WorldWideScience

Sample records for preheated secondary air

  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. Adaptive preheating duration control for low-power ambient air quality sensor networks.

    Science.gov (United States)

    Baek, Yoonchul; Atiq, Mahin K; Kim, Hyung Seok

    2014-03-20

    Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback-large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC) method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  4. Adaptive Preheating Duration Control for Low-Power Ambient Air Quality Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yoonchul Baek

    2014-03-01

    Full Text Available Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback—large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  5. 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.

  6. 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.

  7. 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.)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Design of a DCS Based Model for Continuous Leakage Monitoring System of Rotary Air Preheater of a Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    Madan BHOWMICK

    2011-01-01

    Full Text Available The leakage in rotary air preheater makes a considerable contribution to the reduced overall efficiency of fossil-fuel-fired thermal power plants and increase the effect on environment. Since it is normal phenomenon, continuous monitoring of leakage is generally omitted in most power plants. But for accurate analysis of the operation of the thermal power plant, this leakage monitoring plays a vital role. In the present paper, design of a DCS based model for continuous leakages monitoring of rotary air preheater has been described. In the proposed model, the existing DCS based instrumentation system has been modified and online leakage monitoring system has been developed. This model has been installed in a captive power plant with high capacity boilers and very much satisfactory operation of this system has been observed. The observed online data along with their analysis results are presented in this paper.

  17. 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。

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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。

  3. 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。

  4. 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...

  5. 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 .

  6. Preheating after modular inflation

    Science.gov (United States)

    Barnaby, Neil; Bond, J. Richard; Huang, Zhiqi; Kofman, Lev

    2009-12-01

    We study (p)reheating in modular (closed string) inflationary scenarios, with a special emphasis on Kähler moduli/Roulette models. It is usually assumed that reheating in such models occurs through perturbative decays. However, we find that there are very strong non-perturbative preheating decay channels related to the particular shape of the inflaton potential (which is highly nonlinear and has a very steep minimum). Preheating after modular inflation, proceeding through a combination of tachyonic instability and broad-band parametric resonance, is perhaps the most violent example of preheating after inflation known in the literature. Further, we consider the subsequent transfer of energy to the standard model sector in scenarios where the standard model particles are confined to a D7-brane wrapping the inflationary blow-up cycle of the compactification manifold or, more interestingly, a non-inflationary blow-up cycle. We explicitly identify the decay channels of the inflaton in these two scenarios. We also consider the case where the inflationary cycle shrinks to the string scale at the end of inflation; here a field theoretical treatment of reheating is insufficient and one must turn instead to a stringy description. We estimate the decay rate of the inflaton and the reheat temperature for various scenarios.

  7. 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.

  8. 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.

  9. Influence of the pre-ionization background and simulation of the optical emission of a streamer discharge in preheated air at atmospheric pressure between two point electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bourdon, A; Bonaventura, Z [Ecole Centrale Paris, EM2C Laboratory, UPR CNRS 288, Grande voie des vignes, 92295 Chatenay-Malabry Cedex (France); Celestin, S, E-mail: anne.bourdon@em2c.ecp.f [Communications and Space Sciences Laboratory, Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-06-15

    This paper presents simulations of positive and negative streamers propagating between two point electrodes in preheated air at atmospheric pressure. As many discharges have occurred before the simulated one, seed charges are taken into account in the interelectrode gap. First, for a pre-ionization background of 10{sup 9} cm{sup -3}, we have studied the influence of the data set used for transport parameters and reaction rates for air on the simulation results. We have compared results obtained in 1997 using input parameters from Morrow and Lowke and from Kulikovsky. Deviations as large as 20% of streamer characteristics (i.e. electric field in the streamer head and body, streamer velocity, streamer radius, streamer electron density) have been observed for this point-to-point configuration. Second, we have studied the influence of the pulsed voltage frequency on the discharge structure. For the studied discharge regime, a change in the applied voltage frequency corresponds to a change in the pre-ionization background. In this work, we have considered a wide range of pre-ionization values from 10{sup 4} and up to 10{sup 9} cm{sup -3}. We have noted that the value of the pre-ionization background has a small influence on the electron density, electric field and location of the negative streamer head. Conversely, it has a significant influence on the positive streamer characteristics. Finally, we have compared instantaneous and time-averaged optical emissions of the three band systems of N{sub 2} and N{sub 2}{sup +} (1PN{sub 2}, 2PN{sub 2} and 1NN{sub 2}{sup +}) during the discharge propagation. We have shown that the emission of the 2PN{sub 2} is the strongest of the three bands, in agreement with experimental observations. It is interesting to note that even with a short time averaging of a few nanoseconds, which corresponds to currently used instruments, the structure of the time-averaged emission of the 2PN{sub 2} is different from the instantaneous one and shows

  10. 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.

  11. 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.

  12. 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.

  13. 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。

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. Cleaning products and air fresheners: exposure to primary and secondary air pollutants

    DEFF Research Database (Denmark)

    Nazaroff, W.; Weschler, Charles J.

    2004-01-01

    . More than two dozen research articles present evidence of adverse health effects from inhalation exposure associated with cleaning or cleaning products. Exposure to primary and secondary pollutants depends on the complex interplay of many sets of factors and processes, including cleaning product...... by the US federal government as hazardous air pollutants (HAPs). California's Proposition 65 list of species recognized as carcinogens or reproductive toxicants also includes constituents of certain cleaning products and air fresheners. In addition, many cleaning agents and air fresheners contain chemicals...... that can react with other air contaminants to yield potentially harmful secondary products. For example, terpenes can react rapidly with ozone in indoor air generating many secondary pollutants, including TACs such as formaldehyde. Furthermore, ozone-terpene reactions produce the hydroxyl radical, which...

  20. 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 ...

  1. 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...

  2. 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)

  3. 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.

  4. 40 CFR 50.16 - National primary and secondary ambient air quality standards for lead.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for lead. 50.16 Section 50.16 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.16 National primary and secondary ambient air quality standards for lead. (a) The national primary...

  5. 40 CFR 50.12 - National primary and secondary ambient air quality standards for lead.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for lead. 50.12 Section 50.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.12 National primary and secondary ambient air quality standards for lead. (a) National primary and...

  6. 40 CFR 50.6 - National primary and secondary ambient air quality standards for PM10.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for PM10. 50.6 Section 50.6 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.6 National primary and secondary ambient air quality standards for PM10. (a) The level of the...

  7. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.15 National primary and secondary ambient air quality standards for ozone. (a) The level of...

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. 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...

  13. 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...

  14. Pre-heating mitigates composite degradation

    Directory of Open Access Journals (Sweden)

    Jessika Calixto da SILVA

    2015-12-01

    Full Text Available ABSTRACT 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 (p<0.05. After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05. There was a lower penetration of silver in pre-heated specimens (p<0.05. Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  15. 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.

  16. 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%.

  17. 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...

  18. Production and characterization of bi-functional cathodes for secondary zinc-air batteries

    OpenAIRE

    Kube, Alexander; Wittmaier, Dennis; Wagner, Norbert; Prof. Friedrich, K. Andreas

    2016-01-01

    One of the major drawbacks for today’s energy market of renewable energy production is that there is no cost efficient possibility to store produced energy for times when renewable energy production is less then energy consumption. The EU funded Project “ZAS – Zinc Air Secondary batteries based on innovative nanotechnology for efficient energy storage” has the goal to overcome this drawback by developing a new generation of secondary zinc-air batteries. Zinc based metal-air batteries have ...

  19. 2000 NASA Seal/Secondary Air System Workshop. Volume 1

    Science.gov (United States)

    Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

    2001-01-01

    The 2000 NASA Seal/Secondary Air System Workshop covered four main areas: (1) overviews of NASA-sponsored Ultra-Efficient Engine Technology (UEET) and Access to Space Programs, with emphasis on program goals and seal needs; (2) review of turbine engine seal issues from the perspective of end users such as United Airlines; (3) reviews of sealing concepts, test results, experimental facilities, and numerical predictions; and (4) reviews of material development programs relevant to advanced seals development. The NASA UEET overview illustrates for the reader the importance of advanced technologies, including seals, in meeting future engine system efficiency and emission goals. GE, Pratt & Whitney, and Honeywell presented advanced seal development work being performed within their organizations. The NASA-funded GE/Stein Seal team has successfully demonstrated a large (3-ft. diam) aspirating seal that can withstand all anticipated pressures, speeds, and rotor runouts anticipated for a GE90 L.P. turbine balance piston location. GE/Stein Seal are fabricating a full-scale seal to be tested in a GE-90 ground test engine in early 2002. Pratt & Whitney and Stein Seal are investigating carbon seals to accommodate large radial movements anticipated in future geared-fan gearbox locations. Honeywell presented a finger seal design being considered for a high-temperature static combustor location incorporating ceramic finger elements. Successful demonstration of the braided carbon rope thermal barriers to extreme temperatures (5500 F) for short durations provide a new form of very high temperature thermal barrier for future Shuttle solid rocket motor nozzle joints. The X-37, X-38, and future highly reusable launch vehicles pose challenging control surface seal demands that require new seal concepts made from emerging high temperature ceramics and other materials.

  20. 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.

  1. Refrigeration, Heating & Air Conditioning. Post Secondary Curriculum Guide.

    Science.gov (United States)

    Garrison, Joe C.; And Others

    This curriculum guide was designed for use in postsecondary refrigeration, heating and air conditioning education programs in Georgia. Its purpose is to provide for the development of entry level skills in refrigeration, heating, and air conditioning in the areas of air conditioning knowledge, theoretical structure, tool usage, diagnostic ability,…

  2. 76 FR 48073 - Public Hearing for Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and...

    Science.gov (United States)

    2011-08-08

    ... AGENCY 40 CFR Part 50 RIN 2060-AO72 Public Hearing for Secondary National Ambient Air Quality Standards... titled ``Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur'' which was... ``Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur'' proposed rule should...

  3. 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.

  4. 40 CFR 50.7 - National primary and secondary ambient air quality standards for PM2.5.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for PM2.5. 50.7 Section 50.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.7 National primary and secondary ambient air quality standards for PM2.5. (a) The national primary...

  5. 40 CFR 50.13 - National primary and secondary ambient air quality standards for PM2.5.

    Science.gov (United States)

    2010-07-01

    ... air quality standards for PM2.5. 50.13 Section 50.13 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.13 National primary and secondary ambient air quality standards for PM2.5. (a) The national...

  6. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Science.gov (United States)

    2010-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level...

  7. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Science.gov (United States)

    2010-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level...

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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...

  13. 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...

  14. Aggregating Secondary Source Data for Air Cargo Prescreening Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to improve the effectiveness of air cargo prescreening by enabling background knowledge about companies and products to be used for threat assessment. The...

  15. 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.

  16. Development of a novel metal hydride-air secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Gamburzev, S.; Zhang, W.; Velev, O.A.; Srinivasan, S.; Appleby, A.J. [Texas A and M University, College Station (United States). Center for Electrochemical Systems and Hydrogen Research; Visintin, A. [Universidad Nacional de La Plata (Argentina). Insituto Nacional de Investigaciones Fisicoquimica Teoricas y Applicadas

    1998-05-01

    A laboratory metal hydride/air cell was evaluated. Charging was via a bifunctional air gas-diffusion electrode. Mixed nickel and cobalt oxides, supported on carbon black and activated carbon, were used as catalysts in this electrode. At 30 mA cm{sup -2} in 6 M KOH, the air electrode potentials were -0.2 V (oxygen reduction) and +0.65 V (oxygen evolution) vs Hg/HgO. The laboratory cell was cycled for 50 cycles at the C/2 rate (10 mA cm{sup -2}). The average discharge/charge voltages of the cell were 0.65 and 1.6 V, respectively. The initial capacity of the metal hydride electrode decreased by about 15% after 50 cycles. (author)

  17. 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.

  18. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Science.gov (United States)

    2010-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.11 National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of...

  19. 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)

  20. 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

  1. Air leak: An unusual manifestation of organizing pneumonia secondary to bleomycin

    Science.gov (United States)

    Namitha, R; Nimisha, KP; Yusuf, Nasser; Rauf, CP

    2017-01-01

    Organizing pneumonia (OP) is a less common interstitial lung disease with varying clinical picture. The development of pulmonary air leak in a case of OP is an extremely rare complication. Here, we report the case of a 46-year-old female with carcinoma ovary, postchemotherapy who developed respiratory distress with pneumomediastinum, and subcutaneous emphysema. Lung biopsy showed evidence of OP. This turned out to be a rare case of OP, secondary to bleomycin chemotherapy, presenting with pulmonary air leak. PMID:28360468

  2. Experimental data and boundary conditions for a Double - Skin Facade building in preheating mode

    DEFF Research Database (Denmark)

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

    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......’. 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...

  3. 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.

  4. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    DEFF Research Database (Denmark)

    Weschler, Charles J.; Shields, H.C.

    2003-01-01

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution...

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. Transboundary Secondary Organic Aerosol in the Urban Air of Fukuoka, Japan

    CERN Document Server

    Irei, Satoshi; Hara, Keiichiro; Hayashi, Masahiko

    2016-01-01

    Studies providing quantitative information regarding secondary organic aerosol (SOA), the least understood subject in atmospheric chemistry, are important to evaluating secondary transboundary pollution. To obtain quantitative information of long-range transported SOA in the air of Fukuoka, we conducted simultaneous field studies during December 2010 and March 2012 at a rural site in northern Kyushu and at an urban site in Fukuoka City. During the studies, we collected airborne particulate matter (PM) on filters and extracted the low-volatile water soluble organic carbon (LV-WSOC) component, which is possibly dominated by SOA, from the filter samples and analyzed it to determine the carbon concentration and stable carbon isotope ratio. Under the assumption that the LV-WSOC at Fukuoka had both transboundary and local origins, we then applied end-member mixing analysis (EMMA) to the stable carbon isotope ratio data from both sites to estimate the fraction of LV-WSOCs from these origins in the Fukuoka air. Indep...

  10. 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.

  11. 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...

  12. 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.

  13. Indoor secondary pollutants from cleaning product and air freshener use in the presence of ozone

    DEFF Research Database (Denmark)

    Singer, B.C.; Coleman, B.K.; Destaillats, H.

    2006-01-01

    This study investigated the formation of secondary pollutants resulting from household product use in the presence of ozone. Experiments were conducted in a 50-m(3) chamber simulating a residential room. The chamber was operated at conditions relevant to US residences in polluted areas during warm......-oil air freshener (AFR) was operated for several days. Cleaning products were applied realistically with quantities scaled to simulate residential use rates. Concentrations of organic gases and secondary organic aerosol from the terpene-containing consumer products were measured with and without ozone...... than 100 mu g m(-3)) in some experiments. Ozone consumption and elevated hydroxyl radical concentrations persisted for 10-12 h following brief cleaning events, indicating that secondary pollutant production can persist for extended periods. (c) 2006 Elsevier Ltd. All rights reserved....

  14. 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.

  15. Impact of secondary inorganic aerosol and road traffic at a suburban air quality monitoring station.

    Science.gov (United States)

    Megido, L; Negral, L; Castrillón, L; Fernández-Nava, Y; Suárez-Peña, B; Marañón, E

    2017-03-15

    PM10 from a suburban site in the northwest of Spain was assessed using data from chemical determinations, meteorological parameters, aerosol maps and five-day back trajectories of air masses. Temporal variations in the chemical composition of PM10 were subsequently related to stationary/mobile local sources and long-range transport stemming from Europe and North Africa. The presence of secondary inorganic species (sulphates, nitrates and ammonium) in airborne particulate matter constituted one of the main focuses of this study. These chemical species formed 16.5% of PM10 on average, in line with other suburban background sites in Europe. However, a maximum of 47.8% of PM10 were recorded after several days under the influence of European air masses. Furthermore, the highest values of these three chemical species coincided with episodes of poor air circulation and influxes of air masses from Europe. The relationship between SO4(2-) and NH4(+) (R(2) = 0.57, p-valueair quality at the suburban site under study, with important apportionments of particulate matter coming from road traffic and as consequence of releasing precursor gases of secondary particles to the atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Final Air Toxics Standards for Clay Ceramics Manufacturing, Glass Manufacturing, and Secondary Nonferrous Metals Processing Area Sources Fact Sheet

    Science.gov (United States)

    This page contains a December 2007 fact sheet with information regarding the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Clay Ceramics Manufacturing, Glass Manufacturing, and Secondary Nonferrous Metals Processing Area Sources

  17. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... STANDARDS Pt. 50, App. P Appendix P to Part 50—Interpretation of the Primary and Secondary National...

  18. Secondary organic aerosol formation from photo-oxidation of toluene with NOx and SO2: Chamber simulation with purified air versus urban ambient air as matrix

    Science.gov (United States)

    Deng, Wei; Liu, Tengyu; Zhang, Yanli; Situ, Shuping; Hu, Qihou; He, Quanfu; Zhang, Zhou; Lü, Sujun; Bi, Xinhui; Wang, Xuemei; Boreave, Antoinette; George, Christian; Ding, Xiang; Wang, Xinming

    2017-02-01

    Chamber studies on the formation of secondary aerosols are mostly performed with purified air as matrix, it is of wide concern in what extent they might be different from the situations in ambient air, where a variety of gaseous and particulate components preexist. Here we compared the photo-oxidation of "toluene + NOx + SO2" combinations in a smog chamber in real urban ambient air matrix with that in purified air matrix. The secondary organic aerosols (SOA) mass concentrations and yields from toluene in the ambient air matrix, after subtracted ambient air background primary and secondary organic aerosols, were 9.0-34.0 and 5.6-12.9 times, respectively, greater than those in purified air matrix. Both homogeneous and heterogeneous oxidation of SO2 were enhanced in ambient air matrix experiments with observed 2.0-7.5 times higher SO2 degradation rates and 2.6-6.8 times faster sulfate formation than that in purified air matrix, resulting in higher in-situ particle acidity and consequently promoting acid-catalyzed SOA formation. In the ambient air experiments although averaged OH radical levels were elevated probably due to heterogeneous formation of OH on particle surface and/or ozonolysis of alkenes, non-OH oxidation pathways of SO2 became even more dominating. Under the same organic aerosol mass concentration, the SOA yields of toluene in purified air matrix experiments matched very well with the two-product model curve by Ng et al. (2007), yet the yields in ambient air on average was over two times larger. The results however were much near the best fit curve by Hildebrandt et al. (2009) with the volatility basis set (VBS) approach.

  19. 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.

  20. Analytical dispersion model for the chain of primary and secondary air pollutants released from point source

    Science.gov (United States)

    Juodis, Laurynas; Filistovič, Vitold; Maceika, Evaldas; Remeikis, Vidmantas

    2016-03-01

    An analytical model for dispersion of air pollutants released from a point source forming a secondary pollutant (e.g. chemical transformation or parent-daughter radionuclide chain) is formulated considering the constant wind speed and eddy diffusivities as an explicit function of downwind distance from the source in Cauchy (reflection-deposition type) boundary conditions. The dispersion of pollutants has been investigated by using the Gaussian plume dispersion parameters σy and σz instead of the diffusivity parameters Ky and Kz. For primary pollutant it was proposed to use the derived dry deposition factor instead of the source depletion alternative. An analytical solution for steady-state two-dimensional pollutant transport in the atmosphere is presented. Derived formulas include dependency from effective release height, gravitational and dry deposition velocities of primary and secondary pollutants, advection, surface roughness length and empirical dispersion parameters σy and σz. Demonstration of analytical solution application is provided by calculation of 135Xe and 135C air activity concentrations and the applicability of the model for the solution of atmospheric pollution transport problems.

  1. 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.

  2. 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.

  3. Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

    Directory of Open Access Journals (Sweden)

    T. Wang

    2010-08-01

    Full Text Available This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NOx and volatile organic compounds (VOCs at an urban site dropped by 25% and 20–45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions. A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34–88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv, indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO2, total sulfur (SO2+PM2.5 sulfate, carbon monoxide (CO, reactive aromatics (toluene and xylenes sharply decreased (by 8–64% in 2008, but no significant changes were observed for the concentrations of

  4. Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

    Science.gov (United States)

    Wang, T.; Nie, W.; Gao, J.; Xue, L. K.; Gao, X. M.; Wang, X. F.; Qiu, J.; Poon, C. N.; Meinardi, S.; Blake, D.; Wang, S. L.; Ding, A. J.; Chai, F. H.; Zhang, Q. Z.; Wang, W. X.

    2010-08-01

    This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NOx) and volatile organic compounds (VOCs) at an urban site dropped by 25% and 20-45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants) improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions). A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34-88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv), indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO2), total sulfur (SO2+PM2.5 sulfate), carbon monoxide (CO), reactive aromatics (toluene and xylenes) sharply decreased (by 8-64%) in 2008, but no significant changes were observed for the concentrations of PM2.5, fine sulfate, total odd reactive nitrogen (NOy), and longer

  5. Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

    Directory of Open Access Journals (Sweden)

    T. Wang

    2010-05-01

    Full Text Available This paper presents the first results of the atmospheric measurements of trace gases and aerosols at three surface sites in and around Beijing before and during the 2008 Olympics. We focus on secondary pollutants including ozone, fine sulfate and nitrate, and the contribution of regional sources in summer 2008. The results reveal different responses of secondary pollutants to the control measures from primary pollutants. Ambient concentrations of vehicle-related nitrogen oxides (NOx and volatile organic compounds (VOCs at an urban site dropped by 25% and 20–45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions. A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed 34%–88% to the peak ozone concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv, indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO2, total sulfur (SO2+PM2.5 sulfate, carbon monoxide (CO, reactive aromatics (toluene and xylenes sharply decreased (by 8–64% in 2008, but no significant changes were observed for the concentrations of PM2.5, fine sulfate, total odd reactive nitrogen (NOy, and longer

  6. 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.

  7. Secondary effects of urban heat island mitigation measures on air quality

    Science.gov (United States)

    Fallmann, Joachim; Forkel, Renate; Emeis, Stefan

    2016-01-01

    This study presents numerical simulations analysing the effect of urban heat island (UHI) mitigation measures on the chemical composition of the urban atmosphere. The mesoscale chemical transport model WRF-Chem is used to investigate the impact of urban greening and highly reflective surfaces on the concentrations of primary (CO, NO) as well as secondary pollutants (O3) inside the urban canopy. In order to account for the sub-grid scale heterogeneity of urban areas, a multi-layer urban canopy model is coupled to WRF-Chem. Using this canopy model at its full extend requires the introduction of several urban land use classes in WRF-Chem. The urban area of Stuttgart serves as a test bed for the modelling of a case scenario of the 2003 European Heat Wave. The selected mitigation measures are able to reduce the urban temperature by about 1 K and the mean ozone concentration by 5-8%. Model results however document also negative secondary effects on urban air quality, which are closely related to a decrease of vertical mixing in the urban boundary layer. An increase of primary pollutants NO and CO by 5-25% can be observed. In addition, highly reflective surfaces can increase peak ozone concentration by up to 12% due to a high intensity of reflected shortwave radiation accelerating photochemical reactions.

  8. A computationally-efficient secondary organic aerosol module for three-dimensional air quality models

    Science.gov (United States)

    Liu, P.; Zhang, Y.

    2008-07-01

    Accurately simulating secondary organic aerosols (SOA) in three-dimensional (3-D) air quality models is challenging due to the complexity of the physics and chemistry involved and the high computational demand required. A computationally-efficient yet accurate SOA module is necessary in 3-D applications for long-term simulations and real-time air quality forecasting. A coupled gas and aerosol box model (i.e., 0-D CMAQ-MADRID 2) is used to optimize relevant processes in order to develop such a SOA module. Solving the partitioning equations for condensable volatile organic compounds (VOCs) and calculating their activity coefficients in the multicomponent mixtures are identified to be the most computationally-expensive processes. The two processes can be speeded up by relaxing the error tolerance levels and reducing the maximum number of iterations of the numerical solver for the partitioning equations for organic species; conditionally activating organic-inorganic interactions; and parameterizing the calculation of activity coefficients for organic mixtures in the hydrophilic module. The optimal speed-up method can reduce the total CPU cost by up to a factor of 31.4 from benchmark under the rural conditions with 2 ppb isoprene and by factors of 10 71 under various test conditions with 2 10 ppb isoprene and >40% relative humidity while maintaining ±15% deviation. These speed-up methods are applicable to other SOA modules that are based on partitioning theories.

  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. 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...

  11. 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...

