonding of the adsorbed layer to the metal surface.
The objective of the program is to develop a domestic cooktop with low NOx emissions and higher efficiency. During the first phase of the program, a developmental prototype incorporating four IR-Jet burners was assembled. The report describes the work performed during the second phase of the program and covers optimization, and testing of the developmental prototype and design, fabrication and testing of the field-test prototype.
This standard addresses the design bases for light water reactor, nuclear power plant structures and components essential for the protection of public health and safety from the potential adverse effects of pipe whip, jet impingement, pressurization of compartments outside containment, environmental conditions and flooding associated with a postulated pipe rupture. The design bases for missile protection and the design bases for containment pressurization are not within this standard.
Plans for the disposal of radioactive liquid and solid wastes presently stored in double-shell tanks at the Hanford Site call for retrieval and processing of the waste to create forms suitable for permanent disposal. Waste will be retrieved from a tank using a submerged slurry pump in conjunction with one or more rotating slurry jet mixer pumps. Pacific Northwest Laboratory (PNL) has conducted tests using simulated waste slurries to assess the effects of a impinging slurry jet on the corrosion rate of the tank wall and floor, an action that could potentially compromise the tank's structural integrity. Corrosion processes were investigated on a laboratory scale with a simulated neutralized cladding removal waste (NCRW) slurry and in a subsequent test with simulated neutralized current acid waste (NCAW) slurry. The test slurries simulated the actual NCRW and NCAW both chemically and physically. The tests simulated those conditions ...
Plans for the disposal of radioactive liquid and solid wastes presently stored in double-shell tanks at the Hanford Site call for retrieval and processing of the waste to create forms suitable for permanent disposal. Waste will be retrieved from a tank using a submerged slurry pump in conjunction with one or more rotating slurry jet mixer pumps. Pacific Northwest Laboratory (PNL) has conducted tests using simulated waste slurries to assess the effects of a impinging slurry jet on the corrosion rate of the tank wall and floor, an action that could potentially compromise the tank`s structural integrity. Corrosion processes were investigated on a laboratory scale with a simulated neutralized cladding removal waste (NCRW) slurry and in a subsequent test with simulated neutralized current acid waste (NCAW) slurry. The test slurries simulated the actual NCRW and NCAW both chemically and physically. The tests simulated those conditions expected to ...
We study the signals for composite vector leptoquarks in e"+e- colliders (CERN e"+e- collider LEP II, Next Linear Collider, and CERN Linear Collider) through their effects on the production of jet pairs, as well as their single and pair productions. We also analyze their production in #gamma#e and #gamma##gamma# collisions.
This standard addresses the design bases for light water reactor, nuclear power plant structures and components essential for the protection of public health and safety from the potential adverse effects of pipe whip, jet impingement, pressurization of compartments outside containment, environmental conditions and flooding associated with a postulated pipe rupture. The design bases for missile protection and the design bases for containment pressurization are not within this standard.
A general relativistic model for the formation and acceleration of lowmass-loaded jets from systems containing accreting black holes is presented. The model is based on previous numerical results and theoretical studies in the Newtonian regime, but modified to include the effects of space-time curvature in the vicinity of the event horizon of a spinning black hole. It is argued that the boundary layer between the Keplerian accretion disk and the event horizon is best suited for the formation and acceleration of the accretion-powered jets in active galactic nuclei and micro-quasars. The model presented here is based on matching the solutions of three different regions: i- a weakly magnetized Keplerian accretion disk in the outer part, where the transport of angular momentum is mediated through the magentorotational instability, ii- a strongly magnetized, advection-dominated and turbulent-free boundary layer (BL) between the outer cold accretion ...
Details are given of the Sasol operation in South Africa. Flow sheets are provided for Sasol 1 and Sasol 2 and 3. The Sasol 1 plant produces waxes, liquid fuels, pipeline gas and chemicals; the Sasol 2 and 3 plants primarily produce ethylene, gasoline and diesel fuel. The versatility of the process is emphasized. The product selectivities of the fixed bed and Synthol reactors are shown and the properties of the products are compared. The influence of the catalyst on selectivity is examined.
