WorldWideScience

Sample records for air preheaters

  1. Improved design and operation of crude furnace air preheater for cold climates

    Energy Technology Data Exchange (ETDEWEB)

    Gollpudi, B. [Bantrel Co. (Canada); Nichols, D. [Husky Energy (Canada)

    2011-07-01

    In the heavy oil industry, air preheaters are used to heat combustion air with hot flue gas. Flue gas contains significant amounts of sulphur oxides which can result in acid dew point corrosion on the flue gas side. The air preheater metal has therefore to be kept at a temperature higher than this dew point to provide trouble free operation. This paper relates a case of dew point corrosion damage in an air preheater and the design modifications made to solve the problem. The case studied took place at the crude furnace at Husky Energy's Lloydminster Upgrader where a plate exchanger air preheater was installed in 2007 and corrosion was noticed in 2009. It was found that hot air recirculation helps in maintaining a sufficiently high temperature and that the ducting design avoids dead zones. This paper showed that improved design can help to prevent damage occurring in the air preheater.

  2. Prediction and mitigation of air preheater fouling due to ammonium bisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, R.; Tavoulareas, S.; Stallings, J. [Energy and Environmental Strategies, MA (United States)

    2001-07-01

    This paper provides a brief review of the fundamentals of ammonium bisulfate (ABS) formation, deposition and fouling in the air preheater. It presents a software-based predictive model for assessing the potential for air preheater fouling as a result of proposed SNCR or SCR retrofits and considering site-specific conditions and introduces a software-based cost-benefit model for assessing the economic trade-offs of various ABS fouling mitigation options. 7 refs., 13 figs.

  3. Corrosion on air preheaters and economisers; Korrosion hos luftfoervaermare och ekonomisrar

    Energy Technology Data Exchange (ETDEWEB)

    Nordling, Magnus

    2012-05-15

    Combustion plants in Sweden are exposed to considerable stress regarding low temperature corrosion, and failures due to low temperature corrosion occur regularly. Particularly common is corrosion problems connected to air preheaters and economisers. The number of combustion plants having air preheaters and economisers is however large, and the result of a collection of experiences regarding corrosion on air preheaters and economisers therefore has the potential to give a broad knowledge base. The summary of collection of experiences that has been done here, complemented with a literature survey, is expected to give plant owners and plant constructors a valuable tool to prevent corrosion on the flue gas side of air preheaters and economisers. The choice of plants for the inquiry was made using a list from the Swedish Naturvaardsverket (Environmental Protection Agency) indicating the emissions of NO{sub x}gases from Swedish combustion plants. From that list mainly the plants with the largest emissions were chosen, resulting in a number of 30 plants. Depending on that most of the plants have several boilers, and that the connected tubes often have several economisers and air preheaters, the number of economisers and air preheaters in this experience collection is at least 85. The study was however not limited to economisers and air preheaters, but also experiences connected to corrosion of other units were collected when mentioned, and the most interesting information here is also included in the report. Also a number of the plants were visited to improve the basis of the report, e.g. by photographing the most interesting parts. As the insight of the extension of the problem increased, renewed interview rounds were made, and the last one was made in August 2011.

  4. Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2015-01-01

    Full Text Available This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h and catalytic oxidation bed average temperature (20°C to 560°C within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry.

  5. The benefit of solid oxide fuel cells with integrated air pre-heater

    Energy Technology Data Exchange (ETDEWEB)

    Costamagna, P. [Univ. degli Studi di Genova, Fac. di Ingegneria, ISTIC, Inst. di Ingegneria Chimica e di Processo `G.B. Bonino`, Genova (Italy)

    1997-11-01

    A new design has recently been proposed in the field of solid oxide fuel cells, consisting of a traditional electrochemical cell integrated with a pre-heater. In this paper a simulation model for the rectangular planar solid oxide fuel cell with integrated air pre-heater is presented. A two-dimensional stack simulation is presented as well, one axis coincides with the fuel flow direction, the other with the stack height. Local quantities such as current density, gas and solid temperatures are reported and cell characteristics predicted. In a parameter study, effects of oxygen utilisation and heat-transfer conditions in the pre-heater on the local temperature distribution of the solid structure are considered. As a result, the benefit of the new cell design becomes evident when low air flow rates are applied. A further advantage associated with the reduced flow rate is the low air temperature at the inlet. (orig.)

  6. Electronically Controlling the System of Preheating Intake Air by Flame for Diesel Engine Cold-Start

    Institute of Scientific and Technical Information of China (English)

    杜巍; 赵福堂

    2003-01-01

    In order to improve the cold-start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self-ignite at the end of compression process at different temperatures of coolant and intake-air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro-controller unit (MCS-8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.

  7. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater

    Energy Technology Data Exchange (ETDEWEB)

    J. Menasha; D. Dunn-Rankin; L. Muzio; J. Stallings [University of California Irvine, Irvine, CA (United States). Department of Mechanical and Aerospace Engineering

    2011-07-15

    Ammonium bisulfate (ABS) forms in coal-fired power plant exhaust systems when ammonia slip from the NOx control system reacts with the sulfur oxides and water in the flue gas. The critical temperature range for ABS formation occurs in the air preheater, where ABS is known to cause corrosion and pluggage that can require unplanned outages and expensive cleaning. To develop mitigation strategies for the deleterious effects of ABS in air preheaters, it is important to know its formation temperature and deposition process. This paper describes a bench-scale experimental simulation of a single-channel air preheater, with the appropriate temperature gradient, used in conjunction with simulated coal combustion flue gas, including sulfur oxides, ammonia, and water vapor, to investigate the formation of ABS. Formation was observed optically, and the formation temperature, as well as deposition characteristics for a realistic range of reactant concentrations are presented and compared with previous studies on ABS formation. This study presents data at realistic concentrations not earlier tested, and the reported data has smaller experimental uncertainty than previously obtained. We found that the measured ABS formation temperatures under air preheater channel conditions lies between the temperatures reported by others, and is in the range of 500-520 K for typical flue gas concentrations of ammonia and sulfur oxide species. The results also show that, at least for this experimental configuration, ABS forms predominantly as an aerosol in the gas phase rather than as a condensate on the channel walls. 13 refs., 13 figs., 2 tabs.

  8. Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fired Heat Treatment Furnace

    Directory of Open Access Journals (Sweden)

    E B Muhammed Shafi,

    2015-09-01

    Full Text Available This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating. The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC is obtained. The test was caaried out at Peekay Steels Casting (P ltd, Nallalam, Calicut.

  9. 空气预热器的改造%Revamping of air preheater

    Institute of Scientific and Technical Information of China (English)

    廖艳玲

    2011-01-01

    The revamping of air preheater in the waste heat recovery system of a 4.1 MM TPY diesel hy-drotreating unit in SINOPEC Qingdao Refining & Chemical Co. , Ltd. Was introduced. An analysis was performed on how to revamp the air preheater to reduce flue gas emission temperature of waste heat recovery system so as to improve the thermal efficiency of fired heaters. After revamping, the flue gas emission temperature is about 30 ℃ lower than that before the revamping, the thermal energy obtained by the air is much higher than that before replacement of pre-heater tubes and energy saving is significant.%介绍了中国石化青岛炼油化工有限责任公司余热回收系统的空气预热器的改造情况,分析了如何通过对空气预热器的改造来降低余热回收系统排烟温度,从而提高加热炉的热效率.改造后,烟气排烟温度比改造前降低30℃左右,空气所获得的能量比更换热管前有较大提高,节能效果显著.

  10. Combustion Air Pre-heating from Ash Sensible Heat in Municipal Waste Incineration Systems

    Directory of Open Access Journals (Sweden)

    Zakariya Kaneesamkandi

    2014-01-01

    Full Text Available Heat recovery from bottom ash is more important in municipal waste combustion systems than in any other solid fuel combustion since almost 50% of it comprises of non-combustibles. In this study, an ash cooling system using air as the cooling medium has been modeled for pre-heating the combustion air. Air cooling has several advantages over water cooling methods. The study involves modeling using Gambit tool and is solved with the fluent solver. Municipal solid waste incineration systems have the advantage of being located near the waste collection area apart from the high volume reduction ratio. Improvements in the emission control systems and combustion technology can make incineration a highly feasible disposal method. Low furnace temperature due to heat losses through fuel moisture loss and ash sensible heat loss has been a disadvantage with these systems. In this study, a small percentage of the combustion air is pre-heated in a non-contact type heat exchanger and its effect on the available energy of combustion gases at the evaporator outlet is studied. The study is performed for two different waste samples. Results indicate significant increase in available energy at the evaporator outlet and better relative performance for the lower grade fuel. A comparison is made with similar methods reported in the literature along with a brief discussion on the methodologies adopted. The results confirm the importance of installing ash sensible heat recovery mechanism for waste incineration systems as well as the feasibility of the air based method.

  11. Gasifier selection, design and gasification of oil palm fronds with preheated and unheated gasifying air.

    Science.gov (United States)

    Guangul, Fiseha M; Sulaiman, Shaharin A; Ramli, Anita

    2012-12-01

    Oil palm frond biomass is abundantly available in Malaysia, but underutilized. In this study, gasifiers were evaluated based on the available literature data and downdraft gasifiers were found to be the best option for the study of oil palm fronds gasification. A downdraft gasifier was constructed with a novel height adjustment mechanism for changing the position of gasifying air and steam inlet. The oil palm fronds gasification results showed that preheating the gasifying air improved the volumetric percentage of H(2) from 8.47% to 10.53%, CO from 22.87% to 24.94%, CH(4) from 2.02% to 2.03%, and higher heating value from 4.66 to 5.31 MJ/Nm(3) of the syngas. In general, the results of the current study demonstrated that oil palm fronds can be used as an alternative energy source in the energy diversification plan of Malaysia through gasification, along with, the resulting syngas quality can be improved by preheating the gasifying air.

  12. Waste Heat Recovery by Heat Pipe Air-Preheater to Energy Thrift from the Furnace in a Hot Forging Process

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

    Full Text Available Problem statement: Currently, the heat pipe air-preheater has become importance equipment for energy recovery from industrial waste heat because of its low investment cost and high thermal conductivity. Approach: This purpose of the study was to design, construct and test the waste heat recovery by heat pipe air-preheater from the furnace in a hot brass forging process. The mathematical model was developed to predict heat transfer rate and applied to compute the heat pipe air-preheater in a hot brass forging process. The heat pipe air-preheater was designed, constructed and tested under medium temperature operating conditions with inlet hot gas ranging between 370-420°C using water as the working fluid with 50% filling by volume of evaporator length. Results: The experiment findings indicated that when the hot gas temperature increased, the heat transfer rate also increased. If the internal diameter increased, the heat transfer rate increased and when the tube arrangement changed from inline to staggered arrangement, the heat transfer rate increased. Conclusion/Recommendations: The heat pipe air-preheater can reduced the quantity of using gas in the furnace and achieve energy thrift effectively.

  13. FAILURE ANALYSIS IN TUBING OF AIR PREHEATER OF BOILER FROM A SUGARCANE MILL

    Directory of Open Access Journals (Sweden)

    Joner Oliveira Alves

    2014-10-01

    Full Text Available The increased demand for energy from sugarcane bagasse has made the sugar and alcohol mills search alternatives to reduce maintenance of the boilers, releasing more time to the production. The stainless steel use has become one of the main tools for such reduction. However, specification errors can lead to premature failures. This work reports the factors that led tubes of AISI 409 stainless steel fail after half season when applied in a air preheater of boiler from a sugarcane mill. In such application, the AISI 304 lasts about 15 seasons and the carbon steel about 3. A tube sent by the sugar mill was characterized by wet chemical analysis, optical microscopy and EDS. Results indicated chloride formation on the internal walls of the tube, which combined with the environment, accelerated the corrosion process. The carbon steel showed high lifetime due to a 70% higher thickness. Due to the work condictions is recommended the use of stainless steels with higher corrosion resistance, such as the traditional AISI 304 or the ferritic AISI 444, the last presents better thermal exchange.

  14. Cast iron air preheater and commercial application%铸铁式空气预热器及工业应用

    Institute of Scientific and Technical Information of China (English)

    王德瑞

    2012-01-01

    As cast iron has a high corrosion resistance performance, the air preheater fabricated from cast iron material is resistant to corrosion and extended in service life. It is especially applicable for the low-temperature section of waste heat recovery system for industry furnace flue gas. The past and present applications of cast iron air preheaters in boiler, iron & steel production and petrochemical industries are described in detail , and the new development of large cast iron plate air preheater developed by SINOPEC in recent years is presented. Up to now, the large cast iron plate air preheaters have been selected in the design of a large number of fired heaters and its design, fabrication and installation technologies are becoming commercially proven. In April, 2010, China' s first new type cast iron plate air preheater came on stream in No. 2 atmospheric-vacuum distillation unit in No. 2 atmospheric-vacuum distillation unit in SINOPEC Wuhan Petrochemical Company. In 19 months' operation, the heat efficiency of the furnace has been maintained at over 92% and the temperature of flue gas emission was lower than 130 t. The preheater has been operating smoothly ever since.%铸铁具有很强的耐硫酸腐蚀能力,因此,采用铸铁材料制作的空气预热器具有耐腐蚀、长寿命的特点,特别适合在工业炉烟气余热回收系统中的低温段采用.介绍了铸铁式空气预热器在国内锅炉、钢铁和石化行业过去和现在的工业应用情况,以及中国石化近年开发的大型铸铁板式空气预热器的最新进展.目前,国产大型铸铁板式空气预热器已在多台火焰加热炉的设计中采用,设计、制造、安装技术日臻成熟.2010年4月,武汉石化2号常减压蒸馏装置投用了国产第一台新型铸铁板式空气预热器,运行19个月,加热炉热效率一直稳定在92%以上,排烟温度一直稳定在130℃以下,运行良好.

  15. Thermal calculation method for quad-sectional regenerative air preheater%四分仓回转式空气预热器热力计算方法

    Institute of Scientific and Technical Information of China (English)

    陈昌贤; 孙奉仲; 李飞; 吴艳艳

    2014-01-01

    A new thermal calculation model for quad-sectional regenerative air preheater was investigated based on the analysis of operating mode and heat transfer characteristics of quad-sectional air preheaters.The model included two cal-culating steps:the average outlet flue gas temperature and the weighted average outlet air temperature were obtained through the first step calculation;and based on the first step calculation results, the average outlet air temperatures were obtained in right-secondary airside, primary air side and left-secondary airside respectively by the second step calcula-tion.The results showed that the maximum and minimum relative deviations between calculated values and design val-ues were 2.27% and 0.21% respectively.For a 300 MW circulating fluidized bed boiler unit with quad-sectional air preheater, the maximum and average relative deviations between calculated values and actual operation data were 4%and 1.8%respectively, the accuracy and reliability of this thermal calculation model were verified.%基于四分仓空气预热器的运行方式和传热特点的分析,建立了先合仓再分仓的热力计算模型。模型包含合仓和分仓两步计算,通过合仓计算获得平均出口烟温和有加权的平均出口风温;利用合仓计算结果进行分仓计算,获得右二次风仓、一次风仓和左二次风仓的平均出口风温。结果表明,计算值与设计值的最大相对偏差为2.27%,最小相对偏差为0.21%。以某300 MW循环流化床锅炉机组的四分仓空气预热器为实例,在4个常用工况下,计算值与实际运行数据的最大相对偏差为4%,平均相对偏差为1.8%,验证了此计算方法的准确性和可靠性。

  16. 组合式空气预热器振动原因分析及解决措施%CAUSE ANALYSIS FOR THE VIBRATION OFCOMBINED AIR PREHEATER AND THE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    颜祥富; 侯杰; 龙运国

    2012-01-01

    某组合式空气预热器试运行时产生强烈振动,文章对空气预热器产生震动的原因进行了分析,指出卡门涡流是预热器产生振动的主要原因,因为当气流横向绕流管束时,卡门涡流的交替脱落会引起空气预热器中气柱的振动.当漩涡的脱落频率(fK)与管箱的声学驻波振动频率接近或一致时,会诱发强烈的管箱声学驻波振动,造成空气预热器管箱的共振.为了消除振动,对预热器进行了改造:沿换热管方向安装消振隔板,将预热器从上至下贯通均等分成3个气室(相当于减小气室宽度),以提高气室固有频率及振风量.改造后预热器的卡门涡流频率和气室固有频率不会重合,也就不会产生声学共振.通过改造,该预热器消除了振动,恢复了正常的运行,确保炼化加热炉高效、长周期安全稳定运转.%Certain combined air preheater produced strong vibration during test run. This paper analyzes the causes for the vibration of the air preheater and points out that Karman vortex is the main reason for the vibration of the preheater because the alternating shedding of Karman vortex may cause the column vibration of the air preheater when the air flows through the tube bundle transversely. When the vortex shedding frequency ( /k ) and the frequency of the acoustic standing wave vibration of the tube box is close to each other or consistent, strong acoustic standing wave vibration of the tube box will be induced. And this may cause the resonance of the tube box of the air preheater. In order to eliminate the vibration, the preheater has been transformed. Vibration elimination separators are installed along the heat transfer tube direction and the preheater is divided into three equal chambers from the top to the bottom, which equals to reducing the width of the chamber. This may increase the natural frequency of the chamber and the vibration air volume. After the transformation, the Karman vortex

  17. Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air%使用加热空气的预混天然气催化燃烧的实验研究

    Institute of Scientific and Technical Information of China (English)

    许考; 刘中良; 何洪; 程水源; 马重芳

    2007-01-01

    In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC),NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied.Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃,100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.

  18. Preheating in New Inflation

    CERN Document Server

    Desroche, M; Kratochvil, J; Linde, Andrei D; Desroche, Mariel; Felder, Gary N.; Kratochvil, Jan M.; Linde, Andrei

    2005-01-01

    During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We do a full analysis of preheating in new inflation, using a combination of analytical and numerical methods. We find that the decay of the homogeneous component of the inflaton field and the resulting process of spontaneous symmetry breaking in the simplest models of new inflation usually occurs almost instantly: for the new inflation on the GUT scale it takes only about 5 oscillations of the field distribution. The decay of the homogeneous inflaton field is so efficient because of a combined effect of tachyonic preheating and parametric resonance. At that stage, the homogeneous oscillating inflaton field decays into a collection of waves of the inflaton field, with a typical wavelength of the order of the inverse inflaton mass. This stage usually is followed by a long st...

  19. Application of high strength sonic soot blower in air preheater of 1 000 MW units%高强声波吹灰器在1000 MW机组空预器中的应用

    Institute of Scientific and Technical Information of China (English)

    李彦民; 王俊杰

    2016-01-01

    There are some problems existed in the running of air preheater in CLP vote of Henan Electric Power co. LTD. ,Pingdingshan Power 2 x 1 000 MW ultra supercritical units. The air preheater had a large amount of dust ,so the resistance increased which is one of the important reasons affecting the safe and economic opera-tion. The sonic soot blower is applied in air preheater to prevent the dust and its effect is analyzed. The practi-cal application results show that the efficient acoustic wave sootblower are deposited in the air preheater and has obvious effect, the safety benefit, economic benefit and social benefit are remarkable.%介绍了中电投河南电力有限公司平顶山发电分公司2×1000 MW超超临界机组空预器在运行中出现的大量积灰情况,空预器阻力的大幅增加是影响机组安全、经济运行的重要原因。分析通过空预器加装声波吹灰器后对防止空预器大量积灰的效果,根据实践应用结果表明,高效声波吹灰器对空预器积灰有明显效果,安全效益、经济效益及社会效益显著。

  20. 350 MW超临界直流锅炉空预器堵塞原因分析及处理%Analysis and Treatment of Blockage in Air Preheater of 350 MW Supercritical Once Through Boiler

    Institute of Scientific and Technical Information of China (English)

    崔鹏

    2016-01-01

    The selective catalytic reduction (SCR) by reducing agent of ammonia (NH3) is used to achieve the purpose of removal of NOx in flue gas in boiler denitration system in Hohhot Thermal Power Plant. In the operation of ammonia and NOx cannot all mix, escape is inevitable, when the escape rate of overweight ammonia and sulfur trioxide in flue gas reaction generated hydrogen sulfate ammonia block in air preheater, due to differential pressure increasing of the air preheater. The application of ammonium hydrogen sulfate physical properties will be ammonia decomposition hydrogen sulfate, air preheater body heat will ammonia gasification hydrogen sulfate, eliminating air preheater clogging. Experience can be used as reference in the same type unit.%呼和浩特热电厂2×350 MW机组锅炉脱硝系统采取选择性催化还原法(SCR),使用还原剂氨(NH3)来达到除去烟气中NOx的目的。运行中氨气和NOx不可能全部混合,逃逸无法避免,当逃逸率超标时,氨气与烟气中三氧化硫反应生成硫酸氢铵堵塞空预器,导致空预器前后差压增大。对此根据硫酸氢铵的物理性质,采用空预器降风量升烟温的方法将硫酸氢铵气化,消除空预器堵塞,经验可供同类型机组参考。

  1. 煤气锅炉空气预热器腐蚀原因及对策%Reason and Treatment of Air Preheater Corrosion of Gas-Fired Boiler

    Institute of Scientific and Technical Information of China (English)

    王锐; 刘启学; 孙保顺

    2013-01-01

    结合对75t煤气锅炉低温段空气预热器的改造实例,阐述了煤气锅炉低温段空气预热器因锅炉负荷变化、掺烧焦炉煤气增大等因素而引起的低温段空气预热器低温腐蚀现象,分析了低温段空气预热器腐蚀损坏的原因并提出了相应的预防改进措施。%Combine a instance of the remould to the air preheater of the 75 t gas-fired boiler low temperature segment in Xingtai Iron& Steel Corp .Ltd., describe the actualities of air preheater corrosion of gas-fired boiler be-cause of the boiler load carries change and coke-oven gas flow enlarged etc ..Reasons of air preheater corrosion was an-alyzed, and the solution measures are proposed .

  2. Bringing coal preheating in drum dryers to a commercial level

    Energy Technology Data Exchange (ETDEWEB)

    Babanin, B.I.; Proushin, Yu.E.; Dinel' t, V.M.; Nikolaeva, V.Z.; Shabarshova, Yu.V.; Patrushev, A.N.; Vodop' yanov, A.G.; Vlasov, V.S.; Sementin, V.P.

    1988-10-01

    Discusses operation of a system for coal charge preheating used in Western Siberia since 1965. It is the first coal preheating system constructed in the USSR. The following aspects of system operation are discussed: composition of combustion gases used for coal drying, drying temperature, consumption rate of combustion gases depending on coal moisture content, flue gas recirculation system, transport and storage of dried coal, methods for dust separation (wet and dry), air pollution from coal dryers, and efficiency of air pollution control. Operation of the coal preheating system shows that one-stage coal drying and preheating is economic but associated with increased investment (construction cost) and with increased coal comminution. Large one-stage dryers also cause irregular coal preheating depending on distribution of coal grain size (with overheating of coal fines). Recommendations for design modifications of one-stage dryers are made. 3 refs.

  3. 垃圾焚烧发电厂一次风预热方式的比较分析%Comparison of Preheating Ways of Primary Air in Waste Incineration Power Plants

    Institute of Scientific and Technical Information of China (English)

    李军; 严圣军; 陈竹; 王占磊

    2012-01-01

    A comparison of heating medium in phase II of primary air preheater by ways of superheat steam and drum saturated steam for waste incineration power plants were carried out. The results showed that comparing with drum saturated steam, the weight of steam extraction with superheat steam decreased by 20. 8%, the heat quantity decreased by 8. 7%, the steam flow into the turbine increased, the heat exchanging area in phase II of the preheater can be reduced by about 20%, and the cost can be reduced by about 10%. The superheat steam has advantages of small investment cost, small steam consumption, and higher heat effective utilization. According to waste characteristic, incineration scale and control policy, it could give a reference to select preheat way of primary air, with the new ideas of primary air preheated by boiler feed water and the optimized air preheating way.%对垃圾焚烧发电厂一次风加热器Ⅱ段的加热介质采用锅炉出口过热蒸汽和汽包饱和蒸汽进行比较,结果表明:过热蒸汽抽汽较汽包饱和蒸汽抽汽的抽汽量减少20.8%,热量减少8.7%,并增加了进汽机的蒸汽量,同时预热器Ⅱ段换热面积可减少约20%,造价相应降低约10%.过热蒸汽加热有投资成本小、蒸汽耗量小、热量有效利用率高的优点.并通过锅炉给水预热一次风、优化的空气预热方式等新的一次风预热思路,供不同垃圾性质、焚烧规模、控制策略等选择一次风预热形式时参考.

  4. 回转式空气预热器漏风问题的分析与对策%Analysis and Measures for Air Leakage of Rotary Air Preheater

    Institute of Scientific and Technical Information of China (English)

    夏志强; 朱新源

    2009-01-01

    大型电站锅炉广泛采用回转式空气预热器作为尾部换热设备.但是,漏风率过高是各电厂为提高经济效益需要解决的问题.通过分析分析影响漏风的因素,提出了采用双密封,安装漏风自动控制系统等降低漏风的对策.%The rotary preheater is one of the most important heat-exchange equipments in some large-sized thermal power plants. High air leakage rate, which will do much harm to the power plant, is one stubborn problem that needs to be solved to improve economic benefits. The factors influencing air leakage are analyzed, and it is suggested to adopt double seal, install air leakage automatic control system to reduce the air leakage.

  5. Preheating with fractional powers

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-11-01

    We consider preheating in models in which the potential for the inflaton is given by a fractional power, as is the case in axion monodromy inflation. We assume a standard coupling between the inflaton field and a scalar matter field. We find that in spite of the fact that the oscillation of the inflaton about the field value which minimizes the potential is anharmonic, there is nevertheless a parametric resonance instability, and we determine the Floquet exponent which describes this instability as a function of the parameters of the inflaton potential.

  6. 空气预热器烟气入口增设非平衡换热器的可行性分析%Feasibility of adding non-balance heat exchanger at gas inlet of air preheater

    Institute of Scientific and Technical Information of China (English)

    王春昌

    2014-01-01

    Against the rotating characteristics,low temperature corrosion ash deposition perform-ance and outlet gas temperature distribution rule of the rotary air preheater,it suggests non-bal-ance heat exchanger be added at the air preheater inlet and the flue duct be divided into several small ones.By properly reducing the inlet gas temperature of each small flue duct,the boiler ex-haust temperature becomes equilibrium and decreases on a whole.Finally,the boiler exhaust tem-perature can be reduced and the boiler efficiency and unit heat efficiency can be enhanced.%针对回转式空气预热器的旋转特性、低温腐蚀堵灰特征以及出口烟气温度分布规律,提出了在空气预热器入口设置非平衡换热器,将烟道分隔为几个小烟道,通过适度地降低各个小烟道的入口烟气温度,使锅炉排烟温度分布趋于平衡并整体有所降低,最终达到进一步降低锅炉排烟温度的目的,提高锅炉热效率或机组热效率。

  7. Preheating after N-flation

    CERN Document Server

    Battefeld, Diana

    2008-01-01

    We study preheating in N-flation, assuming the Mar\\v{c}enko-Pastur mass distribution, equal energy initial conditions at the beginning of inflation and equal axion-matter couplings, where matter is taken to be a single, massless bosonic field. By numerical analysis we find that preheating via parametric resonance is suppressed, indicating that the old theory of perturbative preheating is applicable. While the tensor-to-scalar ratio, the non-Gaussianity parameters and the scalar spectral index computed for N-flation are similar to those in single field inflation (at least within an observationally viable parameter region), our results suggest that the physics of preheating can differ significantly from the single field case.

  8. Investigation of optimal fluoroglass preheat

    CERN Document Server

    Baba, S; Toyoda, T; Wakamatsu, O; Machida, T

    2002-01-01

    The regular preheat condition of fluoroglass GD-301 (Chiyoda Technol Co., its size is 1.5 mm phi x 8.5 mm.) is temperature 70 deg C and time 30 minutes. When we measured dose 5.00 Gy at high energy X-ray processed with this condition, we observed build-up phenomenon according to elapsed days. So we investigated the optimal preheat temperature and time by measuring fluoroglass doses daily for several days. Fluoroglasses were irradiated 2.00 Gy of 10 MV X-ray at the reference depth using MEVATRON KD 2/50 PRIMUS (Toshiba Co.). First, we measured doses during 17 days after preheating them for 30 minutes, changing preheat temperatures from 50 deg C to 350 deg C at some intervals. Second, we measured doses during 9 days after preheating them at 70 deg C and at temperatures representing the maximum value and the most frequent value, changing preheat time from 5 minutes to 2 hours at some intervals. Doses increased up to around 115 deg C and decreased after that, and it seemed as if glasses were annealed at 350 deg C...

  9. Ventilated Double Window for the Preheating of the Ventilation Air Comparison of Its Performance in a Northern and a Southern European Climate

    Directory of Open Access Journals (Sweden)

    Jorge S. Carlos

    2013-01-01

    Full Text Available Keeping the indoor air quality within the reference levels requires that the polluted indoor air be replaced by fresh air coming from the outside. This paper presents a sensitivity analysis and a series of simulations where the performance of this passive system is studied. The influence of each relevant factor, like the wind, the solar radiation, and the outdoor air temperature, is assessed. Two different local sets of climatic data were chosen, a mild and a cold winter.

  10. Gravitational-wave mediated preheating

    Directory of Open Access Journals (Sweden)

    Stephon Alexander

    2015-04-01

    Full Text Available We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.

  11. Nonlinear Inflaton Fragmentation after Preheating

    CERN Document Server

    Felder, G N; Felder, Gary N.; Kofman, Lev

    2007-01-01

    We consider the nonlinear dynamics of inflaton fragmentation during and after preheating in the simplest model of chaotic inflation. While the earlier regime of parametric resonant particle production and the later turbulent regime of interacting fields evolving towards equilibrium are well identified and understood, the short intermediate stage of violent nonlinear dynamics remains less explored. Lattice simulations of fully nonlinear preheating dynamics show specific features of this intermediate stage: occupation numbers of the scalar particles are peaked, scalar fields become significantly non-gaussian and the field dynamics become chaotic and irreversible. Visualization of the field dynamics in configuration space reveals that nonlinear interactions generate non-gaussian inflaton inhomogeneities with very fast growing amplitudes. The peaks of the inflaton inhomogeneities coincide with the peaks of the scalar field(s) produced by parametric resonance. When the inflaton peaks reach their maxima, they stop ...

  12. Preheating with Trilinear Interactions: Tachyonic Resonance

    CERN Document Server

    Dufaux, J F; Kofman, L; Peloso, M; Podolsky, D

    2006-01-01

    We investigate the effects of bosonic trilinear interactions in preheating after chaotic inflation. A trilinear interaction term allows for the complete decay of the massive inflaton particles, which is necessary for the transition to radiation domination. We found that typically the trilinear term is subdominant during early stages of preheating, but it actually amplifies parametric resonance driven by the four-legs interaction. In cases where the trilinear term does dominate during preheating, the process occurs through periodic tachyonic amplifications with resonance effects, which is so effective that preheating completes within a few inflaton oscillations. We develop an analytic theory of this process, which we call tachyonic resonance. We also study numerically the influence of trilinear interactions on the dynamics after preheating. The trilinear term eventually comes to dominate after preheating, leading to faster rescattering and thermalization than could occur without it. Finally, we investigate the...

  13. Clinical applications of preheated hybrid resin composite.

    Science.gov (United States)

    Rickman, L J; Padipatvuthikul, P; Chee, B

    2011-07-22

    This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements.

  14. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ecton, P.A. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Beatty, J.; Verbeck, G. [Department of Chemistry, University of North Texas, Denton, TX 76203 (United States); Lakshantha, W.; Rout, B. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Perez, J.M., E-mail: jperez@unt.edu [Department of Physics, University of North Texas, Denton, TX 76203 (United States)

    2016-11-30

    Highlights: • Preheating SWCNTs in situ before irradiation prevents an increase in the D peak. • Preheated SWCNTs exposed to air or gases before irradiation show an increase in D peak. • The increase in D peak is not due to irradiation-induced chemisorption of adsorbates. • The effects are more significant for small diameter SWCNTs. • The increase in D peak is attributed to defects that increase inter-tube interactions. - Abstract: We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  15. Fuel preheater for diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Crossett, J.J.; Crossett, M.C.

    1987-10-13

    A unit for preheating fuel for diesel engines is described having an engine coolant system and a lubrication system utilizing a flowable lubricant. The unit comprises a housing providing a fluid-tight enclosure, a heat exchange coil positioned in and spaced above the bottom of the enclosure and having loops providing a continuous path for the flow of the fuel to be heated. The heat exchange coil has at least one foot of length for each 25 cubic inches of volume of the enclosure and a diesel fuel outlet in the housing connected to one end of the heat exchange coil, a diesel fuel outlet in the housing and connected to the other end of the heat exchange coil, an inlet in the housing for connection of the interior of the enclosure surrounding the coil to a source of a hot heat exchange medium in a diesel engine so as to provide a source of heat for heating the heat exchange coil. An outlet near the top of the housing provides for return of the heat exchange medium to a diesel engine, and spray tube means extend horizontally from the inlet for the heat exchange medium and along the bottom of the housing beneath substantially the entire length of the heat exchange coil. The means have upwardly directed openings to provide for discharge of the heat exchange medium toward the coil and agitation of the heat exchange medium in the enclosure around and over the heat exchange coil.

  16. Characterization of preheated and non-preheated HY-80 steel weldments by transmission electron microscopy

    OpenAIRE

    Clark, David Richard

    1983-01-01

    Approved for public release; distribution in unlimited. Preheating HY-80 steel weldments is standard procedure, but it is an expensive and time consuming step in the fabrication of hull structures. The microstructures and hardness profiles of both a preheated (250 F--121 C) and a non-preheated (32 F--0 C) HY-80 steel weldment were studied to provide information and allow comparisons of the microstructural transformations that occur in the heat affected zone during shielded metal arc weldin...

  17. Dynamics of Symmetry Breaking and Tachyonic Preheating

    CERN Document Server

    Felder, G; Greene, P B; Kofman, L A; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Garcia-Bellido, Juan; Greene, Patrick B.; Kofman, Lev; Linde, Andrei; Tkachev, Igor

    2001-01-01

    We reconsider the old problem of the dynamics of spontaneous symmetry breaking using 3d lattice simulations, and develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that symmetry breaking typically completes within a single oscillation of the field distribution as it rolls towards the minimum of its effective potential. As an application of this theory we consider preheating in the hybrid inflation scenario, including SUSY-motivated F-term and D-term inflationary models. We show that preheating in hybrid inflation is typically tachyonic and the stage of oscillations of a homogeneous component of the scalar fields driving inflation ends after a single oscillation. Our results may also be relevant for the theory of the formation of disoriented chiral condensates in heavy ion collisions.

  18. Preheating after Small-Field Inflation

    CERN Document Server

    Brax, Philippe; Mariadassou, Sophie

    2010-01-01

    Whereas preheating after chaotic and hybrid inflation models has been abundantly studied in the literature, preheating in small field inflation models, where the curvature of the inflaton potential is negative during inflation, remains less explored. In these models, a tachyonic instability at the end of inflation leads to a succession of exponentially large increases and \\emph{decreases} of the inflaton fluctuations as the inflaton condensate oscillates around the minimum of its potential. The net effect is a competition between low-momentum modes which grow and decrease significantly, and modes with higher momenta which grow less but also decrease less. We develop an analytical description of this process, which is analogous to the quantum mechanical problem of tunneling through a volcano-shaped potential. Depending on the parameters, preheating may be so efficient that it completes in less than one oscillation of the inflaton condensate. Preheating after small field inflation may also be followed by a long...

  19. Restoring the sting to metric preheating

    CERN Document Server

    Bassett, B A; Maartens, R; Kaiser, D I; Bassett, Bruce A.; Gordon, Chris; Maartens, Roy; Kaiser, David I.

    2000-01-01

    The relative growth of field and metric perturbations during preheating is sensitive to initial conditions set in the preceding inflationary phase. Recent work suggests this may protect super-Hubble metric perturbations from resonant amplification during preheating. We show that this possibility is fragile and extremely sensitive to the specific form of the interactions between the inflaton and other fields. The suppression is naturally absent in two classes of preheating in which either (1) the critical points (hence the vacua) of the effective potential during inflation are deformed away from the origin, or (2) the effective masses of fields during inflation are small but during preheating are large. Unlike the simple toy model of a g^2 \\phi^2 \\chi^2 coupling, most realistic particle physics models contain these other features. Moreover, they generically lead to both adiabatic and isocurvature modes and non-Gaussian scars on super-Hubble scales. Large-scale coherent magnetic fields may also appear naturally...

  20. Investigation on preheating process in SLS machine

    Institute of Scientific and Technical Information of China (English)

    李湘生; 史玉升; 莫健华; 黄树槐

    2001-01-01

    Selective laser sintering (SLS) is an important Rapid Prototyping method because its wide range of materials. The powder is fused and processed into a part because it is heated in the process. Preheating of powder on the surface of powder bed is a one important process which is a guarantee by which parts can be successfully fabricated and influences accuracy of parts fabricated in SLS technology. The uniformity of temperature on powder bed influences accuracy and performance of parts. It is necessary to understand the influences of the parameters of preheating set on uniformity of temperature on surface of powder bed. This paper analyzes general preheating process of irradiator for the preheating of powder on the surface of powder bed during SLS processing,and investigates influences of the flux density on the temperature field on the top surface of powder bed. The models of distribution of flux density and the distribution of surface temperature of powder bed are presented.The result predicted according to the models is reasonably consistent with experimental result. This model plays important role in design of preheating set and control of SLS processing. It is concluded that the uniformity of temperature field on the powder bed is determined mostly by the geometry of heating component and its fix location and the flux density is inverse proportional to the highness.

  1. Waste heat recovery at the glass industry with the intervention of batch and cullet preheating

    Directory of Open Access Journals (Sweden)

    Dolianitis Ioannis

    2016-01-01

    Full Text Available A promising option to reduce the specific energy consumption and CO2 emissions at a conventional natural gas fired container glass furnace deals with the advanced utilization of the exhaust gases downstream the air regenerators by means of batch and cullet preheating. A 3-dimensional computational model that simulates this process using mass and heat transfer equations inside a preheater has been developed. A case study for an efficient small-sized container glass furnace is presented dealing with the investigation of the impact of different operating and design configurations on specific energy consumption, CO2 emissions, flue gas energy recovery, batch temperature and preheater efficiency. In specific, the effect of various parameters is studied, including the preheater’s dimensions, flue gas temperature, batch moisture content, glass pull, combustion air excess and cullet fraction. Expected energy savings margin is estimated to 12-15%.

  2. The Development of Equilibrium After Preheating

    CERN Document Server

    Kofman, L A

    2001-01-01

    We present a fully nonlinear study of the development of equilibrium after preheating. Preheating is the exponentially rapid transfer of energy from the nearly homogeneous inflaton field to fluctuations of other fields and/or the inflaton itself. This rapid transfer leaves these fields in a highly nonthermal state with energy concentrated in infrared modes. We have performed lattice simulations of the evolution of interacting scalar fields during and after preheating for a variety of inflationary models. We have formulated a set of generic rules that govern the thermalization process in all of these models. Notably, we see that once one of the fields is amplified through parametric resonance or other mechanisms it rapidly excites other coupled fields to exponentially large occupation numbers. These fields quickly acquire nearly thermal spectra in the infrared, which gradually propagates into higher momenta. Prior to the formation of total equilibrium, the excited fields group into subsets with almost identica...

  3. Temperature equilization in the Luetzkendorf preheater

    Energy Technology Data Exchange (ETDEWEB)

    1943-01-30

    Suggestions are offered for improvement to attain more nearly uniform temperature distribution in the preheater inlet and outlet as well as for improvement of a loss of pressure in heating gas for raising the efficiency of the heating gas blower. The evaluation of the operating conditions from the standpoint of the heating gas were made in the hydrogenation works of Poelitz, in 1939 with the preheater constructed on the Ludwigshafen plan, and in Luetzkendorf on the preheater of the Leuna model. Both preheaters had two Schiele heating gas blowers of the type 1160. Operating conditions involving hairpin tubes, temperatures, resistance, volume, piping, pressure, and heat conduction were given for both plants. A sketch for the heating gas movement was mentioned in the report but was not included. Recommendations on the use of a new blower were given. Some of these were reducing the yield to 90,000 cubic meters per hour and using the same motors. The distribution of the amounts and of the temperature drop of the gas and of the material of the hairpins were given.

  4. Research on a Household Dual Heat Source Heat Pump Water Heater with Preheater Based on ASPEN PLUS

    Directory of Open Access Journals (Sweden)

    Xiang Gou

    2016-12-01

    Full Text Available This article proposes a dual heat source heat pump bathroom unit with preheater which is feasible for a single family. The system effectively integrates the air source heat pump (ASHP and wastewater source heat pump (WSHP technologies, and incorporates a preheater to recover shower wastewater heat and thus improve the total coefficient of performance (COP of the system, and it has no electric auxiliary heating device, which is favorable to improve the security of the system operation. The process simulation software ASPEN PLUS, widely used in the design and optimization of thermodynamic systems, was used to simulate various cases of system use and to analyze the impact of the preheater on the system. The average COP value of a system with preheater is 6.588 and without preheater it is 4.677. Based on the optimization and analysis, under the standard conditions of air at 25 °C, relative humidity of 70%, wastewater at 35 °C, wastewater flow rate of 0.07 kg/s, tap water at 15 °C, and condenser outlet water temperature at 50 °C, the theoretical COP of the system can reach 9.784 at an evaporating temperature of 14.96 °C, condensing temperature of 48.74 °C, and preheated water temperature of 27.19 °C.

  5. Recent Advances in Electrical Resistance Preheating of Aluminum Reduction Cells

    Science.gov (United States)

    Ali, Mohamed Mahmoud; Kvande, Halvor

    2017-02-01

    There are two mainpreheating methods that are used nowadays for aluminum reduction cells. One is based on electrical resistance preheating with a thin bed of small coke and/or graphite particles between the anodes and the cathode carbon blocks. The other is flame preheating, where two or more gas or oil burners are used. Electrical resistance preheating is the oldest method, but is still frequently used by different aluminum producers. Many improvements have been made to this method by different companies over the last decade. In this paper, important points pertaining to the preparation and preheating of these cells, as well as measurements made during the preheating process and evaluation of the performance of the preheating, are illustrated. The preheating times of these cells were found to be between 36 h and 96 h for cell currents between 176 kA and 406 kA, while the resistance bed thickness was between 13 mm and 60 mm. The average cathode surface temperature at the end of the preheating was usually between 800°C and 950°C. The effect of the preheating methods on cell life is unclear and no quantifiable conclusions can be drawn. Some works carried out in the mathematical modeling area are also discussed. It is concluded that there is a need for more studies with real situations for preheated cells on the basis of actual measurements. The expected development in electrical resistance preheating of aluminum reduction cells is also summarized.

  6. Pre-heating mitigates composite degradation.

    Science.gov (United States)

    Silva, Jessika Calixto da; Rogério Vieira, Reges; Rege, Inara Carneiro Costa; Cruz, Carlos Alberto dos Santos; Vaz, Luís Geraldo; Estrela, Carlos; Castro, Fabrício Luscino Alves de

    2015-01-01

    Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey's tests (α=5%). Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (pheated specimens presented higher radiopacity values than non-pre-heated specimens (pheated specimens (pheating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  7. Violent Preheating in Inflation with Nonminimal Coupling

    CERN Document Server

    Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori

    2016-01-01

    We study particle production at the preheating era in inflation models with nonminimal coupling $\\xi \\phi^2R$ and quartic potential $\\lambda \\phi^4/4$ for several cases: real scalar inflaton, complex scalar inflaton and Abelian Higgs inflaton. We point out that the preheating proceeds much more violently than previously thought. If the inflaton is a complex scalar, the phase degree of freedom is violently produced at the first stage of preheating. If the inflaton is a Higgs field, the longitudinal gauge boson production is similarly violent. This is caused by a spike-like feature in the time dependence of the inflaton field, which may be understood as a consequence of short time scale during which the effective potential or kinetic term changes suddenly. The produced particles typically have very high momenta $k \\lesssim \\sqrt{\\lambda}M_\\text{P}$. The production might be so strong that almost all the energy of the inflaton is carried away within one oscillation for $\\xi^2\\lambda \\gtrsim 1$. This may significa...

  8. Spectroscopic Measurements of Target Preheating on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Elton, R.C.; Griem, H.R.; Iglesias, E.J.

    2000-02-28

    The preheating of laser-heated microballoon targets has been measured by time-resolved x-ray and extreme ultraviolet (euv) spectroscopy on the 30 kJ, 351 nm, 60-beam laser-fusion system at the University of Rochester Laboratory for Laser Energetics. Thin coatings of aluminum overcoated with magnesium served as indicators. both the sequence of the x-ray line emission and the intensity of euv radiation were used to determine a preheating peaking at {approx} 10 ns prior to onset of the main laser pulse, with a power density {approx_equal}1% of the main pulse. The measurements are supported by numerical modeling. Further information is provided by absorption spectra from the aluminum coating, backlighted by continuum from the heated surface. The exact source of the preheating energy remains unknown at present, but most likely arrives from early laser leakage through the system. The present target diagnostic is particularly useful when all beams cannot be monitored directly at all laser wavelengths.

  9. Metric-torsion preheating: cosmic dynamo mechanism?

    CERN Document Server

    de Andrade, L C Garcia

    2014-01-01

    Earlier Bassett et al [Phys Rev D 63 (2001) 023506] investigated the amplification of large scale magnetic fields during preheating and inflation in several different models. They argued that in the presence of conductivity resonance effect is weakened. From a dynamo equation in spacetimes endowed with torsion recently derived by Garcia de Andrade [Phys Lett B 711: 143 (2012)] it is shown that a in a universe with pure torsion in Minkowski spacetime the cosmological magnetic field is enhanced by ohmic or non-conductivity effect, which shows that the metric-torsion effects is worth while of being studied. In this paper we investigated the metric-torsion preheating perturbation, which leads to the seed cosmological magnetic field in the universe with torsion is of the order of $B_{seed}\\sim{10^{-37}Gauss}$ which is several orders of magnitude weaker than the decoupling value obtained from pure metric preheating of $10^{-15}Gauss$. Despite of the weakness of the magnetic field this seed field may seed the galact...