  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. "Zafar," So Good: Middle-Class Students, School Habitus and Secondary Schooling in the City of Buenos Aires (Argentina)

    Science.gov (United States)

    Meo, Analia Ines

    2011-01-01

    This article examines how students from the "loser" sections of the middle class dealt with the game of secondary schooling in a "good" state school in the city of Buenos Aires (Argentina). It engages with Bourdieu's theory of social practice and, in particular, with its concepts of game, habitus and cultural capital. It argues…

  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. Gravitational Waves from Preheating in M-flation

    CERN Document Server

    Ashoorioon, Amjad; Mann, Robert B; Oltean, Marius; Sheikh-Jabbari, M M

    2014-01-01

    Matrix inflation, or M-flation, is a string theory motivated inflationary model with three scalar field matrices and gauge fields in the adjoint representation of the $\\mathbf{U}(N)$ gauge group. One of these $3N^2$ scalars appears as the effective inflaton while the rest of the fields (scalar and gauge fields) can play the role of isocurvature fields during inflation and preheat fields afterwards. There is a region in parameter space and initial field values, "the hilltop region," where predictions of the model are quite compatible with the recent \\textit{Planck} data. We show that in this hilltop region, if the inflaton ends up in the supersymmetric vacuum, the model can have an embedded preheating mechanism. % only if inflation happens around the supersymmetric vacuum. % Couplings of the preheat modes are related to the inflaton self-couplings and therefore are known from the CMB data. Through lattice simulations performed using a symplectic integrator, we numerically compute the power spectra of gravitati...

  17. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    Directory of Open Access Journals (Sweden)

    B. B. Palm

    2015-11-01

    Full Text Available Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA formation and aging. High OH concentrations and short residence times allowed for semi-continuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq. atmospheric aging. A simple model is derived and used to account for the relative time scales of condensation of low volatility organic compounds (LVOCs onto particles, condensational loss to the walls, and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 4 μg m-3 when LVOC fate corrected compared to daytime (average 1 μg m-3 when LVOC fate corrected, with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene + p-cymene concentrations, including a substantial increase just after sunrise at 07:00 LT. Higher photochemical aging (> 10 eq. days led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254, similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH

  18. Distribution of air and serum PCDD/F levels of electric arc furnaces and secondary aluminum and copper smelters.

    Science.gov (United States)

    Lee, Ching-Chang; Shih, Tung-Seng; Chen, Hsiu-Ling

    2009-12-30

    Metallurgical processes, such as smelting, can generate organic impurities such as organic chloride chemicals, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The objective of this study was to elucidate the serum PCDD/F levels of 134 workers and ambient air levels around electric arc furnaces (EAF), secondary copper smelters and secondary aluminum smelters (ALSs) in Taiwan. The highest serum PCDD/F levels were found in the ALSs workers (21.9 pg WHO-TEQ/g lipid), with lower levels in copper smelter workers (21.5 pg WHO-TEQ/g lipid), and the lowest in the EAF plant workers (18.8 pg WHO-TEQ/g lipid). This was still higher than the levels for residents living within 5 km of municipal waste incinerators (14.0 pg WHO-TEQ/g lipid). For ambient samples, the highest ambient air PCDD/F level was in the copper smelters (12.4 pg WHO-TEQ/Nm(3)), with lower levels in ALSs (7.2 pg WHO-TEQ/Nm(3)), and the lowest in the EAF industry (1.8 pg WHO-TEQ/Nm(3)). The congener profiles were consistent in serum and in air samples collected in the copper smelters, but not for ALSs and EAF. In secondary copper smelters, the air PCDD/Fs levels might be directly linked to the PCDD/Fs accumulated in the workers due to the exceedingly stable congener pattern of the PCDD/F emission.

  19. Mineralogy of air-pollution-control residues from a secondary lead smelter: environmental implications.

    Science.gov (United States)

    Ettler, Vojtech; Johan, Zdenek; Baronnet, Alain; Jankovsky, Filip; Gilles, Christian; Mihaljevic, Martin; Sebek, Ondrej; Strnad, Ladislav; Bezdicka, Petr

    2005-12-01

    The mineralogy and solubility of air-pollution-control (APC) residues from a secondary lead (Pb) smelter have been studied on samples from the Príbram smelter, Czech Republic, recycling car batteries, with the emphasis on their potential environmental effect. The presence of dominant anglesite (PbSO4) and laurionite (Pb(OH)Cl) was observed in a sintered residue from after-burning chambers (800-1000 degrees C). In contrast, low-temperature Pb-bearing phases, such as KCl x 2PbCl2 and caracolite (Na3Pb2(SO4)3Cl), were detected in the major APC residue from bag-type fabric filters. Metallic elements, zinc (Zn), cadmium (Cd), and tin (Sn) were found homogeneously distributed within this residue. The formation of anglesite, cotunnite (PbCl2), (Zn,Cd)2SnO4, and (Sb,As)2O3 was observed during the sintering of this APC residue at 500 degrees C in a rotary furnace. The 168 h leaching test on filter residue, representing the fraction that may escape the flue gas treatment system, indicated rapid release of Pb and other contaminants. Caracolite and KCl x 2PbCl2 are significantly dissolved, and anglesite and cotunnite form the alteration products, as was confirmed by mineralogical analysis and PHREEQC-2 modeling. The observed Pb-bearing chlorides have significantly higher solubility than anglesite and, following emission from the smelter stack, can readily dissolve, transferring Pb into the environmental milieu (soils, water, inhabited areas).

  20. Low SO2 Emission Preheaters for Cement Production

    DEFF Research Database (Denmark)

    Rasmussen, Martin Hagsted

    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...... in a preheater tower. The idea is to account for the complex flow pattern in a cyclone stage by dividing it into zones, each zone having special features. In this manner the model can account for gas/solid heat exchange, gas/solid separation, different gas and solid residence times, etc. The model was evaluated...

  1. Parametric resonance of entropy perturbations in massless preheating

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert H.; Cai, Yi-Fu; Ferreira, Elisa G. M.

    2015-07-01

    In this paper, we revisit the question of possible preheating of entropy modes in a two-field model with a massless inflaton coupled to a matter scalar field. Using a perturbative approximation to the covariant method we demonstrate that there is indeed a parametric instability of the entropy mode which then at second-order leads to exponential growth of the curvature fluctuation on super-Hubble scale. Back-reaction effects shut off the induced curvature fluctuations, but possibly not early enough to prevent phenomenological problems. This confirms previous results obtained using different methods and resolves a controversy in the literature.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. Effect of preheating on the film thickness of contemporary composite restorative materials

    Directory of Open Access Journals (Sweden)

    Dimitrios Dionysopoulos

    2014-12-01

    Conclusion: The film thickness of the composites tested is material dependent. The thickness of the preheated conventional composites is significantly lower than those at room temperature. The conventional composites provide film thickness values greater than those of the flowable composites regardless of preheating temperature.

  10. Diagnostic Air Quality Model Evaluation of Source-Specific Primary and Secondary Fine Particulate Carbon

    Science.gov (United States)

    Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004–February 2005) provided an unprecedented opportunity to diagnostically evaluate...

  11. Molten salt parabolic trough system with synthetic oil preheating

    Science.gov (United States)

    Yuasa, Minoru; Hino, Koichi

    2017-06-01

    Molten salt parabolic trough system (MSPT), which can heat the heat transfer fluid (HTF) to 550 °C has a better performance than a synthetic oil parabolic trough system (SOPT), which can heat the HTF to 400 °C or less. The utilization of HTF at higher temperature in the parabolic trough system is able to realize the design of a smaller size of storage tank and higher heat to electricity conversion efficiency. However, with MSPT there is a great amount of heat loss at night so it is necessary to circulate the HTF at a high temperature of about 290 °C in order to prevent solidification. A new MSPT concept with SOPT preheating (MSSOPT) has been developed to reduce the heat loss at night. In this paper, the MSSOPT system, its performance by steady state analysis and annual performance analysis are introduced.

  12. 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.

  13. 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.

  14. 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.

  15. Influence of the mass flow rate of secondary air on the gas/particle flow characteristics in the near-burner region of a double swirl flow burner

    Energy Technology Data Exchange (ETDEWEB)

    Jing, J.P.; Li, Z.Q.; Wang, L.; Chen, Z.C.; Chen, L.Z.; Zhang, F.C. [Harbin Institute of Technology, Harbin (China)

    2011-06-15

    The influence of the mass flow rate of secondary air on the gas/particle flow characteristics of a double swirl flow burner, in the near-burner region, was measured by a three-component particle-dynamics anemometer, in conjunction with a gas/particle two-phase test facility. Velocities, particle volume flux profiles, and normalized particle number concentrations were obtained. The relationship between the gas/particle flows and the combustion characteristics of the burners was discussed. For different mass flow rates of secondary air, annular recirculation zones formed only in the region of r/d=0.3-0.6 at x/d=0.1-0.3. With an increasing mass flow rate of secondary air, the peaks of the root mean square (RMS) axial fluctuating velocities, radial mean velocities, RMS radial fluctuating velocities, and tangential velocities all increased, while the recirculation increased slightly. There was a low particle volume flux in the central zone of the burner. At x/d=0.1-0.7, the profiles of particle volume flux had two peaks in the secondary air flow zone near the wall. With an increasing mass flow rate of secondary air, the peak of particle volume flux in the secondary air flow zone decreased, but the peak of particle volume flux near the wall increased. In section x/d=0.1-0.5, the particle diameter in the central zone of the burner was always less than the particle diameter at other locations.

  16. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Science.gov (United States)

    2010-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... AIR QUALITY STANDARDS Pt. 50, App. I Appendix I to Part 50—Interpretation of the 8-Hour Primary and... valid day if valid 8-hour averages are available for at least 75% of possible hours in the day (i.e.,...

  17. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... AIR QUALITY STANDARDS Pt. 50, App. H Appendix H to Part 50—Interpretation of the 1-Hour Primary and...

  18. Secondary Organic Aerosol Formation from Ambient Air in an Oxidation Flow Reactor at GoAmazon2014/5

    Science.gov (United States)

    Palm, Brett B.; de Sa, Suzane S.; Campuzano-Jost, Pedro; Day, Douglas A.; Hu, Weiwei; Seco, Roger; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Brito, Joel; Wurm, Florian; Artaxo, Paulo; Yee, Lindsay; Isaacman-VanWertz, Gabrial; Goldstein, Allen; Newburn, Matt K.; Lizabeth Alexander, M.; Martin, Scot T.; Brune, William H.; Jimenez, Jose L.

    2016-04-01

    During GoAmazon2014/5, ambient air was exposed to controlled concentrations of OH or O3 in situ using an oxidation flow reactor (OFR). Oxidation ranged from hours-several weeks of aging. Oxidized air was sampled by several instruments (e.g., HR-AMS, ACSM, PTR-TOF-MS, SMPS, CCN) at both the T3 site (IOP1: Feb 1-Mar 31, 2014, and IOP2: Aug 15-Oct 15, 2014) and T2 site (between IOPs and into 2nd IOP). The oxidation of ambient air in the OFR led to substantial and variable secondary organic aerosol (SOA) formation from any SOA-precursor gases, known and unknown, that entered the OFR. In general, more SOA was produced during the nighttime than daytime, suggesting that SOA-precursor gases were found in relatively higher concentrations at night. Similarly, more SOA was formed in the dry season (IOP2) than wet season (IOP1). The maximum amount of SOA produced during nighttime from OH oxidation ranged from less than 1 μg/m3 on some nights to greater than 10 μg/m3 on other nights. O3 oxidation of ambient air also led to SOA formation, although several times less than from OH oxidation. The amount of SOA formation sometimes, but not always, correlated with measured gas-phase biogenic and/or anthropogenic SOA precursors (e.g., SV-TAG sesquiterpenes, PTR-TOFMS aromatics, isoprene, and monoterpenes). The SOA mass formed in the OFR from OH oxidation was up to an order of magnitude larger than could be explained from aerosol yields of measured primary VOCs. This along with measurements from previous campaigns suggests that most SOA was formed from intermediate S/IVOC sources (e.g., VOC oxidation products, evaporated POA, or direct emissions). To verify the SOA yields of VOCs under OFR experimental conditions, atmospherically-relevant concentrations of several VOCs were added individually into ambient air in the OFR and oxidized by OH or O3. SOA yields in the OFR were similar to published chamber yields. Preliminary PMF factor analysis showed production of secondary factors in

  19. Simulation of unsteady state performance of a secondary air system by the 1D-3D-Structure coupled method

    Science.gov (United States)

    Wu, Hong; Li, Peng; Li, Yulong

    2016-02-01

    This paper describes the calculation method for unsteady state conditions in the secondary air systems in gas turbines. The 1D-3D-Structure coupled method was applied. A 1D code was used to model the standard components that have typical geometric characteristics. Their flow and heat transfer were described by empirical correlations based on experimental data or CFD calculations. A 3D code was used to model the non-standard components that cannot be described by typical geometric languages, while a finite element analysis was carried out to compute the structural deformation and heat conduction at certain important positions. These codes were coupled through their interfaces. Thus, the changes in heat transfer and structure and their interactions caused by exterior disturbances can be reflected. The results of the coupling method in an unsteady state showed an apparent deviation from the existing data, while the results in the steady state were highly consistent with the existing data. The difference in the results in the unsteady state was caused primarily by structural deformation that cannot be predicted by the 1D method. Thus, in order to obtain the unsteady state performance of a secondary air system more accurately and efficiently, the 1D-3D-Structure coupled method should be used.

  20. Environmental Learning Workshop: Lichen as Biological Indicator of Air Quality and Impact on Secondary Students' Performance

    Science.gov (United States)

    Samsudin, Mohd Wahid; Daik, Rusli; Abas, Azlan; Meerah, T. Subahan Mohd; Halim, Lilia

    2013-01-01

    In this study, the learning of science outside the classroom is believe to be an added value to science learning as well as it offers students to interact with the environment. This study presents data obtained from two days' workshop on Lichen as Biological Indicator for Air Quality. The aim of the workshop is for the students to gain an…

  1. 77 FR 555 - National Emissions Standards for Hazardous Air Pollutants From Secondary Lead Smelting

    Science.gov (United States)

    2012-01-05

    ... Regulatory Text G. Emission Testing Methods and Frequency H. Startup, Shutdown, and Malfunction VI. Summary... the EPA's CAA section 112 regulations governing the emissions of HAP during periods of startup... while improving the quality of emission inventories and, as a result, air quality regulations....

  2. 76 FR 29031 - National Emissions Standards for Hazardous Air Pollutants: Secondary Lead Smelting

    Science.gov (United States)

    2011-05-19

    ... those sources. ``Major sources'' are those that emit or have the potential to emit 10 tons per year (tpy... composed primarily of metal HAP. Fugitive dust emissions result from the entrainment of HAP in ambient air... the maximum target organ-specific hazard index (TOSHI) for chronic exposures to HAP with the...

  3. 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.

  4. 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.

  5. 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...

  6. Heat Transfer and Observation of Droplet-Surface Interactions During Air-Mist Cooling at CSP Secondary System Temperatures

    Science.gov (United States)

    Huerta L., Mario E.; Mejía G., M. Esther; Castillejos E., A. Humberto

    2016-04-01

    Air-mists are key elements in the secondary cooling of modern thin steel slab continuous casters. The selection of water, W, and air, A, flow rates, and pressures in pneumatic nozzles open up a wide spectrum of cooling possibilities by their influence on droplet diameter, d, droplet velocity, v, and water impact flux, w. Nonetheless, due to the harsh environment resulting from the high temperatures and dense mists involved, there is very little information about the correlation between heat flux extracted, - q, and mist characteristics, and none about the dynamics of drop-wall interactions. For obtaining both kinds of information, this work combines a steady-state heat flux measuring method with a visualization technique based on a high-speed camera and a laser illumination system. For wall temperatures, T w, between ~723 K and ~1453 K (~450 °C and ~1180 °C), which correspond to film boiling regime, it was confirmed that - q increases with increase in v, w, and T w and with decrease in d. It should be noticed, however, that the increase in w generally decreases the spray cooling effectiveness because striking drops do not evaporate efficiently due to the interference by liquid remains from previous drops. Visualization of the events happening close to the surface also reveals that the contact time of the liquid with the surface is very brief and that rebounding, splashing, sliding, and levitation of drops lead to ineffective contact with the surface. At the center of the mist footprint, where drops impinge nearly normal to the surface those with enough momentum establish intimate contact with it before forming a vapor layer that pushes away the remaining liquid. Also, some drops are observed sliding upon the surface or levitating close to it; these are drops with low momentum which are influenced by the deflecting air stream. At footprint positions where oblique impingement occurs, frequently drops are spotted sliding or levitating and liquid films flowing in

  7. 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.

  8. 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.

  9. 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...

  10. 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.

  11. Corneal abrasion and alkali burn secondary to automobile air bag inflation

    Science.gov (United States)

    Scarlett, Angela; Gee, Paul

    2007-01-01

    A 59‐year‐old woman self presented to the emergency department with a painful right eye following a motor vehicle accident. She had reduced visual acuity and the eye had an alkaline pH with complete corneal uptake of fluorescein. Diagnosis of corneal abrasion and alkali burn to her right eye secondary to inflation of a driver's automobile airbag was made. The eye was irrigated with normal saline. Such injuries, although rare, can easily be identified within the emergency department by the history of exposure, evidence of facial injuries or burns, and an alkaline pH in the inferior cul‐de‐sac of the eye. Early detection and management with ophthalmology review is therefore imperative to prevent irreversible visual impairment. PMID:17901284

  12. 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)

  13. Angular deviation of secondary charge particles in 1014-1016 eV extensive air showers: Constrains on application of hodoscopes

    Directory of Open Access Journals (Sweden)

    D Purmohammad

    2012-12-01

    Full Text Available   Deviation angles of secondary electrons and muons in simulated extensive air showers were studied. The angles have wide distribution, whose width depends on energy cuts imposed on shower particles. In this work, variation of deviation angles with the energy of secondary particles, shower energy, primary direction, and core distance was investigated. The results put limitations on application of hodoscopic devices in cosmic ray and gamma ray observations.

  14. Waste Heat Recovery from the Advanced Test Reactor Secondary Coolant Loop

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen

    2012-11-01

    This study investigated the feasibility of using a waste heat recovery system (WHRS) to recover heat from the Advanced Test Reactor (ATR) secondary coolant system (SCS). This heat would be used to preheat air for space heating of the reactor building, thus reducing energy consumption, carbon footprint, and energy costs. Currently, the waste heat from the reactor is rejected to the atmosphere via a four-cell, induced-draft cooling tower. Potential energy and cost savings are 929 kW and $285K/yr. The WHRS would extract a tertiary coolant stream from the SCS loop and pump it to a new plate and frame heat exchanger, from which the heat would be transferred to a glycol loop for preheating outdoor air supplied to the heating and ventilation system. The use of glycol was proposed to avoid the freezing issues that plagued and ultimately caused the failure of a WHRS installed at the ATR in the 1980s. This study assessed the potential installation of a new WHRS for technical, logistical, and economic feasibility.

  15. Size and Velocity Characteristics of Droplets Generated by Thin Steel Slab Continuous Casting Secondary Cooling Air-Mist Nozzles

    Science.gov (United States)

    Minchaca M, J. I.; Castillejos E, A. H.; Acosta G, F. A.

    2011-06-01

    Direct spray impingement of high temperature surfaces, 1473 K to 973 K (1200 °C to 700 °C), plays a critical role in the secondary cooling of continuously cast thin steel slabs. It is known that the spray parameters affecting the local heat flux are the water impact flux w as well as the droplet velocity and size. However, few works have been done to characterize the last two parameters in the case of dense mists ( i.e., mists with w in the range of 2 to 90 L/m2s). This makes it difficult to rationalize how the nozzle type and its operating conditions must be selected to control the cooling process. In the present study, particle/droplet image analysis was used to determine the droplet size and velocity distributions simultaneously at various locations along the major axis of the mist cross section at a distance where the steel strand would stand. The measurements were carried out at room temperature for two standard commercial air-assisted nozzles of fan-discharge type operating over a broad range of conditions of practical interest. To achieve statistically meaningful samples, at least 6000 drops were analyzed at each location. Measuring the droplet size revealed that the number and volume frequency distributions were fitted satisfactorily by the respective log-normal and Nukiyama-Tanasawa distributions. The correlation of the parameters of the distribution functions with the water- and air-nozzle pressures allowed for reasonable estimation of the mean values of the size of the droplets generated. The ensemble of measurements across the mist axis showed that the relationship between the droplet velocity and the diameter exhibited a weak positive correlation. Additionally, increasing the water flow rate at constant air pressure caused a decrease in the proportion of the water volume made of finer droplets, whereas the volume proportion of faster droplets augmented until the water flow reached a certain value, after which it decreased. Diminishing the air

  16. Enhanced formation of secondary air pollutants and aggravation of urban smog due to crop residue burning emissions in North India

    Science.gov (United States)

    Sarkar, Chinmoy; Kumar, Vinod; Sinha, Vinayak

    2013-04-01

    implications for the oxidizing capacity of the atmosphere increased from an average value of 14 /s (N.F.E.) to 40 /s (F.E.) just due to CO, NOx and the measured aromatics. The observed increase in ozone was 10ppbV higher after sunrise on the day after the fire plume was sampled and driven by the sudden NOx availability at a site that normally falls in a NOx limited ozone production regime. The strong pollutant enhancements in carcinogenic aromatic hydrocarbons that are also highly reactive and fuel ozone and secondary organic aerosol formation when accompanied by the high NOx and CO levels resulting from crop residue burning in N. India, clearly highlight the need to address the practice of crop residue burning which strongly alters the composition and chemistry of the atmosphere with adverse effects on both air quality and health. This study is the first from within India to combine fast in-situ PTR-MS VOC emission tracer measurements with online measurements of primary pollutants and MODIS satellite data. Further targeted studies employing a comprehensive measurement suite of both aerosol and gas species are needed to assess the full impact of crop residue burning on atmospheric chemistry and regional air quality. Acknowledgement: We thank the IISER Mohali Atmospheric Chemistry Facility for data and the Ministry of Human Resource Development (MHRD),India and IISER Mohali for funding the facility. Vinod Kumar acknowledges the DST INSPIRE Fellowship programme. Chinmoy Sarkar thanks the Max Planck-DST India Partner Group on Tropospheric OH reactivity and VOCs for funding support.

  17. Stability of carbon electrodes for aqueous lithium-air secondary batteries

    Science.gov (United States)

    Ohkuma, Hirokazu; Uechi, Ichiro; Matsui, Masaki; Takeda, Yasuo; Yamamoto, Osamu; Imanishi, Nobuyuki

    2014-01-01

    The air electrode performance of various carbon materials, such as Ketjen black (KB), acetylene black (AB and AB-S), Vulcan XC-72R (VX), and vapor grown carbon fiber (VGCF) with and without La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) catalyst were examined in an aqueous solution of saturated LiOH with 10 M LiCl in the current density range 0.2-2.0 mA cm-2. The best performance for oxygen reduction and evolution reactions was observed for the KB electrode, which has the highest surface area among the carbon materials examined. A steady over-potential of 0.2 V was obtained for the oxygen reduction reaction using the KB electrode without the catalyst, while the over-potential was 0.15 V for KB with the LSCF catalyst at 2.0 mA cm-2. The over-potentials for the oxygen evolution reaction were slightly higher than those for the oxygen reduction reaction, and gradually increased with the polarization period. Analysis of the gas in the cell after polarization above 0.4 V revealed the evolution of a small amount of CO during the oxygen evolution reaction by the decomposition of carbon in the electrode. The amount of CO evolved was significantly decreased by the addition of LSCF to the carbon electrode.

  18. 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.

  19. 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).

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Monitoring and Modelling the Trends of Primary and Secondary Air Pollution Precursors: The Case of the State of Kuwait

    Directory of Open Access Journals (Sweden)

    S. M. Al-Salem

    2010-01-01

    Full Text Available Since the beginning of the industrial revolution, processes of different scales have contributed greatly to the pollution and waste load on the environment. More specifically, airborne pollutants associated with chemical processes have contributed greatly on the ecosystem and populations health. In this communication, we review recent activities and trends of primary and secondary air pollutants in the state of Kuwait, a country associated with petroleum, petrochemical, and other industrial pollution. Trends of pollutants and impact on human health have been studied and categorized based on recent literature. More attention was paid to areas known to researchers as either precursor sensitive (i.e., nitrogen oxides (NOx, volatile organic compounds (VOCs or adjacent to upstream- or downstream-related activities. Environmental monitoring and modelling techniques relevant to this study are also reviewed. Two case studies that link recent data with models associated with industrial sectors are also demonstrated, focusing mainly on chemical mass balance (CMB and Gaussian line source modelling. It is concluded that a number of the monitoring stations and regulations placed by the Kuwait Environment Public Authority (KUEPA need up-to-date revisions and better network placement, in agreement with previous findings.

  5. 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.

  6. 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.

  7. 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. 

