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Sample records for ash flow temperature

  1. Manipulation of the ash flow temperature and viscosity of a carbonaceous Sasol waste stream

    Energy Technology Data Exchange (ETDEWEB)

    J.C. van Dyk; M.J. Keyser; F.B. Waanders; M. Conradie [Syngas and Coal Technologies, Sasolburg (South Africa). Sasol Technology, R& amp; D Division

    2010-01-15

    In 2001 Sasol investigated selected the Lurgi Multi Purpose Gasification (MPG) process for converting a Sasol-Lurgi MK III fixed bed dry bottom coal gasifier at the former Sasolburg coal-to-liquids plant to a slagging gasification process. The MPG process was considered anoption suitable for the gasification of feedstocks which are difficult to manage. The most obvious differences between the feedstocks previously gasified, compared to the Sasol dusty tar, were found to be the viscosity and melting point of the dusty tar. The viscosity of the Sasol dusty tar mixture was higher than a factor of 10 ofpreviously used feedstocks. Another important feedstock property is the ash melting point of the feed within the gasifier. Ash particles fed with the tar melt in the high temperature zone of the flame. Molten ash particles which hit the gasifier wall will solidify and stick to the wall if the wall temperature is below the melting point of the ash. The melting point of the dusty tar ash is 1380{sup o}C and a fluxing agent has to be added to reduce the melting temperature below 1250{sup o}C to limit excessive wear of the refractory lining. It was concluded that the viscosity of dusty tar can be decreased with the addition of specific waste solvent streams. The ash fusion temperatures of dusty tar can be lowered by adding a fluxing agent. The addition of spent Fe-catalyst as fluxing agent was found to be less effective than limestone. The addition of Fe can cause the acid/base ratio to change so that the ash fusion temperature increases. The results show in both oxidizing and reducing atmospheres the Fe-catalyst was transformed into the slag melt as either Fe{sub 2}O{sub 3} under oxidizing conditions and FeO under reducing conditions. The slag showed no sign of metallic Fe and was very homogeneous under oxidizing and reducing conditions. 17 refs., 7 figs., 8 tabs.

  2. The Influence Of Calcite On The Ash Flow Temperature For Semi-Anthracite Coal From Donbas District

    Directory of Open Access Journals (Sweden)

    Čarnogurská Mária

    2014-12-01

    Full Text Available This paper presents the results of research focused on the lowering of ash flow temperature at semianthracite coal from Donbas district by means of additive (calcite dosing. Ash fusion temperatures were set for two coal samples (A, B and for five various states (samples of ash without any additives, with 1%, with 3%, with 5% and with 7% of the additive in total. The macroscopicphotographic method was used for identifying all specific temperatures. Obtained outputs prove that A type coal has a lower value of sphere temperature than B type coal in the whole scope of percentage representation of the additive. The flow temperature dropped in total from 1489 °C to 1280 °C, i.e. by 14% during the test of coal of type A with 7% of the additive; while it was near 10% for coal of type B (from 1450 °C to 1308 °C. Numerical simulations of the process showed that it is not effective to add an additive with a grain size lower than 280 μm by means of wastevapour burners.

  3. High-temperature, large-volume, lavalike ash-flow tuffs without calderas in southwestern Idaho

    Science.gov (United States)

    Ekren, E.B.; McIntyre, David H.; Bennett, Earl H.

    1984-01-01

    Rhyolitic rocks were erupted from vents in and adjacent to the Owyhee Mountains and Owyhee Plateau of southwestern Idaho from 16 m.y. ago to about 10 m.y. ago. They were deposited on a highly irregular surface developed on a variety of basement rocks that include granitic rocks of Cretaceous age, quartz latite and rhyodacite tuffs and lava flows of Eocene age, andesitic and basaltic lava flows of Oligocene age, and latitic and basaltic lava flows of early Miocene age. The rhyolitic rocks are principally welded tuffs that, regardless of their source, have one feature in common-namely internal characteristics indicating en-masse, viscous lavalike flowage. The flowage features commonly include considerable thicknesses of flow breccia at the bases of various cooling units. On the basis of the tabular nature of the rhyolitic deposits, their broad areal extents, and the local preservation of pyroclastic textures at the bases, tops, and distal ends of some of the deposits, we have concluded that the rocks were emplaced as ash flows at extremely high temperatures and that they coalesced to liquids before final emplacement and cooling. Temperatures of l090?C and higher are indicated by iron-titanium oxide compositions. Rhyolites that are about 16 m.y. old are preserved mostly in the downdropped eastern and western flanks of the Silver City Range and they are inferred to have been erupted from the Silver City Range. They rarely contain more than about 2 percent phenocrysts that consist of quartz and subequal amounts of plagioclase and alkali feldspar; commonly, they contain biotite, and they are the only rhyolitic rocks in the area to do so. The several rhyolitic units that are 14 m.y. to about 10 m.y. old contain only pyroxene-principally ferriferous and intermediate pigeonites-as mafic constituents. The rhyolites of the Silver City Range comprise many cooling units, none of which can be traced for great distances. Rocks erupted from the Owyhee Plateau include two sequences

  4. ASH MELTING TEMPERATURE PREDICTION FROM CHEMICAL COMPOSITION OF BIOMASS ASH

    OpenAIRE

    Holubcik, Michal; Jandacka, Jozef; Malcho, Milan

    2015-01-01

    Solid fuels, including biomass, consist of combustible, ash and water. Ash in fuel is result of reaction of minerals presented in the biomass. Minerals and other different substances which form ash got into biomass during growth. Ash is solid residue resulted from the perfect laboratory combustion of fuel. It is composed of minerals that are present in the fuel. Some species of biomass ash have low ash melting temperature and can cause various problems in combustion boilers. Ash slags and sin...

  5. Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Peter Y. [National Energy Technology Lab. (NETL), Albany, OR (United States); Kwong, Kyei-Sing [National Energy Technology Lab. (NETL), Albany, OR (United States); Bennett, James [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2015-09-27

    Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. Here, we measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. We made all measurements in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. Finally, an understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.

  6. Gasification of high ash, high ash fusion temperature bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  7. Effect of refractory agent on ash fusibility temperatures of briquette

    Institute of Scientific and Technical Information of China (English)

    Guo-xing CUI; Kui HUANG; Ming-sui LIN

    2013-01-01

    To solve the problem of the low ash fusion point of briquette,this paper reported that the ash fusibility temperatures can be elevated by changing ash ingredients through blending refractory agents in briquette ash,which will create favorable conditions for moving bed continuous gasification of briquette with oxygen-rich air.The effects of Al2O3,SiO2,kaolin,dry powder and bentonite on ash fusibility temperatures were studied,based upon the relationship between briquette ash components and ash fusibility.The results show that the increasing of ash fusibility temperatures by adding the same amount (11%,w)of refractory agents follows the sequence of SiO2,bentonite,dry powder,kaolin,Al2O3,with the softening temperatures beingelevated by 37.2,57.6,60.4,82.6 and 104.4 ℃.With the same ratio of SiO2/Al2O3 in briquette,adding the Al2O3 component is more effective than SiO2 for raising ash fusibility temperatures.In this paper,inexpensive kaolin and bentonite rich in Al2O3 are found to be better refractory agents,and the suitable adding quantities are 9% and 11%,respectively.

  8. Pyritic ash-flow tuff, Yucca Mountain, Nevada -- A discussion

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, S.I.; Larson, L.T.; Noble, D.C. [Univ. of Nevada, Reno, NV (United States)

    1994-12-31

    Textural and mineralogic evidence exists for at least one episode of widespread hydrothermal alteration of volcanic rocks deep in Yucca Mountain, Nevada. Despite this evidence, Castor et al. infer that most of the pyrite found in tuffs at Yucca Mountain was introduced as ejecta (lithic fragments) incorporated during the eruptions of the tuffs, rather than by in-situ hydrothermal activity. Their conclusions appear to be based on their observation that most of the pyrite resides in unaltered to variably altered and veined lithic fragments, whereas pyrite-bearing veins are absent in the tuff matrix, titanomagnetite and mafic phenocrysts in the matrix are generally not replaced by pyrite, and feldspar phenocrysts in the pyritic tuff matrix are generally unaltered. Castor et al. dismiss the much smaller quantities of pyrite disseminated in the tuff matrix, including relatively rare pyritized hornblende and biotite grains, as xenolithic as well. The pyritic tuffs belong to large-volume, subalkaline rhyolite ash-flow units (ca. > 150 to 250 km{sup 3} each). The interpretation of Castor et al. has broad implications for the temperature, fO{sub 2} and fS{sub 2} of major ash flow eruptions. Pyrite origin also bears on the nature of past fluid flow and water-rock reactions at Yucca Mountain, which in turn are important factors in assessing the potential for currently undiscovered mineral resources in the area of the proposed nuclear waste repository. We have studied core and cuttings from the same drill holes studied by Castor et al., as well as other drill holes. It is our contention that the inconsistent lateral and stratigraphic distribution of the pyrite, textural features of the pyrite, and phase stability considerations are incompatible with the {open_quotes}lithic{close_quotes} origin of Castor et al., and are more reasonably explained by in-situ formation from hydrothermal fluids containing low, but geochemically significant, concentrations of reduced sulfur.

  9. Pena Blanca uranium deposits and ash-flow tuffs relationship

    International Nuclear Information System (INIS)

    The Pena Blanca uranium deposits (Chihuahua, Mexico) are associated with a Tertiary sequence of ash-flow tuffs. Stratigraphic control is dominant and uranium mineralization occurs in stratiform and fracture-controlled deposits within 44 My-old units: Nopal Rhyolite and Escuadra Rhyolite. These units consist of highly vapor-phase crystallized ash-flow tuffs. They contain sanidine, quartz and granophyric phenocrysts, and minor ferromagnesian silicates. Nopal and Escuadra units are high-silica alkali-rich rhyolites that have a primary potassic character. The trace-element chemistry shows high concentrations in U-Th-Rb-Cs and low contents in Ba-Sr-Eu. These chemical properties imply a genetic relationship between deposits and host-units. The petrochemical study show that the Nopal Rhyolite and Escuadra Rhyolite are the source of U and of hydrothermal solutions

  10. Behavior of HPC with Fly Ash after Elevated Temperature

    OpenAIRE

    Huai-Shuai Shang; Ting-Hua Yi

    2013-01-01

    For use in fire resistance calculations, the relevant thermal properties of high-performance concrete (HPC) with fly ash were determined through an experimental study. These properties included compressive strength, cubic compressive strength, cleavage strength, flexural strength, and the ultrasonic velocity at various temperatures (20, 100, 200, 300, 400 and 500∘C) for high-performance concrete. The effect of temperature on compressive strength, cubic compressive strength, cleavage strength,...

  11. High temperature co-treatment of bottom ash and stabilized fly ashes from waste incineration

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Mogensen, E.P.B.; Lundtorp, Kasper;

    2001-01-01

    Bottom ashes from two Danish municipal solid waste incineration plants were heated at 900 degreesC with iron oxide stabilized air pollution control residues at actual mass flow ratios (9:1), simulating a treating method for the residues. The two residues were cotreated, producing one combined...... stream that may be utilized as a secondary road construction material. Scanning electron microscope analysis and grain size distribution analysis indicated that sintering of the particles did not occur. Batch leaching tests at liquid/solid 10 I/kg at a range of pH-values (6-10) quantified with respect to...

  12. Effects of mineralizers on fusion temperature of domestic coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jin-Wook; Han, Choon [Kwangwoon University, Seoul(Korea); Lim, Byeong-Seon [Korea Bosch Ltd., Seoul(Korea); Lee, Myoung-Sup; Lee, Sang-Hoon [Korea Resources Corp., Seoul(Korea); Lee, Bong-Han; Yoo, Jae-Sang; Seo, Hyoung-Seok [Ssangyong Cement Industrial Co., Ltd., Seoul(Korea)

    2001-12-31

    Considering compositions, domestic coal ash can be used as raw material for cement. However, the high fusion temperature of domestic coal ash(>1600 deg.C) prohibits using because the combustion temperature of clinker is around 1450 deg.C. Therefore, mineralizers are needed to lower the ash fusion temperature(AFT) and effects of mineralizers were investigated in this study. For three coal ashes from Tae-baek area, pure and mixed mineralizers(CaO, MgO, Fe{sub 2}O{sub 3}, Na{sub 2}CO{sub 3}) were added. Results showed that AFT were lowered to around 1450 deg.C by adding CaO 5-8 wt.%(1360-1471 deg.C), MgO 2-5 wt.%(1360-1480 deg.C), and Fe{sub 2}O{sub 3} 2-5 wt.%(1395-1490 deg.C) respectively. Especially, the lowest AFT(1120-1147 deg.C) could be achieved by adding 30 to 40 wt.% of CaO. When 20 to 30 wt.% of mixed mineralizers(CaO : MgO = 1 : 1) were added, AFT was lowered to 1130-1153 deg.C which was the lowest temperature with mixed mineralizer. Also, CaO was recognized as the governing mineralizer on AFT. Recognizing that basic oxides took the main role of mineralizers, the model equation was proposed to estimate AFT. Consequently, simulated results by the model equation represented the measured AFT successfully. (author). 12 refs., 4 tabs., 8 figs.

  13. A high temperature granulation process for ecological ash recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Sundqvist, Thomas

    1999-07-01

    This thesis is a summary of three papers dealing with new technologies for facilitating ecological biomass ash recirculation back to forest and farm lands. The present outtake of biomass for paper and energy production may be incompatible with a sustainable forestry. The cycle of nutrients contained in the biomass extracted must be closed by ash recirculation in an environmental compatible way. This implies stabilization of the loose ashes/rest-products to a product with low heavy metal contents, controlled leaching properties and a high spreadability. In the present work, two different techniques were evaluated for the possibilities to separate heavy metals from the nutrient elements by utilizing high process temperatures to vaporize the unwanted metals from the condensed bulk materials. The results indicated that direct in-situ separation in fluidized bed combustion systems is possible, but requires too high process temperatures to be practically attractive. On the other hand, the new proposed high temperature treatment method for granulated raw materials was found to significantly separate As, Cd and Pb, with separation efficiencies exceeding 90 % at optimal operating conditions. In addition, the results indicated that the treatment method could be used to significantly delay and control the leaching characteristics, as well as the content of products of incomplete combustion of the produced granules.

  14. Pyritic ash-flow tuff, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    The Yucca Mountain site is underlain by a 1,500-m-thick Miocene volcanic sequence that comprises part of the southwestern Nevada volcanic field. Rocks of this sequence, which consists mainly of ash-flow tuff sheets with minor flows and bedded tuff, host precious metal mineralization in several areas as near as 10 km from the site. In two such areas, the Bullfrog and Bare Mountain mining districts, production and reserves total over 60 t gold and 150 t silver. Evidence of similar precious metal mineralization at the Yucca Mountain site may lead to mining or exploratory drilling in the future, compromising the security of the repository. The authors believe that most of the pyrite encountered by drilling at Yucca Mountain was introduced as pyroclastic ejecta, rather than by in situ hydrothermal activity. Pyritic ejecta in ash-flow tuff are not reported in the literature, but there is no reason to believe that the Yucca Mountain occurrence is unique. The pyritic ejecta are considered by us to be part of a preexisting hydrothermal system that was partially or wholly destroyed during eruption of the tuff units. Because it was introduced as ejecta in tuff units that occur at depths of about 1,000 m, such pyrite does not constitute evidence of shallow mineralization at the proposed repository site; however, the pyrite may be evidence for mineralization deep beneath Yucca Mountain or as much as tens of kilometers from it

  15. THE INFLUENCE OF TEMPERATURE AND ADMIX- TURES ON ACTIVATION OF LOW CALCIUM FLY ASH

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    According to composition and structure properties of low calcium fly ash, the activation and reaction degree of fly ash-lime and fly ash-lime-gypsum system were studied in different alkali surroundings and temperatures by thermal-gravity analysis.The degree of reaction and pore structure analysis test results show that composite alkali play an important role in the activation and degree of reaction of fly ash at room temperature. But when increasing curing temperature, gypsum would play an important role in activation and hydration of fly ash.

  16. The enormous Chillos Valley Lahar: An ash-flow-generated debris flow from Cotopaxi Volcano, Ecuador

    Science.gov (United States)

    Mothes, P.A.; Hall, M.L.; Janda, R.J.

    1998-01-01

    The Chillos Valley Lahar (CVL), the largest Holocene debris flow in area and volume as yet recognized in the northern Andes, formed on Cotopaxi volcano's north and northeast slopes and descended river systems that took it 326 km north-northwest to the Pacific Ocean and 130+ km east into the Amazon basin. In the Chillos Valley, 40 km downstream from the volcano, depths of 80-160 m and valley cross sections up to 337000m2 are observed, implying peak flow discharges of 2.6-6.0 million m3/s. The overall volume of the CVL is estimated to be ???3.8 km3. The CVL was generated approximately 4500 years BP by a rhyolitic ash flow that followed a small sector collapse on the north and northeast sides of Cotopaxi, which melted part of the volcano's icecap and transformed rapidly into the debris flow. The ash flow and resulting CVL have identical components, except for foreign fragments picked up along the flow path. Juvenile materials, including vitric ash, crystals, and pumice, comprise 80-90% of the lahar's deposit, whereas rhyolitic, dacitic, and andesitic lithics make up the remainder. The sand-size fraction and the 2- to 10-mm fraction together dominate the deposit, constituting ???63 and ???15 wt.% of the matrix, respectively, whereas the silt-size fraction averages less than ???10 wt.% and the clay-size fraction less than 0.5 wt.%. Along the 326-km runout, these particle-size fractions vary little, as does the sorting coefficient (average = 2.6). There is no tendency toward grading or improved sorting. Limited bulking is recognized. The CVL was an enormous non-cohesive debris flow, notable for its ash-flow origin and immense volume and peak discharge which gave it characteristics and a behavior akin to large cohesive mudflows. Significantly, then, ash-flow-generated debris flows can also achieve large volumes and cover great areas; thus, they can conceivably affect large populated regions far from their source. Especially dangerous, therefore, are snowclad volcanoes

  17. HCl uptake by volcanic ash in the high temperature eruption plume: mechanistic insights

    Science.gov (United States)

    Ayris, P. M.; Delmelle, P.; Cimarelli, C.; Maters, E. C.; Suzuki, Y.; Dingwell, D. B.

    2014-12-01

    The injection of HCl into the stratosphere by large volcanic eruptions is considered to be little importance, due to the efficient incorporation of the former into hydrometeors within the cooling plume. However, HCl is also adsorbed onto ash surfaces to form soluble -Cl salts within the high temperature core of the eruption plume, and the atmospheric and environmental significance of this process is uncertain. We investigate the capacity of volcanic glasses with tephrite, phonolite, dacite, and rhyolite compositions to adsorb HCl at temperatures of 200-800°C in the presence of SO2, CO2 and He. Experiments show that only tephrite and phonolite glasses are significantly reactive to HCl, exhibiting optimal uptake at 400-600°C. The primary reaction product formed during adsorption is NaCl, but Ca-, K-, Al- and Fe- chlorides are also identified. Uptake of HCl by glass surfaces is sustained by interdiffusion of Na+ and other Cl-reactive cations with H+. Diffusion coefficient calculations yield Na diffusion coefficients for the four glasses, suggesting that the structural role for Na within the glass network governs the capacity for HCl retention. The uptake of HCl under experimental conditions is limited above 500°C by a Cl-induced dehydroxylation process, but the presence of H2O in the hydrous eruption plume may sustain or enhance adsorption. The experimental data, combined with simulated plume cooling profiles, suggest that HCl adsorption can be a significant scavenging mechanism in large explosive eruptions, particularly in peralkaline systems. The fate of adsorbed HCl is variable; some may be retained on ash surfaces within pyroclastic flows, while chloride-coated ash in the stratosphere could promote the formation of reactive Cl species associated with O3 destruction. Additionally, Fe- and Cl-bearing salts emplaced on ash surfaces by HCl adsorption within the plume cores of large explosive eruptions may increase the ocean fertilising potential of such events.

  18. Pneumatic testing in 45-degree-inclined boreholes in ash-flow tuff near Superior, Arizona

    International Nuclear Information System (INIS)

    Matrix permeability values determined by single-hole pneumatic testing in nonfractured ash-flow tuff ranged from 5.1 to 20.3 * 1046 m2 (meters squared), depending on the gas-injection rate and analysis method used. Results from the single-hole tests showed several significant correlations between permeability and injection rate and between permeability and test order. Fracture permeability values determined by cross-hole pneumatic testing in fractured ash-flow tuff ranged from 0.81 to 3.49 * 1044 m2, depending on injection rate and analysis method used. Results from the cross-hole tests monitor intervals showed no significant correlation between permeability and injection rate; however, results from the injection interval showed a significant correlation between injection rate and permeability. Porosity estimates from the 'cross-hole testing range from 0.8 to 2.0 percent. The maximum temperature change associated with the pneumatic testing was 1.2'(2 measured in the injection interval during cross-hole testing. The maximum temperature change in the guard and monitor intervals was O.Ip C. The maximum error introduced into the permeability values due to temperature fluctuations is approximately 4 percent. Data from temperature monitoring in the borehole indicated a positive correlation between the temperature decrease in the injection interval during recovery testing and the gas-injection rate. The thermocouple psychrometers indicated that water vapor was condensing in the boreholes during testing. The psychrometers in the guard and monitor intervals detected the drier injected gas as an increase in the dry bulb reading. The relative humidity in the test intervals was always higher than the upper measurement limit of the psychrometers. Although the installation of the packer system may have altered the water balance of the borehole, the gas-injection testing resulted in minimal or no changes in the borehole relative humidity

  19. Effect of Carbonization Temperature on Wear Rate Behaviour of Rice Husk Ash Reinforced Epoxy Composites

    OpenAIRE

    Francis Uchenna OZIOKO

    2012-01-01

    The effect of carbonization temperatures on wear rate behaviours of different volume fractions of rice husk ash epoxy composite was studied. Rice husk ash carbonized at 850, 900, and 950°C were reinforced in epoxy resin. Rice husk ash epoxy composite containing 10%, 20%, 30% and 40% rice husk ash was synthesized using manual stirring method and specimens were prepared for wear studies. Dry wear behaviour of sample was studied against abrasive paper using a pin-on-disc machine. Wear rate and s...

  20. Properties of municipal solid waste incineration ashes with respect to their separation temperature

    Czech Academy of Sciences Publication Activity Database

    Keppert, M.; Pavlík, Z.; Tydlitát, V.; Volfová, P.; Švarcová, Silvie; Šyc, Michal; Černý, R.

    2012-01-01

    Roč. 30, č. 10 (2012), s. 1041-1048. ISSN 0734-242X Institutional support: RVO:61388980 ; RVO:67985858 Keywords : bottom ash * fly ash * municipal solid waste incinerator * pozzolanic activity * hydration heat * separation temperature * building industry Subject RIV: CA - Inorganic Chemistry Impact factor: 1.047, year: 2012

  1. Activation of fly ashes by the high temperature and high alkalinity in ASR tests

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    High temperature and high alkalinity are typical testing conditions to accelerate the appraisal process of the suppressing effect of fly ashes on alkali silica reaction(ASR),but the reaction mechanism of fly ashes would be quite different under such conditions compared to the normal condition of temperature and alkalinity.To make a reasonable analysis of the suppressing effect of fly ashes,13 types of fly ashes were tested in this paper by both the accelerated mortar bar test method and the 60°C accelerated concrete prism test method.The results showed that the effect of fly ashes would be magnified under the condition of high temperature and high alkalinity.The XRD analysis showed that all the phases of fly ash could react with the hot alkaline solution except for mullite and a small amount of quartz.Fly ash could be significantly activated by the 80°C 1 mol/L NaOH solution,and form mainly C-S-H phase and P type zeolite,but its effect on inhibiting ASR was exaggerated then.According to the mortar strength test and the ASR suppressing test results,C-S-H phase contributed to mortar strength,but its amount did not decide the ASR suppressing effect of fly ash.

  2. Synthesis and sintering of high-temperature composites based on mechanically activated fly ash

    Directory of Open Access Journals (Sweden)

    Terzić A.

    2012-01-01

    Full Text Available Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products. As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side. [Projekat Ministarstva nauke Republike Srbije, br. 172057, 45008 and a project F-198, financed by Serbian Academy of Sciences and Arts

  3. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    International Nuclear Information System (INIS)

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H

  4. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Deschner, Florian, E-mail: florian.deschner@gmail.com [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Lothenbach, Barbara; Winnefeld, Frank [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Neubauer, Jürgen [GeoZentrum Nordbayern, Mineralogy, University of Erlangen-Nuremberg, 91054 Erlangen (Germany)

    2013-10-15

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H.

  5. Modeling and Prediction of Coal Ash Fusion Temperature based on BP Neural Network

    Directory of Open Access Journals (Sweden)

    Miao Suzhen

    2016-01-01

    Full Text Available Coal ash is the residual generated from combustion of coal. The ash fusion temperature (AFT of coal gives detail information on the suitability of a coal source for gasification procedures, and specifically to which extent ash agglomeration or clinkering is likely to occur within the gasifier. To investigate the contribution of oxides in coal ash to AFT, data of coal ash chemical compositions and Softening Temperature (ST in different regions of China were collected in this work and a BP neural network model was established by XD-APC PLATFORM. In the BP model, the inputs were the ash compositions and the output was the ST. In addition, the ash fusion temperature prediction model was obtained by industrial data and the model was generalized by different industrial data. Compared to empirical formulas, the BP neural network obtained better results. By different tests, the best result and the best configurations for the model were obtained: hidden layer nodes of the BP network was setted as three, the component contents (SiO2, Al2O3, Fe2O3, CaO, MgO were used as inputs and ST was used as output of the model.

  6. Predicting coal ash fusion temperature based on its chemical composition using ACO-BP neural network

    International Nuclear Information System (INIS)

    Coal ash fusion temperature is important to boiler designers and operators of power plants. Fusion temperature is determined by the chemical composition of coal ash, however, their relationships are not precisely known. A novel neural network, ACO-BP neural network, is used to model coal ash fusion temperature based on its chemical composition. Ant colony optimization (ACO) is an ecological system algorithm, which draws its inspiration from the foraging behavior of real ants. A three-layer network is designed with 10 hidden nodes. The oxide contents consist of the inputs of the network and the fusion temperature is the output. Data on 80 typical Chinese coal ash samples were used for training and testing. Results show that ACO-BP neural network can obtain better performance compared with empirical formulas and BP neural network. The well-trained neural network can be used as a useful tool to predict coal ash fusion temperature according to the oxide contents of the coal ash

  7. Study of thermal-flow processes in ash cooler cooperating with CFB boiler

    Directory of Open Access Journals (Sweden)

    Paweł Regucki

    2016-03-01

    Full Text Available The article presents an example of thermal-flow analysis of the bottom ash cooler cooperating with the circulating fluidized bed boiler. There is presented a mathematical model of series-parallel hydraulic system supplying the ash cooler in cooling water. The numerical calculations indicate an influence of changes of the pipeline geometrical parameters on the cooling water flow rate in the system. Paper discusses the methodology of the studies and presents examples of the results of thermal balance calculations based on the results of measurements. The numerical results of the thermal-flow analysis in comparison with the measurements on the object indicate that the presented approach could be used as a diagnostic tool investigating the technical state of the bottom ash cooler.

  8. Multivariable Regression and Adaptive Neurofuzzy Inference System Predictions of Ash Fusion Temperatures Using Ash Chemical Composition of US Coals

    Directory of Open Access Journals (Sweden)

    Shahab Karimi

    2014-01-01

    Full Text Available In this study, the effects of ratios of dolomite, base/acid, silica, SiO2/Al2O3, and Fe2O3/CaO, base and acid oxides, and 11 oxides (SiO2, Al2O3, CaO, MgO, MnO, Na2O, K2O, Fe2O3, TiO2, P2O5, and SO3 on ash fusion temperatures for 1040 US coal samples from 12 states were evaluated using regression and adaptive neurofuzzy inference system (ANFIS methods. Different combinations of independent variables were examined to predict ash fusion temperatures in the multivariable procedure. The combination of the “11 oxides + (Base/Acid + Silica ratio” was the best predictor. Correlation coefficients (R2 of 0.891, 0.917, and 0.94 were achieved using nonlinear equations for the prediction of initial deformation temperature (IDT, softening temperature (ST, and fluid temperature (FT, respectively. The mentioned “best predictor” was used as input to the ANFIS system as well, and the correlation coefficients (R2 of the prediction were enhanced to 0.97, 0.98, and 0.99 for IDT, ST, and FT, respectively. The prediction precision that was achieved in this work exceeded that reported in previously published works.

  9. Behavior of Alkali Metals and Ash in a Low-Temperature Circulating Fluidized Bed (LTCFB) Gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk;

    2016-01-01

    W and a 6 MW LTCFBgasifier. Of the total fuel ash entering the system, the largest fraction (40−50%) was retained in the secondary cyclone bottoms,while a lower amount (8−10%) was released as dust in the exit gas. Most of the alkali and alkaline earth metals were retained inthe solid ash, along with Si......, the low reactor temperature ensures that high-alkali biomass fuels canbe used without risk of bed defluidization. This paper presents the first investigation of the fate of alkali metals and ash in lowtemperaturegasifiers. Measurements on bed material and product gas dust samples were made on a 100 k...

  10. Properties of municipal solid waste incineration ashes with respect to their separation temperature.

    Science.gov (United States)

    Keppert, Martin; Pavlík, Zbysek; Tydlitát, Vratislav; Volfová, Petra; Svarcová, Silvie; Syc, Michal; Cerny, Robert

    2012-10-01

    Fly ashes generated by power and heating plants are commonly used in the production of building materials in some countries, mainly as partial replacement of cement or aggregates in concrete. The ashes from municipal solid waste incinerators can be applied in a similar way. However, their chemical and mineralogical composition, granulometry and toxic constituents have to be taken into account. In this paper, four types of municipal solid waste incinerator (MSWI) ashes produced by the modern MSWI facility in Liberec, Czech Republic, were investigated. The relationship between the particular ash properties (morphology, chemical composition) and its separation temperature in the incinerator line is discussed. A coal fly ash (class F) is characterized as well, for a comparison because its utilization in building industry is more developed. The studied MSWI ashes exhibit high concentration of chlorides and sulfates which is an unfavourable feature for a potential concrete admixture. On the other hand, three of four ashes are found to be pozzolanic active and certain hydration reactions are indicated. PMID:22677916

  11. High temperature corrosion of boiler steels in hydrochloric atmosphere under oil shale ashes

    International Nuclear Information System (INIS)

    Highlights: • High temperature gaseous hydrochloric corrosion analysis of different boiler steels. • Influence on the corrosion of the presence of oil shale ashes and cyclic removing. • Empiric kinetic coherence equation and diagram for corrosion depth versus time. • Additional oxidation tests of all materials investigated. • Qualitative analysis of the present corrosion mechanisms. - Abstract: High temperature corrosion in power plants is a main breakdown criterion in boiler applications. This study is focused on the high-temperature corrosion resistance of several boiler steels used in Estonian power plants, which were experimentally tested in gaseous hydrochloric environment combined with Estonian oil shale ashes in a high temperature corrosion test up to 600 °C. Scanning electron microscopy supported by energy dispersive X-ray spectroscopy was used to reveal different corrosion mechanisms. Results indicate a strong dependence of the boiler steel corrosion to the present anions in the oil shale ash and their removal in the boiler

  12. Coal and char properties in high temperature entrained flow gasification

    International Nuclear Information System (INIS)

    With the objective to measure coal conversion at realistic operation conditions the Pressurised High Temperature Entrained Flow Reactor (PiTER) is developed. The pyrolysis of Rhenish lignite is studied at temperatures up to 1600 °C and pressures up to 2.5 MPa. At longer residence time (above 1.5 s) volatile yield is 68 wt% and independent of temperature and pressure. Char samples are extracted from the hot reaction zone and their reactivity is analysed by weight loss in TGA experiments at defined conditions. Furthermore, specific char surface area is measured. At 1200 °C the intrinsic reactivity of char decreases by a factor of almost 7 from 0.5 s to 2 s residence time, but surface area (approximately 500 m2/g) is hardly affected. At 1400 °C and 1600 °C, the intrinsic reactivity also decreases, but simultaneously the surface area is reduced to below 300 m2/g. The difference in deactivation can only be explained by two different mechanisms: (i) experiments at 1200 °C are below the ash fusion temperature and graphitisation at the char surface may lead to a reorganisation of carbon atoms; (ii) above the ash fusion temperature, the melting of mineral matter additionally blocks the micropore structure and results in a loss of specific surface area. -- Highlights: ► Development of a novel pilot scale entrained flow research reactor. ► Pyrolysis at up to 1600 °C and up to 2.5 MPa under entrained flow conditions. ► Surface area of char significantly decreases above the ash melting temperature. ► Intrinsic reactivity of char is dependent on heat treatment severity. ► Thermal annealing affects char reactivity, even at short residence time.

  13. Tensile strength of ash cake beds at high-temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dockter, B.A.; Hurley, J.P.

    1996-12-31

    The Energy and Environmental Research Center (EERC) is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The primary deliverable will be a graphics-driven computer model that can be used as an engineering tool to help predict ash-related hot-gas filter problems based on analyses of coal and sorbent, as well as system operating parameters. This paper presents preliminary testing data on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions. The range in temperatures for tensile testing is ambient to 900 C. The simulated gas atmosphere includes carbon dioxide, water vapor, oxygen, sulfur dioxide, sodium chloride, hydrochloric acid, and nitrogen. At present, all testing has been performed using ash from the Westinghouse advanced particle filter (APF) at the American Electric Power Service Corporation (AEP) Tidd pressurized fluidized-bed combustor (PFBC) demonstration plant in Ohio. Other sources of filter ashes, including several from non-American PFBC systems, will also be evaluated.

  14. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    Science.gov (United States)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  15. The use of magnetic susceptibility and its frequency dependence for delineation of a magnetic stratigraphy in ash-flow tuffs

    International Nuclear Information System (INIS)

    Variations in the grain size, amount, and mineralogy of magnetic phases in layered volcanic rocks define a magnetic stratigraphy that can be identified by means of magnetic susceptibility measurements. In ash-flow tuffs, grain size and other variables that control susceptibility are to a large extent a function of the cooling and alteration history. The phases responsible for the susceptibility of ash-flow tuffs consist of post-emplacement high-temperature precipitates of Fe-oxides in volcanic glass, and the phenocrystic Fe-Ti oxides. At Yucca Mountain, Nevada, laterally-continuous high-susceptibility (∼ 10-2 SI) horizons exist in the Paintbrush Tuff due to the presence of either precipitates or phenocrystic Fe-Ti oxides. The frequency dependence of magnetic susceptibility, χ(ω), can be used to discriminate between horizons with multi-domain phenocrystic material. The χ(ω) exhibits a 26% decrease per decade of increasing frequency for precipitate grain sizes where the superparamagnetic single-domain state gives way to stable single-domain behavior, and thus χ(ω) offers an indirect method for rapid estimation of magnetic grain sizes. The interpretation of variations established by field and laboratory susceptibility data has been constrained by petrography and transmission electron microscopy (TEM)

  16. Flow behaviour and drag reduction of fluidic ash-water slurries

    Czech Academy of Sciences Publication Activity Database

    Vlasák, Pavel; Chára, Zdeněk

    Johannesburg : The S.A. Institute of Mining and Metallurgy and BHR Group, 2007, s. 39-55. ISBN 978-1-85598-084-6. - (Symposium Series. S 46). [HYDROTRANSPORT: International Conference on the Hydraulic Transport of Solids /17./. Cape Town (ZA), 08.05.2007-10.05.2007] R&D Projects: GA AV ČR IAA200600503 Institutional research plan: CEZ:AV0Z20600510 Keywords : fluidic ash slurry * laminar flow * turbulent flow * laminar/turbulent transition * drag reduction Subject RIV: BK - Fluid Dynamics

  17. Effect of incineration temperature on phosphorus availability in bio-ash from manure.

    Science.gov (United States)

    Thygesen, A M; Wernberg, O; Skou, E; Sommer, S G

    2011-04-01

    In the near future phosphorus (P) will be a limited resource in high demand. This will increase the incentives for recycling P in animal manure. In this study the dry-matter-rich fraction from slurry separation was incinerated and the P availability of the ash fraction examined. The aim was to adjust incineration temperature to support a high plant-availability of P in ash. The plant-availability of P was approximately halved when the incineration temperature was increased from 400 to 700 degrees C. This decrease in plant-availability was probably due to the formation of hydroxyapatite. Incineration temperatures should therefore be kept below 700 degrees C to ensure a high fertilizer efficiency of P in ash. This may conflict with the energy production, which is optimal at temperatures above 800 degrees C. An alternative to incineration may therefore be thermal gasification of the dry-matter-rich fraction, which can be carried out efficiently at lower temperatures. PMID:21877544

  18. Effects of fire temperature on the physical and chemical characteristics of the ash from two plots of Cork oak (Quercus Suber)

    Science.gov (United States)

    Ubeda, X.; Pereira, P.; Outeiro, L.; Martin, D.A.

    2009-01-01

    also showed that for the same temperature, a higher severity results for Albufeira litter. Potential negative effects on soil properties are observed at medium and higher temperatures. These negative effects include a higher percentage of mass loss, meaning more soil may be exposed to erosion, higher pH values and greater cation release from ash, especially monovalalent cations (K+,Na+) in higher proportions than the divalent ions (Ca2+, Mg2+), that can lead to impacts on soil physical properties like aggregate stability. Furthermore, the ions in ash may alter soil chemistry which may be detrimental to some plants thus altering the recovery of these ecosystems after fire. Low intensity prescribed fire can be a useful tool to land management in these sites, due to the reduced effects of fire temperatures on the physical and chemical properties of surface litter, and can reduce the risk of high temperature wildland fires by reducing fuel loadings. From the perspective of water resources, lower fire temperatures produce fewer impacts on the chemistry of overland flow and there is less probability that the soil surface will be eroded. Copyright ?? 2009 John Wiley & Sons, Ltd.

  19. Manipulation of gasification coal feed in order to increase the ash fusion temperature of the coal to operate the gasifiers at higher temperatures / Johannes Chrisstoffel van Dyk

    OpenAIRE

    Van Dyk, Johannes Chrisstoffel

    2006-01-01

    Coal is a crucial feedstock for South Africa's unique synfuels and petrochemicals industry and used by Sasol as a feedstock to produce synthesis gas via the Sasol-Lurgi Fixed Bed Dry Bottom (FBDB) gasification process. The ash fusion temperature (AFT) gives detail information on the suitability of a coal source for gasification purposes, and specifically to the extent ash agglomeration or clinkering is likely to occur within the gasifier. Ash clinkering inside the gasifier can cause channel b...

  20. Dust separation at high temperatures a method for cleaning fly ashes? Final report; Stoftavskiljning vid hoeg temperatur en metod foer rening av flygaska? Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Zintl, Frank [TPS Termiska Processer AB, Nykoeping (Sweden)

    2002-12-01

    An experimental study of separation of fly ashes by a filter at high temperatures, 300-650 deg C, with the purpose to study: Capture of heavy metals (Cd, Hg, Pb, Zn) in the fly ash; Relation between heavy metal capture and temperature; Relation between heavy metal capture and the availability of fuel chlorine. Pelletized forestry waste fuel was doped with heavy metals in two different forms. Pelletized Salix was also used, without doping. The study shows that: There is a strong inverse relation between the capture of heavy metals and the filter temperature; There is a strong relation between the availability of chlorine and the capture of heavy metals. Separation at 300-650 deg C gives much less heavy metals in the fly ash, however the ash is not clean enough to allow disposal in ordinary landfills. Thus, high temperature filtering does not seem to be a promising solution for producing 'clean' fly ash.