The catalytic dehydration of methanol to dimethyl ether was investigated for application on-board a methanol fuelled vehicle. Several catalysts have been tested in a fixed bed reactor. Our approach is to develop a small and efficient reactor converting liquid MeOH under pressure and at low reaction temperatures. (author) 2 figs., 5 refs.
... Piled foundations were adopted and precast concrete piles 6 - 8 m long were driven through the alluvial soils onto a solid bed rock. Special precautions were taken to ensure vibrations did not affect an adjacent apartment block. 88 piles were driven in 2 working days. Navigation - Home - Services - Previous projects - Contact Us - Philosophy - About us - Water Slides - Links ...
The invention deals with an offshore drilling or production platform in particular designed for quake-active areas. The platform rests on the sea bed with a low-gravitational weight and anchored to stabilized pile foundations absorbing the horizontal and vertical acting forces from earthquakes. The platform including pillars can be made of different materials, prestressed concrete in particular. 3 figs.
General conclusions, principles and order of substantiating the extractable reserves and coefficients of oil extraction from oil and oil and gas fields are presented. Recommendations are made for solving questions of constructing calculation models for heterogeneous beds, schematization of the working conditions, selection of mathematical models for oil extraction for different geological-field conditions and different stages of ''life'' of the field.
In the case of a release of residual power and fragmenting following a hypothetical accident the applied powers are small. The boiling in the fluid in the bed promotes leveling and the angles of repose obtained are very small. For a specific power in water of 3.1 W/cm_3 a limiting angle of repose of less than 2 degrees is obtained after a time interval of between 1 and 3 hours. EDULCOREE-and ETABUL-research programs are carried out. (DG).
Using an experimental pilot plant, designed and built for the tests, the influence of the following parameters was determined: desulphurization of the test gas, temperature, residence time in the reactor tube, concentration of the hydrogen sulphide and desulphurization agent, size of the particles which comprise the agent and composition of the gas. Allowance was made for the effect of calcination and carbonisation. Desulphurization was carried out with limestone on a gaseous mixture of CO and H/sub 2/. A mathematical description of the test findings and yield is presented. 8 refs.
New Brunswick has appreciable fossil-fuel reserve potential, particularly in oil shales and to a lesser extent in high-sulfur coal. Each of these resources on their own, however, has problems which could restrict their development. To offset these problems it is proposed that coal and oil shale resources can be used together to overcome these difficulties and effect an attractive, economically viable, energy recovery system. One way is o use coal/oil shale blends, rather than the more conventional coal/limestone mixtures, as feed to fluid-bed combustors for steam generation. The sulfur from the coal is fixed on the spent shale, with the shale combustibles contributing to thermal output. Similarly, oil shale can be used in place of limestone as a combustion scrubber medium to clean emissions from existing conventional coal-fired plants. Several scenarios for the co-use of high-sulfur coal and oil shale are proposed in this report. All involve recovery of energy from ...
Restructuring was carried out on a sedimentary basin structure model of the Osaka plain including Osaka Bay by using newly obtained underground structural data. After the Hygoken-nanbu Earthquake of 1995, a large number of underground structure investigations have been performed in Osaka Bay and urban areas of Kobe and Osaka. However, very few surveys have been done in areas peripheral to Osaka Prefecture, such as the Ikoma area. Therefore, an attempt has been made to increase the number of measuring points to acquire underground structural data of these areas. Estimation of basic rock depths has utilized the dominant cycles in H/V spectra obtained from micro vibration survey, and good correlation of the base rock depths derived by a refraction exploration and a deep-bed boring investigation. With regard to bed division and P- and S- wave velocities in sedimentary beds in the Osaka sedimentary basin, an underground ...