  8. 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

  9. 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...

  10. Study on the Effect of the Side Secondary Air Velocity on the Aerodynamic Field in a Tangentially Fired Furnace with HBC—SSA Burner

    Institute of Scientific and Technical Information of China (English)

    ZhuTong; SunShaozeng; 等

    1999-01-01

    The present paper has compared a group of furnace aerodynamic fields at different velocities of side secondary air(SSA) in a test model of 420t/h utility boiler,applying Horizontal Bias Conbustion Pulverized Coal Burner with Side Secondary AIr(HBC-SSA Burner).Experimental results show that,when the ram pressure ratio of side secondary air(SSA) to primary air(PA) ρ2sv232/ρ1v12)is between 1.0-2.4,the furnace aerodynamic field only varies slightly.The relative rotational diameters(φ/L)in the burner domain are moderate and the furnace is in good fullness.Whenρ2s v232/ρ1v12 is beyond4,φ/L is so large that the stream sweeps water-cooled wall and rotateds strongly in the furnace.Therefore,slagging and high temperature corrosion of tube metal will be formed on the water-cooled wall in actual operation.This investigation provides the basis for the application of this new type burner.In addition,numerical simulations are conducted,and some defects in the numerical simulation are also pointed out and analyzed in this paper.

  11. Fresh air supply in airtight, well insulated houses; Friskluftforsyning i taette, velisolerede huse

    Energy Technology Data Exchange (ETDEWEB)

    Wittchen, K.

    1988-12-01

    Modern Danish houses are often built with a great respect for insulation and air tightness. Because of this it can be necessary to install mechanical ventilation systems in order to obtain a good indoor air quality. To meet the demand for low energy consumption, air-to-air heat exchangers are often added to the ventilation systems. Heat exchangers typically operate with a thermal efficiency of 0.6-0.7. However it is possible to achieve further energy savings by preheating the cold ventilation air before it reaches the heat exchanger. This preheating could be achieved by leading the cold air through surroundings with a temperature higher than the external air temperature. Surroundings of this kind can be found in attics, crawl spaces, underground ducts etc. Analysis have been made of the preheating of the ventilation air in 3 of 6 monitored low energy houses at Hjortekaer, about 20 km north of Copenhagen. The houses each had different types of ventilation systems with heat exchangers, namely preheating in an attic, preheating in a crawl space and a traditional simple ventilation system in a low energy house. Furthermore, a theoretical analysis of the preheating in an underground duct system has been made. Investigations showed that compatibility is best between heating demand and possible energy gain when the preheating comes from a ground-connected system (crawl spaces or an underground duct system). Ventilation systems of this type will, beside the preheating gains, offer the opportunity of cooling the house in periods with high ambient temperatures. (AB) 57 p.

  12. 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.

  13. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite.

    Science.gov (United States)

    Theobaldo, Jéssica Dias; Aguiar, Flávio Henrique Baggio; Pini, Núbia Inocencya Pavesi; Lima, Débora Alves Nunes Leite; Liporoni, Priscila Christiane Suzy; Catelan, Anderson

    2017-01-01

    The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC), microhardness (KHN), plasticization (P), and depth of polymerization (DP) of a bulk fill composite. Forty disc-shaped samples (n = 5) of a bulk fill composite were prepared (5 × 4 mm thick) and randomly divided into 4 groups according to light-curing unit (quartz-tungsten-halogen [QTH] or light-emitting diode [LED]) and preheating temperature (23 or 54 °C). A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey's test (α = 0.05). Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill. Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. 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 ...

  1. 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...... this kind of collectors. The modified simulation program has been used for the determination of the surplus in performance which solar heating systems with this type of solar collectors for combined preheating of ventilation air and domestic hot water will have. The simulation program and the efficiency...

  2. Synthesis and electrochemical performance of La0.7Sr0.3Co1-xFexO3 catalysts for zinc air secondary batteries

    Science.gov (United States)

    Ahn, Seyoung; Kim, Ketack; Kim, Hyunsoo; Nam, Sangyong; Eom, Seungwook

    2010-05-01

    We prepared La0.7Sr0.3Co1-xFexO3 (x=0.1-0.4) catalysts for a zinc air battery by using the citrate method under controlled pH. The prepared precursor powder was heat treated at the calcination temperature of 700 °C and examined for the optimum structure of the cathode. The structure and performance of the catalysts were examined by x-ray diffraction and a scanning electron microscope. The air electrode was prepared by blending the catalyst, Vulcan XC-72R (carbon black), and (polytetrafluoroethylene PTFE) suspension. The oxygen reduction reaction and the oxygen evolution reaction were examined by linear sweep voltammetry. The results showed that La0.7Sr0.3Co0.7Fe0.3O3 (LSCF0.7) is an excellent catalyst for the zinc air secondary battery.

  3. 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.

  4. 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.

  5. Experimental analysis of secondary flow in turbines (with cooling air ejection). Final report; Experimentelle Analyse der Sekundaerstroemungen in Turbinen (mit Kuehlluftausblasung). Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Langowsky, C. [ed.; Weyer, H.B.

    1997-09-01

    Film cooling is an effective method of blade surface cooling. To satisfy not only the thermal but also the aerodynamic demand of minimum loss production the detailed knowledge of the interaction between the cooling air and the main flow is necessary. In this work the effect of cooling air ejection on the aerodynamics of the cascade flow and its loss production is studied experimentally with varied Blowing ratios and locations. Furthermore the mixing process of the cooling air jets among the influence of the secondary flow is investigated. To be able to analyse the different superimposed effects (radial pressure gradient, secondary flow) various measurement techniques are used. By means of additional numerical flow simulations origins of the experimental indicated effects could be figured out. (orig.) [Deutsch] Filmkuehlung ist eine wirkungsvolle Methode zur Kuehlung der aeusseren Schaufeloberflaeche. Um neben den thermischen auch den aerodynamischen Anspruechen nach einer minimalen Verlustproduktion zu genuegen, ist die genaue Kenntnis der wechselseitigen Beeinflussung von ausgeblasener Kuehlluft und Hauptstroemung notwendig. Gegensteand der vorliegenden Arbeit ist die experimentelle Untersuchung der Auswirkungen der Kuehlluftausblasung auf die Aerodynamik der Hauptstroemung eines filmgekuehlten Turbinenstators und auf dessen Verlustproduktion bei Variation des Ausblaseortes und der Ausblaserate. Desweiteren wurde die Mischungscharakteristik der Kuehlluftstrahlen unter besonderer Beruecksichtigung des Einflusses der Sekundaerstroemung studiert. Um die unterschiedlichen Wirkungen sich ueberlagernder Einfluesse (radialer Druckgradient, Sekundaerstroemung) analysieren zu koennen, wurden verschiedene Messtechniken eingesetzt. Begleitende numerische Simulationen der Stroemungsvorgaenge ermoeglichten Aussagen zu den Ursachen der experimentell aufgedeckten Effekte. (orig.)

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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...

  12. 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.

  13. 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.

  14. 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...

  15. Growth under elevated air temperature alters secondary metabolites in Robinia pseudoacacia L. seedlings in Cd- and Pb-contaminated soils.

    Science.gov (United States)

    Zhao, Y H; Jia, X; Wang, W K; Liu, T; Huang, S P; Yang, M Y

    2016-09-15

    Plant secondary metabolites play a pivotal role in growth regulation, antioxidant activity, pigment development, and other processes. As the global climate changes, increasing atmospheric temperatures and contamination of soil by heavy metals co-occur in natural ecosystems, which alters the pH of rhizosphere soil and influences the bioavailability and mobility of metals. Elevated temperatures in combination with heavy metals are expected to affect plant secondary metabolites, but this issue has not been extensively examined. Here, we investigated secondary metabolites in Robiniapseudoacacia seedlings exposed to elevated temperatures using a passive warming device in combination with Cd- and Pb-contaminated soils. Heavy metals significantly stimulated the accumulation of saponins, phenolic compounds, and flavonoids in leaves and stems; alkaloid compounds increased in leaves and decreased in stems, and condensed tannins fluctuated. Elevated temperatures, alone and in combination with Cd and Pb, caused increases in secondary metabolites in the plant tissues. Phenolic compounds showed the greatest changes among the secondary metabolites and significant interactive effects of temperature and metals were observed. These results suggest that slightly elevated temperature could enhance protective and defense mechanisms of Robinia pseudoacacia seedlings exposed to heavy metals by stimulating the production of secondary metabolites.

  16. 2005 Mississippi Curriculum Framework: Secondary Heating and Air Conditioning. (Program CIP: 47.0201 - Heating, Air Conditioning, Ventilation, and Refrigeration Maintenance Technology/Technician)

    Science.gov (United States)

    Green, Jacob; LeBatard, Ernest; Wiggington, Donnie; Williams, Bennett

    2005-01-01

    Secondary vocational-technical education programs in Mississippi are faced with many challenges resulting from sweeping educational reforms at the national and state levels. Schools and teachers are increasingly being held accountable for providing true learning activities to every student in the classroom. This accountability is measured through…

  17. Effect of preheating on the film thickness of contemporary composite restorative materials

    OpenAIRE

    Dimitrios Dionysopoulos; Kosmas Tolidis; Paris Gerasimou; Eugenia Koliniotou-Koumpia

    2014-01-01

    Background/purpose: Recently, the placement of composite materials at an elevated temperature has been proposed in order to increase their flow for better adaptation in cavity walls. The aim of this in vitro study was to evaluate the effect of preheating on the film thickness of a variety of commercially available conventional composites and to compare them with those obtained from a variety of flowable composites at room temperature. Materials and methods: The composites were three nanohy...

  18. 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.

  19. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite

    Directory of Open Access Journals (Sweden)

    Theobaldo JD

    2017-05-01

    Full Text Available Jéssica Dias Theobaldo,1 Flávio Henrique Baggio Aguiar,1 Núbia Inocencya Pavesi Pini,2 Débora Alves Nunes Leite Lima,1 Priscila Christiane Suzy Liporoni,3 Anderson Catelan3 1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, 2Ingá University Center, Maringá, 3Departament of Dentistry, University of Taubaté, Taubaté, Brazil Objective: The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC, microhardness (KHN, plasticization (P, and depth of polymerization (DP of a bulk fill composite.Methods: Forty disc-shaped samples (n = 5 of a bulk fill composite were prepared (5 × 4 mm thick and randomly divided into 4 groups according to light-curing unit (quartz–tungsten–halogen [QTH] or light-emitting diode [LED] and preheating temperature (23 or 54 °C. A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey’s test (α = 0.05.Results: Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill.Conclusion: Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated. Keywords: composite resins, physicochemical phenomena, polymerization, hardness, heating

  20. Boron Particle Ignition in Secondary Chamber of Ducted Rocket

    Directory of Open Access Journals (Sweden)

    J. X. Hu

    2012-01-01

    Full Text Available In the secondary chamber of ducted rocket, there exists a relative speed between boron particles and air stream. Hence, the ignition laws under static conditions cannot be simply applied to represent the actual ignition process of boron particles, and it is required to study the effect of forced convective on the ignition of boron particles. Preheating of boron particles in gas generator makes it possible to utilize the velocity difference between gas and particles in secondary chamber for removal of the liquid oxide layer with the aid of Stoke's forces. An ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism. The shearing action exerted by the high-speed flow causes a boundary layer to be formed in the surface of the liquid oxide layer, and the stripping away of this layer accounts for the accelerated ignition of boron particles. Compared with the King model, as the ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism, the oxide layer thickness thins at all times during the particle ignition and lower the ignition time.

  1. 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.

  2. 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.

  3. Marginal and internal analysis of preheated dental fissure-sealing materials using optical coherence tomography.

    Science.gov (United States)

    Borges, Boniek Castillo Dutra; de Assunção, Isauremi Vieira; de Aquino, Célia Avani; de Melo Monteiro, Gabriela Queiroz; Gomes, Anderson Stevens Leonidas

    2016-02-01

    This study aimed to evaluate the influence of pre-photoactivation temperature on the marginal and internal integrity (occurrence of voids) of fissure-sealing materials on occlusal fissures using optical coherence tomography (OCT). Occlusal fissures of 40 human third molars were sealed using a resin-based fissure sealant (Fluroshield) and a flowable composite (Permaflo) photoactivated at 68 °C (preheated) or at room temperature (25 °C) (n=10). After sealing, the teeth were subjected to thermocycling (500 cycles, 5-55 °C) and 14 days of pH cycling (demineralisation for 6 hours/day and remineralisation for 18 hours/day). The occlusal surfaces were scanned in a buccolingual direction, and 20 tomographic images parallel to the long axis of each tooth were obtained. Images presenting marginal gaps and internal voids were counted and statistically analysed using analysis of variance and Tukey's test (Pinternal voids than the resin-based sealant. Preheated materials had a lower percentage of gaps and internal voids than the materials at room temperature. Therefore, preheated flowable composite provided the best marginal sealing of fissures, and internal homogeneity of the material. © 2015 FDI World Dental Federation.

  4. Influence of ageing, grinding and preheating on the thermal behaviour of alpha-lactose monohydrate.

    Science.gov (United States)

    Garnier, S; Petit, S; Mallet, F; Petit, M-N; Lemarchand, D; Coste, S; Lefebvre, J; Coquerel, G

    2008-09-01

    It is shown that the onset temperature and the magnitude of thermal events observed during DSC analyses of alpha-lactose monohydrate can be strongly affected by various treatments such as ageing, manual grinding and preheating (cycle of preliminary dehydration and rehydration). In the case of grinding and preheating, the change of dehydration pathways was further investigated by using a suitable combination of characterization techniques, including X-ray powder diffraction (XRPD) performed with a synchrotron source (allowing an accurate Rietveld analysis), scanning electron microscopy (SEM), laser particle size measurements, FTIR spectroscopy and (1)H NMR for the determination of beta-lactose contents in samples. It appeared that the dehydration mechanism is affected not only by a smaller particle size distribution, but also by residual anisotropic lattice distortions and by the formation of surface defects or high energy surfaces. The fusion-recrystallization process occurring between anhydrous forms of alpha-lactose at ca. 170 degrees C is not significantly affected by grinding, whereas a preheating treatment induces an unexpected large increase of the enthalpy associated with this transition. Our observations and interpretations confirm the important role of water molecules in the crystal cohesion of the title compound and illustrate the necessity to consider the history of each sample for a satisfactory understanding of the physical properties and the behaviour of this important pharmaceutical excipient.

  5. 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.

  6. 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.

  7. 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.

  8. Qualification and Testing of a Large Hot Slumped Secondary Mirror for Schwarzschild-Couder Imaging Air Cherenkov Telescopes

    Science.gov (United States)

    Rodeghiero, G.; Giro, E.; Canestrari, R.; Pernechele, C.; Sironi, G.; Pareschi, G.; Lessio, L.; Conconi, P.

    2016-05-01

    Dual-mirror Schwarzschild-Couder (SC) telescopes are based on highly aspherical optics, and they represent a novel design in the world of very high energy astrophysics. This work addresses the realization and the qualification of the secondary mirror for an SC telescope, named ASTRI, developed in the context of the Cherenkov Telescope Array Observatory. The discussion surveys the overall development from the early design concept to the final acceptance optical tests.

  9. 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).

  10. Relationship among environmental quality variables, housing variables, and residential needs: a secondary analysis of the relationship among indoor, outdoor, and personal air (RIOPA) concentrations database

    Science.gov (United States)

    Garcia, Fausto; Shendell, Derek G.; Madrigano, Jaime

    2016-08-01

    Retrospective descriptive secondary analyses of data from relationships of indoor, outdoor, and personal air (RIOPA) study homes (in Houston, Texas; Los Angeles County, California; and, Elizabeth, New Jersey May 1999-February 2001) were conducted. Data included air exchange rates, associations between indoor and outdoor temperature and humidity, and calculated apparent temperature and humidex. Analyses examined if study homes provided optimum thermal comfort for residents during both heating and cooling seasons when compared to current American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Standards 62/62.1 and 55. Results suggested outdoor temperature, humidex, and apparent temperature during the cooling season potentially served as indicators of indoor personal exposure to parameters of thermal comfort. Outdoor temperatures, humidex, and apparent temperature during the cooling season had statistically significant predictive abilities in predicting indoor temperature. During the heating season, only humidex in Texas and combined data across study states were statistically significant, but with weaker to moderate predicative ability. The high degree of correlation between outdoor and indoor environmental variables provided support for the validity of epidemiologic studies of weather relying on temporal comparisons. Results indicated most RIOPA study residents experienced thermal comfort; however, many values indicated how several residents may have experienced some discomfort depending on clothing and indoor activities. With climate change, increases in temperature are expected, with more days of extreme heat and humidity and, potentially harsher, longer winters. Homes being built or modernized should be created with the appropriate guidelines to provide comfort for residents daily and in extreme weather events.

  11. Relationship among environmental quality variables, housing variables, and residential needs: a secondary analysis of the relationship among indoor, outdoor, and personal air (RIOPA) concentrations database

    Science.gov (United States)

    Garcia, Fausto; Shendell, Derek G.; Madrigano, Jaime

    2017-03-01

    Retrospective descriptive secondary analyses of data from relationships of indoor, outdoor, and personal air (RIOPA) study homes (in Houston, Texas; Los Angeles County, California; and, Elizabeth, New Jersey May 1999-February 2001) were conducted. Data included air exchange rates, associations between indoor and outdoor temperature and humidity, and calculated apparent temperature and humidex. Analyses examined if study homes provided optimum thermal comfort for residents during both heating and cooling seasons when compared to current American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Standards 62/62.1 and 55. Results suggested outdoor temperature, humidex, and apparent temperature during the cooling season potentially served as indicators of indoor personal exposure to parameters of thermal comfort. Outdoor temperatures, humidex, and apparent temperature during the cooling season had statistically significant predictive abilities in predicting indoor temperature. During the heating season, only humidex in Texas and combined data across study states were statistically significant, but with weaker to moderate predicative ability. The high degree of correlation between outdoor and indoor environmental variables provided support for the validity of epidemiologic studies of weather relying on temporal comparisons. Results indicated most RIOPA study residents experienced thermal comfort; however, many values indicated how several residents may have experienced some discomfort depending on clothing and indoor activities. With climate change, increases in temperature are expected, with more days of extreme heat and humidity and, potentially harsher, longer winters. Homes being built or modernized should be created with the appropriate guidelines to provide comfort for residents daily and in extreme weather events.

  12. Flow development through HP & LP turbines, Part II: Effects of the hub endwall secondary sealing air flow on the turbine's mainstream flow

    Science.gov (United States)

    Hu, Jialin; Du, Qiang; Liu, Jun; Wang, Pei; Liu, Guang; Liu, Hongrui; Du, Meimei

    2017-08-01

    Although many literatures have been focused on the underneath flow and loss mechanism, very few experiments and simulations have been done under the engines' representative working conditions or considering the real cavity structure as a whole. This paper aims at realizing the goal of design of efficient turbine and scrutinizing the velocity distribution in the vicinity of the rim seal. With the aid of numerical method, a numerical model describing the flow pattern both in the purge flow spot and within the mainstream flow path is established, fluid migration and its accompanied flow mechanism within the realistic cavity structure (with rim seal structure and considering mainstream & secondary air flow's interaction) is used to evaluate both the flow pattern and the underneath flow mechanism within the inward rotating cavity. Meanwhile, the underneath flow and loss mechanism are also studied in the current paper. The computational results show that the sealing air flow's ingestion and ejection are highly interwound with each other in both upstream and downstream flow of the rim seal. Both the down-stream blades' potential effects as well as the upstream blades' wake trajectory can bring about the ingestion of the hot gas flow within the cavity, abrupt increase of the static pressure is believed to be the main reason. Also, the results indicate that sealing air flow ejected through the rear cavity will cause unexpected loss near the outlet section of the blades in the downstream of the HP rotor passages.

  13. 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

  14. 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)

  15. A study on lithium/air secondary batteries - Stability of NASICON-type glass ceramics in acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Shimonishi, Y.; Zhang, T.; Imanishi, N.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiay-cho, Tsu, Mie 514-8507 (Japan); Johnson, P.; Sammes, N. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (United States)

    2010-09-15

    The stability of a NASICON-type lithium ion conducting solid electrolyte, Li{sub 1+x+y}Ti{sub 2-x}Al{sub x}P{sub 3-y}Si{sub y}O{sub 12} (LTAP), in acetic acid and formic acid solutions was examined. XRD patterns of the LTAP powders immersed in 100% acetic acid and formic acid at 50 C for 4 months showed no change as compared to the pristine LTAP. However, the electrical conductivity of LTAP drastically decreased. On the other hand, no significant electrical conductivity change of LTAP immersed in lithium formate saturated formic acid-water solution was observed, and the electrical conductivity of LTAP immersed in lithium acetate saturated acetic acid-water increased. Cyclic voltammogram tests suggested that acetic acid was stable up to a high potential, but formic acid decomposed under the decomposition potential of water. The acetic acid solution was considered to be a candidate for the active material in the air electrode of lithium-air rechargeable batteries. The cell reaction was considered as 2Li + 2 CH{sub 3}COOH + 1/2O{sub 2} = 2CH{sub 3}COOLi + H{sub 2}O. The energy density of this lithium-air system is calculated to be 1477 Wh kg{sup -1} from the weights of Li and CH{sub 3}COOH, and an observed open-circuit voltage of 3.69 V. (author)

  16. 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

  17. 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.

  18. 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.

  19. A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu, E-mail: yqgu@caep.cn; Zhang, Baohan [Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); and others

    2016-06-15

    During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

  20. Efficiencies of residual organic pollutants removal from secondary effluent by switching of coagulation- air flotation -filtration processes.

    Science.gov (United States)

    Huang, R; Zhang, J; Ma, L; Jiang, A; Kong, X J; Li, X K; Bao, L

    2006-01-01

    It is an essential task to remove the residual organic pollutants (ROP) from secondary effluent of a Wastewater Treatment Plant (WWTP) in wastewater reclamation and reuse processes. Four different compared flow schemes would be achieved for further purification of the secondary effluent by switching of different valves. In order to mainly remove non-biodegradable residual organic pollutants under various operating conditions, the optimum technology and economic process was obtained in the advanced purification flow scheme at a flow of 3200 m(3)/d in Harbin Wenchang WWTP. Conclusions under a lot of experiments show that: choosing the coagulation-settler plus biofilm filter for advanced purification process is reasonable; during the stable operation phase, this process showed good performance in removing the COD, BOD5, TP, NH3-N and SS; the removal rates are 50%, 39%, 67%, 50%, 80% respectively. The effluent is able to excel the requirements for wastewater reuse standards. The unit cost of the water is 0.542 yuan/m(3), which is far below the fee paid for supply water, long-distance transfer water or seawater desalination through economic analysis.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. An experimental and simulative investigation of vehicle air conditioning systems with secondary circuits; Experimentelle und simulative Untersuchung von Pkw-Klimaanlagensystemen mit Sekundaerkreislaeufen

    Energy Technology Data Exchange (ETDEWEB)

    Lemke, Julia; Lemke, Nicholas; Koehler, Juergen [Technische Univ. Braunschweig (Germany). Inst. fuer Thermodynamik

    2012-07-01

    Different concepts for the redesign of thermal systems in the vehicle are investigated in the framework of the EU project TIFFE (Thermal Systems For Fuel Economy). This is intended to improve the vehicle thermal management along with fuel savings. The background of these investigations provides new propulsion concepts such as concepts with start-stop automatic system. These propulsion concepts also require a restructuring of the vehicle air conditioning system within the overall vehicle thermal management. Thus, within the project framework the mode of operation and influence of compact refrigeration units with secondary circuits for indirect heat uptake and release at different temperature levels are investigated. The authors of the contribution under consideration report on the experimental setup of an indirect system consisting of compact refrigeration units and three secondary circuits. Furthermore, the operation and performance of the presented system are discussed on the basis of experimental results. In addition to the experimental studies, a model of the overall system and simulation results are presented. The overall system is created using the object-oriented modeling language Modelica and the component library TIL Suite.

