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

International Nuclear Information System (INIS)

Sandor, P.; Soroka, B.; Kudryavtsev, V.; Zgurskyy, V.

2009-01-01

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)

Experimental study of a single fuel jet in conditions of highly preheated air combustion

Energy Technology Data Exchange (ETDEWEB)

Lille, Simon; Blasiak, W. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy

2000-04-01

Highly Preheated Air Combustion (HPAC) is a technique to reduce consumption of fuel and decrease NO{sub x} formation in furnaces. The main change that occur in the furnace chamber is that the flow pattern of flue gases changes dramatically resulting in a more uniform heat transfer. The usefulness of regenerative combustion is very clear, but the advantages have so far been accompanied by high levels of pollutants, such as NO{sub x}. The combination of the regeneration technique and internal flue gas recirculation, thus decreasing NO{sub x} and keeping the other advantages, has made HPAC a very attractive combustion technology with application to heat treatment reheating and melting processes. This work gives an introduction to regenerative combustion with diluted air, including theory on flame stabilization. Furthermore, a description of a new test furnace is given with results from a parametric study and from tests using schlieren color visualization, direct photography, and laser Doppler anemometry. In the parametric study NO{sub x}-emission, CO-emission, lift-off, fluctuations, and some flame characteristics are related to nozzle diameter, oxygen concentration, and preheat temperature. For the schlieren technique and direct photography, both still and high-speed cameras were used.

Behavior of the turbine - regenerating preheaters functional assembly

International Nuclear Information System (INIS)

Bigu, Melania; Nita, Iulian Pavel; Tenescu, Mircea

2004-01-01

In the classical calculation of pressure distribution in the turbine-regenerating heaters' assembly a uniform distribution of feedwater enthalpy rise at each regenerating preheating step is usually assumed. This is accurately enough as a basis of designing of the preheating installation operating at rated power regime. But at partial regimes this is not totally valid since the preheaters are already shaped and the quasi-equal distribution does not satisfy the equation system describing the heat transfer correlations in these installations. A more detailed analysis shows that pressure in the feeding line preheaters and the bleeding steam flow rates at the turbine outlets are described physically by solving simultaneously the equations of hydrodynamic flow through the turbine and the equations of the heat transfer in the preheaters of the feedwater preheating line. This work approaches this more accurate solving method at least from a theoretical standing point; two cases are illustrated in the annexes of the work: a case of a secondary circuit with a single regenerating inlet and a case with two regenerating inlets. A classical - Panzer method of transformation of a many regenerative stages scheme may lead to one or another of the above cases. (authors)

Susceptibility of CANDU steam generator preheater to cavitation erosion

International Nuclear Information System (INIS)

Laroche, S.L.; Sun, L.; Pietralik, J.M.

2012-01-01

In 2009, Darlington Steam Generator (SG) tube inspections revealed some tubes had degraded in the preheater. The tube degradation occurred at the clearance gap between the tube and the preheater baffle and reached up to 50% through-wall depth at the baffles in the middle portion of the preheater. The general pattern of the damage and the elemental composition analysis suggested that the degradation was the result of a hydrodynamic process, such as cavitation erosion. Cavitation erosion occurs when vapour bubbles exist or form in the flowing liquid and then these bubbles collapse violently in the vicinity of the wall. These bubbles collapse when steam bubbles contact water that is sufficiently subcooled, below the saturation temperature. In the gap between the tube and the preheater baffle, low flow will exist due to the pressure difference across the baffle plate. In addition, heat transfer occurs from the primary-side fluid to the secondary-side fluid within this clearance gap that is driven by the primary-to-secondary temperature difference. Factors, such as the tube position in the baffle hole and fouling, influence the local conditions and can cause subcooled boiling that result in cavitation. This paper presents a study of flow and heat transfer phenomena to determine the factors contributing to cavitation erosion in SG preheaters. The analysis used the THIRST1 code for a 3-dimensional thermalhydraulic simulation of the steam generators and the ANSYS FLUENT®2 code for detailed calculations of flow and heat transfer in the clearance gaps. This study identifies that tubes in the preheater region are susceptible to cavitation erosion and indicates that this area should be part of the station inspection program because, regardless of preheater design, some tubes may experience the thermalhydraulic conditions and undergo degradations similar to those observed for the tubes in Darlington SGs. (author)

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

Directory of Open Access Journals (Sweden)

Madan BHOWMICK

2011-01-01

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

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.

Efficiency of the pre-heater against flow rate on primary the beta test loop

International Nuclear Information System (INIS)

Edy Sumarno; Kiswanta; Bambang Heru; Ainur R; Joko P

2013-01-01

Calculation of efficiency of the pre-heater has been carried out against the flow rate on primary the BETA Test Loop. BETA test loop (UUB) is a facilities of experiments to study the thermal hydraulic phenomenon, especially for thermal hydraulic post-LOCA (Lost of Coolant Accident). Sequences removal on the BETA Test Loop contained a pre-heater that serves as a getter heat from the primary side to the secondary side, determination of efficiency is to compare the incoming heat energy with the energy taken out by a secondary fluid. Characterization is intended to determine the performance of a pre-heater, then used as tool for analysis, and as a reference design experiments. Calculation of efficiency methods performed by operating the pre-heater with fluid flow rate variation on the primary side. Calculation of efficiency on the results obtained that the efficiency change with every change of flow rate, the flow rate is 71.26% on 163.50 ml/s and 60.65% on 850.90 ml/s. Efficiency value can be even greater if the pre-heater tank is wrapped with thermal insulation so there is no heat leakage. (author)

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.

Constraints on variations in inflaton decay rate from modulated preheating

Energy Technology Data Exchange (ETDEWEB)

Mazumdar, Arindam [Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-64 (India); Modak, Kamakshya Prasad, E-mail: arindam.mazumdar@saha.ac.in, E-mail: kamakshya.modak@saha.ac.in [Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-64 (India)

2016-06-01

Modulated (p)reheating is thought to be an alternative mechanism for producing super-horizon curvature perturbations in CMB. But large non-gaussianity and iso-curvature perturbations produced by this mechanism rule out its acceptability as the sole process responsible for generating CMB perturbations. We explore the situation where CMB perturbations are mostly generated by usual quantum fluctuations of inflaton during inflation, but a modulated coupling constant between inflaton and a secondary scalar affects the preheating process and produces some extra curvature perturbations. If the modulating scalar field is considered to be a dark matter candidate, coupling constant between the fields has to be unnaturally fine tuned in order to keep the local-form non-gaussianity and the amplitude of iso-curvature perturbations within observational limit; otherwise parameters of the models have to be tightly constrained. Those constraints imply that the curvature perturbations generated by modulated preheating should be less than 15% of the total observed CMB perturbations. On the other hand if the modulating scalar field is not a dark matter candidate, parameters of the models could not be constrained, but the constraints on the maximum amount of the curvature perturbations coming from modulated preheating remain valid.

Constraints on variations in inflaton decay rate from modulated preheating

International Nuclear Information System (INIS)

Mazumdar, Arindam; Modak, Kamakshya Prasad

2016-01-01

Modulated (p)reheating is thought to be an alternative mechanism for producing super-horizon curvature perturbations in CMB. But large non-gaussianity and iso-curvature perturbations produced by this mechanism rule out its acceptability as the sole process responsible for generating CMB perturbations. We explore the situation where CMB perturbations are mostly generated by usual quantum fluctuations of inflaton during inflation, but a modulated coupling constant between inflaton and a secondary scalar affects the preheating process and produces some extra curvature perturbations. If the modulating scalar field is considered to be a dark matter candidate, coupling constant between the fields has to be unnaturally fine tuned in order to keep the local-form non-gaussianity and the amplitude of iso-curvature perturbations within observational limit; otherwise parameters of the models have to be tightly constrained. Those constraints imply that the curvature perturbations generated by modulated preheating should be less than 15% of the total observed CMB perturbations. On the other hand if the modulating scalar field is not a dark matter candidate, parameters of the models could not be constrained, but the constraints on the maximum amount of the curvature perturbations coming from modulated preheating remain valid.

Metric preheating and limitations of linearized gravity

International Nuclear Information System (INIS)

Bassett, Bruce A.; Tamburini, Fabrizio; Kaiser, David I.; Maartens, Roy

1999-01-01

During the preheating era after inflation, resonant amplification of quantum field fluctuations takes place. Recently it has become clear that this must be accompanied by resonant amplification of scalar metric fluctuations, since the two are united by Einstein's equations. Furthermore, this 'metric preheating' enhances particle production, and leads to gravitational rescattering effects even at linear order. In multi-field models with strong preheating (q>>1), metric perturbations are driven non-linear, with the strongest amplification typically on super-Hubble scales (k→0). This amplification is causal, being due to the super-Hubble coherence of the inflaton condensate, and is accompanied by resonant growth of entropy perturbations. The amplification invalidates the use of the linearized Einstein field equations, irrespective of the amount of fine-tuning of the initial conditions. This has serious implications on all scales - from large-angle cosmic microwave background (CMB) anisotropies to primordial black holes. We investigate the (q,k) parameter space in a two-field model, and introduce the time to non-linearity, t nl , as the timescale for the breakdown of the linearized Einstein equations. t nl is a robust indicator of resonance behavior, showing the fine structure in q and k that one expects from a quasi-Floquet system, and we argue that t nl is a suitable generalization of the static Floquet index in an expanding universe. Backreaction effects are expected to shut down the linear resonances, but cannot remove the existing amplification, which threatens the viability of strong preheating when confronted with the CMB. Mode-mode coupling and turbulence tend to re-establish scale invariance, but this process is limited by causality and for small k the primordial scale invariance of the spectrum may be destroyed. We discuss ways to escape the above conclusions, including secondary phases of inflation and preheating solely to fermions. The exclusion principle

A computer simulation of the transient response of a 4 cylinder Stirling engine with burner and air preheater in a vehicle

Science.gov (United States)

Martini, W. R.

1981-01-01

A series of computer programs are presented with full documentation which simulate the transient behavior of a modern 4 cylinder Siemens arrangement Stirling engine with burner and air preheater. Cold start, cranking, idling, acceleration through 3 gear changes and steady speed operation are simulated. Sample results and complete operating instructions are given. A full source code listing of all programs are included.

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

Directory of Open Access Journals (Sweden)

Xiang Gou

2016-12-01

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

Regenerative heat exchanger for cowper combustion air preheating

Energy Technology Data Exchange (ETDEWEB)

Molenaar, R.; Otterbach, G.

1986-01-13

The waste gas leaving cowper units at a temperature of 200/sup 0/C to 300/sup 0/C was previously discharged unused into the atmosphere. By providing a suitable heat exchanger, the heat content of the waste gas can be used to preheat the combustion agents of cowpers to an extent allowing both to increase the efficiency of cowpers and to decrease the amount of rich gas required. The operating results confirm to a large extent the theoretical assumptions and calculations. One may therefore expect the entire investment to have been fully redeemed in a little more than two years. (orig.).

Gravity mediated preheating

International Nuclear Information System (INIS)

Maity, Debaprasad

2015-01-01

In this work we propose a mechanism of natural preheating of our universe induced by the inflation field dependent effective mass term for the gravitational wave. For any single field inflationary model, the inflation must go through the oscillatory phase after the end of inflation. As has recently been shown, if the gravitational fluctuation has inflation dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflation though parametric resonance. Because of this large enhancement of the amplitude of the gravitational wave, we show that universe can be naturally pre-heated through a minimally coupled matter field with gravity. Therefore, during the pre-heating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflation. (author)

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

Directory of Open Access Journals (Sweden)

Dolianitis Ioannis

2016-01-01

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

Modelling of preheated regenerative chain in Cernavoda NPP using MMS calculation code

International Nuclear Information System (INIS)

Bigu, M.; Nita, I.; Prisecaru, I.; Dupleac, D.

2005-01-01

Full text: In this work it was studied operation of preheated regenerative chain from NPP Cernavoda. To obtain this analysis coupled analyses of condensate system, water supply system, and drain cooler system were effected. The analysis boundaries are: Upstream: - Steam condensers - Turbine Bleed Steam Downstream: - Steam Generators. The analysis was made in two steps: 1) Getting of hydraulic characteristic of pipe network from steam condensers to steam generators at nominal regime; this step was obtained with hydraulic package called PIPENET. 2) Real thermal hydraulic analyses were done based on hydraulic characteristic of pipe network and supplementary data required for heat transfer calculation in equipment of preheated regenerative chain. Thermal analyses were done using MMS package and refered to normal operating regimes, namely, nominal operating regime required for calibration of calculating model, shutdown regime, start-up regime from zero power hot to nominal power and to abnormal operating regimes, namely, turbine trip, reactor trip and loss of two condensate pumps. The results were compared with already existing analysis and showed the largest differences at interface areas (i.e. 5%). This led us to idea of extending analysis to all secondary circuits in order to reduce the number of boundary conditions which can generate uncertainty in analysis. In this analysis we obtained an advanced model of preheated regenerative chain of secondary circuit in Cernavoda NPP which could be extended up to cover the whole secondary circuit by including the analysis of steam generators, turbine, and steam condenser. (authors)

Modelling of preheated regenerative chain in Cernavoda NPP using MMS calculation code

International Nuclear Information System (INIS)

Bigu, M.; Nita, I.; Prisecaru, I.; Dupleac, D.

2005-01-01

In this work it was studied operation of preheated regenerative chain from NPP Cernavoda. To obtain this analysis coupled analyses of condensate system, water supply system, and drain cooler system were effected. The analysis boundaries are: Upstream: - Steam condensers - Turbine Bleed Steam Downstream: - Steam Generators. The analysis was made in two steps: 1) Getting of hydraulic characteristic of pipe network from steam condensers to steam generators at nominal regime; this step was obtained with hydraulic package called PIPENET. 2) Real thermal hydraulic analyses were done based on hydraulic characteristic of pipe network and supplementary data required for heat transfer calculation in equipment of preheated regenerative chain. Thermal analyses were done using MMS package and referred to normal operating regimes, namely, nominal operating regime required for calibration of calculating model, shutdown regime, start-up regime from zero power hot to nominal power and to abnormal operating regimes, namely, turbine trip, reactor trip and loss of two condensate pumps. The results were compared with already existing analysis and showed the largest differences at interface areas (i.e. 5%). This led US to idea of extending analysis to all secondary circuits in order to reduce the number of boundary conditions which can generate uncertainty in analysis. In this analysis we obtained an advanced model of preheated regenerative chain of secondary circuit in Cernavoda NPP which could be extended up to cover the whole secondary circuit by including the analysis of steam generators, turbine, and steam condenser. (authors)

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

International Nuclear Information System (INIS)

Shekarchian, M.; Zarifi, F.; Moghavvemi, M.; Motasemi, F.; Mahlia, T.M.I.

2013-01-01

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

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

OpenAIRE

Dolianitis Ioannis; Giannakopoulos Dionysios; Hatzilau Christina-Stavrula; Karellas Sotirios; Kakaras Emmanuil; Nikolova Evelina; Skarpetis Georgios; Christodoulou Nikolaos; Giannoulas Nikolaos; Zitounis Theodoros

2016-01-01

A promising option to reduce the specific energy consumption and CO2 emissions at a conventional natural gas fired container glass furnace deals with the advanced utilization of the exhaust gases downstream the air regenerators by means of batch and cullet preheating. A 3-dimensional computational model that simulates this process using mass and heat transfer equations inside a preheater has been developed. A case study for an efficient small-sized containe...

Hybrid preheat/recirculating steam generator

International Nuclear Information System (INIS)

Lilly, G.P.

1985-01-01

The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

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.

Preheating Mechanism in F-term SUSY Hybrid Inflation

International Nuclear Information System (INIS)

Mazumdar, Arindam

2012-01-01

Supersymmetric F-term hybrid inflation is one of the most popular models of inflation. Preheating process occurs in this model via two different mechanism. Firstly the standard parametric resonance and secondly, the tachyonic preheating. Generally tachyonic preheating dominates the parametric resonance for this type of models. For different values of the parameters of the theory dominance of tachyonic preheating can vary.

7 CFR 58.919 - Pre-heat, pasteurization.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Pre-heat, pasteurization. 58.919 Section 58.919... Procedures § 58.919 Pre-heat, pasteurization. When pasteurization is intended or required by either the vat... requirements outlined in § 58.128. Pre-heat temperatures prior to ultra pasteurization will be those that have...

Hydrogen preheating through waste heat recovery of an open-cathode PEM fuel cell leading to power output improvement

International Nuclear Information System (INIS)

Mohamed, W.A.N.W.; Kamikl, M. Haziq M.

2016-01-01

Highlights: • A study on the effect of hydrogen preheating using waste heat for low temperature PEM fuel cells. • Theoretical, experimental and analytical framework was established. • The maximum electrical power output increases by 8–10% under specific operating conditions. • Open loop hydrogen supply gives a better performance than closed loop. • The waste heat utilization is less than 10% due to heat capacity limitations. - Abstract: The electrochemical reaction kinetics in a Polymer Electrolyte Membrane (PEM) fuel cell is highly influenced by the reactants supply pressures and electrode temperatures. For an open cathode PEM fuel cell stack, the power output is constrained due to the use of air simultaneously as reactant and coolant. Optimal stack operation temperatures are not achieved especially at low to medium power outputs. Based on the ideal gas law, higher reactant temperatures would lead to higher pressures and subsequently improve the reaction kinetics. The hydrogen supply temperature and its pressure can be increased by preheating; thus, slightly offsetting the limitation of low operating stack temperatures. The exit air stream offers an internal source of waste heat for the hydrogen preheating purpose. In this study, a PEM open-cathode fuel cell was used to experimentally evaluate the performance of hydrogen preheating based on two waste heat recovery approaches: (1) open-loop and (2) closed loop hydrogen flow. The stack waste heat was channelled into a heat exchanger to preheat the hydrogen line before it is being supplied (open loop) or resupplied (closed loop) into the stack. At a constant 0.3 bar hydrogen supply pressure, the preheating increases the hydrogen temperature in the range of 2–13 °C which was dependant on the stack power output and cathode air flow rates. The achievable maximum stack power was increased by 8% for the closed loop and 10% for the open loop. Due to the small hydrogen flow rates, the waste heat utilization

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.

Low cost bare-plate solar air collector

Science.gov (United States)

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

1980-09-01

A low cost, bare plate solar collector for preheating ambient air was developed. This type of solar heating system would be applicable for preheating ventilation air for public buildings or other commercial and industrial ventilation requirements. Two prototype collectors were designed, fabricated and installed into an instrumented test system. Tests were conducted for a period of five months. Results of the tests showed consistent operating efficiencies of 60 percent or greater with air preheat temperature uses up to 20 degrees for one of the prototypes. The economic analyses indicated that this type of solar system was economically viable. For the materials of construction and the type of fabrication and installation perceived, costs for the bare plate solar collector are attainable. Applications for preheating ventilation air for schools were evaluated and judged to be economically viable.

Effect of inflation on parametric resonance during preheating

International Nuclear Information System (INIS)

Hirai, Shiro

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 k between two initial conditions is shown to be not so large. Rather, the ratio n 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 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

Dynamics of Symmetry Breaking and Tachyonic Preheating

CERN Document Server

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

2001-01-01

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

Preheating in new inflation

International Nuclear Information System (INIS)

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

2005-01-01

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

Thermal energy analysis of a lime production process: Rotary kiln, preheater and cooler

International Nuclear Information System (INIS)

Shahin, Hamed; Hassanpour, Saeid; Saboonchi, Ahmad

2016-01-01

Highlights: • The integrated model for lime production unit which includes cooler, preheater and rotary kiln is developed. • The effect of residence time in each section on efficiency is investigated. • Influence of material feed rate and excess air on specific fuel consumption is analyzed. • The significant effect of particle size on efficiency and specific fuel consumption is shown. - Abstract: In this paper, thermal energy analysis of three zones of a lime production process, which are preheater, rotary kiln and cooler, is performed. In order to perform a proper quantitative estimation, the system was modeled using energy balance equations including coupled heat transfer and chemical reaction mechanisms. A mathematical model was developed, and consequently, the thermal and chemical behavior of limestone was investigated. The model was verified using empirical data. After model confirmation, the variation of Specific Fuel Consumption (SFC) versus production rate was predicted and the optimum condition was determined. Subsequently, fuel consumption was calculated regarding to altered residence time inside each zone of lime production process, for a constant output. Results indicate that increasing the residence time inside each zone of lime production process, will enhance thermal efficiency and saves fuel consumption. Relative enhancement will be the same for different sizes of limestone. It was found that a 10-min increase in material residence time inside the preheater or rotary kiln can reduce fuel consumption by around two percent. Whereas, a 5-min increase in material residence time inside the cooler would be enough to obtain a similar result. Finally, the ratio of air-to-fuel and production rate are changed in such a way that the same product is achieved. The model predicts that lowering excess air from 15% to 10% leads to a 2.5% reduction of Specific Fuel Consumption (SFC).

Pre-heating mitigates composite degradation.

Science.gov (United States)

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

2015-01-01

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

Experimental investigation of laminar LPG-H{sub 2} jet diffusion flame with preheated reactants

Energy Technology Data Exchange (ETDEWEB)

D.P. Mishra; P. Kumar [Indian Institute of Technology, Kanpur (India). Combustion Laboratory, Department of Aerospace Engineering

2008-10-15

This paper presents an experimental investigation of the effect of H{sub 2} addition on flame length, soot free length fraction (SFLF), flame radiant fraction, gas temperature and emission level in LPG-H{sub 2} composite fuel jet diffusion flame for two preheated cases namely, (i) preheated air and (ii) preheated air and fuel. Results show that the H{sub 2} addition leads to a reduction in flame length which may be caused due to an increased gas temperature. Besides this, the flame length is also observed to be reduced with increasing reactants temperature. The soot free length fraction (SFLF) increases as H{sub 2} is added to fuel stream. This might have been caused by decrease in the C/H ratio in the flame and is favorable to attenuate PAH formation rate. Interestingly, the SFLF is observed to be reduced with increasing reactants temperature that may be due to reduction in induction period of soot formation caused by enhanced flame temperature. Moreover, the decreased radiant heat fraction with hydrogen addition is pertinent with the reduction in soot concentration level. The reduction in NOx emission level with H{sub 2} addition to the fuel stream is also observed. On the contrary, NOx emission level is found to be enhanced significantly with reactant temperature that can be attributed to the increase in thermal NOx through Zeldovich mechanism. 31 refs., 4 figs., 2 tabs.

On the generation of a non-gaussian curvature perturbation during preheating

Energy Technology Data Exchange (ETDEWEB)

Kohri, Kazunori; Lyth, David H. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Valenzuela-Toledo, Cesar A., E-mail: k.kohri@lancaster.ac.uk, E-mail: d.lyth@lancaster.ac.uk, E-mail: cavalto@ciencias.uis.edu.co [Escuela de Física, Universidad Industrial de Santander, Ciudad Universitaria, Bucaramanga (Colombia)

2010-02-01

The perturbation of a light field might affect preheating and hence generate a contribution to the spectrum and non-gaussianity of the curvature perturbation ζ. The field might appear directly in the preheating model (curvaton-type preheating) or indirectly through its effect on a mass or coupling (modulated preheating). We give general expressions for ζ based on the δN formula, and apply them to the cases of quadratic and quartic chaotic inflation. For the quadratic case, curvaton-type preheating is ineffective in contributing to ζ, but modulated preheating can be effective. For quartic inflation, curvaton-type preheating may be effective but the usual δN formalism has to be modified. We see under what circumstances the recent numerical simulation of Bond et al. [0903.3407] may be enough to provide a rough estimate for this case.

On the generation of a non-gaussian curvature perturbation during preheating

International Nuclear Information System (INIS)

Kohri, Kazunori; Lyth, David H.; Valenzuela-Toledo, Cesar A.

2010-01-01

The perturbation of a light field might affect preheating and hence generate a contribution to the spectrum and non-gaussianity of the curvature perturbation ζ. The field might appear directly in the preheating model (curvaton-type preheating) or indirectly through its effect on a mass or coupling (modulated preheating). We give general expressions for ζ based on the δN formula, and apply them to the cases of quadratic and quartic chaotic inflation. For the quadratic case, curvaton-type preheating is ineffective in contributing to ζ, but modulated preheating can be effective. For quartic inflation, curvaton-type preheating may be effective but the usual δN formalism has to be modified. We see under what circumstances the recent numerical simulation of Bond et al. [0903.3407] may be enough to provide a rough estimate for this case

Liquid-phase synthesis of vertically aligned carbon nanotubes and related nanomaterials on preheated alloy substrates

Science.gov (United States)

Yamagiwa, Kiyofumi

2018-02-01

Carbon nanotubes (CNTs) and related nanocarbons were selectively synthesized on commercially available alloy substrates by a simple liquid-phase technique. Fe- and Ni-rich stainless-steel (JIS SUS316L and Inconel®600, respectively) and Ni-Cu alloy (Monel®400) substrates were used for the synthesis, and each substrate was preheated in air to promote the self-formation of catalyst nanolayers on the surface. The substrates were resistance heated in ethanol without any addition of catalysts to grow CNTs. The yield of the CNTs effectively increased when the preheating process was employed. Highly aligned CNT arrays grew on the SUS316L substrate, while non-aligned CNTs and distinctive twisted fibers were observed on the other substrates. An Fe oxide layer was selectively formed on the preheated SUS316L substrate promoting the growth of the CNT arrays. Characterizations including cyclic voltammetry for the arrays revealed that the CNTs possess a comparatively defect-rich surface, which is a desirable characteristic for its application such as electrode materials for capacitors.

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

DEFF Research Database (Denmark)

Nazaroff, W.; Weschler, Charles J.

2004-01-01

Building occupants, including cleaning personnel, are exposed to a wide variety of airborne chemicals when cleaning agents and air fresheners are used in buildings. Certain of these chemicals are listed by the state of California as toxic air contaminants (TACs) and a subset of these are regulated...... by the US federal government as hazardous air pollutants (HAPs). California's Proposition 65 list of species recognized as carcinogens or reproductive toxicants also includes constituents of certain cleaning products and air fresheners. In addition, many cleaning agents and air fresheners contain chemicals...... that can react with other air contaminants to yield potentially harmful secondary products. For example, terpenes can react rapidly with ozone in indoor air generating many secondary pollutants, including TACs such as formaldehyde. Furthermore, ozone-terpene reactions produce the hydroxyl radical, which...

Gravitational radiation from preheating with many fields

International Nuclear Information System (INIS)

Jr, John T. Giblin; Price, Larry R.; 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-Lemaître-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

Gravitational radiation from preheating with many fields

Energy Technology Data Exchange (ETDEWEB)

Jr, John T. Giblin [Department of Physics, Kenyon College, 201 North College Road, Gambier, OH 43022 (United States); Price, Larry R.; Siemens, Xavier, E-mail: giblinj@kenyon.edu, E-mail: larry@gravity.phys.uwm.edu, E-mail: siemens@gravity.phys.uwm.edu [Center for Gravitation and Cosmology, Department of Physics, University of Wisconsin — Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

2010-08-01

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-Lemaître-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.

Method for pre-heating lmfbr type reactors

International Nuclear Information System (INIS)

Yokozawa, Atsushi; Kataoka, Hajime.

1978-01-01

Purpose: To enable pre-heating for the inside of the reactor container and the inside of the coolant recycling system with no additional facilities. Method: The coolant recycling system is composed of a heat exchanger, a mechanical pump, a check valve, a flow meter or the like and it is connected in series by way of a pipe line to a reactor container. The mechanical pump is used as a gas recycling device upon pre-heating and it is designed so that a blower such as a fan can be replaced for the impeller of the pump. The inside of the reactor container and the inside of the coolant recycling system is at first filled with an inert gas such as for use with cover gas. Then, nuclear fuels are loaded to attain criticality. Simultaneously, the blower is started and the control rods are operated while cooling the nuclear fuel with the inert gas thus to obtain heat required for pre-heating the pipe line or the like from the nuclear fuels. After the completion of the pre-heating, the liquid metal is charged. (Ikeda, J.)

Powertrain preheating system of tracked hybrid electric vehicle in cold weather

International Nuclear Information System (INIS)

Wang, Rui; Wang, Yichun; Feng, Chaoqing; Zhang, Xilong

2015-01-01

In order to make sure that the heavy duty tracked vehicle can work in various conditions, especially severe cold weather, preheating system of powertrain should be adopted, and a novel preheating system is presented for the tracked hybrid electric vehicle (HEV) in which heat is generated by the low-speed drive motor. The new preheating system can meet the need of cold start without adding any additional device. The characteristic of heat generation by motor is tested when the rotor of motor is rotated in very low speed. The heat loss from power cabin to external environment has been simulated, and the relevant test has been done to verify the simulation results. Combining the characteristic of heat generation and heat loss situation about preheating system, the heat transfer model of preheating system was implemented by MATLAB. The total energy required for preheating in different ambient temperature was calculated by this model. The results showed that: the minimum heating power was 70 kW and energy required was about 180 MJ when the HEV worked in −46 °C. If lithium ferrous phosphate (LFP) battery was used in power system, the minimum battery capacity is about 290 A h. - Highlights: • A novel preheating method was proposed for heavy duty tracked HEV. • Thermal energy in preheating system is produced by the PMSM in driving system. • This method can achieve preheating target by its own components without any adding. • Analyzing low temperature performance of power battery and select its capacity.

Numerical simulation of anisotropic preheating ablative Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Wang Lifeng; Ye Wenhua; Li Yingjun

2010-01-01

The linear growth rate of the anisotropic preheating ablative Rayleigh-Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T)=κ SH [1+f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse. (authors)

Numerical Simulation of Anisotropic Preheating Ablative Rayleigh–Taylor Instability

International Nuclear Information System (INIS)

Li-Feng, Wang; Wen-Hua, Ye; Ying-Jun, Li

2010-01-01

The linear growth rate of the anisotropic preheating ablative Rayleigh–Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T) = κ SH [1 + f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse [Phys. Rev. Lett. 98 (2007) 245001]. (physics of gases, plasmas, and electric discharges)

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.

Gauge-preheating and the end of axion inflation

Energy Technology Data Exchange (ETDEWEB)

Adshead, Peter; Sfakianakis, Evangelos I. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Giblin, John T. Jr.; Scully, Timothy R., E-mail: adshead@illinois.edu, E-mail: giblinj@kenyon.edu, E-mail: tscully2@illinois.edu, E-mail: esfaki@illinois.edu [Department of Physics, Kenyon College, 201 North College Rd, Gambier, Ohio 43022 (United States)

2015-12-01

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{sup 2φ2} 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 transfers all of its energy to the gauge fields within a few oscillations. In most cases, we find that the gauge fields on sub-horizon scales end preheating in an unpolarized state due to the existence of strong rescattering between the inflaton and gauge-field 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.

Gauge-preheating and the end of axion inflation

International Nuclear Information System (INIS)

Adshead, Peter; Sfakianakis, Evangelos I.; Giblin, John T. Jr.; Scully, Timothy R.

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 2φ2 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 transfers all of its energy to the gauge fields within a few oscillations. In most cases, we find that the gauge fields on sub-horizon scales end preheating in an unpolarized state due to the existence of strong rescattering between the inflaton and gauge-field 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

Spectroscopic Measurements of Target Preheating on OMEGA

International Nuclear Information System (INIS)

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

2000-01-01

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

Nuclear reactor insulation and preheat system

International Nuclear Information System (INIS)

Wampole, N.C.

1978-01-01

An insulation and preheat system is disclosed for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the ocmpartment. An external surface of the compartment of enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair

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

Gravity waves from tachyonic preheating after hybrid inflation

Energy Technology Data Exchange (ETDEWEB)

Dufaux, Jean-Francois [Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Felder, Gary [Department of Physics, Clark Science Center, Smith College, Northampton, MA 01063 (United States); Kofman, Lev [CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Navros, Olga, E-mail: jeff.dufaux@uam.es, E-mail: gfelder@email.smith.edu, E-mail: kofman@cita.utoronto.ca, E-mail: navros@email.unc.edu [Department of Mathematics, University of North Carolina Chapel Hill, CB3250 Philips Hall, Chapel Hill, NC 27599 (United States)

2009-03-15

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

Are black holes overproduced during preheating?

International Nuclear Information System (INIS)

Suyama, Teruaki; Tanaka, Takahiro; Bassett, Bruce; Kudoh, Hideaki

2005-01-01

We provide a simple but robust argument that primordial black hole production generically does not exceed astrophysical bounds during the resonant preheating phase after inflation. This conclusion is supported by fully nonlinear lattice simulations of various models in two and three dimensions which include rescattering but neglect metric perturbations. We examine the degree to which preheating amplifies density perturbations at the Hubble scale and show that, at the end of the parametric resonance, power spectra are universal, with no memory of the power spectrum at the end of inflation. In addition, we show how the probability distribution of density perturbations changes from exponential on very small scales to Gaussian when smoothed over the Hubble scale - the crucial length for studies of primordial black hole formation - hence justifying the standard assumption of Gaussianity

Effects of Preheat on Weldments of NICOP Steel.

Science.gov (United States)

1983-09-01

percent Nital solution (nitric acid (HNO3) ,* and ethanol (C2HsOH) which revealed the weld area, heat affected zone and base metal. A section 25.2mm (1 inch...electrolyte, consisting of 10% per- cloric acid (HC104 ) and 90% methanal (CH30H) was maintained at a temperature of -450C (-49 0 F). The Polipower was set...Preheated Weidment. N on Non-Preheated Weidment. Figre3. Loaton o McrhadnssTrvese I17 ~.4. .9 G° s s E 43 C 0 CL 44’ 00 Hda *SBUPJQH Figure 4. Comparison

Effect of pre-heat treatment on a Fischer-Tropsch iron catalyst

International Nuclear Information System (INIS)

Rao, K.R.P.M.; Huggins, F.E.; Ganguly, B.; Mahajan, V.; Huffman, G.P.; Davis, B.; O'Brien, R.J.; Xu Liguang; Rao, V.U.S.

1994-01-01

Moessbauer spectroscopy was used to investigate the effect of heating the Fischer-Tropsch catalyst 100 Fe/5 Cu/4.2 K/24 SiO 2 in two different atmospheres while ramping the temperature of the catalyst from room temperature to 280 C in 5.5 h prior to pretreatment of the catalyst. Preheating in H 2 /CO = 0.7 gave rise to an iron (Fe 2+ ) silicate, while preheating in helium resulted in the formation of ε'-carbide Fe 2.2 C. Iron oxides and χ-carbide Fe 5 C 2 were also formed in both preheat treatments. (orig.)

Influence of preheating on grindability of coal

Science.gov (United States)

Lytle, J.; Choi, N.; Prisbrey, K.

1992-01-01

Enormous quantities of coal must be ground as feed to power generation facilities. The energy cost of grinding is significant at 5 to 15 kWh/ton. If grindability could be increased by preheating the coal with waste heat, energy costs could be reduced. The objective of this work was to determine how grindability was affected by preheating. The method was to use population balance grinding models to interpret results of grinding coal before and after a heat treatment. Simulation of locked cycle tests gave a 40% increase in grindability. Approximately 40% grinding energy saving can be expected. By using waste heat for coal treatment, the targeted energy savings would be maintained. ?? 1992.

Effects of dissipation and fluctuation in preheating

International Nuclear Information System (INIS)

Vartuli, Rodrigo; Ramos, Rudnei de O.

2006-01-01

In this paper, we study the effects of dissipation and fluctuation in preheating after inflation. The effective equation of motion for a scalar field χ interacting with lighter fields is derived using the field theoretical method of closed time path due to Schwinger, winch is suitable to study nonequilibrium and time dependent process. In this derivation the emergent equation is intrinsically dissipative and stochastic in nature. The resulting dynamics is then studied both analytically and numerically. The results obtained are then discussed for then relevance for the reheating epoch right after an inflationary phase(preheating) for the case of the evolution of the scalar field χ and its decay into fermion. (author)

Preheating with extra dimensions

International Nuclear Information System (INIS)

Tsujikawa, S.

2000-01-01

We investigate preheating in a higher-dimensional generalized Kaluza-Klein theory with a quadratic inflaton potential V(/φ) = /frac12 m 2 /φ 2 including metric perturbations explicitly. The system we consider is the multi-field model where there exists a dilaton field /σ which corresponds to the scale of compactifications and another scalar field /χ coupled to inflaton with the interaction frac12 g 2 /φ 2 /χ 2 +/g-tilde 2 /φ 3 /χ. In the case of g-tilde=0, we find that the perturbation of dilaton does not undergo parametric amplification while the χ field fluctuation can be enhanced in the usual manner by parametric resonance. In the presence of the /g-tilde 2 /φ 3 /χ coupling, the dilaton fluctuation in sub-Hubble scales is modestly amplified by the growth of metric perturbations for the large coupling g-tilde. In super-Hubble scales, the enhancement of the dilaton fluctuation as well as metric perturbations is weak, taking into account the backreaction effect of created /χ particles. We argue that not only is it possible to predict the ordinary inflationary spectrum in large scales but extra dimensions can be held static during preheating in our scenario. (author)

Nuclear fuel preheating system

International Nuclear Information System (INIS)

Andrea, C.

1975-01-01

A nuclear reactor new fuel handling system which conveys new fuel from a fuel preparation room into the reactor containment boundary is described. The handling system is provided with a fuel preheating station which is adaptd to heat the new fuel to reactor refueling temperatures in such a way that the fuel is heated from the top down so that fuel element cladding failure due to thermal expansions is avoided. (U.S.)

Influence of Powder Bed Preheating on Microstructure and Mechanical Properties of H13 Tool Steel SLM Parts

Science.gov (United States)

Mertens, R.; Vrancken, B.; Holmstock, N.; Kinds, Y.; Kruth, J.-P.; Van Humbeeck, J.

Powder bed preheating is a promising development in selective laser melting (SLM), mainly applied to avoid large thermal stresses in the material. This study analyses the effect of in-process preheating on microstructure, mechanical properties and residual stresses during SLM of H13 tool steel. Sample parts are produced without any preheating and are compared to the corresponding parts made with preheating at 100°, 200°, 300°, and 400°C. Interestingly, internal stresses at the top surface of the parts evolve from compressive (-324MPa) without preheating to tensile stresses (371MPa) with preheating at 400°C. Nevertheless, application of powder bed preheating results in a more homogeneous microstructure with better mechanical properties compared to H13 SLM parts produced without preheating. The fine bainitic microstructure leads to hardness values of 650-700Hv and ultimate tensile strength of 1965MPa, which are comparable to or even better than those of conventionally made and heat treated H13 tool steel.

Secondary air injection system and method

Science.gov (United States)

Wu, Ko-Jen; Walter, Darrell J.

2014-08-19

According to one embodiment of the invention, a secondary air injection system includes a first conduit in fluid communication with at least one first exhaust passage of the internal combustion engine and a second conduit in fluid communication with at least one second exhaust passage of the internal combustion engine, wherein the at least one first and second exhaust passages are in fluid communication with a turbocharger. The system also includes an air supply in fluid communication with the first and second conduits and a flow control device that controls fluid communication between the air supply and the first conduit and the second conduit and thereby controls fluid communication to the first and second exhaust passages of the internal combustion engine.

Feed water pre-heater with two steam spaces

International Nuclear Information System (INIS)

Tratz, H.; Kelp, F.; Netsch, E.

1976-01-01

A feed water pre-heater for the two stage heating of feed water by condensing steam, having a low installed height is described, which can be installed in the steam ducts of turbines of large output, as in LWRs in nuclear power stations. The inner steam space is closed on one side by the water vessel, while the tubes of the inner steam space go straight from the water vessel, and the tubes of the outer steam space are bent into a U shape and open out into the water vessel. The two-stage preheater is thus surrounded by feedwater in two ways. (UWI) [de

Theory and numerics of gravitational waves from preheating after inflation

International Nuclear Information System (INIS)

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

2007-01-01

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

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.)

DEFROST: a new code for simulating preheating after inflation

International Nuclear Information System (INIS)

Frolov, Andrei V

2008-01-01

At the end of inflation, dynamical instability can rapidly deposit the energy of homogeneous cold inflaton into excitations of other fields. This process, known as preheating, is rather violent, inhomogeneous and non-linear, and has to be studied numerically. This paper presents a new code for simulating scalar field dynamics in an expanding universe written for that purpose. Compared to available alternatives, it significantly improves both the speed and the accuracy of calculations, and is fully instrumented for 3D visualization. We reproduce previously published results on preheating in simple chaotic inflation models, and further investigate non-linear dynamics of the inflaton decay. Surprisingly, we find that the fields do not 'want' to thermalize in quite the way that one would think. Instead of directly reaching equilibrium, the evolution appears to be stuck in a rather simple but quite inhomogeneous state. In particular, a one-point distribution function of total energy density appears to be universal among various two-field preheating models, and is exceedingly well described by a log-normal distribution. It is tempting to attribute this state to scalar field turbulence

Preheating of tap water with solar collectors

Energy Technology Data Exchange (ETDEWEB)

Granum, H; Raaen, H

1992-05-05

In 1991 SINTEF Architecture and Building Technology won the second prize in 'The Nordic Competition for Low Energy Buildings' with a project proposal named 'LOWe'. The paper gives a description of the energy-saving features of this project, particularly the use of a solar collector for preheating of tap water. Compared with the economic profitability of other saving efforts in the project, such as good thermal insulation and efficient heat recovering system, the system for solar preheating of tap water does not seem very attractive for the time being. Loose estimates indicate a cost of close of NOK 1.00 per kWh for the produced energy in the solar collector, while the present price for electricity in Norway is about NOK 0.50 per kWh. Compared with a heat pump solution however the energy cost is not unreasonable.

Effects of substrate preheating during direct energy deposition on microstructure, hardness, tensile strength, and notch toughness

Science.gov (United States)

Baek, Gyeong Yun; Lee, Ki Yong; Park, Sang Hu; Shim, Do Sik

2017-11-01

This study examined the effects of substrate preheating for the hardfacing of cold-press dies using the high-speed tool steel AISI M4. The preheating of the substrate is a widely used technique for reducing the degree of thermal deformation and preventing crack formation. We investigated the changes in the metallurgical and mechanical properties of the high-speed tool steel M4 deposited on an AISI D2 substrate with changes in the substrate preheating temperature. Five preheating temperatures (100-500 °C; interval of 100 °C) were selected, and the changes in the temperature of the substrate during deposition were observed. As the preheating temperature of the substrate was increased, the temperature gradient between the melting layer and the substrate decreased; this prevented the formation of internal cracks, owing to thermal stress relief. Field-emission scanning electron microscopy showed that a dendritic structure was formed at the interface between the deposited layer and the substrate while a cellular microstructure was formed in the deposited layer. As the preheating temperature was increased, the sizes of the cells and precipitated carbides also increased. Furthermore, the hardness increased slightly while the strength and toughness decreased. Moreover, the tensile and impact properties deteriorated rapidly at excessively high preheating temperatures (greater than 500 °C). The results of this study can be used as preheating criteria for achieving the desired mechanical properties during the hardfacing of dies and molds.

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

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 age, from...... is consistent with a kinetic analysis of sensitivity-corrected IRSL data. The corollary to our observations is that shallow (unstable) traps do not give rise to a significant IRSL signal....

CFD modeling of fouling in crude oil pre-heaters

International Nuclear Information System (INIS)

Bayat, Mahmoud; Aminian, Javad; Bazmi, Mansour; Shahhosseini, Shahrokh; Sharifi, Khashayar

2012-01-01

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.