  1. Losses of arsenic during the low temperature ashing of atmospheric particulate samples

    International Nuclear Information System (INIS)

    Neutron activation and atomic absorption procedures have been used to study arsenic losses during low temperature ashing at power levels between 50 and 125 watts (RF). Losses of arsenic from ambient atmospheric particulate matter and various synthetic sea salt matrices containing known quantities of arsenic was observed. In general, the magnitude of arsenic losses by this treatment will depend on applied power levels and the physical and chemical properties of the arsenic sample matrix

  2. Time Series Measurements of Diffuse Hydrothermal Flow at the ASHES Vent Field Reveal Tidally Modulated Heat and Volume Flux

    Science.gov (United States)

    Mittelstaedt, E. L.; Fornari, D. J.; Crone, T. J.

    2015-12-01

    Existing time-series measurements of temperature and velocity of diffuse hydrothermal fluids exhibit variability over a range of periods from seconds to days. Frequency analysis of these measurements reveals differences between studies and field locations including nearly white spectra, as well as spectra with peaks at tidal and inertial periods. Based upon these results, previous authors have suggested several processes that may control diffuse flow rates, including tidally induced currents and 'tidal pumping', and have also suggested that there are no systematic controls. To further investigate the processes that control variability in diffuse flow, we use data from a new, deep-sea camera and temperature measurement system, the Diffuse Effluent Measurement System (DEMS), deployed during the July, 2014 cruise of the R/V Atlantis. The DEMS was deployed with DSV Alvin above a fracture network at the Phoenix vent within the ASHES vent field (Axial Seamount, 1541 mbsl). The system collected 20 seconds of imagery at 20 Hz and 24 seconds of temperature measurements at 1 Hz each hour over the period between July 22 and August 2nd. Velocities of the upwelling fluids were calculated using Diffuse Fluid Velocimetry (DFV; Mittelstaedt et al., 2010). DFV is a cross correlation technique that tracks moving index of refraction anomalies (i.e., hot parcels of fluid) through time. Over the ~12 day deployment, median flow rates ranged from 0.5 cm/s to 6 cm/s and mean fluid temperature anomalies from 0°C up to ~6.5°C, yielding an average heat flux density of 0.23 MW/m2. Spectral analysis of both the measured temperatures and calculated velocities yield a peak in normalized power at the semi-diurnal lunar period (M2, 12.4hrs), but no other spectral peaks above the 95% confidence level. Here, we present these results and discuss their implications for the tidal current and tidal pressure models of diffuse flow variability at the ASHES vent field.

  3. Development of sodium/lithium/fly ash sorbents for high temperature post-combustion CO2 capture

    International Nuclear Information System (INIS)

    Highlights: • Fly ash (FA) based Na/Li silicates for high temperature CO2 capture were developed. • Li–Na–FA molar ratios and calcination temperature determined the sorbents CO2 uptake. • CO2 uptake capacity was 2.54 mol CO2/kg sorbent with 12% H2O and 14% CO2 at 700 °C. • Na/Li–FA sorbents maintained their capacity and adsorption/desorption rates after 21 cycles. - Abstract: CO2 capture from combustion processes faces several challenges including high energy penalty, low CO2 partial pressure, high flow rates and presence of water vapours. Absorption of CO2 at high temperature is recently attracting increasingly attention. Alkali metal based sorbents present clear advantages compared to other high temperature sorbents, such as high CO2 capture capacity, lower regeneration temperatures (<750 °C) and excellent stability. In this work, Na/Li-silicates prepared by mixing Na/Li carbonates with fly ash (FA) in various molar ratios were evaluated for their capacity to chemisorb CO2 at 500–700 °C and in presence of H2O (2–12 vol%), diluted CO2 (14 vol%) and CO2 sorption promoters. The results indicate that the carbonate:silica ratio used in the sorbents synthesis significantly affects the CO2 sorption capacity and regeneration temperature. The presence of steam enhances the diffusion of Li and Na ions resulting in higher CO2 uptake. CO2 chemisorption follows a double layer mechanism with formation of carbonate layer on the surface. The simultaneous presence of Li and Na (and K when used as additive) in the formed carbonate layer results in an eutectic melt between 600 and 700 °C, which facilitates the diffusion of the ionic species. Li–Na–FA with molar ratio of 0.5:0.5:1 was the best prepared sorbent with a capacity of 2.54 mol CO2/kg sorbent (12% H2O, 14% CO2 at 700 °C). Absorption/desorption was completed in 15 min with reaction kinetics comparable to that of pure Li4SiO4 sorbents. The tested materials maintained their capacity and absorption

  4. Thermal behaviour of geopolymers prepared using class F fly ash and elevated temperature curing

    Energy Technology Data Exchange (ETDEWEB)

    T. Bakharev [Monash University, Clayton, Vic. (Australia). Department of Civil Engineering

    2006-06-15

    This article reports a study of thermal stability of properties upon firing at 800-1200{sup o}C of geopolymer materials prepared using class F fly ash and Na and K alkaline activators. Compressive strength and shrinkage measurements, XRD, SEM (BEI), TGA and MIP were utilised in these studies. The materials were prepared at water/binder ratios in a range of 0.09-0.35, using compaction pressures up to 10 MPa and curing temperatures 80 and 100{sup o}C. Thermal stability of the studied geopolymer materials was rather low. In the samples prepared using sodium-containing activators rapid deterioration of strength at 800{sup o}C was observed, which was connected to a dramatic increase of the average pore size. Initially amorphous structures were replaced by the crystalline Na-feldspars. In materials prepared using fly ash and potassium silicate compressive strength was significantly increased on heating, deterioration of strength started at 1000{sup o}C. After firing these materials remained amorphous with reduced average pore size and significantly increased compressive strength. Compaction at 1-10 MPa reduced shrinkage on firing in all materials. Geopolymer materials prepared using class F fly ash and alkaline activators showed high shrinkage as well as large changes in compressive strength with increasing fired temperature in the range of 800-1200{sup o}C. Thus the materials were found unsuitable for refractory insulation applications.

  5. Ash deposition and high temperature corrosion at combustion of aggressive fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hede Larsen, O. [I/S Fynsvaerket, Faelleskemikerne, Odense (Denmark); Henriksen, N. [Elsamprojekt A/S, Faelleskemikerne, Fredericia (Denmark)

    1996-12-01

    In order to reduce CO{sub 2} emission, ELSAM is investigating the possibilities of using biomass - mainly straw - for combustion in high efficiency power plants. As straw has very high contents of chlorine and potassium, a fuel with high corrosion and ash deposition propensities has been introduced. ELSAM has investigated 3 ultra supercritical boiler concepts for combustion of straw alone or together with coal: (1) PF boilers with a relatively low share of straw, (2) CFB boilers with low to high share of straw and (3) vibrating grate boilers with 100% straw. These investigations has mainly been full-scale tests with straw fed into existing boilers. Corrosion tests have been performed in these boilers using temperature regulated probes and in-plant test tubes in existing superheaters. The corrosion has been determined by detailed measurements of wall thickness reduction and light optical microscopic measurements of the material degradation due to high temperature corrosion. Corrosion mechanisms have been evaluated using SEM/EDX together with thermodynamical considerations based on measurements of the chemical environment in the flue gas. Ash deposition is problematic in CFB boilers and in straw fired boilers, especially in years with high potassium and chlorine content of the straw. This ash deposition also is related to condensation of KCl and can probably only be handled by improved cleaning devices. (EG)

  6. Petrochemistry of coal ash slags. I. Formation of melilite and a high temperature glass from a calcium-rich, silica-deficient slag

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.; Barbie, D.L.; Christensen, O.D.; Kerner, F.R.

    1977-01-01

    Pilot plant studies are being conducted of a fixed-bed slagging coal gasification process. Lignite from the Indianhead mine is reacted with steam and oxygen in a gasifier at hearth zone temperatures over 1650/sup 0/C. Slag samples were subjected to chemical and petrographic analysis. Layers of layered slag modules were analyzed; the inner layers contain abundant melilite while the outer core is a glass. Results show that the characteristics of the coal ash slag can be affected by temperature fluctuations in the gasifier hearth, and that chemical, flow, and heat transfer behavior are all susceptible to change as a result. 8 figs., 3 tables. (DLC)

  7. Peculiar high temperature corrosion of martensite alloy under impact of Estonian oil shale fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Tallermo, H.; Klevtsov, I. [Thermal Engineering Department of Tallinn Technical University, Tallinn (Estonia)

    1998-12-31

    The superheaters` surfaces of oil shale steam boiler made of pearlitic and austenitic alloys, are subject to intensive corrosion, mainly due to presence of chlorine in external deposits. The applicability of martensitic alloys X1OCrMoVNb91 and X20CrMoV121 for superheaters is examined here and empirical equations allowing to predict alloys` corrosion resistance in the range of operational temperatures are established. Alloy X1OCrMoVNb91 is found been most perspective for superheaters of boilers firing fossil fuel that contain alkaline metals and chlorine. The abnormal dependence of corrosion resistance of martensitic alloys on temperature is revealed, namely, corrosion at 580 deg C in presence of oil shale fly ash is more intensive than at 620 deg C. (orig.) 2 refs.

  8. High temperature capture of CO2 on lithium-based sorbents from rice husk ash

    International Nuclear Information System (INIS)

    Highly efficient Li4SiO4 (lithium orthosilicate)-based sorbents for CO2 capture at high temperature, was developed using waste materials (rice husk ash). Two treated rice husk ash (RHA) samples (RHA1 and RHA2) were prepared and calcined at 800 oC in the presence of Li2CO3. Pure Li4SiO4 and RHA-based sorbents were characterized by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetry. CO2 sorption was tested through 15 carbonation/calcination cycles in a fixed bed reactor. The metals of RHA were doped with Li4SiO4 resulting to inhibited growth of the particles and increased pore volume and surface area. Thermal analyses indicated a much better CO2 absorption in Li4SiO4-based sorbent prepared from RHA1 (higher metal content sample) because the activation energies for the chemisorption process and diffusion process were smaller than that of pure Li4SiO4. RHA1-based sorbent also maintained higher capacities during the multiple cycles.

  9. GIS-based statistical mapping technique for block-and-ash pyroclastic flow and surge hazards

    Science.gov (United States)

    Widiwijayanti, C.; Voight, B.; Hidayat, D.; Schilling, S.

    2008-12-01

    Assessments of pyroclastic flow (PF) hazards are commonly based on mapping of PF and surge deposits and estimations of inundation limits, and/or computer models of varying degrees of sophistication. In volcanic crises a PF hazard map may be sorely needed, but limited time, exposures, or safety aspects may preclude fieldwork, and insufficient time or baseline data may be available for reliable dynamic simulations. We have developed a statistically constrained simulation model for block-and-ash PFs to estimate potential areas of inundation by adapting methodology from Iverson et al. (1998) for lahars. The predictive equations for block-and-ash PFs are calibrated with data from many volcanoes and given by A = (0.05-0.1)V2/3, B = (35-40)V2/3 , where A is cross-sectional area of inundation, B is planimetric area and V is deposit volume. The proportionality coefficients were obtained from regression analyses and comparison of simulations to mapped deposits. The method embeds the predictive equations in a GIS program coupled with DEM topography, using the LAHARZ program of Schilling (1998). Although the method is objective and reproducible, any PF hazard zone so computed should be considered as an approximate guide only, due to uncertainties on coefficients applicable to individual PFs, DEM details, and release volumes. Gradational nested hazard maps produced by these simulations reflect in a sense these uncertainties. The model does not explicitly consider dynamic behavior, which can be important. Surge impacts must be extended beyond PF hazard zones and we have explored several approaches to do this. The method has been used to supply PF hazard maps in two crises: Merapi 2006; and Montserrat 2006- 2007. We have also compared our hazard maps to actual recent PF deposits and to maps generated by several other model techniques.

  10. Leaching of biomass from semi-natural grasslands – Effects on chemical composition and ash high-temperature behaviour

    International Nuclear Information System (INIS)

    Combustion of biodiversity-rich semi-natural grassland biomass no longer needed for forage allows nature conservation to be combined with bioenergy production. Natural leaching by rainfall during the period between biomass harvest and collection can reduce the content of elements detrimental for the combustion of grassland biomass. This study assesses the influence of biomass characteristics on leaching efficiency and the potential effects of leaching on ash melting behaviour and elemental release. Grassland biomass harvested from five sites at two harvest dates was leached at two intensities. Low-temperature ash was heated to 700, 800, 900 and 1000 °C respectively and classified into four ash fusion classes. Ash mass loss was determined as a measure of high-temperature elemental release. Weather data were used to calculate the frequency of weather conditions favourable to on-field leaching. K and Cl were leached most strongly and were reduced by 30 and 45% respectively by a leaching treatment corresponding to 30–40 mm of rain. The effects of site and harvest date on leaching efficiency were significant but small. Ash melting behaviour and elemental release between 700 and 900 °C were favourably influenced by leaching. The K/(Ca + Mg) and Si/ash ratios were related to increased ash melting. In this respect, semi-natural grassland biomass differs from other, less Ca-rich, herbaceous biofuels. Even if suitable weather conditions are not occurring frequently at the study sites, on-field leaching can offer an additional low-cost, on-farm strategy option for farmers and nature conservation agencies to improve biomass quality of nature conservation grasslands for combustion. -- Graphical abstract: Highlights: ► Combustion of biomass from biodiversity-rich nature conservation grassland. ► Leaching by rain during the field period reduces K and Cl concentrations. ► Increasing K/(Ca + Mg) and decreasing (K + Ca + Mg)/ash ratios increase ash melting. ► Leaching

  11. Determination and statistical evaluation of the effect of minerals and mineral associations in specific dense medium fractions on ash fusion temperature / Ashriti Govender

    OpenAIRE

    Govender, Ashriti

    2005-01-01

    During Sasol-Lurgi Fixed Bed Dry Bottom coal gasification, the mineral matter in coal undergoes various transformations. Heat induced transformation due to low ash fusion temperatures leads to agglomeration of the ash particles to sizes varying from tiny particles to lumps larger than 100mm. Channel burning and instability in the ash bed can occur as a result. It is therefore important to understand and anticipate the reactions of the mineral matter prior to feeding the coal...

  12. Measurement of temperature conditions in grate zone of a 1 MW wood-pellets boiler fired with high ash content wood-pellets

    OpenAIRE

    Skotland, Christer Heen

    2009-01-01

    The combustion of biomass could in some cases lead to ash problems induced by high temperatures such as ash sintering, agglomeration and melting. The degrees of these problems depend on the fuel feedstock and are highly dependent on the amount of potassium, sodium and chlorine in the biomass. Straw, grass, bark, branches and wood residues are typical examples of biomass fuels that are connected to the mentioned ash problems.Addition of additives in the problematic fuels is a possible measure ...

  13. Epizonal I- and A-type granites and associated ash-flow tuffs, Fogo Island, northeast Newfoundland

    OpenAIRE

    Malpas, J.; Sandeman, HA

    1995-01-01

    Magmatic activity of Silurian-Devonian age is widespread in the Appalachian-Caledonian Orogen. A marked characteristic of this magmatism is the composite nature of the igneous suites, which range from peridotite to granodiorite in single plutonic bodies. Such a suite of intrusive rocks, ranging in composition from minor peridotite to granodiorite, intrudes an openly folded sequence of Silurian volcanogenic sandstones and ash-flow tuffs on Fogo Island, northeast Newfoundland. Two units, the Ro...

  14. Effects of ash forming temperature on water-soluble fraction of biomass ash and it’s elements%成灰温度对三种生物质灰及其元素水溶性的影响

    Institute of Scientific and Technical Information of China (English)

    何芳; 于如军; 张毅; 朱继英; 高振强; 孙鹏

    2015-01-01

    生物质灰及灰中化学元素的水溶特性是其是否能作为肥料应用的主要指标,成灰温度会影响这些特性。该文试验研究了成灰温度在400~800℃范围内,3种主要农业废弃物麦秸、玉米秸、稻壳的灰的水溶性和灰中各元素的水溶性。结果表明:1)麦秸灰、玉米秸灰的水溶性明显高于稻壳灰,三者水溶性都随成灰温度增高而显著降低,温度从400升高到800℃,水溶性分别从48%,35%和12%降至约12%,8%和0。2)灰中水溶元素主要有K,Cl和S,其中,K和Cl的水溶性随着成灰温度升高而降低,而S的水溶性几乎不受成灰温度的影响。%The implementation of biomass ash as a fertilizer is beneficial to the sustainable development of agriculture because it can return the elements taken by the plants from soil during the growth. Water solubility of biomass ash together with its elements is a vital property for the fertilizer’s utilization. In this paper, the effects of ash forming temperature on the water solubility of biomass ash and its elements were investigated experimentally. Three typical types of agro-residues in China, i.e. wheat straw, corn stover and rice husk, were chosen for investigation. Materials were collected and the corresponding proximate and elemental analyses were performed. In preparation process, wheat straw and corn stover were milled into powder with the particle size of less than 1 mm. Ashes were prepared in a muffle furnace at different ash forming temperatures in the scope from 400 to 800℃with the temperature interval of 50℃. About 4-5 g of each sample powder and rice husk were put in the crucibles, heated from ambient temperature to ash forming temperature, and then kept at the ash forming temperature for 4 hours in the muffle furnace. After the temperature of the furnace dropped to less than 200℃, the ashes were taken out to the cabinet dryer, cooled to the ambient temperature, and then

  15. Hydrothermal Synthesis of Zeolite from Coal Class F Fly Ash. Influence of Temperature

    Directory of Open Access Journals (Sweden)

    Goñi, S.

    2010-06-01

    Full Text Available The influence of temperature of alkaline hydrothermal treatment on the conversion in zeolite of Spanish coal low calcium-fly ash (ASTM class F is presented in this work. Zeolite Na-P1 gismondine type (Na6Al6Si10O32.12H2O was formed at the temperature of 100ºC, which transformed in zeolite; analcime-C type (Na(Si2AlO6H2O and sodalite (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O at 200ºC together with traces of tobermorite-11Å (Ca5(OH2Si6O16.4H2O. At this temperature the 100% of the fly ash reaction was allowed. An equivalent study was carried out in water as reference. The zeolite conversion of the fly ash was characterized by X ray diffraction (XRD, FT infrared (FTIR spectroscopy, surface area (BET-N2 and thermal analyses.

    En este trabajo se presenta el papel que juega la temperatura durante el tratamiento hidrotermal en medio alcalino para convertir una ceniza volante de bajo contenido en cal (clase F, según la norma ASTM en zeolita. Durante este tratamiento a la temperatura de 100ºC se forma Zeolita Na-P1 tipo gismondina (Na6Al6Si10O32.12H2O; al elevar la temperatura a 200ºC, dicha zeolita se transforma en zeolita Analcima C (Na(Si2AlO6H2O y en fase sodalita (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O junto con trazas de tobermorita-11Å (Ca5(OH2Si6O16.4H2O. A esta temperatura y en estas condiciones se ha conseguido un 100% de reacción. Un estudio equivalente se ha llevado a cabo empleando agua como medio de referencia. La conversión de ceniza volante en zeolita se ha caracterizado mediante técnicas, como difracción de Rayos X (DRX, espectroscopia

  16. Sintesis ZSM-5 dari Fly Ash Sawit Sebagai Sumber Silika dengan Variasi Nisbah Molar Si/Al dan Temperatur Sintesis

    Directory of Open Access Journals (Sweden)

    Ida Zahrina

    2012-12-01

    Full Text Available Palm fly ash is biomass/waste in the  palm oil industry. Palm fly ash has high content of amorphous silica. ZSM-5 is one of synthetic zeolite which is widely used as catalyst in industries. ZSM-5 has high activity and selectivity to several hydrocarbon conversion reaction. Hence, ZSM-5 is being investigated for the conversion of vegetable oil to hydrocarbon.  It can be synthesized from silica and alumina. Sources of silica that can be added to the ZSM-5 synthesis,  are sodium silicate, hydrated silica, water glass sol silica, gelled silica, clay, precipitated silicaand calcined silica. ZSM-5 was synthesized free-template by using palm fly ash as silica source. In this research synthesis of ZSM-5 was carried out in autoclave at 18 hours and Na2O/Al2O3 molar ratio by various molar ratio from 30 to 40 and temperature in the range of 150 to 190 oC. The product was then analized using FTIR method. The best ZSM-5 product was obtained at Si/Al molar ratio of 40 and process temperature of 150 oC. Keywords: FTIR, Palm fly ash, ZSM-5

  17. Chemical fractionation tests on South African coal sources to obtain species-specific information on ash fusion temperatures (AFT)

    Energy Technology Data Exchange (ETDEWEB)

    J.C. van Dyk; L.L. Baxter; J.H.P. van Heerden; R.L.J. Coetzer [Sasol Technology, Sasolburg (South Africa). Syngas and Coal Technologies, R& amp; D Division

    2005-10-01

    Detailed coal and feedstock characteristics are essential to predict gasification performance when a specific coal source is to be gasified. One property that specifically gives detail information on the suitability of a coal source for gasification purposes is the ash fusion temperature (AFT). The AFT of a coal source indicates the extent to which ash agglomeration and ash clinkering are likely to occur within the gasifier. The principal aim of this paper is to obtain mineral species-specific information on ash properties and the specific affect on AFT. Chemical fractionation treatment resulted in coals having different mineral properties that can be used to explain the affect of specific minerals on the AFT of coal. The highest concentration and species of minerals were removed from the coal by acid leaching (HCl and HNO{sub 3}) where Al, Ca, Mg, Na and Fe were removed in high concentrations from the coal. The AFT of coal after leaching increased to {gt}1600{sup o}C. Based on the 95% confidence intervals depicted the following components can be highlighted as having a statistical significant effect on the AFT: Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, CaO, MgO, P{sub 2}O{sub 5} and SiO{sub 2}-Al{sub 2}O{sub 3} combination. When mineral ratio was used, the best correlation coefficient ) with AFT was obtained with the dolomite ratio. This is in agreement with the results obtained from the correlations between the AFT and the ash composition where CaO and MgO resulted in the best correlation with AFT. Results presented in this paper again highlights the fact and confirmed work from other researchers that ash composition (elemental analyses) on its own does not explain AFT behavior or commercial performance of coal accurately. 14 refs., 6 figs., 6 tabs.

  18. Radiobiological waste treatment-ashing treatment and immobilization with cement

    International Nuclear Information System (INIS)

    This report describes the results of the study on the treatment of radioactive biological waste in the China Institute for Radiation Protection (CIRP). The possibility of radiobiological waste treatment was investigated by using a RAF-3 type rapid ashing apparatus together with the immobilization of the resulted ash. This rapid ashing apparatus, developed by CIRP, is usually used for pretreatment of samples prior to chemical analysis and physical measurements. The results show that it can ash 3 kg of animal carcasses a batch, the ashing time is 5-7 h and the ash content is less than 4 wt%. The ashing temperature not exceeding 450 deg. C was used without any risk of high losses of radionuclides. The ash from the rapid ashing apparatus was demonstrated to be immobilized with ordinary silicate cement. The optimum cement/ash/water formulation of the cemented waste form was 35 ± 5 wt% cement, 29 ± 2 wt% water, and 36 ± 6 wt% ash. The performance of the waste form was in compliance with the technical requirements except for impact resistance. Mixing additives in immobilization formulations can improve the performance of the cemented ash waste form. The additives chosen were DH4A flow promoter as a cement additive and vermiculite or zeolite as a supplement. The recommended formulation, i.e. an improved formulation of the cemented ash waste form is that additives DH4A flow promoter and vermiculite (or zeolite) are added on the ground of optimum cement/ash/water formulation of the cemented waste form, the dosage of water, DH4A and vermiculite (or zeolite) is 70 wt%, 0.5 wt% and ≤ 5 wt% of the cement dosage, respectively. The cemented ash waste forms obtained meet all the requirements for disposal. (author). 12 refs, 7 figs, 13 tabs

  19. Leaching behaviour of bottom ash from RDF high-temperature gasification plants

    International Nuclear Information System (INIS)

    This study investigated the physical properties, the chemical composition and the leaching behaviour of two bottom ash (BA) samples from two different refuse derived fuel high-temperature gasification plants, as a function of particle size. The X-ray diffraction patterns showed that the materials contained large amounts of glass. This aspect was also confirmed by the results of availability and ANC leaching tests. Chemical composition indicated that Fe, Mn, Cu and Cr were the most abundant metals, with a slight enrichment in the finest fractions. Suitability of samples for inert waste landfilling and reuse was evaluated through the leaching test EN 12457-2. In one sample the concentration of all metals was below the limit set by law, while limits were exceeded for Cu, Cr and Ni in the other sample, where the finest fraction showed to give the main contribution to leaching of Cu and Ni. Preliminary results of physical and geotechnical characterisation indicated the suitability of vitrified BA for reuse in the field of civil engineering. The possible application of a size separation pre-treatment in order to improve the chemical characteristics of the materials was also discussed.

  20. Experimental study of fly-ash migration under controlled water regime. Temperature and moisture calibration and preliminary results on sand formations

    International Nuclear Information System (INIS)

    Complete text of publication follows. Soil magnetometry can serve as proxy for industrial immisions as well as heavy-metal contamination. An important methodological question related to measurements of top soil magnetic susceptibility is whether migration of deposited anthropgenic ferrimagnetics influences the measured values. In spite o the fact that reliable mapping of magnetic susceptibility requires a high temporal stability of accumulated industrial immisions in topsoils, precise knowledge on the mobility of anthropogenic ferrimagnetics in vertical soil profile (and factors affecting this process) is still lacking. In our model experiments in laboratory we used three technical sands with different particle sizes (0.10 - 1.25 mm). Sands in plastic cylinders were contaminated on the surface by fly-ashes from coal-burning power plant. Soil moisture sensors were used to monitor water regime within the sand columns after controlled rain simulation.Vertical migration of ferrimagnetic particles-tracers presented in the fly-ash was measured by SM400 Kappameter. As a first step, calibration measurements were carried out. in order to define the effect of temperature and different moisture on susceptibility values measured by SM400. We observed systematic increase of susceptibility (∼4 x 10-4SI) for realistic temperature interval in water saturated sand column (from 10 to 26 deg C). On the contrary, diamagnetic effect of water content on magnetic susceptibility is very low (-10-5SI). Preliminary results indicated that after the pulls infiltration of defined water volume, gradual decreases of susceptibility peak values were detected in all studied sand formations. Fly-ash migrated more or less freely in coarse sand material. In medium and fine sand the contaminants moved only to the depths of several cm due to the pore-space blocking and water flow decrease. This research is supported by the Grant Agency ASCR under grant IAA300120701.

  1. Field and seismic evaluation of the block-and-ash flows emplaced from eruption columns of the 2005 Vulcanian explosions at Volcán de Colima, Mexico

    Science.gov (United States)

    Zobin, Vyacheslav M.; Carrasco-Núñez, Gerardo; Vargas-Gutiérrez, Víctor R.

    2016-04-01

    The May-September 2005 Vulcanian explosion sequence was the most intense of all the activity during the recent 1998-2015 unrest at Volcán de Colima, Mexico. This study presents field measurements of volume and runout distances of block-and-ash flows emplaced from eruption columns that punctuated the six largest explosions of this sequence. The energy of these explosions and the emplacement duration of the pyroclastic flows were obtained from broadband seismic signals associated with these events. The field and seismic characteristics of the 2005 explosions at Volcán de Colima and associated block-and-ash flows showed that six explosions with energy ranging between 3.0 × 1011 and 1.5 × 1013 J emplaced the block-and-ash flows with volumes ranging between 1.8 × 105 and 3.1 × 105 m3 DRE (dense rock equivalent). Analysis of durations of seismic signals associated with the movement of the 2005 block-and-ash flows emplaced from the eruption columns allowed us to quantify them as M3-magnitude events using the techniques proposed by Zobin et al. (Bull Volcanol 67: 679-688, 2005) to quantify the block-and-ash flows emplaced from the partial collapse of the lava dome at Volcán de Colima.

  2. A fast Eulerian multiphase flow model for volcanic ash plumes: turbulence, heat transfer and particle non-equilibrium dynamics.

    Science.gov (United States)

    Cerminara, Matteo; Esposti Ongaro, Tomaso; Carlo Berselli, Luigi

    2014-05-01

    We have developed a compressible multiphase flow model to simulate the three-dimensional dynamics of turbulent volcanic ash plumes. The model describes the eruptive mixture as a polydisperse fluid, composed of different types of gases and particles, treated as interpenetrating Eulerian phases. Solid phases represent the discrete ash classes into which the total granulometric spectrum is discretized, and can differ by size and density. The model is designed to quickly and accurately resolve important physical phenomena in the dynamics of volcanic ash plumes. In particular, it can simulate turbulent mixing (driving atmospheric entrainment and controlling the heat transfer), thermal expansion (controlling the plume buoyancy), the interaction between solid particles and volcanic gas (including kinetic non-equilibrium effects) and the effects of compressibility (over-pressured eruptions and infrasonic measurements). The model is based on the turbulent dispersed multiphase flow theory for dilute flows (volume concentration effects only at the first order. We adopt LES formalism (which is preferable in transient regimes) for compressible flows to model the non-linear coupling between turbulent scales and the effect of sub-grid turbulence on the large-scale dynamics. A three-dimensional numerical code has been developed basing on the OpenFOAM computational framework, a CFD open source parallel software package. Numerical benchmarks demonstrate that the model is able to capture important non-equilibrium phenomena in gas-particle mixtures, such as particle clustering and ejection from large-eddy turbulent structures, as well as compressibility and thermal effects. A quantitative assessment of the reliability of Direct Numerical Simulation (DNS) and LES results with respect to modeling approximations and numerical errors has been carried out by comparing numerical results to experimental and computational studies of homogeneous, isotropic turbulence. In such a simplified

  3. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

    Science.gov (United States)

    Saqib, Naeem; Bäckström, Mattias

    2014-12-01

    Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature. PMID:25263218

  4. Fusion characterization of biomass ash

    DEFF Research Database (Denmark)

    Ma, Teng; Fan, Chuigang; Hao, Lifang;

    2016-01-01

    The ash fusion characteristics are important parameters for thermochemical utilization of biomass. In this research, a method for measuring the fusion characteristics of biomass ash by Thermo-mechanical Analyzer, TMA, is described. The typical TMA shrinking ratio curve can be divided into two...... stages, which are closely related to ash melting behaviors. Several characteristics temperatures based on the TMA curves are used to assess the ash fusion characteristics. A new characteristics temperature, Tm, is proposed to represent the severe melting temperature of biomass ash. The fusion...... characteristics of six types of biomass ash have been measured by TMA. Compared with standard ash fusibility temperatures (AFT) test, TMA is more suitable for measuring the fusion characteristics of biomass ash. The glassy molten areas of the ash samples are sticky and mainly consist of K-Ca-silicates....

  5. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    of melt in the investigated ashes has been determined as a function of temperature. Ash fusion results have been correlated to the chemical and mineralogical composition of the ashes, to results from a standard ash fusion test and to results from sintering experiments. Furthermore, the ash fusion results...... straw combustion are characterised by a large fraction of KCl and a smaller fraction of K-, Ca-, Al-silicates and quartz. The salt part of these ashes melt in the temperature range from 600-750°C, whereas the silicate part predominantly melts between 1000 and 1200°C. Increasing salt (KCl) content...... in the ashes lead to increased melt fractions in the temperature range 600-750°C.b) Bottom ashes from straw combustion consist purely of silicates, with varying ratios of the quite refractory Al-silicates and quartz to the less refractory K- and Ca-silicates. Bottom ashes melt in the temperature range 800...

  6. Bulk temperature measurement in thermally striped pipe flows

    International Nuclear Information System (INIS)

    The hot leg flows in some Pressurized Water Reactor (PWR) designs have a temperature distribution across the pipe cross-section. This condition is often referred to as a thermally striped flow. Here, the bulk temperature measurement of pipe flows with thermal striping is explored. An experiment is conducted to examine the feasibility of using temperature measurements on the external surface of the pipe to estimate the bulk temperature of the flow. Simple mixing models are used to characterize the development of the temperature profile in the flow. Simple averaging techniques and Backward Propagating Neural Net are used to predict bulk temperature from the external temperature measurements. Accurate bulk temperatures can be predicted. However, some temperature distributions in the flow effectively mask the bulk temperature from the wall and cause significant error in the bulk temperature predicted using this technique

  7. Correlation and stratigraphic eruption age of the pyroclastic flow deposits and wide spread volcanic ashes intercalated in the Pliocene-Pleistocene strata, central Japan

    International Nuclear Information System (INIS)

    Three pyroclastic flow deposits in the Takayama and Omine area, central Honshu, are correlated to the distal widespread volcanic ashes intercalated in the Plio-Pleistocene boundary strata in central Japan. The correlation is based on these stratigraphic relationships, facies, magnetostratigraphy, petrographic properties such as mineral assemblage, refractive index and chemical composition of the volcanic glasses and orthopyroxene. As the result of these correlation, the eruption age of the proximal pyroclastic flow deposits have become clear. And precise correlation between proximal eruption units and distal depositional units is now possible. Ho-Kd 39 Tephra erupted at about 1.76 Ma, forming a co-ignimbrite ash, which deposited in the Kanto sedimentary basin. Eb-Fukuda Tephra erupted at about 1.75 Ma, and distal volcaniclastic deposit sedimented in the Kinki, Niigata and Kanto sedimentary basins. The eruptional and depositional phase are divided into the stage 1, stage 2 (early), stage 2 (late) and stage 3. Stage 1 is phreato-plinian type eruption phase, forming distal ash fall deposit. Stage 2 (early) is plinian pumice fall, intra-plinian pyroclastic flow and plinian pumice fall eruption phase, forming distal ash fall. Stage 2 (late) is final eruptional phase of the biggest pyroclastic flow of the Eb-Fukuda Tephra, forming a co-ignimbrite ash fall. Stage 3 is resedimented stage after the end of the explosive eruption. It is notable that resedimented volcaniclastic deposit reached Osaka sedimentary basin 300 km away from the eruption center. Om-SK110 Tephra erupted at about 1.65 Ma, divided into the stage 1, stage 2 and stage 3. Stage 1 is eruption phase of the plinian pumice fall and first pyroclastic flow. Stage 2 is pauses in eruption activity. Stage 3 is second pyroclastic flow phase, it is inferred that the pyroclastic flow of the stage 3 directly entered the Niigata sedimentary basin and simultaneously formed a co-ignimbrite ash. (author)

  8. Survey and conceptual flow sheets for coal conversion plant handling-preparation and ash/slag removal operations

    Energy Technology Data Exchange (ETDEWEB)

    Zapp, F.C.; Thomas, O.W.; Silverman, M.D.; Dyslin, D.A.; Holmes, J.M.

    1980-03-01

    This study was undertaken at the request of the Fossil Fuel Processing Division of the Department of Energy. The report includes a compilation of conceptual flow sheets, including major equipment lists, and the results of an availability survey of potential suppliers of equipment associated with the coal and ash/slag operations that will be required by future large coal conversion plant complexes. Conversion plant flow sheet operations and related equipment requirements were based on two representative bituminous coals - Pittsburgh and Kentucky No. 9 - and on nine coal conversion processes. It appears that almost all coal handling and preparation and ash/slag removal equipment covered by this survey, with the exception of some coal comminution equipment, either is on hand or can readily be fabricated to meet coal conversion plant capacity requirements of up to 50,000 short tons per day. Equipment capable of handling even larger capacities can be developed. This approach appears to be unjustified, however, because in many cases a reasonable or optimum number of trains of equipment must be considered when designing a conversion plant complex. The actual number of trains of equipment selected will be influenced by the total requied capacity of the complex, the minimum on-line capacity that can be tolerated in case of equipment failure, reliability of specific equipment types, and the number of reactors and related feed injection stations needed for the specific conversion process.

  9. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt;

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome...... ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of biomass deposits give different characteristics as compared to coal ash deposits, i.e. different physical significance of the deposition mechanisms, lower melting temperatures, etc....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  10. Low temperature setting iron phosphate ceramics as a stabilization and solidification agent for incinerator ash contaminated with transuranic and RCRA metals

    International Nuclear Information System (INIS)

    Incineration of combustible Mixed Transuranic Waste yields an ash residue that contains oxides of Resource Conservation and Recovery Act (RCRA) and transuranic metals. In order to dispose of this ash safely, it has to be solidified and stabilized to satisfy appropriate requirements for repository disposal. This paper describes a new method for solidification of incinerator ash, using room temperature setting iron phosphate ceramics, and includes fabrication procedures for these waste forms as well as results of the MCC-1 static leach test, XRD analysis, scanning electron microscopy studies and density measurements of the solidified waste form produced

  11. Low temperature setting iron phosphate ceramics as a stabilization and solidification agent for incinerator ash contaminated with transuranic and RCRA metals

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, P.G.; Hansen, M.; Wood, E.L.; Frank, S.M.; Sidwell, R.W.; Giglio, J.J.; Johnson, S.G. [Argonne National Lab., Idaho Falls, ID (United States). Engineering Div.; Macheret, J. [Dept. of Energy, Idaho Falls, ID (United States). Idaho Office

    1997-06-01

    Incineration of combustible Mixed Transuranic Waste yields an ash residue that contains oxides of Resource Conservation and Recovery Act (RCRA) and transuranic metals. In order to dispose of this ash safely, it has to be solidified and stabilized to satisfy appropriate requirements for repository disposal. This paper describes a new method for solidification of incinerator ash, using room temperature setting iron phosphate ceramics, and includes fabrication procedures for these waste forms as well as results of the MCC-1 static leach test, XRD analysis, scanning electron microscopy studies and density measurements of the solidified waste form produced.

  12. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature

    International Nuclear Information System (INIS)

    Highlights: • Different solids waste incineration is discussed in grate fired and fluidized bed boilers. • We explained waste composition, temperature and chlorine effects on metal partitioning. • Excessive chlorine content can change oxide to chloride equilibrium partitioning the trace elements in fly ash. • Volatility increases with temperature due to increase in vapor pressure of metals and compounds. • In Fluidized bed boiler, most metals find themselves in fly ash, especially for wood incineration. - Abstract: Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine

  13. Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

    DEFF Research Database (Denmark)

    Wu, Hao; Bashir, Muhammad Shafique; Jensen, Peter Arendt;

    2013-01-01

    Ash transformation and deposition during pulverized wood combustion in a full-scale power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was characterized by using an advanced deposit probe system at two boiler locations...... of the deposits. Overall, the results from this work suggest that coal fly ash can be an effective additive to minimize the possible ash deposition and corrosion problems during suspension-firing of wood. © 2013 Elsevier Ltd. All rights reserved....... constant after a few hours. The formed deposits, especially those at the location with low flue gas temperatures, contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of a large amount (about 4 times of the mass flow of wood ash) of coal fly ash to the boiler, these alkali...

  14. Effects of ambient temperature on egg and larval development of the invasive emerald ash borer (Coleoptera: Buprestidae): implications for laboratory rearing.