  6. The effect of repeated preheating of dimethacrylate and silorane-based composite resins on marginal gap of class V restorations

    Directory of Open Access Journals (Sweden)

    Parnian Alizadeh Oskoee

    2017-03-01

    Full Text Available Background. One of the problems with composite resin restorations is gap formation at resin‒tooth interface. The present study evaluated the effect of preheating cycles of silorane- and dimethacrylate-based composite resins on gap formation at the gingival margins of Class V restorations. Methods. In this in vitro study, standard Class V cavities were prepared on the buccal surfaces of 48 bovine incisors. For restorative procedure, the samples were randomly divided into 2 groups based on the type of composite resin (group 1: di-methacrylate composite [Filtek Z250]; group 2: silorane composite [Filtek P90] and each group was randomly divided into 2 subgroups based on the composite temperature (A: room temperature; B: after 40 preheating cycles up to 55°C. Marginal gaps were measured using a stereomicroscope at ×40 and analyzed with two-way ANOVA. Inter- and intra-group comparisons were analyzed with post-hoc Tukey tests. Significance level was defined at P < 0.05. Results. The maximum and minimum gaps were detected in groups 1-A and 2-B, respectively. The effects of composite resin type, preheating and interactive effect of these variables on gap formation were significant (P<0.001. Post-hoc Tukey tests showed greater gap in dimethacrylate compared to silorane composite resins (P< 0.001. In each group, gap values were greater in composite resins at room temperature compared to composite resins after 40 preheating cycles (P<0.001. Conclusion. Gap formation at the gingival margins of Class V cavities decreased due to preheating of both composite re-sins. Preheating of silorane-based composites can result in the best marginal adaptation.

  7. Does Traffic-related Air Pollution Explain Associations of Aircraft and Road Traffic Noise Exposure on Children's Health and Cognition? A Secondary Analysis of the United Kingdom Sample From the RANCH Project

    OpenAIRE

    Clark, Charlotte; Crombie, Rosanna; Head, Jenny; van Kamp, Irene; Kempen, Elise van; Stansfeld, Stephen A.

    2012-01-01

    The authors examined whether air pollution at school (nitrogen dioxide) is associated with poorer child cognition and health and whether adjustment for air pollution explains or moderates previously observed associations between aircraft and road traffic noise at school and children's cognition in the 2001–2003 Road Traffic and Aircraft Noise Exposure and Children's Cognition and Health (RANCH) project. This secondary analysis of a subsample of the United Kingdom RANCH sample examined 719 chi...

  8. [Efficacy of the treatment and secondary antifungal prophylaxis in AIDS-related histoplasmosis. Experience at the Francisco J. Muñiz Infectious Diseases Hospital in Buenos Aires].

    Science.gov (United States)

    Negroni, Ricardo; Messina, Fernando; Arechavala, Alicia; Santiso, Gabriela; Bianchi, Mario

    Classic histoplasmosis is a systemic endemic mycosis due to Histoplasma capsulatum var. capsulatum. A significant reduction in the morbidity and mortality of AIDS-related histoplasmosis has been observed since the introduction of highly active antiretroviral therapy (HAART) and secondary antifungal prophylaxis. The aim of this study was to determine the current state of prognosis and treatment response of HIV-positive patients with histoplasmosis in the Francisco J. Muñiz Infectious Diseases Hospital in Buenos Aires City. A retrospective study was conducted using the demographic, clinical, immunological and treatment data of 80 patients suffering from AIDS-related histoplasmosis. Of the 80 cases studied 65 were male, the median age was 36 years, with 73.7% of the patients being drug addicts, 82.5% of the patients was not receiving HAART at diagnosis, and 58.7% of the cases had less than 50 CD4+ cells/μl at the beginning of the treatment. The initial phase of treatment consisted of intravenous amphotericin B and/or oral itraconazole for 3 months, with 78.7% of the cases showing a good clinical response. Only 26/63 patients who were discharged from hospital continued with the follow-up of the HAART, secondary prophylaxis with itraconazole or amphotericin B. Secondary prophylaxis was stopped after more than one year of HAART if the patients were asymptomatic, had two CD4+ cell counts greater than 150cells/μl, and undetectable viral loads. No relapses were observed during a two-year follow up after prophylaxis was stopped. The treatment of histoplasmosis in HIV-positive patients was effective in 78.8% of the cases. The combination of HAART and secondary antifungal prophylaxis is safe, well tolerated, and effective. The low adherence of patients to HAART and the lack of laboratory kits for rapid histoplasmosis diagnosis should be addressed in the future. The usefulness of primary antifungal prophylaxis for cryptococcosis and histoplasmosis HIV-positive patients

  9. High-time resolved measurements of biogenic and anthropogenic secondary organic aerosol precursors and products in urban air

    Science.gov (United States)

    Flores, Rosa M.; Doskey, Paul V.

    2016-04-01

    Volatile organic compounds (VOCs), which are present in the atmosphere entirely in the gas phase are directly emitted by biogenic (~1089 Tg yr-1) and anthropogenic sources (~185 Tg yr-1). However, the sources and molecular speciation of intermediate VOCs (IVOCs), which are for the most part also present almost entirely in the gas phase, are not well characterized. The VOCs and IVOCs participate in reactions that form ozone and semivolatile OC (SVOC) that partition into the aerosol phase. Formation and evolution of secondary organic aerosol (SOA) are part of a complex dynamic process that depends on the molecular speciation and concentration of VOCs, IVOCs, primary organic aerosol (POA), and the level of oxidants (NO3, OH, O3). The current lack of understanding of OA properties and their impact on radiative forcing, ecosystems, and human health is partly due to limitations of models to predict SOA production on local, regional, and global scales. More accurate forecasting of SOA production requires high-temporal resolution measurement and molecular characterization of SOA precursors and products. For the subject study, the IVOCs and aerosol-phase organic matter were collected using the high-volume sampling technique and were analyzed by multidimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS). The IVOCs included terpenes, terpenoids, n-alkanes, branched alkanes, isoprenoids, alkylbenzenes, cycloalkylbenzenes, PAH, alkyl PAH, and an unresolved complex mixture (UCM). Diurnal variations of OA species containing multiple oxygenated functionalities and selected SOA tracers of isorprene, α-pinene, toluene, cyclohexene, and n-dodecane oxidation were also quantified. The data for SOA precursor and oxidation products presented here will be useful for evaluating the ability of molecular-specific SOA models to forecast SOA production in and downwind of urban areas.

  10. 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.

  11. 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.

  12. Effects of Preheating and Storage Temperatures on Aroma Profile and Physical Properties of Citrus-Oil Emulsions.

    Science.gov (United States)

    Yang, Ying; Zhao, Chengying; Tian, Guifang; Lu, Chang; Zhao, Shaojie; Bao, Yuming; McClements, David Julian; Xiao, Hang; Zheng, Jinkai

    2017-09-06

    Citrus oils are used as good carrier oil for emulsion fabrication due to their special flavor and various health-promoting functions. In this study, the effects of preheating temperature (30, 40, 50, 60, and 70 °C) and storage temperature (4, 25, and 37 °C) on aroma profiles and physical properties of three citrus-oil (i.e., mandarin, sweet orange, and bergamot oils) emulsions were systematically investigated for the first time. The results demonstrated the significant impact of temperature on aroma profile and physical properties. The abundance of d-limonene was found to be the main factor determining the aroma of the three citrus-oil emulsions at different preheating and storage temperatures, while β-linalool and linalyl acetate were important for the aroma of bergamot oil emulsion. Preheating temperature showed a profound impact on the aroma of citrus-oil emulsions, and the aroma of different citrus oil emulsions showed different sensitivity to preheating temperature. Storage temperature was also able to alter the properties of citrus oil emulsions. The higher was the storage temperature, the more alteration of aroma and more instability of the emulsions there was, which could be attributed to the alteration of the oil components and the properties of emulsions. Among all three emulsions, bergamot-oil emulsion was the most stable and exhibited the most potent ability to preserve the aroma against high temperature. Our results would facilitate the application of citrus-oil emulsions in functional foods and beverages.

  13. 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.

  14. 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.

  15. 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.

  16. Selective Ion Transporting Polymerized Ionic Liquid Membrane Separator for Enhancing Cycle Stability and Durability in Secondary Zinc-Air Battery Systems.

    Science.gov (United States)

    Hwang, Ho Jung; Chi, Won Seok; Kwon, Ohchan; Lee, Jin Goo; Kim, Jong Hak; Shul, Yong-Gun

    2016-10-05

    Rechargeable secondary zinc-air batteries with superior cyclic stability were developed using commercial polypropylene (PP) membrane coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butylimidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane (Celguard 5550). The coat allows anionic transfer through the separator and minimizes the migration of zincate ions to the cathode compartment, which reduces electrolyte conductivity and may deteriorate catalytic activity by the formation of zinc oxide on the surface of the catalyst layer. Energy dispersive X-ray spectroscopy (EDS) data revealed the copolymer-coated separator showed less zinc element in the cathode, indicating lower zinc crossover through the membrane. Ion coupled plasma optical emission spectroscopy (ICP-OES) analysis confirmed over 96% of zincate ion crossover was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane. Electrochemical impedance spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc crossover for the untreated cell and revealed a substantial importance must be placed in zincate control.

  17. Incubation of air-pollution-control residues from secondary Pb smelter in deciduous and coniferous organic soil horizons: leachability of lead, cadmium and zinc.

    Science.gov (United States)

    Chrastný, Vladislav; Vaněk, Aleš; Komárek, Michael; Farkaš, Juraj; Drábek, Ondřej; Vokurková, Petra; Němcová, Jana

    2012-03-30

    The leachability of air-pollution-control (APC) residues from a secondary lead smelter in organic soil horizons (F and H) from a deciduous and a coniferous forest during incubation periods of 0, 3 and 6 months were compared in this work. While the concentration of Pb, Zn and Cd associated with the exchangeable/acid extractable fraction in the horizon F from the coniferous forest was higher compared to the deciduous, significantly lower concentrations in the humified horizon H was found. It is suggested that lower pH and a higher share of fulvic acids fraction (FAs) of solid phase soil organic matter (SOM) in the humified soil horizon H from the coniferous compared to the deciduous forest is responsible for a higher metal association with solid phase SOM and therefore a lower metal leaching in a soil system. From this point of view, the humified soil horizon H from the deciduous forest represents a soil system more vulnerable to Pb, Zn and Cd leaching from APC residues. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. 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

  19. 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

  20. Real-time measurements of secondary organic aerosol formation and aging from ambient air in an oxidation flow reactor in the Los Angeles area

    Science.gov (United States)

    Ortega, Amber M.; Hayes, Patrick L.; Peng, Zhe; Palm, Brett B.; Hu, Weiwei; Day, Douglas A.; Li, Rui; Cubison, Michael J.; Brune, William H.; Graus, Martin; Warneke, Carsten; Gilman, Jessica B.; Kuster, William C.; de Gouw, Joost; Gutiérrez-Montes, Cándido; Jimenez, Jose L.

    2016-06-01

    Field studies in polluted areas over the last decade have observed large formation of secondary organic aerosol (SOA) that is often poorly captured by models. The study of SOA formation using ambient data is often confounded by the effects of advection, vertical mixing, emissions, and variable degrees of photochemical aging. An oxidation flow reactor (OFR) was deployed to study SOA formation in real-time during the California Research at the Nexus of Air Quality and Climate Change (CalNex) campaign in Pasadena, CA, in 2010. A high-resolution aerosol mass spectrometer (AMS) and a scanning mobility particle sizer (SMPS) alternated sampling ambient and reactor-aged air. The reactor produced OH concentrations up to 4 orders of magnitude higher than in ambient air. OH radical concentration was continuously stepped, achieving equivalent atmospheric aging of 0.8 days-6.4 weeks in 3 min of processing every 2 h. Enhancement of organic aerosol (OA) from aging showed a maximum net SOA production between 0.8-6 days of aging with net OA mass loss beyond 2 weeks. Reactor SOA mass peaked at night, in the absence of ambient photochemistry and correlated with trimethylbenzene concentrations. Reactor SOA formation was inversely correlated with ambient SOA and Ox, which along with the short-lived volatile organic compound correlation, indicates the importance of very reactive (τOH ˜ 0.3 day) SOA precursors (most likely semivolatile and intermediate volatility species, S/IVOCs) in the Greater Los Angeles Area. Evolution of the elemental composition in the reactor was similar to trends observed in the atmosphere (O : C vs. H : C slope ˜ -0.65). Oxidation state of carbon (OSc) in reactor SOA increased steeply with age and remained elevated (OSC ˜ 2) at the highest photochemical ages probed. The ratio of OA in the reactor output to excess CO (ΔCO, ambient CO above regional background) vs. photochemical age is similar to previous studies at low to moderate ages and also extends to

  1. Does traffic-related air pollution explain associations of aircraft and road traffic noise exposure on children's health and cognition? A secondary analysis of the United Kingdom sample from the RANCH project.

    Science.gov (United States)

    Clark, Charlotte; Crombie, Rosanna; Head, Jenny; van Kamp, Irene; van Kempen, Elise; Stansfeld, Stephen A

    2012-08-15

    The authors examined whether air pollution at school (nitrogen dioxide) is associated with poorer child cognition and health and whether adjustment for air pollution explains or moderates previously observed associations between aircraft and road traffic noise at school and children's cognition in the 2001-2003 Road Traffic and Aircraft Noise Exposure and Children's Cognition and Health (RANCH) project. This secondary analysis of a subsample of the United Kingdom RANCH sample examined 719 children who were 9-10 years of age from 22 schools around London's Heathrow airport for whom air pollution data were available. Data were analyzed using multilevel modeling. Air pollution exposure levels at school were moderate, were not associated with a range of cognitive and health outcomes, and did not account for or moderate associations between noise exposure and cognition. Aircraft noise exposure at school was significantly associated with poorer recognition memory and conceptual recall memory after adjustment for nitrogen dioxide levels. Aircraft noise exposure was also associated with poorer reading comprehension and information recall memory after adjustment for nitrogen dioxide levels. Road traffic noise was not associated with cognition or health before or after adjustment for air pollution. Moderate levels of air pollution do not appear to confound associations of noise on cognition and health, but further studies of higher air pollution levels are needed.

  2. 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.

  3. Air-Stable Gold Nanoparticles Ligated by Secondary Phosphine Oxides as Catalyst for the Chemoselective Hydrogenation of Substituted Aldehydes: a Remarkable Ligand Effect.

    Science.gov (United States)

    Cano, Israel; Huertos, Miguel A; Chapman, Andrew M; Buntkowsky, Gerd; Gutmann, Torsten; Groszewicz, Pedro B; van Leeuwen, Piet W N M

    2015-06-24

    Air-stable and homogeneous gold nanoparticles (AuNPs, 1a-5a) ligated by various secondary phosphine oxides (SPOs), [R(1)R(2)P(O)H] (R(1) = Naph, R(2) = (t)Bu, L1; R(1) = R(2) = Ph, L2; R(1) = Ph, R(2) = Naph, L3; R(1) = R(2) = Et, L4; R(1) = R(2) = Cy, L5; R(1) = R(2) = (t)Bu, L6), with different electronic and steric properties were synthesized via NaBH4 reduction of the corresponding Au(I)-SPO complex. These easily accessible ligands allow the formation of well dispersed and small nanoparticles (size 1.2-2.2 nm), which were characterized by the use of a wide variety of techniques, such as transmission electron microscopy, thermogravimetric analysis, UV-vis, energy-dispersive X-ray, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), and cross polarization magic angle spinning (CP MAS) NMR spectroscopy. A pronounced ligand effect was found, and CP MAS NMR experiments enabled us to probe important differences in the polarity of the P-O bond of the SPOs coordinated to the nanoparticle surface depending on the type of substituents in the ligand. AuNPs containing aryl SPOs carry only SPO anions and are highly selective for aldehyde hydrogenation. AuNPs of similar size made with alkyl SPOs contain also SPOH, hydrogen bonded to SPO anions. As a consequence they contain less Au(I) and more Au(0), as is also evidenced by XPS. They are less selective and active in aldehyde hydrogenation and now show the typical activity of Au(0)NPs in nitro group hydrogenation.

  4. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Jones, C.B.; Smetana, F.O.

    1977-03-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using insolation levels present in North Carolina are presented. The effects of monthly variations in insolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  5. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Science.gov (United States)

    Jones, C. B.; Smetana, F. O.

    1977-01-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using isolation levels present in North Carolina are presented. The effects of monthly variations in isolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  6. 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.

  7. Surface Characteristics of Machined NiTi Shape Memory Alloy: The Effects of Cryogenic Cooling and Preheating Conditions

    Science.gov (United States)

    Kaynak, Y.; Huang, B.; Karaca, H. E.; Jawahir, I. S.

    2017-07-01

    This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish ( A f) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.

  8. 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.

  9. 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).

  10. 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.

  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. Preheating of the early universe by radiation from high-mass X-ray binaries

    Science.gov (United States)

    Sazonov, S. Yu.; Khabibullin, I. I.

    2017-04-01

    Using a reliablymeasured intrinsic (i.e., corrected for absorption effects) present-day luminosity function of high-mass X-ray binaries (HMXBs) in the 0.25-2 keV energy band per unit star formation rate, we estimate the preheating of the early Universe by soft X-rays from such systems. We find that X-ray irradiation, mainly executed by ultraluminous and supersoft ultraluminous X-ray sources with luminosity L X > 1039 erg s-1, could significantly heat ( T > T CMB, where T CMB is the temperature of the cosmic microwave background) the intergalactic medium by z 10 if the specific X-ray emissivity of the young stellar population in the early Universe was an order of magnitude higher than at the present epoch (which is possible due to the low metallicity of the first galaxies) and the soft X-ray emission from HMXBs did not suffer strong absorption within their galaxies. This makes it possible to observe the 21 cm line of neutral hydrogen in emission from redshifts z < 10.

  14. 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)

  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. 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.

  17. 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.

  18. 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

  19. 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.

    2014-01-01

    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 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. PMID:26257945

  20. 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.

  1. 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.

  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. 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.

  4. 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.

  5. Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model – Part 1: Assessing the influence of constrained multi-generational ageing

    Directory of Open Access Journals (Sweden)

    S. H. Jathar

    2015-09-01

    Full Text Available Multi-generational oxidation of volatile organic compound (VOC oxidation products can significantly alter the mass, chemical composition and properties of secondary organic aerosol (SOA compared to calculations that consider only the first few generations of oxidation reactions. However, the most commonly used state-of-the-science schemes in 3-D regional or global models that account for multi-generational oxidation (1 consider only functionalization reactions but do not consider fragmentation reactions, (2 have not been constrained to experimental data; and (3 are added on top of existing parameterizations. The incomplete description of multi-generational oxidation in these models has the potential to bias source apportionment and control calculations for SOA. In this work, we used the Statistical Oxidation Model (SOM of Cappa and Wilson (2012, constrained by experimental laboratory chamber data, to evaluate the regional implications of multi-generational oxidation considering both functionalization and fragmentation reactions. SOM was implemented into the regional UCD/CIT air quality model and applied to air quality episodes in California and the eastern US. The mass, composition and properties of SOA predicted using SOM are compared to SOA predictions generated by a traditional "two-product" model to fully investigate the impact of explicit and self-consistent accounting of multi-generational oxidation. Results show that SOA mass concentrations predicted by the UCD/CIT-SOM model are very similar to those predicted by a two-product model when both models use parameters that are derived from the same chamber data. Since the two-product model does not explicitly resolve multi-generational oxidation reactions, this finding suggests that the chamber data used to parameterize the models captures the majority of the SOA mass formation from multi-generational oxidation under the conditions tested. Consequently, the use of low and high NOx yields

  6. Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model – Part 2: Assessing the influence of vapor wall losses

    Directory of Open Access Journals (Sweden)

    C. D. Cappa

    2015-11-01

    Full Text Available The influence of losses of organic vapors to chamber walls during secondary organic aerosol (SOA formation experiments has recently been established. Here, the influence of such losses on simulated ambient SOA concentrations and properties is assessed in the UCD/CIT regional air quality model using the statistical oxidation model (SOM for SOA. The SOM was fit to laboratory chamber data both with and without accounting for vapor wall losses following the approach of Zhang et al. (2014. Two vapor wall loss scenarios are considered when fitting of SOM to chamber data to determine best-fit SOM parameters, one with "low" and one with "high" vapor wall-loss rates to approximately account for the current range of uncertainty in this process. Simulations were run using these different parameterizations (scenarios for both the southern California/South Coast Air Basin (SoCAB and the eastern United States (US. Accounting for vapor wall losses leads to substantial increases in the simulated SOA concentrations from VOCs in both domains, by factors of ~ 2–5 for the low and ~ 5–10 for the high scenario. The magnitude of the increase scales approximately inversely with the absolute SOA concentration of the no loss scenario. In SoCAB, the predicted SOA fraction of total OA increases from ~ 0.2 (no to ~ 0.5 (low and to ~ 0.7 (high, with the high vapor wall loss simulations providing best general agreement with observations. In the eastern US, the SOA fraction is large in all cases but increases further when vapor wall losses are accounted for. The total OA/ΔCO ratio represents dilution-corrected SOA concentrations. The simulated OA/ΔCO in SoCAB (specifically, at Riverside, CA is found to increase substantially during the day only for the high vapor wall loss scenario, which is consistent with observations and indicative of photochemical production of SOA. Simulated O : C atomic ratios for both SOA and for total OA increase when vapor wall losses are

  7. Preparation of in situ secondary synthesis of indoor air purification functional fabric at low temperature%低温原位二次合成法制备室内空气净化功能织物

    Institute of Scientific and Technical Information of China (English)

    王振华; 刘保江; 何瑾馨

    2011-01-01

    Air purification functional fabric with practical value was prepared using in situ secondary synthesis method at low temperature.The surface morphology of air purification functional fabric was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), atomic force microscopy (AFM) and X-ray diffraction (XRD).The good air purification ability of the treated fabric was confirmed by the degradation test of formaldehyde.In addition, the strength of TiO2 secondary synthesized cotton fabric distinctly increased,and the fabric showed excellent UV irradiation protection properties.%以低温原位二次合成法,制备了具有实用价值的空气净化功能织物.利用扫描电镜(SEM)、能谱分析(EDS)、原子力显微镜(AFM)和X射线衍射(XRD)表征空气净化功能织物表面的形态结构,并通过甲醛降解试验证明了其具有较好的空气净化能力.此外,棉织物经TiO2低温原位二次合成后强73增加明显,且具备极佳的紫外线防护特性.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Application of calcium chloride as an additive for secondary refrigerant in the air conditioning system type chiller to minimized energy consumption

    Science.gov (United States)

    Suwono, A.; Indartono, Y. S.; Irsyad, M.; Al-Afkar, I. C.

    2015-09-01

    One way to resolve the energy problem is to increase the efficiency of energy use. Air conditioning system is one of the equipment that needs to be considered, because it is the biggest energy user in commercial building sector. Research currently developing is the use of phase change materials (PCM) as thermal energy storage (TES) in the air conditioning system to reduce energy consumption. Salt hydrates have been great potential to be developed because they have been high latent heat and thermal conductivity. This study has used a salt hydrate from calcium chloride to be tested in air conditioning systems type chiller. Thermal characteristics were examined using temperature history (T-history) test and differential scanning calorimetry (DSC). The test results showed that the thermal characteristics of the salt hydrate has been a high latent heat and in accordance with the evaporator temperature. The use of salt hydrates in air conditioning system type chiller can reduce energy consumption by 51.5%.

  13. Low cost bare-plate solar air collector

    Energy Technology Data Exchange (ETDEWEB)

    Maag, W.L.; Wenzler, C.J.; Rom, F.E.; VanArsdale, D.R.

    1980-09-01

    The purpose of this project was to develop a low cost, bare-plate collector, determine its performance for a variety of climatic conditions, analyze the economics of this type of solar collector and evaluate specific applications. Two prototype collectors were designed, fabricated and installed into an instrumented test system. Tests were conducted for a period of five months. Results of the tests showed consistent operating efficiencies of 60% or greater with air preheat temperature uses up to 20/sup 0/F for one of the prototypes. The economic analyses indicated that an installed cost of between $5 and $10 per square foot would make this type of solar system economically viable. For the materials of construction and the type of fabrication and installation perceived, these costs for the bare-plate solar collector are believed to be attainable. Specific applications for preheating ventilation air for schools were evaluated and judged to be economically viable.

  14. 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.

  15. 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.

  16. Secondary pollutants or macro ecological contamination: A biotic contamination of the air. Contaminantes secundarios o contaminacion macroecologica: contaminacion abiotica de la atmosfera

    Energy Technology Data Exchange (ETDEWEB)

    Moreno Abil, O. (Catedra de Medicina Preventiva y Salud Publica Facultad de Medicina, Universidad de Granada (Spain))

    1994-01-01

    The primary and secondary contaminants are analyzed by the author. As well the effects of these contaminants by man and the ecosystem. The main topics are: (1) Photochemistry contamination (photo chemical smog) (2) Acid rain and its effects. (3) Depletion of ozone layer.