Discussion on Boiler Efficiency Correction Method with Low Temperature Economizer-Air Heater System

Science.gov (United States)

Ke, Liu; Xing-sen, Yang; Fan-jun, Hou; Zhi-hong, Hu

2017-05-01

This paper pointed out that it is wrong to take the outlet flue gas temperature of low temperature economizer as exhaust gas temperature in boiler efficiency calculation based on GB10184-1988. What’s more, this paper proposed a new correction method, which decomposed low temperature economizer-air heater system into two hypothetical parts of air preheater and pre condensed water heater and take the outlet equivalent gas temperature of air preheater as exhaust gas temperature in boiler efficiency calculation. This method makes the boiler efficiency calculation more concise, with no air heater correction. It has a positive reference value to deal with this kind of problem correctly.

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

Directory of Open Access Journals (Sweden)

Doo-ngam, N.

2007-11-01

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

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

International Nuclear Information System (INIS)

Battefeld, Thorsten; Eggemeier, Alexander; Giblin, John T. Jr.

2012-01-01

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

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.

Preheat-induced signal enhancement in the infrared stimulated luminescence of young and bleached sediment samples

International Nuclear Information System (INIS)

Richardson, C.A.

2000-01-01

Natural and laboratory bleached surface and young samples of potassium feldspar sand separates and polymineral silt had their infrared stimulated luminescence (IRSL) signal measured before and after preheating at 220 deg. C for 10 min or 160 deg. C for 16 h. For both preheats, the laboratory bleached sand samples underwent a signal enhancement which was stable with laboratory storage. The youngest samples also showed natural signal enhancement. The silt sample showed no recuperation of bleached signal on preheating, but some in the natural signal. A range of filtered bleaches was applied to one surface sand sample. Signal levels before and after preheating were reduced by filtering out the UV from the bleaching spectrum. The unfiltered bleach, however, most closely reproduced the behaviour of the natural sample

Analysis of pre-heated fuel combustion and heat-emission dynamics in a diesel engine

Science.gov (United States)

Plotnikov, S. A.; Kartashevich, A. N.; Buzikov, S. V.

2018-01-01

The article explores the feasibility of diesel fuel pre-heating. The research goal was to obtain and analyze the performance diagrams of a diesel engine fed with pre-heated fuel. The engine was tested in two modes: at rated RPMs and at maximum torque. To process the diagrams the authors used technique developed by the Central Diesel Research Institute (CDRI). The diesel engine’s heat emission curves were obtained. The authors concluded that fuel pre-heating shortened the initial phase of the combustion process and moderated the loads, thus making it possible to boost a diesel engine’s mean effective pressure.

Preliminary studies of using preheated carrier gas for on-line membrane extraction of semivolatile organic compounds.

Science.gov (United States)

Liu, Xinyu; Pawliszyn, Janusz

2007-04-01

In this paper, we present results for the on-line determination of semivolatile organic compounds (SVOCs) in air using membrane extraction with a sorbent interface-ion mobility spectrometry (MESI-IMS) system with a preheated carrier (stripping) gas. The mechanism of the mass transfer of SVOCs across a membrane was initially studied. In comparison with the extraction of volatile analytes, the mass transfer resistance that originated from the slow desorption from the internal membrane surface during the SVOC extraction processes should be taken into account. A preheated carrier gas system was therefore built to facilitate desorption of analytes from the internal membrane surface. With the benefit of a temperature gradient existing between the internal and external membrane surfaces, an increase in the desorption rate of a specific analyte at the internal surface and the diffusion coefficient within the membrane could be achieved while avoiding a decrease of the distribution constant on the external membrane interface. This technique improved both the extraction rate and response times of the MESI-IMS system for the analysis of SVOCs. Finally, the MESI-IMS system was shown to be capable of on-site measurement by monitoring selected polynuclear aromatic hydrocarbons emitted from cigarette smoke.

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-11-01

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

Formation of toroidal pre-heat plasma without residual magnetic field for high-beta pinch experiments

International Nuclear Information System (INIS)

Ikeda, Nagayasu; Tamaru, Ken; Nagata, Akiyoshi.

1979-01-01

Formation of toroidal pre-heat plasma was studied. The pre-heat plasma without residual magnetic field was made by chopping the current for pre-heat, A small toroidal-pinch system was used for the experiment. The magnetic field was measured with a magnetic probe. One turn loop was used for the measurement of the toroidal one-turn electric field. A pair of Rogoski coil was used for the measurement of plasma current. The dependence of residual magnetic field on chopping time was measured. By fast chopping of the primary current in the pre-heating circuit, the poloidal magnetic field was reduced to several percent within 5 microsecond. After chopping, no instability was observed in the principal discharge plasma produced within several microsecond. As the conclusion, it can be said that the control of residual field can be made by current chopping. (Kato, T.)

Air/liquid collectors

DEFF Research Database (Denmark)

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

1997-01-01

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......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...

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

International Nuclear Information System (INIS)

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

2016-01-01

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. (paper)

Calculation and design of natural gas preheater equipments. Berechnung und Auslegung von Erdgas-Vorwaermeanlagen

Energy Technology Data Exchange (ETDEWEB)

Fasold, H G [Ruhrgas AG, Essen (Germany); Wahle, H N [Ruhrgas AG, Essen (Germany)

1994-04-01

A greatly simplified model of a regulating station - consisting of the station components ''preheater'' and ''control unit'' - is used for the calculation and design of natural gas preheating plants. It is hereby possible to calculate the Joule-Thomson effect which occurs on the expansion of natural gas in the controller, the resulting drop in temperature and the thermal output required to compensate this which is to be supplied to the gas flow by the preheating plant. The calculation method and procedure are explained using a programming flowchart. The computational model presented was converted into a personal computer program, whose functioning is elucidated using a numerical example. (orig.)

Sintering uranium oxide using a preheating step

International Nuclear Information System (INIS)

Jensen, N.J.; Nivas, Y.; Packard, D.R.

1977-01-01

Compacted pellets of uranium oxide or uranium oxide with one or more additives are heated in a kiln in a process having a preheating step, a sintering step, a reduction step, and a cooling step in a controlled atmosphere. The process is practiced to give a range of temperature and atmosphere conditions for obtaining optimum fluoride removal from the compacted pellets along with optimum sintering in a single process. The preheating step of this process is conducted in a temperature range of about 600 0 to about 900 0 C and the pellets are held for at least twenty min, and preferably about 60 min, in an atmosphere having a composition in the range of about 10 to about 75 vol % hydrogen with the balance being carbon dioxide. The sintering step is conducted at a temperature in the range of about 900 0 C to 1500 0 C in the presence of an atmosphere having a composition in the range of about 0.5 to about 90 vol % hydrogen with the balance being carbon dioxide. The reduction step reduces the oxygen to metal ratio of the pellets to a range of about 1.98 to 2.10:1 and this is accomplished by gradually cooling the pellets for about 30 to about 120 min from the temperature of the sintering step to about 1100 0 C in an atmosphere of about 10 to 90 vol % hydrogen with the balance being carbon dioxide. Thereafter the pellets are cooled to about 100 0 C under a protective atmosphere, and in one preferred practice the same atmosphere used in the reduction step is used in the cooling step. The preheating, sintering and reduction steps may also be conducted with their respective atmospheres having an initial additional component of water vapor and the water vapor can comprise up to about 20 vol %

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.

Assessment of Feasibility of the Beneficial Use of Waste Heat from the Advanced Test Reactor

Energy Technology Data Exchange (ETDEWEB)

Donna P. Guillen

2012-07-01

This report investigates the feasibility of using waste heat from the Advanced Test Reactor (ATR). A proposed glycol waste heat recovery system was assessed for technical and economic feasibility. The system under consideration would use waste heat from the ATR secondary coolant system to preheat air for space heating of TRA-670. A tertiary coolant stream would be extracted from the secondary coolant system loop and pumped to a new plate and frame heat exchanger, where heat would be transferred to a glycol loop for preheating outdoor air in the heating and ventilation system. Historical data from Advanced Test Reactor operations over the past 10 years indicates that heat from the reactor coolant was available (when needed for heating) for 43.5% of the year on average. Potential energy cost savings by using the waste heat to preheat intake air is $242K/yr. Technical, safety, and logistics considerations of the glycol waste heat recovery system are outlined. Other opportunities for using waste heat and reducing water usage at ATR are considered.

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)

Mohd Fahmi Mohd Yusof; Robert, T.S.B.; Puteri Norkhatijah Abdul Hamid; Nor Shazleen Abdul Shukor; Mohd Sazarman Mohd Salleh

2013-01-01

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)

Plasma formation and target preheating by prepulse of PW laser light

Science.gov (United States)

Sentoku, Yasuhiko; Iwata, Natsumi; Koga, James; Dover, Nicholas; Nishiuchi, Mamiko

2017-10-01

An intense short pulse laser with intensity over 1021 W/cm2 has become available, i.e. J-KAREN-P at QST. Although the contrast of the short pulse is improved to be of the order of 10-11, there is an unavoidable prepulse, which has multiple spikes (ps) on top of an exponential profile with intensity greater than 1014 W/cm2 about 50 ps in front of the main pulse. The prepulse preheats the target and also produces tenuous plasmas in front of a target before the main pulse arrives. It is critical to understand such preheating of the target, where the nonlocal heat transport is essential at intensity >1014 W/cm2, since the target condition might totally change before the interaction with the main pulse. Using a hydro code, FLASH, and a collisional particle-in-cell code, PICLS, we study the preplasma formation and target preheating over tens of picoseconds timescale, and discuss the prepulse effects on the main pulse interaction. Work supported by the JSPS KAKENHI under Grant No. JP15K21767.

From (p)reheating to nucleosynthesis

International Nuclear Information System (INIS)

Jedamzik, Karsten

2002-01-01

This paper gives a brief qualitative description of the possible evolution of the early universe between the end of an inflationary epoch and the end of big-bang nucleosynthesis. After a general introduction, establishing the minimum requirements cosmologists impose on this cosmic evolutionary phase, namely, successful baryogenesis, the production of cosmic dark matter and successful light-element nucleosynthesis, a more detailed discussion on some recent developments follows. This latter includes the physics of preheating, the putative production of (alternative) dark matter and the current status of big bang nucleosynthesis

Secondary Aluminum Production: National Emission Standards for Hazardous Air Pollutants

Science.gov (United States)

National emission standards for hazardous air pollutants (NESHAP) for new and existing sources at secondary aluminum production facilities. Includes rule history, summary, federal register citations and implementation information.

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.

Production of gravitational waves during preheating with nonminimal coupling

Science.gov (United States)

Fu, Chengjie; Wu, Puxun; Yu, Hongwei

2018-04-01

We study the preheating and the in-process production of gravitational waves (GWs) after inflation in which the inflaton is nonminimally coupled to the curvature in a self-interacting quartic potential with the method of lattice simulation. We find that the nonminimal coupling enhances the amplitude of the density spectrum of inflaton quanta, and as a result, the peak value of the GW spectrum generated during preheating is enhanced as well and might reach the limit of detection in future GW experiments. The peaks of the GW spectrum not only exhibit distinctive characteristics as compared to those of minimally coupled inflaton potentials but also imprint information on the nonminimal coupling and the parametric resonance, and thus the detection of these peaks in the future will provide us a new avenue to reveal the physics of the early universe.

Hydrodynamic and thermal mechanisms of filtration combustion inclinational instability based on non-uniform distribution of initial preheating temperature

Science.gov (United States)

Xia, Yongfang; Shi, Junrui; Xu, Youning; Ma, Rui

2018-03-01

Filtration combustion (FC) is one style of porous media combustion with inert matrix, in which the combustion wave front propagates, only downstream or reciprocally. In this paper, we investigate the FC flame front inclinational instability of lean methane/air mixtures flowing through a packed bed as a combustion wave front perturbation of the initial preheating temperature non-uniformity is assumed. The predicted results show that the growth rate of the flame front inclinational angle is proportional to the magnitude of the initial preheating temperature difference. Additionally, depending on gas inlet gas velocity and equivalence ratio, it is demonstrated that increase of gas inlet gas velocity accelerates the FC wave front deformation, and the inclinational instability evolves faster at lower equivalence ratio. The development of the flame front inclinational angle may be regarded as a two-staged evolution, which includes rapid increase, and approaching maximum value of inclinational angle due to the quasi-steady condition of the combustion system. The hydrodynamic and thermal mechanisms of the FC inclinational instability are analyzed. Consequently, the local propagation velocity of the FC wave front is non-uniform to result in the development of inclinational angle at the first stage of rapid increase.

Pre-HEAT: submillimeter site testing and astronomical spectra from Dome A, Antarctica

Science.gov (United States)

Kulesa, C. A.; Walker, C. K.; Schein, M.; Golish, D.; Tothill, N.; Siegel, P.; Weinreb, S.; Jones, G.; Bardin, J.; Jacobs, K.; Martin, C. L.; Storey, J.; Ashley, M.; Lawrence, J.; Luong-Van, D.; Everett, J.; Wang, L.; Feng, L.; Zhu, Z.; Yan, J.; Yang, J.; Zhang, X.-G.; Cui, X.; Yuan, X.; Hu, J.; Xu, Z.; Jiang, Z.; Yang, H.; Li, Y.; Sun, B.; Qin, W.; Shang, Z.

2008-07-01

Pre-HEAT is a 20 cm aperture submillimeter-wave telescope with a 660 GHz (450 micron) Schottky diode heterodyne receiver and digital FFT spectrometer for the Plateau Observatory (PLATO) developed by the University of New South Wales. In January 2008 it was deployed to Dome A, the summit of the Antarctic plateau, as part of a scientific traverse led by the Polar Research Institute of China and the Chinese Academy of Sciences. Dome A may be one of the best sites in the world for ground based Terahertz astronomy, based on the exceptionally cold, dry and stable conditions which prevail there. Pre-HEAT is measuring the 450 micron sky opacity at Dome A and mapping the Galactic Plane in the 13CO J=6-5 line, constituting the first submillimeter measurements from Dome A. It is field-testing many of the key technologies for its namesake -- a successor mission called HEAT: the High Elevation Antarctic Terahertz telescope. Exciting prospects for submillimeter astronomy from Dome A and the status of Pre-HEAT will be presented.

The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages.

Science.gov (United States)

Sadler, D H; Young, O A

1993-01-01

Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage. Texture analysis was carried out on formulations which had 20% of meat protein replaced by 20% tendons which were raw or had been preheated to 50, 60, 70, or 80°C. Fracturability decreased by about 40% with raw tendon, but was restored to within 20% of the no-replacement control if the tendon had been preheated. Hardness was approximately doubled by replacement with raw tendon or tendon heated at 50°C. At temperatures higher than that, hardness returned to approximately no-replacement levels. For sensory evaluation (0-25% replacement; preheating at 70°C), sausages were assessed by a 12-member panel for texture, flavour and overall acceptability. All attributes decreased with increasing collagen content, the decrease being less marked with preheated tendon. Thus more connective tissue could be added for the same panel score if the tissue was preheated. Comparison of the texture profile and the panel scores for texture at the same lean replacement level suggested that reduced fracturability was the texture parameter that panellists objected to when heated tendon replaced some of the lean. Other researchers have shown that connective tissue preheated to 100°C before addition in emulsion sausages results in improved yields and better sensory attributes, but the present results show that temperatures as low as 60°C can be effective for beef tendon. Copyright © 1993. Published by Elsevier Ltd.

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.

Diagnostics of electron-heated solar flare models. III - Effects of tapered loop geometry and preheating

Science.gov (United States)

Emslie, A. G.; Li, Peng; Mariska, John T.

1992-01-01

A series of hydrodynamic numerical simulations of nonthermal electron-heated solar flare atmospheres and their corresponding soft X-ray Ca XIX emission-line profiles, under the conditions of tapered flare loop geometry and/or a preheated atmosphere, is presented. The degree of tapering is parameterized by the magnetic mirror ratio, while the preheated atmosphere is parameterized by the initial upper chromospheric pressure. In a tapered flare loop, it is found that the upward motion of evaporated material is faster compared with the case where the flare loop is uniform. This is due to the diverging nozzle seen by the upflowing material. In the case where the flare atmosphere is preheated and the flare geometry is uniform, the response of the atmosphere to the electron collisional heating is slow. The upward velocity of the hydrodynamic gas is reduced due not only to the large coronal column depth, but also to the increased inertia of the overlying material. It is concluded that the only possible electron-heated scenario in which the predicted Ca XIX line profiles agree with the BCS observations is when the impulsive flare starts in a preheated dense corona.

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

Science.gov (United States)

2010-07-01

... the data handling procedures for the reported data). 2.3Comparisons with the Primary and Secondary... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY...

77 FR 16987 - National Emission Standards for Hazardous Air Pollutants: Secondary Aluminum Production

Science.gov (United States)

2012-03-23

... National Emission Standards for Hazardous Air Pollutants: Secondary Aluminum Production AGENCY... for secondary aluminum production (77 FR 8576). The EPA is extending the deadline for written comments... from the Aluminum Association. The Aluminum Association has requested the extension in order to allow...

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)

Rossi, C.E.

1993-01-01

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

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

International Nuclear Information System (INIS)

Sid -Ahmed, M.O.; Hussien, T.

1994-01-01

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 )

Utilization of biogas released from palm oil mill effluent for power generation using self-preheated reactor

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Wahid, Mazlan Abdul

2015-01-01

Highlights: • A lab-scale reactor called self-preheating flameless combustion (SPFC) system is experimented. • Feasibility of power generation by POME biogas is modeled using SPFC system. • 4 MW power is available by POME biogas utilization in a typical palm oil mill with 300,000 tons production. • The rate of power generation increases when 2% hydrogen is added to POME biogas ingredients. - Abstract: In palm oil mills, for one ton crude palm oil (CPO) production, 70 m"3 biogas is released from palm oil mill effluent (POME) which can endanger the environment. Palm oil mills without appropriate strategies for biogas collection can participate in greenhouse gases (GHGs) generation actively. In this paper, a typical palm oil mill with annual capacity of 300,000 ton oil palm production and 3 MW electricity demand is considered as a pilot plant and feasibility of power generation by POME biogas is modeled by Aspen Plus considering flameless mode in combustion system. A new design of lab-scale flameless reactor called self-preheated flameless combustion (SPFC) system is presented and employed in power generation modeling. In SPFC system, the flameless chamber is employed as a heater to preheat an oxidizer over the self-ignition temperature of the fuel. A helical stainless steel pipe (called self-preheating pipe) is installed inside the chamber to conduct the oxidizer from exhaust zone to the combustion zone inside the chamber and preheat oxidizer. In the flameless mode, the diluted oxidizer is injected to the helical pipe from the exhaust zone and the preheated oxidizer at the burner is conducted to the flameless furnace through a distributor. In SPFC system external heater for preheating oxidizer is removed and the rate of power generation increases. The results show that 10.8 MW power could be generated in ultra-lean POME biogas SPFC. However, the rate of pollutant especially CO_2 and NO_x is high in this circumstances. In stoichiometric condition, 4 MW power

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

International Nuclear Information System (INIS)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu; Zhang, Baohan; Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

When can preheating affect the CMB?

Science.gov (United States)

Tsujikawa, Shinji; Bassett, Bruce A.

2002-05-01

We discuss the principles governing the selection of inflationary models for which preheating can affect the CMB. This is a (fairly small) subset of those models which have nonnegligible entropy/isocurvature perturbations on large scales during inflation. We study new models which belong to this class-two-field inflation with negative nonminimal coupling and hybrid/double/supernatural inflation models where the tachyonic growth of entropy perturbations can lead to the variation of the curvature perturbation, /R, on super-Hubble scales. Finally, we present evidence against recent claims for the variation of /R in the absence of substantial super-Hubble entropy perturbations.

Fresh fuel pre-heating device in reactor facility

International Nuclear Information System (INIS)

Samejima, Asakuni.

1988-01-01

Purpose: To simplify the structure of a fresh nuclear fuel pre-heating device and improve the reliability to gas supply. Constitution: Fresh fuels taken out from a fresh fuel stredge rack and contained in a fuel strage pipe of a fuel transportation cask are pre-heated at the pre-stage of transfer by sending heating gases from the outside. Gas outlet pipes of the device are led out from the lower portion of the strage pipe, disposed side by side at the top of the strage pipe and opened upwardly. Further, gas supply pipes are connected to the inside of a movable guiding cylinder on the side of the floor surface and the opening end of return pipes are opposed to the exit opening end of the strage pipe. In such a constitution, a gas recycling loop can be formed between the strage pipe and the gas heating device by way of the movable guiding cylinder only by the operation of combining the fuel strage pipe of the transportation cask and the movable guiding pipe disposed on the side of the floor surface. Thus, the coupling structure is facilitated, the connection operation can surely be conducted to improve the reliability as compared with the conventional case. (Horiuchi, T.)

Interaction of regulation and innovation: Solar air heating collectors

OpenAIRE

Kramer, K.

2012-01-01

Solar Air Heating Collectors have still a very small share of 0.8% of the nominal installed capacity in the solar heating and cooling market (151.7 GWth) [1]. Although constituting a niche market, the potential of those kind of collectors to provide heat for industrial processes, processing food, room heating, air preheating, drying processes or air conditioning could be significant. However, the technical potentials of the various technological solutions are not easy to compare. Such a compa...

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

International Nuclear Information System (INIS)

Asta, Eduardo; Zalazar, Monica; Quesada, Hector

2003-01-01

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

Experimental Investigation of the Effects of Concrete Alkalinity on Tensile Properties of Preheated Structural GFRP Rebar

Directory of Open Access Journals (Sweden)

Hwasung Roh

2017-01-01

Full Text Available The combined effects of preexposure to high temperature and alkalinity on the tensile performance of structural GFRP reinforcing bars are experimentally investigated. A total of 105 GFRP bar specimens are preexposed to high temperature between 120°C and 200°C and then immersed into pH of 12.6 alkaline solution for 100, 300, and 660 days. From the test results, the elastic modulus obtained at 300 immersion days is almost the same as those of 660 immersion days. For all alkali immersion days considered in the test, the preheated specimens provide slightly lower elastic modulus than the unpreheated specimens, showing only 8% maximum difference. The tensile strength decreases for all testing cases as the increase of the alkaline immersing time, regardless of the prehearing levels. The tensile strength of the preheated specimens is about 90% of the unpreheated specimen for 300 alkali immersion days. However, after 300 alkali immersion days the tensile strengths are almost identical to each other. Such results indicate that the tensile strength and elastic modulus of the structural GFRP reinforcing bars are closely related to alkali immersion days, not much related to the preheating levels. The specimens show a typical tensile failure around the preheated location.

Tekken tests in a steel 'ASTM A 514 GR B' to determine the preheating temperature

International Nuclear Information System (INIS)

Quesada, Hector Juan; Zalazar, Monica; Asta, Eduardo Pablo

2004-01-01

Cold fissure tests are used to determine the proper preheating temperature in order to prevent fissures during the steel welding process. Tekken tests were carried out on a quenched and tempered high resistance 25.4 mm thick steel (ASTM A514 Gr.B) used in structural applications. The welding was carried out using a FCAW semiautomatic process with gas protection and low hydrogen tubular electrode E110T5-K4. Similar parameters and splicing design were later applied in production. The microstructures of the base material and the welding were determined by optic and electron microscopy. The thermal cycles of the welding were recorded in order to relate the preheating temperature with the cooling time from 800 o C - 500 o C (t 8/5 ) and from 800 o C - 100 o C (tg/1) and the presence or not of fissures. Preheating at 150 o C and t 8/5 greater than 17 s was found to guarantee fissure free welding (CW)

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

Science.gov (United States)

2010-07-01

... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data.... Primary and Secondary Ambient Air Quality Standards for Ozone. 2.1 Data Reporting and Handling Conventions... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of...

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

Science.gov (United States)

Alizadeh Oskoee, Parnian; Pournaghi Azar, Fatemeh; Jafari Navimipour, Elmira; Ebrahimi Chaharom, Mohammad Esmaeel; Naser Alavi, Fereshteh; Salari, Ashkan

2017-01-01

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

Preheating curvaton perturbations

International Nuclear Information System (INIS)

Bastero-Gil, M.; Di Clemente, V.; King, S.F.

2005-01-01

We discuss the potentially important role played by preheating in certain variants of the curvaton mechanism in which isocurvature perturbations of a D-flat (and F-flat) direction become converted to curvature perturbations during reheating. We discover that parametric resonance of the isocurvature components amplifies the superhorizon fluctuations by a significant amount. As an example of these effects we develop a particle physics motivated model which involves hybrid inflation with the waterfall field N being responsible for generating the μ term, the right-handed neutrino mass scale, and the Peccei-Quinn symmetry breaking scale. The role of the curvaton field can be played either by usual Higgs field, or the lightest right-handed sneutrino. Our new results show that it is possible to achieve the correct curvature perturbations for initial values of the curvaton fields of order the weak scale. In this model we show that the prediction for the spectral index of the final curvature perturbation only depends on the mass of the curvaton during inflation, where consistency with current observational data requires the ratio of this mass to the Hubble constant to be 0.3

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.

Effect of pre-heating on the thermal decomposition kinetics of cotton

Science.gov (United States)

The effect of pre-heating at low temperatures (160-280°C) on the thermal decomposition kinetics of scoured cotton fabrics was investigated by thermogravimetric analysis under nonisothermal conditions. Isoconversional methods were used to calculate the activation energies for the pyrolysis after one-...

Symbiotic potential: the integration of preheating and dry cooling in cokemaking

Energy Technology Data Exchange (ETDEWEB)

Barker, J E

1978-06-01

In the USSR and Japan, heat recovered from the dry cooling of coke is used to raise steam for power generation or process use. This heat could be used to dry and preheat coal to improve both coke quality and oven productivity.

Delayed coking unit preheat train optimization; Otimizacao do preaquecimento das Unidades de Coque

Energy Technology Data Exchange (ETDEWEB)

Marins, Edson R; Geraldelli, Washington O; Barros, Francisco C [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

The oil industry has been investing in research and development of new techniques and process improvements with the objective to increase the residual fraction profitability and to fulfill the market demands. The adequacy of the refining scheme has led to the development of bottom of the barrel processes that has the objective to convert heavy fractions into products of higher aggregate value. In this context, the process of Delayed Coking presents a great importance in the production of distillates in the diesel range as well as the processing of heavy residues, mostly in the markets where the fuel oil consumption is being reduced. With the approach to help PETROBRAS decide which route to follow during new designs of Delayed Coking units, this work presents a comparative study of the preheat train performance among the energy recovery to preheat the feed, in contrast with preheating the feed and generating steam, simultaneously. In this study the Pinch Technology methodology was used as a procedure for heat integration with the objective of getting the maximum energy recovery from the process, finding the best trade-off between operational cost and investment cost. The alternative of steam generation aims to provide an appropriate flexibility in Delayed Coking units design and operation. (author)

Minimizing scatter-losses during pre-heat for magneto-inertial fusion targets

Science.gov (United States)

Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, Thomas J.; Bliss, David E.; Glinsky, Michael E.; Gomez, Matthew R.; Harding, Eric; Hansen, Stephanie B.; Jennings, Christopher; Kimmel, Mark W.; Knapp, Patrick; Lewis, Sean M.; Peterson, Kyle; Schollmeier, Marius; Schwarz, Jens; Shores, Jonathon E.; Slutz, Stephen A.; Sinars, Daniel B.; Smith, Ian C.; Speas, C. Shane; Vesey, Roger A.; Weis, Matthew R.; Porter, John L.

2018-02-01

The size, temporal and spatial shape, and energy content of a laser pulse for the pre-heat phase of magneto-inertial fusion affect the ability to penetrate the window of the laser-entrance-hole and to heat the fuel behind it. High laser intensities and dense targets are subject to laser-plasma-instabilities (LPI), which can lead to an effective loss of pre-heat energy or to pronounced heating of areas that should stay unexposed. While this problem has been the subject of many studies over the last decades, the investigated parameters were typically geared towards traditional laser driven Inertial Confinement Fusion (ICF) with densities either at 10% and above or at 1% and below the laser's critical density, electron temperatures of 3-5 keV, and laser powers near (or in excess of) 1 × 1015 W/cm2. In contrast, Magnetized Liner Inertial Fusion (MagLIF) [Slutz et al., Phys. Plasmas 17, 056303 (2010) and Slutz and Vesey, Phys. Rev. Lett. 108, 025003 (2012)] currently operates at 5% of the laser's critical density using much thicker windows (1.5-3.5 μm) than the sub-micron thick windows of traditional ICF hohlraum targets. This article describes the Pecos target area at Sandia National Laboratories using the Z-Beamlet Laser Facility [Rambo et al., Appl. Opt. 44(12), 2421 (2005)] as a platform to study laser induced pre-heat for magneto-inertial fusion targets, and the related progress for Sandia's MagLIF program. Forward and backward scattered light were measured and minimized at larger spatial scales with lower densities, temperatures, and powers compared to LPI studies available in literature.

Combined DFT and DEMS investigation of the effect of dopants in secondary zinc‐air batteries

DEFF Research Database (Denmark)

Lysgaard, Steen; Christensen, Mathias K.; Hansen, Heine A.

2018-01-01

Zinc‐air batteries offer the potential of low cost energy storage with high energy density, but at present secondary batteries suffer from poor cyclability. To develop secondary Zn‐air batteries, several challenges need to be overcome: choking of the cathode, catalyzing the oxygen evolution...... and reduction reactions, limiting dendrite formation and the hydrogen evolution reaction (HER). Understanding and alleviating HER at the anode is a challenge, where it is necessary to involve computational as well as experimental research. Here, we combine Differential Electrochemical Mass Spectrometry (DEMS......) and density functional theory calculations to investigate the fundamental role and stability over cycling of possible additives such as In, Bi and Ag. We show that both In and Bi have the desired property for a secondary battery that upon recharging, they will remain in the surface, thereby retaining...

Thermographic study of the preheating plugs in diesel engines

OpenAIRE

Royo Pastor, Rafael; Albertos Arranz, M.A.; CÁRCEL CUBAS, JUAN ANTONIO; Payá Herrero, Jorge

2012-01-01

The use of direct injection diesel engines has been widely applied during the past ten years. In such engines, the preheating plugs are a key element which has a significant contribution in the pollutant emissions. In this paper, two different plug designs from Renault are analyzed. The new plug reduces substantially the required electrical consumption. Nevertheless, the pollutant emissions are higher (fundamentally CO and HCs) and hereby a thorough analysis is required to underst...

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

Influence of declivitous secondary air on combustion characteristics of a down-fired 300-MWe utility boiler

Energy Technology Data Exchange (ETDEWEB)

Zhengqi Li; Feng Ren; Zhichao Chen; Zhao Chen; Jingjie Wang [Harbin Institute of Technology, Harbin (China). School of Energy Science and Engineering

2010-02-15

Industrial experiments were performed with a 300-MWe full-scale down-fired boiler. New data is reported for (i) gas temperature distributions within the primary air and coal mixture flows, (ii) gas compositions, such as O{sub 2}, CO, CO{sub 2} and NOx, and (iii) gas temperatures within the near-wall region. The data complements previously-obtained data from the same utility boiler before being modified by declination of the F-tier secondary air. By directing secondary air under the arches, the region where the primary air and pulverized coal mixture is ignited is brought forward within the boiler. Gas temperatures rose in the fuel-burning zone and fell in the fuel-burnout zone. As a result the quantity of unburned carbon in fly ash and the gas temperature at the furnace outlet were both lowered. 20 refs., 7 figs., 2 tabs.

A pre-heating method based on sinusoidal alternating current for lithium-ion battery

Science.gov (United States)

Fan, Wentao; Sun, Fengchun; Guo, Shanshan

2018-04-01

In this paper, a method of low temperature pre-heating of sinusoidal alternating current (SAC) is proposed. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC pre-heating method. a equivalent electric circuit(EEC) model is established to predict the heat generation rate and temperature status, whose parameters are calibrated from the EIS impedance measurements. The effects of current frequency and amplitude on the heating effect are investigated respectively. A multistep temperature-adaptive amplitude strategy is proposed and the cell can be heated from -20°C to 5°C within 509s at 100Hz frequency with this method.

Energetic, Exergetic, and Economic Analysis of MED-TVC Water Desalination Plant with and without Preheating

Directory of Open Access Journals (Sweden)

Nuri Eshoul

2018-03-01

Full Text Available Desalination is the sole proven technique that can provide the necessary fresh water in arid and semi-arid countries in sufficient quantities and meet the modern needs of a growing world population. Multi effect desalination with thermal vapour compression (MED-TVC is one of most common applications of thermal desalination technologies. The present paper presents a comprehensive thermodynamic model of a 24 million litres per day thermal desalination plant, using specialised software packages. The proposed model was validated against a real data set for a large-scale desalination plant, and showed good agreement. The performance of the MED-TVC unit was investigated using different loads, entrained vapour, seawater temperature, salinity and number of effects in two configurations. The first configuration was the MED-TVC unit without preheating system, and the second integrated the MED-TVC unit with a preheating system. The study confirmed that the thermo-compressor and its effects are the main sources of exergy destruction in these desalination plants, at about 40% and 35% respectively. The desalination plant performance with preheating mode performs well due to high feed water temperature leading to the production of more distillate water. The seawater salinity was proportional to the fuel exergy and minimum separation work. High seawater salinity results in high exergy efficiency, which is not the case with membrane technology. The plant performance of the proposed system was enhanced by using a large number of effects due to greater utilisation of energy input and higher generation level. From an economic perspective, both indicators show that using a preheating system is more economically attractive.

EFFECT OF PRE-HEAT TREATMENT ON MECHANICAL PROPERTIES OF Ti-6Al-4V WELDS

Directory of Open Access Journals (Sweden)

Gnofam Jacques TCHEIN

2016-11-01

Full Text Available The work presented here is related to the optimization of the Friction Stir Welding (FSW process. The objective is to study the influence of some parameters used in the production of welded joints by FSW. The most important parameters are the welding speed and the rotational speed of the tool. The effect of pre-heat treatment on the plates to be welded is also studied by the design of experimental methods. These pre-heat treatments result not only in a change of mechanical properties of plates to be welded, but also of their microstructure. The experiments were performed following a 16 lines fractional Taguchi table.

A study on pre-heat conditions in equivalent-dose estimation of holocene loess using single-aliquot regenerative-dose (SAR) protocol

International Nuclear Information System (INIS)

Jia Yaofeng; Huang Chunchang; Pang Jiangli; Lu Xinwei; Zhang Xu

2007-01-01

Through various arrangements of pre-heat and cut-heat temperatures in the equivalent-dose estimation of Holocene loess using a Double-SAR dating protocol, the paper estimated the equivalent-doses from several loess samples by application of IRSL and Post-IR OSL signals, respectively. The measured results present that the equivalent-dose depends on the heat temperature, especially depends on the cut-heat temperature, showing the equivalent-dose increases with the cut-heat temperature; a plateau of equivalent-dose appears at the 200-300 degree C preheat temperatures and the 200-240 degree C cut-heat temperatures, furthermore, the equivalent-doses estimated by IRSL and Post-IR OSL signals respectively are close to each other, which resulted from the similar sensitivity change directions of optical stimulated signals and their smaller change ranges in the measurement cycles using the various temperatures of pre-heat and cut-heat. This suggests that the 200-300 degree C pre-heat temperatures and the 200-240 degree C cut-heat temperatures are fit for dating young Holocene loess samples. (authors)

THE INFLUENCE OF PRE-HEAT TREATMENT ON WHITE CAST IRONS PLASTICITY

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T. M. Myronova

2013-11-01

Full Text Available Purpose. The development of heat treatment modes of white cast irons for structure changes in their eutectic constituent, namely in disturbing the monolithic structure of ledeburite colonies cementite structure and eutectic net continuity. Also the mentioned heat treatment modes are targeted to the eutectic net shift for the most suitable position from the point of plastic deforming. Methodology. The hypoeutectic white cast irons with 2.92…3.35 % carbon content and additionally alloyed by 3.18 % vanadium have been used as the research materials. The mentioned alloys have been pre-heat treated and hot twist tested. Findings. The research results showed that the carbide net breaking by plastic deforming leads to cast irons mechanical properties increasing but has difficulties in implementation due to the white cast irons low plasticity. The influence of different pre-heat treatment modes on structure and plasticity of white hypoeutectic cast irons have been investigated. They include the isotherm soaking under the different temperatures as well as multiply soakings and thermo-cycling. The influence of eutectic level, as well as pre heat treatment modes on different composition white cast irons hot plasticity have been investigated. Originality. It was determined that the heat treatment, which leads to double α→γ recrystallization under 860 – 950 °С and reperlitization under 720-680 °С results in significant increase of plasticity, as well as in un-alloyed and alloyed by vanadium white cast irons. It takes place due to carbide matrix phase separation in ledeburite colonies by new phase boundaries forming especially due to carbide transformations under vanadium alloying. Practical value. The implementation of pre-heat treatment with phase recrystallization resulted in hypoeutectic white cast irons plasticity increasing. The obtained level of cast iron plasticity corresponds to the one of carbide class steels, which ensures the successful

Techno-Economic Analysis of a Secondary Air Stripper Process

Energy Technology Data Exchange (ETDEWEB)

Heberle, J.R. [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Nikolic, Heather [Center for Applied Energy Research, University of Kentucky, Lexington, KY (United States); Thompson, Jesse [Center for Applied Energy Research, University of Kentucky, Lexington, KY (United States); Liu, Kunlei [Center for Applied Energy Research, University of Kentucky, Lexington, KY (United States); Pinkerton, Lora L. [WorleyParsons, Reading, PA (United States); Brubaker, David [WorleyParsons, Reading, PA (United States); Simpson, James C. [WorleyParsons, Reading, PA (United States); Wu, Song [Mitsubishi Hitachi Power Systems America, Inc, Basking Ridge, NJ (United States); Bhown, Abhoyjit S. [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States)

2017-08-22

We present results of an initial techno-economic assessment on a post-combustion CO2 capture process developed by the Center for Applied Energy Research (CAER) at the University of Kentucky using Mitsubishi Hitachi Power Systems’ H3-1 aqueous amine solvent. The analysis is based on data collected at a 0.7 MWe pilot unit combined with laboratory data and process simulations. The process adds a secondary air stripper to a conventional solvent process, which increases the cyclic loading of the solvent in two ways. First, air strips additional CO2 from the solvent downstream of the conventional steam-heated thermal stripper. This extra stripping of CO2 reduces the lean loading entering the absorber. Second, the CO2-enriched air is then sent to the boiler for use as secondary air. This recycling of CO2 results in a higher concentration of CO2 in the flue gas sent to the absorber, and hence a higher rich loading of the solvent exiting the absorber. A process model was incorporated into a full-scale supercritical pulverized coal power plant model to determine the plant performance and heat and mass balances. The performance and heat and mass balance data were used to size equipment and develop cost estimates for capital and operating costs. Lifecycle costs were considered through a levelized cost of electricity (LCOE) assessment based on the capital cost estimate and modeled performance. The results of the simulations show that the CAER process yields a regeneration energy of 3.12 GJ/t CO2, a $53.05/t CO2 capture cost, and LCOE of $174.59/MWh. This compares to the U.S. Department of Energy’s projected costs (Case 10) of regeneration energy of 3.58 GJ/t CO2 , a $61.31/t CO2 capture cost, and LCOE of $189.59/MWh. For H3-1, the CAER process results in a regeneration energy of 2.62 GJ/tCO2 with a stripper pressure of 5.2 bar, a capture cost of $46.93/t CO2, and an LCOE of $164.33/MWh.

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

Directory of Open Access Journals (Sweden)

M. Živković

2016-12-01

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

Microshear bond strength of preheated silorane- and methacrylate-based composite resins to dentin.

Science.gov (United States)

Demirbuga, Sezer; Ucar, Faruk Izzet; Cayabatmaz, Muhammed; Zorba, Yahya Orcun; Cantekin, Kenan; Topçuoğlu, Hüseyin Sinan; Kilinc, Halil Ibrahim

2016-01-01

The aim of this study was to investigate the effect of preheating on microshear bond strength (MSBS) of silorane and methacrylate-based composite resins to human dentin. The teeth were randomly divided into three main groups: (1) composite resins were heated upto 68 °C; (2) cooled to 4 °C; and (3) control [room temperature (RT)]. Each group was then randomly subdivided into four subgroups according to adhesive system used [Solobond M (Voco), All Bond SE (Bisco), Clearfil SE Bond (CSE) (Kuraray), Silorane adhesive system (SAS) (3M ESPE)]. Resin composite cylinders were formed (0.9 mm diameter × 0.7 mm length) and MSBS of each specimen was tested. The preheated groups exhibited the highest MSBS (p composite resins may be an alternative way to increase the MSBS of composites on dentin. © Wiley Periodicals, Inc.

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)

Zhang, Fengming; Xu, Chunyan; Zhang, Yong; Chen, Shouyan; Chen, Guifang; Ma, Chunyuan

2014-01-01

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 (TOC out ) 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

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.

X-ray emission, ablation pressure, and preheating for foils irradiated at 0. 26. mu. m wavelength

Energy Technology Data Exchange (ETDEWEB)

Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

1985-11-01

The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 ..mu..m laser at intensities approx.10/sup 15/ W cm/sup -2/ are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 ..mu..m), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant.

X-ray emission, ablation pressure, and preheating for foils irradiated at 0.26 μm wavelength

International Nuclear Information System (INIS)

Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

1985-01-01

The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 μm laser at intensities approx.10 15 W cm -2 are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 μm), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant

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)

Guan, Yipeng; Zhang, Yufeng; Sheng, Ying; Kong, Xiangrui; Du, Song

2015-01-01

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

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...

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

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section 50.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL...

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

Modification of preheated tungsten surface after irradiation at the GOL-3 facility

Energy Technology Data Exchange (ETDEWEB)

Shoshin, A.A., E-mail: shoshin@mail.ru [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Arakcheev, A.S.; Arzhannikov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Burdakov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, Novosibirsk 630092 (Russian Federation); Huber, A. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Ivanov, I.A. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Kuklin, K.N. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Polosatkin, S.V.; Postupaev, V.V.; Sinitsky, S.L. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vasilyev, A.A. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

2016-12-15

Highlights: • Preheated tungsten was irradiated at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. • The crack pattern and the quantity of bubbles depend on the initial temperatures of the target. • The orientation of major crack networks correlates with the direction of machining of the samples. • Dust impact craters were found. - Abstract: The study is devoted to tungsten surface modification after irradiation at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. In order to emulate heating with a steady plasma flux in the ITER divertor, some of the tungsten samples were preheated up to 500 °C. It was found out that the behavior of the surface modification (the crack pattern and the number of bubbles) depends on the initial temperature of the targets. While the orientation of major crack networks correlates with the direction of machining of the samples. Afterwards we have observed the process of craters’ formation caused by dust particle impacts.

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

Directory of Open Access Journals (Sweden)

Giovanni Angrisani

2016-09-01

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

Numerical simulation of the gas-solid flow in a square circulating fluidized bed with secondary air injection

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhengyang [Harbin Institute of Technology, Harbin (China). Post-doctor Station of Civil Engineering; Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Sun, Shaozeng; Zhao, Ningbo; Wu, Shaohua [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Tan, Yufei [Harbin Institute of Technology, Harbin (China). School of Municipal and Environmental Engineering

2013-07-01

The dynamic behavior of gas-solid flow in an experimental square circulating fluidized bed setup (0.25 m x 0.25 m x 6.07 m) is predicted with numerical simulation based on the theory of Euler-Euler gas-solid two-phase flow and the kinetic theory of granular flows. The simulation includes the operation cases with secondary injection and without air-staging. The pressure drop profile, local solids concentration and particle velocity was compared with experimental results. Both simulation and experimental results show that solids concentration increases significantly below the secondary air injection ports when air-staging is adopted. Furthermore, the flow asymmetry in the solid entrance region of the bed was investigated based on the particle concentration/velocity profile. The simulation results are in agreement with the experimental results qualitatively.