    Science.gov (United States)

    Duan, Jian J; Watt, Tim; Taylor, Phil; Larson, Kristi; Lelito, Jonathan P

    2013-10-01

    The emerald ash borer, Agrilus planipennis Fairmaire, an invasive beetle from Asia causing large scale ash (Fraxinus) mortality in North America, has been extremely difficult to rear in the laboratory because of its long life cycle and cryptic nature of immature stages. This lack of effective laboratory-rearing methods has not only hindered research into its biology and ecology, but also mass production of natural enemies for biological control of this invasive pest. Using sticks from the alternate host plant, Fraxinus uhdei (Wenzig) Lingelsh, we characterized the stage-specific development time and growth rate of both emerald ash borer eggs and larvae at different constant temperatures (12-35 degrees C) for the purpose of developing effective laboratory-rearing methods. Results from our study showed that the median time for egg hatching decreased from 20 d at 20 degrees C to 7 d at 35 degrees C, while no emerald ash borer eggs hatched at 12 degrees C. The developmental time for 50% of emerald ash borer larvae advancing to third, fourth, and J-larval stages at 20 degrees C were 8.3, 9.1, and 12.3 wk, respectively, approximately two times longer than at 30 degrees C for the corresponding instars or stages. In contrast to 30 degrees C, however, the development times of emerald ash borer larvae advancing to later instars (from oviposition) were significantly increased at 35 degrees C, indicating adverse effects of this high temperature. The optimal range of ambient temperature to rear emerald ash borer larvae should be between 25-30 degrees C; however, faster rate of egg and larval development should be expected as temperature increases within this range. PMID:24224252

  15. 14C ages of the Ata pyroclastic flow and the Kaimon volcanic ash bed in the Kagoshima Prefecture

    International Nuclear Information System (INIS)

    In southern Kyushu, volcanic ejecta of different ages and sources are widely distributed. Their age determination is important in connection with the history of recent volcanic activities. Of the volcanic ejecta, for the Irito-Tsumaya pyroclastic flow and Osumi fallout pumice layer originating from Aira Caldera and distributing most widely, the age of about 22,000 y.B.P. has been established. For the underlying Ata pyroclastic flow, however, the measured age is yet few, therefore it is not established. In the Nansatsu area (southern Kyushu), where volcanic ejecta originating from Kaimon-take are distributed in uppermost layer, the determined age in the lowermost layer indicating the initiation of Kaimon-take activity is few. From the Ata pyroclastic flow, two samples of carbonized wood were taken, and from the Kaimon volcanic ash bed of initial eruption, one sample of carbonized wood was taken. The 14C ages determined are 32,900 +- 3,900 y.B.P. and 28,600 y.B.P. for the former two and 4,040 +- 120 y.B.P. for the latter one. (J.P.N.)

  16. Integrated flow and temperature modeling at the catchment scale

    DEFF Research Database (Denmark)

    Loinaz, Maria Christina; Davidsen, Hasse Kampp; Butts, Michael;

    2013-01-01

    including temperature data in an integrated flow model calibration because temperature data provide additional constraints on the flow sources and volumes. Simulations show that a reduction of 10% in the groundwater flow to the Silver Creek Basin can cause average and maximum temperature increases in Silver......Changes in natural stream temperature levels can be detrimental to the health of aquatic ecosystems. Water use and land management directly affect the distribution of diffuse heat sources and thermal loads to streams, while riparian vegetation and geomorphology play a critical role in how thermal...... loads are buffered. In many areas, groundwater flow is a significant contribution to river flow, particularly during low flows and therefore has a strong influence on stream temperature levels and dynamics. However, previous stream temperature models do not properly simulate how surface water...

  17. Ash reduction system using electrically heated particulate matter filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI; Paratore, Jr., Michael J; He, Yongsheng [Sterling Heights, MI

    2011-08-16

    A control system for reducing ash comprises a temperature estimator module that estimates a temperature of an electrically heated particulate matter (PM) filter. A temperature and position estimator module estimates a position and temperature of an oxidation wave within the electrically heated PM filter. An ash reduction control module adjusts at least one of exhaust flow, fuel and oxygen levels in the electrically heated PM filter to adjust a position of the oxidation wave within the electrically heated PM filter based on the oxidation wave temperature and position.

  18. High temperature capture of CO{sub 2} on lithium-based sorbents from rice husk ash

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Guo, Xin, E-mail: guoxin@mail.hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhao, Pengfei; Wang, Fanzi; Zheng, Chuguang [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-05-15

    Highly efficient Li{sub 4}SiO{sub 4} (lithium orthosilicate)-based sorbents for CO{sub 2} capture at high temperature, was developed using waste materials (rice husk ash). Two treated rice husk ash (RHA) samples (RHA1 and RHA2) were prepared and calcined at 800 {sup o}C in the presence of Li{sub 2}CO{sub 3}. Pure Li{sub 4}SiO{sub 4} and RHA-based sorbents were characterized by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetry. CO{sub 2} sorption was tested through 15 carbonation/calcination cycles in a fixed bed reactor. The metals of RHA were doped with Li{sub 4}SiO{sub 4} resulting to inhibited growth of the particles and increased pore volume and surface area. Thermal analyses indicated a much better CO{sub 2} absorption in Li{sub 4}SiO{sub 4}-based sorbent prepared from RHA1 (higher metal content sample) because the activation energies for the chemisorption process and diffusion process were smaller than that of pure Li{sub 4}SiO{sub 4}. RHA1-based sorbent also maintained higher capacities during the multiple cycles.

  19. Simultaneous Temperature and Velocity Diagnostic for Reacting Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A diagnostic technique is proposed for measuring temperature and velocity simultaneously in a high temperature reacting flow for aiding research in propulsion. The...

  20. Removal of fly-ash and dust particulate matters from syngas produced by gasification of coal by using a multi-stage dual-flow sieve plate wet scrubber.

    Science.gov (United States)

    Kurella, Swamy; Meikap, Bhim Charan

    2016-08-23

    In this work, fly-ash water scrubbing experiments were conducted in a three-stage lab-scale dual-flow sieve plate scrubber to observe the performance of scrubber in fly-ash removal at different operating conditions by varying the liquid rate, gas rate and inlet fly-ash loading. The percentage of fly-ash removal efficiency increases with increase in inlet fly-ash loading, gas flow rate and liquid flow rate, and height of the scrubber; 98.55% maximum percentage of fly-ash removal efficiency (ηFA) is achieved at 19.36 × 10(-4) Nm(3)/s gas flow rate (QG) and 48.183 × 10(-6) m(3)/s liquid flow rate (QL) at 25 × 10(-3) kg/Nm(3) inlet fly-ash loading (CFA,i). A model has also been developed for the prediction of fly-ash removal efficiency of the column using the experimental results. The predicted values calculated using the correlation matched well with the experimental results. Deviations observed between the experimental and the predicted values were less than 20%. PMID:27230635

  1. Analysis of the 2006 block-and-ash flow deposits of Merapi Volcano, Java, Indonesia, using high-spatial resolution IKONOS images and complementary ground based observations

    Science.gov (United States)

    Thouret, Jean-Claude; Gupta, Avijit; Liew, Soo Chin; Lube, Gert; Cronin, Shane J.; Surono, Dr

    2010-05-01

    On 16 June 2006 an overpass of IKONOS coincided with the emplacement of an active block-and-ash flow fed by a lava dome collapse event at Merapi Volcano (Java, Indonesia). This was the first satellite image recorded for a moving pyroclastic flow. The very high-spatial resolution data displayed the extent and impact of the pyroclastic deposits emplaced during and prior to, the day of image acquisition. This allowed a number of features associated with high-hazard block-and-ash flows emplaced in narrow, deep gorges to be mapped, interpreted and understood. The block-and-ash flow and surge deposits recognized in the Ikonos images include: (1) several channel-confined flow lobes and tongues in the box-shaped valley; (2) thin ash-cloud surge deposit and knocked-down trees in constricted areas on both slopes of the gorge; (3) fan-like over bank deposits on the Gendol-Tlogo interfluves from which flows were re-routed in the Tlogo secondary valley; (4) massive over bank lobes on the right bank from which flows devastated the village of Kaliadem 0.5 km from the main channel, a small part of this flow being re-channeled in the Opak secondary valley. The high-resolution IKONOS images also helped us to identify geomorphic obstacles that enabled flows to ramp and spill out from the sinuous channel, a process called flow avulsion. Importantly, the avulsion redirected flows to unexpected areas away from the main channel. In the case of Merapi we see that the presence of valley fill by previous deposits, bends and man-made dams influence the otherwise valley-guided course of the flows. Sadly, Sabo dams (built to ameliorate the effect of high sediment load streams) can actually cause block-and-ash flows to jump out of their containing channel and advance into sensitive areas. Very-high-spatial resolution satellite images are very useful for mapping and interpreting the distribution of freshly erupted volcanic deposits. IKONOS-type images with 1-m resolution provide opportunities to

  2. Measuring Temperature in Pipe Flow with Non-Homogeneous Temperature Distribution

    Science.gov (United States)

    Klason, P.; Kok, G. J.; Pelevic, N.; Holmsten, M.; Ljungblad, S.; Lau, P.

    2014-04-01

    Accurate temperature measurements in flow lines are critical for many industrial processes. It is normally more a rule than an exception in such applications to obtain water flows with inhomogeneous temperature distributions. In this paper, a number of comparisons were performed between different 100 ohm platinum resistance thermometer (Pt-100) configurations and a new speed-of-sound-based temperature sensor used to measure the average temperature of water flows with inhomogeneous temperature distributions. The aim was to achieve measurement deviations lower than 1 K for the temperature measurement of water flows with inhomogeneous temperature distributions. By using a custom-built flow injector, a water flow with a hot-water layer on top of a cold-water layer was created. The temperature difference between the two layers was up to 32 K. This study shows that the deviations to the temperature reference for the average temperature of four Pt-100s, the multisensor consisting of nine Pt-100s, and the new speed-of-sound sensors are remarkably lower than the deviation for a single Pt-100 under the same conditions. The aim of reaching a deviation lower than 1 K was achieved with the speed-of-sound sensors, the configuration with four Pt-100s, and the multisensor. The promising results from the speed-of sound temperature sensors open the possibility for an integrated flow and temperature sensor. In addition, the immersion depth of a single Pt-100 was also investigated at three different water temperatures.

  3. Temperature and flow distribution in planar SOFC stacks

    Directory of Open Access Journals (Sweden)

    Monica Østenstad

    1995-07-01

    Full Text Available Simulation of a planar Solid Oxide Fuel Cell stack requires the solution of the mass balances of the chemical species, the energy balances, the charge balance and the channel flow equations in order to compute the species concentrations, the temperature distributions, the current density and the channel flows. The unit cell geometry can be taken into account by combining detailed modeling of a unit cell with a homogenized model of a whole stack. In this study the effect of the asymmetric temperature distribution on the channel flows in a conventional cross-flow design has been investigated. The bidirectional cross-flow design is introduced, for which we can show more directional temperature and flow distributions.

  4. Experimental investigation of R-245fa flow boiling in minichannels at high saturation temperatures: Flow patterns and flow pattern maps

    International Nuclear Information System (INIS)

    Highlights: • Image processing method and analysis of the heat transfer coefficient for two-phase flow pattern characterization. • Four flow patterns (intermittent flow, annular flow, dryout flow and mist flow) and their transitions were recognized. • The influence of the high saturation temperature (up to 120 °C) on flow pattern with R-245fa was investigated. • Comparisons with available transition lines in the literature were made. - Abstract: In this work, flow visualizations and measurements are carried out to identify flow regime transitions during the flow boiling of R-245fa in a 3.00 mm inner diameter minichannel at high saturation temperatures, i.e. saturation temperature ranging from 60 °C to 120 °C. Flow boiling experiments at such high temperatures have so to say almost not been reported in the open literature so far. The mass velocity is ranging from 100 to 1500 kg/m2 s, the heat flux is varying from 10 to 50 kW/m2 and the inlet vapor quality from 0 to 1. Based on an image processing method and with the help of an adequate analysis of the heat transfer coefficient, four main flow regimes can be identified: intermittent flow, annular flow, dryout and mist flow. Their transitions were detected and plotted on flow pattern maps. The influence of the heat flux and the saturation temperature are highlighted and discussed. Comparisons with available transition lines in the literature have been made. Whereas the flow regime would suggest a macroscale type of flow, the flow patterns transitions are closer to those observed in microscale

  5. Spreading dynamic of viscous volcanic ash in stimulated jet engine conditions

    Science.gov (United States)

    song, wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado

    2016-04-01

    The ingestion of volcanic ash is widely recognised as a potentially fatal hazard for aircraft operation. The volcanic ash deposition process in a jet turbine is potentially complex. Volcanic ash in the air stream enters the inner liners of the combustors and partially or completely melts under the flames up to 2000 °C, at which point part of the ash deposits in the combustor fuel nozzle. Molten volcanic particles within high energy airflow escape the combustor to enter the turbine and impact the stationary (e.g., inlet nozzle guide vanes) and rotating airfoils (e.g., first stage high-pressure turbine blades) at high speed (up to Mach 1.25) in different directions, with the result that ash may stick, flow and remain liquid or solidify. Thus, the wetting behaviour of molten volcanic ash particle is fundamental to investigate impingement phenomena of ash droplet on the surface of real jet engine operation. The topic of wetting has received tremendous interest from both fundamental and applied points of view. However, due to the interdisciplinary gap between jet engine engineering and geology science, explicit investigation of wetting behaviour of volcanic ash at high temperature is in its infancy. We have taken a big step towards meeting this challenge. Here, we experimentally and theoretically investigate the wetting behaviour of viscous volcanic ash over a wide temperature range from 1100 to 1550 °C using an improved sessile-drop method. The results of our experiment demonstrate that temperature and viscosity play a critical role in determining the wetting possibility and governing the spreading kinetics of volcanic ash at high temperatures. Our systemic analysis of spreading of molten volcanic ash systems allows us to report on the fundamental differences between the mechanisms controlling spreading of organic liquids at room temperature and molten volcanic ash droplets.

  6. Soil application of ash produced by low-temperature fluidized bed gasification: effects on soil nutrient dynamics and crop response

    DEFF Research Database (Denmark)

    Müller-Stöver, Dorette Sophie; Ahrenfeldt, Jesper; Holm, Jens Kai;

    2012-01-01

    investigate the effects of the ashes on soil microbiological and chemical properties and on the response of the three crops. The ash treatments were compared with a control treatment that received only nitrogen, magnesium, and sulphur (CO) and a fully fertilized control (COPK). Soil microbial parameters were...... not significantly altered after ash application. SA was generally able to increase the levels of Olsen-P and of the ammonium acetate/acetic acid-extractable K in soil as well as to improve the yield of barley and maize, whereas faba bean did not react positively to ash amendment. CP did not show...... beneficial effects on soil nutrient levels or on crop biomass. We conclude from the results of this study, that—depending on the feedstock used—ashes from LT-CFB gasification of plant biomass can be used to replace mineral fertilizers if they are applied according to their nutrient content, the crop demand...

  7. Skin temperature and subcutaneous adipose blood flow in man

    DEFF Research Database (Denmark)

    Astrup, A; Bülow, J; Madsen, J

    1980-01-01

    correlation between skin temperature and ATBF. In the range from 25 to 37 degrees CATBF increased 9% of the control flow on average per centigrade increase in skin temperature. ATBF at the control side was uninfluenced by the contralateral variations in skin temperature. Although no better correlation could......The abdominal subcutaneous adipose tissue blood flow (ATBF) was measured bilaterally by the 133Xe washout method. At one side of the skin (epicutaneous) temperature was varied with a temperature blanket, the other side served as control. There was a significant (P less than 0.001) positive...... be demonstrated between ATBF and subcutaneous temperature than between ATBF and skin temperature, arguments are presented in favour of the hypothesis that ATBF is influenced by the subcutaneous temperature rather than via reflexes from the skin. Infiltration of the 133Xe depots with 20 microgram...

  8. Ash Properties of Alternative Biomass

    DEFF Research Database (Denmark)

    Capablo, Joaquin; Jensen, Peter Arendt; Pedersen, Kim Hougaard;

    2009-01-01

    The ash behavior during suspension firing of 12 alternative solid biofuels, such as pectin waste, mash from a beer brewery, or waste from cigarette production have been studied and compared to wood and straw ash behavior. Laboratory suspension firing tests were performed on an entrained flow...... reactor and a swirl burner test rig, with special emphasis on the formation of fly ash and ash deposit. Thermodynamic equilibrium calculations were performed to support the interpretation of the experiments. To generalize the results of the combustion tests, the fuels are classified according to fuel ash...... analysis into three main groups depending upon their ash content of silica, alkali metal, and calcium and magnesium. To further detail the biomass classification, the relative molar ratio of Cl, S, and P to alkali were included. The study has led to knowledge on biomass fuel ash composition influence on...

  9. Measuring Water Vapor and Ash in Volcanic Eruptions with a Millimeter-Wave Radar/Imager

    CERN Document Server

    Bryan, Sean; Vanderkluysen, Loÿc; Groppi, Christopher; Paine, Scott; Bliss, Daniel W; Aberle, James; Mauskopf, Philip

    2016-01-01

    Millimeter-wave remote sensing technology can significantly improve measurements of volcanic eruptions, yielding new insights into eruption processes and improving forecasts of drifting volcanic ash for aviation safety. Radiometers can measure water vapor density and temperature inside eruption clouds, improving on existing measurements with infrared cameras that are limited to measuring the outer cloud surface. Millimeter-wave radar can measure the 3D mass flow of volcanic ash inside eruption plumes and drifting fine ash clouds, offering better sensitivity than existing weather radar measurements and the unique ability to measure ash particle size in-situ. Here we present sensitivity calculations in the context of developing the WAMS (Water and Ash Millimeter-wave Spectrometer) instrument. WAMS, a radar/radiometer system constructed with off-the-shelf components, would be able to measure water vapor and ash throughout an entire eruption cloud, a unique capability.

  10. Volcanic ash melting under conditions relevant to ash turbine interactions.

    Science.gov (United States)

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B

    2016-01-01

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines. PMID:26931824

  11. Volcanic ash melting under conditions relevant to ash turbine interactions

    Science.gov (United States)

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B.

    2016-03-01

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines.

  12. Acoustic tomographic imaging of temperature and flow fields in air

    International Nuclear Information System (INIS)

    Acoustic travel-time tomography is a remote sensing technique that uses the dependence of sound speed in air on temperature and wind speed along the sound propagation path. Travel-time measurements of acoustic signals between several sound sources and receivers travelling along different paths through a measuring area give information on the spatial distribution of temperature and flow fields within the area. After a separation of the two influences, distributions of temperature and flow can be reconstructed using inverse algorithms. As a remote sensing method, one advantage of acoustic travel-time tomography is its ability to measure temperature and flow field quantities without disturbing the area under investigation due to insertion of sensors. Furthermore, the two quantities—temperature and flow velocity—can be recorded simultaneously with this measurement method. In this paper, an acoustic tomographic measurement system is introduced which is capable of resolving three-dimensional distributions of temperature and flow fields in air within a certain volume (1.3 m × 1.0 m × 1.2 m) using 16 acoustic transmitter–receiver pairs. First, algorithms for the 3D reconstruction of distributions from line-integrated measurements are presented. Moreover, a measuring apparatus is introduced which is suited for educational purposes, for demonstration of the method as well as for indoor investigations. Example measurements within a low-speed wind tunnel with different incident flow situations (e.g. behind bluff bodies) using this system are shown. Visualizations of the flow illustrate the plausibility of the tomographically reconstructed flow structures. Furthermore, alternative individual measurement methods for temperature and flow speed provide comparable results

  13. On the Viability of Two-temperature Accretion Flows

    OpenAIRE

    Quataert, Eliot

    2003-01-01

    Binney (2003) has argued that two-temperature radiatively inefficient accretion flow models are unphysical because the electron-ion equipartition time is much shorter than the accretion time. I show that this conclusion is incorrect because it relies on a misidentification of the electron-ion equipartition time. I also clarify what requirements must, in fact, be satisfied to maintain a two-temperature accretion flow.

  14. Pipeline flow of heavy oil with temperature-dependent viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Maza Quinones, Danmer; Carvalho, Marcio da Silveira [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Mechanical Engineering], E-mail: msc@puc-rio.br

    2010-07-01

    The heavy oil produced offshore needs to be transported through pipelines between different facilities. The pipelines are usually laid down on the seabed and are submitted to low temperatures. Although heavy oils usually present Newtonian behavior, its viscosity is a strong function of temperature. Therefore, the prediction of pressure drops along the pipelines should include the solution of the energy equation and the dependence of viscosity to temperature. In this work, an asymptotic model is developed to study this problem. The flow is considered laminar and the viscosity varies exponentially with temperature. The model includes one-dimensional equations for the temperature and pressure distribution along the pipeline at a prescribed flow rate. The solution of the coupled differential equation is obtained by second-order finite difference. Results show a nonlinear behavior as a result of coupled interaction between the velocity, temperature, and temperature dependent material properties. (author)

  15. Modelling the evolution of temperature in avalanche flow

    Science.gov (United States)

    Vera, Cesar; Christen, Marc; Funk, Martin; Bartelt, Perry

    2013-04-01

    Because the mechanical properties of snow are temperature dependent, snow temperature has a strong influence on avalanche flow behaviour. In fact, snow avalanche classification schemes implicitly account for the below-zero temperature regime, i.e. wet snow avalanches contain warm moist snow, whereas dry flowing or powder avalanches consist of colder snow. Although thermal effects are an important feature of avalanche flow behaviour, the temperature field is usually not considered in avalanche dynamics calculations. In this presentation we explicitly model the temperature evolution of avalanches by extending the basic set of depth-averaged differential equations of mass, momentum and fluctuation energy to include a depth-averaged internal energy equation. Two dissipative processes contribute to the irreversible rise in internal energy: the shear work and the dissipation of fluctuation energy due to random granular interactions. Snow entrainment is also an important source of thermal energy. As the temperature of the snow can vary between the release area and runout zone, we model the effect of snowcover temperature elevation gradients. Additionally we introduce a physical constraint on the temperature field to account for phase changes: when the temperature of the avalanche flow surpasses the melting point of ice, the surplus rise in internal energy is used to produce meltwater. We do not consider heat losses due to sensible heat exchanges between the atmosphere and the avalanche. Using numerical simulations we demonstrate how the temperature of the snow in the release area in relation to the temperature of the snowcover encountered by the avalanche at lower elevations can modify avalanche velocity and runout behaviour. We show how the production of turbulent fluctuation energy, which separates dense and dilute, fluidized flow regimes, can be controlled by temperature, creating a wide-range of avalanche deposition patterns. Finally, we investigate under what thermal

  16. Electrodialytic extraction of phosphorus from ash of low-temperature gasification of sewage sludge

    DEFF Research Database (Denmark)

    Viader, Raimon Parés; Jensen, Pernille Erland; Ottosen, Lisbeth M.; Hauggaard-Nielsen, Henrik; Ahrenfeldt, Jesper

    2015-01-01

    100-400 years [1]. In 2012 EU imported 88% of the phosphate rock consumed. Since only about one fourth of the P applied to agricultural fields is actually recycled today [2], innovative recycling and re-use concepts need to be developed and adopted. Low-temperature gasification allows an energy...... process. However, major concerns are its heavy metal content and the low plant availability of P; hence, a separation of phosphorus from the bulk bioashes and heavy metals would be beneficial....

  17. Measured gas and particle temperatures in VTT's entrained flow reactor

    DEFF Research Database (Denmark)

    Clausen, Sønnik; Sørensen, L.H.

    2006-01-01

    Particle and gas temperature measurements were carried out in experiments on VTTs entrained flow reactor with 5% and 10% oxygen using Fourier transform infrared emission spectroscopy (FTIR). Particle temperature measurements were performed on polish coal,bark, wood, straw particles, and bark and...

  18. Operating experience using venturi flow meters at liquid helium temperature

    International Nuclear Information System (INIS)

    Experiences using commercial venturi to measure single phase helium flow near 4 K (degree Kelvin) for cooling superconducting magnets have been presented. The mass flow rate was calculated from the differential pressure and the helium density evaluated from measured pressure and temperature. The venturi flow meter, with a full range of 290 g/s (0.29 Kg/s) at design conditions, has been found to be reliable and accurate. The flow measurements have been used, with great success, for evaluating the performance of a cold centrifugal compressor, the thermal acoustic heat load of a cryogenic system and the cooling of a superconducting magnet after quench

  19. The Measurement and Calculation of Temperature of the Furnace Tube with Ash Deposition%积灰炉管管壁温度的检测与计算

    Institute of Scientific and Technical Information of China (English)

    孙全胜

    2012-01-01

    通过对积灰炉管的传热过程分析建立传热模型,并确定炉管表面温度计算公式.对比计算结果与刮去灰垢后管壁温度,发现二者基本吻合,证明此计算方法可得到比较准确的管壁温度,以保证生产的安全运行.%Base on analysing the heat transfer process of furnace tube with ash deposition, established the heat transfer model and the computational formula for the temperature of tube surface. Comparing the computing resultes with the temperater of the tube surface without ash deposition, we can find that they are consistent with each other. Accurate furnace tuber temperature would be got using the computationeli for mula, in order to ensure the safe operation.

  20. Dielectric properties of fly ash

    Indian Academy of Sciences (India)

    S C Raghavendra; R L Raibagkar; A B Kulkarni

    2002-02-01

    This paper reports the dielectric properties of fly ash. The dielectric measurements were performed as a function of frequency and temperature. The sample of fly ash shows almost similar behaviour in the frequency and temperature range studied. The large value of dielectric constant in the typical frequency range is because of orientation polarization and tight binding force between the ions or atoms in the fly ash. The sample of fly ash is of great scientific and technological interest because of its high value of dielectric constant (104).

  1. Investigation of flow behaviour of coat/ash particles in an advanced pressurised fluidized bed gasifier (APFBG) using radiotracer technique

    International Nuclear Information System (INIS)

    Knowledge of Residence Time Distribution (RTD), Mean Residence Time (MRT) and degree of backmixing of solid phase is important for efficient operation of the coal gasifier. Radiotracer technique was used for measure RTD of coal/ash particles in a pilot-scale gasifier and obtain the values of MRT and backmixing. Lanthanum 140 labeled coal (100 g) was used as a tracer. The tracer was instantaneously injected into the coal feed line and monitored at ash and gas outlets of the gasifier using collimated scintillation detectors. The measured RTD data were treated and MRTs of coal/ash particles were determined. The treated data were simulated using tank-in-series model. The simulation RTD data indicated good degree of mixing with minor bypassing/short-circulating of coal particles. The results of the investigation were found useful for scale-up of the gasification process. (author)

  2. Experimental study on low temperature thermal treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) in fly ash

    Institute of Scientific and Technical Information of China (English)

    YAN Jianhua; CHEN Tong; LU Shengyong; LI Xiaodong; GU Yueling; CEN Kefa

    2007-01-01

    The effects of temperature and time on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)distribution in fly ash of a municipal solid waste incinerator(MSWI) were studied in a tubular oven under nitrogen atmosphere.The PCDD/Fs in the gas phase and solid phase were detected by high-resolution gas chromatography coupled with low resolution mass spectrometry (HRGC/LRMS)separately.The experimental results showed that the major congener was octa-chlorinated dibenzo-p-dioxin (OCDD) in the gas phase and the low chlorinated congeners were the major products in the solid phase.There were high levels of OCDD in the gas phase in several experimental conditions althoughthe PCDD/Fs in the solid phase could be decomposed.The optimum condition for PCDD/Fs decomposition in fly ash was a heating time of 60 min at 400 ℃ under nitrogen atmosphere.

  3. Effects of air flow directions on composting process temperature profile

    International Nuclear Information System (INIS)

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO2 and O2 ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2

  4. Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

    Directory of Open Access Journals (Sweden)

    Bernal, S. A.

    2015-06-01

    Full Text Available This study assessed the mechanical properties, and structural changes induced by high temperature exposure, of alkali-silicate activated slag cements produced with sodium silicates derived from silica fume (SF and rice husk ash (RHA. Similar reaction products were identified, independent of the type of silicate used, but with subtle differences in the composition of the C-S-H gels, leading to different strength losses after elevated temperature exposure. Cements produced with the alternative activators developed higher compressive strengths than those produced with commercial silicate. All samples retained strengths of more than 50 MPa after exposure to 600 °C, however, after exposure to 800 °C only the specimens produced with the RHA-based activator retained measurable strength. This study elucidated that silicate-activated slag binders, either activated with commercial silicate solutions or with sodium silicates based on SF or RHA, are stable up to 600 °C.Este estudio evaluó las propiedades mecánicas, y cambios estructurales inducidos por exposición a temperaturas elevadas, de cementos de escoria activada alcalinamente producidos con silicatos sódicos derivados de humo de sílice (SF y ceniza de cascarilla de arroz (RHA. Se identificaron productos de reacción similares, independiente del tipo de silicato utilizado, pero con diferencias menores en la composición de las geles C-S-H, lo cual indujo diferentes pérdidas de resistencia posterior a exposición a temperaturas elevadas. Los cementantes producidos con los activadores alternativos desarrollaron resistencias a la compresión más altas que aquellos producidos con silicato comercial. Todas las muestras retuvieron resistencias de más de 50 MPa posterior a la exposición a 600 °C, sin embargo, posterior a la exposición a 800 °C únicamente muestras producidas con activadores de RHA retuvieron resistencias medibles. Este estudio elucidó que cementantes de escoria activada con

  5. Sintesis ZSM-5 dari Fly Ash Sawit Sebagai Sumber Silika dengan Variasi Nisbah Molar Si/Al dan Temperatur Sintesis

    OpenAIRE

    Ida Zahrina; Yelmida Yelmida; Fajril Akbar

    2012-01-01

    Palm fly ash is biomass/waste in the  palm oil industry. Palm fly ash has high content of amorphous silica. ZSM-5 is one of synthetic zeolite which is widely used as catalyst in industries. ZSM-5 has high activity and selectivity to several hydrocarbon conversion reaction. Hence, ZSM-5 is being investigated for the conversion of vegetable oil to hydrocarbon.  It can be synthesized from silica and alumina. Sources of silica that can be added to the ZSM-5 synthesis,  are sodium silicate, hydrat...

  6. Multicomponent, multiphase flow in porous media with temperature variation

    Energy Technology Data Exchange (ETDEWEB)

    Wingard, J.S.; Orr, F.M. Jr.

    1990-10-01

    Recovery of hydrocarbons from porous media is an ongoing concern. Advanced techniques augment conventional recovery methods by injecting fluids that favorably interact with the oil. These fluids interact with the oil by energy transfer, in the case of steam injection, or by mass transfer, as in a miscible gas flood. Often both thermal and compositional considerations are important. An understanding of these injection methods requires knowledge of how temperature variations, phase equilibrium and multiphase flow in porous media interact. The material balance for each component and energy balance are cast as a system of non-strictly hyperbolic partial differential equations. This system of equations is solved using the method of characteristics. The model takes into account the phase behavior by using the Peng-Robinson equation of state to partition the individual components into different phases. Temperature effects are accounted for by the energy balance. Flow effects are modelled by using fractional flow curves and a Stone's three phase relative permeability model. Three problems are discussed. The first problem eliminates the phase behavior aspect of the problem by studying the flow of a single component as it undergoes an isothermal phase change. The second couples the effects of temperature and flow behavior by including a second component that is immiscible with the original component. Phase behavior is added by using a set of three partially miscible components that partition into two or three separate phases. 66 refs., 54 figs., 14 tabs.

  7. Ash formation, deposition, corrosion, and erosion in conventional boilers

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.A.; Jones, M.L. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-12-01

    The inorganic components (ash-forming species) associated with coals significantly affect boiler design, efficiency of operation, and lifetimes of boiler parts. During combustion in conventional pulverized fuel boilers, the inorganic components are transformed into inorganic gases, liquids, and solids. This partitioning depends upon the association of the inorganic components in the coal and combustion conditions. The inorganic components are associated as mineral grains and as organically associated elements, and these associations of inorganic components in the fuel directly influence their fate upon combustion. Combustion conditions, such as temperature and atmosphere, influence the volatility and the interaction of inorganic components during combustion and gas cooling, which influences the state and size composition distribution of the particulate and condensed ash species. The intermediate species are transported with the bulk gas flow through the combustion systems, during which time the gases and entrained ash are cooled. Deposition, corrosion, and erosion occur when the ash intermediate species are transported to the heat-transfer surface, react with the surface, accumulate, sinter, and develop strength. Research over the past decade has significantly advanced understanding of ash formation, deposition, corrosion, and erosion mechanisms. Many of the advances in understanding and predicting ash-related issues can be attributed to advanced analytical methods to determine the inorganic composition of fuels and the resulting ash materials. These new analytical techniques have been the key to elucidation of the mechanisms of ash formation and deposition. This information has been used to develop algorithms and computer models to predict the effects of ash on combustion system performance.

  8. High-temperature entrained flow gasification of biomass

    DEFF Research Database (Denmark)

    Qin, Ke; Lin, Weigang; Jensen, Peter Arendt;

    2012-01-01

    Biomass (wood and straw) gasification has been studied in a laboratory scale atmospheric pressure entrained flow reactor. Effects of reaction temperature, steam/carbon molar ratio, excess air ratio, and biomass type on the solid, liquid and gas products were investigated. The biomass was completely...

  9. Wildland fire ash: future research directions

    Science.gov (United States)

    Bodí, Merche B.; Martins, Deborah A.; Cerdà, Artemi; Balfour, Victoria N.; Santin, Cristina; Doerr, Stefan H.; Pereira, Paulo; Mataix-Solera, Jorge

    2014-05-01

    Ash is a key component of the forest fires affected land (Cerdà, 1998; Bodí et al., 2011; Pereira et al., 2013a). Ash controls the hydrological processes and determines the water repellency (Dlapa et al., 2012) and the infiltration rates (Cerdà and Doerr, 2008;). Moreover, ash is the key factor on runoff initiation and then on the soil erosion. Little is known about the impact of ash in different ecosystems, but during the last decade a substantial increase in the papers that show the role of ash in the Earth and Soil System were published (Bodí et al., 2012; Pereira et al., 2013b).. Ash is being found as the key component of the post-fire pedological, geomorphological and hydrological response after forest fires (Fernández et al., 2012; Martín et al., 2012; Bodí et al., 2013; Guénon et al., 2013; Pereira et al., 2013c). A recent State-of-the-Art review about wildland fire ash (Bodí et al., 2014) compiles the knowledge regarding the production, composition and eco-hydro-geomorphic effects of wildland fire ash. In the present paper we indicate the knowledge gaps detected and suggest topics that need more research effort concerning: i) data collection and analysis techniques: a) To develop standardized sampling techniques that allow cross comparison among sites and avoid inclusion of the underlying soil unless the burned surface soil forms part of the ash layer, b) To develop standardized methods to define and characterize ash, including its color, physical properties such as particle size distribution or density, proportion of pyrogenic C, chemical and biological reactivity and persistence in the environment, c) To validate, calibrate and test measurements collected through remote sensing with on-the-ground measurements. ii) ash production, deposition redistribution and fate: d) To untangle the significance of the effects of maximum temperature reached during combustion versus the duration of heating, e) To understand the production of ash by measuring its

  10. Global Stream Temperatures and Flows under Climate Change

    Science.gov (United States)

    van Vliet, M. T.; Yearsley, J. R.; Franssen, W. H.; Ludwig, F.; Haddeland, I.; Lettenmaier, D. P.; Kabat, P.

    2012-12-01

    Climate change will affect thermal and hydrologic regimes of rivers, having a direct impact on human water use and freshwater ecosystems. Here we assess the impact of climate change on stream temperature and streamflow globally. We used a physically-based stream temperature river basin model (RBM) linked to the Variable Infiltration Capacity (VIC) model. The modelling framework was adapted for global application including impacts of reservoirs and thermal heat discharges, and was validated using observed water temperature and river discharge records in large river basins globally. VIC-RBM was forced with an ensemble of bias-corrected Global Climate Model (GCM) output resulting in global projections of daily streamflow and water temperature for the 21st century. Global mean and high (95th percentile) stream temperatures are projected to increase on average by 0.8-1.6 (1.0-2.2)°C for the SRES B1-A2 scenario for 2071-2100 relative to 1971-2000. The largest water temperature increases are projected for Europe, North America, Southeast Asia, South Africa and parts of Australia. In these regions, the sensitivities for warming are exacerbated by projected decreases in summer low flows. Large increases in water temperature combined with decreases in low flows are found for the southeastern U.S., Europe and eastern China. These regions could potentially be affected by increased deterioration of water quality and freshwater habitats, and reduced water available for beneficial uses such as thermoelectric power production.

  11. Use of ashes and ash-and-slad wastes in construction

    Directory of Open Access Journals (Sweden)

    P. Lahtinen

    2011-06-01

    Full Text Available The use of ash waste saves expenses on main materials without compromising the quality of the product, while solving the problem of disposal of ash materials. The aim of this work is classification of ashes and evaluation its use in construction.Classification of ash-and-slad wastes based on type of burned coal, way of incineration, flame temperature, way of ash disposal is made. The chemical composition and behavior of shale ash, its main deposits, its advantages as a mineral concrete admixture are analysed. Fly ashes are divided into siliceous ashes and basic ashes.Various application areas of ash-and-slad wastes in construction are considered, the examples of its use are given.

  12. Constitutive model of discontinuous plastic flow at cryogenic temperatures

    CERN Document Server

    Skoczen, B; Bielski, J; Marcinek, D

    2010-01-01

    FCC metals and alloys are frequently used in cryogenic applications, nearly down to the temperature of absolute zero, because of their excellent physical and mechanical properties including ductility. Some of these materials, often characterized by the low stacking fault energy (LSFE), undergo at low temperatures three distinct phenomena: dynamic strain ageing (DSA), plastic strain induced transformation from the parent phase (gamma) to the secondary phase (alpha) and evolution of micro-damage. The constitutive model presented in the paper is focused on the discontinuous plastic flow (serrated yielding) and takes into account the relevant thermodynamic background. The discontinuous plastic flow reflecting the DSA effect is described by the mechanism of local catastrophic failure of Lomer-Cottrell (LC) locks under the stress fields related to the accumulating edge dislocations (below the transition temperature from the screw dislocations to the edge dislocations mode T-1). The failure of LC locks leads to mass...

  13. Effect of shearing, coarse particle and drag reduction additives contents on flow behaviour of dense fly ash-water mixtures

    Czech Academy of Sciences Publication Activity Database

    Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří

    Praha : Institute of Theoretical and Applied Mechanics, 2006, s. 211. ISBN 80-86246-27-2. - (Engineering mechanics). [Engineering Mechanics 2006. Svratka (CZ), 15.05.2006-18.05.2006] R&D Projects: GA AV ČR IAA200600503 Institutional research plan: CEZ:AV0Z20600510 Keywords : Dense ash slurry * effect of shearing * effect of coarse particles * Drag reduction * experimental investigation Subject RIV: BK - Fluid Dynamics

  14. Rheology of fly ashes from coal and biomass co-combustion

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2010-01-01

    The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of vario...... viscosity leading to higher stickiness of the ash particles. Wood co-firing has only minor effects, due to the composition of wood ash and the low percentage of wood in the coal/biomass blend.......The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of various...... coal/biomass blends in a pilot scale pf-boiler. The produced data provide information on the melting of the ash and its flow characteristics, as a function of temperature, which may be used to modify the temperature profile of the boiler in order to avoid slagging. Straw co-firing lowers the ash...

  15. Ash in the Soil System

    Science.gov (United States)

    Pereira, P.