  17. Preparation of hydroxide ion conductive KOH–layered double hydroxide electrolytes for an all-solid-state iron–air secondary battery

    Directory of Open Access Journals (Sweden)

    Taku Tsuneishi

    2014-06-01

    Full Text Available Anion conductive solid electrolytes based on Mg–Al layered double hydroxide (LDH were prepared for application in an all-solid-state Fe–air battery. The ionic conductivity and the conducting ion species were evaluated from impedance and electromotive force measurements. The ion conductivity of LDH was markedly enhanced upon addition of KOH. The electromotive force in a water vapor concentration cell was similar to that of an anion-conducting polymer membrane. The KOH–LDH obtained was used as a hydroxide ion conductive electrolyte for all-solid-state Fe–air batteries. The cell performance of the Fe–air batteries was examined using a mixture of KOH–LDH and iron-oxide-supported carbon as the negative electrode.

  18. 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.

  19. 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.

  20. Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system - a human response study in hot and humid climate

    DEFF Research Database (Denmark)

    Bin, Yang; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration...

  1. Practical method for determination of air kerma by use of an ionization chamber toward construction of a secondary X-ray field to be used in clinical examination rooms.

    Science.gov (United States)

    Maehata, Itsumi; Hayashi, Hiroaki; Kimoto, Natsumi; Takegami, Kazuki; Okino, Hiroki; Kanazawa, Yuki; Tominaga, Masahide

    2016-07-01

    We propose a new practical method for the construction of an accurate secondary X-ray field using medical diagnostic X-ray equipment. For accurate measurement of the air kerma of an X-ray field, it is important to reduce and evaluate the contamination rate of scattered X-rays. To determine the rate quantitatively, we performed the following studies. First, we developed a shield box in which an ionization chamber could be set at an inner of the box to prevent detection of the X-rays scattered from the air. In addition, we made collimator plates which were placed near the X-ray source for estimation of the contamination rate by scattered X-rays from the movable diaphragm which is a component of the X-ray equipment. Then, we measured the exposure dose while changing the collimator plates, which had diameters of 25-90 mm(ϕ). The ideal value of the exposure dose was derived mathematically by extrapolation to 0 mm(ϕ). Tube voltages ranged from 40 to 130 kV. Under these irradiation conditions, we analyzed the contamination rate by the scattered X-rays. We found that the contamination rates were less than 1.7 and 2.3 %, caused by air and the movable diaphragm, respectively. The extrapolated value of the exposure dose has been determined to have an uncertainty of 0.7 %. The ionization chamber used in this study was calibrated with an accuracy of 5 %. Using this kind of ionization chamber, we can construct a secondary X-ray field with an uncertainty of 5 %.

  2. Conflicts and agreements in the process of nationalization of secondary education in Argentina during the nineteenth century. The case of the province of Buenos Aires

    Directory of Open Access Journals (Sweden)

    Susana Schoo

    2014-06-01

    Schoo, S. (2014. Conflictos y acuerdos en el proceso de nacionalización de la educación secundaria en Argentina en el siglo XIX. El caso de la provincia de Buenos Aires. Espacio, Tiempo y Educación, 1(2, pp. 113-131. doi: http://dx.doi.org/10.14516/ete.2014.001.002.005

  3. Study of sensitivity change of OSL signals from quartz and feldspars as a function of preheat temperature

    DEFF Research Database (Denmark)

    Jungner, H.; Bøtter-Jensen, L.

    1994-01-01

    Optically stimulated luminescence (OSL) signals from feldspar and quartz samples were studied using infrared (860 nm) and green light (420-575 nm) stimulation. A serious problem connected with the regeneration technique used for dating is associated with a change of OSL sensitivity to radiation...... in the couse of the measurement process. A typical effect seen is a large increase of the apparent strength of our beta source when calibrated against a gamma source. If the regeneration procedure is used, it is shown that the sensitivity increases up to similar to 50% during the measurement process...... and as a result, the equivalent dose (ED) would be underestimated. A study of sensitivity changes in feldspars and quartz was carried out with emphasis on the effect of preheat and annealing on the OSL signal. Measurement results obtained are presented, and possible elimination of errors in dating caused...

  4. 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)

  5. 二次进气固冲发动机补燃室粒子沉积数值模拟%Numerical simulation of particle deposition in solid rocket ramjet chamber with secondary air inlets

    Institute of Scientific and Technical Information of China (English)

    严聪; 张志峰; 马岑睿; 张成涛

    2014-01-01

    基于随机颗粒轨道模型和颗粒部分沉积模型,对二次进气固冲发动机补燃室壁面的粒子沉积进行了探索研究,讨论了空燃比、进气间距及流量分配比等参数对沉积的影响。结果表明,随空燃比增大,沉积区域有一个明显的前移,空燃比对沉积的影响分为两个阶段;进气间距对沉积的影响较复杂;流量分配比增大,沉积区域变化不大,但沉积总量增加。%Particle deposition in solid rocket ramjet chamber with secondary air inlets was numerically simulated based on ran-dom particle stochastic trajectory and particle partial deposition model. The effects of several parameters on deposition were dis-cussed,such as air-to-fuel ratio,inlet interval,flow distribution ratio etc.The results show that there is an obvious forward move with accretion of air-to-fuel rate,leading to two sections concerning the effects of air-to-fuel ratio.The effects of inlet interval on deposition are complex.The deposition regions change little but the deposition gross increases with the accretion of flow distribution ratio.

  6. 富邦富氧侧吹炼铜炉二次风改造生产实践%Reformation and Production Practice for Secondary Air of Fubang Oxygen-enriched Side Blown Copper Melting Furnace

    Institute of Scientific and Technical Information of China (English)

    王志超; 李东泽; 李国军

    2014-01-01

    2011年6月13日投产的富邦炉属于熔池熔炼范畴,为消除单体硫和挥发份的不利影响,富邦炉在三层铜水套侧墙上设置了二次风口,经过运行表明,该位置引入二次风极易生成炉结,给富邦炉以及硫酸系统生产带来很大隐患。富邦铜业针对这一问题进行了分析总结,提出了炉顶设置三次风口以及三次风换热的办法。改造运行至今,效果明显。%Fubang furnace coming into production on June 13 , 2011 falls under the category of bath smel-ting . In order to eliminate negative influences of free sulfur and volatile matter , Fubang furnace has set secondary tuyere on the side wall of three -layer copper water jacket . It demonstrated through operation that bringing secondary air into this position will easily create furnace accretion and bring great passivity to the production of Fubang furnace and sulfuric acid system . Fubang copper industry has made analysis and summary directing at this problem and proposed solutions to install thirdary tuyere on furnace roof and make heat transfer of thirdary air . Effect has been obvious through reformation and operation up to now .

  7. Principle Analysis on Characteristics of the Spatial Variation of Average Air Temperature in Tropical Secondary Forest Canopy Gap%热带次生林林窗平均气温空间分布特征的初步分析

    Institute of Scientific and Technical Information of China (English)

    张一平; 王进欣; 刘玉洪; 马友鑫

    2001-01-01

    Temperature measurements at the secondary forest canopy gap wereconducted in Xishuangbanna, Yunnan in fog-cool season and dry-hot season. On the basis of this measurements, the air temperature characteristics and their spatial variations in different seasons in the secondary forest canopy gap were discussed. The findings showed that there was a significant thermal effect at the gap.The effect of sunshine on the air temperature in the gap was quite different, the extreme value was on the eastern edge of gap, which may be a reason to form the gap microclimate. The results supplied a basis on further study canopy gap microclimate and the relevant ecological phenomena.

  8. 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.

  9. 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。

  10. 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.

  11. 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...

  12. 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.

  13. 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)

  14. 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.

  15. 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。

  16. 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.

  17. 燃气弹射发射筒内燃气空气二次燃烧现象研究%Study on Secondary Combustion of Jet-flow and Air Inner Tube of Gas Ej ection Launcher

    Institute of Scientific and Technical Information of China (English)

    胡晓磊; 乐贵高; 李仁凤; 马大为

    2014-01-01

    The missile launcher is subj ected to thermo-impact and ablation while secondary combustion of j et-flow and air in inner tube of gas ej ection launcher occurring.To study the secondary combustion with moving boundary inner tube,a three-order accurate MUSCL scheme was employed to solve 10-step and 9 species chemical reactions of H2/CO.The zone moving and dynamic laying method was adopted to simulate missile motion.The method was reliable by comparing with experimental results of free-j et flow impacting on plat.The effects of secondary combustion on j et field characteristic,motion law of internal traj ectory and cause for secondary combustion were studied.The results show that the secondary combustion not only affects the temperature distribution,but also the motion law of internal traj ectory.Intense chemical reaction of combustible jet-flow components with O2 in the tube results in the secondary combustion.The research provides theoretical foundations for the optimization design of gas ej ection launcher.%燃气发生器喷出的燃气射流与发射筒内空气发生二次燃烧现象对导弹发射装置产生强烈的热冲击和烧蚀。为了研究含运动边界的发射筒内二次燃烧现象,采用三阶精度 MUSCL格式求解9组分10步 H2/CO 基元化学反应动力学模型,使用域动分层网格更新方法模拟导弹运动。在与燃气自由射流冲击平台效应实验数据对比验证的基础上,分析了发射筒内二次燃烧现象对发射筒内流场和内弹道的影响以及筒内燃气空气二次燃烧产生的原因。数值结果表明:二次燃烧不仅影响温度场分布,而且影响导弹的内弹道特性;发射筒内二次燃烧现象是由于燃气发生器喷出的可燃成分与发射筒内 O2发生了强烈的化学反应导致的。研究结果对燃气弹射导弹内弹道设计提供了一定的理论基础。

  18. Design of the Secondary Heat Exchange Device for Waste Heat Recovery of Air Compressor%空压机余热回收二次换热装置的设计研究

    Institute of Scientific and Technical Information of China (English)

    岳畏畏; 陈雷田; 徐新恒; 赵新红

    2013-01-01

    随着能源紧张与环境污染等问题的出现,余热回收利用技术变得尤为重要。在余热回收技术领域中,喷油螺杆式空压机余热回收越来越受重视。余热回收装置作为空压机余热回收技术中较为重要的设备,对其进行设计研究很有必要。通过理论计算,集成了对应160 kW喷油螺杆空压机的余热回收二次换热装置,该装置可实现油温自动控制,并有效降低板换结垢的风险,对其进行热回收特性实验研究,结果表明在一次侧进出口水温70℃/50℃、二次侧进出口水温45℃/60℃工况下,热回收能量为99.85 kW,高于空压机额定功率的50%。为空压机余热回收系统设计提供参考依据,对系统施工安装起到了一定的促进作用。%The waste heat recycling technology is particularly important with the emergence of energy tension and environmental pollu-tion. The heat recovery of injection screw air compressor is more and more crucial in the waste heat recovery technology field, so it is neces-sary to research waste heat recovery device. Through the theoretical calculation, integrating the waste heat recovery of secondary heat exchange device on the injection screw air compressor with the corresponding power is 160kw. The device can realize the automatic control of oil tem-perature; meanwhile, it also can effectively reduce the risk of plate in scaling. Results from the experimental research on the heat recovery characteristics show that in the condition of import and export water temperature is 70℃/50℃ of the primary side, or import and export water temperature is 45℃/60℃of the secondary side, the heat recovery power is 99.85kW. It is higher than 50% of the air compressor power rating. This paper provides reference for air compressor heat recovery system design and also plays a certain role in promoting the system installation.

  19. 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.

  20. [Secondary dyslipidemias].

    Science.gov (United States)

    Vargová, V; Pytliak, M; Mechírová, V

    2012-03-01

    Dyslipidemias rank among the most important preventabile factors of atherogenesis and its progression. This topic is increasingly being discussed as e.g. more than 50% of Slovak population die on atherosclerotic complications. According to etiology we distinguish primary dyslipidemias with strictly genetic background and secondary ones with origin in other disease or pathological state. Secondary dyslipidemias accompany various diseases, from common (endocrinopathies, renal diseases etc) to rare ones (thesaurismosis etc.) and represents one of symptoms of these diseases. Apart from particular clinical follow up of diagnosed dysipidemias, basic screening and secondary causes as well as treatment due to updated guidelines is recuired. In this review we present the most frequent dyslipidemias of clinical practice.

  1. A full-scale study on thermal degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China.

    Science.gov (United States)

    Gao, Xingbao; Ji, Bingjing; Yan, Dahai; Huang, Qifei; Zhu, Xuemei

    2017-04-01

    Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d(-1)) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.

  2. 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.

  3. 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).

  4. Potassium Secondary Batteries.

    Science.gov (United States)

    Eftekhari, Ali; Jian, Zelang; Ji, Xiulei

    2017-02-08

    Potassium may exhibit advantages over lithium or sodium as a charge carrier in rechargeable batteries. Analogues of Prussian blue can provide millions of cyclic voltammetric cycles in aqueous electrolyte. Potassium intercalation chemistry has recently been demonstrated compatible with both graphite and nongraphitic carbons. In addition to potassium-ion batteries, potassium-O2 (or -air) and potassium-sulfur batteries are emerging. Additionally, aqueous potassium-ion batteries also exhibit high reversibility and long cycling life. Because of potentially low cost, availability of basic materials, and intriguing electrochemical behaviors, this new class of secondary batteries is attracting much attention. This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.

  5. Secondary dyslipidaemia

    African Journals Online (AJOL)

    Repro

    (e.g. metabolic syndrome, syndrome X), play a dominant role in ... change in the lipogram, the aggressive ... After dealing with the secondary cause, a risk assessment must be made by taking all .... caloric restriction for weight loss and low fat ...

  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. The effects of late homogenization conditions on the Mg2Si particle size in a slow pre-heated 6063 aluminum extrusion billet

    Science.gov (United States)

    Kayıkcı, R.; Kocaman, E.; Şirin, S.; ćolak, M.

    2015-03-01

    In order to investigate the effect of late homogenization conditions on the Mg2Si precipitation of 6063 grade extrusion billets are slow pre-heated to intentionally have large Mg2Si particle precipitation. Then the billets are water quenched to preserve this microstructure for late homogenizations. Finally billets are re-heated using two different furnace temperature as 450°C and 500°C at which temperatures the billet are held for 0.5 h, 1 h, 1.5 h, 2 h and 2.5 h periods and water quenched before being taken to metallographic examinations.

  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. 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

    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......’. 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...

  12. 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.

  13. Determination of average conversion coefficients between kerma in air and H⁎(10) using primary and secondary X-ray beams and transmitted in the diagnostic radiology energy range; Determinacao dos coeficientes de conversao medios entre kerma no ar e H*(10) usando feixes de raios-X primarios, secundarios e transmitidos na faixa de energia da radiologia diagnostica

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Josilene C.; Gonzalez, Alejandro H.L.; Costa, Paulo R. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

    2016-07-01

    Brazilian regulation establishes 1.14 Sv/Gy as unique conversion coefficient to convert air-kerma into the operational quantity ambient dose equivalent H⁎(10) disregarding its beam quality dependence. The present study computed mean conversion coefficients from primary, secondary and transmitted X-ray beams through barite mortar plates used in shielding of dedicated chest radiographic facilities in order to improve the current assessment of H⁎(10). To compute the mean conversion coefficients, the weighting of conversion coefficients corresponding to monoenergetic beams with the spectrum energy distribution in terms of air-kerma was considered. The maximum difference between the obtained conversion coefficients and the constant value recommended in national regulation is 53.4%. The conclusion based on these results is that a constant coefficient is not adequate for deriving the H⁎(10) from air-kerma measurements. (author)

  14. 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.

  15. 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

  16. Air Pollution

    Science.gov (United States)

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

  17. 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.

  18. 30 CFR 250.302 - Definitions concerning air quality.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Definitions concerning air quality. 250.302... Definitions concerning air quality. For purposes of §§ 250.303 and 250.304 of this part: Air pollutant means..., pursuant to section 109 of the Clean Air Act, national primary or secondary ambient air quality standards...

  19. Secondary aortoduodenal fistula

    Institute of Scientific and Technical Information of China (English)

    Girolamo Geraci; Franco Pisello; Francesco Li Volsi; Tiziana Facella; Lina Platia; Giuseppe Modica; Carmelo Sciumè

    2008-01-01

    Aorto-duodenal fistulae (ADF) are the most frequent aorto-enteric fistulae (80%), presenting with upper gastrointestinal bleeding. We report the first case of a man with a secondary aorto-duodenal fistula presenting with a history of persistent occlusive syndrome. A 59-year old man who underwent an aortic-bi-femoral bypass 5 years ago, presented with dyspepsia and biliary vomiting. Computed tomography scan showed in the third duodenal segment the presence of inflammatory tissue with air bubbles between the duodenum and prosthesis, adherent to the duodenum. The patient was submitted to surgery, during which the prosthesis was detached from the duodenum, the intestine failed to close and a gastro-jejunal anastomosis was performed. The post-operative course was simple, secondary ADF was a complication (0.3%-2%) of aortic surgery. Mechanical erosion of the prosthetic material into the bowel was due to the lack of interposed retroperitoneal tissue or the excessive pulsation of redundantly placed grafts or septic procedures. The third or fourth duodenal segment was most frequently involved. Diagnosis of ADF was difficult. Surgical treatment is always recommended by explorative laparotomy. ADF must be suspected whenever a patient with aortic prosthesis has digestive bleeding or unexplained obstructive syndrome. Rarely the clinical picture of ADF is subtle presenting as an obstructive syndrome and in these cases the principal goal is to effectively relieve the mechanical bowel obstruction.

  20. 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.

  1. 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)

  2. Auxiliary Heating of Geothermally Preheated Water or CO2 - A Potential Solution for Low- to Moderate-Temperature Geothermal Resources

    Science.gov (United States)

    Kong, X.; Garapati, N.; Adams, B. M.; Randolph, J.; Kuehn, T. H.; Saar, M. O.

    2015-12-01

    Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we compare over a range of parameters the net power and efficiencies of hybrid geothermal power plants that use brine or CO2 as the subsurface working fluid, that are then heated further with a secondary energy source that is unspecified here. Parameters varied include the subsurface working fluid (brine vs. CO2), geothermal reservoir depth (2.5-4.5 km), and turbine inlet temperature (200-600°C) after auxiliary heating. The hybrid power plant is numerically modeled using an iterative coupling approach of TOUGH2-ECO2N/ECO2H (Pruess, 2004) for simulation of the subsurface reservoir and Engineering Equation Solver for well bore fluid flow and surface power plant performance. We find that hybrid power plants that are CO2-based (subsurface) systems have higher thermal efficiencies than the brine based systems at low turbine inlet temperatures. Specifically, our results indicate that geothermal hybrid plants that are CO2-based are more efficient than brine-based systems when the contribution of the geothermal resource energy is higher than 48%.

  3. 采用不同二次空气时转轮式间接蒸发冷却器的性能试验研究%Experimental Study on the Performance of Rotary Wheel Indirect Evaporative Cooler using Different Secondary Air

    Institute of Scientific and Technical Information of China (English)

    孙铁柱; 黄翔; 罗绒

    2015-01-01

    In order to get the running effect of rotary wheel indirect evaporative cooler in summer ,making a series of tests in the rotary wheel heat recovery type indirect-direct evaporative cooling air conditioning prototype ,characterized by its efficiency ,cool-ing capacity ,heat transfer coefficient;At the secondary air side of rotary wheel ,two measures were taken to eliminate heat ,namely (1)Traditional sensible heat elimination;(2)Exhaust air is handled by wet film,then passes through secondary air side .Compre-hensive test results show that:the cooling capacity and efficiency of heat exchanger increase under mode 2,compared to the first mode.Within the scope of the testing the temperature drop maximum is 13℃.%在夏季,对转轮式热回收型间接-直接蒸发冷却空调样机中的转轮式间接蒸发冷却器性能进行了测试。测试中转轮式间接蒸发冷却器的二次空气采用了2种情况:一种是直接采用室内排风;另一种是经过填料式直接蒸发冷却器降温后的室内排风。对其效率、制冷量、被处理空气的温降进行了试验研究;综合测试结果表明:相比于第一种情况,转轮式热交换器在第二种情况下的制冷量和效率均有所增加;在测试的范围内温降最高可达13℃。

  4. 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.

  5. 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.

  6. Secondary combustion device for woodburning stove

    Energy Technology Data Exchange (ETDEWEB)

    Craver, R.D.

    1987-06-16

    This patent describes a wood burning stove including an exhaust flue opening, a combustion chamber for primary combustion having an access door, a support for wood to be burnt and a primary air inlet means for supplying air to support primary combustion of the wood to produce flue gases containing combustible particulate material. A conduit means for directing the flue gases is included from the combustion chamber to the flue opening in a preselected path. Also included is a secondary combustion means for burning particulate material in flue gases before flue gases pass through the exhaust flue opening. The improvement comprises: secondary combustion means including an elongated manifold extending laterally across and above the combustion chamber at a preselected position on the preselected path; a number of air openings spaced longitudinally along the manifold and facing the path of the flue gases and an air inlet means for supplying ambient; secondary combustion air to the manifold for flow from openings into the path of the flue gases in distinct jets; and a laterally elongated passageway above the manifold with upper and lower portions and defined at its upper portion by a sheet metal wall, and a layer of extremely low heat conducting insulation in the passageway. On the sheet metal wall the layer of insulation prevents appreciable conduction of heat from the passageway into the sheet metal wall and flue gases flow through the passageway and from passageway in a generally wide thin flow pattern.

  7. 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.

  8. 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。

  9. Transfer of preheat-treated SnO 2 via a sacrificial bridge-type ZnO layer for ethanol gas sensor

    KAUST Repository

    Lee, Da Hoon

    2017-08-05

    The progress in developing the microelectromechanical system (MEMS) heater-based SnO2 gas sensors was hindered by the subsequent heat treatment of the tin oxide (SnO2), nevertheless it is required to obtain excellent sensor characteristics. During the sintering process, the MEMS heater and the contact electrodes can be degraded at such a high temperature, which could reduce the sensor response and reliability. In this research, we presented a process of preheating the printed SnO2 sensing layer on top of a sacrificial bridge-type ZnO layer at such a high temperature, followed by transferring it onto the contact electrodes of sensor device by selective etching of the sacrificial ZnO layer. Therefore, the sensor device was not exposed to the high sintering temperature. The SnO2 gas sensor fabricated by the transfer process exhibited a rectangular sensing curve behavior with a rapid response of 52 s at 20 ppm ethanol concentration. In addition, reliable and repeatable sensing characteristics were obtained even at an ethanol gas concentration of 5 ppm.

  10. Hypovolemic shock after air reduction of intussusception

    Energy Technology Data Exchange (ETDEWEB)

    Royal, S.A. [University of Alabama Hospitals, Dept. of Radiology, Birmingham, AL (United States); Childrens' Hospital of Alabama, Dept. of Radiology, Birmingham, AL (United States)

    2001-03-01

    A 7-month-old white baby girl developed hypovolemic shock requiring resuscitation secondary to an air enema reduction of intussusception. The implications of this case for standardization of the management techniques in this setting are emphasized. (orig.)

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Volunteers for Air Monitoring Project (VAMP).

    Science.gov (United States)

    Oak Ridge National Lab., TN.

    An education and communication project of the Environment and Technology Assessment Program, Oak Ridge National Laboratory, Tennessee, is described in this report. The project for monitoring air dustfall resulted in the largest citizen-scientist air monitoring effort in the history of our nation. Nearly 21,000 public secondary school students and…

  16. Practice Class Curriculum Design of Secondary Vocational School based on Typical Tasks Analysis---Takes Curriculum Design of Automotive Air Conditioning Maintenance as A Example%基于典型工作任务分析的中职汽车实践类课程设计--以汽车空调故障维修课程设计为例

    Institute of Scientific and Technical Information of China (English)

    文艳宇; 韦自龙

    2014-01-01

    Practice teaching is the key link in secondary vocational education. In order to improve the quality of the automobile special-ized practice teaching, the paper takes curriculum design of automotive air conditioning maintenance as example, put forward design method of automobile professional practice curriculum combine the training mode of secondary vocational school. It will improve the stu-dents' post competence and comprehensive professional comprehensive qualities.%实践类教学是中职教学的核心环节。为提高汽车专业实践教学的质量,以汽车空调故障维修课程设计为例,结合目前中职学校的人才培养模式,提出汽车专业实践课程设计方法,全面提高学生的岗位胜任能力和职业综合素养。

  17. The Effect of the Geomagnetic Field on the Secondary Charged Particles Trajectories of Extensive Air Shower%地磁场对广延大气簇射产生的次级带电粒子的偏转效应

    Institute of Scientific and Technical Information of China (English)

    孙宝光

    2011-01-01

    用蒙特卡罗模拟的方法研究了在地磁场作用下,广延大气簇射产生的大量次级带电粒子所发生的偏转.研究发现,地磁场对从北方来的次级带电粒子的横向分布的影响比对从南方来的大,导致宇宙线观测阵列的触发效率南高于北,且随天顶角越大这种效应越明显.此外,用一次谐波和二次谐波对大量的模拟数据进行了拟合,给出了此种偏转效应对触发效率的影响程度.%In the geomagnetic field, the secondary charged particle trajectories of EAS (extensive air shower) will be distorted because of geomagnetism. In this study, the author uses Monte-Carlo simulation to investigate the effect of this distortion and concludes that the geomagnetic field leads to a stretched lateral distribution of the secondaries. This distorting effect is larger for the secondary particles of cosmic-ray coming from the north than that from the south. As a result, the trigger efficiency of the array for the former is lower than that for the latter and it becomes more evident with larger zenith angles. The simulated data is fitted by overlapping the first-harmonic and the second-harmonic to evaluate the extent of the influence of this distorting effect.