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

International Nuclear Information System (INIS)

Wu, Dawei; Chen, Junlong; Roskilly, Anthony P.

2015-01-01

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

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

Preheating ablation effects on the Rayleigh-Taylor instability in the weakly nonlinear regime

International Nuclear Information System (INIS)

Wang, L. F.; Ye, W. H.; He, X. T.; Sheng, Z. M.; Don, Wai-Sun; Li, Y. J.

2010-01-01

The two-dimensional Rayleigh-Taylor instability (RTI) with and without thermal conduction is investigated by numerical simulation in the weakly nonlinear regime. A preheat model κ(T)=κ SH [1+f(T)] is introduced for the thermal conduction [W. H. Ye, W. Y. Zhang, and X. T. He, Phys. Rev. E 65, 057401 (2002)], where κ SH is the Spitzer-Haerm electron thermal conductivity coefficient and f(T) models the preheating tongue effect in the cold plasma ahead of the ablation front. The preheating ablation effects on the RTI are studied by comparing the RTI with and without thermal conduction with identical density profile relevant to inertial confinement fusion experiments. It is found that the ablation effects strongly influence the mode coupling process, especially with short perturbation wavelength. Overall, the ablation effects stabilize the RTI. First, the linear growth rate is reduced, especially for short perturbation wavelengths and a cutoff wavelength is observed in simulations. Second, the second harmonic generation is reduced for short perturbation wavelengths. Third, the third-order negative feedback to the fundamental mode is strengthened, which plays a stabilization role. Finally, on the contrary, the ablation effects increase the generation of the third harmonic when the perturbation wavelengths are long. Our simulation results indicate that, in the weakly nonlinear regime, the ablation effects are weakened as the perturbation wavelength is increased. Numerical results obtained are in general agreement with the recent weakly nonlinear theories as proposed in [J. Sanz, J. Ramirez, R. Ramis et al., Phys. Rev. Lett. 89, 195002 (2002); J. Garnier, P.-A. Raviart, C. Cherfils-Clerouin et al., Phys. Rev. Lett. 90, 185003 (2003)].

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

Directory of Open Access Journals (Sweden)

Theobaldo JD

2017-05-01

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

Effect of pre-heating on the chemical oxidation efficiency: implications for the PAH availability measurement in contaminated soils.

Science.gov (United States)

Biache, Coralie; Lorgeoux, Catherine; Andriatsihoarana, Sitraka; Colombano, Stéfan; Faure, Pierre

2015-04-09

Three chemical oxidation treatments (KMnO4, H2O2 and Fenton-like) were applied on three PAH-contaminated soils presenting different properties to determine the potential use of these treatments to evaluate the available PAH fraction. In order to increase the available fraction, a pre-heating (100 °C under N2 for one week) was also applied on the samples prior oxidant addition. PAH and extractable organic matter contents were determined before and after treatment applications. KMnO4 was efficient to degrade PAHs in all the soil samples and the pre-heating slightly improved its efficiency. H2O2 and Fenton-like treatments presented low efficiency to degrade PAH in the soil presenting poor PAH availability, however, the PAH degradation rates were improved with the pre-heating. Consequently H2O2-based treatments (including Fenton-like) are highly sensitive to contaminant availability and seem to be valid methods to estimate the available PAH fraction in contaminated soils. Copyright © 2014 Elsevier B.V. All rights reserved.

Elements of a unified prognostic model for secondary air contamination by resuspension

International Nuclear Information System (INIS)

Besnus, F.; Garger, E.; Gordeev, S.; Hollaender, W.; Kashparov, V.; Martinez-Serrano, J.; Mironov, V.; Nicholson, K.; Tschiersch, J.; Vintersved, I.

1996-01-01

Based on results of several joint experimental campaigns and an extensive literature survey, a prognostic model was constructed capable of predicting airborne activity concentrations and size distributions as well as soil surface activity concentrations as a function of time and meteorological conditions. Example scenario calculations show that agricultural practices are of lesser importance to secondary air contamination than dust storms immediately after primary deposition and forest fires

The role of primary and secondary air on wood combustion in cookstoves

Science.gov (United States)

Kirch, Thomas; Birzer, Cristian H.; Medwell, Paul R.; Holden, Liam

2018-03-01

A two-stage solid fuel research furnace was used to examine the claim that through forced draught greater mixing and more complete combustion could be achieved. By varying the primary air (PA) and secondary air (SA) flow the influence on the combustion process was investigated. In the first part of the combustion, when the release of volatile compounds predominates, the variation of neither PA nor SA had a significant influence. In the second part when mainly char is oxidised an increase in both PA and SA lead to a rising nominal combustion efficiency (?)), with a greater impact observed with SA. Furthermore higher air flows caused the heat transfer, to a pot above the furnace, to decline. Therefore forced draught does lead to greater mixing and mitigation of emissions, but in the presented configuration a trade-off between a higher NCE and a lower heat transfer needs consideration.

Preheating the universe in hybrid inflation

CERN Document Server

García-Bellido, J

1998-01-01

One of the fundamental problems of modern cosmology is to explain the origin of all the matter and radiation in the Universe today. The inflationary model predicts that the oscillations of the scalar field at the end of inflation will convert the coherent energy density of the inflaton into a large number of particles, responsible for the present entropy of the Universe. The transition from the inflationary era to the radiation era was originally called reheating, and we now understand that it may consist of three different stages: preheating, in which the homogeneous inflaton field decays coherently into bosonic waves (scalars and/or vectors) with large occupation numbers; backreaction and rescattering, in which different energy bands get mixed; and finally decoherence and thermalization, in which those waves break up into particles that thermalize and acquire a black body spectrum at a certain temperature. These three stages are non-perturbative, non-linear and out of equilibrium, and we are just beginning ...

Study on the preheating duration of Cu{sub 2}SnS{sub 3} thin films using RF magnetron sputtering technique for photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Dong, Yuchen; He, Jun; Li, Xinran; Chen, Ye; Sun, Lin, E-mail: lsun@ee.ecnu.edu.cn; Yang, Pingxiong; Chu, Junhao

2016-04-25

Cu{sub 2}SnS{sub 3} (CTS) thin films are prepared by sulfurization the stacked metallic precursors deposited by raido-frequency magnetron sputtering method on molybdenum-coated soda lime glass substrates. The details of sulfurization process and the effect of preheating duration on the properties of CTS thin films have been investigated. It is found that the content of element tin strongly depend on the preheating duration. X-ray diffraction patterns identify that the CTS thin films exhibit the monoclinic structure. Raman scattering spectra make a further confirmation for the crystal structure. Fourier transform infrared reflectance spectroscopy (FTIR) is first used to study the properties of CTS thin films. The assigned active modes in Raman scattering spectra is consistent with the analysis in FTIR. Morphology analysis reveals long preheating duration would make the quality of films deteriorate. The thin film solar cell (TFSC) fabricated using the CTS absorber layer synthesized at preheating duration of 15 min shows that a power conversion efficiency up to 0.76% for a 0.19 cm{sup 2} area. The electrical characterization of CTS TFSC is first studied by electrochemical impedance spectroscopy, which implies the existence of MoS{sub x} and defects in the CTS/CdS interface. - Highlights: • CTS thin films and solar cells prepared by RF magnetron sputtering. • Preheating duration is a critical way to remain the Sn content in CTS thin film. • XRD, Raman, FTIR and XPS confirmed the single phase of CTS thin film. • The device characterization of CTS solar cell has been systematically investigated.

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

Science.gov (United States)

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

2012-10-01

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

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.

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

International Nuclear Information System (INIS)

Jolley, R.L.; Begovich, J.M.; Brashear, H.R.

1983-12-01

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 133 Xe, and 198 Au (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

Available exhaust gas power in different configurations in a pellet stove plant

Energy Technology Data Exchange (ETDEWEB)

Granada, E.; Patino, D.; Collazo, J.; Moran, J.C.; Porteiro, J. [Vigo University, E.T.S. Ingenieros Industriales, Lagoas-Marcosende, s/n, 36200 Vigo (Spain)

2009-12-15

With a view to finding the best configuration for a small cogeneration system based on the pellet combustion process, exergetic analysis was applied to a small pellet stove. The evaluation focuses on fume exergetic content for power generation purposes. Preheated air, secondary air, fume recirculation and basis configurations were studied. Global exergetic calculation was developed at these configurations based on experimental correlations of energy and emissions. The influences of the pellet feeding rate, excess air, secondary air and fume recirculation were studied. The results for multiple configurations are discussed and the best one is presented. Results show that CO emissions have a major influence on fume exergetic content, although if emissions diminish only a slight thermomechanical exergetic efficiency increase is expected. (author)

Bruce NGS A Unit 4 preheater divider plate failure

International Nuclear Information System (INIS)

Landridge, M.; McInnes, D.

1995-01-01

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

Symbiotic potential: the integration of preheating and dry cooling in cokemaking

Energy Technology Data Exchange (ETDEWEB)

Barker, J E [British Carbonization Research Association, England; Bruce, J M; Kemmetmueller, R

1978-06-01

The expression closed energy cycle has become popular in the last decade as descriptive of industrial systems in which exhaust heat is recovered from a primary energy-conversion stage and utilized either recuperatively or regeneratively within the overall complex. An old and well-proven means of utilizing the sensible heat of the incandescent coke discharged from coke ovens is known as dry cooling. This is being practiced widely in the USSR and Japan, but not yet to any significant extent in the western world. The waste heat recovered by this system is normally used to raise steam for power generation and process use. A recent advance in the carbonization of coal for the manufacture of metallurgical coke has been the application of the technique of coal drying and preheating as a means of improving both coke quality and oven productivity, and this is usually energized by burning gas as a fuel. An alternative configuration, having practical advantages in relation to efficiency of utilization of recovered energy and to safety in operation, is represented by a combination of coal drying and preheating with dry cooling of the coke. This paper is concerned with the case for this combination and the means whereby it may be effected in practice. The energy cycle of cokemaking would thus be more nearly closed.

Comparative studies on the performance and emissions of a direct injection diesel engine fueled with neem oil and pumpkin seed oil biodiesel with and without fuel preheater.

Science.gov (United States)

Ramakrishnan, Muneeswaran; Rathinam, Thansekhar Maruthu; Viswanathan, Karthickeyan

2018-02-01

In the present experimental analysis, two non-edible oils namely neem oil and pumpkin seed oil were considered. They are converted into respective biodiesels namely neem oil methyl ester (B1) and pumpkin seed oil methyl ester (B2) through transesterification process and their physical and chemical properties were examined using ASTM standards. Diesel was used as a baseline fuel in Kirloskar TV1 model direct injection four stroke diesel engine. A fuel preheater was designed and fabricated to operate at various temperatures (60, 70, and 80 °C). Diesel showed higher brake thermal efficiency (BTE) than biodiesel samples. Lower brake specific fuel consumption (BSFC) was obtained with diesel than B1 sample. B1 exhibited lower BSFC than B2 sample without preheating process. High preheating temperature (80 °C) results in lower fuel consumption for B1 sample. The engine emission characteristics like carbon monoxide (CO), hydrocarbon (HC), and smoke were found lower with B1 sample than diesel and B2 except oxides of nitrogen (NOx) emission. In preheating of fuel, B1 sample with high preheating temperature showed lower CO, HC, and smoke emission (except NOx) than B2 sample.

Development of a small air-cooled ``midnight sun'' thermophotovoltaic electric generator

Science.gov (United States)

Fraas, Lewis M.; Xiang, Huang Han; Hui, She; Ferguson, Luke; Samaras, John; Ballantyne, Russ; Seal, Michael; West, Ed

1996-02-01

A natural gas fired thermophotovoltaic generator using infrared-sensitive GaSb cells and a silicon carbide emitter is described. The emitter is designed to operate at 1400 °C. Twelve GaSb receivers surround the emitter. Each receiver contains a string of series connected cells. Special infrared filters are bonded to each cell. These filters transmit short wavelength useful IR to the cells while reflecting longer wavelength IR back to the emitter. Combustion air is supplied to the burner through a counterflow heat exchanger where the air is preheated by the exhaust from the burner. The unit is air cooled and designed to produce approximately 100 Watts of electric power.

Investigation of a hybrid PVT air collector system

Science.gov (United States)

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

2017-02-01

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

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

NARCIS (Netherlands)

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

2008-01-01

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

Non-Gaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation

Science.gov (United States)

Barnaby, Neil; Cline, James M.

2006-05-01

We show that in hybrid inflation it is possible to generate large second-order perturbations in the cosmic microwave background due to the instability of the tachyonic field during preheating. We carefully calculate this effect from the tachyon contribution to the gauge-invariant curvature perturbation, clarifying some confusion in the literature concerning nonlocal terms in the tachyon curvature perturbation; we show explicitly that such terms are absent. We quantitatively compute the non-Gaussianity generated by the tachyon field during the preheating phase and translate the experimental constraints on the nonlinearity parameter fNL into constraints on the parameters of the model. We also show that nonscale-invariant second-order perturbations from the tachyon field with spectral index n=4 can become larger than the inflaton-generated first-order perturbations, leading to stronger constraints than those coming from non-Gaussianity. The width of the excluded region in terms of the logarithm of the dimensionless coupling g, grows linearly with the log of the ratio of the Planck mass to the tachyon VEV, log⁡(Mp/v); hence very large regions are ruled out if the inflationary scale v is small. We apply these results to string-theoretic brane-antibrane inflation, and find a stringent upper bound on the string coupling, gs<10-4.5.

Methodology for estimation of secondary meteorological variables to be used in local dispersion of air pollutants

International Nuclear Information System (INIS)

Turtos, L.; Sanchez, M.; Roque, A.; Soltura, R.

2003-01-01

Methodology for estimation of secondary meteorological variables to be used in local dispersion of air pollutants. This paper include the main works, carried out into the frame of the project Atmospheric environmental externalities of the electricity generation in Cuba, aiming to develop methodologies and corresponding software, which will allow to improve the quality of the secondary meteorological data used in atmospheric pollutant calculations; specifically the wind profiles coefficient, urban and rural mixed high and temperature gradients

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

Science.gov (United States)

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

2001-07-01

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

Measuring skin necrosis in a randomised controlled feasibility trial of heat preconditioning on wound healing after reconstructive breast surgery: study protocol and statistical analysis plan for the PREHEAT trial.

Science.gov (United States)

Cro, Suzie; Mehta, Saahil; Farhadi, Jian; Coomber, Billie; Cornelius, Victoria

2018-01-01

Essential strategies are needed to help reduce the number of post-operative complications and associated costs for breast cancer patients undergoing reconstructive breast surgery. Evidence suggests that local heat preconditioning could help improve the provision of this procedure by reducing skin necrosis. Before testing the effectiveness of heat preconditioning in a definitive randomised controlled trial (RCT), we must first establish the best way to measure skin necrosis and estimate the event rate using this definition. PREHEAT is a single-blind randomised controlled feasibility trial comparing local heat preconditioning, using a hot water bottle, against standard care on skin necrosis among breast cancer patients undergoing reconstructive breast surgery. The primary objective of this study is to determine the best way to measure skin necrosis and to estimate the event rate using this definition in each trial arm. Secondary feasibility objectives include estimating recruitment and 30 day follow-up retention rates, levels of compliance with the heating protocol, length of stay in hospital and the rates of surgical versus conservative management of skin necrosis. The information from these objectives will inform the design of a larger definitive effectiveness and cost-effectiveness RCT. This article describes the PREHEAT trial protocol and detailed statistical analysis plan, which includes the pre-specified criteria and process for establishing the best way to measure necrosis. This study will provide the evidence needed to establish the best way to measure skin necrosis, to use as the primary outcome in a future RCT to definitively test the effectiveness of local heat preconditioning. The pre-specified statistical analysis plan, developed prior to unblinded data extraction, sets out the analysis strategy and a comparative framework to support a committee evaluation of skin necrosis measurements. It will increase the transparency of the data analysis for the

The secondary electron yield of air exposed metal surfaces at the example of niobium

CERN Document Server

Scheuerlein, C; Taborelli, M

2002-01-01

The secondary electron yield (SEY) variation of atomically clean metal surfaces due to air exposures and during subsequent heat treatments is described with the example of a sputter-deposited Nb thin film. Corresponding variations of the surface chemical composition have been monitored using AES and SSIMS. On the basis of these results and of previously obtained SEY results on metals and metal oxides the origin of the SEY variations is discussed. The SEY increase, which is generally observed during long lasting air exposures of clean metals, is mainly caused by the adsorption of an airborne carbonaceous contamination layer. The estimated value of about 3 for the maximum SEY of this layer is higher than that of all pure metals. Only in some cases the air-formed oxide can contribute to the air exposure induced SEY increase while many oxides have a lower SEY than their parent metals. From the experimental data it can also be excluded that the SEY increase during air exposures is mainly due to an increased second...

Preheating of manure utilizing heat exchanger and flue gas. Forvarmning af gylle ved varmeveksling med roeggas

Energy Technology Data Exchange (ETDEWEB)

Weber, J.

1987-07-15

It has been shown that preheating of manures in biomass conversion plants to a temperature of 50-60 deg. C, before the anaerobic digestion takes place at a temperature of 35-45 deg. C, results in an increase of methane production. But the method normally involves an increase in energy consumption. The aim of the project was to develope methods of utilizing heat from flue gas emitted from the boiler connected to the plant, with the help of a heat exchanger. The heat thus recovered would be used to preheat the manure. The chosen method was to inject the flue gas directly into the manure mass, following this up with heat exchanging and condensing. In order to mix the flue gas thoroughly into the manure an ejector was used, this was driven by the manure flow. Results were satisfactory. (AB).

Effect of bond coat and preheat on the microstructure, hardness, and porosity of flame sprayed tungsten carbide coatings

Science.gov (United States)

Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

2017-06-01

Thermally sprayed coatings are used to improve the surface properties of tool steel materials. Bond coatings are commonly used as intermediate layers deposited on steel substrates (i.e. H13 tool steel) before the top coat is applied in order to enhance a number of critical performance criteria including adhesion of a barrier coating, limiting atomic migration of the base metal, and corrosion resistance. This paper presents the experimental results regarding the effect of nickel bond coat and preheats temperatures (i.e. 200°C, 300°C and 400°C) on microstructure, hardness, and porosity of tungsten carbide coatings sprayed by flame thermal coating. Micro-hardness, porosity and microstructure of tungsten carbide coatings are evaluated by using micro-hardness testing, optical microscopy, scanning electron microscopy, and X-ray diffraction. The results show that nickel bond coatings reduce the susceptibility of micro crack formation at the bonding area interfaces. The percentage of porosity level on the tungsten carbide coatings with nickel bond coat decreases from 5.36 % to 2.78% with the increase of preheat temperature of the steel substrate of H13 from 200°C to 400°C. The optimum hardness of tungsten carbide coatings is 1717 HVN in average resulted from the preheat temperature of 300°C.

Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire

International Nuclear Information System (INIS)

Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

2004-01-01

The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs

Experimental and analytical evaluation of preheating temperature during multipass repair welding

Directory of Open Access Journals (Sweden)

Sedmak Aleksandar S.

2017-01-01

Full Text Available Experimental measurement and analytical calculation of preheating, i. e. interpass temperature during multi-pass repair welding has been presented. Analytical calculation is based on heat transfer analysis, whereas measurements have been performed by thermovision camera. Repair welding was performed on crane wheels in the Steelworks Smederevo. Comparison of results indicated that analytical calculation is good enough as the first approximation, but it needs further elaboration, e. g. taking into account the radiation component of heat dissipation and/or temperature dependence of material thermomechanical properties.

Gravitational waves from Abelian gauge fields and cosmic strings at preheating

International Nuclear Information System (INIS)

Dufaux, Jean-Francois; Figueroa, Daniel G.; Garcia-Bellido, Juan

2010-01-01

Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space. We show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearance of new peaks at characteristic frequencies that are related to the mass scales in the problem. We also show how these new features in the spectra correlate with stringlike spatial configurations in both the Higgs and gauge fields that arise due to the appearance of topological winding numbers of the Higgs around Nielsen-Olesen strings. We study in detail the time evolution of the spectrum of gauge fields and gravitational waves as these strings evolve and decay before entering a turbulent regime where the gravitational wave energy density saturates.

A New Laser Preheat Protocol For Maglif

Science.gov (United States)

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

2017-10-01

Previous Magnetized Liner Inertial Fusion experiments at Sandia National Labs have preheated the fuel with the unsmoothed 2 ω Z-Beamlet Laser. A new low intensity laser configuration, using phase plate smoothing and a low-power pulse shape, improved laser propagation and reduced stimulated Brillouin scattering in offline laser experiments. This allows for more efficient use of laser energy and better spot reproducibility. The new laser protocol is estimated to couple at least 650 J to the fuel, sufficient to produce comparable neutron yields with the previous unsmoothed configuration. Mid-Z dopants were also fielded on the underside of the window. Observation of these dopants provided evidence of window material mixing into the fuel with both the unsmoothed and smoothed beam, consistent with MHD simulation predictions. Sandia National Laboratories is a multi-mission laboratory managed and operated by NTESS, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOE's NNSA under contract DE-NA0003525.

Photochemical age of air pollutants, ozone, and secondary organic aerosol in transboundary air observed on Fukue Island, Nagasaki, Japan

Science.gov (United States)

Irei, Satoshi; Takami, Akinori; Sadanaga, Yasuhiro; Nozoe, Susumu; Yonemura, Seiichiro; Bandow, Hiroshi; Yokouchi, Yoko

2016-04-01

To better understand the secondary air pollution in transboundary air over westernmost Japan, ground-based field measurements of the chemical composition of fine particulate matter ( ≤ 1 µm), mixing ratios of trace gas species (CO, O3, NOx, NOy, i-pentane, toluene, and ethyne), and meteorological elements were conducted with a suite of instrumentation. The CO mixing ratio dependence on wind direction showed that there was no significant influence from primary emission sources near the monitoring site, indicating long- and/or mid-range transport of the measured chemical species. Despite the considerably different atmospheric lifetimes of NOy and CO, these mixing ratios were correlated (r2 = 0.67). The photochemical age of the pollutants, t[OH] (the reaction time × the mean concentration of OH radical during the atmospheric transport), was calculated from both the NOx / NOy concentration ratio (NOx / NOy clock) and the toluene / ethyne concentration ratio (hydrocarbon clock). It was found that the toluene / ethyne concentration ratio was significantly influenced by dilution with background air containing 0.16 ppbv of ethyne, causing significant bias in the estimation of t[OH]. In contrast, the influence of the reaction of NOx with O3, a potentially biasing reaction channel on [NOx] / [NOy], was small. The t[OH] values obtained with the NOx / NOy clock ranged from 2.9 × 105 to 1.3 × 108 h molecule cm-3 and were compared with the fractional contribution of the m/z 44 signal to the total signal in the organic aerosol mass spectra (f44, a quantitative oxidation indicator of carboxylic acids) and O3 mixing ratio. The comparison of t[OH] with f44 showed evidence for a systematic increase of f44 as t[OH] increased, an indication of secondary organic aerosol (SOA) formation. To a first approximation, the f44 increase rate was (1.05 ± 0.03) × 10-9 × [OH] h-1, which is comparable to the background-corrected increase rate observed during the New England Air Quality

Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-Ray Preheat

International Nuclear Information System (INIS)

Colvin, Jeffrey D.; Kalantar, Daniel H.

2006-01-01

To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<1013 W/cm2, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flash-coating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat

International Nuclear Information System (INIS)

Colvin, J D; Kalantar, D H

2005-01-01

To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, 13 W/cm 2 , compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

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

Directory of Open Access Journals (Sweden)

T. Wang

2010-08-01

Full Text Available This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NO_x and volatile organic compounds (VOCs at an urban site dropped by 25% and 20–45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM_2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions. A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34–88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv, indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO₂, total sulfur (SO₂+PM_2.5 sulfate, carbon monoxide (CO, reactive aromatics (toluene and xylenes sharply decreased (by 8–64% in 2008, but no significant changes were observed for the concentrations of

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

DEFF Research Database (Denmark)

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

2003-01-01

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

Reheating the D-brane universe via instant preheating

International Nuclear Information System (INIS)

Panda, Sudhakar; Sami, M.; Thongkool, I.

2010-01-01

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 10 8 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.

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

Science.gov (United States)

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

2017-03-15

PM10 from a suburban site in the northwest of Spain was assessed using data from chemical determinations, meteorological parameters, aerosol maps and five-day back trajectories of air masses. Temporal variations in the chemical composition of PM10 were subsequently related to stationary/mobile local sources and long-range transport stemming from Europe and North Africa. The presence of secondary inorganic species (sulphates, nitrates and ammonium) in airborne particulate matter constituted one of the main focuses of this study. These chemical species formed 16.5% of PM10 on average, in line with other suburban background sites in Europe. However, a maximum of 47.8% of PM10 were recorded after several days under the influence of European air masses. Furthermore, the highest values of these three chemical species coincided with episodes of poor air circulation and influxes of air masses from Europe. The relationship between SO 4 2- and NH 4 + (R 2  = 0.57, p-valueforest fires. On isolated days, combustion was estimated to contribute up to 21.0 μg PM/m 3 (50.8% of PM10). The contribution from industrial processes to this source is also worth highlighting given the presence of Ni and Co in its profile. Furthermore, African dust outbreaks at the sampling site, characterised by an arc through the Atlantic Ocean, were usually associated with a higher concentration of Al 2 O 3 in PM10. Results evidenced the relevance of stationary (i.e., steelworks and thermal power station) and mobile sources in the air quality at the suburban site under study, with important apportionments of particulate matter coming from road traffic and as consequence of releasing precursor gases of secondary particles to the atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reducing the effects of X-ray pre-heat in double shell NIF capsules by over-coating the high Z shell

Science.gov (United States)

Wilson, Douglas; Milovich, J. L.; Daughton, W. S.; Loomis, E. N.; Sauppe, J. P.; Dodd, E. S.; Merritt, E. C.; Montgomery, D. S.; Renner, D. B.; Haines, B. M.; Cardenas, T.; Desjardins, T.; Palaniyappan, S.; Batha, S. H.

2017-10-01

Hohlraum generated X-rays will penetrate the ablator of a double shell capsule and be absorbed in the outer surface of the inner capsule. The ablative pressure this generates drives a shock into the central fuel, and a reflected shock that reaches the inner high-Z shell surface before the main shock even enters the fuel. With a beryllium over-coat preheat X-rays deposit just inside the beryllium/high z interface. The beryllium tamps the preheat expansion, eliminating ablation, and dramatically reducing pressure. The slow shock or pressure wave it generates is then overtaken by the main shock, avoiding an early shock in the fuel and increasing capsule yield.

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

DEFF Research Database (Denmark)

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

2003-01-01

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

Ways to achieve optimum utilization of waste gas heat in cement kiln plants with cyclone preheaters

Energy Technology Data Exchange (ETDEWEB)

Steinbiss, E

1986-02-01

Kiln exit gases and the exhaust gases from clinker coolers often cannot be fully utilized in drying plants. In such cases a part of the heat content of the gases should be utilized for water heating. In addition, it is possible to utilize the waste gas heat in conventional steam boilers, with which, depending on design, it is possible to generate electricity at a rate of between 10-30 kWh/t (net output). A new and promising method of utilization of waste gas heat is provided by precalcining systems with bypass, in which up to 100% of the kiln exit gases can be economically bypassed and be utilized in a steam boiler, without requiring any cooling. A development project, already started, gives information on the operational behaviour of such a plant and on the maximum energy recoverable. Alternatively, the bypass gases may, after partial cooling with air or preheater exit gas, be dedusted and then utilized in a grinding/drying plant. Furthermore, they can be used in the cement grinding process for the drying of wet granulated blastfurnace slag or other materials. For this it is not necessary to dedust the bypass gases.

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-03-15

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

Effects of secondary containment air cleanup system leakage on the accident offsite dose as determined during preop tests of the Sequoyah Nuclear Plant

International Nuclear Information System (INIS)

Klaes, L.J.; Nass, S.A.; Proctor, L.D.

1981-01-01

The Sequoyah Nuclear Plant has two secondary containments. One is the annular region between the primary containment and the shield building surrounding the primary containment. The second is the auxiliary building secondary containment enclosure which is potentially subject to direct airborne radioactivity. Two air cleanup systems are provided to serve these areas. The emergency gas treatment system (EGTS) serves the annulus between the primary containment and the shield building, and the auxiliary building gas treatment system (ABGTS) serves the area inside of the auxiliary building secondary containment enclosure. The major function served by these air cleanup systems is that of controlling and processing airborne contamination released in these areas during any accident up to a design basis accident. This is accomplished by (1) creating a negative pressure in the areas served to ensure that no unprocessed air is released to the atmosphere, (2) providing filtration units to process all air exhausted from the secondary containment spaces, and (3) providing a low-leakage enclosure to limit exhaust flows. Offsite dose effects due to secondary containment release rates, bypass leakage, and duct and damper leakages are presented and parameter variations are considered. For the EGTS, a recirculation system, the most important parameter is the total inleakage of the system which causes an increase in both whole body (gamma) and thyroid (iodine) doses. For the ABGTS, a once-through system, the most important paramter is the inleakage which bypasses the filters resulting in an increase in the thyroid dose only. Actual preoperational test data are utilized. Problems encountered during the preop test are summarized. Solutions incorporated to bring the EGTS and ABGTS air cleanup systems within the test acceptance criteria required to meet offsite dose limitations are discussed and the resultant calculated offsite dose is presented

Process and apparatus for emissions reduction from waste incineration

International Nuclear Information System (INIS)

Khinkis, M.J.; Abbasi, H.A.; Lisauskas, R.A.; Itse, D.C.

1991-01-01

This paper describes a process for waste combustion. It comprises: introducing the waste into a drying zone within a combustion chamber; supplying air to the drying zone for preheating, drying, and partially combusting the waste; advancing the waste to a combustion zone within the combustion chamber; supplying air to the combustion zone for further advancing the waste to a burnout zone with the combustion chamber; supplying air to the burnout zone for final burnout of organics in the waste; and injecting fuel and recirculated glue gases into the combustion chamber above the waste to create a reducing secondary combustion zone

Useful work and the thermal efficiency in the ideal Lenolr cycle with regenerative preheating

Science.gov (United States)

Georgiou, Demos P.

2000-11-01

In the existing thermal engine concepts negative work transfer (usually needed to drive a compression process) is supplied by the work produced by the engine itself. The remaining difference (i.e., the net work transfer) becomes the useful work, since it is available for external consumption. The thermal efficiency is the parameter that compares this against the heat input into the system. It forms the main optimization parameter in any engine design. The objective of the present study is to show that for the case of the Lenoir cycle with regenerative preheating the entire positive work is available for external consumption, since the negative (i.e., the compression) work is supplied by the atmospheric air. Not only this, but, during the compression process and due to the pressure difference across the two sides of the moving piston, an additional (useful) work transfer may be generated. Thus, the proposed power plant may be considered as a combination of a thermal engine and a wind turbine. In the ideal cycle limit (at least), the total amount of useful work exceeds the heat entering the system. This leads to the definition of a new parameter for the efficiency (called the technical efficiency), which compares the combined positive work transfer (i.e., the useful one) against the heat entering the system and which may exceed the 100% level.

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

Science.gov (United States)

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

2017-07-01

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

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

Science.gov (United States)

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

Effect of preheat repetition on color stability of methacrylate- and silorane-based composite resins.

Science.gov (United States)

Abed Kahnamouei, Mehdi; Gholizadeh, Sarah; Rikhtegaran, Sahand; Daneshpooy, Mehdi; Kimyai, Soodabeh; Alizadeh Oskoee, Parnian; Rezaei, Yashar

2017-01-01

Background. The aim of this study was to investigate the effect of preheating methacrylate- and silorane-based composite resins on their color stability up to 40 times at 55‒60°C. Methods. Seventy-six methacrylate and silorane-based composite resin samples, with a diameter of 10 mm and a height of 2 mm, were divided into 4 groups (n=19). After the samples were prepared, their color parameters were determined using a reflective spectrophotometer. The composite resin samples were separately stored in a solution of tea for 40 consecutive days. Then the samples underwent a color determination procedure again using a spectrophotometer and color changes were recorded. Finally two-way ANOVA was used to study the effect of composite temperature on its staining (Pcomposite resin samples compared to non-heated samples at P=0.005 and P=0.029 for silorane-based and Z250 composite resin samples, respectively. Results. Both composite resin type (P=0.014) and preheating (Pcomposite resin samples, up to 55‒60°C for 40 rounds, resulted in more color changes compared with unheated composite resin samples. After storage in a solution of tea the color change rate in the composite resin samples of silorane-based was higher than the Z250 composite resin samples.

Variability of Atmospheric Radon-222 and Secondary Aerosol Components in Accordance with Air Mass Transport Pathways at Jeju Island, Korea, during 2011-2014

International Nuclear Information System (INIS)

Bu, Jun-Oh; Song, Jung-Min; Kim, Won-Hyung; Kang, Chang-Hee; Chambers, Scott D.; Williams, Alastair G.; Lee, Chulkyu

2016-01-01

Real-time monitoring of hourly atmospheric Radon-222 concentration and three daily monitoring of the secondary aerosol components of PM_1_0 were performed throughout 2011-2014 at Gosan station, Jeju Island, in order to characterize their background levels and temporal variation. The annual mean radon and PM_1_0 mass concentrations were 2326 ± 1198 mBq/m"3 and 37.1 ± 19.5 μg/m"3, respectively. Based on cluster analyses of air mass back trajectories, the frequencies of air masses originating from continental China, the Korean Peninsula, and North Pacific Ocean routes were 53, 28, and 19%, respectively. When the air masses were transported to Jeju Island from continental China, the concentrations of radon and secondary aerosol components (nss-SO_4"2"-, NO_3"-, NH_4"+) were relatively high: 2577 mBq/m"3 and 14.4 μg/m"3, respectively. In cases when the air masses have moved from the Korean Peninsula, the corresponding concentrations were 2247 mBq/m"3 and 11.4 μg/m"3, respectively. On the other hand, when the air masses came from the North Pacific Ocean, their radon and secondary aerosol concentrations decreased much further, 1372 mBq/m"3 and 10.5 μg/m"3, respectively. Consequently, the variability of atmospheric radon concentrations at Gosan station might be characterized by synoptic changes in air mass fetch as well as diurnal changes in atmospheric mixing depth.

A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

Energy Technology Data Exchange (ETDEWEB)

Huang Kejin [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: huangkj@mail.buct.edu.cn; Shan Lan; Zhu Qunxiong [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Qian Jixin [School of Information Science and Technology, Zhejiang University, Zhejiang 300027 (China)

2008-06-15

An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC.

A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

International Nuclear Information System (INIS)

Huang Kejin; Shan Lan; Zhu Qunxiong; Qian Jixin

2008-01-01

An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC

Pretreatment and preheating of scrap. Tarkastelu koskien romun esikaesittely- ja esikuumennusmenetelmiae

Energy Technology Data Exchange (ETDEWEB)

Hooli, P.; Hanni, J. (Outokumpu Oy Tornion Tehtaat, Tornio (Finland))

1990-01-01

As a background for this study has been those demands for scrap treatments and transportation, which are coming with increasing production of melting shop of Outokumpu Oy's Tornio works and also problems caused by snow among productionrate. Different pretreatment-, transport-, and preheatingmethods and some alternatives has been studied to arrange those as a functioning complete. Also very exact plannings for some pretreatmentmethods has been made. From preheatingmethods some methods, which are concerned to be effective and possible in the future has been studied. In addition those parameters, which are involved to the effectivity of preheating process in melting shop of Outokumpu Oy's Tornio works has been examined.

Pretreatment and preheating of scrap; Tarkastelu koskien romun esikaesittely- ja esikuumennusmenetelmiae

Energy Technology Data Exchange (ETDEWEB)

Hooli, P.; Hanni, J. [Outokumpu Oy Tornion Tehtaat, Tornio (Finland)

1990-12-31

As a background for this study has been those demands for scrap treatments and transportation, which are coming with increasing production of melting shop of Outokumpu Oy`s Tornio works and also problems caused by snow among productionrate. Different pretreatment-, transport-, and preheatingmethods and some alternatives has been studied to arrange those as a functioning complete. Also very exact plannings for some pretreatmentmethods has been made. From preheatingmethods some methods, which are concerned to be effective and possible in the future has been studied. In addition those parameters, which are involved to the effectivity of preheating process in melting shop of Outokumpu Oy`s Tornio works has been examined.

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

DEFF Research Database (Denmark)

Jungner, H.; Bøtter-Jensen, L.

1994-01-01

and as a result, the equivalent dose (ED) would be underestimated. A study of sensitivity changes in feldspars and quartz was carried out with emphasis on the effect of preheat and annealing on the OSL signal. Measurement results obtained are presented, and possible elimination of errors in dating caused...

Performance evaluation of a state-of-the-art solar air-heating system with auxiliary heat pump

Science.gov (United States)

1980-01-01

The system in Solar House 2 consists of 57.9 sq. m. of Solaron Series 300 Collectors, 10.3 cu. m. 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. Since all components of the system are commercially available the system is considered to be a state of the art solar air-heating system. The system design is one that is recommended for residential and small office buildings.

Photochemical age of air pollutants, ozone, and secondary organic aerosol in transboundary air observed on Fukue Island, Nagasaki, Japan

Directory of Open Access Journals (Sweden)

S. Irei

2016-04-01

Full Text Available To better understand the secondary air pollution in transboundary air over westernmost Japan, ground-based field measurements of the chemical composition of fine particulate matter ( ≤  1 µm, mixing ratios of trace gas species (CO, O3, NOx, NOy, i-pentane, toluene, and ethyne, and meteorological elements were conducted with a suite of instrumentation. The CO mixing ratio dependence on wind direction showed that there was no significant influence from primary emission sources near the monitoring site, indicating long- and/or mid-range transport of the measured chemical species. Despite the considerably different atmospheric lifetimes of NOy and CO, these mixing ratios were correlated (r2 = 0.67. The photochemical age of the pollutants, t[OH] (the reaction time  ×  the mean concentration of OH radical during the atmospheric transport, was calculated from both the NOx ∕ NOy concentration ratio (NOx ∕ NOy clock and the toluene ∕ ethyne concentration ratio (hydrocarbon clock. It was found that the toluene / ethyne concentration ratio was significantly influenced by dilution with background air containing 0.16 ppbv of ethyne, causing significant bias in the estimation of t[OH]. In contrast, the influence of the reaction of NOx with O3, a potentially biasing reaction channel on [NOx] / [NOy], was small. The t[OH] values obtained with the NOx ∕ NOy clock ranged from 2.9  ×  105 to 1.3  ×  108 h molecule cm−3 and were compared with the fractional contribution of the m∕z 44 signal to the total signal in the organic aerosol mass spectra (f44, a quantitative oxidation indicator of carboxylic acids and O3 mixing ratio. The comparison of t[OH] with f44 showed evidence for a systematic increase of f44 as t[OH] increased, an indication of secondary organic aerosol (SOA formation. To a first approximation, the f44 increase rate was (1.05 ± 0.03  ×  10−9�

Resistive vs. total power depositions by Alfven modes in pre-heated low aspect ratio tokamaks

International Nuclear Information System (INIS)

Cuperman, S.; Bruma, C.; Komoshvili, K.

2004-01-01

The power deposition of fast waves launched by a LFS located antenna in a pre-heated, strongly non-uniform low aspect ratio tokamak (START) is investigated. The rigorous computational results indicate a total power deposition by far larger than that predicted for Alfven continuum eigenmodes in cylindrical plasmas. For toroidal wave numbers |N| > 1, the resistive and total power depositions are almost equal. (author)

Solar air heating system for combined DHW and space heating

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Bosanac, M.

2002-12-01

The project deals with the development and testing of a simple system for utilization of the summer excess heat from small solar air heating systems for preheating of fresh air. The principle of the system is to lead the heated air down around a domestic hot water tank letting the surface of the tank act as heat exchanger between the air and the water. In order to increase the heat transfer, coefficient fins into the air stream were mounted on the tank. A complete system with 3 m{sup 2} solar air collector, ductworks and a 85 litre storage were set up and extensively monitored. The air stream through the system was created by a fan connected directly to one or two PV-panels leading to a solar radiation dependent flow rate without the use of any other control. Based on monitoring results the system was characterized and a TRNSYS model of the system was developed and calibrated/validated. The monitoring and the simulations with the TRNSYS model revealed several interesting things about the system. The monitoring revealed that the system is capable of bringing the temperature of the water in the storage above 60 deg. C at warm days with clear sky conditions. The storage is very stratified, which is beneficial as usable hot water temperatures rather quickly are obtained. The performance was highly dependent on the airflow rate through the system. It can be concluded that the investigated system will have a performance in the order of 500 kWh during the winter, spring and autumn months and around 250 kWh during the four summer months - or in total a yearly performance of 750 kWh/m{sup 2}. A small traditional solar heating system for preheating of domestic hot water would have a higher performance during the four summer months, but no performance during the rest of the year if the system is installed in a summer house, which only is occupied during the summer. The parametric analysis further indicates that it is possible to further optimise the system when the thermal

Variability of Atmospheric Radon-222 and Secondary Aerosol Components in Accordance with Air Mass Transport Pathways at Jeju Island, Korea, during 2011-2014

Energy Technology Data Exchange (ETDEWEB)

Bu, Jun-Oh; Song, Jung-Min; Kim, Won-Hyung; Kang, Chang-Hee [Jeju National University, Jeju (Korea, Republic of); Chambers, Scott D.; Williams, Alastair G. [Australian Nuclear Science and Technology Organisation, Kirrawee DC (Australia); Lee, Chulkyu [Korea Meteorological Administration, Seoul (Korea, Republic of)

2016-06-15

Real-time monitoring of hourly atmospheric Radon-222 concentration and three daily monitoring of the secondary aerosol components of PM{sub 10} were performed throughout 2011-2014 at Gosan station, Jeju Island, in order to characterize their background levels and temporal variation. The annual mean radon and PM{sub 10} mass concentrations were 2326 ± 1198 mBq/m{sup 3} and 37.1 ± 19.5 μg/m{sup 3}, respectively. Based on cluster analyses of air mass back trajectories, the frequencies of air masses originating from continental China, the Korean Peninsula, and North Pacific Ocean routes were 53, 28, and 19%, respectively. When the air masses were transported to Jeju Island from continental China, the concentrations of radon and secondary aerosol components (nss-SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +}) were relatively high: 2577 mBq/m{sup 3} and 14.4 μg/m{sup 3}, respectively. In cases when the air masses have moved from the Korean Peninsula, the corresponding concentrations were 2247 mBq/m{sup 3} and 11.4 μg/m{sup 3}, respectively. On the other hand, when the air masses came from the North Pacific Ocean, their radon and secondary aerosol concentrations decreased much further, 1372 mBq/m{sup 3} and 10.5 μg/m{sup 3}, respectively. Consequently, the variability of atmospheric radon concentrations at Gosan station might be characterized by synoptic changes in air mass fetch as well as diurnal changes in atmospheric mixing depth.

Start-up emissions from residential down-draught wood log boilers

Energy Technology Data Exchange (ETDEWEB)

Pettersson, E. (Luleaa Univ. of Technology (Sweden). Energy Technology Centre in Piteaa), Email: esbjorn.pettersson@ltu.se

2009-07-01

Start-up emissions can be substantial and even dominating in real use. There are few published investigations regarding the relative importance of different parameters on the start-up emissions. It has though recently been stated that for down-draught boilers, best results are achieved if the wood charge is ignited fairly close to the secondary chamber. The objective of the experimental work was to evaluate the effect of different fuel and design parameters on the start-up emissions, using experimental design which enables a direct comparison between different parameters, using three levels of preheating of secondary air, electric preheating of primary air, different moisture and size of the start wood as well as different amounts of birch bark, which was used to spread the fire during the start. The boiler did not use a bypass damper and the full fuel charge was added before igniting the start wood through an ignition door situated slightly above the grate. The only significant results for the four parameters were that smaller and drier start wood gave lower start-up emissions. Extra amount of birch bark gave the same result. The most important parameters are the fuel parameters, which mean that the result is generally applicable. (orig.)

