WorldWideScience

Sample records for air preheaters

  1. Prediction of flame formation in highly preheated air combustion

    International Nuclear Information System (INIS)

    Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

  2. Biomass gasification with preheated air: Energy and exergy analysis

    Directory of Open Access Journals (Sweden)

    Karamarkovic Rade M.

    2012-01-01

    Full Text Available Due to the irreversibilities that occur during biomass gasification, gasifiers are usually the least efficient units in the systems for production of heat, electricity, or other biofuels. Internal thermal energy exchange is responsible for a part of these irreversibilities and can be reduced by the use of preheated air as a gasifying medium. The focus of the paper is biomass gasification in the whole range of gasification temperatures by the use of air preheated with product gas sensible heat. The energetic and exergetic analyses are carried with a typical ash-free biomass feed represented by CH1.4O0.59N0.0017 at 1 and 10 bar pressure. The tool for the analyses is already validated model extended with a heat exchanger model. For every 200 K of air preheating, the average decrease of the amount of air required for complete biomass gasification is 1.3% of the amount required for its stoichiometric combustion. The air preheated to the gasification temperature on the average increases the lower heating value of the product gas by 13.6%, as well as energetic and exergetic efficiencies of the process. The optimal air preheating temperature is the one that causes gasification to take place at the point where all carbon is consumed. It exists only if the amount of preheated air is less than the amount of air at ambient temperature required for complete gasification at a given pressure. Exergy losses in the heat exchanger, where the product gas preheats air could be reduced by two-stage preheating.

  3. Analysis and application of variable conductance heat pipe air preheater

    Science.gov (United States)

    Shi, Chengming; Wang, Yang; Liao, Quan; Yang, Ying

    2011-09-01

    The heat transfer analysis of variable conductance heat pipe air preheater was carried out. The temperature transfer matrix was obtained for the air preheater that comprises several discrete heat transfer units with same or different heat transfer surface area in a parallel or counter flow mode. By using the temperature transfer matrix, the outlet fluid temperatures could be easily calculated for a given air preheater and inlet fluid temperatures. The active length of condenser in a variable conductance heat pipe is determined according to the flat interface model. With the same initial conditions, the comparisons between variable conductance heat-pipe air preheater and regular heat pipe air preheater has been analyzed and tested in terms of heat pipe wall temperature, heat transfer surface area and outlet fluid temperatures. Based on the real industrial applications, it has been confirmed that the variable conductance heat pipe air preheater has excellent performance of anti-corrosion and anti-ash-deposition especially at the variable working condition and the sulfur coal (5%-6% mass fraction of sulfur) condition.

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

    OpenAIRE

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

    2014-01-01

    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...

  5. A High Temperature Regenerative Air Preheater for MHD Power Plants

    International Nuclear Information System (INIS)

    In order to attain sufficiently high flame temperatures so that combustion products can be used as a working fluid in an MHD generator, the combustion air must either be enriched with oxygen or preheated to relatively high temperatures. Ideally the regenerative preheat of the combustion air should be as high as possible. However, the air preheat temperature is limited by the availability and cost of high temperature materials, together with the feasibility of operating with seed impurities in the combustion products as well as of recovery of the seed added. The paper proposes the use of a high temperature heat exchanger system consisting of storage-type heaters with magnesium oxide as the bed matrix material. It contains a description of experimental apparatus to study such a system, and it presents experimental results. The system operates on the principle of successive heating and cooling of the bed matrix material by the hot combustion products and combustion air, respectively. The conditions governing condensation and evaporation of seed are described. During the heating of the bed, seed will at first condense when the gas is cooled below the dew point temperature for seed in the gas, but the condensed seed will evaporate again when the pebble surface temperature is brought above the equilibrium temperature for the vapour pressure of seed in the gas. With proper operation the temperature of the bed matrix material can be varied during normal cycling of the bed, such that the bed cleans itself of seed. The seed is then transported through the bed with the gas and recovered in electrostatic precipitators at the end of the system. Previous experiments with a pilot electrostatic precipitator have demonstrated that very high collection efficiencies can be obtained. The chemistry of seed and compatibility of using magnesium oxide as pebble and bed refractory material with alkali metal laden gas and condensed seed have been investigated. The experiments conducted have

  6. 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.

  7. 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.

  8. Effect of air preheat temperature on the MILD combustion of syngas

    International Nuclear Information System (INIS)

    Highlights: • MILD combustion is achieved with reaction zone covering the entire combustion chamber. • Critical equivalence ratio for the occurrence of MILD combustion is identified. • MILD regime can be established for syngas fuel under air preheating conditions. - Abstract: The effect of air preheat temperature on MILD (Moderate or Intense Low-oxygen Dilution) combustion of coal-derived syngas was examined in parallel jet forward flow combustor. The results were presented on flow field using numerical simulations and on global flame signatures, OH∗ radicals distribution and exhaust emissions using experiments. The discrete and high speed air/fuel injections into the combustor is necessary for the establishment of MILD conditions, because they cause strong gas recirculation and form large mixing region between the air and fuel jets. The critical equivalence ratio above which MILD combustion occurred was identified. The MILD regime was established for syngas fuel under air preheating conditions with lean operational limit and suppressed NOx and CO emissions. In the MILD combustion regime, the air preheating resulted in higher NOx but lower CO emissions, while the increase of equivalence ratio led to the increase of NOx and the decrease of CO emissions

  9. 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.

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

    OpenAIRE

    Zakariya Kaneesamkandi

    2014-01-01

    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 ...

  11. 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.

  12. The effect of air preheating in a biomass CFB gasifier using ASPEN Plus simulation

    Energy Technology Data Exchange (ETDEWEB)

    Doherty, Wayne; Reynolds, Anthony; Kennedy, David [Department of Mechanical Engineering, Dublin Institute of Technology, Bolton Street, Dublin 1 (Ireland)

    2009-09-15

    In the context of climate change, efficiency and energy security, biomass gasification is likely to play an important role. Circulating fluidised bed (CFB) technology was selected for the current study. The objective of this research is to develop a computer model of a CFB biomass gasifier that can predict gasifier performance under various operating conditions. An original model was developed using ASPEN Plus. The model is based on Gibbs free energy minimisation. The restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification reactions. The model predicts syn-gas composition, conversion efficiency and heating values in good agreement with experimental data. Operating parameters were varied over a wide range. Parameters such as equivalence ratio (ER), temperature, air preheating, biomass moisture and steam injection were found to influence syn-gas composition, heating value, and conversion efficiency. The results indicate an ER and temperature range over which hydrogen (H{sub 2}) and carbon monoxide (CO) are maximised, which in turn ensures a high heating value and cold gas efficiency (CGE). Gas heating value was found to decrease with ER. Air preheating increases H{sub 2} and CO production, which increases gas heating value and CGE. Air preheating is more effective at low ERs. A critical air temperature exists after which additional preheating has little influence. Steam has better reactivity than fuel bound moisture. Increasing moisture degrades performance therefore the input fuel should be pre-dried. Steam injection should be employed if a H{sub 2} rich syn-gas is desired. (author)

  13. The effect of air preheating in a biomass CFB gasifier using ASPEN Plus simulation

    International Nuclear Information System (INIS)

    In the context of climate change, efficiency and energy security, biomass gasification is likely to play an important role. Circulating fluidised bed (CFB) technology was selected for the current study. The objective of this research is to develop a computer model of a CFB biomass gasifier that can predict gasifier performance under various operating conditions. An original model was developed using ASPEN Plus. The model is based on Gibbs free energy minimisation. The restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification reactions. The model predicts syn-gas composition, conversion efficiency and heating values in good agreement with experimental data. Operating parameters were varied over a wide range. Parameters such as equivalence ratio (ER), temperature, air preheating, biomass moisture and steam injection were found to influence syn-gas composition, heating value, and conversion efficiency. The results indicate an ER and temperature range over which hydrogen (H2) and carbon monoxide (CO) are maximised, which in turn ensures a high heating value and cold gas efficiency (CGE). Gas heating value was found to decrease with ER. Air preheating increases H2 and CO production, which increases gas heating value and CGE. Air preheating is more effective at low ERs. A critical air temperature exists after which additional preheating has little influence. Steam has better reactivity than fuel bound moisture. Increasing moisture degrades performance therefore the input fuel should be pre-dried. Steam injection should be employed if a H2 rich syn-gas is desired. (author)

  14. Instrumentation strategies for energy conservation in broiler barns with ventilation air solar pre-heaters

    Energy Technology Data Exchange (ETDEWEB)

    Cordeau, Sebastien; Barrington, Suzelle [Department of Bioresource Engineering, Macdonald Campus of McGill University, 21 111 Lakeshore, Ste Anne de Bellevue, Quebec H9X 3V9 (Canada)

    2010-08-15

    At the present consumption rate, world fossil-fuel reserves are expected to be depleted by 2050 unless their consumption is optimized and supplemented with renewable energy sources. The objective of this project was to evaluate the performance of a simple data acquisition system installed to conduct an energy balance and identify energy saving strategies in two commercial broilers barns with ventilation air solar pre-heaters. Located near Montreal, Canada, the two identical barns were instrumented for inside and outside air conditions, ventilation rate and energy recovery by the solar air pre-heaters. Whereas the temperature, relative humidity and radiation sensors were reliable, inside air temperature stratification complicated energy balance analyses and broiler heat production rate calculations. Lack of room air mixing resulted in the loss of 25 and 15% of the generated heater load and recovered solar energy. The proper monitoring of all environmental conditions required their measurement every 5 rather than 20 min. Instead of using a data transmission service found to be unreliable in rural areas, all data loggers were downloaded onto a portable computer every 45 days during regular instrument maintenance. Accordingly, room air mixing is recommended to facilitate energy balance studies and improve the efficient use of heating energies. (author)

  15. 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.

  16. Effect of air preheating and fuel moisture on combustion characteristics of corn straw in a fixed bed

    International Nuclear Information System (INIS)

    Experiments were carried out on a one-dimensional bench combustion tests rig. The effect of air preheating and moisture level in the fuel on combustion characteristics of corn straw was investigated. The bed temperature distribution and the mass loss of fuel and gas components such as O2, CO, CO2 and NO were measured in the bed. The average burning rate and ignition front propagation velocity increased with increasing primary air preheating temperature. The total burning time was shorter under the higher primary air preheating temperature and the higher primary air preheating temperature produced a lower ignition front flame temperature in the bed. The variation of the flue gas O2, CO and CO2 concentrations with time was more intensive at a higher primary air preheating temperature during the ignition front propagation period and the char oxidation period. With the increase of the fuel moisture, average burning rate and ignition front propagation velocity decreased. As the fuel moisture was less than 30.71%, with the increase of the fuel moisture, residual mass loss rate decreased and ignition front flame temperature increased at a fixed air flow rate. Drier fuels resulted in fuel-rich combustion and higher CO concentration. The NO concentration decreased with increasing the moisture level in the fuel

  17. 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.

  18. Hydrogen autoignition in a turbulent jet with preheated co-flow air

    Energy Technology Data Exchange (ETDEWEB)

    Echekki, Tarek; Gupta, Kamlesh G. [Department of Mechanical and Aerospace Engineering, North Carolina State University, 2601 Stinson Drive - Campus Box 7910, Raleigh, NC 27695-7910 (United States)

    2009-10-15

    The autoignition of hydrogen in a turbulent jet with preheated air is studied computationally using the stand-alone one-dimensional turbulence (ODT) model. The simulations are based on varying the jet Reynolds number and the mixture pressure. Also, computations are carried out for homogeneous autoignition at different mixture fractions and the same two pressure conditions considered for the jet simulations. The simulations show that autoignition is delayed in the jet configuration relative to the earliest autoignition events in homogeneous mixtures. This delay is primarily due to the presence of scalar dissipation associated with the scalar mixing layer in the jet configuration as well as with the presence of turbulent stirring. Turbulence plays additional roles in the subsequent stages of the autoignition process. Pressure effects also are present during the autoignition process and the subsequent high-temperature combustion stages. These effects may be attributed primarily to the sensitivity of the autoignition delay time to the mixture conditions and the role of pressure and air preheating on molecular transport properties. The overall trends are such that turbulence increases autoignition delay times and accordingly the ignition length and pressure further contribute to this delay. (author)

  19. The Effects of Air Preheating and Fuel/Air Inlet Diameter on the Characteristics of Vortex Flame

    Directory of Open Access Journals (Sweden)

    Mostafa Khaleghi

    2015-01-01

    Full Text Available The effects of fuel/air inlet diameter as well as air preheating on the flame stability, temperature distribution, pollutant formation, and combustion characteristics of a lab-scaled asymmetric vortex flame have been investigated. A three-dimensional steady-state finite volume solver has been used to solve the governing and energy equations. The solver uses a first-order upwind scheme to discretize the governing equations in the space. The semi-implicit method for pressure linked equations has been applied to couple the pressure to the velocity terms. Several turbulence models were applied to predict the flame temperature and it was found that k-ε RNG has given the best results in accordance with the experimental results. The results reveal that the inlet air diameter can enhance the thermal properties and reduce the NOx emission while the inlet fuel diameter has less significant impact. Increasing diameters are accompanied with a pressure drop. It was found that preheating the air and fuel would significantly affect the flame temperature and NOx emission with constant mass flow rate.

  20. Experimental and Modeling Investigation of the Effect of Air Preheat on the Formation of NOx in an RQL Combustor

    Science.gov (United States)

    Samuelsen, G. S.; Brouwer, J.; Vardakas, M. A.; Holderman, J. D.

    2012-01-01

    The Rich-burn/Quick-mix/Lean-burn (RQL) combustor concept has been proposed to minimize the formation of oxides of nitrogen (NOx) in gas turbine systems. The success of this low-NOx combustor strategy is dependent upon the links between the formation of NOx, inlet air preheat temperature, and the mixing of the jet air and fuel-rich streams. Chemical equilibrium and kinetics modeling calculations and experiments were performed to further understand NOx emissions in an RQL combustor. The results indicate that as the temperature at the inlet to the mixing zone increases (due to preheating and/or operating conditions) the fuel-rich zone equivalence ratio must be increased to achieve minimum NOx formation in the primary zone of the combustor. The chemical kinetics model illustrates that there is sufficient residence time to produce NOx at concentrations that agree well with the NOx measurements. Air preheat was found to have very little effect on mixing, but preheating the air did increase NOx emissions significantly. By understanding the mechanisms governing NOx formation and the temperature dependence of key reactions in the RQL combustor, a strategy can be devised to further reduce NOx emissions using the RQL concept.

  1. 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.

  2. Modelling of flow rate in a photovoltaic-driven roof slate-based solar ventilation air preheating system

    International Nuclear Information System (INIS)

    This paper describes the modelling of flow rate in a photovoltaic (PV) driven, roof slate based solar system for preheating ventilation air in cold climates. The system consists of a photovoltaic driven, attic mounted fan, which draws air through the spaces between the warm slates and delivers it through a metallic flexible duct into a house. A model for predicting the flow rate of air as a function of irradiance and ambient temperature is developed based on the measured performance of the different components of the system. Considering all experimental sources of error, the model predicts the flow rate of air with a maximum error of 12%. The model is validated for different combinations of components in a roof section constructed at Napier University in Edinburgh. The predicted flow rates are within 10% of the measured values. The model is extended so that it can be applied for different locations and different roof tilts and orientations. A future paper will make use of the model developed herein for system optimisation based on maximum monthly volume of preheated ventilation air delivered. The model will also be used to investigate the effectiveness of PV driven, roof slate based systems as solar air heaters

  3. Impacts of dynamic interactions on the predicted thermal performance of earth–air heat exchangers for preheating, cooling and ventilation of buildings

    OpenAIRE

    Gan, Guohui

    2015-01-01

    Earth–air tunnel ventilation is an energy efficient ventilation technique that makes use of relatively stable soil temperature in shallow ground for preheating and cooling of supply air to a building. During operation, an earth–air heat exchanger interacts with the soil and atmosphere and the performance varies with the soil and atmospheric conditions. A computer program has been developed for modelling of coupled heat and moisture transfer in soil and for simulation of the dynamic thermal pe...

  4. Vibration Analysis and Control for Combined Air-preheater of Coking Furnace%焦化加热炉空气预热器振动及减振

    Institute of Scientific and Technical Information of China (English)

    颜祥富; 侯杰; 龙运国

    2013-01-01

    The combined air-preheater produces strong vibration when the coking furnace is working. In this paper, it was pointed out that the resonance caused by Carmen vortex is the main reason for the strong vibration of the air-preheater. To avoid the resonance, the Carmen vortex frequency of the heat-transfer-tube was adjusted so that it would not coincide with the natural frequency of the chamber any more. Through the improvement, the vibration of the air-proheater was eliminated, and the normal operation of the preheater was resumed.%  焦化装置组合式空气预热器试运行时产生强烈振动,对组合式空气预热器产生振动的原因进行分析,卡门涡流是预热器产生振动的主要原因。提出合理的消振方案,通过改造,该预热器消除了振动,恢复了正常的运行。

  5. Heat recovery from a boiler exhaust to pre-heat air to a spray dryer. A demonstration project at BIP Chemicals Ltd

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    This demonstration project at BIP Chemicals Ltd., is one of a package of projects being funded by the Energy Efficiency Office of the Department of Energy, under the Energy Efficiency Demonstration Scheme. It involves the recovery of waste heat to pre-heat spray dryer inlet air. It is estimated that the adoption of the technology within the UK will lead to energy savings worth Pound 1.5M/year by 1990. The project at BIP demonstrates the use of a heat pipe exchanger to recover the heat from a boiler exhaust in order to pre-heat the inlet air. Details of the performance of the exchanger and the resulting energy and cost savings at the spray dryer are given, and factors affecting the savings are discussed. This project has shown that the use of a separate boiler exhaust, even if located some 60 m from the dryer, is a practical and cost-effective means of improving the efficiency of a spray dryer.

  6. Gravitational waves in preheating

    OpenAIRE

    Tilley, Daniel; Maartens, Roy

    2000-01-01

    We study the evolution of gravitational waves through the preheating era that follows inflation. The oscillating inflaton drives parametric resonant growth of scalar field fluctuations, and although super-Hubble tensor modes are not strongly amplified, they do carry an imprint of preheating. This is clearly seen in the Weyl tensor, which provides a covariant description of gravitational waves.

  7. 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

  8. Dust collection from flue gas at coal-fired power stations revamping of electrostatic precipitators and air preheaters

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, J. [Apparatebau Rothemuehle, Brandt & Kritzler GmbH, Wenden-Rothemuehle (Germany)

    1997-12-31

    While it is currently fashionable to talk only about reduction of SO{sub 2} and NO{sub x}, dust removal is also a vital part of air pollution control. Many stations have pre-existing electrostatic precipitators but many of those are inadequate by modern standards. The old electrostatic precipitators need not be abandoned as most can be upgraded by readjustment and retrofitting new components. Examples of precipitator upgrading in Eastern Germany are described. Regenerating air heaters with sealings can reduce leakages and improve performance at low cost. This may even rebate the need for a precipitator upgrade.

  9. Chaos and Preheating

    CERN Document Server

    Jorás, S E; Jor\\'as, Sergio E.

    2003-01-01

    We show evidence for a relationship between chaos and parametric resonance both in a classical system and in the semiclassical process of particle creation. We apply our considerations in a toy model for preheating after inflation.

  10. Experimental investigation and optimisation of burner systems for glass melting ends with regenerative air preheating. Final report; Experimentelle Untersuchung und Optimierung von Brennersystemen fuer Glasschmelzwannen mit regenerativer Luftvorwaermung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Scherello, A.; Flamme, M.; Kremer, H.

    2000-02-15

    The project comprised experiments on burner systems for glass melting ends with regenerative air preheating for the purpose of optimisation. The experimental set-up was to reflect realistic conditions. In the first stage of the investigations, modern burner systems were installed in a GWI test facility and investigated. [German] Ziel des oben genannten Forschungsvorhabens war die Durchfuehrung experimenteller Untersuchungen von Brennersystemen fuer Glasschmelzwannen mit regenerativer Luftvorwaermung sowie deren Optimierung. Dazu war es notwendig, einen experimentellen Aufbau zu realisieren, mit dessen Hilfe die Stroemungs-, Mischungs- und Umsetzungsphaenomene von Glasschmelzoefen realistisch nachgestellt und aussagekraeftige Untersuchungen durchgefuehrt werden koennen. In einem ersten Untersuchungsschritt wurden moderne Brennerlanzen an der GWI-Versuchsanlage installiert und untersucht. (orig.)

  11. The Common Problems of and Optimization for the Motor and Control Circuit of Air Preheater%空气预热器电机及控制回路的常见问题和优化措施

    Institute of Scientific and Technical Information of China (English)

    兰建辉

    2016-01-01

    This paper analyzes the problems and risks existing in the electrical aspect of the air preheater produced by Haodunhua Company, and puts forward an improvement scheme, which can guarantee the table operation of the unit(one motor of air preheater is in maintenance at outage while another one motor is in normal operation) through strengthening the sealing performance of control cabinet and optimizing its control circuit.%分析了豪顿华公司制造的空气预热器电气方面存在的问题隐患,并提出了改造方案。通过加强控制柜的密封性能和对其控制回路的优化,保障了空预器的主辅电机在一台停电检修时另一台正常工作,确保了机组的稳定运行。

  12. Gravitational-wave mediated preheating

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Stephon [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Marcianò, Antonino [Center for Field Theory and Particle Physics & Department of Physics, Fudan University, 200433 Shanghai (China); Yunes, Nicolás [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States)

    2015-04-09

    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.

  13. 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.

  14. Gravitational-wave mediated preheating

    International Nuclear Information System (INIS)

    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

  15. Preheated Advection Dominated Accretion Flow

    CERN Document Server

    Park, M G; Park, Myeong-Gu; Ostriker, Jeremiah P.

    2001-01-01

    All high temperature accretion solutions including ADAF are physically thick, so outgoing radiation interacts with the incoming flow, sharing as much or more resemblance with classical spherical accretion flows as with disk flows. We examine this interaction for the popular ADAF case. We find that without allowance for Compton preheating, a very restricted domain of ADAF solution is permitted and with Compton preheating included a new high temperature PADAF branch appears in the solution space. In the absence of preheating, high temperature flows do not exist when the mass accretion rate mdot == Mdot c^2 / L_E >~ 10^-1.5. Below this mass accretion rate, a roughly conical region around the hole cannot sustain high temperature ions and electrons for all flows having mdot >~ 10^-4, which may lead to a funnel possibly filled with a tenuous hot outgoing wind. If the flow starts at large radii with the usual equilibrium temperature ~10^4 K, the critical mass accretion rate is much lower, mdot exist. However, above ...

  16. Noise and Dissipation During Preheating

    CERN Document Server

    Jorás, S E; Joras, Sergio E.; Ramos, Rudnei O.

    2002-01-01

    We study the consequences of noise and dissipation for parametric resonance during preheating. The effective equations of motion for the inflaton and the radiation field are obtained and shown to present self-consistent noise and dissipation terms. The equations exhibit the usual parametric resonance phenomenon, allowing for exponential amplification of the radiation modes inside the instability bands. By focusing on the dimension of the border of those bands we explicitly show that they are fractal, indicating the strong dependence of the outcome in the initial conditions. The simultaneous effect of noise and dissipation to the fractality of the borders are then examined.

  17. Preheating after Techni-inflation

    CERN Document Server

    Channuie, Phongpichit

    2016-01-01

    We study the details of preheating in an inflationary scenario in which the lightest composite state stemming from the minimal walking technicolor theory plays the role of the inflaton. For model of inflation, the effective theory couples non-minimally to gravity. We examine a resonant particle production of an additional scalar field coupled minimally to a spacetime curvature as well as to a composite inflaton field. In particular, we find that this process can be characterized by the Mathieu equation. Interestingly, we discover that broad resonances can be typically achieved and potentially efficient in our model.

  18. Rugged Preheaters For Vacuum Plasma Spraying

    Science.gov (United States)

    Woodford, William H.; Mckechnie, Timothy N.; Sander, Lewis D.; Power, Christopher A.; Sander, Heather L.; Nguyen, Dalton D.

    1994-01-01

    Electric preheater units built to ensure large workpieces to be coated with metals by vacuum plasma spraying heated uniformly to requisite high temperatures by time plasma torch arrives. Units similar to electrical-resistance ribbon heaters in toasters and in some small portable electric "space" heaters. Nichrome resistance-heating ribbons wrapped around ceramic insulating spools on rings and on plates. Round workpiece placed in middle of ring preheater. Plate preheaters stacked as needed near workpiece.

  19. Optimal Substrate Preheating Model for Thermal Spray Deposition of Thermosets onto Polymer Matrix Composites

    Science.gov (United States)

    Ivosevic, M.; Knight, R.; Kalidindi, S. R.; Palmese, G. R.; Tsurikov, A.; Sutter, J. K.

    2003-01-01

    High velocity oxy-fuel (HVOF) sprayed, functionally graded polyimide/WC-Co composite coatings on polymer matrix composites (PMC's) are being investigated for applications in turbine engine technologies. This requires that the polyimide, used as the matrix material, be fully crosslinked during deposition in order to maximize its engineering properties. The rapid heating and cooling nature of the HVOF spray process and the high heat flux through the coating into the substrate typically do not allow sufficient time at temperature for curing of the thermoset. It was hypothesized that external substrate preheating might enhance the deposition behavior and curing reaction during the thermal spraying of polyimide thermosets. A simple analytical process model for the deposition of thermosetting polyimide onto polymer matrix composites by HVOF thermal spray technology has been developed. The model incorporates various heat transfer mechanisms and enables surface temperature profiles of the coating to be simulated, primarily as a function of substrate preheating temperature. Four cases were modeled: (i) no substrate preheating; (ii) substrates electrically preheated from the rear; (iii) substrates preheated by hot air from the front face; and (iv) substrates electrically preheated from the rear and by hot air from the front.

  20. Products cooked in preheated versus non-preheated ovens. Baking times, calculated energy consumption, and product quality compared.

    Science.gov (United States)

    Odland, D; Davis, C

    1982-08-01

    Plain muffins, yellow cake, baked custard, apple pie, tuna casserole, frozen tuna casserole, cheese soufflé, and meat loaf were baked in preheated and non-preheated standard gas, continuous-clean gas, standard electric, and self-cleaning electric ovens. Products generally required 5 min. or less extra baking time when cooked in non-preheated rather than in preheated ovens. The variability in baking times often was less between preheated and non-preheated ovens than among oven types. Calculated energy consumption values showed that usually less energy was required to bake products in non-preheated than in preheated ovens; savings averaged about 10 percent. Few significant differences were found in physical measurements or eating quality either between preheated and non-preheated ovens or among oven types. Overall, for the products tested, findings confirmed that preheating the oven is not essential for good product quality and, therefore, is an unnecessary use of energy. PMID:7108076

  1. 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...

  2. Preheat effects on microballoon laser fusion implosions

    International Nuclear Information System (INIS)

    Nonequilibrium hydroburn simulations of early laser-driven compression experiments indicate that low energy photons from the vicinity of the ablation surface are preheating the microballoon-pushers, thereby severely limiting the compressions achieved (similar degradation may result from 1 to 4 percent energy deposition by superthermal electrons). This implies an 8- to 27-fold increase in the energy requirements for breakeven, unless radiative preheat can be drastically reduced by, say, the use of composite ablator-pushers. (auth)

  3. Pre-heating mitigates composite degradation

    Science.gov (United States)

    da SILVA, Jessika Calixto; Rogério Vieira, REGES; REGE, Inara Carneiro Costa; CRUZ, Carlos Alberto dos Santos; VAZ, Luís Geraldo; ESTRELA, Carlos; de CASTRO, Fabrício Luscino Alves

    2015-01-01

    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. PMID:26814459

  4. Preheating after small-field inflation

    International Nuclear Information System (INIS)

    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 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 matter-dominated stage before the Universe thermalizes, depending on the energy scale of inflation and the details of the inflaton interactions. Finally, another feature of these models is that the spectrum of the inflaton fluctuations at the end of preheating may be peaked around the Hubble scale. In fact, because preheating starts when the second slow-roll parameter |η| becomes of order unity while the first slow-roll parameter ε is still much smaller than 1, the Universe is still inflating during preheating and the modes amplified by the initial tachyonic instability leave the Hubble radius. This may lead to an abundant production of primordial black holes and gravitational waves with frequencies today which are naturally small enough to fall into the range accessible by high-sensitivity interferometric experiments.

  5. 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.

  6. 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.

  7. Gravitational Radiation from Preheating with Many Fields

    CERN Document Server

    Giblin, John T; Siemens, Xavier

    2010-01-01

    Parametric resonances provide a mechanism by which particles can be created just after inflation. Thus far, attention has focused on a single or many inflaton fields coupled to a single scalar field. However, generically we expect the inflaton to couple to many other relativistic degrees of freedom present in the early universe. Using simulations in an expanding Friedmann-Lema\\^itre-Robertson-Walker spacetime, in this paper we show how preheating is affected by the addition of multiple fields coupled to the inflaton. We focus our attention on gravitational wave production--an important potential observational signature of the preheating stage. We find that preheating and its gravitational wave signature is robust to the coupling of the inflaton to more matter fields.

  8. Elevated temperature forming method and preheater apparatus

    Science.gov (United States)

    Krajewski, Paul E; Hammar, Richard Harry; Singh, Jugraj; Cedar, Dennis; Friedman, Peter A; Luo, Yingbing

    2013-06-11

    An elevated temperature forming system in which a sheet metal workpiece is provided in a first stage position of a multi-stage pre-heater, is heated to a first stage temperature lower than a desired pre-heat temperature, is moved to a final stage position where it is heated to a desired final stage temperature, is transferred to a forming press, and is formed by the forming press. The preheater includes upper and lower platens that transfer heat into workpieces disposed between the platens. A shim spaces the upper platen from the lower platen by a distance greater than a thickness of the workpieces to be heated by the platens and less than a distance at which the upper platen would require an undesirably high input of energy to effectively heat the workpiece without being pressed into contact with the workpiece.

  9. Galaxy Formation in Preheated Intergalactic Media

    CERN Document Server

    Mo, H J

    2002-01-01

    We outline a scenario of galaxy formation in which the gas in galaxy-forming regions was preheated to high entropy by vigorous energy feedback associated with the formation of stars in old ellipticals and bulges and with AGN activity. Such preheating likely occurred at redshifts z ~ 2-3, and can produce the entropy excess observed today in low-mass clusters of galaxies without destroying the bulk of the Lyman alpha forest. Subsequent galaxy formation is affected by the preheating, because the gas no longer follows the dark matter on galaxy scales. The hot gas around galaxy haloes has very shallow profiles and emits only weakly in the X-ray. Cooling in a preheated halo is not inside-out, because the cooling efficiency does not change significantly with radius. Only part of the gas in a protogalaxy region can cool and be accreted into the final galaxy halo. The accreted gas is likely in diffuse clouds and so does not lose angular momentum to the dark matter. Cluster ellipticals are produced by mergers of stella...

  10. Aspects of wave turbulence in preheating

    International Nuclear Information System (INIS)

    In this work we have studied the nonlinear preheating dynamics of several inflationary models. It is well established that after a linear stage of preheating characterized by the parametric resonance, the nonlinear dynamics becomes relevant driving the system towards turbulence. Wave turbulence is the appropriated description of this phase since the matter contents are fields instead of usual fluids. Turbulence develops due to the nonlinear interations of waves, here represented by the small inhomogeneities of the scalar fields. We present relevant aspects of wave turbulence such as the Kolmogorov-Zakharov spectrum in frequency and wave number that indicates the energy transfer through scales. From the power spectrum of the matter energy density we were able to estimate the temperature of the thermalized system

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

    Science.gov (United States)

    Ali, Mohamed Mahmoud; Kvande, Halvor

    2016-06-01

    ABSTRACT 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.

  12. Preheating and locked inflation: an analytic approach towards parametric resonance

    CERN Document Server

    Wang, Lingfei

    2011-01-01

    We take an analytic approach towards the framework of parametric resonance and apply it on preheating and locked inflation. A two-scalar toy model is analytically solved for the \\lambda\\phi^2\\chi^2 coupling for the homogenous modes. The effects of dynamic universe background and backreaction are taken into account. We show the average effect of parametric resonance to be that \\chi's amplitude doubles for each cycle of \\phi. Our framework partly solves the preheating scenario, showing two distinct stages of preheating and making the parameters of preheating analytically calculable. It is demonstrated for slowroll inflation models, preheating is terminated, if by backreaction, typically in the 5th e-fold. Under our framework, a possible inhomogeneity amplification effect is also found during preheating, which both may pose strong constraints on some inflationary models and may amplify tiny existing inhomogeneities to the desired scale. For demonstration, we show it rules out the backreaction end of preheating o...

  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. Study of Substrate Preheating on Flattening Behavior of Thermal-Sprayed Copper Particles

    Science.gov (United States)

    Yang, K.; Fukumoto, M.; Yasui, T.; Yamada, M.

    2010-12-01

    In this study, the effect of substrate preheating on flattening behavior of thermal-sprayed particles was systematically investigated. A part of mirror-polished AISI304 substrates were preheated to 573 and 773 K for 10 min, and then exposed to an air atmosphere for different durations of up to 48 h, respectively. Contact angle of water droplet was measured on the substrate under designated conditions. It was found that the contact angle increased gradually with the increase of substrate duration after preheating. Moreover, smaller contact angle was maintained on the substrate with higher preheating temperature. Commercially available Cu powders were thermally sprayed onto the substrates with the same thermal treatment history as contact angle measurement using atmospheric plasma-spray technique. The splat shape had a transitional changing tendency from a splash splat to a disk one on the substrate with a short duration after preheating, while reappearance of splash splat with the increase of duration was confirmed. In general, wetting of substrate surface by molten particles may dominate the flattening behavior of thermal-sprayed particles. The occurrence of desorption of adsorbed gas/condensation caused by substrate preheating likely provides good wetting. On the other hand, the poor wetting may be attributed to the re-adsorption of gas/condensation on the substrate surface with the increase of duration. In addition, the shear adhesion strength of coating fabricated on blasted AISI304 substrate was enhanced on the once-heated substrate, but weakened with the increase of duration. The changing tendency of the coating adhesion strength and the wetting of substrate by droplet corresponded quite well with each other.