Discussions were given on the characteristics of a diesel engine to emit unburned hydrocarbon (HC) created in a long idling operation. The engine tested in the experiment is a direct injection diesel engine with six water-cooled were investigated varying the jet hole diameter and length of the jet nozzle. In the initial operation period, the HC showed high values. This is thought because part of the injected fuel has deposited on the wall because of low combustion chamber wall temperature, and the fuel deposit that did not evaporate during combustion evaporated during expansion process and emitted unburned. The head was dismantled to investigate the carbon flowers deposited on the nozzle and the relationship between the carbon and the HC deposited on the head face and the combustion chamber wall. It was clarified that the HC increase was phenomenal compared with that of the carbon. This is because the injected fuel was adsorbed into the carbon, ...
A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial extent of each flow regime decreases with increasing gas velocity through the ...
A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial extent of each flow regime decreases with increasing gas velocity through the ...
The analytical results of blowdown characteristics and thrust forces were compared with the experiments, which were performed as pipe whip and jet discharge tests under the PWR LOCA conditions. The blowdown thrust forces were obtained by Navier-Stokes momentum equation for a single-phase, homogeneous and separated two-phase flow, assuming critical pressure at the exit if a critical flow condition was satisfied. The following results are obtained: (1) The node-junction method is useful for both the analyses of the blowdown thrust force and of the water hammer phenomena. (2) The Henry-Fauske model for subcooled critical flow is effective for the analysis of the maximum thrust force under the PWR LOCA conditions. The jet thrust parameter of the analysis and experiment is equal to 1.08. (3) The thrust parameter of saturated blowdown has the same one with the value under pressurized condition when the stagnant pressure is chosen as the saturated ...
A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magnetic perturbation field on the JET tokamak. Calculation results from the momentum transport analysis show that the torque induced by the n = 1 perturbation field has a global profile. The maximal value of this torque is at the plasma core region (#rho# < 0.4) and it is about half of the neutral beam injection torque. The calculation shows that the plasma is mainly in the #nu#_-#sq root##nu# regime in the plasma core, but it is close to the transition between the 1/#nu# and #nu#_-#sq root##nu# regimes. The neoclassical toroidal viscosity (NTV) torque in the 1/#nu# and #nu#_-#sq root##nu# regimes is calculated. The observed torque is of a magnitude in between that of the NTV torque in the 1/#nu# and #nu#_-#sq root##nu# regimes. The NTV torque in the #nu#_-#sq root##nu# regimes is enhanced using the Lagrangian variation of the magnetic field strength. However, it is ...
We present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 {+-} 1.8 events are expected from background contributions. We measure a t{bar t} production cross section of 5.6{sub -1.1}{sup _1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb.
A series of tests has been carried out to determine the operating conditions required to remove the corrosion deposit from samples cut from Winfrith Steam Generating Heavy Water Reactor (WSGHWR) primary circuit pipework by submerged water jetting. Two types of samples were used - one set subjected to the normal annual reactor decontamination using TURCO reagents, the other set having been given a LOMI treatment in addition. Tests showed that useful decontamination factors could be achieved on both types of sample, but significantly less severe operating conditions were required to decontaminate the LOMI treated samples. A decontamination factor of 10 was achieved on TURCO treated samples at 360 Bar; only 200 Bar was required to achieve the same decontamination factor on LOMI treated samples. No metal erosion of the stainless steel substrate was found to occur at these pressures. (author).
Within the framework of the EU power plant conceptual study (PPCS), helium-cooled modular divertor concepts have been investigated in detail at the Forschungszentrum Karlsruhe during the past few years. The first conceptual design proposed was based on convective cooling with the use of flow promoters in the form of pin and/or slot arrays (HEMP/HEMS) to increase the cooling surface and, hence, enhance the heat transfer capacity. While continuing the design optimisation, an advanced multiple-jet design (HEMJ) was introduced, which is based on direct jet-to-wall impinging cooling and offers advantages in terms of simple construction and manufacturing. Main emphasis of the 2004 work program (TW4-TRP-001) lay on experiments for the concepts HEMJ and HEMS, which were mainly performed at the Efremov Institute in St. Petersburg, Russia. For experiment preparation, detailed test programs were worked out and accompanying CFD analyses were accomplished. ...