Air solar collectors in building use - A review

Science.gov (United States)

Bejan, Andrei-Stelian; Labihi, Abdelouhab; Croitoru, Cristiana; Catalina, Tiberiu

2018-02-01

In the current energy and environmental context it is imperative to implement systems based on renewable energy sources in order to reduce energy consumptions worldwide. Solar collectors are studied by many years and many researchers are focusing their attention in order to increase their efficiency and cost-effectiveness. Water solar collectors are often implemented for domestic hot water, heating or industrial processes and already have a place on the market. A promising system which is not yet widely known is represented by air solar collectors that could represent an efficient way to use the solar energy with a lower investment cost, a system that can be used in order to preheat the fresh air required for heating, drying, or to maintain a minimum temperature during winter. This paper presents a comprehensive literature review on air solar collectors used mainly in buildings, acting as a solar wall. Air solar collectors are roughly classified into two types: glazed and opaque. The present study comprises the solar collector classification, applications and their main parameters with a special focus on opaque solar collectors.

Air solar collectors in building use - A review

Directory of Open Access Journals (Sweden)

Bejan Andrei-Stelian

2018-01-01

Full Text Available In the current energy and environmental context it is imperative to implement systems based on renewable energy sources in order to reduce energy consumptions worldwide. Solar collectors are studied by many years and many researchers are focusing their attention in order to increase their efficiency and cost-effectiveness. Water solar collectors are often implemented for domestic hot water, heating or industrial processes and already have a place on the market. A promising system which is not yet widely known is represented by air solar collectors that could represent an efficient way to use the solar energy with a lower investment cost, a system that can be used in order to preheat the fresh air required for heating, drying, or to maintain a minimum temperature during winter. This paper presents a comprehensive literature review on air solar collectors used mainly in buildings, acting as a solar wall. Air solar collectors are roughly classified into two types: glazed and opaque. The present study comprises the solar collector classification, applications and their main parameters with a special focus on opaque solar collectors.

Solar project description for Helio-Thermics, Inc., lot 6 single family residence; Greenville, South Carolina

Science.gov (United States)

Moore, D.

1981-03-01

An instrumented single family residence in Greenville, South Carolina, has approximately 1086 square feet on conditioned space. Solar energy is used for space heating the home and preheating domestic and water (DHW). Solar energy enters the attic through a 416 square foot aperture which is double glazed with corrugated, translucent, fiberglass reinforced, acrylic panels. Warm air accumulates in the peak of the attic roof and circulates through the conditioned space or through storage by an air handler. Solar energy is stored in an 870 cubic foot storage bin containing 85,460 pounds of crushed rock located under the house. cold water is preheated in the attic by thermosiphoning water from the 80 gallon preheat tank through a manifold system of copper tubes. These tubes are attached to black sheet metal plates. Preheated city water is stored in the preheat tank and supplied, on demand, to a conventional 80 gallon DHW tank. When solar energy is insufficient to satisfy the space heating load, a water to air heat exchanger in the hot air supply duct provides auxiliary energy for space heating. A gas fired water heater provides auxiliary energy for the water to air heat exchanger and the DHW.

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-07-01

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

Coal fired air turbine cogeneration

Science.gov (United States)

Foster-Pegg, R. W.

Fuel options and generator configurations for installation of cogenerator equipment are reviewed, noting that the use of oil or gas may be precluded by cost or legislation within the lifetime of any cogeneration equipment yet to be installed. A coal fueled air turbine cogenerator plant is described, which uses external combustion in a limestone bed at atmospheric pressure and in which air tubes are sunk to gain heat for a gas turbine. The limestone in the 26 MW unit absorbs sulfur from the coal, and can be replaced by other sorbents depending on types of coal available and stringency of local environmental regulations. Low temperature combustion reduces NOx formation and release of alkali salts and corrosion. The air heat is exhausted through a heat recovery boiler to produce process steam, then can be refed into the combustion chamber to satisfy preheat requirements. All parts of the cogenerator are designed to withstand full combustion temperature (1500 F) in the event of air flow stoppage. Costs are compared with those of a coal fired boiler and purchased power, and it is shown that the increased capital requirements for cogenerator apparatus will yield a 2.8 year payback. Detailed flow charts, diagrams and costs schedules are included.

2007 NASA Seal/Secondary Air System Workshop. Volume 1

Science.gov (United States)

Steinetz, Bruce M.; Hendricks, Robert C.; Delgado, Irebert

2008-01-01

The 2007 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA's new Orion project aimed at developing a new spacecraft that will fare astronauts to the International Space Station, the Moon, Mars, and beyond; (ii) Overview of NASA's fundamental aeronautics technology project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA's turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing seal leakage as well as high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Turbine seal development topics covered include a method for fast-acting HPT blade tip clearance control, noncontacting low-leakage seals, intershaft seals, and a review of engine seal performance requirements for current and future Army engine platforms.

Energy conservation with semi-controlled areas by air conditioning in nursery schools. The nursery school Dragvoll

Energy Technology Data Exchange (ETDEWEB)

Brattset, O; Hestnes, A G

1985-02-01

Dragvoll nursery school in Trondheim (Norway) is designed with a central winter garden built up by glazed walls and a glass roof, and surrounded by classrooms. The ventilating air is preheated in a heat exchanger, and then postheated in the said garden by the solar flux before entering the air conditioning system. A comparative evaluation of the energy consumption with the total floor area of about 57 m/sup 2/ is done in relation to a conventionally built nursery school with a floor area of about 520 m/sup 2/. The saving potential is found to 52%. 9 drawing.

arXiv Gravitational wave production from preheating -- parameter dependence

CERN Document Server

Figueroa, Daniel G.

2017-10-31

Parametric resonance is among the most efficient phenomena generating gravitational waves (GWs) in the early Universe. The dynamics of parametric resonance, and hence of the GWs, depend exclusively on the resonance parameter q. The latter is determined by the properties of each scenario: the initial amplitude and potential curvature of the oscillating field, and its coupling to other species. Previous works have only studied the GW production for fixed value(s) of q. We present an analytical derivation of the GW amplitude dependence on q, valid for any scenario, which we confront against numerical results. By running lattice simulations in an expanding grid, we study for a wide range of q values, the production of GWs in post-inflationary preheating scenarios driven by parametric resonance. We present simple fits for the final amplitude and position of the local maxima in the GW spectrum. Our parametrization allows to predict the location and amplitude of the GW background today, for an arbitrary q. The GW si...

Performance Evaluation of Photovoltaic Solar Air Conditioning

Directory of Open Access Journals (Sweden)

Snegirjovs A.

2016-12-01

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

Performance Evaluation of Photovoltaic Solar Air Conditioning

Science.gov (United States)

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

2016-12-01

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

New pre-heating system for natural gas pressure regulating stations

International Nuclear Information System (INIS)

Zullo, G.; Vertuani, C.; Borghesani, O.; Vignoli, F.

1999-01-01

Costs for running natural gas pressure regulating stations are mainly due to operation and maintenance of a natural gas preheating system, usually equipment with a hot water boiler or an armour-plated electric resistance immersed in a fluid. The article describe a system, considering a natural circulation boiler which uses steam/condensate (at 100 degrees C and 0,5 bar) as a thermal conductor, in thermodynamic balance and in absence of un condensable. This new boiler, already operating with satisfactory results in heating system for industrial buildings, does not require testing, notifications, periodical inspections by the competent authorities, constant monitoring by trained or patented staff. Besides, it allows easier installations procedures and running cost savings. The system, to be considered as static because it has no moving parts, is a good alternative to conventional forced hot water circulation or electric heating system [it

ESR studies of Bunsen-type methane-air flames. II. The effects of the addition of halogenated compounds to the secondary air on the hydrogen atoms in the flame

Energy Technology Data Exchange (ETDEWEB)

Noda, S; Fujimoto, S; Claesson, O; Yoshida, H

1983-09-01

Hydrogen atoms in a methane-air Bunsen-type flame were detected by the flame-in-cavity ESR method. The addition of a halogenated compound to the secondary air reduced the H-atom concentration linearly with an increase in additive concentration. These 8 halogenated compounds examined showed increased effectiveness in scavenging H atoms in this order: hydrochloric acid < dichlorodifluoromethane < chloroform < methyl chloride < methylene chloride < trichlorofluoromethane < carbon tetrachlorie < methyl bromide. The chemical effects of these additives on the combustion reactions agree well with the inhibitor indices for these compounds. 14 references, 3 figures.

The study on pre-heat conditions in the equivalent-dose estimation of holocene loess using the single-aliquot regenerative-dose (SAR) protocol

International Nuclear Information System (INIS)

Jia Yaofeng; Huang Chunchang; Pang Jiangli; Lu Xinwei; Zhang Xu

2008-01-01

The thermal treatment in the equivalent-dose estimation often is carried in the OSL dating, and pre-heat is a main thermal treatment. Due to which will originate the problems of thermal transfer and thermal activation, the thermal treatment and the setup of their conditions are key problems influencing the accuracy of OSL dating. The paper combined the temperature of pre-heat and cut-heat used in the routine measurement of IRSL and Post-IR OSL, and then estimated the equivalent-dose of several loess samples. The estimated result presents that the equivalent-dose depends on the heat temperature, especially depends on the cut-heat temperature, which is to say that the equivalent-dose increases with the cut-heat temperature; a plateau of equivalent-dose appears when using the 200-240 degree C cut-heat in the range of 200-300 degree C pre-heat, and the equivalent-doses estimated by IRSL and Post-IR OSL respectively are close to each other, which resulted from the similar sensitivity change direction of optical stimulated signals and its smaller change range in the measurement cycles using the combined temperature of pre- heat and cut-heat, and the incomplete calibration of sensitivity change of optical stimulated signals in the whole measurement cycles caused the variation of estimated equivalent-dose corresponding to the cut-heat temperature. (authors)

Numerical analysis of the efficiency of earth to air heat exchange systems in cold and hot-arid climates

International Nuclear Information System (INIS)

Fazlikhani, Faezeh; Goudarzi, Hossein; Solgi, Ebrahim

2017-01-01

Highlights: • A numerical model is developed to evaluate performance of earth to air heat exchanger. • The cooling/heating potential of earth to air heat exchanger is investigated in hot-dry and cold climates. • The more performance of earth to air heat exchanger in hot-dry climates compared to cold climates. • The high efficiency of earth to air heat exchanger for pre-heating in both hot-dry and cold climates. - Abstract: In order to examine and compare the efficiency of earth to air heat exchanger (EAHE) systems in hot-arid (Yazd) and cold (Hamadan) climates in Iran a steady state model was developed to evaluate the impact of various parameters including inlet air temperatures, pipe lengths and ground temperatures on the cooling and heating potential of EAHEs in both climates. The results demonstrated the ability of the system to not only improve the average temperature and decrease the temperature fluctuation of the outlet air temperature of EAHE, but also to trigger considerable energy saving. It was found that in both climates, the system is highly utilized for pre-heating, and its usage is unfeasible in certain periods throughout the year. In winter, EAHEs have the potential of increasing the air temperature in the range of 0.2–11.2 °C and 0.1–17.2 °C for Yazd and Hamadan, respectively. However, in summer, the system decreases the air temperature for the aforementioned cities in the range of 1.3–11.4 °C and 5.7–11.1 °C, respectively. The system ascertains to be more efficient in the hot-arid climate of Yazd, where it can be used on 294 days of the year, leading to 50.1–63.6% energy saving, when compared to the cold climate of Hamadan, where it can be used on 225 days of the year resulting in a reduction of energy consumption by 24.5–47.9%.

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

OpenAIRE

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

2010-01-01

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

Solar project description for homes by Marilynn multi-family residence, Albuquerque, New Mexico

Science.gov (United States)

Moore, D.

1981-03-01

The system is designed to provide solar energy for space heating and preheating DHW. Solar energy is collected by 18 liquid flat plate collectors with a gross area of 346 square feet. Solar energy is transferred from the collector array to a 1000 gallon storage tank. Freeze protection is provided by a 50% ethylene glycol and 50% water. Solar energy is delivered to a liquid-to-air heat exchanger in the space heating subsystem in order to preheat outside air for the heat pump. Preheated city water is stored in a 30 gallon preheat storage tank and supplied, on demand, to a conventional 40 gallon DHW tank.

A method to minimise the fading effects of LiF:Mg,Ti (TLD-600 and TLD-700) using a pre-heat technique.

Science.gov (United States)

Lee, YoungJu; Won, Yuho; Kang, Kidoo

2015-04-01

Passive integrating dosemeters [thermoluminescent dosimeter (TLD) and optically stimulated luminescence (OSL)] are the only legally permitted individual dosemeters for occupational external radiation exposure monitoring in Korea. Also its maximum issuing cycle does not exceed 3 months, and the Korean regulations require personal dosemeters for official assessment of external radiation exposure to be issued by an approved or rather an accredited dosimetry service according to ISO/IEC 17025. KHNP (Korea Hydro & Nuclear Power, LTD), a unique operating company of nuclear power plants (NPPs) in Korea, currently has a plan to extend a TLD issuing cycle from 1 to 3 months under the authors' fading error criteria, ±10%. The authors have performed a feasibility study that minimises post-irradiation fading effects within their maximum reading cycle employing pre-heating technique. They repeatedly performed irradiation/reading a bare TLD chip to determine optimum pre-heating conditions by analysing each glow curve. The optimum reading conditions within the maximum reading cycle of 3 months were decided: a pre-heating temperature of 165°C, a pre-heating time of 9 s, a heating rate of 25°C s(-1), a reading temperature of 300°C and an acquisition time of 10 s. The fading result of TLD-600 and TLD-700 carried by newly developed time temperature profile (TTP) showed a much smaller fading effect than that of current TTP. The result showed that the fading error due to a developed TTP resulted in a ∼5% signal loss, whereas a current TTP caused a ∼15% loss. The authors also carried out a legal performance test on newly developed TTP to confirm its possibility as an official dosemeter. The legal performance tests that applied the developed TTP satisfied the criteria for all the test categories. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-04-30

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

Heat pipes in modern heat exchangers

International Nuclear Information System (INIS)

Vasiliev, Leonard L.

2005-01-01

Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 10 3 -10 5 W/m 2 K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included

A new conceptual cold-end design of boilers for coal-fired power plants with waste heat recovery

International Nuclear Information System (INIS)

Yang, Yongping; Xu, Cheng; Xu, Gang; Han, Yu; Fang, Yaxiong; Zhang, Dongke

2015-01-01

Highlights: • A new cold-end design of boilers for CFPPs with waste heat recovery is proposed. • Thermodynamic and economic analyses are quantitatively conducted. • Higher energy efficiency improvement and greater economic benefits are achieved. • Lower exergy destruction and better matched energy level are obtained. - Abstract: After conducting an in-depth analysis of the conventional boiler cold-end design for waste heat recovery, this work proposed a new conceptual boiler cold-end design integrated with the steam cycle in a 1000 MW CFPP, in which the preheating of air was divided into high-temperature air preheater (HTAP), main air preheater (MAP) and low-temperature air preheater (LTAP). The HTAP and an economizer were installed in separate flue ducts, and the low temperature economizer (LTE) was situated between the MAP and the LTAP in the main flue duct to heat the condensed water. In the proposed boiler cold-end design, the flue gas waste heat was not only used to heat condensed water, but also to further preheat the combustion air. The air temperature at the air-preheater outlet increases and part of the steam bleeds with high exergy can be saved, resulting in greater energy-savings and better economics. Results showed that, for a typical 1000 MW CFPP in China, using the proposed boiler cold-end design for waste heat recovery could produce 13.3 MW e additional net power output with a heat rate reduction of approximately 112.0 kJ/kW h and could yield a net benefit of up to $85.8 M per year, which is much greater than those of the conventional cases. Exergy destruction is also reduced from 49.9 MW th in the conventional boiler cold-end design to 39.6 MW th in the proposed design

Gravitational wave production from preheating: parameter dependence

Energy Technology Data Exchange (ETDEWEB)

Figueroa, Daniel G. [Theory Division, CERN, 1211 Geneva (Switzerland); Torrentí, Francisco, E-mail: daniel.figueroa@cern.ch, E-mail: f.torrenti@csic.es [Instituto de Física Teórica IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain. (Spain)

2017-10-01

Parametric resonance is among the most efficient phenomena generating gravitational waves (GWs) in the early Universe. The dynamics of parametric resonance, and hence of the GWs, depend exclusively on the resonance parameter q . The latter is determined by the properties of each scenario: the initial amplitude and potential curvature of the oscillating field, and its coupling to other species. Previous works have only studied the GW production for fixed value(s) of q . We present an analytical derivation of the GW amplitude dependence on q , valid for any scenario, which we confront against numerical results. By running lattice simulations in an expanding grid, we study for a wide range of q values, the production of GWs in post-inflationary preheating scenarios driven by parametric resonance. We present simple fits for the final amplitude and position of the local maxima in the GW spectrum. Our parametrization allows to predict the location and amplitude of the GW background today, for an arbitrary q . The GW signal can be rather large, as h {sup 2Ω}{sub GW}( f {sub p} ) ∼< 10{sup −11}, but it is always peaked at high frequencies f {sub p} ∼> 10{sup 7} Hz. We also discuss the case of spectator-field scenarios, where the oscillatory field can be e.g. a curvaton, or the Standard Model Higgs.

LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

Science.gov (United States)

Ko, Suk M.

1980-01-01

This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

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

Science.gov (United States)

Heller, Lukas; Hoffmann, Jaap

2017-06-01

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

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.

An investigation into a laboratory scale bubble column humidification dehumidification desalination system powered by biomass energy

International Nuclear Information System (INIS)

Rajaseenivasan, T.; Srithar, K.

2017-01-01

Highlights: • A biomass based humidification dehumidification desalination system is tested. • System is analyzed with the direct and preheated air supply. • Highest distillate rate of 6.1 kg/h is collected with the preheated air supply. • The minimum fuel feed of 0.2 kg is needed to produce 1 kg of fresh water. - Abstract: This article describes a biomass powered bubble column humidification-dehumidification desalination system. This system mainly consists of a biomass stove, air heat exchanger, bubble column humidifier and dehumidifier. Saw dust briquettes are used as biomass fuel in the stove. First level of experiments are carried out in bubble column humidifier with ambient air supply to select the best water depth, bubble pipe hole diameter and water temperature. Experiments are conducted by integrating the humidifier with the dehumidifier. Air is sent to the humidifier with and without pre-heating. Preheating of air is carried out in the air heat exchanger by using the flue gas and flame from the combustion chamber. It is observed that the humidifier ability is augmented with the rise in water depth, water temperature, mass flow rate of air and cooling water flow rate, and reduction in bubble pipe hole diameter. It is found from Taguchi analysis that the water temperature dominates in controlling the humidifier performance compared to other parameters. Better specific humidity is recorded with a bubble pipe hole diameter of 1 mm, water depth of 170 mm and water temperature of 60 °C. Highest distillate of 6.1 kg/h and 3.5 kg/h is collected for the HDH desalination system with preheated air and direct air supply respectively. Recovery of waste heat using an air heat exchanger reduces the fuel consumption from 0.36 kg to 0.2 kg for producing 1 kg of distilled water. Lowest distilled water cost of 0.0133 US $/kg through preheated air supply and 0.0231 US $/kg through direct air supply is observed. A correlation is developed to estimate the mass transfer

Maximization

Directory of Open Access Journals (Sweden)

A. Garmroodi Asil

2017-09-01

To further reduce the sulfur dioxide emission of the entire refining process, two scenarios of acid gas or air preheats are investigated when either of them is used simultaneously with the third enrichment scheme. The maximum overall sulfur recovery efficiency and highest combustion chamber temperature is slightly higher for acid gas preheats but air preheat is more favorable because it is more benign. To the best of our knowledge, optimization of the entire GTU + enrichment section and SRU processes has not been addressed previously.

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)

Hamid, Mohammed O.A.; Zhang, Bo; Yang, Luopeng

2014-01-01

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

Numerical study of effect of wall parameters on catalytic combustion characteristics of CH4/air in a heat recirculation micro-combustor

International Nuclear Information System (INIS)

Yan, Yunfei; Wang, Haibo; Pan, Wenli; Zhang, Li; Li, Lixian; Yang, Zhongqing; Lin, Changhai

2016-01-01

Highlights: • Combustion in heat recuperation micro-combustors with different materials was studied. • Heat concentration is more obvious with thermal conductivity decreasing. • Combustor with copper baffles has uniform temperature distribution and best preheating effectiveness. • Influence of wall thermal conductivity is negligible on OH(s) coverage. • Methane conversion rate firstly increases and then decreases with h increasing. - Abstract: Premixed combustion of methane/air mixture in heat recuperation micro-combustors made of different materials (corundum, quartz glass, copper and ferrochrome) was investigated. The effects of wall parameters on the combustion characters of a CH 4 /air mixture under Rhodium catalyst as well as the influence of wall materials and convection heat transfer coefficients on the stable combustion limit, temperature field, and free radicals was explored using numerical analysis methodology. The results show that with a decrease of thermal conductivity of wall materials, the temperature of the reaction region increases and hot spots becomes more obvious. The combustor with copper baffles has uniform temperature distribution and best preheating effectiveness, but when inlet velocity is too small, the maximum temperature in the combustor with copper or ferrochrome baffles is well beyond the melting point of the materials. With an increase in thermal conductivity, the preheat zone for premixed gas increases, but the influence of thermal conductivity on OH(s) coverage is negligible. With an increase of the wall convection heat transfer coefficient, the methane conversion rate firstly increases, then decreases reaching a maximum value at h = 8.5 W/m 2 K, however, the average temperature of both the axis and exterior surface of the combustor decrease.

Connectable solar air collectors

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Bosanac, M.

2002-02-01

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

Image-guided percutaneous removal of ballistic foreign bodies secondary to air gun injuries.

Science.gov (United States)

Rothermund, Jacob L; Rabe, Andrew J; Zumberge, Nicholas A; Murakami, James W; Warren, Patrick S; Hogan, Mark J

2018-01-01

Ballistic injuries with retained foreign bodies from air guns is a relatively common problem, particularly in children and adolescents. If not removed in a timely fashion, the foreign bodies can result in complications, including pain and infection. Diagnostic methods to identify the presence of the foreign body run the entire gamut of radiology, particularly radiography, ultrasound (US) and computed tomography (CT). Removal of the foreign bodies can be performed by primary care, emergency, surgical, and radiologic clinicians, with or without imaging guidance. To evaluate the modalities of radiologic detection and the experience of image-guided ballistic foreign body removal related to air gun injuries within the interventional radiology department of a large pediatric hospital. A database of more than 1,000 foreign bodies that were removed with imaging guidance by the interventional radiologists at our institution was searched for ballistic foreign bodies from air guns. The location, dimensions, diagnostic modality, duration, complications and imaging modality used for removal were recorded. In addition, the use of sedation and anesthesia required for the procedures was also recorded. Sixty-one patients with ballistic foreign bodies were identified. All foreign bodies were metallic BBs or pellets. The age of the patients ranged from 5 to 20 years. The initial diagnostic modality to detect the foreign bodies was primarily radiography. The primary modality to assist in removal was US, closely followed by fluoroscopy. For the procedure, 32.7% of the patients required some level of sedation. Only two patients had an active infection at the time of the removal. The foreign bodies were primarily in the soft tissues; however, successful removal was also performed from intraosseous, intraglandular and intratendinous locations. All cases resulted in successful removal without complications. Image-guided removal of ballistic foreign bodies secondary to air guns is a very

Formation And Distribution of Brittle Structures in Friction Stir Welding of AA 6061 To Copper. Influence of Preheat

Directory of Open Access Journals (Sweden)

Seyed Vahid Safi

2016-06-01

Full Text Available In this paper, apart from introducing brand – new warm friction stir welding (WFSW method, the effect of preheating on friction stir welded of copper and aluminum alloys sheets and its influence on improving the mechanical properties of the weld were investigated. Sheets of aluminum alloy 6061 and copper with thickness of 5mm were used. The tool was made of tool steel of grade H13 with a threaded cone shape. Rotational speeds (w of 1200-1400 rpm and traverse speeds (v of 50-100 mm/min were used for better understanding the behavior of the tools during the heat input. The sheets were kept in furnace with temperature of 75 ˚C and 125˚C and welding was done afterwards. At last, tensile and micro hardness tests were done to compare the mechanical properties of the welds. Considering to the high thermal conductivity of both copper and aluminum, the reason of increase in strength of the joints could be related to the low temperature gradient between the weld zone and base metal because the heat gets out of the stir zone with lower steep. A significant increase in hardness is observed in the SZ for the following reasons: (i the presence of concentric grains with intensely refined recrystallization and (ii the presence of intermetallic compounds. The tensile test results showed 85% increase in the strength of preheated joints. The maximum strength occurs for preheating of 75˚C, rotational speed of 1200 rpm and traverse speed of 50 mm/min. In the present study, intermetallic compounds and the precipitates are moved to the grain boundaries during the welding process. These precipitates act as strong obstacles to the movements of dislocations and increase the deformation resistance of material. This phenomenon may result in locking of grain boundaries and consequently decrease of grain size. This grain refinement can improve the mechanical properties of welds. Accordingly, hardness and strength of the material will be increased.

Simplified Hybrid-Secondary Uncluttered Machine And Method

Science.gov (United States)

Hsu, John S [Oak Ridge, TN

2005-05-10

An electric machine (40, 40') has a stator (43) and a rotor (46) and a primary air gap (48) has secondary coils (47c, 47d) separated from the rotor (46) by a secondary air gap (49) so as to induce a slip current in the secondary coils (47c, 47d). The rotor (46, 76) has magnetic brushes (A, B, C, D) or wires (80) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments. A method of providing a slip energy controller is also disclosed.

MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

Science.gov (United States)

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

2014-05-01

Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority of our experiments showed smooth monotonic increases in MgO sound speed and shock temperature with pressure from 197 to 243 GPa. The measured temperatures as well as the slopes of the pressure dependences for both temperature and sound speed were in good agreement with those calculated numerically for the solid phase at our peak shock compression conditions. Most observed sound speeds, however, were ~800 m/s higher than those predicted by the model. A single unconfirmed data point at 239 GPa showed anomalously low temperature and sound speed, which could both be explained by partial melting in this experiment and could suggest that the Hugoniot of MgO preheated to 2300 K crosses its melting line just slightly above 240 GPa.

MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

International Nuclear Information System (INIS)

Fat'yanov, O V; Asimow, P D

2014-01-01

Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority of our experiments showed smooth monotonic increases in MgO sound speed and shock temperature with pressure from 197 to 243 GPa. The measured temperatures as well as the slopes of the pressure dependences for both temperature and sound speed were in good agreement with those calculated numerically for the solid phase at our peak shock compression conditions. Most observed sound speeds, however, were ∼800 m/s higher than those predicted by the model. A single unconfirmed data point at 239 GPa showed anomalously low temperature and sound speed, which could both be explained by partial melting in this experiment and could suggest that the Hugoniot of MgO preheated to 2300 K crosses its melting line just slightly above 240 GPa.

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

Energy Technology Data Exchange (ETDEWEB)

Cuperman, S. [School of Physics and Astronomy, Tel Aviv University, 69978 Tel-Aviv (Israel); Bruma, C. [School of Physics and Astronomy, Tel Aviv University, 69978 Tel-Aviv (Israel) and College of Judea and Samaria, 44837 Ariel (Israel)]. E-mail: edycb@post.tau.ac.il; Komoshvili, K. [School of Physics and Astronomy, Tel Aviv University, 69978 Tel-Aviv (Israel); College of Judea and Samaria, 44837 Ariel (Israel)

2007-03-05

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.

2005 NASA Seal/Secondary Air System Workshop, Volume 1

Science.gov (United States)

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

2006-01-01

The 2005 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA s new Exploration Initiative program aimed at exploring the Moon, Mars, and beyond; (ii) Overview of the NASA-sponsored Propulsion 21 Project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA s turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts including tip clearance control, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Several organizations presented development efforts aimed at developing faster clearance control systems and associated technology to meet future engine needs. The workshop also covered several programs NASA is funding to develop technologies for the Exploration Initiative and advanced reusable space vehicle technologies. NASA plans on developing an advanced docking and berthing system that would permit any vehicle to dock to any on-orbit station or vehicle. Seal technical challenges (including space environments, temperature variation, and seal-on-seal operation) as well as plans to develop the necessary "androgynous" seal technologies were reviewed. Researchers also reviewed tests completed for the shuttle main landing gear door seals.

Establishment of welding process without PWHT and preheating in SGV480 plate for nuclear reactor containment vessel

International Nuclear Information System (INIS)

Watanabe, Nozomu; Higashikubo, Tomohiro; Nagamura, Takafumi; Yoshimoto Kentaro

2000-01-01

Ordinances of Japan's Ministry of International Trade and Industry provide that welded joints more than 38 mm thick used in nuclear reactor containment vessels undergo Post Weld Heat Treatment (PWHT). PWHT is difficult to apply in the field, however. We made SGV480 plate tougher and more weldable by using a Thermo-Mechanical Control Process (TMCP) in rolling. Such plate can be used without PWHT or preheating up to 55 mm thick at lowest service temperature -19degC. (author)

Establishment of welding process without PWHT and preheating in SGV480 plate for nuclear reactor containment vessel

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Nozomu; Higashikubo, Tomohiro; Nagamura, Takafumi [Mitsubishi Heavy Industries. Ltd., Kobe Shipyard and Machinery Works (Japan); Yoshimoto Kentaro [Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan). Takasago Research and Development Center

2000-07-01

Ordinances of Japan's Ministry of International Trade and Industry provide that welded joints more than 38 mm thick used in nuclear reactor containment vessels undergo Post Weld Heat Treatment (PWHT). PWHT is difficult to apply in the field, however. We made SGV480 plate tougher and more weldable by using a Thermo-Mechanical Control Process (TMCP) in rolling. Such plate can be used without PWHT or preheating up to 55 mm thick at lowest service temperature -19degC. (author)

The development of air cooled condensation systems

International Nuclear Information System (INIS)

Bodas, J.

1990-01-01

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

Possible negative consequences of the secondary air contamination on the quality of accumulated drinking water

International Nuclear Information System (INIS)

Rihova Ambrozova, J.; Hubackova, J.; Cihakova, I.

2008-01-01

At the present time when requirements on quality of drinking water are increased, it is necessary not only to put stress on technological processes used in its preparation, but also there is a need to secure that water is distributed even to the consumer in that quality as it leaves a water station. Through a systematic surveillance of water-supply companies within the framework of biological audits it has been found out that the important points in a distribution network where the quality of water is deteriorated are the water reservoirs. Deterioration in quality of accumulated water is jointly caused by elements of technological, constructional and biological nature. The secondary air contamination has a substantial influence on the creation of bio-films on walls and the presence of microorganisms in accumulated drinking water. To this end, a water twin-compartment reservoir has been systematically evaluated during operation, cleaning meantime and before cleaning. The results of hydro-biological and microbiological analysis have confirmed the input of particles and microorganisms through air, their presence in surface level of accumulated water as well as scrapings from accumulation walls. The surveillance considered also the situation without a fixed filter unit, without door lining etc. On fixing a tested filter system into ventilation duct the risk of air contamination was lowered to minimum. (authors)

Preheat effect on titanium plate fabricated by sputter-free selective laser melting in vacuum

Science.gov (United States)

Sato, Yuji; Tsukamoto, Masahiro; Shobu, Takahisa; Yamashita, Yorihiro; Yamagata, Shuto; Nishi, Takaya; Higashino, Ritsuko; Ohkubo, Tomomasa; Nakano, Hitoshi; Abe, Nobuyuki

2018-04-01

The dynamics of titanium (Ti) melted by laser irradiation was investigated in a synchrotron radiation experiment. As an indicator of wettability, the contact angle between a selective laser melting (SLM) baseplate and the molten Ti was measured by synchrotron X-rays at 30 keV during laser irradiation. As the baseplate temperature increased, the contact angle decreased, down to 28° at a baseplate temperature of 500 °C. Based on this result, the influence of wettability of a Ti plate fabricated by SLM in a vacuum was investigated. It was revealed that the improvement of wettability by preheating suppressed sputtering generation, and a surface having a small surface roughness was fabricated by SLM in a vacuum.

Hoosier Magnetics

Energy Technology Data Exchange (ETDEWEB)

None, None

2015-09-30

Hoosier Magnetics proposes to replace the indirect clinker water cooling system with a cooling system that recycles heat from the hot ferrite to preheat the combustion air. This innovative process would significantly reduce the amount of natural gas required to heat the combustion air while eliminating Hoosier’s largest source of downtime. According to the Department of Energy’s Industrial Technologies Program for Energy Efficiency and Renewable Energy, process temperature is customarily used as a rough indication of where preheating air will be cost effective. Previous studies have concluded that processes operating above 1,600° F are ideal candidates for the utilization of pre-heated combustion air. Hoosier Magnetics’ operating temperatures run between 1800-2200° F making Hoosier the perfect candidate. Using preheated air at 1200° F will result in 35% fuel savings, or $298,935 annually. Additionally, the new system would have improved process reliability and result in both production efficiency increases and cost savings. This technology is NOT practiced or utilized on a wide-spread basis but could have a significant energy reduction impact in many different high heat utilizing industries in the country. While the energy savings is apparent with this theory the application and design of such a process has not been studied.

Experimental evaluation of sorbents for sulfur control in a coal-fueled gas turbine slagging combustor

International Nuclear Information System (INIS)

Cowell, L.H.; Wen, C.S.; LeCren, R.T.

1992-01-01

This paper reports on a slagging combustor that has been used to evaluate three calcium-based sorbents for sulfur capture efficiency in order to assess their applicability for use in a oil-fueled gas turbine. Testing is competed in a bench-scale combustor with one-tenth the heat input needed for the full-scale gas turbine. The bench-scale rig is a two-stage combustor featuring a fuel-rich primary zone an a fuel-lean secondary zone. The combustor is operated at 6.5 bars with inlet air preheated to 600 K. Gas temperatures of 1840 K are generated in the primary zone and 1280 K in the secondary zone. Sorbents are either fed into the secondary zone or mixed with the coal-water mixture and fed into the primary zone. Dry powered sorbents are fed into the secondary zone by an auger into one of six secondary air inlet ports. The three sorbents tested in the secondary zone include dolomite, pressure-hydrated dolomitic lime, and hydrated lime. Sorbents have been tested while burning coal-water mixtures with coal sulfur loadings of 0.56 to 3.13 weight percent sulfur. Sorbents are injected into the secondary zone at varying flow rates such that the calcium/sulfur ratio varies from 0.5 to 10.0

New Colloidal Lithographic Nanopatterns Fabricated by Combining Pre-Heating and Reactive Ion Etching

Directory of Open Access Journals (Sweden)

Cong Chunxiao

2009-01-01

Full Text Available Abstract We report a low-cost and simple method for fabrication of nonspherical colloidal lithographic nanopatterns with a long-range order by preheating and oxygen reactive ion etching of monolayer and double-layer polystyrene spheres. This strategy allows excellent control of size and morphology of the colloidal particles and expands the applications of the colloidal patterns as templates for preparing ordered functional nanostructure arrays. For the first time, various unique nanostructures with long-range order, including network structures with tunable neck length and width, hexagonal-shaped, and rectangular-shaped arrays as well as size tunable nanohole arrays, were fabricated by this route. Promising potentials of such unique periodic nanostructures in various fields, such as photonic crystals, catalysts, templates for deposition, and masks for etching, are naturally expected.

Solid state NMR studies for a new carbonization process with high temperature preheating

Science.gov (United States)

Saito, Koji; Hatakeyama, Moriaki; Komaki, Ikuo; Katoh, Kenji

2002-01-01

A new carbonization process with rapid preheating and coke discharging at medium temperature has been developed in Japan. The result of this process shows that even when no or slightly coking coal is by 50 wt% the coking property is improved and a coking coke with cold strength usable at blast furnace can be manufactured with the new carbonization process. The mechanism of the coking property improvement was examined by coal properties using mainly solid state NMR ( 1H CRAMPS and 13C SPE/MAS, CP/MAS) and NMR imaging (single point imaging, in-situ imaging). It has been clarified that the molecular structure of coal is relaxed by the rapid heating treatment and, in addition, there is a close relation between hydrogen bonding and relaxation of the molecular structure of coal.

Mathematical modelling of NO emissions from high-temperature air combustion with nitrous oxide mechanism

International Nuclear Information System (INIS)

Yang, Weihong; Blasiak, Wlodzimierz

2005-01-01

A study of the mathematical modelling of NO formation and emissions in a gas-fired regenerative furnace with high-preheated air was performed. The model of NO formation via N 2 O-intermediate mechanism was proposed because of the lower flame temperature in this case. The reaction rates of this new model were calculated basing on the eddy-dissipation-concept. This model accompanied with thermal-NO, prompt-NO and NO reburning models were used to predict NO emissions and formations. The sensitivity of the furnace temperature and the oxygen availability on NO generation rate has been investigated. The predicted results were compared with experimental values. The results show that NO emission formed by N 2 O-intermediate mechanism is of outstanding importance during the high-temperature air combustion (HiTAC) condition. Furthermore, it shows that NO models with N 2 O-route model can give more reasonable profile of NO formation. Additionally, increasing excess air ratio leads to increasing of NO emission in the regenerative furnace. (author)

The angular distributions of charged secondaries in electromagnetic and hadronic extensive air showers at 10, 100, 1000 and 10 000 TeV

International Nuclear Information System (INIS)

Trzupek, A.; Mikocki, S.; Gress, J.; Kochocki, J.; Poirier, J.

1991-01-01

The angular distributions of secondary electrons and muons in extensive air showers (EAS) initiated by 10, 100, 1000 and 10 000 TeV gamma rays and protons are obtained with the aid of a new, hybrid Monte Carlo simulation method. In this method, a three-dimensional program is constructed out of two existing software codes: SHOWERSIM and EGS4. This procedure allows for fast, yet precise, calculations down to low secondary particle energies. The dependence of the angular distributions for different threshold energies is presented for 1000 TeV primary gamma ray and proton energy. (author)

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

DEFF Research Database (Denmark)

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

Frequent discussions of double skin façade energy performance have started a dialogue about the methods, models and tools for simulation of double façade systems and reliability of their results. Their reliability will increase with empirical validation of the software. Detailed experimental work...... was carried out in a full scale test facility ‘The Cube’, in order to compile three sets of high quality experimental data for validation purposes. The data sets are available for preheating mode, external air curtain mode and transparent insulation mode. The objective of this article is to provide the reader......’. This covers such problem areas as measurements of naturally induced air flow, measurements of air temperature under direct solar radiation exposure, etc. Finally, in order to create a solid foundation for software validation, the uncertainty and limitations in the experimental results are discussed. In part...

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

International Nuclear Information System (INIS)

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

2013-01-01

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

77 FR 12482 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Lead Ambient Air Quality...

Science.gov (United States)

2012-03-01

... Promulgation of Air Quality Implementation Plans; Indiana; Lead Ambient Air Quality Standards AGENCY... incorporates the National Ambient Air Quality Standards (NAAQS) for Pb promulgated by EPA in 2008. DATES: This... FR 66964) and codified at 40 CFR 50.16, ``National primary and secondary ambient air quality...

The absorbed dose in air of photons generated from secondary cosmic rays at sea level at Nagoya, Japan

International Nuclear Information System (INIS)

Akhmad, Y.R.

1995-01-01

Investigations have been carried out to determine the absorbed dose in air of photons generated from secondary cosmic radiation at sea level at Nagoya, Japan. To isolate the contribution from cosmic photons, the pulse-height distributions due to μ particles and electrons were eliminated from the observed pulse-height distribution of a measurement with a 3'' diam. spherical NaI(Tl) detector. The pulse height due to μ particles and electrons was inferred from the coincidence technique using two types of scintillation detectors with different sensitivities to photons. To obtain the photon fluence rate for further dose calculation, the pulse-height distribution of cosmic photons was unfolded by the iterative method. The mean and its standard deviation of the absorbed dose in air and fluence rate due to cosmic photons calculated from a one year observation are 2.86±0.05 nGy.h -1 and 0.1342±0.0015 photons.cm -2 .s -1 , respectively. The absorbed dose in air from cosmic photons was 0.5% lower during autumn to winter and 0.6% higher during spring to summer than the mean taken over the year. (author)

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

Science.gov (United States)

Yang, B; Sekhar, S C; Melikov, A K

2010-08-01

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

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

Directory of Open Access Journals (Sweden)

Jorge S. Carlos

2013-01-01

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

MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

OpenAIRE

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

2014-01-01

Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority ...

Capturing energy from ventilation air methane a preliminary design for a new approach

International Nuclear Information System (INIS)

Cluff, D.L.; Kennedy, G.A.; Bennett, J.G.; Foster, P.J.

2015-01-01

Methane is a potent greenhouse gas (GHG), discharged to the atmosphere by coalmining, the natural gas industry and natural biological processes, second only to carbon dioxide; thus, any reduction in atmospheric methane would be globally beneficial. The capture or use of ventilation air methane (VAM) is challenging because it is a high volume low concentration methane source. This results in the routine discharge of methane into the atmosphere. A review of VAM mitigation technologies is provided and the main disadvantages of the existing technologies are discussed. In the proposed VamTurBurner © system, the heat from the combustion chamber is transferred to the preheating zone either by a heat exchanger or by redirecting the combustion products to mix with the ventilation air stream from a coalmine. Gas turbines (GT) are used to produce electricity with the exhaust gases directed to mix with the incoming ventilation airflow. The turbulence introduced by the GT exhaust assists with mixing of the incoming ventilation airflow and the return flow of combustion products from the combustion chamber. The combustion products are a source of heat, which increases the temperature of the incoming ventilation air to a value high enough for the methane to undergo flameless combustion upon encountering the igniters. The high temperature combustion products enter a multi-generation system. The multi-generation system is based on mature engineering technology such as heat exchangers and steam turbines. The residual heat provides additional heat based products such as industrial scale drying, chilling by an absorption chiller or simply hot water. The VamTurBurner © uses the energy from the GT, igniters and VAM to provide clean efficient energy while mitigating the atmospheric emissions of methane. The opportunity to collect carbon credits may improve the economics. Since the VAM is a free energy source, the output of the system is greater than the purchased energy. - Highlights: �

A national environmental/energy workforce assessment. Post-secondary education profile: air. Final report on phase 2

International Nuclear Information System (INIS)

1978-12-01

This study is one of 16 volumes aggregating data on representative environmental education offerings in the United States at post-secondary education institutions and in the private sector of the economy. Structured around on-site interviews, the study describes the institutions' education programs--their program structure, representative course offerings, faculty structure, and program requirements. In addition, the study provides information on the employment history of graduates. Designed as Phase II of a three-phase program, the study presents the information on schools with emphasis on air pollution. The study is an overview. It doesn't include all environmental programs in the United States, and it makes no attempt to evaluate the program offerings

Secondary maxima in ozone profiles

Directory of Open Access Journals (Sweden)

R. Lemoine

2004-01-01

Full Text Available Ozone profiles from balloon soundings as well as SAGEII ozone profiles were used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurrence and amplitude of ozone secondary maxima is connected to ozone variability and trend at Uccle and account for a large part of the total ozone and lower stratospheric ozone variability.