  15. Modelling of the preheating process of filament tows

    International Nuclear Information System (INIS)

    Filament winding of powder impregnated fibres has been applied to produce composite rings. Important steps in the process are the preheating of the tow within an infrared (IR) preheater. The paper provides results of modelling the heating process of the tow within the preheater. The calculations are focused on the evaluation of the temperature not only at the surface of the tow but also across the whole diameter, i.e. the skin-core effect is investigated. (orig.)

  16. Reducing the Surface Degradation of Aluminum Extrusion Dies During Preheating

    Science.gov (United States)

    Stratton, Paul

    2010-07-01

    Aluminum extrusion dies are usually made from H13 steel that is ferritically nitrocarburized to minimize wear and pick-up. Before being placed in the extrusion press, the dies are preheated to minimize thermal shock at the start of the extrusion cycle. During the preheating time, the nitrocarburized layer oxidizes. Some of this layer can break away during extrusion leaving marks on the product. Although inerting the preheat furnaces with nitrogen has been found to reduce the oxidation, it does not solve the problem completely. Experiments have shown that a small addition of ammonia to the preheating protective atmosphere could eliminate oxidation and prevent nitrogen loss from the surface nitride layer.

  17. Tachyonic Resonance Preheating in Expanding Universe

    CERN Document Server

    Abolhasani, Ali Akbar; Sheikh-Jabbari, M M

    2009-01-01

    In this paper the tachyonic resonance preheating generated from the bosonic trilinear $\\phi\\chi^2$ interactions in an expanding Universe is studied. In $\\lambda\\phi^4/4$ inflationary model the trilinear interaction, in contrast to the four-legs $\\phi^2\\chi^2$, breaks the conformal symmetry explicitly and the resonant source term becomes non-periodic, making the Floquet theorem inapplicable. We find that the occupation number of the produced $\\chi$-particles has a non-linear exponential growth with exponent $\\sim x^{3/2}$, where $x$ is the conformal time. This should be contrasted with preheating from a periodic resonant source, arising for example from the four-legs $\\phi^2\\chi^2$ interaction, where the occupation number has a linear exponential growth. We present an analytic method to compute the interference term coming from phases accumulated in non-tachyonic scattering regions and show that the effects of the interference term causes ripples on $x^{3/2}$ curve, a result which is confirmed by numerical ana...

  18. PLIF - diagnostics of formaldehyde with kHz repetition rate in the mixing zone of liquid fuels and preheated air; PLIF - Diagnostik von Formaldehyd mit kHz-Repetitionsrate in der Mischzone von fluessigen Brennstoffen und vorgeheizter Luft

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, D.; Paa, W.; Triebel, W. [Institut fuer Physikalische Hochtechnologie e.V., Jena (Germany); Mengel, C.; Lucka, K.; Koehne, H. [Oel-Waerme-Institut gGmbH, Aachen (Germany)

    2005-07-01

    The mixing of liquid fuel and air is a key factor with respect to the quality and efficiency of combustion. A new concept uses a homogeneous fuel vapor/air-mixture generated in socalled cool flames. This process generates different products, e.g. formaldehyde. This can be measured by Planar Laser Induced Fluorescence (PLIF). A novel all solid state Yb-YAG disk laser system was used to determine the formaldehyde distribution an a technical reactor. This laser generates tunable, narrow bandwidth pulses at kHz repetition rate and energies of up to 25 mJ around 10300 nm. After frequency conversion into the UV spectral range the laser beam is shaped to a lightsheet. The detection of 2D-LIF is realized by an intensified CCD camera. The formaldehyde distribution of n-heptane and light fuel oil was detected at different heights in the reactor. The PLIF measurements at kHz repetition rate allow to determine formaldehyde distribution and to visualize the turbulent reaction zone and droplets of fuel, which was not yet fully vaporized. This mixing technique can be applied in the fields of fuel cells, in combustion technique for gas turbines and for heat supply. (orig.)

  19. 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.

  20. 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.

  1. 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.

  2. Experimental study on propane/oxygen and natural gas/oxygen laminar diffusion flames in diluting and preheating conditions

    Directory of Open Access Journals (Sweden)

    Kashir Babak

    2012-01-01

    Full Text Available In the present study, propane/oxygen and natural gas/oxygen diffusion flames within laminar regime have been investigated experimentally to determine the effects of oxidant preheating and diluting. This research has been divided into two parts. At first, effect of oxygen dilution with nitrogen and carbon dioxide gases has been investigated. In this section, stability and flame configuration variations are studied. Furthermore, it is inferred that combustion of natural gas and propane with pure oxygen can increase flame stability against increasing the fuel jet velocities through increasing burning velocity of the flame as compared with the combustion of natural gas or propane with normal air. In the other part, oxidant stream preheating up to 480 K and contemporaneous diluting with nitrogen or carbon dioxide are investigated and results are compared with non-preheating tests. Preheating causes more flame stability with respect to dilution process. Also, Due to combustion products temperature rise and also reduction in ignition delay time in preheating, these flames are more stable and also visually more luminous in comparison with normal temperature flames.

  3. Preheating and locked inflation: an analytic approach towards parametric resonance

    International Nuclear Information System (INIS)

    We take an analytic approach towards the framework of parametric resonance and apply it on preheating and locked inflation. A two-scalar toy model is analytically solved for the λφ2χ2 coupling for the homogenous modes. The effects of dynamic universe background and backreaction are taken into account. We show the average effect of parametric resonance to be that χ's amplitude doubles for each cycle of φ. Our framework partly solves the broad resonance for preheating scenario, showing two distinct stages of preheating and making the parameters of preheating analytically calculable. It is demonstrated for slowroll inflation models, preheating is terminated, if by backreaction, typically in the 5th e-fold. Under our framework, a possible inhomogeneity amplification effect is also found during preheating, which both may pose strong constraints on some inflationary models and may amplify tiny existing inhomogeneities to the desired scale. For demonstration, we show it rules out the backreaction end of preheating of the quadratic slowroll inflation model with mass m ∼ 10−6. For locked inflation, parametric resonance is found to be inhibited if φ has more than one real component

  4. The effect of preheat temperature and inter-pass reheating on microstructure and texture evolution during hot rolling of Ti-6Al-4V

    International Nuclear Information System (INIS)

    The effect of preheat temperature and inter-pass reheating on microstructure and texture evolution during unidirectional hot rolling of Ti-6Al-4V in the alpha + beta field was investigated. Three different heating schedules were used to roll plates at 10% reduction per pass to a 3:1 total reduction (true strain = 1.15): (1) preheat at 955 deg. C with inter-pass reheating for 3 min, (2) preheat at 955 deg. C without inter-pass reheating, and (3) preheat at 815 deg. C with inter-pass reheating for 3 min. Following rolling, each plate was air cooled to simulate production practice. The microstructures and textures were determined using electron-backscatter and X-ray diffraction techniques. The results revealed that the intensity of basal poles decreased along the rolling direction and increased along the normal and transverse directions with decreasing rolling (furnace) temperature or the elimination of reheating between passes

  5. 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...

  6. Gravity Waves from Tachyonic Preheating after Hybrid Inflation

    OpenAIRE

    Dufaux, Jean-Francois; Felder, Gary; 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 ...

  7. Preheating the Combustion Components and Furnace Operation Stimulation

    OpenAIRE

    Димитров, А. Д.; Шраменко, А. Н.; Пядухов, В. А.

    2015-01-01

    Different options of the internal use of the heat of effluent combustion products for the working heat process plants (HTHP) have been compared. Basic factors that affect the efficiency and the affordability of the HTHP operation were determined. The methods of the computation of the influence of the preliminary preheated material and preheated combustion products on the productivity and specific fuel consumption were given on the basis of balance equations. The influence produced on these va...

  8. Radiation preheating can trigger transition from deflagration to detonation

    OpenAIRE

    Karlin, Vladimir

    2010-01-01

    In this article effect of radiation preheating of unburnt mixture by propagating deflagration front is studied from the viewpoint of its ability to form a promoting temperature gradient and trigger transition to detonation. First, we investigate the effect of radiation preheating of the unburnt mixtures, when they are traveling through the wrinkles on the flame surface, in order to estimate a possibility of significant temperature rise. Subsequently, numerical simulations of a simplified math...

  9. Effect of inflation on parametric resonance during preheating

    International Nuclear Information System (INIS)

    The effect of inflation on parametric resonance during preheating is investigated. The behaviour of the preheating scalar field during inflation is investigated and is found to become squeezed in cases ranging from small-scale cases to large-scale cases. However, the positive-frequency solution is usually adopted in the initial condition of the scalar field at preheating. Although large squeezing occurs during inflation, the difference in the comoving occupation number of particles nk between two initial conditions is shown to be not so large. Rather, the ratio nk varies from 0.2 to 5.0, depending on k. In order to clarify this situation, we introduce the squeeze formulation. The squeeze parameters r and φ are calculated not only in preheating, but also in inflation. Since the squeeze parameters are calculated from inflation to preheating, we can clarify the behaviour of the parametric resonance. In preheating, the behaviour of r is shown to remain relatively unchanged with respect to k; however, the squeeze angle φ displays different behaviour for large-scale cases and small-scale cases

  10. Effect of inflation on parametric resonance during preheating

    CERN Document Server

    Hirai, S

    2002-01-01

    The effect of inflation on parametric resonance during preheating is investigated. The behaviour of the preheating scalar field during inflation is investigated and is found to become squeezed in cases ranging from small-scale cases to large-scale cases. However, the positive-frequency solution is usually adopted in the initial condition of the scalar field at preheating. Although large squeezing occurs during inflation, the difference in the comoving occupation number of particles n sub k between two initial conditions is shown to be not so large. Rather, the ratio n sub k varies from 0.2 to 5.0, depending on k. In order to clarify this situation, we introduce the squeeze formulation. The squeeze parameters r and phi are calculated not only in preheating, but also in inflation. Since the squeeze parameters are calculated from inflation to preheating, we can clarify the behaviour of the parametric resonance. In preheating, the behaviour of r is shown to remain relatively unchanged with respect to k; however, ...

  11. Gravitational waves from preheating in M-flation

    International Nuclear Information System (INIS)

    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 U(N) gauge group. One of these 3N2 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 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. 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 gravitational waves produced during the preheating stage following M-flation. The preliminary numerical simulation of the spectrum from multi-preheat fields peaks in the GHz band with an amplitude Ωgwh2∝10−16, suggesting that the model has concrete predictions for the ultra-high frequency gravity-wave probes. This signature could be used to distinguish the model from rival inflationary models

  12. 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.

  13. 46 CFR 56.85-10 - Preheating.

    Science.gov (United States)

    2010-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES... still air. When furnace cooling is used, the pipe sections must be cooled in the furnace to 1000 °F and... performed on a circumferential band of the pipe. The minimum width of this band, centered on the weld,...

  14. Energy, exergy, environmental and economic analysis of industrial fired heaters based on heat recovery and preheating techniques

    International Nuclear Information System (INIS)

    Highlights: • 4-E analysis of a typical industrial grade fired heater unit is studied. • This analysis is accomplished for the first time in this study. • Heat recovery and air preheating lead to substantial reduction in the fuel consumption. • The company’s current costs are tremendously reduced by these methods. • The methods lead to mitigation in GHG emission and to reduction in the associated taxes. - Abstract: Fired heaters are ubiquitous in both the petroleum and petrochemical industries, due to it being vital in their day to day operations. They form major components in petroleum refineries, petrochemical facilities, and processing units. This study was commissioned in order to analyze the economic benefits of incorporating both heat recovery and air preheating methods into the existing fired heater units. Four fired heater units were analyzed from the energy and environmental point of views. Moreover, the second law efficiency and the rate of irreversibility were also analyzed via the exergy analysis. Both analyses was indicative of the fact that the heat recovery process enhances both the first and second law efficiencies while simultaneously assisting in the production of high and low pressure water steam. The implementation and usage of the process improves the thermal and exergy efficiencies from 63.4% to 71.7% and 49.4%, to 54.8%, respectively. Additionally, the heat recovery and air preheating methods leads to a substantial reduction in fuel consumption, in the realm of up to 7.4%, while also simultaneously decreasing heat loss and the irreversibility of the unit. Nevertheless, the results of the economic analysis posits that although utilizing an air preheater unit enhances the thermal performance of the system, due to the air preheater’s capital and maintenance costs, incorporating an air preheater unit to an existing fired heater is not economically justifiable. Furthermore, the results of the sensitivity analysis and payback period

  15. Bioprotection by local and whole-body preheating. Bioprotection of damage to mice tongue from burning by local preheating of oral cavity and of radiation damage of small intestine from whole-body preheating

    International Nuclear Information System (INIS)

    We have reported the cytoprotective effects of heat shock protein (HSP) 70 on various stress damage induced by mild heating. In this study, we examined the cytoprotective effects of HSP 70 induced by the local preheating of the oral cavity of mice at 42 deg C for 30 mm, and the following results were obtained. We also examined the cytoprotective effects against radiation injury by whole-body preheating at 41.3-41.6 deg C for 30 min. The concentration of HSP 70 in lymphocytes was increased 2 days after preheating, but not significantly. The concentration of HSP 70 in masseter muscle was significantly increased 2 days after preheating. Under non-heat stress (control), tongue muscle was strongly stained with immunoblotting of HSP 72 antibody, an antibody of induced-type HSP 70. Tongue damage and weight loss of the mice in the preheating group, whose tongues were burned, were less than in the control group. These results showed that HSP 70 induced by local preheating of the oral cavity protected against tongue damage from burning. Radiation injury of the small intestine on HE stain of whole-body radiated mice was obviously reduced by whole-body preheating. Decrease of the ratio of the villus length to the crypt of whole body-irradiated mice was significantly improved by whole-body preheating. From these results, it was concluded that local and whole-body preheating were useful for cytoprotection from stressful damage. (author)

  16. A study of energy exchange in earth air tubes

    OpenAIRE

    Bexell, Jonas; Bjureus, Erik

    2010-01-01

    As energy issues today are of great interest the writers of this report have done a research about an alternative to save energy by reducing the cost of preheating the outdoor air. By taking the outdoor air to the ventilation system via a pipe buried in the ground, you can preheat the outdoor air, which, in turn, could save energy. By doing this you do not have to bring as much energy to preheat the supply air, to get the desired supply air temperature. The report also explains if the earth a...

  17. Changes in OSL properties of quartz by preheating: an interpretation

    International Nuclear Information System (INIS)

    A study of OSL variation with preheat temperature showed, in a majority of cases, that OSL recorded at room temperature, increases above 200 deg. C before the normal drainage at higher temperature. To explain this behaviour, an alternative interpretation to the common 'electronic thermal transfer' mechanism is suggested, supported by a study of hydrothermally grown quartz crystals. This interpretation involves impurities in substitution of Si4+, specially Al3+, which are associated with species like, in the case of quartz, hydrogen (H+, in fact, OH-) and alkali ions (Li+, Na+, K+). These monovalent ions usually act as charge compensators and are mobile during heating. As a consequence of the mobility and a possible irreversible exchange between compensators, the number of radiative recombination centres associated with the OSL trap(s), observable within the detection spectral window used (250-400 nm), increases during preheating. This phenomenon could lead to a wrong ED determination

  18. CFD modeling of fouling in crude oil pre-heaters

    International Nuclear Information System (INIS)

    Highlights: ► A conceptual CFD-based model to predict fouling in industrial crude oil pre-heaters. ► Tracing fouling formation in the induction and developing continuation periods. ► Effect of chemical components, shell-side HTC and turbulent flow on the fouling rate. - Abstract: In this study, a conceptual procedure based on the computational fluid dynamic (CFD) technique has been developed to predict fouling rate in an industrial crude oil pre-heater. According to the developed CFD concept crude oil was assumed to be composed of three pseudo-components comprising of petroleum, asphaltene and salt. The binary diffusion coefficients were appropriately categorized into five different groups. The species transport model was applied to simulate the mixing and transport of chemical species. The possibility of adherence of reaction products to the wall was taken into account by applying a high viscosity for the products in competition with the shear stress on the wall. Results showed a reasonable agreement between the model predictions and the plant data. The CFD model could be applied to new operating conditions to investigate the details of the crude oil fouling in the industrial pre-heaters.

  19. The effect of preheating on the IRSL signal from feldspar

    DEFF Research Database (Denmark)

    Murray, A.S.; Buylaert, J.P.; Thomsen, Kristina Jørkov;

    2009-01-01

    relationship between the loss of blue IRSL and TL signals with preheating, and the effect of prior IRSL on the TL signal. Using IRSL measured at 50 °C and a SAR protocol, we then examine the dependence on preheat temperature of equivalent dose (De), laboratory fading rate (g), and the resulting luminescence......It is difficult to relate the IRSL signal from feldspar to a particular region of the TL curve; prior IR stimulation reduces the TL signal over a wide range of temperatures. Such data are apparently consistent with the observation from pulse anneal experiments that a laboratory-induced IRSL signal...... evidence for an increase in age with preheat temperature. We therefore conclude that the main dosimetry trap(s) in feldspar are not significantly eroded by laboratory heating for up to 60 s at 320 °C, and we tentatively identify the source of this IRSL as a TL peak lying between 410 and 420 °C; this...

  20. 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.

  1. Bruce NGS A Unit 4 preheater divider plate failure

    International Nuclear Information System (INIS)

    On May 19, 1995, without any prior operational indications, Bruce A discovered preheater divider plate damage in Unit 4 that had the potential to have a major impact on the continued safe operation of the station. Further investigations indicated that Unit 4 may have been operating with this damage for as long as ten years. In the two months following the discovery, Bruce A has procured and replaced the 4 divider plates, located most of the missing pieces, retrieved pieces from the PHT system, investigated historical operational information, performed detailed analytical investigations, investigated root cause, performed in-situ and mock-up testing, updated operational procedures and installed DP monitoring equipment

  2. 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.

  3. Modulated perturbations from instant preheating after new ekpyrosis

    International Nuclear Information System (INIS)

    I present a mechanism to transfer the spectrum of perturbations in a scalar isocurvature field ξ onto the matter content in the radiation era via modulated, instant preheating after ekpyrosis. In this setup, ξ determines the coupling constant relevant for the decay of a preheat matter field into fermions. The resulting power spectrum is scale invariant if ξ remains close to a scaling solution in new ekpyrotic models of the Universe; by construction the spectrum is independent of the detailed physics near the bounce. The process differs from the curvaton mechanism, which has been used recently to revive the ekpyrotic scenario, in that no peculiar behavior of ξ shortly before or during the bounce is needed. In addition, a concrete and efficient realization of reheating after ekpyrosis is provided; this mechanism is not tied to ekpyrotic models, but could equally well be used in other setups, for instance inflationary ones. I estimate non-Gaussianities and find no additional contributions in the most simple realizations, in contrast to models using the curvaton mechanism.

  4. Low SO2 Emission Preheaters for Cement Production

    DEFF Research Database (Denmark)

    Rasmussen, Martin Hagsted

    sulphide, which occurs between 300 and 600 °C. Of the formed SO2, around 50% is often said to be emitted from the preheater. However, large variations in this number have been observed, with the circulation of CaO from the calciner given as the main reason for this phenomenon. One of the experimental goals...... second, which was possible using an entrained flow reactor. Furthermore, the experimental results were found to be limited by both external and internal diffusion. The reaction product was identified as a mixture of CaSO3 and CaSO4. For temperatures below 600 °C no effect from O2 was observed. At low CO2...... it was concluded that CaO recirculation within the preheater tower does not influence the SO2 emission to any significant extend. This conclusion is opposite to what previously has been stated. Modelling of experimental results concentrates on the results obtained for CaO in non-CO2-enriched atmospheres. Due...

  5. A new interferometer to measure preheat in laser targets

    International Nuclear Information System (INIS)

    Many interferometer designs exist to measure the distance change through a fringe displacement. Different interferometers were used to measure the movement of the backside of a heated foil in laser plasma interactions. However, when a laser heated target sits in the middle of a target chamber with noise from pumps and other sources of vibrations, the fringes become difficult to observe and align. We have built a differential interferometer where the light paths in each arm of the interferometer retrace each other, hence making the fringes much less sensitive to vibrations than a regular interferometer. This allows the main part of the interferometer to sit outside the vacuum chamber, where it is easy to align. The final focusing element resides close to the target and collects a significant amount of the scattered light. In this investigation we will use the interferometer to measure the expansion of the backside of a preheated target in the TRIDENT chamber. Using the coefficient of linear expansion, the heat capacity of the material, and the expansion distance, we estimate a time dependent preheat temperature of the target

  6. Combined Preheating on the lattice with applications to Higgs inflation

    CERN Document Server

    Repond, Joël

    2016-01-01

    We use classical lattice simulations in 3+1 dimensions to study the interplay between the resonant production of particles during preheating and the subsequent decay of these into a set of secondary species. We choose to work in a simplified version of Higgs inflation in which the Higgs field non-minimally coupled to gravity plays the role of the inflaton. Our numerical results extend the analytical estimates in the literature beyond the linear regime and shed some light on the limitations of the analytical techniques. The inclusion of fast and inefficient decays postpones the onset of parametric resonance by depleting the particles produced at the bottom of the potential. In spite of this delay, fermions are shown to play an important role on the destruction of the inflaton field. The limitations of our approach and its applications to a realistic Higgs inflation scenario are also discussed.

  7. Pre-heating in the framework of massive gravity

    Science.gov (United States)

    Maity, Debaprasad

    2016-09-01

    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.

  8. Higgs vacuum metastabilities in primordial inflation, preheating, and reheating

    CERN Document Server

    Kohri, Kazunori

    2016-01-01

    From the current measurements of the Higgs boson mass and the top Yukawa coupling, it is suggested that there are instabilities in the effective Higgs potential below the Planck scale. If the energy scale of inflation is as large as the GUT scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum and produce a lot of AdS domains. If a possible nonminimal Higgs-gravity coupling or a possible inflaton-Higgs coupling is relatively large, such couplings can generate large effective mass terms, which can raise the effective Higgs potential and suppress the vacuum fluctuation of the Higgs field. After the primordial inflation however, such effective masses become ineffective against the Higgs potential and the couplings can generate further large fluctuations of the Higgs field via the parametric resonance and produce AdS domains in the preheating stage. Furthermore, thermal fluctuations of the Higgs field cannot be negligible in the proceeding reheating epo...

  9. Reheating the D-brane universe via instant preheating

    International Nuclear Information System (INIS)

    We investigate a possibility of reheating in a scenario of D-brane inflation in a warped deformed conifold background which includes perturbative corrections to throat geometry sourced by a chiral operator of dimension 3/2 in the conformal field theory. The effective D-brane potential, in this case, belongs to the class of nonoscillatory models of inflation for which the conventional reheating mechanism does not work. We find that gravitational particle production is inefficient and leads to reheating temperature of the order of 108 GeV. We show that instant preheating is quite suitable to the present scenario and can easily reheat the universe to a temperature which is higher by about 3 orders of magnitude than its counterpart associated with gravitational particle production. The reheating temperature is shown to be insensitive to a particular choice of inflationary parameters suitable to observations.

  10. 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.

  11. Thickness and Fuel Preheating Effects on Material Flammability in Microgravity from the BASS Experiment

    Science.gov (United States)

    Ferkul, Paul V.; Olson, Sandra L.; Takahashi, Fumiaki; Endo, Makoto; Johnson, Michael C.; T'ien, James S.

    2013-01-01

    The Burning and Suppression of Solids (BASS) experiment was performed on the International Space Station. Microgravity combustion tests burning thin and thick flat samples, acrylic spheres, and candles were conducted. The samples were mounted inside a small wind tunnel which could impose air flow speeds up to 40 cms. The wind tunnel was installed in the Microgravity Science Glovebox which supplied power, imaging, and a level of containment. The effects of air flow speed, fuel thickness, fuel preheating, and nitrogen dilution on flame appearance, flame growth, and spread rates were determined in both the opposed and concurrent flow configuration. In some cases, a jet of nitrogen was introduced to attempt to extinguish the flame. Microgravity flames were found to be especially sensitive to air flow speed in the range 0 to 5 cms. The gas phase response is much faster compared to the solid and so as the flow speed is changed, the flame responds with almost no delay. At the lowest speeds examined (less than 1 cms) all the flames tended to become dim blue and very stable. However, heat loss at these very low convective rates is small so the flames can burn for a long time. At moderate flow speeds (between about 1 and 5 cms) the flame continually heats the solid fuel resulting in an increasing fuel temperature, higher rate of fuel vaporization, and a stronger, more luminous flame as time progresses. Only the smallest flames burning acrylic slabs appeared to be adversely influenced by solid conductive heat loss, but even these burned for over 5 minutes before self-extinguishing. This has implications for spacecraft fire safety since a tiny flame might be undetected for a long time. While the small flame is not particularly hazardous if it remains small, the danger is that it might flare up if the air convection is suddenly increased or if the flame spreads into another fuel source.

  12. Dynamic interactions between the ground heat exchanger and environments in earth–air tunnel ventilation of buildings

    OpenAIRE

    Gan, Guohui

    2014-01-01

    Earth–air tunnel ventilation is an energy efficient method of preheating or cooling of supply air to abuilding. The purposes of this study are to investigate the performance of earth–air heat exchangersunder varying soil and atmosphere conditions and the interactions between the heat exchanger andenvironments. A computer program has been developed for simulation of the thermal performance of anearth–air heat exchanger for preheating and cooling of supply air, taking account of dynamic variati...

  13. Palaeodose underestimates caused by extended-duration preheats in the optical dating of quartz

    International Nuclear Information System (INIS)

    An optical dating study of some quartzose sediments from northern and southern Australia, north Africa and north-western Europe has revealed that palaeodose (P) underestimates of 10-40% are obtained when an extended-duration preheat of 160oC for 16 h is used. For these samples in the 0-60 ka age range, a preheat of 220oC for 5 min produces the correct P, as inferred from the concordance with thermoluminescence (TL) palaeodose determinations on the same sedimentary sample or on burnt flint. Independent support for use of the 220oC preheat is given by the agreement between optical ages younger than 30 ka and 14C age determinations on associated charcoal. The deleterious effect of the 160oC preheat is illustrated by growth curves of optically stimulated luminescence (OSL) vs added dose. These curves show that the 160oC preheat induces a dose-dependent increase in sample sensitivity, which may be related to activation of the pre-dose mechanism. The 160oC preheat also causes low-dose supralinearity, although the supralinearity correction is insufficient to reduce significantly the degree of P underestimation. A normalization method based on preheat-induced sensitivity changes of the 110oC TL peak, albeit limited by saturation effects, warrants further investigation. (author)

  14. Measurement of preheat in aluminium target in indirect drive using the SGIII prototype facilities

    Science.gov (United States)

    Zhang, C.; Wang, Z. B.; Liu, H.; Peng, X. S.; Wang, F.; Ding, Y. K.; Zheng, J.

    2016-03-01

    The velocity interferometer system for any reflector (VISAR) is used to demonstrate preheat effect in aluminium in indirect drive. The rear surface motion prior to shock front was observed and compared with a multi-group calculation. By properly adjusting the hard x-ray portion of the radiation source, the calculated rear surface motion fits well with the experimental results, which gives us confidence to predict the preheated temperature of the sample by hard x-rays. Further, the effect of hohlraum geometry is compared and discussed experimentally. The result suggests gas-filled hohlraum or hohlraum with low Z substrates should be considered to further reduce preheating.

  15. 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.

  16. 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.

    2015-12-01

    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.

  17. A Cold Front in a Preheated Galaxy Cluster

    CERN Document Server

    Bialek, J J; Evrard, A E; Bialek, John J.; Mohr, August E. Evrard & Joseph J.

    2002-01-01

    We present a simulated cluster of galaxies, modeled with a pre-heated intracluster medium, that exhibits X-ray features similar to the `cold fronts' seen in Chandra observations. Mock observations at a particular epoch show factor two discontinuities in X-ray temperature and factor four in surface brightness on a spatial scale <= 100 kpc. Analysis of the cluster's dynamical history reveals that the front is a transient contact discontinuity created by an ongoing merger of two roughly equal mass subgroups. The cold front feature in this realization is amplified by the adiabatic expansion of one of the subgroups following its ablation from the center of its local dark matter potential. The presence of cold front features in a cluster modeled without radiative cooling or magnetic fields implies that such relatively complex physics is not a necessary element of the phenomenon and suggests that the prevalence of such features in high resolution X-ray images of clusters may simply reflect the high frequency of o...

  18. Air

    Science.gov (United States)

    ... house) Industrial emissions (like smoke and chemicals from factories) Household cleaners (spray cleaners, air fresheners) Car emissions (like carbon monoxide) *All of these things make up “particle pollution.” They mostly come from cars, trucks, buses, and ...

  19. Effect of mold preheating on the microstructure of the investment cast ASTM F-75 implant alloy

    International Nuclear Information System (INIS)

    The ASTM F-75 (Co-28%Cr-6%Mo) is widely used as a biocompatible alloy in medicine for manufacturing implants. In this study, effect of mold preheating on the as-cast microstructure of the alloy was investigated using the solid investment casting process. Several mold preheating temperatures of 550, 700, 850 and 1000 degreeC were selected at the same melt superheat. The samples were characterized by optical microscopy, electron microscopy and macro-hardness test. The results showed that the size of grains and secondary carbides of the matrix was increased by increasing the mold preheating temperature. In addition, morphology of the M23C6 carbides was changed from the eutectic carbides precipitated in grain boundaries to the blocky shape precipitated in both carbide interface and dendritic matrix. The appropriate microstructure with nearly fine grains with homogeneous distribution of secondary phases was obtained at mold preheating temperature of about 850 degreeC.

  20. 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.

  1. Effect of Substrate Preheating, Roughness and Particles Size on Splat Morphology of Thermal Sprayed Coatings

    OpenAIRE

    MOHAMED, Djeghdjough; EDDINE, Bacha Nacer; NACER, Dilmi

    2015-01-01

    In thermal spraying process, a commercial powder is heated and accelerated simultaneously using a heat source and deposited in a molten or semi-molten condition on a prepared substrate. Coating quality highly depends on some important surface parameters such as the thermo-chemical and physical properties of both powder and substrate, the surface state, the preheated temperature, and the existence of oxidation. In pratice, it is commonly accepted that pre-heating the substrate, prior a  therma...

  2. On the generation of the non-gaussian curvature perturbation during preheating in inflationary universe

    CERN Document Server

    Kohri, Kazunori; Valenzuela-Toledo, Cesar A

    2009-01-01

    We see how the perturbation of a light field might affect preheating and hence generate a contribution to the spectrum and non-gaussianity of the curvature perturbation. We give general expressions based on the \\delta N formula, and apply them to the cases of quadratic and quartic chaotic inflation. In particular, we show "modulated preheating" in quadratic chaotic inflation can produce sizable amount of non-gaussianity, |f_{\\rm NL}| \\sim O(1) - O(10).

  3. 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.

  4. Air

    International Nuclear Information System (INIS)

    In recent years several regulations and standards for air quality and limits for air pollution were issued or are in preparation by the European Union, which have severe influence on the environmental monitoring and legislation in Austria. This chapter of the environmental control report of Austria gives an overview about the legal situation of air pollution control in the European Union and in specific the legal situation in Austria. It gives a comprehensive inventory of air pollution measurements for the whole area of Austria of total suspended particulates, ozone, volatile organic compounds, nitrogen oxides, sulfur dioxide, carbon monoxide, heavy metals, benzene, dioxin, polycyclic aromatic hydrocarbons and eutrophication. For each of these pollutants the measured emission values throughout Austria are given in tables and geographical charts, the environmental impact is discussed, statistical data and time series of the emission sources are given and legal regulations and measures for an effective environmental pollution control are discussed. In particular the impact of fossil-fuel power plants on the air pollution is analyzed. (a.n.)

  5. Enhancement of machinability by workpiece preheating in end milling of Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    M.I. Hossain

    2008-12-01

    Full Text Available Purpose: The main objective of this paper is to investigate the effect of workpiece preheating with high frequency induction heating on improvement of machinability of Ti-6Al-4V during end milling using PVD TiAlN coated inserts. Tool life, cutting force and vibration were investigated during the experiments.Design/methodology/approach: End milling tests were conducted on Vertical Machining Centre (VMC ZPS, Model: MCFV 1060 with quarter immersion cutting. Titanium based alloy Ti-6Al-4V bar was used as the work-piece. Machining was performed with a 20 mm diameter end-mill tool holder (R390-020B20-11M fitted with one insert. PVD TiAlN coated carbide inserts (R390-11 T3 08E-ML 2030 were used in the experiments. All of the experiments were run at room temperature and preheated conditions. The preheated temperature was maintained at 420ºC and no phase change of the workpiece in preheating was ensured from the phase diagram of Ti-6Al-4V. High frequency induction heating was utilized to run the preheated machining.Findings: Preheating helps in substantially increasing tool life and in lowering down the cutting force value, lowering the amplitude of vibration and dynamic forces.Practical implications: The cost of machining Ti-6Al-4V is extremely high because of the relatively low machining speed and short tool life. Therefore, improving the machinability of Ti-6Al-4V is a research topic of much interest, with a number of approaches reported with varied results, such as, cryogenic cutting, high-pressure coolant, rotary-tool, and minimum quantity lubrication (MQL.Originality/value: A new approach of induction preheating to overcome the difficulties in machining of Ti-6Al-4V is presented in this paper. In preheated machining, high frequency induction heating is used as an external heat source to soften the work material surface layer in order to decrease its tensile strength and strain hardening. An experimental study has been performed to assess the

  6. 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...