Magnetically driven non-stationary acceleration of jets in active galactic nuclei results in the leading parts of the flow being accelerated to much higher Lorentz factors than in the case of steady-state acceleration with the same parameters. The higher Doppler-boosted parts of the flow may dominate the high-energy emission of blazar jets. We suggest that highly variable GeV and TeV emission in blazars is produced by the faster moving leading edges of highly magnetized non-stationary ejection blobs, while the radio data trace the slower-moving bulk flow. Thus, the radio and gamma-ray emission regions have different, but correlated, Doppler factors. High-energy emission is generated, typically within the optically thick core, in the outer parts of the broad-line emission region, avoiding the radiative drag on the faster parts of the flow. The radio emission should correlate with the gamma-ray emission, delayed with frequency-dependent time lag ...
An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to help plasma formation. A second improvement consists of a cavity ...
The performance of the new combustor was tested. Experiments showed that this combustor has superior insulating quality than the previous one. Measured radial concentrations indicated uniform distribution of the primary fuel (coal) inside the fire tube resulting in reasonably flat concentration profiles. However, measured radial concentrations after the addition of the reburn fuel showed uneven distribution of the fuel resulting in parabolic concentration profiles, an indication of insufficient mixing in the reburn zone. In order to study mechanisms of nitrogenous species destruction in the reburn zone, it is necessary to achieve adequate mixing if the assumption of one dimensional plug flow behavior is to be valid. Thus, it became necessary to modify the injector design and the injection mode of the reburn fuel to achieve an adequate level of mixing which is the focus of this report. The results show that a minimum reburn fuel jet velocity of 15 m/s (standard ...
Precise measurements of the single spin asymmetry AN, and the double spin asymmetry ANN, in proton-proton (pp) elastic scattering in the region of four-momentum transfer squared 0.0012 have been performed using a polarized atomic hydrogen gas jet target and the Relativistic Heavy Ion Collider (RHIC) polarized proton beam. We present measurements of AN and ANN at center-of-mass energies ?(s)=6.8 and 13.7 GeV. These spin-dependent observables are sensitive to the poorly known hadronic spin-dependent amplitudes. Comparing AN at different energies, a ?(s) dependence of the hadronic single spin-flip amplitude is suggested. A hadronic double spin-flip amplitude from the ANN data is consistent with zero within a 2-? level. We also present ??T, estimated from the measured ANN data. The results for ??T are consistent with zero. Our results provide significant constraints toward a comprehensive understanding of the reaction mechanism for pp elastic scattering.
This paper reports thermal comfort and indoor air quality (IAQ) studies of an under-floor air-conditioning (UFAC) system in a hot and humid climate. Thermal comfort parameters were measured at pre-determined grid points within an imaginary plane to predict the air flow pattern of the supply air jet as well as to determine the occurrence of thermal stratification in the office space. Fanger's thermal comfort index was also computed to detect the occupants' thermal sensation. Besides, the concentration levels of dust and carbon dioxide were recorded with the intention to examine the quality of the indoor air. Statistical methods were applied to derive the relationship between air velocity and the other parameters as mentioned earlier. The main findings from the study revealed reasonable level of acceptability of IAQ associated with the UFAC system. However, occupants are likely to experience localised thermal discomfort near the supply diffusers due ...
The purpose of this project is to demonstrate targeted infill and extension drilling opportunities, better determinations of oil-in-place, methods for improved completion efficiency and the suitability of waterflooding in certain shallow-shelf carbonate reservoirs in the Williston Basin, Montana, North Dakota and South Dakota. Cores from five Red River wells in the Bowman-Harding study area have been examined and described in detail; contracts have been awarded for a 3-D survey in Bowman Co., ND and a 2D, multi-component survey in Richland Co.; extended-time pressure buildup data have been analyzed from two wells which are candidates for jetting-lance completion workovers; a 20-day injectivity test has been completed in the Red River (upper member); a jetting-lance completion program has commenced with one job completed and three more scheduled during April; and reservoir data from three key Red River fields in the Bowman-Harding study area has ...