    2012-04-01

    Ash is the organic and inorganic residue produced by combustion, under laboratory and field conditions. This definition is far away to be accepted. Some researchers consider ash only as the inorganic part, others include also the material not completely combusted as charcoal or biochar. There is a need to have a convergence about this question and define clear "what means ash". After the fire and after spread ash onto soil surface, soil properties can be substantially changed depending on ash properties, that can be different according to the burned residue (e.g wood, coal, solid waste, peppermill, animal residues), material treatment before burning, time of exposition and storage conditions. Ash produced in boilers is different from the produced in fires because of the material diferent propertie and burning conditions. In addition, the ash produced in boilers is frequently treated (e.g pelletization, granulation, self curing) previously to application, to reduce the negative effects on soil (e.g rapid increase of pH, mycorrhiza, fine roots of trees and microfauna). These treatments normally reduce the rate of nutrients dissolution. In fires this does not happen. Thus the implications on soil properties are logically different. Depending on the combustion temperature and/or severity, ash could have different physical (e.g texture, wettability) and chemical properties (e.g amount and type of total and leached nutrients) and this will have implications on soil. Ash can increase and decrease soil aggregation, wettablity and water retention, bulk density, runoff and water infiltration. Normally, ash increases soil pH, Electrical Conductivity, and the amount of some basic nutrients as calcium, magnesium, sodium and potassium. However it is also a potential source of heavy metals, especially if ash pH is low. However the effect of ash on soil in space and time depends especially of the ash amount and characteristics, fire temperature, severity, topography, aspect

  16. The study of velocimetry in high temperature flow

    International Nuclear Information System (INIS)

    High temperature flow velocity measurement system is presented. This system employs the ultrasonic buffer rod method and pulsed Doppler method. The buffer rod has a cooling jacket to use the high efficiency room temperature transducer. A numerical simulation is applied to design the optimised buffer rod, and its result shows good agreement with an experiment. For considering ultrasonic velocimetry method, the temperature dependency of sound velocity in the molten glass at the temperature of 1000°C to 1200°C is obtained and its difference is within plus-minus 5 per-cent in the molten borosilicate glass. Therefore, we can apply ultrasonic technique. Using this technique, the velocity, especially the speed of relative moving wall is obtained. (author)

  17. Ash after forest fires. Effects on soil hydrology and erosion

    Science.gov (United States)

    Bodí, Merche B.

    2013-04-01

    Hillslopes were though to be most susceptible to enhanced hydro-geomorphological responses immediately following burning, with susceptibility declining during the first months or years depending on the soil and vegetation recovery. However, Cerdà (1998) found some indices in that immediately after the fire, the thin wettable ash layer that typically covers the ground could absorb rainfall and prevent or delay the onset of overland flow and associated erosion. Therefore the time lag while ash remains on the ground become of crucial importance to protect the soil after a wildfire. The effect of this ash layer was rarely been considered in detail because ash has often been reduced or redistributed by wind or water erosion before the onset of monitoring and thus the data collection typically begun some weeks or month after the fire. The first papers focussed only on ash and its hydrological effects were published by Cerdà and Doerr (2008) and by Woods and Balfour (2008). The results showed that the soil covered with ash indeed reduced and delayed surface runoff, reduced soil splash detachment and produced lower sediment yield compared to bare terrain. However, these findings arose more questions, as for instance: Why in other research there were indices that ash reduces infiltration? what is the mechanism by which why ash reduces overland flow? The research went further with Bodí PhD. First of all, it was crucial the agreement on the fact that the material "ash" is very variable depending on the original vegetation and the type and temperature of combustion. Therefore ash properties are different between wildfires even and within a fire. This is the main reason of its different effects and thus ash not always reduces runoff and sediment yield. In this way, depending on the nature of ash, it can increase overland flow if it is crusted (usually it contains a high content of calcium carbonate), it is water repellent (with high contents of organic carbon and specially

  18. High resolution temperature measurement technique for measuring marine heat flow

    Institute of Scientific and Technical Information of China (English)

    QIN; YangYang; YANG; XiaoQiu; WU; BaoZhen; SUN; ZhaoHua; SHI; XiaoBin

    2013-01-01

    High resolution temperature measurement technique is one of the key techniques for measuring marine heat flow. Basing on Pt1000 platinum resistance which has the characteristics of high accuracy and good stability, we designed a bridge reversal excitation circuit for high resolution temperature measurement. And the deep ocean floor in-situ test results show that: (1) temperature deviation and peak-to-peak resolution of the first version circuit board (V1) are 1.960-1.990 mK and 0.980-0.995 m Kat 1.2-2.7°C, respectively; and temperature deviation and peak-to-peak resolution of the second circuit board (V2) are 2.260mK and 1.130 mK at 1.2-1.3°C, respectively; (2) During the 2012NSFC-IndOcean cruise, seafloor geothermal gradient at Ind2012HF03,-07 and-12 stations (water depth ranges from 3841 to 4541 m) were successfully measured, the values are 59.1,75.1 and 71.6°C/km, respectively. And the measurement errors of geothermal gradient at these three stations are less than 3.0% in terms of the peak-to-peak resolution. These indicate that the high resolution temperature measurement technique based on Pt1000 platinum resistance in this paper can be applied to marine heat flow measurement to obtain high precision geothermal parameters.

  19. Flow and Temperature Fields in Slab Continuous Casting Molds

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to develop super-board and super-thick slabs, the flow and temperature fields were studied in slab continuous casting molds under different practical conditions, such as slab dimensions, with-drawing slab speed, design of nozzles, and superheat temperature. The results showed that it is preferred to incline nozzle bores downwards and the submerged depth of the nozzles is best kept between 250€?300 mm. In addition, the solidified shell is thicker at the wide face than that at the narrow face, while the thin points along the wide face exist both in the center and in the some area toward each respective end.

  20. Experimental Study on Gasification and Ash Fusion Characteristics of Coal with High Ash Fusion Temperatures%高灰熔点煤气化特性及灰渣熔融特性的研究

    Institute of Scientific and Technical Information of China (English)

    乌晓江; 张忠孝; 徐雪元; 刘建斌; 张建文

    2011-01-01

    在0.1-0.2 kg/h小型电加热式常压气流床气化装置上,研究了不同温度、不同O/C物质的量比对高灰熔点煤气化特性和煤灰熔融特性的影响.结果表明:在不同温度下,随着O/C物质的量比增加,CO2体积分数呈线性增加.当O/C物质的量比较低时,H2和CH4体积分数较高;随着O/C物质的量比的增加,合成气中H2和CH4的含量下降较快.在不同温度下,随着O/C物质的量比的增加,碳转化率增加;但当O/C物质的量比达到1.1时,进一步增大O/C物质的量比,则使得炉内煤焦及合成气中可燃气体(CO、H2、CH4等)的燃烧%The effect of temperature and O/C molar ratio on coal gasification and ash fusion characteristics was studied in a 0.1~0.2 kg/h lab-scale electrical entrained-bed coal gasification setup.Results show that the yield of CO2 in syngas increases linearly with rising O/C molar ratio at different temperatures.When O/C molar ratio is at relatively low value,the yields of H2 and CH4 are relatively high,but the yields drop rapidly later on with increasing O/C molar ratio.The carbon conversion increases with growing O/C molar ratio at different temperatures.However,when the O/C molar ratio arrives at 1.1,with further increase of O/C molar ratio,more CO2 and H2O as well as less CO and H2 will be produced due to the increasing combustion share of combustible gases in char and syngas,such as CO,H2 and CH4,which subsequently lead to lower cold gas efficiency.Based on above test conditions,the optimum O/C molar ratio window is found to be 0.9-1.1 while the optimum temperature window is 1 300-1 350 ℃ for Huainan high ash fusion temperature coal with dry ash handling system.

  1. Finite element simulation of temperature dependent free surface flows

    Science.gov (United States)

    Engelman, M. S.; Sani, R. L.

    1985-01-01

    The method of Engelman and Sani (1984) for a finite-element simulation of incompressible surface flows with a free and/or moving fluid interface, such as encountered in crystal growth and coating and polymer technology, is extended to temperature-dependent flows, including the effect of temperature-dependent surface tension. The basic algorithm of Saito and Scriven (1981) and Ruschak (1980) has been generalized and implemented in a robust and versatile finite-element code that can be employed with relative ease for the simulation of free-surface problems in complex geometries. As a result, the costly dependence on the Newton-Raphson algorithm has been eliminated by replacing it with a quasi-Newton iterative method, which nearly retains the superior convergence properties of the Newton-Raphson method.

  2. Diffuse venting at the ASHES hydrothermal field: Heat flux and tidally modulated flow variability derived from in situ time-series measurements

    Science.gov (United States)

    Mittelstaedt, Eric; Fornari, Daniel J.; Crone, Timothy J.; Kinsey, James; Kelley, Deborah; Elend, Mitch

    2016-04-01

    Time-series measurements of diffuse exit-fluid temperature and velocity collected with a new, deep-sea camera, and temperature measurement system, the Diffuse Effluent Measurement System (DEMS), were examined from a fracture network within the ASHES hydrothermal field located in the caldera of Axial Seamount, Juan de Fuca Ridge. The DEMS was installed using the HOV Alvin above a fracture near the Phoenix vent. The system collected 20 s of 20 Hz video imagery and 24 s of 1 Hz temperature measurements each hour between 22 July and 2 August 2014. Fluid velocities were calculated using the Diffuse Fluid Velocimetry (DFV) technique. Over the ˜12 day deployment, median upwelling rates and mean fluid temperature anomalies ranged from 0.5 to 6 cm/s and 0°C to ˜6.5°C above ambient, yielding a heat flux of 0.29 ± 0.22 MW m-2 and heat output of 3.1± 2.5 kW. Using a photo mosaic to measure fracture dimensions, the total diffuse heat output from cracks across ASHES field is estimated to be 2.05 ± 1.95 MW. Variability in temperatures and velocities are strongest at semidiurnal periods and show significant coherence with tidal height variations. These data indicate that periodic variability near Phoenix vent is modulated both by tidally controlled bottom currents and seafloor pressure, with seafloor pressures being the dominant influence. These results emphasize the importance of local permeability on diffuse hydrothermal venting at mid-ocean ridges and the need to better quantify heat flux associated with young oceanic crust.

  3. Experimental studies on pulp and paper mill sludge ash behavior in fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Latva-Somppi, J. [VTT Chemical Technology, Espoo (Finland). Process Technology

    1998-11-01

    reduced. During sludge combustion the largest ash particles, over 200 - 300 lam, were accumulated in the bed due to their size. Ash was also accumulated in the bed as micron-size particles adhered to the sand surface fanning a sintered layer. Bench-scale tests showed that this type of layer, fonmed during bark combustion, initiated bed agglomeration and resulted in defluidization without combustion at 988 deg C. Wirb pulp and paper mill sludges the layer fonnation was not connected to bed agglomeration at the studied temperatures up to 1,000 deg C. Presumably, the bark-derived K species in the layer decreased the ash viscosity and triggered bed agglomeration. Trace elements were not accumulated excessively in the bed. Ash deposits were foamed on the furnace wall above the bed. Ash and sand particles were deposited on the surface roughness probably from the down-flowing particle flux near the wall. Ash sintering densified the structure. Condensed or molten ash species were not detected in the structure. The ash viscosity was lower in the pulp mill sludge resulting in larger deposits than during paper mill sludge firing. Calculations indicate that when the ash viscosity is less than 1,000 - 3,000 Pa s, large ash and sand particles are incorporated in the deposit. (orig.) 121 refs. LIEKKI Research Programme

  4. Fly ash quality and utilization

    Energy Technology Data Exchange (ETDEWEB)

    Barta, L.E.; Lachner, L.; Wenzel, G.B. [Inst. for Energy, Budapest (Hungary); Beer, M.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  5. Coherence imaging for ion temperature and flow measurements in a low-temperature helicon plasma source

    Science.gov (United States)

    Lester, R.; Zhai, Y.; Corr, C.; Howard, J.

    2016-02-01

    This paper describes a coherence imaging system designed for spectroscopic Doppler measurements of ion light in a low-temperature (T e   delay (comparable with the coherence length of the emission line). For these polarization interferometers, this can only be achieved using large thicknesses (100 mm) of birefringent crystal. This poses special design challenges including the application of field-widening techniques and the development of passive thermal stabilization of the optical phase offset. We discuss the measurement principles and the optical design of these systems and present measurements of the line-integrated emissivity, and ion flow and ion temperatures along with tomographic reconstructions of the local values, for a cylindrical low temperature helicon discharge in a linear magnetized device with downstream magnetic mirror. Key results reveal a hollow edge-peaked temperature profile (central temperature  ∼0.1 eV) and sheared rigid-body rotational flows and axial flows which are comparable with the ion thermal speed. The emission line brightness, ion temperature and azimuthal ion flows are all found to increase with increased mirror magnetic field strength.

  6. Experimentally constraining the boundary conditions for volcanic ash aggregation

    Science.gov (United States)

    Kueppers, U.; Auer, B.; Cimarelli, C.; Scolamacchia, T.; Guenthel, M.; Dingwell, D. B.

    2011-12-01

    Volcanic ash is the primary product of various volcanic processes. Due to its size, ash can remain in the atmosphere for a prolonged period of time. Aggregation processes are a first-order influence on the residence time of ash in the atmosphere and its dispersion from the vent. Due to their internal structure, ash aggregates have been classified as ash pellets or accretionary lapilli. Although several concomitant factors may play a role during aggregation, there is a broad consensus that both 1) particle collision and 2) humidity are required for particles to aggregate. However, direct observation of settling aggregates and record of the boundary conditions favourable to their formation are rare, therefore limiting our understanding of the key processes that determine ash aggregates formation. Here, we present the first results from experiments aimed at reproducing ash aggregation by constraining the required boundary conditions. We used a ProCell Lab System of Glatt Ingenieurtechnik GmbH that is conventionally used for food and chemical applications. We varied the following parameters: 1) air flow speed [40-120 m3/h], 2) air temperature [30-60°C], 3) relative humidity [20-50 %], and 4) liquid droplets composition [water and 25% water glass, Na2SiO3]. The starting material (125-90 μm) is obtained by milling natural basaltic lapilli (Etna, Italy). We found that the experimental duration and the chosen conditions were not favourable for the production of stable aggregates when using water as spraying liquid. Using a 25% water-glass solution as binder we could successfully generate and investigate aggregates of up to 2 mm size. Many aggregates are spherical and resemble ash pellets. In nature, ash pellets and accretionary lapilli are the product of complex processes taking place at very different conditions (temperature, humidity, ash concentration, degree of turbulence). These experiments shed some first light on the ash agglomeration process for which direct

  7. Studies on digestion and absorption in the intestines of growing pigs. 2. Measurements of the flow of dry matter, ash and water.

    Science.gov (United States)

    Low, A G; Partridge, I G; Sambrook, I E

    1978-05-01

    1. Digesta were collected from twenty-three pigs, initially of 30 kg live weight, and fitted with single Ash re-entrant cannulas in either the duodenum, jejunum or ileum. A further twenty-four pigs were used in a conventional digestibility trial. 2. The diets contained: barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut (diet SSG) or casein (diet SSC). 3. The flow-rates of dry matter (DM), ash and water were measured hourly in the duodenum and jejunum, and every 6 h in the ileum during 24 h collection periods. Faeces were collected during 5 d periods. 4. Marked increases in the flow rates of each of the digesta components after feeding each diet were observed in the duodenum and jejunum, but not in the ileum. The total flow in 24 h periods was much lower in the ileum than at the other sites. 5. Values for the ratio, DM output: intake for DM outputs from the duodenal, jejunal or ileal cannulas, and in faeces, in 24 h periods were respectively 0.94, 0.81, 0.28 and 0.22 for diet BWF; 0.96, 0.76, 0.20 and 0.15 for diet SSG; 0.96, 0.73, 0.08 and 0.04 for diet SSC. The corresponding values for ash were: 1.47, 1.65, 0.74 and 0.53 for diet BWF; 1.28, 1.34, 0.59 and 0.51 for diet SSG; 1.63, 1.35, 0.50 and 0.26 for diet SSC. The corresponding values for water were: 3.49, 3.41, 0.88 and 0.18 for diet BWF, 2.75, 2.80, 0.80 and 0.08 for diet SSG and 2.61, 1.87, 0.23 and 0.01 for diet SSC. PMID:638121

  8. Can ash clog soil pores?

    Science.gov (United States)

    Stoof, Cathelijne; Stoof, Cathelijne; Gevaert, Anouk; Gevaert, Anouk; Baver, Christine; Baver, Christine; Hassanpour, Bahareh; Hassanpour, Bahareh; Morales, Veronica; Morales, Veronica; Zhang, Wei; Zhang, Wei; Martin, Deborah; Martin, Deborah; Steenhuis, Tammo; Steenhuis, Tammo

    2015-04-01

    Wildfire can greatly increase a landscape's vulnerability to flooding and erosion events, and ash is thought to play a large role in controlling runoff and erosion processes after wildfire. Although ash can store rainfall and thereby reduce runoff and erosion for a limited period after wildfires, it has also been hypothesized to clog soil pores and reduce infiltration. Several researchers have attributed the commonly observed increase in runoff and erosion after fire to the potential pore-clogging effect of ash. Evidence is however incomplete, as to date, research has solely focused on identifying the presence of ash in the soil, with the actual flow processes associated with the infiltration and pore-clogging of ash remaining a major unknown. In several laboratory experiments, we tested the hypothesis that ash causes pore clogging to the point that infiltration is hampered and ponding occurs. We first visualized and quantified pore-scale infiltration of water and ash in sand of a range of textures and at various infiltration rates, using a digital bright field microscope capturing both photo and video. While these visualization experiments confirm field and lab observation of ash washing into soil pores, we did not observe any clogging of pores, and have not been able to create conditions for which this does occur. Additional electrochemical analysis and measurement of saturated hydraulic conductivity indicate that pore clogging by ash is not plausible. Electrochemical analysis showed that ash and sand are both negatively charged, showing that attachment of ash to sand and any resulting clogging is unlikely. Ash also had quite high saturated conductivity, and systems where ash was mixed in or lying on top of sand had similarly high hydraulic conductivity. Based on these various experiments, we cannot confirm the hypothesis that pore clogging by ash contributes to the frequently observed increase in post-fire runoff, at least for the medium to coarse sands

  9. Temperature distribution in a low-temperature plasma flow from a self-reversed spectral profile

    International Nuclear Information System (INIS)

    A method is reported for restoring the temperature space distribution using the profile of a spectral line radiated in a low-temperature plasma flow. The main advantage of the method consists in using one-directional diagnostics. The calculations are based on the following assumptions: (a) the temperature distribution T(x) is symmetric; (b) it is represented by an analytical form with few parameters; (c) there is LTE in the plasma and the density of the emitting atoms is a known function of the temperature. A corresponding computer code for solving this inverse problem is realized. The model computation shows that the procedure of restoring T(x) is satisfactorily converging to a well defined solution. The method is used for diagnostics of a combustion products' plasma flow with an alkali seed. Typical parameters are: temperature on the axis 2500 K, width of the channel 0.16 m, alkali atom density 1021 m-3, flow velocity several hundreds m/s. The measurements are performed on the spectral doublet of potassium 766.5/769.9 nm. The temperature distributions T(x) obtained by solving the inverse problem are compared with T(x) calculated on the base of the theory of a two-dimensional turbulent boundary layer. (author)

  10. Ash melting behavior by Fourier transform infrared spectroscopy

    Institute of Scientific and Technical Information of China (English)

    LI Han-xu; QIU Xiao-sheng; TANG Yong-xin

    2008-01-01

    A Fourier Transform Infrared Spectroscopic (FTIR) method involving a Fe2O3 flux was used to learn how China's coal ash melts. The relationship between ash fusion temperature and chemical composition, as well as the effects of Fe2O3 flux on the ash fusion temperature were studied. The relationship between ash fusion temperature and chemical composition, mineralogical phases and functional groups was analyzed with the FTIR method. The results show that the ash fusion temperature is related to the location and transmittance of certain absorption peaks, which is of great significance for the study of ash behavior.

  11. Effect of sintering temperature on mechanical behaviour and bioactivity of sol-gel synthesized bioglass-ceramics using rice husk ash as a silica source

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, J.P., E-mail: jyotiprakash_nitrkl@rediffmail.com [Department of Ceramic Engineering, National Institute of Technology, Rourkela, Odisha 769008 (India); Bera, J., E-mail: bera@rediffmail.com [Department of Ceramic Engineering, National Institute of Technology, Rourkela, Odisha 769008 (India)

    2010-11-01

    Bioglass-ceramics with SiO{sub 2}-Na{sub 2}O-CaO composition was prepared by sol-gel method using rice husk ash as a silica source. Material was sintered at different temperatures ranging from 900 to 1050 deg. C for 2 h. Phase-formation behaviour, densification characteristics, and mechanical strength of glass-ceramics were investigated. The material sintered at 1000 deg. C showed a good mechanical strength. Mechanical properties were correlated with microstructural features. Both in vitro bioactivity and biodegradability of sintered material were investigated by incubating in simulated body fluid and Tris buffer solution, respectively. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to investigate the surface deposition during body fluid incubation. Both bioactivity and degradability decreased with increase in sintering temperature.

  12. Temperature-gradient and heat flow data, Grass Valley, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, James B.; Gardner, Murray C.

    1979-11-01

    A series of 16 shallow and intermediate-depth temperature-gradient holes were drilled for Sunoco Energy Development Co. in Grass Valley, Pershing County, Nevada, on leases held by Aminoil USA, Inc., under the cost-sharing industry-linked program of the Department of Energy. Thirteen shallow (85-152 m) and 3 intermediate-depth (360-457 m) holes were completed and logged during the period June through September, 1979. The locations of these holes and of pre-existing temperature-gradient holes are shown on plate 1. This report constitutes a final data transmittal and disclosure of results. The drilling subcontractor was Southwest Drilling and Exploration, Inc. of Central, Utah. They provided a Gardner-Denver 15W rig, a 3-man crew, and supporting equipment. A l l holes were drilled with mud as the circulating medium. Drilling histories for each hole are summarized in table 1. GeothermEx, Inc. performed on-site geological descriptions of the cuttings; obtained several temperature profiles for each hole, including an equilibrium profile taken 23 days or more after cessation of drilling; selected samples for thermal conductivity measurements; integrated temperature, temperature-gradient, and heat-flow data obtained in this project with published values; and prepared this report.

  13. The Wilson Flow and the finite temperature phase transition

    OpenAIRE

    Wandelt, Michèle; Knechtli, Francesco; Günther, Michael

    2016-01-01

    We consider the determination of the finite temperature phase transition in the Yang--Mills SU(3) gauge theory. We compute the difference of the spatial and temporal energy density at a physical Wilson flow time. This difference is zero in the confined phase and becomes non zero in the deconfined phase. We locate the phase transition by using a new technique based on an exponential smoothing spline. This method is an alternative to the determination of the phase transition based on the Polyak...

  14. The Wilson Flow and the finite temperature phase transition

    CERN Document Server

    Wandelt, Michèle; Günther, Michael

    2016-01-01

    We consider the determination of the finite temperature phase transition in the Yang--Mills SU(3) gauge theory. We compute the difference of the spatial and temporal energy density at a physical Wilson flow time. This difference is zero in the confined phase and becomes non zero in the deconfined phase. We locate the phase transition by using a new technique based on an exponential smoothing spline. This method is an alternative to the determination of the phase transition based on the Polyakov loop susceptibility and can also be used with dynamical fermions.

  15. Increase of body surface temperature and blood flow by theanine

    International Nuclear Information System (INIS)

    Suntheanine (Taiyo Kagaku Co.: Theanine) is the trade name for L-theanine which is a unique amino acid found almost solely in tea plants, responsible for the exotictaste of green tea. We investigated the effects of relate to relaxation, improves the taste of processed foods, radiation sensitization, and increase of body surface temperature in vivo study. The results of the present study confirmed, (1) Suntheanine is incorporated into the brain and induces the emission of α -waves an induced of relaxation. (2) Body surface temperature and blood flow on skin were increased after administration of Suntheanine. (3) There was effects of radiation sensitization in whole body irradiation of X-rays after Suntheanine IP injection on C3H mice. (4) Acute toxicity, subacute toxicity and mutagen testconfirm the safety Suntheanine in this study

  16. Increase of body surface temperature and blood flow by theanine

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Takeo; Noguchi, Kenichi; Ando, Satoshi [Suzuka, Univ. of Medical Science, Suzuka (Japan)] [and others

    2002-07-01

    Suntheanine (Taiyo Kagaku Co.: Theanine) is the trade name for L-theanine which is a unique amino acid found almost solely in tea plants, responsible for the exotictaste of green tea. We investigated the effects of relate to relaxation, improves the taste of processed foods, radiation sensitization, and increase of body surface temperature in vivo study. The results of the present study confirmed, (1) Suntheanine is incorporated into the brain and induces the emission of {alpha} -waves an induced of relaxation. (2) Body surface temperature and blood flow on skin were increased after administration of Suntheanine. (3) There was effects of radiation sensitization in whole body irradiation of X-rays after Suntheanine IP injection on C3H mice. (4) Acute toxicity, subacute toxicity and mutagen testconfirm the safety Suntheanine in this study.

  17. Effects of curing temperature and NaOH addition on hydration and strength development of clinker-free CKD-fly ash binders

    International Nuclear Information System (INIS)

    Effects of curing temperature and NaOH addition on hydration and strength development of cement kiln dust (CKD)-fly ash (FA) binders were investigated. Pastes made with 50% CKD and 50% FA, having 0, 2, and 5% NaOH addition, and cured at temperatures of 24, 38, and 50 deg. C were evaluated. The hydration products of the binders were examined by thermogravimetric analysis (TGA) and X-ray diffraction (XRD) tests. The results indicate that the major crystalline hydration product of the CKD-FA binders is ettringite, and the ettringite is stable in the CKD-FA system at age over 100 days. Curing at elevated temperature is more effective for CKD-FA binder strength improvement than NaOH addition, the later often depressing ettringite formation in a CKD-FA system. At a proper curing temperature (38 deg. C), addition of a small amount of NaOH (2%) may increase CKD-FA binder strength; while at a high curing temperature (50 deg. C), addition of NaOH (2%) may reduce the binder strength

  18. Effect of temperature on the hydration process and strength development in blends of Portland cement and activated coal gangue or fly ash

    Institute of Scientific and Technical Information of China (English)

    Pei-ming WANG; Xian-ping LIU

    2011-01-01

    This paper describes the results of an investigation into the effect of the variation of curing temperatures between 0 and 60 ℃ on the hydration process,pore structure variation,and compressive strength development of activated coal gangue-cement blend (ACGC).Hardened ACGC pastes cured for hydration periods from 1 to 360 d were examined using the non-evaporable water method,thermal analysis,mercury intrusion porosimetry,and mechanical testing.To evaluate the specific effect of activated coal gangue (ACG) as a supplementary cementing material (SCM),a fly ash-cement blend (FAC) was used as a control.Results show that raising the curing temperature accelerates pozzolanic reactions involving the SCMs,increasing the degree of hydration of the cement blends,and hence increasing the rate of improvement in strength.The effect of curing temperature on FAC is greater than that on ACGC.The pore structure of the hardened cement paste is improved by increasing the curing temperature up to 40 ℃,but when the curing temperature reaches 60 ℃,the changing nature of the pore structure leads to a decrease in strength.The correlation between compressive strength and the degree of hydration and porosity is linear in nature.

  19. EDU 626 ASH

    OpenAIRE

    NARESH 40 course tutorial/tutorialoutlet

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com     Product Description EDU 626 Week 1 Research Topic (Ash) EDU 626 Week 2 Annotated Bibliography (Ash) EDU 626 Week 2 Critical Thinking Questions (Ash) EDU 626 Week 3 Procedures or Methods (Ash) EDU 626 Week 4 Critical Thinking Questions (Ash) EDU 626 Week 5 Critical Thinking Questions (Ash) EDU 626 Week 6 Final Paper (Ash)  

  20. The effects of temperatures on the pebble flow in a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    The core of a pebble bed high temperature reactor (PBHTR) moves during operation, a feature which leads to better fuel economy (online refueling with no burnable poisons) and lower fuel stress. The pebbles are loaded at the top and trickle to the bottom of the core after which the burnup of each is measured. The pebbles that are not fully burned are recirculated through the core until the target burnup is achieved. The flow pattern of the pebbles through the core is of importance for core simulations because it couples the burnup distribution to the core temperature and power profiles, especially in cores with two or more radial burnup 'zones '. The pebble velocity profile is a strong function of the core geometry and the friction between the pebbles and the surrounding structures (other pebbles or graphite reflector blocks). The friction coefficient for graphite in a helium environment is inversely related to the temperature. The Thorium High Temperature Reactor (THTR) operated in Germany between 1983 and 1989. It featured a two-zone core, an inner core (IC) and outer core (OC), with different fuel mixtures loaded in each zone. The rate at which the IC was refueled relative to the OC in THTR was designed to be 0.56. During its operation, however, this ratio was measured to be 0.76, suggesting the pebbles in the inner core traveled faster than expected. It has been postulated that the positive feedback effect between inner core temperature, burnup, and pebble flow was underestimated in THTR. Because of the power shape, the center of the core in a typical cylindrical PBHTR operates at a higher temperature than the region next to the side reflector. The friction between pebbles in the IC is lower than that in the OC, perhaps causing a higher relative flow rate and lower average burnup, which in turn yield a higher local power density. Furthermore, the pebbles in the center region have higher velocities than the pebbles next to the side reflector due to the

  1. Influence of moisture content and temperature on degree of carbonation and the effect on Cu and Cr leaching from incineration bottom ash.

    Science.gov (United States)

    Lin, Wenlin Yvonne; Heng, Kim Soon; Sun, Xiaolong; Wang, Jing-Yuan

    2015-09-01

    This study investigated the influence of moisture content and temperature on the degree of carbonation of municipal solid waste (MSW) incineration bottom ash (IBA) from two different incineration plants in Singapore. The initial rate of carbonation was affected by the nominal moisture content used. Carbonation temperature seemed to play a part in changing the actual moisture content of IBA during carbonation, which in turn affected the degree of carbonation. Results showed that 2h of carbonation was sufficient for the samples to reach a relatively high degree of carbonation that was close to the degree of carbonation observed after 1week of carbonation. Both Cu and Cr leaching also showed significant reduction after only 2h of carbonation. Therefore, the optimum moisture content and temperature were selected based on 2h of carbonation. The optimum moisture content was 15% for both incineration plants while the optimum temperature was different for the two incineration plants, at 35°C and 50°C. The effect on Cu and Cr leaching from IBA after accelerated carbonation was evaluated as a function of carbonation time. Correlation coefficient, Pearson's R, was used to determine the dominant leaching mechanism. The reduction in Cu leaching was found to be contributed by both formation of carbonate mineral and reduction of DOC leaching. On the other hand, Cr leaching seemed to be dominantly controlled by pH. PMID:26077229

  2. Corrosion of high temperature resisting alloys exposed to heavy fuel ash; Corrosion de aleaciones resistentes a altas temperaturas expuestas a ceniza de combustoleo pesado

    Energy Technology Data Exchange (ETDEWEB)

    Wong Moreno, Adriana del Carmen

    1998-03-01

    The objective of the performed research was to study the degradation process by high temperature corrosion of alloys exposed to heavy fuel oil ashes through a comparative experimental evaluation of its performance that allowed to establish the mechanisms involved in the phenomenon. The experimentation carried out involved the determination of the resistance to the corrosion of 14 alloys of different type (low and medium alloy steels, ferritic and austenitic stainless steels, nickel base alloys and a FeCrAl alloy of type ODS) exposed to high temperatures (580 Celsius degrees - 900 Celsius degrees) in 15 ash deposits with different corrosive potential, which were collected in the high temperature zone of boilers of thermoelectric power stations. The later studies to the corrosion tests consisted of the analysis by sweeping electron microscopy supported by microanalysis of the corroded probes, with the purpose of determining the effect of Na, V and S on the corrosivity of the ash deposits and the effect of the main alloying elements on the corrosion resistance of the alloys. Such effects are widely documented to support the proposed mechanisms of degradation that are occurring. The global analysis of the generated results has allowed to propose a model to explain the global mechanism of corrosion of alloys exposed to the high temperatures of ash deposits. The proposed model, complements the processed one by Wilson, widely accepted for fused vanadates, as far as on one hand, it considers the effect of the sodium sulfate presence (in addition to the vanadium compounds) in the deposits, and on the other hand, it extends it to temperatures higher than the point of fusion of constituent vanadium compounds of the deposits. Both aspects involve considering the roll that the process of diffusion of species has on the degradation and the capacity of protection of the alloy. The research performed allowed to confirm what the Wilson model had established for deposits with high

  3. Utilization of ash fractions from alternative biofuels used in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaisen, L.; Hinge, J.; Christensen, I. (Danish Technological Inst., Aarhus (Denmark)); Dahl, J. (Force Technology, Broendby (Denmark)); Arendt Jensen, P. (DTU-CHEC, Kgs. Lyngby (Denmark)); Soendergaard Birkmose, T. (Dansk Landbrugsraadgivning, Landscentret, Aarhus (Denmark)); Sander, B. (DONG Energy, Fredericia (Denmark)); Kristensen, O. (Kommunekemi A/S, Nyborg (Denmark))

    2008-07-15

    It is expected, that demand for the traditional biomass resources wood and straw will increase over the next years. In other projects a number of agro industrial waste products has been tested and characterized as fuels for power plants. The annual production in Denmark of these fuels is estimated at roughly 400.000 tons of Dry Matter per year, so the potential is substantial. The agro industrial biomass products include: Grain screening waste, pea shells, soy waste, cocoa waste, sugar beet waste, sunflower waste, shea waste, coffee waste, olive waste, rice shell waste, potato waste, pectin waste, carrageen waste, tobacco waste, rape seed waste and mash from breweries. In the PSO project 5075, 5 different types of fuel pellets was produced, which were rendered suitable for combustion in power plants. In this project, ash is produced from the above mentioned 5 mixtures together with another 2 mixtures produced especially for this project. From the 5 mixtures from PSO 5075, ash is produced at Danish Technological Institute's slag analyzer. These ash products are rendered comparable to ash from grate fired boilers at power plants. The ash/slag from the combustion in the slag analyzer was then grinded - thus resulting in a total of 5 ash products. At DTU CHEC's Entrained Flow Reactor, ash products from the 5+2 mixtures were produced. These ash products are rendered comparable to ash produced form suspension fired boilers at power plants. For each of the 7 mixtures, bottom-, cyclone and filter ash was taken out separately resulting in a total of 21 ash samples. The produced ashes have been evaluated for their properties as directly applied fertilizer. Furthermore, scenarios have been set up to assess the feasibility in producing artificial fertilizer from the ash products, based on known processes. In the main components the content of Na, S, Cl and K is significantly higher in filter ashes, whereas the content of Mg, Al, Si and Ca is significantly lower. The

  4. Coherent structures in ion temperature gradient turbulence-zonal flow

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Singh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kaw, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Gürcan, Ö. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); CMTFO and CASS, University of California, San Diego, California 92093 (United States)

    2014-10-15

    Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m = n = 0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.

  5. Surface modification of oil fly ash and its application in selective capturing of carbon dioxide

    Science.gov (United States)

    Yaumi, Ali L.; Hussien, Ibnelwaleed A.; Shawabkeh, Reyad A.

    2013-02-01

    Oil fly ash from power generation plants was activated with 30% NH4OH and used for selective adsorption of carbon dioxide from CO2/N2 mixture. The treated samples were characterized for their surface area, morphology, crystalline phase, chemical composition and surface functional groups. Energy dispersive X-ray analysis showed an increase in the carbon contents from 45 to 73 wt% as a result of leaching out metal oxides. XRD proved that chemical activation of ash resulted in diminishing of major crystalline phases of zeolite, and other alumino-silicates leaving only quartz and mullite. BET analysis showed an increase in surface area from 59 to 318 m2/g after chemical activation and the pore volume increased from 0.0368 to 0.679 cm3/g. This increase in pore volume is supported by the results of SEM, where more micropores were opened with well-defined particle sizes and porous structure. The TGA of the treated fly ash showed stability at higher temperature as the weight loss decreased with increasing temperature. For treated ash, the FTIR displayed new peaks of amine functional group. The treated ash was used for the removal of CO2 from CO2/N2 mixture and the maximum adsorption/capturing capacity was found to be 240 mg/g. This capacity increases with increase in initial gas concentration, inlet flow rate and temperature suggesting the endothermic nature of the interaction between the gas molecules and the surface of the ash.

  6. Triboelectrostatic separation of unburned carbon from fly ash for ash recycling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Keun; Kim, Seong Chan; Son, Nag Won; Kim, Doo Hyun; Oh, Jung Geun [Pusan National University, Pusan (Korea, Republic of)

    1997-09-30

    Fly ash from a coal-fired power plant is produced approximately 3 million tons in 1996 and causes the serious environmental problem due to the disposal in the ash pond. Fly ash is an accepted additive in concrete where it adds strength, sulfate resistance and reduced cost, provided acceptable levels of unburned carbon are maintained. This paper describes to investigate the technical feasibility of a dry triboelectrostatic process to separate unburned carbon from fly ash into economically valuable products. Particles of unburned carbon and fly ash can be imparted positive and negative surface charges, respectively, with a copper tribocharger due to differences in the work function values of the particles and the tribocharger, and can be separated by passing them through an external electric field. A laboratory scale separation system consists of a screw feeder for ash supply, a tribocharger, vertical collecting copper plates, power supplies, a flow meter, and a fan. Separation tests taking into account separation efficiency and ash recovery showed that fly ash recovery was strongly dependent on the tribocharger geometry, electric field strength, fly ash size, and ash feeding rate. Optimal separation conditions were fly ash size less than 125 {mu}m and electric field strength of 200 kV/m. Over 80% of the fly ash with 7% loss on ignition was recovered at carbon contents less than 3%. (author). 6 refs., 2 tabs., 9 figs.

  7. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    OpenAIRE

    Xueping Gao; Guangning Li; Yunpeng Han

    2014-01-01

    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was de...

  8. Incineration ash conditioning processes

    International Nuclear Information System (INIS)

    Incinerable wastes consist of the following standard composition corresponding to projected wastes from a future mixed oxide fuel fabrication plant with an annual throughput of 1700 kg (i.e. 5.7 m3) of ashes produced by the incineration facility: . 50% polyvinyl chloride (glove box sleeves), . 5% polyethylene (bags), . 35% rubber (equal amounts of latex and neoprene), . 10% cellulose (equal amounts of cotton and cleansing tissues). The work focused mainly on compaction by high-temperature isostatic pressing, is described in some detail with the results obtained. An engineering study was also carried out to compare this technology with two other ash containment processes: direct-induction (cold crucible) melting and cement-resin matrix embedding. Induction melting is considerably less costly than isostatic pressing; the operating costs are about 1.5 times higher than for cement-resin embedding, but the volume reduction is nearly 3 times greater

  9. Temperature and high pressure effects on choked flow in the microchannel

    Science.gov (United States)

    Parahovnik, Anatoly; Fraiman, Leonid; Rosinsky, Israel; Yossifon, Gilad

    2016-02-01

    We studied the choked flow behavior of gas flow in a single microchannel at inlet pressures of up to 2.2 MPa. Fair agreement was obtained between the basic compressible flow theory, known as Fanno flow, numerical simulations, and experiments for the mass flow rate dependency on the inlet pressure. Investigation of the effect of varying the inlet temperature on the choked flow behavior revealed that the power law scaling of the maximum flow rate on the temperature varies with inlet pressure. This was suggested, using numerical simulations, to be a result of heat loss to the environment.

  10. Deposit formation in a full-scale pulverized wood-fired power plant with and without coal fly ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt;

    2013-01-01

    Ash transformation and deposition in a pulverized wood-fired power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was investigated by using an advanced deposit probe system at two different boiler locations with flue gas...... ash) to the boiler, these alkali species were effectively removed both in the fly ash and in the deposits, and a more frequent shedding of the deposits was observed. The results imply that coal fly ash can be an effective additive to reduce ash deposition and corrosion problems in a pulverized wood-fired...... at the low-temperature location showed a slow initial build-up and a stable mass of deposits after approximately 1-5 h. The deposits collected during pulverized wood combustion contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of coal fly ash (~4 times of the mass flow of wood...