  7. 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.

  8. 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.

  9. 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.

  10. Analysis preheat effect on thermal cycle and residual stress in a welded connection by FE simulation

    International Nuclear Information System (INIS)

    Preheat effect on thermal cycle and residual stress was studied by employing a 3D finite-element method. A circumferential multi-pass butt weld of pipes based on ASME section IX was investigated and the experiment for thermal cycle validation was carried out. A spherical heat source density with a Gaussian distribution was employed and by an appropriate coordinate system, the rotation of electrode around the pipe was modeled reasonably. Sequentially coupled, thermal–mechanical analysis was applied using temperature-dependent thermo-mechanical behavior for material properties and the variation in peak temperature, cooling rate, and the axial residual stress due to the preheat effect were evaluated. The simulation results revealed that the pattern of final residual stress was influenced by the preheat temperature. However the thermal cycle experienced in the welding zone seems to be significantly affected by the preheat temperature. -- Highlights: • FEA reveals temperature peaks follow reasonably the sequence of weld. • At the inner surface of the welded pipe, tensile axial residual stress is serious. • Preheat has major effect on thermal cycle, but on residual stress is not apparent. • Change in essential WPS parameters can be investigated by FE simulation precisely

  11. A line-imaging velocity interferometer technique for shock diagnostics without x-ray preheat limitation.

    Science.gov (United States)

    Wang, Feng; Peng, Xiaoshi; Liu, Shenye; Xu, Tao; Mei, Lusheng; Jiang, Xiaohua; Ding, Yongkun

    2011-10-01

    A study was conducted with a line-imaging velocity interferometer on sandwich targets at the Shen Guang-III prototype laser facility in China, with the goal of eliminating the preheat effect. A sandwich target structure was used to reduce the x-ray preheat limitation (radiation temperature ~170 eV) in a radiative drive shock experiment. With a thick ablator, the preheat effect appeared before the shock arrived at the window. After adding a shield layer of high-Z material on the ablator, x-rays which penetrated the ablator were so weak that the blank-out effect could not be measured. This experiment indicates that the sandwich target may provide a valuable technique in experiments such as equation of state and shock timing for inertial confinement fusion studies. PMID:22047281

  12. Constraints on generating the primordial curvature perturbation and non-Gaussianity from instant preheating

    International Nuclear Information System (INIS)

    We analyse models of inflation in which isocurvature perturbations present during inflation are converted into the primordial curvature perturbation during instant preheating. This can be due to an asymmetry between the fields present either during inflation or during preheating. We consider all the constraints that the model must satisfy in order to be theoretically valid and to satisfy observations. We show that the constraints are very tight in all of the models proposed and special initial conditions are required for the models to work. In the case where the symmetry is strongly broken during inflation the non-Gaussianity parameter fNL is generally large and negative

  13. Solar pre-heating of water for steam generation in the friendship textile mill

    International Nuclear Information System (INIS)

    The technology of solar water heating is simple and can be used for pre-heating of water entering a boiler. In this paper the economics of solar pre-heating of water was calculated. The calculations were based on the performance and cost of a locally-made flat plate collector, and the performance and fuel consumption of a boiler in a textile mill. The results showed that a collector area of about 800 meter square with initial cost of about LS 5,000,000, could save annually about 130 tons of furnace oil. ( Author )

  14. The importance of the transmission flux in evaluating the preheat effect in x-ray driven ablation

    International Nuclear Information System (INIS)

    In x-ray driven ablation, the preheat effect is caused by the high energy x-rays that pass through the ablator. Thus, the transmission flux can be used to characterize preheat effect in a certain degree. With the radiation temperature being 200 eV, the transmission flux and preheat temperature of pure polymer (CH) have been studied by using the one-dimensional multi-group radiation hydrodynamic code MULTI-1D. By studying the spectrum of the transmitted x-rays, it is found that the energy of the transmitted x-rays is in the range of 2–5 keV for pure CH ablator. This is of importance for selecting a dopant for CH ablator. We also calculated both the preheat temperature of CH near the surface of thick target (47.66 μm) and the transmission flux of a thinner target (38.66 μm). It is found that the more transmission flux leads to the higher preheat temperature. Preheat effect of graded Si-doped CH targets with different doped concentrations has also been studied. The results are consistent with this phenomenon. By analyzing the relationship between the transmission flux and the preheat temperature, we have presented a novel method to evaluate preheat effect in x-ray driven ablation

  15. The Effect of Air Preheating in a Biomass CFB Gasifier using ASPEN Plus Simulation

    OpenAIRE

    Doherty, Wayne; Reynolds, Anthony; Kennedy, David

    2009-01-01

    In the context of climate change, increasing efficiency and energy security, biomass gasification is likely to play an important role in energy production. Atmospheric circulating fluidised bed (CFB) technology was selected for the current study. The primary objective of this research is to develop a computer simulation model of a CFB biomass gasifier that can accurately predict gasifier performance under various operating conditions. An original model was developed using ASPEN Plus (Advan...

  16. Heat pipe air preheater for gas-/oil-fired power plants

    International Nuclear Information System (INIS)

    With the rising costs of fuel, utilities are constantly looking for ways to improve the net plant heat rate of new and existing units. Significant heat rate improvements can be obtained by reducing the exit stack flue gas temperature. This project evaluated two technologies to reduce flue gas temperatures: heat pipes and liquid-coupled heat exchangers. The specific unit chosen for evaluating these systems was Pacific Gas ampersand Electric's 750 MW Moss Landing Power Plant, Unit 7. Both natural gas and low sulfur (0.5%) fuel oil are fired at this plant. Accordingly, the heat exchangers were required to operate on both fuels. This study investigated the heat recovery installation through the preliminary engineering level of detail. At the conclusion of this effort, the results indicated that neither concept was economically attractive for the retrofit situation involved. In addition, several major technical questions remained unresolved concerning the design of a single heat-exchange device capable of operating on gas (sulfur-free) and oil (sulfur-containing) environments over the full normal operating load range. While the technologies this study reviewed have been installed in actual power plant applications, the site-specific aspects of Moss Landing Unit 7 significantly influenced the estimated costs and performance of each alternative. Using more cost-effective and corrosion-resistant materials may help reduce costs. The following conditions would further enhance the viability of lowering exit gas temperatures: Higher capacity factors; rising fuel costs; greater use of sulfur-free fuels, such as natural gas; lower manufacturing costs for heat exchanger technologies; or new unit application

  17. Preheated milk proteins improve the stability of grape skin anthocyanins extracts.

    Science.gov (United States)

    He, Zhiyong; Xu, Mingzhu; Zeng, Maomao; Qin, Fang; Chen, Jie

    2016-11-01

    The effects of casein and whey proteins, preheated at 40-100°C and 45-60°C for 15min, respectively, on color loss and anthocyanins degradation in grape skin anthocyanins extracts (GSAE) at pH 3.2 and 6.3 were evaluated. Preheating milk proteins effectively improved their protective effects against color loss and anthocyanins degradation in GSAE solutions during thermal treatment (at 80°C for 2h), H2O2 oxidation (0.005% H2O2 for 1h) and illumination (at 5000lx for 5 d). Whey proteins and casein, preheated at 50°C and 60°C for 15min, respectively, demonstrated the optimal protective effects. However, preheated whey proteins had a better protective effect on the thermal, oxidation and photo stability of GSAE, decreasing the thermal, oxidative and photo degradation of anthocyanins in GSAE 71.59%, 32.22% and 56.92% at pH 3.2 and 54.91%, 22.89% and 46.68% at pH 6.3, respectively. PMID:27211641

  18. COMPARING STUDY OF BLENDING PREHEATING MODIFIED COAL COKING AND STAMPING COKING FOR DONGSHEN COAL

    Institute of Scientific and Technical Information of China (English)

    伍林; 尹学琼; 魏贤勇; 宗志敏; 陈清如

    1999-01-01

    The compaison of the properties of coke of three coking methods is introduced. The mechanical properties and high temperature reactivity of coke blending preheating modified Dongshen coal are improved obviously than those of normal coke, and achieve or exceed that of stamping coke. This method shews more ability of expending coking coal resources.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

  3. Feasibility and economic analysis of solid desiccant wheel used for dehumidification and preheating in blast furnace: A case study of steel plant, Nanjing, China

    International Nuclear Information System (INIS)

    To overcome the shortcomings of huge energy consumption from conventional dehumidification using lithium bromide adsorption refrigerating (LBARD) system, a novel desiccant wheel dehumidification and preheating (DWDP) system using two-stage desiccant wheel for blast furnace is brought forward. The DWDP system was designed for dehumidification and preheating in blast furnace of steel plant. It takes waste heat in the slag flushing water as desiccant regeneration and preheating energy. To validate the feasibility of the new DWDP system, experimental studies were conducted based on a steel plant in Nanjing, China. The experiment was designed to use DWDP system in humid outdoor climates e.g. summer seasons. The experimental results indicate that the moisture removal capacity of DWDP system can reach 8.7 g/kg which will lead to the improvement of steel production by 0.9% and the coal is saved of about 2100 tons per year. With the DWDP system, the energy consumed by cooling tower of slag flushing water can decrease 7.3%. All of these energy saved equates to 10.3 million CNY annually. A comparison of initial investment and operating cost between DWDP system and LBRAD system was then carried out. The results show that the initial investment and operating cost of DWDP system is 37% and 57% of present LBARD system, and the payback period is shortened 66%. - Highlights: • A novel two-stage desiccant wheel dehumidification system for blast furnace is proposed. • Average moisture removal of 8.7 g/kg is achieved and dehumidification efficiency is 47%. • Outlet humidity ratio is less than 10 g/kg that satisfies the requirement of blast air. • Waste heat in slag flushing water is utilized and 61.4 million kJ is saved annually. • The investment and operating cost is 37% and 57% of former dehumidification system

  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. Batch Preheat for glass and related furnace processing operations

    Energy Technology Data Exchange (ETDEWEB)

    Energy & Environmental Resources, Inc

    2002-08-12

    The objectives that our development work addressed are: (1) Establish through lab tests a salt eutectic with a melting point of about 250 F and a working range of 250 to 1800 F. (2) Establish the most economical material of construction for the screened salt eutectics identified in the first objective. (3) Establish the material of construction for the salt heater liner. Objectives 2 and 3 were determined through corrosion tests using selected metallurgical samples. Successful completion of the above-stated goals will be incorporated in a heat recovery design that can be used in high temperature processes and furnaces, typical of which is the glass melting process. The process design incorporates the following unit operations: a vertical batch heater (whereby the batch flows down through tubes in a shell and tube exchanger; a molten salt eutectic is circulated on the shell side); a molten salt heater utilizing furnace flue gas in a radiation type heater (molten salt is circulated in the annular space between the inner and outer shells of the vertical heater, and flue gas passes from the furnace exhaust through the inner shell of the heater); a cantilever type molten salt circulating pump; and a jacketed mixer/conveyor to drive off moisture from the batch prior to feeding the batch to the vertical batch heater. Historically, radiation heaters, when applied to glass or fiberglass furnace recuperation, have experienced failures due to uneven heat flux rates, which increases internal stresses and spot overheating conditions. Low heat transfer coefficients result in requirements for large heat transfer surface areas in gas to gas or gas to air exchangers. Fouling is another factor that results in lower unit availability and reduced performance. These factors are accommodated in this process by the incorporation of several design features. The salt heater will be a vertical double wall radiation design, similar to radiation air heaters used in high temperature heat

  6. Numerical investigation of nonlinear ablative single-mode Rayleigh–Taylor instability in the presence of preheating

    International Nuclear Information System (INIS)

    Nonlinear ablative single-mode Rayleigh–Taylor instability (RTI) with weak and strong preheatings has been investigated numerically. The numerical results for the linear growth rates obtained are in general agreement with a self-consistent linear stability analysis (Goncharov et al 1996 Phys. Plasmas 3 4665). The effects of preheating on the ablative RTI (ARTI) are shown to reduce its linear growth rate and mitigate the weakly nonlinear growth. It was found that the nonlinear evolution of the ARTI is strongly dependent on the preheating intensity and perturbation wavelength. There are three typical wavelength perturbations for the nonlinear evolution of the ARTI. In the ARTI with weak preheating, for a short-wavelength perturbation the spike can be ruptured in the highly nonlinear regime and for a middle/long-wavelength perturbation the Kelvin–Helmholtz mushroom-shaped patterns appear at the spike heads. In the ARTI with strong preheating for a middle-wavelength perturbation, jet-like spikes can be formed though the spikes can still be ruptured in its classical RTI (without thermal conductivity) counterpart. In summary, our numerical studies indicate that the preheating can have a pronounced influence on the nonlinear evolutions of the ARTI. Thus, it should be included in applications where preheating plays a vital role, such as inertial confinement fusion implosions and supernova explosions. (paper)

  7. Corrosion resistance improvement in Gas Tungsten Arc Welded 316L stainless steel joints through controlled preheat treatment

    International Nuclear Information System (INIS)

    Highlights: → Though the preheat treatment reduced the cooling rate, no sensitization occurred. → The delta ferrite content of welds reduced due to cooling retardment in welds. → Reduction in δ/γ boundaries was accompanied by decrement of passivation current. → Preheat treatment improved pitting resistance characteristics. → Increment of preheat temperature increased breakdown and repassivation potential. -- Abstract: In the present study, an attempt has been made to improve the corrosion characteristics of 316L stainless steel weldments through preheating at 450 oC and 650 oC. The infrared and Tungsten-Rhenium thermocouples were utilized to probe the cooling trend of heat affected zone (HAZ) and weld pool, respectively. X-ray diffraction (XRD) patterns, optical microscopy, electron microscopy, Energy Dispersion Spectroscopy (EDS) and ferritscope were also used to investigate the effect of preheating on microstructural characteristics within the weld and HAZ. Moreover, cyclic potentiodynamic test was carried out to evaluate the corrosion features of welds such as corrosion current, passivation current (IPP), breakdown potential (EB) and repassivation potential (Ere). Results revealed that preheating reduces the cooling rate of weld pool, accompanied by reduction of delta ferrite content of weldments. Moreover, it was observed that increment of preheat temperature improves corrosion behavior of weldments, including a lower passivation current and a more pitting resistance. These outcomes were mainly ascribed to decrease of austenite/delta ferrite interfaces as vulnerable sites to corrosion attacks, through preheat treatment. Observations showed no evidence of sensitization in preheated samples, which guaranteed the feasibility of suggested heat treatment.

  8. Reproducibility of LiF:Mg, Cup thermoluminescent dosimeter on kilo voltage and megavoltage photon beam using different preheat rate:A glow curve study

    International Nuclear Information System (INIS)

    Full-text: Post-irradiation annealing or preheat of the LiF based TLD prior readout is commonly practiced for routine dosimetry to eliminate low temperature glow peaks. The aim of this study is to determine the effect of different preheating rate technique prior readout on the reproducibility and glow curve structure of LiF:Mg, Cu, P or TLD-1OOH exposed to low (109kVp) energy and high energy (6MV) photon beam. TLD chips were read after 24 hours of irradiation with three different preheat techniques; no preheat, low preheat rate (100 degree Celsius/ 10 minutes) and high preheat rate (135 degree Celsius/ 10 seconds) and reproducibility of TL signals were assessed in term of Standard Deviation (SD) and glow curve peaks. The high preheat rate technique was the most reproducible method for low energy photon with 1.05 % of mean reproducibility followed by low preheat rate (1.16 %) and no-preheat (1.33 %) techniques. The high preheat rate techniques was also the most reproducible method for high energy photon with 0.767 % of mean reproducibility as compared to low preheat rate (1.281 %). However the high preheat technique record highest TL signal lost with 10.35 % and 6.04 % for 24 and 72 hours of delayed TLD readout with respectively compared to 9.27 % and 4.51 % for 24 and 72 hours by low preheat rate. The low preheat was found to be optimal to eliminate low peaks (peak 1 and 2) but enable to remove peak 3 as it was shifted up word to combine with the main peak 4 of TL glow peak. It can be concluded that the reproducibility and structure of glow curve was strongly influenced by preheat technique prior readout. (author)

  9. On the OSL curve shape and preheat treatment of electronic components from portable electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Woda, Clemens, E-mail: clemens.woda@helmholtz-muenchen.d [Helmholtz Zentrum Muenchen - German Research Centre for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Greilich, Steffen [Riso National Laboratory, Radiation Research Department, Roskilde (Denmark); Beerten, Koen [SCK-CEN, Radiation Protection Dosimetry and Calibration, Mol (Belgium)

    2010-03-15

    The shape of the OSL decay curve and the effect of longer time delays between accidental exposure and readout of alumina-rich electronic components from portable electronic devices are investigated. The OSL decay curve follows a hyperbolic decay function, which is interpreted as an approximation of several closely spaced or even a continuous distribution of single trap OSL decay functions. Longer time delays between exposure and readout lead to a rising dose vs. OSL integration time plot, when applying a low preheat. Supplementary TL investigations indicate a distribution in activation energies for the main dosimetric (190 {sup o}C) peak and that the lower temperature part could fade with a higher rate than the higher temperature part. Consequences for the applied preheat treatment prior to dose measurement are discussed.

  10. 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.

  11. Preheating after Multifield Inflation with Nonminimal Couplings, I: Covariant Formalism and Attractor Behavior

    CERN Document Server

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

    2015-01-01

    We study the preheating phase for multifield models of inflation involving nonminimal couplings. The strong single-field attractor behavior during inflation in these models generically persists after the end of inflation, thereby avoiding the "de-phasing" that is typical in multifield models with minimally coupled scalar fields. Hence we find efficient transfer of energy from the oscillating inflation field(s) to coupled fluctuations. We develop a doubly-covariant formalism for studying such resonances and identify several features of preheating specific to the nonminimal couplings, including effects that arise from the nontrivial field-space manifold. In particular, whereas long-wavelength fluctuations in both the adiabatic and isocurvature directions may be resonantly amplified for small or modest values of the dimensionless couplings, $\\xi_I \\leq 1$, we find suppression of the growth of long-wavelength isocurvature modes in the limit of strong coupling, $\\xi_I \\gg 1$.

  12. VISAR blanking due to preheating in a 2-pulses planar experiment at LULI facility

    Science.gov (United States)

    Videau, Laurent; Laffite, Stephane; Baton, Sophie; Combis, Patrick; Clerouin, Jean; Koenig, Michel; Recoules, Vanina; Rousseaux, Christophe

    2014-10-01

    Optical diagnostics, such as VISAR (Velocity Interferometer System for Any Reflector), have become essential in shock timing experiments. Their high precisions allow an accurate measurement of shock velocities and chronometry. But, measurements can be compromised by x-ray preheating. In planar shock coalescence experiments recently performed at the LULI facility, VISAR signal loss was observed. In these experiments, a strong shock, launched by a high-intensity spike, catches up with a first one, initially launched by a low-intensity beam. VISAR signal disparition is due to x-ray generated by spike absorption in corona. It does not occur if high-intensity spike starts after VISAR probe beam begins to reflect off the first shock. Based on optical index assessment in quartz, VISAR diagnostic is modelized and compares favorably to experimental results. This provides evidence of the impact of x-ray preheating on VISAR absorption in quartz.

  13. The use of distributed micro processors for sodium pre-heating system

    International Nuclear Information System (INIS)

    This article deals with a hierarchy/distributed control system for the sodium system in a Liquid Cooled Fast Breeder Reactor (LMFBR). The control system consists of mini-computers, a computerized control panel, and distributed front-end units with micro-computer. In this system, the concentration of the plant operation information and the distribution of the control function are aimed at improving man-machine communication to increase system availability. The preheating control device with a micro-computer dealing with several thousands of temperature control points and the preheating system to maintain piping and components above the sodium melting temperature has been developed and tested at actual sodium test facilities, and the result satisfies system requirements of the prototype LMFBR. (auth)

  14. Hall cell energy recovery and anode pre-heating, gauging the opportunity

    Science.gov (United States)

    Fortini, Otavio

    2011-08-01

    Anode pre-heating was proposed as an alternative for recycling waste heat from smelting operations, which currently consume substantially more energy than the theoretical minimum required. Aside from direct electricity savings, anode pre-heating can provide extra metal production and reduce carbon dioxide emissions. Public data on energy and aluminum production is analyzed to examine the value of these three potential components and define a research development path. It is concluded that indirect process gains show the most potential value with economies on the order of 3 TWh per year in electricity, an avoidance of about 1.8 million metric tons of CO2 emissions, and an increase in production capacity of about 200,000 metric tons of aluminum per year without any expansion of installed capacity.

  15. The charged inflaton and its gauge fields: preheating and initial conditions for reheating

    CERN Document Server

    Lozanov, Kaloian D

    2016-01-01

    We calculate particle production during inflation and in the early stages of reheating after inflation in models with a charged scalar field coupled to Abelian and non-Abelian gauge fields. A detailed analysis of the power spectra of primordial electric fields, magnetic fields and charge fluctuations at the end of inflation and preheating is provided. We carefully account for the Gauss constraints during inflation and preheating, and clarify the role of the longitudinal components of the electric field. We calculate the timescale for the back-reaction of the produced gauge fields on the inflaton condensate, marking the onset of non-linear evolution of the fields. We provide a prescription for initial conditions for lattice simulations necessary to capture the subsequent nonlinear dynamics. On the observational side, we find that the primordial magnetic fields generated are too small to explain the origin of magnetic fields on galactic scales and the charge fluctuations are well within observational bounds for...

  16. Mechanical Properties, Surface Structure, and Morphology of Carbon Fibers Pre-heated for Liquid Aluminum Infiltration

    Science.gov (United States)

    Kachold, Franziska S.; Kozera, Rafal; Singer, Robert F.; Boczkowska, Anna

    2016-04-01

    To efficiently produce carbon fiber-reinforced aluminum on a large scale, we developed a special high-pressure die casting process. Pre-heating of the fibers is crucial for successful infiltration. In this paper, the influence of heating carried out in industrial conditions on the mechanical properties of the fibers was investigated. Therefore, polyacrylonitrile-based high-tensile carbon fiber textiles were heated by infrared emitters in an argon-rich atmosphere to temperatures between 450 and 1400 °C. Single fiber tensile tests revealed a decrease in tensile strength and strain at fracture. Young's modulus was not affected. Scanning electron microscopy identified cavities on the fiber surface as the reason for the decrease in mechanical properties. They were caused by the attack of atmospheric oxygen. The atomic structure of the fibers did not change at any temperature, as x-ray diffraction confirmed. Based on these data, the pre-heating for the casting process can be optimized.

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

    OpenAIRE

    Y.Ashok Kumar Reddy; B. V. Appa Rao

    2014-01-01

    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 dir...

  18. X-ray absorption lines - Signature for preheat level in non-explosive laser implosions

    Science.gov (United States)

    Yaakobi, B.; McCrory, R. L.; Skupsky, S.; Delettrez, J. A.; Bourke, P.; Soures, J. M.; Hooper, C. F.; Deckman, H.

    1980-08-01

    The measured X-ray spectrum from thick glass shells imploded with two TW six-beam laser pulses displayed absorption by transitions of Si ions. This indicates the existence around the time of peak compression of a cooler (less than approximately 200 eV) layer surrounding the hot innermost glass layer, of density times thickness approximately 0.0006 g/sq cm. This temperature is indicative of the preheat level ealier in the implosion.

  19. Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

    International Nuclear Information System (INIS)

    Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be 133Xe, and 198Au (on carbonized resin or as an aqueous colloidal suspension) will be used as the slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing

  20. Formation of disk galaxies in preheated media: a preventative feedback model

    CERN Document Server

    Lu, Yu; Wechsler, Risa H

    2014-01-01

    We introduce a semi-analytic galaxy formation model implementing a self-consistent treatment for the hot halo gas configuration and the assembly of central disks. Using the model, we explore a preventative feedback model, in which the circum-halo medium is assumed to be preheated up to a certain entropy level by early starbursts or other processes, and compare it with an ejective feedback model, in which baryons are first accreted into dark matter halos and subsequently ejected out by feedback. The model demonstrates that when the medium is preheated to an entropy comparable to the halo virial entropy the baryon accretion can be largely reduced and delayed. In addition, the preheated medium can establish an extended low density gaseous halo when it accretes into the dark matter halos, and result in a specific angular momentum of the cooling gas large enough to form central disks as extended as those observed. Combined with simulated halo assembly histories, the preventative feedback model can reproduce remark...

  1. Tekken testing to determine the preheating temperature on ASTM A514 GR B steel

    International Nuclear Information System (INIS)

    The cold cracking test methods are used to determine the preheating temperature in order to avoid cracking in steel welding.In this work Tekken tests on high strength quenching and tempering (ASTM A514 GrB) structural steel with a thickness of 25 mm have been made.The welds were done using a FCAW process with gas shielding and basic low hydrogen cored wire E 110T5-K4.The welding parameters and joint design applied in this work are similar to the ones used on site production.The base metal, HAZ and weld metal microstructure have been evaluated by optical and SEM microscopy.Thermal cycles records of each welding have been made to relate preheat temperature with the cooling time on the range of 800-500 degC (t8/5) or 800-100degC (t8/1) and the evidence of crack or no crack condition.Finally, a preheat temperature of 150degC and the cooling time larger than 17 s improve a welding integrity without cracks

  2. 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.

  3. Phase change material thermal storage for biofuel preheating in micro trigeneration application: A numerical study

    International Nuclear Information System (INIS)

    Highlights: • Engine exhaust heat driven phase change material thermal storage. • Fuel preheating for direct use of straight plant oil on diesel engine. • CFD aided design of the phase change material thermal storage. • Melting and solidification model considering natural convection. - Abstract: A biofuel micro trigeneration prototype has been developed to utilise local energy crop oils as fuel in rural areas and developing countries. Straight plant oils (SPOs) only leave behind very little carbon footprint during its simply production process compared to commercial biodiesels in refineries, but the high viscosity of SPOs causes difficulties at engine cold starts, which further results in poor fuel atomisation, compromised engine performance and fast engine deterioration. In this study, a phase change material (PCM) thermal storage is designed to recover and store engine exhaust heat to preheat SPOs at cold starts. High temperature commercial paraffin is selected as the PCM to meet the optimal preheating temperature range of 70–90 °C, in terms of the SPO property study. A numerical model of the PCM thermal storage is developed and validated by references. The PCM melting and solidification processes with the consideration of natural convection in liquid zone are simulated in ANSYS-FLUENT to verify the feasibility of the PCM thermal storage as a part of the self-contained biofuel micro trigeneration prototype

  4. Influence of preheating by infrared radiation on the moisture content of rye grains during the moistening process

    International Nuclear Information System (INIS)

    Paper presents the results of studies on the moisture content in rye grains, not heated, and heated by infrared radiation, during the moistening process. The grains were preheated by infrared radiation and then they were moistened at different temperatures. The final moisture content was tested during the moistening process. Rye grains preheated by infrared radiation had higher moisture content than the unheated grains. The Peleg model is useful to describe the changes of moisture content during the moistening process. (author)

  5. Perubahan Preheat Zone Thickness dan Bilangan Karlovitz pada Fenomena Flame lift-up Pembakaran Premix Gas Propana

    OpenAIRE

    I Made Kartika Dhiputra; Bambang Sugiarto; Yulianto S. Nugroho; Cokorda Prapti Mahandari

    2009-01-01

    It has been found a phenomenon of flame lift-up on the experiment employing a Bunsen burner. Flame lift-up is the occurrence of flame jumping from the tip burner to the ring that inserting above the burner. Fundamental research on flames did not elaborate the cause of flame jumping. Using flame stretch approach, an initial research on dimensionless number to predict the occasion of this phenomenon was discussed to determine preheat zone thickness and Karlovitz number. Preheat zone thickness w...

  6. Heat transfer intensification within tube recuperator by inserting secondary emitters inside air channels

    International Nuclear Information System (INIS)

    The research program was stipulated by reduction the service life of the tube recuperators of reheating furnaces at DUNAFERR metallurgical works in Dunaujvaros (Hungary) while replacement the natural gas by coke - oven gas as a furnace fuel took place and air preheating temperature was increased. The tests procedure consists in comparison of temperature and pressure distributions by air flows preheating under air moving inside the tube loops. Advantages of new recuperator design compared to ordinary one have been proven by validation of concept for adequacy to the testing results. The first tests have demonstrated enhancement of local specific and total heat fluxes transferred from flue gases to air flow within the MD tube loops in comparison with those for BD loops by 25 to 45% - dependence on temperature level within the heating (furnace) chamber and on preheated air flow rate. (author)

  7. 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).

  8. 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

  9. Enhancement of machinability by workpiece preheating in end milling of Ti-6Al-4V

    OpenAIRE

    Hossain, M. I.; Nurul Amin, A. K. M.; A.U. Patwari; Karim, A.

    2008-01-01

    Purpose: The main objective of this paper is to investigate the effect of workpiece preheating with high frequency induction heating on improvement of machinability of Ti-6Al-4V during end milling using PVD TiAlN coated inserts. Tool life, cutting force and vibration were investigated during the experiments.Design/methodology/approach: End milling tests were conducted on Vertical Machining Centre (VMC ZPS, Model: MCFV 1060 with quarter immersion cutting. Titanium based alloy Ti-6Al-4V bar was...

  10. The Chemo-Dynamical Evolution of Elliptical Galaxies: Pre-heating and AGN heating

    CERN Document Server

    Kawata, D; Gibson, Brad K.; Kawata, Daisuke

    2004-01-01

    We study the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution cosmological simulations. Our Tree N-body/SPH code includes a self-consistent treatment of radiative cooling, star formation, supernovae feedback, and chemical enrichment. We present a series of LCDM cosmological simulations which trace the spatial and temporal evolution of abundances of heavy elements in both the stellar and gas components of galaxies. A giant elliptical galaxy formed in one of the simulations is quantitatively compared with the observational data in both the X-ray and optical regime. We implement a treatment of both pre-heating and AGN heating in this simulation, and examine the effect of these processes on elliptical galaxy formation. We find that the adopted pre-heating (T=10^7 K at z=4) is not strong enough to explain the observed X-ray or optical properties. On the other hand, our AGN heating model in which the gas inflow induces the AGN heating is consistent with bo...

  11. The charged inflaton and its gauge fields: preheating and initial conditions for reheating

    Science.gov (United States)

    Lozanov, Kaloian D.; Amin, Mustafa A.

    2016-06-01

    We calculate particle production during inflation and in the early stages of reheating after inflation in models with a charged scalar field coupled to Abelian and non-Abelian gauge fields. A detailed analysis of the power spectra of primordial electric fields, magnetic fields and charge fluctuations at the end of inflation and preheating is provided. We carefully account for the Gauss constraints during inflation and preheating, and clarify the role of the longitudinal components of the electric field. We calculate the timescale for the back-reaction of the produced gauge fields on the inflaton condensate, marking the onset of non-linear evolution of the fields. We provide a prescription for initial conditions for lattice simulations necessary to capture the subsequent nonlinear dynamics. On the observational side, we find that the primordial magnetic fields generated are too small to explain the origin of magnetic fields on galactic scales and the charge fluctuations are well within observational bounds for the models considered in this paper.

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

    Science.gov (United States)

    Laffite, S.; Baton, S. D.; Combis, P.; Clerouin, J.; Koenig, M.; Recoules, V.; Rousseaux, C.; Videau, L.

    2014-08-01

    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.

  13. 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.

  14. Correlation between preheating and crack prevention in the welding of unalloyed high-strength fine-grained structural steels

    International Nuclear Information System (INIS)

    The paper discusses the problem of how to find the right preheating temperature in the welding of unalloyed, fine-grained high-strength structural steels. Possibilities are critically evaluated with the result that Uwer's formulas for the calculation of heat removal are well suited for a determination of the necessary preheating for the welding process. This is illustrated by some of the author's own experiments. On the basis of this newly gained knowledge, a revision of the 1976 iron and steel material sheet No.W088 is proposed. (orig./IHOE) 891 IHOE/orig. 892 MKO

  15. Effect of the Preheating Temperature on Process Time in Friction Stir Welding of Al 6061-T6

    DEFF Research Database (Denmark)

    Jabbari, Masoud

    2013-01-01

    This paper presents the results obtained and the deductions made from an analytical modeling involving friction stir welding of Al 6061-T6. A new database was developed to simulate the contact temperature between the tool and the workpiece. A second-order equation is proposed for simulating the...... temperature in the contact boundary and the thermal history during the plunge phase. The effect of the preheating temperature on the process time was investigated with the proposed model. The results show that an increase of the preheating time leads to a decrease in the process time up to the plunge and the...

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

    International Nuclear Information System (INIS)

    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/m2 or 0.75 MJ/m2, 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.

  17. Fouling of preheat exchanger train in a crude oil distillation unit

    Energy Technology Data Exchange (ETDEWEB)

    Masri, M.A. [Refining and Petrochemical Dept., Algerian Institue of Petroleum, Boumerdes (Algeria)

    2000-07-01

    Fouling continues to be one of the primary problems plaguing designers and operators of heat transfer equipment systems. In oil refinery, fouling leads to enormous financial penalties in terms of increased capital costs and additional energy consumption due to loss of throughput, shutdowns costs, maintenance costs for cleaning and antifoulants chemical treatments. Preliminary results of pressure drop measurements of a crude oil preheat exchanger train as a function of time duration is reported. Analysis and interpretation on the plant data will be used to determine optimum cleaning cycles. A research project on crude oil distillation unit in a laboratory is carried out to investigate the parameters that affect fouling tendency. The goals are to provide methods for controlling oil refinery fouling, develop analytical expressions that describe the dynamic behaviour and so determine the economic fouling resistances. (authors)

  18. Preheating in the Standard Model with the Higgs-Inflaton coupled to gravity

    CERN Document Server

    Garcia-Bellido, Juan; Rubio, Javier

    2008-01-01

    We study the details of preheating in an inflationary scenario in which the Standard Model Higgs, strongly non-minimally coupled to gravity, plays the role of the inflaton. We find that the Universe does not reheat immediately through perturbative decays, but rather initiate a complex process in which perturbative and non-perturbative effects are mixed. The Higgs condesate starts oscillating around the minimum of its potential, producing W and Z gauge bosons non-perturbatively, due to violation of the so-called adiabaticity condition. However, during each semi-oscillation, the created gauge bosons completely decay (perturbatively) into fermions. This way, the decay of the gauge bosons prevents the development of parametric resonance, since bosons cannot accumulate significantly at the beginning. However, the energy transferred to the decay products of the bosons is not enough to reheat the universe, so after about a hundred oscillations, the resonance effect will finally dominate over the perturbative decays....