  10. Effect of preheating on potato texture.

    Science.gov (United States)

    Andersson, A; Gekas, V; Lind, I; Oliveira, F; Oste, R

    1994-01-01

    Preheating potatoes at 50 to 80 degrees C has a firming effect on the cooked potato tissue. This effect is particularly pronounced at a preheating temperature of 60 to 70 degrees C followed by cooling. Several theories have been presented in the literature to explain this firming effect: retrogradation of starch, leaching of amylose, stabilization of the middle lamellae and cell walls by the activation of the pectin methylesterase (PME) enzyme, and by the release of calcium from gelatinized starch and the formation of calcium bridges between pectin molecules. Most probably, none of these theories alone can explain the phenomenon and more than one mechanism seems to be involved. Some of these mechanisms seem to be interdependent. As an example, calcium could be considered as a link all the way through release after starch gelatinization to cross-linking pectin substances in the cell wall and the middle lamellae, which has been demethylated by the PME enzyme. More research and "clear cut" experiments are needed in order to elucidate the role of each mechanism, especially which of them is the main contributor to the process of firming. Most probably, the calcium-pectin-PME mechanism plays a secondary role, that is, it only retards the collapse of the tissue structure that would otherwise occur during the final heating without preheating, and it is not the main factor of firmness.

  11. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Science.gov (United States)

    Ecton, P. A.; Beatty, J.; Verbeck, G.; Lakshantha, W.; Rout, B.; Perez, J. M.

    2016-11-01

    We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  12. 燃料稀释对传统型和高预热空气稀释型燃烧炉性能的影响的数值研究%Numerical Investigation of Fuel Dilution Effects on the Performance of the Conventional and the Highly Preheated and Diluted Air Combustion Furnaces

    Institute of Scientific and Technical Information of China (English)

    Kiomars Abbasi Khazaei; Ali Asghar Hamidi; Masoud Rahimi

    2009-01-01

    This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N_2) in an industrial furnace under several cases of conventional combustion (air with 21% O_2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O_2 and 90% N_2) combustion (HPDAC) conditions using an in-house computer program. It was found that by applying a combined diluted fuel and oxidant instead of their un-combined and/or undiluted states, the best condition is obtained for the establishment of HPDAC's main unique features. These features are low mean and maximum gas temperature and high radiation/total heat transfer to gas and tubes; as well as more uniformity of theirs distributions which results in decrease in NO_x pollutant formation and increase in furnace efficiency or energy saving. Moreover, a variety of chemical flame shape, the process fluid and tubes walls temperatures profiles, the required regenerator efficiency and finally the concentration and velocity patterns have been also qualitatively/quantitatively studied.

  13. Aspects of wave turbulence in preheating

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Henrique P. de; Crespo, Jose A. de A. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Full text: In the simplest chaotic inflationary model, the Universe has an exponentially fast expansion phase driven by a single scalar field. After inflation, the preheating phase takes place. This phase is characterized when the inflaton performs coherent oscillations about its minimum value and is followed by a huge production of particles. In other terms, there is an energy transfer to small inhomogeneous fluctuations of the inflaton field. The long term behavior ends up in a thermalized universe. In this paper, we have studied numerically the late stages of preheating in a model with a quartic potential V (ϕ) = ¼λ ϕ{sup 4}. We have considered the universe as a squared box with periodic boundary conditions, and applied the collocation method to integrate the field equations. We have shown that the dynamics of the inflaton together with its initially small fluctuations is extremely rich. In the first stage, the parametric resonance is responsible for the exponential growth of some modes. In the sequence, the back reaction of these resonant modes triggers the transfer of energy to other modes or fluctuations. Subsequently, the transfer of energy from the inflaton to thermalize the universe is typical of a turbulent system. In the last part, we have considered the back reaction of the inflaton field in the expansion of the universe. (author)

  14. Experimental study on preheated combustion of pulverized semi-coke

    Science.gov (United States)

    Yao, Yao; Zhu, Jianguo; Lu, Qinggang; Zhou, Zuxu

    2015-06-01

    In a test rig, pulverized semi-coke was preheated to 850oC in a circulating fluidized bed (CFB) and then combusted at 1100oC in a down-fired combustor (DFC). Experiments were conducted to reveal the effects of three secondary air nozzle cases (co-axial jet, top circular jet and wall circular jet) on the NO emission. The results show that the optimized secondary air nozzle can reduce NO emission. O2 concentration profile is the major factor affecting NO generation and emission, which is led by the secondary air nozzle. The lower O2 concentration led to the generation of lower initial NO. The NO emission at the exit of the DFC was reduced from 189 to 92 mg/m3 (@ 6% O2) with the decrease of initial generation. The peak of NO at 100 mm below the nozzle should be attributed to the oxidization of NH3 in the syngas, rather than the oxidization of fuel-N in the char. The low and well-distributed O2 concentration contributes to the reduction of initial NO, which helps to reduce the NO emission. The combustion efficiencies of the cases of the co-axial jet, the top circular jet, and the wall circular jet are 97.88%, 98.94% and 98.74%, respectively.

  15. Preheating Cold Gas Thruster Flow Through a Thermal Energy Storage Conversion System

    Science.gov (United States)

    2013-01-01

    Journal Article 3. DATES COVERED (From - To) January 2013- October 2013 4. TITLE AND SUBTITLE Preheating Cold Gas Thruster Flow Through a Thermal Energy... Gas Thruster Flow through a Thermal Energy Storage Conversion System Michael R. Reid1 United States Air Force, Colorado Springs, CO, 80840 David B...specific impulse relative to a cold gas flow. Electric propulsion systems, the primary competitor to solar thermal propulsion systems, rely on the rather

  16. Ions Preheated in 3He-Rich Solar Particle Events

    Institute of Scientific and Technical Information of China (English)

    王德焴

    2003-01-01

    A wave-particle resonance absorption model in the two-ion plasma is suggested in explanation to the coronal ions preheating in 3He-rich solar particle events. It is found that 3He and Fe ions are preferably preheated by the ion-ion hybrid waves at their fundamental and second harmonic ion cyclotron frequencies, respectively.

  17. QUENCH STUDIES AND PREHEATING ANALYSIS OF SEAMLESS

    Energy Technology Data Exchange (ETDEWEB)

    Palczewski, Ari [JLAB; Geng, Rongli [JLAB; Eremeev, Grigory [JLAB

    2013-09-01

    One of the alternative manufacturing technologies for SRF cavities is hydroforming from seamless tubes. Although this technology has produced cavities with gradient and Q-values comparable to standard EBW/EP cavities, a few questions remain. One of these questions is whether the quench mechanism in hydroformed cavities is the same as in standard electron beam welded cavities. Towards this effort Jefferson Lab performed quench studies on 2 9 cell seamless hydroformed cavities. These cavities include DESY's - Z163 and Z164 nine-cell cavities hydroformed at DESY. Initial Rf test results Z163 were published in SRF2011. In this report we will present post JLAB surface re-treatment quench studies for each cavity. The data will include OST and T-mapping quench localization as well as quench location preheating analysis comparing them to the observations in standard electron beam welded cavities.

  18. Fate of Electroweak Vacuum during Preheating

    CERN Document Server

    Ema, Yohei; Nakayama, Kazunori

    2016-01-01

    Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible dynamics that might relax them.

  19. EFFECT OF STORAGE, PRE-HEATING AND TURNING DURING HOLDING PERIOD ON THE HATCHABILITY OF BROILER BREEDER EGGS

    Directory of Open Access Journals (Sweden)

    A. MAHMUD AND T. N. PASHA1

    2008-07-01

    Full Text Available Two hundred forty fertile eggs of an average weight of 52-55g were taken from 32 weeks old broiler breeder flock. These eggs were divided into four groups i.e. A (Without turning and preheating, B (No turning but preheated, C (Turned but without preheating, and D (given both treatments preheating and turning with 60 eggs in each group. The eggs were stored with broad end upward at 16-20°C and 65-75% humidity. After storage for 5 days, the pre-heating of eggs of groups B and D was performed in an incubator where hot air at 30°C temperature was circulated for 6-7 hours to provide gradual warmth to the eggs before setting in the same incubator. The temperature of the incubator was maintained at 37.6°C with relative humidity of 70%. The eggs of groups C and D were turned on hourly basis at an angle of about 45° till 17 days of incubation. The hatchability values of eggs of groups A, B, C and D were 88.30 ± 0.30, 76.30 ± 0.30, 83.30 ± 0.30 and 79.90 ± 0.10%, respectively. Statistical analysis of the data by Chi-square test showed non-significant differences among treatments.

  20. Hill crossing during preheating after hilltop inflation

    CERN Document Server

    Antusch, Stefan; Orani, Stefano

    2015-01-01

    In 'hilltop inflation', inflation takes place when the inflaton field slowly rolls from close to a maximum of its potential (i.e. the 'hilltop') towards its minimum. When the inflaton potential is associated with a phase transition, possible topological defects produced during this phase transition, such as domain walls, are efficiently diluted during inflation. It is typically assumed that they also do not reform after inflation, i.e. that the inflaton field stays on its side of the 'hill', finally performing damped oscillations around the minimum of the potential. In this paper we study the linear and the non-linear phases of preheating after hilltop inflation. We find that the fluctuations of the inflaton field during the tachyonic oscillation phase grow strong enough to allow the inflaton field to form regions in position space where it crosses 'over the top of the hill' towards the 'wrong vacuum'. We investigate the formation and behaviour of these overshooting regions using lattice simulations: Rather t...

  1. Application of the Separate Universe Approach to Preheating

    CERN Document Server

    Tanaka, T; Tanaka, Takahiro; Bassett, Bruce

    2003-01-01

    The dynamics of preheating after inflation has not been clearly understood yet.In particular, the issue of the generation of metric perturbations during preheating on super-horizon scale is still unsettled. Large scale perturbations may leave an imprint on the cosmic microwave background, or may become seeds for generation of primordial black holes. Hence, in order to make a connection between the particle physics models and cosmological observations, understanding the evolution of super-Hubble scale perturbations during preheating is important. Here, we propose an alternative treatment to handle this issue based on the so-called separate universe approach, which suggests less efficient amplification of super-Hubble modes during preheating than was expected before. We also point out an important issue which may have been overlooked in previous treatments.

  2. Equation of state and Beginning of Thermalization After Preheating

    CERN Document Server

    Podolsky, D I; Kofman, L; Peloso, M; Podolsky, Dmitry I.; Felder, Gary N.; Kofman, Lev; Peloso, Marco

    2006-01-01

    We study the out-of-equilibrium nonlinear dynamics of fields after post-inflationary preheating. During preheating, the energy in the homogeneous inflaton is exponentially rapidly transfered into highly occupied out-of-equilibrium inhomogeneous modes, which subsequently evolve towards equilibrium. The infrared modes excited during preheating evolve towards a saturated distribution long before thermalization completes. We compute the equation of state during and immediately after preheating. It rapidly evolves towards radiation domination long before the actual thermal equilibrium is established. The exact time of this transition is a non-monotonic function of the coupling between the inflaton and the decay products, and it varies only very weakly (around 10^(-35) s) as this coupling changes over several orders of magnitude. This result is applied to refine the relation between the number of efoldings N and the physical wavelength of perturbations generated during inflation. We also discuss the implications fo...

  3. Anisotropies in the gravitational wave background from preheating.

    Science.gov (United States)

    Bethke, Laura; Figueroa, Daniel G; Rajantie, Arttu

    2013-07-05

    We investigate the anisotropies in the gravitational wave (GW) background produced at preheating after inflation. Using lattice field theory simulations of a massless preheating model, we show that the GW amplitude depends sensitively on the value of the decay product field χ coupled to the inflaton φ, with the only requisite that χ is light during inflation. We find a strong anisotropy in the amplitude of the GW background on large angular scales, the details of which strongly depend on the reheating dynamics. We expect similar conclusions for a wide class of inflationary models with light scalar fields. If future direct detection GW experiments are capable of detecting the GW produced by preheating, they should also be able to detect this effect. This could eventually provide a powerful way to distinguish between different inflationary and preheating scenarios.

  4. Gauge Field Preheating at the End of Inflation

    CERN Document Server

    Deskins, J Tate; Caldwell, Robert R

    2013-01-01

    Here we consider the possibility of preheating the Universe via the parametric amplification of a massless, U(1) abelian gauge field. We assume that the gauge field is coupled to the inflaton via a conformal factor with one free parameter. We present the results of high-resolution three-dimensional simulations of this model and show this mechanism efficiently preheats the Universe to a radiation-dominated final state.

  5. Reheating and preheating in the simplest extension of Starobinsky inflation

    CERN Document Server

    van de Bruck, C; Paduraru, L E

    2016-01-01

    The epochs of reheating and preheating are studied in a simple extension of the Starobinsky inflationary model, which consists of an $R^2$--correction to the Einstein--Hilbert action and an additional scalar field. We find that if the $R^2$--correction at the end of inflation is dynamically important, it affects the expansion rate and as a consequence the reheating and preheating processes. While we find that the reheating temperature and duration of reheating are only slightly affected, the effect has to be taken into account when comparing the theory to data. In the case of preheating, the gravitational corrections can significantly affect the decay of the second field. Particle production is strongly affected for certain values of the parameters in the theory.

  6. Gravity Waves from Tachyonic Preheating after Hybrid Inflation

    CERN Document Server

    Dufaux, Jean Francois; Kofman, Lev; Navros, Olga

    2008-01-01

    We study the stochastic background of gravitational waves produced from preheating in hybrid inflation models. We investigate different dynamical regimes of preheating in these models and we compute the resulting gravity wave spectra using analytical estimates and numerical simulations. We discuss the dependence of the gravity wave frequencies and amplitudes on the various potential parameters. We find that large regions of the parameter space leads to gravity waves that may be observable in upcoming interferometric experiments, including Advanced LIGO, but this generally requires very small coupling constants.

  7. Formation of sub-horizon black holes from preheating

    CERN Document Server

    Torres-Lomas, E; Malik, Karim A; Ureña-López, L Arturo

    2014-01-01

    We study the production of primordial black holes (PBHs) during the preheating stage that follows a chaotic inflationary phase. The scalar fields present in the process are evolved numerically using a modified version of the HLATTICE code. From the output of the numerical simulation we compute the probability distribution of curvature fluctuations paying particular attention to sub-horizon scales. We find that in some specific models these modes grow to large amplitudes developing highly non-Gaussian probability distributions. We then calculate PBH abundances using the standard Press-Schechter criterion and find that overproduction of PBHs is likely in some regions of the chaotic preheating parameter-space.

  8. Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

    Science.gov (United States)

    Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

    2012-06-01

    In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

  9. Analysis of sodium experimental circuits pre-heating for the development of nuclear reactors; Analise do pre-aquecimento de circuitos experimentais a sodio para desenvolvimento de reatores nuclares

    Energy Technology Data Exchange (ETDEWEB)

    Bellini, Ione Walmir

    1995-09-01

    To satisfy the experimental requirements of sodium loops for nuclear reactors development, a preheating system, consisting of tubular haters, is analyzed. The tubular heaters are usually comprised of a nickel-chromium wire centered in a metal sheath and insulated by magnesium oxide. Practical and simplified methods for the preheating parameters calculations and for the heaters elements determination and section are presented. A thermal method to evaluate the sodium mass in a tank is presented, using the preheating system, when the tank geometry or the sodium level are unknown. The materials employed and the installation procedures of the preheating system are indicated. It is described a procedure, step, to make the connection between the electrical resistance and the conductor wire, to assure the heat dissipation and the air-tight of the heater element. Several suggestions are presented to clarify some doubts, to define correction factors, to develop technology, and to give continuity to the present work. (author). 37 refs., 22 figs.

  10. Theory and Numerics of Gravitational Waves from Preheating after Inflation

    CERN Document Server

    Dufaux, Jean Francois; Felder, Gary N; Kofman, Lev; Uzan, Jean-Philippe

    2007-01-01

    Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast our method with other numerical methods in the literature, and then we apply it to preheating after chaotic inflation. In this case, we are able to check analytically our numerical results, which differ significantly from previous works. We discuss how the gravity wave spectrum builds up with time and find that the amplitude an...

  11. A Model Independent Approach to (p)Reheating

    CERN Document Server

    Özsoy, Ogan; Sinha, Kuver; Watson, Scott

    2015-01-01

    In this note we propose a model independent framework for inflationary (p)reheating. Our approach is analogous to the Effective Field Theory of Inflation, however here the inflaton oscillations provide an additional source of (discrete) symmetry breaking. Using the Goldstone field that non-linearly realizes time diffeormorphism invariance we construct a model independent action for both the inflaton and reheating sectors. Utilizing the hierarchy of scales present during the reheating process we are able to recover known results in the literature in a simpler fashion, including the presence of oscillations in the primordial power spectrum. We also construct a class of models where the shift symmetry of the inflaton is preserved during reheating, which helps alleviate past criticisms of (p)reheating in models of Natural Inflation. Extensions of our framework suggest the possibility of analytically investigating non-linear effects (such as rescattering and back-reaction) during thermalization without resorting t...

  12. Preheating and Affleck-Dine leptogenesis after thermal inflation

    CERN Document Server

    Felder, G N; Park, W I; Stewart, E D; Felder, Gary N.; Kim, Hyunbyuk; Park, Wan-Il; Stewart, Ewan D.

    2007-01-01

    Previously, we proposed a model of low energy Affleck-Dine leptogenesis in the context of thermal inflation. The lepton asymmetry is generated at the end of thermal inflation, which occurs at a relatively low energy scale with the Hubble parameter somewhere in the range $1 \\keV \\lesssim H \\lesssim 1 \\MeV$. Thus Hubble damping will be ineffective in bringing the Affleck-Dine field into the lepton conserving region near the origin, leaving the possibility that the lepton number could be washed out. Previously, we suggested that preheating could damp the amplitude of the Affleck-Dine field allowing conservation of the lepton number. In this paper, we demonstrate numerically that preheating does efficiently damp the amplitude of the Affleck-Dine field and that the lepton number is conserved as the result. In addition to demonstrating a crucial aspect of our model, it also opens the more general possibility of low energy Affleck-Dine baryogenesis.

  13. Bruce Unit 1 and 2 preheater condition assessment and refurbishment

    Energy Technology Data Exchange (ETDEWEB)

    King, P.; Machowski, C.; McGillivray, R. [Babcock and Wilcox Canada Ltd., Cambridge, ON (Canada); Durance, D. [Bruce Power, Tiverton, ON (Canada)

    2008-07-01

    Bruce Units 1 to 4 were shut down during the 1990s, largely as a consequence of tube degradation resulting from inappropriate steam generator secondary side water chemistries. Following a condition assessment, Bruce Power restarted Units 3 and 4 and is currently refurbishing Units 1 and 2. In order to assess the condition of the Unit 1 and Unit 2 preheaters and determine their suitability for extended operation, inspection, maintenance and assessment activities have been conducted. Eddy current and visual inspection have revealed vessels in generally good condition. Secondary side internals appear largely undergraded. Some tube to support fretting has been observed, and a number of tubes have been removed from service because of debris fretting concerns. To prepare for return to service, the primary side divider plates have been replaced and the tubes have been ID cleaned to restore the preheater to its original condition. This paper summarizes the inspection planning, findings, assessment for extended operation and maintenance activities undertaken. (author)

  14. Non-equilibrium Goldstone phenomenon in tachyonic preheating

    CERN Document Server

    Borsanyi, S; Sexty, D; Borsanyi, Sz.

    2003-01-01

    The dominance of the direct production of elementary Goldstone waves is demonstrated in tachyonic preheating by determining numerically the evolution of the dispersion relation, the equation of state and the kinetic power spectra for the angular degree of freedom of the complex matter field. The importance of the domain structure in the order parameter distribution for the quantitative understanding of the excitation mechanism is emphasized. Evidence is presented for the very early decoupling of the low-momentum Goldstone modes.

  15. Gauge-preheating and the end of axion inflation

    CERN Document Server

    Adshead, Peter; Scully, Timothy R; Sfakianakis, Evangelos I

    2015-01-01

    We study the onset of the reheating epoch at the end of axion-driven inflation where the axion is coupled to an Abelian, $U(1)$, gauge field via a Chern-Simons interaction term. We focus primarily on $m^2\\phi^2$ inflation and explore the possibility that preheating can occur for a range of coupling values consistent with recent observations and bounds on the overproduction of primordial black holes. We find that for a wide range of parameters preheating is efficient. In certain cases the inflaton is seen to transfer all its energy to the gauge fields within a few oscillations. We find that the gauge fields on sub-horizon scales end in an unpolarized state, due to the existence of strong rescattering between the inflaton and gauge modes. We also present a preliminary study of an axion monodromy model coupled to $U(1)$ gauge fields, seeing a similarly efficient preheating behavior as well as indications that the coupling strength has an effect on the creation of oscillons.

  16. Preheating and Entropy Perturbations in Axion Monodromy Inflation

    CERN Document Server

    ,

    2016-01-01

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index $n_s = 5/2$. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  17. Preheating and entropy perturbations in axion monodromy inflation

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, Evan; Moghaddam, Hossein Bazrafshan [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Brandenberger, Robert H. [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Institute for Theoretical Studies, ETH Zürich,CH-8092 Zürich (Switzerland)

    2016-05-04

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index n{sub s}=5/2. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  18. Low SO2 Emission Preheaters for Cement Production

    DEFF Research Database (Denmark)

    Rasmussen, Martin Hagsted

    Themost common way of producing cement today is effected through what is known as the dry process. If the raw materials used in this process contain sulphide, the plant layout can lead to emissions of SO2 from the preheater tower. SO2 emissions are most often caused by the oxidation of pyritic...... showed that this figure could be between 90 kJ/mole and 140 kJ/mole, with a corresponding change of preexponential factors. The ability to predict emissions is very important in the design of cement plants. In this thesis the zone model concept has been applied to the modelling of the cyclone stages...

  19. Measuring preheat in laser-drive aluminum using velocity interferometer system for any reflector: Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Hua; Fu, Sizu; Huang, Xiuguang; Wu, Jiang; Xie, Zhiyong; Zhang, Fan; Ye, Junjian; Jia, Guo; Zhou, Huazhen [Shanghai Institute of Laser Plasma, P.O. BOX 800-229, Shanghai 201800 (China)

    2014-08-15

    In this paper, we systematically study preheating in laser-direct-drive shocks by using a velocity interferometer system for any reflector (VISAR). Using the VISAR, we measured free surface velocity histories of Al samples over time, 10–70 μm thick, driven directly by a laser at different frequencies (2ω, 3ω). Analyzing our experimental results, we concluded that the dominant preheating source was X-ray radiation. We also discussed how preheating affected the material initial density and the measurement of Hugoniot data for high-Z materials (such as Au) using impedance matching. To reduce preheating, we proposed and tested three kinds of targets.

  20. Higgs vacuum metastability in primordial inflation, preheating, and reheating

    Science.gov (United States)

    Kohri, Kazunori; Matsui, Hiroki

    2016-11-01

    Current measurements of the Higgs boson mass and top Yukawa coupling suggest that the effective Higgs potential develops an instability below the Planck scale. If the energy scale of inflation is as high as the grand unified theory (GUT) scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum and produce a lot of anti-de Sitter (AdS) domains. This destabilization during inflation can be avoided if a relatively large nonminimal Higgs-gravity or inflaton-Higgs coupling is introduced. Such couplings generate a large effective mass term for the Higgs, which can raise the effective Higgs potential and suppress the vacuum fluctuation of the Higgs field. After primordial inflation, however, such effective masses drops rapidly and the nonminimal Higgs-gravity or inflaton-Higgs coupling can cause large fluctuations of the Higgs field to be generated via parametric resonance, thus producing AdS domains in the preheating stage. Furthermore, thermal fluctuations of the Higgs field cannot be neglected in the proceeding reheating epoch. We discuss the Higgs vacuum fluctuations during inflation, preheating, and reheating, and show that the Higgs metastability problem is severe unless the energy scale of the inflaton potential is much lower than the GUT scale.

  1. Microstructures and properties of non-preheated hardfacing welding

    Institute of Scientific and Technical Information of China (English)

    Yang Shanglei; Zou Zengda; Lü Xueqin; Lou Songnian

    2007-01-01

    A new type of non-preheated hardfacing electrode was developed using H08A as the core and the coat contents including ferrotitanium, ferrovanadium, graphite, rutile etc. The microstructures and properties of hardfacing metal were systematically researched. The results show the hardness of hardfacing metal increases with increasing of ferrotitanium, ferrovanadium, graphite in the coat, but the crack resistance and processing weldability become worse. The carbides formed by arc metallurgic reaction are uniformly dispersed in the matrix structure. The phases of hardfacing metal consist of α-Fe, γ-Fe, VC, TiC and Fe3C. The carbides are compression aggregation of TiC and VC, and their appearances present irregular block. The matrix microstructure of hardfacing metal is lath martensite. The hardfacing layers with better crack resistance and wearability are achieved and no visible cracks occur when using non-preheated electrode in continuous welding process. Hardness of hardfacing metal is more than 60HRC, and its relative wearability is five times of wearability of D667 electrode in abrasive wear test.

  2. Corrosion leaking of preheater weldment in alumina factories

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CHEN Wen-mi; GONG Zhu-qing; LIU Hong-zhao

    2005-01-01

    Stress corrosion cracking (SCC) and anticorrosion measures of TU42C weld-joint were studied by constant load experiments and pickling experiments. The results show that in 40%(mass fraction) NaOH solution at 110 ℃, caustic SCC occurs in TU42C weld-joints at the applied potential of -1 020 mV(vs SCE) for 3 d while at the potential of -950 mV(vs SCE) for 10 d. All the cracks are intergranular. In the 10% sulfuric acid, the cracks have the most negative self-corrosion potential -432.5 mV(vs SCE) and are active to be further corroded by the acid. Because of the same corrosion behaviour as the lab weldment, preheater's cracking in alumina factories is attributed to the combining actions of previous caustic SCC in Bayer solutions and continuous acid corrosion by pickling with the addition of RD. The following measures are effective to prevent the corrosion failure of preheater, such as postweld heat treatment at 620 ℃ to relax the residual weld stress, addition of CC3 and L826 as the corrosion inhibitors to improve the pickling and cleaning by the high pressure water instead of by pickling.

  3. Production of biohydrogen from hydrolyzed bagasse with thermally preheated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Chairattanamanokorn, Prapaipid [Environmental Technology Unit, Department of Environmental Science, Kasetsart University, Bangkok (Thailand); Research Group for Development of Microbial Hydrogen Production Process from Biomass (Thailand); Penthamkeerati, Patthra [Environmental Technology Unit, Department of Environmental Science, Kasetsart University, Bangkok (Thailand); Reungsang, Alissara [Research Group for Development of Microbial Hydrogen Production Process from Biomass (Thailand); Department of Biotechnology, Khon Kaen University, Khon Kaen, Bangkok (Thailand); Lo, Yung-Chung [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Lu, Wei-Bin [Department of Cosmetic Science, Chung Hwa University of Medical Technology, Tainan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China)

    2009-09-15

    Production of biohydrogen from dark fermentation is an interesting alternative to producing renewable fuels because of its low cost and various usable substrates. Cellulosic content in plentiful bagasse residue is an economically feasible feedstock for biohydrogen production. A statistical experimental design was applied to identify the optimal condition for biohydrogen production from enzymatically hydrolyzed bagasse with 60-min preheated seed sludge. The bagasse substrate was first heated at 100 C for 2 h and was then hydrolyzed with cellulase. Culture of the pretreated bagasse at 55 C provided a higher H{sub 2} production performance than that obtained from cultures at 45 C, 65 C, 35 C and 25 C. On the other hand, the culture at pH 5 resulted in higher H{sub 2} production than the cultures at pH 6, pH 4 and pH 7. The optimal culture condition for the hydrogen production rate was around 56.5 C and pH 5.2, which was identified using response surface methodology. Moreover, the pretreatment of bagasse under alkaline conditions gave a thirteen-fold increase in H{sub 2} production yield when compared with that from preheatment under neutral condition. (author)

  4. Pre-heating in the framework of massive gravity

    Directory of Open Access Journals (Sweden)

    Debaprasad Maity

    2016-09-01

    Full Text Available In this paper we propose a mechanism of natural pre-heating of our universe by introducing an inflaton field dependent mass term for the gravitational wave for a specific class of massive gravity theory. For any single field inflationary model, the inflaton must go through the oscillatory phase after the end of inflation. As has recently been pointed out, if the gravitational fluctuation has inflaton dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflaton. Because of this large enhancement of the amplitude of the gravitational wave due to parametric resonance, we show that universe can naturally go through the pre-reheated phase with minimally coupled matter field. Therefore, during the reheating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflaton.

  5. Frustration of resonant preheating by exotic kinetic terms

    Energy Technology Data Exchange (ETDEWEB)

    Rahmati, Shohreh; Seahra, Sanjeev S., E-mail: srahmati@unb.ca, E-mail: sseahra@unb.ca [Department of Mathematics and Statistics, University of New Brunswick, Fredericton, NB, E3B 5A3 Canada (Canada)

    2014-10-01

    We study the effects of exotic kinetic terms on parametric resonance during the preheating epoch of the early universe. Specifically, we consider modifications to the action of ordinary matter fields motivated by generalized uncertainty principles, polymer quantization, as well as Dirac-Born-Infeld and k-essence models. To leading order in an ''exotic physics'' scale, the equations of motion derived from each of these models have the same algebraic form involving a nonlinear self-interaction in the matter sector. Neglecting spatial dependence, we show that the nonlinearity effectively shuts down the parametric resonance after a finite time period. We find numeric evidence that the frustration of parametric resonance persists to spatially inhomogenous matter in (1+1)-dimensions.

  6. 20 YEARS OF EXPERIENCE WITH SCRAP PREHEATING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Je. Apfel

    2015-01-01

    Full Text Available More and more countries worldwide implement new rules and regulations to improve energy efficiency and cut CO2 and hazardous off-gas emissions. Thus electric steelmakers need technology that keeps costs low, increases productivity and helps them adhere to environmental regulations. Decades of knowledge in preheating technology, and several different innovative applications which had been solution for many unique cases have been brought together and announced in 2010. EAF Quantum was designed as a pragmatic solution that meets requirements for high energy and cost efficiency, increased productivity and lowest emissions. Whether scrap, partly hot metal or direct-reduced iron (DRI is charged, EAF Quantum is the solution for highly productive electric steelmaking at extra low conversion costs.

  7. Primordial black hole production during preheating in a chaotic inflationary model

    CERN Document Server

    Torres-Lomas, E

    2013-01-01

    In this paper we review the production of primordial black holes (PBHs) during preheating after a chaotic inflationary model. All relevant equations of motion are solved numerically in a modified version of HLattice, and we then calculate the mass variance to determine structure formation during preheating. It is found that production of PBHs can be a generic result of the model, even though the results seem to be sensitive to the values of the smoothing scale. We consider a constraint for overproduction of PBHs that could uncover some stress between inflation-preheating models and observations.

  8. Influence of combustion-preheating vitiation on operability of a hypersonic inlet

    Science.gov (United States)

    Liu, K.; Zhu, Y.; Gao, W.; Yang, J.; Jin, Y.; Wu, Y.

    2016-11-01

    Vitiation of the test flow with combustion products is inherent in combustion wind tunnels, and its effect on experimental results needs to be clarified. In this study, the influence of air vitiation on the startability and performance of a hypersonic inlet is investigated through two-dimensional (2D) numerical simulation. The study examines the vitiation effects introduced by carbon dioxide and water vapor, on the basis of maintaining the static pressure, static temperature and Mach number of the incoming flow. The starting Mach number limits of the inlet are estimated, and it is found that both of these vitiation components lower the starting limit of the inlet. This suggests that the experimental results acquired by tests in combustion wind tunnels overestimate the startability of an inlet and, therefore, combustion-preheated facilities may not be completely trusted in this respect. Deviations in the inlet performance caused by the vitiation are also detected. These are nevertheless minor as long as the flow is at the same started or unstarted condition. A further analysis reveals that it is mainly the increase in the heat capacity, and the resulting weaker shock/compression waves and shock-wave/boundary-layer interactions that account for the aforementioned effects.

  9. Preheating after multifield inflation with nonminimal couplings, II: Resonance Structure

    CERN Document Server

    DeCross, Matthew P; Prabhu, Anirudh; Prescod-Weinstein, Chanda; Sfakianakis, Evangelos I

    2016-01-01

    This is the second in a series of papers on preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. In this paper, we work in the rigid-spacetime approximation and consider field trajectories within the single-field attractor, which is a generic feature of these models. We construct the Floquet charts to find regions of parameter space in which particle production is efficient for both the adiabatic and isocurvature modes, and analyze the resonance structure using analytic and semi-analytic techniques. Particle production in the adiabatic direction is characterized by the existence of an asymptotic scaling solution at large values of the nonminimal couplings, $\\xi_I \\gg 1$, in which the dominant instability band arises in the long-wavelength limit, for comoving wavenumbers $k \\rightarrow 0$. However, the large-$\\xi_I$ regime is not reached until $\\xi_I \\geq {\\cal O} (100)$. In the intermediate regime, with $\\xi_I \\sim {\\cal O}(10)$, the resonance structure depend...

  10. Stellar and HI Mass Functions Predicted by a Simple Preheating Galaxy Formation Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the new preheating mechanism of galaxy formation suggested by Mo et al., we construct a simple model of formation of disk galaxies within the current paradigm of galaxy formation. It incorporates preheating, gas cooling, bulge formation and star formation. The predicted stellar and HI mass functions of galaxies are discussed and compared with the observations. It is found that our model can roughly match both the observed galaxy luminosity function and the observed HI-mass function.

  11. Combustion and Vibration Analysis of Idi- Diesel Engine Fuelled With Neat Preheated Jatropha Methyl Ester

    Directory of Open Access Journals (Sweden)

    Y.Ashok Kumar Reddy

    2014-03-01

    Full Text Available Experimentation is conducted on an IDI diesel engine and the results of combustion and vibration on IDI -Diesel engine fueled with the preheated Jatropha Methyl Ester (JME are presented. The Present research trend is to replace conventional diesel by renewable alternative fuels in view of fast depletion of petroleum reserves and to reduce the exhaust emissions from the engines without altering the basic design of the engine. Due to moderately higher viscosity effects, the direct use of biodiesel in C.I. engines is limited to 20% and the limitation is based on the NO emission also. In this work, the biodiesel is preheated using on line electronically controlled electrical preheating system before it enters into the injector. Experiments are conducted on a four stroke single cylinder IDI engine to find combustion and vibration characteristics of the engine with the preheated Jatropha Methyl Ester (JME heated to temperatures viz. 60,70,80,90 and 1000C. Normally thin oils due to heating may trigger fast burning leading to either detonation or knocking of the engine. This can be predicted by recording vibration on the cylinder head in different directions. The cylinder vibrations in the form of FFT and time waves have been analyzed to estimate the combustion propensity. Experiments are done using diesel, biodiesel and biodiesel at different preheated temperatures and for different engine loading conditions keeping the speed constant at 1500 rpm. Biodiesel preheated to 600C proved encouraging in all respects.

  12. Cosmological Simulations of the Preheating Scenario for Galaxy Cluster Formation: Comparison to Analytic Models and Observations

    CERN Document Server

    Younger, Joshua D

    2007-01-01

    We perform a set of non--radiative cosmological simulations of a preheated intracluster medium in which the entropy of the gas was uniformly boosted at high redshift. The results of these simulations are used first to test the current analytic techniques of preheating via entropy input in the smooth accretion limit. When the unmodified profile is taken directly from simulations, we find that this model is in excellent agreement with the results of our simulations. This suggests that preheated efficiently smoothes the accreted gas, and therefore a shift in the unmodified profile is a good approximation even with a realistic accretion history. When we examine the simulation results in detail, we do not find strong evidence for entropy amplification, at least for the high-redshift preheating model adopted here. In the second section of the paper, we compare the results of the preheating simulations to recent observations. We show -- in agreement with previous work -- that for a reasonable amount of preheating, a...

  13. Microwave pre-heating of natural rubber using a rectangular wave guide (MODE: TE10

    Directory of Open Access Journals (Sweden)

    Doo-ngam, N.

    2007-11-01

    Full Text Available This paper presents an application of microwave radiation for pre-heating of natural rubbercompounding with various sulphur contents. The natural rubber-compounding was pre-heated by microwave radiation using a rectangular wave guide system (MODE: TE10 operating at frequency of 2.45 GHz in which the power can vary from 0 to 1500 W. In the present work, the influence of power input, sample thickness, and sulphur content were examined after applying microwave radiation to the rubber samples. Results are discussed regarding the thermal properties, 3-D network, dielectric properties and chemical structures. From the result, firstly, it was found that microwave radiation can be applied to pre-heating natural rubber-compounding before the vulcanization process. Secondly, microwave radiation was very useful for pre-heating natural rubber-compounding that has a thickness greater than 5mm. Thirdly, crosslinking in natural rubber-compounding may occurs after pre-heating by microwave radiation though Fourier Transform Infrared Spectroscopy(FTIR. Finally, there a little effect of sulphur content on temperature profiles after applying microwave radiation to the natural rubber-compounding. Moreover, natural rubber-compounding without carbon black showed a lower heat absorption compared with natural rubbercompounding filled carbon black. This is due to the difference in dielectric loss factor. This preliminary result will be useful information in terms of microwave radiation for pre-heating natural rubber-compounding and rubber processing in industry.

  14. A comparison of winter pre-heating requirements for natural displacement and natural mixing ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Andrew W. [BP Institute, University of Cambridge, Cambridge, CB3 OEZ (United Kingdom); Fitzgerald, Shaun; Livermore, Stephen [E-Stack Ltd., St Johns Innovation Centre, Cambridge (United Kingdom)

    2009-12-15

    In winter, natural ventilation can be achieved either through mixing ventilation or upward displacement ventilation (P.F. Linden, The fluid mechanics of natural ventilation, Annual Review of Fluid Mechanics 31 (1999) pp. 201-238). We show there is a significant energy saving possible by using mixing ventilation, in the case that the internal heat gains are significant, and illustrate these savings using an idealized model, which predicts that with internal heat gains of order 0.1 kW per person, mixing ventilation uses of a fraction of order 0.2-0.4 of the heat load of displacement ventilation assuming a well-insulated building. We then describe a strategy for such mixing natural ventilation in an atrium style building in which the rooms surrounding the atrium are able to vent directly to the exterior and also through the atrium to the exterior. The results are motivated by the desire to reduce the energy burden in large public buildings such as hospitals, schools or office buildings centred on atria. We illustrate a strategy for the natural mixing ventilation in order that the rooms surrounding the atrium receive both pre-heated but also sufficiently fresh air, while the central atrium zone remains warm. We test the principles with some laboratory experiments in which a model air chamber is ventilated using both mixing and displacement ventilation, and compare the energy loads in each case. We conclude with a discussion of the potential applications of the approach within the context of open plan atria type office buildings. (author)

  15. Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

    Directory of Open Access Journals (Sweden)

    Matthias Richard Kramer

    2016-01-01

    Full Text Available To test the impact of preheating (25, 37, 54, or 68 °C of TetricEvoCeram (TEC, FiltekSupremeXT (FSXT, and Venus (V on flexural strength (FS, shear bond strength (SBS and interfacial tension (IFT. FS was tested with TEC and FSXT. For SBS, glass-ceramic and human dentin substrate were fabricated and luted with the preheated resin composite (RC. SBSs of 1500 thermal cycled specimens were measured. For IFT, glass slides covered with the non-polymerized RC were prepared and contact angles were measured. Data were analyzed using 2/1-way ANOVA with Scheffé-test, and t-test (p < 0.05. Preheated TEC (37–68 °C showed higher FS compared to the control-group (25 °C (p < 0.001. FSXT presented higher FS than TEC (p < 0.001. For SBS to dentin higher values for FSXT than TEC were found. The preheating temperature showed no impact on SBS to dentin. SBS to glass-ceramic revealed a positive influence of temperature for TEC 25–68 °C (p = 0.015. TEC showed higher values than V and FSXT (p < 0.001. IFT values increased with the preheating temperature. A significant difference could be observed in every RC group between 25 and 68 °C (p < 0.001.

  16. Effect of pre-heating on the viscosity and microhardness of a resin composite.

    LENUS (Irish Health Repository)

    Lucey, S

    2010-04-01

    The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n = 15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0.001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n = 15) was 68.6 (2.3) for the top surface and 68.7 (1.8) for the bottom surface measured at 24 h post curing (specimen thickness = 1.5 mm). The corresponding values for the room temperature group were 60.6 (1.4) and 59.0 (3.5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0.001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

  17. Effect of preheating on the viscoelastic properties of dental composite under different deformation conditions.

    Science.gov (United States)

    Ahn, Kyung Hyun; Lim, Sanghyuk; Kum, Kee Yeon; Chang, Seok Woo

    2015-01-01

    Preheating of dental composites improves their flowability, facilitating successful restorations. However, the flowability of dental composites is affected not only by temperature but also by the deformation conditions. In the present work, the effects of various deformation conditions upon the viscoelastic properties of a preheated dental composite were studied. The rheological properties of Z350 dental composites at 25, 45, and 60°C were measured by a strain-controlled rheometer. When a low strain (0.03%) was applied, the preheated composite exhibited greater shear storage modulus (G') and complex viscosity (η*) than a room-temperature composite. Oppositely, when a high strain (50%) was applied, G' and η* of a preheated composite were lower than those of a room-temperature composite. Preheating of dental composites might be helpful in clinical practice both to increase the slumping resistance when minimal manipulation is used (e.g., during the build-up of a missing cusp tip) and to increase flowability when manipulation entailing high shear strain is applied (e.g., when uncured composite resin is spread on a dentin surface).

  18. Numerical Simulation of Jet Behavior and Impingement Characteristics of Preheating Shrouded Supersonic Jets

    Institute of Scientific and Technical Information of China (English)

    Guang-sheng WEI; Rong ZHU; Ting CHENG; Fei ZHAO

    2016-01-01

    As a novel supersonic j et technology,preheating shrouded supersonic j et was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and im-pingement characteristics of preheating shrouded supersonic j ets.Computational fluid dynamics (CFD)models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic j et.The preheating shrouded supersonic j et behavior was simulated and meas-ured by numerical simulation and j et measurement experiment respectively.The influence of preheating shrouded su-personic j et on gas j et penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments.The results show that the uptrend of the potential core length of shrouded super-sonic j et would be accelerated with increasing the main and shrouding gas temperatures.Also,preheating supersonic j ets demonstrated significant advantages in penetrating and stirring the liquid bath.

  19. SRC-II slurry preheater technical uncertainties. Report for the technical data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    1984-06-01

    This report reviews the performance, and draws conclusions therefrom, the coal slurry preheaters of the Ft. Lewis, Washington, Solvent Refined Coal (SRC) Pilot Plant in the following areas: Coking, Erosion Corrosion, Heat transfer and pressure drop effects. Using prudent engineering judgement it postulates how such conclusions should affect the design and operability of large preheaters in future commercial scale plants. Also a recommendation is made for a small scale research and development effort that should result in a much firmer preheater design for any future facility. This report should be read in conjunction with the Solvent Refined Coal (SRC) Final Report, and volumes 1 and 2 of Slurry Preheater Design, SRC-II Process and also Ft. Lewis Slurry Preheater Data Analysis, 1-1/2 Inch Coil by Gulf Science and Technology Company of Pittsburgh, Pennsylvania. The Pittsburg and Midway Coal Mining Co.'s background is based primarily on a racetrack shaped up-flow coil and these comments pertain specifically to a commercial heater of that type of design. 5 references, 12 figures, 1 table.

  20. Effect of pre-heating on the mechanical properties of silorane-based and methacrylate-based composites

    Science.gov (United States)

    Mohammadi, Narmin; Jafari-Navimipour, Elmira; Kimyai, Soodabeh; Ajami, Amir-Ahmad; Bahari, Mahmoud; Ansarin, Mohammad

    2016-01-01

    Background The use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. Material and Methods A Silorane-based (Silorane) and a Methacrylate-based (Z250) composite were preheated to different temperatures (25, 37, and 68 °C) and afterwards were tested with the appropriate devices for each testing protocol. The material’s flexural strength, elastic modulus, and Vickers microhardness were evaluated. Two-way ANOVA, and Tukey’s post hoc were used to analyze the data. Results Microhardness and elastic modulus increased with preheating, while flexural strength values did not increase significantly with preheating. Furthermore the methacrylate-based composite (Z250) showed higher values compared to the Silorane-based composite (Silorane) in all the tested properties. Conclusions Preheating Silorane enhances the composite’s microhardness and elastic modulus but does not affect its flexural strength. On the other hand, preheating Z250 increases its microhardness but does not change its flexural strength or elastic modulus. In addition, the Z250 composite shows higher microhardness and flexural strength than Silorane, but the elastic modulus values with preheating are similar. Therefore Z250 seems to have better mechanical properties making it the better choice in a clinical situation. Key words:Composite, elastic modulus, flexural strength, microhardness, preheating. PMID:27703604

  1. Performance Evaluation of Diesel Engine with Preheated Bio Diesel with Additives

    Science.gov (United States)

    Ram Vajja, Sai; Murali, R. B. V.

    2016-09-01

    This paper mainly reviews about the usage of preheated bio diesel added with 0.5% Etchant as an alternative fuel and evaluates its performance for various blends with different loads. Bio diesel is added with Etchant for rapid combustion as for the bio diesel, the cetane number is high that results in shorter delay of ignition and the mixture is preheated to raise its temperature to improve the combustion process. Analysis of the parameters required to define the combustion characteristics such as IP, BP, ηbth, ηm, ISFC, BSFC, IMEP, MFC, Exhaust Gas Temperature, Heat Release and heat balance is necessary as these values are significant to assess the performance of engine and its emissions of preheated bio diesel.

  2. Diagnosing laser-preheated magnetized plasmas relevant to magnetized liner inertial fusion

    Science.gov (United States)

    Harvey-Thompson, A. J.; Sefkow, A. B.; Nagayama, T. N.; Wei, M. S.; Campbell, E. M.; Fiksel, G.; Chang, P.-Y.; Davies, J. R.; Barnak, D. H.; Glebov, V. Y.; Fitzsimmons, P.; Fooks, J.; Blue, B. E.

    2015-12-01

    We present a platform on the OMEGA EP Laser Facility that creates and diagnoses the conditions present during the preheat stage of the MAGnetized Liner Inertial Fusion (MagLIF) concept. Experiments were conducted using 9 kJ of 3ω (355 nm) light to heat an underdense deuterium gas (electron density: 2.5 ×1020 cm-3=0.025 of critical density) magnetized with a 10 T axial field. Results show that the deuterium plasma reached a peak electron temperature of 670 ± 140 eV, diagnosed using streaked spectroscopy of an argon dopant. The results demonstrate that plasmas relevant to the preheat stage of MagLIF can be produced at multiple laser facilities, thereby enabling more rapid progress in understanding magnetized preheat. Results are compared with magneto-radiation-hydrodynamics simulations, and plans for future experiments are described.