  18. 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.

  19. 40 CFR 50.8 - National primary ambient air quality standards for carbon monoxide.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.8 National primary ambient air quality standards for carbon monoxide. (a) The national primary ambient air quality standards... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary ambient air...

  20. Air Quality Monitoring: Risk-Based Choices

    Science.gov (United States)

    James, John T.

    2009-01-01

    Air monitoring is secondary to rigid control of risks to air quality. Air quality monitoring requires us to target the credible residual risks. Constraints on monitoring devices are severe. Must transition from archival to real-time, on-board monitoring. Must provide data to crew in a way that they can interpret findings. Dust management and monitoring may be a major concern for exploration class missions.

  1. Seals/Secondary Fluid Flows Workshop 1997; Volume I

    Science.gov (United States)

    Hendricks, Robert C. (Editor)

    2006-01-01

    The 1997 Conference provided discussions and data on (a) program overviews, (b) developments in seals and secondary air management systems, (c) interactive seals flows with secondary air or fluid flows and powerstream flows, (d) views of engine externals and limitations, (e) high speed engine research sealing needs and demands, and (f) a short course on engine design development margins. Sealing concepts discussed include, mechanical rim and cavity seals, leaf, finger, air/oil, rope, floating-brush, floating-T-buffer, and brush seals. Engine externals include all components of engine fluid systems, sensors and their support structures that lie within or project through the nacelle. The clean features of the nacelle belie the minefield of challenges and opportunities that lie within. Seals; Secondary air flows; Rotordynamics; Gas turbine; Aircraft; CFD; Testing; Turbomachinery

  2. Secondary Item Procurement Lead Time Study.

    Science.gov (United States)

    1984-03-01

    NONEhhhhhh % I - 15 III& 1-- -NAION&°I° oI Ai OF .° NAIU REUONF TEST CANA -~~ 7 .. SECONDARY ITEM PROCUREMENT LEAD TIME STUDY __ LOGISTICS SYSTEMS...ASSISTANT SECRETARY OF THE AIR FORCE (RD&L) DIRECTOR, DEFENSE LOGISTICS AGENCY SUBJECT: Secondary Item Procurement Lead Time Study A recent report by the...determination of procurement lead time. A plan for the study is enclosed. In order to achieve the objectives of the procurement lead time study as well as the

  3. Secondary combustion device for woodburning stove

    Energy Technology Data Exchange (ETDEWEB)

    Craver, R.D.

    1989-08-08

    This patent describes in a wood burning stove including an exhaust flue opening, a combustion chamber for primary combustion having an access door, a support for wood to be burned and a primary air inlet means for supplying air to support primary combustion of the wood to produce flue gases containing combustible particulate material, plenum means for directing the flue gases in a direction from the combustion chamber to the flue opening in a preselected path, and secondary combustion means for burning the particulate material in the flue gases before flue gases through the exhaust flue opening. The improvement comprising: the combustion chamber having a flue gas exit opening extending laterally across the top of the combustion chamber and communicating the combustion chamber with the plenum means, an elongated manifold extending laterally across and above the combustion chamber substantially coextensively with the flue gas exit opening, a number of air opening spaced longitudinally along the manifold and facing opposite the direction of the flue gases closely adjacent the flue gas exit opening, and an air inlet means for supplying ambient, secondary combustion air to the manifold for counterflow thereof from the openings into the path of the flue gases in a plurality of distinct jets.

  4. Aqueous lithium air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Visco, Steven J.; Nimon, Yevgeniy S.; De Jonghe, Lutgard C.; Petrov, Alexei; Goncharenko, Nikolay

    2017-05-23

    Aqueous Li/Air secondary battery cells are configurable to achieve high energy density and prolonged cycle life. The cells include a protected a lithium metal or alloy anode and an aqueous catholyte in a cathode compartment. The aqueous catholyte comprises an evaporative-loss resistant and/or polyprotic active compound or active agent that partakes in the discharge reaction and effectuates cathode capacity for discharge in the acidic region. This leads to improved performance including one or more of increased specific energy, improved stability on open circuit, and prolonged cycle life, as well as various methods, including a method of operating an aqueous Li/Air cell to simultaneously achieve improved energy density and prolonged cycle life.

  5. 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.

  6. Hyperaldosteronism - primary and secondary

    Science.gov (United States)

    Primary and secondary hyperaldosteronism have common symptoms, including: High blood pressure High level of calcium in the blood Fatigue Headache Muscle weakness Numbness Paralysis that comes and goes

  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. High Amplitude Secondary Mass Drive

    Energy Technology Data Exchange (ETDEWEB)

    DYCK,CHRISTOPHER WILLIAM; ALLEN,JAMES J.; HUBER,ROBERT JOHN; SNIEGOWSKI,JEFFRY J.

    2000-07-06

    In this paper we describe a high amplitude electrostatic drive for surface micromachined mechanical oscillators that may be suitable for vibratory gyroscopes. It is an advanced design of a previously reported dual mass oscillator (Dyck, et. al., 1999). The structure is a 2 degree-of-freedom, parallel-plate driven motion amplifier, termed the secondary mass drive oscillator (SMD oscillator). During each cycle the device contacts the drive plates, generating large electrostatic forces. Peak-to-peak amplitudes of 54 {micro}m have been obtained by operating the structure in air with an applied voltage of 11 V. We describe the structure, present the analysis and design equations, and show recent results that have been obtained, including frequency response data, power dissipation, and out-of- plane motion.

  9. Humanizing the Secondary School.

    Science.gov (United States)

    Hamilton, Norman K., Ed.; Saylor, J. Galen, Ed.

    These papers, presented during ASCD-sponsored conference, confront educators with issues in and alternatives for making secondary schools a more humanizing experience for students. The contributors and their articles are: Norman K. Hamilton, "Alternatives in Secondary Education"; Thornton B. Monez and Norman L. Bussiere, "The High School in Human…

  10. 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 ...

  11. 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.

  12. Temperature and Humidity Control in Air-Conditioned Buildings with lower Energy Demand and increased Indoor Air Quality

    DEFF Research Database (Denmark)

    Paul, Joachim; Martos, E. T.

    2003-01-01

    %. For indoor air temperature and humidity control, the use of an ice slurry (´Binary Ice´)was compared to conventional chilled water. The use of Binary Ice instead of chilled water makes the air handling and air distribution installation much simpler, recirculation of air becomes obsolete, and a higher portion....... Binary Ice as secondary refrigerant for air-conditioning purposes is an economical and technically feasible solution in any climate. Whatever chilled water can do in an air-conditioning installation ? Binary Ice can do it better....... of ambient air can be supplied, thus improving the indoor air quality still further. Reheating of air is not necessary when using Binary Ice. The introduction of chilled air into a room requires a different type of air outlet, however. When using Binary Ice, energy savings are high for climates with low...

  13. Teaching secondary mathematics

    CERN Document Server

    Rock, David

    2013-01-01

    Solidly grounded in up-to-date research, theory and technology,?Teaching Secondary Mathematics?is a practical, student-friendly, and popular text for secondary mathematics methods courses. It provides clear and useful approaches for mathematics teachers, and shows how concepts typically found in a secondary mathematics curriculum can be taught in a positive and encouraging way. The thoroughly revised fourth edition combines this pragmatic approach with truly innovative and integrated technology content throughout. Synthesized content between the book and comprehensive companion websi

  14. 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.

  15. Secondary amenorrhea (image)

    Science.gov (United States)

    Secondary amenorrhea is the cessation of menstrual flow for a period of 6 months or more in the absence ... as anxiety can be the root cause of amenorrhea. Treatment can range from behavior modification for excessive ...

  16. Bacteriophage secondary infection

    Institute of Scientific and Technical Information of China (English)

    Stephen; T; Abedon

    2015-01-01

    Phages are credited with having been first described in what we now, officially, are commemorating as the 100 th anniversary of their discovery. Those one-hundred years of phage history have not been lacking in excitement, controversy, and occasional convolution. One such complication is the concept of secondary infection, which can take on multiple forms with myriad consequences. The terms secondary infection and secondary adsorption, for example, can be used almost synonymously to describe virion interaction with already phage-infected bacteria, and which can result in what are described as superinfection exclusion or superinfection immunity. The phrase secondary infection also may be used equivalently to superinfection or coinfection, with each of these terms borrowed from medical microbiology, and can result in genetic exchange between phages, phage-on-phage parasitism, and various partial reductions in phage productivity that have been termed mutual exclusion, partial exclusion, or the depressor effect. Alternatively, and drawing from epidemiology, secondary infection has been used to describe phage population growth as that can occur during active phage therapy as well as upon phage contamination of industrial ferments. Here primary infections represent initial bacterial population exposure to phages while consequent phage replication can lead to additional, that is, secondary infections of what otherwise are not yet phage-infected bacteria. Here I explore the varying meanings and resultant ambiguity that has been associated with the term secondary infection. I suggest in particular that secondary infection, as distinctly different phenomena, can in multiple ways influence the success of phage-mediated biocontrol of bacteria, also known as, phage therapy.

  17. Secondary Emission Calorimeter Sensor Development

    Science.gov (United States)

    Winn, David R.; Onel, Yasar

    2012-12-01

    In a Secondary Emission electron(SEe) detector module, Secondary Emission electrons (SEe) are generated from an SE surface/cathode, when charged hadronic or electromagnetic particles, particularly shower particles, penetrate an SE sampling module placed between absorber materials (Fe, Cu, Pb, W etc) in calorimeters. The SE cathode is a thin (10-50 nm thick) film (simple metal-oxides, or other higher yield materials) on the surface of a metal plate, which serves as the entrance “window” to a compact vacuum vessel (metal or metal-ceramic); this SE film cathode is analogous to a photocathode, and the SEe are similar to p.e., which are then amplified by dynodes, also is in a PMT. SE sensor modules can make use of electrochemically etched/machined or laser-cut metal mesh dynode sheets, as large as ~30 cm square, to amplify the Secondary Emission Electrons (SEe), much like those that compact metal mesh or mesh dynode PMT's use to amplify p.e.'s. The construction requirements easier than a PMT, since the entire final assembly can be done in air; there are no critical controlled thin film depositions, cesiation or other oxygen-excluded processes or other required vacuum activation, and consequently bake-out can be a refractory temperatures; the module is sealed by normal vacuum techniques (welding or brazing or other high temperature joinings), with a simple final heated vacuum pump-out and tip-off. The modules envisioned are compact, high gain, high speed, exceptionally radiation damage resistant, rugged, and cost effective, and can be fabricated in arbitrary tileable shapes. The SE sensor module anodes can be segmented transversely to sizes appropriate to reconstruct electromagnetic cores with high precision. The GEANT4 and existing calorimeter data estimated calorimeter response performance is between 35-50 Secondary Emission electrons per GeV, in a 1 cm thick Cu absorber calorimeter, with a gain per SEe > 105 per SEe, and an e/pi<1.2. The calorimeter pulse width is

  18. 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).

  19. Secondary psychoses: an update.

    Science.gov (United States)

    Keshavan, Matcheri S; Kaneko, Yoshio

    2013-02-01

    Psychotic disorders due to a known medical illness or substance use are collectively termed secondary psychoses. In this paper, we first review the historic evolution of the concept of secondary versus primary psychosis and how this distinction supplanted the earlier misleading classification of psychoses into organic and functional. We then outline the clinical features and approach to the diagnosis of secondary psychotic disorders. Features such as atypical presentation, temporal relation to detectable medical cause, evidence of direct physiological causal relationship to the etiological agent, and the absence of evidence of a primary psychotic illness that may better explain the presentation suggest consideration of a secondary psychosis. Finally, we discuss how careful studies of secondary psychotic disorders can help elucidate the pathophysiology of primary, or idiopathic, psychotic disorders such as schizophrenia. We illustrate this issue through a discussion of three secondary psychotic disorders - psychoses associated with temporal lobe epilepsy, velocardiofacial syndrome, and N-methyl D-aspartate (NMDA) receptor encephalitis - that can, respectively, provide neuroanatomical, genetic, and neurochemical models of schizophrenia pathogenesis.

  20. Influence of secondary packing on the freezing time of chiken meat in air blast freezing tunnels Influência da embalagem secundária sobre o tempo de congelamento de carne de frango em túneis de circulação de ar forçada

    Directory of Open Access Journals (Sweden)

    Clarice de Ávila Santos

    2008-12-01

    Full Text Available Freezing of poultry cuts in continuous convective air blast tunnels is normally performed with the products protected by Low Density Polyethylene (LDPE as a primary packaging and using Corrugated Cardboard Boxes (CCB as secondary packaging. The objective of this work was to investigate the influence of these secondary packaging on the freezing of poultry cuts in continuous convective air blast tunnels. The study was performed by replacing CCB with Perforated Metal Boxes (PMB in order to remove the packaging thermal resistance. The assays, performed in a industrial plant, demonstrated that CCB used commercially for meat freezing have a high heat transfer resistance. Their replacement with PMB can lead to shorter freezing times and spatially homogeneous freezing. Reductions of up to 45% in the freezing times were observed using PMB. The plateau of the temperature curve, related to the freezing time of free water, was significantly reduced using PMB, which is accepted to lead to better product quality after thawing. As the products were protected by the LDPE films as primary packaging, their appearance were not affected. The results presented in this work indicate that replacing CBB with PMB can be an excellent alternative to reduce freezing time and improve freezing homogeneity in industrial air blast tunnels, which could also be applied to other products.O congelamento de cortes de frango em túneis convectivos é normalmente realizado com o produto envolto por filmes de polietileno de baixa densidade (PEBD, embalagem primária e acondicionado em caixas de papelão (CP, embalagem secundária. O objetivo deste trabalho foi avaliar o efeito da embalagem secundária no congelamento dos cortes de frango. Para isso, compararam-se as curvas de congelamento do produto processado acondicionado em caixas metálicas perfuradas (CMP, que praticamente eliminam a resistência térmica da embalagem secundária, com as curvas de congelamento do produto nas CP

  1. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Science.gov (United States)

    2010-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). Link to an... applicable to all areas notwithstanding the promulgation of SO2 national ambient air quality standards...

  2. Reverse Flow Engine Core Having a Ducted Fan with Integrated Secondary Flow Blades

    Science.gov (United States)

    Kisska, Michael K. (Inventor); Princen, Norman H. (Inventor); Kuehn, Mark S. (Inventor); Cosentino, Gary B. (Inventor)

    2014-01-01

    Secondary air flow is provided for a ducted fan having a reverse flow turbine engine core driving a fan blisk. The fan blisk incorporates a set of thrust fan blades extending from an outer hub and a set of integral secondary flow blades extending intermediate an inner hub and the outer hub. A nacelle provides an outer flow duct for the thrust fan blades and a secondary flow duct carries flow from the integral secondary flow blades as cooling air for components of the reverse flow turbine engine.

  3. Secondary metabolites from Ganoderma.

    Science.gov (United States)

    Baby, Sabulal; Johnson, Anil John; Govindan, Balaji

    2015-06-01

    Ganoderma is a genus of medicinal mushrooms. This review deals with secondary metabolites isolated from Ganoderma and their biological significance. Phytochemical studies over the last 40years led to the isolation of 431 secondary metabolites from various Ganoderma species. The major secondary compounds isolated are (a) C30 lanostanes (ganoderic acids), (b) C30 lanostanes (aldehydes, alcohols, esters, glycosides, lactones, ketones), (c) C27 lanostanes (lucidenic acids), (d) C27 lanostanes (alcohols, lactones, esters), (e) C24, C25 lanostanes (f) C30 pentacyclic triterpenes, (g) meroterpenoids, (h) farnesyl hydroquinones (meroterpenoids), (i) C15 sesquiterpenoids, (j) steroids, (k) alkaloids, (l) prenyl hydroquinone (m) benzofurans, (n) benzopyran-4-one derivatives and (o) benzenoid derivatives. Ganoderma lucidum is the species extensively studied for its secondary metabolites and biological activities. Ganoderma applanatum, Ganoderma colossum, Ganoderma sinense, Ganoderma cochlear, Ganoderma tsugae, Ganoderma amboinense, Ganoderma orbiforme, Ganoderma resinaceum, Ganoderma hainanense, Ganoderma concinna, Ganoderma pfeifferi, Ganoderma neo-japonicum, Ganoderma tropicum, Ganoderma australe, Ganoderma carnosum, Ganoderma fornicatum, Ganoderma lipsiense (synonym G. applanatum), Ganoderma mastoporum, Ganoderma theaecolum, Ganoderma boninense, Ganoderma capense and Ganoderma annulare are the other Ganoderma species subjected to phytochemical studies. Further phytochemical studies on Ganoderma could lead to the discovery of hitherto unknown biologically active secondary metabolites.

  4. 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...

  5. Secondary drowning in children.

    Science.gov (United States)

    Pearn, J H

    1980-10-25

    Secondary drowning (and near-drowning) is one of the post-immersion respiratory syndromes. It is defined as deterioration of pulmonary function that follows deficient gas exchange due to loss or inactivation of surfactant. A review of 94 consecutive cases of near-drowning in childhood showed that this syndrome occurred in five (5%) cases. Its onset was usually rapid and characterised by a latent period of one to 48 hours of relative respiratory well-being. It occurred more rapidly after immersion in fresh water. The two children immersed in salt water died of secondary drowning, while the three immersed in fresh water recovered completely. If it is anticipated, recognised, and treated vigorously prognosis of secondary drowning is good in fresh water cases but bad after salt water immersion.

  6. Analysis of Air Force Secondary Power Logistics Solution Contract

    Science.gov (United States)

    2010-05-21

    not impair our independence to perform audits, engagements, or any other future or ongoing reviews of Report Documentation Page Form ApprovedOMB No...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 hn I IV S!ndwrillel’lcomplaintslCX 0!Iertse...d eontr- JCt . the rcPOrilO Conwess r;,·quircd by SC"elion 346 of Pub.L. 105-261 as amcnd\\-d (IOU.S.C. 24&4 noIC). II \\\\ould be inupproplio le tor

  7. 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...

  8. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    Demands for better indoor air quality are increasing, since we spend most of our time indoors and we are more and more aware of indoor air pollution. Field studies in different parts of the world have documented that high percentage of occupants in many offices and buildings find the indoor air...... 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...... cleaning techniques. Supply air filter is one of the key components in the ventilation system. Studies have shown that used ventilation filters themselves can be a significant source of indoor air pollution with consequent impact on perceived air quality, sick building syndrome symptoms and performance...

  9. Secondary Dance Instructional Guide.

    Science.gov (United States)

    Montgomery County Public Schools, Rockville, MD. Dept. of Instructional Planning and Development.

    This manual provides guidelines for dance teachers in secondary schools. A brief statement is made on the purpose and philosophy of dance education, and activities and instructional suggestions are presented for various dance forms: (1) group dance--folk/ethnic, square dance, and social dance; (2) aerobic dance; (3) jazz dance; (4) modern dance;…

  10. [Pathophysiology of secondary hyperparathyroidism.

    Science.gov (United States)

    Kawarazaki, Hiroo

    2017-01-01

    Secondary hyperparathyroidism(SHPT)is the result of a compensatory response of the calcium phosphate homeostatic mechanism. Vitamin D deficiency and chronic kidney disease, both representative pathophysiological causes of SHPT, have been related not only to skeletal disorders but also cardiovascular diseases, ADL and QOL. This relates the importance of SHPT as a pathological cause or marker of such states.

  11. Aircraft Electric Secondary Power

    Science.gov (United States)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  12. Cosmetology. Secondary Curriculum Guide.

    Science.gov (United States)

    Moye, Michael D.; And Others

    This curriculum guide is designed to offer guidelines along with supporting resources and teaching ideas from which the local secondary instructor can extract a cosmetology curriculum that meets local needs. Following an outline of the philosophy and goals underlying state and local vocational education programs in Georgia, the purpose and…

  13. On secondary buyouts

    NARCIS (Netherlands)

    Degeorge, F.; Martin, J.; Phalippou, L.

    2015-01-01

    Private equity firms increasingly sell companies to each other in secondary buyouts (SBOs). We examine commonly expressed concerns regarding SBOs using novel and unique datasets. SBOs made by buyers under pressure to spend capital (a minority of transactions) underperform and destroy value for inves

  14. Secondary emission gas chamber

    CERN Document Server

    In'shakov, V; Skvortsov, V

    2014-01-01

    For a hadron calorimeter active element there is considered a gaseous secondary emis-sion detector (150 micron gap, 50 kV/cm). Such one-stage parallel plate chamber must be a radiation hard, fast and simple. A model of such detector has been produced, tested and some characteristics are presented.

  15. Scheduling the Secondary School.

    Science.gov (United States)

    Dempsey, Richard A.; Traverso, Henry P.

    This "how-to-do-it" manual on the intricacies of school scheduling offers both technical information and common sense advice about the process of secondary school scheduling. The first of six chapters provides an overview of scheduling; chapter 2 examines specific considerations for scheduling; chapter 3 surveys the scheduling models and their…

  16. 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)

  17. 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.

  18. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    Science.gov (United States)

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  19. Algorithms for Separation of Secondary Surveillance Radar Replies

    NARCIS (Netherlands)

    Petrochilos, N.L.R.

    2002-01-01

    Air Traffic Control (ATC) centers aim at ensuring safety of aircrafts cruising in their area. The information required to face this mission includes the data provided by primary and Secondary Surveillance Radar (SSR). The first one indicates the presence of an aircraft, whereas the second gives info

  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. 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...

  2. 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...

  3. Air Quality System (AQS)

    Science.gov (United States)

    The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements include both criteria air pollutants and hazardous air pollutants.

  4. 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...

  5. Fundamentals of Air Conditioning and Refrigeration.

    Science.gov (United States)

    Clemons, Mark

    This set of instructional materials provides secondary and postsecondary students with a state-of-the-art curriculum for the air conditioning and refrigeration industry that includes the many changes brought by new Environmental Protection Agency (EPA) regulations. Introductory materials explain the use of this publication and provide the…

  6. Stabilization of premixed lean methane-air combustion using dielectric barrier discharge with low pollutant emissions

    Science.gov (United States)

    Ono, Ryo; Ogura, Kazuaki; Mogi, Toshio

    2017-09-01

    Catalytic combustion is a promising technology to stabilize lean combustion with low pollutant emissions. Catalytic combustion has been applied to gas turbine combustors; however, some drawbacks of this technology remain to be addressed. In this work, a new concept is demonstrated to overcome the problems of catalytic combustion by using dielectric barrier discharge (DBD) instead of a catalyst. A premixed lean methane-air mixture preheated to 400 °C with an equivalence ratio of 0.45 is flowed through the DBD reactor under atmospheric pressure. Almost complete combustion is achieved with a DBD power of 0.7% of the net calorific value of the mixture. The exhaust emissions are NO = 20 ppm, NO2 = 2 ppm, CO = 2 ppm, and HC \\cong 0 ppm. This work demonstrates that DBD-assisted combustion is a potential alternative to catalytic combustion.

  7. 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

  8. 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.; hide

    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

  9. Secondary Hypertension in Pregnancy.

    Science.gov (United States)

    Malha, Line; August, Phyllis

    2015-07-01

    Hypertension is a common medical complication of pregnancy. Although 75-80 % of women with preexisting essential hypertension will have uncomplicated pregnancies, the presence of secondary forms of hypertension adds considerably to both maternal and fetal morbidity and mortality. Renovascular hypertension, pheochromocytoma, and Cushing's syndrome in particular are associated with accelerating hypertension, superimposed preeclampsia, preterm delivery, and fetal loss. Primary aldosteronism is a more heterogeneous disorder; there are well-documented cases where blood pressure and hypokalemia are improved during pregnancy due to elevated levels of progesterone. However, superimposed preeclampsia, worsening hypertension, and early delivery are also reported. When possible, secondary forms of hypertension should be diagnosed and treated prior to conception in order to avoid these complications.