  11. High energy sodium based room temperature flow batteries

    Science.gov (United States)

    Shamie, Jack

    As novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load level the intermittent nature of these energy sources. Energy storage is achieved by converting electrical energy into another form of energy. Batteries have many properties that are attractive for energy storage including high energy and power. Among many different types of batteries, redox flow batteries (RFBs) offer many advantages. Unlike conventional batteries, RFBs store energy in a liquid medium rather than solid active materials. This method of storage allows for the separation of energy and power unlike conventional batteries. Additionally flow batteries may have long lifetimes because there is no expansion or contraction of electrodes. A major disadvantage of RFB's is its lower energy density when compared to traditional batteries. In this Thesis, a novel hybrid Na-based redox flow battery (HNFB) is explored, which utilizes a room temperature molten sodium based anode, a sodium ion conducting solid electrolyte and liquid catholytes. The sodium electrode leads to high voltages and energy and allows for the possibility of multi-electron transfer per molecule. Vanadium acetylacetonate (acac) and TEMPO have been investigated for their use as catholytes. In the vanadium system, 2 electrons transfers per vanadium atom were found leading to a doubling of capacity. In addition, degradation of the charged state was found to be reversible within the voltage range of the cell. Contamination by water leads to the formation of vanadyl acetylacetonate. Although it is believed that vanadyl complex need to be taken to low voltages to be reduced back to vanadium acac, a new mechanism is shown that begins at higher voltages (2.1V). Vanadyl complexes react with excess ligand and protons to reform the vanadium complex. During this reaction, water is reformed leading to the continuous cycle in which vanadyl is formed and then reduced back

  12. Removal of uranium from simulated fly ash by chloride volatilization method

    International Nuclear Information System (INIS)

    Fly ash is generated from LWR nuclear power plant as a low-level waste, which is contaminated with a small amount of radioactive materials, composed mainly of uranium oxide. The constituents of the fly ash are similar to those of the ore; the major components of the ash are oxides of silicon, aluminum, sodium, magnesium, zinc, iron sodium and uranium. In this study, removal of uranium from the simulated fly ash, of which composition was U3O8: 10, CaO:25, SiO2: 25, Al2O3: 20, MgO: 10, ZnO:5, Fe2O3: 3 and Na2CO3: 2 wt%, by chloride volatilization method was examined. The simulated fly ash was chlorinated by the same manner as the dry way processing for the ore; namely, the ash was heated in a flow of chlorine in the presence of carbon at high temperatures. In the case of volatilization of uranium from U3O8 and a simulated fly ash by chlorination using chlorine and carbon, it was seen that uranium of both samples showed similar volatilization behaviour: The volatilization ratio of uranium (VU) increased with increasing temperature from 800 to 1100 C. The VU value attained 99.9% at 1100 C. Iron, silicon and zinc showed similar behaviour to uranium, namely, they vaporized completely. The volatilization ratio of aluminum, magnesium and sodium were still high in a range 80-90%. The volatilization ratio of calcium was ∼40% under the same chlorination condition, though it changed to chloride. For recovery of uranium from fly ash by chlorination using chlorine in the presence of carbon, high volatilization ratio of uranium can be achieved at high temperatures. Volatilization ratio of other components also increases, which decreases the amount of decontaminated residue resulting in the reducing of decontamination effect. Selection of heating condition is important. (author)

  13. Agglomeration behaviour of high ash Indian coals in fluidized bed gasification pilot plant

    International Nuclear Information System (INIS)

    Although gasification of high ash Indian coals is gaining importance, the resultant uncertainties associated with agglomerate formation are still unresolved. To address this, a suitable pilot scale Fluidized Bed Gasifier was utilized in this study. Stabilized operating conditions in terms of coal feed rate, air feed rate, bed temperature, etc., already identified for maximum possible carbon conversion, were maintained in all experiments and the steam flow rate was only varied. Though the ash fusion temperature of the coals were above 1200 °C, agglomerate was formed during gasification at 950 °C with ‘steam to coal ratio’ less than 0.15 (kg/kg). On increasing this ratio above 0.2 local heat-concentration and agglomeration could be avoided with certainty. Chemical composition alone was not sufficient to explain the relative strength of ash-agglomerates. Compositional variation and state of iron within the matrix were assessed through SEM-EDX and electron paramagnetic resonance (EPR) study, respectively. The probing also required the ash-loading and iron-loading factors to be freshly defined in the context of gasification. Localized heat, large compositional variation, presence of iron in Fe2+ state, ash-loading/iron-loading factors influenced intensity of agglomerate formation. Finally, low temperature agglomerate formation was explained by SiO2–Al2O3–FeO phase diagram. - Highlights: • Pilot plant studies on agglomerate formation during high ash coal gasification. • AFT, chemical analysis of coal ash could not give proper indication. • Ash-/iron-loading factors, compositional variation, Fe2+ leads to agglomeration. • Steam to coal ratio was controlled judiciously to avoid agglomeration. • Cause for agglomeration investigated in depth and remedial adjustment was focused

  14. Effect of temperature on the durability of class C fly ash belite cement in simulated radioactive liquid waste: synergy of chloride and sulphate ions.

    Science.gov (United States)

    Guerrero, A; Goñi, S; Allegro, V R

    2009-06-15

    The durability of class C fly ash belite cement (FABC-2-W) in simulated radioactive liquid waste (SRLW) rich in a mixed sodium chloride and sulphate solution is presented here. The effect of the temperature and potential synergic effect of chloride and sulfate ions are discussed. This study has been carried out according to the Koch-Steinegger test, at the temperature of 20 degrees C and 40 degrees C during a period of 180 days. The durability has been evaluated by the changes of the flexural strength of mortar, fabricated with this cement, immersed in a simulated radioactive liquid waste rich in sulfate (0.5M), chloride (0.5M) and sodium (1.5M) ions--catalogued like severely aggressive for the traditional Portland cement--and demineralised water, which was used as reference. The reaction mechanism of sulphate, chloride and sodium ions with the mortar was evaluated by scanning electron microscopy (SEM), porosity and pore-size distribution, and X-ray diffraction (XRD). The results showed that the chloride binding and formation of Friedel's salt was inhibited by the presence of sulphate. Sulphate ion reacts preferentially with the calcium aluminate hydrates forming non-expansive ettringite which precipitated inside the pores; the microstructure was refined and the mechanical properties enhanced. This process was faster and more marked at 40 degrees C. PMID:19056176

  15. On The Temperature Field of a Viscous Reacting Flow Near a Moving Wall with Thermal Radiation

    OpenAIRE

    B.I. Olajuwon; Ayeni, R. O.

    2005-01-01

    We examine the temperature field of a viscous reacting flow near a moving wall with thermal radiation. Of particular interest is the effect of thermal radiation parameter and the Frank-kamenetskii parameter on the flow.

  16. Adhesion Strength of Biomass Ash Deposits

    DEFF Research Database (Denmark)

    Laxminarayan, Yashasvi; Jensen, Peter Arendt; Wu, Hao;

    2015-01-01

    This study investigates the shear adhesion strength of biomass ash deposits on superheater tubes. Artificial biomass ash deposits were prepared on superheater tubes and sintered in an oven at temperatures up to 1000°C. Subsequently, the deposits were sheared off with the help of an electrically...

  17. Temperature and flow rate effects on mass median diameters of thermally generated malathion and naled fogs.

    Science.gov (United States)

    Brown, J R; Chew, V; Melson, R O

    1993-06-01

    The effects of temperature and flow rate on mass median diameters (mmds) of thermally generated aerosol clouds were studied. Number 2 fuel oil alone, undiluted and diluted malathion 91, and undiluted naled were examined. There was a significant flow rate x temperature interaction on the mmds of diluted malathion fogs: i.e., differences among flow rates depended on temperature and vice versa. PMID:8350082

  18. Magnetic properties in an ash flow tuff with continuous grain size variation: a natural reference for magnetic particle granulometry

    Science.gov (United States)

    Till, J.L.; Jackson, M.J.; Rosenbaum, J.G.; Solheid, P.

    2011-01-01

    The Tiva Canyon Tuff contains dispersed nanoscale Fe-Ti-oxide grains with a narrow magnetic grain size distribution, making it an ideal material in which to identify and study grain-size-sensitive magnetic behavior in rocks. A detailed magnetic characterization was performed on samples from the basal 5 m of the tuff. The magnetic materials in this basal section consist primarily of (low-impurity) magnetite in the form of elongated submicron grains exsolved from volcanic glass. Magnetic properties studied include bulk magnetic susceptibility, frequency-dependent and temperature-dependent magnetic susceptibility, anhysteretic remanence acquisition, and hysteresis properties. The combined data constitute a distinct magnetic signature at each stratigraphic level in the section corresponding to different grain size distributions. The inferred magnetic domain state changes progressively upward from superparamagnetic grains near the base to particles with pseudo-single-domain or metastable single-domain characteristics near the top of the sampled section. Direct observations of magnetic grain size confirm that distinct transitions in room temperature magnetic susceptibility and remanence probably denote the limits of stable single-domain behavior in the section. These results provide a unique example of grain-size-dependent magnetic properties in noninteracting particle assemblages over three decades of grain size, including close approximations of ideal Stoner-Wohlfarth assemblages, and may be considered a useful reference for future rock magnetic studies involving grain-size-sensitive properties.

  19. Characterization of ashes from biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, F.J.; Hansen, L.A. [Technical Univ. of Denmark. Dept. of Chemical Engineering (Denmark); Soerensen, H.S. [Geological Survey of Denmark and Greenland (Denmark); Hjuler, K. [dk-TEKNIK. Energy and Environment (Denmark)

    1998-02-01

    One motivation for initiating the present project was that the international standard method of estimating the deposit propensity of solid fuels, of which a number of variants exist (e.g. ISO, ASTM, SD, DIN), has shown to be unsuitable for biomass ashes. This goal was addressed by the development of two new methods for the detection of ash fusibility behaviour based on Simultaneous Thermal Analysis (STA) and High Temperature Light Microscopy (HTLM), respectively. The methods were developed specifically for ashes from biofuels, but are suitable for coal ashes as well. They have been tested using simple salt mixtures, geological standards and samples from straw CHP and coal-straw PF combustion plants. All samples were run in a nitrogen atmosphere at a heating rate of 10 deg. C/min. In comparison with the standard method, the new methods are objective and have superior repeatability and sensitivity. Furthermore, the two methods enable the melting behavior to be characterized by a continuous measurement of melt fraction versus temperature. Due to this two-dimensional resolution of the results, the STA and HTLM methods provide more information than the standard method. The study of bottom ash and fly ash as well as deposit samples from straw test firings at the Haslev and Slagelse Combined Heat and Power plants resulted in a better understanding of mineral behaviour during straw grate firing. In these tests a number of straws were fired which had been carefully selected for having different qualities with respect to sort and potassium and chlorine contents. By studying bottom ashes from Slagelse it was found that the melting behaviour correlated with the deposition rate on a probe situated at the outlet part of the combustion zone. (EG)

  20. 灰化温度及热解气氛对生物质灰灼烧失重特性的影响%Influence of ashing temperature and pyrolysis atmosphere on weight loss properties of biomass ash obtained by combustion

    Institute of Scientific and Technical Information of China (English)

    姚锡文; 许开立

    2015-01-01

    Nowadays, sustainable development and increasing fuel demand necessitate the identification of possible energy resources. Biomass resource is regarded as a green renewable energy and will be more important in the future, which attracts the worldwide attention regarding their renewable nature, carbon dioxide-neutral characteristic, and world-wide availability. Consequently, many countries are putting great emphasis on the exploration of bio-energy. However, the use of biomass as fuel generates a large amount of residual ash, which causes serious environmental problems and has great passive influence on the chemical conversion of biomass. The biomass ash is easy to melt and volatilize, and it can not only reduce the utilization efficiency of equipment but also shorten their service life. Moreover, the inorganic species existing in biomass such as alkali oxides and salts can aggravate agglomeration, deposition, and corrosion problems on boiler’s heat transfer surfaces. So during the combustion or gasification processing, the ash with complex composition and high volatility often leads to slugging and erosion/corrosion in thermal conversion processing systems. Rice husk (RH) and rice straw (RS) are the main by-products during the process of rice processing, and they are the clean and renewable energy. Especially, in comparison to other agricultural wastes, the ash content of RH is much higher. So far, a series of studies have been carried out to investigate the characteristics of biomass ash through experiment. But the studies on the influence of ashing temperature and pyrolysis atmosphere on the properties of biomass ash are limited. In this paper, in order to investigate the weight loss regularities of biomass ash at different ashing temperature and pyrolysis atmosphere, thermogravimetric analysis was conducted to comparatively study the pyrolysis weight loss mechanism of rice husk ash (RHA) and rice straw ash (RSA) ashing at 600 and 815℃ in air and nitrogen. The

  1. Properties and Leachability of Self-Compacting Concrete Incorporated with Fly Ash and Bottom Ash

    Science.gov (United States)

    Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Jamaluddin, Norwati; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The process of combustion in coal-fired power plant generates ashes, namely fly ash and bottom ash. Besides, coal ash produced from coal combustion contains heavy metals within their compositions. These metals are toxic to the environment as well as to human health. Fortunately, treatment methods are available for these ashes, and the use of fly ash and bottom ash in the concrete mix is one of the few. Therefore, an experimental program was carried out to study the properties and determine the leachability of selfcompacting concrete incorporated with fly ash and bottom ash. For experimental study, self-compacting concrete was produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a replacement for sand with the ratios of 10%, 20%, and 30% respectively. The fresh properties tests conducted were slump flow, t500, sieve segregation and J-ring. Meanwhile for the hardened properties, density, compressive strength and water absorption test were performed. The samples were then crushed to be extracted using Toxicity Characteristic Leaching Procedure and heavy metals content within the samples were identified accordingly using Atomic Absorption Spectrometry. The results demonstrated that both fresh and hardened properties were qualified to categorize as self-compacting concrete. Improvements in compressive strength were observed, and densities for all the samples were identified as a normal weight concrete with ranges between 2000 kg/m3 to 2600 kg/m3. Other than that, it was found that incorporation up to 30% of the ashes was safe as the leached heavy metals concentration did not exceed the regulatory levels, except for arsenic. In conclusion, this study will serve as a reference which suggests that fly ash and bottom ash are widely applicable in concrete technology, and its incorporation in self-compacting concrete constitutes a potential means of adding value to appropriate mix and design.

  2. Ash Deposition Trials at Three Power Stations in Denmark

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming; Larsen, Ole Hede

    1998-01-01

    the probe temperature did influence the composition of deposits for coals with medium ash deposition propensities. These results may indicate that coals with medium to high ash deposition propensities in existing boilers may cause increasing ash deposit formation in future boilers with higher steam...

  3. ExB mean flows in finite ion temperature plasmas

    CERN Document Server

    Madsen, J; Naulin, V; Nielsen, A H

    2016-01-01

    The impact of ion pressure dynamics on E x B mean flows is investigated. Three stresses in addition to the Reynolds stress are shown to modify the E x B mean flow. These additional terms in the stress tensor all require ion pressure fluctuations. Quasi-linear analysis indicates that these additional stresses are as important as the standard Reynolds stress and hence must be taken into account in analysis of E x B mean flows.

  4. Analytical study on coolant temperature of several leak flows in the experimental VHTr core

    International Nuclear Information System (INIS)

    This report describes heat transfer analysis of several leak flows which bypass main coolant flow path in the experimental VHTR core. The analysis contains the leak flow at permanent reflectors, replaceable reflectors and gaps between fuel columns. The summary of the results are as follows: (1) the temperature of the leak flow gas increases up to the surface temperature of permanent reflectors, (2) the gas temperature at replaceable reflectors increases at least 400C in case of the worst analytical condition, (3) the gas temperature increases remarkably with decreasing equivalent diameter which is changed by the angle of bevel edge of the reflector, (4) while the gas temperature is low at the upper part of the fuel element, the temperature increases rapidly when it flow down along the gap of the fuel columns. (author)

  5. Plastic flow peculiarities of V-4Ti-4Cr alloys under high temperatures

    International Nuclear Information System (INIS)

    Full text of publication follows: Mechanical properties and plastic flow peculiarities of V-4Ti-4Cr alloys (Russian technology) in temperature interval 300-1100 K under tension and compression tests (the deformation rate is 10-3 s-1) have been researched. The temperature windows have been determined, inside which the serrated flow and anomaly strengthening of the alloys arises. The serrated flow is observed under tension and compression flows, but the value of the stress drop is lower under compression than under tension. The flow mechanism of alloys changes under the temperature ∼700 K (there is a bend on the temperature dependence of the stress drop). Inside the temperature intervals where there is the serrated flow, the anomaly strengthening of the alloys is observed (the yield point and yield stress increase as the temperature increases). Using the X-ray analysis, the peculiarities of the structure state of the solid solutions for the alloys and metallic vanadium (initial and after plastic flow states under different temperatures) have been researched. The solid solutions (substitutional and interstitial elements) are divided and the heterophase structures of the alloys are observed. The type and the intensity of the concentration layering are controlled by the interstitial elements (the temperature up to 570-620 K ) and the substitutional elements, especially titanium (the temperature 670-970 K). The model of the serrated flow of the alloys has been suggested and the criteria of its realization have been determined. (authors)

  6. Water temperature in irrigation return flow from the Upper Snake Rock watershed

    Science.gov (United States)

    Water returning to a river from an irrigated watershed could increase the water temperature in the river. The objective of this study was to compare the temperature of irrigation return flow water with the temperature of the diverted irrigation water. Water temperature was measured weekly in the mai...

  7. Can vegetative ash be water repellent?

    Science.gov (United States)

    Bodí, M. B.; Cerdà, A.; Mataix-Solera, J.; Doerr, S. H.

    2012-04-01

    In most of the literature, ash is referred to as a highly wettable material (e.g. Cerdà and Doerr, 2008; Etiegni and Campbell, 1991; Woods and Balfour 2010). However, the contrary was suggested in few articles, albeit with no further quantification (Gabet and Sternberg, 2008; Khanna et al., 1996; Stark, 1977). To clarify this question, water repellency measurements on ash using the Water Drop Penetration Times (WDPT) method were performed on ash from Mediterranean ecosystems and it was found to be water repellent (Bodí et al. 2011). Water repellency on ash from different wildfires ranged from 40 to 10 % occurrence with samples being extreme repellent (lasting more than 3600 s to penetrate). Part of the ash produced in the laboratory was also water repellent. After that, other ash samples had been found water repellent in wildfires in Colorado (unpublished results), Portugal (Gonzalez-Pelayo, 2009), or in prescribed fires in Australia (Bodí et al. 2011b; Petter Nyman, personnal communication). All the samples exhibiting water repellent properties had in common that were combusted at low temperatures, yielding in general ash with dark colour and contents of organic carbon of more than 18 % (Bodí et al. 2011a), although these properties were not exactly proportional to its water repellency occurrence or persistence. In addition, the species studied in Bodí et al. (2011) had been found to produce different levels of WR repellency, being ash from Pinus halepensis more repellent than that from Quercus coccifera and Rosmarins officinalis. Ash from Eucaliptus radiata had been found also very water repellent, as Pinus halepensis (unpublished data). The reasons of the existance of water repellent ash are that the charred residue produced by fire (an also contained in the ash) can contain aromatic compounds that have a lower free energy than water and therefore behave as hydrophobic materials with reduced solubility (Almendros et al., 1992 and Knicker, 2007

  8. Volcanic ash: What it is and how it forms

    Energy Technology Data Exchange (ETDEWEB)

    Heiken, G.

    1991-09-13

    There are four basic eruption processes that produce volcanic ash: (1) decompression of rising magma, gas bubble growth, and fragmentation of the foamy magma in the volcanic vent (magmatic), (2) explosive mixing of magma with ground or surface water (hydrovolcanic), (3) fragmentation of country rock during rapid expansion of steam and/or hot water (phreatic), and (4) breakup of lava fragments during rapid transport from the vent. Variations in eruption style and the characteristics of volcanic ashes produced during explosive eruptions depend on many factors, including magmatic temperature, gas content, viscosity and crystal content of the magma before eruption, the ratio of magma to ground or surface water, and physical properties of the rock enclosing the vent. Volcanic ash is composed of rock and mineral fragments, and glass shards, which is less than 2 mm in diameter. Glass shard shapes and sizes depend upon size and shape of gas bubbles present within the magma immediately before eruption and the processes responsible for fragmentation of the magma. Shards range from slightly curved, thin glass plates, which were broken from large, thin-walled spherical bubble walls, to hollow needles broken from pumiceous melts containing gas bubbles stretched by magma flow within the volcanic vent. Pumice fragments make up the coarser-grained portions of the glass fraction. Particle sizes range from meters for large blocks expelled near the volcanic vent to nanometers for fine ash and aerosol droplets within well-dispersed eruption plumes. 18 refs., 6 figs., 1 tab.

  9. Volcanic ash impacts on critical infrastructure

    Science.gov (United States)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water

  10. 78 FR 65306 - Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams

    Science.gov (United States)

    2013-10-31

    ... AGENCY Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams AGENCY...: EPA is announcing a 30-day public comment period for the draft document titled, ``Best Practices for... Development. The report describes best practices for the deployment of continuous temperature and flow...

  11. Ash transformation during co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn;

    2007-01-01

    Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal...... quality on fly ash and deposit properties, straw was co-fired with three kinds of coal in an entrained flow reactor. The compositions of the produced ashes were compared to the available literature data to find suitable scaling parameters that can be used to predict the composition of ash from straw and...... coal co-firing. Reasonable agreement in fly ash compositions regarding total K and fraction of water soluble K was obtained between co-firing in an entrained flow reactor and full-scale plants. Capture of potassium and subsequent release of HCl can be achieved by sulphation with SO2 and more...

  12. Nonlinear vacuum gas flow through a short tube due to pressure and temperature gradients

    International Nuclear Information System (INIS)

    The flow of a rarefied gas through a tube due to both pressure and temperature gradients has been studied numerically. The main objective is to investigate the performance of a mechanical vacuum pump operating at low temperatures in order to increase the pumped mass flow rate. This type of pump is under development at CEA-Grenoble. The flow is modelled by the Shakhov kinetic model equation, which is solved by the discrete velocity method. Results are presented for certain geometry and flow parameters. Since according to the pump design the temperature driven flow is in the opposite direction than the main pressure driven flow, it has been found that for the operating pressure range studied here the net mass flow rate through the pump may be significantly reduced

  13. Resonating microbridge mass flow sensor with low-temperature glass-bonded cap wafer

    OpenAIRE

    Legtenberg, Rob; Bouwstra, Siebe; Fluitman, Jan H.J

    1991-01-01

    A resonating microbridge mass flow sensor has been realized suspended inside a micro flow channel. Thin-film technologies and micromachining are used for the fabrication of the sensor wafer and a cap wafer with opposing V-grooves. A low-temperature glass-bonding technique is used to assemble the wafers allowing for feedthrough of the electrical connections. Measurements show sensitivities of the resonance frequency of several kHz per sccm nitrogen gas flows at average temperature elevations o...

  14. Optimization of CLSM mix proportion with combination of clinker ash and fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Horiguchi, T.; Okumura, H.; Saeki, N. [Hokkaido Univ., Sapporo (Japan)

    2001-07-01

    The disposal of clinker ash and fly ash in Japan is becoming an ecological problem which is being addressed by several research institutions in the country. This study evaluated the effective application of a wide range of off-specification fly ash plus non standard clinker ash in CLSM. CLSM is defined by the ACI Cement and Concrete Terminology as material that results in a compressive strength of 8275 kPa or less at the age of 28 days. In particular, this study examined the effect of mixture proportions on the short-term and long-term compressive strength of CLSM. The cement used in this study was portland cement whose physical and chemical properties were determined by the Japan Industrial Standard. Two different types of fly ash and three different types of clinker ash in different compositions were used. The major differences were in the specific gravity and water absorption capabilities. The various slurry mixtures were tested for flowability, bleeding, segregation and compressive strength and the test results were summarized. It was determined that slump flow varied from 140 to 200 mm. The mixtures satisfied the target value to ensure adequate flowability. Bleeding ratio varied from 1.5 to 6.7 per cent, which is significantly higher than that of ordinary flowable fills. Also, the density of CLSM varied from 1338 to 2056 kg per cubic metre, which is also much lighter than cement mortar, a significant advantage. This paper described the effect of fly ash quality on the compressive strength, the optimum clinker ash composition, and the strength development estimation. It was concluded that there is no significant disadvantage in using fly ash or clinker ash in CLSM. In fact, clinker ash reduces bleeding of CLSM. The optimum proportion of clinker substitution was found to be 50 per cent. The strength of CLSM with fly ash and clinker ash was found to increase significantly up to 91 days. 15 refs., 5 tabs., 9 figs.

  15. Evaluation of ash deposits during experimental investigation of co-firing of Bosnian coal with wooden biomass

    Energy Technology Data Exchange (ETDEWEB)

    Smajevic, Izet; Kazagic, Anes [JP Elektroprivreda BiH d.d., Sarajevo (Bosnia and Herzegovina); Sarajevo Univ. (Bosnia and Herzegovina). Faculty of Mechanical Engineering

    2008-07-01

    The paper is addressed to the development and use different criteria for evaluation of ash deposits collected during experimental co-firing of Bosnian coals with wooden biomass. Spruce saw dust was used for the co-firing tests with the Kakanj brown coal and with a lignite blend consisted of the Dubrave lignite and the Sikulje lignite. The coal/biomass mixtures at 93:7 %w and at 80:20 %w were tested. Experimental lab-scale facility PF entrained flow reactor is used for the co-firing tests. The reactor allows examination of fouling/slagging behaviors and emissions at various and infinitely variable process temperature which can be set at will in the range from ambient to 1560 C. Ash deposits are collected on two non-cooled ceramic probes and one water-cooled metal surface. Six different criteria are developed and used to evaluate behavior of the ash deposits on the probes: ash deposit shape, state and structure, which are analyzed visually - photographically and optically by a microscope, rate of adhesion and ash deposit strength, analyzed by physic acting to the ash deposits, and finally deposition rate, determined as a mass of the deposit divided by the collecting area and the time of collecting. Furthermore, chemical composition analysis and AFT of the ash deposits were also done to provide additional information on the deposits. (orig.)

  16. Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer

    Science.gov (United States)

    Hilado, C. J.; Brick, V. E.; Brauer, D. P.

    1978-01-01

    A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.

  17. Assessment of Ash Pond Project effectiveness

    International Nuclear Information System (INIS)

    In April 1989 the US Department of Energy (DOE) completed the Ash Pond Isolation Project at the Weldon Spring Site Remedial Action Project (WSSRAP). This Interim Response Action (IRA) was designed to reduce uranium concentrations in surface water released from the Ash Pond Outfall at the Weldon Spring Site (WSS). Uranium concentrations at this outfall have been measured as high as 5,500 pCi/l with an average concentration of 1,498 pCi/l. This project was one of several IRAs aimed at improving health and safety conditions at the WSS prior to the Record of Decision. The Ash Pond Isolation Project was constructed to intercept surface water runoff to the Ash Pond drainage and redirect flows around the Ash Pond and South Dump areas, thereby eliminating leaching and transport of uranium-contaminated materials from these source areas. The DOE has monitored the releases from the Ash Pond Outfall in fulfillment of the site's National Pollutant Discharge Elimination System Permit and initiated additional monitoring to further assess the effectiveness of the Ash Pond Isolation Project. Results of this monitoring effort indicate a reduction in uranium concentrations measured at the Ash Pond Outfall from a pre-completion average of 1,498 pCi/l to an average of 145 pCi/l following completion of the IRA. 6 refs., 6 figs., 3 tabs

  18. Enhancement of reactivity in Li4SiO4-based sorbents from the nano-sized rice husk ash for high-temperature CO2 capture

    International Nuclear Information System (INIS)

    Highlights: • The Li4SiO4 sorbent from nano-sized rice husk ash was prepared and characterized. • The Aerosil and Quartz were comparably used for synthesized Li4SiO4. • The structure of sorbent was depended on the morphology of heated silicon materials. • The pretreatment sorbent showed increase in the CO2 uptake and kinetic behavior. • This promising sorbent also maintained higher capacities during the multiple cycles. - Abstract: Using the cost-effective, renewable and nano-sized of citric acid pretreatment rice husk ash (CRHA) as silicon source, high efficient Li4SiO4 (lithium orthosilicate)-based sorbents (CRHA-Li4SiO4) for high-temperature CO2 capture were prepared through the solid-state reaction at lower temperature (700 °C). Two typical raw materials (nano-structured Aerosil and crystalline Quartz powders) were used to synthesize Li4SiO4 sorbents (Aerosil-Li4SiO4 and Quartz-Li4SiO4) for comparison purposes. The phase composition behavior, surface area, and morphology of the silicon sources, heat treated raw materials and as-received Li4SiO4 sorbents were studied by analytical techniques. The CO2 adsorption capacity and adsorption–desorption performance were tested by the thermo-gravimetric analyses (CO2 atmosphere) and a fixed bed reactor, respectively. Compared with the case of its original samples, the morphology of heat treated raw materials had a greater effect on the phase composition, microstructure, special surface area and CO2 adsorption properties of their resulting sorbents. Although the calcined Quartz sample maintained the structure of micron particles, its reactivity was not enough to react completely with Li2CO3. Due to the greater reactivity of nanoparticles, Aerosil-Li4SiO4 presented pure of Li4SiO4 whereas it obtained large particles with dense morphology, which was coming from the pronounced fusing of silica nanoparticles during the calcined process. Conversely, CRHA-Li4SiO4 achieved porous agglomerates of submicron particles

  19. Vitrification of simulated radioactive Rocky Flats plutonium containing ash residue with a Stir Melter System

    International Nuclear Information System (INIS)

    A demonstration trial has been completed in which a simulated Rocky Flats ash consisting of an industrial fly-ash material doped with cerium oxide was vitrified in an alloy tank Stir-Melter trademark System. The cerium oxide served as a substitute for plutonium oxide present in the actual Rocky Flats residue stream. The glass developed falls within the SiO2 + Al2O3/ΣAlkali/B2O3 system. The glass batch contained approximately 40 wt% of ash, the ash was modified to contain ∼ 5 wt% CeO2 to simulate plutonium chemistry in the glass. The ash simulant was mixed with water and fed to the Stir-Melter as a slurry with a 60 wt% water to 40 wt% solids ratio. Glass melting temperature was maintained at approximately 1,050 C during the melting trials. Melting rates as functions of impeller speed and slurry feed rate were determined. An optimal melting rate was established through a series of evolutionary variations of the control variables' settings. The optimal melting rate condition was used for a continuous six hour steady state run of the vitrification system. Glass mass flow rates of the melter were measured and correlated with the slurry feed mass flow. Melter off-gas was sampled for particulate and volatile species over a period of four hours during the steady state run. Glass composition and durability studies were run on samples collected during the steady state run

  20. Vitrification of simulated radioactive Rocky Flats plutonium containing waste ash with a stir-melter system

    International Nuclear Information System (INIS)

    A demonstration trial has been completed in which a simulated Rocky Flats ash consisting of an industrial fly-ash material doped with cerium oxide was vitrified in an alloy tank Stir-Melter trademark System. The cerium oxide served as a substitute for plutonium oxide present in the actual Rocky Flats waste stream. The glass developed falls within the SiO2 +Al2O3 / ΣAlkali / B2O3 System. The glass batch contained approximately 40 wt % of ash, the ash was modified to contain ∼5 wt % CeO2 to simulate plutonium chemistry in the glass. The ash simulant was mixed with water and fed to the Stir-Melter as a slurry with a 60 wt % water to 40 wt % solids ratio. Glass melting temperature was maintained at approximately 1050 degrees C during the melting trials. Melting rates as functions of impeller speed and slurry feed rate were determined. An optimal melting rate was established through a series of evolutionary variations of the control variables' settings. The optimal melting rate condition was used for a continuous six hour steady state run of the vitrification system. Glass mass flow rates out of the melter were measured and correlated with the slurry feed mass flow. Melter off-gas was sampled for particulate and volatile species over a period of four hours during the steady state run. Glass composition and durability studies were run on samples collected during the steady state run

  1. An experimental investigation of fluid flow and wall temperature distributions in an automotive headlight

    International Nuclear Information System (INIS)

    Detailed measurements of wall temperatures and fluid flow velocities inside an automotive headlight with venting apertures are presented. Thermocouples have been used to characterize the temperature distributions in the walls of the reflectors under transient and steady operating conditions. Quantification of the markedly three-dimensional flow field inside the headlight cavities was achieved through the use of laser-Doppler velocimetry for the latter condition only. Significant thermal stratification occurs in the headlight cavities. The regime corresponding to steady operating conditions is characterized by the development of a vortex-dominated flow. The interaction of the main vortex flow with the stream of colder fluid entering the enclosed volume through the venting aperture contributes significantly to increase the complexity of the basic flow pattern. Globally, the results have improved the understanding of the temperature loads and fluid flow phenomena inside a modern automotive headlight

  2. Characterisation of Turkish fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, O. [Cukurova University, Adana (Turkey). Mining Engineering Dept.

    1998-07-01

    The mineralogical, morphological, physical and chemical properties of 7 fly ashes from coal fields in Turkey are compared. The mineral matter in the fly ashes, determined by X-ray diffraction, is dominated by anhydride, lime, quartz and hematite + ferrite spinel. The three low-calcium ashes have the typical, relatively simple, crystalline phase Q, M, H and FS. The high-calcium fly ashes have the most complex assemblage of crystalline phases. The much higher calcium concentrations in these samples result in the formation of lime (CaO), melilite ((Ca, Na){sub 2}(Mg,Al,Fe)(Si,Al){sub 2}O{sub 7}) and merwinite. The presence of anhydride in all samples indicates that the high activity of calcium not only promotes the formation of sulfates from calcite but also the dehydration of gypsum during and after combustion, which occurs at temperatures above 400-500{degree}C. It is important to understand the interaction of high-calcium fly ashes with water occurring in Portland cement (C{sub 3}A,C{sub 2}S), Ah, which hydrates to give gypsum and lime, with the latter hydrating to give the Ca(OH){sub 2} solutions that promote pozzolonic reactions. Some of the particles comprised irregularly formed, vesicular particles with some well-formed individual spheres in Catalagzi and Tuncbilek fly ashes. About 55-80 wt% was less than 45 {mu}m in size for Yatagan, Soma, Yenikoy and Afsin-Elbistan fly ashes. The fly ashes were mainly composed of CaO, SiO{sub 2} and Al{sub 2}O{sub 3}. They have a potential use in wastewater treatment since they can be easily obtained in large quantities at low price or even free. The chemical and mineralogical compositions of the high-calcium Turkish fly ashes investigated make them a good binding agent and a possible substitute for slags, pozzolana and gypsum in the amelioration of clinker. 53 refs., 10 figs., 5 tabs.

  3. Natural-Scale Lava Flow Experiments on Video: Variations with Temperature, Slope, and Effusion Rate

    Science.gov (United States)

    Karson, J. A.; Wysocki, R.; Edwards, B. R.; Lev, E.

    2013-12-01

    Investigations of active basaltic lava flows and analog materials show that flow dynamics and final flow morphology are strongly determined by the rapidly evolving rheology of the lava crust which constrains the downslope advance of the lava flow. The non-dimensional factor Ψ (ratio of the time scale of crust formation to advective heat loss) provides a useful means of comparing different flows. The key parameters that control Ψ include the melt viscosity, temperature, effusion rate, and slope. Experimental lava flows, up to several meters long created in the Syracuse University Lava Project permit these variables to be investigated independently and in combination in volume-limited flows (inflated lobes, break-outs, and bubbles (limu o'Pele), that provide additional information on lava crust development. New, continuous flow (cooling-limited) experiments show downslope variations under constant flow conditions.

  4. Effect of Acupuncture Manipulations at LI4 or LI11 on Blood Flow and Skin Temperature.

    Science.gov (United States)

    Li, Weihui; Ahn, Andrew

    2016-06-01

    Acupuncture induces physiological changes, and patients have reported warm or cool sensations with "Burning Fire" (BF) or "Penetrating Cool" (PC) manipulations. This study aimed to evaluate whether these techniques had distinct effects on skin temperature and blood flow and to examine whether skin temperature correlated with blood flow. The participants were 25 healthy volunteers, each receiving acupuncture manipulations on points LI4 and LI11 bilaterally. Skin temperatures and blood flow were recorded continuously on both arms. The study found that acupuncture significantly increased skin temperature on the needling arm by 0.3514°C on average, but decreased it on the contralateral arm by 0.2201°C on average. Blood flow decreased significantly in both arms during needling (-3.4% and -5.97% for the ipsilateral and the contralateral sides, respectively), but the changes in skin temperature did not correlate with the changes in blood flow. Furthermore, these changes were not significantly different between acupuncture techniques and acupuncture points. In conclusion, acupuncture changes local skin temperature and blood flow independent of the manipulation technique. Moreover, blood flow may not be affected by the increased temperature on the needling arm. These results help to verify traditional Chinese medicine concepts and may help in establishing standards for acupuncture treatments. PMID:27342886

  5. Heat flow and temperature-depth curves throughout Alaska: finding regions for future geothermal exploration

    Science.gov (United States)

    Batir, Joseph F.; Blackwell, David D.; Richards, Maria C.

    2016-06-01

    The objective of this research is to contribute to the understanding of the thermal regime of Alaska and its relationship to geology, regional tectonics, and to suggest potential sites for future geothermal energy production. New heat flow data were collected and are combined with existing published and unpublished data, although large sections of Alaska still lack data. Fault traces were implemented into the heat flow contouring as an additional gridding constraint, to incorporate both heat flow measurements and geology. New heat flow data supported the use of geologic trends in the heat flow mapping procedure, and a heat flow map of Alaska was produced with this added constraint. The multi-input contouring strategy allows production of a map with a regional interpretation of heat flow, in addition to site-specific heat flow and thermal model interpretations in areas with sufficient data density. Utilizing the new heat flow map, temperature-at-depth curves were created for example areas. Temperature-at-depth curves are calculated to 10 km depth for the areas of Anchorage, Fairbanks, Juneau, the Alaska Peninsula, Bristol Bay, and the Copper River Basin. The temperatures-at-depth predicted near the population centers of Anchorage and Juneau are relatively low, limiting the geothermal resource potential. The Fairbanks area temperature estimates are near conventional power production temperatures (150 °C) between 3.5 and 4 km. All data areas, except at Juneau, have temperatures sufficient for low temperature geothermal applications (40 °C) by 2 km. A high heat flow region exists within the Aleutian Volcanic Arc, although new data show heat flow variations from 59 to 120 mW m‑2, so individual geothermal resources within the arc will be irregularly located.

  6. Speciation of Chromium in Bottom Ash Obtained by the Incineration of the Leather Waste Shavings

    Directory of Open Access Journals (Sweden)

    k. louhab

    2006-01-01

    Full Text Available The evolution of bottom ash morphology and chromium metals behavior during incineration of a leather waste shavings at different incineration temperature have been studied. The Cr, Ca, Mg, Cl rates in bottom ashes, flay ashes and emitted gases in different incineration temperature of the tannery wastes are also determined. The morphology of the bottom ashes obtained by incineration at different temperature from the leather waste shavings was examined by MEB. The result show that the temperature and the length of incineration influence on the structure of the bottom ash and on the chromium in the bottom ash.