  19. Single pass hybrid laser–MIG welding of 4-mm thick copper without preheating

    International Nuclear Information System (INIS)

    Highlights: • For the first time, hybrid laser–arc welding is used in copper joining process. • Butt welding of 4-mm copper is achieved at high speed and without preheating. • Defect-free joint is obtained in butt-joint configuration with a right gap size. • Laser–MIG hybrid welding is a feasible, efficient welding method for copper. - Abstract: Laser–arc hybrid welding of highly reflective T2 copper was conducted and significant synergy effect was observed. Effects of primary welding parameters on the shape and integrity of copper joints were studied through bead-on-plate (BOP) welding test. Results of X-ray inspection and infrared photography showed that both porosity susceptibility and crack susceptibility were highly dependent on welding heat input or energy coupling efficiency, but had totally different trend, which narrowed the process window of BOP welding of copper. Hot crack and porosity were successfully suppressed by using a square butt joint configuration with a proper gap size. A 4-mm thick, defect-free butt joint was obtained by single-pass hybrid welding at a speed of 1.3 m/min without preheating the work piece. The microstructure, microhardness, mechanical properties and tensile fracture surface of the butt joint obtained were studied. Tensile strength and elongation rate of the butt joint obtained were about 87% and 56% of that of base metal, respectively. The lowered mechanical properties of butt welded copper joint were related to the softening of fusion zone (FZ) and its vicinity, the coarse microstructure in FZ and heat affected zone (HAZ), and the possible concentration of impurity elements at the central region of FZ

  20. Optimization of injection timing and injection pressure of a DI diesel engine fueled with preheated rice bran oil

    Directory of Open Access Journals (Sweden)

    R. Raghu1, G. Ramadoss

    2011-07-01

    Full Text Available In the present study experiments were carried out in a constant speed, stationary direct injection diesel engine and the performance was investigated. Initially the engine fueled with diesel, rice bran biodiesel (methyl ester, raw rice bran oil and preheated rice bran oil with standard injection timing and injection pressures at different load conditions and the performances were compared. With the help of a heat exchanger and using the exhaust gases, the rice bran oil was preheated. It was found that the pre heated rice bran oil exhibits a closer performance as compared to rice bran biodiesel. Then the injection timing and injection were varied and the performance and emission parameters were investigated using preheated rice bran oil. It was found that the brake thermal efficiency and oxides of nitrogen were found to be higher and BSFC and smoke were found to be lower at 21° CA bTDC of injection timing and 230 bar injection pressure. From the test results the optimum injection timing and injection timing for the engine fueled with preheated rice bran oil were evaluated.

  1. 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.

  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. PMID:26037967

  3. Phase structure development as preheating UHMWPE powder temperature changes in the micro-UPM process

    Science.gov (United States)

    Liang, Xiong; Wu, Xiaoyu; Xu, Bin; Ma, Jiang; Liu, Zhiyuan; Peng, Taijiang; Fu, Lianyu

    2016-01-01

    In this study, using high-speed mechanical drilling on printed circuit boards (PCBs) with two micro carbide drill bits with diameters of 0.15 mm and 0.20 mm, two different PCB micro-cylinder array inserts are fabricated using the micro-ultrasonic powder moulding (micro-UPM) process. According to the temperature curves recorded by a measurement module, when viscoelastic heating dominated, the temperature increasing rate was about three times the rate when interfacial friction heating dominated. From the differential scanning calorimetry and nanoindentation test results, if the ultra-high molecule weight polyethylene (UHMWPE) powder was not preheated, then the micro-cylinder array polymer parts generally consisted of nascent and melt-recrystallised phases as a whole. However, when the micro-cavity and compressed UHMWPE powder grew from room temperature of 28 °C to 85 °C, the two-phase structure gradually developed into a single melt-recrystallised phase. According to single-crystal x-ray diffraction test results, the crystallinity of the base region of the micro-UPM cylinder array part is higher than that of the micro-cylinder region, whereas the grain size of the (1 1 0) crystal surface is larger than that of the (2 0 0) crystal surface.

  4. 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.

  5. Dismantling and decontamination of the tube bundle of a feedwater preheater of the Garigliano BWR

    International Nuclear Information System (INIS)

    The report deals with dismantling and decontamination of the tube bundle of a feedwater preheater of Garigliano-BWR. Decontamination is a common practice in decommissioning works and it can be used both for reducing radiation exposures, in order to save manrem, and for the unrestricted release of materials. In this latter field the decontamination of tube bundle is a particular case because of their large contaminated surfaces and relatively low weight; at the moment no decon technique was available on the market to decontaminate up to the unrestricted release the materials of tube bundles. In this context an innovative decon technique using aggressive chemicals together with ultrasounds in a tank, was developed by several laboratories and assessed with in-scale testings. A decon procedure considering two phases: first with ultrasounds applied in water at 600C, and second with ultrasounds applied in a solution of HF/HNO3 acids at 60-700C, was qualified. The demonstration of the performances of the new technique under real conditions was made by performing ten full-scale demo tests, each one on an assembly of 100 straight tubes, 1 m long each, for a total of 1000 meters

  6. 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).

  7. Effects of Preheating on X-ray Scaling Relations in Galaxy Clusters

    CERN Document Server

    Bialek, J J; Mohr, J J; Bialek, John J.; Evrard, August E.; Mohr, Joseph J.

    2000-01-01

    The failure of purely gravitational models of X-ray cluster formation to reproduce basic observed properties of the local cluster population suggests the need for one or more additional physical processes operating on the intracluster medium (ICM). We present results from 84 moderate resolution gas dynamic simulations designed to systematically investigate the effects of preheating - an initially elevated ICM adiabat - on the resultant, local X-ray size-temperature, luminosity-temperature and ICM mass-temperature relations. Seven sets of twelve simulations are performed for a LambdaCDM cosmology, each set characterized by a different initial entropy level S_i. The slopes of the observable relations steepen monotonically as S_i is increased. Observed slopes for all three relations are reproduced by models with S_i: 55-150 keV cm^2, levels that compare favorably to empirical determinations of core ICM entropy by Lloyd-Davies, Ponman & Cannon. The redshift evolution for the case of a locally successful model...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Arvind Atreya

    2007-02-16

    This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.

  13. Effect of the Preheating Temperature on Process Time in Friction Stir Welding of Al 6061-T6

    OpenAIRE

    Masoud Jabbari

    2013-01-01

    This paper presents the results obtained and the deductions made from an analytical modeling involving friction stir welding of Al 6061-T6. A new database was developed to simulate the contact temperature between the tool and the workpiece. A second-order equation is proposed for simulating the temperature in the contact boundary and the thermal history during the plunge phase. The effect of the preheating temperature on the process time was investigated with the proposed model. The results s...

  14. Effect of Varying Mixing Ratios and Pre-Heat Temperature on the Mechanical Properties of Polyurethane (PU) Foam

    OpenAIRE

    Oppon, Charles; Hackney, Philip; Shyha, Islam; Birkett, Martin

    2015-01-01

    The continuous growth of the usage of Polyurethane foams requires that designers and manufacturers investigate the appropriate factors that affect their production and full usage in order to exploit their full potential. This research reports the effects of the mixing ratio of the main constituents (polyol and diisocyanate) which form the polyurethane foams and different pre-heat temperatures of the separate chemicals before mixing. The work has documented that there is a significant reductio...

  15. Numerical simulation of temperature field during gas preheating and start-up of drained aluminum reduction cell

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ping; WANG Zhi-qi; ZHOU Nai-jun

    2006-01-01

    The method of numerical simulation was applied to investigate gas preheating and start-up process in a drained aluminum reduction cell. The transient temperature and velocity fields of a 156 kA drained aluminum reduction cell were numerically calculated. The results show that the method of gas preheating and bake-out can basically meet the technical requirements of the start-up process for the drained cell. If the same distributing scheme of gas nozzle as that in the general cells is used, there are problems of great temperature gradients and low temperature zone at the top of cathode near the side of nozzles. In order to promote the effect of gas preheating and baking the drained cell, the jetting angle of end nozzle is adjusted and the temperature distribution in the drained cell is obviously improved. By means of simulating the temperature field in the case that jetting angle varies from 0° to 30°, it is concluded that better temperature distribution can be obtained if the jetting angle of end nozzle is approximately 15°.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-15

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

  17. Micro distributed energy system driven with preheated Croton megalocarpus oil – A performance and particulate emission study

    International Nuclear Information System (INIS)

    Highlights: • Promising Croton megalocarpus oil preheated and directly applied on engine. • A direct plant oil firing micro trigeneration developed for domestic sector. • Study the particulate emission of the engine with direct plant oil firing. • Reveal the fundamental reasons for the performance and emission variation. - Abstract: As a carbon neutral biofuel, the cold pressed Croton megalocarpus oil (CMO) has the nature of easy production without any further chemical process, but suffers for its high viscosity and poor atomisation if being applied on the compression-ignition (CI) engine generator. A micro distributed energy system comprised of a modified 6.5 kWe CI engine generator and an engine exhaust driven diffusion absorption refrigerator has been set up for domestic application, which applies both diesel and CMO. To minimise the negative impact of fuel properties of CMO, the temperature before injection has been elevated with the trace heater and the waste heat from the engine. The performance of the preheated CMO up to 90 °C on the engine generator system reflects an improvement of the atomisation and combustion in the cylinder compared to the non-preheated CMO. The particulate emission test reveals the similarity of both the total number and the total weigh of the particulates emitted from the engine generator system running on diesel and CMO in 90 °C

  18. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    Energy Technology Data Exchange (ETDEWEB)

    Šturm, Roman, E-mail: roman.sturm@fs.uni-lj.si [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Štefanikova, Maria [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Steiner Petrovič, Darja [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia)

    2015-01-15

    Graphical abstract: - Highlights: • Heat-treatment protocol for laser surface melting of cold-work tool steel is proposed. • The laser melted steel surface is hardened, and morphologically modified. • The pre-heating of substrate creates a crack-and pore-free steel surface. • The optimum pre-heating temperature is determined to be 350 °C. • Using pre-heating the quantity of retained austenite is reduced. - Abstract: In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides.

  19. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Heat-treatment protocol for laser surface melting of cold-work tool steel is proposed. • The laser melted steel surface is hardened, and morphologically modified. • The pre-heating of substrate creates a crack-and pore-free steel surface. • The optimum pre-heating temperature is determined to be 350 °C. • Using pre-heating the quantity of retained austenite is reduced. - Abstract: In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides

  20. 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

    ‘The Cube’. 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...

  1. Investigation on gasoline homogeneous charge compression ignition (HCCI) combustion implemented by residual gas trapping combined with intake preheating through waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • Combined use of residual gas trapping and intake preheating is explored. • Fuel economy improvement benefits most from changed valve configuration. • Compromise between intake thermal demand and engine efficiency is analyzed. • Intake preheating by waste heat recovery decreases fuel consumption by 8–12%. • Low load boundary is effectively extended to 0.8 bar. - Abstract: Homogeneous charge compression ignition (HCCI) combustion achieved by residual gas trapping suffers from the limitation of the low load extension and fuel economy penalties whilst achieved by intake preheating alone is limited by the high intake thermal requirement and waste heat recovery. In the presented research, systematic engine experiments were carried out on a single cylinder engine on the combined use of residual gas trapping and intake preheating to achieve optimized combustion and better fuel conversion efficiency in the HCCI operational range. The effect of different combinations between residual gas trapping and intake preheating on HCCI combustion was explored and analyzed. It was indicated that the implementation transition from residual gas trapping to intake preheating significantly influenced the fuel economy and emissions. The decreased loss resulting from changed valve configuration contributed much more than half of the fuel economy improvement. The variation in emissions depended both on the combustion temperature influenced by dilution charge and the in-cylinder distribution affected by implementation form. It was also demonstrated that the increased benefit became less when the intake temperature further went up. Thus a relatively reasonable compromise between intake thermal demand and engine efficiency could be achieved to optimize the HCCI combustion by combining waste heat recovery and residual gas trapping. Compared to negative valve overlap method alone, the supplementary of intake preheating by waste heat recovery provided 8–12% fuel economy

  2. 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.

  3. Steam generator and preheater tube ID fouling and the impact on reactor inlet header temperature and eddy current inspections

    International Nuclear Information System (INIS)

    Materials selection is an important consideration in new build and refurbishment of Heavy Water Reactors (HWR). This paper will focus on the impacts of the deposit of magnetite on the tube ID of steam generators and preheater. Bruce Power OPEX is being shared to illustrate the importance of materials selection. The deposit of magnetite on the tube ID of steam generators (SG) and preheater (PH) has two significant impacts that will be presented. Firstly, the degradation in SG and PH thermal performance causes a rise in the reactor inlet header temperature (RIHT). This rising trend continues unabated as long as deposits on the tube ID continues. If not managed this may result in loss of production due to the RIHT limits being reached. Mitigating actions such as tube ID cleaning is only a temporary solution as it does not stop the root cause which is feeder flow accelerated corrosion (FAC). Secondly, deposit of magnetite on the tube ID of steam generators (SG) and preheater (PH) has an impact on tube inspections as required by CSA N285.4. There are two impacts on SG and PH inspections. ID deposits reduces the clearance for eddy current probes in the tubes and make it more difficult to acquire inspection data. Additionally, tube ID deposits can reduce the effectiveness to detect and size flaws in the SG and PH tubes. Both issues make eddy current inspection a challenge for the utilities. These impacts affect the operation and inspection and maintenance of CANDU nuclear power plants at Bruce Power. Where possible these issues should be addressed in any future new build or refurbishment of HWR power plants. (author)

  4. Mitigation of fouling in refinery pre-heat trains by optimal management of cleaning and antifoulant treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, D.I.; Smaili, F.; Vassiliadis, V.S. [Dept. of Chemical Engineering, Cambridge (United Kingdom)

    2000-08-01

    Mitigation of fouling on a refinery heat exhanger network by optimising the cleaning schedule is demonstrated using a case study based on a refinery distillation pre-heat train. The scheduling problem is formulated as a mixed integer non-linear programming (MINLP) problem and solved using two different approaches. The results for a 3 year case study involving 27 exchangers illustrate the nature of this optimisation problem. The results for a 3.5 year operating horizon are discussed in terms of mitigation strategies, including the alternative use of antifoulant chemicals. (au)

  5. Depression of hyperthermic potentiation in cell killing of ultraviolet light-irradiated Dictyostelium discoideum by pre-heat treatment

    International Nuclear Information System (INIS)

    Heat treatment at 300C for 15 min immediately after ultraviolet (UV) irradiation enhanced cell killing of Dictyostelium discoideum. However, when the cells were heated at 300C for 15 min and then cultured for more than 10 min at 230C prior to UV exposure, the hyperthermic potentiation in cell killing was depressed. When these preheated cells were cultured in the presence of cycloheximide, the depression of the hyperthermic potentiation disappeared. These results suggest that the depression in hyperthermic potentiation may be the result of the induction of some heat-shock-type proteins. (author)

  6. Performance of Pulverized Coal Combustion under High Temperature Air Diluted by Steam

    OpenAIRE

    Mohsen Saffari Pour; Yang Weihong

    2014-01-01

    The high temperature air combustion (HiTAC) is an advanced promising technology for heat recovery, energy saving, and stability improvement of flame. Computational fluid dynamic (CFD) is known as an applied tool to execute HiTAC modeling. In this paper, performances of pulverized coal combustion under the high preheated and oxygen deficient air are studied by both experimental and numerical methodology. The experimental facilities have been accomplished in a HiTAC chamber with coal injection ...

  7. A Review on Effect of Preheating and/or Post Weld Heat Treatmemt (Pwht on Mechanical Behaviour of Ferrous Metals.

    Directory of Open Access Journals (Sweden)

    Bipin Kumar Srivastava,

    2010-04-01

    Full Text Available Welding is used in ships, bridges, pressure vessels, industrial machinery, automobile, rolling stock and manyother fields. Problems associated with welding are common issues in these fields. Weldability of steel refers tothe maximum hardness of the heat affected zone (HAZ and the cold cracking susceptibility of welds. Whensteel is welded non uniform heating and cooling in weld metal and in base metal generates harder Heat AffectedZone (HAZ, cold crack susceptibility and residual stress in weldment. The best way to minimize above difficulties is to slow the heating and cooling rate of the base metal and weld heat affected zone. However there are many methods for reducing the effects of above problems and one of them is preheating and/or post heating. Pre heating and/or Post heating have been widely employed in welding operation for preventing cold cracking. This paper presents the effect of preheating and/or PWHT on mechanical behaviour or maximum HAZ hardness, cold cracking susceptibility and residual stresses of various steel types.

  8. Importance of atomic oxygen in preheating zone in plasma-assisted combustion of a steady-state premixed burner flame

    Science.gov (United States)

    Zaima, K.; Akashi, H.; Sasaki, K.

    2015-09-01

    It is widely believed that electron impact processes play essential roles in plasma-assisted combustion. However, the concrete roles of high-energy electrons have not been fully understood yet. In this work, we examined the density of atomic oxygen in a premixed burner flame with the superposition of dielectric barrier discharge (DBD). The density of atomic oxygen in the reaction zone was not affected by the superposition of DBD, indicating that the amount of atomic oxygen produced by combustion reactions was much larger than that produced by electron impact processes. On the other hand, in the preheating zone, we observed high-frequency oscillation of the density of atomic oxygen at the timings of the pulsed current of DBD. The oscillation suggests the rapid consumption of additional atomic oxygen by combustion reactions. A numerical simulation using Chemkin indicates the shortened ignition delay time when adding additional atomic oxygen in the period of low-temperature oxidation. The present results reveals the importance of atomic oxygen, which is produced by the effect of high-energy electrons, in the preheating zone in plasma-assisted combustion of the steady-state premixed burner flame.

  9. Measurement of Preheat and Shock Melting in Be Ablators During the First Few ns of the NIF Ignition Pulse

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D K; Prisbrey, S T; Page, R H; Braun, D G; Edwards, M J; Hibbard, R L; Moreno, K A; Mauldin, M P; Nikroo, A

    2008-05-28

    We have developed a scaled hohlraum platform to experimentally measure preheat in ablator materials during the first few nanoseconds of the radiation drive proposed for ignition experiments at the National Ignition Facility [J. A. Paisner, J. D. Boyes, S. A. Kumpan, et al., Laser Focus World 30, 75 (1994)]. The platform design approximates the radiation environment of the pole of the capsule by matching both the laser spot intensity and illuminated hohlraum wall fraction in scaled halfraums driven by the OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton, et al., Optics Communications 133, 495 (1997)]. A VISAR reflecting from the rear surface of the sample was used to measure sample motion prior to shock breakout. The experiments show that the first {approx}20 {micro}m of a Be ablator will be melted by radiation preheat, with subsequent material melted by the initial shock, in agreement with simulations. The experiments also show no evidence of anomalous heating of buried high-z doped layers in the ablator.

  10. Experimental study on the operating characteristics of an inner preheating transpiring wall reactor for supercritical water oxidation: Temperature profiles and product properties

    International Nuclear Information System (INIS)

    A new process to generate multiple thermal fluids by supercritical water oxidation (SCWO) was proposed to enhance oil recovery. An inner preheating transpiring wall reactor for SCWO was designed and tested to avoid plugging in the preheating section. Hot water (400–600 °C) was used as auxiliary heat source to preheat the feed to the reaction temperature. The effect of different operating parameters on the performance of the inner preheating transpiring wall reactor was investigated, and the optimized operating parameters were determined based on temperature profiles and product properties. The reaction temperature is close to 900 °C at an auxiliary heat source flow of 2.79 kg/h, and the auxiliary heat source flow is determined at 6–14 kg/h to avoid the overheating of the reactor. The useful reaction time is used to quantitatively describe the feed degradation efficiency. The outlet concentration of total organic carbon (TOCout) and CO in the effluent gradually decreases with increasing useful reaction time. The useful reaction time needed for complete oxidation of the feed is 10.5 s for the reactor. - Highlights: • A new process to generate multiple thermal fluids by SCWO was proposed. • An inner preheating transpiring wall reactor for SCWO was designed and tested. • Hot water was used as auxiliary heat source to preheat the feed at room temperature. • Effect of operating parameters on the performance of the reactor was investigated. • The useful reaction time required for complete oxidation of the feed is 10.5 s

  11. High aspect ratio hard x-ray (> 100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Doppner, T; Dewald, E; Divol, L; Burns, S; Izumi, N; Kline, J; LaCaille, G; McNaney, J; Prasad, R; Thomas, C A; Glenzer, S H; Landen, O; Author, A; Author, S G; Author, T

    2012-05-01

    We have fielded a multi-pinhole, hard x-ray (> 100 keV) imager 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 that could limit the compressibility required for ignition and burn. Our hard x-ray imaging measurements allow to set an upper limit to the DT fuel preheat, which we find is acceptable in current capsule implosions on the NIF.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  13. New operating strategies for molten salt in line focusing solar fields - Daily drainage and solar receiver preheating

    Science.gov (United States)

    Eickhoff, Martin; Meyer-Grünefeldt, Mirko; Keller, Lothar

    2016-05-01

    Nowadays molten salt is efficiently used in point concentrating solar thermal power plants. Line focusing systems still have the disadvantage of elevated heat losses at night because of active freeze protection of the solar field piping system. In order to achieve an efficient operation of line focusing solar power plants using molten salt, a new plant design and a novel operating strategy is developed for Linear Fresnel- and Parabolic Trough power plants. Daily vespertine drainage of the solar field piping and daily matutinal refilling of the solar preheated absorber tubes eliminate the need of nocturnal heating of the solar field and reduce nocturnal heat losses to a minimum. The feasibility of this new operating strategy with all its sub-steps has been demonstrated experimentally.

  14. Ignition of Deflagration and Detonation Ahead of the Flame due to Radiative Preheating of Suspended Micro Particles

    CERN Document Server

    Ivanov, M F; Liberman, M A

    2014-01-01

    We study a flame propagating in the gaseous combustible mixture with suspended inert solid micro particles. The gaseous mixture is assumed to be transparent for thermal radiation emitted by the hot combustion products, while particles absorb and reemit the radiation. Thermal radiation heats the particles, which in turn transfer the heat to the surrounding unburned gaseous mixture by means of thermal heat transfer. Different scenarios are possible depending on the spatial distribution of the particles, their size and the number density. In the case of uniform spatial distribution the radiation absorption ahead of the flame causes a modest increase of the combustion wave velocity. On the contrary, in the case of non-uniform distribution of the particles, such that the particles number density increases far ahead of the flame, the preheating caused by the thermal radiation may trigger additional source of ignition. Far enough ahead of the flame, where number density of particles is higher, the temperature due to...

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

    International Nuclear Information System (INIS)

    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)

  16. A modelling approach for the assessment of an air-dryer economic feasibility for small-scale biomass steam boilers

    OpenAIRE

    De Fusco, Lucio; Jeanmart, Hervé; Blondeau, Julien

    2015-01-01

    Fuel drying is an energetically and economically expensive pretreatment process, which may not be worth the investment in the case of small-scale generation plants. This paper presents an investigation on the air dryer feasibility to enhance the operation of biomass steam boiler. In the proposed approach, the external drying technology using preheated air and the biomass steam production system is modelled in terms of energy and an economical analysis. A focus is given to the system size infl...

  17. Experimental investigation of burning velocities of ultra-wet methane-air-steam mixtures

    OpenAIRE

    Albin, Eric; Nawroth, Holger; Göke, Sebastian; D'Angelo, Yves; Paschereit, Christian Oliver

    2013-01-01

    Global burning velocities of methane-air-steam mixtures are measured on prismatic laminar Bunsen flames and lifted turbulent V-flames for various preheating temperatures, equivalence ratios and steam mixture fractions at atmospheric pressure. Experiments are conducted on a new rectangular slot-burner. Experimental burning velocities are compared to computed flame speeds of one dimensional adiabatic premixed flames using detailed mechanisms (Konnov 0.5 and GRI Mech 3.0). Mean profiles of radic...

  18. NRC Information Notice No. 92-67: Deficiency in design modifications to address failures of Hiller actuators upon a gradual loss of air pressure

    International Nuclear Information System (INIS)

    On January 7, 1992, Carolina Power and Light Company (Shearon Harris Plant) components associated with the air supply to the actuators of the three main feedwater preheater bypass isolation valves were not qualified for a Q class application. Specifically, the failure of the air pump in the non-Q Class, non-seismic instrument air supply to the valve actuator accumulator could prevent pressure switches upstream of the air pump from detecting slow leakage in the Q Class, seismic portion of the actuator air lines. The pressure switches were installed to ensure valve closure by sending an automatic close signal if the instrument air system pressure (upstream of the actuator air pump) dropped to 66 psig as discussed in IN 82-25. The main feedwater preheater bypass isolation valves function as containment isolation valves upon receipt of a feedwater isolation signal. The function of the air pump is to raise the normal instrument air supply pressure from 70 to 100 psig to approximately 150 psig. If accumulator pressure drops from 150 psig to 122 psig, the main feedwater preheater bypass isolation valve may not close within 10 seconds. If pressure drops to a value as low as 20 psig, it may not be sufficient to close the main feedwater preheater bypass isolation valve and keep it closed against the maximum differential pressure across the valve seat. Upon discovery of this condition, Shearon Harris established a surveillance interval for verifying that the actuators' components were functioning properly and that the accumulators were fully pressurized. On January 12, 1992, non-Q components were replaced with suitable components and testing was completed satisfactorily

  19. 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.

  20. Performance and emissions characteristics of Jatropha oil (preheated and blends) in a direct injection compression ignition engine

    International Nuclear Information System (INIS)

    The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from triglycerides (vegetable oils/animal fats) present promising ''greener'' substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO2 emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel. In the present research, experiments were designed to study the effect of reducing Jatropha oil's viscosity by increasing the fuel temperature (using waste heat of the exhaust gases) and thereby eliminating its effect on combustion and emission characteristics of the engine. Experiments were also conducted using various blends of Jatropha oil with mineral diesel to study the effect of reduced blend viscosity on emissions and performance of diesel engine. A single cylinder, four stroke, constant speed, water cooled, direct injection diesel engine typically used in agricultural sector was used for the experiments. The acquired data were analyzed for various parameters such as thermal efficiency, brake specific fuel consumption (BSFC), smoke opacity, CO2, CO and HC emissions. While operating the engine on Jatropha oil (preheated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations. However, for higher blend concentrations, performance and emissions were observed to be marginally inferior. (author)

  1. Reduction of the polycyclic aromatic hydrocarbon (PAH) content of charcoal smoke during grilling by charcoal preparation using high carbonisation and a preheating step.

    Science.gov (United States)

    Chaemsai, Suriyapong; Kunanopparat, Thiranan; Srichumpuang, Jidapa; Nopharatana, Montira; Tangduangdee, Chairath; Siriwattanayotin, Suwit

    2016-03-01

    Charcoal-grilling may lead to contamination of food with carcinogenic polycyclic aromatic hydrocarbons (PAHs) during the grilling process. The objective of this work was to determine the effect of charcoal preparation on 16 USEPA priority PAHs in the smoke produced during the grilling process. Firstly, mangrove charcoal was prepared at carbonisation temperatures of 500, 750 and 1000°C. The charcoal were then preheated by burning at 650°C. This preheating step is usually used to prepare hot charcoal for the grilling process in the food industry. In this study, charcoal was preheated at different burning times at 5, 20 min and 5 h, at which time partial and whole charcoal glowed, and charcoal was completely burnt, respectively. Finally, PAHs in the smoke were collected and determined by GC/MS. The result showed that charcoal prepared at a carbonisation temperature of 500°C had higher levels of PAHs released into the smoke. In contrast, charcoal produced at 750 and 1000°C had lower PAHs released for all burning times. In addition, PAHs released for 5, 20 min and 5 h of burning time were about 19.9, 1.2 and 0.7 µg g(-1) dry charcoal for charcoal produced at 500°C, and about 0.9-1.4, 0.8-1.2 and 0.15-0.3 µg g(-1) dry charcoal for charcoal produced at 750 and 1000°C, respectively. Therefore, this research suggests that food grilled using charcoal carbonised at a high temperature of about 750°C presents a lower risk of PAH contamination. In addition, in the preheating step, whole charcoal should fully glow in order to reduce the PAH content in charcoal before grilling. PMID:26785749

  2. Air Pollution

    Science.gov (United States)

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

  3. Air Pollution

    Science.gov (United States)

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

  4. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    Science.gov (United States)

    Šturm, Roman; Štefanikova, Maria; Steiner Petrovič, Darja

    2015-01-01

    In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides.

  5. 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.

  6. 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.

  7. 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 determi...

  8. Air Abrasion

    Science.gov (United States)

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  9. Preheating in Bubble Collision

    CERN Document Server

    Zhang, Jun

    2010-01-01

    In a landscape with metastable minima, the bubbles will inevitably nucleate. We show that when the bubbles collide, due to the dramatically oscillating of the field at the collision region, the energy deposited in the bubble walls can be efficiently released by the explosive production of the particles. In this sense, the collision of bubbles is actually high inelastic. The cosmological implications of this result are discussed.

  10. Influence of BladeCooling on the Efficiency of Humid Air Turbine

    Directory of Open Access Journals (Sweden)

    Janusz Skorek

    2000-03-01

    Full Text Available

    The influence of an open system blade cooling on the efficiency of the humid air turbine has been analyzed. It has been assumed that three stages of the turbine are cooled by means of compressed air taken from the outlet of the compressor. The thermodynamic analysis showed, that the deleterious impact of blade cooling results mainly from the irreversibility of mixing of cooling air with the working fluid. The influence of the blade cooling on the optimum operational parameters of HAT turbine (compression ratio, excess air, air humidity and preheated air temperature has been analyzed too.

    • This paper was presented at the ECOS’99 Conference in Tokyo, June 8-10, 1999 

  11. A packed bed dehumidifier/regenerator for solar air conditioning with liquid desiccants

    Science.gov (United States)

    Factor, H. M.; Grossman, G.

    1980-01-01

    A packed column air-liquid contactor has been studied in application to air dehumidification and regeneration in solar air conditioning with liquid desiccants. A theoretical model has been developed to predict the performance of the device under various operating conditions. Computer simulations based on the model are presented which indicate the practical range of air to liquid flux ratios and associated changes in air humidity and desiccant concentration. An experimental apparatus has been constructed and experiments performed with Monoethylene Glycol (MEG) and Lithium Bromide as desiccants. MEG experiments have yielded inaccurate results and have pointed out some practical problems associated with the use of Glycols. LiBr experiments show very good agreement with the theoretical model. Preheating of the air is shown to greatly enhance desiccant regeneration. The packed column yields good results as a dehumidifier/regenerator, provided pressure drop can be reduced with the use of suitable packing.

  12. 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

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

    Directory of Open Access Journals (Sweden)

    Jan T. Szargut

    2000-06-01

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

  14. Application of field synergy principle for optimization fluid flow and convective heat transfer in a tube bundle of a pre-heater

    International Nuclear Information System (INIS)

    The big problems facing solar-assisted MED (multiple-effect distillation) desalination unit are the low efficiency and bulky heat exchangers, which worsen its systematic economic feasibility. In an attempt to develop heat transfer technologies with high energy efficiency, a mathematical study is established, and optimization analysis using FSP (field synergy principle) is proposed to support meaning of heat transfer enhancement of a pre-heater in a solar-assisted MED desalination unit. Numerical simulations are performed on fluid flow and heat transfer characteristics in a circular and elliptical tube bundle. The numerical results are analyzed using the concept of synergy angle and synergy number as an indication of synergy between velocity vector and temperature gradient fields. Heat transfer in elliptical tube bundle is enhanced significantly with increasing initial velocity of the feed seawater and field synergy number and decreasing of synergy angle. Under the same operating conditions of the two designs, the total average synergy angle is 78.97° and 66.31° in circular and elliptical tube bundle, respectively. Optimization of the pre-heater by FSP shows that in case of elliptical tube bundle design, the average synergy number and heat transfer rate are increased by 22.68% and 35.98% respectively. - Highlights: • FSP (field synergy principle) is used to investigate heat transfer enhancement. • Numerical simulations are performed in circular and elliptical tubes pre-heater. • Numerical results are analyzed using concept of synergy angle and synergy number. • Optimization of elliptical tube bundle by FSP has better performance

  15. 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.