  10. Secondary victims of rape

    DEFF Research Database (Denmark)

    Christiansen, Dorte Mølgaard; Bak, Rikke; Elklit, Ask

    2012-01-01

    Rape is often a very traumatic experience, which affects not only the primary victim (PV) but also his/her significant others. Studies on secondary victims of rape are few and have almost exclusively studied male partners of female rape victims. This study examined the impact of rape on 107...... secondary victims, including family members, partners, and friends of male and female rape victims. We found that many respondents found it difficult to support the PV and that their relationship with the PV was often affected by the assault. Furthermore, the sample showed significant levels...... of social support for the respondent, and feeling let down by others. The respondents were generally interested in friend-, family-, and partner-focused interventions, particularly in receiving education about how best to support a rape victim...

  11. MANDARIN SECONDARY PREDICATES

    Directory of Open Access Journals (Sweden)

    Ryosuke Shibagaki

    2010-06-01

    Full Text Available In the first part, I provide some data of secondary predicates in English and Mandarin on consequence-depictives (SUBJ-oriented and resultatives (OBJ-oriented, which adopt an intransitive verb/adjective for their secondary predicate. In the second half, I present an account of the linking issue on “resultative” compound predicates in Mandarin Chinese, building on the LFG/LMT work of Her (2007, who assumed that the argument structures of each predicate merge to give a composite structure, which determines whether a resultative sentence is semantically causative or not, and from which the arguments link to grammatical functions. I argue here that the facts require a more articulated semantics, for unlike Her’s analysis, the determination of causativity and the linking of the arguments of the two predicates is fully an issue of semantics; specifically, I argue that there are two types of secondary predicates in terms of their semantics, namely those with internally- and externally-caused changes of state (see Levin and Rappaport Hovav: 1995, McKoon and Macfarland: 2000, which are respectively “indirect-causative” and “direct-causative”; causativity should be categorised into three types, non-causative, indirect-causative, and direct causative. I further argue that the argument undergoing internally-caused change always links to Actor and that the one undergoing externally-caused change (a truly “affected” argument always links to Undergoer.

  12. 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.

  13. 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.

  14. 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.

  15. Lunar secondary craters, part K

    Science.gov (United States)

    Overbeck, V. R.; Morrison, R. H.; Wedekind, J.

    1972-01-01

    Formation of V-shaped structures surrounding the fresh Copernicus Crater and its secondary craters are reviewed, and preliminary observations of the more extensively eroded secondary crater field of Theophilus are presented. Results of laboratory simulation of secondary lunar craters to examine their effects on V-shaped ridges are also described.

  16. 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...... humidity (30, 40 and 70%) and pollution level (low and high). Most of the experiments were performed with and without facially applied airflow at elevated velocity. The importance of the use of recirculated room air and clean, cool and dry outdoor air was studied. The exposures ranged from 60. min to 235....... min. Acceptability of PAQ and freshness of the air improved when air movement was applied. The elevated air movement diminished the negative impact of increased air temperature, relative humidity and pollution level on PAQ. The degree of improvement depended on the pollution level, the temperature...

  17. Secondary Vertex Finder Algorithm

    CERN Document Server

    Heer, Sebastian; The ATLAS collaboration

    2017-01-01

    If a jet originates from a b-quark, a b-hadron is formed during the fragmentation process. In its dominant decay modes, the b-hadron decays into a c-hadron via the electroweak interaction. Both b- and c-hadrons have lifetimes long enough, to travel a few millimetres before decaying. Thus displaced vertices from b- and subsequent c-hadron decays provide a strong signature for a b-jet. Reconstructing these secondary vertices (SV) and their properties is the aim of this algorithm. The performance of this algorithm is studied with tt̄ events, requiring at least one lepton, simulated at 13 TeV.

  18. Enhancements to the hybrid pressurized air receiver (HPAR) concept in the SUNDISC cycle

    Science.gov (United States)

    Heller, Lukas; Hoffmann, Jaap

    2017-06-01

    A dual-pressure air receiver has previously been proposed as part of a hybrid receiver system preheating pressurized air in a solarized gas turbine and providing hot non-pressurized air to power the bottoming cycle of a combined cycle CSP plant. The receiver, based on a bundle of metallic tubular absorbers, was found to not be able to provide the non-pressurized air at the required temperature. Three enhancements to the basic design are presented and thermally modeled: (a) Finned absorber tubes to increase the convective heat transfer, (b) quartz glass elements to alleviate convective losses and improve the flow inside the tube bundle as well as (c) additional absorber elements behind the tube bundle. It could be shown that finned absorber tubes as well as the additional absorber elements have potential to improve the thermal performance of the receiver while a quartz glass window and flow-enhancing quartz elements could be indispensable additions to either of the other enhancements.

  19. 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....

  20. A hybrid geothermal energy conversion technology: Auxiliary heating of geothermally preheated water or CO2 - a potential solution for low-temperature resources

    Science.gov (United States)

    Saar, Martin; Garapati, Nagasree; Adams, Benjamin; Randolph, Jimmy; Kuehn, Thomas

    2016-04-01

    Safe, sustainable, and economic development of deep geothermal resources, particularly in less favourable regions, often requires employment of unconventional geothermal energy extraction and utilization methods. Often "unconventional geothermal methods" is synonymously and solely used as meaning enhanced geothermal systems, where the permeability of hot, dry rock with naturally low permeability at greater depths (4-6 km), is enhanced. Here we present an alternative unconventional geothermal energy utilization approach that uses low-temperature regions that are shallower, thereby drastically reducing drilling costs. While not a pure geothermal energy system, this hybrid approach may enable utilization of geothermal energy in many regions worldwide that can otherwise not be used for geothermal electricity generation, thereby increasing the global geothermal resource base. Moreover, in some realizations of this hybrid approach that generate carbon dioxide (CO2), the technology may be combined with carbon dioxide capture and storage (CCS) and CO2-based geothermal energy utilization, resulting in a high-efficiency (hybrid) geothermal power plant with a negative carbon footprint. Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we

  1. 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

  2. [Secondary osteoporosis in gynecology].

    Science.gov (United States)

    Taguchi, Y; Gorai, I

    1998-06-01

    Several diseases and medications are known to induce secondary osteoporosis. Among them, same situations are related to gynecological field. They include Turner's syndrome, anorexia nervosa, ovarian dysfunction, oophorectomy, GnRH agonist therapy, and osteoporosis associated with pregnancy. We briefly describe these secondary osteoporosis in this article as follows. Several studies have found osteoporosis to be a common complication of Turner's syndrome and hormone replacement therapy has been used as a possible management; in anorexic patient, low body weight, prolonged amenorrhea, early onset of anorexia nervosa, and hypercortisolism have been reported to be risks for bone demineralization; since oophorectomy which is a common intervention in gynecology leads osteoporosis, it is important to prevent osteoporosis caused by surgery as well as postmenopausal osteoporosis; GnRH agonist, which induces estrogen deficient state and affect bone mass, is commonly used as a management for endometriosis and leiomyoma of uterus; associated with pregnancy, post-pregnancy spinal osteoporosis and transient osteoporosis of the hip are clinically considered to be important and heparin therapy and magnesium sulfate therapy are commonly employed during pregnancy, affecting calcium homeostasis.

  3. Urban and Rural Air Pollution: A Cross-Age Study of School Students' Ideas.

    Science.gov (United States)

    Myers, George; Boyes, Edward; Stanisstreet, Martin

    2000-01-01

    Explores ideas about the causes and consequences of urban and rural air pollution of secondary school students aged 11-16 years (n=786) using a questionnaire. Students thought the air in towns and cities was more polluted than the air in the countryside. (Author/SAH)

  4. Air Pollution and Its Effects on an Individual's Health and Exercise Performance.

    Science.gov (United States)

    Singh, A. I. Clifford

    1988-01-01

    Air Pollution is a common environmental stressor affecting the training and competitive performance of athletes, commonly irritating the eyes, nose, and throat. The health and exercise effects of such primary and secondary air pollutants as carbon monoxide, sulfur dioxide, air particulates, ozone, and nitrogen dioxide are discussed. (CB)

  5. 76 FR 30896 - Revisions to the California State Implementation Plan, South Coast Air Quality Management District

    Science.gov (United States)

    2011-05-27

    ... proposing to approve revisions to the South Coast Air Quality Management District (SCAQMD) portion of the... overwhelmingly formed as a secondary pollutant. (South Coast 2007 Air Quality Management Plan, page ES-9... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, South Coast Air...

  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. 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...

  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. 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.

  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. A large source of low-volatility secondary organic aerosol

    DEFF Research Database (Denmark)

    Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard

    2014-01-01

    at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low......-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air...

  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. Are Ventilation Filters Degrading Indoor Air Quality in California Classrooms?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Destaillats, H.; Apte, M.G.; Destaillats,, Hugo; Fisk, Michael G. Apte and William J.

    2008-10-01

    Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects studenthealth and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air?conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone deposition in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent towhich filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.

  17. [Secondary orbital lymphoma].

    Science.gov (United States)

    Basanta, I; Sevillano, C; Álvarez, M D

    2015-09-01

    A case is presented of an 85 year-old Caucasian female with lymphoma that recurred in the orbit (secondary ocular adnexal lymphoma). The orbital tumour was a diffuse large B-cell lymphoma according to the REAL classification (Revised European-American Lymphoma Classification). Orbital lymphomas are predominantly B-cell proliferations of a variety of histological types, and most are low-grade tumours. Patients are usually middle-aged or elderly, and it is slightly more common in women. A palpable mass, proptosis and blepharoptosis are the most common signs of presentation. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  18. Secondary modern school, Koblach, Austria

    Energy Technology Data Exchange (ETDEWEB)

    Bruck, M.

    1999-07-01

    This school has eleven classrooms, as well as rooms for special lessons, a library, a three-court sports hall and several non-educational rooms. A large area (178 m{sup 2}) of single-glazed solar air collectors has been sited between the windows on the south facade. A combination of reheating of ventilation air by means of the solar air collectors, control of ventilation rates and air quality, and heat recovery from return air, considerably reduces the auxiliary heating demand. If no heating of ventilation air is needed, the air collectors are used for DHW heating. Cooling of the building during periods of hot weather is achieved by night ventilation. (author)

  19. Analysis of the influence of the multipass welding, welding preheat and welding post heat treatments on the behaviour of GMAW joints of HARDOX 400 microalloyed steel; Influencia de la tecnica de soldaduramultipasada y de los tratamientos termicos de precalentamiento y post-soldadura en el comportamiento de uniones GMAW de un acero microaleado HARDOX 400

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, A.; Miguel, V.; Coello, J.; Navarro, A.; Calatayud, A.; Manjabacas, M. C.

    2011-07-01

    The microalloyed steels may be supplied in a hardened state. In these cases, the weldability can be improved by pre-heat and/or post-heat welding treatments. In this paper, the effect of those treatments and the influence of multipass welding on GMAW joints behavior are analyzed for a Hardox 400 microalloyed steel. The microstructure evaluation of the different heat affected zones of the steel has been made and the mechanical properties of those zones are obtained for different conditions as it has been mentioned. The obtained results indicate that preheating the steel leads to a beneficial action that consists on the distance increasing from the bead to the zone in which the hardness is lowest. The post heat treatment strengthens that zone and improves the joint plasticity. This benefit is higher if the joint has been made with preheating. Multipass welding has not been found to have any advantage if it is compared to a single welding pass. (Author) 18 refs.

  20. 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.

  1. Professionalism: secondary goals

    Directory of Open Access Journals (Sweden)

    Raschke RA

    2014-06-01

    Full Text Available No abstract available. Article truncated at 150 words. Please recall my lengthy disclaimer from Part 1 of this series. In part two, we reviewed the Oath of Maimonides. We considered our profession as a sacred vocation. We defined professionalism: A good doctor can be trusted to always place his/her individual patient’s best interest first, with ability, good judgment, and a caring attitude. We determined that we should be willing to make sacrifices in our commitment to our primary goal (as critical care physicians – getting our patients and their families through their illness with as little disability and suffering as possible. Now, my second disclaimer – I am going to express my opinions from atop my Ivory Tower – as I am not in private practice, and protected a bit from the harsh reality of the business world. I am going to express my possibly somewhat naive perspective on secondary goals related to our profession. These are not necessarily bad, but ...

  2. Osteoporosis secundarias Secondary osteoporosis

    Directory of Open Access Journals (Sweden)

    J. Lafita

    2003-01-01

    Full Text Available Se denomina osteoporosis secundaria a aquella que es causada por patologías o medicaciones, distintas a la pérdida ósea explicable por la etapa postmenopáusica o envejecimiento. Las posibles patologías que pueden condicionar la pérdida de masa ósea son muy variadas: endocrinológicas, digestivas, genéticas, hematológicas, reumáticas, post-transplante, farmacológicas y un amplio grupo misceláneo. En el artículo se revisan esencialmente las causas endocrinológicas, con especial énfasis en los aspectos más controvertidos en la actualidad, seguidos de una aproximación clínica para el diagnóstico sistemático de estas patologías, frecuentes en los casos etiquetados inicialmente de osteoporosis primaria.Secondary osteoporosis is caused by pathologies or medications, differing from the bone loss explainable by the post-menopausal stage or by ageing. The possible pathologies that can condition the loss of bone mass are very varied: endocrinological, digestive, genetic, haematological, rheumatic, post-transplant, pharmacological and a wide miscellaneous group. This article essentially reviews the endocrinological causes, with special emphasis on the more controversial aspects, followed by a clinical approach for the systematic diagnosis of these pathologies, which are frequent in cases initially labelled as primary osteoporosis.

  3. 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…

  4. 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…

  5. 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

  6. Air Land Sea Bulletin

    Science.gov (United States)

    2014-11-01

    Air Land Organization, Hurricane Block, Headquarters Air Command, Royal Air Force High Wycombe, Wal- ters Ash, Buckinghamshire, UK. The reset to con...MAJ James Edwards, USA Air LTC Brian Gross, USAF LTC Blake Keil, USA Maj William Harvey , USMC MAJ Jeffrey Hazard, USA Maj Darin Lupini, USAF ALSA

  7. 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.

  8. Small Secondary Schools Administrative Manual.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Office of Public Information and Publications.

    A guideline for providing quality secondary education in situations where only a relatively small number of students are involved, this manual describes the organizational options for high school programs. The options discussed are regional high schools, area secondary schools, and local high schools. Local high schools can be further classified…

  9. Millersville University Secondary Education PDS

    Science.gov (United States)

    Marcum-Dietrich, Nanette I.; Mahoney, Tim

    2015-01-01

    Millersville University of Pennsylvania (MU) has over 150 years of proud heritage in the preparation of teachers. This article describes how the Secondary Education Professional Development School (PDS) Program model has transformed Millersville University's secondary teacher education from a traditional teacher preparation program into a dynamic…

  10. Secondary emissions during fiber laser cutting of nuclear material

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, A., E-mail: beatriz.mendes.lopez@gmail.com [IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Assunção, E. [IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); European Federation for Welding, Joining and Cutting, Porto Salvo 2740-120 (Portugal); Pires, I. [IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Quintino, L. [IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); European Federation for Welding, Joining and Cutting, Porto Salvo 2740-120 (Portugal)

    2017-04-15

    The laser process has been studied for dismantling work for more than 10 years, however there is almost no data available concerning secondary emissions generated during the process. These emissions are inevitable during the laser cutting process and can have detrimental effects in human health and in the equipment. In terms of safety, for nuclear decommissioning, is crucial to point out ways of controlling the emissions of the process. This paper gives indications about the parameters to be used in order to reduce these secondary emissions and about the influence of these parameters on the particles size distribution. In general, for producing minimal dross and fume emissions the beam focus should be placed on the surface of the material. The higher percentage of secondary emissions which present higher diameter, increases approximately linearly with the stand-off distance and with the use of low air pressure.

  11. Cellular compartmentalization of secondary metabolism

    Directory of Open Access Journals (Sweden)

    H. Corby eKistler

    2015-02-01

    Full Text Available Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g. amino acids, acetyl CoA, NADPH, enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

  12. Secondary anisotropies of the CMB

    CERN Document Server

    Aghanim, Nabila; Silk, Joseph

    2007-01-01

    The Cosmic Microwave Background fluctuations provide a powerful probe of the dark ages of the universe through the imprint of the secondary anisotropies associated with the reionisation of the universe and the growth of structure. We review the relation between the secondary anisotropies and and the primary anisotropies that are directly generated by quantum fluctuations in the very early universe. The physics of secondary fluctuations is described, with emphasis on the ionisation history and the evolution of structure. We discuss the different signatures arising from the secondary effects in terms of their induced temperature fluctuations, polarisation and statistics. The secondary anisotropies are being actively pursued at present, and we review the future and current observational status.

  13. Adventitious Roots and Secondary Metabolism

    Institute of Scientific and Technical Information of China (English)

    Hosakatte Niranjana Murthy; Eun Joo Hahn; Kee Yoeup Paek

    2008-01-01

    Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.

  14. Hanford Site Secondary Waste Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.

    2009-01-29

    Summary The U.S. Department of Energy (DOE) is making plans to dispose of 54 million gallons of radioactive tank wastes at the Hanford Site near Richland, Washington. The high-level wastes and low-activity wastes will be vitrified and placed in permanent disposal sites. Processing of the tank wastes will generate secondary wastes, including routine solid wastes and liquid process effluents, and these need to be processed and disposed of also. The Department of Energy Office of Waste Processing sponsored a meeting to develop a roadmap to outline the steps necessary to design the secondary waste forms. Representatives from DOE, the U.S. Environmental Protection Agency, the Washington State Department of Ecology, the Oregon Department of Energy, Nuclear Regulatory Commission, technical experts from the DOE national laboratories, academia, and private consultants convened in Richland, Washington, during the week of July 21-23, 2008, to participate in a workshop to identify the risks and uncertainties associated with the treatment and disposal of the secondary wastes and to develop a roadmap for addressing those risks and uncertainties. This report describes the results of the roadmap meeting in Richland. Processing of the tank wastes will generate secondary wastes, including routine solid wastes and liquid process effluents. The secondary waste roadmap workshop focused on the waste streams that contained the largest fractions of the 129I and 99Tc that the Integrated Disposal Facility risk assessment analyses were showing to have the largest contribution to the estimated IDF disposal impacts to groundwater. Thus, the roadmapping effort was to focus on the scrubber/off-gas treatment liquids with 99Tc to be sent to the Effluent Treatment Facility for treatment and solidification and the silver mordenite and carbon beds with the captured 129I to be packaged and sent to the IDF. At the highest level, the secondary waste roadmap includes elements addressing regulatory and

  15. Transition to Secondary - an Experiment in a Scottish Secondary School

    Science.gov (United States)

    Dutch, R. D.; McCall, J.

    1974-01-01

    The attainments, attitudes, personality characteristics and friendship relations of three successive year groups of children (n254, 252 and 234) were assessed towards the end of their first term in secondary school. (Editor/RK)

  16. 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

  17. Modeling Zinc-Air Batteries with Aqueous Electrolytes

    OpenAIRE

    Clark, Simon; Stamm, Johannes; Horstmann, Birger; Latz, Arnulf

    2016-01-01

    Emerging markets such as electric mobility and renewable power generation are driving a demand for high-performance electrochemical energy storage. Zinc-air batteries are a promising technology due to their high theoretical specific energy, use of cheap materials, and superior operational safety. But they suffer from effects such as poor cycling stability and self-discharge due to carbonate formation in the alkaline electrolyte. The EU Horizon 2020 project Zinc Air Secondary (ZAS!) aims to o...

  18. Air pollution episodes in Stockholm regional background air due to sources in Europe and their effects on human population

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, C. [Swedish Meteorological and Hydrological Inst., Norrkoping (Sweden)], E-mail: camilla.andersson@smhi.se; Joensson, O. [Stockholm Univ. (Sweden). Dept. of Applied Environmental Science; Forsberg, B. [Umea Univ. (Sweden), Occupational and Environmental Medicine; Johansson, C. [Environmental and Health Administration, Stockholm (Sweden)

    2013-09-01

    Using air quality measurements, we categorized air pollution according to source sectors in a rural background environment in southern Sweden based on hourly air-mass backward trajectories during 1997-2010. Concentrations of fine (PM{sub 2.5}) and sum of fine and coarse particulate matter (PM{sub 10}), accumulation mode particle number, black carbon and surface ozone were 4.0, 3.9, 4.5, 6.8 and 1.3 times higher, respectively, in air masses from the southeast as compared with those in air masses from the cleanest sector in the northwest, consistent with air-mass transport over areas with relatively high emissions of primary particulate matter (PM) and secondary PM precursors. The highest ultrafine particle numbers were associated with clean air from the northwest. We estimate that almost 7.8% and 0.6% higher premature human mortality is caused by PM{sub 2.5} and ozone exposure, respectively, when air originates from the southeast as compared with that when air originates from the northwest. Reductions of emissions in eastern Europe would reduce the highest air pollution concentrations and associated health risks. However, since air masses from the southwest are more frequent, emissions in the western part of Europe are more important for annual mean premature mortality. (orig.)

  19. 77 FR 71383 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Redesignation of the Ohio...

    Science.gov (United States)

    2012-11-30

    ... type of secondary particulate formed from SO 2 emissions from power plants and industrial facilities... applicable SIP, Federal air pollution control regulations and other permanent and enforceable emission... Review (NSR) permit programs; include criteria for stationary source emission control...

  20. Osteochondroma and secondary synovial osteochondromatosis

    Energy Technology Data Exchange (ETDEWEB)

    Peh, W.C.G. [Dept. of Diagnostic Radiology, Univ. of Hong Kong (Hong Kong); Shek, T.W.H. [Department of Pathology, Univ. of Hong Kong (Hong Kong); Davies, A.M. [Department of Diagnostic Radiology, Royal Orthopaedic Hospital, Birmingham (United Kingdom); Wong, J.W.K.; Chien, E.P. [Department of Orthopaedic Surgery, Univ. of Hong Kong (Hong Kong)

    1999-03-01

    Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period. Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding bursal and secondary SOC are reviewed. (orig.) With 7 figs., 19 refs.

  1. Accessible Capacity of Secondary Users

    CERN Document Server

    Ma, Xiao; Lin, Lei; Bai, Baoming

    2010-01-01

    A new problem formulation is presented for the Gaussian interference channels (GIFC) with two pairs of users, which are distinguished as primary users and secondary users, respectively. The primary users employ a pair of encoder and decoder that were originally designed to satisfy a given error performance requirement under the assumption that no interference exists from other users. In the case when the secondary users attempt to access the same medium, we are interested in the maximum transmission rate (defined as {\\em accessible capacity}) at which secondary users can communicate reliably without affecting the error performance requirement by the primary users under the constraint that the primary encoder (not the decoder) is kept unchanged. By modeling the primary encoder as a generalized trellis code (GTC), we are then able to treat the secondary link as a finite state channel (FSC). The relation of the accessible capacity to the capacity region of the GIFC is revealed. Upper and lower bounds on the acce...

  2. SECONDARY VERTEBRAL MALIGNOMA - RADIOLOGICAL ASPECTS

    Directory of Open Access Journals (Sweden)

    Rade R. Babic

    2003-04-01

    Full Text Available Vertebral bones are among the bones of osteoarticular system which are most often affected by secondary malignoma.In the paper we present radiodiagnostical aspects of secondary malignoma in vertebral bones by conventional radiograms, and we illustrate and describe radiodiagnostic characteristics of the osteoplastic, osteolytic and osteolytic-osteoplastic metastasis.Author conclude that the diagnosis of metastasis in vertebral bones is always important for TNM classification, and that their character often points to the primary locus of malignoma.

  3. Secondary liquefaction in ethanol production

    DEFF Research Database (Denmark)

    2007-01-01

    The invention relates to a method of producing ethanol by fermentation, said method comprising a secondary liquefaction step in the presence of a themostable acid alpha-amylase or, a themostable maltogenic acid alpha-amylase.......The invention relates to a method of producing ethanol by fermentation, said method comprising a secondary liquefaction step in the presence of a themostable acid alpha-amylase or, a themostable maltogenic acid alpha-amylase....

  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. 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...

  6. 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...

  7. 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 ...

  8. 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...

  9. 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....

  10. 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

  11. 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....