  7. A Novel Microfluidic Flow Rate Detection Method Based on Surface Plasmon Resonance Temperature Imaging.

    Science.gov (United States)

    Deng, Shijie; Wang, Peng; Liu, Shengnan; Zhao, Tianze; Xu, Shanzhi; Guo, Mingjiang; Yu, Xinglong

    2016-01-01

    A novel microfluidic flow rate detection method based on surface plasmon resonance (SPR) temperature imaging is proposed. The measurement is performed by space-resolved SPR imaging of the flow induced temperature variations. Theoretical simulations and analysis were performed to demonstrate a proof of concept using this approach. Experiments were implemented and results showed that water flow rates within a wide range of tens to hundreds of μL/min could be detected. The flow rate sensor is resistant to disturbances and can be easily integrated into microfluidic lab-on-chip systems. PMID:27347960

  8. Quantification of fusion in ashes from solid fuel combustion

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug; Frandsen, Flemming; Dam-Johansen, Kim;

    1999-01-01

    which the agreement with fusion as determined by phase diagrams is very good, and for straw (salt-rich) and coal (silicate-rich) ashes. Comparing ash fusion curves to index points of current standard ash fusion tests showed initial melting at temperatures typically between 50 degrees and 100 degrees C......The fusion of ashes produced during solid fuel combustion greatly affects the tendency of these ashes to cause operational problems in utility boilers. In this paper, a new and quantitative laboratory method for assessing the fusion of ashes based on simultaneous thermal analysis, STA, is described....... Using STA, melting is detected as an endothermic reaction involving no change in mass. The measurement signals are transferred into a fusion curve showing the melt fraction in the ash as a function of temperature. This is done either by a simple comparison of the energies used for melting in different...

  9. Reburning Characteristics of Residual Carbon in Fly Ash from CFB Boilers

    Science.gov (United States)

    Zhang, S. H.; Luo, H. H.; Chen, H. P.; Yang, H. P.; Wang, X. H.

    The content of residual carbon in fly ash of CFB boilers is a litter high especially when low-grade coal, such as lean coal, anthracite coal, gangue, etc. is in service, which greatly influences the efficiency of boilers and fly ash further disposal. Reburn of fly ash through collection, recirculation in CFB furnace or external combustor is a possibly effective strategy to decrease the carbon content, mainly depending on the residual carbon reactivity. In this work, the combustion properties of residual carbon in fly ash and corresponding original coal from large commercial CFB boilers (Kaifeng (440t/h), and Fenyi (410t/h), all in china) are comparably investigated through experiments. The residual carbon involved was firstly extracted and enriched from fly ash by means of floating elutriation to mitigate the influence of ash and minerals on the combustion behavior of residual carbon. Then, the combustion characteristic of two residual carbons and the original coal particles was analyzed with thermogravimetric analyzer (TGA, STA409C from Nestch, Germany). It was observed that the ignition temperature of the residual carbon is much higher than that of original coal sample, and the combustion reactivity of residual carbon is not only dependent on the original coal property, but also the operating conditions. The influence of oxygen content and heating rate was also studied in TGA. The O2 concentration is set as 20%, 30%, 40% and 70% respectively in O2/N2 gas mixture with the flow rate of 100ml/min. It was found that higher oxygen content is favor for decreasing ignition temperature, accelerating the combustion rate of residual carbon. And about 40% of oxygen concentration is experimentally suggested as an optimal value when oxygen-enriched combustion is put into practice for decreasing residual carbon content of fly ash in CFB boilers.

  10. Chemical reactions accompanying fluid flow through granite held in a temperature gradient

    Science.gov (United States)

    Moore, Diane E.; Morrow, C.A.; Byerlee, J.D.

    1983-01-01

    Distilled water was passed at a low rate down a temperature gradient through cylinders of Barre and Westerly Granite. Temperatures ranged from 80-100??C at the outer edges of the cylinders to 250-300??C in central, drilled holes which housed the heating coils. The measured permeabilities of the granite cylinders decreased by as much as two orders of magnitude in experiments of 1-3 weeks' duration. The amount of permeability decrease varied directly with temperature and inversely with the rate of fluid flow. The compositions of the fluids discharged from the granites were functions of temperature and flow rate as well as mineral composition, with dissolved silica concentrations showing trends different from those of the other analyzed species. Fluids from experiments run at higher temperatures but at much lower initial rates of fluid flow had higher concentrations of most ions but substantially lower dissolved silica contents. In contrast, an increase in temperature at similar rates of fluid flow resulted in higher silica concentrations. In the experiments, the distilled water acquired enough dissolved materials at high temperatures to become supersaturated with respect to several minerals at the low-temperature edges of the cylinders. Some of this material, particularly silica, was deposited along grain boundaries and microfractures, causing the observed permeability decreases. The very low rates of fluid flow in some high-temperature experiments significantly increased the rates of SiO2 precipitation and reduced dissolved silica concentrations relative to other species in the discharged fluids. ?? 1983.

  11. The effects of water flow and temperature on thermal regime around a culvert built on permafrost

    Institute of Scientific and Technical Information of China (English)

    Loriane Prier; Guy Dor; CR Burn

    2014-01-01

    Temperature and water flow through a culvert beneath the Alaska Highway near Beaver Creek, Yukon, were measured at hourly intervals between June and October 2013. These data were used to simulate the effect of the culvert on the thermal regime of the road embankment and subjacent permafrost. A 2-D thermal model of the embankment and permafrost was developed with TEMP/W and calibrated using field observations. Empirical relations were obtained between water tem-peratures at the entrance to the culvert, flow into the culvert, and water temperatures inside the structure. Water temper-atures at the entrance and inside the culvert had a linear relation, while water temperatures inside the culvert and water flow were associated by a logarithmic relation. A multiple linear regression was used to summarize these relations. From this relationship, changes in the flow rate and water temperatures at the entrance of the culvert were simulated to obtain pre-dicted water temperatures in the culvert. The temperatures in the culvert were used in the thermal model to determine their effects on the ground thermal regime near the culvert. Variation of ±10%in water flow rate had no impact on the thermal regime underneath the culvert. Variation of water temperature at the entrance of the culvert had a noticeable influence on the thermal regime. A final simulation was conducted without insulation beneath the culvert. The thaw depth was 30 cm with insulation, and 120 cm without insulation, illustrating the importance of insulation to the ground thermal regime.

  12. Interstellar Flow and Temperature Determination with IBEX: Robustness and Sensitivity to Systematic Effects

    Science.gov (United States)

    Möbius, E.; Bzowski, M.; Frisch, P. C.; Fuselier, S. A.; Heirtzler, D.; Kubiak, M. A.; Kucharek, H.; Lee, M. A.; Leonard, T.; McComas, D. J.; Schwadron, N. A.; Sokół, J. M.; Swaczyna, P.; Wurz, P.

    2015-10-01

    The Interstellar Boundary Explorer (IBEX) samples the interstellar neutral (ISN) gas flow of several species every year from December through late March when the Earth moves into the incoming flow. The first quantitative analyses of these data resulted in a narrow tube in four-dimensional interstellar parameter space, which couples speed, flow latitude, flow longitude, and temperature, and center values with approximately 3° larger longitude and 3 km s-1 lower speed, but with temperatures similar to those obtained from observations by the Ulysses spacecraft. IBEX has now recorded six years of ISN flow observations, providing a large database over increasing solar activity and using varying viewing strategies. In this paper, we evaluate systematic effects that are important for the ISN flow vector and temperature determination. We find that all models in use return ISN parameters well within the observational uncertainties and that the derived ISN flow direction is resilient against uncertainties in the ionization rate. We establish observationally an effective IBEX-Lo pointing uncertainty of ±0.°18 in spin angle and confirm an uncertainty of ±0.°1 in longitude. We also show that the IBEX viewing strategy with different spin-axis orientations minimizes the impact of several systematic uncertainties, and thus improves the robustness of the measurement. The Helium Warm Breeze has likely contributed substantially to the somewhat different center values of the ISN flow vector. By separating the flow vector and temperature determination, we can mitigate these effects on the analysis, which returns an ISN flow vector very close to the Ulysses results, but with a substantially higher temperature. Due to coupling with the ISN flow speed along the ISN parameter tube, we provide the temperature {T}{VISN∞ }=8710+440/-680 K for {V}{ISN∞ }=26 {km} {{{s}}}-1 for comparison, where most of the uncertainty is systematic and likely due to the presence of the Warm Breeze.

  13. Experimental evaluation of permanent magnet probe flowmeter measuring high temperature liquid sodium flow in the ITSL

    International Nuclear Information System (INIS)

    Highlights: • An Instrument Test Sodium Loop (ITSL) has been built and tested in various conditions at KAERI. • Free fall of liquid sodium was conducted experimentally and numerically. • A Permanent Magnet Probe Flowmeter (PMPF) was experimented in the ITSL. • Excellent linearity of the PMPF was achieved under high temperature condition. - Abstract: The Instrument Test Sodium Loop (ITSL) installed at Korea Atomic Energy Research Institute (KAERI) is a medium-size experimental facility dedicated to obtaining relevant experimental data of liquid sodium flow characteristics under various thermal hydraulic conditions and sodium purification. The ITSL has been utilized to perform thermal flow measurement of the liquid sodium and to calibrate a Permanent Magnet Probe Flowmeter (PMPF). The primary objective of this study is to obtain liquid sodium flow rate given a wide temperature range using the PMPF. Non-stationary method was adopted for the calibration of the probe given the liquid sodium temperature range of 150–415 °C. A relationship between the measured voltage signal and flow rate was obtained successfully. It is observed that the calibration experiments result in excellent linear relationships between measured voltage and volumetric flow rate at various temperature conditions. Also a computational analysis using FlowMaster, is employed to facilitate the calibration process by predicting the liquid sodium flow rate. Finally the effect of the fluid temperature on thermal flow measurements is discussed in light of the obtained experimental data

  14. Experimental evaluation of permanent magnet probe flowmeter measuring high temperature liquid sodium flow in the ITSL

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Uiju; Kim, Yun Ho [Nuclear engineering Department, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Jong-Man; Kim, Tae-Joon [Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Sung Joong, E-mail: sungjkim@mit.edu [Nuclear engineering Department, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2013-12-15

    Highlights: • An Instrument Test Sodium Loop (ITSL) has been built and tested in various conditions at KAERI. • Free fall of liquid sodium was conducted experimentally and numerically. • A Permanent Magnet Probe Flowmeter (PMPF) was experimented in the ITSL. • Excellent linearity of the PMPF was achieved under high temperature condition. - Abstract: The Instrument Test Sodium Loop (ITSL) installed at Korea Atomic Energy Research Institute (KAERI) is a medium-size experimental facility dedicated to obtaining relevant experimental data of liquid sodium flow characteristics under various thermal hydraulic conditions and sodium purification. The ITSL has been utilized to perform thermal flow measurement of the liquid sodium and to calibrate a Permanent Magnet Probe Flowmeter (PMPF). The primary objective of this study is to obtain liquid sodium flow rate given a wide temperature range using the PMPF. Non-stationary method was adopted for the calibration of the probe given the liquid sodium temperature range of 150–415 °C. A relationship between the measured voltage signal and flow rate was obtained successfully. It is observed that the calibration experiments result in excellent linear relationships between measured voltage and volumetric flow rate at various temperature conditions. Also a computational analysis using FlowMaster, is employed to facilitate the calibration process by predicting the liquid sodium flow rate. Finally the effect of the fluid temperature on thermal flow measurements is discussed in light of the obtained experimental data.

  15. Modelling near subsurface temperature with mixed type boundary condition for transient air temperature and vertical groundwater flow

    Indian Academy of Sciences (India)

    Rajeev Ranjan Kumar; D V Ramana; R N Singh

    2012-10-01

    Near-subsurface temperatures have signatures of climate change. Thermal models of subsurface have been constructed by prescribing time dependent Dirichlet type boundary condition wherein the temperature at the soil surface is prescribed and depth distribution of temperature is obtained. In this formulation it is not possible to include the relationship between air temperatures and the temperature of soil surface. However, if one uses a Robin type boundary condition, a transfer coefficient relates the air and soil surface temperatures which helps to determine both the temperature at the surface and at depth given near surface air temperatures. This coefficient is a function of meteorological conditions and is readily available. We have developed such a thermal model of near subsurface region which includes both heat conduction and advection due to groundwater flows and have presented numerical results for changes in the temperature–depth profiles for different values of transfer coefficient and groundwater flux. There are significant changes in temperature and depth profiles due to changes in the transfer coefficient and groundwater flux. The analytical model will find applications in the interpretation of the borehole geothermal data to extract both climate and groundwater flow signals.

  16. Application of a vortex shedding flowmeter to the wide range measurement of high temperature gas flow

    International Nuclear Information System (INIS)

    A single flowmeter was required for helium gas measurement in a Gas Cooled Fast Breeder Reactor loss of coolant simulator. Volumetric flow accuracy of +-1.0% of reading was required over the Reynolds Number range 6 x 103 to 1 x 106 at flowing pressures from 0.2 to 9 MPa (29 to 1305 psia) at 3500C (6600F) flowing temperature. Because of its inherent accuracy and rangeability, a vortex shedding flowmeter was selected and specially modified to provide for a remoted thermal sensor. Experiments were conducted to determine the relationship between signal attenuation and sensor remoting geometry, as well as the relationship between gas flow parameters and remoted thermal sensor signal for both compressed air and helium gas. Based upon the results of these experiments, the sensor remoting geometry was optimized for this application. The resultant volumetric flow rangeability was 155:1. The associated temperature increase at the sensor position was 90C above ambient (250F) at a flowing temperature of 3500C. The volumetric flow accuracy was measured over the entire 155:1 flow range at parametric values of flowing density. A volumetric flow accuracy of +- % of reading was demonstrated

  17. Application of a vortex shedding flowmeter to the wide range measurement of high temperature gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Baker, S.P.; Ennis, R.M. Jr.; Herndon, P.G.

    1981-01-01

    A single flowmeter was required for helium gas measurement in a Gas Cooled Fast Breeder Reactor loss of coolant simulator. Volumetric flow accuracy of +-1.0% of reading was required over the Reynolds Number range 6 x 10/sup 3/ to 1 x 10/sup 6/ at flowing pressures from 0.2 to 9 MPa (29 to 1305 psia) at 350/sup 0/C (660/sup 0/F) flowing temperature. Because of its inherent accuracy and rangeability, a vortex shedding flowmeter was selected and specially modified to provide for a remoted thermal sensor. Experiments were conducted to determine the relationship between signal attenuation and sensor remoting geometry, as well as the relationship between gas flow parameters and remoted thermal sensor signal for both compressed air and helium gas. Based upon the results of these experiments, the sensor remoting geometry was optimized for this application. The resultant volumetric flow rangeability was 155:1. The associated temperature increase at the sensor position was 9/sup 0/C above ambient (25/sup 0/F) at a flowing temperature of 350/sup 0/C. The volumetric flow accuracy was measured over the entire 155:1 flow range at parametric values of flowing density. A volumetric flow accuracy of +- % of reading was demonstrated.

  18. Experimental study of temperature fluctuations in forced stably stratified turbulent flows

    OpenAIRE

    Eidelman, A.; Elperin, T.; Gluzman, I.; Kleeorin, N.; Rogachevskii, I.

    2012-01-01

    We study experimentally temperature fluctuations in stably stratified forced turbulence in air flow. In the experiments with an imposed vertical temperature gradient, the turbulence is produced by two oscillating grids located nearby the side walls of the chamber. Particle Image Velocimetry is used to determine the turbulent and mean velocity fields, and a specially designed temperature probe with sensitive thermocouples is employed to measure the temperature field. We found that the ratio $\\...

  19. Experimental study of temperature fluctuations in forced stably stratified turbulent flows

    CERN Document Server

    Eidelman, A; Gluzman, Y; Kleeorin, N; Rogachevskii, I

    2013-01-01

    We study experimentally temperature fluctuations in stably stratified forced turbulence in air flow. In the experiments with an imposed vertical temperature gradient, the turbulence is produced by two oscillating grids located nearby the side walls of the chamber. Particle Image Velocimetry is used to determine the turbulent and mean velocity fields, and a specially designed temperature probe with sensitive thermocouples is employed to measure the temperature field. We found that the ratio [(\\ell_x \

  20. Plasma Flow and Temperature in a Gliding Reactor with Different Electrode Configurations

    Directory of Open Access Journals (Sweden)

    J. Sláma

    2012-01-01

    Full Text Available This paper deals with the plasma flow shape depending on the electrode form of a gliding discharge plasma-chemical reactor, and with the temperature distribution along the direction of the plasma flow in one specific electrode form. The shape of the electrodes and their mutual position has a significant influence on the design of a gliding discharge reactor and its applications. It is crucial to know the temperature distribution in the reactor’s chamber design and discharge application. Three configurations with model shapes of wire electrodes were therefore tested (low-divergent, circular, high-divergent and the plasma flow was described. The experiments were performed in air at atmospheric pressure and at room temperature. In order to map the reactive plasma region of the flow we investigated the visible spectral lines that were emitted. The gas temperature was measured using an infrared camera.

  1. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    Science.gov (United States)

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  2. Effect Of Steel Flow Control Devices On Flow And Temperature Field In The Tundish Of Continuous Casting Machine

    Directory of Open Access Journals (Sweden)

    Sowa L.

    2015-06-01

    Full Text Available The mathematical model and numerical simulations of the liquid steel flow in a tundish are presented in this paper. The problem was treated as a complex and solved by the finite element method. One takes into consideration in the mathematical model the changes of thermophysical parameters depending on the temperature. The single-strand tundish is used to casting slabs. The internal work space of the tundish was modified by flow control devices. The first device was a pour pad situated in the pouring tundish zone. The second device was a dam. The third device was a baffle with three holes. The dam and baffle were placed in the tundish at different positions depending on the variant. The main purpose of using these was to put barriers in the steel flow path as well as give directional metal flow upwards which facilitated inclusion floatation. The interaction of flow control devices on hydrodynamic conditions was received from numerical simulations. As a result of the computations carried out, the liquid steel flow and steel temperature fields were obtained. The influences of the tundish modifications on the velocity fields in liquid phase of the steel were estimated, because these have essential an influence on high-quality of a continuous steel cast slab.

  3. Numerical Simulation of Coupled Molten Steel Flow and Temperature Fields in Compact Strip Production Casting

    Institute of Scientific and Technical Information of China (English)

    LIU Xu-feng; ZHANG Jie-yu; DU Wei-dong; ZHAI Qi-jie; LI Qiang

    2007-01-01

    Based on the casting manufacture practice of steel slabs by CSP technology, the flow and the temperature fields of the funnel mould and the secondary cooling segment were simulated using the commercial code,CFX4. Compared with other physical investigations, the correlative data of the present simulation results are in good agreement with them. Therefore, a more comprehensive survey for metallurgy characteristic of the flow and the temperature fields in CSP continuous casting process can be achieved.

  4. Two Models of DMFC under Effects of Cathode Humidification Temperature and Anode Flow Rate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper introduced a novel self-adjustment of parameters of fuzzy neural networks. Then,the effects of cathode humidification temperature and anode flow rate on the performance of direct methanol fuel cell (DMFC)were described respectively. Two dynamic performance models of DMFC under the influences of cathode humidification temperature and anode flow rate were established separately based on fuzzy neural networks. The simulation results show the accuracy of the models established is satisfactory.

  5. The effects of temperature and flow on the migration of salmon and trout in rivers

    International Nuclear Information System (INIS)

    The migration of salmon and trout in rivers is sensitive to changes in water temperature and flow irrespective of whether the migration is into or out of the river. Hydropower development and climate changes, as have been observed in recent years, lead to changes in temperature and flow. Based on investigations of the conditions in the Norwegian river Imsa it is possible to model the influence of changes in these parameters on the migration of these species

  6. Plasma Flow and Temperature in a Gliding Reactor with Different Electrode Configurations

    OpenAIRE

    Sláma, J.

    2012-01-01

    This paper deals with the plasma flow shape depending on the electrode form of a gliding discharge plasma-chemical reactor, and with the temperature distribution along the direction of the plasma flow in one specific electrode form. The shape of the electrodes and their mutual position has a significant influence on the design of a gliding discharge reactor and its applications. It is crucial to know the temperature distribution in the reactor’s chamber design and discharge application. Three...

  7. Influence of temperature and lithium purity on corrosion of ferrous alloys in a flowing lithium environment

    International Nuclear Information System (INIS)

    Corrosion data have been obtained on ferritic HT-9 and Fe-9Cr-1Mo steel and austenitic Type 316 stainless steel in a flowing lithium environment at temperatures between 372 and 5380C. The corrosion behavior is evaluated by measurements of weight loss as a function of time and temperature. A metallograhic characterization of materials exposed to a flowing lithium environment is presented. (orig.)

  8. Intermittent Switching between Potential Flow and Turbulence in Superfluid Helium at mK Temperatures

    OpenAIRE

    Niemetz, Michael; Kerscher, Hubert; Schoepe, Wilfried

    2000-01-01

    Superfluid flow around an oscillating microsphere is investigated at temperatures down to 25 mK. Stable laminar flow below a critical velocity and turbulence at large drives are found to be separated below 0.5 K by an intermediate range of driving forces where the flow is unstable, intermittently switching between laminar and turbulent phases. We have recorded time series of this switching phenomenon and have made a statistical analysis of the switching probability. The mean lifetime of the t...

  9. Influence of Feeding Mode on Flow and Temperature Field for Twin Roll Strip Casting Process

    Institute of Scientific and Technical Information of China (English)

    MIAO Yu-chuan; XU Jian-zhong; WANG Guo-dong; LIU Xiang-hua

    2003-01-01

    A three-dimensional finite element method was developed to simulate the fluid flow, heat transfer and solidification for twin roll strip casting. An improved two-equation κ-ε model was used to incorporate the turbulence in fluid flow. The influence of vertical feeding and submerged entry nozzle feeding on the flow and temperature field was discussed. The optimum submersion depth and entry angle of submerged nozzle were obtained through comparison of the simulation results.

  10. Interstellar Gas Flow Vector and Temperature Determination over 5 Years of IBEX Observations

    International Nuclear Information System (INIS)

    The Interstellar Boundary Explorer (IBEX) observes the interstellar neutral gas flow trajectories at their perihelion in Earth's orbit every year from December through early April, when the Earth's orbital motion is into the oncoming flow. These observations have defined a narrow region of possible, but very tightly coupled interstellar neutral flow parameters, with inflow speed, latitude, and temperature as well-defined functions of inflow longitude. The best- fit flow vector is different by ≈ 3° and lower by ≈ 3 km/s than obtained previously with Ulysses GAS, but the temperature is comparable. The possible coupled parameter space reaches to the previous flow vector, but only for a substantially higher temperature (by ≈ 2000 K). Along with recent pickup ion observations and including historical observations of the interstellar gas, these findings have led to a discussion, whether the interstellar gas flow into the solar system has been stable or variable over time. These intriguing possibilities call for more detailed analysis and a longer database. IBEX has accumulated observations over six interstellar flow seasons. We review key observations and refinements in the analysis, in particular, towards narrowing the uncertainties in the temperature determination. We also address ongoing attempts to optimize the flow vector determination through varying the IBEX spacecraft pointing and discuss related implications for the local interstellar cloud and its interaction with the heliosphere

  11. Heat flow, depth–temperature variations and stored thermal energy for enhanced geothermal systems in Canada

    International Nuclear Information System (INIS)

    In order to help assessment of enhanced geothermal energy potential in Canada, we constructed a new series of heatflow and depth–temperature distribution maps (down to 10 km). We focus on high-temperature resources (>150 °C) capable of electrical production. Maps presented show large temperature variability, related mainly to heat flow patterns. The highest temperatures occur in western and northern Canada. Here temperatures greater than 150 °C, required for enhanced geothermal systems (EGS), can be reached at reasonable drilling depths of <5 km. Heat flow, by itself however, is not a sufficient tool to predict areas of high energy content. A combination of thick low thermal conductivity sedimentary blankets and moderate to high heat flow areas can generate targets that are as favorable as regions with high conductivity and high heat flow. Some moderate heat flow areas in the deeper parts of the Western Canada Sedimentary Basin have heat content comparable to high heat flow zones of the the Canadian Cordillera. The magnitude of in-place thermal energy available for future heat 'mining/farming' was esitmated throughout Canada by calculating heat released through cooling a defined rock volume through a fixed temperature change. These estimates show the first-order appoximation of available geothermal heat content. The fraction of true heat energy available will be as low as 0.02 of these values. However, even this more limited energy production could be large enough to be a considerable future renewable energy resource for Canada

  12. Gas-source MBE growth and n-type doping of AlGaAs using TEG, TEA, AsH 3 and Si 2H 6

    Science.gov (United States)

    Fujii, T.; Ando, H.; Sandhu, A.; Ishikawa, H.; Sugiyama, Y.

    1991-01-01

    We have studied gas-source molecular beam epitaxy (GSMBE) growth and n-type doping of AlGaAs using triethylgallium, triethylaluminum, arsine (AsH 3) and disilane (Si 2H 6), focusing on (1) the effect of substrate temperature (520-690°C) and AsH 3 flow rate (2-7 SCCM) on the carbon and oxygen incorporation of Al xGa 1- xAs ( x ˜ 0.28), and (2) the variation of the carrier concentration of n-type Al xGa 1- xAs ( x = 0-0.28) with Si 2H 6 flow rate (0.4-10 SCCM). The carbon concentration decreased with increasing substrate temperature up to 610°C, then increased with increasing substrate temperature using an AsH 3 flow rate of 2 SCCM. Below 610°C, an increase in AsH 3 flow rate resulted in a reduction in the carbon concentration. We obtained a carbon concentration of 1 × 10 18 cm -3 at a substrate temperature of 520°C and an AsH 3 flow rate of 7 SCCM. The addition of molecular hydrogen was found to further reduce the carbon concentration, and the lowest value obtained was 8.2 × 10 17 cm -3 at a substrate temperature of 520°C using 4 SCCM AsH 3 and 4.5 SCCM of molecular hydrogen. The oxygen concentration was not affected by the substrate temperature, but showed a slight decrease with increasing AsH 3 flow rate. The lowest oxygen concentration was 2.5 × 10 17 cm -3 at 7 SCCM AsH 3 flow rate. The variation of the hole concentration with growth conditions was similar to that observed for carbon. The 4.2 K photoluminescence was dominated by a free-to-bound emission having a full-width-at-half-maximum of 18 meV, which is thought to be related to shallow carbon acceptors. Si 2H 6 was shown to be a suitable cold n-type gaseous dopant source for GSMBE growth of AlGaAs. The carrier concentration of the n-type Al xGa 1- xAs ( x = 0-0.28) epilayer was reproducibly controlled between 5 × 10 17 and 2 × 10 18 cm -3.

  13. A Temperature-Profile Method for Estimating Flow Processes in Geologic Heat Pipes

    International Nuclear Information System (INIS)

    Above-boiling temperature conditions, as encountered, for example, in geothermal reservoirs and in geologic repositories for the storage of heat-producing nuclear wastes, may give rise to strongly altered liquid and gas flow processes in porous subsurface environments. The magnitude of such flow perturbation is extremely hard to measure in the field. We therefore propose a simple temperature-profile method that uses high-resolution temperature data for deriving such information. The energy that is transmitted with the vapor and water flow creates a nearly isothermal zone maintained at about the boiling temperature, referred to as a heat pipe. Characteristic features of measured temperature profiles, such as the differences in the gradients inside and outside of the heat pipe regions, are used to derive the approximate magnitude of the liquid and gas fluxes in the subsurface, for both steady-state and transient conditions

  14. Plastic flow behavior of a Ti-Al-Nb-Mn alloy at high temperatures

    International Nuclear Information System (INIS)

    High-temperature deformation of a gamma TiAl-based alloy containing 49.5 pct Al, 2.5 pct Nb and 1.1 pct Mn is studied using the constant-strain-rate isothermal compression-test technique. Axisymmetric tests were conducted in the strain rate range 0.001 to 10.0/s and at temperatures ranging from 1000 to 1400 C. The flow curves obtained at temperatures below 1250 C exhibit significant flow softening. This is correlated with the occurrence of shear localization, dynamic recrystallization, and wedge cracking. The flow-stress data are analyzed in terms of the strain-rate and temperature sensitivity. Strain-rate sensitivity decreases continuously with an increase in the strain rate and a decrease in the test temperature. In contrast, temperature sensitivity decreases with an increase in strain rate at all temperatures above 1050 C. A constitutive relationship between flow stress and the temperature-compensated strain rate is found to be valid in the temperature range 1000-1250 C. 20 refs

  15. Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer

    Science.gov (United States)

    Lu, N.; Ge, S.

    1996-01-01

    By including the constant flow of heat and fluid in the horizontal direction, we develop an analytical solution for the vertical temperature distribution within the semiconfining layer of a typical aquifer system. The solution is an extension of the previous one-dimensional theory by Bredehoeft and Papadopulos [1965]. It provides a quantitative tool for analyzing the uncertainty of the horizontal heat and fluid flow. The analytical results demonstrate that horizontal flow of heat and fluid, if at values much smaller than those of the vertical, has a negligible effect on the vertical temperature distribution but becomes significant when it is comparable to the vertical.

  16. Effects of non-uniform core flow on peak cladding temperature: MOXY/SCORE sensitivity calculations

    International Nuclear Information System (INIS)

    The MOXY/SCORE computer program is used to evaluate the potential effect on peak cladding temperature of selective cooling that may result from a nonuniform mass flux at the core boundaries during the blowdown phase of the LOFT L2-4 test. The results of this study indicate that the effect of the flow nonuniformity at the core boundaries will be neutralized by a strong radial flow redistribution in the neighborhood of core boundaries. The implication is that the flow nonuniformity at the core boundaries has no significant effect on the thermal-hydraulic behavior and cladding temperature at the hot plane

  17. Effects of non-uniform core flow on peak cladding temperature: MOXY/SCORE sensitivity calculations

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S.C.

    1979-08-15

    The MOXY/SCORE computer program is used to evaluate the potential effect on peak cladding temperature of selective cooling that may result from a nonuniform mass flux at the core boundaries during the blowdown phase of the LOFT L2-4 test. The results of this study indicate that the effect of the flow nonuniformity at the core boundaries will be neutralized by a strong radial flow redistribution in the neighborhood of core boundaries. The implication is that the flow nonuniformity at the core boundaries has no significant effect on the thermal-hydraulic behavior and cladding temperature at the hot plane.

  18. Heat and moisture flow in concrete as a function of temperature

    Science.gov (United States)

    Hundt, J.

    1978-01-01

    Due to temperature, reactors in operation cause heat and moisture flows in the thick walled prestressed pressure vessels. These flows were studied in three beams of concrete made with crushed limestone aggregate, and in three beams made of crushed gravel/sand aggregate. The flow phenomena were related to the structural development of the concrete by determining the amount of non-evaporatable water, the total porosity, and the pore size distribution. Local temperature and moisture conditions also influenced the technical properties. Compressive strength, changes in length due to shrinkage and contraction, thermal expansion, and thermal conductivity were determined.

  19. Fly ash carbon passivation

    Science.gov (United States)

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  20. Coupled model of deformation and gas flow process with temperature and slippage effect

    Directory of Open Access Journals (Sweden)

    Chunhui ZHANG

    2015-06-01

    Full Text Available The effects of temperature, slippage effect and effective stress of coal on the coupled mechanism of deformation and gas glow are key issues to control coal and gas outburst and design the methane recovery engineering. Firstly, intact coal from Huaxing mine in Jilin Province is crushed and coal briquette specimen are made. Then the tri-axial coupled test setup of the deformation, gas flow and temperature developed by ourselves is adopted to investigate the effects of pore pressure, effective stress and temperature on the permeability of coal briquette specimen. The results show that: 1 Under the condition of low pore pressure, the permeability first reduces with pore pressure increasing, then at a threshold of pore pressure it rises with pore pressure increasing, which is called “slippage effect”. 2 The effective confining stress significantly influences the permeability. With increasing effective confining stress, the space of pores and cracks are compressed and the permeability reduces. 3 The temperature significantly influences the permeability and the permeability decreases with temperature increasing. The main reason is that the space of pores and cracks is compressed due to the temperature stress. Because of the constraint around, temperature compressive stress appears in internal coal samples. Coal pore and fracture space is compressed, and the sample permeability decreases. Besides, the viscosity of gas increases with temperature increasing. It decreases the trend of coal permeability . The temperature influence on coal permeability approximates to linear relationship. 4 The empirical permeability evolution equation with varying temperature, effective stress and slippage effects is presented. The coal is viewed as elastic medium, combined with effective stress principle and the empirical permeability equation, the coupled model of deformation and gas flow with varying temperature and slippage effects is built. Furthermore, the code

  1. Chemical composition in relation with biomass ash structure

    Science.gov (United States)

    Holubcik, Michal; Jandacka, Jozef

    2014-08-01

    Biomass combustion can be more complicated like combustion of fossil fuels because it is necessary to solve problems with lower ash melting temperature. It can cause a lot of problems during combustion process. Chemical composition of biomass ash has great impact on sinters and slags creation in ash because it affects structure of heated ash. In this paper was solved relation between chemical composition and structure of heated ash from three types of biomass (spruce wood, miscanthus giganteus and wheat straw). Amount of SiO2, CaO, MgO, Al2O3 and K2O was determined. Structure of heated ash was optically determined after heating to 1000 °C or 1200 °C. Results demonstrated that chemical composition has strong effect on structure and color of heated ash.

  2. Flow stress and material model study at high strain rate and low temperature

    Science.gov (United States)

    Kandasamy, R.; Brar, N. S.

    1994-07-01

    The flow stress of M200 maraging steel, C1008 steel, and 6061-T6 aluminum at low temperatures to 123 K and at a strain rate of about 103 s-1 is measured using split Hopkinson bar (SHB). Liquid nitrogen is used to cool the specimen to the desired temperature. The flow stress of M200 increased to 1.93 GPa at 123 K, an increase of 22 percent compared to 1.58 GPa at room temperature. In the case of 6061-T6 aluminum the flow stress remains at about 390 MPa at temperatures in the range 293 to 123 K. For C1008 steel, the flow stress increased to 860 MPa at 123 K from its room temperature value of 610 MPa. The failure strain for C1008 steel at 123 K was 0.02, compared to 0.2 at room temperature, suggesting a ductile to brittle transition. The Johnson-Cook material model constant ``m'', which accounts for temperature effect, is 0.5 for C1008 at temperatures in the range 123 K to 950 K.

  3. DNS of channel flow with conjugate heat transfer - Budgets of turbulent heat fluxes and temperature variance

    OpenAIRE

    Flageul Cédric, Benhamadouche Sofiane, Lamballais Éric, Laurence Dominique.

    2014-01-01

    The present work provides budgets of turbulent heat fluxes and temperature variance for a channel flow with different thermal boundary conditions: an imposed temperature, an imposed heat flux and with conjugate heat transfer combined with an imposed heat flux at the outer wall.

  4. Development of an ultrasonic flow and temperature measurement system for pressurized water reactors

    International Nuclear Information System (INIS)

    In U.S. nuclear plants, primary coolant flow and reactor thermal power are calculated from a measurement of feedwater flow to the steam generator combined with knowledge of steam generator heat transfer characteristics nd measurement of hot leg temperature by resistance temperature detectors (RTDs). The calculation of plant thermal output is complicated by an indirect measurement of primary coolant mass flow rate and thermal streaming in the region where hot leg temperature is typically measured. Uncertainty in the thermal output calculation results from uncertainties in steam generator characteristics, in the hot leg temperature due to thermal streaming, and in fouling of venturi nozzles used for feedwater flow measurement. This in turn leads to operation of power plants ar lower levels of efficiency. The Electric Power Research Institute (EPRI) has on ongoing project to develop a prototype system to directly measure primary coolant flow rate and bulk average temperature using ultrasonic transducers externally mounted on the pipe. The topic of this paper is a summary of the project experience in developing this system. The technology being developed in this project is based in part upon previously existing ultrasonic feedwater flow measurement technology developed by MPR Associates and Caldon, Inc EPRI is a non-profit company performing research for U.S. and international electric power utilities. (authors)

  5. Prediction of Stratified Flow Temperature Profiles in a Fully Insulated Environment

    Directory of Open Access Journals (Sweden)

    Ahmad S. Awad

    2014-07-01

    Full Text Available The aim of the study is to present an analytical model to predict the temperature profiles in thermal stratified environment. Thermal stratification is encountered in many situations. The flow of contaminants and hydrocarbons in environment often get stratified. The prediction of temperature profiles and flow characteristics are essential for HVAC applications, environment and energy management. The temperature profiles in the stratified region are successfully obtained, in terms of flow-operating functions. The analytical model agrees well with the published experimental data as well as the related closed-form solutions, which is helpful for HVAC applications. The model will be further developed and incorporated within a numerical model in order to investigate the flow field characteristics and establish correlations for a wide range of parameters.

  6. Combined pressure and temperature distortion effects on internal flow of a turbofan engine

    Science.gov (United States)

    Braithwaite, W. M.; Soeder, R. H.

    1979-01-01

    The flow characteristics obtained experimentally for the compression of a 2-spool TF30-P-3 turbofan engine operating with 180 grad combined pressure and temperature distortion in the inlet flow are presented. The analytical model (Mazzawy and Banks, 1976), 'tuned' during Lewis testing, was used for pretest predictions of the effects that these distortions would have on the engine flow characteristics and the limiting distortion values. The effect of inlet flow distortion on the performance of the engine is discussed, including: (1) the flow between a screen mounted in the inlet duct and the inlet guide vanes; (2) the flow through the compression system; and (3) the effects of the combined distortion and its orientation on the compressor stability limits. It is concluded that the model used in this program was capable of predicting the effects of total pressure, total temperature and combined total pressure-total temperature distortions in terms of flow profiles, inlet flow angles and attenuation of the distortions through the compressor system. It was also capable of predicting the trends of the limiting values experienced with various orientations of the combined distortions.

  7. Forearm blood flow during body temperature transients produced by leg exercise

    Science.gov (United States)

    Wenger, C. B.; Roberts, M. F.; Stolwijk, J. A. J.; Nadel, E. R.

    1975-01-01

    Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 C and vapor pressures of less than 18 torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow was measured by electrocapacitance plethysmography. Data are well accounted for by a linear equation independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise.

  8. High temperature flow behaviour of SiC reinforced lithium aluminosilicate composites

    Indian Academy of Sciences (India)

    Santanu Das; V S R Murthy; G S Murty

    2001-04-01

    The compressive flow behaviour of lithium aluminosilicate (LAS) glass, with and without SiC particulate reinforcements, was studied. The LAS glass crystallized to spodumene during high-temperature testing. The flow behaviour of LAS glass changed from Newtonian to non-Newtonian due to the presence of crystalline phase. Further, with the addition of 40 vol.% SiC additions, the strain rate sensitivity of flow stress decreased. While the activation energy for flow in LAS was 300 kJ/mole, it increased to 995 kJ/mole with the addition of 40 vol.% SiC reinforcements.

  9. Method for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder

    Indian Academy of Sciences (India)

    Sulardjaka; Jamasri; M W Wildan; Kusnanto

    2011-07-01

    A novel process for increasing -SiC yield on solid state reaction of coal fly ash and micro powder activated carbon powder has been proposed. -SiC powder was synthesized at temperature 1300°C for 2 h under vacuum condition with 1 l/min argon flow. Cycling synthesis process has been developed for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder. Synthesized products were analyzed by XRD with Cu-K radiation, FTIR spectrometer and SEM fitted with EDAX. The results show that the amount of relative -SiC is increased with the number of cycling synthesis.

  10. Plasma flow crisis and limiting electron temperature in a vacuum arc and in axial magnetic field

    International Nuclear Information System (INIS)

    One studied possibility of supersonic motion of cathode plasma in a weak-current vacuum arc placed in axial magnetic field. Increase of electron temperature is shown to result inevitably in reduction of plasma speed up to sonic speed, that is, flow crisis. One derived dependence of the boundary length of plasma stationary flow on magnetic field. The maximum attainable electron temperature of plasma was determined to be governed by ion initial energy and to be equal to the triple value of electron temperature within cathode spot range

  11. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans

    OpenAIRE

    Wingo, Jonathan E.; David A Low; Keller, David M.; Brothers, R. Matthew; Shibasaki, Manabu; Crandall, Craig G.