  16. Effects of preheating temperature on cold cracks, microstructures and properties of high power laser hybrid welded 10Ni3CrMoV steel

    International Nuclear Information System (INIS)

    Research highlights: → A Y-groove cold cracking test is designed to assess the laser hybrid welded joints. → As preheating temperature increases, the crack rate decreases and then increases. → Thermal cycles of different preheating temperatures illustrate crack resistance. → The preheating temperature changes the microstructures of laser welded joints. -- Abstract: Laser hybrid welding has become one of the most promising welding methods for high strength low alloy steels due to combining the advantage of the laser and arc. A novel Y-groove cold cracking test adapted to laser hybrid welding is designed to assess the weldability of 10Ni3CrMoV steels at room temperature and different preheating temperatures. The experimental results show that the orientation of the predominant root cracks generally follows the contour of the fusion line. As the temperature increases from 25 oC to 150 oC, at first the root crack rate decreases and then slightly increases at 150 oC. The root crack rate obtained at 120 oC is the lowest. The fracture model changes from a brittle cleavage fracture to a mixture fracture with quasi-cleavage facets and dimples. The thermal cycle curves of laser hybrid welding obtained by temperature measurement systems are used to evaluate the crack resistance and microstructure transformation. The microstructures of welded joints obtained at different temperatures are analyzed by optical microscope (OM). The results reveal that the microstructures of the coarse grained region and the fusion zone at 120 oC have higher cold crack resistance and good impact toughness. Mechanical properties of the welded joint obtained at 120 oC and 150 oC are comprehensively evaluated by microhardness test, uniaxial tensile test and charpy V-notch impact test with side notches. Fractographs of the impact specimens are studied by scanning electron microscopy (SEM). The test results show that the welded joints obtained at 120 oC have satisfactory mechanical properties

  17. Effects of the Structure of Preheating Chamber on Combustion and NOx Emission of a Multi-stage Self-preheating Burner%预热室结构对多段式自预热燃烧器内燃烧及NOx排放特性的影响

    Institute of Scientific and Technical Information of China (English)

    陈冬林; 成珊; 贠英; 邓涛

    2012-01-01

    An introduction is being presented to the structure of a multi-stage self-preheating burner and its four typical preheating chambers. Through CFD simulation, the flow field, flue gas recirculation rate, temperature field, fuel gas burn-out rate and volumetric fraction of NOx in the combustion chamber have been calculated and analyzed in comparison with that of traditional burners. Results show that compared with traditional burners, the proposed burner has a different flow field and a higher adaptability to fuels of low heating values; the structure of its preheating chamber influences both the flue gas recirculation rate and the preheating effectiveness, and therefore accordingly influences the burn-out rate and NOx emission. Furthermore, the load of the burner affects less on the burn-out rate, but more on NOx emission.%提出了一种多段式自预热燃烧器及其4种典型的预热室结构,通过计算流体力学(CFD)方法研究了燃烧室内流场、烟气卷吸率、温度场、燃气燃尽率以及NOx体积分数,并与传统燃烧器的情况进行了对比.结果表明:与传统燃烧器相比,多段式自预热燃烧器改变了燃烧室内流场,对低热值燃料适应性强,其预热室结构同时影响烟气卷吸率和预热效果,并最终影响燃尽率与NOx体积分数;此外,燃烧器负荷对燃尽率影响甚微,但对NOx体积分数影响较大.

  18. Fundamentals of coal depolymerization: investigation of free radicals in coal depolymerization under SRC-II preheater/reactor conditions. Quarterly report, July 1-September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Petrakis, L; Grandy, D W

    1980-09-01

    The overall objective of the project is to study the fundamentals of coal depolymerization under direct liquefaction preheater/reactor conditions. A uniquely designed and fabricated high pressure/high temperature Electron Spin Resonance (ESR) apparatus is used to monitor the formation and behavior of free radicals, which are generally assumed to be the key factor in coal liquefaction. The main conclusions that have been reached are as follows: the methodology indeed allows the observation of the free radical formation and behavior at conditions relating to direct liquefaction preheater/reactor conditions. Measurements can be made continually three minutes after the heating of the coal slurry is started. Temperatures up to 500/sup 0/C and pressures up to 1800 psi are accessible; the observed changes in the concentration of free radicals due to variations of process variables are a real effect. Concentrations can be determined to +- 40%, but process variable manipulation has produced a 12-fold increase; temperature is the single most significant process variable that affects free radical formation; the next most significant effect is due to the combination of solvent and residence time. Some considerable different chemistry takes place especially in the first half-hour of the reaction when the SRC-II distillate is used as the solvent; this effect is particularly pronounced at 460/sup 0/C; and the conversions obtained in the in situ ESR experiments using SRC-II heavy distillate as the solvent are comparable to the shaken autoclave conversion.

  19. 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)

  20. Air Pollution

    OpenAIRE

    Lawther, P. J.

    2014-01-01

    The human costs of air pollution are considerable in Jordan. According to a report published in 2000 by the World Bank under the Mediterranean Environmental Technical Assistance Program (METAP), approximately 600 people die prematurely each year in Jordan because of urban pollution. 50-90% of air pollution in Jordanian towns is caused by road traffic. Readings taken in 2007 by Jordanian researchers showed that levels of black carbon particles in the air were higher in urban areas (caused by v...

  1. Air Pollution.

    Science.gov (United States)

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  2. Investigation of remediation of soil contaminated with diesel fuel using air venting

    International Nuclear Information System (INIS)

    Soil venting is an effective and widely used method to remediate hydrocarbonically contaminated soils. A non-isothermal model, proposed by Lingineni and Dhir (1992) to predict evaporation rates of organic contaminants in an unsaturated non-sorbing soil, was incorporated into a computer code capable of numerically analyzing multi-component diesel fuel. The program accounts for 14 major components of diesel fuel as well as for temperature variation due to evaporation of the contaminant, preheating of the venting air, and heat loss. Experiments to verify the model performance were conducted in a one-dimensional column. Temperature readings from thermocouples located in the test section were recorded during the experiment and the composition of hydrocarbons in the effluent air was also monitored. The effluent gas samples were extracted at the selected times and analyzed with the help of a gas chromatograph. The experimental temperature readings and vapor composition in the extracted samples are in general agreement with the predictions from the computer program. The results show that the diesel components are removed according to their volatility with the higher volatility components being removed first. It is also found that preheating of the venting air can significantly increase the removal rates of the components

  3. The development of air cooled condensation systems

    International Nuclear Information System (INIS)

    EGI - Contracting/Engineering has had experience with the development of air cooled condensing systems since the 1950's. There are two accepted types of dry cooling systems,the direct and the indirect ones. Due to the fact that the indirect system has several advantages over the direct one, EGI's purpose was to develop an economic, reliable and efficient type of indirect cooling system, both for industrial and power station applications. Apart from system development, the main components of dry cooling plant have been developed as well. These are: the water-to-air heat exchangers; the direct contact (DC, or jet) condenser; the cooling water circulating pumps and recovery turbines; and the peak cooling/preheating units. As a result of this broad development work which was connected with intensive market activity, EGI has supplied about 50% of the dry cooling plants employed for large power stations all over the world. This means that today the cumulated capacity of power units using Heller type dry cooling systems supplied and contracted by EGI is over 6000 MW

  4. 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.

  5. Thin air

    OpenAIRE

    Jasanoff, Sheila

    2013-01-01

    Clearing the air How do we grasp the air? Without Michel Callon’s guidance, I might never have asked that question. Years ago, when I first entered environmental law practice, I took it for granted that problems such as air pollution exist “out there” in the real world for science to discover and law to fix. It is a measure of Callon’s influence that I understand the law today as a metaphysical instrument, no less powerful in its capacity to order nature than the tools of the ancient oracular...

  6. Development of a simultaneous Hugoniot and temperature measurement for preheated-metal shock experiments: Melting temperatures of Ta at pressures of 100 GPa

    International Nuclear Information System (INIS)

    Equations of state of metals are important issues in earth science and planetary science. A major limitation of them is the lack of experimental data for determining pressure-volume and temperature of shocked metal simultaneously. By measuring them in a single experiment, a major source of systematic error is eliminated in determining from which shock pressure release pressure originates. Hence, a non-contact fast optical method was developed and demonstrated to simultaneously measure a Hugoniot pressure-volume (PH-VH) point and interfacial temperature TR on the release of Hugoniot pressure (PR) for preheated metals up to 1000 K. Experimental details in our investigation are (i) a Ni-Cr resistance coil field placed around the metal specimen to generate a controllable and stable heating source, (ii) a fiber-optic probe with an optical lens coupling system and optical pyrometer with ns time resolution to carry out non-contact fast optical measurements for determining PH-VH and TR. The shock response of preheated tantalum (Ta) at 773 K was investigated in our work. Measured data for shock velocity versus particle velocity at an initial state of room temperature was in agreement with previous shock compression results, while the measured shock data between 248 and 307 GPa initially heated to 773 K were below the Hugoniot evaluation from its off-Hugoniot states. Obtained interfacial temperatures on release of Hugoniot pressures (100-170 GPa) were in agreement with shock-melting points at initial ambient condition and ab initio calculations of melting curve. It indicates a good consistency for shock melting data of Ta at different initial temperatures. Our combined diagnostics for Hugoniot and temperature provides an important approach for studying EOS and the temperature effect of shocked metals. In particular, our measured melting temperatures of Ta address the current controversy about the difference by more than a factor of 2 between the melting temperatures measured

  7. Air Pollution

    Science.gov (United States)

    ... to a close in June 2013 when the company, Conscious Clothing, was awarded the My Air grand ... Page Options: Request Translation Services Facebook Twitter LinkedIn Google+ Reddit Email Evernote More Increase Font Size Decrease ...

  8. Performance study of an induced air porous radiant burner for household applications at high altitude

    International Nuclear Information System (INIS)

    Porous radiant burners are presented as an alternative technology for improving the thermal efficiency of conventional burners. A performance study of an induced air porous radiant burner (IAPRB) with submerged combustion using natural gas was performed at high altitude to assess the feasibility of employing a porous burner operated with induced air in household applications. The experiments were performed in two-layer porous media. The preheating and combustion zones consisted of 400 ppi alumina honeycomb and 90% porosity silicon carbide foam, respectively. Three power per unit area levels, 370 kW/m2, 480 kW/m2 and 670 kW/m2, were evaluated. Pollutant emissions (CO and NOx), the radiation efficiency, the temperature profile along the bed, the primary air rate and the pressure drop across the porous materials were measured. A maximum burner thermal efficiency near 50% was obtained for 370 kW/m2, with a radiation efficiency of 27%. The preheating of the premix caused an increased bed pressure drop, which resulted in a reduction in ambient air entrainment and an air deficiency in the reaction zone. The CO emissions exceeded the standard allowable emissions. - Highlights: • A performance study of an induced air porous radiant burner was carried out. • Thermal and radiation efficiencies were measured for a porous radiant burner. • CO and NOx emission levels were measured for a porous radiant burner. • A maximum porous burner thermal efficiency near 50% was obtained for 370 kW/m2

  9. The effect of pre-heating and pre-irradiation with gamma rays on thermal annealing in bis [n-benzoil-n-phenyl hydroxilaminate] copper (II)

    International Nuclear Information System (INIS)

    The main purpose of this work was to make a contribution to the study of the chemical effects of the (n,γ) reaction on copper chelate. The influence of some factors such as pre-heating and pre-irradiation with gamma-rays on the retention and thermal annealing of bis-[N-benzoil-N-phenlhydroxilaminate] copper (II) was investigated. The complex was synthesized and later characterized by means of: determination of the melting-Point, elemental analysis, infra-red and vesible range absortion spectrophotometry. The compound was heated and also irradiated with gamma-rays in order to verify the effect of thermolysis and radiolysis on the retention. It seems that heat gamma-radiation can produce deffects which will lower the susceptibility of the compound to thermal annealing. On the model envolving electronic species some explanation of ours results were made and a mechanism was proposed for the retention and thermal annealing aasuming the capture of free electrons and also the existence of holes. (author)

  10. Dependence of the fast waves-plasma interactions in pre-heated spherical tokamaks on the antenna location and poloidal extension

    International Nuclear Information System (INIS)

    Full Text:In the magnetically confined fusion devices, externally launched e.m. waves are used, e.g., for heating, non-inductive current drive and turbulent transport suppression barriers. In view of the complexity of these processes, it is desirable to assist the planning of the actual experiments by reliable theoretical (computational) studies. This work aims to (i) assess the effect of antenna position and extension on the fast waves-plasma interactions in pre-heated spherical tokamaks and consequently, (ii) to further the physical understanding as well as to determine optimal conditions in order to achieve the imposed goals. Thus, using as a study case the spherical tokamak START, we considered the following antenna positions and extensions: (a) low field side location and iT±π/4 poloidal extension; (b) above and below middle-plane locations (two separate sections) and extending (each) π/2; (c) (hypothetical) circular, 2π-extension. We solved the full wave equations in order to consistently determine the global e.m. field for Alfvinic modes in inhomogeneous, non-uniformly magnetized, resistive, small aspect ratio tokamak plasma in the presence of externally launched fast waves. The global approach consists of simultaneous treatment of the plasma-vacuum-external RF source-vacuum-metal wall configuration with the appropriate consideration of wave propagation, transmission, absorption and mode conversion; in this, no simplifying approximations or small parameter extension are used. Illustrative results of these investigations will be presented and discussed

  11. Thermochemical treatment of E-waste from small household appliances using highly pre-heated nitrogen-thermogravimetric investigation and pyrolysis kinetics

    International Nuclear Information System (INIS)

    The EU directive on waste of electrical and electronic equipment (WEEE) 2002/96/EC has set a goal of recovering 70-80% in terms of materials and energy. Nowadays, thermal cracking (pyrolysis) of such waste streams is receiving renewed attention, due to the energy and material recovery that can be achieved and therefore the sustainable waste management. However, it still lacks the kinetic background which is of great importance for a successful design of thermochemical processes. In this study the kinetic parameters of WEEE (originating from small household appliances) pyrolysis using highly pre-heated nitrogen under six different heating rates (1-2.5 K/s) have been estimated using a combination of model-free and model fitted methods. Even though WEEE is heterogeneous material, similar behavior at each of the six different heating rates applied was observed. The activation energy of the pyrolysis process determined with two different model-free methods gave comparable results. Pre-exponential factor and reaction order were determined using the Coats-Redfern method. The estimated kinetic parameters for the WEEE pyrolysis are: E = 95.54 kJ/mol, A = 1.06 x 108 and n = 3.38.

  12. The combined toroidicity, ellipticity and triangularity effects on the energy deposition of Alfven modes in pre-heated, low aspect ratio tokamaks

    International Nuclear Information System (INIS)

    The combined plasma non-uniformity effects on the energy deposition of Alfven waves launched by an external antenna in pre-heated spherical tokamaks are investigated. The following relevant physical processes are here possible: (a) the emergence of gaps in the shear Alfven continuum spectrum and the generation of discrete global Alfven eigenmodes with frequencies inside the gaps; (b) multi-wave interactions, interactions of gaps of the same kind (e.g., toroidicity induced) and of different kinds (toroidicity, ellipticity and triangularity induced) as well as of secondary order gaps arising when a pair of modes is coupled to one or more modes through other coupling parameters; (c) basic wave-plasma interactions as propagation, reflection, mode-conversion, tunneling and deposition. Thus, we solved numerically the full 2D wave equations for the vector and scalar potentials, using a quite general two-fluid resistive tensor-operator, without any geometrical limitations. The results obtained indicate the existence of antenna-launched wave characteristics for which the power is most efficiently coupled in outer regions of plasmas, which is of special interest for low aspect ratio tokamaks, e.g., for the generation of non-inductive current drive as well as for turbulence suppression and transport barriers formation

  13. Research and application of accelerated intercommunication method in SAGD cyclic pre-heating period%SAGD 循环预热阶段加速连通方法的研究及应用

    Institute of Scientific and Technical Information of China (English)

    赵睿; 杨智; 吴永彬; 张瑞强; 罗池辉; 郤一臻

    2015-01-01

    SAGD 循环预热阶段的预热效率和连通速度,都对生产阶段的生产效果具有重要影响。通过数值模拟研究,提出一种加快 SAGD 循环预热阶段连通速度的方法,建立了“低压—高压—拟 SAGD”的预热模式,实现了在较短时间、形成优先渗流通道风险较低的情况下,注采井之间的水力连通速度得以有效提高的目的。该方法在风城超稠油油藏 SAGD 规模开发中的应用效果良好,具有一定的推广价值。%The pre-heating efficiency and communicating speed in SAGD cyclic preheating period have important effects on production during production period. Through numerical simulation research, a method of accelerating intercommunication speed in SAGD cyclic preheating period was presented, and a preheating mode of ‘low pressure-high pressure-simulated SAGD’was built, which has effectively improved the hydraulic communication speed between injectors and producers while ensuring low risk in establishing preferred seepage passages in a short time. This method was effectively used in SAGD development of Fengcheng Ultra-heavy Oil Reservoir and is of certain promotion value.

  14. 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).

  15. Healthy Air Outdoors

    Science.gov (United States)

    ... lung.org > Our Initiatives > Healthy Air > Outdoor Healthy Air Outdoors The quality of the air we breathe ... families and can even shorten their lives. Outdoor Air Pollution and Health Outdoor air pollution continues to ...

  16. Air quality

    International Nuclear Information System (INIS)

    This chapter of the 'Assessment of the state of the environment in Lebanon' describes the air quality and identifies the most important air quality issues. Baseline information about the factors affecting dispersion and the climate of Lebanon presents as well and overall estimation of total emissions in Lebanon. Emissions from vehicles, electricity and power plants generation are described. Industrial emitters of air pollutants are described for each kind of industry i.e.cement plants, Selaata fertilizer factory, sugar-beet factory, refineries and for those derived from the use of leaded fuel . Impact of economic and human activities on air quality in Lebanon (especially in Beirut and Tripoli) are quantified by quantities of CO2, SO2, NOx, total suspended particulates(TSP), deposition and their environmental effects on health. In abscence of emissions monitoring, data available are expressed in terms of fuel use, output and appropriate empirical factors, national output and workfores sizes. Finally key issues and some potential mitigation /management approaches are presented

  17. Welding Procedure of Preheater for Boiler Feed Water%锅炉供水预热器的焊接工艺

    Institute of Scientific and Technical Information of China (English)

    黄向红

    2011-01-01

    根据锅炉供水预热器的结构特点对其母材焊接性进行分析,特别是对筒体(20R)与膨胀节(0Cr18Ni9)以及换热管(00Cr17Ni14Mo2)与管板(16MnR)的异种金属焊接性进行了详细分析,制定了具体的焊接工艺.焊后用5~10倍的放大镜检查,焊缝无裂纹、表面气孔、缩孔未熔合等缺陷;进行无损检验及水压试验,均符合标准要求.经实际生产验证,该技术方案切实可行,焊接质量良好,且设备投入使用后运行正常.%According to structure characteristics of preheater for boiler feed water ,the weldability of base material was analyzed especially for the weldability of dissimilar metal,such as the barrel (20R)and expansion joints ( OCr18Ni9,as well as the heat pipe (00Crl7Nil4Mo2)and tube plate( 16MnR) ,then the specifie welding procedure was established.Using 5~10 times magnifier to check erack, gas pocket in surface , incomplete fusion and other defects, and non-destructive and hydraulic tests were perfomed,the results all met standard quirements. The actual production proved that this technology approach is good and feasible, the welding quality is perfect,and the equipment runs properly.

  18. 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 of...

  19. Air pollution

    International Nuclear Information System (INIS)

    Australian cites experience a number of current and emerging air pollution problems. Concentrations of traditional primary pollutants such as CO, lead and dust have fallen in recent years as a consequence of air pollutant control measures, and the widespread introduction of lead-free petrol. However, recommended guidelines for ozone, the principal component of photochemical smog, are regularly exceeded in major capital cities in the summer months. In addition, it is predicted that extensive urban expansion will lead to much greater dependence on the motor vehicle as the primary means of transportation. Effects of air pollution are felt at a variety of scales. Traditionally, concerns about gaseous and particulate emissions from industrial and vehicular sources were focused on local impacts due to exposure to toxic species such as CO and lead. As noted above, concentrations of these pollutants have been reduced by a variety of control measures. Pollutants which have effects at a regional scale, such as photochemically-produced ozone, and acidic gases and particles have proved more difficult to reduce. In general, these pollutants arc not the result of direct emissions to atmosphere, but result from complex secondary processes driven by photochemical reactions of species such as NO2 and aldehydes. In addition, global effects of gaseous and particulate emissions to the atmosphere have received significant recent attention, concentrations of atmospheric CO2 with predicted impacts on global climate, and ozone depletion due to anthropogenic emissions of chlorine-containing chemicals are the two major examples. Combustion processes from petrol- and diesel-fuelled vehicles, make major contributions to air pollution, and the magnitude of this contribution is discussed in this article

  20. Clean Hydrogen Production via Novel Steam-Air Gasification of Biomass

    International Nuclear Information System (INIS)

    Gasification converts biomass into H2 and CO rich product gas by using air, oxygen and/or steam as reaction agent. An experimental and modelling study of hydrogen production was conducted using a laboratory scale counter-current fixed bed gasifier with preheated air and steam as the gasifying agents. Commercial charcoal was used as the fuel and the reactor bed was maintained at temperatures of 750-960 C by external heaters. H2 (17-28 vol%), CO (5-11 vol%) and CO2 (18-21 vol%) forms a large portion of the synthesis gas produced depending on the ratio of the gasifying agent. The experimental work was coupled with both equilibrium and kinetic modelling to predict the equilibrium composition, conversion rates and temperature profile. (authors)

  1. 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.

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. Hazardous Air Pollutants

    Science.gov (United States)

    ... Facebook Twitter Google+ Pinterest Contact Us Hazardous Air Pollutants Hazardous air pollutants are those known to cause ... protect against adverse environmental effects. About Hazardous Air Pollutants What are hazardous air pollutants? Health and Environmental ...

  7. Impact of Pulverized Coal Preheating on Coal Combustion Behavior in Pulverized Coal Injection of Blast Furnace%煤粉预热对高炉喷吹中煤粉燃烧行为的影响

    Institute of Scientific and Technical Information of China (English)

    赵俊东; 王恒; 杨永昌; 杜辉杰; 宋广懂

    2011-01-01

    通过建立数学模型,在Fluent软件的基础上结合自编程序,对不同预热温度下高炉喷吹煤粉的燃烧进行了模拟,得到了预热温度对煤粉燃烧的影响规律模型中包含了煤粉与O2,CO2及水蒸汽的异相反应,且考虑了焦炭的燃烧反应确定了同旋区的大小与形状,将煤粉燃烧空间划分为4个区域,对不同区域分别提出不同假设进行处理计算结果表明,煤粉预热后进行喷吹可促进煤粉在风口前提前气化,使煤粉的燃烧区域前移,提高了煤粉在回旋区的燃尽率:预热温度每提高50℃,煤粉在回旋区的燃尽率平均提高2%.%By establishing the mathematical model and using own program based on Fluent software, the combustion of pulverized coal injected at different preheated temperatures was simulated, and the impact of different preheated temperatures on coal burning was examined. The model contained the heterogeneous reactions of coal with oxygen, carbon dioxide and steam, and the burning reaction of coke was also considered. The size and shape of raceway were determined, and the coal combustion space was divided into four zones which were treated with different assumptions respectively. The computational results show that when preheated pulverized coal is used in pulverized coal injection, the coal gasification is promoted in advance, the combustion region is moved forward, and the burnout rate of coal in the raceway is improved. When coal preheated temperature is increased 50 ℃, the coal burnout rate is raised 2% on average.

  8. Pressurized air supply device

    International Nuclear Information System (INIS)

    Ventilation air-conditioning facilities in a nuclear reactor building are adapted to suck clean external air not containing radioactivity through air supply filters disposed at an air intake port of the nuclear reactor building by means of an air supply blower and then supply the sucked air through an air supply duct and an air supply port to the inside of the power plant. Futher, pipeways for supplying sucked air to a compressor is branched from the air supply duct, through which air is supplied to an air compressor for instrumentation and an air compressor used in the power plant. The air sucked and compressed in the air compressor for instrumentation is further supplied by way of pipeways for supplying air for instrumentation to air-actuated valves, instruments, etc. Further, air sucked and compressed in the air compressor used in the power plant is further supplied by way of air supply pipeways for the power plant to a reservoir, air mask, etc. By supplying clean compressed air in this way, operators exposure dose can be reduced. (T.M.)

  9. 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 and...

  10. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    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...... 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....

  11. 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.

  12. A combined cycle plant with air and fuel recuperator for captive power application, Part 1: Performance analysis and comparison with non-recuperated and gas turbine cycle with only air recuperator

    International Nuclear Information System (INIS)

    Highlights: • A combined gas–steam cycle for captive application is proposed and analyzed. • The cycle uses gas turbine exhaust heat for subsequent air and fuel preheating. • Further heat recuperation takes place for steam generation in the HRSG. • Effect of pressure ratio and steam injection to combustor on performance is studied. • Comparison with non-recuperated and cycle with only air recuperator is provided. - Abstract: In this paper, a simulation based performance of a recuperated combined gas turbine (GT) and steam turbine (ST) cycle is presented. The proposed combined cycle (CC) utilizes GT exhaust heat for air and fuel preheating sequentially one after the other. Comparison of performance of the recuperated CC is made with a non-recuperated CC and a CC with only the air recuperator (AR). At a compressor pressure ratio (CPR) of 12, the CC with both AR and fuel recuperator (FR) shows 16.8% and 54.44% gain in performance over the cycle with only the AR and no recuperators. A parametric study based on variation of CPR and steam injection rate (STIR) indicate improvement in efficiency and power with increase in CPR and STIR both. With CPR, the net GT power increases, however the net ST power shows a decreasing trend particularly for the cycle without recuperators. With STIR, the net GT power increases and the bottoming ST power although decreases but with less significance. The net ST power of the CC plant without recuperators is significantly less for the bottoming ST cycle to be economically feasible. The CC plant shows an average 53.32% gain in efficiency and power over the plant without the bottoming ST cycle

  13. Air protection. Ochrana ovzdusia

    Energy Technology Data Exchange (ETDEWEB)

    Siska, F.

    1980-01-01

    This paper discusses problems of air pollution control, air pollution abatement and effects of air pollution. Air pollution caused by black and brown coal combustion, by fossil-fuel power plants and by coking plants is evaluated. Air pollution by dusts, sulfur oxides, nitrogen oxides, carbon monoxide, ammonia as well arsenic, barium, beryllium, boron, chromium, gallium, cobalt, manganese, copper, nickel, lead, plutonium, titanium and vanadium, which sometimes accompany ashes in coal, is analyzed. Methods of air pollution abatement such as fluidized bed combustion, coal preparation, desulfurization or dry coke quenching are described. Systems for air pollution control are presented: air filtration, cyclones, electrostatic precipitators. Systems of air pollution measurement and recording are evaluated. Propagation of air pollutants in the atmosphere as well as the factors which influence pollutant propagation are characterized. Problems associated with site selection for fossil-fuel power plants are also discussed. An analysis of economic aspects of air pollution abatement and air pollution control is made. (55 refs.)

  14. Indoor Air Quality

    Science.gov (United States)

    ... protect yourself and your family. Learn more Air Quality at Work Workers should breathe easy while on the job, but worksites with poor air quality put employees at risk. Healthy air is essential ...

  15. 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 ...

  16. Bad Air Day

    Science.gov (United States)

    ... link, please review our exit disclaimer . Subscribe Bad Air Day Air Quality and Your Health In many parts of the country, summer has the worst air quality of any season. When the forecast says ...

  17. Air quality in barns for milk-fed calves

    International Nuclear Information System (INIS)

    Seventy per cent of the veal produced in Canada comes from Quebec. This paper reported on the air quality in barns used for milk-fed calves. It is known that air quality inside livestock buildings has an impact on both workers and animals, particularly in winter when air circulation is reduced. In this study, air quality inside barns was studied during the winter, spring and summer. Three types of barns with 3 different types of ventilation typically found in Quebec were evaluated. These included those with preheated corridors, lateral air entries, and central chimneys. Gases were measured in order to determine concentrations and emissions of: ammonia (NH3) which is toxic, colourless and flammable; hydrogen sulfide (H2S) which is very toxic, flammable; carbon dioxide (CO2) which is colourless and odourless; nitrous oxide (N2O) which is colourless and flammable, but harmless to health in the short-term; carbon monoxide (CO) which is colourless, odourless and flammable; and methane (CH4) which is the principal constituent released by animals, and is also colourless, odourless and extremely flammable. When exposed to air, both methane and carbon monoxide can produce an explosive mix especially in an enclosed area. Bacteria, mold, endotoxins, and dust are also present in barns. Samples of gases were analyzed with the help of different portable apparatuses. Results revealed that there are no significant problems with air quality in barns used for milk-fed calves in Quebec. It was determined that the inside temperature was appropriate even during summer periods, and although the relative humidity was higher than the recommended values for the care and handling of farm animals, it was still acceptable. In winter, ammonia was the only gas present in concentrations that reached values of weighted average exposure. Also, concentrations of bacteria were higher during winter. It was suggested that better air ventilation during the winter period would lower ammonia and bacteria

  18. U型钢管空气预热器在CFB垃圾焚烧锅炉中的应用%The Application of U Type Pipe Air Preheater in CFB Municipal Solid Waste Boiler

    Institute of Scientific and Technical Information of China (English)

    刘强

    2012-01-01

    介绍一种布置于过热器之前的U型钢管空气预热器结构.这种结构在CFB纯烧垃圾锅炉中应用,可以提高一次风的温度,减少进风热损失,稳定炉膛的燃烧工况,实现锅炉高效节能运行.

  19. 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…

  20. 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.

  1. Indoor Air Pollution (Environmental Health Student Portal)

    Science.gov (United States)

    ... Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ... Pollution Indoor Air Pollution Print this Page Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ...

  2. 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

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

    International Nuclear Information System (INIS)

    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

  4. QUALITY ENHANCEMENT OF PRODUCER GAS FROM CASSAVA RHIZOME USING HIGH TEMPERATURE AIR-STEAM DOWNDRAFT GASIFICATION

    Directory of Open Access Journals (Sweden)

    Worapot Ngamchompoo

    2013-01-01

    Full Text Available High Temperature Air-Steam Gasification (HTAG was performed on a bench-scale downdraft gasifier. A cassava rhizome was used as feedstock for the gasification. Air and steam were utilized as the gasifying agents. The objectives in this study were to study the potential of HTAG technology applied with a downdraft gasifier to improve producer gas quality in terms of Higher Heating Value (HHV and lower tar content. The results were compared with conventional air-steam gasification (without preheating. The results were that the HHV of the producer gas from the HTAG process at 900°C improved by as much as 5.1 MJ/Nm3 (at S/B ratio = 0.3, while the air-steam gasification, HTAG at 300°C and HTAG at 600°C couldonly obtain a HHV of 3.8 MJ/Nm3 (at S/B = 0.4, 4.2 MJ/Nm3 (at S/B = 0.1 and4.8 MJ/Nm3 (at S/B = 0.2, respectively. In addition, tar content in the producer gas of the HTAG process at 900°C had the lowest value (95 mg/m3 which could be used as fuel in an internal combustion engine. While the minimum tar content of the air-steam gasification was 320 mg/m3. In the HTAG process at 900°C, the maximum Cold Gas Efficiency (CGE was 65%, which was slightly lower than the CGE of air-steam gasification (69%. However, in the HTAG process at 300, 600 and 900°C the maximum Hot Gas Efficiency (HGE increased 33% (from 72 to 96%, 25 (from 72 to 90% and 7 (from 72 to 77%, respectively; when compared with air-steam gasification.

  5. Indoor Air Quality

    OpenAIRE

    Korlakunta Divya #1, M.Anil Kumar

    2013-01-01

    The main aim of our project is to maintain the indoor air quality.The analysis is done on different parameters like temperature,relativehumidity,CO2,lights,sens ors and air conditioners to maintain the indoor environment.This report provides overview on importance of indoor air quality in an office or any other closed structure. It also discusses about the effects of poor indoor air quality, the various factors that affect the indoor air quality and various methods to assess indoor air qualit...

  6. 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...

  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. 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...

  9. Nuclear air cleaning

    International Nuclear Information System (INIS)

    This report briefly describes the history of the use of high- efficiency particulate air filters for air cleaning at nuclear installations in the United States and discusses future uses of such filters

  10. 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...

  11. Performance evaluation of a state-of-the-art solar air-heating system with auxiliary heat pump. Final report, 1 October 1978-30 September 1979

    Energy Technology Data Exchange (ETDEWEB)

    Karaki, S.; Brisbane, T.E.; Waterbury, S.S.; Lantz, T.G.

    1980-01-01

    The solar heating system in Solar House II, evaluated during the heating season of 1978-1979, consists of 57.9 m/sup 2/ of Solaron Series 3000 Collectors, 10.3 m/sup 3/ of pebble bed storage, domestic water preheating capability and a Carrier air-to-air heat pump as an auxiliary heater. Although the control subsystem was specially constructed to facilitate experimental changes and data reduction, the balance of the solar system was assembled with off-the-shelf components. Descriptions of the building and the system, modes of system operation, the data acquisition system, data processing, and performance - thermal, collector, storage, and heat pump - are included. (MHR)

  12. Indoor air: Reference bibliography

    International Nuclear Information System (INIS)

    The U. S. Environmental Protection Agency initially established the indoor air Reference Bibliography in 1987 as an appendix to the Indoor Air Quality Implementation Plan. The document was submitted to Congress as required under Title IV--Radon Gas and Indoor Air Quality Research of the Superfund Amendments and Reauthorization Act of 1986. The Reference Bibliography is an extensive bibliography of reference materials on indoor air pollution. The Bibliography contains over 4500 citations and continues to increase as new articles appear

  13. Indoor Air Quality Manual.

    Science.gov (United States)

    Baldwin Union Free School District, NY.

    This manual identifies ways to improve a school's indoor air quality (IAQ) and discusses practical actions that can be carried out by school staff in managing air quality. The manual includes discussions of the many sources contributing to school indoor air pollution and the preventive planning for each including renovation and repair work,…

  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. 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...

  16. 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 ... is known as sick building syndrome. Usually indoor air quality problems only cause discomfort. Most people feel ...

  17. Air Travel Health Tips

    Science.gov (United States)

    MENU Return to Web version Air Travel Health Tips Air Travel Health Tips How can I improve plane travel? Most people don't have any problems when ... and dosages of all of your medicines. The air in airplanes is dry, so drink nonalcoholic, decaffeinated ...

  18. 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.

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

    International Nuclear Information System (INIS)

    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.

  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. 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....