  3. Effects of Preheated Composite on Micro leakage-An in-vitro Study

    Science.gov (United States)

    Raj, James David; Sherlin, Herald

    2016-01-01

    Introduction Resin composites have been the pinnacle of direct esthetic restorations ever since its discovery. However, it comes with its own disadvantages. Post-operative sensitivity and marginal discoloration frequently occur due to polymerization shrinkage and micro leakage, which is the major cause of failure in resin composite restorations. Aim To evaluate the effects of preheated composite at different temperatures on microleakage. Materials and Methods A total of 60 extracted non-carious human premolars were collected and class 1 cavity (1.5x4x 3mm) was prepared in each and were randomly divided into three groups. Group 1 (n=20) was filled with microhybrid resin composite (Heraeus Charisma Smile) at room temperature. Group 2 (n=20) was filled with the same resin composite which was preheated to 50°C and Group 3 (n=20) was filled with resin composite preheated to 60°C. Teeth were subjected to a thermocycling regime (500X, 5 - 55°C), followed by a dye infiltration by immersing in basic fuschin for 24 hours. The tooth was sectioned longitudinally and the extent or absence of micro-leakage was determined by the amount of dye penetration along the resin composite-tooth interface using a confocal microscope. Results There was minor micro-leakage detected at the occlusal margin of the control tooth specimen. The sample with preheated composite restoration at 50°C showed an intact tooth-restoration interface with no micro leakage. However, the preheated composite at 60°C showed large amount of microleakage. Conclusion Under the current limitation of the study, preheated composite at 50°C showed the least micro-leakage. PMID:27504407

  4. Effect of Intermediate Agents and Preheated Composites on Repair Bond Strength of Silorane-Based Composites

    Directory of Open Access Journals (Sweden)

    Fereshteh Shafiei

    2016-05-01

    Full Text Available Objectives: Repairing composite restorations is a challenging procedure especially when two different types of composites are used. This study aimed to compare the repair strength of silorane-based composite (SC (Filtek P90 with that of preheated SC, methacrylate composite (MC(Z250, flowable MC (Filtek Supreme Plus and different adhesive/composite combinations.Materials and Methods: Eighty-four SC specimens were fabricated and randomly divided into seven groups (G. In the control group (G7, SC was bonded immediately to SC. The other specimens were water-aged for two months and were then roughened, etched and repaired with the following materials: G1 Silorane Adhesive Bond (SAB/SC;G2 Preheated SC; G3 SAB/MC; G4 Adper Single Bond (SB/MC; G5 Flowable MC/MC; G6 Preheated MC. After water storage and thermocycling, the repaired specimens were subjected to shear bond strength testing. The data were analyzed using ANOVA and Tukey’s test.Results: Preheated SC and MC, flowable MC and SAB/SC resulted in bond strength comparable to that of the control group. Preheated SC showed significantly higher bond strength when compared to SAB/MC (P=0.04 and SB/MC (P<0.001. Bond strength of SB/MC was significantly lower than that of the other groups (P<0.05, except for SAB/SC and SAB/MC.Conclusion: All repairing materials except for SB/MC resulted in bond strength values comparable to that of the control group. Repair with preheated SC yielded the highest bond strength. 

  5. Effect of pre-heating on hardness of methacrylate- and silorane-based composites

    OpenAIRE

    Catelan, Anderson; Barreto,Bruno; Lima, Adriano; Oliveira, Marcelo; Marchi, Giselle; Aguiar, Flávio

    2014-01-01

    AIM: To evaluate the effect of composite pre-heating on the microhardness of different monomer resin-based. MATERIALS AND METHOD: Circular specimens of methacrylate- and silorane-based composite resins pre-heated at 23, 39, and 55˚ C were carried out, and cured using a halogen light-curing unit at 650 mW/cm². After 24 h, the specimens were polished and Knoop hardness number (KHN) was measured using a microhardness tester with 50-g load for 15 s. The data were analyzed with ANOVA and Tukey’s t...

  6. Preheating to around 100°C under endcap blocks before welding at KHI.

    CERN Multimedia

    Loveless, D

    2000-01-01

    The 600mm thick sector blocks of the CMS endcaps are made from three layers of 200mm plates welded together. During the manufacture at KHI, the blocks are preheated to around 100°C to prevent cracks in the welds.

  7. Enhanced preheating after multi-field inflation: on the importance of being special

    Energy Technology Data Exchange (ETDEWEB)

    Battefeld, Thorsten; Eggemeier, Alexander [Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, D-37077 Goettingen (Germany); Giblin, John T. Jr., E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: a.eggemeier@stud.uni-goettingen.de, E-mail: giblinj@kenyon.edu [Department of Physics, Kenyon College, Gambier, OH 43022 (United States)

    2012-11-01

    We discuss preheating after multi-field inflation in the presence of several preheat matter fields that become light in the vicinity of (but not at) the inflatons' VEV, at distinct extra-species-points (ESP); this setup is motivated by inflationary models that include particle production during inflation, e.g. trapped inflation, grazing ESP encounters or modulated trapping, among others. While de-phasing of inflatons tends to suppress parametric resonance, we find two new effects leading to efficient preheating: particle production during the first in-fall (efficient if many preheat matter fields are present) and a subsequent (narrow) resonance phase (efficient if an ESP happens to be at one of several distinct distances from the inflatons' VEV). Particles produced during the first in-fall are comprised of many species with low occupation number, while the latter are made up of a few species with high occupation number. We provide analytic descriptions of both phases in the absence of back-reaction, which we test numerically. We further perform lattice simulations to investigate the effects of back-reaction. We find resonances to be robust and the most likely cause of inflaton decay in multi-field trapped inflation if ESP distributions are dense.

  8. Abstract of a report on reducing resistance in gas-fired preheaters

    Energy Technology Data Exchange (ETDEWEB)

    1939-04-27

    The demands of Hydro-works Scholven to increase the capacity of one of their preheaters, with consequently greater volume of circulating gases, inspired the idea to study the resistance to the flow of gases in the preheaters. The resistance varied with the square of the velocity, so that pressure differences beyond the capacity of the single-stage Schiele blowers could be easily developed. It was intended, therefore, to determine the exact course of the pressure loss in preheaters in operation at Scholven. Since this met with many practical difficulties, it was supplemented by measurements on sheet steel models built to one-tenth their actual size. The measurements on the preheaters already in service showed that the pressure loss in the heating chamber proper, that is the pressure losses applicable to heat transmission, were small compared to the total pressure loss. The greatest proportion of the heating loss occurred in the inlet and outlet ducts and passages. This indicated that particular attention must be paid to the resistance in the ducts and the distributing points. The gas distribution needed to be arranged such that energy-consuming dampers could be eliminated. Where bends could not be avoided, guide vanes could considerably reduce the pressure loss. It was suggested to use an Escher--Weiss axial blower system instead of the Schiele radial blower. Reduction of pressure losses would increase velocity of the gases in the heating flues and thus increase heat transmission in the hairpin coils.

  9. The Accretion and Cooling of Preheated Gas in Dark Matter Halos

    CERN Document Server

    Lu, Y; Lu, Yu

    2006-01-01

    (abridged) We use a one-dimensional hydrodynamical code to investigate the effects of preheating on gas accretion and cooling in cold dark matter halos. In the absence of radiative cooling, preheating reduces the amount of gas that can be accreted into a halo, and the accreted gas fraction is determined by the ratio of the initial specific entropy of the gas to the virial entropy of the halo. In the presence of radiative cooling, preheating affects the gas fraction that can cool in two different ways. For small halos with masses 10^13Msun. We suggest that this may be the reason why the stellar mass function of galaxies breaks sharply at the massive end. Such preheating also helps create the hot diffused halos within which the "radio mode" feedback of AGNs can act effectively. In the second case, we assume the intergalactic medium is warm. Here the total amount of gas that can cool in a halo scales with halo mass as ~M^2, as would be required to match the observed stellar- and HI-mass functions in the current ...

  10. Area 3, SRC-II coal slurry preheater studies report for the technical data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    This report reviews the raw data gathered from the Preheater B test runs at Ft. Lewis, and also the Preheater B results presented in the Solvent Refined Coal (SRC) Process Final Report, Volumes 1 and 2 of Slurry Preheater Design, SRC-II Process and the Ft. Lewis Slurry Preheater Data Analysis, 1 1/2 Inch Coil by Gulf Science and Technology Corporation of Pittsburgh, Pennsylvania. attempts were made to correlate several variables not previously considered with slurry viscosity and thermal conductivity. Only partial success was realized. However, in the process of attempting to correlate these variables an understanding of why some variables could not be correlated was achieved. An attempt was also made, using multiple linear regression, to correlate coal slurry viscosity and thermal conductivity with several independent variables among which were temperature, coal concentration, total solids, coal type, slurry residence time, shear rate, and unit size. The final correlations included some, but not all, of these independent variables. This report is not a stand alone document and should be considered a supplement to work already done. It should be read in conjunction with the reports referenced above.

  11. Little evidence for non-gravitational energy feedback beyond $r_{500}$ - An end to ICM preheating?

    CERN Document Server

    Iqbal, Asif; Nath, Biman B; Ettori, Stefano; Eckert, Dominique; Malik, Manzoor A

    2016-01-01

    Non-gravitational feedback affects the nature of the intra-cluster medium (ICM). X-ray cooling of the ICM and in situ energy feedback from AGN's and SNe as well as preheating of the gas at epochs preceding the formation of clusters are proposed mechanisms for such feedback. While cooling and AGN feedbacks are dominant in cluster cores, the signatures of a preheated ICM are expected to be present even at large radii. To estimate the degree of preheating, with minimum confusion from AGN feedback/cooling, we study the non-gravitational feedback energy profiles upto $r_{200}$ for a sample of 17 galaxy clusters using joint data sets of Planck SZ pressure profiles and ROSAT/PSPC gas density profiles. We show that the estimated energy feedback profile of the ICM is consistent with zero at 1$\\sigma$ beyond $\\sim r_{500}$. The canonical value of preheating energy of 1 keV/particle, needed in order to match energy entropy floors and cluster scalings, is ruled out at $4.4\\sigma$ beyond $r_{500}$. Our results take both n...

  12. System Performance Measurement Supports Design Recommendations for Solar Ventilation Preheat System (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-08-01

    Technical briefing to report the outcomes of a data monitoring effort to determine the nature of solar vent preheat system performance problems at a U.S. military installation. The analysis reports up-to-date research and findings regarding system design, helping to clarify the issue as a factor of system design, rather than a shortcoming of SVP systems.

  13. Effect of Preheating in Hybrid Friction Stir Welding of Aluminum Alloy

    Science.gov (United States)

    Yaduwanshi, D. K.; Bag, S.; Pal, S.

    2014-10-01

    The controlled energy input into the system by introducing an extra heat source to enhance the material flow along with reduction of the plunging force remains a potential area of considerate for the development of hybrid friction stir welding (FSW) process. Hence, the effect of preheating on the weld joint properties is evaluated using plasma-assisted friction stir welding (P-FSW) process for joining aluminum alloy. A comparative study of mechanical and macro-microstructural characterizations of weld joint by FSW and P-FSW has been performed. Transverse tensile strength of weld joint is approximately 95% of base metal produced by P-FSW and is 8% more than conventional FSW welds. The effect of preheating enhances material flow and dissolution of fine oxide particles by plasma arc results in increase of strength and marginal modification of deformation behavior. The preheating brings uniformly distributed hardness in weld zone and the magnitude is higher in the advancing side with overall increase in average hardness value. Grain sizes are much finer due to the pinning effect of Al2O3 particles that retarded grain growth following recrystallization during P-FSW and thus led to more pronounced reduction in grain size and relatively brittle fracture during tensile loading of welded joint. Overall, the influence of preheating acts quite homogeneously throughout the structure as compared to conventional FSW. However, the results reveal that the development of P-FSW is still in initial stage and needs to improve in various aspects.

  14. Pre-heating Fuel for Charge Homogeneity to Improve Combustion

    Directory of Open Access Journals (Sweden)

    Arjun Shanmukam

    2013-06-01

    Full Text Available The idea of the automobile engine that people have is of one that is bygone. The automobile engine today is the pinnacle of engineering expertise, implementing the best of technologies and undergoing the best of manufacturing processes to make the closest possible achievement to perfection, from design to combustion. The art of perfection though starts much before the process itself. In case of the automobile engine, the process is the 4-Stroke cycle that most engines go through and the art we are referring to is attaining homogeneity in charge. Homogeneous charge in an Internal Combustion Engine refers to the complete mixture of fuel (Petrol and air, entering the cylinder. Ideally this would mean the complete dispersion of the atomised fuel in air. This as a result reduces the overall efficiency of the engine. To help achieve the required atomisation, reducing the Surface Tension of the fuel is a potential solution. On reduction of Surface Tension the atomisation is enhanced, possibly reaching the ideal value. This can be achieved by heating the fuel to an operating temperature for which heat can be extracted from a potential source, namely the Exhaust Manifold.

  15. Preheating System of Auxiliary Converter for Plateau Type HXD1C Locomotive%高原型HXD1C机车辅助变流器预加热系统

    Institute of Scientific and Technical Information of China (English)

    吴建雄; 陈湘; 钱勇亮

    2012-01-01

    阐述了高原型HXD1C机车辅助变流器预加热系统及逻辑控制过程,分析了选择加热电阻的方法、设计加热风道的方法以及安装传感器的方法,可为进一步确保辅助变流器在极低温环境下正常稳定运行提供参考。%It illustrated the preheating system of auxiliary converter for plateau type HXD1C locomotive and its logic control process.It analyzed the methods of selecting preheating resistance,designing air-channels and installing sensors,which provided important reference for ensuring that the auxiliary converter could run normally and steadily under the extreme cold condition.

  16. Experimental investigations of the laser cladding of protective coatings on preheated base material

    Science.gov (United States)

    Jendrzejewski, Rafal; Sliwinski, Gerard; Conde, Ana; Navas, Carmen; de Damborenea, Juan J.

    2004-06-01

    The laser cladding technique was applied to obtain Co-based stellite SF6 coatings on the chromium steel base. The coatings were prepared by means of a direct cladding of metal powder using a 1.2 kW cw CO2 laser stand with a controlled preheating of the substrate material. Results of the metallographic tests revealed a fine-grained, dendritic microstructure and proper metallic bonding between substrate and coating. A nearly constant concentration of mian elements at different areas of the coating cross-section indicated on homogeneous chemical composition of the laser-cladded SF6 alloy samples. A significant decrease of the micro-crack number with increasing temperature of the base preheating was observed. This was accompanied by a drop of the wear and corrosion resistance.

  17. Preheating after multifield inflation with nonminimal couplings, III: Dynamical spacetime results

    CERN Document Server

    DeCross, Matthew P; Prabhu, Anirudh; Prescod-Weinstein, Chanda; Sfakianakis, Evangelos I

    2016-01-01

    This paper concludes our semi-analytic study of preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. Using the covariant framework of Ref. [1], we extend the rigid-spacetime results of Ref. [2] by considering both the expansion of the universe during preheating, as well as the effect of the coupled metric perturbations on particle production. The adiabatic and isocurvature perturbations are governed by different effective masses that scale differently with the nonminimal couplings and evolve differently in time. The effective mass for the adiabatic modes is dominated by contributions from the coupled metric perturbations immediately after inflation. The metric perturbations contribute an oscillating tachyonic term that enhances an early period of significant particle production for the adiabatic modes, which ceases on a time-scale governed by the nonminimal couplings $\\xi_I$. The effective mass of the isocurvature perturbations, on the other hand, is dominated...

  18. Heating of Intracluster Gas by Jet Activities of AGN Is the "Preheating" Scenario Realistic?

    CERN Document Server

    Yamada, M; Yamada, Masako; Fujita, Yutaka

    2001-01-01

    We investigate the non-gravitational heating of hot gas in clusters of galaxies (intracluster medium; ICM) on the assumption that the gas is heated well before cluster formation ('preheating'). We examine the jet activities of radio galaxies as the sources of excess energy in ICM, and the deformation of the cosmic microwave background (the Sunyaev-Zel'dovich effect) by hot electrons produced at the jet terminal shocks. We show that the observed excess entropy of ICM and {\\sl COBE/FIRAS} upper limit for the Compton $y$-parameter are compatible with each other only when the heating by the jets occurred at relatively small redshift ($z\\lesssim 3$). Since this result contradicts the assumption of 'preheating', it suggests that the heating occurred simultaneously with or after cluster formation.

  19. Specific Angular Momentum Distribution of Disc Galaxies Formed in Preheated Intergalactic Media

    Institute of Scientific and Technical Information of China (English)

    LUO Zhi-Jian; FU Li-Ping; SHU Cheng-Gang

    2004-01-01

    Assuming that baryons within a galactic halo have the same specific angular momentum as the dark matter where they locate initially and a disc forms due to the gas cooling and condensation with the conservation of angular momentum, we investigate the angular momentum distribution in a resulting galactic disc under the new preheated galaxy formation model suggested by Mo and Mao (Mon. Not. R. Astron. Soc. 333 (2002) 768).Compared with the observational results, it can be concluded that the preheated galaxy formation model can match current observations. This model can be a good approach to solve the problems of both the angular momentum catastrophe and the mismatch of angular-momentum profiles in current disc galaxy formation models.

  20. Gravitational Waves from Abelian Gauge Fields and Cosmic Strings at Preheating

    CERN Document Server

    Dufaux, Jean-Francois; Garcia-Bellido, Juan

    2010-01-01

    Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space, and show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearence of new peaks at characteristic frequencies that are related to...

  1. The Cluster Gas Mass - Temperature Relation Evidence for a High Level of Preheating

    CERN Document Server

    McCarthy, I G; Balogh, M L; Carthy, Ian G. Mc; Babul, Arif; Balogh, Michael L.

    2002-01-01

    Recent X-ray observations have been used to demonstrate that the cluster gas mass - temperature relation is steeper than theoretical self-similar predictions drawn from numerical simulations that consider the evolution of the cluster gas through the effects of gravity and shock heating alone. One possible explanation for this is that the gas mass fraction is not constant across clusters of different temperature, as usually assumed. Observationally, however, there is no compelling evidence for gas mass fraction variation, especially in the case of hot clusters. Seeking an alternative physical explanation for the observed trends, we investigate the role of preheating the intracluster medium by some arbitrary source on the cluster gas mass - temperature relation for clusters with emission-weighted mean temperatures of greater than about 3 keV. Making use of the physically-motivated, analytic model developed by Babul et al. (2002), we find that preheating does, indeed, lead to a steeper relation. This is in agree...

  2. Operation of a cyclonic preheater in the Ca-looping for CO2 capture.

    Science.gov (United States)

    Martínez, Ana; Lara, Yolanda; Lisbona, Pilar; Romeo, Luis M

    2013-10-01

    Calcium looping is an emerging technology for CO2 capture that makes use of the calcium oxide as a sorbent. One of its main issues is the significant energy consumption in the calciner, where the regeneration of the sorbent takes place. Nevertheless, as a high temperature looping technology, the surplus heat flows may be used to reduce the energy needs in this reactor. The addition of a cyclonic preheater similar to those used in the cement industry is proposed in this work. A calcium looping system was modeled and simulated to assess the advantages and disadvantages of the inclusion of a cyclonic preheater. Despite the negative effect on the maximum average capture capacity of the sorbent, a reduction on the coal and oxygen consumptions and on the extra CO2 generated in the calciner is obtained.

  3. Influence of the Previous Preheating Temperature on the Static Coefficient of Friction with Lubrication

    Directory of Open Access Journals (Sweden)

    M. Živković

    2016-12-01

    Full Text Available Experimental investigations static coefficient of friction in lubricated conditions and pre-heating of the sample pin at high temperatures is discussed in this paper. The static coefficient of friction was measured in the sliding steel copper pins per cylinder of polyvinylchloride. Pins are previously heated in a special chamber from room temperature to a temperature of 800 oC with a step of 50 °C. Tribological changes in the surface layer of the pins caused by pre-heating the pins at high temperatures and cooling systems have very significantly influenced the increase in the coefficient of static friction. The results indicate the possibility of improving the friction characteristics of metal materials based on their thermal treatment at elevated temperatures.

  4. Simulation on temperature field of TIG welding of copper without preheating

    Institute of Scientific and Technical Information of China (English)

    LEI Yu-cheng; YU Wen-xia; LI Cai-hui; CHENG Xiao-nong

    2006-01-01

    According to the conservation of energy principle and technology characteristics of tungsten inert gas(TIG), a model of non-steady three-dimensional temperature field for red copper's TIG welding with a locomotive arc was established. The temperature field of welding pool was calculated with finite element software ANSYS. Indrafted the heat enthalpy conception and the surface distribution dual-ellipsoid model, the demands of welding numerical simulation was primely satisfied. Aimed at bad weldability of red copper, the TIG welding of thick-wall red copper was studied adopting Ar+N2 without preheating. The results show that the heating effect of arc is evidently enhanced, it is viable to achieve the no preheating TIG welding of red copper. Comparing the experimental values with the calculated ones under different technological parameters, the results indicate that the model and practical course are well matched, which proves that the model is reliable and correct.

  5. Acid skim milk gels: The gelation process as affected by preheated pH

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Vliet, van T.

    2008-01-01

    The effect of preheating milk (10 min 80 [degree sign]C) at pH values from 6.20 to 6.90 on formation of acid skim milk gels was studied by dynamic oscillation measurements. Up to pH 6.65 a higher pH of heating (pHheating) resulted in a higher G'. Since below pH 4.9 the development of G'(pH)/G'(pH=4.

  6. The effect of preheating and opacity on the sorption and solubility of a composite resin.

    Science.gov (United States)

    Castro, Fabrício Luscino Alves de; Pazinatto, Flávia Bittencourt; de Lima, Érick; Cesar, Paulo Francisco; Reges, Rogério Vieira

    2016-01-01

    This study evaluated the influence of material opacity and preheating on the sorption and solubility of a composite resin material. A commercially available composite resin and an 8 × 2-mm circular metallic matrix were used to fabricate a total of 60 specimens in 6 shades, of which 3 had conventional opacity (CA2, CA3, and CA3.5) and 3 were opaque (OA2, OA3, and OA3.5). Specimens were prepared at a room temperature of 25°C or preheated to 60°C (n = 5 per shade at each temperature). The specimens were weighed 3 times: M1, dried for 24 hours at 37°C; M2, stored for 7 days in 75% ethanol at 37°C; and M3, dried for an additional 24 hours at 37°C. The weights were used to calculate the sorption and solubility of the composite resin and were analyzed using 2-way analysis of variance and Tukey tests (α = 5%). Composite resin specimens heated at 60°C yielded lower values of sorption and solubility than did specimens prepared at 25°C (P composite shades were found to be similar (P > 0.05), except for shade CA2, which presented a greater mean solubility value than OA2 (P = 0.004). Therefore, preheating was beneficial, as it lowered both the sorption and solubility of the evaluated composite resin, but opacity had little effect on these properties.

  7. Laser Pre-Heat Studies for MagLIF with Z-Beamlet

    Science.gov (United States)

    Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, T. J.; Gomez, M. R.; Harding, E.; Jennings, C.; Kimmel, M. W.; Knapp, P.; Peterson, K.; Schollmeier, M.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Slutz, S. A.; Smith, I. C.; Speas, C. S.; Vesey, R. A.; Porter, J. L.; Campbell, E. M.; Lewis, S. M.

    2015-11-01

    Magnetized Liner Inertial Confinement Fusion (MagLIF) relies on strong pre-heat of the fuel, typically hundreds of eV. Z-Beamlet delivers up to 4 kJ of laser energy to the target to achieve this goal. Over the last year, several experimental campaigns at the Pecos target area of Sandia's Z-Backlighter Facility and in the center section of the Z-Accelerator have been performed to investigate pre-heat. Primary objectives of these campaigns were the transmission through the laser entrance hole (LEH) in dependence of window thicknesses and focus parameters (including phase plate smoothing), as well as energy coupling to the gaseous fuel. The applied diagnostic suite included a wide range of time integrated and time-resolved X-ray imaging devices, spectrometers, backscatter monitors, a full-beam laser transmission calorimeter, and X-ray diodes.We present the findings of these studies, looking ahead towards a standard pre-heat platform. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Study of laser preheat in magnetic liner inertial fusion using the AMR code FLASH

    Science.gov (United States)

    Adams, Marissa; Jennings, Christopher; Slutz, Stephen; Peterson, Kyle; Gourdain, Pierre-Alexandre; University of Rochester; Sandia National Laboratories Collaboration

    2016-10-01

    Magnetic Liner Inertial Fusion (MagLIF) on the Z Pulsed Power Accelerator involves three processes: magnetization, preheat, and compression. An issue with this scheme is the development of instabilities during laser preheat, where the Z-Beamlet laser system may not deposit energy into deuterium fuel uniformly. This study explores potential mixing between liner and fuel, and inner imprinting of seeds on a beryllium liner that may generate late instability growth and shear, using the Eulerian AMR code FLASH. We further investigate potential instability implications of an additional layer of deuterium-tritium ice, as has been proposed and assess the sensitivity of MagLIF implosions to axial variations in fuel preheat; meanwhile testing the expediency of FLASH for these scenarios. FLASH was developed in part by the DOE NNSA ASC and DOE Office of Science ASCR-supported Flash Center at the University of Chicago. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin comapny, for the U.S. Department of Energy's National Nuclear Security Administration under contract No. DE-AC04-94AL85000.

  9. Inductive Preheating in Laser Beam Welding of Multimaterial Joints of 22MnB5 and AA6016

    Science.gov (United States)

    Kügler, H.; Vollertsen, F.

    Inductive preheating is well known as possibility to heat ferromagnetic materials. In brazing preheating causes an improvement of wetting quality, e.g. smaller wetting angles and longer wetting lengths. In this paper inductive preheating is used to support a laser beam hybrid joining process. Aluminum AA6016 is molten in order to wet the surface of AlSi- coated steel 22MnB5. Investigations on the influence of preheating on wetting characteristics and intermetallic phase seam formation were carried out. Strength values up to 230 MPa have been measured in tensile shear tests. Fraction zone occurs in the aluminum base material indicating uncritical thickness of the intermetallic phase seam at the interface.

  10. An Optimized Energy Management Strategy for Preheating Vehicle-Mounted Li-ion Batteries at Subzero Temperatures

    Directory of Open Access Journals (Sweden)

    Tao Zhu

    2017-02-01

    Full Text Available This paper presents an optimized energy management strategy for Li-ion power batteries used on electric vehicles (EVs at low temperatures. In low-temperature environments, EVs suffer a sharp driving range loss resulting from the energy and power capability reduction of the battery. Simultaneously, because of Li plating, battery degradation becomes an increasing concern as the temperature drops. All these factors could greatly increase the total vehicle operation cost. Prior to battery charging and vehicle operating, preheating the battery to a battery-friendly temperature is an approach to promote energy utilization and reduce total cost. Based on the proposed LiFePO4 battery model, the total vehicle operation cost under certain driving cycles is quantified in the present paper. Then, given a certain ambient temperature, a target preheating temperature is optimized under the principle of minimizing total cost. As for the preheating method, a liquid heating system is also implemented on an electric bus. Simulation results show that the preheating process becomes increasingly necessary with decreasing ambient temperature, however, the preheating demand declines as driving range grows. Vehicle tests verify that the preheating management strategy proposed in this paper is able to save on total vehicle operation costs.

  11. Heat transfer characteristics of air cross-flow for in-line arrangement of spirally corrugated tube and smooth tube bundles

    Institute of Scientific and Technical Information of China (English)

    LU Guo-dong; ZHOU Qiang-tai; TIAN Mao-cheng; CHENG Lin; YU Xiao-li

    2005-01-01

    An experimental study on heat transfer and resistance coefficients of linearly arranged smooth and spirally corrugated tube bundles in cross-flow was performed. The heat transfer and resistance coefficients are presented in this paper with transverse and longitudinal tube-pitch and tube geometries taken into account. The experiment's results can provide technical guidelines for application to horizontal air preheater with arranged in-line spirally corrugated tube bundles, especially to the air preheater for CFBCBs (Circulating Fluidized Bed Combustion Boilers).

  12. COSTEAU - preheating and cooling by means of underground collectors with water circulation - case study (Perret building at Satigny, Geneva) and generalisation; COSTEAU. Prechauffage et rafraichissement par collecteurs souterrains a eau. Etude de cas (batiment Perret a Satigny, Geneve) et generalisation

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.; Lachal, B.

    2003-07-01

    Since a couple of years, underground collectors with air circulation have been becoming increasingly popular as a simple means for preheating (at winter time) and cooling (at summer time) of outdoor air ahead of a ventilation system for well insulated buildings. This report considers underground collectors with water circulation used for similar purposes. They are connected to the ventilation system via an air/water heat exchanger. Starting from a case study - one-year detailed in-situ measurements and data analysis from an air-heated office building near Geneva, Switzerland - computerised simulations have been performed as a sensitivity analysis tool as well as to establish recommendations and sizing rules for planners, including cost considerations. In the case study it turned out that the water-circulated underground collector, which is installed right under the basement of this well insulated building, is in thermal contact with the basement. Its main function is to damp the daily temperature oscillation of the inlet ventilation air, bringing the expected thermal comfort improvement in the summer time. However, this underground collector is unable to collect seasonally stored heat from the ground. Hence, in the winter time the main preheating contribution arises from the series-connected heat-recovery unit from the exit air. Numerical simulations show that optimal sizing of underground collectors is essential, and that both the underground collector and the well insulated building as a physical system with thermal inertia have to be simultaneously considered in the optimization process. Optimization also has to include parasitic energy (electricity) needed by fans and pumps. As outdoor air inlet can never be flooded in the case of underground collectors with water circulation the sanitary risk encountered with air-circulated underground collectors does not exist for them. Initial investment cost for water-circulated underground collectors is higher than for a

  13. Experimental research on bitumen preheating (fluidization) by using solar energy in passive mode

    Energy Technology Data Exchange (ETDEWEB)

    Luminosu, Ioan [Department of Physics, ' Politehnica' University Timisoara, 1, Regina Maria Plaza, RO 300004, Timisoara (Romania); Fara, Laurentiu [Department of Physics, ' ' Politehnica' ' University Bucharest, 313, Splaiul Independentei Blvd, RO 060032, Bucuresti (Romania)

    2009-01-15

    An important aim of worldwide research engineering is to identify new industries to introduce solar energy installations for average thermal level. Due to the mechanical and thermal properties of bitumen, such as the 44-49 C softening point of D80/100 type bitumen, this material can be preheated by using solar thermal installations. The Physics Department of 'Politehnica' University of Timisoara designed and studied a laboratory installation for preheating in environmental conditions an amount of 25.1 kg of bitumen up to 55 C per day. The paper developed a previous original research regarding bitumen preheating by using solar energy. The experimental installation was improved and experimental data were statistically processed. The main improvements were based on:-increasing the amount of incident solar radiation by: (a) reducing the height of the brick walls and replacing them with transparent glass plates; (b) painting the inner faces of the brick walls in white; -cutting down thermal losses by: (a) achievement of the double greenhouse effect in the transparent areas of the installation; (b) change of the brick walls into passive walls. The performances of the installation were improved as follows:-increasing time of the bitumen temperature increased from 7 hours to 8 hours, in the interval 8 am-4 pm; -bitumen maximum temperature increased from 55 to 63.3 C; -average temperature in bitumen increased from 41.4 to 46.4 C; -maximum efficiency increased from 12 to 14.4%; -daily average efficiency increased from 6.3 to 7.3%; -maximum difference between the bitumen temperature and environmental one increased from 24 to 32 C. (author)

  14. Optimal Heater Control with Technology of Fault Tolerance for Compensating Thermoforming Preheating System

    Directory of Open Access Journals (Sweden)

    Zhen-Zhe Li

    2015-01-01

    Full Text Available The adjustment of heater power is very important because the distribution of thickness strongly depends on the distribution of sheet temperature. In this paper, the steady state optimum distribution of heater power is searched by numerical optimization in order to get uniform sheet temperature. In the following step, optimal heater power distribution with a damaged heater was found out using the technology of fault tolerance, which will be used to reduce the repairing time when some heaters are damaged. The merit of this work is that the design variable was the power of each heater which can be directly used in the preheating process of thermoforming.

  15. Damage to Preheated Tungsten Targets after Multiple Plasma Impacts Simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E.; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Makhlay, V.A.; Tereshin, V.I. [Kharkov Inst. of Physics and Technology, Inst. of Plasma Physics of National Science Center, Akademicheskaya street, 1, 61108 Kharkov (Ukraine); Landman, I.; Pestchanyi, S. [FZK-Forschungszentrum Karlsruhe, Association Euratom-FZK, Technik und Umwelt, Postfach 3640, D-7602 1 Karlsruhe (Germany)

    2007-07-01

    Full text of publication follows: The energy loads onto ITER divertor surfaces associated with the Type I ELMs are expected to be up to 1 MJ/m{sup 2} during 0.1-0.5 ms, with the number of pulses about 103 per discharge. Tungsten is a candidate material for major part of the surface, but its brittleness can result in substantial macroscopic erosion after the repetitive heat loads. To minimize the brittle destruction, tungsten may be preheated above the ductile-to-brittle transition temperature. In this work the behavior of preheated tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 450 pulses of the duration 0.25 ms and the heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is respectively below and above the melting threshold. During the exposures the targets were permanently kept preheated at 650 deg. C by a heater at target backside. In the course of exposures the irradiated surfaces were examined after regular numbers of pulses using the SEM and the optical microscopy. The profilometry, XRD, microhardness and weight loss measurements have been performed, as well as comparisons of surface damages after the heat loads both below and above the melting threshold. It is obtained that macro-cracks do not develop on the preheated surface. After the impacts with surface melting, a fine mesh of intergranular microcracks has appeared. The width of fine intergranular cracks grows with pulse number, achieving 1-1.5 microns after 100 pulses, and after 210 pulses the crack width increases up to 20 microns, which is comparable with grain sizes. Threshold changes in surface morphology resulting in corrugation structures and pits on the surface as well as importance of surface tension in resulted 'micro-brush' structures are discussed. Further evolution of the surface pattern is caused by loss of separated grains on exposed

  16. Little evidence for entropy and energy excess beyond r500 - an end to ICM pre-heating?

    Science.gov (United States)

    Iqbal, Asif; Majumdar, Subhabrata; Nath, Biman B.; Ettori, Stefano; Eckert, Dominique; Malik, Manzoor A.

    2017-02-01

    Non-gravitational feedback affects the nature of the intracluster medium (ICM). X-ray cooling of the ICM and in situ energy feedback from active galactic nuclei (AGNs) and supernovae as well as pre-heating of the gas at epochs preceding the formation of clusters are proposed mechanisms for such feedback. While cooling and AGN feedbacks are dominant in cluster cores, the signatures of a pre-heated ICM are expected to be present even at large radii. To estimate the degree of pre-heating, with minimum confusion from AGN feedback/cooling, we study the excess entropy and non-gravitational energy profiles up to r200 for a sample of 17 galaxy clusters using joint data sets of Planck Sunyaev-Zel'dovich pressure and ROSAT/Position Sensitive Proportional Counter gas density profiles. The canonical value of pre-heating entropy floor of ≳300 keV cm2, needed in order to match cluster scalings, is ruled out at ≈3σ. We also show that the feedback energy of 1 keV particle-1 is ruled out at 5.2σ beyond r500. Our analysis takes both non-thermal pressure and clumping into account which can be important in outer regions. Our results based on the direct probe of the ICM in the outermost regions do not support any significant pre-heating.

  17. Developing a Pre-Heat Platform for MagLIF with Z-Beamlet

    Science.gov (United States)

    Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, T. J.; Bliss, D. E.; Glinsky, M. E.; Campbell, E. M.; Gomez, M. R.; Harding, E.; Hansen, S. B.; Jennings, C. A.; Kimmel, M. W.; Knapp, P. F.; Lewis, S. M.; McBride, R. D.; Peterson, K.; Schollmeier, M.; Scoglietti, D. J.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Rochau, G. A.; Slutz, S. A.; Smith, I. C.; Weiss, M. R.; Porter, J. L.

    2016-10-01

    Sandia's Magnetized Liner Inertial Fusion Program has put one of the main objectives towards developing standard platform for a `preconditioned' target, providing a scenario that reproducibly delivers pre-heated fuel. The majority of this effort has been done at the ``Pecos'' Target Area using Sandia's Z-Beamlet laser to provide the pre-heat energy, just like for fully integrated MagLIF experiments. The nature and magnitude of Laser-Plasma-Instabilities during this process are particularly important, since they can lead to less energy in the fuel (backscatter processes) or to energy deposition in less desirable areas (filamentation/scatter). We present results for Stimulated Brillouin Backscatter and forward scatter, and show the effect of the laser pulse shape to laser-entrance-hole transmission and blast wave propagation in the fuel. Sandia is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. DOE's Nat'l Nucl. Sec. Admin. under contract DE-AC04-94AL85000.

  18. Velocity Interferometer blanking due to preheating in a double pulse planar experiment

    Energy Technology Data Exchange (ETDEWEB)

    Laffite, S.; Combis, P.; Clerouin, J.; Recoules, V.; Rousseaux, C.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Baton, S. D.; Koenig, M. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)

    2014-08-15

    Optical diagnostics, such as VISAR (Velocity Interferometer System for Any Reflector) or SOP (Streaked Optical Pyrometry), have become essential in shock timing experiments. Their high precision allows for accurate measurements of shock velocities, chronometry, and brightness temperature. However, in some instances, these measurements can be compromised. In planar shock coalescence experiments recently performed at the LULI facility [Baton et al., Phys. Rev. Lett. 108, 195002 (2012)], VISAR signal loss was observed. In these experiments, a strong shock launched by a high-intensity spike catches up with a previously shock launched by an earlier, low-intensity beam. The disappearance of the VISAR signal is attributed to a preheating of the coronal plasma by x-rays generated by the high intensity spike. The signal does not disappear if the high-intensity spike starts after VISAR probe beam begins to reflect off of the first shock. The VISAR diagnostic, modeled using an assessment of the optical index in quartz, compares favorably to experimental results. This provides evidence that x-ray preheating can cause blanking of the VISAR signal in quartz.

  19. Direct Measurements of Hot-Electron Preheat in Inertial Confinement Fusion

    Science.gov (United States)

    Christopherson, A. R.; Betti, R.; Howard, J.; Bose, A.; Forrest, C. J.; Theobald, W.; Campbell, E. M.; Delettrez, J. A.; Stoeckl, C.; Edgell, D. H.; Seka, W.; Davis, A. K.; Michel, D. T.; Glebov, V. Yu.; Wei, M. S.

    2016-10-01

    In laser-driven inertial confinement fusion, a spherical capsule of cryogenic DT with a low- Z (CH, Be) ablator is accelerated inward on low entropy to achieve high hot-spot pressures at stagnation with minimal driver energy. Hot electrons generated from laser-plasma instabilities can compromise this performance by preheating the DT fuel, which results in early decompression of the imploding shell and lower hot-spot pressures. The hot-electron energy deposited into the DT for direct-drive implosions is routinely inferred by subtracting hard x-ray signals between a cryogenic implosion and its mass-equivalent, all-CH implosion. However, this technique does not measure the energy deposited into the unablated DT, which fundamentally determines the final degradation in hot-spot pressure. In this work, we report on experiments conducted with high- Z payloads of varying thicknesses to determine the hot-electron energy deposited into a payload that is mass equivalent to the amount of unablated DT present in typical DT layered implosions on OMEGA. These are the first measurements to directly probe the effect of preheat on performance degradation. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  20. Investigation of Thermal Conductivity and Heat Characteristics of Oil Sands Using Ultrasound Irradiation for Shortening the Preheating Time

    Science.gov (United States)

    Kamagata, Shingo; Kawamura, Youhei; Okawa, Hirokazu; Mizutani, Koichi

    2012-07-01

    Oil sands are attractive as an energy resource. Bitumen, which is found in oil sands, has high viscosity, so that it does not flow. Most oil sands are underground and are developed with a method called steam-assisted gravity drainage (SAGD). Hot steam is injected underground to fluidize bitumen and promote its recovery. However, the preheating time is too long. One way of reducing running costs is by shortening the preheating time. Previous studies have found that bitumen can be extracted from oil sands efficiently by applying ultrasonic irradiation, but SAGD was not applied directly in these cases. Thus, the purpose of this study is to apply ultrasonic irradiation to SAGD, thereby shortening the preheating time of oil sands. As a model experiment for SAGD, heat transfer experiments in a sand layer made with Toyoura sand and silicone oil were conducted and the thermal effect with ultrasound was investigated.

  1. Nonlinear ultrasonic phased array imaging of closed cracks using global preheating and local cooling

    Science.gov (United States)

    Ohara, Yoshikazu; Takahashi, Koji; Ino, Yoshihiro; Yamanaka, Kazushi

    2015-10-01

    Closed cracks are the main cause of underestimation in ultrasonic inspection, because the ultrasound transmits through the crack. Specifically, the measurement of closed-crack depth in coarse-grained materials, which are highly attenuative due to linear scatterings at the grains, is the most difficult issue. To solve this problem, we have developed a temporary crack opening method, global preheating and local cooling (GPLC), using tensile thermal stress, and a high-selectivity imaging method, load difference phased array (LDPA), based on the subtraction of phased array images between different stresses. To demonstrate our developed method, we formed a closed fatigue crack in coarse-grained stainless steel (SUS316L) specimen. As a result of applying it to the specimen, the high-selectivity imaging performance was successfully demonstrated. This will be useful in improving the measurement accuracy of closed-crack depths in coarse-grained material.

  2. Damage to preheated tungsten targets after multiple plasma impacts simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)], E-mail: garkusha@ipp.kharkov.ua; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Makhlaj, V.A. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Pestchanyi, S. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

    2009-04-30

    The behavior of a preheated at 650 deg. C tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 350 pulses of the duration 0.25 ms and the surface heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is below and above the melting threshold, respectively. The development of surface morphology of the exposed targets as well as cracking and swelling at the surface is discussed. First comparisons of obtained experimental results with corresponding numerical simulations of the code PEGASUS-3D are presented.

  3. Effect Of Preheating And Different Moisture Content Of Input Materials On Durability Of Pellets Made From Different Phytomass Content

    Directory of Open Access Journals (Sweden)

    Macák Miroslav

    2015-03-01

    Full Text Available This paper analyses the effects of the storage process on the durability of pellets made of different types of biomass (lucerne hay, maize stover, wheat straw, miscanthus, prickly lettuce for energy purposes. Pellets were produced on a hydraulic press that allowed modifying the size of pellets. The durability of pellets was measured on a special testing instrument according to the ASAE S269.4 (2007 standard method. The pellets used in the test were produced by pressing without preheating and with preheating. Durability rating was expressed as the ratio of the original mass of pellets and the mass of pellets remaining on a 17 mm opening sieve after tumbling. Storage negatively affected the durability of pellets made without preheating for all the types of biomass materials in different moisture contents. On the other hand, there was some positive response to storing of pellets made with preheating. The durability of pellets made of maize stover, wheat straw and miscanthus in the moisture content of 5 % increased with storing.

  4. Effect of Preheating on the Inertia Friction Welding of the Dissimilar Superalloys Mar-M247 and LSHR

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Semiatin, S. L.

    2016-12-01

    Differences in the elevated temperature mechanical properties of cast Mar-M247 and forged LSHR make it difficult to produce sound joints of these alloys by inertia friction welding (IFW). While extensive plastic upset occurs on the LSHR side, only a small upset is typically developed on the Mar-M247 side. The limited plastic flow of Mar-M247 thus restricts the extent of "self-cleaning" and mechanical mixing of the mating surfaces, so that defects remain at the bond line after welding. In the present work, the effect of local preheating of Mar-M247 immediately prior to IFW on the welding behavior of Mar-M247/LSHR couples was determined. An increase in the preheat temperature enhanced the plastic flow of Mar-M247 during IFW, which resulted in extensive mechanical mixing with LSHR at the weld interface, the formation of extensive flash on both the Mar-M247 and LSHR sides, and a sound bond. Performed in parallel with the experimental work, finite-element-method (FEM) simulations showed that higher temperatures are achieved within the preheated sample during IFW relative to its non-preheated counterpart, and plastic flow is thus facilitated within it. Microstructure and post-weld mechanical properties of the welded samples were also established.

  5. Effects of extrusion-billet preheating on the microstructure and properties of Zr-2.5Nb pressure tube materials

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, R.; Cann, C.D. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada). Whiteshell Labs.; Aldridge, S.A. [Nu-Tech Precision Metals, Inc., Arnprior, Ontario (Canada); Theaker, J.R.; Coleman, C.E. [Atomic Energy of Canada Ltd., Chalk River, Ontario (Canada). Chalk River Labs.

    1996-12-31

    The effects of extrusion temperature and pre-heat soak time for billets on the mechanical properties of Zr-2.5Nb pressure tubes for CANDU reactors have been examined. The {beta}-quenched billets from a quadruple-melted ingot containing approximately 1,200 ppm of oxygen were extruded at 780, 815, and 850 C with pre-heat soak times of 15 to 300 min. The extruded hollows were finished by cold drawing (with a 28% reduction in area) and then stress relieving at 400 C. The {alpha}-phase grain structure, tensile strength, and fracture toughness properties were found to vary with the pre-heat temperature and soak time. All the materials were tough because embrittling impurities were absent. The tubes with 780 C preheat had a very fine and uniform {alpha}-grain structure, giving high strength and toughness at all soak times. The opposite was true for the 850 C soaks; the grain structure was coarse and inhomogeneous and the materials tended to be less strong and less touch. The tubes with the 815 C soaks showed intermediate values of strength and toughness. These variations in mechanical properties are discussed in terms of {alpha}-grain refinement and oxygen enrichment.