    2010-01-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdial...

  12. Study of glass ceramic material on the base of ash group simulating slag of plasma shaft furnace for high temperature reprocessing of radioactive wastes

    International Nuclear Information System (INIS)

    Using the methods of X-ray diffraction, differential thermal and micro-probe analysis it is shown that the processes of minerals formation and homogenization in ash residue based charge under the heating up to 1450 deg C take place with a high rate and completely finish during 10 minutes. Homogeneous materials containing besides glassy phase crystalline phases and metallic shots are formed in this process. The products obtained with fluxes (dolomite and clay) additions are more homogeneous than a flux-less fused slag. Losses of α-radioactive nuclides during the melting of ash residue at 1300 deg C do not exceed 1.5% and is likely attributed with the products of uranium decay. Hydrolytic stability of the slags estimated from the rate of α-radioactive elements lixiviation is on the level of (1.4-5.7)x10-4 g/(cm2 x day) at 95 deg C

  13. Hydrogen/Oxygen Reactions at High Pressures and Intermediate Temperatures: Flow Reactor Experiments and Kinetic Modeling

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Glarborg, Peter

    A series of experimental and numerical investigations into hydrogen oxidation at high pressures and intermediate temperatures has been conducted. The experiments were carried out in a high pressure laminar flow reactor at 50 bar pressure and a temperature range of 600–900 K. The equivalence ratio......, the mechanism is used to simulate published data on ignition delay time and laminar burning velocity of hydrogen. The flow reactor results show that at reducing, stoichiometric, and oxidizing conditions, conversion starts at temperatures of 750–775 K, 800–825 K, and 800–825 K, respectively. In oxygen...... atmosphere, ignition occurs at the temperature of 775–800 K. In general, the present model provides a good agreement with the measurements in the flow reactor and with recent data on laminar burning velocity and ignition delay time....

  14. Numerical investigation of a high-temperature counter-flow compact heat exchanger

    International Nuclear Information System (INIS)

    Very High Temperature Reactors (VHTRs) require high temperature, high integrity, and highly effective heat exchangers during normal and off-normal conditions. A class of compact plate-type heat exchanger, Printed Circuit Heat Exchangers (PCHEs) is being considered for use in VHTRs. In the current study, simplified and full-size PCHE models are investigated numerically using FluentTM software. The geometry considered in the study replicate the PCHEs that were fabricated using Alloy 617 plates for use in a high-temperature helium test facility at The Ohio State University. The cases considered are based upon the design conditions of the high-temperature test facility: operating pressure of 3 MPa, hot side inlet temperature of 1,173 K, cold side inlet temperature of 813 K, and mass flow rates ranging from 10 to 80 kg/h. The ranges of mass flow rates and temperatures correspond to laminar and laminar-to-turbulent transition flows in the PCHE flow passages. Heat transfer and pressure drop are evaluated in both models to provide preliminary performance data for the laboratory scale PCHEs to be operated at temperatures similar to those of the VHTRs. Local convective heat transfer coefficients are calculated for channels on the hot and cold sides and compared to published experimental results for the laminar flow cases and the Gnielinski correlation for the transition flow cases. The overall heat transfer coefficient ranges from 563-1,697 W/m2-K. The maximum pressure drop in this particular PCHE is found to be approximately 1.5% of the system operating pressure. The calculated convective heat transfer coefficients and pressure drop compare well with the models in the literature. (author)

  15. Temperature-Profile Methods for Estimating Thermally-Driven Flow Processes in Superheated Rocks

    Science.gov (United States)

    Birkholzer, J. T.

    2004-12-01

    In geologic repositories for storage of nuclear wastes, the heat generated by the decay of the radioactive waste may result in rock temperatures high enough to cause boiling conditions in the subsurface, which gives rise to strongly altered flow processes. These flow processes are characterized by (1) vapor production in the superheated zone close to the heat source, (2) pressure-driven vapor transport away from the heat source, (3) condensation in cooler regions, and (4) reflux of the condensate back to the heat source. Since the magnitude of such flow perturbation is extremely hard to measure in the field, we propose a simple temperature-profile method that uses high-resolution temperature data for deriving such information. The energy that is transmitted by the vapor-water reflux processes creates a nearly isothermal zone maintained at about the boiling temperature, referred to as a heat-pipe signature. Characteristic features of the temperature profile, such as the differences in the gradients inside and outside of this zone, can be used to derive the approximate magnitude of the vapor and water fluxes, for both steady-state and transient conditions. We present the theoretical basis for the proposed temperature-profile method, test the method in comparison with a semi-analytical solution of thermally-driven flow processes, and present a sample application using measured temperature profiles from an underground heater test.

  16. CO2 capture and sorbent regeneration performances of some wood ash materials

    International Nuclear Information System (INIS)

    Highlights: • Wood ash is tried as a new sorbent for CO2 capture from flue gas after combustion. • The CO2 capture capacity of wood ash is in the range of 0.35–0.54 mmol CO2/g. • The sorbent can be completely regenerated below 200 °C. • For the recycle of environmental pollutants, wood ash is a low cost CO2 sorbent. - Abstract: Wood ash, which is recognized as an environmental pollutant, is tried as a new material for CO2 capture in this work. Five wood ash samples obtained from different raw materials were chosen, and an experimental demonstration of the CO2 capture performances of these wood ash samples was present in detail in a modified fixed bed reactor system. The CO2 capture and the sorbent regeneration performances of wood ash were investigated under different conditions by changing the temperature, H2O concentration, gas flow rate and the heating rate. The CO2 capture capacities are in the range of 0.35–0.54 mmol CO2/g for different wood ash samples under the condition of 60 °C, 10% CO2 + 12% H2O. The CO2 capture processes contain two parts for these samples. One is the physical adsorption process, and another is the chemical reaction of K2CO3 with CO2 and H2O to form KHCO3, K2CO3·1.5H2O and K4H2(CO3)3·1.5H2O. The desired wood ash is proved to be regenerable and stable during 10-cycle CO2 sorption–desorption tests. The deactivation model and the Avrami–Erofeyev model are adopted to evaluate the CO2 sorption and desorption kinetics of this sample respectively. Considering the low cost, and the recycling of environmental pollutants, wood ash is a nice choice for CO2 capture

  17. Investigation on the Core Bypass Flow in a Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Yassin

    2013-10-22

    Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racks of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the

  18. Effects of intermittent flow and irradiance level on back reef Porites corals at elevated seawater temperatures

    Science.gov (United States)

    Smith, L.W.; Birkeland, C.

    2007-01-01

    Corals inhabiting shallow back reef habitats are often simultaneously exposed to elevated seawater temperatures and high irradiance levels, conditions known to cause coral bleaching. Water flow in many tropical back reef systems is tidally influenced, resulting in semi-diurnal or diurnal flow patterns. Controlled experiments were conducted to test effects of semi-diurnally intermittent water flow on photoinhibition and bleaching of the corals Porites lobata and P. cylindrica kept at elevated seawater temperatures and different irradiance levels. All coral colonies were collected from a shallow back reef pool on Ofu Island, American Samoa. In the high irradiance experiments, photoinhibition and bleaching were less for both species in the intermittent high-low flow treatment than in the constant low flow treatment. In the low irradiance experiments, there were no differences in photoinhibition or bleaching for either species between the flow treatments, despite continuously elevated seawater temperatures. These results suggest that intermittent flow associated with semi-diurnal tides, and low irradiances caused by turbidity or shading, may reduce photoinhibition and bleaching of back reef corals during warming events. ?? 2006 Elsevier B.V. All rights reserved.

  19. Paleoclimatic reconstructions in western Canada from borehole temperature logs: surface air temperature forcing and groundwater flow

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Grasby, S. E.; Ferguson, G.; Šafanda, Jan; Skinner, W.

    2006-01-01

    Roč. 2, č. 1 (2006), s. 1-10. ISSN 1814-9324 Institutional research plan: CEZ:AV0Z30120515 Keywords : palaeoclimatic reconstructions * Canada * borehole temperatures Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  20. Crustal heat flow measurements in western Anatolia from borehole equilibrium temperatures

    Science.gov (United States)

    Erkan, K.

    2014-01-01

    Results of a crustal heat flow analysis in western Anatolia based on borehole equilibrium temperatures and rock thermal conductivity data are reported. The dataset comprises 113 borehole sites that were collected in Southern Marmara and Aegean regions of Turkey in 1995-1999. The measurements are from abandoned water wells with depths of 100-150 m. Data were first classed in terms of quality, and the low quality data, including data showing effects of hydrologic disturbances on temperatures, were eliminated. For the remaining 34 sites, one meter resolution temperature-depth curves were carefully analyzed for determination of the background geothermal gradients, and any effects of terrain topography and intra-borehole fluid flow were corrected when necessary. Thermal conductivities were determined either by direct measurements on representative surface outcrop or estimated from the borehole lithologic records. The calculated heat flow values are 85-90 mW m-2 in the northern and central parts of the Menderes horst-graben system. Within the system, the highest heat flow values (> 100 mW m-2) are observed in the northeastern part of Gediz Graben, near Kula active volcanic center. The calculated heat flow values are also in agreement with the results of studies on the maximum depth of seismicity in the region. In the Menderes horst-graben system, surface heat flow is expected to show significant variations as a result of active sedimentation and thermal refraction in grabens, and active erosion on horst detachment zones. High heat flow values (90-100 mW m-2) are also observed in the peninsular (western) part of Çanakkale province. The heat flow anomaly here may be an extension of the high heat flow zone previously observed in the northern Aegean Sea. Moderate heat flow values (60-70 mW m-2) are observed in eastern part of Çanakkale and central part of Balıkesir provinces.

  1. Crustal heat flow measurements in western Anatolia from borehole equilibrium temperatures

    Directory of Open Access Journals (Sweden)

    K. Erkan

    2014-01-01

    Full Text Available Results of a crustal heat flow analysis in western Anatolia based on borehole equilibrium temperatures and rock thermal conductivity data are reported. The dataset comprises 113 borehole sites that were collected in Southern Marmara and Aegean regions of Turkey in 1995–1999. The measurements are from abandoned water wells with depths of 100–150 m. Data were first classed in terms of quality, and the low quality data, including data showing effects of hydrologic disturbances on temperatures, were eliminated. For the remaining 34 sites, one meter resolution temperature-depth curves were carefully analyzed for determination of the background geothermal gradients, and any effects of terrain topography and intra-borehole fluid flow were corrected when necessary. Thermal conductivities were determined either by direct measurements on representative surface outcrop or estimated from the borehole lithologic records. The calculated heat flow values are 85–90 mW m−2 in the northern and central parts of the Menderes horst-graben system. Within the system, the highest heat flow values (> 100 mW m−2 are observed in the northeastern part of Gediz Graben, near Kula active volcanic center. The calculated heat flow values are also in agreement with the results of studies on the maximum depth of seismicity in the region. In the Menderes horst-graben system, surface heat flow is expected to show significant variations as a result of active sedimentation and thermal refraction in grabens, and active erosion on horst detachment zones. High heat flow values (90–100 mW m−2 are also observed in the peninsular (western part of Çanakkale province. The heat flow anomaly here may be an extension of the high heat flow zone previously observed in the northern Aegean Sea. Moderate heat flow values (60–70 mW m−2 are observed in eastern part of Çanakkale and central part of Balıkesir provinces.

  2. Temperature rise of He Ⅱ forced flow and its negative Joule-Thomson effect

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu; JU Yong-lin; ZHENG Qing-rong; LU Xue-sheng; GU An-zhong

    2009-01-01

    The temperature rise of He Ⅱ transfer system due to the negative Joule-Thomson (JT) effect is one of the major problems in the He Ⅱ forced flow system design. Negative Joule-Thomson effect of the He Ⅱ forced flow was analyzed and calculated in this paper. The temperature rise due to the heat leak along the transfer pipeline was calculated by the simplified equation and was modified by considering the negative Joule-Thomson effect. The modified results were compared with the temperature rise obtained by non-linear differential equations with consideration of the pressure gradient. The results show that the pressure gradient has strong effect on the temperature distribution. The modified results are in good agreement with the values calculated by the complicated equation, which verifies the effectiveness of the simplified equation in calculating the temperature rise when the negative JT effect of He Ⅱ is known.

  3. Transient Approach to Radiative Heat Transfer Free Convection Flow with Ramped Wall Temperature

    Directory of Open Access Journals (Sweden)

    R.R Patra

    2012-01-01

    Full Text Available The effect of radiation on natural convection incompressible viscous fluid near a vertical flat plate with ramped wall temperature has been studied. An analytical solution of the governing equation has been obtained by employing Laplace transform technique. It is examined that two different solutions for the fluid velocities, one valid for fluids of Prandtl number Pr  different from 1 Ra , Ra being the radiation parameter and the other for which the Prandtl number equal to 1 Ra . The variations of velocities and fluid temperature are presented graphically. Furthermore, the radiative heat transfer on natural convection flow near a ramped plate temperature has been compared with the flow near a plate with the constant wall temperature. It is found that an increase in radiation parameter leads to rise the fluid velocity as well as temperature.

  4. Debris flow grain size scales with sea surface temperature over glacial-interglacial timescales

    Science.gov (United States)

    D'Arcy, Mitch; Roda Boluda, Duna C.; Whittaker, Alexander C.; Araújo, João Paulo C.

    2015-04-01

    Debris flows are common erosional processes responsible for a large volume of sediment transfer across a range of landscapes from arid settings to the tropics. They are also significant natural hazards in populated areas. However, we lack a clear set of debris flow transport laws, meaning that: (i) debris flows remain largely neglected by landscape evolution models; (ii) we do not understand the sensitivity of debris flow systems to past or future climate changes; and (iii) it remains unclear how to interpret debris flow stratigraphy and sedimentology, for example whether their deposits record information about past tectonics or palaeoclimate. Here, we take a grain size approach to characterising debris flow deposits from 35 well-dated alluvial fan surfaces in Owens Valley, California. We show that the average grain sizes of these granitic debris flow sediments precisely scales with sea surface temperature throughout the entire last glacial-interglacial cycle, increasing by ~ 7 % per 1 ° C of climate warming. We compare these data with similar debris flow systems in the Mediterranean (southern Italy) and the tropics (Rio de Janeiro, Brazil), and find equivalent signals over a total temperature range of ~ 14 ° C. In each area, debris flows are largely governed by rainfall intensity during triggering storms, which is known to increase exponentially with temperature. Therefore, we suggest that these debris flow systems are transporting predictably coarser-grained sediment in warmer, stormier conditions. This implies that debris flow sedimentology is governed by discharge thresholds and may be a sensitive proxy for past changes in rainfall intensity. Our findings show that debris flows are sensitive to climate changes over short timescales (≤ 104 years) and therefore highlight the importance of integrating hillslope processes into landscape evolution models, as well as providing new observational constraints to guide this. Finally, we comment on what grain size

  5. Mass flow discharge and total temperature characterisation of a pyrotechnic gas generator formulation for airbag systems

    Energy Technology Data Exchange (ETDEWEB)

    Neutz, Jochen; Koenig, Andreas [Fraunhofer Institut fuer Chemische Technologie ICT, Pfinztal (Germany); Knauss, Helmut; Jordan, Sebastian; Roediger, Tim; Smorodsky, Boris [Universitaet Stuttgart (Germany). Institut fuer Aerodynamik und Gasdynamik; Bluemcke, Erich Walter [AUDI AG, Department I/EK-523, Ingolstadt (Germany)

    2009-06-15

    The mass flow characteristics of gas generators for airbag applications have to comply with a number of requirements for an optimal deployment of the airbag itself. Up to now, the mass flow was determined from pressure time histories of so-called can tests. This procedure suffers from the missing knowledge on the temperature of the generated gas entering the can. A new test setup described in this paper could overcome this problem by providing highly time resolved information on the gas's total temperature and the mass flow of the generator. The test setup consisted of a combustion chamber with a specially designed Laval nozzle in combination with a temperature sensor of high time resolution. The results showed a high time resolved temperature signal, which was disturbed by the formation of a slag layer on the sensor. Plausibility considerations with experimentally and thermodynamically determined combustion temperatures led to satisfying results for the overall temperature as characteristic parameter of airbag inflating gases flows from pyrotechnics. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Recovering germanium from coal ash by chlorination with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of enriching germanium from coal ash was developed. The process involves in mixing the coal ash and ammonium chloride and then roasting the mixture to produce germanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germanium oxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH4Cl/coal ash is 0.15, roasting temperature 400℃ and roasting time 90 min.

  7. Ash chemistry and sintering, verification of the mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J. [Aabo Akademi, Turku (Finland)

    1996-12-01

    In this project four sintering mechanisms have been studied, i.e., partial melting with a viscous liquid, partial melting with a non-viscous liquid, chemical reaction sintering and solid state sintering. The work has aimed at improving the understanding of ash sintering mechanisms and quantifying their role in combustion and gasification. The work has been oriented in particular on the understanding of biomass ash behavior. The work has not directly focused on any specific technical application. However, results can also be applied on other fuels such as brown coal, petroleum coke, black liquor and different types of wastes (PDF, RDF, MSW). In one part of study the melting behavior was calculated for ten biomass ashes and compared with lab measurements of sintering tendencies. The comparison showed that the T{sub 15} temperatures, i.e. those temperatures at which the ashes contained 15 % molten phase, correlated fairly well with the temperature at which the sintering measurements detected sintering. This suggests that partial melting can be predicted fairly accurate for some ashes already with the today existing thermodynamic calculation routines. In some cases, however the melting calculations did not correlate with the detected sintering temperatures. In a second part detailed measurements on ash behavior was conducted both in a semi full scale CFB and a lab scale FBC. Ashes and deposits were collected and analyzed in several different ways. These analyses show that the ash chemistry shifts radically when the fuel is shifted. Fuels with silicate based ashes behaved totally different than those with an oxide or salt based ash. The chemistry was also affected by fuel blending. The ultimate goal has been to be able to predict the ash thermal behavior during biomass thermal conversion, using the fuel and ash elemental analyses and a few operational key parameters as the only input data. This goal has not yet today been achieved. (author)

  8. Effects of operating temperature on the performance of vanadium redox flow batteries

    International Nuclear Information System (INIS)

    Highlights: • The effect of the operating temperature on the VRFB’s performance is studied. • The voltage efficiency and peak power density increases with temperature. • High temperatures aggravate the coulombic efficiency drop and the capacity decay. • The outcomes suggest that thermal management of operating VRFBs is essential. - Abstract: For an operating flow battery system, how the battery’s performance varies with ambient temperatures is of practical interest. To gain an understanding of the general thermal behavior of vanadium redox flow batteries (VRFBs), we devised and tested a laboratory-scale single VRFB by varying the operating temperature. The voltage efficiency of the VRFB is found to increase from 86.5% to 90.5% at 40 mA/cm2 when the operating temperature is increased from 15 °C to 55 °C. The peak discharge power density is also observed to increase from 259.5 mW/cm2 to 349.8 mW/cm2 at the same temperature increment. The temperature increase, however, leads to a slight decrease in the coulombic efficiency from 96.2% to 93.7% at the same temperature increments. In addition, the capacity degradation rate is found to be higher at higher temperatures

  9. Evaluation of water cooled supersonic temperature and pressure probes for application to 2000 F flows

    Science.gov (United States)

    Lagen, Nicholas T.; Seiner, John M.

    1990-01-01

    The development of water cooled supersonic probes used to study high temperature jet plumes is addressed. These probes are: total pressure, static pressure, and total temperature. The motivation for these experiments is the determination of high temperature supersonic jet mean flow properties. A 3.54 inch exit diameter water cooled nozzle was used in the tests. It is designed for exit Mach 2 at 2000 F exit total temperature. Tests were conducted using water cooled probes capable of operating in Mach 2 flow, up to 2000 F total temperature. Of the two designs tested, an annular cooling method was chosen as superior. Data at the jet exit planes, and along the jet centerline, were obtained for total temperatures of 900 F, 1500 F, and 2000 F, for each of the probes. The data obtained from the total and static pressure probes are consistent with prior low temperature results. However, the data obtained from the total temperature probe was affected by the water coolant. The total temperature probe was tested up to 2000 F with, and without, the cooling system turned on to better understand the heat transfer process at the thermocouple bead. The rate of heat transfer across the thermocouple bead was greater when the coolant was turned on than when the coolant was turned off. This accounted for the lower temperature measurement by the cooled probe. The velocity and Mach number at the exit plane and centerline locations were determined from the Rayleigh-Pitot tube formula.

  10. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    International Nuclear Information System (INIS)

    Highlights: ► Element release during fly ash extraction experiments controlled by mineralogy. ► Strontium isotopes in fly ash are not homogenized during coal combustion. ► Element correlations with 87Sr/86Sr indicate chemically resistant silicate phase. ► Sr isotopes can uniquely identify fly ash fluids leaking into the environment. - Abstract: The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in 87Sr/86Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface

  11. Heat-flow and temperature control in Tian–Calvet microcalorimeters: toward higher detection limits

    International Nuclear Information System (INIS)

    Strategies based on the principle of heat flow and temperature control were implemented, and experimentally tested, to increase the sensitivity of a Tian–Calvet microcalorimeter for measuring heats of adsorption. Here, both heat-flow and temperature control schemes were explored to diminish heater-induced thermal variations within the heat sink element, hence obtaining less noise in the baseline signal. PID controllers were implemented within a closed-loop system to perform the control actions in a calorimetric setup. The experimental results demonstrate that the heat flow control strategy provided a better baseline stability when compared to the temperature control. The effects on the results stemming from the type of power supply used were also investigated

  12. High temperature, high pressure gas loop - the Component Flow Test Loop (CFTL)

    International Nuclear Information System (INIS)

    The high-pressure, high-temperature, gas-circulating Component Flow Test Loop located at Oak Ridge National Laboratory was designed and constructed utilizing Section III of the ASME Boiler and Pressure Vessel Code. The quality assurance program for operating and testing is also based on applicable ASME standards. Power to a total of 5 MW is available to the test section, and an air-cooled heat exchanger rated at 4.4 MW serves as heat sink. The three gas-bearing, completely enclosed gas circulators provide a maximum flow of 0.47 m3/s at pressures to 10.7 MPa. The control system allows for fast transients in pressure, power, temperature, and flow; it also supports prolonged unattended steady-state operation. The data acquisition system can access and process 10,000 data points per second. High-temperature gas-cooled reactor components are being tested

  13. High temperature, high pressure gas loop - the Component Flow Test Loop (CFTL)

    Energy Technology Data Exchange (ETDEWEB)

    Gat, U.; Sanders, J.P.; Young, H.C.

    1984-01-01

    The high-pressure, high-temperature, gas-circulating Component Flow Test Loop located at Oak Ridge National Laboratory was designed and constructed utilizing Section III of the ASME Boiler and Pressure Vessel Code. The quality assurance program for operating and testing is also based on applicable ASME standards. Power to a total of 5 MW is available to the test section, and an air-cooled heat exchanger rated at 4.4 MW serves as heat sink. The three gas-bearing, completely enclosed gas circulators provide a maximum flow of 0.47 m/sup 3//s at pressures to 10.7 MPa. The control system allows for fast transients in pressure, power, temperature, and flow; it also supports prolonged unattended steady-state operation. The data acquisition system can access and process 10,000 data points per second. High-temperature gas-cooled reactor components are being tested.

  14. Changes of the ash structure

    Science.gov (United States)

    Peer, Václav; Friedel, Pavel; Janša, Jan

    2016-06-01

    The aim of the article is to appraisal of the changes in the structure of the ash due to the addition of compounds capable of the eutectics composition change. For the transformation were used limestone and dolomite dosed in amounts of 2, 5 and 10 wt.% with pellets of spruce wood, willow wood and refused derived fuel. Combustion temperatures of the mixtures were adjusted according to the temperatures reached during the using of fuels in power plants, i.e. 900, 1000, 1100 and 1200 °C.

  15. Simultaneous measurements of plasma flow and ion temperature using the asymmetric double probe

    International Nuclear Information System (INIS)

    The asymmetric double probe method is extended to measure not only the ion temperature but also plasma flow in the tokamak edge plasma under a strong magnetic field. The plasma flow or the Mach number is determined by the ratio of ion saturation currents of the double probe pins, where the axes of the cylindrical pins are oriented perpendicular to the magnetic field and face up-or downstream. An experiment was performed in the JFT-2M tokamak. (author)

  16. Cleanup Verification Package for the 126-F-1, 184-F Powerhouse Ash Pit

    Energy Technology Data Exchange (ETDEWEB)

    S. W. Clark and H. M Sulloway

    2007-10-31

    This cleanup verification package documents completion of remedial action for the 126-F-1, 184-F Powerhouse Ash Pit. This waste site received coal ash from the 100-F Area coal-fired steam plant. Leakage of process effluent from the 116-F-14 , 107-F Retention Basins flowed south into the ash pit, contaminating the northern portion.

  17. Cleanup Verification Package for the 126-F-1, 184-F Powerhouse Ash Pit

    International Nuclear Information System (INIS)

    This cleanup verification package documents completion of remedial action for the 126-F-1, 184-F Powerhouse Ash Pit. This waste site received coal ash from the 100-F Area coal-fired steam plant. Leakage of process effluent from the 116-F-14 , 107-F Retention Basins flowed south into the ash pit, contaminating the northern portion

  18. Cleanup Verification Package for the 126-F-1, 184-F Powerhouse Ash Pit

    Energy Technology Data Exchange (ETDEWEB)

    S. W. Clark and H. M. Sulloway

    2007-09-26

    This cleanup verification package documents completion of remedial action for the 126-F-1, 184-F Powerhouse Ash Pit. This waste site received coal ash from the 100-F Area coal-fired steam plant. Leakage of process effluent from the 116-F-14 , 107-F Retention Basins flowed south into the ash pit, contaminating the northern portion.

  19. Analysis of Temperature and Plastic Flow during Friction Stir Spot Welding Using Particle Method

    Science.gov (United States)

    Hirasawa, Shigeki; Badarinarayan, Harsha; Okamoto, Kazutaka; Tomimura, Toshio; Kawanami, Tsuyoshi; Hirano, Shigeki

    Friction stir spot welding (FSSW) is a new metal-joining process, and a numerical simulation code to calculate optimal welding conditions is desired. In this paper, we analyzed temperature distribution and plastic deformation flow during the FSSW process with the fluid flow model and the elastic-plastic deformation model using the particle method. Spot welds are made with a cylindrical pin tool having flat shoulder with a fixed tool rotational speed. Simulation results predict an axisymmetric temperature distribution with the temperature below the tool in the region of 300 °C. The material flow predicted by the elastic-plastic deformation model is similar to experimental results. The model predicts the material flow at the pin periphery is in the upward direction. Near the shoulder, there are two flow patterns observed - beneath the shoulder, the material is pushed downward due to the force acting from the shoulder face, whereas on the shoulder periphery the material flows upward and outward due to extrusion of the material that is caused by the shoulder plunge. This extruded material shows up on the specimen surface as burr.

  20. Prediction of high temperature flow stress in 9Cr-1Mo ferritic steel during hot compression

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, S.A. [Materials Technology Division, Indira Gandhi Centre for Atomic Research, Dept of Atomic Energy, Kalpakkam 603102, Tamil Nadu (India); Phaniraj, C., E-mail: phani@igcar.gov.in [Materials Technology Division, Indira Gandhi Centre for Atomic Research, Dept of Atomic Energy, Kalpakkam 603102, Tamil Nadu (India); Ravishankar, C.; Bhaduri, A.K.; Sivaprasad, P.V. [Materials Technology Division, Indira Gandhi Centre for Atomic Research, Dept of Atomic Energy, Kalpakkam 603102, Tamil Nadu (India)

    2011-12-15

    Constitutive analysis was performed on the experimental true stress-true strain data obtained from hot isothermal compression tests on 9Cr-1Mo steel in a wide range of temperatures (1173-1373 K, i.e. 900-1100 {sup o}C) and strain rates (0.01-100 s{sup -1}). The constitutive equation for hot deformation is represented by a hyperbolic-sine Arrhenius type equation relating flow stress, strain rate and temperature, and could be described by the Zener-Hollomon parameter in an exponential type equation. The influence of strain was incorporated in the constitutive equation by considering the variation of material constants as a function of strain. It is observed that the compensation for strain could not accurately predict the flow stress for the entire strain rate and temperature regime. The constitutive equation was revised incorporating compensation for both strain and strain rate by suitably modifying the Zener-Hollomon parameter and the modified constitutive equation is found to give good prediction of flow stresses for most strain rate and temperature combinations. - Highlights: > Constitutive analysis is performed on hot compression flow data on 9Cr-1Mo steel. > The influence of strain was incorporated in hyperbolic-sine constitutive equation. > The material constants in constitutive equation were found to vary with strain. > Constitutive equation was revised by suitably modifying the Zener-Hollomon parameter. > The modified constitutive equation gave good prediction of the flow stress.

  1. Prediction of Air Flow and Temperature Distribution Inside a Yogurt Cooling Room Using Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    A Surendhar

    2015-01-01

    Full Text Available Air flow and heat transfer inside a yogurt cooling room were analysed using Computational Fluid Dynamics. Air flow and heat transfer models were based on 3D, unsteady state, incompressible, Reynolds-averaged Navier-Stokes equations and energy equations. Yogurt cooling room was modelled with the measured geometry using 3D design tool AutoCAD. Yogurt cooling room model was exported into the flow simulation software by specifying properties of inlet air, yogurt, pallet and walls of the room. Packing material was not considered in this study because of less thickness (cup-0.5mm, carton box-1.5mm and negligible resistance created in the conduction of heat. 3D Computational domain was meshed with hexahedral cells and governing equations were solved using explicit finite volume method. Air flow pattern inside the room and the temperature distribution in the bulk of palletized yogurt were predicted. Through validation, the variation in the temperature distribution and velocity vector from the measured value was found to be 2.0oC (maximum and 30% respectively. From the simulation and the measured value of the temperature distribution, it was observed that the temperature was non-uniform over the bulk of yogurt. This might be due to refrigeration capacity, air flow pattern, stacking of yogurt or geometry of the room. Required results were achieved by changing the location of the cooling fan.

  2. Prediction of high temperature flow stress in 9Cr-1Mo ferritic steel during hot compression

    International Nuclear Information System (INIS)

    Constitutive analysis was performed on the experimental true stress-true strain data obtained from hot isothermal compression tests on 9Cr-1Mo steel in a wide range of temperatures (1173-1373 K, i.e. 900-1100 oC) and strain rates (0.01-100 s-1). The constitutive equation for hot deformation is represented by a hyperbolic-sine Arrhenius type equation relating flow stress, strain rate and temperature, and could be described by the Zener-Hollomon parameter in an exponential type equation. The influence of strain was incorporated in the constitutive equation by considering the variation of material constants as a function of strain. It is observed that the compensation for strain could not accurately predict the flow stress for the entire strain rate and temperature regime. The constitutive equation was revised incorporating compensation for both strain and strain rate by suitably modifying the Zener-Hollomon parameter and the modified constitutive equation is found to give good prediction of flow stresses for most strain rate and temperature combinations. - Highlights: → Constitutive analysis is performed on hot compression flow data on 9Cr-1Mo steel. → The influence of strain was incorporated in hyperbolic-sine constitutive equation. → The material constants in constitutive equation were found to vary with strain. → Constitutive equation was revised by suitably modifying the Zener-Hollomon parameter. → The modified constitutive equation gave good prediction of the flow stress.

  3. Full-field velocity and temperature measurements using magnetic resonance imaging in turbulent complex internal flows

    International Nuclear Information System (INIS)

    Flow and heat transfer in complex internal passages are difficult to predict due to the presence of strong secondary flows and multiple regions of separation. Two methods based on magnetic resonance imaging called 4D magnetic resonance velocimetry (4D-MRV) and thermometry (4D-MRT) are described for measuring the full-field mean velocities and temperatures, respectively, in complex internal passage flows. 4D-MRV measurements are presented for flow through a model of a gas turbine blade internal cooling passage geometry with Reh = 10,000 and compared to PIV measurements in a highly complex 180 deg bend. Measured three-component velocities provide excellent qualitative and quantitative insight into flow structures throughout the entire flow domain. The velocities agree within ±10% in magnitude and ±10 deg in direction in a large portion of the bend which is characterized by turbulent fluctuations as high as 10-20% of the passage inlet bulk velocity. Integrated average flow rates are accurate to 4% throughout the flow domain. Preliminary 4D-MRV/MRT results are presented for heated fully developed turbulent pipe flow at ReD = 13,000

  4. Modelling of temperature in deep boreholes and evaluation of geothermal heat flow at Forsmark and Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, Jan; Back, Paer-Erik; Laendell, Maerta; Sundberg, Anders (GEO INNOVA AB, Linkoeping (Sweden))

    2009-06-15

    This report presents modelling of temperature and temperature gradients in boreholes in Laxemar and Forsmark and fitting to measured temperature data. The modelling is performed with an analytical expression including thermal conductivity, thermal diffusivity, heat flow, internal heat generation and climate events in the past. As a result of the fitting procedure it is also possible to evaluate local heat flow values for the two sites. However, since there is no independent evaluation of the heat flow, uncertainties in for example thermal conductivity, diffusivity and the palaeoclimate temperature curve are transferred into uncertainties in the heat flow. Both for Forsmark and Laxemar, reasonably good fits were achieved between models and data on borehole temperatures. However, none of the general models achieved a fit within the 95% confidence intervals of the measurements. This was achieved in some cases for the additional optimised models. Several of the model parameters are uncertain. A good model fit does not automatically imply that 'correct' values have been used for these parameters. Similar model fits can be expected with different sets of parameter values. The palaeoclimatically corrected surface mean heat flow at Forsmark and Laxemar is suggested to be 61 and 56 mW/m2 respectively. If all uncertainties are combined, including data uncertainties, the total uncertainty in the heat flow determination is judged to be within +12% to -14% for both sites. The corrections for palaeoclimate are quite large and verify the need of site-specific climate descriptions. Estimations of the current ground surface temperature have been made by extrapolations from measured temperature logging. The mean extrapolated ground surface temperature in Forsmark and Laxemar is estimated to 6.5 deg and 7.3 deg C respectively. This is approximately 1.7 deg C higher for Forsmark, and 1.6 deg C higher for Laxemar compared to data in the report SKB-TR-06-23. Comparison with

  5. Modelling of temperature in deep boreholes and evaluation of geothermal heat flow at Forsmark and Laxemar

    International Nuclear Information System (INIS)

    This report presents modelling of temperature and temperature gradients in boreholes in Laxemar and Forsmark and fitting to measured temperature data. The modelling is performed with an analytical expression including thermal conductivity, thermal diffusivity, heat flow, internal heat generation and climate events in the past. As a result of the fitting procedure it is also possible to evaluate local heat flow values for the two sites. However, since there is no independent evaluation of the heat flow, uncertainties in for example thermal conductivity, diffusivity and the palaeoclimate temperature curve are transferred into uncertainties in the heat flow. Both for Forsmark and Laxemar, reasonably good fits were achieved between models and data on borehole temperatures. However, none of the general models achieved a fit within the 95% confidence intervals of the measurements. This was achieved in some cases for the additional optimised models. Several of the model parameters are uncertain. A good model fit does not automatically imply that 'correct' values have been used for these parameters. Similar model fits can be expected with different sets of parameter values. The palaeoclimatically corrected surface mean heat flow at Forsmark and Laxemar is suggested to be 61 and 56 mW/m2 respectively. If all uncertainties are combined, including data uncertainties, the total uncertainty in the heat flow determination is judged to be within +12% to -14% for both sites. The corrections for palaeoclimate are quite large and verify the need of site-specific climate descriptions. Estimations of the current ground surface temperature have been made by extrapolations from measured temperature logging. The mean extrapolated ground surface temperature in Forsmark and Laxemar is estimated to 6.5 deg and 7.3 deg C respectively. This is approximately 1.7 deg C higher for Forsmark, and 1.6 deg C higher for Laxemar compared to data in the report SKB-TR-06-23. Comparison with air

  6. Temperature and flow fields in a high prandtl number liquid bridge under microgravity

    Directory of Open Access Journals (Sweden)

    Yang Shuo

    2015-01-01

    Full Text Available The temperature and flow fields of high prandtl number liquid bridge with surface deformation have been investigated under microgravity by a developed numerical model, and numerical simulations have been carried out based on the Navier-Stokes equations coupled with the energy conservation equation on a staggered grid. In numerical calculations, the free surface deformation and the effects of ambient air are considered. The surface deformation of liquid bridge is monitored by level set method of mass conservation to capture two phase interfaces. Simultaneously, results of temperature and flow fields in liquid bridge are given.

  7. Pressure Transducer Calibration Flow Speed, Temperature and Water Level on Reactor Protection Instrumentation System

    International Nuclear Information System (INIS)

    This experiment (on RSG-GAS) has calibrated a part of the transducers of reactor protection's measurement channels. The calibration of the transducers is a special program of the RSG-GAS maintenance program. The measurement channels transducers are the transducers of pressure measurement channel, the temperature measurement channel, the flow measurement channel and the water level measurement channel. The calibrations have used the special tools of the pressure and flow test, temperature test and water level test. These calibrations have re adjusted and re standardized all of these mentioned transducers. These work has brought the performance of the 25% of the transducers in reactor protection system back to their base

  8. Simultaneous measurements of temperature and density in air flows using UV laser spectroscopy

    Science.gov (United States)

    Fletcher, D. G.; Mckenzie, R. L.

    1991-01-01

    The simultaneous measurement of temperature and density using laser-induced fluorescence of oxygen in combination with Q-branch Raman scattering of nitrogen and oxygen is demonstrated in a low-speed air flow. The lowest density and temperature measured in the experiment correspond to the freestream values at Mach 5 in the Ames 3.5-Foot Hypersonic Wind Tunnel for stagnation conditions of 100 atm and 1000 K. The experimental results demonstrate the viability of the optical technique for measurements that support the study of compressible turbulence and the validation of numerical codes in supersonic and hypersonic wind tunnel flows.

  9. Large concentration changes due to thermal diffusion effects in gas flow microsystems with temperature gradients

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Johannessen, Tue; Jensen, Søren;

    Thermal diffusion, or Sorét diffusion, is shown to cause significant concentration changes and transients in gas flow microsystems with temperature gradients. In a silicon microsystem, a temperature gradient of about 100 oC/mm is measured to produce concentration transients of up to 13.7 % in an...... argon/helium mixture, when the flow is abruptly changed from a high value to a low value. Finite element simulations of the thermal diffusion in a geometry similar to the experimental setup reproduce the measurements....

  10. Fluid simulation of tokamak ion temperature gradient turbulence with zonal flow closure model

    Science.gov (United States)

    Yamagishi, Osamu; Sugama, Hideo

    2016-03-01

    Nonlinear fluid simulation of turbulence driven by ion temperature gradient modes in the tokamak fluxtube configuration is performed by combining two different closure models. One model is a gyrofluid model by Beer and Hammett [Phys. Plasmas 3, 4046 (1996)], and the other is a closure model to reproduce the kinetic zonal flow response [Sugama et al., Phys. Plasmas 14, 022502 (2007)]. By including the zonal flow closure, generation of zonal flows, significant reduction in energy transport, reproduction of the gyrokinetic transport level, and nonlinear upshift on the critical value of gradient scale length are observed.

  11. Study of VTOL in ground-effect flow field including temperature effect

    Science.gov (United States)

    Hill, W. G.; Jenkins, R. C.; Kalemaris, S. G.; Siclari, M. J.