Exergoeconomic Evaluation of a Modern Ultra-Supercritical Power Plant

Directory of Open Access Journals (Sweden)

Lingnan Wu

2012-09-01

Full Text Available In this paper, the exergoeconomic analysis was conducted to an existing ultra-supercritical coal-fired power plant in China to understand the cost-formation process, to evaluate the economic performance of each component and to find possible solutions for more cost-effective designs. The total revenue requirement (TRR and the specific exergy costing (SPECO methods were applied for economic analysis and exergy costing, respectively. Quantitative balances of exergy and exergetic costs as well as necessary auxiliary equations for both individual component and the overall system were established. The results show that the exergoeconomic factors of the furnace and heat exchangers at low temperature levels, including air preheater and low-pressure feedwater preheaters, are rather small; while those of other components are relatively large. Moving more heat absorption into furnace to use the effective radiation heat transfer, increasing the air preheating temperature and adding more low pressure feedwater preheaters can be promising solutions for future design.

A Systematic Review of Innate Immunomodulatory Effects of Household Air Pollution Secondary to the Burning of Biomass Fuels.

Science.gov (United States)

Lee, Alison; Kinney, Patrick; Chillrud, Steve; Jack, Darby

2015-01-01

Household air pollution (HAP)-associated acute lower respiratory infections cause 455,000 deaths and a loss of 39.1 million disability-adjusted life years annually. The immunomodulatory mechanisms of HAP are poorly understood. The aim of this study was to conduct a systematic review of all studies examining the mechanisms underlying the relationship between HAP secondary to solid fuel exposure and acute lower respiratory tract infection to evaluate current available evidence, identify gaps in knowledge, and propose future research priorities. We conducted and report on studies in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In all, 133 articles were fully reviewed and main characteristics were detailed, namely study design and outcome, including in vivo versus in vitro and pollutants analyzed. Thirty-six studies were included in a nonexhaustive review of the innate immune system effects of ambient air pollution, traffic-related air pollution, or wood smoke exposure of developed country origin. Seventeen studies investigated the effects of HAP-associated solid fuel (biomass or coal smoke) exposure on airway inflammation and innate immune system function. Particulate matter may modulate the innate immune system and increase susceptibility to infection through a) alveolar macrophage-driven inflammation, recruitment of neutrophils, and disruption of barrier defenses; b) alterations in alveolar macrophage phagocytosis and intracellular killing; and c) increased susceptibility to infection via upregulation of receptors involved in pathogen invasion. HAP secondary to the burning of biomass fuels alters innate immunity, predisposing children to acute lower respiratory tract infections. Data from biomass exposure in developing countries are scarce. Further study is needed to define the inflammatory response, alterations in phagocytic function, and upregulation of receptors important in bacterial and viral

Exhaust gas heat recovery through secondary expansion cylinder and water injection in an internal combustion engine

Directory of Open Access Journals (Sweden)

Nassiri Toosi Ali

2017-01-01

Full Text Available To enhance thermal efficiency and increase performance of an internal combustion engine, a novel concept of coupling a conventional engine with a secondary 4-stroke cylinder and direct water injection process is proposed. The burned gases after working in a traditional 4-stroke combustion cylinder are transferred to a secondary cylinder and expanded even more. After re-compression of the exhaust gases, pre-heated water is injected at top dead center. The evaporation of injected water not only recovers heat from exhaust gases, but also increases the mass of working gas inside the cylinder, therefore improves the overall thermal efficiency. A 0-D/1-D model is used to numerically simulate the idea. The simulations outputs showed that the bottoming cycle will be more efficient at higher engines speeds, specifically in a supercharged/turbocharged engine, which have higher exhaust gas pressure that can reproduce more positive work. In the modeled supercharged engine, results showed that brake thermal efficiency can be improved by about 17%, and brake power by about 17.4%.

Numerical analysis of temperature and flow effects in a dry, two-dimensional, porous-media reservoir used for compressed air energy storage

Energy Technology Data Exchange (ETDEWEB)

Wiles, L.E.

1979-10-01

The purpose of the work is to define the hydrodynamic and thermodynamic response of a CAES dry porous media reservoir subjected to simulated air mass cycling. The knowledge gained will provide, or will assist in providing, design guidelines for the efficient and stable operation of the air storage reservoir. The analysis and results obtained by two-dimensional modeling of dry reservoirs are presented. While the fluid/thermal response of the underground system is dependent on many parameters, the two-dimensional model was applied only to those parameters that entered the analysis by virtue of inclusion of the vertical dimension. In particular, the parameters or responses that were quantified or characterized include wellbore heat transfer, heat losses to the vertical boundaries of the porous zone, gravitationally induced flows, producing length of the wellbore, and the effects of nonuniform permeability. The analysis of the wellbore heat transfer included consideration of insulation, preheating (bubble development with heated air), and air mass flow rate.

Development and Application of an Oxidation Flow Reactor to Study Secondary Organic Aerosol Formation from Ambient Air

Science.gov (United States)

Palm, Brett Brian

Secondary organic aerosols (SOA) in the atmosphere play an important role in air quality, human health, and climate. However, the sources, formation pathways, and fate of SOA are poorly constrained. In this dissertation, I present development and application of the oxidation flow reactor (OFR) technique for studying SOA formation from OH, O3, and NO3 oxidation of ambient air. With a several-minute residence time and a portable design with no inlet, OFRs are particularly well-suited for this purpose. I first introduce the OFR concept, and discuss several advances I have made in performing and interpreting OFR experiments. This includes estimating oxidant exposures, modeling the fate of low-volatility gases in the OFR (wall loss, condensation, and oxidation), and comparing SOA yields of single precursors in the OFR with yields measured in environmental chambers. When these experimental details are carefully considered, SOA formation in an OFR can be more reliably compared with ambient SOA formation processes. I then present an overview of what OFR measurements have taught us about SOA formation in the atmosphere. I provide a comparison of SOA formation from OH, O3, and NO3 oxidation of ambient air in a wide variety of environments, from rural forests to urban air. In a rural forest, the SOA formation correlated with biogenic precursors (e.g., monoterpenes). In urban air, it correlated instead with reactive anthropogenic tracers (e.g., trimethylbenzene). In mixed-source regions, the SOA formation did not correlate well with any single precursor, but could be predicted by multilinear regression from several precursors. Despite these correlations, the concentrations of speciated ambient VOCs could only explain approximately 10-50% of the total SOA formed from OH oxidation. In contrast, ambient VOCs could explain all of the SOA formation observed from O3 and NO3 oxidation. Evidence suggests that lower-volatility gases (semivolatile and intermediate-volatility organic

Air pollution control technologies and their interactions

Energy Technology Data Exchange (ETDEWEB)

Nalbandian, H. [IEA Clean Coal Centre, London (United Kingdom)

2004-11-01

A large number of coal-fired power stations have been fitted/retrofitted with dedicated air pollutant control technologies. Experience shows that these technologies can have complex interactions and can impact each other as well as balance of plant, positively and/or negatively. Particulate matter (PM) is usually captured with electrostatic precipitators (ESPs) and fabric filters (FF). These technologies are efficient and reliable but their performance may be affected by modifying operating conditions and introducing primary measures for NOx reduction. Flue gas desulphurisation (FGD) systems for SO{sub 2} control have been installed in many facilities with the most popular technology being the wet limestone/gypsum scrubber. FGD use can decrease particulate matter and mercury emissions which is a major issue in the USA, cause an increase in carbon dioxide emissions, and in solids by-product. Primary measures such as low NOx burners (LNBs) and overfire air (OFA) minimise NOx formation but can increase carbon in ash (CIA) which can cause problems with fly ash sales but may also improve mercury capture. Reducing NOx emissions with selective catalytic reduction (SCR) can result in a decrease in particulate matter, an increase in SO{sub 3} emissions and trace increase in NH{sub 3}. This can cause fouling and loss of performance of the air preheater, due to the formation of ammonium sulphates. One way of alleviating this is improved soot-blowing and other cleaning capabilities. This report studies these and other interactions between existing air pollution control technologies in pulverised coal fired power plants. 249 refs., 13 figs., 18 tabs.

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

International Nuclear Information System (INIS)

Bari, S.; Lim, T.H.; Yu, C.W.

2002-01-01

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

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

Science.gov (United States)

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

2014-01-01

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

Modeling of crude oil fouling in preheat exchangers of refinery distillation units

Energy Technology Data Exchange (ETDEWEB)

Jafari Nasr, Mohammad Reza; Majidi Givi, Mehdi [National Petrochemical Research and Technology Company (NPC-RT), P.O. Box 14385, Tehran (Iran)

2006-10-15

The aim of this paper is to propose a new model for crude oil fouling in preheat exchangers of crude distillation units. The experimental results of Australian light crude oil with the tube side surface temperature between 200 and 260{sup o}C and fluid velocity ranged 0.25-0.4m/s were used [Z. Saleh, R. Sheikholeslami, A.P. Watkinson, Heat exchanger fouling by a light australian crude oil, in: Heat Exchanger Fouling and Cleaning Fundamentals and Applications, Santa Fe, 2003]. The amount of activation energy depends on the surface temperature has been calculated. A new model including a term for fouling formation and a term for fouling removal due to chemical and tube wall shear stress was proposed, respectively. The main superiority of the model are independent to Pr number, thermal fouling removal and determination of {beta} based on experimental tests. Finally using the proposed model the fouling rate of Australian light crude oil has been calculated and the threshold curves to identify fouling and no fouling formation zones have been drawn. (author)

Steam generator for nuclear reactors

International Nuclear Information System (INIS)

Byerley, W.M.; Bennett, R.R.

1978-01-01

In the steam generator, the primary medium is led through a U-shaped tube bundle heating up a secondary medium (feedwater) which flows around the tube bundle via a preheating chamber. In order to optimize heat transfer inside the preheating chamber, the feedwater is separated into a counterflow and a parallel flow with regard to the primary medium by means of partitioning walls and deflectors. The ratio is 70/30%. This way, boiling in the preheater is avoided, i.e. the high LMTD (logaritmic mean temperature difference) is fully utilized. (DG) [de

Modelling spontaneous ignition of wood, char and RDF in a lab-scale packed bed

NARCIS (Netherlands)

Blijderveen, M.; Bramer, Eduard A.; Brem, Gerrit

2013-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140 °C. In previous experiments it is found that at temperatures around 200 °C, in some circumstances, self- or spontaneous ignition can be achieved.

Modelling spontaneous ignition of wood, char and RDF in a lab-scale packed bed

NARCIS (Netherlands)

Blijderveen, M. van; Bramer, E.A.; Brem, G.

2013-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140°C. In previous experiments it is found that at temperatures around 200°C, in some circumstances, self- or spontaneous ignition can be achieved.

Spontaneous ignition of wood, char and RDF in a lab scale packed bed

NARCIS (Netherlands)

Blijderveen, M.; Gucho, Eyerusalem Merin; Gucho, Eyerusalem M.; Bramer, Eduard A.; Brem, Gerrit

2010-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140 °C. In previous experiments it is found that at temperatures around 200 °C, in some circumstances, self- or spontaneous ignition can be achieved.

AMBIENT CONDITIONS EFFECTS ON PERFORMANCE OF GAS TURBINE COGENERATION POWER PLANTS

OpenAIRE

Necmi Ozdemir*

2016-01-01

In this study, the performances of a simple and an air preheated cogeneration cycles in ambient conditions are compared with each other. A computer program written by the author in FORTRAN codes is used for the calculation of the enthalpy and entropy values of the streams, Exergy analysis is done and compared for the simple and the air preheated cogeneration cycles for different ambient conditions. The two cogeneration cycles are evaluated in terms of heat powers and electric, electrical to h...

Operation of neat pine oil biofuel in a diesel engine by providing ignition assistance

International Nuclear Information System (INIS)

Vallinayagam, R.; Vedharaj, S.; Yang, W.M.; Lee, P.S.

2014-01-01

Highlights: • Operational feasibility of neat pine oil biofuel has been examined. • Pine oil suffers lower cetane number, which mandates for necessary ignition assistance. • Ignition support is provided by preheating the inlet air and incorporating a glow plug. • At an inlet air temperature of 60 °C, the BTE for pine oil was found to be in par with diesel. • CO and smoke emissions were reduced by 13.2% and 16.8%, respectively, for neat pine oil. - Abstract: The notion to provide ignition support for the effective operation of lower cetane fuels in a diesel engine has been ably adopted in the present study for the sole fuel operation of pine oil biofuel. Having noted that the lower cetane number and higher self-ignition temperature of pine oil biofuel would inhibit its direct use in a diesel engine, combined ignition support in the form of preheating the inlet air and installing a glow plug in the cylinder head has been provided to improve the auto-ignition of pine oil. While, an air preheater, installed in the inlet manifold of the engine, preheated the inlet air so as to provide ignition assistance partially, the incorporation of glow plug in the cylinder head imparted the further required ignition support appropriately. Subsequently, the operational feasibility of neat pine oil biofuel has been examined in a single cylinder diesel engine and the engine test results were analyzed. From the experimental investigation, though the engine performance and emissions such as CO (carbon monoxide) and smoke were noted to be better for pine oil with an inlet air temperature of 40 °C, the engine suffered the setback of knocking due to delayed SOC (start of combustion). However, with the ignition support through glow plug and preheating of inlet air, the engine knocking was prevented and the normal operation of the engine was ensured. Categorically, at an inlet air temperature of 60 °C, BTE (brake thermal efficiency) was found to be in par with diesel, while

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Science.gov (United States)

Palm, Brett B.; de Sá, Suzane S.; Day, Douglas A.; Campuzano-Jost, Pedro; Hu, Weiwei; Seco, Roger; Sjostedt, Steven J.; Park, Jeong-Hoo; Guenther, Alex B.; Kim, Saewung; Brito, Joel; Wurm, Florian; Artaxo, Paulo; Thalman, Ryan; Wang, Jian; Yee, Lindsay D.; Wernis, Rebecca; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Liu, Yingjun; Springston, Stephen R.; Souza, Rodrigo; Newburn, Matt K.; Lizabeth Alexander, M.; Martin, Scot T.; Jimenez, Jose L.

2018-01-01

Secondary organic aerosol (SOA) formation from ambient air was studied using an oxidation flow reactor (OFR) coupled to an aerosol mass spectrometer (AMS) during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O3, over ranges from hours to days (O3) or weeks (OH) of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 µg m-3, depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA) after OH oxidation showed formation of typical oxidized OA factors and a loss of primary OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C ˜ 1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O3, they could only explain 10-50 % of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C = C bonds) are present in ambient air and can explain such additional SOA formation. To investigate the sources of the unmeasured SOA-forming gases during this campaign

Preliminary engineering design and cost of Advanced Compressed-Air Storage (ACAS) A-5 hybrid

Science.gov (United States)

Sosnowicz, E. J.; Blackman, J.; Woodhull, A. S.; Zaugg, P.

1981-08-01

The advanced compressed air energy (ACAS) plant investiated operates on a partial adiabatic, partial fuel fired cycle. Only a limited advancement in state-of-the-art technology is projected for this hybrid arrangement. The A-5 hybrid systems stores the heat of compression from the low pressure and intermediate pressure compressors in a thermal energy store (TES). The heat collected in the TES is available for preheating the air from the storage cavern prior to its entering the low pressure turbine combustor. This reduces the amount of fuel consumed during power generation. The fuel heat rate for the hybrid cycle is 2660 Btu/kWh as compared to approximately 4000 Btu/kWh for a conventional CAES plant. A virtual stand-off between the hybrid plant and a conventional CAES plant at 235 mills/kWh in 1990 dollars is shown. With a lower cost and increased fuel cost projections, the hybrid system operating cost is less than that for a conventional CAES plant.

The use of helical heat exchanger for heat recovery domestic water-cooled air-conditioners

International Nuclear Information System (INIS)

Yi Xiaowen; Lee, W.L.

2009-01-01

An experimental study on the performance of a domestic water-cooled air-conditioner (WAC) using tube-in-tube helical heat exchanger for preheating of domestic hot water was carried out. The main aims are to identify the comprehensive energy performance (space cooling and hot water preheating) of the WAC and the optimum design of the helical heat exchanger taking into account the variation in tap water flow rate. A split-type WAC was set up for experimental study at different indoor and outdoor conditions. The cooling output, the amount of recovered heat, and the power consumption for different hot water flow rates were measured. The experimental results showed that the cooling coefficient of performance (COP) of the WAC improves with the inclusion of the heat recovery option by a minimum of 12.3%. This can be further improved to 20.6% by an increase in tap water flow rate. Same result was observed for the comprehensive COP of the WAC. The maximum achievable comprehensive COP was 4.92 when the tap water flow rate was set at 7.7 L/min. The overall heat transfer coefficient of the helical heat exchanger under various operating conditions were determined by Wilson plot. A mathematical model relating the over all heat transfer coefficient to the outer pipe diameter was established which provides a convenient way of optimising the design of the helical heat exchanger

Solar project description for Public Service Company of New Mexico (lot 7) single family residence, Rio Rancho, New Mexico

Science.gov (United States)

1981-08-01

A solar space heating/domestic hot water system employing 150 square feet air flat plate collectors and 20,000 pounds of rock for storage is described. The collector, storage, energy to load, and auxiliary heat subsystems and five modes of operation are described. Auxiliary space heating is provided by an electric strip heater in the air ducts. The hot water system consists of an 80 gallon solar preheating tank which supplies a 40 gallon conventional tank. An electric heating element provides auxiliary heating in the preheat tank.

Air quality in barns for milk-fed calves

International Nuclear Information System (INIS)

Lavoie, J.

2007-01-01

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 (NH 3 ) which is toxic, colourless and flammable; hydrogen sulfide (H 2 S) which is very toxic, flammable; carbon dioxide (CO 2 ) which is colourless and odourless; nitrous oxide (N 2 O) which is colourless and flammable, but harmless to health in the short-term; carbon monoxide (CO) which is colourless, odourless and flammable; and methane (CH 4 ) 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

30 CFR 250.302 - Definitions concerning air quality.

Science.gov (United States)

2010-07-01

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

Modeling of a New Structure of Precision Air Conditioning System Using Secondary Condenser for Rh Regulation

Directory of Open Access Journals (Sweden)

Aries Subiantoro

2012-05-01

Full Text Available A dynamic mathematical model for a new structure of precision air conditioning (PAC has been developed. The proposed PAC uses an additional secondary condenser for relative humidity regulation compared to a basic refrigeration system. The work mechanism for this system and a vapour-compression cycle process of the system are illustrated using psychrometric chart and pressure-enthalpy diagram. A non-linear system model is derived based on the conservation of mass and energy balance principles and then linearized at steady state operating point for developing a 8th-order state space model suited for multivariable controller design. The quality of linearized model is analyzed in terms of transient response, controllability, observability, and interaction between input-output variables. The developed model is verified through simulation showing its ability for imitating the nonlinear behavior and the interaction of input-output variables.

Process to dry and preheat fine-grained bituminous coal using non- or weakly baking coal and/or carbon materials. Verfahren zur Trocknung und Vorerhitzung von feinkoerniger Steinkohle unter Verwendung nicht oder nur schwach backender Kohle und/oder Kohlenstofftraegern

Energy Technology Data Exchange (ETDEWEB)

Echterhoff, J.; Frick, H.; Schaper, A.; Mohmeyer, H.

1982-11-04

Fine-grained bituminous coal is dried and preheated in an inert gas to prevent its oxidation. The inert gas consists essentially of steam which originates from the coal to be dried. The coal is heated besides by using steam intensively but gently. The drying is carried out in a drying drum in co-current flow. The coal is mixed with a binding agent in the presence of steam. The dried and preheated coal is taken out and, after being covered with a binding agent, transported without further safety measures to the atmosphere, stored and further processed. (KHH).

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Directory of Open Access Journals (Sweden)

B. B. Palm

2018-01-01

Full Text Available Secondary organic aerosol (SOA formation from ambient air was studied using an oxidation flow reactor (OFR coupled to an aerosol mass spectrometer (AMS during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5 field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O3, over ranges from hours to days (O3 or weeks (OH of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 µg m−3, depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA after OH oxidation showed formation of typical oxidized OA factors and a loss of primary OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C ∼ 1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O3, they could only explain 10–50 % of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C = C bonds are present in ambient air and can explain such additional SOA formation. To investigate the sources of the

Mechanistic modelling of a cathode-supported tubular solid oxide fuel cell

Science.gov (United States)

Suwanwarangkul, R.; Croiset, E.; Pritzker, M. D.; Fowler, M. W.; Douglas, P. L.; Entchev, E.

A two-dimensional mechanistic model of a tubular solid oxide fuel cell (SOFC) considering momentum, energy, mass and charge transport is developed. The model geometry of a single cell comprises an air-preheating tube, air channel, fuel channel, anode, cathode and electrolyte layers. The heat radiation between cell and air-preheating tube is also incorporated into the model. This allows the model to predict heat transfer between the cell and air-preheating tube accurately. The model is validated and shows good agreement with literature data. It is anticipated that this model can be used to help develop efficient fuel cell designs and set operating variables under practical conditions. The transport phenomena inside the cell, including gas flow behaviour, temperature, overpotential, current density and species concentration, are analysed and discussed in detail. Fuel and air velocities are found to vary along flow passages depending on the local temperature and species concentrations. This model demonstrates the importance of incorporating heat radiation into a tubular SOFC model. Furthermore, the model shows that the overall cell performance is limited by O 2 diffusion through the thick porous cathode and points to the development of new cathode materials and designs being important avenues to enhance cell performance.

Study on lithium/air secondary batteries - Stability of NASICON-type lithium ion conducting glass-ceramics with water

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Satoshi; Imanishi, Nobuyuki; Zhang, Tao; Xie, Jian; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

2009-04-01

The water stability of the fast lithium ion conducting glass-ceramic electrolyte, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATP), has been examined in distilled water, and aqueous solutions of LiNO{sub 3}, LiCl, LiOH, and HCl. This glass-ceramics are stable in aqueous LiNO{sub 3} and aqueous LiCl, and unstable in aqueous 0.1 M HCl and 1 M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li-Al/Li{sub 3-x}PO{sub 4-y}N{sub y}/LATP/aqueous 1 M LiCl/Pt cell, where lithium phosphors oxynitrides Li{sub 3-x}PO{sub 4-y}N{sub y} (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64 V at 25 C, and no cell resistance change for 1 week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The water-stable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water. (author)

Specific aspects of turbulent flow in rectangular ducts

Directory of Open Access Journals (Sweden)

Stanković Branislav D.

2017-01-01

Full Text Available The essential ideas of investigations of turbulent flow in a straight rectangular duct are chronologically presented. Fundamentally significant experimental and theoretical studies for mathematical modeling and numerical computations of this flow configuration are analyzed. An important physical aspect of this type of flow is presence of secondary motion in the plane perpendicular to the streamwise direction, which is of interest from both the engineering and the scientific viewpoints. The key facts for a task of turbulence modeling and optimal choice of the turbulence model are obtained through careful examination of physical mechanisms that generate secondary flows. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no.TR-33018: Increase in Energy and Ecology Efficiency of Processes in Pulverized Coal-Fired Furnace and Optimization of Utility Steam Boiler Air Pre-heater by Using In-House Developed Software Tools

Modern State and Efficiency Analysis of Heat Recovery in Fuel Furnaces Using High Temperature Recuperators. Part 2

Directory of Open Access Journals (Sweden)

B. S. Soroka

2013-01-01

Full Text Available The paper analyzes various factors that affect upon heat transfer in high temperature recuperators, namely: heat transfer enhancement, heat exchange surface increase and rise of temperature head between primary and secondary heat transfer fluids. Comparison of experimental data with the results of mathematical and computational fluid dynamics (CFD modeling has been performed in the paper. The paper considers some new designs of high temperature heat recovery plants: tube recuperator equipped with internal inserts – secondary emitters inside tubes for metallurgical furnaces and high-efficient two-way radiative recuperators for machinery engineering furnaces.  Advantages of new recuperators in comparison with existing analogues have been estimated in the paper. These advantages are:  provision of additional fuel saving due to increase of preheating temperature of the combustion air and improvement of design stability by decrease of tube wall temperature.

Design and simulation of a hybrid ventilation system with earth-air heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Athienitis, A.K.; Zhao, M. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Roy, M. [Martin Roy and Associes Group Conseil Inc., Montreal, PQ (Canada)

2005-07-01

A simulation study was conducted during the design phase of a new circus building in Montreal which includes a hybrid ventilation system through which fresh air is supplied from an earth-air heat exchanger (EAHE). The EAHE has the potential to satisfy the cooling needs of the building and can also be used to preheat fresh air, thereby satisfying one-third or more of the building's heating needs. Another feature of the building is that it uses displacement ventilation by which the air is supplied at low velocities through large diffusers behind the top level seats or under the seats. In this study, computational fluid dynamics (CFD) simulations were carried out to help size the supply and return units of the heating, ventilating and air conditioning (HVAC) system, as well as the exhaust chimney. The primary objective of the CFD simulation was to determine the maximum velocity and temperature in the seated area to ensure thermal comfort. CFD simulation predictions were found to be in good agreement with preliminary measurements taken in the building. In order to monitor the operation of the system over the next year, the underground ducts were equipped with temperature sensors at several depths into the soil. The energy efficiency of the hybrid HVAC system will be assessed and the velocity and temperature distribution in the theatre will be examined under various operating and energy load conditions. 8 refs., 6 figs.

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.

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.

Air Quality Monitoring: Risk-Based Choices

Science.gov (United States)

James, John T.

2009-01-01

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

Characterization of air freshener emission: the potential health effects.

Science.gov (United States)

Kim, Sanghwa; Hong, Seong-Ho; Bong, Choon-Keun; Cho, Myung-Haing

2015-01-01

Air freshener could be one of the multiple sources that release volatile organic compounds (VOCs) into the indoor environment. The use of these products may be associated with an increase in the measured level of terpene, such as xylene and other volatile air freshener components, including aldehydes, and esters. Air freshener is usually used indoors, and thus some compounds emitted from air freshener may have potentially harmful health impacts, including sensory irritation, respiratory symptoms, and dysfunction of the lungs. The constituents of air fresheners can react with ozone to produce secondary pollutants such as formaldehyde, secondary organic aerosol (SOA), oxidative product, and ultrafine particles. These pollutants then adversely affect human health, in many ways such as damage to the central nervous system, alteration of hormone levels, etc. In particular, the ultrafine particles may induce severe adverse effects on diverse organs, including the pulmonary and cardiovascular systems. Although the indoor use of air freshener is increasing, deleterious effects do not manifest for many years, making it difficult to identify air freshener-associated symptoms. In addition, risk assessment recognizes the association between air fresheners and adverse health effects, but the distinct causal relationship remains unclear. In this review, the emitted components of air freshener, including benzene, phthalate, and limonene, were described. Moreover, we focused on the health effects of these chemicals and secondary pollutants formed by the reaction with ozone. In conclusion, scientific guidelines on emission and exposure as well as risk characterization of air freshener need to be established.

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

Science.gov (United States)

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

2017-03-01

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

Sequestration of Soil Carbon as Secondary Carbonates (Invited)

Science.gov (United States)

Lal, R.

2013-12-01

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

Combustion analysis of preheated crude sunflower oil in an IDI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Canakci, Mustafa; Ozsezen, Ahmet Necati; Turkcan, Ali [Department of Mechanical Education, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey)

2009-05-15

In this study, preheated crude sunflower oil (PCSO) was tested for combustion and emission properties against petroleum based diesel fuel (PBDF) in a naturally aspirated, indirect injection (IDI) engine. The cylinder gas pressure and heat release curves for PCSO at 75 C were similar to those of PBDF. The ignition delays for the PCSO were longer and the start of injection timing was earlier than for PBDF. The difference in the average brake torque was a decrease of 1.36% for PCSO though this was statistically insignificant. The brake specific fuel consumption increased by almost 5% more or less in proportion to the difference in calorific value, so that the 1.06% increase in thermal efficiency was again statistically insignificant. The emission test results showed that the decreases in CO{sub 2} emissions and smoke opacity 2.05% and 4.66%, respectively; however, this was not statistically significant, though in line with the apparent increase in thermal efficiency. There was a significant 34% improvement in the emissions of unburnt hydrocarbons. Carbon monoxide increased by 1.77% again the result was not statistically significant given the small number of repeat tests. The use of PCSO does not have any negative effects on the engine performance and emissions in short duration engine testing. (author)

Synthesis and physical properties of zinc-oxide textured films by using a filtered preheated hydrothermal

International Nuclear Information System (INIS)

Qiu, Jijun; Shin, Dongmyeong; He, Weizhen; Kim, Hyungkook; Hwang, Yoonhwae; Li, Xiaomin; Gao, Xiangdong

2014-01-01

Axially (c-axis)-oriented ZnO thick films with a ∼8.1 μm thickness were fabricated on ZnO seed layer coated substrates by using a filtered preheated hydrothermal solution. The thick films composed of single-crystal ZnO microrods with various diameters were formed by coalescing each nanorod together along their side surfaces. From the X-ray diffraction result a biaxial stress exists was found to exist in the as-grown thick films, and the stress gradually increased with increasing annealing temperatures from 200 to 550 .deg. C due to a degradation in the crystalline quality. The biaxial stress is responsible for the red-shift of the optical band gap of the ZnO thick films. Photoluminescence and Hall results revealed that the optical and the electrical properties of the thick films were degenerated after high-temperature annealing (> 200 .deg. C), which was due to the introduction of point defects, such as oxygen interstitials and zinc vacancies.

Synthesis and physical properties of zinc-oxide textured films by using a filtered preheated hydrothermal

Energy Technology Data Exchange (ETDEWEB)

Qiu, Jijun [Pusan National University, Busan (Korea, Republic of); Shin, Dongmyeong; He, Weizhen; Kim, Hyungkook; Hwang, Yoonhwae [Pusan National University, Miryang (Korea, Republic of); Li, Xiaomin; Gao, Xiangdong [Chinese Academy of Sciences, Shanghai (China)

2014-11-15

Axially (c-axis)-oriented ZnO thick films with a ∼8.1 μm thickness were fabricated on ZnO seed layer coated substrates by using a filtered preheated hydrothermal solution. The thick films composed of single-crystal ZnO microrods with various diameters were formed by coalescing each nanorod together along their side surfaces. From the X-ray diffraction result a biaxial stress exists was found to exist in the as-grown thick films, and the stress gradually increased with increasing annealing temperatures from 200 to 550 .deg. C due to a degradation in the crystalline quality. The biaxial stress is responsible for the red-shift of the optical band gap of the ZnO thick films. Photoluminescence and Hall results revealed that the optical and the electrical properties of the thick films were degenerated after high-temperature annealing (> 200 .deg. C), which was due to the introduction of point defects, such as oxygen interstitials and zinc vacancies.

Determination of average conversion coefficients between kerma in air and H⁎(10) using primary and secondary X-ray beams and transmitted in the diagnostic radiology energy range

International Nuclear Information System (INIS)

Santos, Josilene C.; Gonzalez, Alejandro H.L.; Costa, Paulo R.

2016-01-01

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

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

OpenAIRE

Cappa, Christopher D.; Jathar, Shantanu H.; Kleeman, Michael J.; Docherty, Kenneth S.; Jimenez, Jose L.; Seinfeld, John H.; Wexler, Anthony S.

2016-01-01

The influence of losses of organic vapors to chamber walls during secondary organic aerosol (SOA) formation experiments has recently been established. Here, the influence of such losses on simulated ambient SOA concentrations and properties is assessed in the UCD/CIT regional air quality model using the statistical oxidation model (SOM) for SOA. The SOM was fit to laboratory chamber data both with and without accounting for vapor wall losses following the approa...

Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire; Influencia del precalentamiento en las propiedades de uniones soldadas de acero API 5L-X80 soldadas con alambre tubular autoprotegido

Energy Technology Data Exchange (ETDEWEB)

Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

2004-07-01

The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs.

Ceramic applications in the advanced Stirling automotive engine

Science.gov (United States)

Tomazic, W. A.; Cairelli, J. E.

1978-01-01

The requirements of the ideal Stirling cycle, as well as basic types of practical engines are described. Advantages, disadvantages, and problem areas of these Stirling engines are discussed. The potential for ceramic components is also considered. Currently ceramics are used in only two areas, the air preheater and insulating tiles between the burner and the heater head. For the advanced Stirling engine to achieve high efficiency and low cost, the principal components are expected to be made from ceramic materials, including the heater head, air preheater, regenerator, the burner and the power piston. Supporting research and technology programs for ceramic component development are briefly described.

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

Energy Technology Data Exchange (ETDEWEB)

Anstett, P.

2006-07-01

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

锅炉给风管道技改初探%Preliminary Study on the Technological Reform of the Air Feeding Pipe of Boiler

Institute of Scientific and Technical Information of China (English)

常飞

2014-01-01

According to the original design, the air feeding pipe of NO.1 fan and No.2 fan is at the outdoor of the main workshop. The temperature of feeding air is the environmental temperature (The hottest month is24℃and the coldest month is-9.30℃ and the annual average temperature is 8.50℃ ). Now the air inlet is changed to located at the indoor of the boiler room. The heat air in the boiler room is sent to the air preheater through air pipe which improves the temperature of feeding air and improves the burning of the boiler. Thus, the coal is saved and the energy consumption is reduced.%原设计一、二次风机进风管道在主厂房室外，进风温度是环境温度，最热月是24℃，最冷月是-9.30℃，年平均气温是8.50℃；改为进风口放在锅炉房室内，由风管把锅炉房高空热空气(30~40℃)送入空预器，提高给风温度改善锅炉燃烧，节约燃煤，降低能耗。

Air pollution from motor vehicle emissions

International Nuclear Information System (INIS)

Petrushevska, Ljubica

1996-01-01

This paper presents some aspects of air pollution from motor vehicle emissions as: characteristic primary and secondary pollutants, dependence of the motor vehicle emission from the engine type; the relationship of typical engine emission and performance to air-fuel ratio, transport of pollutants from mobile sources of emissions, as well as some world experiences in the control approaches for exhaust emissions. (author)

Physical and mathematical modelling of gas-fired glass melting furnaces with regard to NO-formation

International Nuclear Information System (INIS)

May, F.; Stuchlik, O.; Kremer, H.

1999-01-01

The increasing demand in quality, efficiency, energy conservation and the environmental issues drive the operators of high temperature processes to optimize their furnaces. Especially the glass manufacturing industry with their high working temperatures from about 1850 K to more than 1950 K and high air preheating temperatures of above 1480 K will produce high NOx-concentrations in the flue gas if no primary measures are taken. Considering the three different paths for NO-formation it is obvious that increased thermal NO is responsible for higher emissions. The German environmental regulations on air ''TA Luft'' requires a maximum value of 500 mg/mN3 in the flue gas for most of the combustion processes but for glass melting furnaces a temporary regulation of 1200 mg/mN3 and further on to 800 mg/mN3 is valid. Due to economical reasons the level of secondary measures is to be minimized thus the main objective of research is to reduce the NOx-emissions via primary measures. The design of the furnace is very important due to its strong influence on the distribution of velocity and species. That consequently affects the temperature field and the heat transfer to the load and further on the emissions. For the understanding of the processes within these furnaces numerical simulations, which are successfully validated with experiments, can give valuable indications to optimize furnace design for the reduction of NOx-emissions. The glass melting furnace modelled here is a regenerative horseshoe furnace fired with natural gas. Combustion air is preheated within the regenerator onto a level of temperature of 1650 K. (author)

Aluminum-air battery crystallizer

Science.gov (United States)

Maimoni, A.

1987-01-01

A prototype crystallizer system for the aluminum-air battery operated reliably through simulated startup and shutdown cycles and met its design objectives. The crystallizer system allows for crystallization and removal of the aluminium hydroxide reaction product; it is required to allow steady-state and long-term operation of the aluminum-air battery. The system has to minimize volume and maintain low turbulence and shear to minimize secondary nucleation and energy consumption while enhancing agglomeration. A lamella crystallizer satisfies system constraints.

Engineered Surfaces to Control Secondary Electron Yield for Multipactor Suppression

Science.gov (United States)

2017-09-14

Air Force Institute of Technology AFIT Scholar Theses and Dissertations 9-14-2017 Engineered Surfaces to Control Secondary Electron Yield for...Multipactor Suppression James M. Sattler Follow this and additional works at: https://scholar.afit.edu/etd Part of the Electrical and Electronics Commons... TECHNOLOGY Wright-Patterson Air Force Base, Ohio DISTRIBUTION STATEMENT A. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

Operating experience of a portable thermophotovoltaic power supply

Science.gov (United States)

Becker, Frederick E.; Doyle, Edward F.; Shukla, Kailash

1999-03-01

Two configurations of man-portable thermophotovoltaic (TPV) power supplies based on Thermo Power's supported continuous fiber emitter have been designed, built, and are being tested. The systems use narrow-band, fibrous, ytterbia emitters radiating to bandgap matched silicon photovoltaic arrays with dielectric stack filters for optical energy recovery and recuperators for thermal energy recovery. The systems have been designed for operation with propane and with combustion air preheat temperatures of up to 1250 K. To operate at air preheat temperatures above the auto-ignition temperature of the fuel, a unique fuel delivery system was devised which results in the micromixing and rapid combustion of the fuel and air right in the emitter fibers. This allows the ytterbia emitter fibers to run much hotter (˜2000 K) than any of the surrounding structure.

Heat exchangers of a new design and their use in thermal power engineering

Science.gov (United States)

Astanovskii, D. L.; Astanovskii, L. Z.

2007-07-01

We present a new design of a heat exchanger capable of handling flows of gases and liquids at temperatures from -270 to +1100°C and pressure of up to 30 MPa, for any throughput capacity required, and ensuring low loss of head of heat-transfer media. Examples illustrating the use of such an apparatus for supplying hot water, preheating natural gas, recuperating the heat of stack gases, and preheating air are given.

Air tamponade of the heart.

Science.gov (United States)

Gołota, Janusz J; Orłowski, Tadeusz; Iwanowicz, Katarzyna; Snarska, Jadwiga

2016-06-01

Pneumopericardium is a rare disease defined as the presence of air or gas in the pericardial sac. Among the etiological factors, the following stand out: chest trauma, barotrauma, air-containing fistulas between the pericardium and the surrounding structures, secondary gas production by microorganisms growing in the pericardial sac, and iatrogenic factors. Until now, spontaneous pneumopericardium has been considered a harmless and temporary state, but a review of clinical cases indicates that the presence of air in the pericardium can lead to cardiac tamponade and life-threatening hemodynamic disturbances. We present the case of an 80-year-old patient with a chronic bronchopericardial fistula, who suffered from a cardiac arrest due to air tamponade of the heart.

When Is the Optimal Timing of the Surgical Treatment for Secondary Spontaneous Pneumothorax?

Science.gov (United States)

Jeon, Hyun Woo; Kim, Young-Du; Choi, Si Young; Park, Jae Kil

2017-01-01

Objectives  The definition of spontaneous pneumothorax is accumulation of air in the pleural space, resulting in dyspnea or chest pain. Unlike primary spontaneous pneumothorax, secondary pneumothorax can be a life-threatening condition and spontaneous healing rate is uncommon. Although surgery is the most effective treatment modality for pneumothorax, surgical management and timing is difficult where there is underlying lung disease and/or medical comorbidities. Prolonged air leakage increases the morbidity and mortality in thoracic surgery. We hypothesized that duration of air leakage before operation may lead to increase in complications. Methods  This study is a retrospective review of 155 consecutive patients with air leakage who underwent bullectomy for secondary spontaneous pneumothorax from January 2005 to July 2013. The patients were divided according to the duration of preoperative air leakage. The patients were followed-up until the time of last visit or death. Postoperative morbidity and mortality were assessed and the risk factors for complications were analyzed. Results  The median age was 65 years (range, 52-88) with male predominance (96.13%). The median duration of preoperative air leakage was 6 days (range, 1-30). The median surgery time was 90 minutes (range, 25-300) and median hospital stay after operation was 7 days (range, 3-75). Postoperative complications occurred in 38 patients (24.52%) and postoperative recurrence was shown to have occurred in 8 patients (5.16%). With multivariate analysis, risk factors for postoperative complications were: underlying interstitial lung disease and air leakage > 5 days before operation. Conclusion  Persistent air leakage was a major surgical indication for pneumothorax. Early surgical treatment reduced postoperative complications for secondary spontaneous pneumothorax. Georg Thieme Verlag KG Stuttgart · New York.

Economic application, design analysis, and material availability for ceramic heat exchangers

Science.gov (United States)

Tennery, V. J.

1981-01-01

Fuel consumption in an industrial process can be reduced by 40% or more by using recuperation or regeneration to heat air for the burners compared with use of ambient temperature air for fuel combustion with furnace gases in the range of 1300 C and air preheat temperatures above 800 C. Alloy temperature limitations and corrosion of the alloys severely limit the use of metal recuperators to preheat air above about 600 C. Structural ceramics, such as silicon carbide, offer promise for use in high-temperature HXs for recovering waste heat from hot flue gases. An assessment was made of industrial attitudes toward advanced high-temperature ceramic recuperators. Three promising industrial processes are identified where these recuperators could be applied. Conceptual designs of ceramic recuperators are given consistent with the furnace requirements for these processes. The annual national fuel saving possible for the three applications of these recuperators was estimated.

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.

The impact of environmental inertial stability on the secondary circulation of axisymmetric tropical cyclones

Science.gov (United States)

O'Neill, M. E.; Chavas, D. R.

2017-12-01

In f-plane numerical simulations and analytical theory, tropical cyclones completely recycle their exhausted outflow air back into the boundary layer. This low-angular momentum air must experience cyclonic torque at the sea surface for cyclone to reach equilibrium. On Earth, however, it is not clear that tropical cyclones recycle all of the outflow air in a closed secondary circulation, and strong asymmetric outflow-jet interactions suggest that much of the air may be permanently evacuated from the storm over its lifetime. The fraction of outflow air that is returned to the near-storm boundary layer is in part a function of the environmental inertial stability, which controls the size and strength of the upper anticyclone. We run a suite of idealized axisymmetric tropical cyclone simulations at constant latitude while varying the outer domain's inertial stability profile. Fixing the latitude allows the gradient wind balance of the storm core to remain constant except for changes due to the far environment. By varying both the outer inertial stability and its location with respect to the Rossby radius of deformation, we show how the tropical cyclone's area-of-influence is controlled by the nature and strength of the upper anticyclone. Parcel tracking additionally demonstrates the likelihood of outflow air parcels to be quickly re-consumed by the secondary circulation as a function of inertial stability. These experiments demonstrate the sensitivity of the tropical cyclone's secondary circulation, typically assumed to be closed, to the dynamics of the far environment.

Test and evaluation of the Argonne BPAC10 Series air chamber calorimeter designed for 20 minute measurements

International Nuclear Information System (INIS)

Perry, R.B.; Fiarman, S.; Jung, E.A.; Cremers, T.