  6. Shock experiments on pre-heated alpha- and beta-quartz: 1. Optical and density data

    Science.gov (United States)

    Langenhorst, Falko; Deutsch, Alexander

    1994-07-01

    Discs of single crystal quartz, unheated, and pre-heated to 275 C and 540 C (i.e., alpha-quartz) and 630 C (i.e., beta-quartz) were experimentally shocked to pressures ranging from 20 to 40 GPa, with the shock front propagating parallel to either (10-10) or (0001). Refractive indices, density and the orientation of planar deformation features (PDFs) were determined on the recovered quartz samples. Refractive indices of pre-heated quartz are unaffected up to 25 GPa but density starts to decrease slightly up to this pressure. Above 25 GPa, pre-heating causes drastic variations: Refractive indices and birefringence of quartz shocked at ambient temperature decrease continuously, until complete isotropization is reached at 35 GPa. In quartz shocked at 630 C, refractivity drops discontinuously in the interval from 25 to 26 GPa, and complete transformation to diaplectic glass is reached at 26 GPa. Density follows the trends demonstrated by the optical parameters, with higher pre-shock temperatures yielding lower density at a given shock pressure. These results indicate that the threshold pressure for the onset of transformation to diaplectic quartz glass is largely temperature-invariant, lying at 25 GPa, whereas the pressure limit for complete transformation decreases with increasing pre-shock temperature from approximately equal 35 to approximately equal 26 GPa. Quartz shocked parallel to (0001) always has a higher density and refractivity than that shocked parallel to (10-10), indicating a significant influence of the structural anisotropy. This is also evident from the distribution of PDF orientations. Pressures greater than or equal 25 GPa cause, in quartz shocked parallel to (10-10), PDFs that are predominantly oriented parallel to set of (10-12) planes, while quartz shocked to the same pressures but parallel to (0001) contains almost exclusively PDFs parallel to set of (10-13) planes. PDF orientations in quartz shocked at ambient temperature parallel to (10-10) show

  7. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  8. Distribution of Hg, As and Se in material and flue gas streams from preheater-precalciner cement kilns and vertical shaft cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Ding, Qiong; Karstensen, Kåre Helge; Engelsen, Christian J; Li, Li; Ren, Yong; Jiang, Chen

    2015-08-01

    The aim of this study was to evaluate the behavior of Hg, As, and Se in cement production. Two types of cement plants were studied, including the vertical shaft kiln (VSK) and preheater-precalciner kiln (PPK) processes. Determination of Hg, As, and Se in the main material and gas streams were performed. It was found that recycling of particulate matter captured by an air pollution control device caused a significant enrichment of Hg and As inside both processes. The total quantity of Hg entering the process and the quantity emitted to the atmosphere were found to be 10-109 and 6.3-38 mg, respectively, per ton of clinker produced. The average Hg emission was calculated to be around 41% of the total mercury input. The emissions found complied with the European Union (EU) limit and exceeded partly the U.S. limit. Furthermore, it was found that oxidized mercury was the dominant species in the PPK process, whereas the reduced form was dominant in the VSK process, due to the oxidizing and reducing gas conditions, respectively. Regarding the distribution of As and Se, the major amounts were bound to the solid materials, that is, cement clinker and particulate matter. Based on cement production data in China in 2013, the annual emissions of Hg and As were estimated to be in the range of 8.6-52 and 4.1-9.5 tons, respectively.

  9. Effects of Preheating Temperature,Moisture and Sodium Metabisulfite Content on Property of Maize Flour Dough

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Processing temperature,maze flour particle size,and level of water and sodium metabisulfite were varied during the preparation of maize noodles.Preheated to 90-95 ℃ a mixture of maize flour or meal,water(43%-45% moisture) and salt enabled the preparation of noodles using a pasta extruder.Maize flour with smaller particle size yielded better noodles than did maize meal.The addition of sodium metabisulfite enabled the production of noodles at lower processing temperatures; however,cooking losses increased.Processing maize flour with higher water absorption yielded noodles that required longer cooking time but with decreased losses.The functionalities of starch and protein in raw ingredients and in products were determined.Starch gelatinized and retorgraded during processing maize noodles,as indicated by changes in pasting viscosity curves.Maize proteins contributed to the increased viscosity of dough above 40 ℃.The increased integrity of cooked maize noodles,however,corresponded to the increased amounts of gelatinized and retrograded starch.

  10. Application of a Device for Uniform Web Drying and Preheating Using Microwave Energy

    Energy Technology Data Exchange (ETDEWEB)

    Frederick W. Ahrens; C. Habeger; J. Loughran; T. Patterson

    2003-10-02

    The project summarized in this report dealt with an evaluation of new microwave applicator ideas for paper preheating and drying. The technical basis for success in this project is the fact that Industrial Microwave Systems has recently identified certain previously unrecognized wave guide ''design variables'' and hardware implementation concepts that can be employed to greatly improve the uniformity of microwave energy distribution for continuous flow processes. Two applicator concepts were ultimately evaluated, a Cross-Machine Direction (CD) oriented applicator and a Machine Direction (MD) oriented applicator. The economic basis for success is the result of several factors. Since 1985, the capital expenditure required for an industrial microwave applicator system has decreased by a factor of four. The maintenance costs have decreased by a factor of 10 and the life expectancy of the magnetron has increased by more than a factor of four to in excess of 8,000 hours (nearly one year at 24 hours/day operation).

  11. MINLP model for simultaneous scheduling and retrofit of refinery preheat train

    Directory of Open Access Journals (Sweden)

    Zulkafli N. Izyan, M. Noryani, Abdul H. Dayanasari, M. Shuhaimi

    2014-01-01

    Full Text Available There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient heat exchangers lead to higher fuel demand and higher carbon emission. This paper presents mixed-integer nonlinear programming (MINLP model for simultaneous cleaning and retrofit of crude preheat train (CPT in oil refinery plant. The formulation of the model is generated and coded in General Algebraic Modeling System (GAMS. The model minimizes the cost of energy and the cost of cleaning. The model takes into account the changes in fouling rates throughout time. There are two cases for this study. The cases are online cleaning (Case 1 and simultaneous online cleaning and retrofit (Case 2. The largest energy saving are found in Case 2. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT from 215oC to 227oC. Furthermore, Case 2 results in the highest percentage of cost saving by about 59%. The payback period for investment in high efficiency heat exchangers is 5 months. Thus, Case 2 is the most cost effective option for reductions of energy consumption in Crude Distillation Unit (CDU.

  12. Effect of substrate preheating temperature and coating thickness on residual stress in plasma sprayed hydroxyapatite coating

    Science.gov (United States)

    Tang, Dapei

    2015-07-01

    A thermal-mechanical coupling model was developed based on thermal-elastic- plastic theory according the special process of plasma spraying Hydroxyapatite (HA) coating upon Ti-6Al-4V substrate. On the one hand, the classical Fourier transient heat conduction equation was modified by introducing the effect item of deformation on temperature, on the other hand, the Johnson-Cook model, suitable for high temperature and high strain rate conditions, was used as constitutive equation after considering temperature softening effect, strain hardening effect and strain rate reinforcement effect. Based on the above coupling model, the residual stress field within the HA coating was simulated by using finite element method (FEM). Meanwhile, the substrate preheating temperature and coating thickness on the influence of residual stress components were calculated, respectively. The failure modes of coating were also preliminary analyzed. In addition, in order to verify the reliability of calculation, the material removal measurement technique was applied to determine the residual stress of HA coating near the interface. Some important conclusions are obtained.

  13. GMA-laser Hybrid Welding of High-strength Fine-grain Structural Steel with an Inductive Preheating

    Science.gov (United States)

    Lahdo, Rabi; Seffer, Oliver; Springer, André; Kaierle, Stefan; Overmeyer, Ludger

    The industrial useof GMA-laser hybrid welding has increased in the last 10 years, due to the brilliant quality of the laser beam radiation, and higher laser output powers. GMA-laser hybrid welding processes operate in a common molten pool. The combination of the laser beam and the arc results in improved welding speed, penetration depth, heat affected zone and gap bridgeability. Single-layer, GMA-laser hybrid welding processes have been developed for high-strength fine-grain structural steels with a grade of S690QL and a thickness of 15 mm and 20 mm. In addition, the welding process is assisted by an integrated, inductive preheating process to improve the mechanical properties of the welding seam. By using the determined parameters regarding the energy per unit length, and the preheating temperature, welding seams with high quality can be achieved.

  14. An analysis of metallurgical ladle preheating; Uma analise do processo de pre-aquecimento da panela de aciaria

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Eliana F. [Ouro Preto Univ., MG (Brazil). Escola de Minas; Figueira, Renato M. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica

    1996-12-31

    An analysis of the pre-heating effects of the siderurgical ladle refractory lining on the steel making process is developed. The modeling is based essentially on the transient two-dimensional heat conduction equation, expressed in cylindrical coordinates, and also taking into account radiation and convection boundary conditions. The solution procedure is accomplished by means of an `ANSYS` F.E.M. scheme. The analysis enables the evaluation of the preheating influence on the other phases of the complete continuous casting process . The conditions which have to be used in the control of the whole process can be determined by this simulation, enabling the optimization of energy consumption, refractory lining wear, and holding time. (author) 10 refs., 6 figs.

  15. Formation of the preheated zone ahead of a propagating flame and the mechanism underlying the deflagration-to-detonation transition

    Science.gov (United States)

    Liberman, M. A.; Kuznetsov, M.; Ivanov, A.; Matsukov, I.

    2009-01-01

    The Letter presents analytical, numerical and experimental studies of the mechanism underlying the deflagration-to-detonation transition (DDT). Insight into how, when, and where DDT occurs is obtained by analyzing analytically and by means of multidimensional numerical simulations dynamics of a flame accelerating in a tube with no-slip walls. It is shown that the deflagration-to-detonation transition exhibits three separate stages of evolution corroborating majority experimental observations. During the first stage flame accelerates and generates shocks far ahead of the flame front. During the second stage the flame slows down, shocks are formed in the immediate proximity of the flame front and the preheated zone ahead of the flame front is created. The third stage is self-restructuring of the steep temperature profile within the flame, formation of a reactivity gradient and the actual formation of the detonation wave itself. The mechanism for the detonation wave formation, given an appropriate formation of the preheated zone, seems to be universal and involves a reactivity gradient formed from the initially steep flame temperature profile in the presence of the preheated zone. The developed theory and numerical simulations are found to be well consistent with extensive experiments of the DDT in hydrogen-oxygen and ethylene-oxygen mixtures in tubes with smooth and rough walls.

  16. Performance and emission evaluation of a CI engine fueled with preheated raw rapeseed oil (RRO)-diesel blends

    Energy Technology Data Exchange (ETDEWEB)

    Hazar, Hanbey [Department of Automotive, Faculty of Technical Education, Firat University, Elazig 23119 (Turkey); Aydin, Hueseyin [Department of Automotive, Faculty of Technical Education, Batman University, Batman 72060 (Turkey)

    2010-03-15

    Many studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil-50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil-80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO's viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil. (author)

  17. Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF.

    Science.gov (United States)

    Döppner, T; Dewald, E L; Divol, L; Thomas, C A; Burns, S; Celliers, P M; Izumi, N; Kline, J L; LaCaille, G; McNaney, J M; Prasad, R R; Robey, H F; Glenzer, S H; Landen, O L

    2012-10-01

    We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.

  18. Study on heat collector of the solar system utilizing outdoor air. Experimental results in cases of cold and warm regions; Gaiki donyushiki solar system no shunetsubu ni kansuru kenkyu. Kanreichi to ondanchi ni okeru shunetsu jikken to kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Komano, S.; Ebara, Y. [OM Solar Association, Shizuoka (Japan); Wada, H. [Wada Building Constructors Co. Ltd., Hokkaido (Japan)

    1996-10-27

    An experiment on heat collection was made in the heat collector of a solar system utilizing outdoor air in cold and warm regions. In this system, outdoor air is heated by the air circulation layer on the roof exposed to solar radiation. The heated air is supplied to the object space for heating and ventilation. In the experiment in a cold region, the heat collection characteristics can be adjusted by putting a baffle plate in the air duct according to the experiment of a glass heat collector. The heat collecting air layer on only the iron roof may leak or freeze in the region subject to coldness or heavy snowfall. Therefore, preheat forms the space of a garret, and the preheat temperature comparatively becomes low. The data in which the heat collection characteristics can be adjusted using only a glass heat collector is required corresponding to the regional situation. In the experiment in a warm region, an experiment was made inclusive of the preheat for which outdoor air is absorbed at the eaves. As a result, the heat collection characteristics of preheat were improved. Moreover, a heat collection temperature of about 60{degree}C was obtained on the heat collection surface including the preheat. 1 ref., 12 figs., 3 tabs.

  19. Effect of preheating of low shrinking resin composite on intrapulpal temperature and microtensile bond strength to dent

    Directory of Open Access Journals (Sweden)

    Heba A. El-Deeb

    2015-05-01

    Full Text Available The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT and dentin microtensile bond strength (μTBS was evaluated. For the IPT, teeth (n = 15 were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth. The discs were divided into three groups (n = 10/group according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24 were obtained. P90 System Adhesive was applied according to manufacturer’s instructions then Filtek LS was placed at the tested temperatures (n = 6. Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm2. The sticks (24/group were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM. For both preheated groups, IPT increased equally by 1.5–2 °C upon application of the composite. After light curing, IPT increased by 4–5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS.

  20. Effect of preheating of low shrinking resin composite on intrapulpal temperature and microtensile bond strength to dentin.

    Science.gov (United States)

    El-Deeb, Heba A; Abd El-Aziz, Sara; Mobarak, Enas H

    2015-05-01

    The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT) and dentin microtensile bond strength (μTBS) was evaluated. For the IPT, teeth (n = 15) were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth). The discs were divided into three groups (n = 10/group) according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C) or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP) and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24) were obtained. P90 System Adhesive was applied according to manufacturer's instructions then Filtek LS was placed at the tested temperatures (n = 6). Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm(2)). The sticks (24/group) were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM). For both preheated groups, IPT increased equally by 1.5-2 °C upon application of the composite. After light curing, IPT increased by 4-5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS.

  1. Destruction of DDT wastes in two preheater/precalciner cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Karstensen, Kåre Helge; Ding, Qiong; Wang, Kaixiang; Wang, Zuguang

    2014-04-01

    The destruction of DDT formulations and DDT contaminated soil was conducted by feeding wastes into the flue gas chamber at the kiln inlet of two different preheater/precalciner cement kilns in China. The concentration of DDT, PCDD/PCDFs and HCB were measured in the flue gas of the main stack, in the solid material under baseline conditions and when feeding DDT-wastes. The destruction efficiency and the destruction and removal efficiency for DDT were in the range of 99.9335%-99.9998% and 99.9984%-99.9999%, respectively. The emissions of PCDD/PCDFs and HCB in the flue gas varied in the range of 0.0019-0.0171 ng I-TEQ/Nm(3) and 0.0064-0.0404 μg/Nm(3), respectively. The emission factor for PCDD/PCDF and HCB varied from 0.0137 to 0.0281 μg/ton and from 17.32 to 109.34 μg/ton of clinker, respectively. The concentration of PCDD/PCDFs and HCB in solid samples decreased as follows: cement kiln dust, 4.1-5 ng I-TEQ/kg and 0.70-0.71 μg/kg, respectively; >raw meal, 0.82-0.97 ng I-TEQ/kg and 0.18 μg/kg, respectively; >cement clinker, 0.09-0.22 ng I-TEQ/kg and 0.14-0.18 μg/kg, respectively. This study indicates that the feeding of DDT and POPs-wastes to the lower temperature part of a cement kiln system possibly to create a buildup of trace not-destroyed compounds in the system and might cause emissions; the technical feasibility and the environmental acceptability of this practice need to be investigated thoroughly.

  2. Equation of state of Mo from shock compression experiments on preheated samples

    Science.gov (United States)

    Fat'yanov, O. V.; Asimow, P. D.

    2017-03-01

    We present a reanalysis of reported Hugoniot data for Mo, including both experiments shocked from ambient temperature (T) and those preheated to 1673 K, using the most general methods of least-squares fitting to constrain the Grüneisen model. This updated Mie-Grüneisen equation of state (EOS) is used to construct a family of maximum likelihood Hugoniots of Mo from initial temperatures of 298 to 2350 K and a parameterization valid over this range. We adopted a single linear function at each initial temperature over the entire range of particle velocities considered. Total uncertainties of all the EOS parameters and correlation coefficients for these uncertainties are given. The improved predictive capabilities of our EOS for Mo are confirmed by (1) better agreement between calculated bulk sound speeds and published measurements along the principal Hugoniot, (2) good agreement between our Grüneisen data and three reported high-pressure γ ( V ) functions obtained from shock-compression of porous samples, and (3) very good agreement between our 1 bar Grüneisen values and γ ( T ) at ambient pressure recalculated from reported experimental data on the adiabatic bulk modulus K s ( T ) . Our analysis shows that an EOS constructed from shock compression data allows a much more accurate prediction of γ ( T ) values at 1 bar than those based on static compression measurements or first-principles calculations. Published calibrations of the Mie-Grüneisen EOS for Mo using static compression measurements only do not reproduce even low-pressure asymptotic values of γ ( T ) at 1 bar, where the most accurate experimental data are available.

  3. Recycling ash into the first stage of cyclone pre-heater of cement kiln.

    Science.gov (United States)

    Zhan, Ming-Xiu; Fu, Jian-Ying; Havukainen, Jouni; Chen, Tong; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-10-01

    Fly ash collected from the bag filter could be recycled into the first stage of the cyclone pre-heater of the cement kiln, resulting in the possible enrichment of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, soxhlet fly ash (SFA) and raw meal (RM) were selected as the basis for the PCDD/F formation experiments. The levels of 2,3,7,8-PCDD/Fs formed on the SFA and RM were observed to be 2550pg/g (157pg I-TEQ/g) and 1142pg/g (55pg I-TEQ/g), respectively. While less 2,3,7,8-PCDD/Fs was detected when SFA was mixed with RM, suggesting that recycling cement kiln ash would not largely increase the concentration of PCDD/Fs in flue gas. Furthermore, the possible influencing factors on the PCDD/F formation were also investigated. The formation of 2,3,7,8-PCDD/Fs was up to 10,871pg/g (380pg I-TEQ/g) with the adding of CuCl2, which was much higher than the results of CuO and activated carbon. Most importantly, the homologue, congener and gas/particle distribution of PCDD/Fs indicated that de novo synthesis was the dominant PCDD/F formation pathway for SFA. Lastly, principal component analysis (PCA) was also conducted to identify the relationship between the compositions of reactant and the properties of PCDD/Fs produced.

  4. Effect of Pre-heating on Microtensile Bond Strength of Composite Resin to Dentin.

    Directory of Open Access Journals (Sweden)

    Abdolrahim Davari

    2014-10-01

    Full Text Available Direct composite resin restorations are widely used and the impact of different storage temperatures on composites is not well understood. The purpose of this study was to evaluate the microtensile bond strength of composite to dentin after different pre-curing temperatures.Occlusal surfaces of 44 human molars were ground with diamond burs under water coolant and polished with 600 grit silicon carbide papers to obtain flat dentin surfaces. The dentin was etched with 37% phosphoric acid and bonded with Adper Single Bond 2 according to the manufacturer's instructions. The specimens were randomly divided into two groups (n=22 according to the composite resin applied: FiltekP60 and Filtek Z250. Each group included three subgroups of composite resin pre-curing temperatures (4°C, 23°C and 37°C. Composite resins were applied to the dentin surfaces in a plastic mold (8mm in diameter and 4mm in length incrementally and cured. Twenty-two composite-to-dentin hour-glass sticks with one mm(2 cross-sectional area per group were prepared. Microtensile bond strength measurements were made using a universal testing machine at a crosshead speed of one mm/min. For statistical analysis, t-test, one-way and two-way ANOVA were used. The level of significance was set at P<0.05.Filtek P60 pre-heated at 37ºC had significantly higher microtensile bond strength than Filtek Z250 under the same condition. The microtensile bond strengths were not significantly different at 4ºC, 23ºC and 37ºC subgroups of each composite resin group.Filtek P60 and Filtek Z250 did not have significantly different microtensile bond strengths at 4ºC and 23ºC but Filtek P60 had significantly higher microtensile bond strength at 37 ºC. Composite and temperature interactions had significant effects on the bond strength.

  5. Effects of preheating and precooling on the hardness and shrinkage of a composite resin cured with QTH and LED.

    Science.gov (United States)

    Osternack, F H; Caldas, D B M; Almeida, J B; Souza, E M; Mazur, R F

    2013-01-01

    The aim of this study was to evaluate in vitro the hardness and shrinkage of a pre-cooled or preheated hybrid composite resin cured by a quartz-tungsten-halogen light (QTH) and light-emitting diode (LED) curing units. The temperature on the tip of the devices was also investigated. Specimens of Charisma resin composite were produced with a metal mold kept under 37°C. The syringes were submitted to 4°C, 23°C, and 60°C (n=20) before light-curing, which was carried out with the Optilux 501 VCL and Elipar FreeLight 2 units for 20 seconds. The specimens were kept under 37°C in a high humidity condition and darkness for 48 hours. The Knoop hardness test was carried out with a 50 gram-force (gf) load for 10 seconds, and the measurement of the shrinkage gap was carried out using an optical microscope. The data were subjected to analysis of variance and the Games-Howell test (α=0.05). The mean hardness of the groups were similar, irrespective of the temperatures (p>0.05). For 4°C and 60°C, the top surface light-cured by LED presented significantly reduced shrinkage when compared with the bottom and to both surfaces cured by QTH (phardness was not affected by pre-cooling or preheating. However, polymerization shrinkage was slightly affected by different pre-polymerization temperatures. The QTH-curing generated greater shrinkage than LED-curing only when the composite was preheated. Different temperatures did not affect the composite hardness and shrinkage when cured by a LED curing unit.

  6. A Generalized and Simple Numerical Model to Compute the Feed Water Preheating System for Steam Power Plants

    Directory of Open Access Journals (Sweden)

    Ioana Opriș

    2017-02-01

    Full Text Available A general and simple numerical model is presented to calculate the uncontrolled steam flows extracted from a turbine to preheat the feed-water of a steam generator. For a user-defined technological scheme, a set of clear rules is given to complete the elements of the augmented matrix of the linear system that solves the problem. The model avoids writing of the heat balance equations for each heat exchanger. The steam extractions to the heaters are determined as related to the flow rate at the condenser. A numerical example is given to show the results.

  7. Effects of target pre-heating and expansion on terahertz radiation production from intense laser-solid interactions

    Institute of Scientific and Technical Information of China (English)

    X.H.Yuan; Y.Fang; D.C.Carroll; D.A.MacLellan; F.Du; N.Booth; M.Burza; M.Chen; R.J.Gray; Y.F.Jin; Y.T.Li; Y.Liu; D.Neely; H.Powell; G.Scott; C.-G.Wahlstrm; J.Zhang; P.McKenna; Z.M.Sheng

    2014-01-01

    The first experimental measurements of intense(~7 × 1019 W cm-2) laser-driven terahertz(THz) radiation from a solid target which is preheated by an intense pulse of laser-accelerated protons is reported. The total energy of the THz radiation is found to decrease by approximately a factor of 2 compared to a cold target reference. This is attributed to an increase in the scale length of the preformed plasma, driven by proton heating, at the front surface of the target,where the THz radiation is generated. The results show the importance of controlling the preplasma scale length for THz production.

  8. Influence of pre-heat treatment and different light-curing units on Vickers hardness of a microhybrid composite resin

    Science.gov (United States)

    Saade, E. G.; Bandeca, M. C.; Rastelli, A. N. S.; Bagnato, V. S.; Porto-Neto, S. T.

    2009-06-01

    The aim of this study was to evaluate the hardness of a dental composite resin submitted to temperature changes before photo-activation with two light-curing unite (LCUs). Five samples (4 mm in diameter and 2 mm in thickness) for each group were made with pre-cure temperatures of 37, 54, and 60°C. The samples were photo-activated with a conventional quartz-tungsten-halogen (QTH) and blue LED LCUs during 40 s. The hardness Vickers test (VHN) was performed on the top and bottom surfaces of the samples. According to the interaction between light-curing unit and different pre-heating temperatures of composite resin, only the light-curing unit provided influences on the mean values of initial Vickers hardness. The light-curing unit based on blue LED showed hardness mean values more homogeneous between the top and bottom surfaces. The hardness mean values were not statistically significant difference for the pre-cure temperature used. According to these results, the pre-heating of the composite resin provide no influence on Vickers hardness mean values, however the blue LED showed a cure more homogeneous than QTH LCU.

  9. Effect of preheating on the damage to tungsten targets after repetitive ITER ELM-like heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Makhlay, V A [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Bandura, A N [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Byrka, O V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Garkusha, I E [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Chebotarev, V V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Tereshin, V I [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Landman, I [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany)

    2007-03-15

    The behaviour of a preheated tungsten target under repetitive pulsed plasma impacts of the energy density 0.75 MJ m{sup -2} with the pulse duration of 0.25 ms was studied with the quasi-stationary plasma accelerator (QSPA) Kh-50. Two identical samples of pure sintered tungsten have been exposed to numbers of pulses exceeding 100. One sample was maintained at room temperature and the other sample preheated at 650 deg. C. The experiments demonstrated that on the cold surface some macro-cracks dominate, but on the hot surface they do not develop. However, in both cases some fine meshes of micro-cracks are observed. With increasing the number of exposures, the width of the micro-cracks gradually increases, achieving 0.8-1.5 {mu}m after 100 pulses. In addition, the SEM shows some cellular structure with the cell sizes about 0.3 {mu}m, and after large numbers of exposures some blisters of sizes up to 100-150 {mu}m appear.

  10. 预热工艺对钢化玻璃性能的影响%Influence of Preheating Process on Tempered Glass Properties

    Institute of Scientific and Technical Information of China (English)

    赵旭东; 张晓娟

    2015-01-01

    Preheat under different conditions (other things being equal), double chamber strong convection horizontal tempering furnace was carried out on 6mm clear glass tempered processing, analyzed the effects of preheating parameters on the performance of the tempered glass, and the results are discussed.%在不同的预热条件(其它条件相同)下,利用双室强对流水平钢化炉对6 mm白玻进行钢化处理,分析了预热参数对钢化玻璃性能的影响,并对结果进行了讨论.

  11. Transpired Solar Collector at NREL's Waste Handling Facility Uses Solar Energy to Heat Ventilation Air (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-09-01

    The transpired solar collector was installed on NREL's Waste handling Facility (WHF) in 1990 to preheat ventilation air. The electrically heated WHF was an ideal candidate for the this technology - requiring a ventilation rate of 3,000 cubic feet per meter to maintain safe indoor conditions.

  12. Effects of preheating of crude palm oil (CPO) on injection system, performance and emission of a diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Bari, S.; Lim, T.H.; Yu, C.W. [Universiti Sains Malaysia, School of Mechanical Engineering, Penang (Malaysia)

    2002-11-01

    Crude palm oil (CPO) is one of the vegetable oils that have potential for use as fuels for diesel engines. CPO is renewable, and is safe and easy to handle. However, at room temperature (30-32 deg C) CPO has a viscosity about 10 times higher than that of diesel. To lower CPO's viscosity to the level of diesel's viscosity, a heating temperature of at least 92 deg C is needed. At this temperature, there is a concern that the close-fitting parts of the injection system might be affected. This study focused on finding out the effects of preheating of fuel on the injection system utilising a modified method of friction test, which involves injecting fuel outside the combustion chamber during motoring. Results show that preheating of CPO lowered CPO's viscosity and provided smooth fuel flow, but did not affect the injection system, even heating up to 100 deg C. Nevertheless, heating up to such a high temperature offered no benefits in terms of engine performance. However, heating is necessary for smooth flow and to avoid fuel filter clogging. Both can be achieved by heating CPO to 60 deg C. Combustion analyses comparisons between CPO and diesel found that CPO produced a higher peak pressure of 6%, a shorter ignition delay of 2.6 deg, a lower maximum heat release rate and a longer combustion period. Over the entire load range, CPO combustion produced average CO and NO emissions that were 9.2 and 29.3% higher, respectively, compared with those from diesel combustion. (Author)

  13. Numerical Simulation of Combustion Characteristics in High Temperature Air Combustion Furnace

    Institute of Scientific and Technical Information of China (English)

    WANG Ai-hua; CAI Jiu-ju; XIE Guo-wei

    2009-01-01

    The influences of air preheating temperature, oxygen concentration, and fuel inlet temperature on flame properties, and NOx formation and emission in the furnace were studied with numerical simulation. The turbulence behavior was modeled using the standard k-e model with wall function, and radiation was handled using discrete ordi-nate radiation model. The PDF (probability density funetion)/mixture fraction combustion model was used to simu-late the propane combustion. Additionally, computations of NOx formation rates and NOx concentration were carried out using a post-processor on the basis of previously calculated velocities, turbulence, temperature, and chemical composition fields. The results showed that high temperature air combustion (HiTAC) is spread over a much larger volume than traditional combustion, flame volume increases with a reduction of oxygen eoncentration, and this trend is clearer if oxygen concentration in the preheated air is below 10%. The temperature profile becomes more uniform when oxygen concentration in preheated air decreases, especially at low oxygen levels. Increase in fuel inlet tempera-ture lessens the mixing of the fuel and air in primary combustion zone, ereates more uniform distribution of reactants inside the flame, decreases the maximum temperature in furnace, and reduces NOx emission greatly.

  14. Investigation of a hybrid PVT air collector system

    Science.gov (United States)

    Haddad, S.; Touafek, K.; Mordjaoui, M.; Khelifa, A.; Tabet, I.

    2017-02-01

    The photovoltaic thermal hybrid (PVT) collectors, which simultaneously produce electricity and heat, are an alternative to photovoltaic modules and thermal collectors installed separately. Indeed, the heat extracted from the solar cell is used to heat water or air, thereby cooling the cell, and thus increasing its energy efficiency. This paper deals with a hybrid PVT air collector in which a new design has been proposed and tested. Its principle is based on the return of the preheating air to a second heating. The air thus passes twice under the solar cells before being evacuated to the outside of the collector (for space heating). The system is modular and expandable to cover large spaces to be heated. The experimental results of this novel design are presented and discussed under both normal and forced circulation. This technique of air return shows favorable results in terms of the quality of the heated air and electric power generation.

  15. 预热工艺对钢化玻璃性能的影响%Influence of Preheating Process on the Properties of Tempered Glass

    Institute of Scientific and Technical Information of China (English)

    赵旭东

    2015-01-01

    6mm clear glass produced by TAMGLASS Company was processed to be tempered glass by the double chamber hori-zontal tempering furnace production line. The conditions of different preheating ( such as preheat temperature, the up/down convec-tion) on the properties of tempered glass were studied. By adjusting the different parameters of preheating and measurement of tem-pered glass bending, tempered parameters, the paper analyzes the effects of preheating parameters on the performance of the tem-pered glass, and the results are discussed. Results show that the parameters such as preheat temperature, preheat convection en-hance the substrate temperature of glass in the heating period of heat to be faster, better heat evenly;it enhances the smoothness of tempered glass and the apparent quality of the final product has obviously improved. Through the optimal parameter combination, glass products with a group of excellent properties are toughened.%利用TAMGLASS公司生产的双室强对流水平钢化炉生产线对南玻公司生产的6 mm白玻璃进行了钢化处理,研究了不同预热条件(预热温度、上下对流设置等)对钢化玻璃性能的影响。通过调整不同的预热参数以及测量钢化后的玻璃弯曲度、钢化应力、表观质量等参数,分析了预热参数对钢化玻璃性能的影响,并对实验结果进行了讨论。结果表明:设置合适的预热温度、预热对流等参数可提高玻璃的基体温度,使得玻璃在加热段的加热更快、受热更加均匀,提高了钢化玻璃的平整度,对最终产品的表观质量有明显改善。

  16. Using pre-heated sunflower oil as fuel in a diesel cycle engine

    Energy Technology Data Exchange (ETDEWEB)

    Delalibera, H.C.; Neto, P.H.W.; Martini, J. [State Univ. of Ponta Grossa (Brazil)

    2010-07-01

    This paper reported on a study in which 100 per cent sunflower oil was used in a tractor to compare its performance with petroleum diesel. Work trials were carried out for 50 hours on a single cylinder direct injection micro-tractor. In the first trial (E-1), the temperature of the vegetable oil was the same as the air temperature of the engine, while in the second trial (E-2), the oil was heated to a temperature of about 90 degrees C. Only petrodiesel was used in the third (E-3) trial. The head gasket burned in the first test after 50 hours of operation. An increase in compression was noted during trials E-1 and E-2. The carbonized mass in the nozzle of the E-2 trial was 81.5 per cent lower than in the E-1 trial. The carbonized mass in the intake system of the E-2 trial was 51.7 per cent lower than in the E-1 trial. The exhaust system of the E-2 trial was 33.4 per cent lower than that of the E-1 trial. For the combustion chamber, the carbonization of the E-1 trial was nearly the same as in the E-2 trial. The hourly fuel consumption of the E-1 trial was 2.3 per cent higher than petrodiesel, while E-2 trial was 0.7 per cent higher than petrodiesel. In the first 2 tests, the lubricating oil was contaminated by vegetable oil fuel. In general, results from the first trial were better than results from the second trial.

  17. 提高蒸馏醪液预热温度的研究%Improvement of Distilled Mash Preheat Temperature

    Institute of Scientific and Technical Information of China (English)

    郭传广; 何松贵; 卫云路

    2016-01-01

    In order to improve the distillation efficiency, reduce energy consumption through the transformation of existing retort, increasing the heat transfer area of the heat exchanger, so be distilled mash temperature than the original improved 45.3%, 7.5 single retort distillation save time min, to achieve annual savings of 7.26%of steam. Further, the test vegetarian tasting that wine quality, to improve the preheating temperature of the mash vegetarian wine quality has little effect on stability vegetarian wine quality.%为了提高蒸馏效率,降低能耗,通过对现有蒸馏甑进行改造,增大了换热器的换热面积,使得待蒸馏的醪液温度较原来的提升了45.3%,单甑蒸馏节约时间7.5min,全年可实现节约蒸汽7.26%。另外,通过对试验斋酒质量的品评得知,提高醪液预热温度对斋酒质量影响不大,斋酒质量稳定。

  18. Assessing the 2{omega}{sub pe} instability and other preheat considerations in ignition-scale hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W L [University of California, Davis, Davis, CA 95616 (United States); Meezan, Nathan; Town, Richard; Strozzi, David; Wilks, Scott; Williams, Edward; Meeker, Donald; Suter, L S [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Regan, S P, E-mail: wlkruer@ucdavis.ed [Laboratory for Laser Energetics, Rochester, NY 14623 (United States)

    2010-08-01

    In recent experiments[1] Sean Regan, et. al. for the first time observed the 2{omega}{sub pe} instability from window plasma in hohlraum targets. This instability can also operate[2] at peak power near the edge of the inner beams in the ablator plasma and near the edge of the outer beams in the liner plasma. Fortunately only a small fraction of the laser energy was estimated to be at risk. A more quantitative assessment of the energy at risk at peak power will here be given. We show that the instability threshold can be significantly reduced for laser beams with an angle of incidence of about 60 degrees due to the swelling of the laser field near its turning point. A simple model is given. It is also shown that for frequently cited plasma conditions, the Raman-scattered light wave can itself drive the 2{omega}{sub pe}instability. This effect is relevant for the nonlinear saturation of stimulated Raman scattering (SRS) and the resulting heated electron generation. Some estimates are given. Finally we conclude with a few remarks about hot electron preheat.

  19. The effect of pre-heating silorane and methacrylate-based composites on microleakage of Class V restorations

    Directory of Open Access Journals (Sweden)

    Soley Arslan

    2012-01-01

    Full Text Available Objective: This study compared the effects of 4 different temperatures (4°C, 25°C, 37°C, 60°C on the microleakage of silorane and methacrylate-based composites in Class V cavities. Materials and Methods: Standard Class V cavities were prepared at the buccal and lingual surfaces of human molars. The specimens were randomly divided into 2 groups according to the composite resin used (Group I: Filtek Silorane Adhesive System and Filtek Silorane composite; Group II: Clearfil SE Bond and Aelite LS Posterior composite and into 4 subgroups according to temperature treatment (Group A: Refrigeration at 4°C; Group B (control: Storage at room temperature (25°C; Group C: Heated to 37°C and Group D: Heated to 60°C using Calset. Specimens were dyed with 0.5% basic fuchsin, sectioned, and evaluated at 25x magnification. Statistical analysis was performed using Mann-Whitney U and Kruskal-Wallis tests at P0.05. Differences in temperature did not significantly affect microleakage values for Filtek Silorane (P>0.05; however, microleakage values of Aelite LS Posterior composite varied according to temperature treatment, with heating resulted in significantly less microleakage than cooling (between Groups IID and IIA and Groups IIC and IIA (P<0.05. Conclusion: Pre-heating was shown to reduce microleakage values of Aelite LS Posterior composite, but did not significantly alter the microleakage values of Filtek Silorane composite.

  20. Investigation of Preheat Temprature Effect on the Sturcture of Functionally Graded Ni3Al/NiAl/NiTi Intermetallic Compound

    Directory of Open Access Journals (Sweden)

    Musa Kılıç

    2015-12-01

    Full Text Available In this study, a functional graded material (FGM consisted of NiTi NiAl and Ni3Al were manufactured by self-propagating high-temperature synthesis (SHS technique. These three different compound powders were mixed in a rotating container after accurately weighed and cold compacted under 200 MPa pressure. These pressed samples were produced for 200, 300 and 400 ° C preheating temperature by igniting with high voltage under argon gas atmosphere. The microstructures of these functional graded materials were examined by microscopy, Scanning Electron Microscopy (SEM and X-Ray Diffraction (XRD. Consequently, functional graded material successful generated by SHS in every three preheating temperature and the metallic desired compounds were obtained but, it was seen that apart from the main phases in the intersection there are other phases with more melting and gaps.

  1. Exploiting the use of compact heat exchangers on preheating trains; Avaliacao de desempenho de trocadores compactos em bateria de pre-aquecimento - REDUC

    Energy Technology Data Exchange (ETDEWEB)

    Villas Boas, Alan Trugilho; Bolsoni, Adair [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Refinaria de Duque de Caxias (REDUC); Kuboski, Claudio; Cesario, Diomedes [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    The U-1210 distillation unit of Holding has being expected to suffer a metallurgical adaptation in order to process petroleum with higher naphthenic acids concentration. A heat integration study (pinch analysis) was realized, with the restriction of limited plot area and shut-down time. A full compabloc preheat train was preliminary concept. During conceptual design, REDUC found it to be a good idea to have a performance test. A compabloc CP30 unit has been installed, in order to evaluate the performance of this equipment under unit conditions. The operation service chosen was vacuum residue preheating crude before the dessalter, low crude temperature (100 deg C to 115 deg C). The objective was operational and maintenance experience. (author)

  2. Implications of Halo Inside-out Growth on the X-Ray Properties of Nearby Galaxy Systems within the Preheating Scenario

    CERN Document Server

    Solanes, J M; Gonzalez-Casado, G; Salvador-Solé, E; Solanes, Jose M.; Manrique, Alberto; Gonzalez-Casado, Guillermo; Salvador-Sole, Eduard

    2005-01-01

    We present an entirely analytic model for a preheated, polytropic intergalactic medium in hydrostatic equilibrium within a NFW dark halo potential in which the evolution of the halo structure between major merger events proceeds inside-out by accretion. This model is used to explain, within a standard $\\Lambda$CDM cosmogony, the observed X-ray properties of nearby relaxed, non-cooling flow groups and clusters of galaxies. We find that our preferred solution to the equilibrium equations produces scaling relations in excellent agreement with observations, while simultaneously accounting for the typical structural characteristics of the distribution of the diffuse baryons. In the class of preheating models, ours stands out because it offers a unified description of the intrahalo medium for galaxy systems with total masses above $\\sm 2\\times 10^{13}$\\msun, does not produce baryonic configurations with large isentropic cores, and reproduces faithfully the observed behavior of the gas entropy at large radii. All th...

  3. Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions

    Science.gov (United States)

    Wang, Y.; Gupta, A. K.

    2001-01-01

    The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

  4. Effect of pre-heated dual-cured resin cements on the bond strength of indirect restorations to dentin

    Directory of Open Access Journals (Sweden)

    Alexandre Morais

    2012-04-01

    Full Text Available This study evaluated the effects of resin luting agents (LA polymerized using increased temperature on the in vitro microtensile bond strength (mTBS of indirect restorations to dentin. The occlusal dentin surfaces of 40 human third molars were exposed and flattened. The teeth were assigned to 8 groups (n = 5 according to the LA temperature (25°C o r 50°C, curing mode (dual- or self-curing mode, and product (Excite DSC/Variolink II [VII] and XP Bond/Calibra [Cal]. The bonding agents were applied to the dentin surfaces according to manufacturers' instructions. For preheated groups, the LAs were heated to 50°C, subsequently mixed on a heated stirrer surface, and applied to the previously heated pre-polymerized resin discs (2 mm thickness, TPH-Spectrum. The discs were bonded to the dentin surfaces, and the LAs were either exposed to a curing light according to manufacturers' instructions or allowed to self-cure. Specimens were stored in relative humidity at 37°C for 7 days. Specimens were mesio-distally and bucco-lingually sectioned to obtain multiple bonded beams with a 1-mm² cross-sectional area for mTBS testing. Data (MPa were analyzed by 2-way ANOVA and Tukey's post hoc test (a = 5% for each product. Specimen failure patterns were analyzed using a scanning electron microscope. VII groups showed higher mTBS at 50°C than at 25°C regardless of curing mode (p = 0.05. Cal groups showed similar mTBS at 25°C and 50°C in all activation modes. The use of some dual-polymerizing LAs at 50°C may improve the mTBS of indirect restorations to dentin.

  5. First Results from Laser-Driven MagLIF Experiments on OMEGA: Backscatter and Transmission Measurements of Laser Preheating

    Science.gov (United States)

    Davies, J. R.; Barnak, D. H.; Betti, R.; Chang, P.-Y.

    2015-11-01

    A laser-driven version of MagLIF (magnetized liner inertial fusion) is being developed on the OMEGA laser. In the first experiment, laser preheating with a single OMEGA beam was studied. Laser energies of 60 to 200 J in 2.5-ns-long pulses were used, with a distributed phase plate giving a Gaussian intensity profile with a 96 μm full width at half maximum. We report on backscatter measurements from gas-filled cylinders and both backscatter and transmission measurements from the 1.84- μm-thick polyimide foils used for the laser entrance windows. Backscatter spectra and energies from both cylinders and foils alone were very similar. Approximately 0.5% of the total incident laser energy was backscattered. Backscattering lasted for little more than 0.5 ns. The fraction of laser energy transmitted through foils within the original beam path increased from 50% to 64% as the laser energy was increased from 60 to 200 J. Up to 10% of the laser energy was sidescattered as the foil started to transmit. Sidescattering of transmitted light lasted ~0.5 ns. The sidescattering might be avoided by using a short prepulse at least 0.5 ns prior to the main pulse. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and by DE-FG02-04ER54786 and DE-FC02-04ER54789 (Fusion Science Center).

  6. Effect of Preheating and Precooling on the Flexural Strength and Modulus of Elasticity of Nanohybrid and Silorane-based Composite

    Directory of Open Access Journals (Sweden)

    Farahnaz Sharafeddin

    2015-09-01

    Full Text Available Statement of the Problem: Composite resin may be used in different temperatures; it is crucial to determine the effect of temperature on mechanical properties of nanohybrid and silorane-based composite. Purpose: This in vitro study compared the flexural strength and modulus of elasticity of nanohybrid and silorane-based resin composite, at 4˚C, room temperature (25˚C, and 45˚C. Materials and Method: In this experimental study, 60 specimens were prepared in a metal split mold (2×2×25mm. Two different resin composites, Filtek Z250 XT (3M/ ESPE and Filtek P90 (3M/ESPE, were evaluated. The material were inserted into split molds at room temperature, 4˚C or 45˚C and cured with LED (1200 mW/cm2 for 20 seconds in four points (n=10. Then, a three-point bending test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min for measuring the flexural strength and flexural modulus of samples. The data were analyzed by the two-way ANOVA and Tukey test (p< 0.05. Results: The mean highest flexural strength was observed at 45˚C, showing statistically significant difference with flexural strength at 4˚C (p= 0.0001 and 25˚C (p= 0.003 regardless of the type of resin composite. The flexural modulus at 45˚C was highest, showing the statistically significant difference with flexural modulus at 4˚C (p= 0.0001 and 25˚C (p= 0.002. The flexural modulus was statistically different between nanohybrid and silorane-based resin composite (p= 0.01 in 25˚C and 45˚C, but there were no statistically significant differences between flexural strength of Filtek Z250 XT and Filtek P90 regardless of the temperatures (p= 0.062. Conclusion: Preheating the resin composite at 45˚C improves flexural strength and modulus of nanohybrid and silorane-based resin composite. However, flexural strength and modulus of the tested materials were not affected by precooling. The flexural modulus of nanohybrid resin composite was significantly higher than

  7. Combustion-driven oscillation in a furnace with multispud-type gas burners. 4th Report. Effects of position of secondary air guide sleeve and openness of secondary air guide vane on combustion oscillation condition; Multispud gata gas turner ni okeru nensho shindo. 4. Nijigen kuki sleeve ichi oyobi nijigen kuki vane kaido no shindo reiki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, I.; Okiura, K.; Baba, A.; Orimoto, M. [Babcock-Hitachi K.K., Tokyo (Japan)

    1994-07-25

    Effects of the position of a secondary air guide sleeve and the openness of a secondary air guide vane on combustion oscillation conditions were studied experimentally for multispud-type gas burners. Pressure fluctuation in furnaces was analyzed with the previously reported resonance factor which was proposed as an index to represent the degree of combustion oscillation. As a result, the combustion oscillation region was largely affected by both position of a guide sleeve and openness of a guide vane. As the openness having large effect on the ratio of primary and secondary air/tertiary air and the position hardly having effect on the ratio were adjusted skillfully, the burner with no combustion oscillation region was achieved in its normal operation range. In addition, as the effect of preheating combustion air was arranged with a standard flow rate or mass flow flux of air, it was suggested the combustion oscillation region due to preheating can be described with the same manner as that due to no preheating. 5 refs., 8 figs.

  8. An Analysis of the Microstructure, Macrostructure and Microhardness of Nicr-Ir Joints Produced by Laser Welding with and without Preheat

    Directory of Open Access Journals (Sweden)

    Różowicz S.

    2016-06-01

    Full Text Available This paper discusses some of the basic problems involved in laser welding of dissimilar materials with significant differences in melting points. It focuses on the micro and macrostructure of laser welded NiCr-Ir microjoints used in central spark plug electrodes. The joints were produced by welding with and without preheat using an Nd,YAG laser. The structure and composition of the welded joints were analyzed by means of a light microscope (LM and a scanning electron microscope (SEM equipped with an energy dispersive X-ray (EDX spectrometer. The microhardness of the weld area was also studied.

  9. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  10. Experimental data and boundary conditions for a Double-Skin Facade building in external air curtain mode

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Jensen, Rasmus Lund

    ’. This covers such problem areas as measurements of naturally induced air flow, measurements of air temperature under direct solar radiation exposure, etc. Finally, in order to create a solid foundation for software validation, the uncertainty and limitations in the experimental results are discussed. In part...... was carried out in a full scale test facility ‘The Cube’, in order to compile three sets of high quality experimental data for validation purposes. The data sets are available for preheating mode, external air curtain mode and transparent insulation mode. The objective of this article is to provide the reader...