  2. Released air during vapor and air cavitation

    Science.gov (United States)

    Jablonská, Jana; Kozubková, Milada

    2016-06-01

    Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ɛ model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

  3. 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....

  4. Health Effects of Air Pollution

    Science.gov (United States)

    ... air pollution How to protect yourself from air pollution Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home The environment and your health Air Health effects of air pollution ... Health effects of air pollution Breathing air that ...

  5. 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.

  6. Structure of reaction zone of normal temperature air flameless combustion in a 2 ton/h coal-fired boiler furnace

    Energy Technology Data Exchange (ETDEWEB)

    Xing, X.; Wang, B.; Lin, Q. [University of Science & Technology of China, Hefei (China)

    2007-06-15

    By injecting normal temperature air into a coal-fired boiler furnace at an evaporation capacity of 2 ton/h, flameless combustion with little noise is achieved. Numerical simulations and experimental research shows that the combustion takes place in a wide and broad area, almost the whole furnace, resulting in a voluminal reaction. For this normal temperature air flameless combustion (NTAFC), when the excess air coefficient approaches 1, the fuel combusts fully. The concentrations of NOx and CO in flue gas are relatively low and are hardly affected by either an excess air coefficient or thermal load. In front of the jet is a low-temperature gas-mixing zone whose diameter is equivalent to that of the jet, and the temperature of this zone increases with the distance from the jet tip. A mild stable combustion reaction without a visible flame takes place in the part of the furnace where the temperature value is higher and the amplitude of variation is not large. In addition to the advantages shared with high-temperature air combustion (e.g. uniform temperature distribution, low NOx and CO emission, high combustion efficiency, and so on), NTAFC does not require a high-temperature air-preheating system and is easier to actualize.

  7. Air Quality in Lithuania

    Energy Technology Data Exchange (ETDEWEB)

    Pietilae, P. [Tampere University of Technology / ECAT-Lithuania (Lithuania); Kliucininkas, L. [Department for Environmental Engineering, Kaunas University of Technology (Lithuania)

    2000-07-01

    Sustainable monitoring of the ambient air is the major preventive measure of ensuring its proper quality. Only with a monitoring procedure going-on a continuous basis it is possible to make an objective evaluation of air pollution trends, of the efficiency of air protection measures and, partially, to a certain extent of the impact the pollution exerts on a human health. The information stemming from the monitoring procedure must be reliable, sustainable and efficient. (orig.)

  8. Indonesia's Clean Air Program

    OpenAIRE

    Budy P. Resosudarmo

    2002-01-01

    Unprecedented industrial development in Indonesia during the last two decades, accompanied by a growing population, has increased the amount of environmental damage. One of the most important environmental problems is that the level of air pollution in several large cities has become alarming, particularly in the last few years. This high pollution level has stimulated the government to develop a national clean air program designed to control the quantity of pollutants in the air. However, th...

  9. Bad traffic, bad air

    OpenAIRE

    Duca, Edward

    2012-01-01

    Air pollution is one of Malta’s greatest concerns. Transportation is the principal source with over 300,000 vehicles belching out smoke, which damages our environment and health. Emissions from vehicles need to be monitored and controlled, and the information used to improve the current system and ensure an acceptable air quality. By using the pollution data set, Nicolette Formosa (supervised by Dr Kenneth Scerri) mapped the air pollution levels and major sources around Malta. http://www....

  10. Emergency air supply

    International Nuclear Information System (INIS)

    An air supply safety device is described which can operate in an hostile environment. The system ensures that should the ring mains supply or the operator's individual hose fail an emergency air supply is obtained from a compressed air bottle fed to the operator's face mask via a valve. The valve switches from mains/mask to emergency supply/mask when the mains pressure falls below the emergency supply pressure. (U.K.)

  11. Radioactive material air transportation

    International Nuclear Information System (INIS)

    As function of the high aggregated value, safety regulations and the useful life time, the air transportation has been used more regularly because is fast, reliable, and by giving great security to the cargo. Based on the International Atomic Energy Agency (IAEA), the IATA (International Air Transportation Association) has reproduced in his dangerous goods manual (Dangerous Goods Regulations - DGR IATA), the regulation for the radioactive material air transportation. Those documents support this presentation

  12. Electric air filtration movie

    International Nuclear Information System (INIS)

    The use of electrostatics to improve the performance of conventional air filters has gained considerable attention in recent years. This interest is due to the higher efficiency and reduced pressure drop of electrically enhanced filters compared to conventional fibrous filters. This 30-minute movie presents a state of the art review of electric air filters in the United States with major illustrations provided by the research and development program at the Lawrence Livermore National Laboratory sponsored by the Department of Energy. The electric air filters described in this movie are mechanical air filters to which electrical forces have been added

  13. Applications Using AIRS Data

    Science.gov (United States)

    Ray, S. E.; Pagano, T. S.; Fetzer, E. J.; Lambrigtsen, B.; Olsen, E. T.; Teixeira, J.; Licata, S. J.; Hall, J. R.; Thompson, C. K.

    2015-12-01

    The Atmospheric Infrared Sounder (AIRS) on NASA's Aqua spacecraft has been returning daily global observations of Earth's atmospheric constituents and properties since 2002. With a 12-year data record and daily, global observations in near real-time, AIRS data can play a role in applications that fall under many of the NASA Applied Sciences focus areas. For vector-borne disease, research is underway using AIRS near surface retrievals to assess outbreak risk, mosquito incubation periods and epidemic potential for dengue fever, malaria, and West Nile virus. For drought applications, AIRS temperature and humidity data are being used in the development of new drought indicators and improvement in the understanding of drought development. For volcanic hazards, new algorithms using AIRS data are in development to improve the reporting of sulfur dioxide concentration, the burden and height of volcanic ash and dust, all of which pose a safety threat to aircraft. In addition, anomaly maps of many of AIRS standard products are being produced to help highlight "hot spots" and illustrate trends. To distribute it's applications imagery, AIRS is leveraging existing NASA data frameworks and organizations to facilitate archiving, distribution and participation in the BEDI. This poster will communicate the status of the applications effort for the AIRS Project and provide examples of new maps designed to best communicate the AIRS data.

  14. Air pollution meteorology

    International Nuclear Information System (INIS)

    This report is intended as a training cum reference document for scientists posted at the Environmental Laboratories at the Nuclear Power Station Sites and other sites of the Department of Atomic Energy with installations emitting air pollutants, radioactive or otherwise. Since a manual already exists for the computation of doses from radioactive air pollutants, a general approach is take here i.e. air pollutants in general are considered. The first chapter presents a brief introduction to the need and scope of air pollution dispersion modelling. The second chapter is a very important chapter discussing the aspects of meteorology relevant to air pollution and dispersion modelling. This chapter is important because without this information one really does not understand the phenomena affecting dispersion, the scope and applicability of various models or their limitations under various weather and site conditions. The third chapter discusses the air pollution models in detail. These models are applicable to distances of a few tens of kilometres. The fourth chapter discusses the various aspects of meteorological measurements relevant to air pollution. The chapters are followed by two appendices. Apendix A discusses the reliability of air pollution estimates. Apendix B gives some practical examples relevant to general air pollution. It is hoped that the document will prove very useful to the users. (author)

  15. Restoran Buenos Aires = Restaurant Buenos Aires

    Index Scriptorium Estoniae

    2008-01-01

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

  16. Air pollution and society

    OpenAIRE

    Brimblecombe P.

    2010-01-01

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

  17. AIR RADIOACTIVITY MONITOR

    Science.gov (United States)

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

    1961-04-11

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

  18. Air Pollution, Teachers' Edition.

    Science.gov (United States)

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

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

  19. Air Pollution and Industry.

    Science.gov (United States)

    Ross, R. D., Ed.

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

  20. Transportation and air quality

    International Nuclear Information System (INIS)

    In the greater Vancouver regional district (GVRD), some 80% of the annual production of 600,000 tonnes of air pollutants come from motor vehicles. Three critical air quality issues in the GVRD are discussed: local air pollution, ozone layer depletion, and greenhouse gas emissions, all of which are fundamentally linked to transportation. Overall air quality in the GVRD has been judged acceptable by current federal standards, but ground-level ozone has exceeded maximum tolerable levels at some locations and concentrations of suspended particulates are above maximum acceptable levels. Serious deterioration in air quality has been predicted unless a concerted effort is made to manage air quality on an airshed-wide basis. The GVRD is developing Canada's first Air Management Plan with the goal of halving atmospheric emissions by 2000. GVRD transportation priorities stress public transit, walking, cycling, car pooling, and reducing of travel demand; however, the viability of such strategies depends on decisions made outside the transportation sector. Restricted authority and jurisdiction also hinder GVRD goals; the regional level of government has no authority over highways or transit and only has authority for pollution control in some parts of the Fraser Valley. Airshed quality management, using the Los Angeles example, is seen as a possible direction for future GVRD policymaking in the transportation sector. A single regional planning agency with responsibility for transportation, land use, and air quality management appears as the best option for an integrated approach to solve multiple problems. 19 refs

  1. International Air Services

    OpenAIRE

    Productivity Commission

    2001-01-01

    On 12 December 1997 the Treasurer referred international air services arrangements to the Industry Commission for inquiry and report within nine months. The Commission was asked to report on the arrangements for negotiating entitlements under air services agreements and the process of allocating capacity entitlements to Australian carriers.

  2. Energy and air quality

    International Nuclear Information System (INIS)

    This is one of a series of handbooks designed to provide nontechnical readers with a general understanding of the interaction between energy development and environmental media and to provide a rudimentary data base from which estimates of potential future impacts can be made. This handbook describes the air quality impacts of energy development and summarizes the major federal legislation which regulates the potential air quality impacts of energy facilities and can thus influence the locations and timing of energy development. In addition, this report describes and presents the data which can be used as the basis for measurement, and in some cases, prediction of the potential conflicts between energy development and achieving and maintaining clean air. Energy utilization is the largest emission source of man-made air pollutants. Choices in energy resource development and utilization generate varying emissions or discharges into the atmosphere, the emissions are affected by the assimilative character of the atmosphere, and the resultant air pollutant concentrations have biological and aesthetic effects. This handbook describes the interrelationships of energy-related air emissions under various methods of pollution control, the assimilative character of the air medium, and the effects of air pollution. The media book is divided into three major sections: topics of concern relating to the media and energy development, descriptions of how to use available data to quantify and examine energy/environmental impacts, and the data

  3. Air Pollution Primer.

    Science.gov (United States)

    National Tuberculosis and Respiratory Disease Association, New York, NY.

    As the dangers of polluted air to the health and welfare of all individuals became increasingly evident and as the complexity of the causes made responsibility for solutions even more difficult to fix, the National Tuberculosis and Respiratory Disease Association felt obligated to give greater emphasis to its clean air program. To this end they…

  4. Over the air test

    DEFF Research Database (Denmark)

    2015-01-01

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

  5. Air pollution and air cleaning equipment in buildings

    OpenAIRE

    Evdokimova, Ekaterina

    2011-01-01

    The subject of this thesis work is air pollution and air cleaners in building. Clean air has big significance for human health because different pollutions can cause allergy and disease. The quality of indoor air affects health and effective working. The aim of this thesis is to present methods and devices for cleaning the air.

  6. AIRE-Linux

    Science.gov (United States)

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

    2015-08-01

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

  7. 纤维预热温度对3D-Cf/Al复合材料显微组织及力学性能的影响%Effect of fiber preheating temperature on microstructure and mechanical properties of 3D-Cf/Alcomposites

    Institute of Scientific and Technical Information of China (English)

    聂明明; 徐志锋; 徐鹏; 余欢; 王振军

    2016-01-01

    The vacuum gas pressure infiltration was performedtopreparethe 3D-Cf/Al composite reinforced 3D five-directional braided performs woven by M40 graphite fiber with thefibervolume fraction of 51%. The effects of preheating temperature on the microstructure and tensile strength of 3D-Cf/Al composites were studied,and the difference between 3D-Cf/Al composites and continuous Cf/Al compositeswerecompared.The results show that the density of composite increaseswith the fiber preheat temperatureincreasing,the increase ofthe fiber preheat temperature can effectively reduce the infiltration defects,such asinternal holes and partial fiber reunited.The tensile strength reduces significantly with the fiber preform preheating temperature increasing.Moreover, the density,tensile strength and elasticity modulus of the 3D-Cf/Al compositesare97.3%,777.8 MPa and 186.1GPa, respectively,when the preheating temperature, infiltration temperature, impregnation pressure and dwell time of the fiber are 500℃, 720℃, 7 MPa and 20 min.%采用真空气压浸渗法制备纤维体积分数为51%的三维五向编织M40碳纤维增强铝基复合材料(3D-Cf/Al),研究纤维预热温度对3D-Cf/Al 复合材料显微组织与力学性能的影响,并对比研究3D-Cf/Al 复合材料与单向连续Cf/Al 复合材料的差异。结果表明:复合材料致密度随着编织体预热温度的提高而增大,提高预热温度可有效减少复合材料内部孔洞和纤维偏聚等浸渗缺陷;复合材料的拉伸强度随纤维预制体预热温度的提高而显著降低。其中,在预热温度500℃、浸渗温度720℃、浸渗压力7 MPa和保压时间20 min的工艺条件下,所制备的3D-Cf/Al复合材料致密度为97.3%,拉伸强度为777.8 MPa,弹性模量为186.1GPa。

  8. 钢包预热过程热应力影响因子及预报模型%Classification of thermomechanical impact factors and prediction model for ladle preheating

    Institute of Scientific and Technical Information of China (English)

    金胜利; Harald Harmuth; Dietmar Gruber; Thomas Auer; 李亚伟

    2011-01-01

    Linear elastic models were established by means of finite element code ABAQUS to simulate the thermomechanical behavior of steel ladle during preheating. The impact factors of ladle lining thickness and material properties on the maximum stress at steel ladle linings and end temperature at the steel shell were determined. Prediction models were built with partial least squares algorithm based on the above simulation results. The results show that the material properties of working lining plays a major role in the maximum compressive stress, maximum tensile stress and end temperature whether it includes an insulation or not. Compared with the ladle without an insulation, the importance of permanent lining to the maximum stress is reduced significantly by using the insulation.%运用有限元软件ABAQUS建立钢包包衬的线性弹性模型,模拟钢包预热过程包衬的热应力,分析包衬厚度及其材料物理性能对包衬内最大热应力和钢壳表面温度的影响;采用偏最小二乘法建立包衬厚度及材料物理性能与包衬内最大热应力、钢壳表面温度间的预报模型.结果表明,工作衬材料物理性能对包衬最大应力和钢壳表面温度起主要影响作用;较之于无绝热衬,有绝热衬钢包永久衬材料物理性能对钢包热应力和钢壳表面温度的影响作用显著降低.

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

    Index Scriptorium Estoniae

    Tammeorg, Teele

    2010-01-01

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

  10. Air Cleaning Technologies

    Science.gov (United States)

    2005-01-01

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

  11. Clean Air and Water

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

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

  12. AIR / SEA RESCUE LAUNCHES

    Directory of Open Access Journals (Sweden)

    W.H. Rice

    2012-02-01

    Full Text Available The Motor Boat Wing of the South African Air Force was inaugurated some thirty eight years ago.With its main base at Gordon's Bay, the wing was formed to operate the various marine craft used to provide a service to the flying component of the South African Air Force. Its main function was to be air/sea rescue, but it also had to man and maintain armoured target boats, seaplane tenders, marine tenders and the 'bomb scows', used for recovering practise bombs and missiles and for laying and lifting moorings.

  13. Mid-air Acrobatics

    Institute of Scientific and Technical Information of China (English)

    LlU FENG'AN

    2011-01-01

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

  14. Air Quality Monitoring Programme

    DEFF Research Database (Denmark)

    Kemp, K.; Palmgren, F.

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

  15. Air/Water Purification

    Science.gov (United States)

    1992-01-01

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

  16. Olefin metathesis in air

    Directory of Open Access Journals (Sweden)

    Lorenzo Piola

    2015-10-01

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

  17. Air issues update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    A government sponsored poll revealed that the primary environmental concern for Ontarians in 2000 was air pollution. While scientists tend to focus on smog episodes, greenhouse gas emissions, acid rain or emissions of toxic pollutants, the public shows concern in more practical terms such as the overall impact of poor air quality on people and the ecosystem, and how this will affect future life on earth. It was emphasized that policy makers should try to apply this holistic approach to the complex issues associated with air quality. Climate change, acid rain and ultraviolet radiation are some examples of how air emissions impact on ecosystems. Other examples include elevated levels of mercury in otters in Ontario. Climate change has also been linked with the re-acidification of lakes, as droughts typically occur in years following an El Nino cycle which has been pronounced as a possible consequence of greenhouse gas emissions. The Environmental Commissioner of Ontario (ECO) has reviewed the efforts of the Ontario Ministry of the Environment (MOE) regarding the regulation of air quality. The MOE has proposed several initiatives, including newer air dispersion models into legislation, establishing a new consultation process for applying new air quality standards to emission sources, an expansion of the Drive Clean Program, and a discussion paper on a proposed emission cap and trade system. This paper presents ECO's review of these initiatives and provides updates on other air quality issues such as control of emissions from Ontario's transportation, industrial and electricity sectors. It also described policy proposals related to standard-setting for air pollutants, as well as the newly adopted Canada-wide Standards for Particulate Matter and Ozone. A progress report on Ontario's Anti-Smog Action Plan (ASAP) confirms that major reductions in NO{sub x} expected from Ontario's coal-fired power plants never materialized. Emissions of nitrogen oxide

  18. Effect of air ingress on the energy performance of coal fired thermal power plants

    International Nuclear Information System (INIS)

    Ingress of air in boilers leads to drops in energy efficiency. This paper presents the effects of air ingress in the combustion zone, post-combustion zone and air pre-heater (APH) on the energy efficiency and loading capacity of a coal fired thermal power plant operating on fuel with high ash (35-45%). The optimal O2 in the flue gas for a pulverized coal fired system is 3.5% (corresponding to 20% excess air). The operating values are in the range of 4.2-6.0% in membrane type boilers and up to 10% in refractory type boilers (after sustained periods of operation). The leakage rate of boilers (up to the entrance of the APH) is designed at 0.2% while the average operating values are 7.25% for membrane type enclosures and 33.61% for refractory enclosures. The leakage rate of the APH is designed at 5.0% while the operating values range from 13.66% to 20.13% for rotary and tubular APHs. When the O2 in the combustion zone varies from 3.5% to 8.0%, efficiency drops of 2.0% points are experienced in the boiler and turbine separately, and the gross overall efficiency drop is ∼3.0% points. The units do not experience any capacity drop up to an O2 in the flue gas of 6.0% before the APH. At an O2 in the flue gas (before APH) of 7.2%, a mild limitation on the unit capacity of around 2-3% is experienced. When O2 in the flue gas (before APH) reaches a level of 9.0%, 20% capacity drop of the unit is experienced due to which the plant load cannot be raised higher than 80%. Beyond the level of 9.0% (rare occurrence), the unit is quite difficult to operate and has to be taken off for overhaul

  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. Emission Facilities - Air Emission Plants

    Data.gov (United States)

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

  1. Introduction to Indoor Air Quality

    Science.gov (United States)

    ... US Environmental Protection Agency Search Search Indoor Air Quality (IAQ) Share Facebook Twitter Google+ Pinterest Contact Us ... Indoor Air Quality An Introduction to Indoor Air Quality IAQ & Health Causes of IAQ Problems Identifying IAQ ...

  2. Ambient Air Quality Data Inventory

    Data.gov (United States)

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

  3. Ambient Air Quality Data Inventory

    Data.gov (United States)

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

  4. Air Quality Guide for Ozone

    Science.gov (United States)

    Local Air Quality Conditions Zip Code: State : My Current Location Air Quality Guide for Ozone Ground-level ozone is one of our nation’s most common air pollutants. Use the chart below to help reduce ...

  5. Air transportation energy efficiency

    Science.gov (United States)

    Williams, L. J.

    1977-01-01

    The energy efficiency of air transportation, results of the recently completed RECAT studies on improvement alternatives, and the NASA Aircraft Energy Efficiency Research Program to develop the technology for significant improvements in future aircraft were reviewed.

  6. Criteria Air Emissions Trends

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Emissions Trends site provides national trends of criteria pollutant and precursor emissions data based on the the National Emissions Inventory (NEI) from...

  7. Indoor air quality

    International Nuclear Information System (INIS)

    Indoor Air Quality is rapidly becoming a major environmental concern because a significant amount of people spend a substantial amount of time in a variety of different indoor environments. Health effects from indoor pollutants fall into two categories: those that are experienced immediately after exposure and those that do not show up until years later. They are: radon, formaldehyde, asbestos, lead and household organic chemicals. The authors presented a source-by-source look at the most common indoor air pollutants, their potential health effects, and ways to reduce their levels in the home. There are three basic strategies to improve indoor air quality: one method is source control, another is through ventilation improvements, and the third is the utilization of some sort of mechanical device such as air cleaners

  8. Transportation and Air Quality

    Science.gov (United States)

    ... factors research. - Modeling & Inventories - Testing & Measuring Emissions - Clean Automotive Technologies - Emission Factors Research This page is maintained by EPA's Office of Transportation and Air Quality (OTAQ) . For more: About Us | Get E-mail ...

  9. Air conditioning system

    Science.gov (United States)

    Lowenstein, Andrew; Miller, Jeffrey; Gruendeman, Peter; DaSilva, Michael

    2005-02-01

    An air conditioner comprises a plurality of plates arranged in a successively stacked configuration with portions thereof having a spaced apart arrangement, and defining between successive adjacent pairs of plates at the spaced apart portions a first and second series of discrete alternating passages wherein a first air stream is passed through the first series of passages and a second air stream is passed through the second series of passages; and said stacked configuration of plates forming integrally therewith a liquid delivery means for delivering from a source a sufficient quantity of a liquid to the inside surfaces of the first series of fluid passages in a manner which provides a continuous flow of the liquid from a first end to a second end of the plurality of plates while in contact with the first air stream.

  10. Indoor air pollution

    International Nuclear Information System (INIS)

    Although official efforts to control air pollution have traditionally focused on outdoor air, it is now apparent that elevated contaminant concentrations are common inside some private and public buildings. Concerns about potential public health problems due to indoor air pollution are based on evidence that urban residents typically spend more than 90 percent of their time indoors, concentrations of some contaminants are higher indoors than outdoors, and for some pollutants personal exposures are not characterized adequately by outdoor measurements. Among the more important indoor contaminants associated with health or irritation effects are passive tobacco smoke, radon decay products, carbon monoxide, nitrogen dioxide, formaldehyde, asbestos fibers, microorganisms and aeroallergens. Efforts to assess health risks associated with indoor air pollution are limited by insufficient information about the number of people exposed, the pattern and severity of exposures, and the health consequences of exposures. An overall strategy should be developed to investigate indoor exposures, health effects, control options, and public policy alternatives

  11. Indoor air quality

    International Nuclear Information System (INIS)

    Rising energy prices, among other factors, have generated an incentive to reduce ventilation rates and thereby reduce the cost of heating and cooling buildings. Reduced ventilation in buildings may significantly increase exposure to indoor air pollution and perhaps have adverse effects on occupant health and comfort. Preliminary findings suggest that reduced ventilation may adversely affect indoor air quality unless appropriate control strategies are undertaken. The strategies used to control indoor air pollution depend on the specific pollutant or class of pollutants encountered, and differ somewhat depending on whether the application is to an existing building or a new building under design and construction. Whenever possible, the first course of action is prevention or reduction of pollutant emissions at the source. In most buildings, control measures involve a combination of prevention, removal, and suppression. Common sources of indoor air pollution in buildings, the specific pollutants emitted by each source, the potential health effects, and possible control techniques are discussed

  12. Radioactive air sampling methods

    CERN Document Server

    Maiello, Mark L

    2010-01-01

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

  13. Regional Air Quality Data

    Data.gov (United States)

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

  14. Air Data Calibration Facility

    Data.gov (United States)

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

  15. INDOOR AIR QUALITY ANALYSIS

    OpenAIRE

    Wang, Xin

    2010-01-01

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

  16. Indoor Air Pollution

    OpenAIRE

    Kirk R Smith

    2003-01-01

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

  17. INDOOR AIR POLLUTION

    OpenAIRE

    Ahmet Soysal; Yucel Demiral

    2007-01-01

    The existance of hazardious materials including biological, chemical, and physical agents such as carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, radon, volotile organic compounds, microorganisms in houses and the other non-industrilized buildings have been defined as “indoor air pollution”. Indoor air pollutants could possible arised from inside or outside environment and categorized into six subgroups. Almost 80% Turkish population have living in the urban areas...

  18. Air Distribution in Rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The research on air distribution in rooms is often done as full-size investigations, scale-model investigations or by Computational Fluid Dynamics (CFD). New activities have taken place within all three areas and this paper draws comparisons between the different methods. The outcome of the l......EA sponsored research "Air Flow Pattern within Buildings" is used for comparisons in some parts of the paper because various types of experiments and many countries are involved....

  19. Hot Air Engines

    OpenAIRE

    P. Stouffs

    2011-01-01

    Invented in 1816, the hot-air engines have known significant commercial success in the nineteenth century, before falling into disuse. Nowadays they enjoy a renewed interest for some specific applications. The "hot-air engines" family is made up of two groups: Stirling engines and Ericsson engines. The operating principle of Stirling and Ericsson engines, their troubled history, their advantages and their niche applications are briefly presented, especially in the field of...

  20. Air gun test facility

    International Nuclear Information System (INIS)

    This paper describes a facility that is potentially useful in providing data for models to predict the effects of nuclear explosions on cities. IIT Research Institute has a large air gun facility capable of launching heavy items of a wide variety of geometries to velocities ranging from about 80 fps to 1100 fps. The facility and its capabilities are described, and city model problem areas capable of investigation using the air gun are presented

  1. Canada's Clean Air Act

    International Nuclear Information System (INIS)

    This paper provided an outline of Canada's Clean Air Act and examined some of the regulatory changes that will occur as a result of its implementation. The Act is being introduced to strengthen the legislative basis for taking action on reducing air pollution and GHGs, and will allow the government to regulate both indoor and outdoor air pollutants and GHGs. The Act will require the Ministers of the Environment and Health to establish national air quality objectives, as well as to monitor and report on their attainment. The Canadian Environmental Protection Act will be amended to enable the government to regulate the blending of fuels and their components. The Motor Vehicle Fuel Consumption Standards Act will also be amended to enhance the government's authority to regulate vehicle fuel efficiency. The Energy Efficiency Act will also be expanded to allow the government to set energy efficiency standards and labelling requirements for a wider range of consumer and commercial products. The Act will commit to short, medium and long-term industrial air pollution targets. Regulations will be proposed for emissions from industry; on-road and off-road vehicles and engines; and consumer and commercial products. It was concluded that the Government of Canada will continue to consult with provinces, territories, industries and Canadians to set and reach targets for the reduction of both indoor and outdoor air pollutants and GHG emissions. 6 figs

  2. Clean air Hamilton

    Energy Technology Data Exchange (ETDEWEB)

    McCarry, B.E. [McMaster Univ., Hamilton, ON (Canada)

    2002-07-01

    The industrial City of Hamilton is located on Lake Ontario, downwind from the Ohio Valley. The Hamilton Air Quality Initiative (HAQI) was divided in several phases, one of which is Clean Air Hamilton. This most recent phase was described in this presentation. Two major goals of this phase were: to ensure that the City of Hamilton has the best air quality of any major urban area in Ontario, and to reduce the emissions of greenhouse gases by 20 per cent compared to the levels in 1990. There were five main objectives to this initiative, namely: (1) the identification of priority air quality issues, (2) achieving an understanding of air quality issues, (3) the identification of sources, the evaluation of impacts and the recommendation of solutions, (4) the assessment of human health, and (5) the identification of further research. The reduction of air quality impacts is progressing through the support provided to the Drive Clean Program, the discouragement of vehicle idling, the support to car pooling initiatives, and the promotion of green vehicles. The implementation of pollution control technologies is taking place on the industrial side, as well as the development of plans to reduce steel industry emissions, the development of energy conservation measures and the promotion of green building practices. Efforts are being deployed over fleet greening partnerships, community tree planting program, an international air conference, an electronic information network linking the United States and the communities of Southern Ontario, a road dust study, a truck emissions research project, the assessment of human health impacts, and finally methods for the monitoring of local improvements. figs.

  3. Computers in Air Defence

    Directory of Open Access Journals (Sweden)

    P. V.S. Rao

    1987-10-01

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

  4. Indoor air pollution

    International Nuclear Information System (INIS)

    Indoor air pollution after being a neglected subject for a number of years, is attracting attention recently because it is a side effect of energy crisis. About 50% of world's 6 billion population, mostly in developing countries, depend on biomass and coal in the form of wood, dung and crop residues for domestic energy because of poverty. These materials are burnt in simple stoves with incomplete combustion and infants, children and women are exposed to high levels of indoor air pollution for a considerable period, approximately between 2-4 hours daily. Current worldwide trade in wood fuel is over US $7 billion and about 2 million people are employed full time in production and marketing it. One of the most annoying and common indoor pollutant in both, developing and developed countries, is cigarette smoke. Children in gas-equipped homes had higher incidences of respiratory disease. Babies' DNA can be damaged even before they are born if their mothers breathe polluted air. Exposure to indoor air pollution may be responsible for nearly 2 million excess deaths in developing countries and for 4% of the global burden of the disease. Only a few indoor pollutants have been studied in detail. Indoor air pollution is a major health threat on which further research is needed to define the extent of the problem more precisely and to determine solutions by the policy-makers instead of neglecting it because sufferers mostly belong to Third World countries. (author)

  5. Infants Can Study Air Science.

    Science.gov (United States)

    Ward, Alan

    1983-01-01

    Provided are activities and demonstrations which can be used to teach infants about the nature of air, uses of air, and objects that fly in the air. The latter include airships, hot-air balloons, kites, parachutes, airplanes, and Hovercraft. (JN)

  6. Selection of Air Terminal Device

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

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

  7. Comparison Based on Exergetic Analyses of Two Hot Air Engines: A Gamma Type Stirling Engine and an Open Joule Cycle Ericsson Engine

    Directory of Open Access Journals (Sweden)

    Houda Hachem

    2015-10-01

    Full Text Available In this paper, a comparison of exergetic models between two hot air engines (a Gamma type Stirling prototype having a maximum output mechanical power of 500 W and an Ericsson hot air engine with a maximum power of 300 W is made. Referring to previous energetic analyses, exergetic models are set up in order to quantify the exergy destruction and efficiencies in each type of engine. The repartition of the exergy fluxes in each part of the two engines are determined and represented in Sankey diagrams, using dimensionless exergy fluxes. The results show a similar proportion in both engines of destroyed exergy compared to the exergy flux from the hot source. The compression cylinders generate the highest exergy destruction, whereas the expansion cylinders generate the lowest one. The regenerator of the Stirling engine increases the exergy resource at the inlet of the expansion cylinder, which might be also set up in the Ericsson engine, using a preheater between the exhaust air and the compressed air transferred to the hot heat exchanger.

  8. The Clean Air Act

    International Nuclear Information System (INIS)

    The Clean Air Act amendments alter the complex laws affecting atmospheric pollution and at the same time have broad implications for energy. Specifically, the Clean Air Act amendments for the first time deal with the environmental problem of acid deposition in a way that minimizes energy and economic impacts. By relying upon a market-based system of emission trading, a least cost solution will be used to reduce sulfur dioxide (SO2) emissions by almost 40 percent. The emission trading system is the centerpiece of the Clean Air Act (CAA) amendments effort to resolve energy and environmental interactions in a manner that will maximize environmental solutions while minimizing energy impacts. This paper will explore how the present CAA amendments deal with the emission trading system and the likely impact of the emission trading system and the CAA amendments upon the electric power industry

  9. Liquid air cycle engines

    Science.gov (United States)

    Rosevear, Jerry

    1992-01-01

    Given here is a definition of Liquid Air Cycle Engines (LACE) and existing relevant technologies. Heat exchanger design and fabrication techniques, the handling of liquid hydrogen to achieve the greatest heat sink capabilities, and air decontamination to prevent heat exchanger fouling are discussed. It was concluded that technology needs to be extended in the areas of design and fabrication of heat exchangers to improve reliability along with weight and volume reductions. Catalysts need to be improved so that conversion can be achieved with lower quantities and lower volumes. Packaging studies need to be investigated both analytically and experimentally. Recycling with slush hydrogen needs further evaluation with experimental testing.

  10. Unit for air decontamination

    International Nuclear Information System (INIS)

    To fulfill the applicable requirements of safety to the ventilation systems in nuclear facilities, it is necessary to make a cleaning of the air that hurtles to the atmosphere. For that which was designed and it manufactured an unit for decontamination of the air for the Pilot plant of production of Nuclear Fuel that this built one with national parts, uses Hepa national filters and the design can adapt for different dimensions of filters, also can be added a lodging for a prefilter or to adopt two Hepa filters. (Author)

  11. Air the excellent canopy

    CERN Document Server

    Fahy, F

    2013-01-01

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

  12. Air Freight and Logistics Services

    OpenAIRE

    Kiso, Fadila; Deljanin, Abidin

    2009-01-01

    Air transport industry has gradually increased its share of global passenger and freight traffic, and this trend has accelerated in the last 40 years. For the past decade, air-freight traffic growth has outpaced air passenger traffic growth by 1-2% each year. In the past, air-freight sector offered limited services, with heavy reliance on several intermediaries and a significant dependence on air passenger operations. The sector can now be characterized as a sophisticated, innovative one, rel...