We discuss the impact for light neutralinos in an effective Minimal Supersymmetric extension of the Standard Model of the recent results presented by the CMS and ATLAS Collaborations at the CERN Large Hadron Collider for a search of supersymmetry in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 35 inverse pb. We find that, in the specific case of light neutralinos, efficiencies for the specific signature searched by ATLAS (jets+missing transverse energy and an isolated lepton) imply a lower sensitivity compared to CMS (which searches for jets +missing transverse energy). Focusing on the CMS bound, if squark soft masses of the three families are assumed to be degenerate, the combination of the ensuing constraint on squark and gluino masses with the experimental limit on the b to s + gamma decay imply a lower bound on the neutralino mass that can reach the value of 11.9 GeV, depending on the gluino ...
We report coupling and guiding of pulses of peak power up to 0.3 TW in 1.5 cm long preformed plasma waveguides generated in a high repetition rate argon gas jet. Coupling of up to 52% was measured for 50 mJ, -110 fs pulses injected at times longer than 20 ns, giving guided intensities up to -5x1016 W/cm2. It was found that for short delays between waveguide generation and pulse injection, pulse shortening occurred, with this effect reduced as delay was increased. Injection into the waveguide of two consecutive pulses separated by a few nanoseconds resulted in the reduction of shortening of the second pulse at all delays. Femtosecond time-resolved shadowgrams of the coupling of injected pulses into the waveguide show that there is ?0.5 mm of neutral gas remaining at the waveguide entrance after waveguide generation.
The application of foam in dealing with underground fire is well known due to its smothering action by cutting off air feed to burning fuel as well as acting as coolant. Besides plugging air feed to fire, water could be virtually reached to the fire affected areas much beyond the jet range as underground galleries with low roof restrict jet range of water. This method also enables a closer approach of a fire fighting team by isolating the toxic gases and smoke with a foam plug. The paper describes the development of high expansion foam composition and its application technology in order that foam plug method can be suitably utilized for combating mine fires in India. Three compositions were recommended for generation of high expansion foam: (a) 0.5% sodium/ammonium lauryl sulphate, 0.15 to 0.2% sodium carboxy methyl cellulose, 0.1% booster; (b) 0.5% sodium/ammonium lauryl sulfate, 0.12 to 0.15% alkaline solution of gum arabic, 0.1 to 0.2% ...
This research has been proceeded over the potential core region (H/B=2) of two-dimensional impinging air jet system, in which square rods(width of 6 mm) has been set up in front of heating surface in order to increase heat transfer. The objective of this research was to investigate the characteristics of heat transfer and air flow, in cases of the clearance from rods to heating surface (C = 1, 2, 4, 6 mm) and the pitch between each rods(P = 30, 40, 50 mm) changed. And this research compared the above with the experimentation without rods. As result, heat transfer performance was best under the condition of C = 1 mm, in case clearance changed, and there was no serious difference in the effect of heat transfer augmentation in the case of pitch of rods changed. (author) 11 refs. 12 figs.
Si nanocrystal floating gate MOS capacitors were formed on p-Si (100) wafers by thermal plasma jet (TPJ) annealing of SiO2/SiOx /SiO2/Si(100) stacked structure. The chemical composition of SiOx layer was controlled by changing the SiH4, He, and O2 gas flow ratio during plasma enhanced chemical vapour deposition. The MOS capacitors showed clear hysteresis in capacitance-voltage (CV) characteristics after TPJ annealing. The hysteresis width shows maximum value when initial composition x =1.7, which shows the maximum photoluminescence (PL) intensity. The maximum hysteresis width of 6.8 V was observed with gate voltage swept between 20 and -20 V in x = 1.7 sample. The result means 7.4 x 1012 cm-2 carriers are injected to or emitted from Si nanocrystals. The duration of 1 V shift in flatband vo...