  11. Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

    Directory of Open Access Journals (Sweden)

    Giovanni Angrisani

    2016-09-01

    Full Text Available In this paper, three alternative layouts (scenarios of an innovative solar-assisted hybrid desiccant-based air handling unit (AHU are investigated through dynamic simulations. Performance is evaluated with respect to a reference system and compared to those of the innovative plant without modifications. For each scenario, different collector types, surfaces and tilt angles are considered. The effect of the solar thermal energy surplus exploitation for other low-temperature uses is also investigated. The first alternative scenario consists of the recovery of the heat rejected by the condenser of the chiller to pre-heat the regeneration air. The second scenario considers the pre-heating of regeneration air with the warmer regeneration air exiting the desiccant wheel (DW. The last scenario provides pre-cooling of the process air before entering the DW. Results reveal that the plants with evacuated solar collectors (SC can ensure primary energy savings (15%–24% and avoid equivalent CO2 emissions (14%–22%, about 10 percentage points more than those with flat-plate collectors, when the solar thermal energy is used only for air conditioning and the collectors have the best tilt angle. If all of the solar thermal energy is considered, the best results with evacuated tube collectors are approximately 73% in terms of primary energy saving, 71% in terms of avoided equivalent CO2 emissions and a payback period of six years.

  12. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  13. Humid Air Turbine as a Primary Link of a Coal-Fired Steam Power Plant

    Directory of Open Access Journals (Sweden)

    Jan T. Szargut

    2000-06-01

    Full Text Available Outlet gases of the humid air turbine (having a temperature of about 125 oC and great content of steam can be used for the preheating of feed water of the steam power plant fueled with coal. So the efficiency of the plant can be increased and its ecological indices can be improved. The attainable incremental efficiency of the humid air turbine and the increased efficiency of the combined plant has been determined for three variants of the repowering of an existing steam power plant. The variant presented in Figure 4 is recommended for practical application.

  14. Analysis of Unsteady Heat Exchange of Rotary Air Preheaters%回转式空气预热器非稳定换热的分析

    Institute of Scientific and Technical Information of China (English)

    冷伟; 陈曦; 于翔; 王渡

    2006-01-01

    根据回转式空气预热器的工作机理,分析了非稳定换热对其热力计算的影响,详细介绍了所建立的非稳定换热的计算模型,模型反映了空气预热器的转速、受热面的质量和比热、烟气和空气的流量和比热、各分仓的角度和受热面积、传热系数等诸多因素对非稳定换热的影响.以烟气和空气的流量、传热系数以及受热面动态热容的改变为例,给出了非稳定换热影响系数和受热面温度发生相应变化的计算结果.分析了各类因素的影响程度大小和模型的合理性.与目前仅根据空气预热器转速,插值计算非稳定换热影响系数的方法相比,该模型具有更好的合理性和广泛适用性.图6参5

  15. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    Science.gov (United States)

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry ( 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  16. Development of an expert system for preheating temperatures determination. Desarrollo dse uns sistema experto para la determinacion de temperatura de precalentamiento

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, E.; Silva, M.; Gonalvez, P.; Fernandez, A.A. (Oporto Univ. (Portugal) Facultad de Ingenieria)

    1989-01-01

    This work describes the development of an expert system designed to control the cold fissuration phenomenon caused by H{sup 2} on welded joints of carbonated, C-Mn and light alloy steels, obtained through fusion welding (manual electric arc, MIG/MAG, TIG and submerged arc). This system, implemented in PROLOG language, allows a quick and simple calculation of preheating temperatures. The aim of this system, which does not require programming knowledge to be updated, is to help welding engineers to design welding procedures which are safe as regards to the joint resistance to cold fissuration. Being an expert system, the user has the opportunity to obtain interactive explanations about the way any conclusions are obtained, as well as information about the concepts and parameters on which the reasoning is based.(Author)

  17. Combination Effect of Dry-Ice Blasting and Substrate Preheating on Plasma-Sprayed CoNiCrAlY Splats

    Science.gov (United States)

    Dong, Shujuan; Song, Bo; Hansz, Bernard; Liao, Hanlin; Coddet, Christian

    2013-02-01

    CoNiCrAlY splats were plasma-sprayed on the stainless steel substrate which was pretreated by dry-ice blasting. Only impact marks were distinguished on the glycerol-polluted substrate, while halo donut splats formed on the pretreated substrate because of the cleaning effect of dry-ice blasting on this organic substance. The proportions of different splat types vary as a function of the treatment time of dry-ice blasting. The condensation phenomenon was also detected on the substrate surface accompanying the cleaning effect after the pretreatment of dry-ice blasting. In this study, dry-ice blasting was investigated to be coupled with substrate preheating to control the substrate temperature. It was found that a regular disk-like CoNiCrAlY splat can be obtained as the substrate temperature is higher than dew point temperature.

  18. Performance Evaluation of Photovoltaic Solar Air Conditioning

    Directory of Open Access Journals (Sweden)

    Snegirjovs A.

    2016-12-01

    Full Text Available Information on the electrical-driven solar air conditioning (SAC is rather scanty. A considerable body of technical data mostly concerns large-scale photo-voltaic solar air conditioning (PV-SAC systems. Reliable information about the energy output has arisen only in recent years; however, it is still not easily accessible, and sometimes its sources are closed. Despite these facts, solar energy researchers, observers and designers devote special attention to this type of SAC systems. In this study, performance evaluation is performed for the PV-SAC technology, in which low-power (up to 15 kWp of cooling power on average systems are used. Such a system contains a PV electric-driven compression chiller with cold and heat sensible thermal storage capacities, and a rejected energy unit used for preheating domestic hot water (DHW. In a non-cooling season, it is possible to partly employ the system in the reverse mode for DHW production. In this mode, the ambient air serves as a heat source. Besides, free cooling is integrated in the PV-SAC concept.

  19. Performance Evaluation of Photovoltaic Solar Air Conditioning

    Science.gov (United States)

    Snegirjovs, A.; Shipkovs, P.; Lebedeva, K.; Kashkarova, G.; Migla, L.; Gantenbein, P.; Omlin, L.

    2016-12-01

    Information on the electrical-driven solar air conditioning (SAC) is rather scanty. A considerable body of technical data mostly concerns large-scale photo-voltaic solar air conditioning (PV-SAC) systems. Reliable information about the energy output has arisen only in recent years; however, it is still not easily accessible, and sometimes its sources are closed. Despite these facts, solar energy researchers, observers and designers devote special attention to this type of SAC systems. In this study, performance evaluation is performed for the PV-SAC technology, in which low-power (up to 15 kWp of cooling power on average) systems are used. Such a system contains a PV electric-driven compression chiller with cold and heat sensible thermal storage capacities, and a rejected energy unit used for preheating domestic hot water (DHW). In a non-cooling season, it is possible to partly employ the system in the reverse mode for DHW production. In this mode, the ambient air serves as a heat source. Besides, free cooling is integrated in the PV-SAC concept.

  20. 采用感应预热的连续激光淬火%Continuous Laser Hardening with Induction Pre-Heating

    Institute of Scientific and Technical Information of China (English)

    I Doležel; V.Kotlan; R.Hamar; D.Pánek

    2015-01-01

    A novel way of continuous surface hardening of steel bodies by a laser beam is modeled.This heat treatment is supplemented with pre-heating of the hardened parts by a classic inductor in order to reduce the temperature gradients and subsequent mechanical stresses in the processed material.The mathematical model of the process is solved numerically in 3D and the solution respects all important nonlinearities (a saturation curve of the hardened steel and temperature dependences of its physical properties).The methodology is illustrated with a typical example,whose results are presented and discussed.%模拟了钢件采用激光束进行表面连续淬火的新方法。这种热处理方法采用传统的感应器对淬火零件进行预热,以便减小温度梯度及随后产生的被处理材料的机械应力。该工艺的数学模型采用3D数值建立,其解法考虑了所有重要的非线性特性(被淬火钢的磁饱和曲线及其物理性能与温度的关系)。用典型的实例进行了说明,介绍了结果并进行了讨论。

  1. Research of Infrared Preheating Vibration Friction Welding Technology for Plastic%塑料红外预加热振动摩擦焊接技术研究

    Institute of Scientific and Technical Information of China (English)

    刘勇; 李朝晖; 朱彩萍

    2012-01-01

    比较了红外预加热振动摩擦焊接技术即清洁摩擦焊接技术(CVT)相对于传统塑料焊接技术的优势,论述了CVT的原理,并对CVT的可行性和实际应用进行了分析.结果表明,CVT可大幅改善塑料焊接件的外观质量,减少焊接过程中的颗粒排放并提高其焊接强度,是一种清洁高效的新型塑料焊接技术.%Advantages of infrared preheating vibration friction welding technology which also was known as clean vibration friction welding technology ( CVT) were compared with traditional plastic welding technologies, and the theory of CVT was expounded, then the feasibility and practical application of CVT were analyzed. The results showed that CVT could improve the appearance quality of plastic welding parts substantially, decrease the participate emission during the welding process and increase the welding strength. It indicated that CVT was a new kind of plastic welding technology with clean and high efficiency.

  2. Demonstration of the Performance of an Air-Type Photovoltaic Thermal (PVT System Coupled with a Heat-Recovery Ventilator

    Directory of Open Access Journals (Sweden)

    Jin-Hee Kim

    2016-09-01

    Full Text Available A heat-recovery ventilator (HRV effectively conducts ventilation by recovering waste heat from indoors to outdoors during heating periods. However, dew condensation associated with the HRV system may arise due to the difference between the indoor temperature and the very low outdoor temperature in winter, and this can decrease the heat exchange efficiency. These problems can be solved by the pre-heating of the incoming air, but additional energy is required when pursuing such a strategy. On the other hand, an air-type photovoltaic thermal (PVT system produces electricity and thermal energy simultaneously using air as the heat transfer medium. Moreover, the heated air from the air-type PVT system can be connected to the HRV to pre-heat the supply air instead of taking in the cold outdoor air. Thus, the ventilation efficiency can be improved and the problems arising during the heating period can be resolved. Consequentially, the heating energy required in a building can be reduced, with additional electricity acquired as well. In this paper, the performance of an air-type PVT system coupled with an HRV is assessed. To do this, air-type PVT collectors operating at 1 kWp were installed in an experimental house and coupled to an HRV system. Thermal performance and heating energy required during the winter season were analyzed experimentally. Furthermore, the electrical performances of the air-type PVT system with and without ventilation at the back side of the PV during the summer season were analyzed.

  3. 带废钢预热电弧炉烟气中的二(口恶)英的产生及抑制%The Dioxin Producing and Restraint in Fume from EAF during Scrap Preheat

    Institute of Scientific and Technical Information of China (English)

    侯祥松

    2011-01-01

    The dioxin producing mechanism in EAF, especially the dioxin producing mechanism in EAF with scrap preheat is analyzed. It is shown that the scrap preheat will induce significant increment of dioxin in the fume. Some special methods should be adopted during design as scrap sorting controlling the fume temperature after scrap preheat, spraying lime, quickening cooling velocity in waste heat boiler. The dioxin deprivation device is necessary sometimes in order to satisfy the criteria.%介绍了电炉炼钢烟气中二(口恶)英的产生机理,特别介绍其废钢预热系统将使其烟气中二(口恶)英浓度显著增加的成因,提出了带废钢预热的电炉炼钢时,应充分考虑采取废钢的分选净化、烟气有效收集和采用除脱设备等措施,特别是采用控制预热后烟气温度、喷石灰、加快余热锅炉冷却速度等合理的工艺及技术,以抑制电炉炼钢烟气中二(口恶)英的持续生成.

  4. An Experimental Study on High Temperature and Low Oxygen Air Combustion

    Institute of Scientific and Technical Information of China (English)

    W.B.Kim; D.H.Chung; 等

    2000-01-01

    High temperature preheated and diluted air combustion has been confirmed as the technolgy,mainly applied to industrial furnaces and kilns,to realize higher thermal efficiency and lower emissions.The purpose of this study was to investigate fundamental aspects of the above-mentioned combustion experimentally and to compare with those in ordinary hydrocarbon combustion with room temperature air.The test items were exhaust gas components of CO,NOx,flame shape and raidcal components of CH,OH and C2,which were measured with gas analyser,camera and ICCD(Intersified Charged-Coupled Device) camera.Many phenomena as results appeared in combustion with the oxidizer,low oxygen concentation and extremely high temperature air,such as expansion of the flammable limits,increased flame propagation speed,it looked so strange as compared with those in existing combustion technology,we confirmed that such extraordinary phenomena were believable through the hot-test experiment.

  5. Direct numerical simulation of stationary lean premixed methane-air flames under intense turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Sankaran, Ramanan [ORNL; Hawkes, Evatt R [Sandia National Laboratories (SNL); Yoo, Chun S [Sandia National Laboratories (SNL); Chen, Jacqueline H [Sandia National Laboratories (SNL); Lu, Tianfeng [Princeton University; Law, Chung K [Princeton University

    2007-01-01

    Direct numerical simulation of a three-dimensional spatially- developing turbulent Bunsen flame has been performed at three different turbulence intensities. The simulations are performed using a reduced methane-air chemical mechanism which is specifically tailored for the lean premixed conditions simulated here. A planar-jet turbulent Bunsen flame configuration is used in which turbulent preheated methane-air mixture at 0.7 equivalence ratio issues through a central jet and is surrounded by a hot laminar coflow of burned products. The turbulence characteristics at the jet inflow are selected such that combustion occurs in the thin reaction zones (TRZ) regime. At the lowest turbulence intensity the conditions fall on the boundary between the TRZ regime and the corrugated flamelet regime. At the highest turbulence intensity the conditions correspond to the boundary between the TRZ regime and the broken reaction zones regime. The data from the three simulations is analyzed to understand the effect of turbulent stirring on the flame structure and thickness. Statistical analysis of the data shows that the thermal preheat layer of the flame is thickened due to the action of turbulence, but the reaction zone is not significantly affected.

  6. Explore the Energy-saving Effect of Decomposition Kiln System with Four-stage, Five-stage and Six-stage Preheater%四级、五级和六级预热预分解窑系统节能效果的探讨

    Institute of Scientific and Technical Information of China (English)

    李红建; 王国鸿; 周刘成; 李昌勇

    2013-01-01

    通过四级、五级和六级预热预分解窑系统节约煤电的比较,阐明了带余热发电的五级预热预分解窑系统的能源利用率高于带余热发电的四级预热预分解窑系统,而六级预热器系统比五级、四级预热器系统节能效果更好.采用六级预热器系统可以适当降低预热器出口废气温度,实现废气热焓的充分回收,从而有效地实现烧成系统的节能减排.%By contrasting energy-saving of decomposition kiln system with four-stage, five-stage and six-stage preheater, it clarified that energy efficiency of system with five-stage preheater and waste heat power generation was higher than system with four-stage preheater. The energy-saving effect of six-stage preheater is better than five-stage and four-stage preheater. Six-stage preheater system was appropriate to reduce the outlet exhaust gas temperature of the preheater, while the exhaust gas enthalpy could be fully recycled,which easily achieved the purpose of the energy-saving and emissions reduction of the firing system.

  7. Produced Fluid Treatment at SAGD Steam Circulation Preheating Stage in Fengcheng Oilfield%风城油田SAGD循环预热采出液处理技术

    Institute of Scientific and Technical Information of China (English)

    霍进; 陈贤; 桑林翔; 陈弘毅; 李学军

    2016-01-01

    Conventional oil demulsifier is ineffective for produced fluid at SAGD steam cir-culation preheating stage in Fengcheng oilfield. The produced fluid flowing into oil process plant leads to water- cut increasing in crude oil and sewage treatment difficulty. With the wide application of SAGD technique in super heavy oil exploitation, produced fluid treat-ment becomes a critical problem to be resolved. The stabilization mechanism of produced fluid was investigated by physical properties analysis,micrographic determination and zeta po-tential measurement, and the colloidal dispersion character of produced fluid was recognized. Based on high efficient treatment agents and process optimization, produced fluid oil- water separation, floating oil dehydration and sewage purification were realized. The process tech-nique that vapor- liquid separation, spraying cooling, oil- water separation, and floating oil recovery for produced fluid treatment was formed, which is an important technical guar-antee for SAGD development and a good reference for similar reservoir development.%在风城油田SAGD循环预热采出液处理中使用常规破乳药剂无法实现油水分离,采出液进入稠油处理站后,易造成净化原油含水升高、脱出污水净化困难.随着超稠油SAGD开发规模的不断扩大,亟待解决循环预热采出液的处理难题.通过物性分析、显微照相和Zeta电位测定等手段研究了循环预热采出液的稳定机理以及循环预热采出液的胶体分散特性,并研制出复合净水药剂进行破胶,结合工艺优化实现了循环预热采出液的油水分离、浮油脱水和污水净化,形成了"汽液分离+喷淋降温+油水分离+浮油回收"的循环预热采出液处理工艺技术.该技术为SAGD规模开发提供了技术保障,为同类油藏的开发提供了借鉴.

  8. Air Pollution

    Science.gov (United States)

    ... to view this content or go to source URL . What NIEHS is Doing on Air Pollution Who ... Junction Last Reviewed: February 06, 2017 This page URL: NIEHS website: https://www.niehs.nih.gov/ Email ...

  9. Computational Fluid Dynamic Modeling of Horizontal Air-Ground Heat Exchangers (HAGHE for HVAC Systems

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2014-12-01

    Full Text Available In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB, innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe.

  10. Air surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  11. Preheating of coal. Its influence on the composition of coal, the quality of coke and on the phenomenon of pushing. Precalentado del carbon. Su influencia en la composicion del carbon, en la calidad del coque y en el fenomeno del empuje

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    A comparative study of the carbonization of a wide range of coals, wet and after preheating, was carried out. The 6 t coal capacity oven of the INCAR Experimental Coking Test Plant and the 2 t/h preheating pilot plant, Precarbon process, installed by ENSIDESA annexed to the INCAR plant were used. Influence of the preheating process on coal plastic properties was followed through Arnu dilatation, Gieseler fluidity and swelling index tests. Structural modifications of the coals were examined by FT-IR. Coal samples [lt]0.15 mm that do not need to be crushed for analysis and Arnu dilatation were chosen. A Koppers-INCAR test of all coals studied was carried out. Cokes obtained were characterized by optical microscopy, SEM and image analysis. Size analysis, coke strength (Micum e Irsid tests), reactivity and post-reaction strength, chemical changes and porosity were also determined. 21 refs., 36 figs., 9 tabs.

  12. Royal Danish Air Force. Air Operations Doctrine

    DEFF Research Database (Denmark)

    Nørby, Søren

    This brief examines the development of the first Danish Air Force Air Operations Doctrine, which was officially commissioned in October 1997 and remained in effect until 2010. The development of a Danish air power doctrine was heavily influenced by the work of Colonel John Warden (USAF), both...... through his book ”The Air Campaign” and his subsequent planning of the air campaign against Iraq in 1990-1991. Warden’s ideas came to Denmark and the Danish Air Force by way of Danish Air Force students attending the United States Air Force Air University in Alabama, USA. Back in Denmark, graduates from...... the Air University inspired a small number of passionate airmen, who then wrote the Danish Air Operations Doctrine. The process was supported by the Air Force Tactical Command, which found that the work dovetailed perfectly with the transformation process that the Danish Air Force was in the midst...

  13. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devices The Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  14. Air-to-Air Missile Vector Scoring

    Science.gov (United States)

    2012-03-22

    64 4.6. Unscented Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get...Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Executing a Vertical Climb...Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Non-maneuvering

  15. Modelling and experimental validation of the hot-gas defrost process of an air-cooled evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Dopazo, J. Alberto; Fernandez-Seara, Jose; Uhia, Francisco J.; Diz, Ruben [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No 9, 36310 Vigo, Pontevedra (Spain)

    2010-06-15

    A detailed transient simulation model has been developed to predict and evaluate the performance of the hot-gas defrost process of an air-coil evaporator. In the model, the defrost process is subdivided into six stages: preheating, tube frost melting start, fin frost melting start, air presence, tube-fin water film and dry-heating. In each stage, the control volume is subdivided into systems represented by a single node, which has the representative properties of the system. A finite difference approach was used to solve the model equations. The results include the time required to defrost, the distribution of the energy during defrost process, the instantaneous refrigerant properties and the instantaneous fin and tube temperature distribution. The results are compared with experimental data obtained in a local storage facility under actual operating conditions and also using data available in the literature. The model results substantially agree with the experimental data in both cases. (author)

  16. R9 Air Districts

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 9 Air Districts layer is a compilation of polygons representing the California Air Pollution Control and Air Quality Management Districts, Arizona Air...

  17. AirData

    Data.gov (United States)

    U.S. Environmental Protection Agency — The AirData site provides access to yearly summaries of United States air pollution data, taken from EPA's air pollution databases. AirData has information about...

  18. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  19. Effect of pre-heat treatments and cold rolling reduction on recrystallization texture of 6082 aluminum alloy%预处理和变形量对6082铝合金再结晶织构的影响

    Institute of Scientific and Technical Information of China (English)

    江海涛; 孙璐; 蔡正旭; 张成刚

    2013-01-01

    采用取向分布函数法分析并研究了冷轧前预处理和冷轧变形量对6082铝合金再结晶的影响.结果表明,6082铝合金的再结晶织构主要由立方织构和旋转立方织构组成.不经过热处理和经过固溶时效处理的试样,随着冷轧变形量的增加,再结晶织构组分明显增加;只经过固溶处理的试样,随着冷轧变形量的增加,再结晶织构组分变化不明显,说明冷轧前固溶处理可以明显弱化再结晶织构.%Effects of pre-heat treatments and cold rolling reduction on recrystallization texture of 6082 aluminum alloy were investigated by ODF (orientation distribution function).The results show that the recrystallization textures of 6082 aluminum alloy consist of cube texture and rotated cube texture components.For the samples without pre-heat treatment and overaging treatment,the recrystallization textures obviously increase with the increasing cold rolling reduction.However,the recrystallization textures change little with the increasing of cold rolling reduction for the solution-treated samples.The process of solution treatment before cold rolling can weaken the recrystallization texture of 6082 aluminum alloy.

  20. Numerical Study of Air Nozzles on Mild Combustion for Application to Forward Flow Furnace

    Institute of Scientific and Technical Information of China (English)

    Liu Bo; Wang Yuanhua; Xu Hong

    2016-01-01

    An attempt was made to extend mild combustion to forward lfow furnace, such as the reifnery and petrochemical tube furnace. Three dimensional numerical simulation was carried out to study the performance of this furnace. The Eddy Dissipation Concept (EDC) model coupled with the reaction mechanism DRM-19 was used. The prediction showed a good agreement with the measurement. The effect of air nozzle circle (D), air nozzle diameter (d), air nozzle number (N), and air preheating temperature (Tair) on the lfow, temperature and species ifelds, and the CO and NO emissions was investigated. The results indicate that there are four zones in the furnace, viz.:a central jet zone, an ignition zone, a combustion reaction zone, and a lfue gas zone, according to the distribution proifles of H2CO and OH. The central jet entrains more lfue gas in the furnace upstream with an increasing D while the effect of D is negligible in the downstream. The air jet momentum increases with a decreasing d or an increasing Tair, and entrains more lfue gas. The effect of N is mainly identiifed near the burner exit. More heat is absorbed in the radiant section and less heat is discharged to the atmosphere with a decreasing d and an increasing N as evidenced by the lfue gas temperature. The CO and NO emissions are less than 50μL/L and 10μL/L, respectively, in most of conditions.

  1. Air Warfare

    Science.gov (United States)

    2002-03-01

    undoubtedly begat the shield; poisonous gases were countered by the mask. Surely men on the surface of the earth will not have to submit to violent air attack...properties, production methods and cost of helium are given in “Balloon and Airship Gases ,” a volume of the Ronald Aeronautic Library. 5 More complete...becomes and more inse - cure. We shall see later that even some of the men who were advancing in the path prescribed by the principle of mass

  2. Op timized Operation of and Structural Improvement on Large Heat-Pige Air Preheater%大型热管空气预热器的优化运行与构造改进

    Institute of Scientific and Technical Information of China (English)

    王民杰

    2002-01-01

    扼要介绍了热管空气预热器的运行状况,对其不足进行了总结,提出需确保进入热管空气预热器的烟气温度小于300℃、热管中部封头的密封改进、加大部分热管的翅片间距、改进翅片与管的连接方式及部分使用纵向翅片热管等措施.

  3. 可调频高声强声波吹灰器在600MW机组空预器中的应用%Application of high intensity sonic soot blower in air preheater of 600 MW units

    Institute of Scientific and Technical Information of China (English)

    尤良洲

    2016-01-01

    通过现场试验结合DCS数据分析,评估可调频高声强声波吹灰器在桌600MW机组空预器上的应用.结果表明,可调频高声强声波吹灰器可在氨逃逸波动较大的情况下,有效控制空预器阻力的增长,保证机组运行.

  4. Analysis on the SCR Catalyst Activity Reducing the Effects of Corrosion to the Air Preheater%SCR催化剂活性降低对空预器腐蚀的影响分析

    Institute of Scientific and Technical Information of China (English)

    于洪海; 陈利; 曲立涛

    2016-01-01

    SCR催化剂是SCR烟气脱硝工艺的关键,SCR催化剂活性降低将会对空预器造成腐蚀影响,通过某燃煤电厂300MW机组实例,分析了SCR催化剂活性降低造成空预器腐蚀的原因,并给出了在实际运行中减轻SCR催化剂活性降低对空预器腐蚀影响的建议.

  5. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air....... These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  6. Air pollution

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-01

    Air pollution conditions in Iwakuni city were monitored at 9 monitoring stations, and 21 locations where sulfur oxides were measured by the lead peroxide candle method, and 13 locations where particulates concentrations were determined by the deposit cage method. The average SO/sub x/ concentrations in 1973 measured by the lead peroxide candle method ranged from 0.17 mg sulfur trioxide/day/100 sq cm at the Miso Office to 0.58 mg SO/sub 3//day/100 sq cm at Mitsui Sekiyu Shataku. The average SO/sub x/ concentrations measured by the conductivity method ranged from 0.021 ppM at Kazuki Kominkan to 0.037 ppM at the Higashi Fire Department. Only 58% of a total of 264 measurement days gave hourly average concentrations below the environmental standard of 0.04 ppM at the Higashi Fire Deparment. The average airborne particulate concentrations ranged from 0.050 mg/cu m at Totsu Kominkan to 0.056 mg/cu at the Higashi Fire Department. The average nitrogen oxides concentrations measured by the Saltzman method ranged from 0.007 ppM to 0.061 ppM. The average oxidant concentrations at the Iwakuni Municipal Office and Kazuki Kominkan were 0.028 ppM and 0.037 ppM, respectively.

  7. Effects of pin angle and preheating on temperature distribution during friction stir welding operation%搅拌摩擦焊接过程中搅拌针锥角和预热对温度分布的影响

    Institute of Scientific and Technical Information of China (English)

    R. KEIVANI; B. BAGHERI; F. SHARIFI; M. KETABCHI; M. ABBASI

    2013-01-01

    Friction stir welding (FSW) is applied extensively in industry for joining of nonferrous metals especially aluminum. A three-dimensional model based on finite element analysis was used to study the thermal characteristic of copper C11000 during the FSW process. The model incorporates the mechanical reaction of the tool and thermo-mechanical characteristics of the weld material, while the friction between the material and the probe and the shoulder serves as the heat source. It was observed that the predicted results about the temperature were in good compatibility with the experimental results. Additionally, it was concluded that the numerical method can be simply applied to measuring the temperature of workpiece just beneath the tool. The effects of preheating temperature and pin angle on temperature distribution were also studied numerically. The increase of pin angle enhances the temperature around the weld line, but preheating does not affect temperature distribution along the weld line considerably.%搅拌摩擦焊(FSW)被广泛应用在工业上,用来连接有色金属,尤其是铝合金。采用基于有限元分析的三维模型研究FSW过程中铜C11000的热特性。模型包含了搅拌头的机械作用和待焊接材料的热性能,以材料和搅拌针以及轴肩之间的摩擦作为热源。结果表明,温度的预测结果与实验结果具有良好的一致性。此外,数值模拟方法可以简单地应用于测量搅拌头下方工件的温度。研究了预热温度和搅拌针锥角对温度分布的影响。搅拌针锥角的增加可提高焊缝周围的温度,但预热不会影响焊缝周围的温度分布。

  8. Air Sensor Toolbox

    Science.gov (United States)

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  9. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  10. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  11. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... States Environmental Protection Agency Search Search Lead (Pb) Air Pollution Share Facebook Twitter Google+ Pinterest Contact Us As ... and protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Lead Air Pollution Basics How does lead get ...

  12. AirPEx: Air Pollution Exposure Model

    OpenAIRE

    Freijer JI; Bloemen HJTh; de Loos S; Marra M; Rombout PJA; Steentjes GM; Veen MP van; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants. T...

  13. Experimental investigation of wood combustion in a fixed bed with hot air

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, Miladin, E-mail: m.markovic@utwente.nl; Bramer, Eddy A.; Brem, Gerrit

    2014-01-15

    Highlights: • Upward combustion is a new combustion concept with ignition by hot primary air. • Upward combustion has three stages: short drying, rapid devolatilization and char combustion. • Variation of fuel moisture and inert content have little influence on the combustion. • Experimental comparison between conventional and upward combustion is presented. - Abstract: Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of

  14. AirPEx: Air Pollution Exposure Model

    NARCIS (Netherlands)

    Freijer JI; Bloemen HJTh; Loos S de; Marra M; Rombout PJA; Steentjes GM; Veen MP van; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The

  15. Air Pollution Monitoring | Air Quality Planning & Standards ...

    Science.gov (United States)

    2016-06-08

    The basic mission of the Office of Air Quality Planning and Standards is to preserve and improve the quality of our nation's air. To accomplish this, OAQPS must be able to evaluate the status of the atmosphere as compared to clean air standards and historical information.

  16. REACH. Air Conditioning Units.

    Science.gov (United States)

    Garrison, Joe; And Others

    As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of air conditioning. The instructional units focus on air conditioning fundamentals, window air conditioning, system and installation, troubleshooting and…

  17. Statistical air quality mapping

    NARCIS (Netherlands)

    Kassteele, van de J.

    2006-01-01

    This thesis handles statistical mapping of air quality data. Policy makers require more and more detailed air quality information to take measures to improve air quality. Besides, researchers need detailed air quality information to assess health effects. Accurate and spatially highly resolved maps

  18. Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

    Science.gov (United States)

    Guangul, F. M.; Sulaiman, S. A.; Ramli, A.

    2013-06-01

    Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

  19. Air movement and perceived air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2012-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative...... and the humidity of the room air. At a low humidity level of 30% an increased velocity could compensate for the decrease in perceived air quality due to an elevated temperature ranging from 20 °C to 26 °C. In a room with 26 °C, increased air movement was also able to compensate for an increase in humidity from 30...

  20. Performance testing of an air/water heat pump using CO{sub 2} (R744) as refrigerant for the preparation of sanitary hot water in a hospital; Mesures des donnees energetiques d'une pompe a chaleur air/eau au CO{sub 2} (R744) pour preparation d'eau chaude sanitaire dans un hopital

    Energy Technology Data Exchange (ETDEWEB)

    Anstett, P.

    2006-07-01

    This final report prepared for the Swiss Federal Office of Energy (SFOE) describes the monitoring equipment and the results of performance tests made on a prototype heat pump of 60 kW power output used for hot water production at the hospital of Le Locle, Switzerland. The heat pump uses carbon dioxide (R744) as the working fluid and ambient air as the heat source. The heat output and the coefficient of performance for various values of cold water temperature and air temperature have been measured. The practically measured values of heat output and COP showed a low reproducibility and remained far behind the theoretical values given by the manufacturer. Instead of producing hot water at 80 {sup o}C as intended originally the authors recommend to use the heat pump only for preheating the water to 60 {sup o}C.

  1. Microstructure and property of 65Mn steel preheated by laser strengthening%农机用65Mn钢预热处理后激光强化组织及性能

    Institute of Scientific and Technical Information of China (English)

    黄永俊; 张国忠

    2015-01-01

    针对农机刀具易于磨损,且强化处理工艺较复杂、成本较高的现状,在正火和淬火-中温回火预热处理65Mn钢上,分别进行激光淬火和激光熔凝加工,研究了激光加工后的组织结构及显微硬度的变化规律,并探讨了其影响因素。研究结果表明:激光强化组织由表层熔凝区(激光熔凝)、完全淬火区、不完全淬火区、热影响区组成;正火预热处理后激光强化组织的显微硬度要高于淬火-中温回火预热处理后激光强化组织的显微硬度,激光熔凝处理后硬化区的显微硬度稍低于激光淬火硬化区的显微硬度。该研究为激光强化农机刀具的组织改善和性能提高提供了依据。%At present, there exists a problem that the agricultural tools easily get worn. However, the common strengthening techniques have visible disadvantages, such as the complex process and comparatively high running cost. In order to solve the problem, the 65Mn steel was preheat-treated by the normalization or quenching + medium-temperature tempering. Subsequently, the preheat-treated 65Mn steel was strengthened by laser quenching or laser melting-hardening process with a YLR-6000 fiber laser. The microstructure was studied by optical microscope and scanning electronic microscope. The microhardness was measured using a Vickers-1000 microhardness tester with load of 1.96N and a dwelling time of 15s. Further, the controlling factors were investigated. The results showed that the preheat-treating and laser process had visible influences on the microstructure and property. In laser quenching, the microstructure was comprised of the entire quenching zone, part quenching zone and heat affected zone. The fine needle martensite was obtained in entire quenching zone by quenching + medium-temperature tempering + laser quenching. In the part quenching zone, the microstructures were fine needle martensite and troolstite. However, the fine needle

  2. AirCompare

    Data.gov (United States)

    U.S. Environmental Protection Agency — AirCompare contains air quality information that allows a user to compare conditions in different localities over time and compare conditions in the same location...

  3. Allegheny County Air Quality

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Air quality data from Allegheny County Health Department monitors throughout the county. Air quality monitored data must be verified by qualified individuals before...

  4. Air Quality Facilities

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Facilities with operating permits for Title V of the Federal Clean Air Act, as well as facilities required to submit an air emissions inventory, and other facilities...

  5. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  6. Air Quality System (AQS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements...

  7. Air Power and Warfare

    Science.gov (United States)

    1978-09-01

    Memorial, 1963. (T) 767.8 A3 ser .3, V.4) Air war against Germany and Italy, 1939-1943. Canberra: Australian War Memorial, 1954. (D 767.8 A3 Ser .3, V.3...et al. Air poder indivisible Air University Ouarterly Review 2:5-18, Fall 1950. Spaatz, Crrl. Air-power odds against us. Readers Digest 58:11-14, June

  8. Indoor air quality

    DEFF Research Database (Denmark)

    Jensen, Trine Susanne; Recevska, Ieva

     The objective of the 35th specific agreement is to provide support to the EEA activities in Environment and Health (E&H) on the topic of indoor air quality. The specific objectives have been to provide an overview of indoor air related projects in EU and indoor air related policies as well...... as idenfiying "good practices" to reduce health impact of indoor air exposure and suggest areas for future improvements....

  9. We Pollute the Air

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    1.Clean air is important to good health.If the aircontains impurities,they may be absorbed by ourbodies and make us ill.We need clean air,butunfortunately,air pollution is generally present,especially in cities. 2.Our cities have many factories,which we need tomake food products,clothing and many other things.

  10. Air Pollution Training Programs.

    Science.gov (United States)

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  11. Manual for THOR-AirPAS - air pollution assessment system

    DEFF Research Database (Denmark)

    Jensen, Steen Solvang; Ketzel, Matthias; Brandt, Jørgen

    The report provides an outline of the THOR-AirPAS - air pollution assessment system and a brief manual for getting started with the air quality models and input data included in THOR-AirPAS.......The report provides an outline of the THOR-AirPAS - air pollution assessment system and a brief manual for getting started with the air quality models and input data included in THOR-AirPAS....

  12. Air Conditioning Does Reduce Air Pollution Indoors

    Science.gov (United States)

    Healy, Bud

    1970-01-01

    Report of the winter meeting of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Subjects covered are--(1) title subject, (2) predictions for the human habitat in 1994, (3) fans, and (4) fire safety in buildings. (JW)

  13. 46 CFR 56.85-10 - Preheating.

    Science.gov (United States)

    2010-10-01

    ... thickness in inches for thickness over 2 inches. (10) Heating route for induction heating must not exceed.... (9) Heating rate for furnace, gas, electric resistance, and other surface heating methods must not.... (11) When local heating is used, the weld must be allowed to cool slowly from the postheat...

  14. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  15. Effect of pre-heat treatment on mechanical properties of high-strength stainless steel 00Cr12Ni10MoTi for cryogenic applications%预处理对低温用高强度钢00Cr12Ni10MoTi力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    葛鹏; 杨卓越; 丁雅莉

    2013-01-01

    研究了预处理对低温用高强度不锈钢00Cr12Ni10MoTi力学性能的影响.结果表明,经过750℃预处理和750℃最终固溶处理后发生两次非扩散α’→γ相变,此时奥氏体经过两次相变硬化,位错密度明显提高,强度显著增加,同时预处理形成了稳定的马氏体/奥氏体复相组织改善了低温韧性;预处理温度低于750℃、尤其是低于As点会使750℃固溶处理的最终残留奥氏体逆转变量显著增加,低温韧性进一步提高,但钢的强度明显降低.%The effect of pre-heat treatment on the mechanical properties of high-strength stainless steel 00Cr12Ni10MoTi for cryogenic application was studied.The results show that the defect density of phase strained-hardened austenite is increased largely by undergoing nondiffusion reverse α'→γ transformation twice after pre-heat treat treatment at 750 ℃ and finally solution treatment and that the strength is improved.And the stable martensite-austenite structure ensuring high toughness at low temperature is acquired through the pre-heat treatment.As the temperature of pre-heat treatment decreased to lower than 750 ℃,especially to below As point,more retained/reversed austenite is formed.It resultes in a low strength although the presence of austenite produces the most favorable effect on the increase in the impact toughness at cryogenic temperatures.

  16. Air/ground heat exchanger (GHE): Modelling, design, performance; Luft-/Erdwaermetauscher EWT: Modellierung, Auslegung und Betriebserfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, A. [Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg (Germany); Pfafferott, J. [Energieversorgung Spree-Schwarze Elster AG (ESSAG), Cottbus (Germany); Dibowski, G. [Deutsches Zentrum fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Abt. Sonnenofen

    1998-02-01

    Air/Ground Heat Exchanger (GHE) utilize soil for seasonal heat storage and are used for air preheating or -cooling. Design and layout require suitable tools which adequately describe the complex heat temperature mechanisms in soils. Since heat densities in soil and heat exchange coefficients between air and GHE are both low, a detailed characterization of the soil and a precise modeling of the heat exchange processes within the GHE are needed. Tools for the design and yield prediction of GHE are presented by way of examples. Results are compared with measured data and both opportunities and limitations of GHEs are discussed using calculated and actual data. (orig.) [Deutsch] Luft-/Erdwaermetauscher EWT nutzen das Erdreich als saisonalen Energiespeicher, sie werden beispielsweise zur Zuluft-Vorerwaermung oder -kuehlung eingesetzt. Die Planung und Auslegung von Luft-/Erdwaermetauschern erfordert geeignete Hilfsmittel, um das komplizierte Temperaturfeld im Erdreich mit ausreichender Genauigkeit abbilden zu koennen. Da die Waermestromdichten im Erdreich und der Waermeuebergang zwischen der Luft im Luft-/Erdwaermetauscher und dem umgebenden Erdreich gering sind, ist sowohl eine detaillierte Abbildung des Erdreichs als auch die Modellierung des Waermeuebergangs im Luft-/Erdwaermetauscher erforderlich. Verfahren zur Auslegung und Ertragsvorhersage von Luft-/Erdwaermetauschern werden vorgestellt und deren Anwendung demonstriert. Die Ergebnisse werden mit Betriebserfahrungen von realisierten Luft-/Erdwrmetauschern verglichen. Moeglichkeiten und Grenzen von Luft-/Erdwaermetauschern werden anhand von Praxis und Simulationsrechnungen diskutiert. (orig.)

  17. 走近Air

    Institute of Scientific and Technical Information of China (English)

    马华

    2007-01-01

    @@ 大家对air这个单词并不陌生,它通常用作名词,表示"空气".例如: 1.Better let in fresh air. 最好让新鲜空气进来. 2.The air smells of paint. 空气里散发着油漆味. 3.The air was heavy with perfume of the flowers. 空气里弥漫着花朵的芳香.

  18. Contact air abrasion.

    Science.gov (United States)

    Porth, R

    1999-05-01

    The advantages of contact air abrasion techniques are readily apparent. The first, of course, is the greatly increased ease of use. Working with contact also tends to speed the learning curve by giving the process a more natural dental feel. In addition, as one becomes familiar with working with a dust stream, the potential for misdirecting the air flow is decreased. The future use of air abrasion for deep decay removal will make this the treatment of choice for the next millennium.

  19. Olefin metathesis in air.

    Science.gov (United States)

    Piola, Lorenzo; Nahra, Fady; Nolan, Steven P

    2015-01-01

    Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  20. AIR RADIOACTIVITY MONITOR

    Science.gov (United States)

    Bradshaw, R.L.; Thomas, J.W.

    1961-04-11

    The monitor is designed to minimize undesirable background buildup. It consists of an elongated column containing peripheral electrodes in a central portion of the column, and conduits directing an axial flow of radioactively contaminated air through the center of the column and pure air through the annular portion of the column about the electrodes. (AEC)

  1. Air-Conditioning Mechanic.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by air conditioning mechanics. Addressed in the four chapters, or lessons, of the manual are the following topics: principles of air conditioning, refrigeration components as…

  2. The Air We Breathe

    Science.gov (United States)

    Davila, Dina

    2010-01-01

    Topics discussed include NASA mission to pioneer the future in space exploration, scientific discovery and aeronautics research; the role of Earth's atmosphere, atmospheric gases, layers of the Earth's atmosphere, ozone layer, air pollution, effects of air pollution on people, the Greenhouse Effect, and breathing on the International Space Station.

  3. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...

  4. Bad Air For Children

    Science.gov (United States)

    Kane, Dorothy Noyes

    1976-01-01

    Children are especially sensitive to air pollution and consequences to them maybe of longer duration than to adults. The effects of low-level pollution on children are the concern of this article. The need for research on the threat of air pollution to childrens' health is emphasized. (BT)

  5. Air pollution and society

    OpenAIRE

    Brimblecombe P.

    2010-01-01

    Air pollution is as much a product of our society as it is one of chemistry and meteorology. Social variables such as gender, age, health status and poverty are often linked with our exposure to air pollutants. Pollution can also affect our behaviour, while regulations to improve the environment can often challenge of freedom.

  6. Over the air test

    DEFF Research Database (Denmark)

    2015-01-01

    [1] This invention relates to over-the-air testing of a device in an anechoic chamber. In particular, the invention is suitable for simulating both uplink and downlink over-the-air communication with a device under test even when the anechoic chamber has different numbers of uplink and downlink...

  7. Air Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; O'Donnell, Patrick A.

    One of three in a series about pollution, this teacher's guide for a unit on air pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of air pollution and involves students in processes of…

  8. Air Pollution and Industry.

    Science.gov (United States)

    Ross, R. D., Ed.

    This book is an authoritative reference and practical guide designed to help the plant engineer identify and solve industrial air pollution problems in order to be able to meet current air pollution regulations. Prepared under the editorial supervision of an experienced chemical engineer, with each chapter contributed by an expert in his field,…

  9. Bearings Only Air-to-Air Ranging

    Science.gov (United States)

    1988-07-25

    sensor, observer and target parameters still remain. In order to reduce the number of cases to a manageable one, while preserving the geometric...perforance of variotu. ulro-air passive ranging tecnique has been examined as a fimn- tiam of uarget location andi motiom, observer motion. and length

  10. Restoran Buenos Aires = Restaurant Buenos Aires

    Index Scriptorium Estoniae

    2008-01-01

    Restorani Buenos Aires (Narva mnt. 5, Tallinn) sisekujundusest. Sisearhitektid: Janno Roos ja Andres Labi (Ruumilabor OÜ). Laudu eraldavad 400 vardasse aetud puukuuli. Sisearhitektidest, nende tähtsamad tööd. I-III korruse plaan, 12 värv. vaadet, fotod sisearhitektidest

  11. AIRE-Linux

    Science.gov (United States)

    Zhou, Jianfeng; Xu, Benda; Peng, Chuan; Yang, Yang; Huo, Zhuoxi

    2015-08-01

    AIRE-Linux is a dedicated Linux system for astronomers. Modern astronomy faces two big challenges: massive observed raw data which covers the whole electromagnetic spectrum, and overmuch professional data processing skill which exceeds personal or even a small team's abilities. AIRE-Linux, which is a specially designed Linux and will be distributed to users by Virtual Machine (VM) images in Open Virtualization Format (OVF), is to help astronomers confront the challenges. Most astronomical software packages, such as IRAF, MIDAS, CASA, Heasoft etc., will be integrated into AIRE-Linux. It is easy for astronomers to configure and customize the system and use what they just need. When incorporated into cloud computing platforms, AIRE-Linux will be able to handle data intensive and computing consuming tasks for astronomers. Currently, a Beta version of AIRE-Linux is ready for download and testing.

  12. Airing 'clean air' in Clean India Mission.

    Science.gov (United States)

    Banerjee, T; Kumar, M; Mall, R K; Singh, R S

    2016-12-30

    The submission explores the possibility of a policy revision for considering clean air quality in recently launched nationwide campaign, Clean India Mission (CIM). Despite of several efforts for improving availability of clean household energy and sanitation facilities, situation remain still depressing as almost half of global population lacks access to clean energy and proper sanitation. Globally, at least 2.5 billion people do not have access to basic sanitation facilities. There are also evidences of 7 million premature deaths by air pollution in year 2012. The situation is even more disastrous for India especially in rural areas. Although, India has reasonably progressed in developing sanitary facilities and disseminating clean fuel to its urban households, the situation in rural areas is still miserable and needs to be reviewed. Several policy interventions and campaigns were made to improve the scenario but outcomes were remarkably poor. Indian census revealed a mere 31% sanitation coverage (in 2011) compared to 22% in 2001 while 60% of population (700 million) still use solid biofuels and traditional cook stoves for household cooking. Further, last decade (2001-2011) witnessed the progress decelerating down with rural households without sanitation facilities increased by 8.3 million while minimum progress has been made in conversion of conventional to modern fuels. To revamp the sanitation coverage, an overambitious nationwide campaign CIM was initiated in 2014 and present submission explores the possibility of including 'clean air' considerations within it. The article draws evidence from literatures on scenarios of rural sanitation, energy practises, pollution induced mortality and climatic impacts of air pollution. This subsequently hypothesised with possible modification in available technologies, dissemination modes, financing and implementation for integration of CIM with 'clean air' so that access to both sanitation and clean household energy may be

  13. Location Problem of Air Materials Supply Center for Air Force

    Institute of Scientific and Technical Information of China (English)

    王涛; 何亚群; 陶学禹

    2002-01-01

    Based on the analysis of three influencing factors on the air material supply center location, the location model of air material supply center was established. By solving the model, the rational supply center of air materials was also determined.