  12. A Cold Model Aerodynamical Test of Air-Staged Combustion in a Tangential Firing Utility Boiler

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui-juan; HUI Shi-en; ZHOU Qu-lan

    2007-01-01

    The purpose of this paper is to present the flow field in the 300MW tangential firing utility boiler that used the Low NOx Concentric Firing System (LNCFS). Using the method of cold isothermal simulation ensures the geometric and boundary condition similarity. At the same time the condition of self-modeling is met. The experimental results show that the mixture of primary air and secondary air becomes slower, the average turbulence magnitude of the main combustion zone becomes less and the relative diameter of the tangential firing enlarges when the secondary air deflection angle increases. When the velocity pressure ratio of the secondary air to the primary air (p2/p1) enlarges, the mixture of the secondary air and the primary air becomes stronger, the average turbulence magnitude of the main combustion zone increases, and the relative diameter of the tangential firing becomes larger. Because the over fire air (OFA) laid out near the wall has a powerful penetration, the relative diameter of the tangential firing on the section of the OFA is very little, but the average turbulence magnitude is great. When the velocity pressure ratio of the OFA to the primary air pOFA/p1 increases, the relative diameter of the tangential firing on the section of the OFA grows little, the average turbulence magnitude becomes larger and the penetration of the OFA becomes more powerful.

  13. 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.

  14. 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.…

  15. Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

    Science.gov (United States)

    Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

    2017-03-01

    In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

  16. 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....

  17. 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....... 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...... higher than what can be achieved today with the commonly used total volume air distribution principles....

  18. Numerical Simulation of Subcooled Boiling in Secondary Circuit of Steam Generator%蒸汽发生器二回路过冷沸腾的数值模拟

    Institute of Scientific and Technical Information of China (English)

    张小英; 丁斐; 陈佳跃

    2013-01-01

    为深入研究核电蒸汽发生器二回路侧汽液两相的沸腾传热和流动特性,采用RPI模型对过冷沸腾区域壁面的热流分配进行划分,以此修正CFD程序中的两流体模型,并利用文献中的实验结果验证了修正后模型的适定性.最后以大亚湾压水堆核电站为例,采用该模型对蒸汽发生器内二回路预热段单元通道内的过冷沸腾进行计算,获得了通道内流体空泡份额、速度、温度、热流量分配等的分布情况.%In order to deeply investigate the vapor-liquid two-phase boiling heat transfer and flow characteristics in the secondary circuit of steam generator,the wall heat flux partition in the subcooled boiling region was divided by using the RPI model for revising the two-fluid model of the CFD (Computational Fluid Dynamics) program,and some published experimental results were used to validate the reliability of the revised mode.Moreover,a case study on the steam generator of Daya Bay PWR (Pressurized Water Reactor) nuclear power plant was carried out,in which the subcooled boiling in the preheating part of the secondary circuit was computed with the revised model,and the distributions of fluid void fraction,speed,temperature and heat flux partition in the preheating part were all obtained.

  19. 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)

  20. 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)

  1. Sequestration of Soil Carbon as Secondary Carbonates (Invited)

    Science.gov (United States)

    Lal, R.

    2013-12-01

    Rattan Lal Carbon Management and Sequestration Center The Ohio State University Columbus, OH 43210 USA Abstract World soils, the major carbon (C) reservoir among the terrestrial pools, contain soil organic C (SOC) and soil inorganic C (SIC). The SIC pool is predominant in soils of arid and semi-arid regions. These regions cover a land area of about 4.9x109 ha. The SIC pool in soils containing calcic and petrocalcic horizons is estimated at about 695-748 Pg (Pg = 1015 g = 1 gigaton) to 1-m depth. There are two types of carbonates. Lithogenic or primary carbonates are formed from weathering of carbonaceous rocks. Pedogenic or secondary carbonates are formed by dissolution of CO2 in the soil air to form carbonic acid and precipitation as carbonates of Ca+2 or Mg+2. It is the availability of Ca+2 or Mg+2 from outside the ecosystem that is essential to sequester atmospheric CO2. Common among outside sources of Ca+2 or Mg+2 are irrigation water, aerial deposition, sea breeze, fertilizers, manure and other amendments. The decomposition of SOC and root respiration may increase the partial pressure of CO2 in the soil air and lead to the formation of HCO_3^- upon dissolution in H20. Precipitation of secondary carbonates may result from decreased partial pressure of CO2 in the sub-soil, increased concentration of Ca+2, Mg+2 and HCO_3^- in soil solution, and decreased soil moisture content by evapotranspiration. Transport of bicarbonates in irrigated soils and subsequent precipitation above the ground water (calcrete), activity of termites and other soil fauna, and management of urban soils lead to formation of secondary carbonates. On a geologic time scale, weathering of silicate minerals and transport of the by-products into the ocean is a geological process of sequestration of atmospheric CO2. Factors affecting formation of secondary carbonates include land use, and soil and crop management including application of biosolids, irrigation and the quality of irrigation water

  2. 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...

  3. 77 FR 45992 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Indiana; Michigan...

    Science.gov (United States)

    2012-08-02

    ... requirements. The Bureau of Air Management houses an active Statewide Compliance and Enforcement Team that... that contribute to secondary PM 2.5 formation. One of these requirements is for NSR permits to address pollutants responsible for the secondary formation of PM 2.5, otherwise known as precursors. In the 2008...

  4. Priority One: Environment. Air Pollution and Your Health, Teacher's Guide.

    Science.gov (United States)

    McCutcheon, Patricia; And Others

    This teaching guide is designed to be used with secondary school students and the unit Air Pollution and Your Health. Material for the teacher includes the following: (1) an introduction to the unit; (2) a discussion of the sections of the unit; (3) instructional objectives; (4) suggestions for use of filmstrips, worksheets, reference materials,…

  5. [Cancer as secondary immunodeficiency. Review].

    Science.gov (United States)

    Vargas-Camaño, María Eugenia; Guido-Bayardo, Ricardo Leopoldo; Martínez-Aguilar, Nora Ernestina; Castrejón-Vázquez, María Isabel

    2016-01-01

    Secondary immunodeficiencys, previously presented in immunocompetent individuals. The lack of primary or secondary response to the presence of a foreign antigen, in the case of infections is a sentinel data in the diagnosis of immunodeficiency (can be primary or secondary), in the case of a self antigen may generate the presence of Cancer. Cancer has shown an increase in the prevalence and incidence globally. Most current medical treatments in cancer are focused primarily on immunomodulatory actions (immunosuppression / immune stimulation or both). Knowledge of key concepts from the perspective of innate and acquired immunity lead to cancer development, engaging immune surveillance and escape mechanisms of this that contribute to better understand the origin, behavior and treatment of neoplasm's. These treatments can cause immunological disorders such as allergy, anaphylaxis, lack of response immunogenicity care fields specialist in allergy and clinical immunology.

  6. Renal secondary hyperparathyroidism in dogs.

    Science.gov (United States)

    Stillion, Jenefer R; Ritt, Michelle G

    2009-06-01

    The parathyroid glands secrete parathyroid hormone (PTH), which is important for maintaining calcium homeostasis. Parathyroid gland hyperplasia and subsequent hyperparathyroidism can occur secondary to chronic renal failure in dogs, resulting in significant alterations in calcium metabolism. Renal secondary hyperparathyroidism is a complex, multifactorial syndrome that involves changes in circulating levels of calcium, PTH, phosphorus, and 1,25-dihydroxycholecalciferol (calcitriol). An increased PTH level can have deleterious effects, including soft tissue mineralization, fibrous osteodystrophy, bone marrow suppression, urolithiasis, and neuropathy. Dietary phosphorus restriction, intestinal phosphate binders, and calcitriol supplementation may slow the progression of renal disease and decrease PTH concentrations in animals with secondary hyperparathyroidism; however, the prognosis for these animals is guarded to poor.

  7. Causes of secondary pediatric osteoporosis.

    Science.gov (United States)

    Bianchi, Maria Luisa

    2013-06-01

    Secondary osteoporosis is increasingly observed in both adult and pediatric patients affected by many heterogeneous diseases. Most forms of secondary osteoporosis derive from one or more of the following causes: malnutrition, malabsorption, immobilization and/or reduced mechanical load, vitamin D deficiency, chronic inflammation, hormonal derangements, and chronic use of glucocorticoids and other drugs. Considering the lack of symptoms in the early phases, both the risk and the presence of secondary osteoporosis tend to be underestimated, and as a consequence, appropriate prevention/treatment measures are often delayed or not taken at all. Failure to accumulate an appropriate bone mass for gender and age or to build an architecturally "strong" bone must always be suspected when a child or adolescent presents with frequent and/or low-trauma fractures, chronic bone pain, or an incidental finding of "osteopenia" on plain X-rays. Known risk factors must always be considered.

  8. [Methylphenidate and secondary Raynaud's phenomenon].

    Science.gov (United States)

    Iglesias Otero, M; Portela Romero, M; Bugarín González, R; Ventura Victoria, M A

    2013-09-01

    Raynaud's phenomenon is a clinical disease characterized by episodic attacks of vasoconstriction of the arteries and arterioles of the extremities such as fingers and toes, sometimes the ears and nose, in response to cold or emotional stimuli. A classic attack is the pallor of the distal extremity, followed by cyanosis and redness, accompanied by paresthesia, usually as heat. When it occurs without apparent cause is called primary Raynaud's phenomenon. When associated with other disease, is called secondary Raynaud's phenomenon. The secondary table is associated with increased frequency of rheumatic diseases of collagen. They can also present certain drugs that cause vasoconstriction, such as ergotamine, beta-adrenergic antagonists, contraception and sympathomimetic drugs. Regarding the latter, we present a case of Raynaud's phenomenon secondary to methylphenidate in a 14 years.

  9. Summarizing primary and secondary effects

    DEFF Research Database (Denmark)

    Karlson, Kristian Bernt

    2013-01-01

    Current methods for decomposing class differentials in educational decisions into primary and secondary effects produce many parameters, rendering them ill-equipped for parsimonious comparisons across countries or birth cohorts. This paper develops a parametric method that provides an optimal...... summary of primary and secondary effects across discrete class origins. Under the testable assumption that the pattern of effects of class origins on academic ability is proportional to the pattern of effects of class origins on educational choice net of academic ability, the method returns a single...... summary measure. Applying the method to two cohorts born in the UK in 1958 and 1970 suggests that––even with increasing overall inequality of educational opportunity––the relative contribution of secondary effects to class differentials in A-level completion has changed little between the two cohorts....

  10. Local Air Quality Conditions and Forecasts

    Science.gov (United States)

    ... Monitor Location Archived Maps by Region Canada Air Quality Air Quality on Google Earth Links A-Z About AirNow AirNow International Air Quality Action Days / Alerts AirCompare Air Quality Index (AQI) ...

  11. 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.

  12. Romania: Secondary Education and Training. Secondary Education Series.

    Science.gov (United States)

    Fretwell, David H.; Wheeler, Antony

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  13. Russia: Secondary Education and Training. Secondary Education Series.

    Science.gov (United States)

    Fretwell, David H.; Wheeler, Antony

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  14. Poland: Secondary Education and Training. Secondary Education Series.

    Science.gov (United States)

    Fretwell, David H.; Wheeler, Antony

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  15. Hungary: Secondary Education and Training. Secondary Education Series.

    Science.gov (United States)

    Fretwell, David H.; Wheeler, Antony

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  16. China: Challenges of Secondary Education. Secondary Education Series.

    Science.gov (United States)

    Liang, Xiaoyan

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  17. Turkey: Secondary Education and Training. Secondary Education Series.

    Science.gov (United States)

    Fretwell, David H.; Wheeler, Antony

    The World Bank has been assisting the efforts of developing countries to reform secondary education systems for more than 35 years. During this period, the context and imperatives for education reform have changed considerably due to various factors such as globalization of the world economy and the impact of new technologies. This paper is one of…

  18. Function-related Secondary User Needs and Secondary Data

    African Journals Online (AJOL)

    Riette Ruthven

    This leads to a redefinition of all the concepts examined. It is also explained why .... tion, in turn, decides the presence, form and content of primary data. Whatever ... skip". As regards secondary needs related to the user's linguistic and subject- .... MTLF. By determining the function of a dictionary and the scope of all classes.

  19. 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.)

  20. Saving energy in the make-up air unit (MAU) for semiconductor clean rooms in subtropical areas

    Energy Technology Data Exchange (ETDEWEB)

    Tsao, Jhy-Ming; Hu, Shih-Cheng [Department of Energy and Refrigerating Air-Conditioning Engineering, National Taipei University of Technology. 1, Sec. 3, Chung-Hsiao E. Rd. Taipei 106 (China); Chan, David Yih-Liang; Hsu, Rich Tsung-Chi; Lee, Jane Car-Cheng [Energy and Environment Research Labs, Industrial Technology Research Institute Bldg 51, 195, Sec. 4, Chung Hsing Rd, Chutung, Hinchu 106 Taiwan (China)

    2008-07-01

    The energy requirements to cool, dehumidify, preheat and/or humidify outdoor air are significant in the make-up air unit (MAU) of clean room air-conditioning systems, and can represent 30% to 65% of the total thermal energy required to maintain a clean room environment. Because of these high-energy requirements, cost-effective means to reduce energy costs can influence unit production costs. Reducing or displacing mechanical cooling or electrical heating requirements can achieve the greatest opportunity for significant energy savings. This paper, therefore, aims to improve the energy performance of the MAU system by properly arranging compositions of components of a typical MAU applied in a semiconductor clean room. Explicitly, we investigated the influence of various factors including the fan location (draft-through type vs. push-through type), chilled water system (single-chilled water temperature system vs. two chilled water temperature system) and reheating scheme (electrical heating vs. hot water provided by heat recovery chiller). The result shows that the draw-through type accompanied by two chilled water temperature system with heat recovery function exhibits the lowest electrical power consumption. (author)

  1. The Characteristics of Long-range Transboundary Inorganic Secondary Aerosols in Northeast Asia

    Science.gov (United States)

    Kim, Y. J.; Carmichael, G. R.; Woo, J. H.; Qiang, Z.

    2014-12-01

    Recurrent particle matter episodes greatly influence air quality in Northeast Asia. According to many studies, a major reason is long-range transport of air pollutant. Large amount of emission of chemical compounds aggravate air pollution in the region. Emitted air pollutants mainly come from industrialized regions along the East China coast. It can be transported over downwind region by the prevailing westerlies. The long-rang transported fine particle certainly attributes to air quality in downwind region, but there are many unknowns on the quantity, transport pattern, and secondary aerosol production mechanism despite the fact with many studies have been performed. Major contributors of PM2.5 are inorganic secondary aerosols, sulfate, nitrate and ammonium, in Korea. Especially high relative contributions of inorganic secondary aerosols appear for westerly wind cases. The main pathway of production of inorganic secondary aerosols is produced by converting from SO2 and NOx during the long-range transport but the contribution varies dramatically depending on season and wind pattern. Sulfate is consistently the primary contributor of PM2.5 still now but we should more concern nitrate because that NOx emissions of China is increasing steeply since 2000 by leading powerplant, industry, and transport, despite downward trend of SO2. In order to better understand regional air quality modeling of the long-range transport, international study, MICS-Asia phase III, has been initiated with many researchers. We will present chemical characteristics of PM2.5 long-range transport during westerly wind cases focused on secondary aerosol, tracking their transport pattern, and production pathway. Results using CMAQ with the modeling domain covering Northeast and Southeast China, Korea, and Japan with 15km resolution will be discussed.

  2. Clean Air for Anchorage and Fairbanks: Curriculum for Grades 7-12.

    Science.gov (United States)

    South East Regional Resource Center, Juneau, AK.

    Ten lessons on air and air pollution comprise this guide for secondary school teachers. Among the topics addressed are pollutants, health effects, weather inversions, personal involvement, and automobile emissions. Particular emphasis is placed upon problems in Alaskan cities. Lesson plans contain a materials list, background information,…

  3. On the introduction of secondary fingerprint classification

    CSIR Research Space (South Africa)

    Msiza, IS

    2011-07-01

    Full Text Available of the fingerprint is extremely acute, hence ?x is extremely small. Figure 5 depicts all three A secondary fingerprint classes. 108 State of the Art in Biometrics On the Introduction of Secondary Fingerprint Classification 5 (a) A-1 secondary class (b) A-2... secondary class (c) A-3 secondary class Fig. 5. Fingerprint patterns that determine the A secondary classes. A-1 class: 0 cores & 0 deltas; A-2 class: equation 1; and A-3 class: equation 2 2.3 Left Loop (LL) primary class and its secondary classes...

  4. 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.

  5. 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.

  6. 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.

  7. Portugal's Secondary School Modernisation Programme

    Science.gov (United States)

    Heitor, Teresa V.; Freire da Silva, Jose M. R.

    2009-01-01

    The aim of the Secondary School Modernisation Programme, being implemented in Portugal by "Parque Escolar, EPE", is based on the pursuit of quality and makes Portuguese education a potential international benchmark. This paper discusses the strategies adopted to reorganise school spaces. It describes the conceptual model and highlights…

  8. Portugal's Secondary School Modernisation Programme

    Science.gov (United States)

    Heitor, Teresa V.; Freire da Silva, Jose M. R.

    2009-01-01

    The aim of the Secondary School Modernisation Programme, being implemented in Portugal by "Parque Escolar, EPE", is based on the pursuit of quality and makes Portuguese education a potential international benchmark. This paper discusses the strategies adopted to reorganise school spaces. It describes the conceptual model and highlights the…

  9. Teacher's Guide to Secondary Mathematics.

    Science.gov (United States)

    Duval County Schools, Jacksonville, FL.

    This is a teacher's guide to secondary school mathematics. Developed for use in the Duval County Public Schools, Jacksonville, Florida. Areas of mathematics covered are algebra, analysis, calculus, computer literacy, computer science, geometry, analytic geometry, general mathematics, consumer mathematics, pre-algebra, probability and statistics,…

  10. Summarizing primary and secondary effects

    DEFF Research Database (Denmark)

    Karlson, Kristian Bernt

    2013-01-01

    summary of primary and secondary effects across discrete class origins. Under the testable assumption that the pattern of effects of class origins on academic ability is proportional to the pattern of effects of class origins on educational choice net of academic ability, the method returns a single...

  11. Primary expectations of secondary metabolites

    Science.gov (United States)

    My program examines the plant secondary metabolites (i.e. phenolics) important for human health, and which impart the organoleptic properties that are quality indicators for fresh and processed foods. Consumer expectations such as appearance, taste, or texture influence their purchasing decisions; a...

  12. Guidance in the Secondary School

    Science.gov (United States)

    Kumar, V. Jurist Lional

    2010-01-01

    Secondary School Students face a lot of problems in their body as well as in mind due to puberty that tends to adolescence stage. Adolescence has peculiar characters of their own. They need proper Guidance and Counselling to tackle their own problems. Guidance is described as a counselling service to assist the individual in achieving self…

  13. Secondary Science and Social Responsibility

    Science.gov (United States)

    Both, Roger

    1973-01-01

    Argues for an increased emphasis on teaching the history of science in secondary school science courses. A greater understanding of the nature of the scientific enterprise in the past should make students more aware of the interrelationships of science and society. (JR)

  14. Managing Secondary Schools in China.

    Science.gov (United States)

    Bush, Tony; Coleman, Marianne; Xiaohong, Si

    1998-01-01

    Explores how secondary schools in China are managed using the results from case studies at three schools in the Shaanxi province while simultaneously comparing the findings to schools in Britain. Addresses the structure of the schools, the principal's role, the school's decision-making, and management techniques for the curriculum, finance, and…

  15. Complex Variables in Secondary Schools

    Science.gov (United States)

    Dwyer, Jerry; Moskal, Barbara; Duke, Billy; Wilhelm, Jennifer

    2007-01-01

    This article describes the work of outreach mathematicians introducing the topic of complex variables to eighth and ninth grade students (13- to 15-year-olds) in the US. Complex variables is an area of mathematics that is not typically studied at secondary level. The authors developed seven lessons designed to stimulate students' interest in…

  16. The secondary metabolite bioinformatics portal

    DEFF Research Database (Denmark)

    Weber, Tilmann; Kim, Hyun Uk

    2016-01-01

    . In this context, this review gives a summary of tools and databases that currently are available to mine, identify and characterize natural product biosynthesis pathways and their producers based on ‘omics data. A web portal called Secondary Metabolite Bioinformatics Portal (SMBP at http...

  17. Endocrine causes of secondary hypertension.

    Science.gov (United States)

    Sica, Domenic A

    2008-07-01

    Secondary hypertension is common in clinical practice if a broad definition is applied. Various patterns of hypertension exist in the patient with an endocrine source of their disease, including new-onset hypertension in a previously normotensive individual, a loss of blood pressure control in a patient with previously well-controlled blood pressure, and/or labile blood pressure in the setting of either of these 2 patterns. A thorough history and physical exam, which can rule out concomitant medications, alcohol intake, and over-the-counter medication use, is an important prerequisite to the workup for endocrine causes of hypertension. Endocrine forms of secondary hypertension, such as pheochromocytoma and Cushing's disease, are extremely uncommon. Conversely, primary aldosteronism now occurs with sufficient frequency so as to be considered "top of the list" for secondary endocrine causes in otherwise difficult-to-treat or resistant hypertension. Primary aldosteronism can be insidious in its presentation since a supposed hallmark finding, hypokalemia, may be variable in its presentation. It is important to identify secondary causes of hypertension that are endocrine in nature because surgical intervention may result in correction or substantial improvement of the hypertension.

  18. Primary and secondary stabbing headache.

    Science.gov (United States)

    Robbins, Matthew S; Evans, Randolph W

    2015-04-01

    Eight out of the 33 cases of primary stabbing headache seen in a general neurology clinic (40% have headache as their chief complaint) in the last 3.5 years are presented. The epidemiology, association with other primary headache disorders, secondary associations, testing, and treatment of primary stabbing headache are reviewed.

  19. Defining secondary progressive multiple sclerosis.

    Science.gov (United States)

    Lorscheider, Johannes; Buzzard, Katherine; Jokubaitis, Vilija; Spelman, Tim; Havrdova, Eva; Horakova, Dana; Trojano, Maria; Izquierdo, Guillermo; Girard, Marc; Duquette, Pierre; Prat, Alexandre; Lugaresi, Alessandra; Grand'Maison, François; Grammond, Pierre; Hupperts, Raymond; Alroughani, Raed; Sola, Patrizia; Boz, Cavit; Pucci, Eugenio; Lechner-Scott, Jeanette; Bergamaschi, Roberto; Oreja-Guevara, Celia; Iuliano, Gerardo; Van Pesch, Vincent; Granella, Franco; Ramo-Tello, Cristina; Spitaleri, Daniele; Petersen, Thor; Slee, Mark; Verheul, Freek; Ampapa, Radek; Amato, Maria Pia; McCombe, Pamela; Vucic, Steve; Sánchez Menoyo, José Luis; Cristiano, Edgardo; Barnett, Michael H; Hodgkinson, Suzanne; Olascoaga, Javier; Saladino, Maria Laura; Gray, Orla; Shaw, Cameron; Moore, Fraser; Butzkueven, Helmut; Kalincik, Tomas

    2016-09-01

    A number of studies have been conducted with the onset of secondary progressive multiple sclerosis as an inclusion criterion or an outcome of interest. However, a standardized objective definition of secondary progressive multiple sclerosis has been lacking. The aim of this work was to evaluate the accuracy and feasibility of an objective definition for secondary progressive multiple sclerosis, to enable comparability of future research studies. Using MSBase, a large, prospectively acquired, global cohort study, we analysed the accuracy of 576 data-derived onset definitions for secondary progressive multiple sclerosis and first compared these to a consensus opinion of three neurologists. All definitions were then evaluated against 5-year disease outcomes post-assignment of secondary progressive multiple sclerosis: sustained disability, subsequent sustained progression, positive disability trajectory, and accumulation of severe disability. The five best performing definitions were further investigated for their timeliness and overall disability burden. A total of 17 356 patients were analysed. The best definition included a 3-strata progression magnitude in the absence of a relapse, confirmed after 3 months within the leading Functional System and required an Expanded Disability Status Scale step ≥4 and pyramidal score ≥2. It reached an accuracy of 87% compared to the consensus diagnosis. Seventy-eight per cent of the identified patients showed a positive disability trajectory and 70% reached significant disability after 5 years. The time until half of all patients were diagnosed was 32.6 years (95% confidence interval 32-33.6) after disease onset compared with the physicians' diagnosis at 36 (35-39) years. The identified patients experienced a greater disease burden [median annualized area under the disability-time curve 4.7 (quartiles 3.6, 6.0)] versus non-progressive patients [1.8 (1.2, 1.9)]. This objective definition of secondary progressive multiple

  20. Solar Air Sampler

    Science.gov (United States)

    1981-01-01

    Nation's first solar-cell-powered air monitoring station was installed at Liberty State Park, New Jersey. Jointly sponsored by state agencies and the Department of Energy, system includes display which describes its operation to park visitors. Unit samples air every sixth day for a period of 24 hours. Air is forced through a glass filter, then is removed each week for examination by the New Jersey Bureau of Air Pollution. During the day, solar cells provide total power for the sampling equipment. Excess energy is stored in a bank of lead-acid batteries for use when needed.