1990-10-01

This paper is the final report on DOE-OSS Task ANLE88002 ''Fast Air Chamber Calorimetry.'' The task objective was to design, construct, and test an isothermal air chamber calorimeter for plutonium assay of bulk samples that would meet the following requirements for sample power measurement: average sample measurement time less than 20 minutes. Measurement of samples with power output up to 10 W. Precision of better than 1% RSD for sample power greater than 1 W. Precision better than 0.010 watt SD, for sample power less than 1 W. This report gives a description of the calorimeter hardware and software and discusses the test results. The instrument operating procedure, included as an appendix, gives examples of typical input/output and explains the menu driven software. Sample measurement time of less than 20 minutes was attained by pre-equilibration of the samples in low cost precision preheaters and by prediction of equilibrium measurements. Tests at the TA55 Plutonium Facility at Los Alamos National Laboratory, on typical samples, indicates that the instrument meets all the measurement requirements

Effects of Eutectic Si and Secondary Dendrite Arm Spacing on the Mechanical Properties of Al-Si-Cu Cast Alloys

International Nuclear Information System (INIS)

Lee, Kyungmin; Kim, Yumi; Kim, Youngman; Hong, Sungkil; Choi, Seweon; Kim, Youngchan; Kang, Changseok

2014-01-01

The present study aims at investigating the effects of eutectic Si and Secondary dendrite arm spacing (SDAS) on mechanical properties of Al-Si-Cu alloy. Heat treatment and controlling of solidification rate affect to microstructure of Al-Si-Cu alloy. Al-Si-Cu alloy was dissolved in an electric furnace. The alloy cast in STD61 mold which had been pre-heated to 95 ℃ and 200 ℃. Eutectic Si and SDAS were finer as cooling rate increased. Image analysis technique has been utilized to examine the microstructure. Microstructure observation results showed that T6 heat treatment has a strong influence eutectic Si particle morphology. The mechanical properties, such as tensile strength, yield strength, elongation, were improved by ASTM E8 standard. Tensile properties of the Al-Si-Cu alloys prepared by different cooling rates were the same as each other by T6 heat treatment.

Two-story residence with solar heating--Newman, Georgia

Science.gov (United States)

1981-01-01

Report evaluates performance of warm-air collector system for 11 month period and provides operation and maintenance information. System consists of 14 warm air collectors, rock-storage bin, air handler, heat exchangers, hot-water preheat tank, associated controls, plumbing, and air ducting. Average building temperature was maintained at 72 F (22 C); solar equipment provided 47 percent of space-heating requirement.

Effect of hydrothermal modification on the structure of REY zeolite studied by PAS

International Nuclear Information System (INIS)

Zhu Jun; Wang Shaojie

2003-01-01

The effect of temperature of the hydrothermal modification on the structure of Rare-earth Y zeolite (REY) was studied by positron annihilation spectroscopy. We measured the positron lifetime spectrum as a function of the temperature (300-800 degree C) of one hour hydrothermal modification for the REY zeolite after through pre-heated dehydration at 150 degree C. All lifetime spectra could be resolved into five components. The fifth lifetime component and its intensity were found to be related to the size and number of the secondary pores. The experimental results showed that the secondary pore in REY zeolite was produced by hydrothermal modification in some temperature range, and the largest size and the greatest quantity of the secondary pores were observed in the sample treated at 500 degree C for 1 hour. The effect of hydrothermal modification on REY zeolite without pre-heated dehydration was also discussed

Nanotechnology based surface treatments for corrosion protection and deposit control of power plant equipment. Phase 1

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-05-15

Nanotechnology can provide possibilities for obtaining new valuable information regarding performance and corrosion protection in power plants. In general the desired performance of the contact surfaces is an easy-to-release effect. This is in order to prolong the time interval between cleaning periods or make the cleaning procedures easier and less expensive. Corrosion protection is also desired in order to extend the life time of various parts in the power plants and thus optimize the energy output and overall efficiency of the plant. Functional sol-gel coating based on nanotechnology is tested in a variety of conditions. Applications of functional sol-gel coatings were performed in the condenser and on seven air preheaters at Fynsvaerket, Odense, with corrosion protection as the main issue. Coatings with easy-to-clean effects were tested in the Flue Gas Desulphurization plant at Nordjyllandsvaerket, Aalborg, with the aim of reducing gipsum deposit. Thermo stabilized coatings were tested on tube bundles between in the passage from the 1st to 2end pass and on the wall between 1st and 2end pass at Amagervaerket, Copenhagen, and in the boiler at Haderslev CHP plant. The objective of this test were reducing deposits and increasing corrosion protection. The tested coatings were commercial available coatings and coatings developed in this project. Visual inspections have been performed of all applications except at Nordjyllandsvaerket. Corrosion assessment has been done at DTU - Mechanical Engineering. The results range from no difference between coated and uncoated areas to some improvements. At Amagervaerket the visual assessment showed in general a positive effect with a sol-gel hybrid system and a commercial system regarding removal of deposits. The visual assessment of the air preheaters at Fynsvaerket indicates reduced deposits on a sol-gel nanocomposite coated air preheater compared to an uncoated air preheater. (Author)

Influence of repeated infusion of capsaicin-contained red pepper sauce on esophageal secondary peristalsis in humans.

Science.gov (United States)

Liu, T T; Yi, C H; Lei, W Y; Hung, X S; Yu, H C; Chen, C L

2014-10-01

The transient receptor potential vanilloid 1 has been implicated as a target mediator for heartburn perception and modulation of esophageal secondary peristalsis. Our aim was to determine the effect of repeated esophageal infusion of capsaicin-contained red pepper sauce on heartburn perception and secondary peristalsis in healthy adults. Secondary peristalsis was performed with mid-esophageal injections of air in 15 healthy adults. Two separate protocols including esophageal infusion with saline and capsaicin-contained red pepper sauce and 2 consecutive sessions of capsaicin-contained red pepper sauce were randomly performed. After repeated infusion of capsaicin-contained red pepper sauce, the threshold volume to activate secondary peristalsis was significantly increased during slow (p sauce enhanced heartburn perception (p sauce infusion (p = 0.007). Acute infusion of capsaicin-contained red pepper sauce significantly increased pressure wave amplitudes of distal esophagus during slow (p = 0.003) and rapid air injections (p = 0.01), but repeated infusion of capsaicin-contained red pepper sauce significantly decreased pressure wave amplitude of distal esophagus during slow (p = 0.0005) and rapid air injections (p = 0.003). Repeated esophageal infusion of capsaicin appears to attenuate heartburn perception and inhibit distension-induced secondary peristalsis in healthy adults. These results suggest capsaicin-sensitive afferents in modulating sensorimotor function of secondary peristalsis in human esophagus. © 2014 John Wiley & Sons Ltd.

Emerging large-scale solar heating applications

International Nuclear Information System (INIS)

Wong, W.P.; McClung, J.L.

2009-01-01

Currently the market for solar heating applications in Canada is dominated by outdoor swimming pool heating, make-up air pre-heating and domestic water heating in homes, commercial and institutional buildings. All of these involve relatively small systems, except for a few air pre-heating systems on very large buildings. Together these applications make up well over 90% of the solar thermal collectors installed in Canada during 2007. These three applications, along with the recent re-emergence of large-scale concentrated solar thermal for generating electricity, also dominate the world markets. This paper examines some emerging markets for large scale solar heating applications, with a focus on the Canadian climate and market. (author)

Emerging large-scale solar heating applications

Energy Technology Data Exchange (ETDEWEB)

Wong, W.P.; McClung, J.L. [Science Applications International Corporation (SAIC Canada), Ottawa, Ontario (Canada)

2009-07-01

Currently the market for solar heating applications in Canada is dominated by outdoor swimming pool heating, make-up air pre-heating and domestic water heating in homes, commercial and institutional buildings. All of these involve relatively small systems, except for a few air pre-heating systems on very large buildings. Together these applications make up well over 90% of the solar thermal collectors installed in Canada during 2007. These three applications, along with the recent re-emergence of large-scale concentrated solar thermal for generating electricity, also dominate the world markets. This paper examines some emerging markets for large scale solar heating applications, with a focus on the Canadian climate and market. (author)

Flat plate solar collector for water pre-heating using concentrated solar power (CSP)

Science.gov (United States)

Peris, Leonard Sunny; Shekh, Md. Al Amin; Sarker, Imran

2017-12-01

Numerous attempt and experimental conduction on different methods to harness energy from renewable sources are being conducted. This study is a contribution to the purpose of harnessing solar energy as a renewable source by using flat plate solar collector medium to preheat water. Basic theory of solar radiation and heat convection in water (working fluid) has been combined with heat conduction process by using copper tubes and aluminum absorber plate in a closed conduit, covered with a glazed through glass medium. By this experimental conduction, a temperature elevation of 35°C in 10 minutes duration which is of 61.58% efficiency range (maximum) has been achieved. The obtained data and experimental findings are validated with the theoretical formulation and an experimental demonstration model. A cost effective and simple form of heat energy extraction method for space heating/power generation has been thoroughly discussed with possible industrial implementation possibilities. Under-developed and developing countries can take this work as an illustration for renewable energy utilization for sustainable energy prospect. Also a full structure based data to derive concentrated solar energy in any geographical location of Bangladesh has been outlined in this study. These research findings can contribute to a large extent for setting up any solar based power plant in Bangladesh irrespective of its installation type.

Cerebral Venous Air Embolism due to a Hidden Skull Fracture Secondary to Head Trauma

Directory of Open Access Journals (Sweden)

Ai Hosaka

2015-01-01

Full Text Available Cerebral venous air embolism is sometimes caused by head trauma. One of the paths of air entry is considered a skull fracture. We report a case of cerebral venous air embolism following head trauma. The patient was a 55-year-old man who fell and hit his head. A head computed tomography (CT scan showed the air in the superior sagittal sinus; however, no skull fractures were detected. Follow-up CT revealed a fracture line in the right temporal bone. Cerebral venous air embolism following head trauma might have occult skull fractures even if CT could not show the skull fractures.

Installation package - SIMS prototype system 1A

Science.gov (United States)

1976-01-01

This report consists of details for the installation, operation and maintenance of a prototype heating and hot water system, designed for residential or light commercial applications. This system consists of the following subsystems: air type collectors, pebble bed thermal storage, air handling unit, air to water heat exchanger, hot water preheat tank, auxiliary energy, ducting system.

Solar energy system performance evaluation report for IBM System 4 at Clinton, Mississippi

Science.gov (United States)

1980-07-01

The IBM System 4 Solar Energy System is described and evaluated. The system was designed to provide 35 percent of the space heating and 63 percent of the domestic hot water preheating for a single family residence located within the United States. The system consists of 259 square feet of flat plate air collectors, a rock thermal storage containing 5 1/2 ton of rock, heat exchangers, blowers, a 52 gallon preheat tank, controls, and associated plumbing. In general, the performance of the system did not meet design expectations, since the overall design solar fraction was 48 percent and the measured value was 32 percent. Although the measured space heating solar fraction at 32 percent did agree favorably with the design space heating solar fraction at 35 percent, the hot water measured solar fraction at 33 percent did not agree favorably with the design hot water solar fraction of 63 percent. In particular collector array air leakage, dust covered collectors, abnormal hot water demand, and the preheat tank by pass valve problem are main reasons for the lower performance.

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

International Nuclear Information System (INIS)

Tang, Dapei

2015-01-01

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. (paper)

The Energy Efficiency of Hot Water Production by Gas Water Heaters with a Combustion Chamber Sealed with Respect to the Room

Directory of Open Access Journals (Sweden)

Grzegorz Czerski

2014-08-01

Full Text Available This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energy efficiency of hot water production. CFD (Computational Fluid Dynamics software was used for calculation of the heat exchange in this kind of system. The studies and calculations have shown that the use of gas water heaters with a combustion chamber sealed with respect to the room significantly increases the efficiency of hot water production when compared to traditional heaters. It has also been proven that the pre-heating of combustion air in concentric chimney and air supply ducts essentially improves the energy efficiency of gas appliances for hot water production.

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.)

Incidence of secondary aeration in confined flames of high pressure premixed atmospheric burner

International Nuclear Information System (INIS)

Cadavid Sierra, Francisco Javier; Buitrago Garcia, Jorge Enrique; Velasquez, Daniel

2002-01-01

In this work an experimental study about the variables that affect the secondary aeration has been applied. The relationships with phenomena that affect the proper operation of the combustion chamber are discussed in detail. These phenomena are quenching, flame stabilization and the combustion product recirculation. A flexible combustion system developed to allow variations in the volume of combustion chamber, the area of secondary air entrance, the outlet of combustion products and the thermal output is presented. Also, the system could vary the inlet of primary air, though the study is carried out with maximal working area. The experimental setup allowed to compare and to find the influence of design parameters mentioned above on the secondary aeration and also to obtain the insight that the most important design parameters were combustion product outlet and the combustion intensity

Differences in the Control of Secondary Peristalsis in the Human Esophagus: Influence of the 5-HT4 Receptor versus the TRPV1 Receptor.

Directory of Open Access Journals (Sweden)

Chih-Hsun Yi

Full Text Available Acute administration of 5-hydroxytryptamine4 (5-HT4 receptor agonist, mosapride or esophageal infusion of the transient receptor potential vanilloid receptor-1 (TRPV1 agonist capsaicin promotes secondary peristalsis. We aimed to investigate whether acute esophageal instillation of capsaicin-containing red pepper sauce or administration of mosapride has different effects on the physiological characteristics of secondary peristalsis.Secondary peristalsis was induced with mid-esophageal air injections in 14 healthy subjects. We compared the effects on secondary peristalsis subsequent to capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg or 40 mg oral mosapride.The threshold volume for generating secondary peristalsis during slow air distensions was significantly decreased with capsaicin infusion compared to mosapride (11.6 ± 1.0 vs. 14.1 ± 0.8 mL, P = 0.02. The threshold volume required to produce secondary peristalsis during rapid air distension was also significantly decreased with capsaicin infusion (4.6 ± 0.5 vs. 5.2 ± 0.6 mL, P = 0.02. Secondary peristalsis was noted more frequently in response to rapid air distension after capsaicin infusion than mosapride (80% [60-100%] vs. 65% [5-100%], P = 0.04. Infusion of capsaicin or mosapride administration didn't change any parameters of primary or secondary peristalsis.Esophageal infusion with capsaicin-containing red pepper sauce suspension does create greater mechanosensitivity as measured by secondary peristalsis than 5-HT4 receptor agonist mosapride. Capsaicin-sensitive afferents appear to be more involved in the sensory modulation of distension-induced secondary peristalsis.

Utilization of secondary energy - major uses in the fermentation and beverage industries

Energy Technology Data Exchange (ETDEWEB)

Koch, H J

1986-01-01

With 18,5% the fermentation and beverage industry (not including liquors, wine and champagne) has the highest share of energy consumption within the food industry. At the same time, these two branches dispose of high secondary energy potentials which remain to be exploited yet. Secondary energy utilization primarily consists in the economic cooling of wort providing for the utilization of process water (80-82/sup 0/C), utilization of air-containing or air-void water vapors from wort boiling processes for technological heating processes, utilization of refrigerator super-heat enthalpies, the use of energy, conserving high-short heaters for larger units, in particular, and utilization of flue gas enthalpies with gaseous energy sources as the most efficient ones.

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

Science.gov (United States)

Singh, A. I. Clifford

1988-01-01

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

75 FR 81126 - Revisions to Lead Ambient Air Monitoring Requirements

Science.gov (United States)

2010-12-27

... tons per year of lead is necessary to provide sufficient information about airborne lead levels near... Revisions to Lead Ambient Air Monitoring Requirements AGENCY: Environmental Protection Agency (EPA). ACTION...) that revised the primary and secondary National Ambient Air Quality Standards (NAAQS) for lead and...

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

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

Science.gov (United States)

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

2017-08-01

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

Overview of Megacity Air Pollutant Emissions and Impacts

Science.gov (United States)

Kolb, C. E.

2013-05-01

The urban metabolism that characterizes major cities consumes very large qualities of humanly produced and/or processed food, fuel, water, electricity, construction materials and manufactured goods, as well as, naturally provided sunlight, precipitation and atmospheric oxygen. The resulting urban respiration exhalations add large quantities of trace gas and particulate matter pollutants to urban atmospheres. Key classes of urban primary air pollutants and their sources will be reviewed and important secondary pollutants identified. The impacts of these pollutants on urban and downwind regional inhabitants, ecosystems, and climate will be discussed. Challenges in quantifying the temporally and spatially resolved urban air pollutant emissions and secondary pollutant production rates will be identified and possible measurement strategies evaluated.

Progress Toward Analytic Predictions of Supersonic Hydrocarbon-Air Combustion: Computation of Ignition Times and Supersonic Mixing Layers

Science.gov (United States)

Sexton, Scott Michael

Combustion in scramjet engines is faced with the limitation of brief residence time in the combustion chamber, requiring fuel and preheated air streams to mix and ignite in a matter of milliseconds. Accurate predictions of autoignition times are needed to design reliable supersonic combustion chambers. Most efforts in estimating non-premixed autoignition times have been devoted to hydrogen-air mixtures. The present work addresses hydrocarbon-air combustion, which is of interest for future scramjet engines. Computation of ignition in supersonic flows requires adequate characterization of ignition chemistry and description of the flow, both of which are derived in this work. In particular, we have shown that activation energy asymptotics combined with a previously derived reduced chemical kinetic mechanism provides analytic predictions of autoignition times in homogeneous systems. Results are compared with data from shock tube experiments, and previous expressions which employ a fuel depletion criterion. Ignition in scramjet engines has a strong dependence on temperature, which is found by perturbing the chemically frozen mixing layer solution. The frozen solution is obtained here, accounting for effects of viscous dissipation between the fuel and air streams. We investigate variations of thermodynamic and transport properties, and compare these to simplified mixing layers which neglect these variations. Numerically integrating the mixing layer problem reveals a nonmonotonic temperature profile, with a peak occurring inside the shear layer for sufficiently high Mach numbers. These results will be essential in computation of ignition distances in supersonic combustion chambers.

Development program for MHD power generation. Interim technical report June 1974

International Nuclear Information System (INIS)

1974-06-01

A total of 33,000 kilowatt hours of accumulated operating experience has been built up on the Mark VI MHD generator experiment. A total absence of arcing during the last 68 hours indicates that this major determinant of long-duration reliability has been brought under control, and a new Avco-designed burner has been put in service which has made possible, on a routine basis, power-levels in the Mark VI of from 400 to 500 kilowatts. A metal tubular air preheater and compressor have been ordered for the purpose of reducing the hourly consumption of liquid oxidizer, thus allowing more hours of operation between refills. Testing of the high-temperature air heater has also yielded highly satisfactory results. To date, air preheat temperatures of 3000 0 F and higher have been reached in continuous cyclic operation for more than 600 hours. Alumina cored brick is the heater matrix and the mode of operation corresponds to separate firing. Air preheat temperature strongly influences the overall efficiency of an MHD plant and an efficiency of between 55-60 percent is possible with the performance obtained to date. Detailed analysis of the radiation cooling and kinetics of the MHD generator exhaust gas in the radiant section of the downstream boiler, have shown that the level of NO/sub x/ can be reduced to a fraction of the corresponding EPA standard in a furnace of reasonable size

Measurement of gas species, temperatures, char burnout, and wall heat fluxes in a 200-MW{sub e} lignite-fired boiler at different loads

Energy Technology Data Exchange (ETDEWEB)

Li, Zhengqi; Jing, Jianping; Liu, Guangkui; Chen, Zhichao; Liu, Chunlong [School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001 (China)

2010-04-15

We measured various operational parameters of a 200-MW{sub e}, wall-fired, lignite utility boiler under different loads. The parameters measured were gas temperature, gas species concentration, char burnout, component release rates (C, H and N), furnace temperature, heat flux, and boiler efficiency. Cold air experiments of a single burner were conducted in the laboratory. A double swirl flow pulverized-coal burner has two ring recirculation zones that start in the secondary air region of the burner. With increasing secondary air flow, the air flow axial velocity increases, the maximum values for the radial velocity, tangential velocity, and turbulence intensity all increase, and there are slight increases in the air flow swirl intensity and the recirculation zone size. With increasing load gas, the temperature and CO concentration in the central region of burner decrease, while O{sub 2} concentration, NO{sub x} concentration, char burnout, and component release rates of C, H, and N increase. Pulverized-coal ignites farther into the burner, in the secondary air region. Gas temperature, O{sub 2} concentration, NO{sub x} concentration, char burnout and component release rates of C, H, and N all increase. Furthermore, CO concentration varies slightly and pulverized-coal ignites closer. In the side wall region, gas temperature, O{sub 2} concentration, and NO{sub x} concentration all increase, but CO concentration varies only slightly. In the bottom row burner region the furnace temperature and heat flux increase appreciably, but the increase become more obvious in the middle and top row burner regions and in the burnout region. Compared with a 120-MW{sub e} load, the mean NO{sub x} emission at the air preheater exits for 190-MW{sub e} load increases from 589.5 mg/m{sup 3} (O{sub 2} = 6%) to 794.6 mg/m{sup 3} (O{sub 2} = 6%), and the boiler efficiency increases from 90.73% to 92.45%. (author)

DEFENSE INVENTORY: Improved Management Framework Needed to Guide Air Force Best Practice Initiatives

National Research Council Canada - National Science Library

1999-01-01

In this report, we discuss our evaluation of the Air Force's best practices implementation schedule for the acquisition and distribution of secondary inventory items, which the Secretary of the Air...

Secondary structure of spiralin in solution, at the air/water interface, and in interaction with lipid monolayers.

Science.gov (United States)

Castano, Sabine; Blaudez, Daniel; Desbat, Bernard; Dufourcq, Jean; Wróblewski, Henri

2002-05-03

The surface of spiroplasmas, helically shaped pathogenic bacteria related to the mycoplasmas, is crowded with the membrane-anchored lipoprotein spiralin whose structure and function are unknown. In this work, the secondary structure of spiralin under the form of detergent-free micelles (average Stokes radius, 87.5 A) in water and at the air/water interface, alone or in interaction with lipid monolayers was analyzed. FT-IR and circular dichroism (CD) spectroscopic data indicate that spiralin in solution contains about 25+/-3% of helices and 38+/-2% of beta sheets. These measurements are consistent with a consensus predictive analysis of the protein sequence suggesting about 28% of helices, 32% of beta sheets and 40% of irregular structure. Brewster angle microscopy (BAM) revealed that, in water, the micelles slowly disaggregate to form a stable and homogeneous layer at the air/water interface, exhibiting a surface pressure up to 10 mN/m. Polarization modulation infrared reflection absorption spectroscopy (PMIRRAS) spectra of interfacial spiralin display a complex amide I band characteristic of a mixture of beta sheets and alpha helices, and an intense amide II band. Spectral simulations indicate a flat orientation for the beta sheets and a vertical orientation for the alpha helices with respect to the interface. The combination of tensiometric and PMIRRAS measurements show that, when spiroplasma lipids are used to form a monolayer at the air/water interface, spiralin is adsorbed under this monolayer and its antiparallel beta sheets are mainly parallel to the polar-head layer of the lipids without deep perturbation of the fatty acid chains organization. Based upon these results, we propose a 'carpet model' for spiralin organization at the spiroplasma cell surface. In this model, spiralin molecules anchored into the outer leaflet of the lipid bilayer by their N-terminal lipid moiety are composed of two colinear domains (instead of a single globular domain) situated at

Seawater feed reverse osmosis preheating appraisal, Part I: leading element performance

International Nuclear Information System (INIS)

Karameldin, A.; Saadawy, M.S.

2006-01-01

This paper is concerned with the seawater reverse osmosis preheating process, and presents a parametric study of the process. The basic transport equations describing the leading element are exhibited and appraised. The leading element, which governs the whole system performance, is studied and analysed. The incorporated and investigated operating parameters are the feed pressure and the temperature for different feed salt concentrations. In addition, different feed flow rates, effects on permeate flux and permeator salt rejection, together with the permeator recovery, are studied. A seawater membrane of a well-known data, for instance FT30SW380HR, is used to perform the study. The membrane water permeability coefficient K w is determined and correlated. Furthermore, the membrane salt permeability coefficient K s from the manufacturer system analysis program (ROSA) is given and discussed. The transport governing equations are programmed in a way that facilitates the achievement of a realistic parametric study. The results showed that the permeate flux increases significantly as the feed pressure increases. Also, it increases significantly as the feed salt concentration decreases, and also as the feed temperature and pressure increase. Meanwhile, the permeator salt rejection increases significantly as the feed pressure increases, and decreases significantly as the feed temperature increases. The study of the leading element of the array showed that there are constraints that must be considered, such as maximum membrane flux, maximum applied feed pressure, maximum feed flow rate and maximum feed temperature. Therefore, to attain the maximum membrane flux, the applied feed pressure must be lowered when the feed temperature is increased. In the case where the feed temperature is increased from 18 deg.. C to 45 deg.. C, a pressure saving of between 7% and 26% is achieved, according to the feed salt concentration and feed flow rate. (author)

Increase in the boiler's performance in terms of the acid dew point temperature: Environmental advantages of replacing fuels

Energy Technology Data Exchange (ETDEWEB)

Blanco, J.M.; Pena, F. [Dpto. Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieria, Universidad del Pais Vasco/E.H.U., Alameda de Urquijo s/n (48013) Bilbao (Spain)

2008-05-15

The aim of air pre-heaters is to raise the temperature of the combustion air in boilers, using heat recovered from the power plant combustion gases. On the one hand, this paper compares the effects of the acid dew point temperature (ADT) on pre-heaters in a reference thermal power plant for two types of fuel, ''fuel No. 2'' and ''low sulphur fuel'' respectively and on the other hand, it shows how a changeover to this latter fuel would increase the useful lifetime of this equipment, reducing this way cost of maintenance due to the considerable decrease in the area exposed to ADT with the subsequent increase in the boiler's performance. (author)

Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

Science.gov (United States)

1980-01-01

The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

Science.gov (United States)

1980-07-01

The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

Ozone and limonene in indoor air: a source of submicron particle exposure.

Science.gov (United States)

Wainman, T; Zhang, J; Weschler, C J; Lioy, P J

2000-12-01

Little information currently exists regarding the occurrence of secondary organic aerosol formation in indoor air. Smog chamber studies have demonstrated that high aerosol yields result from the reaction of ozone with terpenes, both of which commonly occur in indoor air. However, smog chambers are typically static systems, whereas indoor environments are dynamic. We conducted a series of experiments to investigate the potential for secondary aerosol in indoor air as a result of the reaction of ozone with d-limonene, a compound commonly used in air fresheners. A dynamic chamber design was used in which a smaller chamber was nested inside a larger one, with air exchange occurring between the two. The inner chamber was used to represent a model indoor environment and was operated at an air exchange rate below 1 exchange/hr, while the outer chamber was operated at a high air exchange rate of approximately 45 exchanges/hr. Limonene was introduced into the inner chamber either by the evaporation of reagent-grade d-limonene or by inserting a lemon-scented, solid air freshener. A series of ozone injections were made into the inner chamber during the course of each experiment, and an optical particle counter was used to measure the particle concentration. Measurable particle formation and growth occurred almost exclusively in the 0.1-0.2 microm and 0.2-0.3 microm size fractions in all of the experiments. Particle formation in the 0.1-0.2 microm size range occurred as soon as ozone was introduced, but the formation of particles in the 0.2-0.3 microm size range did not occur until at least the second ozone injection occurred. The results of this study show a clear potential for significant particle concentrations to be produced in indoor environments as a result of secondary particle formation via the ozone-limonene reaction. Because people spend the majority of their time indoors, secondary particles formed in indoor environments may make a significant contribution to

Air contamination analysis during emergency medical treatment

International Nuclear Information System (INIS)

Yamada, Y.; Fukutsu, K.; Yuuki, M.; Akashi, M.

2009-01-01

After radiological emergencies, patients contaminated with radioactivity are taken to radiation emergency hospitals for treatment. Numerical simulations using the computer software 'Flow Designer R were made in order to evaluate indoor air contamination caused by the breathing out of contaminated air. The National Inst. of Radiological Sciences facility was used for the numerical evaluation. Results indicate that the dispersion of contaminated air depends on the characteristics of the contaminants, and that the dispersion range was limited and localised. Only medical staff standing in a special position near the patient was exposed to almost un-diluted contaminated air. Highly contaminated air was evacuated with a local exhaust pump system. Room air quality was monitored using a continuous air sampling system, but it was found that the sampling point was not representative for the purpose of radiation protection. From the air-flow analysis, some problems that affect radiological safety were revealed and valuable information and measures for preventing secondary contamination were determined. (authors)

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

Science.gov (United States)

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

2012-01-01

The authors examined whether air pollution at school (nitrogen dioxide) is associated with poorer child cognition and health and whether adjustment for air pollution explains or moderates previously observed associations between aircraft and road traffic noise at school and children's cognition in the 2001–2003 Road Traffic and Aircraft Noise Exposure and Children's Cognition and Health (RANCH) project. This secondary analysis of a subsample of the United Kingdom RANCH sample examined 719 children who were 9–10 years of age from 22 schools around London's Heathrow airport for whom air pollution data were available. Data were analyzed using multilevel modeling. Air pollution exposure levels at school were moderate, were not associated with a range of cognitive and health outcomes, and did not account for or moderate associations between noise exposure and cognition. Aircraft noise exposure at school was significantly associated with poorer recognition memory and conceptual recall memory after adjustment for nitrogen dioxide levels. Aircraft noise exposure was also associated with poorer reading comprehension and information recall memory after adjustment for nitrogen dioxide levels. Road traffic noise was not associated with cognition or health before or after adjustment for air pollution. Moderate levels of air pollution do not appear to confound associations of noise on cognition and health, but further studies of higher air pollution levels are needed. PMID:22842719

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

Science.gov (United States)

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

2012-08-15

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

Origins and Scaling of Hot-Electron Preheat in Ignition-Scale Direct-Drive Inertial Confinement Fusion Experiments

Science.gov (United States)

Rosenberg, M. J.; Solodov, A. A.; Myatt, J. F.; Seka, W.; Michel, P.; Hohenberger, M.; Short, R. W.; Epstein, R.; Regan, S. P.; Campbell, E. M.; Chapman, T.; Goyon, C.; Ralph, J. E.; Barrios, M. A.; Moody, J. D.; Bates, J. W.

2018-01-01

Planar laser-plasma interaction (LPI) experiments at the National Ignition Facility (NIF) have allowed access for the first time to regimes of electron density scale length (˜500 to 700 μ m ), electron temperature (˜3 to 5 keV), and laser intensity (6 to 16 ×1014 W /cm2 ) that are relevant to direct-drive inertial confinement fusion ignition. Unlike in shorter-scale-length plasmas on OMEGA, scattered-light data on the NIF show that the near-quarter-critical LPI physics is dominated by stimulated Raman scattering (SRS) rather than by two-plasmon decay (TPD). This difference in regime is explained based on absolute SRS and TPD threshold considerations. SRS sidescatter tangential to density contours and other SRS mechanisms are observed. The fraction of laser energy converted to hot electrons is ˜0.7 % to 2.9%, consistent with observed levels of SRS. The intensity threshold for hot-electron production is assessed, and the use of a Si ablator slightly increases this threshold from ˜4×10 14 to ˜6 ×1014 W /cm2 . These results have significant implications for mitigation of LPI hot-electron preheat in direct-drive ignition designs.

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)

METHANE de-NOX for Utility PC Boilers

Energy Technology Data Exchange (ETDEWEB)

Bruce Bryan; Serguei Nester; Joseph Rabovitser; Stan Wohadlo

2005-09-30

to minimize the need for overfire air by maximizing NO{sub x} reduction in the burner. The proposed combustion concept aims to greatly reduce NO{sub x} emissions by incorporating a novel modification to conventional or low-NO{sub x} PC burners using gas-fired coal preheating to destroy NO{sub x} precursors and prevent NO{sub x} formation. A concentrated PC stream enters the burner, where flue gas from natural gas combustion is used to heat the PC up to about 1500 F prior to coal combustion. Secondary fuel consumption for preheating is estimated to be 3 to 5% of the boiler heat input. This thermal pretreatment releases coal volatiles, including fuel-bound nitrogen compounds into oxygen-deficient atmosphere, which converts the coal-derived nitrogen compounds to molecular N{sub 2} rather than NO. Design, installation, shakedown, and testing on Powder River Basin (PRB) coal at a 3-million Btu/h pilot system at RPI's (Riley Power, Inc.) pilot-scale combustion facility (PSCF) in Worcester, MA demonstrated that the PC PREHEAT process has a significant effect on final O{sub x} formation in the coal burner. Modifications to both the pilot system gas-fired combustor and the PC burner led to NO{sub x} reduction with PRB coal to levels below 0.15 lb/million Btu with CO in the range of 35-112 ppmv without any furnace air staging.

Thermal comfort and indoor air quality in rooms with integrated personalized ventilation and under-floor air distribution systems

DEFF Research Database (Denmark)

Li, Ruixin; Sekhar ., S. C.; Melikov, Arsen Krikor

2011-01-01

A comprehensive study comprising physical measurements and human subject experiments was conducted to explore the potential for improving occupants' thermal comfort and indoor air quality (IAQ) using a personalized ventilation (PV) system combined with an under-floor air distribution(UFAD) system....... The integrated PV-UFAD system, when operated at relatively high temperature of the air supplied from the UFAD system, provided comfortable cooling of the facial region, improved inhaled air quality, and decreased the risk of "cold feet," which is often reported in rooms with UFAD alone. This article explores...... and a secondary AHU for 100% recirculated air that is supplied through UFAD outlets. Velocity and temperature distribution in the chamber were measured. A breathing thermal manikin was used to measure the heat loss from 26 body segments and to determine the equivalent temperature. The responses of 30 human...

Air-Freshener Burns: A New Paradigm in Burns Etiology?

OpenAIRE

Sarwar, Umran; Nicolaou, M.; Khan, M. S.; Tiernan, E.

2011-01-01

Objectives: We report a rare case of burns following the use of automated air-fresheners. Methods: We present a case report with a brief overview of the literature relating to burns associated with air-fresheners. The mechanism and treatment of these types of injuries are also described. Results: A 44 year-old female was admitted under the care of the burns team following burns secondary to an exploding air-freshener canister. The patient sustained burns to the face, thorax and arms re...

Low-temperature baseboard heaters with integrated air supply - An analytical and numerical investigation

Energy Technology Data Exchange (ETDEWEB)

Ploskic, Adnan; Holmberg, Sture [Fluid and Climate Technology, School of Architecture and Built Environment, KTH, Marinens vaeg 30, SE-13640 Handen, Stockholm (Sweden)

2011-01-15

The functioning of a hydronic baseboard heating system with integrated air supply was analyzed. The aim was to investigate thermal performance of the system when cold outdoor (ventilation) airflow was forced through the baseboard heater. The performance of the system was evaluated for different ventilation rates at typical outdoor temperatures during the Swedish winter season. Three different analytical models and Computational Fluid Dynamics (CFD) were used to predict the temperature rise of the airflow inside the baseboard heater. Good agreement between numerical (CFD) and analytical calculations was obtained. Calculations showed that it was fully possible to pre-heat the incoming airflow to the indoor temperature and to cover transmission losses, using 45 C supply water flow. The analytical calculations also showed that the airflow per supply opening in the baseboard heater needed to be limited to 7.0 l/s due to pressure losses inside the channel. At this ventilation rate, the integrated system with one air supply gave about 2.1 more heat output than a conventional baseboard heating system. CFD simulations also showed that the integrated system was capable of countering downdraught created by 2.0 m high glazed areas and a cold outdoor environment. Draught discomfort in the case with the conventional system was slightly above the recommended upper limit, but heat distribution across whole analyzed office space was uniform for both heating systems. It was concluded that low-temperature baseboard heating systems with integrated air supply can meet both international comfort requirements, and lead to energy savings in cold climates. (author)

Radioactive gaseous waste processing device

International Nuclear Information System (INIS)

Maruki, Shin-ichiro.

1991-01-01

Radioactive off-gases extracted from a turbine main condensator by using an air extractor flown by way of an off-gas preheater and enter to an off-gas recombiner. Hydrogen in the off-gases is combined with oxygen into steams by the effect of catalysts in the off-gas recombiner. In this case, the off-gases are heated to a high temperature by the reaction heat due to the effect of the catalysts and discharged from the exit of the off-gas recombiner. The off-gases at a high temperature are returned once to the off-gas preheater at the upstream to be used as a heat source for the off-gas preheater. With such a constitution, since the amount of heat for exchange required for heating to about 160degC can be supplied, a heated steam supply device which has been disposed to the off-gas preheater can be saved. Further, the off-gases cooled through heat exchange upon heating the off-gas preheater are flown to the off-gas condensator and the steams are returned into the condensates. Since cooled off-gases enter into a cooling water supply device, the load thereof can be reduced compared with a conventional case. (T.M.)

Simulating urban-scale air pollutants and their predicting capabilities over the Seoul metropolitan area.

Science.gov (United States)

Park, Il-Soo; Lee, Suk-Jo; Kim, Cheol-Hee; Yoo, Chul; Lee, Yong-Hee

2004-06-01

Urban-scale air pollutants for sulfur dioxide, nitrogen dioxide, particulate matter with aerodynamic diameter > or = 10 microm, and ozone (O3) were simulated over the Seoul metropolitan area, Korea, during the period of July 2-11, 2002, and their predicting capabilities were discussed. The Air Pollution Model (TAPM) and the highly disaggregated anthropogenic and the biogenic gridded emissions (1 km x 1 km) recently prepared by the Korean Ministry of Environment were applied. Wind fields with observational nudging in the prognostic meteorological model TAPM are optionally adopted to comparatively examine the meteorological impact on the prediction capabilities of urban-scale air pollutants. The result shows that the simulated concentrations of secondary air pollutant largely agree with observed levels with an index of agreement (IOA) of >0.6, whereas IOAs of approximately 0.4 are found for most primary pollutants in the major cities, reflecting the quality of emission data in the urban area. The observationally nudged wind fields with higher IOAs have little effect on the prediction for both primary and secondary air pollutants, implying that the detailed wind field does not consistently improve the urban air pollution model performance if emissions are not well specified. However, the robust highest concentrations are better described toward observations by imposing observational nudging, suggesting the importance of wind fields for the predictions of extreme concentrations such as robust highest concentrations, maximum levels, and >90th percentiles of concentrations for both primary and secondary urban-scale air pollutants.

Heat exchangers and recuperators for high temperature waste gases

Science.gov (United States)

Meunier, H.

General considerations on high temperature waste heat recovery are presented. Internal heat recovery through combustion air preheating and external heat recovery are addressed. Heat transfer and pressure drop in heat exchanger design are discussed.

Secondary limits of exposure in facilities handling uranium

International Nuclear Information System (INIS)

Raghavayya, M.

1999-08-01

Annual limits of exposure and intake for radiation workers in nuclear installations have been recommended by the International Commission on Radiological Protection and the same have been adopted by the Indian Atomic Energy Regulatory Board for all the radionuclides of interest. The prescribed limits cannot be directly used for day to day radiation protection work. Hence secondary limits have to be derived for routine applications. The modeling steps may be simple in some situations and more complicated in some others. The limits recommended are for individual radionuclides. But in facilities handling natural or enriched uranium the radionuclides (isotopes of uranium and its decay products) generally occur together in specific ratios. Derivation of secondary limits has to take this into consideration. The present document is an attempt at deriving the secondary limits required for routine application in facilities handling uranium (Mine, mill, refineries and fuel fabrication etc.). Secondary limits of exposure have been derived in this document for air borne activity, activity in water, surface contamination and internal exposures. (author)

Secondary Aluminum National Emission Standards for Hazardous Air Pollutants (NESHAP) Applicability Flowcharts

Science.gov (United States)

This March 2003 document contains three diagrams that that are intended to assist you in determining whether you own or operate any equipment that is subject to the NESHAP for Secondary Aluminum Production Facilities.

75 FR 32293 - Revisions to the California State Implementation Plan, South Coast Air Quality Management District

Science.gov (United States)

2010-06-08

... the California State Implementation Plan, South Coast Air Quality Management District AGENCY... approve revisions to the South Coast Air Quality Management District (SCAQMD) portion of the California... submit regulations that control the primary and secondary National Ambient Air Quality Standards (NAAQS...

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

Science.gov (United States)

2011-05-27

... the California State Implementation Plan, South Coast Air Quality Management District AGENCY... the South Coast Air Quality Management District (SCAQMD) portion of the California State... overwhelmingly formed as a secondary pollutant. (South Coast 2007 Air Quality Management Plan, page ES-9...

The Interplay of Climate Change and Air Pollution on Health

OpenAIRE

Orru, H.; Ebi, K. L.; Forsberg, B.

2017-01-01

Purpose of review: Air pollution significantly affects health, causing up to 7 million premature deaths annually with an even larger number of hospitalizations and days of sick leave. Climate change could alter the dispersion of primary pollutants, particularly particulate matter, and intensify the formation of secondary pollutants, such as near-surface ozone. The purpose of the review is to evaluate the recent evidence on the impacts of climate change on air pollution and air pollution-relat...

Assessment of power deposition dependence on the antenna poloidal extension in the fast waves-plasma interaction in pre-heated spherical tokamaks

Energy Technology Data Exchange (ETDEWEB)

Komoshvili, K [Tel Aviv University, Ramat Aviv (Israel); Cuperman, S [Tel Aviv University, Ramat Aviv (Israel); Bruma, C [Tel Aviv University, Ramat Aviv (Israel)

2007-09-15

To assess the effect of antenna poloidal extension on fast waves-plasma interactions in pre-heated spherical tokamaks and, as a result, to assist the determination of optimal conditions for power deposition, we carried out a global, numerical investigation. Thus, we solved the steady-state full wave equations for Alfvenic modes in an inhomogeneous, non-uniformly magnetized, resistive, low aspect ratio tokamak plasma with appropriate consideration of boundary conditions; in this, processes such as wave propagation, reflection, transmission, absorption and mode conversion as well as mode-coupling(s) by plasma cross-section non-homogeneity generated waves were included. The results were analysed in terms of the directions of the current densities generated in the presence of up low field side or down high field side magnetic field gradient. Suitable antenna location and poloidal extension for maximum power deposition were determined.

Assessment of power deposition dependence on the antenna poloidal extension in the fast waves-plasma interaction in pre-heated spherical tokamaks

International Nuclear Information System (INIS)

Komoshvili, K; Cuperman, S; Bruma, C

2007-01-01

To assess the effect of antenna poloidal extension on fast waves-plasma interactions in pre-heated spherical tokamaks and, as a result, to assist the determination of optimal conditions for power deposition, we carried out a global, numerical investigation. Thus, we solved the steady-state full wave equations for Alfvenic modes in an inhomogeneous, non-uniformly magnetized, resistive, low aspect ratio tokamak plasma with appropriate consideration of boundary conditions; in this, processes such as wave propagation, reflection, transmission, absorption and mode conversion as well as mode-coupling(s) by plasma cross-section non-homogeneity generated waves were included. The results were analysed in terms of the directions of the current densities generated in the presence of up low field side or down high field side magnetic field gradient. Suitable antenna location and poloidal extension for maximum power deposition were determined

Aqueous lithium air batteries

Science.gov (United States)

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

2017-05-23

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

Accumulation of selected elements in the pharyngeal tonsils of children as a result of secondary dust emission

Directory of Open Access Journals (Sweden)

Maria Gerycka

2014-09-01

Full Text Available Background. The aim of the study was to determine the influence of secondary dust and car emission on the intoxication of adenoids. Material and methods. The amount of Pb, Be, Ba, Ca, Mg and Sr in pharyngeal tonsils of children living in Tychy (n 86, and in Chorzów (n 76 as well as the amount of the selected elements in suspended dust was determined by the ICP – AES method. The biological material had previously been subjected to mineralization using of nitric acid (V spectrally pure Merck. Results. Secondary emission as a potential additional source of trace elements in tonsils is described by secondary emission coefficient and by the additional weight of the metal present in general air pollution. Conclusions. The degree of accumulation of analyzed elements in the adenoid tissue mostly depends on the content of these elements in soluble form in suspended dust in the ground layer of air, as a result of secondary and car emissions.

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

International Nuclear Information System (INIS)

Teixeira, D.P.