  14. Air Baltic: Estonian Air on nurka surutud / Teele Tammeorg

    Index Scriptorium Estoniae

    Tammeorg, Teele

    2010-01-01

    Air Balticu asepresidendi Janis Vanagsi hinnangul on Estonian Air aastaid jätnud tähelepanuta oma peamised turismiturud ning on praegu halvas seisus. Air Baltic on endiselt huvitatud Estonian Airi ostust. Majandus- ja kommunikatsiooniminister Juhan Partsi seisukoht

  15. Performance of a diesel engine fueled with a preheated blend of soybean oil and petrodiesel Desempenho de um motor diesel alimentado com uma mistura pré-aquecida de óleo de soja e petrodiesel

    Directory of Open Access Journals (Sweden)

    Hevandro C. Delalibera

    2012-12-01

    Full Text Available Brazil is doing a major effort to find alternatives to diesel oil as combustible. Some study lines are oriented to the development of vegetable oils used as fuel, as a source of getting cheaper and have higher energy density than the converted vegetable oils, and less risk of environmental contamination. The aim of this study was to evaluate the performance, the useful life of the lubricant and some components of a Diesel Cycle engine, with an electronic injection system, in a long-term test operating with a preheated blend (65°C of 50% (v v-1 of soybean oil in petrodiesel. There was a reduction of the useful life of the injectors which presented failure because of high wear with 264 hours of operation and showed an increase in emissions of particulate matter (opacity which may be assigned to the failures occurred in the injection system. An increase in the useful life of the lubricant, when compared with the literature was also observed. The electronic injection system may favor the burning of the tested fuel. The test was interrupted with 264 hours because of failures in the injection system.No Brasil, tem-se notado um grande esforço para encontrar alternativas ao óleo diesel como combustível. Algumas linhas de estudo estão direcionadas ao desenvolvimento dos óleos vegetais para tal fim, por ser uma fonte de obtenção de menor custo e ter densidade energética maior que os óleos vegetais transformados, além de apresentar menor risco de contaminação ambiental. O objetivo deste trabalho foi avaliar o desempenho, a vida útil do lubrificante e de alguns componentes de um motor Ciclo Diesel, com sistema de injeção eletrônica, em um ensaio de longa duração, sendo este alimentado com uma mistura pré-aquecida (65 °C de 50% (v v-1 de óleo de soja no petrodiesel. Observou-se redução da vida útil dos injetores que apresentaram falha por desgaste elevado com 264 h de funcionamento e aumento da emissão de material particulado

  16. Air Cleaning Technologies

    Science.gov (United States)

    2005-01-01

    Executive Summary Objective This health technology policy assessment will answer the following questions: When should in-room air cleaners be used? How effective are in-room air cleaners? Are in-room air cleaners that use combined HEPA and UVGI air cleaning technology more effective than those that use HEPA filtration alone? What is the Plasmacluster ion air purifier in the pandemic influenza preparation plan? The experience of severe acute respiratory syndrome (SARS) locally, nationally, and internationally underscored the importance of administrative, environmental, and personal protective infection control measures in health care facilities. In the aftermath of the SARS crisis, there was a need for a clearer understanding of Ontario’s capacity to manage suspected or confirmed cases of airborne infectious diseases. In so doing, the Walker Commission thought that more attention should be paid to the potential use of new technologies such as in-room air cleaning units. It recommended that the Medical Advisory Secretariat of the Ontario Ministry of Health and Long-Term Care evaluate the appropriate use and effectiveness of such new technologies. Accordingly, the Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat to review the literature on the effectiveness and utility of in-room air cleaners that use high-efficiency particle air (HEPA) filters and ultraviolet germicidal irradiation (UVGI) air cleaning technology. Additionally, the Ontario Health Technology Advisory Committee prioritized a request from the ministry’s Emergency Management Unit to investigate the possible role of the Plasmacluster ion air purifier manufactured by Sharp Electronics Corporation, in the pandemic influenza preparation plan. Clinical Need Airborne transmission of infectious diseases depends in part on the concentration of breathable infectious pathogens (germs) in room air. Infection control is achieved by a combination of administrative, engineering

  17. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  18. Air Quality Management Process Cycle

    Science.gov (United States)

    Air quality management are activities a regulatory authority undertakes to protect human health and the environment from the harmful effects of air pollution. The process of managing air quality can be illustrated as a cycle of inter-related elements.

  19. Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Office of Air and Radiation??s (OAR) Ambient Air Quality Data (Current) contains ambient air pollution data collected by EPA, other federal agencies, as well as...

  20. Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Office of Air and Radiation's (OAR) Ambient Air Quality Data (Current) contains ambient air pollution data collected by EPA, other federal agencies, as well as...

  1. Olefin metathesis in air

    Directory of Open Access Journals (Sweden)

    Lorenzo Piola

    2015-10-01

    Full Text Available Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  2. Air/Water Purification

    Science.gov (United States)

    1992-01-01

    After 18 years of research into air/water pollution at Stennis Space Center, Dr. B. C. Wolverton formed his own company, Wolverton Environmental Services, Inc., to provide technology and consultation in air and water treatment. Common houseplants are used to absorb potentially harmful materials from bathrooms and kitchens. The plants are fertilized, air is purified, and wastewater is converted to clean water. More than 100 U.S. communities have adopted Wolverton's earlier water hyacinth and artificial marsh applications. Catfish farmers are currently evaluating the artificial marsh technology as a purification system.

  3. Olefin metathesis in air

    Science.gov (United States)

    Piola, Lorenzo; Nahra, Fady

    2015-01-01

    Summary Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance. PMID:26664625

  4. Clean Air and Water

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    The air we breathe and the water we drink are both vital components of our health. Nevertheless, bacteria, pollutants, and other contaminates can alter life-giving air and water into health-threatening hazards. Learn about how scientists at the Centers for Disease Control and Prevention work to protect the public from air and water-related health risks.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  5. Air Quality Monitoring Programme

    DEFF Research Database (Denmark)

    Kemp, K.; Palmgren, F.

    The air quality in Danish cities has been monitored continuously since 1982 within the Danish Air Quality (LMP) network. The aim has been to follow the concentration levels of toxic pollutants in the urban atmosphere and to provide the necessary knowledge to assess the trends, to perform source...... apportionment, and to evaluate the chemical reactions and the dispersion of the pollutants in the atmosphere. In 2002 the air quality was measured in four Danish cities and at two background sites. NO2 and PM10 were at several stations found in concentrations above the new EU limit values, which the Member...

  6. Mid-air Acrobatics

    Institute of Scientific and Technical Information of China (English)

    LlU FENG'AN

    2011-01-01

    On September 1 two new aerobatic demonstration teams,theSky Wing and the Red Falcon,debuted at an air show held in Changchun,capital of northeast China's Jilin Province.The show was staged at a ceremony held by the Aviation University of the People's Liberation Army (PLA) Air Force.Also performing at the show was the 50-year-old Bayi aerobatic demonstration team.The teams demonstrated their superlative flying skills,which showcase the quality of the air force's rigorous pilot training.

  7. Fiscal 1996 project on the modeling for effective energy consumption in developing countries under a consignment from NEDO. Recent on the results of the demonstrative study on scrap preheater of electric furnace in the iron making process (for public); 1996 nendo hatten tojokoku energy shohi koritsuka model jigyo Shin Energy Sangyo Gijutsu Sogo Kaihatsu Kiko itaku. Seitetsu katei ni okeru denkiro no genryo yonetsu sochi ni kakawaru jissho kenkyu seika hokokusho (kokaiyo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Indonesia is the biggest iron steel producing country in the ASEAN countries. Most of the production is produced by the electric furnace method in which iron steel scrap is used as a material. However, an energy saving measure in this method, the electric furnace scrap preheater using flue gas, has not yet been spread on a full scale. This R and D is aimed at developing jointly with Indonesia an electric furnace scrap preheater for medium/small size electric furnaces which are adoptable to the present iron making situation in Indonesia and installing it to the electric furnace of the iron making plant in Indonesia for a demonstrative study on energy saving, etc. Spread/expansion of the electric furnace scrap preheater which is an excellent energy saving system targeted expansion of energy saving technology not only of Indonesia, but of ASEAN countries and Japan. In this fiscal year, remodeling of part of the system was made by change of flue gas flow for increasing the energy saving effect, and at the same time, a research study was made of a scrap reheater effective as a total system. Moreover, the paper investigated technical data/information in Japan and overseas. 3 figs., 9 tabs.

  8. Radioactive air sampling methods

    CERN Document Server

    Maiello, Mark L

    2010-01-01

    Although the field of radioactive air sampling has matured and evolved over decades, it has lacked a single resource that assimilates technical and background information on its many facets. Edited by experts and with contributions from top practitioners and researchers, Radioactive Air Sampling Methods provides authoritative guidance on measuring airborne radioactivity from industrial, research, and nuclear power operations, as well as naturally occuring radioactivity in the environment. Designed for industrial hygienists, air quality experts, and heath physicists, the book delves into the applied research advancing and transforming practice with improvements to measurement equipment, human dose modeling of inhaled radioactivity, and radiation safety regulations. To present a wide picture of the field, it covers the international and national standards that guide the quality of air sampling measurements and equipment. It discusses emergency response issues, including radioactive fallout and the assets used ...

  9. Natural Air Purifier

    Science.gov (United States)

    1993-01-01

    NASA environmental research has led to a plant-based air filtering system. Dr. B.C. Wolverton, a former NASA engineer who developed a biological filtering system for space life support, served as a consultant to Terra Firma Environmental. The company is marketing the BioFilter, a natural air purifier that combines activated carbon and other filter media with living plants and microorganisms. The filter material traps and holds indoor pollutants; plant roots and microorganisms then convert the pollutants into food for the plant. Most non-flowering house plants will work. After pollutants have been removed, the cleansed air is returned to the room through slits in the planter. Terra Firma is currently developing a filter that will also disinfect the air.

  10. Advanced air distribution

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2011-01-01

    The aim of total volume air distribution (TVAD) involves achieving uniform temperature and velocity in the occupied zone and environment designed for an average occupant. The supply of large amounts of clean and cool air are needed to maintain temperature and pollution concentration at acceptable...... levels in the entire space, leading to increased energy consumption and the use of large and costly HVAC and duct systems. The performance of desk installed PV combined with background TVAD used for room temperature control has been studied in an office building located in a hot and humid climate....... Ventilation in hospitals is essential to decrease the risk of airborne cross-infection. At present, mixing air distribution at a minimum of 12 ach is used in infection wards. Advanced air distribution has the potential to aid in achieving healthy, comfortable and productive indoor environments at levels...

  11. Regional Air Quality Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on regional air quality, including trace level SO2, nitric acid, ozone, carbon monoxide, and NOy; and particulate sulfate, nitrate, and...

  12. Temporal solitons in air

    Science.gov (United States)

    Voronin, A. A.; Zheltikov, A. M.

    2017-02-01

    Analysis of the group-velocity dispersion (GVD) of atmospheric air with a model that includes the entire manifold of infrared transitions in air reveals a remarkably broad and continuous anomalous-GVD region in the high-frequency wing of the carbon dioxide rovibrational band from approximately 3.5 to 4.2 μm where atmospheric air is still highly transparent and where high-peak-power sources of ultrashort midinfrared pulses are available. Within this range, anomalous dispersion acting jointly with optical nonlinearity of atmospheric air is shown to give rise to a unique three-dimensional dynamics with well-resolved soliton features in the time domain, enabling a highly efficient whole-beam soliton self-compression of such pulses to few-cycle pulse widths.

  13. Air Data Calibration Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility is for low altitude subsonic altimeter system calibrations of air vehicles. Mission is a direct support of the AFFTC mission. Postflight data merge is...

  14. Investigating Air Pollution

    Science.gov (United States)

    Carter, Edward J.

    1977-01-01

    Describes an experiment using live plants and cigarette smoke to demonstrate the effects of air pollution on a living organism. Procedures include growth of the test plants in glass bottles, and construction and operation of smoking machine. (CS)

  15. Air emission from the co-combustion of alternative derived fuels within cement plants: Gaseous pollutants.

    Science.gov (United States)

    Richards, Glen; Agranovski, Igor E

    2015-02-01

    Cement manufacturing is a resource- and energy-intensive industry, utilizing 9% of global industrial energy use while releasing more than 5% of global carbon dioxide (CO₂) emissions. With an increasing demand of production set to double by 2050, so too will be its carbon footprint. However, Australian cement plants have great potential for energy savings and emission reductions through the substitution of combustion fuels with a proportion of alternative derived fuels (ADFs), namely, fuels derived from wastes. This paper presents the environmental emissions monitoring of 10 cement batching plants while under baseline and ADF operating conditions, and an assessment of parameters influencing combustion. The experiential runs included the varied substitution rates of seven waste streams and the monitoring of seven target pollutants. The co-combustion tests of waste oil, wood chips, wood chips and plastic, waste solvents, and shredded tires were shown to have the minimal influence when compared to baseline runs, or had significantly reduced the unit mass emission factor of pollutants. With an increasing ADF% substitution, monitoring identified there to be no subsequent emission effects and that key process parameters contributing to contaminant suppression include (1) precalciner and kiln fuel firing rate and residence time; (2) preheater and precalciner gas and material temperature; (3) rotary kiln flame temperature; (4) fuel-air ratio and percentage of excess oxygen; and (5) the rate of meal feed and rate of clinker produced.

  16. Nanosecond Repetitively Pulsed Discharges in Air at Atmospheric Pressure -- Experiment and Theory of Regime Transitions

    Science.gov (United States)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

    In atmospheric pressure air preheated from 300 to 1000 K, the Nanosecond Repetitively Pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and inter-electrode gap distance) of each discharge regime. Notably, there is a minimum gap distance for the existence of the glow regime that increases with decreasing gas temperature. A theory is developed to describe the Corona-to-Glow (C-G) and Glow-to-Spark (G-S) transitions for NRP discharges. The C-G transition is shown to depend on the Avalanche-to-Streamer Transition (AST) as well as the electric field strength in the positive column. The G-S transition is due to the thermal ionization instability. The minimum gap distance for the existence of the glow regime can be understood by considering that the applied voltage of the AST must be lower than that of the thermal ionization instability. This is a previously unknown criterion for generating glow discharges, as it does not correspond to the Paschen minimum or to the Meek-Raether criterion.

  17. Metal hydride work pair development and its application on automobile air conditioning systems

    Institute of Scientific and Technical Information of China (English)

    QIN Feng; CHEN Jiang-ping; ZHANG Wen-feng; CHEN Zhi-jiu

    2007-01-01

    Aiming at developing exhaust gas driving automobile air conditioning systems, a hydride pair LaNi4.61Mn0.26A10.13/La0.6Y0.4Ni4.8Mn0.2 was developed working at 393~473 K/293~323 K/263~273 K. Property tests showed that both alloys have flat plateau slopes and small hystereses; system theoretical coefficient of performance (COP) is 0.711. Based on this work pair, a function proving automobile metal hydride refrigeration system was constructed. The equivalent thermal conductivities of the activated reaction beds were merely 1.1~1.6 W/(m·K), which had not met practical requirement. Intermittent refrigeration cycles were achieved and the average cooling power was 84.6 W at 423 K/303 K/273 K with COP being 0.26. By altering cycling parameters, experiment data showed that cooling power and system COP increase with the growth of heat source temperature as well as pre-heating and regeneration time while decrease with heat sink temperature increment. This study confirms the feasibility of automobile metal hydride refrigeration systems, while heat transfer properties of reaction beds still need to be improved for better performance.

  18. Indoor Air Pollution

    OpenAIRE

    Smith, Kirk R.

    2003-01-01

    Outdoor air pollution in developing-country cities is difficult to overlook. Indoor air pollution caused by burning such traditional fuels as wood, crop residues, and dung is less evident, yet it is responsible for a significant part of country and global disease burdens. The main groups affected are poor women and children in rural areas and urban slums as they go about their daily activi...

  19. Air Superiority Fighter Characteristics.

    Science.gov (United States)

    1998-06-05

    many a dispute could have been deflated into a single paragraph if the disputants had just dared to define their terms.7 Aristotle ...meaningful. This section will expand on some key ideology concepts. The phrase "air superiority fighter" may bring to mind visions of fighter... biographies are useful in garnering airpower advocate theories as well as identifying key characteristics. Air campaign results, starting with World

  20. Nuclear air cushion vehicles.

    Science.gov (United States)

    Anderson, J. L.

    1973-01-01

    This paper serves several functions. It identifies the 'state-of-the-art' of the still-conceptual nuclear air cushion vehicle, particularly the nuclear powerplant. Using mission studies and cost estimates, the report describes some of the advantages of nuclear power for large air cushion vehicles. The paper also summarizes the technology studies on mobile nuclear powerplants and conceptual ACV systems/missions studies that have been performed at NASA Lewis Research Center.

  1. INDOOR AIR QUALITY ANALYSIS

    OpenAIRE

    Wang, Xin

    2010-01-01

    With the development of modern architecture, one of the building's interior decoration, furnishings, appliances and equipment have become increasingly demanding, making construction of the indoor environment of increasing pollution, increasing pollution, indoor environmental pollution hazards to human is also a growing the greater. This thesis summarizes the major indoor air pollution sources and major pollutants. Indoor air pollutants are formaldehyde, radon, ammonia, total volatile org...

  2. Multipollutant air quality management.

    Science.gov (United States)

    Hidy, George M; Pennell, William T

    2010-06-01

    On the basis of a recent NARSTO assessment, this review discusses the factors involved in the implementation of a risk- and results-based multipollutant air quality management strategy applicable to North America. Such a strategy could evolve from current single-pollutant regulatory practices using a series of steps that would seek to minimize risk of exposure for humans and ecosystems while providing for a quantitative evaluation of the effectiveness of the management process. The tools needed to support multipollutant air quality management are summarized. They include application of a formal risk analysis, accounting for atmospheric processes, ambient measurements, emissions characterization, air quality modeling of emissions to ambient concentrations, and characterization of human and ecological responses to ambient pollutant exposure. The new management strategy would expand the current practice of accountability that relates emission reductions and attainment of air quality derived from air quality criteria and standards. Conceptually, achievement of accountability would establish goals optimizing risk reduction associated with pollution management. This expanded approach takes into account the sequence of processes from emissions reduction to resulting changes in ambient concentration. Using ambient concentration as a proxy for exposure, the resulting improvement in human and ecosystem health is estimated. The degree to which this chain of processes and effects can be achieved in current practice is examined in a multipollutant context exemplified by oxidants, as indicated by ozone, particulate matter, and some hazardous air pollutants. Achievement of a multipollutant management strategy will mostly depend on improving knowledge about human and ecosystem response to pollutant exposure.

  3. Fluidized Bed Air-to-Air Heat Pump Evaporator Evaluation.

    Science.gov (United States)

    1983-07-01

    Frost formation of air-to-air heat pump evaporator surfaces reduces unit efficiency and restricts application. The use of a fluidized bed heat...exchanger as an air-to- heat pump evaporator was investigated to determine if frost accumulation could be eliminated. Experimental investigations were...evaluated, with no practical solution being developed. The use of a fluidized bed heat exchanger for air-to-air heat pump evaporators was determined not feasible. (Author)

  4. 76 FR 9449 - National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

    Science.gov (United States)

    2011-02-17

    ... add carbon adsorbers to control the ore pre-heaters. Based on this beyond-the-floor analysis, we... controls on all thermal units at Nevada gold mines. According to the commenters, these permits are...

  5. Selection of Air Terminal Device

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,......This paper discusses the selection of the air terminal device for the experiments and numerical prediction in the International Energy Agency Annex 20 work: Air Flow Pattern within Buildings,...

  6. Computers in Air Defence

    Directory of Open Access Journals (Sweden)

    P. V.S. Rao

    1987-10-01

    Full Text Available With man's mastery over the third dimension - the near atmosphere and space- it has become increasingly necessary to protect oneself not merely from attacks from land and the sea but, more importantly, from attacks from the air. This was recognised even during the World War II and a rudimentary air defence capability was sought to be established; by the manul (visual surveillance and the anti-aircraft guns. The advent of radar signified a major advance in air defence technology and techniques. Rather than depend on visual observation and the hazards and limitations thereof, it became possible with radar to detect the presence of flying objects at much great distances. The PPI display of a conventional air-surveillance radar permits an operator to scan the sky for several hundreds of kilometers all around. Early radar-based air defence systems were dependent on human observation and decision making for detecting targets, identifying them, deciding on interception strategy and for recovering the interceptor after completion of his mission. This was feasible because, with a radar of between 200 to 400 kilometers and aircraft speeds in the range of 500 kilometers per hour, upto 30 minutes warning was available before the target was overhead.

  7. Urban Air Pollution in India

    OpenAIRE

    Narain, Urvashi

    2008-01-01

    This article describes the main efforts undertaken to stem the growth of air pollution in Indian cities. We begin by examining trends in air quality across the country. This is followed by a description of the legal and institutional framework and policies for controlling air pollution in India. Next we report on efforts to improve air quality in Delhi. We conclude by describing recent actions to control air pollution in cities other than Delhi.

  8. AirPort Extreme

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    AirPort Extreme是基于IEEE802.11g无线通讯协议的54Mbps的无线路由机站,它提供了比802.11b标准几乎快5倍以上的连接速率。AirPort Extreme基站可以同时为50台Mac和PC机用户服务。它支持从无线打印至带有USB接口或以太网接口的打印机,支持无线桥接技术,并同时提供了一整套强大的管理工具。除此之外,AirPort Extreme基站还配有一个内建防火墙,

  9. Urban Air Pollution Problems

    Energy Technology Data Exchange (ETDEWEB)

    Sivertsen, B.

    1995-09-01

    This document focuses on the specific problems of urban air pollution related to emissions, urban climate, meteorology, smog potential, specific locations, air pollution measurements and trends. Examples are given with cases from European cities in particular. The north south differences, coastal and inland problems and data from various parts of Europe are presented. Global trends and results from the UNEP programme are used to illustrate the magnitude of the problem. Special emphasis is placed on the impact of different sources and their importance in selected cities. Different types of atmospheric dispersion models, their development and use, is outlined. The importance of local and regional meteorological data for explanation purposes and for estimating and forecasting urban air quality is presented. Finally, monitoring programmes, mapping, impact assessment and optimum abatement strategy planning are illustrated with examples from different areas in the world. 9 refs., 56 figs., 1 table

  10. Air the excellent canopy

    CERN Document Server

    Fahy, F

    2013-01-01

    We take it for granted, but without it we perish and if we continue to abuse it, it may kill us in the end. This fascinating text provides an understanding and appreciation of the role that air plays in our environment and its importance in relation to human life and technology. Aimed at those who are scientifically curious but who have no specialist training, it contains no mathematical equations and relies upon the qualitative descriptions and analogies to explain the more technical parts of the text together with simple home experiments to illustrate a range of air-based phenomena. Liberall

  11. High Temperature Air/Steam Gasification of Biomass Wastes - Stage 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Blasiak, Wlodzimierz; Szewczyk, Dariusz; Lucas, Carlos; Rafidi, Nabil; Abeyweera Ruchira; Jansson, Anna; Bjoerkman, Eva [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Materials Science and Engineering

    2003-05-01

    In Jan 2002 the Division of Energy and Furnace Technology started the project High Temperature Air an Steam Gasification (HTAG) of biomass wastes, following the approval made by Swedish Energy Agency. The research proved successful; with the fixed bed updraft gasifier coupled to the highly regenerative preheater equipment able to produce a fuel gas not only from wood pellets but also from wood chips, bark and charcoal with considerably reduced amount of tar. This report provides information on solid biomass conversion into fuel gas as a result of air and steam gasification process performed in a fixed bed updraft gasifier. The first chapter of the report presents the overall objectives and the specific objectives of the work. Chapter 2 summarizes state-of-the-art on the gasification field stating some technical differences between low and high temperature gasification processes. Description and schemes of the experimental test rig are provided in Chapter 3. The equipment used to perform measurements of different sort and that installed in the course of the work is described in Chapter 4. Chapter 5 describes the methodology of experiments conducted whose results were processed and evaluated with help of the scheme of equations presented in Chapter 6, called raw data evaluation. Results of relevant experiments are presented and discussed in Chapter 7. A summary discussion of the tar analysis is presented in Chapter 8. Chapter 9 summarizes the findings of the research work conducted and identifies future efforts to ensure the development of next stage. Final chapter provides a summary of conclusions and recommendations of the work. References are provided at the end of the report. Aimed to assist the understanding of the work done, tables and graphs of experiments conducted, irrespective to their quality, are presented in appendices.

  12. Air movement - good or bad?

    DEFF Research Database (Denmark)

    Toftum, Jørn

    2004-01-01

    Air movement - good or bad? The question can only be answered by those who are exposed when they are exposed. Human perception of air movement depends on environmental factors including air velocity, air velocity fluctuations, air temperature, and personal factors such as overall thermal sensation...... and activity level. Even for the same individual, sensitivity to air movement may change from day to day as a result of e.g. different levels of fatigue. Based on existing literature, the current paper summarizes factors influencing the human perception of air movement and attempts to specify in general terms...... influences the subjective perception of air movement. With occupants feeling warmer than neutral, at temperatures above 23oC or at raised activity levels, humans generally do not feel draught at air velocities typical for indoor environments (up to around 0.4 m/s). In the higher temperature range, very high...

  13. Russia air management program

    Energy Technology Data Exchange (ETDEWEB)

    Pace, T.G. [U.S. Environmental Protection Agency, NC (United States); Markin, S. [Ministry of Environmental Protection and Natural Resources, Moscow (Sweden); Kosenkova, S.V. [Volgograd Environmental Services Administration, Volgograd (Russian Federation)

    1995-12-31

    The Russia Air Management Program is in the second year of a four-year cooperative program between the Russian Ministry of Environmental Protection and Natural Resources (MEPNR) and the U.S. Environmental Protection Agency (EPA) to improve national institutions, policies, and practices for air quality management in Russia. This program is part of the Environmental Policy and Technology project being conducted by the U.S. Agency for International Development. The Russia Air Management Program will pilot the application of potential air program improvements in the important industrial City of Volgograd which will enable the development, practical demonstration and evaluation of alternative approaches for improving AQM policies and practices in Russia. Volgograd has a progressive and environmentally enlightened local government, a diverse industrial base and a relatively healthy economy. It is located south of Moscow on the Volga River and was proposed by the Ministry of Environmental Protection and Natural Resources. It was selected after a site visit and a series of discussions with the Ministry, Volgograd officials, the World Bank and the EPA. Following the pilot, RAMP will work to facilitate implementation of selected parts of the pilot in other areas of Russia using training, technology transfer, and public awareness. (author)

  14. Air Structures: Inflatable Alternatives

    Science.gov (United States)

    Valerio, Joseph M.; And Others

    1973-01-01

    Describes and evaluates several avant garde'' examples of air structures. Included are a soft'' child's playpen, a pneudome that employs a water ballast for anchoring, a one-acre enclosed campus, an instant city'' constructed for an industrial design conference, and the Fuji Pavilion, at Expo '70 in Osaka, Japan, that was large enough to cover…

  15. Mid-air Acrobatics

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Two new aerobatic demonstration teams take to the skies On September 1,two new aerobatic demonstration teams,the Sky Wing and the Red Falcon,debuted at an air show held in Changchun,capital of northeast China’s Jilin Province.

  16. Hexane Air Combustion

    CERN Document Server

    Boettcher, Philipp A; Shepherd, Joseph E

    2010-01-01

    Hot surface ignition and subsequent flame propagation of premixed n-hexane air mixtures are shown in this fluid dynamics video. High speed schlieren photography revealed 3 distinct behaviors of ignition and propagation as a function of mixture composition and initial pressure.

  17. Images in the Air

    Science.gov (United States)

    Riveros, H. G.; Rosenberger, Franz

    2012-01-01

    This article discusses two "magic tricks" in terms of underlying optical principles. The first trick is new and produces a "ghost" in the air, and the second is the classical real image produced with two parabolic mirrors. (Contains 2 figure and 6 photos.)

  18. Air Blast Calculations

    Science.gov (United States)

    2013-07-01

    gauges at this point are still inside the explosive fireball (where the pressure time histories are dramatically influenced by the propagating...outside of the explosive fireball (since no evidence of an air-product interface is detected in any of the pressure time histories at this point

  19. Learning AirWatch

    CERN Document Server

    Dunkerley, Mark

    2015-01-01

    If you are a technical professional who wants to dive deeper into the functionality offered by AirWatch or manage the solution, then this book will help you choose the best set of configuration, device management, and monitoring options that you can use to effectively manage your EMM implementation.

  20. Tribal Air Quality Monitoring.

    Science.gov (United States)

    Wall, Dennis

    2001-01-01

    The Institute for Tribal Environmental Professionals (ITEP) (Flagstaff, Arizona) provides training and support for tribal professionals in the technical job skills needed for air quality monitoring and other environmental management tasks. ITEP also arranges internships, job placements, and hands-on training opportunities and supports an…

  1. Indoor Air Quality

    DEFF Research Database (Denmark)

    Selman, Ayser Dawod; Heiselberg, Per

    Overall purpose of the research is to provide an overview of the relevance and importance of various defined Indoor Air Quality (IAQ) parameters in a European perspective. Based on the report it should be possible to prioritize which countries to target for further activities as well as it should...

  2. Air Distribution in Rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The research on air distribution in rooms is often done as full-size investigations, scale-model investigations or by Computational Fluid Dynamics (CFD). New activities have taken place within all three areas and this paper draws comparisons between the different methods. The outcome of the l...

  3. Comparing toxic air pollutant programs

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, S.C. [ECKENFELDER Inc., Greenville, SC (United States)

    1997-05-01

    This article compares state and federal toxic air pollutant programs. The Clean Air Act Ammendments created a program for the control of Hazardous Air Pollutants based on the establishment of control technology standards. State toxic programs can be classified into two categories: control technology-based and ambient concentration-based. Many states have opened to implement the MACT standards while enforcing their own state air toxics programs. Specific topics discussed include the following: the Federal air toxics program; existing state regulations; New Jersey Air Toxic Program; New York Toxics program.

  4. Molecular Air Data Clear Air Turbulence Sensor: MADCAT Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Clear air turbulence (CAT), often referred to as "air pockets," is attributed to Kelvin-Helmholtz instabilities at altitudes generally above 18,000ft, often in the...

  5. Nitrogen fluorescence in air for observing extensive air showers

    CERN Document Server

    Keilhauer, B; Fraga, M; Matthews, J; Sakaki, N; Tameda, Y; Tsunesada, Y; Ulrich, A

    2012-01-01

    Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of \\emph{Air Fluorescence Workshops} commenced in 2002. At the 8$^{\\rm{th}}$ Air Fluoresc...

  6. Molecular Air Data Clear Air Turbulence Sensor: MADCAT Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Clear air turbulence (CAT), often referred to as "air pockets," is attributed to Kelvin-Helmholtz instabilities at altitudes usually above 18,000ft, often without...

  7. Air-Coupled Vibrometry

    Science.gov (United States)

    Döring, D.; Solodov, I.; Busse, G.

    Sound and ultrasound in air are the products of a multitude of different processes and thus can be favorable or undesirable phenomena. Development of experimental tools for non-invasive measurements and imaging of airborne sound fields is of importance for linear and nonlinear nondestructive material testing as well as noise control in industrial or civil engineering applications. One possible solution is based on acousto-optic interaction, like light diffraction imaging. The diffraction approach usually requires a sophisticated setup with fine optical alignment barely applicable in industrial environment. This paper focuses on the application of the robust experimental tool of scanning laser vibrometry, which utilizes commercial off-the-shelf equipment. The imaging technique of air-coupled vibrometry (ACV) is based on the modulation of the optical path length by the acoustic pressure of the sound wave. The theoretical considerations focus on the analysis of acousto-optical phase modulation. The sensitivity of the ACV in detecting vibration velocity was estimated as ~1 mm/s. The ACV applications to imaging of linear airborne fields are demonstrated for leaky wave propagation and measurements of ultrasonic air-coupled transducers. For higher-intensity ultrasound, the classical nonlinear effect of the second harmonic generation was measured in air. Another nonlinear application includes a direct observation of the nonlinear air-coupled emission (NACE) from the damaged areas in solid materials. The source of the NACE is shown to be strongly localized around the damage and proposed as a nonlinear "tag" to discern and image the defects.

  8. Air-cooled, hydrogen-air fuel cell

    Science.gov (United States)

    Shelekhin, Alexander B. (Inventor); Bushnell, Calvin L. (Inventor); Pien, Michael S. (Inventor)

    1999-01-01

    An air-cooled, hydrogen-air solid polymer electrolyte (SPE) fuel cell with a membrane electrode assembly operatively associated with a fluid flow plate having at least one plate cooling channel extending through the plate and at least one air distribution hole extending from a surface of the cathode flow field into the plate cooling channel.

  9. Nightfall: Machine Autonomy in Air-to-Air Combat

    Science.gov (United States)

    2014-06-01

    Debashis Chanda et al., “Large-Area Flexible 3D Optical Negative Index Metamaterial Formed by Nanotransfer Printing,” Nature Nanotechnology 6, no. 7 (July...article restricts the discussion to air-to-air applications because they present an extremely sterile environment compared to the air-to-ground (surface

  10. A Breath of Fresh Air: Addressing Indoor Air Quality

    Science.gov (United States)

    Palliser, Janna

    2011-01-01

    Indoor air pollution refers to "chemical, biological, and physical contamination of indoor air," which may result in adverse health effects (OECD 2003). The causes, sources, and types of indoor air pollutants will be addressed in this article, as well as health effects and how to reduce exposure. Learning more about potential pollutants in home…

  11. EN EL AIRE / In the air

    Directory of Open Access Journals (Sweden)

    Andrés López Fernández

    2011-11-01

    Full Text Available RESUMEN En el aire es un viaje a la primera mitad del siglo XX que nos tratará de acercar la frescura y oportunidad de las calles corredor y los jardines en la ciudad vertical. Se inicia en 1909 en Nueva York, con la publicación por la revista Life de La Torre del Globo, se acerca al Inmueble-Villas y al Plan Obus para Argel de Le Corbusier, y finaliza en 1952 con el proyecto para el conjunto residencial de Golden Lane en Londres de A. y P. Smithson. Fragmentos para la ciudad vertical que se construía sobre papel, tras el espejo, paralela en el tiempo, pero muy distinta a la ciudad real, con el objetivo entre otros de integrar arquitectura y naturaleza. Esas propuestas siguen teniendo hoy un gran valor, en un panorama en que el espacio público ligado a la vivienda colectiva, prácticamente ha desaparecido, y el esfuerzo que se demanda al arquitecto se centra, en tejer a modo de encaje de bolillos, una fachada que envuelva un programa de vivienda, funcional y espacialmente obsoleto.SUMMARY In the air, is a journey to the first half of the twentieth century that will try to bring us to the freshness and opportunity of the corridor streets and gardens in the vertical city. It begins in 1909 in New York, with the publication in Life magazine of the Globe Tower, it approaches the Immeubles-Villas and Plan Obus for Algiers by Le Corbusier, and ends in 1952 with the project for the Golden Lane Estate residential complex in London, by A. and P. Smithson. Fragments for the vertical city that was constructed on paper, behind the mirror, parallel in time, but was very different from the real city, with the aim, inter alia, of integrating architecture and nature. These proposals continue to have great value today, in a scenario where the public space linked to the collective home has virtually disappeared, and the effort that is demanded of the architect focuses on weaving a facade like bobbin lace around a functionally and spatially obsolete housing

  12. Use of air/ground heat exchangers for heating and cooling of buildings - in-situ measurements, analytical modeling, numerical simulation and system analysis[Dissertation 3357]; Utilisation des echangeurs air/sol pour le chauffage et le rafraichissement des batiments. Mesures in situ, modelisation analytique, simulation numerique et analyse systemique

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.

    2002-07-01

    In this thesis, physical properties and practical implementation of air/ground heat exchangers were studied. These exchangers consist in ducts placed in the upper ground layer (up to a depth of several meters). Air is circulated through the ducts, with heat transfer from and to the surrounding earth/sand/gravel material, with heat diffusion (conductive and capacitive effects) through this material. Air/ground heat exchangers are used to preheat or cool the air needed by the ventilation system of a building (open loop systems), or to heat up or cool the air in a greenhouse (closed loop systems). The reported study consisted in: (i) case studies of built examples, by detailed measuring and monitoring and data analysis. (ii) modeling the basic system. (iii) solving the basic equations both numerically (by computerized simulation) and analytically. (iv) identifying the basic features of these systems. (v) establishing recommendations for the practical implementation, especially in what regards sizing. It turned out that daily and seasonal heat storage/delivery by means of an air/ground heat exchanger have to be considered separately, with ad hoc rules of thumb each. Depending on parameter values a phase shift by as much as half the period may even be observed, with very little damping of the temperature oscillation. In Switzerland the main relevance for these systems is for improving thermal comfort in buildings in the summer time when outdoor temperature is higher than 26 {sup o}C, and for damping the amplitude of day/night temperature variations in horticultural greenhouses. The work carried out can be considered as of basic relevance for all applications of the systems studied.

  13. Studies efficiency solar air collector

    OpenAIRE

    YORKIN SODIKOVICH ABBASOV; MIRSOLI ODILJANOVICH UZBEKOV

    2016-01-01

    The article presents an analysis of the existing solar air collectors. A description of the design and the results of experimental studies on the effectiveness of the solar air collector with an absorber of from metal shavings.

  14. Air Compliance Complaint Database (ACCD)

    Data.gov (United States)

    U.S. Environmental Protection Agency — THIS DATA ASSET NO LONGER ACTIVE: This is metadata documentation for the Region 7 Air Compliance Complaint Database (ACCD) which logs all air pollution complaints...

  15. Introduction to Indoor Air Quality

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Indoor Air Quality (IAQ) Share ... indoor air pollution. For this reason, it is important to pay attention to the time and place ...

  16. Air Markets Program Data (AMPD)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Markets Program Data tool allows users to search EPA data to answer scientific, general, policy, and regulatory questions about industry emissions. Air...

  17. Aluminum/air electrochemical cells

    OpenAIRE

    Wang, Lei; 王雷

    2014-01-01

    Aluminum (Al) is a very promising energy carrier given its high capacity and energy density, low cost, earth abundance and environmental benignity. The Al/air battery as a kind of metal/air electrochemical cell attracts tremendous attention. Traditional Al/air batteries suffer from the self-corrosion and related safety problems. In this work, three new approaches were investigated to tackle these challenges and to develop high-performance Al/air cells: (1) incorporate an additional hydrogen/a...

  18. Iron-Air Rechargeable Battery

    Science.gov (United States)

    Narayan, Sri R. (Inventor); Prakash, G.K. Surya (Inventor); Kindler, Andrew (Inventor)

    2014-01-01

    Embodiments include an iron-air rechargeable battery having a composite electrode including an iron electrode and a hydrogen electrode integrated therewith. An air electrode is spaced from the iron electrode and an electrolyte is provided in contact with the air electrode and the iron electrodes. Various additives and catalysts are disclosed with respect to the iron electrode, air electrode, and electrolyte for increasing battery efficiency and cycle life.

  19. Hot Air Engines

    Directory of Open Access Journals (Sweden)

    P. Stouffs

    2011-01-01

    Full Text Available Invented in 1816, the hot-air engines have known significant commercial success in the nineteenth century, before falling into disuse. Nowadays they enjoy a renewed interest for some specific applications. The "hot-air engines" family is made up of two groups: Stirling engines and Ericsson engines. The operating principle of Stirling and Ericsson engines, their troubled history, their advantages and their niche applications are briefly presented, especially in the field of micro-combined heat and power, solar energy conversion and biomass energy conversion. The design of an open cycle Ericsson engine for solar application is proposed. A first prototype of the hot part of the engine has been built and tested. Experimental results are presented.

  20. Air transport system

    CERN Document Server

    Schmitt, Dieter

    2016-01-01

    The book addresses all major aspects to be considered for the design and operation of aircrafts within the entire transportation chain. It provides the basic information about the legal environment, which defines the basic requirements for aircraft design and aircraft operation. The interactions between  airport, air traffic management and the airlines are described. The market forecast methods and the aircraft development process are explained to understand the very complex and risky business of an aircraft manufacturer. The principles of flight physics as basis for aircraft design are presented and linked to the operational and legal aspects of air transport including all environmental impacts. The book is written for graduate students as well as for engineers and experts, who are working in aerospace industry, at airports or in the domain of transport and logistics.

  1. Aeromicrobiology/air quality

    Science.gov (United States)

    Andersen, Gary L.; Frisch, A.S.; Kellogg, Christina A.; Levetin, E.; Lighthart, Bruce; Paterno, D.

    2009-01-01

    The most prevalent microorganisms, viruses, bacteria, and fungi, are introduced into the atmosphere from many anthropogenic sources such as agricultural, industrial and urban activities, termed microbial air pollution (MAP), and natural sources. These include soil, vegetation, and ocean surfaces that have been disturbed by atmospheric turbulence. The airborne concentrations range from nil to great numbers and change as functions of time of day, season, location, and upwind sources. While airborne, they may settle out immediately or be transported great distances. Further, most viable airborne cells can be rendered nonviable due to temperature effects, dehydration or rehydration, UV radiation, and/or air pollution effects. Mathematical microbial survival models that simulate these effects have been developed.

  2. Pupils' Understanding of Air Pollution

    Science.gov (United States)

    Dimitriou, Anastasia; Christidou, Vasilia

    2007-01-01

    This paper reports on a study of pupils' knowledge and understanding of atmospheric pollution. Specifically, the study is aimed at identifying: 1) the extent to which pupils conceptualise the term "air pollution" in a scientifically appropriate way; 2) pupils' knowledge of air pollution sources and air pollutants; and 3) pupils' knowledge of air…

  3. Overview of Emerging Air Sensors

    Science.gov (United States)

    These slides will be presented at the 2014 National Ambient Air Monitoring Conference in Atlanta, GA during August 11-15, 2014. The goal is to provide an overview of air sensor technology and the audience will be primarily state air monitoring agencies and EPA Regions.

  4. Improving IAQ Via Air Filtration.

    Science.gov (United States)

    Monk, Brian

    1999-01-01

    Provides tips on using air filtration to control indoor air quality in educational facilities, including dedicated spaces with unique air quality conditions such as in libraries, museums and archival storage areas, kitchens and dining areas, and laboratories. The control of particulate contaminants, gaseous contaminants, and moisture buildup are…

  5. Air Pollution Primer. Revised Education.

    Science.gov (United States)

    Corman, Rena

    This revised and updated book is written to inform the citizens on the nature, causes, and effects of air pollution. It is written in terms familiar to the layman with the purpose of providing knowledge and motivation to spur community action on clean air policies. Numerous charts and drawings are provided to support discussion of air pollution…

  6. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU......) and Spencer C. Sorenson (ET). The theory which decribes in detail the overall dynamic chracteristics of the sensor was developed at IAU, DTU....

  7. Air Conditioning Overflow Sensor

    Science.gov (United States)

    1996-01-01

    The Technology Transfer Office at Stennis Space Center helped a local inventor develop a prototype of an attachment for central air conditioners and heat pumps that helps monitor water levels to prevent condensation overflow. The sensor will indicate a need for drain line maintenance and prevent possible damage caused by drain pan water spillover. An engineer in the Stennis Space Center prototype Development Laboratory used SSC sensor technology in the development of the sensor.

  8. Air Cargo Security

    Science.gov (United States)

    2007-07-30

    passenger and all-cargo aircraft. The air cargo system consists of a large, complex distribution network linking manufacturers and shippers to freight...free transportation to San Jose, California. His only luggage was a guitar case that concealed hammers, mallets, a knife, and a spear gun. At the...authorities and airplane manufacturers study methods to mitigate the effects of in-flight explosions.76 The FAA has had a active research program in blast

  9. Dental Compressed Air Systems.

    Science.gov (United States)

    1992-03-01

    compressor ex- cept that the piston rings are made of a low friction material (usually a Teflon- composite ) The piston walls are oil-less and all friction... descal - ing. The water-cooled models are smaller, more efficient, and cause less heating of room air. Water-cooled aftercoolers must have an...dry to a dew point of -400C (-400 F). It has high adsorption capacity. (b) Silica Gel , which must be protected from liquid (usually by a layer of

  10. Clearing the Air

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2011-01-01

    On November 8,seven Beijing residents,including a representative from a local environmental organization,were invited by the Beijing Municipal Environmental Protection Bureau (BMEPB)to visit its air-quality monitoring center,The visit was the first of a regular program of visits that will take 40 visitors to the center every Tuesday in hopes of giving them a betttr understanding of how airquality data are collected and analyzed.

  11. Air Consumption Analysis of Air-Jet Weaving

    Directory of Open Access Journals (Sweden)

    RAJ KUMAR KHIANI

    2016-07-01

    Full Text Available In Textile industry, production is mostly key concern for Industry owner. This always has attracted researchers and machines manufacturers to make new developments in process and machines. Air-jet is one of the leading and successful highest productive weaving machines. However, it is now well established that due to add of charges of compressed air, manufacturing cost of air-jet weaving machine is higher as compared with rapier and projectile weaving machines. This is why countries having energy issues do not prefer air-jet weaving machines comparing projectile weaving machines. In this regard, several researchers and machine manufacturers have continuously been working to improve the efficiency of air-jet weft insertion. However, industry practice is as important as design made by researchers. The aim of this research is to investigate the air consumption of air-jet weaving on industrial scale practice. In this study, five weaving machine of same manufacturer and model were selected. It was observed that despite of manufacturing same quality of fabric, air consumption was varying almost in all weaving machines. Conventionally, mill workers adopt hit and trial practice in weaving industry including airpressure setting which leads to variation of nozzle pressure. Main reason of disparity of air consumption in air-jet weaving machines may be variation of distance from compressor to weaving machines, number of joints, un-necessary valve opening and pipes leakages cause an increase of compressed air consumption.