  13. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  14. Indoor air pollution

    International Nuclear Information System (INIS)

    Indoor air pollution is a potential risk to human health. Prolonged exposure to indoor pollutants may cause various infectious, allergic and other diseases. Indoor pollutants can emanate from a broad array of internal and external sources. Internal sources include building and furnishing materials, consumer and commercial products, office equipment, micro-organisms, pesticides and human occupants activities. External sources include soil, water supplies and outside makeup air. The main indoor air pollutants of concern are inorganic gases, formaldehyde and other volatile organic compounds, pesticides, radon and its daughters, particulates and microbes. The magnitude of human exposure to indoor pollutants can be estimated or predicted with the help of mathematical models which have been developed using the data from source emission testing and field monitoring of pollutants. In order to minimize human exposure to indoor pollutants, many countries have formulated guidelines / standards for the maximum permissible levels of main pollutants. Acceptable indoor air quality can be achieved by controlling indoor pollution sources and by effective ventilation system for removal of indoor pollutants. (author)

  15. Indoor air quality research

    International Nuclear Information System (INIS)

    The various types of pollutant found in indoor air are introduced and the effects on the health of the occupants of buildings summarized. The ''sick'' building syndrome is described in detail and the need for further investigation into its causes and remedies is stressed. 8 tabs

  16. Mid-air Acrobatics

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  17. Russia air management program

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  18. Air Quality Monitoring Programme

    DEFF Research Database (Denmark)

    Kemp, K.; Palmgren, F.

    The Danish Air Quality Monitoring Programme (LMP IV) has been revised in accordance with the Framework Directive and the first three daughter directives of SO2, NOx/NO2, PM10, lead, benzene, CO and ozone. PM10 samplers are under installation and the installation will be completed during 2002...

  19. Indoor Air Quality

    DEFF Research Database (Denmark)

    Selman, Ayser Dawod; Heiselberg, Per

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

  20. Hexane Air Combustion

    CERN Document Server

    Boettcher, Philipp A; Shepherd, Joseph E

    2010-01-01

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

  1. Images in the Air

    Science.gov (United States)

    Riveros, H. G.; Rosenberger, Franz

    2012-01-01

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

  2. Ames Air Revitalization

    Science.gov (United States)

    Huang, Roger Z.

    2015-01-01

    This is an informal presentation presented to the University of Colorado, Boulder Bioastronautics group seminar. It highlights the key focal areas of the Air Revitalization Group research over the past year, including progress on the CO2 Removal and Compression System, testing of CDRA drying bed configurations, and adsorption research.

  3. Hydrogen-air detonations

    International Nuclear Information System (INIS)

    General gaseous detonation propagation phenomena are briefly discussed. The importance of cellular structure and cell size to detonation initiation, transmission and failure is emphasized. Experimental measurements of cell size lambda for hydrogen-air-carbon dioxide mixtures are presented; the hydrogen/air volume ratios range between 0.16 and 1.5 and the carbon dioxide mole fractions are 0, 0.05, 0.10 and 0.15. Cell sizes are a minimum for both diluted and undiluted hydrogen-air mixtures near stoichiometric (i.e., hydrogen/air = 0.4). Minimum cell sizes for carbon dioxide mole fractions of 0, 0.05, 0.10 and 0.15 are 1.51, 2.05, 4.2 and 15.0 cm, respectively. Results of large- and small-scale critical tube diameter (d/sub c/) measurements are presented and show good agreement with the empirical scaling law, d/sub c/ = 13 lambda. Mean detonation velocities and pressures have been measured and compared to the theoretical Chapman-Jouguet values

  4. Air-cleaning apparatus

    International Nuclear Information System (INIS)

    An air-cleaning, heat-exchange apparatus includes a main housing portion connected by means of an air inlet fan to the kitchen exhaust stack of a restaurant. The apparatus includes a plurality of heat exchangers through which a heat-absorptive fluid is circulated, simultaneously, by means of a suitable fluid pump. These heat exchangers absorb heat from the hot exhaust gas, out of the exhaust stack of the restaurant, which flows over and through these heat exchangers and transfers this heat to the circulating fluid which communicates with remote heat exchangers. These remote heat exchangers further transfer this heat to a stream of air, such as that from a cold-air return duct for supplementing the conventional heating system of the restaurant. Due to the fact that such hot exhaust gas is heavily grease laden , grease will be deposited on virtually all internal surfaces of the apparatus which this exhaust gas contacts. Consequently, means are provided for spraying these contacted internal surfaces , as well as the hot exhaust gas itself, with a detergent solution in which the grease is soluble, thereby removing grease buildup from these internal surfaces

  5. Learning AirWatch

    CERN Document Server

    Dunkerley, Mark

    2015-01-01

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

  6. Air quality indicators

    International Nuclear Information System (INIS)

    This report proposes and describes in detail several air quality indicators that may be used to describe population exposure. The suggested indicators account for temporal and spatial patterns of pollution and movements of individuals between different micro-environments. The Air Quality Indicator /AQI) should represent both the spatial and temporal aspects of pollution exposure that may have important effects on health. Two indicators are needed, the Population Air Quality Indicator and the Individual Air Quality Indicator. Mean concentrations, 98th percentile and maximum values are the traditional indicators for estimating exposure. the temporal variability of PM-10 and NO2, however, is here described by means of: 1) The rate of change of pollution as the difference between two consecutive hourly values and of 2) episodes, described in terms of number, duration and winter episode period, maximum concentration in the episode and integrated episode exposure (episode AOT50/100). The spatial variation of AQIs can be described in several ways, e.g.: 1) Concentrations in neighbouring grid squares can be compared as an indication of spatial variation and 2) point estimates can be compared to grid values for a description of variation within a grid. Both methods are presented here. A test of the representativity of static point estimates for pollution exposure is to compare them to an estimate of air pollution exposure accounting for movements between different locations, obtained using diaries. The ultimate aim of AQIs is to describe the population exposure to ambient pollution. This is done by estimating the number of people exposed using different characteristics of AQIs. The data used to describe these indicators originates from dispersion modelling of short-term air pollution concentrations in Oslo. Two series of data are used. One represents hour-for hour concentrations in the 1 km2 grid system covering the city of Oslo, winter 1994/95, calculated by the grid

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

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

    Science.gov (United States)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

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

  9. Air movement - good or bad?

    DEFF Research Database (Denmark)

    Toftum, Jørn

    2004-01-01

    Air movement - good or bad? The question can only be answered by those who are exposed when they are exposed. Human perception of air movement depends on environmental factors including air velocity, air velocity fluctuations, air temperature, and personal factors such as overall thermal sensation...... and activity level. Even for the same individual, sensitivity to air movement may change from day to day as a result of e.g. different levels of fatigue. Based on existing literature, the current paper summarizes factors influencing the human perception of air movement and attempts to specify in...... general terms when air movement is desirable and when it is not. At temperatures up to 22-23oC, at sedentary activity and with occupants feeling neutral or cooler there is a risk of air movement being perceived as unacceptable, even at low velocities. In particular, a cool overall thermal sensation...

  10. EN EL AIRE / In the air

    Directory of Open Access Journals (Sweden)

    Andrés López Fernández

    2011-11-01

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  13. Enhancing indoor air quality –The air filter advantage

    OpenAIRE

    Vannan Kandi Vijayan; Haralappa Paramesh; Sundeep Santosh Salvi; Alpa Anil Kumar Dalal

    2015-01-01

    Air pollution has become the world's single biggest environmental health risk, linked to around 7 million deaths in 2012 according to a recent World Health Organisation (WHO) report. The new data further reveals a stronger link between, indoor and outdoor air pollution exposure and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. The role of air pollution in the development of respiratory diseases, including acute respiratory in...

  14. 反应堆压力容器下底圆J型坡口隔离层堆焊预热问题分析及其处理%Analysis and Treatment of Preheating Deviation Problems of J Type Groove Buttering on Lower Dome of Reactor Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    吴义党; 杨志鹏; 刘鸣宇; 朱从斌; 徐晓冬; 张春来

    2012-01-01

    介绍了反应堆压力容器下底圆中子测量管的焊接工艺.基于某制造厂发生的该焊缝相关的下底圆J型坡口隔离层堆焊预热质量问题,分析了预热、层间温度等焊缝质量影响要素及该质量问题的处理方案,为今后类似问题的处理和提高J型坡口隔离层的堆焊质量提供参考.%The welding procedure of instruction tube on lower dome of reactor pressure vessel was briefly introduced. The affecting factors for quality of welding joint such as preheating and interpass temperature were analyzed based on a preheating quality problem of J type groove buttering happened on a certain manufacturer. Additionally, the related disposition measures were summarized. The analysis can provide the reference for the treatment of similar problem and help improve the welding quality of J type groove buttering layer.

  15. Air sampling in the workplace

    International Nuclear Information System (INIS)

    This report provides technical information on air sampling that will be useful for facilities following the recommendations in the NRC's Regulatory Guide 8.25, Revision 1, ''Air sampling in the Workplace.'' That guide addresses air sampling to meet the requirements in NRC's regulations on radiation protection, 10 CFR Part 20. This report describes how to determine the need for air sampling based on the amount of material in process modified by the type of material, release potential, and confinement of the material. The purposes of air sampling and how the purposes affect the types of air sampling provided are discussed. The report discusses how to locate air samplers to accurately determine the concentrations of airborne radioactive materials that workers will be exposed to. The need for and the methods of performing airflow pattern studies to improve the accuracy of air sampling results are included. The report presents and gives examples of several techniques that can be used to evaluate whether the airborne concentrations of material are representative of the air inhaled by workers. Methods to adjust derived air concentrations for particle size are described. Methods to calibrate for volume of air sampled and estimate the uncertainty in the volume of air sampled are described. Statistical tests for determining minimum detectable concentrations are presented. How to perform an annual evaluation of the adequacy of the air sampling is also discussed

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

    Science.gov (United States)

    Palliser, Janna

    2011-01-01

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

  17. Indoor Air Quality in Schools: Clean Air Is Good Business.

    Science.gov (United States)

    Guarneiri, Michele A.

    2003-01-01

    Describes the effect of poor indoor air quality (IAQ) on student health, the cost of safeguarding good IAQ, the cause of poor IAQ in schools, how to tell whether a school has an IAQ problem, and how the U.S. Environmental Protection Agency can help schools improve indoor air quality though the use of their free "Indoor Air Quality Tools for…

  18. Properties of air and combustion products of fuel with air

    Science.gov (United States)

    Poferl, D. J.; Svehla, R. A.

    1975-01-01

    Thermodynamic and transport properties have been calculated for air, the combustion products of natural gas and air, and combustion products of ASTM-A-1 jet fuel and air. Properties calculated include: ratio of specific heats, molecular weight, viscosity, specific heat, thermal conductivity, Prandtl number, and enthalpy.

  19. 石墨烯薄膜的前驱气体预热化学气相沉积快速制备方法%Fast synthesis of graphene films by precursor-gas preheating thermal chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    余崇圣; 魏大鹏

    2015-01-01

    Graphene has been considered as promising material for next generation transparent electrodes due to its excellent optical ,electrical ,and mechanical properties ,but unfortunately the practical use of graphene in end‐product devices has not been demonstrated since the yield ,size and uniformity problems are yet to be solved to satisfy industrial standards .Here we show large‐area monolayer graphene films by precursor‐gas preheating thermal chemical vapor deposition (PT‐CVD) ,w hich enabled mass‐produced and larger production of graphene film over 300 mm × 300 mm PET substrate area with an optical transmittance of over 95% and a sheet resist‐ance of (146 ± 15) Ω/sq .The uniformity ,transmittance and sheet resistance properties of graphene had been characterized by using scanning electron microscope (SEM ) ,Raman spectroscopy ,UV‐Vis spectrophotometer and four point probe resistivity tester .Finally ,we successfully patterned graphene micro/nano‐structure and solved vacuum lamination problems for graphene‐based truly multi‐touch capacitive touch panels in mobile phones .%石墨烯具有优异的光学、电学和力学等性能而备受人们关注,但是目前石墨烯材料受产量、尺寸和均匀性等因素的限制,以至于在终端产品上还没有形成真正的应用。主要阐述了一种利用前驱气体预热化学气相沉积法(PT‐CVD)快速制备大面积单层石墨烯薄膜方法,实现石墨烯薄膜批量制备和大面积转移在300 m m ×300 m m 面积的聚对苯二甲酸乙二醇酯衬底上,并获得在400~800 n m光波段下大于95%的光透过率和(146±15)Ω/sq的方块电阻。分别利用扫描电镜、共聚焦拉曼光谱仪、紫外‐可见分光光度计和四探针设备等检测了前驱气体预热化学气相沉积法制备的石墨烯薄膜的均匀性、透过率和方块电阻等参数特性。最后,通过解决了石墨烯微纳米线路结构和真空贴合等关

  20. Aeromicrobiology/air quality

    Science.gov (United States)

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

    2009-01-01

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

  1. Air Pollution in Europe

    International Nuclear Information System (INIS)

    In spite of improvements relative to air pollution, there is still much to do. more than thirty millions of European people are exposed to sulfur dioxide concentrations superior to guide values for health fixed by European Union, 20% of ecosystems in Europe are above the critical charges in the area of acidification and 33% concern eutrophication. Relative to the carbon dioxide, it is not sure that European Union realize the objective to stabilize the emissions for the year 2000 at the level of the year 1990, because of the increasing of automobile traffic and the energy consumption. Four subjects are presented: the climatic change, acidification and eutrophication, tropospheric ozone and air quality. (N.C.)

  2. Hot Air Engines

    Directory of Open Access Journals (Sweden)

    P. Stouffs

    2011-01-01

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

  3. Air transport system

    CERN Document Server

    Schmitt, Dieter

    2016-01-01

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

  4. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

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

  5. Urban air quality

    International Nuclear Information System (INIS)

    Since 1950 the world population has more than doubled, and the global number of cars has increased by a factor of 10. In the same period the fraction of people living in urban areas has increased by a factor of 4. In year 2000 this will amount to nearly half of the world population. About 20 urban regions will each have populations above 10 million people. Seen over longer periods, pollution in major cities tends to increase during the built up phase, they pass through a maximum and are then again reduced, as abatement strategies are developed. In the industrialised western world urban air pollution is in some respects in the last stage with effectively reduced levels of sulphur dioxide and soot. In recent decades however, the increasing traffic has switched the attention to nitrogen oxides, organic compounds and small particles. In some cities photochemical air pollution is an important urban problem, but in the northern part of Europe it is a large-scale phenomenon, with ozone levels in urban streets being normally lower than in rural areas. Cities in Eastern Europe have been (and in many cases still are) heavily polluted. After the recent political upheaval, followed by a temporary recession and a subsequent introduction of new technologies, the situation appears to improve. However, the rising number of private cars is an emerging problem. In most developing countries the rapid urbanisation has so far resulted in uncontrolled growth and deteriorating environment. Air pollution levels are here still rising on many fronts. Apart from being sources of local air pollution, urban activities are significant contributors to transboundary pollution and to the rising global concentrations of greenhouse gasses. Attempts to solve urban problems by introducing cleaner, more energy-efficient technologies will generally have a beneficial impact on these large-scale problems. Attempts based on city planning with a spreading of the activities, on the other hand, may generate

  6. Urban air quality

    Science.gov (United States)

    Fenger, Jes

    Since 1950 the world population has more than doubled, and the global number of cars has increased by a factor of 10. In the same period the fraction of people living in urban areas has increased by a factor of 4. In year 2000 this will amount to nearly half of the world population. About 20 urban regions will each have populations above 10 million people. Seen over longer periods, pollution in major cities tends to increase during the built up phase, they pass through a maximum and are then again reduced, as abatement strategies are developed. In the industrialised western world urban air pollution is in some respects in the last stage with effectively reduced levels of sulphur dioxide and soot. In recent decades however, the increasing traffic has switched the attention to nitrogen oxides, organic compounds and small particles. In some cities photochemical air pollution is an important urban problem, but in the northern part of Europe it is a large-scale phenomenon, with ozone levels in urban streets being normally lower than in rural areas. Cities in Eastern Europe have been (and in many cases still are) heavily polluted. After the recent political upheaval, followed by a temporary recession and a subsequent introduction of new technologies, the situation appears to improve. However, the rising number of private cars is an emerging problem. In most developing countries the rapid urbanisation has so far resulted in uncontrolled growth and deteriorating environment. Air pollution levels are here still rising on many fronts. Apart from being sources of local air pollution, urban activities are significant contributors to transboundary pollution and to the rising global concentrations of greenhouse gasses. Attempts to solve urban problems by introducing cleaner, more energy-efficient technologies will generally have a beneficial impact on these large-scale problems. Attempts based on city planning with a spreading of the activities, on the other hand, may generate

  7. Air Facility System (AFS) Widget

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Facility System (AFS) widget allows users to enter a specific location and retrieve facilities in the area of interest for stationary sources of air...

  8. Ozone - Current Air Quality Index

    Science.gov (United States)

    ... more announcements Air Quality Basics Air Quality Index | Ozone | Particle Pollution | Smoke from fires | What You Can ... Partners Kids Movies NAQ Conferences NOAA Older Adults Ozone Particle Pollution (PM2.5, PM10) Publications Publicaciones (En ...

  9. State of the Air 2015

    Science.gov (United States)

    ... Banners Social Media What's the State of Your Air ? Home > 2015 > States States State List FAQ Understanding ... Environment: Act Locally What You Can Do Healthy Air News Facebook Twitter Google Plus Instagram © American Lung ...

  10. Air Compliance Complaint Database (ACCD)

    Data.gov (United States)

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

  11. Air Markets Program Data (AMPD)

    Data.gov (United States)

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

  12. Air System Information Management

    Science.gov (United States)

    Filman, Robert E.

    2004-01-01

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

  13. Air transparent soundproof window

    International Nuclear Information System (INIS)

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

  14. Air transparent soundproof window

    Directory of Open Access Journals (Sweden)

    Sang-Hoon Kim

    2014-11-01

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

  15. Air transparent soundproof window

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang-Hoon, E-mail: shkim@mmu.ac.kr [Division of Marine Engineering, Mokpo National Maritime University, Mokpo 530-729, R. O. Korea (Korea, Republic of); Lee, Seong-Hyun [Korea Institute of Machinery and Materials, Yuseong-Gu, Daejeon 305-343, R. O. Korea (Korea, Republic of)

    2014-11-15

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

  16. Human preference for air movement

    DEFF Research Database (Denmark)

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

    2002-01-01

    Human preference for air movement was studied at slightly cool, neutral, and slightly warm overall thermal sensations and at temperatures ranging from 18 deg.C to 28 deg.C. Air movement preference depended on both thermal sensation and temperature, but large inter-individual differences existed...... between subjects. Preference for less air movement was linearly correlated with draught discomfort, but the percentage of subjects who felt draught was lower than the percentage who preferred less air movement....

  17. Air quality assessment for Portugal

    OpenAIRE

    Monteiro, A; Miranda, A. I.; C. Borrego; R. Vautard

    2007-01-01

    According to the Air Quality Framework Directive, air pollutant concentration levels have to be assessed and reported annually by each European Union member state, taking into consideration European air quality standards. Plans and programmes should be implemented in zones and agglomerations where pollutant concentrations exceed the limit and target values. The main objective of this study is to perform a long-term air quality simulation for Portugal, using the CHIMERE chemistry-transport mod...

  18. Iron-Air Rechargeable Battery

    Science.gov (United States)

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

    2014-01-01

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

  19. Shock-swallowing air sensor

    Science.gov (United States)

    Nugent, J.; Sakamoto, G. M.; Webb, L. D.; Couch, L. M.

    1979-01-01

    An air-data probe allows air to flow through it so that supersonic and hypersonic shock waves form behind pressure measuring orifices and tube instead of directly on them. Measured pressures are close to those in free-flowing air and are used to determine mach numbers of flying aircraft.

  20. Overview of Emerging Air Sensors

    Science.gov (United States)

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

  1. Pupils' Understanding of Air Pollution

    Science.gov (United States)

    Dimitriou, Anastasia; Christidou, Vasilia

    2007-01-01

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

  2. Air Consumption Analysis of Air-Jet Weaving

    Directory of Open Access Journals (Sweden)

    RAJ KUMAR KHIANI

    2016-07-01

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

  3. Enhancing indoor air quality –The air filter advantage

    Directory of Open Access Journals (Sweden)

    Vannan Kandi Vijayan

    2015-01-01

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

  4. Enhancing indoor air quality -The air filter advantage.

    Science.gov (United States)

    Vijayan, Vannan Kandi; Paramesh, Haralappa; Salvi, Sundeep Santosh; Dalal, Alpa Anil Kumar

    2015-01-01

    Air pollution has become the world's single biggest environmental health risk, linked to around 7 million deaths in 2012 according to a recent World Health Organisation (WHO) report. The new data further reveals a stronger link between, indoor and outdoor air pollution exposure and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. The role of air pollution in the development of respiratory diseases, including acute respiratory infections and chronic obstructive pulmonary diseases, is well known. While both indoor and outdoor pollution affect health, recent statistics on the impact of household indoor pollutants (HAP) is alarming. The WHO factsheet on HAP and health states that 3.8 million premature deaths annually - including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer are attributed to exposure to household air pollution. Use of air cleaners and filters are one of the suggested strategies to improve indoor air quality. This review discusses the impact of air pollutants with special focus on indoor air pollutants and the benefits of air filters in improving indoor air quality. PMID:26628762

  5. Laboratory study of air sparging: Air flow visualization

    International Nuclear Information System (INIS)

    Laboratory flow visualization experiments, using glass beads as the porous medium, were conducted to study air sparging, an innovative technology for subsurface contaminant remediation. The purpose of these experiments was to observe how air flows through saturated porous media and to obtain a basic understanding of air plume formation and medium heterogeneity effects. The experiments indicate that air flow occurring in discrete, stable channels is the most probable flow behavior in medium to fine grained water saturated porous media and that medium heterogeneity plays an important role in the development of air channels. Several simulated scales of heterogeneities, from pore to field, have been studied. The results suggest that air channel formation is sensitive to the various scales of heterogeneities. Site-specific hydrogeologic settings have to be carefully reviewed before air sparging is applied to remediate sites contaminated by volatile organic compounds

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

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

  7. Adobe AIR for Android -sovelluskehitys

    OpenAIRE

    Palovuori, Jani

    2011-01-01

    Tässä opinnäytetyössä käsitellään sovelluskehitystä Android-laitteille Adoben AIR for Android -tekniikkaa hyväksi käyttäen. Tavoitteena on esitellä sovelluskehityksen periaatteita Adoben Flash-tekniikkaan pohjautuvan AIR for Android -teknologian kannalta. Työ on tehty Yleisradio Oy:n toimeksiantona ja toimii johdatuksena AIR-sovelluksen kehittämiseen AIR for Android -teknologialla. Työssä esitellään yleisesti rikkaat internet-sovellukset ja käydään tarkemmin läpi Adoben AIR-teknologia sek...

  8. Air Risk Information Support Center

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-31

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-01

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

  10. Control of air toxics

    International Nuclear Information System (INIS)

    For more than 10 years, Argonne National Laboratory has supported the US DOE's Flue Gas Cleanup Program objective by developing new or improved environmental controls for industries that use fossil fuels. Argonne's pollutant emissions research has ranged from experiments in the basic chemistry of pollution-control systems, through laboratory-scale process development and testing, to pilot-scale field tests of several technologies. The work on air toxics is currently divided into two components: Investigating measures to improve the removal of mercury in existing pollution-control systems applied to coal combustion; and, Developing sensors and control techniques for emissions found in the textile industry

  11. In the air

    OpenAIRE

    Andrés López Fernández

    2011-01-01

    RESUMEN En el aire es un viaje a la primera mitad del siglo XX que nos tratará de acercar la frescura y oportunidad de las calles corredor y los jardines en la ciudad vertical. Se inicia en 1909 en Nueva York, con la publicación por la revista Life de La Torre del Globo, se acerca al Inmueble-Villas y al Plan Obus para Argel de Le Corbusier, y finaliza en 1952 con el proyecto para el conjunto residencial de Golden Lane en Londres de A. y P. Smithson. Fragmentos para la ciudad vertical que se ...

  12. 纤维预热温度对真空气压浸渗连续SiC f/Al复合材料致密度和力学性能的影响%Effects of fiber preheating temperature on density and mechanical properties of continuous SiC f/Al composites manufactured by vacuum pressure infiltration

    Institute of Scientific and Technical Information of China (English)

    廖焕文; 徐志锋; 余欢; 王振军

    2014-01-01

    选用先驱体法制备的直径10~15μm束丝SiC纤维作为增强体材料,采用真空气压浸渗法制备了SiC f体积分数为40%的连续SiC f/Al复合材料,研究纤维预热温度对复合材料显微组织与力学性能的影响。结果表明:复合材料中原局部存在少量团聚的SiC纤维束随着纤维预热温度的提高,纤维团聚减少,分布更趋于均匀;而复合材料致密度和抗拉强度随纤维预热温度的升高先逐渐增加后缓慢降低;其中,在纤维预热温度为500℃、浸渗温度为730℃、浸渗压力为7 MPa和保压时间为5 min的浸渗工艺条件下所制备的连续SiC f/Al复合材料的致密度为97.24%,抗拉强度达到768.9 MPa。%The vacuum pressure infiltration was performed for the continuous SiCf/Al composites with the volume fraction of SiC f being 40%, of which the reinforced material is SiC fiber with the diameter of 10-15μm fabricated by precursor method. The effects of fiber preheating temperature on the microstructure and mechanical properties of continuous SiCf/Al composites were studied. The results show that the distribution of the partial fiber reunited in the composite tends to be more uniform, while the density and tensile strength increase first and then reduce with increasing the fiber preheating temperature. Moreover, the density and tensile strength of the continuous SiCf/Al composites increase up to 97.24%and 768.9 MPa when the preheating temperature, infiltration temperature, impregnation pressure and dwell time of the fiber are set as 500℃, 730℃, 7 MPa and 5 min, respectively.

  13. Building air exhaustion device

    International Nuclear Information System (INIS)

    An opening is formed on the side wall of a building such as of a nuclear power plant, and a blow out panel is held (supported) by a clip for closing the opening. A large-diameter pipeline is connected at one end to the opening so as to cover the blow out panel, and immersed at the other end in a pool water. When a pipeline such as of main steam pipelines is ruptured in the building, high temperature and high pressure coolants are flown out from the ruptured port, and the pressure in the building is elevated. The blow out panel falls off from the side of the building by the elevation of the pressure in the building. Steams or compressed air discharged from the opening is introduced to the pool through the large diameter pipeline, then the steams are condensed by the pool water and radioactive materials contained in the condensed steams are kept in the pool water. Radioactive materials contained in the released compression air are also removed into the pool water. (I.N.)

  14. Baltimore Air Toxics Study (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D.A. [Sullivan Environmental Consulting, Inc., Alexandria, VA (United States)

    1996-12-31

    The Baltimore Air Toxics Study is one of the three urban air toxics initiatives funded by EPA to support the development of the national air toxics strategy. As part of this project, the Air Quality Integrated Management System (AIMS) is under development. AIMS is designed to bring together the key components of urban air quality management into an integrated system, including emissions assessment, air quality modeling, and air quality monitoring. Urban area source emissions are computed for a wide range of pollutants and source categories, and are joined with existing point source emissions data. Measured air quality data are used to evaluate the adequacy of the emissions data and model treatments as a function of season, meteorological parameters, and daytime/nighttime conditions. Based on tested model performance, AIMS provides the potential to improve the ability to predict air quality benefits of alternative control options for criteria and toxic air pollutants. This paper describes the methods used to develop AIMS, and provides examples from its application in the Baltimore metropolitan area. The use of AIMS in the future to enhance environmental management of major industrial facilities also will be addressed in the paper.

  15. Comparison of indoor air and outdoor air contaminant concentrations

    OpenAIRE

    Pykhova, Ekaterina

    2014-01-01

    Since most people spend their time indoors, there has been increased interest in air pollution concen-trations. Number of very small liquid and solid particles suspended in the air is depending on different factors. But how should be decreased particle number? The field of this work is particulate matter concentration in the indoor and outdoor air. Measurements were carried out in number concentration. The Indoor-Outdoor correlation was de-termined in order to investigate normative parti...

  16. Nitrogen fluorescence in air for observing extensive air showers

    Directory of Open Access Journals (Sweden)

    Tsunesada Y.

    2013-06-01

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

  17. Sights from the air

    Science.gov (United States)

    Tartara, P.

    2009-04-01

    The first aerial shots were taken by aerostat balloon during the second half of the nineteen century for military purpose and subsequently utilized for civilian, archaeological and town planning uses (Roman Forum 1900, Pompei 1910, Venezia 1913, etc.). Sights from the air have given the most objective representation of the landscape and traces progressively left by human activities. After the First World War the use of airplanes for photogrammetric shots suitable to create cartography (territorial map making) has permitted to realize a good basic documentation; successively it has been increased by aerial reconnaissance during the Second World War. Aerial shots by RAF, USAF and Luftwaffe brought to the establishment of rich aerial photograph Archives, particularly in Europe, which have had a very low utilization for the historical restoration of landscape. From the fifties, aerial documentation becomes systematic for different scale analysis and territorial planning. The use of satellite imagery and multispectral bands integrates the historical and recent aerial photographs; the former is particularly helpful for cartography updating, for large scale environmental analysis, for study and research of territories with not available air photographs or lacking in aerial shots. The amount and density of archaeological buried evidences, unknown at the most, is very substantial in Italy and in the whole Mediterranean area; here air-photo interpretation is being applied at advanced levels, but not systematically, since several decades. Some archaeological research teams, working for the knowledge of territorial cultural heritage, utilize historical and recent aerial photographs intensively (aerial photographs previous the II WW, just before the intensive and extensive use of mechanical means to till the land, preserve a large amount of traces or cropmarks of buried evidences; recent shots taken on different conditions of climate and crops, allow to see and read important

  18. Air climate health

    International Nuclear Information System (INIS)

    'France Nature Environnement Ile de France' publishes, on occasion of the COP 21, a special paper about the air pollution in the Paris region, greenhouse gases and their influence on the environment. This document has been written in close cooperation with professionals and civil associations. Elected representatives from local and regional authorities also speak about their experiences. The first part emphasizes the urgency to accelerate preventive and corrective measures since the air pollution, after slightly decreasing in the 2000's, remains stable. Our work is a science based analysis of essential parameters and details the impact of local pollution and greenhouse gases on the climate. It is based on the GIEC 2013 and 2015 reports, as well as the work of National meteorology in association with the Climate agency of Paris. The threshold of not exceeding an average temperature of +2 deg. C in 2100 is almost reached. If consumption of fossil energies does not heavily decline in the next 10 years, the earth's thermal machine will enter, for several centuries, into an uncontrollable cycle which could endanger life on earth with average temperatures exceeding 4 to 6 deg. C above the current level. The second part reveals the impact of air pollution on the health of the Paris region's population, especially on women who are the most affected by respiratory diseases: obstructive pulmonary bronchitis and asthma. Four departments are particularly affected: Paris, Seine-et-Marne, Seine-Saint-Denis and Val-d'Oise. Even though we do not have the formal causal proof between gas concentration and disease, analysis of similar situations worldwide eliminate any doubts about the reality of the relationship. The third part proposes solutions which can be implemented by local government, companies, but also civil associations and citizens in order to quickly decrease greenhouse gas production. Solutions range from energy sobriety to change in travel

  19. Air Quality and Climate Change

    International Nuclear Information System (INIS)

    Climate change and air quality are closely related: through the policy measures implemented to mitigate these major environmental threats but also through the geophysical processes that drive them. We designed, developed and implemented a comprehensive regional air quality and climate modeling System to investigate future air quality in Europe taking into account the combined pressure of future climate change and long range transport. Using the prospective scenarios of the last generation of pathways for both climate change (emissions of well mixed greenhouse gases) and air pollutants, we can provide a quantitative view into the possible future air quality in Europe. We find that ozone pollution will decrease substantially under the most stringent scenario but the efforts of the air quality legislation will be adversely compensated by the penalty of global warming and long range transport for the business as usual scenario. For particulate matter, the projected reduction of emissions efficiently reduces exposure levels. (authors)

  20. Air ions and aerosol science

    Science.gov (United States)

    Tammet, Hannes

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4-1.8 nm.

  1. Air ions and aerosol science

    Energy Technology Data Exchange (ETDEWEB)

    Tammet, H. [Department of Environmental Physics, Tartu University, Tartu, Estonia (Estonia) 2400

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4{endash}1.8 nm. {copyright} {ital 1996 American Institute of Physics.}

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

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.

    2002-07-01

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

  3. The weight of air

    International Nuclear Information System (INIS)

    Once a controversial idea, the fact that gases like air have weight can easily be demonstrated using reasonably precise scales in the modern teaching laboratory. But unlike a liquid, where a mechanical model suggests a pile of hard spheres resting on each other, gas molecules are in continual motion and can have minimal interaction. How should we think about the effect these molecules have on the scale? And more importantly, how should we explain it to students? Several models of gas behavior are employed to answer these questions and it is shown how the weight of a gas is, like electric current, an emergent phenomena in contrast to the weight of a liquid which is direct or causal. (paper)

  4. Photochemical air pollution syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Hamming, W.J.; MacBeth, W.C.; Chass, R.L.

    1967-01-01

    There are two distinct pollution problems in the Los Angeles Basin - one in winter, the other most frequently in summer and fall. In winter the concentrations of carbon monoxide, nitrogen oxides, sulfur dioxide and black filterable aerosols are higher than in summer, but the secondary pollutants such as ozone and photochemical oxidants are not as high. The photochemical air pollution syndrome is due to a pattern set by previous smog attacks. This pattern is due to low wind speeds, low inversion heights, a trajectory to carry the pollution and sufficient sunlight to photodissociate the nitrogen dioxide formed and to form nitric oxide and atomic oxygen. The results are high levels of oxidant or ozone and large quantities of particles. 5 references, 9 figures, 7 tables.