1993-02-01

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

EELV Secondary Payload Adapter (ESPA)

Science.gov (United States)

Haskett, Scott A.; Weis, Steven C.; Doggrell, Leslie J.; Sciulli, Dino; Meink, Troy E.; Ganley, Jeff T.; Maly, Joseph R.; Jurisson, Karl

2000-11-01

Despite growing international interest in small satellites, high dedicated expendable launch vehicle costs and the lack of secondary launch opportunities continue to hinder the full exploitation of small satellite technology. In the United States, the Department of Defense (DoD), NASA, other government agencies, commercial companies, and many universities use small satellites to perform space experiments, demonstrate new technology, and test operational prototype hardware. In addition, the DoD continues to study the role of small satellites in fulfilling operational mission requirements. However, the US lacks sufficient small satellite launch capacity. Furthermore, US government agencies are restricted to the use of US launch vehicles, which eliminates many affordable launch opportunities. In an effort to increase the number of space experiments that can be flown with a small, fixed budget, the DoD Space Test Program (STP) has teamed with the Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS) to develop a low-cost solution for the small satellite launch program. Our solution, which can be implemented on both Boeing and Lockheed-Martin Evolved Expendable Launch Vehicle-Medium (EELV-M) boosters, is called the EELV Secondary Payload Adaptor (ESPA). ESPA will increase the number of launch opportunities for 180kg-class (or smaller) satellites at prices highly competitive with other secondary launch services worldwide.

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.

Mineral phases and metals in baghouse dust from secondary aluminum production

Science.gov (United States)

Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78...

Origins and Scaling of Hot-Electron Preheat in Ignition-Scale Direct-Drive Inertial Confinement Fusion Experiments.

Science.gov (United States)

Rosenberg, M J; Solodov, A A; Myatt, J F; Seka, W; Michel, P; Hohenberger, M; Short, R W; Epstein, R; Regan, S P; Campbell, E M; Chapman, T; Goyon, C; Ralph, J E; Barrios, M A; Moody, J D; Bates, J W

2018-02-02

Planar laser-plasma interaction (LPI) experiments at the National Ignition Facility (NIF) have allowed access for the first time to regimes of electron density scale length (∼500 to 700  μm), electron temperature (∼3 to 5 keV), and laser intensity (6 to 16×10^{14}  W/cm^{2}) that are relevant to direct-drive inertial confinement fusion ignition. Unlike in shorter-scale-length plasmas on OMEGA, scattered-light data on the NIF show that the near-quarter-critical LPI physics is dominated by stimulated Raman scattering (SRS) rather than by two-plasmon decay (TPD). This difference in regime is explained based on absolute SRS and TPD threshold considerations. SRS sidescatter tangential to density contours and other SRS mechanisms are observed. The fraction of laser energy converted to hot electrons is ∼0.7% to 2.9%, consistent with observed levels of SRS. The intensity threshold for hot-electron production is assessed, and the use of a Si ablator slightly increases this threshold from ∼4×10^{14} to ∼6×10^{14}  W/cm^{2}. These results have significant implications for mitigation of LPI hot-electron preheat in direct-drive ignition designs.

Spatial assessment on ambient air quality status: a case study in ...

African Journals Online (AJOL)

Klang as the center of economic and industrial zone in Malaysia has been exposed to poor air quality condition over the years. This study was conducted to evaluate the spatial variation pattern of air quality status in Klang, Selangor by using a four years (2010-2013) secondary database from the Malaysian Department of ...

System approach for evaluation of air pollution toxic compounds in the 30-km area of nuclear power plants

International Nuclear Information System (INIS)

Shevtsova, O.V.; Zhigunova, L.N.; Makovskaya, N.A.; Pavlovich, E.L.

2012-01-01

The article shows the importance of a systematic approach to address environmental problems that arise during the construction of nuclear power plants, and identified the need to consider the transformation and biotransformation of primary pollutants and monitoring secondary pollutants. The basic pathways of pollutants in the air a 30-km zone of nuclear power plants established. The content of primary and secondary air pollutants identified. The evaluation of general toxic risk from primary pollutant and the calculation of the carcinogenic risk of secondary pollutants entering the body by inhalation are carried out. (authors)

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-09-01

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

Determination of the air attenuation and electronic loss for the free air concentric cylinders ionization chamber

International Nuclear Information System (INIS)

Oliveira, Hebert Pinto Silveira de

2010-01-01

Along the latest years, the LNMRI has been proceeding a continuous research work with a concentric cylinders type free air ionizing chamber (VICTOREEN, model 481), aiming to establish it as a new national standard, and, as a consequence, replace the worldwide accepted secondary standard, calibrated by PTB. Taking into account that the absolute determination of kerma in air with a free air ionizing chamber implies the acquirement of a number of correction factors. The main objective of the present work comprises the determination of the two factors, specifically, electronic loss (k e ) and air attenuation (k a ). The correction factors were obtained through mammography qualities reference spectrum, using Monte Carlo simulation method. The Penelope code was used in the simulation procedures. Simulations took place in two stages, the acquirement of specters related to the qualities of interest (mammography) with the x ray tube (Pantak, model HF160 e Panalytical, model XRF window), and the free-air ionization chamber. The data were compared to those related to the BIPM chamber, to electronic loss were not detected. The comparison between air attenuation factors was obtained data bellow 0.13%. (author)

Filter for underground mining for suction of preferably full cut and part cut machines, to be provided with preheated air, to avoid dropping below the dew point

Energy Technology Data Exchange (ETDEWEB)

Hoelter, H.

1976-10-28

Particularly when cutting hard rock, the cutting room to be provided with suction is wetted with water from nozzles, which, when sucking out air containing dust with high humidity leads to encrustation in the filter cloth. In order to avoid this, it is proposed that the air should be heated, using heat from the motor driving the ventilator, so that one avoids dropping below the dew point in the filter.

Multi-objective optimization and exergoeconomic analysis of a combined cooling, heating and power based compressed air energy storage system

International Nuclear Information System (INIS)

Yao, Erren; Wang, Huanran; Wang, Ligang; Xi, Guang; Maréchal, François

2017-01-01

Highlights: • A novel tri-generation based compressed air energy storage system. • Trade-off between efficiency and cost to highlight the best compromise solution. • Components with largest irreversibility and potential improvements highlighted. - Abstract: Compressed air energy storage technologies can improve the supply capacity and stability of the electricity grid, particularly when fluctuating renewable energies are massively connected. While incorporating the combined cooling, heating and power systems into compressed air energy storage could achieve stable operation as well as efficient energy utilization. In this paper, a novel combined cooling, heating and power based compressed air energy storage system is proposed. The system combines a gas engine, supplemental heat exchangers and an ammonia-water absorption refrigeration system. The design trade-off between the thermodynamic and economic objectives, i.e., the overall exergy efficiency and the total specific cost of product, is investigated by an evolutionary multi-objective algorithm for the proposed combined system. It is found that, with an increase in the exergy efficiency, the total product unit cost is less affected in the beginning, while rises substantially afterwards. The best trade-off solution is selected with an overall exergy efficiency of 53.04% and a total product unit cost of 20.54 cent/kWh, respectively. The variation of decision variables with the exergy efficiency indicates that the compressor, turbine and heat exchanger preheating the inlet air of turbine are the key equipment to cost-effectively pursuit a higher exergy efficiency. It is also revealed by an exergoeconomic analysis that, for the best trade-off solution, the investment costs of the compressor and the two heat exchangers recovering compression heat and heating up compressed air for expansion should be reduced (particularly the latter), while the thermodynamic performance of the gas engine need to be improved

Performance and emission study of preheated Jatropha oil on medium capacity diesel engine

Energy Technology Data Exchange (ETDEWEB)

Chauhan, Bhupendra Singh; Du Jun, Yong; Lee, Kum Bae [Division of Automobile and Mechanical Engineering, Kongju National University (Korea); Kumar, Naveen [Department of Mechanical Engineering, Delhi Technological University, Bawana Road, Delhi 42 (India)

2010-06-15

Diesel engines have proved their utility in transport, agriculture and power sector. Environmental norms and scared fossil fuel have attracted the attention to switch the energy demand to alternative energy source. Oil derived from Jatropha curcas plant has been considered as a sustainable substitute to diesel fuel. However, use of straight vegetable oil has encountered problem due to its high viscosity. The aim of present work is to reduce the viscosity of oil by heating from exhaust gases before fed to the engine, the study of effects of FIT (fuel inlet temperature) on engine performance and emissions using a dual fuel engine test rig with an appropriately designed shell and tube heat exchanger (with exhaust bypass arrangement). Heat exchanger was operated in such a way that it could give desired FIT. Results show that BTE (brake thermal efficiency) of engine was lower and BSEC (brake specific energy consumption) was higher when the engine was fueled with Jatropha oil as compared to diesel fuel. Increase in fuel inlet temperature resulted in increase of BTE and reduction in BSEC. Emissions of NO{sub x} from Jatropha oil during the experimental range were lower than diesel fuel and it increases with increase in FIT. CO (carbon monoxide), HC (hydrocarbon), CO{sub 2} (carbon dioxide) emissions from Jatropha oil were found higher than diesel fuel. However, with increase in FIT, a downward trend was observed. Thus, by using heat exchanger preheated Jatropha oil can be a good substitute fuel for diesel engine in the near future. Optimal fuel inlet temperature was found to be 80 C considering the BTE, BSEC and gaseous emissions. (author)

Assessment of children environmental exposure to secondary emission of nickel, lead and copper

Directory of Open Access Journals (Sweden)

Jerzy Kwapuliński

2012-12-01

Full Text Available Introduction: Total rating impact of particulate matter in ground air layer recently takes on particular significance in evaluation of health risk. Indeed particulate matter is of interest to many research centres, however in so far PM related works the probability of adverse health impacts were not taken into account triggered with impact of additional presence of particulate matter from secondary dusting. The aim of the work: The work target was determination of secondary emission of Cu, Ni and Pb measured in streets with high traffic volume in many towns of Silesia Voivodeship. Materials and methods: Dust collected from the distance of about 200 m from busy roads in Upper Silesia cities was analyzed by the method of plasma spectrophotometry. The phenomenon of secondary dusting was defined by few coefficients of: secondary emission, enrichment, contamination and parameter of extra mass of a given metal in widespread air pollution. Results: It was concluded that absorbed dose of Cu and Pb changes depends on the area under study and decreases along with child’s age. Decrease of absorbed age depending doses is explained, so far, by significant increase of body mass in comparison to anatomically conditioned size of respiratory system.Also health risk estimated in relation to children residing in selected areas is diversified.. And it also decreases along with the children growing older. It appears, however, that health risk is determined by the volume of secondary PM emission and to children mostly threatened with Ni belong those who are particularly exposed to secondary emission of this metal. The secondary dusting is particularly dangerous for respiratory system and plays more important role than averaged content of this chemical in the environment.

Hybrid solar central receiver for combined cycle power plant

Science.gov (United States)

Bharathan, Desikan; Bohn, Mark S.; Williams, Thomas A.

1995-01-01

A hybrid combined cycle power plant including a solar central receiver for receiving solar radiation and converting it to thermal energy. The power plant includes a molten salt heat transfer medium for transferring the thermal energy to an air heater. The air heater uses the thermal energy to preheat the air from the compressor of the gas cycle. The exhaust gases from the gas cycle are directed to a steam turbine for additional energy production.

Autologous Blood Pleurodesis In Patients With Persistent Air Leaks

Directory of Open Access Journals (Sweden)

Agkajanzadeh M

2003-10-01

Full Text Available Persistent air leaks occur after Spontaneous pneumothorax both primary and secondary, and after lungs trauma and lung surgeries are sever problems encountered chest surgeons with. Persistent air leak causes longer patients hospitalization."nMaterials and Methods: We used autologous blood pleurodesis in patients with persistent air leak for 30patients with more than 8 days air leaks, during a three years period 1377-1380 (1999-2002."nResults: The patients had 19 years up to 70 years old. Eight patients had thoracotomy and lobectomy and /or segmentectomies 6 with primary pneumothorax, 10 with secondary pneumothorax, and four with penetrated or blunt thoracic traumas. Blood was obtained from femoral or brachial veins and 70-150 mis. Injected in chest tubes. Chest bottle was first lied 80cm higher than body levels. After 24 hours repositioned in normal levels, and patients were supervised. Via chest tube we injected blood 70-100ml.for young patients, and 100-150 ml for older patients into intra pleural space. There were no clamped chest tubes. There were no pain, respiratory distress, fever, or cough in pleurodesized patients. The only patient's complaint was local pain in femoral vein or brachial vein because blood sampling and blood obtaining, although there was no local visible complication as hematoma or bleeding. After 48 hours in 24 patients air leak ceased. In six patients because persistent air leak autologous blood pleurodesis repeated, two patients after 48hours"nair leak ceased, remaining four patients underwent for thoracotomies, success rate"nwas 86.6%."nConclusion: According above success rate we suggest autologous blood pleurodesis in patients with persistent air leak is a reliable, effective, and no complicated procedure for persistent air leaks.

Parameter optimization through performance analysis of model based control of a batch heat treatment furnace with low NO x radiant tube burner

International Nuclear Information System (INIS)

Tiwari, Manish Kumar; Mukhopadhyay, Achintya; Sanyal, Dipankar

2005-01-01

A model based control structure for heat treating a 0.5% C steel slab in a batch furnace with low NO x radiant tube burner is designed and tested for performance to yield optimal parameter values using the model developed in the companion paper. Combustion is considered in a highly preheated and product gas diluted mode. Controlled combustion with a proposed arrangement for preheating and diluting the air by recirculating the exhaust gas that can be retrofitted with an existing burner yields satisfactory performance and emission characteristics. Finally, the effect of variable property considerations are presented and critically analyzed

Summary and evaluation of the conceptual design study of a potential early commercial MHD power plant (CSPEC)

Science.gov (United States)

Staiger, P. J.; Penko, P. F.

1982-01-01

The conceptual design study of a potential early commercial MHD power plant (CSPEC) is described and the results are summarized. Each of two contractors did a conceptual design of an approximtely 1000 MWe open-cycle MHD/steam plant with oxygen enriched combustion air preheated to an intermediate temperatue in a metallic heat exchanger. The contractors were close in their overall plant efficiency estimates but differed in their capital cost and cost of electricity estimates, primarily because of differences in balance-of-plant material, contingency, and operating and maintenance cost estimates. One contractor concluded that its MHD plant design compared favorably in cost of electricity with conventional coal-fired steam plants. The other contractor is making such a comparison as part of a follow-on study. Each contractor did a preliminary investigation of part-load performance and plant availability. The results of NASA studies investigating the effect of plant size and oxidizer preheat temperature on the performance of CSPEC-type MHD plants are also described. The efficiency of a 1000 MWe plant is about three points higher than of a 200 MWe plant. Preheating to 1600 F gives an efficiency about one and one-half points higher than preheating to 800 F for all plant sizes. For each plant size and preheat temperature there is an oxidizer enrichment level and MHD generator length that gives the highest plant efficiency.

Influence of the Steam Addition on Premixed Methane Air Combustion at Atmospheric Pressure

Directory of Open Access Journals (Sweden)

Mao Li

2017-07-01

Full Text Available Steam-diluted combustion in gas turbine systems is an effective approach to control pollutant emissions and improve the gas turbine efficiency. The primary purpose of the present research is to analyze the influence of steam dilution on the combustion stability, flame structures, and CO emissions of a swirl-stabilized gas turbine model combustor under atmospheric pressure conditions. The premixed methane/air/steam flame was investigated with three preheating temperatures (384 K/434 K/484 K and the equivalence ratio was varied from stoichiometric conditions to the flammability limits where the flame was physically blown out from the combustor. In order to represent the steam dilution intensity, the steam fraction Ω defined as the steam to air mass flow rate ratio was used in this work. Exhaust gases were sampled with a water-cooled emission probe which was mounted at the combustor exit. A 120 mm length quartz liner was used which enabled the flame visualization and optical measurement. Time-averaged CH chemiluminescence imaging was conducted to characterize the flame location and it was further analyzed with the inverse Abel transform method. Chemical kinetics calculation was conducted to support and analyze the experimental results. It was found that the LBO (lean blowout limits were increased with steam fraction. CH chemiluminescence imaging showed that with a high steam fraction, the flame length was elongated, but the flame structure was not altered. CO emissions were mapped as a function of the steam fraction, inlet air temperature, and equivalence ratios. Stable combustion with low CO emission can be achieved with an appropriate steam fraction operation range.

Secondary emissions during fiber laser cutting of nuclear material

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-15

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

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

KAUST Repository

Lee, Da Hoon

2017-08-05

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

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

KAUST Repository

Lee, Da Hoon; Kang, Sun Kil; Pak, Yusin; Lim, Namsoo; Lee, Ryeri; Kumaresan, Yogeenth; Lee, Sungeun; Lee, Chaedeok; Ham, Moon-Ho; Jung, Gun Young

2017-01-01

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

OUT Success Stories: Transpired Solar Collectors

International Nuclear Information System (INIS)

Clyne, R.

2000-01-01

Transpired solar collectors are a reliable, low-cost technology for preheating building ventilation air. With simple payback periods ranging from 3 to 12 years and an estimated 30-year life span, transpired collector systems offer building owners substantial cost savings

Preparation and characterization of ZnO transparent semiconductor thin films by sol-gel method

International Nuclear Information System (INIS)

Tsay, Chien-Yie; Fan, Kai-Shiung; Chen, Sih-Han; Tsai, Chia-Hao

2010-01-01

Transparent semiconductor thin films of zinc oxide (ZnO) were deposited onto alkali-free glass substrates by the sol-gel method and spin-coating technique. In this study, authors investigate the influence of the heating rate of the preheating process (4 or 10 o C/min) on the crystallization, surface morphology, and optical properties of sol-gel derived ZnO thin films. The ZnO sol was synthesized by dissolving zinc acetate dehydrate in ethanol, and then adding monoethanolamine. The as-coated films were preheated at 300 o C for 10 min and annealed at 500 o C for 1 h in air ambiance. Experimental results indicate that the heating rate of the preheating process strongly affected the surface morphology and transparency of ZnO thin film. Specifically, a heating rate of 10 o C/min for the preheating process produces a preferred orientation along the (0 0 2) plane and a high transmittance of 92% at a wavelength of 550 nm. Furthermore, this study reports the fabrication of thin-film transistors (TFTs) with a transparent ZnO active channel layer and evaluates their electrical performance.

Measurements of secondary emissions from plasma arc and laser cutting in standard experiments

International Nuclear Information System (INIS)

Pilot, G.; Noel, J.P.; Leautier, R.; Steiner, H.; Tarroni, G.; Waldie, B.

1992-01-01

As part of an inter-facility comparison of secondary emissions from plasma arc and laser-cutting techniques, standard cutting tests have been done by plasma arc underwater and in air, and by laser beam in air. The same team was commissioned to measure the secondary emissions (solid and gaseous) in each contractor's facility with the same measuring rig. 20 mm and 40 mm thick, grade 304 stainless-steel plates were cut by plasma-torch in three different facilities: Heriot Watt University of Edinburgh, Institut fuer Werkstoffkunde of Universitaet Hannover and CEA/CEN Cadarache. 10 mm and in some cases 20 mm thick, grade 304, stainless-steel plates were cut by laser beam in five different facilities: CEA-CEN Fontenay, CEA-CEN Saclay, Institut fuer Werkstoffkunde of Universitaet Hannover and ENEA/Frascati. The results obtained in the standard experiments are rather similar, and the differences that appear can be explained by the various scales of the involved facilities (semi-industrial and laboratory) and by some particularities in the cutting parameters (an additional secondary gas flow of oxygen in plasma cutting at Universitaet Hannover, for example)

Measurements of secondary emissions from plasma arc and laser cutting in standard experiments

International Nuclear Information System (INIS)

Pilot, G.; Noel, M.; Leautier, R.; Steiner, H.; Tarroni, G.; Waldie, B.

1990-01-01

As part of an inter-facility comparison of secondary emissions from plasma-arc and laser cutting techniques, standard cutting tests have been done by plasma arc underwater and in air and laser beam in air. The same team, CEA/DPT/SPIN, was commissioned to measure the secondary emissions (solid and gaseous) in each contractor's facility with the same measuring rig. 20 mm and 40 mm thick grade 304 stainless steel plates were cut by plasma-torch in three different facilities: Heriot Watt University of Edinburgh, Institute fuer Werkstoffkunde of Hannover and CEA/CEN Cadarache. 10 mm and sometimes 20 mm thick grade 304 stainless steel plates were cut by laser beam in four different facilities: CEA/CEN Fontenay, CEA/CEN Saclay, Institute fuer Werkstoffkunde of Hannover and ENEA/FRASCATI. The results obtained in the standard experiments are rather similar, the differences that appear can be explained by the various scales of the facilities (semi-industrial and laboratory scale) and by some particularity in the cutting parameters (additional secondary gas flow of oxygen in plasma cutting at Hannover for example). Some supplementary experiments show the importance of some cutting parameters. (author)

Magnetohydrodynamic generation method

International Nuclear Information System (INIS)

Masai, Tadahisa; Ishibashi, Eiichi; Kojima, Akihiro.

1967-01-01

The present invention relates to a magneto-hydrodynamic generation method which increases the conductivity of active gas and the generated energy. In the conventional method of open-cycle magnetohydrodynamic generation, the working fluid does not possess a favorable electric conductivity since the collision cross section is large when the combustion is carried out in a condition of excess oxygen. Furthermore, combustion under a condition of oxygen shortage is uncapable of completely converting the generated energy. The air preheater or boiler is not sufficient to collect the waste gas resulting in damage and other economic disadvantages. In the present invention, the combustion gas caused by excess fuel in the combuster is supplied to the generator as the working gas, to which air or fully oxidized air is added to be reheated. While incomplete gas used for heat collection is not adequate, the unburned damage may be eliminated by combusting again and increasing the gas temperature and heat collection rate. Furthermore, a diffuser is mounted at the rear side of the generator to decrease the gas combustion rate. Thus, even when directly absorbing the preheated fully oxidized air or the ordinary air, the boiler is free from damage caused by combustion delay or impulsive force. (M. Ishida)

Solar energy system performance evaluation report for Solaron-Duffield, Duffield, Virginia

Science.gov (United States)

1980-07-01

The Solaron Duffield Solar Energy System was designed to provide 51 percent of the space heating, and 49 percent of the domestic hot water (DHW) to a two story 1940 square foot area residence using air as the transport medium. The system consists of a 429 square foot collector array, a 265 cubic foot rock thermal storage bin, heat exchangers, an 80 gallon DHW preheat tank, pumps, blowers, controls, air ducting and associated plumbing. A air-to-liquid heat pump coupled with a 1,000gallon water storage tank provides for auxiliary space heating and can also be used for space cooling. A 52 gallon electric DHW tank using the solar preheated water provides domestic hot water to the residence. The solar system, which became operational July 1979, has the following modes of operation: First Stage: (1) collector to storage and DHW; (2)collector to space heating; (3) storage to load. Second Stage: (4) heat pump auxiliary direct; (5) auxiliary heat from heat pump storage. Third Stage: (6) electrical resistance (strip) heat.

Heat exchanger operation in the externally heated air valve engine with separated settling chambers

International Nuclear Information System (INIS)

Kazimierski, Zbyszko; Wojewoda, Jerzy

2014-01-01

The crucial role in the externally heated air valve engine is played by its heat exchangers which work in a closed cycle. These are: a heater and a cooler and they are subject to a numerical analysis in the paper. Both of them are equipped with fixed volumes that are separate settling chambers causing that heat exchangers behave as almost stationary recuperators and analysis of the stationary behaviour is the main goal of the paper. Power and efficiency of the engine must be not lower than their averaged values for the same engine working in unsteady conditions. The results of calculations confirm such a statement. The pressure drop in the exchanger is another natural phenomenon presented. It has been overcome by use of additional blowers and the use of them is an additional focus of the presented analysis. A separation of settling chambers and additional blowers is a novelty in the paper. There is also a pre-heater applied in the engine which does not differ from well-known heat exchangers met in energy generation devices. The main objective of the paper is to find the behaviour of the engine model under stationary conditions of the heat exchangers and compare it with the non-stationary ones. - Highlights: • Externally heated air engine combined with forced working gas flow (supercharging). • Separate settling chambers allow for achieving stable and constant heat exchange parameters. • Pressure drop in heat exchangers overcome by additional blowers. • Reciprocating piston air engine, cam governing system, standard lubrication for externally heated engine. • Different fuels: oil, coal, gas, biomass also solar or nuclear energy

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

Directory of Open Access Journals (Sweden)

S. M. Al-Salem

2010-01-01

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

Process and apparatus for decontaminating air

International Nuclear Information System (INIS)

Reynolds, W.D.

1993-01-01

An apparatus for irradiating a contaminated air stream emanating from contaminated sources which contain mixtures of one or more volatile toxic and hazardous organic solvents or petroleum product vapors with ultraviolet wave energy below 200 nm is described comprising: a first means for passing the contaminated air stream via a tube into an enclosed empty air flow duct to allow free flow of said contaminated air stream; a second means for introducing a secondary fresh air stream into an inlet of said first means to dilute and maintain the contaminated air stream at a predetermined concentration level; a means for measuring a flow rate of said contaminated air stream; said air duct containing at least a first and second residence chambers separated by a wall divider; said divider containing at least one opening in which is mounted at least one centrally located ultraviolet wave energy source extending into said air stream to allow said contaminated air stream to pass around and in close contact with said wave energy source, wherein said contaminated air stream is irradiated by said wave energy source; an analyzer means for conducting on-line real time analysis of said diluted contaminated air stream in said first residence chamber, said analyzer means being capable of analyzing any residual contaminated mixtures in an effluent air stream from said second residence chamber; whereby said ultraviolet wave energy source functions to generate oxygen atom free radicals, other free radicals, ions, and ozone to react with the contaminated air strewn to produce unwanted acid gases, and wherein said effluent air stream containing the unwanted acid gases, being passed from said second residence chamber, can be disposed of in any manner known to the art

Dictionary of cement. Manufacture and technology. German-English. English-German. 2. Rev. and enlarged Ed. Zementwoerterbuch. Herstellung und Technologie. Deutsch-Englisch. Englisch-Deutsch

Energy Technology Data Exchange (ETDEWEB)

Van Amerongen, C

1986-01-01

This book deals with the following fields: cement chemistry; chemical and physical testing; quarrying (drilling, blasting, excavating and loading machinery, haulage vehicles); crushing and grinding; sampling; materials handling; blending, homogenizing, storage (blending beds, silos); kilns, preheaters, precalciners; firing technology (fuels, burners); refractories; clinker coolers; air separators (classifiers); dust collecting equipment (filters, electrostatic precipitators); air pollution and noise control; bulk handling installations; sack packing machines; packaging, palletizing, dispatch.

Secondary damages to forests caused by industrial exhausts

Energy Technology Data Exchange (ETDEWEB)

Donaubauer, E

1966-01-01

Acute and chronic damages of diverse origins modify the susceptibility of trees to certain insects and infectious diseases. Especially in connection with air pollution damages, it must be pointed out that such predisposition may occur long before any symptoms become visible or before any growth losses can be measured. In many instances, it is very difficult to evaluate these secondary damages. Very extensive regional comparisons are necessary in order to obtain evidence of damage. Increased occurrence of parasites and/or disease within the emission area must be compared with the frequency and intensity of occurrence outside of said area; this may then serve as circumstantial proof of a demonstrated secondary damage. Examples of these kinds of effects caused by parasitic fungi and insects are discussed in detail. 27 references.

Modified Thermodynamic Equilibrium Model for Biomass Gasification: A Study of the Influence of Operating Conditions

DEFF Research Database (Denmark)

Puig Arnavat, Maria; Bruno, Juan Carlos; Coronas, Alberto

2012-01-01

data from different authors for downdraft, fluidized-bed gasifiers and different biomasses, showing good agreement between reported data and modeled values. In addition, it has been used to evaluate the influence of different operating parameters [equivalence ratio (ER), air preheating, steam injection...

Socio-economic considerations of cleaning Greater Vancouver's air

International Nuclear Information System (INIS)

2005-08-01

Socio-economic considerations of better air quality on the Greater Vancouver population and economy were discussed. The purpose of the study was to provide socio-economic information to staff and stakeholders of the Greater Vancouver Regional District (GVRD) who are participating in an Air Quality Management Plan (AQMP) development process and the Sustainable Region Initiative (SRI) process. The study incorporated the following methodologies: identification and review of Canadian, American, and European quantitative socio-economic, cost-benefit, cost effectiveness, competitiveness and health analyses of changes in air quality and measures to improve air quality; interviews with industry representatives in Greater Vancouver on competitiveness impacts of air quality changes and ways to improve air quality; and a qualitative analysis and discussion of secondary quantitative information that identifies and evaluates socio-economic impacts arising from changes in Greater Vancouver air quality. The study concluded that for the Greater Vancouver area, the qualitative analysis of an improvement in Greater Vancouver air quality shows positive socio-economic outcomes, as high positive economic efficiency impacts are expected along with good social quality of life impacts. 149 refs., 30 tabs., 6 appendices

Studies of MHD generator performance with oxygen enriched coal combustion

Science.gov (United States)

Wormhoudt, J.; Yousefian, V.; Kolb, C. E.; Martinez-Sanchez, M.

1980-07-01

This paper presents calculations made using the Aerodyne PACKAGE (Plasma Analysis, Chemical Kinetics, and Generator Efficiency) computer code which bear on two questions which arise in connection with choices between oxygen enrichment and air preheating to attain the high combustion temperatures needed for open-cycle, coal-fired MHD power generation. The first question is which method produces the highest enthalpy extraction per unit channel length. The second is, in test facilities intended to study tradeoffs between oxygen enrichment and preheated air, can good generator performance be obtained from the same physical channel for different combustor compositions. The answer to the first question is found to depend on what combustor conditions are taken to be comparable. As for the second question, it is found that operation with channel input from off-design combustor conditions can cause serious problems, which can be partially alleviated by changing the channel load factors.

Distilling carbonaceous material

Energy Technology Data Exchange (ETDEWEB)

Karrick, L C

1926-11-02

Coal, shale and the like are distilled in a current of superheated steam which is passed into a retort at about midway between its ends a further supply being if necessary introduced at the bottom to generate water-gas, and the coke being dry quenched in a hopper below the retort. Combustion products may also be introduced and the temperature may be varied from 950 to 1725/sup 0/F, oil, gas, resin and a residual coke having good adsorbent value, being obtained. The charge from hoppers and auxiliary hoppers is fed to retorts situated between gas and steam preheaters, the rate of downward movement being controlled by discharge rollers having arms, counterweighted rocking arms allowing the residue to be fed downwards into hoppers. Steam from a pipe is superheated in horizontal passages, and admitted through ports into the retort. Preheated fuel gas is burnt in combustion flues and passes down through vertical flues, across horizontal flues and up flues adjacent the retorts, from which by ports and flues it passes down a chamber having an air or gas preheater each having two independent systems, one discharging into the combustion chamber beneath it and the other into an adjacent chamber. Air or gas enters by pipes and after being heated in pipes is fed by ports to the chamber. The volatiles pass off through outlets leading to a main air cooled condenser and a water-cooled condenser delivering to a separating tank connecting with pipes for quenching the residues and with pipes to preheat the charge in the hoppers and maintain a gas barrier the rein. Superheated steam may also be admitted through ports to generate water-gas and increase the total volume of gases and combustion products may be introduced through ports. The upper part of the retort is made of cast iron, the high temperature parts of silica or carborundum brick, and the lower part of chrome iron or other metal.

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

International Nuclear Information System (INIS)

Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

2016-01-01

Highlights: • An integrated thermal management system is proposed for electric vehicle. • The parallel branch of battery chiller can supply additional cooling capacity. • Heat pipe performance on preheating mode is better than that on cooling mode. • Heat pipe heat exchanger is a feasible choice for battery thermal management. - Abstract: An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode.

A new way of air shower detection: measuring the properties of cosmic rays with LOFAR

NARCIS (Netherlands)

Nelles, A.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Rachen, J. P.; Schellart, P.; Scholten, O.; ter Veen, S.; Thoudam, S.; Trinh, T.N.G.

2015-01-01

High-energy cosmic rays impinging onto the atmosphere of the Earth initiate cascades of secondary particles: extensive air showers. Many of the particles in a shower are electrons and positrons. During the development of the air shower and by interacting with the geomagnetic field, the

Status of air kerma and absorbed dose standards in India

International Nuclear Information System (INIS)

Vijayam, M.; Ramanathan, G.; Patki, V.S.; Soman, A.T.; Shigwan, J.B.; Vinatha, S.P.; Jadhavgaonkar, P.S.; Kadam, V.D.; Shaha, V.V.; Abani, M.C.

2002-01-01

Full text: The Radiation Safety Systems Division of Bhabha Atomic Research Centre, India maintains Primary and Secondary Standards of various parameters of radiation measurements and provides calibration services to various users of radiation in the country. This is an apex laboratory in India and plays a pivotal role in ensuring accurate radiological measurements. The laboratory coordinates national intercomparisons of radiation measurements to maintain their uniformity and traceability and is linked through various programmes with the other International organizations such as Bureau Internationale des Poids et Mesures (BIPM) Paris, International Atomic Energy Agency (IAEA) Vienna, Asia Pacific Metrology Programme (APMP) Taiwan. It is the recognized Regional Secondary Standards Dosimetry Laboratory (SSDL) of IAEA/WHO (World Health Organisation). This paper brings out the status of various primary and secondary standards for radiological measurements maintained at BARC. 1. Primary Exposure/Air-kerma standard at Co-60 energy (therapy level): The primary standard for exposure/ air-kerma measurements maintained at BARC is a graphite cavity chamber of volume 4.362 cc with an internal diameter of 1.8 cm, internal height of 1.78 cm and wall thickness of 704.3mg/cm 2 . Correction factors for the difference between electron stopping powers, photon mass energy absorption coefficients of air and graphite wall, correction for recombination, radiation field non-uniformity, stem scatter and polarity effect are applied and the maximum overall uncertainty in the realisation of exposure/air-kerma is around ±1%. This standard has been intercompared with IAEA and BIPM through transfer standard and the agreement in the results are better than ±1%. An intercomparison under the APMP programme is to be held during May, 2002. 2. Primary Exposure/Air-kerma standard at protection and brachytherapy level: A set of three spherical graphite-walled cavity chambers of different air

Secondary drive of an internal combustion engine for an air presser. Nebenantrieb einer Brennkraftmaschine fuer einen Luftpresser

Energy Technology Data Exchange (ETDEWEB)

Kubis, H.

1990-04-19

The invention concerns an air presser propelled by a gearwheel and designed as a piston compressor. The drive gearwheel on the air presser crankshaft meshes with a gearwheel on the camshaft of the internal combustion engine. In the case of these drives, a negative torque of the air presser results when the top dead centre of the air presser piston is reached. This is accompanied by an unpleasant noise. In addition, the driving torque of the camshaft often has negative fractions. If the negative torque of the air presser is superposed by small or negative torques of the camshaft in the re-expansion phase additionally to the air presser wheel there will be a backward acceleration of the camshaft gear which propagates as impact into the rest of the gear drive. The invention prevents the backward acceleration of the camshaft wheel and minimizes stroke momentum and noise in the mesh of the camshaft wheel.

77 FR 58076 - Revisions to the California State Implementation Plan, South Coast Air Quality Management District

Science.gov (United States)

2012-09-19

... the California State Implementation Plan, South Coast Air Quality Management District AGENCY... the South Coast Air Quality Management District (SCAQMD) portion of the California State... Quality Standards (NAAQS). The revisions to the primary and secondary Lead NAAQS were to provide increased...

Wave energy absorption by a floating air bag

DEFF Research Database (Denmark)

Kurniawan, Adi; Chaplin, John; Greaves, Deborah

2017-01-01

A floating air bag, ballasted in water, expands and contracts as it heaves under wave action. Connecting the bag to a secondary volume via a turbine transforms the bag into a device capable of generating useful energy from the waves. Small-scale measurements of the device reveal some interesting...

Infrared Signature Masking by Air Plasma Radiation

Science.gov (United States)

Kruger, Charles H.; Laux, C. O.

2001-01-01

This report summarizes the results obtained during a research program on the infrared radiation of air plasmas conducted in the High Temperature Gasdynamics Laboratory at Stanford University under the direction of Professor Charles H. Kruger, with Dr. Christophe O. Laux as Associate Investigator. The goal of this research was to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. To this end, spectral measurements and modeling were made of the radiation emitted between 2.4 and 5.5 micrometers by an atmospheric pressure air plasma in chemical and thermal equilibrium at a temperature of approximately 3000 K. The objective was to examine the spectral emission of air species including nitric oxide, atomic oxygen and nitrogen lines, molecular and atomic continua, as well as secondary species such as water vapor or carbon dioxide. The cold air stream injected in the plasma torch contained approximately 330 parts per million of CO2, which is the natural CO2 concentration in atmospheric air at room temperatures, and a small amount of water vapor with an estimated mole fraction of 3.8x10(exp -4).

Effects of N2 gas on preheated laminar LPG jet diffusion flame

International Nuclear Information System (INIS)

Mishra, D.P.; Kumar, P.

2010-01-01

This paper presents an experimental investigation of the inert gas effect on flame length, NO x and soot free length fraction (SFLF) in a laminar LPG diffusion flame. Besides this, flame radiant fraction and temperature are also measured to explain observed NO x emission and SFLF. The inert is added to both air and fuel stream at each base line condition by maintaining a constant mass flow rate in each stream. Results indicate that inert addition leads to a significant enhancement in flame length for air-diluted stream than fuel-diluted stream. However, the flame length is observed to reduce with increasing reactant temperature. It is also observed that the SFLF increases with addition of N 2 for fuel-diluted stream. In contrast, SFLF remains almost constant when N 2 is added to air stream. The decrease in fuel concentration and gas temperature caused by inert addition leads to reduction in soot volume fraction and hence enhances SFLF. Interestingly, the SFLF reduces with increasing reactant temperature, due to reduction in induction period of soot formation caused by enhanced flame temperature. Besides this, the reduction in NO x emission level with inert addition is also observed. For all the three cases, the air dilution proved to be much efficient in reducing NO x emission level as compared to fuel dilution. This can be attributed to the differences in reduced gas temperature and residence time between air and fuel-diluted streams. On the contrary, NO x emission level enhances significantly with increasing reactant temperature as a result of increase in thermal NO x through Zeldovich mechanism.

Performance of hybrid quad generation system consisting of solid oxide fuel cell system and absorption heat pump

DEFF Research Database (Denmark)

Cachorro, Irene Albacete; Daraban, Iulia Maria; Lainé, Guillaume

2013-01-01

. The heat pump is a heat driven system and is running with the heat recovered by a heat exchanger from the exhausted gases from SOFC. The working fluid pair is NH3-H2O and is driven in two evaporators which are working at two different pressures. Thus, the heat pump will operate at tree pressure level...... with natural gas. The natural gas is first converted to a mixture of H2 and CO which feed the anode after a preheating step. The cathode is supplied with preheated air and gives, as output, electrical energy. The anode output is the exhaust gas which represents the thermal energy reservoir for heating...

The performance of the INER improved free-air ionization chamber in the comparison of air kerma calibration coefficients for medium-energy X-rays

Energy Technology Data Exchange (ETDEWEB)

Lee, J.-H. E-mail: jhlee@iner.gov.tw; Kotler, L.H.; Bueermann, Ludwig; Hwang, W.-S.; Chiu, J.-H.; Wang, C.-F

2005-01-01

This paper describes modifications to an original design, correction factors and uncertainty evaluations for an improved free-air ionization chamber constructed at the Institute of Nuclear Energy Research (INER, Taiwan). In addition, a comparison of secondary standard air kerma calibration coefficients for 100-250 kV medium-energy X-rays was performed to verify the experimental accuracy and measurement consistency of the improved chamber. The comparison results showed a satisfactory agreement in the measurements which were within the combined expanded uncertainties (k=2)

Solar Space and Water Heating for Hospital --Charlottesville, Virginia

Science.gov (United States)

1982-01-01

Solar heating system described in an 86-page report consists of 88 single-glazed selectively-coated baseplate collector modules, hot-water coils in air ducts, domestic-hot-water preheat tank, 3,000 Gallon (11,350-1) concrete urethane-insulated storage tank and other components.

Interaction patterns of major air pollutants in Hong Kong territory

International Nuclear Information System (INIS)

Lu, W.Z.; Wang, X.K.

2004-01-01

Air pollution in a metropolitan city like Hong Kong is a major obstacle to improve air quality and living environment due to the high population density and the vehicle emission increases. The high air pollutant levels impose harm to the human health and impair the city image. The characteristic analysis of air pollutants is very important and necessary to pollutant monitoring, forecasting and controlling. In this study, the interaction patterns of principle air pollutants, e.g. nitrogen dioxide (NO 2 ), nitric oxide (NO), nitric oxides (NO x ) and ozone (O 3 ), a secondary pollutant, are investigated based on the measured database in four selected areas, which covers two urban types (i.e. residential area, mixed residential/commercial/industrial area) in Hong Kong, during the period of 1999-2001. The study involves analyzing the chemical and physical properties, the characteristics of air pollutants and the factors affecting such interactions using statistical method. The results reveal several routines in urban air pollutants' variations, interaction and trends from macro aspect

78 FR 20868 - Approval and Promulgation of Implementation Plans; Designation of Areas for Air Quality Planning...

Science.gov (United States)

2013-04-08

... chemical reactions from precursor gases (e.g., secondary particles). Secondary particles, such as sulfates, nitrates, and complex carbon compounds, are formed from reactions with oxides of sulfur (SO X ), oxides of... nonattainment new source review (nonattainment NSR) permit programs; provisions for air pollution modeling; and...

Turbulence production due to secondary vortex cutting in a turbine rotor

Science.gov (United States)

Binder, A.

1985-10-01

Measurements of the unsteady flow field near and within a turbine rotor were made by means of a Laser-2-Focus velocimeter. The testing was performed in a single-stage cold-air turbine at part-load and near-design conditions. Random unsteadiness and flow angle results indicate that the secondary vortices of the stator break down after being cut and deformed by the rotor blades. A quantitative comparison shows that some of the energy contained in these secondary vortices is thereby converted into turbulence energy in the front part of the rotor. An attempt is made to explain this turbulence energy production as caused by the vortex breakdown.

Chemical and isotopic composition of secondary organic aerosol generated by alpha-pinene ozonolysis

NARCIS (Netherlands)

Meusinger, Carl; Dusek, Ulrike; King, Stephanie M.; Holzinger, Rupert; Rosenorn, Thomas; Sperlich, Peter; Julien, Maxime; Remaud, Gerald S.; Bilde, Merete; Rockmann, Thomas; Johnson, Matthew S.

2017-01-01

Secondary organic aerosol (SOA) plays a central role in air pollution and climate. However, the description of the sources and mechanisms leading to SOA is elusive despite decades of research. While stable isotope analysis is increasingly used to constrain sources of ambient aerosol, in many cases

Assessment of socio-economic consequences of the Commission's thematic strategy for air pollution

International Nuclear Information System (INIS)

Bach, H.; Skou Andersen, M.; Illerup, J.B.