  12. Enhancing indoor air quality –The air filter advantage

    Directory of Open Access Journals (Sweden)

    Vannan Kandi Vijayan

    2015-01-01

    Full Text Available Air pollution has become the world's single biggest environmental health risk, linked to around 7 million deaths in 2012 according to a recent World Health Organisation (WHO report. The new data further reveals a stronger link between, indoor and outdoor air pollution exposure and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. The role of air pollution in the development of respiratory diseases, including acute respiratory infections and chronic obstructive pulmonary diseases, is well known. While both indoor and outdoor pollution affect health, recent statistics on the impact of household indoor pollutants (HAP is alarming. The WHO factsheet on HAP and health states that 3.8 million premature deaths annually - including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD and lung cancer are attributed to exposure to household air pollution. Use of air cleaners and filters are one of the suggested strategies to improve indoor air quality. This review discusses the impact of air pollutants with special focus on indoor air pollutants and the benefits of air filters in improving indoor air quality.

  13. Air System Information Management

    Science.gov (United States)

    Filman, Robert E.

    2004-01-01

    I flew to Washington last week, a trip rich in distributed information management. Buying tickets, at the gate, in flight, landing and at the baggage claim, myriad messages about my reservation, the weather, our flight plans, gates, bags and so forth flew among a variety of travel agency, airline and Federal Aviation Administration (FAA) computers and personnel. By and large, each kind of information ran on a particular application, often specialized to own data formats and communications network. I went to Washington to attend an FAA meeting on System-Wide Information Management (SWIM) for the National Airspace System (NAS) (http://www.nasarchitecture.faa.gov/Tutorials/NAS101.cfm). NAS (and its information infrastructure, SWIM) is an attempt to bring greater regularity, efficiency and uniformity to the collection of stovepipe applications now used to manage air traffic. Current systems hold information about flight plans, flight trajectories, weather, air turbulence, current and forecast weather, radar summaries, hazardous condition warnings, airport and airspace capacity constraints, temporary flight restrictions, and so forth. Information moving among these stovepipe systems is usually mediated by people (for example, air traffic controllers) or single-purpose applications. People, whose intelligence is critical for difficult tasks and unusual circumstances, are not as efficient as computers for tasks that can be automated. Better information sharing can lead to higher system capacity, more efficient utilization and safer operations. Better information sharing through greater automation is possible though not necessarily easy.

  14. Air transparent soundproof window

    Directory of Open Access Journals (Sweden)

    Sang-Hoon Kim

    2014-11-01

    Full Text Available A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  15. Solid-Sorbent Air Sampler

    Science.gov (United States)

    Galen, T. J.

    1986-01-01

    Portable unit takes eight 24-hour samples. Volatile organic compounds in air collected for analysis by portable, self-contained sampling apparatus. Sampled air drawn through sorbent material, commercial porous polymer of 2, 3-diphenyl-p-phenylene oxide. High-boiling-point organic compounds adsorbed onto polymer, while low-boiling-point organics pass through and returned to atmosphere. Sampler includes eight sample tubes filled with polymeric sorbent. Organic compounds in atmosphere absorbed when air pumped through sorbent. Designed for checking air in spacecraft, sampler adaptable to other applications as leak detection, gas-mixture analysis, and ambient-air monitoring.

  16. Air Risk Information Support Center

    Energy Technology Data Exchange (ETDEWEB)

    Shoaf, C.R.; Guth, D.J. [Environmental Protection Agency, Washington, DC (United States)

    1990-12-31

    The Air Risk Information Support Center (Air RISC) was initiated in early 1988 by the US Environmental Protection Agency`s (EPA) Office of Health and Environmental Assessment (OHEA) and the Office of Air Quality Planning and Standards (OAQPS) as a technology transfer effort that would focus on providing information to state and local environmental agencies and to EPA Regional Offices in the areas of health, risk, and exposure assessment for toxic air pollutants. Technical information is fostered and disseminated by Air RISCs three primary activities: (1) a {open_quotes}hotline{close_quotes}, (2) quick turn-around technical assistance projects, and (3) general technical guidance projects. 1 ref., 2 figs.

  17. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  18. Air Quality at Your Street

    DEFF Research Database (Denmark)

    Jensen, Steen Solvang; Becker, Thomas; Ketzel, Matthias

    DTU Transport as well as data on travel speeds based on GPS data from SpeedMap from the Danish Road Directorate. Modelled concentrations have been compared to fixed regional, urban background and street air quality monitoring stations to assess uncertainties, and to model results from about 30 streets......Citizens are frequently concerned about the air quality where they live, where they go to work, where their children go to kindergarten or where they want to move to. Municipalities may also have an interest in location based air quality information e.g. in relation to screening of complaints from...... concerned citizents, or in the context of localization of institutions, etc. The purpose of the project ‘Air Quality at Your Street’ is to create interactive air quality maps on the internet using webGIS to illustrate the geographical variation of air quality in Denmark for selected health related air...

  19. Indoor Air Pollution (Environmental Health Student Portal)

    Science.gov (United States)

    Skip Navigation National Library of Medicine Environmental Health Student Portal Connecting Middle School Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air ...

  20. Inyección de aire secundario caliente en calderas de vapor bagaceras y su influencia en el rendimiento térmico Injection of heated secondary air in steam bagasse boilers and its influence on thermal efficiency

    Directory of Open Access Journals (Sweden)

    Marcos A. Golato

    2005-12-01

    Full Text Available Como alternativa para aumentar la eficiencia térmica de calderas bagaceras productoras de vapor, se evalúa la inyección de aire secundario al hogar, previamente calentado. Además, se reúne información sobre la combustión y los factores que influyen en dicho fenómeno. Se calculó el rendimiento térmico en una caldera bagacera con inyección de aire secundario frío, mediante el empleo de balances de masa y energía con datos de ensayos experimentales. Se planteó luego un modelo teórico para el caso de calentar todo este aire secundario, y se determinó el nuevo rendimiento térmico. Finalmente se realizó un análisis técnico-económico para evaluar la rentabilidad del uso de esta tecnología, teniendo en cuenta el ahorro de bagazo y su equivalente en gas natural. Para el caso analizado, los resultados mostraron: aumento del rendimiento térmico de la caldera (1,62 puntos; mejora del índice de generación de vapor (2,27%; reducción del consumo de bagazo (2,45%; aceptable periodo de repago de la inversión (114 días de zafra.Previously heated secondary air injection is evaluated as an alternative to increase thermal efficiency of bagasse steam boilers. Aspects regarding the combustion process and the factors affecting it are also described. Tests were made in a bagasse boiler of a sugar mill. Thermal efficiency of the bagasse boiler with cold secondary air injection was determined by solving mass and energy balances. A new thermal efficiency for the case in which all secondary air is pre-heated with hot gases was determined afterwards. Finally, a technical-economic analysis was made to evaluate the yield of this technology, taking into account bagasse saving and its equivalent in natural gas. For the analyzed case, the results showed: an increase in the thermal efficiency of the boiler (1,62 points; a higher steam production index (2,27%; a reduction in bagasse consumption (2,45%; an acceptable payback period of the investment (114

  1. Comparison between Different Air Distribution Systems

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The aim of an air conditioning system is to remove excess heat in a room and replace room air with fresh air to obtain a high air quality. It is not sufficient to remove heat and contaminated air, it is also necessary to distribute and control the air movement in the room to create thermal comfort...

  2. Extensive air showers

    CERN Document Server

    Rao, M V S

    1997-01-01

    Ultrahigh energy cosmic rays carry information about their sources and the intervening medium apart from providing a beam of particles for studying certain features of high energy interactions currently inaccessible at man-made accelerators. They can at present be studied only via the extensive air showers (EAS's) they generate while passing through the Earth's atmosphere, since their fluxes are too low for the experiments of limited capability flown in balloons and satellites. The EAS is generated by a series of interactions of the primary cosmic ray and its progeny with the atmospheric nucle

  3. Solid sorbent air sampler

    Science.gov (United States)

    Galen, T. J.

    1986-04-01

    A fluid sampler for collecting a plurality of discrete samples over separate time intervals is described. The sampler comprises a sample assembly having an inlet and a plurality of discreet sample tubes each of which has inlet and outlet sides. A multiport dual acting valve is provided in the sampler in order to sequentially pass air from the sample inlet into the selected sample tubes. The sample tubes extend longitudinally of the housing and are located about the outer periphery thereof so that upon removal of an enclosure cover, they are readily accessible for operation of the sampler in an analysis mode.

  4. AIR VELOCITY SENSOR

    Institute of Scientific and Technical Information of China (English)

    潘本琛

    1992-01-01

    During the last twenty years there has been rapid progress in the use of automation in a wide range of industries,as well as in military, scientific application. However, the progress in the application of automatic control is often hindered by the lack of accurate, reliable measuring apparatus. An economic thermal couple air flow sensor with better linearity (accuracy is ±5% of full scale) has been successfully made at Trolex Ltd. Many other existing sensors fail in the application of industries because of non-linearity.

  5. Teatro al aire libre

    Directory of Open Access Journals (Sweden)

    Philippe Canac

    2016-11-01

    Full Text Available Siendo cada vez más frecuentes y numerosas las peregrinaciones a la basílica de Notre Dame, de Laus (Altos Alpes, su capacidad resultaba hace tiempo insuficiente para acoger a sus peregrinos. Este fue el motivo de crear, en un terreno situado ante el atrio de la basílica, un conjunto, que permitiese celebrar misas al aire libre, ceremonias litúrgicas o representaciones de teatro religioso y que dispusiese de todas las posibilidades para conseguir la libertad del juego escénico.

  6. Air Quality Monitoring Programme

    DEFF Research Database (Denmark)

    Kemp, K.; Palmgren, F.

    The Danish Air Quality Monitoring Programme (LMP IV) has been revised in accordance with the Framework Directive and the first three daughter directives of SO2, NOx/NO2, PM10, lead, benzene, CO and ozone. PM10 samplers are under installation and the installation will be completed during 2002....... The PM10 results from 2000 are spares, only TSP are thus included in this report. The data sets for year 2000 is complete for many stations. The monitoring programme consists of 10 stations plus 2 extra stations under the Municipality of Copenhagen. The SO2 and lead levels are still decreasing and far...

  7. Ag-Air Service

    Science.gov (United States)

    1981-01-01

    Econ, Inc.'s agricultural aerial application, "ag-air," involves more than 10,000 aircraft spreading insecticides, herbicides, fertilizer, seed and other materials over millions of acres of farmland. Difficult for an operator to estimate costs accurately and decide what to charge or which airplane can handle which assignment most efficiently. Computerized service was designed to improve business efficiency in choice of aircraft and determination of charge rates based on realistic operating cost data. Each subscriber fills out a detailed form which pertains to his needs and then receives a custom-tailored computer printout best suited to his particular business mix.

  8. Air gun wounding and current UK laws controlling air weapons.

    Science.gov (United States)

    Bruce-Chwatt, Robert Michael

    2010-04-01

    Air weapons whether rifles or pistols are, potentially, lethal weapons. The UK legislation is complex and yet little known to the public. Hunting with air weapons and the laws controlling those animals that are permitted to be shot with air weapons is even more labyrinthine due to the legal power limitations on the possession of air weapons. Still relatively freely available by mail order or on the Internet, an increasing number of deaths have been reported from the misuse of air weapons or accidental discharges. Ammunition for air weapons has become increasingly sophisticated, effective and therefore increasingly dangerous if misused, though freely available being a mere projectile without a concomitant cartridge containing a propellant and an initiator.

  9. Nitrogen fluorescence in air for observing extensive air showers

    Directory of Open Access Journals (Sweden)

    Tsunesada Y.

    2013-06-01

    Full Text Available Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of Air Fluorescence Workshops commenced in 2002. At the 8th Air Fluorescence Workshop 2011, it was suggested to develop a common way of describing the nitrogen fluorescence for application to air shower observations. Here, first analyses for a common treatment of the major dependences of the emission procedure are presented. Aspects like the contributions at different wavelengths, the dependence on pressure as it is decreasing with increasing altitude in the atmosphere, the temperature dependence, in particular that of the collisional cross sections between molecules involved, and the collisional de-excitation by water vapor are discussed.

  10. Nitrogen fluorescence in air for observing extensive air showers

    Science.gov (United States)

    Keilhauer, B.; Bohacova, M.; Fraga, M.; Matthews, J.; Sakaki, N.; Tameda, Y.; Tsunesada, Y.; Ulrich, A.

    2013-06-01

    Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of Air Fluorescence Workshops commenced in 2002. At the 8th Air Fluorescence Workshop 2011, it was suggested to develop a common way of describing the nitrogen fluorescence for application to air shower observations. Here, first analyses for a common treatment of the major dependences of the emission procedure are presented. Aspects like the contributions at different wavelengths, the dependence on pressure as it is decreasing with increasing altitude in the atmosphere, the temperature dependence, in particular that of the collisional cross sections between molecules involved, and the collisional de-excitation by water vapor are discussed.

  11. Air Traffic Flow Management

    CERN Document Server

    Ganu, Hrishikesh V

    2008-01-01

    Air Traffic Flow Management is the regulation of air traffic in order to avoid exceeding airport or flight sector capacity in handling traffic, and to ensure that available capacity is used efficiently. We have tried to explore the logic behind the claims by Bertsimas et.al about integral solutions to the LP relaxation of the Traffic Flow Management Problem(TFMP). Polyhedral theory only indicates that the stronger TFMP formulation of Bertsimas et.al might lead to integral solutions in some cases. Our computations indicate that the encouraging results reported by Bertsimas et.al are not merely fortuitous or due to their specific data set. Indeed, we found that the TFMP had integral solutions even in case of artificial data sets generated to include severe conflicts in the flight schedules. In our limited tests with 4-5 scenarios, we obtained non-integral solutions only once. This is of significant practical importance because, the LP relaxation can be solved even on small machines with low memory and processor...

  12. Extraction of nickel from nickel limonite ore using dissolved gaseous SO2 - air

    Science.gov (United States)

    Wulandari, Winny; Soerawidjaja, Tatang Hernas; Joshua, Stephen; Isradi, Hashfi Rijal

    2017-01-01

    This paper reports a method of extracting nickel from nickel limonite by using dissolved SO2-air in ambient pressure. This method has been reported in the literature to be having advantages of a high selectivity of nickel towards iron, and can be conducted at ambient condition. The purpose of this study is to determine the good condition of nickel extraction from limonite ore by conducting pre-treatment and varying temperature and pH. The experiments were carried out in a five-neck reactor and comprised of three steps: pre-treatment of sample by pre-heating at 650 °C, leaching of the pre-treated sample, and analysis. The leaching solution was analyzed by using AAS (Atomic Absorption Spectrometer) method to determine the concentration of nickel and iron in the solution. The operating parameters included the acidity pH level of 3, 4, or 5 and the temperature of 30, 55, and 80 °C. The leaching was carried out up to 180 min. The mineralogical analysis of the ore was conducted by using XRD (X-Ray Diffraction) analysis. It is found that the good condition was obtained at pH 3, temperature of 80 °C, and 180 min leaching time, with nickel leaching efficiency of 21% from original nickel content. The selectivity nickel towards iron, defined by the extracted nickel (%) divided by extracted iron (%), has been found up to 2743. This method shows that nickel extraction can be carried out at very mild condition, including low temperature, atmospheric pressure and low pH.

  13. Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-12-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

  14. Managing Air in Olympic Cities

    Directory of Open Access Journals (Sweden)

    Qing W. Tian

    2008-01-01

    Full Text Available The 21st century Olympic Agenda aims to align itself with the concept of sustainable development and has driven improved environmental quality in host cities, such as the Green Games in Sydney 2000 and the planned Beijing 2008 Games and in London 2012 as the Low Carbon Games. Air quality has long been a concern of Olympic mega-cities, although the air quality plans and strategies have often seemed short-lived and unsustainable in the long term. We have explored air quality data and air pollution control from seven Olympic cities: Mexico City, Los Angeles, Atlanta, Sydney and Athens and also Beijing and London which will host Olympic Games in near future. The study shows that despite a high altitude and air pollution problems, Mexico City had no clear environmental policy in place for the 1968 games. The characteristic smog of Los Angeles raised concerns about athletic performance at the Olympic Games of 1984, but there were limited efforts to tackle the ozone concentration during these games. The 1996 Atlanta Games represents a case where temporary public transport changes were used as a tactic to reduce air pollution. In Sydney a well planned sustainable strategy reduced air pollutants and CO2 emissions in 2000, but Athens' long efforts to improve air quality for the 2004 games were not wholly effective. Even where strategies proved successful the improvements in air quality seem short-lived. Current host cities Beijing and London are developing emission reduction plans. These have clear air quality objectives and are well intentioned. However, the improvements may be too narrow and may not be sustainable in the long term. Our analysis looks at the origins of success and failure and how more coherent improvements might be achieved and what would promote sustainable plans for air quality management at future games. The study illustrates the feedback between air pollution science and policy awareness.

  15. Material Transport with Air Jet

    Directory of Open Access Journals (Sweden)

    István Patkó

    2005-11-01

    Full Text Available In the field of industry, there are only a very few examples of material transportwith air jet, and one of these is the air jet loom. In this weaving technology, the weft (thetransversal yarn of the fabric is shot by air jet. This paper will set up the mathematicalmodel of yarn end movement. For a special case, I will specify a solution of the model.

  16. The Cost of Air Pollution

    OpenAIRE

    World Bank; Institute for Health Metrics and Evaluation

    2016-01-01

    The Cost of Air Pollution: Strengthening the economic case for action, a joint study of the World Bank and the Institute for Health Metrics and Evaluation (IHME), seeks to estimate the costs of premature deaths related to air pollution, to strengthen the case for action and facilitate decision making in the context of scarce resources. An estimated 5.5 million lives were lost in 2013 to diseases associated with outdoor and household air pollution, causing human suffering and reducing economic...

  17. Air and metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Lampinen, M.; Noponen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Applied Thermodynamics

    1998-12-31

    The main goal of the air and metal hydride battery project was to enhance the performance and manufacturing technology of both electrodes to such a degree that an air-metal hydride battery could become a commercially and technically competitive power source for electric vehicles. By the end of the project it was possible to demonstrate the very first prototype of the air-metal hydride battery at EV scale, achieving all the required design parameters. (orig.)

  18. "Air embolism during fontan operation"

    Directory of Open Access Journals (Sweden)

    Madan Mohan Maddali

    2014-01-01

    Full Text Available In patients with a right to left intracardiac shunt, air embolism results in an obligatory systemic embolization. Nonembolization of entrained air is described in a child with a single ventricle physiology who had earlier undergone bidirectional Glenn shunt construction and Damus-Kaye-Stansel anastomosis. The air entrainment was detected by intra-operative transesophageal echocardiography. The combined effect of a "diving bell" phenomenon and mild aortic valve regurgitation are suggested as the reasons for the confinement of air into the ventricle preventing catastrophic systemic embolization.

  19. [Air quality and climate change].

    Science.gov (United States)

    Loft, Steffen

    2009-10-26

    Air quality, health and climate change are closely connected. Ozone depends on temperature and the greenhouse gas methane from cattle and biomass. Pollen presence depends on temperature and CO2. The effect of climate change on particulate air pollution is complex, but the likely net effect is greater health risks. Reduction of greenhouse-gas emissions by reduced livestock production and use of combustion for energy production, transport and heating will also improve air quality. Energy savings in buildings and use of CO2 neutral fuels should not deteriorate indoor and outdoor air quality.

  20. Aerodynamical sealing by air curtains

    Science.gov (United States)

    Frank, Daria; Linden, Paul

    2015-11-01

    Air curtains are artificial high-velocity plane turbulent jets which are installed in a doorway in order to reduce the heat and the mass exchange between two environments. The performance of an air curtain is assessed in terms of the sealing effectiveness E, the fraction of the exchange flow prevented by the air curtain compared to the open-door situation. The main controlling parameter for air curtain dynamics is the deflection modulus Dm representing the ratio of the momentum flux of the air curtain and the transverse forces acting on it due to the stack effect. In this talk, we examine the influence of two factors on the performance of an air curtain: the presence of an additional ventilation pathway in the room, such as a small top opening, and the effects of an opposing buoyancy force which for example arises if a downwards blowing air curtain is heated. Small-scale experiments were conducted to investigate the E (Dm) -curve of an air curtain in both situations. We present both experimental results and theoretical explanations for our observations. We also briefly illustrate how simplified models developed for air curtains can be used for more complex phenomena such as the effects of wind blowing around a model building on the ventilation rates through the openings.

  1. Modern Air Situation Picture Display for Air Surveillance Radar Applications

    Directory of Open Access Journals (Sweden)

    M. Stamatović

    2013-06-01

    Full Text Available We have developed a modern air situation picture display applicable in air surveillance radars. The display is based on commercial of-the-shelf hardware and custom software. This paper is focused on the details of the development process. Comparison with a similar commercially available product is given too.

  2. Colorado Air Quality Control Regulations and Ambient Air Quality Standards.

    Science.gov (United States)

    Colorado State Dept. of Health, Denver. Div. of Air Pollution Control.

    Regulations and standards relative to air quality control in Colorado are defined in this publication. Presented first are definitions of terms, a statement of intent, and general provisions applicable to all emission control regulations adopted by the Colorado Air Pollution Control Commission. Following this, three regulations are enumerated: (1)…

  3. Norma Primaria de calidad del aire AIR QUALITY STANDARD

    Directory of Open Access Journals (Sweden)

    PATRICIA MATUS C.

    2002-04-01

    Full Text Available Las normas primarias de calidad del aire tienen por finalidad proteger la salud de la población de la contaminación atmosférica. Ellas establecen un nivel de riesgo socialmente aceptado. Este artículo describe los antecedentes considerados durante el proceso de actualización de la regulación vigente en Chile. Detalla conceptos sobre la calidad del aire, describe los efectos en la salud de los contaminantes, y el procedimiento seguido para fijar los nuevos estándares Finaliza enumerando la norma primaria de calidad del aire, sus valores y los limites definidos para ser considerados en el ámbito de la gestión de los episodios críticos o de alta contaminaciónThe main purpose of air quality standards is to protect people health from air pollution. They establish a socially accepted level of risk. This article describes the background information considered during the process for updating the current Chilean regulation. Concepts about quality of air, and the effects of the pollutants on the health are described. The procedure followed to fix the new standards is detailed. Finally we state the primary air quality norm, its values as well as the critical limits in order to control critical events of high air pollution

  4. Reactive Air Aluminization

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Chou, Y. S.; Stevenson, Jeffry W.

    2011-10-28

    Ferritic stainless steels and other alloys are of great interest to SOFC developers for applications such as interconnects, cell frames, and balance of plant components. While these alloys offer significant advantages (e.g., low material and manufacturing cost, high thermal conductivity, and high temperature oxidation resistance), there are challenges which can hinder their utilization in SOFC systems; these challenges include Cr volatility and reactivity with glass seals. To overcome these challenges, protective coatings and surface treatments for the alloys are under development. In particular, aluminization of alloy surfaces offers the potential for mitigating both evaporation of Cr from the alloy surface and reaction of alloy constituents with glass seals. Commercial aluminization processes are available to SOFC developers, but they tend to be costly due to their use of exotic raw materials and/or processing conditions. As an alternative, PNNL has developed Reactive Air Aluminization (RAA), which offers a low-cost, simpler alternative to conventional aluminization methods.

  5. Indoor air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Gold, D.R. (Channing Laboratory, Brigham and Women' s Hospital, Boston, MA (United States))

    1992-06-01

    This article summarizes the health effects of indoor air pollutants and the modalities available to control them. The pollutants discussed include active and passive exposure to tobacco smoke; combustion products of carbon monoxide; nitrogen dioxide; products of biofuels, including wood and coal; biologic agents leading to immune responses, such as house dust mites, cockroaches, fungi, animal dander, and urine; biologic agents associated with infection such as Legionella and tuberculosis; formaldehyde; and volatile organic compounds. An approach to assessing building-related illness and tight building' syndrome is presented. Finally, the article reviews recent data on hospital-related asthma and exposures to potential respiratory hazards such as antineoplastic agents, anesthetic gases, and ethylene oxide.88 references.

  6. Air Composition and Chemistry

    Science.gov (United States)

    Brimblecombe, Peter

    1996-01-01

    This book is about the atmosphere and humanity's influence on it. For this new edition, Brimblecombe has rewritten and updated much of the book. In the early chapters, he discusses the geochemical, biological and maritime sources of the trace gases. Next, he examines the chemistry of atmospheric gases, suspended particles, and rainfall. After dealing with the natural atmosphere, he examines the sources of air pollution and its effects, with all scenarios updated from the last edition. Scenarios include decline in health, damage to plants and animals, indoor pollution, and acid rain. The final chapters, also revised, are concerned with the chemistry and evolution of the atmospheres of the planets of the solar system. Students with an interest in chemistry and the environmental sciences will find this book highly valuable.

  7. de Buenos Aires

    Directory of Open Access Journals (Sweden)

    Joaquín Linne

    2014-01-01

    Full Text Available Esta investigación explora la situación de los cibercafés en la Ciudad de Buenos Aires y de su principalpoblación, los adolescentes de sectores populares. Aunque en los últimos años millones de adolescentes abandonaronestos espacios como consecuencia de la ampliación de la Internet hogareña, en sectores popularesmuchos adolescentes aún continúan asistiendo en busca de recreación lúdico-comunicativa, información eintegración social. La metodología utilizada consiste en 40 entrevistas en profundidad, observaciones participantesy análisis de contenido de perfiles de Facebook (n: 200. Entre los resultados, se destaca que lasprincipales prácticas de estos adolescentes son comunicativas y que estos espacios funcionan para ellos comoherramientas de alfabetización digital, sociabilidad entre pares e inclusión ciudadana.

  8. Metal hydride air conditioner

    Institute of Scientific and Technical Information of China (English)

    YANG; Ke; DU; Ping; LU; Man-qi

    2005-01-01

    The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi4.4 Mn0.26 Al0.34 / La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1, LaNi4.61Mn0. 26 Al0.13/La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1 and LaNi4.61 Mn0.26 Al0.13/La0.6 Y0.4 Ni4.8 Mn0. 2, were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small conditioning system was established by using LaNi4.61 Mn0.26 Al0. 13/La0.6 Y0.4 Ni4.8 Mn0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and Wnet =0.09 kW/kg.

  9. 77 FR 12524 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Lead Ambient Air Quality...

    Science.gov (United States)

    2012-03-01

    ... Ambient Air Quality Standards AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule...) under the Clean Air Act (CAA). This submittal incorporates the National Ambient Air Quality...

  10. Air Leakage Rates in Typical Air Barrier Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Atchley, Jerald Allen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Childs, Phillip W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-11-01

    Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

  11. Air Pollution Control, Part I.

    Science.gov (United States)

    Strauss, Werner, Ed.

    Authoritative reviews in seven areas of current importance in air pollution control are supplied in this volume, the first of a two-part set. Titles contained in this book are: "Dispersion of Pollutants Emitted into the Atmosphere,""The Formation and Control of Oxides of Nitrogen in Air Pollution,""The Control of Sulfur Emissions from Combustion…

  12. Screening in humid air plasmas

    Science.gov (United States)

    Filippov, Anatoly; Derbenev, Ivan; Dyatko, Nikolay; Kurkin, Sergey

    2016-09-01

    Low temperature air plasmas containing H2O molecules are of high importance for atmospheric phenomena, climate control, biomedical applications, surface processing, and purification of air and water. Humid air plasma created by an external ionization source is a good model of the troposphere where ions are produced by the galactic cosmic rays and decay products of air and soil radioactive elements such as Rn222. The present paper is devoted to study the ionic composition and the screening in an ionized humid air at atmospheric pressure and room temperature. The ionization rate is varied in the range of 101 -1018 cm-3s-1. The humid air with 0 - 1 . 5 % water admixture that corresponds to the relative humidity of 0 - 67 % at the air temperature equal to 20°C is considered. The ionic composition is determined on the analysis of more than a hundred processes. The system of 41 non-steady state particle number balance equations is solved using the 4th order Runge-Kutta method. The screening of dust particle charge in the ionized humid air are studied within the diffusion-drift approach. The screening constants are well approximated by the inverse Debye length and characteristic lengths of recombination and attachment processes. This work was supported by the Russian Science Foundation, Project No. 16-12-10424.

  13. Ozone as an air pollutant

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    1996-01-01

    A Danish new book on ozone as an air pollutant has been reviewed. The Book is "Ozon som luftforurening" by Jes Fenger, Published by "Danmarks Miljøundersøgelser, 1995.......A Danish new book on ozone as an air pollutant has been reviewed. The Book is "Ozon som luftforurening" by Jes Fenger, Published by "Danmarks Miljøundersøgelser, 1995....

  14. Human preference for air movement

    DEFF Research Database (Denmark)

    Toftum, Jørn; Melikov, Arsen Krikor; Tynel, A.;

    2002-01-01

    Human preference for air movement was studied at slightly cool, neutral, and slightly warm overall thermal sensations and at temperatures ranging from 18 deg.C to 28 deg.C. Air movement preference depended on both thermal sensation and temperature, but large inter-individual differences existed...

  15. A Breath of Fresh Air

    Science.gov (United States)

    Belew, Rachel

    2011-01-01

    One of the most important aspects of a healthy school--and one that, unfortunately, often falls by the wayside--is indoor air quality. The U.S. Government Accountability Office estimates that more than 15,000 schools nationwide report suffering from poor indoor air quality. According to the U.S. Environmental Protection Agency, schools with poor…

  16. Mind Your Indoor Air Quality

    Science.gov (United States)

    Mak, Lily

    2012-01-01

    When it comes to excelling in the classroom, it turns out the air students are breathing is just as important as the lessons they are learning. Studies show poor indoor air quality (IAQ) can lessen the comfort of students as well as staff--affecting concentration, attendance and student performance. It can even lead to lower IQs. What's more, poor…

  17. Vehicles and Particulate Air Pollution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The current scene relating to particles and vehicular emissions in UK is reviewed. The active research topics are health effects of particles, particle size and composition, modeling the fate of particles and assessing individual exposure. There is a National Air Quality Strategy combined with local air quality management which includes monitoring and assessment, dispersion modeling and development of management plans.

  18. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  19. Protective supplied breathing air garment

    Science.gov (United States)

    Childers, Edward L.; von Hortenau, Erik F.

    1984-07-10

    A breathing air garment for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap.

  20. `Energy storage` using liquid air

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.C. [Melbourne Univ., Parkville, VIC (Australia)

    1995-12-31

    Storage of liquid air is relatively simple, and the work needed to manufacture it is, at least in principle, entirely recoverable. Available energy densities seem excellent. Unfortunately the technology to use liquid air for energy storage has never been developed. The Phillips-Stirling and McMahon and Gifford air liquefiers, and a previous proposal by Smith, provide leads as to the form which the technology might take. This paper introduces the concept of `Exergy`, and how it can be utilized in the storage of liquid air. It concludes that liquid air seems to present some real advantages over batteries for energy storage. The development presents a challenge. Since battery technology is not making the huge advances promised, it could be time to take a more serious look at this alternative. (author). 4 figs., 14 refs.

  1. Picosecond laser filamentation in air

    Science.gov (United States)

    Schmitt-Sody, Andreas; Kurz, Heiko G.; Bergé, Luc; Skupin, Stefan; Polynkin, Pavel

    2016-09-01

    The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear self-action effects and air ionization is investigated experimentally and numerically. The model used for numerical analysis is based on the nonlinear propagator for the optical field coupled to the rate equations for the production of various ionic species and plasma temperature. Our results show that the phenomenon of plasma-driven intensity clamping, which has been paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions in the picosecond regime are limited and the pulse fluence is also clamped. In focused propagation geometry, a unique feature of picosecond filamentation is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for many applications including laser-guided electrical breakdown of air, channeling microwave beams and air lasing.

  2. Lithium-Air Cell Development

    Science.gov (United States)

    Reid, Concha M.; Dobley, Arthur; Seymour, Frasier W.

    2014-01-01

    Lithium-air (Li-air) primary batteries have a theoretical specific capacity of 11,400 Wh/kg, the highest of any common metal-air system. NASA is developing Li-air technology for a Mobile Oxygen Concentrator for Spacecraft Emergencies, an application which requires an extremely lightweight primary battery that can discharge over 24 hours continuously. Several vendors were funded through the NASA SBIR program to develop Li-air technology to fulfill the requirements of this application. New catalysts and carbon cathode structures were developed to enhance the oxygen reduction reaction and increase surface area to improve cell performance. Techniques to stabilize the lithium metal anode surface were explored. Experimental results for prototype laboratory cells are given. Projections are made for the performance of hypothetical cells constructed from the materials that were developed.

  3. Atmospheric Chemistry and Air Pollution

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Gaffney

    2003-01-01

    Full Text Available Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozone and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.

  4. Population Dynamics and Air Pollution

    DEFF Research Database (Denmark)

    Flachs, Esben Meulengracht; Sørensen, Jan; Bønløkke, Jacob

    2013-01-01

    Objective. To explore how three different assumptions on demographics affect the health impact of Danish emitted air pollution in Denmark from 2005 to 2030, with health impact modeled from 2005 to 2050. Methods. Modeled air pollution from Danish sources was used as exposure in a newly developed......) a static year 2005 population, (2) morbidity and mortality fixed at the year 2005 level, or (3) an expected development. Results. The health impact of air pollution was estimated at 672,000, 290,000, and 280,000 lost life years depending on demographic assumptions and the corresponding social costs at 430.......4 M€, 317.5 M€, and 261.6 M€ through the modeled years 2005–2050. Conclusion. The modeled health impact of air pollution differed widely with the demographic assumptions, and thus demographics and assumptions on demographics played a key role in making health impact assessments on air pollution....

  5. 22 CFR 228.22 - Air transportation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Air transportation. 228.22 Section 228.22... for USAID Financing § 228.22 Air transportation. (a) The eligibility of air transportation is... U.S. flag air carriers for all international air travel and transportation, unless such service...

  6. Air Safety Spinoffs

    Science.gov (United States)

    1977-01-01

    Weight saving-even a matter of a few pounds-is an important consideration in airplane design and . construction. Boeing saved 200 pounds simply by substituting a new type of compressed gas cylinder on their 747 commercial airliners. For quickly evacuating passengers in the event of a ground emergency the 747 escape chutes allow ' passengers to slide to safety from the two-story height of the cabin deck. The chutes pop out of exitways and are automatically inflated in seconds by compressed air stored in pressure vessels. Boeing's weight saving resulted from a recent changeover to a new type of pressure vessel built by Structural Composites Industries Inc. of Azusa, Cal. The company employs technology originally developed for rocket motor casings; the cylinders are constructed by winding fibers around an aluminum liner. This technique offers high strength for very low weight-in this case 60 percent less than the pressure vessels earlier used on the 747. Another contribution to improved air safety is an underwater locator device. Called the "Pinger," it uses sonar techniques to locate aircraft crashed in water-or, more specifically, to recover the flight recorder aboard the airplane. Its recovery provides clues as to what caused the accident and suggests measures to prevent similar future occurrences. Until recently, there was no way to recover flight recorders aboard aircraft lost in water crashes. The Pinger, now serving 95 percent of the airline industry, provides an answer. Key element of the Pinger system is a small, battery-powered transmitter, or homing beacon, included as part of the recorder package. For as long as 30 days, the transmitter sends out an acoustic signal from water depths up to 20,000 feet. The other element of the system is a receiver, used by search crews to home in on the transmitter's signal. Originating as a U.S. Navy project, this device was refined and further developed by NASA's Langley Research Center to retrieve submerged nose cones

  7. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  8. 78 FR 12267 - Revision of Air Quality Implementation Plan; California; Placer County Air Pollution Control...

    Science.gov (United States)

    2013-02-22

    ... Pollution Control District and Feather River Air Quality Management District; Stationary Source Permits... County Air Pollution Control District (PCAPCD) and Feather River Air Quality Management District (FRAQMD... of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Incorporation...

  9. Community Multi-scale Air Quality (CMAQ) Modeling System for Air Quality Management

    Science.gov (United States)

    CMAQ simultaneously models multiple air pollutants including ozone, particulate matter and a variety of air toxics to help air quality managers determine the best air quality management scenarios for their communities, regions and states.

  10. [Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

    Science.gov (United States)

    Bellucci Sessa, R; Riccio, G

    2004-01-01

    After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

  11. TASK TECHNICAL AND QUALITY ASSURANCE PLAN FOR OUT-OF-TANK DESTRUCTION OF TETRAPHENYLBORATE VIA WET AIR OXIDATION TECHNOLOGY: PHASE I - BENCH SCALE TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K

    2006-03-31

    injected into the pressurized waste stream, and the air/liquid mixture is preheated to the required reactor inlet temperature. The reactor provides sufficient retention time to allow the oxidation to approach the desired level of organic decomposition. Typical reaction time is about 30-120 minutes. Heat exchangers are routinely employed to recover energy contained in the reactor effluent to preheat the waste feed/air entering the reactor. Auxiliary energy, usually steam, is necessary for startup and can provide trim heat if required. Since the oxidation reactions are exothermic, sufficient energy may be released in the reactor to allow the WAO system to operate without any additional heat input. After cooling, the oxidized reactor effluent passes through a pressure control valve where the pressure is reduced. A separator downstream of the pressure control valve allows the depressurized and cooled vapor to separate from the liquid. Typical industrial WAO applications have a feed flow rate of 1 to 220 gallons per minute (gpm) per train, with a chemical oxygen demand (COD) from 10,000 to 150,000 mg/L (higher CODs with dilution). Note that catalysts, such as homogeneous copper and iron, their heterogeneous counterparts, or precious metals can be used to enhance the effectiveness (i.e., to lower temperature, pressure, and residence time as well as increase oxidation efficiencies) of the WAO reaction if deemed necessary.

  12. Radioxenon spiked air.

    Science.gov (United States)

    Watrous, Matthew G; Delmore, James E; Hague, Robert K; Houghton, Tracy P; Jenson, Douglas D; Mann, Nick R

    2015-12-01

    Four of the radioactive xenon isotopes ((131m)Xe, (133m)Xe, (133)Xe and (135)Xe) with half-lives ranging from 9 h to 12 days are produced from nuclear fission and can be detected from days to weeks following their production and release. Being inert gases, they are readily transported through the atmosphere. Sources for release of radioactive xenon isotopes include operating nuclear reactors via leaks in fuel rods, medical isotope production facilities, and nuclear weapons' detonations. They are not normally released from fuel reprocessing due to the short half-lives. The Comprehensive Nuclear-Test-Ban Treaty has led to creation of the International Monitoring System. The International Monitoring System, when fully implemented, will consist of one component with 40 stations monitoring radioactive xenon around the globe. Monitoring these radioactive xenon isotopes is important to the Comprehensive Nuclear-Test-Ban Treaty in determining whether a seismically detected event is or is not a nuclear detonation. A variety of radioactive xenon quality control check standards, quantitatively spiked into various gas matrices, could be used to demonstrate that these stations are operating on the same basis in order to bolster defensibility of data across the International Monitoring System. This paper focuses on Idaho National Laboratory's capability to produce three of the xenon isotopes in pure form and the use of the four xenon isotopes in various combinations to produce radioactive xenon spiked air samples that could be subsequently distributed to participating facilities.

  13. Airing Out Anthrax

    Science.gov (United States)

    2002-01-01

    The AiroCide TiO2 is an air-purifier that kills 93.3 percent of airborne pathogens that pass through it, including Bacillus anthraci, more commonly known as anthrax. It is essentially a spinoff of KES Science & Technology, Inc.'s Bio-KES system, a highly effective device used by the produce industry for ethylene gas removal to aid in preserving the freshness of fruits, vegetables, and flowers. The TiO2-based ethylene removal technology that is incorporated into the company's AiroCide TiO2 and Bio-KES products was first integrated into a pair of plant-growth chambers known as ASTROCULTURE(TM) and ADVANCED ASTROCULTURE(TM). Both chambers have housed commercial plant growth experiments in space on either the Space Shuttle or the International Space Station. The AiroCide TiO2 also has a proven record of destroying 98 percent of other airborne pathogens, such as microscopic dust mites, molds, and fungi. Moreover, the device is a verified killer of Influenza A (flu), E. coli, Staphylococcus aureas, Streptococcus pyogenes, and Mycoplasma pneumoniae, among many other harmful viruses.

  14. Breathe the air!

    CERN Multimedia

    2003-01-01

    Feeling a bit cooped up in your office? Want to share your interest in science and technology with others but your computer's heard it all before and your colleagues won't even listen anymore? Then here's the answer - come and get some fresh air with the Education and Communication Group. The Visits Service and the Press Office offer you the opportunity to come into contact with CERN visitors. - Be a guide! In becoming a guide you get the opportunity to introduce the Laboratory to vast array of visitors of all nationalities and ages and communicate to them your passion for science and technology. You can get involved as a CERN guide on various levels - giving presentations and tours of the Laboratory, but also leading a «Drôle de Physique» workshop and giving tours of Microcosm. Guides receive training. If you're interested, take a look at the Guides Homepage where all the relevant information and formalities are explained: http://www.cern.ch/guides See also the article in the Bulletin n°25/2002. - Fa...

  15. Solar air systems - built examples

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, S.R. [ed.] [Solararchitektur, ETH-Hoenggerberg, Zurich (Switzerland)

    1999-07-01

    Active solar systems for air heating are a straightforward yet efficient way of using solar energy to heat spaces, ventilation air and even domestic hot water. They offer important advantages over solar water systems, improved comfort and fuller use of solar gains compared with many passive solar systems and are a natural fit with mechanically ventilated buildings. Solar air systems become more economical when they serve multiple functions such as providing a sound barrier, a weatherskin, sunshading, inducing cooling and even electricity supply (hybrid PV/air). Thirty-five different buildings with successfully installed exemplary solar air systems in climates ranging from Canada and Norway to Italy are described and documented. The building types cover single family houses, apartment buildings, schools, sports halls, and industrial commercial buildings with six different configurations of solar air systems used. Each building is described over several pages, with plans, performance details and illustrations provided. An accompanying product catalogue identifies suppliers of the necessary equipment and offers advice on product selection. As well as giving architects and designers invaluable advice based on the experience from these projects, this book also illustrates clearly the wide range of applications and the many benefits of solar air systems. (author)

  16. Air Sensor Toolbox: Resources and Funding

    Science.gov (United States)

    EPA’s Air Sensor Toolbox provides information and guidance on new low-cost compact technologies for measuring air quality. It provides information to help citizens more effectively and accurately collect air quality data in their community.

  17. Profit goal set for airBaltic

    Index Scriptorium Estoniae

    2011-01-01

    Latvijas Krajbanka president arvab, et airBalticu olukorra stabiliseerimiseks läheb vähemalt aasta. AirBalticu senine juht Bertolt Flick võib hakata uue Vilniuse lennukompanii investoriks. AirBalticu uuest juhatusest

  18. Historical Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Historical Ambient Air Quality Data Inventory contains measured and estimated data on ambient air pollution for use in assessing air quality, assisting in...

  19. National Air Toxic Assessments (NATA) Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Air Toxics Assessment was conducted by EPA in 2002 to assess air toxics emissions in order to identify and prioritize air toxics, emission source types...

  20. High Altitude Clear Air Turbulence Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Air Force Flight Dynamics Laboratory conducted the High Altitude Clear Air Turbulence Project in the mid 1960s with the intention of better understanding air...

  1. Transportation, Air Pollution, and Climate Change

    Science.gov (United States)

    ... Share Facebook Twitter Google+ Pinterest Contact Us Transportation, Air Pollution, and Climate Change Accomplishments & Successes View successes from ... reduce carbon pollution. Carbon pollution from transportation Other Air Pollution Learn about smog, soot, ozone, and other air ...

  2. Air Pollution, Climate, and Heart Disease

    Science.gov (United States)

    ... of the American Heart Association Cardiology Patient Page Air Pollution, Climate, and Heart Disease Diane R. Gold , Jonathan ... http://www.epa.gov/greenheart/ . 7 What Is Air Pollution? Air pollution is a mixture of gases and ...

  3. INEEL AIR MODELING PROTOCOL ext

    Energy Technology Data Exchange (ETDEWEB)

    C. S. Staley; M. L. Abbott; P. D. Ritter

    2004-12-01

    Various laws stemming from the Clean Air Act of 1970 and the Clean Air Act amendments of 1990 require air emissions modeling. Modeling is used to ensure that air emissions from new projects and from modifications to existing facilities do not exceed certain standards. For radionuclides, any new airborne release must be modeled to show that downwind receptors do not receive exposures exceeding the dose limits and to determine the requirements for emissions monitoring. For criteria and toxic pollutants, emissions usually must first exceed threshold values before modeling of downwind concentrations is required. This document was prepared to provide guidance for performing environmental compliance-driven air modeling of emissions from Idaho National Engineering and Environmental Laboratory facilities. This document assumes that the user has experience in air modeling and dose and risk assessment. It is not intended to be a "cookbook," nor should all recommendations herein be construed as requirements. However, there are certain procedures that are required by law, and these are pointed out. It is also important to understand that air emissions modeling is a constantly evolving process. This document should, therefore, be reviewed periodically and revised as needed. The document is divided into two parts. Part A is the protocol for radiological assessments, and Part B is for nonradiological assessments. This document is an update of and supersedes document INEEL/INT-98-00236, Rev. 0, INEEL Air Modeling Protocol. This updated document incorporates changes in some of the rules, procedures, and air modeling codes that have occurred since the protocol was first published in 1998.

  4. Korean Air Excellence in Flight

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Korean Air with a fleet of 119 aircraft, is one of the world's top 20 airlines, and oper-ates almost 400 flights everyday to 90 cities in 33 countries. The airline has about 50 flights per week between the US and Asia from nine US gateways: New York, Los Angeles, Washington,Chicago, Dallas, San Francisco, Atlanta, Anchorage and Honolulu.The carrier is a founding member of SkyTeam, the global airline alliance partnering AeroMexico, Air France, Alitalia, CSA Czech Airlines, Continental Airlines, Delta Air Lines, KLM and Northwest Airlines to provide customers with extensive worldwide destina-tions, flights and services.

  5. Steerable percussion air drilling system

    Energy Technology Data Exchange (ETDEWEB)

    Bui, H.D.; Gray, M.A.; Oliver, M.S.

    1995-07-01

    In the Steerable Percussion Air Drilling System (SPADS), air percussion is used to drill directionally in hard formations. Compared to mud or air powered PDM motors, SPADS offers directional drilling at high penetration rate, reduced mud costs, negligible formation damage, and immediate indication of hole productivity. Field tests turned up problems ranging from tool design to operation procedures; remedies were developed. There is an optimum WOB (weight on bit) at which torque is reasonably low. The hammer was tested at three different line pressures (200, 300, 350 psig) at optimum WOB in granite, limestone, and sandstone.