Apparatus for minimizing thermal loss in a windowless, open cavity solar receiver due to airflow at the receiver aperture includes means for deflecting wind away from the cavity opening such that flow stream reattachment occurs away from the receiver aperture to provide a dead air zone at the cavity opening. This prevents turbulent-mixing airflow exchange between ambient air and heated air within the solar receiver. The wind deflector apparatus includes either a passive annular deflection foil at the receiver aperture, or an active device for producing an outwardly projected air jet at the receiver aperture.
Design methods and parameters are described which are addressed when considering consequences of a postulated pipe rupture event in a nuclear plant design. Parameters discussed are break opening time and size, resultant blowdown characteristics of the effluent from the broken pipe, jet reaction and impingement loading, pipe motion, and pipe impact loading on steel and concrete structures. The impact the various parameters have on overall plant designs and conservatisms inherent in each consideration are evaluated in a qualitative nature. Finally, recommendations are provided for each parameter discussed for further evaluation and study.
>The causes and implications of the impeading shortages of gasoline, heating oil, diesel fuel, jet fuel, and electricity were investigated at the May 3, 1973 hearings. Discussions and related data were presented on short-term fuel shortages and their effects on the electric utilfties and the present situation in the regulated energy industries and its effects on energy R&D. The statement of the national oil lobbers council is presented in an appendix. (MCW)
This safety design guide for pipe rupture protection identifies high-energy systems in which pipe ruptures must be postulated to occur, as well as systems that must be protected from the dynamic effects of such ruptures. Dynamic effects considered in this SDG consist of pipe whip (including missiles generated by pipe ruptures, if any) and jet impingement, Requirements for protection against the dynamic effects of a postulated pipe rupture and method of protection of essential structures, systems and components are specified for these effects. The change status for the regulatory requirements, code and standards should be traced and this safety design guide shall be updated accordingly. 2 tabs., 5 refs. (Author) .new.
We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a brightness temperature limit of about 10.000 K, and an expected dynamic range in future VLBI maps of better than 1.000.000, the impact of SKA on the research of compact extragalactic radio sources and their energetic jets will be very strong. We discuss some consequences, including a possible combination of SKA with future space VLBI missions.
This student manual, part of a small-engine repair series on servicing fuel systems, is designed for use by special needs students in Texas. The manual explains in pictures and short sentences, written on a low reading level, the job of replacing carburetor diaphragms. Along with the steps of this repair job, specific safety and caution information is frequently noted. To reinforce consistency in material presented to the slow learners, the pictures and written words correspond exactly with the pictures and wording on a corresponding audiovisual presentation. A progress chart for rating the students is included in the manual. (KC)
The signature of the negative snakes from the soft X-ray cameras is very similar to the more usual snakes except that the localised region of the snake has, compared with its surroundings, decreased rather than increased emission. Circumstances where negative snakes have been seen are reviewed. The negative snake appears as a region of increased resistance and of increased impurity density. The relationship between the shear and the current perturbation is shown, and it seem probable that the magnetic shear is reversed at the point of the negative snake, i.e. that q is decreasing with radius. 6 refs., 6 figs.
The first measurement of the pn{yields}d{omega} total cross-section has been achieved at mean excess energies Q{approx}28 and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Juelich and that of the slow ''spectator'' proton (p{sub sp}) from the pd{yields}p{sub sp}d{omega} reaction in a silicon telescope placed close to the target. The cross-sections lie above those measured for pp{yields}pp{omega} but seem to be below theoretical predictions. (orig.)
multi-parton interactions and underlying event structure, $\\gamma$-mediated processes and luminosity determination, Monte Carlo tuning and even MSSM Higgs discovery in central exclusive production. In this article, the forward detector instrumentation around the CMS interaction point is described and the prospects for diffractive and forward physics using the CMS forward detectors are summarized. In addition, first observation of forward jets as well as early measurements of the forward energy flow in the pseudorapidity range $3.15
Neutral atom beams with energies above 200 keV may be required for various purposes in magnetic fusion devices following TFTR, JET and MFTF-B. These beams can be produced much more efficiently by electron detachment from negative ion beams than by electron capture by positive ions. We have investigated the efficiency with which such neutral atoms can be produced by electron detachment in partially ionized hydrogen plasma neutralizers.