2006-01-01

The Commission has presented a thematic strategy on air pollution and has completed an Impact Assessment, which describes the costs and benefits for the member states. The thematic strategy is to result in a revised air quality directive as well as a revised NEC-directive that determines maximum emissions for a number of air pollution components, the so-called emission ceilings. The air pollution components include sulphur dioxide (SO 2 ), nitrogen oxide (NO X ), volatile organic compounds (NMVOC), ammonia (NH 3 ) and particulate matters (PM 2,5 ). The thematic strategy draws up targets for reductions of the Danish emissions for these components, which have to be met by 2020. These reductions will contribute to a lowering of PM 2,5 concentrations both in Denmark and in neighbouring countries. The concentration of PM 2,5 in the air includes both primary particles that come from emission of particles from e.g. incineration processes, and so-called secondary particles that are generated from emissions of NO X , SO 2 and NH 3 , and from releases from e.g. vegetation. A very large part of the secondary particles in the air in Denmark stems from emissions of these components in the rest of Europe. A very important condition for a reduction in the concentration of PM 2,5 in the air is thus a reduction of the emissions of these components in all of Europe. (au)

The effects of rice canopy on the air-soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers.

Science.gov (United States)

Wang, Yan; Wang, Shaorui; Luo, Chunling; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

2015-05-01

The rice canopy in paddy fields can influence the air-soil exchange of organic chemicals. We used paired passive air samplers to assess the exchange of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in a paddy field, South China. Levels of OCPs and light PAHs were generally higher under the canopy than above it. We found that the rice canopy can physically obstruct the evaporation of most OCPs and light PAHs, and can also act as a barrier to the gaseous deposition of p,p'-DDT and heavy PAHs. Paddy fields can behave as a secondary source of OCPs and light PAHs. The homolog patterns of these two types of chemical varied slightly between the air below and above the rice canopy, implying contributions of different sources. Paired passive air samplers can be used effectively to assess the in situ air-soil exchange of PAHs and OCPs in subtropical paddy fields. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of Sulfur from CaF2 Containing Desulfurization Slag Exhausted from Secondary Steelmaking Process by Oxidation

Science.gov (United States)

Hiraki, Takehito; Kobayashi, Junichi; Urushibata, Satomi; Matsubae, Kazuyo; Nagasaka, Tetsuya

2012-08-01

The oxidation behavior of sulfur in desulfurization slag generated from the secondary steelmaking process with air has been investigated in the temperature range of 973 K to 1373 K (700 °C to 1100 °C). Although a high removal rate of sulfur is not achieved at temperatures lower than 1273 K (1000 °C) because of the formation of CaSO4, most of the sulfur is rapidly removed from slag as SO2 gas in the 1273 K to 1373 K (700 °C to 1100 °C) range. This finding indicates that the desulfurization slag generated from the secondary steelmaking process can be reused as a desulfurized flux through air oxidation, making it possible to reduce significantly the amount of desulfurization slag for disposal.

Hybrid Automotive Engine Using Ethanol-Burning Miller Cycle

Science.gov (United States)

Weinstein, Leonard

2004-01-01

A proposed hybrid (internal-combustion/ electric) automotive engine system would include as its internal-combustion subsystem, a modified Miller-cycle engine with regenerative air preheating and with autoignition like that of a Diesel engine. The fuel would be ethanol and would be burned lean to ensure complete combustion. Although the proposed engine would have a relatively low power-to-weight ratio compared to most present engines, this would not be the problem encountered if this engine were used in a non-hybrid system since hybrid systems require significantly lower power and thus smaller engines than purely internal-combustion-engine-driven vehicles. The disadvantage would be offset by the advantages of high fuel efficiency, low emission of nitrogen oxides and particulate pollutants, and the fact that ethanol is a renewable fuel. The original Miller-cycle engine, named after its inventor, was patented in the 1940s and is the basis of engines used in some modern automobiles, but is not widely known. In somewhat oversimplified terms, the main difference between a Miller-cycle engine and a common (Otto-cycle) automobile engine is that the Miller-cycle engine has a longer expansion stroke while retaining the shorter compression stroke. This is accomplished by leaving the intake valve open for part of the compression stroke, whereas in the Otto cycle engine, the intake valve is kept closed during the entire compression stroke. This greater expansion ratio makes it possible to extract more energy from the combustion process without expending more energy for compression. The net result is greater efficiency. In the proposed engine, the regenerative preheating would be effected by running the intake air through a heat exchanger connected to the engine block. The regenerative preheating would offer two advantages: It would ensure reliable autoignition during operation at low ambient temperature and would help to cool the engine, thereby reducing the remainder of the

The Impact of Post Harvest Agricultural Crop Residue Fires on Volatile Organic Compounds and Formation of Secondary Air Pollutants in the N.W. Indo-Gangetic Plain

Science.gov (United States)

Sinha, V.; Chandra, P.; Kumar, V.; Sarkar, C.

2015-12-01

The N.W. Indo-Gangetic Plain (IGP) is an agriculturally and demographically important region of the world. Every year during the post harvest months of April-May and October-November, large scale open burning of wheat straw and paddy straw occurs in the region impairing the regional air quality and resulting in air pollution episodes. Here, using online in-situ measurements from the IISER Mohali Atmospheric Chemistry Facility (Sinha et al., Atmos Chem Phys, 2014), which is located at a regionally representative suburban site in the agricultural state of Punjab, India, we investigated the effects of this activity on gas phase chemistry. The online data pertaining to the pre harvest and post harvest paddy residue fires in 2012, 2013 and 2014 were analyzed to understand the effect of this anthropogenic activity on atmospheric chemistry and regional air quality with respect to health relevant VOCs such as benzenoids and isocyanic acid and trace gases such as ozone and carbon monoxide. These compounds showed marked increases (factor of 2-3 times higher) in their concentrations which correlated with the biomass combustion tracers such as acetonitrile. Emissions from the paddy residue fires did not result in significant enhancement of ambient ozone in 2012 but instead sustained hourly daytime ozone concentrations at ~ 50 ppb during the late post monsoon season, despite decreases in solar radiation and temperature. Results of such massive perturbations to ambient chemical composition, reactivity and formation of secondary pollutants and its implications for human health will be presented in this paper.

Air pollution

International Nuclear Information System (INIS)

Nelson, P.

2000-01-01

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 NO 2 and aldehydes. In addition, global effects of gaseous and particulate emissions to the atmosphere have received significant recent attention, concentrations of atmospheric CO 2 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

First Principles Investigation of Zinc-anode Dissolution in Zinc-air Batteries

DEFF Research Database (Denmark)

Siahrostami, Samira; Tripkovic, Vladimir; Lundgård, Keld Troen

2013-01-01

With surging interest in high energy density batteries, much attention has recently been devoted to metal-air batteries. The zinc-air battery has been known for more than hundred years and is commercially available as a primary battery, but recharging has remained elusive; in part because...... the fundamental mechanisms still remain to be fully understood. Here, we present a density functional theory investigation of the zinc dissolution (oxidation) on the anode side in the zinc-air battery. Two models are envisaged, the most stable (0001) surface and a kink surface. The kink model proves to be more....... The applied methodology provides new insight into computational modelling and design of secondary metal-air batteries....

Impact of primary and secondary air supply intensity in stove on emissions of size-segregated particulate matter and carbonaceous aerosols from apple tree wood burning

Science.gov (United States)

Sun, Jian; Shen, Zhenxing; Zhang, Leiming; Zhang, Qian; Lei, Yali; Cao, Junji; Huang, Yu; Liu, Suixin; Zheng, Chunli; Xu, Hongmei; Liu, Hongxia; Pan, Hua; Liu, Pingping; Zhang, Renjian

2018-04-01

In order to assess emission factors (EF) more accurately from household biomass burning, a series of laboratory-controlled apple tree wood burning tests were conducted to measure the EFs of size-segregated particulate matter (PM) and carbonaceous aerosols. The controlled burning experiments were conducted with designed primary air (PA) and secondary air (SA) supply intensity. An optimum value of 7 m3·h- 1 was found for SA, resulting the highest modified combustion efficiency (92.4 ± 2.5%) as well as the lowest EFs of PM2.5 (0.13 ± 0.01 g·MJ- 1), OC (0.04 ± 0.03 g·MJ- 1) and EC (0.03 ± 0.01 g·MJ- 1). SA values of 7 and 10 m3·h- 1 resulted the lowest EFs for all the different PM sizes. In a test with PA of 6 m3·h- 1 and SA of 7 m3·h- 1, very low EFs were observed for OC1 (8.2%), OC2 (11.2%) and especially OP (Pyrolyzed OC) (0%, not detected), indicating nearly complete combustion under this air supply condition. Besides SA, higher PA was proved to have positive effects on PM and carbonaceous fraction emission reduction. For example, with a fixed SA of 1.5 m3·h- 1, EFs of PM2.5 decreased from 0.64 to 0.27 g·MJ- 1 when PA increased from 6 to 15 m3·h- 1 (P < 0.05). Similar reductions were also observed in EFs of OC, EC and size segregated PM.

Installation Restoration Program Records Search for Nellis Air Force Base, Nevada.

Science.gov (United States)

1982-06-01

solution has caused a secondary o ypsiferous 20,000± Bird Spring Formation, Monte Cristo enlargement of joints and fractures. rocks, and Sultan...activities included air-to-air gunnery training and ground firing using rail- mounted targets. A large portion of the range is no longer active. The pistol...is a building rented from a trailer court operation in Beatty, Nevada, 120 miles north- west of Nellis AFB. Hazardous waste generation does not occur

Fiscal 2000 achievement report. Model project for international energy consumption efficiency improvement (Model project for improvement of boiler and turbine efficiency); 2000 nendo seika hokoku. Kokusai energy shohi koritsuka tou model jigyo (Boira tabin koritsu kojo model jigyo)

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-12-01

A project was implemented for Japan to transfer its energy conservation technologies for helping Indonesia conserve energy and reduce CO2 emissions, which occurred at Muara Karang Thermal Power Plant of an Indonesian power company named PT PJB. Items to be introduced are condenser tubes (material change from cupro-nickel to titanium), ball cleaning equipment, turbine gland seal improvement, air preheater improvement, thermal efficiency management system, and so forth. In this fiscal year, turbine gland seals and air preheater elements were manufactured, and the thermal efficiency management system was designed. As an dissemination activity, 10 engineers were invited to Japan from the Indonesian Ministry of Energy and Mineral Resources, PT PLN, and PT PJB. They attended a training program lasting approximately two weeks, which included study tours to the factories actually building the equipment to be introduced and field/classroom training/education on thermal efficiency management and others. The engineers actively performed their boiler improvement work back in Indonesia. (NEDO)

Clinical experience of intrapleural administration of fibrin glue for secondary pneumothorax with advanced lung cancer

International Nuclear Information System (INIS)

Nishino, Takeshi; Takizawa, Hiromitsu; Yoshida, Mitsuteru; Kawakami, Yukikiyo; Sakiyama, Shoji; Kondo, Kazuya

2014-01-01

Secondary pneumothorax with advanced lung cancer is an intractable and serious pathosis, which directly aggravates patients' Quality of Life (QOL) and prognosis. We first select the intrapleural administration of fibrin glue for secondary pneumothorax with advanced lung cancer. From April 2009 to May 2012, we encountered 5 patients who developed secondary pneumothorax during treatment for advanced lung cancer. Their average age was 60.8 years old, and 4 of them had squamous cell carcinoma, 1 had adenocarcinoma, and all had unresectable advanced lung cancer. In 4 of them, the point of air leakage could be detected by pleurography, and leakage could be stopped by the intrapleural administration of fibrin glue. All of them could receive chemotherapy or radiotherapy after treatment for secondary pneumothorax. The intrapleural administration of fibrin glue may be an effective and valid treatment for intractable secondary pneumothorax with advanced lung cancer. (author)

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

Science.gov (United States)

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

2017-04-01

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

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

International Nuclear Information System (INIS)

Siddhartha Bhatt, M.

2007-01-01

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 O 2 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 O 2 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 O 2 in the flue gas of 6.0% before the APH. At an O 2 in the flue gas (before APH) of 7.2%, a mild limitation on the unit capacity of around 2-3% is experienced. When O 2 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

Controlled air pyrolysis incinerator

International Nuclear Information System (INIS)

Dufrane, K.H.; Wilke, M.

1982-01-01

An advanced controlled air pyrolysis incinerator has been researched, developed and placed into commercial operation for both radioactive and other combustible wastes. Engineering efforts cocentrated on providing an incinerator which emitted a clean, easily treatable off-gas and which produced a minimum amount of secondary waste. Feed material is continuously fed by gravity into the system's pyrolysis chamber without sorting, shredding, or other such pretreatment. Metal objects, liquids such as oil and gasoline, or solid products such as resins, blocks of plastic, tire, animal carcasses, or compacted trash may be included along with normal processed waste. The temperature of the waste is very gradually increased in a reduced oxygen atmosphere. Volatile pyrolysis gases are produced, tar-like substances are cracked and the resulting product, a relatively uniform, easily burnable material, is introduced into the combustion chamber. Steady burning is thus accomplished under easily controlled excess air conditions with the off-gasthen passing through a simple dry clean-up system. Gas temperatures are then reduced by air dilution before passing through final HEPA filters. Both commercial and nuclear installations have been operated with the most recent application being the central incinerator to service West Germany's nuclear reactors

Air-freshener burns: a new paradigm in burns etiology?

Science.gov (United States)

Sarwar, Umran; Nicolaou, M; Khan, M S; Tiernan, E

2011-10-01

We report a rare case of burns following the use of automated air-fresheners. We present a case report with a brief overview of the literature relating to burns associated with air-fresheners. The mechanism and treatment of these types of injuries are also described. A 44 year-old female was admitted under the care of the burns team following burns secondary to an exploding air-freshener canister. The patient sustained burns to the face, thorax and arms resulting in a seven-day hospital admission. The burns were treated conservatively. To our knowledge this is one of the few documented cases of burns as a result of air-fresheners. As they become more ubiquitous, we anticipate the incidence of such cases to increase. As such, they pose a potential public health concern on a massive scale.

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

Science.gov (United States)

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

Flow characterization and dilution effects of N2 and CO2 on premixed CH4/air flames in a swirl-stabilized combustor

International Nuclear Information System (INIS)

Han Yue; Cai Guo-Biao; Wang Hai-Xing; Bruno Renou; Abdelkrim Boukhalfa

2014-01-01

Numerically-aided experimental studies are conducted on a swirl-stabilized combustor to investigate the dilution effects on flame stability, flame structure, and pollutant emissions of premixed CH 4 /air flames. Our goal is to provide a systematic assessment on combustion characteristics in diluted regimes for its application to environmentally-friendly approaches such as biogas combustion and exhaust-gas recirculation technology. Two main diluting species, N 2 and CO 2 , are tested at various dilution rates. The results obtained by means of optical diagnostics show that five main flame regimes can be observed for N 2 -diluted flames by changing excess air and dilution rate. CO 2 -diluted flames follow the same pattern evolution except that all the domains are shifted to lower excess air. Both N 2 and CO 2 dilution affect the lean blowout (LBO) limits negatively. This behavior can be counter-balanced by reactant preheating which is able to broaden the flammability domain of the diluted flames. Flame reactivity is degraded by increasing dilution rate. Meanwhile, flames are thickened in the presence of both diluting species. NO x emissions are significantly reduced with dilution and proved to be relevant to flame stability diagrams: slight augmentation in NO x emission profiles is related to transitional flame states where instability occurs. Although dilution results in increase in CO emissions at certain levels, optimal dilution rates can still be proposed to achieve an ideal compromise

Experimental Analysis and Model Validation of an Opaque Ventilated Facade

DEFF Research Database (Denmark)

López, F. Peci; Jensen, Rasmus Lund; Heiselberg, Per

2012-01-01

Natural ventilation is a convenient way of reducing energy consumption in buildings. In this study an experimental module of an opaque ventilated façade (OVF) was built and tested for assessing its potential of supplying free ventilation and air preheating for the building. A numerical model was ...

Straw Combustion in a Grate Furnace

DEFF Research Database (Denmark)

Lans, Robert Pieter Van Der

1998-01-01

Fixed-bed combustion of straw has been conducted in a 15 cm diameter and 137 cm long cylindrical reactor. Air, which could be preheated, was introduced through the bottom plate. The straw was ignited at the top with a radiation heater. After ignition, when a self-sustaining reaction front...

ZZ AIRFEWG, Gamma, Neutron Transport Calculation in Air Using FEWG1 Cross-Section

International Nuclear Information System (INIS)

1985-01-01

1 - Description of program or function: Format: ANISN; Number of groups: 37 neutron / 21 gamma-ray; Nuclides: air (79% N and 21% O); Origin: DLC-0031/FEWG1 cross sections (ENDF/B-IV). Weighting spectrum: 1/E. The AIRFEWG library has been generated by an ANISN multigroup calculation of gamma-ray, neutron, and secondary gamma-ray transport in infinite homogeneous air using DLC-0031/FEWG1 cross sections. 2 - Method of solution: The results were generated with a P3, ANISN run with a source in a single energy group. Thus, 58 such runs were required. For sources in the 37 neutron groups, both neutron and secondary gamma-ray fluence results were calculated. For gamma-ray sources only gamma-ray fluences were calculated

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.

Secondary Hypertension

Science.gov (United States)

Secondary hypertension Overview Secondary hypertension (secondary high blood pressure) is high blood pressure that's caused by another medical condition. Secondary hypertension can be caused by conditions that affect your kidneys, ...

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)

Nakanishi, C.; Silva, C.P.G. da.

1988-10-01

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) [pt

The effect of pre-heating and pre-irradiation with gamma-rays on thermal annealing in-bis-[n-benzoil-n-(o) tolylhydroxylaminate] cooper (II)

International Nuclear Information System (INIS)

Nakanishi, C.; Silva, C.P.G. da.

1990-02-01

The main purpose of this work was to make a contribution on 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 gama-rays on the retention and thermal annealing of bis [N-benzoyl-N-(o)tolylhydroxylaminate] copper (II) was investigated. The complex was synthesized and later characterized by means of: determination of the melting-point, elemental analysis, infra-red and visible range absortion spectrophotometry. The compound was heated and also irradiated with gamma-rays in order to verify the effect of thermolysis on the retention. It seems that heat and gamma-radiaition can produce deffects which will lower the susceptibility of the compound to thermal annealling. On the basis on the model envolving electronic species some explanation of ours results were made and a mechanism was proposed for the retention and thermal annealing assuming the capture of free electrons and also the existence of holes. (author) [pt

Increasing energy efficiency by in-situ oxygen measurement in combustion gas and optimized fuel-air-ratio control; Effizienzsteigerung durch in-situ Sauerstoffmessung im Verbrennungsgas

Energy Technology Data Exchange (ETDEWEB)

Boltz, Yvonne [Marathon Sensors Inc., West Chester, OH (United States); Winter, Karl-Michael [PROCESS-ELECTRONIC GmbH, Heiningen (Germany)

2012-04-15

High energy costs as well as the necessity to minimize exhaust emissions require a most efficient usage of fossil primary energy resources. In heat treating but also in power generation natural gas is mostly used. Efficient burner systems and preheating combustion air using recuperators or regenerators minimize exhaust losses to a high extent. Another well known but seldom used optimization method controls the excess oxygen percentage in the exhaust gas. Already partially in use in households and state-of-the-art in the combustion control of car engines this technique is still not widely used in industrial sized systems. For closed burners there are few sensor options available that can be integrated into the burner. This article presents a variety of measuring and control systems that have been tailored to this particular task, able to increase the efficiency of both, existing older installations and new burner systems. (orig.)

Evaluation of a high-temperature burner-duct-recuperator system

Science.gov (United States)

1990-07-01

The U.S. Department of Energy's (DOE) Office of Industrial Technologies (OIT) sponsors research and development (R and D) to improve the energy efficiency of American industry and to provide for fuel flexibility. OIT has funded a multiyear R and D project by the Babcock and Wilcox Company (B and W) to design, fabricate, field test, and evaluate a high-temperature burner-duct-recuperator (HTBDR) system. This ceramic-based recuperator system recovers waste heat from the corrosive, high-temperature (2170 F) flue gas stream of a steel soaking pit to preheat combustion air to as high as 1700 F. The preheated air is supplied to a high-temperature burner. The B and W R and D program, which is now complete, involved several activities, including selecting and evaluating ceramic materials, designing the system, and developing and evaluating the prototype. In addition, a full-scale unit was tested at a B and W steel soaking pit. The full-scale system consisted of a modular single-stage ceramic recuperator, a conventional two-pass metallic recuperator, a high-temperature burner, fans, insulated ducting, and associated controls and instrumentation. The metallic recuperator preheated combustion air to about 750 F before it passed to the ceramic module. This technical case study describes the DOE/B and W recuperator project and highlights the field tests of the full-scale recuperator system. The document makes results of field tests and data analysis available to other researchers and private industry. It discusses project status, summarizes field tests, and reviews the potential effects the technology will have on energy use and system economics.

Studies of air plasma techniques in mutating Penicillium chrysogenum

International Nuclear Information System (INIS)

Gui Fang; Liu Hui; Wang Hui; Wang Peng; Yuan Chengling; Zheng Zhiming

2011-01-01

penicillin producing strain Penicillium chrysogenum Pc05 as the starting strain was mutated by low-temperature air plasma technology. As the result revealed, in 30 minutes, the survival rate of spores followed the saddle-shaped curve. The positive mutants accounted for 44.19% of all mutants while the negative mutation was low. After primary and secondary screening, the mutant aPc051310 was obtained, and eventually its penicillin titer increased 42.1% compared with that of starting strain. Synergetic effect between chemical reactive species and charged particles was considered as the main mutation mechanism involved in low temperature air plasma. All the results have been proved that as a new industrial microbial strains mutation method, low temperature air plasma has potential applications. (authors)

Chemical composition, sources and secondary processes of aerosols in Baoji city of northwest China

Science.gov (United States)

Wang, Y. C.; Huang, R.-J.; Ni, H. Y.; Chen, Y.; Wang, Q. Y.; Li, G. H.; Tie, X. X.; Shen, Z. X.; Huang, Y.; Liu, S. X.; Dong, W. M.; Xue, P.; Fröhlich, R.; Canonaco, F.; Elser, M.; Daellenbach, K. R.; Bozzetti, C.; El Haddad, I.; Prévôt, A. S. H.; Canagaratna, M. R.; Worsnop, D. R.; Cao, J. J.

2017-06-01

Particulate air pollution is a severe environmental problem in China, affecting visibility, air quality, climate and human health. However, previous studies focus mainly on large cities such as Beijing, Shanghai, and Guangzhou. In this study, an Aerodyne Aerosol Chemical Speciation Monitor was deployed in Baoji, a middle size inland city in northwest China from 26 February to 27 March 2014. The non-refractory submicron aerosol (NR-PM1) was dominated by organics (55%), followed by sulfate (16%), nitrate (15%), ammonium (11%) and chloride (3%). A source apportionment of the organic aerosol (OA) was performed with the Sofi (Source Finder) interface of ME-2 (Multilinear Engine), and six main sources/factors were identified and classified as hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), coal combustion OA (CCOA), less oxidized oxygenated OA (LO-OOA) and more oxidized oxygenated OA (MO-OOA), which contributed 20%, 14%, 13%, 9%, 23% and 21% of total OA, respectively. The contribution of secondary components shows increasing trends from clean days to polluted days, indicating the importance of secondary aerosol formation processes in driving particulate air pollution. The formation of LO-OOA and MO-OOA is mainly driven by photochemical reactions, but significantly influenced by aqueous-phase chemistry during periods of low atmospheric oxidative capacity.

The changing face of urban air pollution

Science.gov (United States)

Lewis, Alastair C.

2018-02-01

The atmospheric chemistry that leads to photochemical smog and climate-active aerosols requires the presence of volatile organic compounds (VOCs) (1, 2). The VOCs in urban air typically derive from the prevailing energy and transport technologies as well as the use of petrochemical-derived products. On page 760 of this issue, McDonald et al. (3) report that a notable change in emissions may be underway in U.S. cities, with effects on secondary pollutants such as organic aerosols. Shifting from an urban atmosphere dominated by transport-related VOCs to one dominated by VOCs from coatings, adhesives, and consumer products would alter predictions of urban air quality and challenge the existing policy framework for emissions control.

Nutritional Solutions to Reduce Risks of Negative Health Impacts of Air Pollution

OpenAIRE

Szabolcs Péter; Fernando Holguin; Lisa G. Wood; Jane E. Clougherty; Daniel Raederstorff; Magda Antal; Peter Weber; Manfred Eggersdorfer

2015-01-01

Air pollution worldwide has been associated with cardiovascular and respiratory morbidity and mortality, particularly in urban settings with elevated concentrations of primary pollutants. Air pollution is a very complex mixture of primary and secondary gases and particles, and its potential to cause harm can depend on multiple factors?including physical and chemical characteristics of pollutants, which varies with fine-scale location (e.g., by proximity to local emission sources)?as well as l...

Effects of N{sub 2} gas on preheated laminar LPG jet diffusion flame

Energy Technology Data Exchange (ETDEWEB)

Mishra, D.P.; Kumar, P. [Department of Aerospace Engineering, Indian Institute of Technology, Kanpur 208 016 (India)

2010-11-15

This paper presents an experimental investigation of the inert gas effect on flame length, NO{sub x} and soot free length fraction (SFLF) in a laminar LPG diffusion flame. Besides this, flame radiant fraction and temperature are also measured to explain observed NO{sub x} emission and SFLF. The inert is added to both air and fuel stream at each base line condition by maintaining a constant mass flow rate in each stream. Results indicate that inert addition leads to a significant enhancement in flame length for air-diluted stream than fuel-diluted stream. However, the flame length is observed to reduce with increasing reactant temperature. It is also observed that the SFLF increases with addition of N{sub 2} for fuel-diluted stream. In contrast, SFLF remains almost constant when N{sub 2} is added to air stream. The decrease in fuel concentration and gas temperature caused by inert addition leads to reduction in soot volume fraction and hence enhances SFLF. Interestingly, the SFLF reduces with increasing reactant temperature, due to reduction in induction period of soot formation caused by enhanced flame temperature. Besides this, the reduction in NO{sub x} emission level with inert addition is also observed. For all the three cases, the air dilution proved to be much efficient in reducing NO{sub x} emission level as compared to fuel dilution. This can be attributed to the differences in reduced gas temperature and residence time between air and fuel-diluted streams. On the contrary, NO{sub x} emission level enhances significantly with increasing reactant temperature as a result of increase in thermal NO{sub x} through Zeldovich mechanism. (author)

Results from study of potential early commercial MHD power plants and from recent ETF design work. [Engineering Test Facility

Science.gov (United States)

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1980-01-01

The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched combustion air. Performance calculations show that an overall power plant efficiency of the order of 44% can be reached with the use of oxygen enrichment.

Results from study of potential early commercial MHD power plants and from recent ETF design work

Science.gov (United States)

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1980-06-01

The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched combustion air. Performance calculations show that an overall power plant efficiency of the order of 44% can be reached with the use of oxygen enrichment.

High pressure MHD coal combustors investigation, phase 2

Science.gov (United States)

Iwata, H.; Hamberg, R.

1981-05-01

A high pressure MHD coal combustor was investigated. The purpose was to acquire basic design and support engineering data through systematic combustion experiments at the 10 and 20 thermal megawatt size and to design a 50 MW/sub t/ combustor. This combustor is to produce an electrically conductive plasma generated by the direct combustion of pulverized coal with hot oxygen enriched vitiated air that is seeded with potassium carbonate. Vitiated air and oxygen are used as the oxidizer, however, preheated air will ultimately be used as the oxidizer in coal fired MHD combustors.

Impact of preheating on the behavior of Listeria monocytogenes in a broth that mimics Camembert cheese composition.

Science.gov (United States)

Helloin, E; Bouttefroy, A; Gay, M; Phan Thanh, L

2003-02-01

The effect of preheating on the survival of L. monocytogenes in Richard's broth, which mimics the composition of Camembert cheese composition, was examined. Experiments were carried out to reproduce contamination of cheese with environmental heat-stressed cells of L. monocytogenes surviving hot-cleaning procedures. Cells in mid-log phase were heated for 30 min at 56 degrees C before being inoculated into Richard's broth. The pHs and temperatures of Richard's broth were chosen to recreate the conditions of curd dripping (pH 5, 25 degrees C), of the beginning of cheese ripening (pH 5, 12 degrees C), and of the beginning (pH 5, 4 degrees C) and the end (pH 7, 4 degrees C) of cheese storage. Immediately after heat treatment, the viability loss was especially high for strain 306715, which exhibited only 0.6% +/- 0.2% survival, compared with 22% +/- 8.7% for strain EGD. The percentages of the surviving heated cells that were injured were 93% +/- 8% for strain 306715 and 98% +/- 3% for strain EGD. The destruction of the surviving L. monocytogenes cells was accelerated when they encountered the pH and temperature conditions of Camembert cheese during manufacturing, ripening, and cold storage (pH 5 at 25, 12, and 4 degrees C, respectively). The multiplication of the surviving heated cells was retarded under favorable growth conditions similar to those of storage by the distributor and the consumer (pH 7 at 4 and 12 degrees C, respectively).

Impact of meteorological conditions on airborne fine particle composition and secondary pollutant characteristics in urban area during winter-time

Directory of Open Access Journals (Sweden)

Klaus Schäfer

2016-06-01

Full Text Available The assessment of airborne fine particle composition and secondary pollutant characteristics in the case of Augsburg, Germany, during winter (31 January–12 March 2010 is studied on the basis of aerosol mass spectrometry (3 non-refractory components and organic matter, 3 positive matrix factorizations (PMF factors, particle size distributions (PSD, 5 size modes, 5 PMF factors, further air pollutant mass concentrations (7 gases and VOC, black carbon, PM10, PM2.5 and meteorological measurements, including mixing layer height (MLH, with one-hourly temporal resolution. Data were subjectively assigned to 10 temporal phases which are characterised by different meteorological influences and air pollutant concentrations. In each phase hierarchical clustering analysis with the Ward method was applied to the correlations of air pollutants, PM components, PM source contributions and PSD modes and correlations of these data with all meteorological parameters. This analysis resulted in different degrees of sensitivities of these air pollutant data to single meteorological parameters. It is generally found that wind speed (negatively, MLH (negatively, relative humidity (positively and wind direction influence primary pollutant and accumulation mode particle (size range 100–500 nm concentrations. Temperature (negatively, absolute humidity (negatively and also relative humidity (positively are relevant for secondary compounds of PM and particle (PM2.5, PM10 mass concentrations. NO, nucleation and Aitken mode particle and the fresh traffic aerosol concentrations are only weakly dependent on meteorological parameters and thus are driven by emissions. These daily variation data analyses provide new, detailed meteorological influences on air pollutant data with the focus on fine particle composition and secondary pollutant characteristics and can explain major parts of certain PM component and gaseous pollutant exposure.

Combustion performance evaluation of air staging of palm oil blends.

Science.gov (United States)

Mohd Jaafar, Mohammad Nazri; Eldrainy, Yehia A; Mat Ali, Muhammad Faiser; Wan Omar, W Z; Mohd Hizam, Mohd Faizi Arif

2012-02-21

The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber.

High secondary aerosol contribution to particulate pollution during haze events in China

Science.gov (United States)

Huang, Ru-Jin; Zhang, Yanlin; Bozzetti, Carlo; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Daellenbach, Kaspar R.; Slowik, Jay G.; Platt, Stephen M.; Canonaco, Francesco; Zotter, Peter; Wolf, Robert; Pieber, Simone M.; Bruns, Emily A.; Crippa, Monica; Ciarelli, Giancarlo; Piazzalunga, Andrea; Schwikowski, Margit; Abbaszade, Gülcin; Schnelle-Kreis, Jürgen; Zimmermann, Ralf; An, Zhisheng; Szidat, Sönke; Baltensperger, Urs; Haddad, Imad El; Prévôt, André S. H.

2014-10-01

Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.

Plasma-spraying synthesis of high-performance photocatalytic TiO2 coatings

International Nuclear Information System (INIS)

Takahashi, Yasuo; Maeda, Masakatsu; Ohmori, Akira; Shibata, Yoshitaka; Miyano, Yasuyuki; Murai, Kensuke

2014-01-01

Anatase (A-) TiO 2 is a photocatalytic material that can decompose air-pollutants, acetaldehyde, bacteria, and so on. In this study, three kinds of powder (A-TiO 2 without HAp, TiO 2 + 10mass%HAp, and TiO 2 +30mass%HAp, where HAp is hydroxyapatite and PBS is polybutylene succinate) were plasma sprayed on biodegradable PBS substrates. HAp powder was mixed with A-TiO 2 powder by spray granulation in order to facilitate adsorption of acetaldehyde and bacteria. The crystal structure was almost completely maintained during the plasma spray process. HAp enhanced the decomposition of acetaldehyde and bacteria by promoting adsorption. A 10mass% HAp content was the most effective for decomposing acetaldehyde when plasma preheating of the PBS was not carried out before the plasma spraying. The plasma preheating of PBS increased the yield rate of the spray process and facilitated the decomposition of acetaldehyde by A-TiO 2 coatings without HAp. HAp addition improved photocatalytic sterilization when plasma preheating of the PBS was performed

Solar project description for Moulder Corporation single family residence, Greenwood, Indiana

Science.gov (United States)

1980-07-01

The system is designed to provide solar energy for space heating and domestic hot water heating. Solar energy is used for space heating the home and preheating domestic hot water (DHW). The solar energy system has an array of flat plate collectors with a gross area of 704 square feet. The array faces 5.5 degrees west of south at an angle of 45 degrees to the horizontal. Air is the transfer medium that delivers solar energy from the collector array to storage, space heating and hot water loads. Solar energy is stored underground in 945 cubic foot bin containing 81,000 pounds of crushed rock. The bin has 8 inch concrete block walls and the insulation on the exterior is sprayed urethane. Preheated city water is stored in an 80 gallon preheat tank, which is inside the storage bin and is supplied, on demand, to a conventional 52 gallon DHW tank. When solar energy is insufficient to satisfy the space heating load, a conventional electric furnace provides the auxiliary energy for space heating.

Time-resolved analysis of primary volatile emissions and secondary aerosol formation potential from a small-scale pellet boiler

Science.gov (United States)

Czech, Hendryk; Pieber, Simone M.; Tiitta, Petri; Sippula, Olli; Kortelainen, Miika; Lamberg, Heikki; Grigonyte, Julija; Streibel, Thorsten; Prévôt, André S. H.; Jokiniemi, Jorma; Zimmermann, Ralf

2017-06-01

Small-scale pellet boilers and stoves became popular as a wood combustion appliance for domestic heating in Europe, North America and Asia due to economic and environmental aspects. Therefore, an increasing contribution of pellet boilers to air pollution is expected despite their general high combustion efficiency. As emissions of primary organic aerosol (POA) and permanent gases of pellet boilers are well investigated, the scope of this study was to investigate the volatile organic emissions and the formation potential of secondary aerosols for this type of appliance. Fresh and aged emissions were analysed by a soot-particle aerosol time-of-flight mass spectrometry (SP-AMS) and the molecular composition of the volatile precursors with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) at different pellet boiler operation conditions. Organic emissions in the gas phase were dominated by unsaturated hydrocarbons while wood-specific VOCs, e.g. phenolic species or substituted furans, were only detected during the starting phase. Furthermore, organic emissions in the gas phase were found to correlate with fuel grade and combustion technology in terms of secondary air supply. Secondary organic aerosols of optimised pellet boiler conditions (OPT, state-of-the-art combustion appliance) and reduced secondary air supply (RSA, used as a proxy for pellet boilers of older type) were studied by simulating atmospheric ageing in a Potential Aerosol Mass (PAM) flow reactor. Different increases in OA mass (55% for OPT, 102% for RSA), associated with higher average carbon oxidation state and O:C, could be observed in a PAM chamber experiment. Finally, it was found that derived SOA yields and emission factors were distinctly lower than reported for log wood stoves.

A study of air breathing rockets. 3: Supersonic mode combustors

Science.gov (United States)

Masuya, G.; Chinzel, N.; Kudo, K.; Murakami, A.; Komuro, T.; Ishii, S.

An experimental study was made on supersonic mode combustors of an air breathing rocket engine. Supersonic streams of room-temperature air and hot fuel-rich rocket exhaust were coaxially mixed and burned in a concially diverging duct of 2 deg half-angle. The effect of air inlet Mach number and excess air ratio was investigated. Axial wall pressure distribution was measured to calculate one dimensional change of Mach number and stagnation temperature. Calculated results showed that supersonic combustion occurred in the duct. At the exit of the duct, gas sampling and Pitot pressure measurement was made, from which radial distributions of various properties were deduced. The distribution of mass fraction of elements from rocket exhaust showed poor mixing performance in the supersonic mode combustors compared with the previously investigated cylindrical subsonic mode combustors. Secondary combustion efficiency correlated well with the centerline mixing parameter, but not with Annushkin's non-dimensional combustor length. No major effect of air inlet Mach number or excess air ratio was seen within the range of conditions under which the experiment was conducted.

Changes of main secondary metabolites in leaves of Ginkgo biloba in response to ozone fumigation

Institute of Scientific and Technical Information of China (English)

HE Xingyuan; HUANG Wei; CHEN Wei; DONG Tian; LIU Changbing; CHEN Zhenju; XU Sheng; RUAN Yanan

2009-01-01

To investigate the effect of elevated O3 on the accumulation of main secondary metabolites in leaves of Ginkgo biloba L., four-year-old trees were exposed in open-top chambers with ambient air and the air with twice ambient O3 concentration in Shenyang in 2006.Elevated O3 increased the concentrations of terpenes, but decreased the concentrations of phenolics in G.biloba leaves.The results showed that secondary compounds from G.biloba leaves responded to the elevated O3 exposure in a different way when compared to previous studies which showed elevated O3 increased the concentrations of phenolics but had no effect on the terpenes in leaves of other deciduous trees.Furthermore, reduced synthesis of phenolics may decrease the resistance of G.biloba to O3 and other environmental factors.On the other hand, the induced synthesis of terpenes may enhance the antioxidant abilities in G.biloba leaves at the end of O3 fumigation.

Mesenteric Air Embolism Following Enteroscopic Small Bowel Tattooing Procedure

Directory of Open Access Journals (Sweden)

Natalie Chen

2012-01-01

Full Text Available Double balloon enteroscopy (DBE is a revolutionary procedure in which the entire small bowel can be visualized endoscopically. DBE has the advantage of both diagnostic and therapeutic capabilities in the setting of small bowel neoplasms and vascular malformations. We present a unique case of a 76-year-old female who underwent small bowel DBE tattoo marking of a distal small bowel tumor complicated by development of severe abdominal pain postprocedure secondary to bowel air embolism into the mesenteric veins. Mesenteric air can be seen after other endoscopic procedures such as biopsy, mucosal clip placement and polypectomy, or following a colonoscopy. Mesenteric air embolism following small bowel tattooing procedure has not been previously reported in the literature. Mesenteric air when present may be attributed to mesenteric ischemia and can subject the patient to unnecessary surgical intervention if misdiagnosed. Thus, this report holds significance for the radiologist as computed tomography (CT findings of mesenteric air embolism must be evaluated in the context of appropriate clinical history before treatment decisions are made.

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

OpenAIRE

Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

2016-01-01

An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is d...

Comparative analysis of aluminum-air battery propulsion systems for passenger vehicles

Science.gov (United States)

Salisbury, J. D.; Behrin, E.; Kong, M. K.; Whisler, D. J.

1980-02-01

Three electric propulsion systems using an aluminum air battery were analyzed and compared to the internal combustion engine (ICE) vehicle. The engine and fuel systems of a representative five passenger highway vehicle were replaced conceptually by each of the three electric propulsion systems. The electrical vehicles were constrained by the computer simulation to be equivalent to the ICE vehicle in range and acceleration performance. The vehicle masses and aluminum consumption rates were then calculated for the electric vehicles and these data were used as figures of merit. The Al-air vehicles analyzed were (1) an Al-air battery only electric vehicle; (2) an Al-air battery combined with a nickel zinc secondary battery for power leveling and regenerative braking; and (3) an Al-air battery combined with a flywheel for power leveling and regenerative braking. All three electric systems compared favorably with the ICE vehicle.

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

International Nuclear Information System (INIS)

Adu-Wusu, K

2006-01-01

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

Infant otitis media and the use of secondary heating sources.

Science.gov (United States)

Pettigrew, Melinda M; Gent, Janneane F; Triche, Elizabeth W; Belanger, Kathleen D; Bracken, Michael B; Leaderer, Brian P

2004-01-01

This prospective study investigated the association of exposure to indoor secondary heating sources with otitis media and recurrent otitis media risk in infants. We enrolled mothers living in nonsmoking households and delivering babies between 1993 and 1996 in 12 Connecticut and Virginia hospitals. Biweekly telephone interviews during the first year of life assessed diagnoses from doctors' office visits and use of secondary home heating sources, air conditioner use, and day care. Otitis media episodes separated by more than 21 days were considered to be unique episodes. Recurrent otitis media was defined as 4 or more episodes of otitis media. Repeated-measures logistic regression modeling evaluated the association of kerosene heater, fireplace, or wood stove use with otitis media episodes while controlling for potential confounders. Logistic regression evaluated the relation of these secondary heating sources with recurrent otitis media. None of the secondary heating sources were associated with otitis media or with recurrent otitis media. Otitis media was associated with day care, the winter heating season, birth in the fall, white race, additional children in the home, and a maternal history of allergies in multivariate models. Recurrent otitis media was associated with day care, birth in the fall, white race, and a maternal history of allergies or asthma. We found no evidence that the intermittent use of secondary home heating sources increases the risk of otitis media or recurrent otitis media. This study confirms earlier findings regarding the importance of day care with respect to otitis media risk.

Range-extending Zinc-air battery for electric vehicle

Directory of Open Access Journals (Sweden)

Steven B. Sherman

2018-01-01

Full Text Available A vehicle model is used to evaluate a novel powertrain that is comprised of a dual energy storage system (Dual ESS. The system includes two battery packs with different chemistries and the necessary electronic controls to facilitate their coordination and optimization. Here, a lithium-ion battery pack is used as the primary pack and a Zinc-air battery as the secondary or range-extending pack. Zinc-air batteries are usually considered unsuitable for use in vehicles due to their poor cycle life, but the model demonstrates the feasibility of this technology with an appropriate control strategy, with limited cycling of the range extender pack. The battery pack sizes and the battery control strategy are configured to optimize range, cost and longevity. In simulation the vehicle performance compares favourably to a similar vehicle with a single energy storage system (Single ESS powertrain, travelling up to 75 km further under test conditions. The simulation demonstrates that the Zinc-air battery pack need only cycle 100 times to enjoy a ten-year lifespan. The Zinc-air battery model is based on leading Zinc-air battery research from literature, with some assumptions regarding achievable improvements. Having such a model clarifies the performance requirements of Zinc-air cells and improves the research community's ability to set performance targets for Zinc-air cells.

Numerical and Experimental Characterization of a Composite Secondary Bonded Adhesive Lap Joint Using the Ultrasonics method

Science.gov (United States)

Kumar, M. R.; Ghosh, A.; Karuppannan, D.

2018-05-01

The construction of aircraft using advanced composites have become very popular during the past two decades, in which many innovative manufacturing processes, such as cocuring, cobonding, and secondary bonding processes, have been adopted. The secondary bonding process has become less popular than the other two ones because of nonavailability of process database and certification issues. In this article, an attempt is made to classify the quality of bonding using nondestructive ultrasonic inspection methods. Specimens were prepared and tested using the nondestructive ultrasonic Through Transmission (TT), Pulse Echo (PE), and air coupled guided wave techniques. It is concluded that the ultrasonic pulse echo technique is the best one for inspecting composite secondary bonded adhesive joints.

21 CFR 172.886 - Petroleum wax.

Science.gov (United States)

2010-04-01

... availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register... it is very hygroscopic and will react with some metal containers in the presence of air. Phosphoric... high enough to keep the wax melted. (Note: In preheating the sulfoxide-acid mixture, remove the stopper...

Underground gasification in Britain

Energy Technology Data Exchange (ETDEWEB)