  6. Air Parity: Re-Discovering Contested Air Operations

    Science.gov (United States)

    2016-06-01

    maritime theories to war fighting strategy in the air domain, specific to the air control spectrum. The author assesses the importance of translating...effort to accomplish strategic 11 National Security Strategy , 12. 12 Office of the Secretary of...Defense, Sustaining U.S. Global Leadership: Priorities for 21st Century Defense (2012), 4. 13 Office of the Chairman, Joint Chiefs of Staff, The

  7. Tandil, Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    María L. Bakker

    2006-01-01

    Full Text Available Se coleccionaron hojas maduras de ejemplares adultos de Populus alba, Populus deltoides, Robinia pseudoacacia, Ulmus pumila y Fraxinus americana del Campus Universitario, Tandil, Buenos Aires, Argentina (37° 19’S, 59° 08’O en febrero de 2004. La cera cuticular fue extraída, purificada, y el contenido y proporción relativa de n-alcanos de número impar de carbonos (C23C35 fue cuantificado mediante cromatografía gas-líquido capilar. La concentración total de n-alcanos (mg/kg MS fue P. alba (6935 > Robinia (1571 > P. deltoides (1379 > Ulmus (880 > Fraxinus (467. Los n-alcanos más abundantes en todas las especies fueron C27 y C29 que constituyeron entre 10 y 51% y entre 35 y 76% del total respectivamente, excepto en Fraxinus donde los más abundantes fueron C29 y C31 que constituyeron el 31 y 49% del total respectivamente. P. alba y P. deltoides difirieron no solo en la concentración total de n-alcanos sino también en la proporción relativa de C27 y C29, siendo C29 el n-alcano más abundante en la segunda especie (76% igual que en Robinia (75%. La presencia de nalcanos de número par de carbonos no fue detectable o resultó muy baja en general en todas las especies, con excepción de C26, C28 y C30, este último se destacó particularmente en Fraxinus.

  8. Rooftop Unitary Air Conditioner with Integral Dedicated Outdoor Air System

    Energy Technology Data Exchange (ETDEWEB)

    Tiax Llc

    2006-02-28

    Energy use of rooftop and other unitary air-conditioners in commercial applications accounts for about 1 quad (10{sup 15} Btu) of primary energy use annually in the U.S. [Reference 7]. The realization that this cooling equipment accounts for the majority of commercial building cooled floorspace and the majority also of commercial building energy use has spurred development of improved-efficiency equipment as well as development of stricter standards addressing efficiency levels. Another key market driver affecting design of rooftop air-conditioning equipment has been concern regarding comfort and the control of humidity. Trends for increases in outdoor air ventilation rates in certain applications, and the increasing concern about indoor air quality problems associated with humidity levels and moisture in buildings points to a need for improved dehumidification capability in air-conditioning equipment of all types. In many cases addressing this issue exacerbates energy efficiency, and vice versa. The integrated dedicated outdoor air system configuration developed in this project addresses both energy and comfort/humidity issues.

  9. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Westford, MA (United States)

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

  10. Experimental Research on the Thermal Performance of Unglazed Transpired Solar Air Collectors%无盖板渗透型太阳能空气集热器热性能的实验研究

    Institute of Scientific and Technical Information of China (English)

    高立新; 孙绍增; 王远锋

    2012-01-01

    Unglazed transpired solar air collectors have proven to be effective devices for ventilation air preheating and drying, which can be integrated with building easily. An experimental rig with solar col lector area of 2.2 m2 was set up to test the thermal performance of a solar air heating system based on un-glazed transpired solar collectors, and a series of experiments were conducted under real transient outdoor conditions from February 2009 to April 2009. Test results show that exit air temperature increase with increasing solar irradiation. The most important influencing factor on exit air temperature is solar irradiation, while the influence of ambient air temperature is negligible. Temperature rise decreases with increasing air flow rate, while collector thermal efficiency increases with increasing air flow rate. The average thermal efficiency of the experimental solar air heating system in the 3 - day test period was 58% , 63% , and 72% , respectively, which are higher than most conventional glazed flat - plate solar air collectors.%无盖板渗透型太阳能空气集热器是一种易于实现建筑一体化的高效新风预热及干燥装置.为了掌握无盖板渗透型集热器在实际工况下的热性能,建造了集热面积为2.2 m2的太阳能空气加热系统实验台,并在2009年2月至2009年4月对其热性能进行了户外瞬态实验研究.实验结果表明出口空气温度随辐射强度的增加而升高,太阳辐射强度是影响集热器出口空气温度的最重要因素,而室外空气温度的影响极小.空气温升随风量的增加而减小,集热器热效率随风量的增加而增大.在三个测试日中集热器的平均热效率分别为58%、63%和72%,高于普通平板太阳能空气集热器.

  11. Air Pollution: Current and Future Challenges

    Science.gov (United States)

    Despite the dramatic progress to date, air pollution continues to threaten Americans’ health and welfare. The main obstacles are climate change, conventional air pollution, and ozone layer depletion.

  12. Personal Air Vehicle Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation is a low aspect ratio all-lifting configuration for personal air vehicles. This configuration uses an architecture fundamentally different from...

  13. A Martian Air Battery Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will investigate an entirely new battery chemistry by developing A Martian Air Battery. Specifically the project will explore the concept of a Martian...

  14. Ozone - Current Air Quality Index

    Science.gov (United States)

    Local Air Quality Conditions Zip Code: State : My Current Location Forecast Current AQI AQI Loop More Maps AQI: Good (0 - ... About the Highest 5 Today's Forecasts Tomorrow's Forecasts Current AQI Metropolitan Baltimore, MD 101 Metropolitan Washington, DC ...

  15. 2011 NATA - Air Toxics Monitors

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes annual (2005 - 2013) statistics of measured ambient air toxics concentrations (in micrograms per cubic meter) and associated risk estimates for...

  16. US Air Force Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Worksheets containing pilot balloon data computed from releases at Air Force stations in the western United States. Elevation and azimuth angles are used to compute...

  17. US Air Force Base Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly observations taken by U.S. Air Force personnel at bases in the United States and around the world. Foreign observations concentrated in the Middle East and...

  18. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This custom-designed facility houses a suite of three air guns capable of generating accelerations up to 100,000 Gs and velocities up to 2,000 ft/s. In addition to...

  19. Air Pollution Affects Community Health

    Science.gov (United States)

    Shy, Carl M.; Finklea, John F.

    1973-01-01

    Community Health and Environmental Surveillance System (CHESS), a nationwide program relating community health to environmental quality, is designed to evaluate existing environmental standards, obtain health intelligence for new standards, and document health benefits of air pollution control. (BL)

  20. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This custom-designed facility houses a suite of three air guns capable of generating accelerations up to 100,000 Gs and velocities up to 2,000 ft/s. In addition to a...

  1. Indoor Air Quality Test House

    Data.gov (United States)

    Federal Laboratory Consortium — Description:In order to enable studies of a range of indoor air quality and ventilation issues, EL maintains a highly instrumented three-bedroom test house. Previous...

  2. Quality and Indoor Air treatment

    Directory of Open Access Journals (Sweden)

    Cécile HORT

    2008-01-01

    Full Text Available In developed countries, between 70% and 90% of the life time are spent in confined spaces (housing, transport, etc.. Air quality in these closed spaces is generally inferior than outside. Our lifestylesand the growing use of new products and materials create cocktails of chemicals compounds (COV, CIV... that can cause an increase of worrying diseases such as asthma, allergies or even cancer. These pollutants are particularly present in indoor air. These increasing public health problems gives rise to the development of devices for the treatment of indoor air. However, indoor air contains a lot of chemical substances showing very different physicochemical properties. The “Laboratoire de Thermique, Energétique et Procédés” (LaTEP studies the coupling of treatment processes, such as biofiltration coupled to adsorption.

  3. Air cushion vehicles: A briefing

    Science.gov (United States)

    Anderson, J. L.; Finnegan, P. M.

    1971-01-01

    Experience and characteristics; the powering, uses, and implications of large air cushion vehicles (ACV); and the conceptual design and operation of a nuclear powered ACV freighter and supporting facilities are described.

  4. 齐鲁塑料厂中央空调节能改造%ENERGY- SAVING REVAMP OF CENTRAL AIR CONDITIONER

    Institute of Scientific and Technical Information of China (English)

    王效敏

    2011-01-01

    The central air conditioner in Plastics Complex supplied heat with desalinated water as heat medium which was heated by medium - pressure steam through a exchanger. After revamp, condensed liquid in styrene process is mainly used to preheat desalinated water through heat exchanger, and then heat exchanger for medium - pressure steam is used to adjust the temperature of desalinated water. This method is steam saving by means of waste heat utilization.%齐鲁塑料厂中央空调由原来的中压蒸汽通过换热器加热脱盐水作为热媒供热,改造后主要用苯乙烯工艺凝液通过换热器预热脱盐水,然后用中压蒸汽换热器调整脱盐水到合适的温度后供热。达到利用工艺凝液的余热,节省中压蒸汽的目的。

  5. Global air quality and climate.

    Science.gov (United States)

    Fiore, Arlene M; Naik, Vaishali; Spracklen, Dominick V; Steiner, Allison; Unger, Nadine; Prather, Michael; Bergmann, Dan; Cameron-Smith, Philip J; Cionni, Irene; Collins, William J; Dalsøren, Stig; Eyring, Veronika; Folberth, Gerd A; Ginoux, Paul; Horowitz, Larry W; Josse, Béatrice; Lamarque, Jean-François; MacKenzie, Ian A; Nagashima, Tatsuya; O'Connor, Fiona M; Righi, Mattia; Rumbold, Steven T; Shindell, Drew T; Skeie, Ragnhild B; Sudo, Kengo; Szopa, Sophie; Takemura, Toshihiko; Zeng, Guang

    2012-10-07

    Emissions of air pollutants and their precursors determine regional air quality and can alter climate. Climate change can perturb the long-range transport, chemical processing, and local meteorology that influence air pollution. We review the implications of projected changes in methane (CH(4)), ozone precursors (O(3)), and aerosols for climate (expressed in terms of the radiative forcing metric or changes in global surface temperature) and hemispheric-to-continental scale air quality. Reducing the O(3) precursor CH(4) would slow near-term warming by decreasing both CH(4) and tropospheric O(3). Uncertainty remains as to the net climate forcing from anthropogenic nitrogen oxide (NO(x)) emissions, which increase tropospheric O(3) (warming) but also increase aerosols and decrease CH(4) (both cooling). Anthropogenic emissions of carbon monoxide (CO) and non-CH(4) volatile organic compounds (NMVOC) warm by increasing both O(3) and CH(4). Radiative impacts from secondary organic aerosols (SOA) are poorly understood. Black carbon emission controls, by reducing the absorption of sunlight in the atmosphere and on snow and ice, have the potential to slow near-term warming, but uncertainties in coincident emissions of reflective (cooling) aerosols and poorly constrained cloud indirect effects confound robust estimates of net climate impacts. Reducing sulfate and nitrate aerosols would improve air quality and lessen interference with the hydrologic cycle, but lead to warming. A holistic and balanced view is thus needed to assess how air pollution controls influence climate; a first step towards this goal involves estimating net climate impacts from individual emission sectors. Modeling and observational analyses suggest a warming climate degrades air quality (increasing surface O(3) and particulate matter) in many populated regions, including during pollution episodes. Prior Intergovernmental Panel on Climate Change (IPCC) scenarios (SRES) allowed unconstrained growth, whereas

  6. Global Air Quality and Climate

    Science.gov (United States)

    Fiore, Arlene M.; Naik, Vaishali; Steiner, Allison; Unger, Nadine; Bergmann, Dan; Prather, Michael; Righi, Mattia; Rumbold, Steven T.; Shindell, Drew T.; Skeie, Ragnhild B.; Sudo, Kengo; Szopa, Sophie; Horowitz, Larry W.; Takemura, Toshihiko; Zeng, Guang; Cameron-Smith, Philip J.; Cionni, Irene; Collins, William J.; Dalsoren, Stig; Eyring, Veronika; Folberth, Gerd A.; Ginoux, Paul; Josse, Batrice; Lamarque, Jean-Francois; OConnor, Fiona M.; Mackenzie, Ian A.; Nagashima, Tatsuya; Shindell, Drew Todd; Spracklen, Dominick V.

    2012-01-01

    Emissions of air pollutants and their precursors determine regional air quality and can alter climate. Climate change can perturb the long-range transport, chemical processing, and local meteorology that influence air pollution. We review the implications of projected changes in methane (CH4), ozone precursors (O3), and aerosols for climate (expressed in terms of the radiative forcing metric or changes in global surface temperature) and hemispheric-to-continental scale air quality. Reducing the O3 precursor CH4 would slow near-term warming by decreasing both CH4 and tropospheric O3. Uncertainty remains as to the net climate forcing from anthropogenic nitrogen oxide (NOx) emissions, which increase tropospheric O3 (warming) but also increase aerosols and decrease CH4 (both cooling). Anthropogenic emissions of carbon monoxide (CO) and non-CH4 volatile organic compounds (NMVOC) warm by increasing both O3 and CH4. Radiative impacts from secondary organic aerosols (SOA) are poorly understood. Black carbon emission controls, by reducing the absorption of sunlight in the atmosphere and on snow and ice, have the potential to slow near-term warming, but uncertainties in coincident emissions of reflective (cooling) aerosols and poorly constrained cloud indirect effects confound robust estimates of net climate impacts. Reducing sulfate and nitrate aerosols would improve air quality and lessen interference with the hydrologic cycle, but lead to warming. A holistic and balanced view is thus needed to assess how air pollution controls influence climate; a first step towards this goal involves estimating net climate impacts from individual emission sectors. Modeling and observational analyses suggest a warming climate degrades air quality (increasing surface O3 and particulate matter) in many populated regions, including during pollution episodes. Prior Intergovernmental Panel on Climate Change (IPCC) scenarios (SRES) allowed unconstrained growth, whereas the Representative

  7. Call for improving air quality

    Science.gov (United States)

    Showstack, Randy

    2013-01-01

    The European Environmental Bureau (EEB), a federation of citizen organizations, has called for stricter policies in Europe to protect human health and the environment. "Air pollution emanates from sources all around us, be they cars, industrial plants, shipping, agriculture, or waste. The [European Union] must propose ambitious legislation to address all of these sources if it is to tackle the grave public health consequences of air pollution," EEB secretary general Jeremy Wates said on 8 January.

  8. Cognitive abilities and air pollution

    Directory of Open Access Journals (Sweden)

    Raufhon Salahodjaev

    2016-12-01

    Full Text Available The link between intelligence and air pollution is subject to controversy. Some studies report that intelligence has insignificant effect in reducing the greenhouse gas emissions. By using carbon dioxide (CO2 emissions for a large set of countries we present further novel empirical evidence on the relation between level of intelligence and air pollution. Our findings suggest that the relation follows a U-shape pattern and resembles environmental Kuznets curve.

  9. Autonomy of the Air Arm

    Science.gov (United States)

    1996-01-01

    Lewis, and Maj. Gen. George Simonds. Standing, left to right: Brig. Gen. John Gulik, James Doolittle (at that time a civilian), Edgar Gorrell, Brig...official sanction of the War Department, was submitted by Representative John M. Morin ." 56 CREATION OF THE ARmy AIR CORPS The initial stages of the...reality was a revision of the Morin air bill. 47 A quick summary at this point should clarify the major issues under review. Through the medium of various

  10. The lithium air battery fundamentals

    CERN Document Server

    Imanishi, Nobuyuki; Bruce, Peter G

    2014-01-01

    Lithium air rechargeable batteries are the best candidate for a power source for electric vehicles, because of their high specific energy density. In this book, the history, scientific background, status and prospects of the lithium air system are introduced by specialists in the field. This book will contain the basics, current statuses, and prospects for new technologies. This book is ideal for those interested in electrochemistry, energy storage, and materials science.

  11. Small Break Air Ingress Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Eung Soo Kim

    2011-09-01

    The small break air-ingress experiment, described in this report, is designed to investigate air-ingress phenomena postulated to occur in pipes in a very high temperature gas-cooled reactor (VHTRs). During this experiment, air-ingress rates were measured for various flow and break conditions through small holes drilled into a pipe of the experimental apparatus. The holes were drilled at right angles to the pipe wall such that a direction vector drawn from the pipe centerline to the center of each hole was at right angles with respect to the pipe centerline. Thus the orientation of each hole was obtained by measuring the included angle between the direction vector of each hole with respect to a reference line anchored on the pipe centerline and pointing in the direction of the gravitational force. Using this reference system, the influence of several important parameters on the air ingress flow rate were measured including break orientation, break size, and flow velocity . The approach used to study the influence of these parameters on air ingress is based on measuring the changes in oxygen concentrations at various locations in the helium flow circulation system as a function of time using oxygen sensors (or detectors) to estimate the air-ingress rates through the holes. The test-section is constructed of a stainless steel pipe which had small holes drilled at the desired locations.

  12. Solar air heaters and their applications

    Science.gov (United States)

    Selcuk, M. K.

    1977-01-01

    The solar air heater appears to be the most logical choice, as far as the ultimate application of heating air to maintain a comfortable environment is concerned. One disadvantage of solar air heaters is the need for handling larger volumes of air than liquids due to the low density of air as a working substance. Another disadvantage is the low thermal capacity of air. In cases where thermal storage is needed, water is superior to air. Design variations of solar air heaters are discussed along with the calculation of the efficiency of a flat plate solar air heater, the performance of various collector types, and the applications of solar air heaters. Attention is given to collectors with nonporous absorber plates, collectors with porous absorbers, the performance of flat plate collectors with finned absorbers, a wire mesh absorber, and an overlapped glass plate air heater.

  13. A mixed air/air and air/water heat pump system ensures the air-conditioning of a cinema; Un systeme mixte PAC air/air et air/eau climatise un cinema

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-03-01

    This article presents the air conditioning system of a new cinema complex of Boulogne (92, France) which comprises a double-flux air processing plant and two heat pumps. Each heat pump has two independent refrigerating loops: one with a air condenser and the other with a water condenser. This system allows to limit the power of the loop and to reduce the size of the cooling tower and of the vertical ducts. This article describes the technical characteristics of the installation: thermodynamic units, smoke clearing, temperature control, air renewing. (J.S.)

  14. Air quality in Europe - 2012 report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    This report presents an overview and analysis of the status and trends of air quality in Europe based on concentration measurements in ambient air and data on anthropogenic emissions and trends from 2001 - when mandatory monitoring of ambient air concentrations of selected pollutants first produced reliable air quality information - to 2010. (Author)

  15. Ozone, Air Quality, and Asthma (For Parents)

    Science.gov (United States)

    ... gases can also affect lung function. continue How Poor Air Quality Affects People With Asthma Air pollution is a problem for ... to evening. In cities larger than 350,000 people, state and local agencies are ... days when air quality is poor, run the air conditioning and limit your child's ...

  16. Solid Waste, Air Pollution and Health

    Science.gov (United States)

    Kupchik, George J.; Franz, Gerald J.

    1976-01-01

    This article examines the relationships among solid waste disposal, air pollution, and human disease. It is estimated that solid waste disposal contributes 9.7 percent of the total air pollution and 9.9 percent of the total air pollution health effect. Certain disposal-resource recovery systems can be implemented to meet air quality standards. (MR)

  17. 29 CFR 1917.154 - Compressed air.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed...

  18. 30 CFR 75.321 - Air quality.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air quality. 75.321 Section 75.321 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.321 Air quality. (a)(1) The air in areas where... air current in these areas shall be sufficient to dilute, render harmless, and carry away...

  19. 32 CFR 989.30 - Air quality.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Air quality. 989.30 Section 989.30 National... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.30 Air quality. Section 176(c) of the Clean Air Act..., Air Quality Compliance. 10 10 See footnote 1 to § 989.1....

  20. Disparities in the Impact of Air Pollution

    Science.gov (United States)

    ... Outdoor > Air Pollution Disparities in the Impact of Air Pollution The burden of air pollution is not evenly shared. Poorer people and some ... studies have explored the differences in harm from air pollution to racial or ethnic groups and people who ...

  1. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    are conducted. Results were not originally presented in a way, which made comparison possible. Here the amount of scaled material is depicted as function of air voids parameters: total air content, specific surface, spacing factor, and total surface area of air voids. The total surface area of air voids...... is proportional to the product of total air content and specific surface. In all 4 cases, the conclusion is concurrent that the parameter of total surface area of air voids performs equally well or better than the spacing factor when linking air void characteristics to frost resistance (salt frost scaling...... on that capillary pores are connected to air voids. The chance that a capillary pore is connected to an air void depends on the total surface area of air voids in the system, not the spacing factor....

  2. Chapter 22: Compressed Air Evaluation Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Benton, N.

    2014-11-01

    Compressed-air systems are used widely throughout industry for many operations, including pneumatic tools, packaging and automation equipment, conveyors, and other industrial process operations. Compressed-air systems are defined as a group of subsystems composed of air compressors, air treatment equipment, controls, piping, pneumatic tools, pneumatically powered machinery, and process applications using compressed air. A compressed-air system has three primary functional subsystems: supply, distribution, and demand. Air compressors are the primary energy consumers in a compressed-air system and are the primary focus of this protocol. The two compressed-air energy efficiency measures specifically addressed in this protocol are: high-efficiency/variable speed drive (VSD) compressor replacing modulating compressor; compressed-air leak survey and repairs. This protocol provides direction on how to reliably verify savings from these two measures using a consistent approach for each.

  3. Development and benefits of air/air-heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, H.W.; Cremer, P.

    1986-02-01

    After the first experiments using glass tube heat exchangers, many air/air heat exchangers have made within ten years the breakthrough as ''interior climate improvers'' in stables. Especially inexpensive synthetic panels, foils and self-construction, ribbed heat exchangers are very popular among farmers. Based on thorough installation planning and satisfactory operating results, thousands of heat exchangers were installed, through which heating oil and fuel gas are being replaced as energy sources, and through an improved interior climate, the productivity can be optimized in fattening and rearing houses. (orig.).

  4. Unit for air decontamination; Unidad para descontaminacion de aire

    Energy Technology Data Exchange (ETDEWEB)

    Mariano H, E

    1991-02-15

    To fulfill the applicable requirements of safety to the ventilation systems in nuclear facilities, it is necessary to make a cleaning of the air that hurtles to the atmosphere. For that which was designed and it manufactured an unit for decontamination of the air for the Pilot plant of production of Nuclear Fuel that this built one with national parts, uses Hepa national filters and the design can adapt for different dimensions of filters, also can be added a lodging for a prefilter or to adopt two Hepa filters. (Author)

  5. Psychiatric aspects of air pollution.

    Science.gov (United States)

    Lundberg, A

    1996-02-01

    Psychological and toxic effects of air pollution can lead to psychiatric symptoms, including anxiety and changes in mood, cognition, and behavior. Increased levels of some air pollutants are accompanied by an increase in psychiatric admissions and emergency calls and, in some studies, by changes in behavior and a reduction in psychological well-being. Numerous toxic pollutants interfere with the development and adult functioning of the nervous system. Manifestations are often insidious or delayed, but they can provide a more sensitive indicator of toxic effects than cancer rates or mortality data. Other medical effects of air pollution, such as asthma, can indirectly affect psychological health. The sick building syndrome and multiple chemical sensitivity are conditions with toxicologic and psychiatric aspects. Psychosocial stress can cause symptoms similar to those of organic mental disorders. Reactions to stress depend on cultural, individual, and situational variables. We must understand these factors to be able to alleviate and prevent the consequences of environmental trauma. Expanded research is recommended in three main areas: (1) how people perceive and cope with environmental health risks, (2) the effects of air pollution on behavior and neuropsychological functioning, and (3) neurotoxicologic evaluation of air pollutants with both behavioral and in vitro studies.

  6. [Air pollution and cardiovascular disease].

    Science.gov (United States)

    Haber, Guy; Witberg, Guy; Danenberg, Haim

    2007-10-01

    Cardiovascular atherothrombosis is the most common cause of death globally, with several well-known risk factors. Air pollution is a byproduct of fuel combustion by motor vehicles, power plants and industrial factories. It is composed of gases, fluids and particulate matter (PM) of different sizes, which include basic carbon, organic carbonic molecules and metals such as vanadium, nickel, zinc and iron. These particles are subdivided by their median size, a major contributing factor for their capability to enter the human body through the respiratory system. Most of the epidemiological studies have shown correlation between acute and long-term exposure to air pollution elements and cardiovascular morbidity in general, and angina pectoris and acute myocardial infarction specifically. Physiological studies have found different arrhythmias as the etiologic cause of cardiovascular morbidity and mortality following exposure to air pollution. A major finding was a decline in heart rate variability, a phenomenon known as endangering for cardiovascular morbidity and mortality, especially in patients after acute myocardial infarction. To date, several pathways have been proposed, including a hypercoagulable state following an inflammatory response, cardiac nervous autonomic disequilibrium, endothelial dysfunction with blood vessel contraction and direct toxic impact on cardiac muscle. Additional research is needed for clarifying the pathophysiological pathways by which air pollution affects the cardiovascular system. That might allow forthcoming with preventive measures and correct treatment, and hence a decrease in cardiovascular morbidity and mortality. Another important target is dose-outcome correlation curves for safety threshold calculation as a basis for air pollution regulations.

  7. Air protection strategy in Poland

    Energy Technology Data Exchange (ETDEWEB)

    Blaszczyk, B.

    1995-12-31

    Air quality is one of the basic factors determining the environmental quality and influencing the life conditions of people. There is a shortage of proper quality air in many regions of Poland. In consequence, and due to unhindered transport, air pollution is the direct cause of losses in the national economy (reduction of crops, losses in forestry, corrosion of buildings and constructions, worsening of people`s health). Poland is believed to be one of the most contaminated European countries. The reason for this, primarily, is the pollution concomitant with energy-generating fuel combustion; in our case it means the use of solid fuels: hard coal and lignite. This monocultural economy of energy generation is accompanied by low efficiency of energy use (high rates of energy loss from buildings, heat transmission pipelines, energy-consuming industrial processes). This inefficiency results in the unnecessary production of energy and pollution. Among other reasons, this results from the fact that in the past Poland did not sign any international agreements concerning the reduction of the emission of pollution. The activities aimes at air protection in Poland are conducted based on the Environmental Formation and Protection Act in effect since 1980 (with many further amendments) and the The Ecological Policy of the state (1991). The goals of the Polish air pollution reduction program for the period 1994-2000 are presented.

  8. [Microbial air purity in hospitals. Operating theatres with air conditioning system].

    Science.gov (United States)

    Krogulski, Adam; Szczotko, Maciej

    2010-01-01

    The aim of this study was to show the influence of air conditioning control for microbial contamination of air inside the operating theatres equipped with correctly working air-conditioning system. This work was based on the results of bacteria and fungi concentration in hospital air obtained since 2001. Assays of microbial air purity conducted on atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning systems worked correctly in every case. To show the problem of fluctuation of bacteria concentration more precisely, every sequences of single results from successive measure series were examined independently.

  9. Pigeons home faster through polluted air

    OpenAIRE

    Zhongqiu Li; Franck Courchamp; Daniel T. Blumstein

    2016-01-01

    Air pollution, especially haze pollution, is creating health issues for both humans and other animals. However, remarkably little is known about how animals behaviourally respond to air pollution. We used multiple linear regression to analyse 415 pigeon races in the North China Plain, an area with considerable air pollution, and found that while the proportion of pigeons successfully homed was not influenced by air pollution, pigeons homed faster when the air was especially polluted. Our resu...

  10. Considering Air Density in Wind Power Production

    CERN Document Server

    Farkas, Zénó

    2011-01-01

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  11. Commercial Air Carrier Vulnerabilities to Information Operations

    Science.gov (United States)

    2007-11-02

    GMO /ENS/02E-11 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio...AFIT/ GMO /ENS/02E-11 COMMERCIAL AIR CARRIER VULNERABILITIES TO INFORMATION OPERATIONS...networks that without them, “there is no water coming out of your tap; there is no electricity lighting your room; there is no food being transported to

  12. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat…

  13. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    Science.gov (United States)

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  14. 49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic brake subsystem. The following requirements apply to vehicles with air brake and...

  15. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate... holding of a drug product. (c) Air filtration systems, including prefilters and particulate matter...

  16. Picosecond laser filamentation in air

    CERN Document Server

    Schmitt-Sody, Andreas; Bergé, L; Skupin, S; Polynkin, Pavel

    2016-01-01

    The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear self-action effects and air ionization is investigated experimentally and numerically. The model used for numerical analysis is based on the nonlinear propagator for the optical field coupled with the rate equations for the production of various ionic species and plasma temperature. Our results show that the phenomenon of plasma-driven intensity clamping, which is paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions are limited and the pulse fluence is also clamped. The resulting unique feature of the picosecond filamentation regime is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for numerous applications.

  17. Steerable percussion air drilling system

    Energy Technology Data Exchange (ETDEWEB)

    Bui, H.D.; Meyers, J.A.; Yost, A.B. II

    1998-12-31

    By increasing penetration rates and bit life, especially in hard formations, the use of down-hole air hammers in the oil field has significantly reduced drilling costs in the Northeast US and West Texas. Unfortunately, drilling by this percussion method has been limited mostly to straight hole applications. This paper presents a new concept of a percussion drilling tool which performs both the function of a down-hole hammer as well as that of a down-hole motor. Such a drilling tool, being introduced here as Steerable Percussion Air Drilling System (SPADS), eliminates the necessity to rotate the drill string and, consequently, enables the use of down-hole air hammers to drill directional wells.

  18. High Energy Efficiency Air Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Edward McCullough; Patrick Dhooge; Jonathan Nimitz

    2003-12-31

    This project determined the performance of a new high efficiency refrigerant, Ikon B, in a residential air conditioner designed to use R-22. The refrigerant R-22, used in residential and small commercial air conditioners, is being phased out of production in developed countries beginning this year because of concerns regarding its ozone depletion potential. Although a replacement refrigerant, R-410A, is available, it operates at much higher pressure than R-22 and requires new equipment. R-22 air conditioners will continue to be in use for many years to come. Air conditioning is a large part of expensive summer peak power use in many parts of the U.S. Previous testing and computer simulations of Ikon B indicated that it would have 20 - 25% higher coefficient of performance (COP, the amount of cooling obtained per energy used) than R-22 in an air-cooled air conditioner. In this project, a typical new R-22 residential air conditioner was obtained, installed in a large environmental chamber, instrumented, and run both with its original charge of R-22 and then with Ikon B. In the environmental chamber, controlled temperature and humidity could be maintained to obtain repeatable and comparable energy use results. Tests with Ikon B included runs with and without a power controller, and an extended run for several months with subsequent analyses to check compatibility of Ikon B with the air conditioner materials and lubricant. Baseline energy use of the air conditioner with its original R-22 charge was measured at 90 deg F and 100 deg F. After changeover to Ikon B and a larger expansion orifice, energy use was measured at 90 deg F and 100 deg F. Ikon B proved to have about 19% higher COP at 90 deg F and about 26% higher COP at 100 deg F versus R-22. Ikon B had about 20% lower cooling capacity at 90 deg F and about 17% lower cooling capacity at 100 deg F versus R-22 in this system. All results over multiple runs were within 1% relative standard deviation (RSD). All of these

  19. Animal Welfare in Air Transport

    Directory of Open Access Journals (Sweden)

    Boris Popović

    2012-10-01

    Full Text Available Animal welfare is becoming an evermore-important factorfor air carriers from the economical viewpoint, due to its importantimpact on the carrier public image. High standard care hasto be taken of animals during transport in order to satisfy an importantsegment of airline customers, either the Business/Firstclass passengers travelling with pets, or influential shippers ofracing horses, dogs, Zoo species etc.Air transp011 of animals, disregarding other advantages,may pose a threat to their health and welfare being a significantmultifactorial stressor. Along with cardiovascular, endocrineand metabolic abe1mtions, it affects the immune response ofan animal and increases susceptibility to infection. Therefore,strict conditions for air transport of eve1y animal species havebeen imposed. Transport of only healthy animals is approved,as it is necessG/y to prevent the spread of disease during transportand to provide satisfactOJy environment for animals to betransported.

  20. Air pollution and allergic diseases

    Energy Technology Data Exchange (ETDEWEB)

    Ring, J.

    1987-03-13

    In the discussion on possible adverse effects of air pollution upon human health one has to distinguish between out-door and in-door environment. The most frequent pollutants in out-door air over industrialized areas are particulate substances, sulfur dioxide, nitrous oxide, carbonmonoxide, ozone and lead. Most of these substances have direct irritating effects on mucous surfaces. Hypersensitivity reactions have been described against sulfur dioxide and sulfites occurring as asthma, urticaria or anaphylactoid reactions. In-door air pollution is of much greater practical importance for a variety of diseases. Apart from physio-chemical irritants and microbial organisms leading to infections, organic allergens (e.g. house dust mites, moulds, animal epithelia) can induce a variety of allergic diseases via different pathomechanisms.

  1. Chern-Simons production during preheating in hybrid inflation models

    CERN Document Server

    García-Bellido, J; González-Arroyo, A; Garcia-Bellido, Juan; Perez, Margarita Garcia; Gonzalez-Arroyo, Antonio

    2004-01-01

    We study the onset of symmetry breaking after hybrid inflation in a model having the field content of the SU(2) gauge-scalar sector of the standard model, coupled to a singlet inflaton. This process is studied in (3+1)-dimensions in a fully non-perturbative way with the help of lattice techniques within the classical approximation. We focus on the role played by gauge fields and, in particular, on the generation of Chern-Simons number. Our results are shown to be insensitive to the various cut-offs introduced in our numerical approach. The spectra preserves a large hierarchy between long and short-wavelength modes during the whole period of symmetry breaking and Chern-Simons generation, confirming that the dynamics is driven by the low momentum sector of the theory. We establish that the Chern-Simons production mechanism is associated with local sphaleron-like structures. The corresponding sphaleron rates are of order 10^{-5} m^{-4}, which, within certain scenarios of electroweak baryogenesis and a (not unnat...

  2. Low SO2 Emission Preheaters for Cement Production

    DEFF Research Database (Denmark)

    Rasmussen, Martin Hagsted

    in this thesis has been to produce CaO with a large surface area in order to increase the absorption of SO2. For this purpose flash calcination of CaCO3, calcination under vacuum, calcination in a fixed bed and a fluid bed has been tested between 650 °C and 850 °C. The results showed that flash calcination...... reaction between SO2 and CaO is so fast that the observed rates exclusively are determined by solid state diffusion in the product layer of the non-porous CaO grains. An activation energy of 115 kJ/mole was found to fit all CaO sources very well, even though data fitting by the least sum of squares method...

  3. A stochastic background of gravitational waves from hybrid preheating

    CERN Document Server

    García-Bellido, J; Garcia-Bellido, Juan; Figueroa, Daniel G.

    2006-01-01

    The process of reheating the universe after hybrid inflation is extremely violent. It proceeds through the nucleation and subsequent collision of large concentrations of energy density in bubble-like structures, which generate a significant fraction of energy in the form of gravitational waves. We study the power spectrum of the stochastic background of gravitational waves produced at reheating after hybrid inflation. We find that the amplitude could be significant for high-scale models, although the typical frequencies are well beyond what could be reached by planned gravitational wave observatories like LIGO, LISA or BBO. On the other hand, low-scale models could still produce a detectable stochastic background at frequencies accesible to those detectors. The discovery of such a background would open a new window into the very early universe.

  4. Preheating in an Asymptotically Safe Quantum Field Theory

    CERN Document Server

    Svendsen, Ole; Brandenberger, Robert

    2016-01-01

    We consider reheating in a class of asymptotically safe quantum field theories recently studied in \\cite{Litim:2014uca, Litim:2015iea}. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period of reheating. Since the models contain many scalar fields which are intrinsically coupled to the inflaton there is the possibility of parametric resonance instability in the production of these fields, and the danger that the induced curvature fluctuations will become too large. Here we show that the parametric instability indeed arises, and that hence the energy transfer from the inflaton condensate to fluctuating fields is rapid. Demanding that the curvature fluctuations induced by the parametrically amplified entropy modes do not exceed the upper observational bounds puts a lower bound on the number of fields which the model of Ref.~\\cite{Litim:2014uca, Litim:2015iea} must contain. This bound also depends on the total number of e-foldings of the inflationary phase.

  5. Air quality management planning (AQMP

    Directory of Open Access Journals (Sweden)

    Sivertsen Bjarne

    2012-01-01

    Full Text Available In most urban areas of the world, particulate matter (PM levels pose severe problems, addressed in several policy areas (air quality, climate change, and human health. PM presents multiple challenges due to the multitude of its sources, spanning many sectors of economic activity as well as nature, and due to the complexity of atmospheric processes involved in its transport and secondary formation. For the authorities, the goal is to assure minimal impacts of atmospheric PM levels, in practice represented by compliance with existing regulations and standards. This may be achieved through an air quality management plan (AQMP. In Northern America and in parts of Europe, comprehensive research programs have guided development of AQMP over the last forty years. This cumulated experience can be utilized by others who face the same problems, but have yet to develop their own substantial research base. The main purpose of the AQMP development process is to establish an effective and sound basis for planning and management of air quality in a selected area. This type of planning will ensure that significant sources of impacts are identified and controlled in a most cost-effective manner. The choice of tools, methods and input information is often dictated by their availability, and should be evaluated against current best practices. Important elements of the AQMP are the identification of sources and development of a complete emission inventory, the development and operation of an air quality monitoring programme, and the development and application of atmospheric dispersion models. Major task is to collect the necessary input data. The development of the AQMP will take into account: - Air Quality Management System (AQMS requirements; - Operational and functional structure requirements; - Source identification through emission inventories; - Source reduction alternatives, which may be implemented; - Mechanisms for facilitating interdepartmental

  6. Thermodynamic properties of sea air

    Directory of Open Access Journals (Sweden)

    R. Feistel

    2010-02-01

    Full Text Available Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere-ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS, and have been adopted in 2009 for oceanography by IOC/UNESCO.

    In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as "sea air" here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well.

    The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.

  7. Thermodynamic properties of sea air

    Directory of Open Access Journals (Sweden)

    R. Feistel

    2009-10-01

    Full Text Available Very accurate thermodynamic potential functions are available for fluid water, ice, seawater and humid air covering wide ranges of temperature and pressure conditions. They permit the consistent computation of all equilibrium properties as, for example, required for coupled atmosphere–ocean models or the analysis of observational or experimental data. With the exception of humid air, these potential functions are already formulated as international standards released by the International Association for the Properties of Water and Steam (IAPWS, and have been adopted in 2009 for oceanography by IOC/UNESCO.

    In this paper, we derive a collection of formulas for important quantities expressed in terms of the thermodynamic potentials, valid for typical phase transitions and composite systems of humid air and water/ice/seawater. Particular attention is given to equilibria between seawater and humid air, referred to as ''sea air'' here. In a related initiative, these formulas will soon be implemented in a source-code library for easy practical use. The library is primarily aimed at oceanographic applications but will be relevant to air-sea interaction and meteorology as well.

    The formulas provided are valid for any consistent set of suitable thermodynamic potential functions. Here we adopt potential functions from previous publications in which they are constructed from theoretical laws and empirical data; they are briefly summarized in the appendix. The formulas make use of the full accuracy of these thermodynamic potentials, without additional approximations or empirical coefficients. They are expressed in the temperature scale ITS-90 and the 2008 Reference-Composition Salinity Scale.

  8. Flow in air conditioned rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    1974-01-01

    of the flow equations is demonstrated and the flow in air conditioned rooms in case of steady two dimensional flow is predi cted. Compari son with measured results is shown i n the case of small Archimedes numbers, and predictions are shown at high Archimedes numbers. A numerical prediction of f low and heat......Flow in air conditioned r ooms is examined by means of model experiments . The different gearnetries giving unsteady, steady three- dimensional and steady twodimensional flow are determined . Velacity profiles and temperature profiles are measured in some of the geometries. A numerical solution...

  9. When water molecules meet air

    OpenAIRE

    Hsie, Cho-Shuen; Campen, R. Kramer; Verde, Ana Vila; Bolhuis, Peter; Nienhuys, Han-Kwang; Bonn, Mischa

    2012-01-01

    About 70% of our planet is covered in water. Most of that water exists as water in the bulk – the neighbors of water molecules are other water molecules – and only a small fraction of molecules are at the air-water interface. Despite the small relative abundance of interfacial water, it is of the utmost importance: it governs the chemistry involving the surface of oceans and seawater aerosols, or the small water droplets forming clouds. Reactions at the air-water interface are directly releva...

  10. 高温低氧燃烧技术及其高效低污染特性分析%High temperature air combustion and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    蒋绍坚; 艾元方; 彭好义; 萧泽强; 周孑民; 汪洋洋; 熊家政

    2000-01-01

    研究了一种高温低氧燃烧新技术,即采用蓄热室,预热助燃剂使其温度达到800℃以上;采用分级燃烧及炉内部分烟气回流的方法,使燃烧区氧体积分数降低至15%以下.分析结果表明:该燃烧技术具有显著的节能、低污染特性,与未采取任何废热回收措施的传统燃烧技术相比,可实现节能60%以上,CO2排放量减少60%以上,NOx排放浓度低于30~50g/t.%The high temperature air combustion technology is introduced in this paper. The air is preheated over 800℃by regenerator and oxygen concentration is decreased to less than 15% by graded combustion and a part of exhaust gas isrecycled in furnace. Analyses show that, the technology can save energy efficiently up to 60% and reduce pollution. Forexample, the discharge of CO2 can be reduced by 60%, and the discharging concentration of NOx is less than 30~50 g/t compared with traditional combustion technology without provision of any waste heat recovery means.

  11. Multizone Age-of-Air Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.

    2007-07-01

    Age of air is a technique for evaluating ventilation that has been actively used for over 20 years. Age of air quantifies the time it takes for outdoor air to reach a particular location or zone within then indoor environment. Age of air is often also used to quantify the ventilation effectiveness with respect to indoor air quality. In a purely single zone situation this use of age of air is straightforward, but application of age of air techniques in the general multizone environment has not been fully developed. This article looks at expanding those single-zone techniques to the more complicated environment of multizone buildings and in doing so develops further the general concept of age of air. The results of this analysis shows that the nominal age of air as often used cannot be directly used for determining ventilation effectiveness unless specific assumptions are made regarding source distributions.

  12. 77 FR 52277 - Approval of Air Quality Implementation Plans; California; South Coast Air Quality Management...

    Science.gov (United States)

    2012-08-29

    ... submitted for the South Coast Air Quality Management District (District) portion of the California State... AGENCY 40 CFR Part 52 Approval of Air Quality Implementation Plans; California; South Coast Air Quality Management District; Prevention of Significant Deterioration; Greenhouse Gases AGENCY:...

  13. Aerometric Information Retrieval System/AIRS Facility Subsystem (AIRS/AFS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Aerometric Information Retrieval System/AIRS Facility Subsystem (AIRS/AFS) is a database that provides information on air releases from various stationary...

  14. 78 FR 53270 - Revision of Air Quality Implementation Plan; California; Sacramento Metropolitan Air Quality...

    Science.gov (United States)

    2013-08-29

    ... AGENCY 40 CFR Part 52 Revision of Air Quality Implementation Plan; California; Sacramento Metropolitan Air Quality Management District; Stationary Source Permits AGENCY: Environmental Protection Agency... permitting rules submitted by California as a revision to the Sacramento Metropolitan Air Quality...

  15. 78 FR 10589 - Revision of Air Quality Implementation Plan; California; Sacramento Metropolitan Air Quality...

    Science.gov (United States)

    2013-02-14

    ... AGENCY 40 CFR Part 52 Revision of Air Quality Implementation Plan; California; Sacramento Metropolitan Air Quality Management District; Stationary Source Permits AGENCY: Environmental Protection Agency... by California as a revision to the Sacramento Metropolitan Air Quality Management District (SMAQMD...

  16. Operating experiences with rotary air-to-air heat exchangers: hospitals, schools, nursing homes, swimming pools

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.J.

    1976-01-01

    Systems utilizing rotary air-to-air heat exchangers are discussed. Basic considerations of use (fresh air requirements, system configurations, cost considerations), typical system layout/design considerations, and operating observations by engineers, staff and maintenance personnel are described.

  17. Antibubbles and fine cylindrical sheets of air

    KAUST Repository

    Beilharz, D.

    2015-08-14

    Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air layers which can wrap around the entire drop to form repeatable antibubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread reaching all the way to the pinch-off nozzle. The air sheet can also wrap around this thread and remain stable over an extended period of time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these thin cylindrical air sheets is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer. We use interferometry to measure the air-layer thickness versus depth along the cylindrical air sheet and around the drop. The air film is thickest above the equator of the drop, but thinner below the drop and up along the air cylinder. Based on microbubble volumes, the thickness of the cylindrical air layer becomes less than 100 nm before it ruptures.

  18. Control and prevention of surge in axial primary air fan%轴流式一次风机喘振的控制与预防

    Institute of Scientific and Technical Information of China (English)

    冯宗田; 曹磊; 蔺晶

    2011-01-01

    According to the surging in the axial primary air fan frequently in recent years, based on analysis of the mechanism and reason,lots of exploration and practice from several aspects were made, such as adjusting the operation, eliminating the defects and maintaining the equipments. Some improving methods were carried out. The pressure of the hot primary air main pipe and the change rate of unit load were decreased. The coal pulverizing system was operated carefully especially for start-stop. The treatment of the wind channel and the soot blowing in the air preheater were improved and the air fan was operated in the stable region. Practice proves that the effects are prominent by improving elaboration of adjusting the operation and enhancing equipment maintenance. By taking preventive measures, the frequency of the surge was reduced evidently, the credibility of the primary air fan was enhanced and the efficiency of the power plant was improved observably.%针对近年来频繁发生的一次风机喘振现象,深入分析了喘振发生的机理和原因,在运行调整和设备消缺维护等方面进行了大量探索和实践,改进措施包括:降低热一次风母管压力和机组负荷增减速率;谨慎进行制粉系统启停操作;加强烟风道治理和空预器吹灰;尽量使风机工作压力避开不稳定区域.运行实践证明,通过提高运行调整精细化程度、加大设备维护治理后效果显著,采取相关防范措施后一次风机喘振次数明显减少,有益于提高一次风机运行可靠性和发电厂效益.

  19. Air Power in Irregular Warfare

    Science.gov (United States)

    2012-12-01

    bombardment attacks with fighter offense for the control of the air.”57 Douhet commonly bucked the theory of fighter offense, relying solely on “a...morale booster as well. Now patrols could cut a landing zone with chain saws and explosives to receive a medevac chopper rather than face an extended

  20. New concepts in air abrasion.

    Science.gov (United States)

    Porth, R N

    1998-03-01

    There is no doubt that air abrasion is going to be part of the millennial shift in dentistry away from traditional treatment modalities. With the change in incidence and morphology of caries as a result of the hardening effect of fluoride on enamel, this ability to remove only decayed areas and permanently seal the less susceptible areas becomes increasingly desirable.