Alpha particle confinement is necessary for ignition of a D-T tokamak fusion plasma and for first wall protection. Due to high radiation backgrounds and temperatures, scintillators and semiconductor detectors may not be used to study alpha particles which are lost to the first wall during the D-T programs on JET and ITER. An alternative method of charged particle spectrometry capable of operation in these harsh environments, is proposed: it consists of thin foils of electrically isolated conductors with the flux of alpha particles determined by the positive current flowing from the foils. 2 refs., 3 figs.
The existence of light hidden sectors is an exciting possibility that may be tested in the near future. If DM is allowed to decay into such a hidden sector through GUT suppressed operators, it can accommodate the recent cosmic ray observations without over-producing antiprotons or interfering with the attractive features of the thermal WIMP. Models of this kind are simple to construct, generic and evade all astrophysical bounds. We provide tools for constructing such models and present several distinct examples. The light hidden spectrum and DM couplings can be probed in the near future, by measuring astrophysical photon and neutrino fluxes. These indirect signatures are complimentary to the direct production signals, such as lepton jets, predicted by these models.
The present analysis shows that the observed efficiency of current drive with synergy between LHCD and ICRH is in good agreement with the relativistic theory of Karney and Fisch for Landau damped waves. The predicted power absorption from the fast wave by the electron tail is within 30% of the measured value. In the presence of significant fast electron diffusion within a slowing down time it would be possible to produce central current drive using multiple ICRF resonances even when the LHCD deposition is at half radius, as in an ITER type device. (authors). 4 refs., 6 figs.
Essential to today's modern refineries and the gasoline production process are fluidized catalytic cracking units. By using a computational fluid dynamics (CFD) code developed at Argonne National Laboratory to simulate the riser, parametric and sensitivity studies were performed to determine the effect of catalyst inlet conditions on the riser hydrodynamics and on the product yields. Simulations were created on the basis of a general riser configuration and operating conditions. The results of this work are indications of riser operating conditions that will maximize specific product yields. The CFD code is a three-dimensional, multiphase, turbulent, reacting flow code with phenomenological models for particle-solid interactions, droplet evaporation, and chemical kinetics. The code has been validated against pressure, particle loading, and product yield measurements. After validation of the code, parametric studies were performed on various parameters such ...
The progression of hypothetical core disruptive accidents in metallic fuel fast breeder reactors is strongly affected by the fragmentation of molten metallic fuels due to the molten fuel-coolant interaction (FCI). As a basic study of FCI, the present paper focuses on the fragmentation of a single molten copper droplet with mass from 1 to 5 g, which penetrated a sodium pool at instantaneous constant interface temperatures (Ti) from 995 to 1,342degC. Intensive fragmentation of a single molten copper droplet was clearly observed even if Ti values are below the melting point (1,083degC) of copper besides the higher Ti range. The intensive fragmentation shows that the mass median diameters (Dm) of copper droplets with a fivefold difference in mass or the same mass have little difference, i.e., they are nearly the same. Under the lower Ti condition, the Dm data of droplet fragments of both the same and different masses scatter widely. It is found that the present Dm/D0 data of mass median ...
Using infra-red (IR) thermography, power loads onto the MKII Gas-Box divertor targets have been investigated in Type-I ELMy H-Mode plasmas at JET in medium current discharges (Ip = 2.6 MA and BT = 2.7 T). Heat fluxes are calculated from the measured divertor target tile surface temperatures taking into account the influence of co-deposited surface layers on tile surfaces. This is particularly important when estimating the energy deposition during transient events such as ELMs. Detailed energy balance analysis is used, both from IR and tile embedded thermocouples, to demonstrate an approximately constant ELM-averaged in/out divertor target asymmetry of ?0.55 and to show that the ELM in/out energy deposition ratio ranges from 1 : 1 to 2 : 1. The inter-ELM in/out ratio is close to the ELM-averaged value at low pedestal collisionalities and decreases down to values close to zero when the inner target plasma detaches at the highest pedestal collisionalities. The ...