  5. Change in the air

    International Nuclear Information System (INIS)

    Aviation has a key part to play in the future protection of the environment. Such issues as climate change raise serious questions for all of us, but particularly for energy-intensive industries such as aviation, which makes a small but identifiable contribution to man's impact on the global climate. Airlines, such as British Airways, must strive to meet ever-higher standards of environmental performance. Environmental challenges facing the aviation industry are categorized as: noise, emissions and fuel efficiency, waste of energy, water and material, congestion in the air and on the ground, tourism and conservation. These headings have proved to be robust and our environmental programmes have, accordingly, been deployed under them

  6. metropolitana en Buenos Aires

    Directory of Open Access Journals (Sweden)

    Pedro Pírez

    2006-01-01

    Full Text Available In this paper, we present a description of some concrete processes that made up the transformations in the metropolitan configuration and functioning in Buenos Aires in the 1990s during the 20th Century. We are referring to components related to the impact of processes at the macro level (national and international pertaining to restructuring and globalisation. We aim to understand the “forces” that mediate between the global and the local arenas, identifying the actors and the relationships behind metropolitan changes as well as searching for the meaning that the city acquires and which is understood as “privatisation”. In the first section of the paper, this concept is made explicit.

  7. de Buenos Aires

    Directory of Open Access Journals (Sweden)

    Joaquín Linne

    2014-01-01

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

  8. Preheated shock experiments in the molten CaAl_2Si_2O_8-CaFeSi_2O_6-CaMgSi_2O_6 ternary: A test for linear mixing of liquid volumes at high pressure and temperature

    OpenAIRE

    Thomas, Claire W.; Asimow, Paul D.

    2013-01-01

    We performed 17 new shock wave experiments on preheated (1673 K) hedenbergite liquid (CaFeSi_2O_6) and two model basalt liquids (an equimolar binary mix of CaAl_2Si_2O_8 + CaFeSi_2O_6 and an equimolar ternary mix of CaAl_2Si_2O_8 + CaFeSi_2O_6 +CaMgSi_2O_6) in order to determine their equations of state (EOS). Ambient pressure density measurements on these and other Fe-bearing silicate liquids indicate that FeO has a partial molar volume that is highly dependent on composition, which leads to...

  9. Metal hydride air conditioner

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  10. Atmospheric Chemistry and Air Pollution

    OpenAIRE

    Gaffney, Jeffrey S.; Marley, Nancy A.

    2003-01-01

    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...

  11. Air and metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  12. Air pollution control in practice

    International Nuclear Information System (INIS)

    The book offers a comprehensive treatment of the subject, from air pollution monitoring and effects on human and animal health, on plants and materials, to pollution reduction measures, practical applications, and legal regulations. It intends to give the air pollution expert a basis for developing practicable solutions. Apart from the 'classic' pollutants, also radioactive air pollution is gone into. (DG) With 366 figs., 190 tabs

  13. Managing Air in Olympic Cities

    Directory of Open Access Journals (Sweden)

    Qing W. Tian

    2008-01-01

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

  14. Air pollution: Impact and prevention

    OpenAIRE

    SIERRA-VARGAS, MARTHA PATRICIA; Teran, Luis M.

    2012-01-01

    ABSTRACT Air pollution is becoming a major health problem that affects millions of people worldwide. In support of this observation, the World Health Organization estimates that every year, 2.4 million people die because of the effects of air pollution on health. Mitigation strategies such as changes in diesel engine technology could result in fewer premature mortalities, as suggested by the US Environmental Protection Agency. This review: (i) discusses the impact of air pollution on respirat...

  15. Heat transfer enhancement using air-atomized spray cooling with water-Al2O3 nano-fluid

    International Nuclear Information System (INIS)

    The study deals with the air-atomized spray cooling using nano-fluid as the cooling media for high heat flux applications. The nano-fluid has been prepared by commercial Al2O3 particles of diameter less than 13 nm and water. Heat transfer study has been carried out on a pre-heated steel specimen of dimensions 100 mm x 100 mm x 6 mm. The initial temperature of the plate which was subjected to air-atomized spray cooling was over 900 deg. C. Various coolants consisting of 0.1% volumetric concentration of water -Al2O3 mixture, with or without a dispersing agent (surfactant) were used for the study. The dispersing agents used are sodium dodecyl sulphate (SDS) and polyoxyethylene (20) sorbitan monolaurate (Tween 20). Inverse heat conduction software INTEMP has been used for estimating the surface heat flux and temperatures taking into account the measured internal temperature histories by the thermocouples during the cooling process. The results obtained using nano-fluid coolants are compared with that of the results where pure water (filtered potable water) is used as a coolant. The analyses reveal that the cooling rate, critical heat flux and heat transfer coefficients are significantly enhanced when nano-fluids are used as coolants in air-atomized spray process. Also, the nano-fluid coolants with dispersing agent shows a better enhancement of heat transfer over that of the nano-fluid without the dispersing media. The nano-fluid with dispersing agent Tween 20 is found more effective than that of its counterpart. Overall, the percentage enhancement in cooling rate of all these nano-fluids compared with pure water (filtered potable water) is 10.2% for water-Al2O3, 18.6% for water-Al2O3-SDS, and up to 32.3% for water-Al2O3 -Tween 20. (authors)

  16. "Air embolism during fontan operation"

    Directory of Open Access Journals (Sweden)

    Madan Mohan Maddali

    2014-01-01

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

  17. Managing Air in Olympic Cities

    OpenAIRE

    Qing W. Tian; Peter Brimblecombe

    2008-01-01

    The 21st century Olympic Agenda aims to align itself with the concept of sustainable development and has driven improved environmental quality in host cities, such as the Green Games in Sydney 2000 and the planned Beijing 2008 Games and in London 2012 as the Low Carbon Games. Air quality has long been a concern of Olympic mega-cities, although the air quality plans and strategies have often seemed short-lived and unsustainable in the long term. We have explored air quality data and air pollut...

  18. Effect of Air Outlet Angle on Air Distribution Performance Index

    Directory of Open Access Journals (Sweden)

    Isbeyeh W. Maid

    2013-05-01

    Full Text Available       In this paper a numerical study of velocity and temperature distribution in air conditioned space have been made. The computational model consists of the non-isothermal 3-D turbulent with (k-ε model. The numerical study is made to conduct air distribution in a room air-conditioned space with real interior dimensions (6×4×3m and to analyze the effect of changing angle of grille vanes on the flow pattern, velocity, and temperature distribution in the room under a set of different condition, and under a supply air temperature of 16˚C to examine the final result on air distribution performance index (ADPI.The results show a significant effect within the change of supply air angle, the maximum air distribution performance index (ADPI is 52% when air change per hour (ACH is equal to 10 at 16˚C inlet temperature with angle ( 15˚ down, and the minimum value of (ADPI is 20% when ACH is equal to 15 at 16˚C inlet temperature and angle ( degree. 

  19. Norma Primaria de calidad del aire AIR QUALITY STANDARD

    Directory of Open Access Journals (Sweden)

    PATRICIA MATUS C.

    2002-04-01

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

  20. Fundamentals of air pollution. Third edition

    Energy Technology Data Exchange (ETDEWEB)

    Boubel, R.W.; Fox, D.L.; Turner, D.B.; Stern, A.C.

    1994-12-31

    This book presents an overview of air pollution. In Part I, the history of air pollution and the basic concepts involved with air pollution such as sources, scales, definitions are covered. Part II describes how airborne pollutants damage materials, vegetation, animals, and humans. Six fundamental aspects of air pollution are included in the text: The Elements of Air Pollution; The Effects of Air Pollution; Measurement and Monitoring of Air Pollution; Meterology of Air Pollution; regulatory Control of Air Pollution; and Engineering Control of Air Pollution.

  1. Reduced bleed air extraction for DC-10 cabin air conditioning

    Science.gov (United States)

    Newman, W. H.; Viele, M. R.; Hrach, F. J.

    1980-01-01

    It is noted that a significant fuel savings can be achieved by reducing bleed air used for cabin air conditioning. Air in the cabin can be recirculated to maintain comfortable ventilation rates but the quality of the air tends to decrease due to entrainment of smoke and odors. Attention is given to a development system designed and fabricated under the NASA Engine Component Improvement Program to define the recirculation limit for the DC-10. It is shown that with the system, a wide range of bleed air reductions and recirculation rates is possible. A goal of 0.8% fuel savings has been achieved which results from a 50% reduction in bleed extraction from the engine.

  2. 14 CFR 298.52 - Air taxi operations by commuter air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Air taxi operations by commuter air... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS EXEMPTIONS FOR AIR TAXI AND COMMUTER AIR CARRIER OPERATIONS Commuter Air Carrier Authorizations § 298.52 Air taxi operations by commuter air carriers. (a) A...

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

    Science.gov (United States)

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

    2010-05-01

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

  4. Mind Your Indoor Air Quality

    Science.gov (United States)

    Mak, Lily

    2012-01-01

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

  5. The Federal Air Pollution Program.

    Science.gov (United States)

    National Air Pollution Control Administration (DHEW), Washington, DC.

    Described is the Federal air pollution program as it was in 1967. The booklet is divided into these major topics: History of the Federal Program; Research; Assistance to State and Local Governments; Abatement and Prevention of Air Pollution; Control of Motor Vehicle Pollution; Information and Education; and Conclusion. Federal legislation has…

  6. Improved Air-Treatment Canister

    Science.gov (United States)

    Boehm, A. M.

    1982-01-01

    Proposed air-treatment canister integrates a heater-in-tube water evaporator into canister header. Improved design prevents water from condensing and contaminating chemicals that regenerate the air. Heater is evenly spiraled about the inlet header on the canister. Evaporator is brazed to the header.

  7. Complexity in Air Traffic Management

    OpenAIRE

    Delahaye, Daniel; Puechmorel, Stéphane; Dougui, Nour Elhouda

    2009-01-01

    Air traffic Management Requirements : -Insure separation between aircraft. -Avoid costly manoeuvres and optionally optimize trajectories. -Insure trafic organization. Trends : -Separation delegated to aircraft. -Trajectory based air traffic management. -Introduction of decision support tools / automated conflict solvers. Workload : -Related to cognitive processes of human controllers. -Easy/Hard forecasting of conflict occurrence. -Monitoring is a non negligible part of the workload. -Relevan...

  8. A Breath of Fresh Air

    Science.gov (United States)

    Belew, Rachel

    2011-01-01

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

  9. Air movement - good or bad?

    DEFF Research Database (Denmark)

    Toftum, Jørn

    general terms when air movement is desirable and when it is not. At temperatures up to 22-23oC, at sedentary activity and with occupants feeling neutral or cooler there is a risk of air movement being perceived as unacceptable, even at low velocities. In particular, a cool overall thermal sensation...

  10. Ozone as an air pollutant

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    1996-01-01

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

  11. Airborne rotary air separator study

    Science.gov (United States)

    Acharya, A.; Gottzmann, C. F.; Nowobilski, J. J.

    1990-01-01

    Several air breathing propulsion concepts for future earth-to-orbit transport vehicles utilize air collection and enrichment, and subsequent storage of liquid oxygen for later use in the vehicle emission. Work performed during the 1960's established the feasibility of substantially reducing weight and volume of a distillation type air separator system by operating the distillation elements in high 'g' fields obtained by rotating the separator assembly. This contract studied the capability test and hydraulic behavior of a novel structured or ordered distillation packing in a rotating device using air and water. Pressure drop and flood points were measured for different air and water flow rates in gravitational fields of up to 700 g. Behavior of the packing follows the correlations previously derived from tests at normal gravity. The novel ordered packing can take the place of trays in a rotating air separation column with the promise of substantial reduction in pressure drop, volume, and system weight. The results obtained in the program are used to predict design and performance of rotary separators for air collection and enrichment systems of interest for past and present concepts of air breathing propulsion (single or two-stage to orbit) systems.

  12. Vehicles and Particulate Air Pollution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  13. 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

  14. Anisotropy of successive air showers

    Science.gov (United States)

    Ochi, N.; Wada, T.; Yamashita, Y.; Ohashi, A.; Yamamoto, I.; Nakatsuka, T.; Large Area Air Shower (LAAS) Group

    2001-04-01

    We have investigated the anisotropy of successive air shower (SAS) events, which we define as the detection of many air showers within a short time window, using data from six stations of the Large Area Air Shower (LAAS) group. On the criterion of 22 air showers within 20 minutes, five SAS events are found against 1.4 expected from the Poisson distribution in Okayama University station's data. From six stations' data, we find 24 SAS events in total. By plotting them in equatorial coordinates, it is revealed that SAS events are observed more frequently when the Galactic plane is around the zenith. This can be attributed to a hypothetical small flux of ultra-high-energy γ-rays from the direction of the Galactic plane superposed on conventional cosmic rays. If this hypothesis is true, the analytical procedure used here has potential to measure ultra-high-energy γ-ray sources by even small air shower arrays like ours.

  15. Anisotropy of successive air showers

    International Nuclear Information System (INIS)

    We have investigated the anisotropy of successive air shower (SAS) events, which we define as the detection of many air showers within a short time window, using data from six stations of the Large Area Air Shower (LAAS) group. On the criterion of 22 air showers within 20 minutes, five SAS events are found against 1.4 expected from the Poisson distribution in Okayama University station's data. From six stations' data, we find 24 SAS events in total. By plotting them in equatorial coordinates, it is revealed that SAS events are observed more frequently when the Galactic plane is around the zenith. This can be attributed to a hypothetical small flux of ultra-high-energy γ-rays from the direction of the Galactic plane superposed on conventional cosmic rays. If this hypothesis is true, the analytical procedure used here has potential to measure ultra-high-energy γ-ray sources by even small air shower arrays like ours

  16. Air Quality at Your Street

    DEFF Research Database (Denmark)

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

    concerned citizents, or in the context of localization of institutions, etc. The purpose of the project ‘Air Quality at Your Street’ is to create interactive air quality maps on the internet using webGIS to illustrate the geographical variation of air quality in Denmark for selected health related air...... is calculated with a model system consisting of a regional model (DEHM), an urban background model (UBM) and a street model (OSPM) with associated meteorology and emissions data etc. Recently updated input data has been used for the road network and traffic data based on the national traffic model...... (LTM) from DTU Transport as well as data on travel speeds based on GPS data from SpeedMap from the Danish Road Directorate. Modelled concentrations have been compared to fixed regional, urban background and street air quality monitoring stations to assess uncertainties, and to model results from about...

  17. Tritium-in-air monitor

    International Nuclear Information System (INIS)

    A system for continuously monitoring air for the presence of tritiated water vapor is described comprising contacting a predetermined mass flow of an air sample with a predetermined flow of a liquid miscible with tritiated water to transfer any tritiated water vapor in the air sample to the liquid; stripping radioactive noble gases from the liquid with a stream of gas; and analyzing the liquid for beta radiation to determine the presence of tritium. In the preferred embodiment of the apparatus an air-liquid contactor, a gas-liquid separator and a stripper are combined into a single unit with a common outlet for the contacted air and stripping gas. 6 claims, 2 figures

  18. Lithium-Air Cell Development

    Science.gov (United States)

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

    2014-01-01

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

  19. 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.

  20. Population Dynamics and Air Pollution

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  1. Airing Out Anthrax

    Science.gov (United States)

    2002-01-01

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

  2. Air coolant system

    International Nuclear Information System (INIS)

    The main patent relates to a process of cooling the steam from the turbine working with a nuclear power reactor, in said process a two-phase fluid mixture is circulated inside a closed circuit between the turbine condenser and a cooling tower. The present addition to the main patent relates to a cooling system comprising instead of the vertical tower, a nearly horizontal structure open to wind, in which the air is circulated by natural convection. The lower part of said structure, according to the invention, comprises two parallel rows of nearly rectangular cooling fins and the upper part consists of two walls made antiparallel with respect to the longitudinal symmetry plane of said structure and thus forming an upwards widening, the resulting vertical planar section of the long-shaped cooling structure according to the invention assuming a venturi shape. Said type of structure a few hundred meters long but only fifty meters high is less visible in the landscape than the vertical tower, and condensation clouds are formed onside a larger surface, that is another ecological advantage

  3. Breathe the air!

    CERN Multimedia

    2003-01-01

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

  4. Radioxenon spiked air.

    Science.gov (United States)

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

    2015-12-01

    Four of the radioactive xenon isotopes ((131m)Xe, (133m)Xe, (133)Xe and (135)Xe) with half-lives ranging from 9 h to 12 days are produced from nuclear fission and can be detected from days to weeks following their production and release. Being inert gases, they are readily transported through the atmosphere. Sources for release of radioactive xenon isotopes include operating nuclear reactors via leaks in fuel rods, medical isotope production facilities, and nuclear weapons' detonations. They are not normally released from fuel reprocessing due to the short half-lives. The Comprehensive Nuclear-Test-Ban Treaty has led to creation of the International Monitoring System. The International Monitoring System, when fully implemented, will consist of one component with 40 stations monitoring radioactive xenon around the globe. Monitoring these radioactive xenon isotopes is important to the Comprehensive Nuclear-Test-Ban Treaty in determining whether a seismically detected event is or is not a nuclear detonation. A variety of radioactive xenon quality control check standards, quantitatively spiked into various gas matrices, could be used to demonstrate that these stations are operating on the same basis in order to bolster defensibility of data across the International Monitoring System. This paper focuses on Idaho National Laboratory's capability to produce three of the xenon isotopes in pure form and the use of the four xenon isotopes in various combinations to produce radioactive xenon spiked air samples that could be subsequently distributed to participating facilities. PMID:26318775

  5. Air pollution in Copenhagen

    International Nuclear Information System (INIS)

    Aerosols were monitored in Greater Copenhagen in the period June 1973 to July 1974. Size-fractionated cascade impactor samples and unfractionated filter samples were regularly collected and analyzed be neutron activation analysis, spark emission spectroscopy or proton-induced X-ray emission spectroscopy. Concentrations were determined of the following elements: Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Mo, Cd, Sn, Sb, and Pb. All elements showed orders-of-magnitude fluctuationsthe mean concentrations were roughly the same as in other large cities. In relation to proposed air quality standards, Pb was the most critical component. Statistical analysis of variation patterns, size distributions and interelement correlations indicate that automotive exhaust is the source of Br and Pbfuel-oil combustion is the main source of V and Ni (and partly of S)soil dust raised by wind or by human activity (e.g. traffic) is the main source of Al, Si, Ca, Ti, and Fe. (author)

  6. Air contaminants in a submarine equipped with air independent propulsion.

    Science.gov (United States)

    Persson, Ola; Ostberg, Christina; Pagels, Joakim; Sebastian, Aleksandra

    2006-11-01

    The Swedish Navy has operated submarines equipped with air independent propulsion for two decades. This type of submarine can stay submerged for periods far longer than other non-nuclear submarines are capable of. The air quality during longer periods of submersion has so far not been thoroughly investigated. This study presents results for a number of air quality parameters obtained during more than one week of continuous submerged operation. The measured parameters are pressure, temperature, relative humidity, oxygen, carbon dioxide, hydrogen, formaldehyde and other volatile organic compounds, ozone, nitrogen dioxide, particulate matter and microbiological contaminants. The measurements of airborne particles demonstrate that air pollutants typically occur at a low baseline level due to high air exchange rates and efficient air-cleaning devices. However, short-lived peaks with comparatively high concentrations occur, several of the sources for these have been identified. The concentrations of the pollutants measured in this study do not indicate a build-up of hazardous compounds during eight days of submersion. It is reasonable to assume that a substantial build-up of the investigated contaminants is not likely if the submersion period is prolonged several times, which is the case for modern submarines equipped with air independent propulsion. PMID:17075617

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

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.

    2014-09-01

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

  8. Large scale air monitoring: Biological indicators versus air particulate matter

    International Nuclear Information System (INIS)

    Biological indicator organisms are widely used for monitoring and banking purposes since many years. Although the complexity of the interactions between bioorganisms and their environment is generally not easily comprehensible, environmental quality assessment using the bioindicator approach offers some convincing advantages compared to direct analysis of soil, water, or air. Direct measurement of air particulates is restricted to experienced laboratories with access to expensive sampling equipment. Additionally, the amount of material collected generally is just enough for one determination per sampling and no multidimensional characterization might be possible. Further, fluctuations in air masses have a pronounced effect on the results from air filter sampling. Combining the integrating property of bioindicators with the world wide availability and uniform matrix characteristics of air particulates as a prerequisite for global monitoring of air pollution will be discussed. A new approach for sampling urban dust using large volume filtering devices installed in air conditioners of large hotel buildings is assessed. A first experiment was initiated to collect air particulates (300 to 500 g each) from a number of hotels during a period of three to four months by successive vacuum cleaning of used inlet filters from high volume air conditioning installations reflecting average concentrations per three months in different large cities. This approach is expected to be upgraded and applied for global monitoring. Highly positive correlated elements were found in lichen such as K/S, Zn/P, the rare earth elements (REE) and a significant negative correlation between Fig and Cu was observed in these samples. The ratio of concentrations of elements in dust and Usnea spp. is highest for Cr, Zn, and Fe (400-200) and lowest for elements such as Ca, Rb, and Sr (20-10). (author)

  9. Large scale air monitoring: lichen vs. air particulate matter analysis.

    Science.gov (United States)

    Rossbach, M; Jayasekera, R; Kniewald, G; Thang, N H

    1999-07-15

    Biological indicator organisms have been widely used for monitoring and banking purposes for many years. Although the complexity of the interactions between organisms and their environment is generally not easily comprehensible, environmental quality assessment using the bioindicator approach offers some convincing advantages compared to direct analysis of soil, water, or air. Measurement of air particulates is restricted to experienced laboratories with access to expensive sampling equipment. Additionally, the amount of material collected generally is just enough for one determination per sampling and no multidimensional characterization might be possible. Further, fluctuations in air masses have a pronounced effect on the results from air filter sampling. Combining the integrating property of bioindicators with the world wide availability and particular matrix characteristics of air particulate matter as a prerequisite for global monitoring of air pollution is discussed. A new approach for sampling urban dust using large volume filtering devices installed in air conditioners of large hotel buildings is assessed. A first experiment was initiated to collect air particulates (300-500 g each) from a number of hotels during a period of 3-4 months by successive vacuum cleaning of used inlet filters from high volume air conditioning installations reflecting average concentrations per 3 months in different large cities. This approach is expected to be upgraded and applied for global monitoring. Highly positive correlated elements were found in lichens such as K/S, Zn/P, the rare earth elements (REE) and a significant negative correlation between Hg and Cu was observed in these samples. The ratio of concentrations of elements in dust and Usnea spp. is highest for Cz, Zn and Fe (400-200) and lowest for elements such as Ca, Rb, and Sr (20-10). PMID:10474261

  10. Air Pollution in the World's Megacities.

    Science.gov (United States)

    Richman, Barbara T., Ed.

    1994-01-01

    Reports findings of the Global Environment Monitoring System study concerning air pollution in the world's megacities. Discusses sources of air pollution, air pollution impacts, air quality monitoring, air quality trends, and control strategies. Provides profiles of the problem in Beijing, Los Angeles, Mexico City, India, Cairo, Sao Paulo, and…

  11. Egypt air radioactive sources warehouse

    International Nuclear Information System (INIS)

    I would like to give me this chance, of being here among famous scientists. I wish to thank the general director of cargo division, and the general manager of import for providing all facilities for me to be present at this scientific meeting. At this conference, I wish to explain the role played by egypt air (as public sector company) in the officiant of radiation physics. The atomic energy authority, ministry of health, and ministry of civil aviation; have provided instructions that were essentially required to complete the work of the national radioactive warehouse located in egypt air terminal in Cairo. Now the license for operating the store has been granted. Prior to constructing the warehouse, the radioactive sources were distributed among the foreign cargo terminals at Cairo airport, such as swiss air, air france, saudi arabia, the Ice stores, as well egypt Air. Cargo terminals. The control of radiation hazard was therefore difficult. The ministry of Civil aviation then issued a decree dictating the storage of all radioactive sources exclusively at the national store of egypt air. All foreign cargo terminals should transfer all imported radioactive sources to the national warehouse at Cairo air port. According to that decree. 6 figs, 2 tabs

  12. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2010-12-01

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

  14. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    Energy Technology Data Exchange (ETDEWEB)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O [Laboratoire EM2C, CNRS UPR288, Ecole Centrale Paris, 92295 Chatenay-Malabry (France)

    2010-12-15

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N{sub 2} (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10{sup 15} cm{sup -3} towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10{sup 11} cm{sup -3} produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10{sup 8} cm{sup -3}.

  15. Air Force neutron dosimetry program

    International Nuclear Information System (INIS)

    Approximately 1000 Air Force personnel are monitored for neutron radiation resulting from various sources at more than thirty worldwide locations. Neutron radiation spanning several orders of magnitude in energy is encountered. The Air Force currently uses albedo thermoluminescent neutron dosimeters for personnel monitoring. The energy dependence of the albedo neutron dosimeter is a current problem and the development of site specific correction factors is ongoing. A summary of data on the energy dependence is presented as well as efforts to develop algorithms for the dosimeter. An overview of current Air Force neutron dosimetry users and needs is also presented

  16. Korean Air Excellence in Flight

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

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

  17. Local air entrainment and detrainment

    OpenAIRE

    Kobus, Helmut

    1984-01-01

    Air and water are usually well separated by gravity due to their extreme difference in specific weight. Whenever they are mixed, however, they give rise to a very complex two-phase flow situation. The hydraulic engineer is often faced with the problem of estimating the effects of entrained air upon the flow, because this may be essential for the safe operation of a hydraulic structure.The predominant mechanism in generating airwater mixtures is the inclusion of air at the surface of flowing w...

  18. Air quality indices : a review

    International Nuclear Information System (INIS)

    Pollution Probe presents some background information that will help in the development of a national Air Quality Index (AQI) in Canada. This report examines the issues that should be addressed in revising the national Index of the Quality of Air (IQUA) or creating a new national Air Quality Index. The IQUA was devised in 1976 and provides Canadians with real-time information on the state of community air quality by including major pollutants and their synergies. It is currently being used for air quality management plans and air quality alert systems. At the same time that the IQUA was devised, the United States Environmental Protection Agency (US EPA) produced a parallel air quality index known as the Pollution Standard Index (PSI) which incorporated 5 criteria pollutants (particulate matter, sulphur dioxide, carbon monoxide, nitrogen oxide and ground level ozone) for which national health-based standards were devised. In 1999, the US EPA renamed their index the Air Quality Index (AQI) and made revisions to the primary health-based national ambient air quality standards for ground-level ozone and particulate matter. Separate values for PM2.5 and PM10 were incorporated and mandatory reporting was required for metropolitan areas with populations of 350,000 or more. Similarly, the IQUA has undergone major developments that affect the validity of the index, including: rejection by the Working Group on Air Quality Objectives and Guidelines of the previous maximum desirable and maximum acceptable air quality criteria, recognition that standards for many of the contaminants are outdated, developing more sensitive instrumentation for real-time monitoring of contaminants. This report also describes the use of the national short term Air Quality Index by provincial, territorial and local authorities in Canada. Pollution Probe recommends setting up a mechanism to review and revise IQUA on a regular basis that would incorporate governments, the medical profession, special

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Tiax Llc

    2006-02-28

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

  1. Air Conditioning Compressor Air Leak Detection by Image Processing Techniques for Industrial Applications

    OpenAIRE

    Pookongchai Kritsada; Nakornrat Prasit; Sookananta Bongkoj; Buasri Panhathai

    2015-01-01

    This paper presents method to detect air leakage of an air conditioning compressor using image processing techniques. Quality of air conditioning compressor should not have air leakage. To test an air conditioning compressor leak, air is pumped into a compressor and then submerged into the water tank. If air bubble occurs at surface of the air conditioning compressor, that leakage compressor must be returned for maintenance. In this work a new method to detect leakage and search leakage point...

  2. Historical Ambient Air Quality Data Inventory

    Data.gov (United States)

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

  3. High Altitude Clear Air Turbulence Project

    Data.gov (United States)

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

  4. National Air Toxic Assessments (NATA) Results

    Data.gov (United States)

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

  5. Clean Air Status and Trends Network (CASTNET)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Clean Air Status and Trends Network (CASTNET) is a national air quality monitoring network designed to provide data to assess trends in air quality, atmospheric...

  6. Profit goal set for airBaltic

    Index Scriptorium Estoniae

    2011-01-01

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

  7. Manual on indoor air quality

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, R.C.; Grimsrud, D.T.

    1983-12-01

    This reference manual was prepared to assist electric utilities in helping homeowners, builders, and new home buyers to understand a broad range of issues related to indoor air quality. The manual is directed to technically knowledgeable persons employed by utility companies - the customer service or marketing representative, applications engineer, or technician - who may not have specific expertise in indoor air quality issues. In addition to providing monitoring and control techniques, the manual summarizes the link between pollutant concentrations, air exchange, and energy conservation and describes the characteristics and health effects of selected pollutants. Where technical information is too lengthy or complex for inclusion in this volume, reference sources are given. Information for this manual was gathered from technical studies, manufacturers' information, and other materials from professional societies, institutes, and associations. The aim has been to provide objective technical and descriptive information that can be used by utility personnel to make informed decisions about indoor air quality issues.

  8. 2011 NATA - Air Toxics Monitors

    Data.gov (United States)

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

  9. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

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

  10. A Martian Air Battery Project

    Data.gov (United States)

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

  11. Personal Air Vehicle Research Project

    Data.gov (United States)

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

  12. US Air Force Balloon Observations

    Data.gov (United States)

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

  13. Kongres IFLA v Buenos Aires

    Czech Academy of Sciences Publication Activity Database

    Burgetová, Jarmila

    -, č. 4 (2004), s. 4-7. ISSN 1210-8502 Keywords : IFLA * International Federation of Library Associations and Institutions * Congress 2004 * Buenos Aires Subject RIV: AF - Documentation, Librarianship, Information Studies

  14. Indoor plants as air cleaners

    DEFF Research Database (Denmark)

    Dela Cruz, Majbrit; Christensen, Jan H.; Müller, Renate

    2015-01-01

    experiments is not directly transferrable to real life settings. The largest problem is the use of closed chambers where there is no air exchange. This also results in a declining VOC concentration over time. Due to this limitation, we constructed a new experimental system which among others can allow for air......Plants have been used decoratively indoors for centuries. For the last 25-30 years, their beneficial abilities to reduce the levels of harmful volatile organic compounds (VOCs) from the indoor air have also been investigated. Previous studies have shown that VOCs are removed by the plant itself...... exchange and a constant VOC concentration. With the new system it was found that removal rates obtained in chambers with air exchange and constant VOC concentration were significantly higher than removal rates obtained in closed chambers. This means that removal rates obtained in closed chambers may be an...

  15. In Brief: Air pollution app

    Science.gov (United States)

    Showstack, Randy

    2010-10-01

    A new smartphone application takes advantage of various technological capabilities and sensors to help users monitor air quality. Tapping into smartphone cameras, Global Positioning System (GPS) sensors, compasses, and accelerometers, computer scientists with the University of Southern California's (USC) Viterbi School of Engineering have developed a new application, provisionally entitled “Visibility.” Currently available for the Android telephone operating system, the application is available for free download at http://robotics.usc.edu/˜mobilesensing/Projects/AirVisibilityMonitoring. An iPhone application may be introduced soon. Smartphone users can take a picture of the sky and then compare it with models of sky luminance to estimate visibility. While conventional air pollution monitors are costly and thinly deployed in some areas, the smartphone application potentially could help fill in some blanks in existing air pollution maps, according to USC computer science professor Gaurav Sukhatme.

  16. Manual on indoor air quality

    International Nuclear Information System (INIS)

    This reference manual was prepared to assist electric utilities in helping homeowners, builders, and new home buyers to understand a broad range of issues related to indoor air quality. The manual is directed to technically knowledgeable persons employed by utility companies - the customer service or marketing representative, applications engineer, or technician - who may not have specific expertise in indoor air quality issues. In addition to providing monitoring and control techniques, the manual summarizes the link between pollutant concentrations, air exchange, and energy conservation and describes the characteristics and health effects of selected pollutants. Where technical information is too lengthy or complex for inclusion in this volume, reference sources are given. Information for this manual was gathered from technical studies, manufacturers' information, and other materials from professional societies, institutes, and associations. The aim has been to provide objective technical and descriptive information that can be used by utility personnel to make informed decisions about indoor air quality issues

  17. US Air Force Base Observations

    Data.gov (United States)

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

  18. Air pollution in the Slovak Republic, 2001

    International Nuclear Information System (INIS)

    A report on air quality and contribution of individual sources on its pollution in the Slovak Republic in 2001 is presented. This report consists of two parts: (1) Ambient air and (2) Emission. Ambient air part is divided into the following chapters: Regional air pollution and quality of precipitation; Local air pollution; Atmospheric ozone. Emission part is divided into the following chapters: Emission and air pollution source inventory, Greenhouse gas emissions

  19. Senyawa Organik Dalam Air Minum

    Directory of Open Access Journals (Sweden)

    Sri Soewasti Soesanto

    2012-09-01

    Full Text Available Kadar zat   organik   yang berlebihan dalam  air  minum  tidak diperbolehkan karena selain menimbulkan warna, bau dan  rasa yang tidak  diinginkan, juga mungkin bersifat toksik baik secara langsung maupun setelah bersenyawa dengan zat lain yang ada.Zat organik yang ada dalam air minum dapat berasal dari alam atau sebagai dampak dari kegiatan manusia.

  20. Molecular Epidemiology and Air Pollution

    Czech Academy of Sciences Publication Activity Database

    Rössner ml., Pavel; Binková, B.; Rössnerová, Andrea; Šrám, Radim

    Rieka: InTech, 2015 - (Nejadkoorki, F.), s. 609-643 ISBN 978-953-51-2180-0 R&D Projects: GA ČR GA13-13458S Institutional support: RVO:68378041 Keywords : molecular epidemiology * biomarkers * human populations * in vitro studies Subject RIV: DN - Health Impact of the Environment Quality http://www.intechopen.com/books/current-air-quality-issues/molecular-epidemiology-and-air- pollution