    1982-01-01

    Detailed pressure, temperature, and velocity data were obtained for twin-fan configurations in-ground-effect and flow models to aid in predicting pressures and upwash forces on aircraft surfaces were developed. For the basic experiments, 49.5 mm-diameter jets were used, oriented normal to a simulated round plane, with pressurized, heated air providing a jet. The experimental data consisted of: (1) the effect of jet height and temperature on the ground, model, and upwash pressures, and temperatures, (2) the effect of simulated aircraft surfaces on the isolated flow field, (3) the jet-induced forces on a three-dimensional body with various strakes, (4) the effects of non-uniform coannular jets. For the uniform circular jets, temperature was varied from room temperature (24 C) to 232 C. Jet total pressure was varied between 9,300 Pascals and 31,500 Pascals. For the coannular jets, intended to represent turbofan engines, fan temperature was maintained at room temperature while core temperature was varied from room temperature to 437 C. Results are presented.

  12. A Study on Flow Behavior of AA5086 Over a Wide Range of Temperatures

    Science.gov (United States)

    Asgharzadeh, A.; Jamshidi Aval, H.; Serajzadeh, S.

    2016-03-01

    Flow stress behavior of AA5086 was determined using tensile testing at different temperatures from room temperature to 500 °C and strain rates varying between 0.002 and 1 s-1. The strain rate sensitivity parameter and occurrence of dynamic strain aging were then investigated in which an Arrhenius-type model was employed to study the serrated flow. Additionally, hot deformation behavior at temperatures higher than 320 °C was evaluated utilizing hyperbolic-sine constitutive equation. Finally, a feed forward artificial neural network model with back propagation learning algorithm was proposed to predict flow stress for all deformation conditions. The results demonstrated that the strain rate sensitivity at temperature range of 25-270 °C was negative due to occurrence of dynamic strain aging leading to significant reduction in fracture strain. The serrated yielding activation energy was found to be 46.1 kJ/mol. It indicated that the migration of Mg-atoms could be the main reason for this phenomenon. The hot deformation activation energy of AA5086 was also calculated about 202.3 kJ/mol while the dynamic recovery was the main softening process. Moreover, the ANN model having two hidden layers was shown to be an efficient structure for determining flow stress of the examined alloy for all temperatures and strain rates.

  13. Study on temperature and flow fluctuation phenomena in pressurizer spray pipe of PWR

    International Nuclear Information System (INIS)

    Thermal fatigue cracking may initiate in pressurizer spray pipe of PWR where oscillations of water surface may exist. In order to clarify the flow and thermal conditions in the pressurizer spray pipe, an experiment was conducted for a steam-water flow using a mock-up pressurizer spray pipe. It was shown that the fluid temperature fluctuations were not caused by the waves on the water surface, but were caused by temperature fluctuations in water layer below the interface. Visualization tests were conducted to investigate the detail mechanism of the fluctuation using the rectangular pipe made of polycarbonate resin. The clouds were observed below the steam-water interface and it seemed like an internal wave. It was shown that the maximum of the temperature fluctuations increases with increase the steam-water temperature difference and the prominent frequency of the fluctuations was nearly equal to 0.1Hz∼1Hz. (author)

  14. Direct numerical simulation of Taylor-Couette flow subjected to a radial temperature gradient

    Science.gov (United States)

    Teng, Hao; Liu, Nansheng; Lu, Xiyun; Khomami, Bamin

    2015-12-01

    Direct numerical simulations have been performed to study the Taylor-Couette (TC) flow between two rotating, coaxial cylinders in the presence of a radial temperature gradient. Specifically, the influence of the buoyant force and the outer cylinder rotation on the turbulent TC flow system with the radius ratio η = 0.912 was examined. For the co-rotating TC flows with Rei (inner cylinder) =1000 and Reo (outer cylinder) =100, a transition pathway to highly turbulent flows is realized by increasing σ, a parameter signifying the ratio of buoyant to inertial force. This nonlinear flow transition involves four intriguing states that emerge in sequence as chaotic wavy vortex flow for σ = 0, wavy interpenetrating spiral flows for σ = 0.02 and 0.05, intermittent turbulent spirals for σ = 0.1 and 0.2, and turbulent spirals for σ = 0.4. Overall, the fluid motion changes from a centrifugally driven flow regime characterized by large-scale wavy Taylor vortices (TVs) to a buoyancy-dominated flow regime characterized by small-scale turbulent vortices. Commensurate changes in turbulence statistics and heat transfer are seen as a result of the weakening of large-scale TV circulations and enhancement of turbulent motions. Additionally, the influence of variation of the outer cylinder rotation, -500 flows with a weaker influence on the fluctuating fluid motions. Of special interest, here are the turbulent dynamics near the outer wall where a marked decrease of turbulence intensity and a sign inversion of the Reynolds stress Rrz are observed for the strongly counter-rotating regimes (Reo = - 300 and -500). To this end, it has been shown that the underlying flow physics for this drastic modification are associated with the modification of the correlation between the radial and axial fluctuating motions. In turn, the intriguing effects of this modification on the mean axial flow, turbulent statistics, force balance, and dynamic processes such as turbulence production and

  15. Evaluating the Flow Processes in Ultrafine-Grained Materials at Elevated Temperatures

    OpenAIRE

    Megumi Kawasaki; Terence G. Langdon

    2013-01-01

    When polycrystalline materials are tested in tension at elevated temperatures, the flow mechanisms depend upon various parameters including the temperature of testing, the applied stress and the material grain size. The plotting of deformation mechanism maps is a procedure used widely in displaying and interpreting the creep properties of conventional coarse-grained metals but there have been few attempts to date to use this same procedure for ultrafine-grained and nanocrystalline materials p...

  16. Unsteady Flow of a Dusty Conducting Fluid Between Parallel Porous Plates With Temperature Dependent Viscosity

    OpenAIRE

    ATTIA, Hazem A.

    2005-01-01

    This paper studies unsteady laminar flow of dusty conducting fluid between parallel porous plates with temperature dependent viscosity. The fluid is acted upon by a constant pressure gradient and an external uniform magnetic field is applied perpendicular to the plates. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below. The viscosity of the fluid is assumed to vary exponentially with temperature. The governing nonlin...

  17. High temperature ultrasonic gas flow sensor based on lead free piezoelectric material

    OpenAIRE

    Krsmanovic, Dalibor

    2011-01-01

    The review of current technologies for measurement of gas velocity in stack flow applications is undertaken and it is shown that the ultrasonic time-of-flight method is the most suitable and offers a number of advantages over alternatives. Weakness of current piezoelectric based transducers are identified as the inability to operate at temperatures above 400 ?C due to limitation of piezoelectric materials used, and a case for development of an alternative high temperature material is put forw...

  18. Influence of Slip Condition on Unsteady Free Convection Flow of Viscous Fluid with Ramped Wall Temperature

    Directory of Open Access Journals (Sweden)

    Sami Ul Haq

    2015-01-01

    Full Text Available The objective of this study is to explore the influence of wall slip condition on a free convection flow of an incompressible viscous fluid with heat transfer and ramped wall temperature. Exact solution of the problem is obtained by using Laplace transform technique. Graphical results to see the effects of Prandtl number Pr, time t, and slip parameter η on velocity and skin friction for the case of ramped and constant temperature of the plate are provided and discussed.

  19. Temperature measurements in carbonatite lava lakes and flows from oldoinyo lengai, Tanzania.

    Science.gov (United States)

    Krafft, M; Keller, J

    1989-07-14

    The petrogenesis of carbonatites has important implications for mantle processes and for the magmatic evolution of mantle melts rich in carbon dioxide. Oldoinyo Lengai, Tanzania, is the only active carbonatite volcano on Earth. Its highly alkalic, sodium-rich lava, although different in composition from the more common calcium-rich carbonatites, provides the opportunity for observations of the physical characteristics of carbonatite melts. Temperature measurements on active carbonatitic lava flows and from carbonatitic lava lakes were carried out during a period of effusive activity in June 1988. Temperatures ranged from 491 degrees to 519 degrees C. The highest temperature, measured from a carbonatitic lava lake, was 544 degrees C. These temperatures are several hundred degrees lower than measurements from any silicate lava. At the observed temperatures, the carbonatite melt had lower viscosities than the most fluid basaltic lavas. The unusually low magmatic temperatures were confirmed with 1-atmosphere melting experiments on natural samples. PMID:17787875

  20. Characteristics of MSWI fly ash during vitrification

    Institute of Scientific and Technical Information of China (English)

    TIAN Shu-lei; WANG Qi; WANG Qun-hui; MA Hong-zhi

    2009-01-01

    The vitrification characteristics of municipal solid waste incinerator (MSWI) fly ash were investigated. Effects of temperature on the binding efficiency of heavy metals, the change of chemical compositions and the weight loss of fly ash in the range of 800 - 1350 ℃ were studied. Toxicity Characteristic Leaching Procedure (TCLP) of the United States was used to analyze the leaching characteristics of heavy metals in fly ash and molten slag. Results indicate that chemical compositions, the weight loss of fly ash and the binding efficiency of heavy metals in fly ash have a tremendous change in the range of 1150 - 1260 ℃. The percentage of CaO, SiO2and AI203 increases with the increasing temperature, whereas it is contrary for SO3 , K2O, Na20 and CI; especially when the temperature is 1260 ℃, the percentage of these four elements decreases sharply from 43.72%to 0. 71%. The weight loss occurs obviously in the range of 1150 - 1260 ℃. Heavy metals of Pb and Cd are almost vaporized above 1000 ℃. Cr is not volatile and its binding efficiency can reach 100% below 1000 ℃. Resuits of TCLP indicate that the heavy metal content of molten slag is beyond stipulated limit values.

  1. Preliminary Study of Fly Ash Ceramic Process

    International Nuclear Information System (INIS)

    Preliminary study of ceramic production process from two components ofwhich are fly ash and feldspar has been done. Aluminosilicate substancecontained in the fly ash is a basic material a former ceramic body, if itfired at the temperature of 1000 oC forms mullite (3Al2O3.2SiO2). Mulliteis a refractory material which is very stable at the temperature changing.This experiment studies the ceramic production process of two componentsnamely fly ash with particle size of oC.Steps of processes are making paste of fly ash and feldspar, making of greenpellets, and firing of pellets, physical analysis of ceramic including volumedecrease, lost ignition, porosity, density, water sorption, compressivestrength. The experiment result at firing temperature of 1000 oC were shownthat best composition at the weight ratio of fly ash to feldspar are 60/40and 50/50. It physical characteristic respectively are decrease of volume0.54 and 0.69 %, lost ignition = 11.98 and 11.78 %, porosity = 0.159 and0.155, density = 2.05 and 2.06 g/cm3, water sorption = 18.96 and 18.36 %,compressive strength = 24.82 and 24.79 kN/mm2. (author)

  2. Failure to phytosanitize ash firewood infested with emerald ash borer in a small dry kiln using ISPM-15 standards.

    Science.gov (United States)

    Goebel, P Charles; Bumgardner, Matthew S; Herms, Daniel A; Sabula, Andrew

    2010-06-01

    Although current USDA-APHIS standards suggest that a core temperature of 71.1 degrees C (160 degrees F) for 75 min is needed to adequately sanitize emerald ash borer, Agrilus planipennis Fairmaire-infested firewood, it is unclear whether more moderate (and economical) treatment regimes will adequately eradicate emerald ash borer larvae and prepupae from ash firewood. We constructed a small dry kiln in an effort to emulate the type of technology a small- to medium-sized firewood producer might use to examine whether treatments with lower temperature and time regimes successfully eliminate emerald ash borer from both spilt and roundwood firewood. Using white ash (Fraxinus americana L.) firewood collected from a stand with a heavy infestation of emerald ash borer in Delaware, OH, we treated the firewood using the following temperature and time regime: 46 degrees C (114.8 degrees F) for 30 min, 46 degrees C (114.8 degrees F) for 60 min, 56 degrees C (132.8 degrees F) for 30 min, and 56 degrees C (132.8 degrees F) for 60 min. Temperatures were recorded for the outer 2.54-cm (1-in.) of firewood. After treatment, all firewood was placed under mesh netting and emerald ash borer were allowed to develop and emerge under natural conditions. No treatments seemed to be successful at eliminating emerald ash borer larvae and perpupae as all treatments (including two nontreated controls) experienced some emerald ash borer emergence. However, the 56 degrees C (132.8 degrees F) treatments did result in considerably less emerald ash borer emergence than the 46 degrees C (114.8 degrees F) treatments. Further investigation is needed to determine whether longer exposure to the higher temperature (56 degrees C) will successfully sanitize emerald ash borer-infested firewood. PMID:20568603

  3. Gyrokinetic analysis of ion temperature gradient modes in the presence of sheared flows

    International Nuclear Information System (INIS)

    The linearized gyrokinetic equation governing electrostatic microinstabilities in the presence of sheared equilibrium flows in both the z and y directions has been systematically derived for a sheared slab geometry, where in the large-aspect-ratio limit z and y directions correspond to the toroidal and poloidal directions, respectively. In the familiar long perpendicular wavelength regime (kperpendicularρii) modes are found to be stabilized for bold cflx y direction flows with a velocity shear scale comparable to that of the ion temperature gradient and velocities of a few percent of the sound speed. Sheared flows in the z direction taken alone are usually destabilizing, with the effect being independent of the sign of the flow. However, when both types are simultaneously considered, it is found that in the presence of sheared bold cflx z -direction flow, sheared bold cflx y-direction flow can be either stabilizing or destabilizing depending on the relative sign of these flows. However, for sufficiently large values of v'y the mode is completely stabilized regardless of the sign of vzv'y. The importance of a proper kinetic treatment of this problem is supported by comparisons with fluid estimates. In particular, when such effects are favorable, significantly smaller values of sheared (bold cflx y)-direction flow are required for stability than fluid estimates would indicate

  4. Study of a Liquid Plug-Flow Thermal Cycling Technique Using a Temperature Gradient-Based Actuator

    Directory of Open Access Journals (Sweden)

    Yusuke Fuchiwaki

    2014-10-01

    Full Text Available Easy-to-use thermal cycling for performing rapid and small-volume DNA amplification on a single chip has attracted great interest in the area of rapid field detection of biological agents. For this purpose, as a more practical alternative to conventional continuous flow thermal cycling, liquid plug-flow thermal cycling utilizes a thermal gradient generated in a serpentine rectangular flow microchannel as an actuator. The transit time and flow speed of the plug flow varied drastically in each temperature zone due to the difference in the tension at the interface between temperature gradients. According to thermal distribution analyses in microfluidics, the plug flow allowed for a slow heating process, but a fast cooling process. The thermal cycle of the microfluid was consistent with the recommended temperature gradient for PCR. Indeed, amplification efficiency of the plug flow was superior to continuous flow PCR, and provided an impressive improvement over previously-reported flow microchannel thermal cycling techniques.

  5. Deformation microstructure and positive temperature dependence of flow stress in Ni3Ge

    International Nuclear Information System (INIS)

    Single crystalline specimens of Ni3Ge were compressed along [0 0 1] at different temperatures. Temperature dependence of the critical resolved shear stress (τ0(T)) has been obtained. Detailed measurements at cryogen temperatures (4.2-77 K temperature interval) showed that the increase of the yield stress with temperature starts at liquid helium temperature. The values of the apparent activation volume (V*) have been obtained as a result of stress relaxation tests repeated along the stress-strain curve at different stress levels at seven temperatures (77, 293, 373, 473, 573, 673, 773 K). Transmission electron microscopy (TEM) methods were used to analyze the evolution of dislocation structure with temperature and strain. The measurements of the straight dislocations fraction determined as δ = ρsd / ρ, (ρsd is the straight dislocation density, ρ is a total dislocation density) have been performed. The experimental data obtained in different tests in Ni3Ge confirm two-stage nature of the positive temperature dependence of the flow stress of alloys with the L12 structure. The model of thermal strengthening considering two different types of mechanisms, first acting at low temperatures and second at high has been proposed. Using this model the temperature dependence of the critical resolved shear stress has been approximated and the activation parameters of thermal strengthening of Ni3Ge have been obtained

  6. Deformation microstructure and positive temperature dependence of flow stress in Ni{sub 3}Ge

    Energy Technology Data Exchange (ETDEWEB)

    Solov’eva, Yulia, E-mail: j-sol@yandex.ru; Starenchenko, Vladimir, E-mail: star@tsuab.ru; Starenchenko, Svetlana, E-mail: sve-starenchenko@yandex.ru; Solov’ev, Artem, E-mail: tsk-san@mail.ru [Tomsk State University of Architecture and Building 2, Solyanaya Sq., Tomsk, 634003 (Russian Federation)

    2016-01-15

    Single crystalline specimens of Ni{sub 3}Ge were compressed along [0 0 1] at different temperatures. Temperature dependence of the critical resolved shear stress (τ{sub 0}(T)) has been obtained. Detailed measurements at cryogen temperatures (4.2-77 K temperature interval) showed that the increase of the yield stress with temperature starts at liquid helium temperature. The values of the apparent activation volume (V*) have been obtained as a result of stress relaxation tests repeated along the stress-strain curve at different stress levels at seven temperatures (77, 293, 373, 473, 573, 673, 773 K). Transmission electron microscopy (TEM) methods were used to analyze the evolution of dislocation structure with temperature and strain. The measurements of the straight dislocations fraction determined as δ = ρ{sub sd} / ρ, (ρ{sub sd} is the straight dislocation density, ρ is a total dislocation density) have been performed. The experimental data obtained in different tests in Ni{sub 3}Ge confirm two-stage nature of the positive temperature dependence of the flow stress of alloys with the L1{sub 2} structure. The model of thermal strengthening considering two different types of mechanisms, first acting at low temperatures and second at high has been proposed. Using this model the temperature dependence of the critical resolved shear stress has been approximated and the activation parameters of thermal strengthening of Ni{sub 3}Ge have been obtained.

  7. Desulfurization of flue gases by oil shale ash

    International Nuclear Information System (INIS)

    The possibility of using different ashes (furnace ash, cyclone ash) at the Estonian and Baltic Thermal Power Plants in recycle as a reagent for deeper desulfurization of flue gases and the ways of their activation (crushing, hydratation) were studied. The experiments were carried out in a derivatograph, a laboratory tube furnace and a fluidized bed kiln; different methods of analysis (chemical, X-ray, BET dynamic desorption, SEM, ion chromatography, etc.) were used. The optimum temperature interval for SO2 removal from the gas phase in the fluidized bed conditions for ashes without previous activation is 750-850 deg C and for hydrated ashes 550-850 deg C. The maximum SO2 removal efficiency up to 75% was achieved by using hydrated furnace ash, which means that the total SO2 removal efficiency increased accordingly, up to 95%. (author). 3 tabs., 5 figs., 9 refs

  8. Determination of metal foam flow conditions at a temperature higher than the liquidus temperature

    Directory of Open Access Journals (Sweden)

    J. Grabian

    2011-01-01

    Full Text Available As it is known a foam made of composite with aluminium alloy matrix and SiC particles reinforcement does not reach the liquid state evenat a temperature over 1000°C. The causes of such behaviour of foam have been examined. It has been found that it is due to two phenomena. One is connected with the creation of continuous layer of oxides at the boundary of gaseous pores and liquid metal lic phase. The other is an increase of the apparent viscosity of solids suspended in liquid metal along with an increased content of these inclusions to the point where the suspension loses its continuity.

  9. Measurement of Plasma Ion Temperature and Flow Velocity from Chord-Averaged Emission Line Profile

    Indian Academy of Sciences (India)

    Xu Wei

    2011-03-01

    The distinction between Doppler broadening and Doppler shift has been analysed, the differences between Gaussian fitting and the distribution of chord-integral line shape have also been discussed. Local ion temperature and flow velocity have been derived from the chord-averaged emission line profile by a chosen-point Gaussian fitting technique.

  10. Mineralogy and phase transition of oil sands coke ash

    Energy Technology Data Exchange (ETDEWEB)

    Heemun Jang; Thomas H. Etsell [University of Alberta, Edmonton, AB (Canada). Department of Chemical and Materials Engineering

    2006-08-15

    Coke obtained from Syncrude and Suncor was investigated to characterize the metals and minerals by ashing it at various temperatures. Samples were collected by high temperature ashing at 100{sup o}C intervals from 400 to 1200{sup o}C. Samples were also obtained from low temperature ashing (LTA) which gives little effect on the mineral assemblage compared to HTA samples. X-ray diffraction patterns of Suncor and Syncrude coke ash were analyzed qualitatively and quantitatively to characterize the mineral phases in the sample and their thermal transition behavior. In Suncor ash, kaolinite, illite, gypsum, anhydrite, microcline, anorthite, hematite, sillimanite and quartz were dominant phases in ash from the LTA temperature up to 700{sup o}C, and mullite, cristobalite, hercynite, albite, anorthite, pseudobrookite and other iron-titanium oxides were dominant mineral phases from 700 to 1200{sup o}C. In Syncrude ash, illite, anhydrite, quartz, anorthite, microcline, sillimanite and hematite were dominant up to 700{sup o}C, and hercynite, anorthite, albite, pseudobrookite and other iron-titanium oxides were dominant up to 1200{sup o}C. The higher quantities of Ca, K and Na, and the lower quantities of V, Fe and Ni in Syncrude ash resulted in higher amorphocity and the different mineral phases. 32 refs., 3 figs., 5 tabs.

  11. Influence of temperature and addition of fiber in the flow behavior of orange juice

    Directory of Open Access Journals (Sweden)

    Raúl Siche

    2012-12-01

    Full Text Available In this study the influence of the addition of orange fiber in the flow behavior of orange juice was evaluated, using for this the Herschel-Bulkley model parameters. It was observed that the flow behavior of the juices changed due to the addition of fiber, from Newtonian to Pseudoplastic when its fiber content was 5% and the temperature changed from 30 °C to 20 °C, and from Pseudoplastic to Herschel-Bulkley when its fiber content was 12.5% and the temperature changed from 10 °C to 0 °C. The increase in fiber content resulted in a progressive increase of consistency and a decrease of the flow behavior index.

  12. Determination of primary flow by correlation of temperatures of the coolant

    International Nuclear Information System (INIS)

    Correlation techniques are often used to assess primary coolant flow in nuclear reactors. Observable fluctuations of some physical or chemical coolant properties are suitable for this purpose. This work describes a development carried out at the National Atomic Energy Commission of Argentina (CNEA) to apply this technique to correlate temperature fluctuations. A laboratory test was performed. Two thermocouples were installed on a hydraulic loop. A stationary flow of water circulated by the mentioned loop, where a mechanical turbine type flowmeter was installed. Transit times given by the correlation flowmeter, for different flow values measured with the mechanical flowmeter, were registered and a calibration between them was done. A very good linear behavior was obtained in all the measured range. It was necessary to increase the fluctuation level by adding water at different temperatures at the measuring system input. (author)

  13. Multitechnique multielemental analysis of coal and fly ash

    International Nuclear Information System (INIS)

    The coal sample is first ashed with high temperature ashing or with RF plasma low temperature ashing. The coal ash or fly ash can be analyzed for major ash elements by fusing with lithium tetraborate in an automatic fusion device, the Claisse Fluxer. The ash samples are also dissolved in a Parr bomb in a mixture of aqua regia and HF. Subsequently, the solutions are analyzed for eight major (Al, Ca, Fe, K, Mg, Na, Si, and Ti) and 20 trace elements (As, B, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sr, U, V, and Zn) by inductively coupled plasma emission spectroscopy. Mercury in coal and fly ash is determined on a separate aliquot by the cold vapor atomic absorption technique. Fluorine and chlorine in the samples are determined by fusing with Na2CO3 and Eschka mixture, respectively, and then measuring the two ions in solution with specific ion electrodes. Oxygen in the samples can be determined rapidly and nondestructively by 14-MeV neutron activation analysis. These methods have been tested by analyzing several NBS coal and fly ash standards with good accuracy and reproducibility. 10 tables

  14. Experimental volcanic ash aggregation: Internal structuring of accretionary lapilli and the role of liquid bonding

    Science.gov (United States)

    Mueller, Sebastian B.; Kueppers, Ulrich; Ayris, Paul M.; Jacob, Michael; Dingwell, Donald B.

    2016-01-01

    Explosive volcanic eruptions can release vast quantities of pyroclastic material into Earth's atmosphere, including volcanic ash, particles with diameters less than two millimeters. Ash particles can cluster together to form aggregates, in some cases reaching up to several centimeters in size. Aggregation alters ash transport and settling behavior compared to un-aggregated particles, influencing ash distribution and deposit stratigraphy. Accretionary lapilli, the most commonly preserved type of aggregates within the geologic record, can exhibit complex internal stratigraphy. The processes involved in the formation and preservation of these aggregates remain poorly constrained quantitatively. In this study, we simulate the variable gas-particle flow conditions which may be encountered within eruption plumes and pyroclastic density currents via laboratory experiments using the ProCell Lab System® of Glatt Ingenieurtechnik GmbH. In this apparatus, solid particles are set into motion in a fluidized bed over a range of well-controlled boundary conditions (particle concentration, air flow rate, gas temperature, humidity, liquid composition). Experiments were conducted with soda-lime glass beads and natural volcanic ash particles under a range of experimental conditions. Both glass beads and volcanic ash exhibited the capacity for aggregation, but stable aggregates could only be produced when materials were coated with high but volcanically-relevant concentrations of NaCl. The growth and structure of aggregates was dependent on the initial granulometry, while the rate of aggregate formation increased exponentially with increasing relative humidity (12-45% RH), before overwetting promoted mud droplet formation. Notably, by use of a broad granulometry, we generated spherical, internally structured aggregates similar to some accretionary pellets found in volcanic deposits. Adaptation of a powder-technology model offers an explanation for the origin of natural accretionary

  15. Monitoring Temperature in High Enthalpy Arc-heated Plasma Flows using Tunable Diode Laser Absorption Spectroscopy

    Science.gov (United States)

    Martin, Marcel Nations; Chang, Leyen S.; Jeffries, Jay B.; Hanson, Ronald K.; Nawaz, Anuscheh; Taunk, Jaswinder S.; Driver, David M.; Raiche, George

    2013-01-01

    A tunable diode laser sensor was designed for in situ monitoring of temperature in the arc heater of the NASA Ames IHF arcjet facility (60 MW). An external cavity diode laser was used to generate light at 777.2 nm and laser absorption used to monitor the population of electronically excited oxygen atoms in an air plasma flow. Under the assumption of thermochemical equilibrium, time-resolved temperature measurements were obtained on four lines-of-sight, which enabled evaluation of the temperature uniformity in the plasma column for different arcjet operating conditions.

  16. Investigation of Nano Structural Changes by Annealing Temperature and Uniform Oxygen Flow on Ti Layers

    Directory of Open Access Journals (Sweden)

    Haleh Kangarlou

    2011-01-01

    Full Text Available Problem statement: Ti films of the same thickness, deposition angle (near normal and deposition rate were deposited on glass substrates at room temperature under UHV conditions. Approach: Different annealing temperatures 423 K, 523 K and 623 K with uniform 7 cm3 sec-1, oxygen flow, were used to produce titanium oxide layers. Results: Thin film structures were studied using AFM, XRD and spectrophotometer methods. Roughness of the films changed due to annealing process. Conclusion/Recommendations: The getting property of Ti and annealing temperature can play an important role on the structure of the films.

  17. Experimental investigation of stabilization of flowing water temperature with a water-PCM heat exchanger

    OpenAIRE

    Charvat Pavel; Stetina Josef; Pech Ondrej; Klimes Lubomir; Ostry Milan

    2014-01-01

    Experiments have been carried out in order to investigate the stabilization of water temperature with a water-PCM heat exchanger. The water-PCM heat exchanger was of a rather simple design. It was a round tube, through which the water flowed, surrounded with an annular layer of PCM. The heat exchanger was divided into one meter long segments (modules) and the water temperature was monitored at the outlet of each of the segments. A paraffin-based PCM with the melting temperature of 42 °C was u...

  18. HIS 204 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    JOHN

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   HIS 204 Week 1 DQ 1 (Ash) HIS 204 Week 1 DQ 2 (Ash) HIS 204 Week 1 Quiz (Ash) HIS 204 Week 2 DQ 1 (Ash) HIS 204 Week 2 DQ 2 (Ash) HIS 204 Week 2 Quiz (Ash) HIS 204 Week 3 Assignment Women Right, Sacrifices & Independence (Ash) HIS 204 Week 3 DQ 1 (Ash) HIS 204 Week 3 DQ 2 (Ash) HIS 204 Week 4 DQ 1 (Ash) HIS 204 Week 4 DQ 2 (Ash) HIS 204 Week 4 Quiz (Ash) HIS 204 Week 5 DQ 1 (Ash) ...

  19. Heat flow and subsurface temperature distributions in central and western New York. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, D.S.; Fromm, K.

    1984-01-01

    Initiation of a geothermal energy program in western and central New York requires knowledge of subsurface temperatures for targeting areas of potential resources. The temperature distribution in possible geothermal reservoirs, calculated from heat flow measurements and modeling techniques, shows that a large area of New York can be considered for exploitation of geothermal resources. Though the temperatures at currently accessible depths show the availability of only a low-temperature (less than 100/sup 0/C), direct-use resource, this can be considered as an alternative for the future energy needs of New York State. From analysis of bottom-hole-temperature data and direct heat flow measurements, estimates of temperatures in the Cambrian Sandstones provide the basis of the economic evaluation of the reservoir. This reservoir contains the extractable fluids needed for targeting a potential geothermal well site in the low-temperature geothermal target zone. In the northern section of the Appalachian basin, reservoir temperatures in the Cambrian are below 50/sup 0/C but may be over 80/sup 0/C in the deeper parts of the basin in southern New York State. Using a minimum of 50/sup 0/C as a useful reservoir temperature, temperatures in excess of this value are encountered in the Theresa Formation at depths in excess of 1300 meters. Considering a maximum depth for economical drilling to be 2500 meters with present technology, the 2500 meters to the Theresa (sea level datum) forms the lower limit of the geothermal resource. Temperatures in the range of 70/sup 0/C to 80/sup 0/C are predicted for the southern portion of New York State.

  20. Parallel flow asymmetries due to non-uniform temperatures investigated by tracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zitny, R.; Thyn, J. [Czech Technical University, Dept. of Process Engineering, Prague (Czech Republic)

    2001-07-01

    The effect of flow asymmetry was observed experimentally in lateral parallel channels of continuous direct ohmic heater. While the flow in parallel channels is uniform at isothermal conditions, one stream may be delayed and even stopped or reversed if the temperature differences between channels are too high in case of heating. The effect can be explained by buoyancy and theoretical analysis predicts existence of two solutions, symmetric and asymmetric distribution of flowrates, which can be stable within a certain range of temperatures and flowrates. Integral model, based upon momentum and heat balances has been suggested with the aim to predict influence of heater geometry, fluid properties and operational parameters (flowrates, intensity of heating) upon the RTD of parallel laminar flows. The model takes into consideration also the cross-flow between the main parallel streams. This 'zonal' model enables to calculate residence time distribution (RTD) of the heater and results predict that the effects of asymmetries upon RTD is significant. Therefore the measurement of RTD characteristics seems to be promising method for detection of the parallel flow asymmetries. Experimental verification was based upon a) flow visualisation (injection of a coloured tracer and monitoring the tracer by Canon MV-100 camera), b) measurement of temperature profiles (11 thermometers Pt100), and on c) stimulus response experiments using KCl as a tracer for conductivity methods (2 Pt conductivity probes) and {sup 99}Tc as a radioisotope tracer (collimated scintillation detectors). Results confirm predicted influence of operational parameters and geometry (diameter of channels) on the stability of flow. (authors)

  1. Prediction of flow stress of 7017 aluminium alloy under high strain rate compression at elevated temperatures

    Directory of Open Access Journals (Sweden)

    Ravindranadh Bobbili

    2015-03-01

    Full Text Available An artificial neural network (ANN constitutive model and Johnson–Cook (J–C model were developed for 7017 aluminium alloy based on high strain rate data generated from split Hopkinson pressure bar (SHPB experiments at various temperatures. A neural network configuration consists of both training and validation, which is effectively employed to predict flow stress. Temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on Johnson–Cook (J–C model and neural network model was performed. It was observed that the developed neural network model could predict flow stress under various strain rates and temperatures. The experimental stress–strain data obtained from high strain rate compression tests using SHPB over a range of temperatures (25°–300 °C, strains (0.05–0.3 and strain rates (1500–4500 s−1 were employed to formulate J–C model to predict the flow stress behaviour of 7017 aluminium alloy under high strain rate loading. The J–C model and the back-propagation ANN model were developed to predict the flow stress of 7017 aluminium alloy under high strain rates, and their predictability was evaluated in terms of correlation coefficient (R and average absolute relative error (AARE. R and AARE for the J-C model are found to be 0.8461 and 10.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. The predictions of ANN model are observed to be in consistent with the experimental data for all strain rates and temperatures.

  2. Stagnation temperature in a cold hypersonic flow produced by a light free piston compression facility

    Science.gov (United States)

    Widodo, Agung; Buttsworth, David

    2013-04-01

    Stagnation temperatures at the nozzle exit of the University of Southern Queensland hypersonic wind tunnel facility have been identified using an aspirating tube device with a 0.075 mm diameter k-type butt-welded thermocouple junction positioned at its inlet. Because of the finite thermal inertia of the thermocouple, a response time correction is introduced, and uncertainties in the response time correction are assessed and minimized by operating the aspirating device over a range of different initial temperatures. Pressure measurements within the barrel of the wind tunnel facility were used to estimate a theoretical upper bound on the flow stagnation temperature by assuming isentropic compression of the test gas. Results demonstrate that for the current operating conditions, the gas which is first delivered into the hypersonic nozzle has a stagnation temperature almost identical to the isentropic compression value of around 560 K, but a cooling effect is registered for the duration of the test flow which is about 200 ms. Thermodynamic simulations based on an unsteady energy balance model with turbulent heat transfer from the test gas within the barrel demonstrate a cooling effect of a similar magnitude to that indicated by the measured temperature variation, suggesting that strong mixing of the test gas occurs within the barrel during flow discharge through the hypersonic nozzle.

  3. Regulation of electron temperature gradient turbulence by zonal flows driven by trapped electron modes

    Energy Technology Data Exchange (ETDEWEB)

    Asahi, Y., E-mail: y.asahi@nr.titech.ac.jp; Tsutsui, H.; Tsuji-Iio, S. [Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Ishizawa, A.; Watanabe, T.-H. [National Institute for Fusion Science, Gifu 509-5292 (Japan)

    2014-05-15

    Turbulent transport caused by electron temperature gradient (ETG) modes was investigated by means of gyrokinetic simulations. It was found that the ETG turbulence can be regulated by meso-scale zonal flows driven by trapped electron modes (TEMs), which are excited with much smaller growth rates than those of ETG modes. The zonal flows of which radial wavelengths are in between the ion and the electron banana widths are not shielded by trapped ions nor electrons, and hence they are effectively driven by the TEMs. It was also shown that an E × B shearing rate of the TEM-driven zonal flows is larger than or comparable to the growth rates of long-wavelength ETG modes and TEMs, which make a main contribution to the turbulent transport before excitation of the zonal flows.

  4. Studying the melting behavior of coal, biomass, and coal/biomass ash using viscosity and heated stage XRD data

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Folkedahl, B.; Dam-Johansen, Kim;

    2006-01-01

    high-temperature rotational viscometer and a hot stage XRD. The produced data were used to calculate the operating temperature of a pilot-scale entrained flow reactor during the cocombustion of biomass/ coal samples in order to ensure the slag flow and to avoid corrosion of the walls due to liquid slag......The use of biomass for power generation can result in significant economical and environmental benefits. The greenhouse emissions can be reduced as well as the cost of the produced electricity. However, ash-related problems, including slagging, agglomeration, and corrosion, can cause frequent...... unscheduled shutdowns, decreasing the availability and increasing the cost of the produced power. In addition, the fouling of the heat exchange surfaces reduces the system efficiency. In this work the melting and rheological properties of various biomass and biomass/ coal ash samples were studied by using a...

  5. Modeling of temperature field and fluid flow in hybrid welding process

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2009-07-01

    Full Text Available Mathematical and numerical model of the temperature field and the velocity field in melted zone concerning the hybrid laser – arc process was presented in this paper. The temperature field was determined by solution the transient heat transfer equation with activity of inner heat sources. Fluid flow in welding pool was determined by solution of the Navier – Stokes equation in Chorin’s projection. The fuzzy solidification front was assumed in a numerical algorithm with linear approximation of the solid phase in mushy zone. Fluid flow through porous medium was considered in mushy zone according to Darcy’s model. In the base of elaborated models and realized algorithms, results of computer simulations were presented in this study. Temperature distribution in the weld and velocity distribution in melted zone as well as welding pool shape and heat affected zone were illustrated.

  6. Reducibility of ceria-lanthana mixed oxides under temperature programmed hydrogen and inert gas flow conditions

    International Nuclear Information System (INIS)

    The present paper deals with the preparation and characterization of La/Ce mixed oxides, with La molar contents of 20, 36 and 57%. We carry out the study of the structural, textural and redox properties of the mixed oxides, comparing our results with those for pure ceria. For this aim we use temperature programmed reduction (TPR), temperature programmed desorption (TPD), nitrogen physisorption at 77 K, X-ray diffraction and high resolution electron microscopy. The mixed oxides are more easy to reduce in a flow of hydrogen than ceria. Moreover, in an inert gas flow they release oxygen in higher amounts and at lower temperatures than pure CeO2. The textural stability of the mixed oxides is also improved by incorporation of lanthana. All these properties make the ceria-lanthana mixed oxides interesting alternative candidates to substitute ceria in three-way catalyst formulations. (orig.)

  7. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

    International Nuclear Information System (INIS)

    Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.

  8. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Richard Schultz

    2012-04-01

    Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.

  9. Cold Temperature Effects on Long-Term Nitrogen Transformation Pathway in a Tidal Flow Constructed Wetland.

    Science.gov (United States)

    Pang, Yunmeng; Zhang, Yan; Yan, Xingjun; Ji, Guodong

    2015-11-17

    The present study investigated long-term treatment performance and nitrogen transformation mechanisms in tidal flow constructed wetlands (TFCWs) under 4, 8, and 12 °C temperature regimes. High and stable ammonium (NH4(+)-N) removal efficiency (93-96%) was achieved in our TFCWs, whereas nitrate (NO3(-)-N) was accumulated at different levels under different temperatures. Quantitative response relationships showed anammox/amoA, (narG+napA)/amoA, and (narG+napA)/bacteria were the respective key functional gene groups determining 4, 8, and 12 °C NO3(-)-N reduction. Pathway analysis revealed the contribution of these functional gene groups along a depth gradient. In addition, denitrification process increased, while anammox process decreased consistent with a rise in temperature from 4 to 12 °C. Furthermore, cold temperatures exhibited different effects on anammox and denitrification and their long-term acclimatization capacities changed with temperature. PMID:26460580

  10. High Temperature Flow Response Modeling of Ultra-Fine Grained Titanium

    Directory of Open Access Journals (Sweden)

    Seyed Vahid Sajadifar

    2015-07-01

    Full Text Available This work presents the mechanical behavior modeling of commercial purity titanium subjected to severe plastic deformation (SPD during post-SPD compression, at temperatures of 600-900 °C and at strain rates of 0.001-0.1 s−1. The flow response of the ultra-fine grained microstructure is modeled using the modified Johnson-Cook model as a predictive tool, aiding high temperature forming applications. It was seen that the model was satisfactory at all deformation conditions except for the deformation temperature of 600 °C. In order to improve the predictive capability, the model was extended with a corrective term for predictions at temperatures below 700 °C. The accuracy of the model was displayed with reasonable agreement, resulting in error levels of less than 5% at all deformation temperatures.

  11. Effect of Body Temperature on the Radionuclide Evaluation of Cerebral Blood Flow

    International Nuclear Information System (INIS)

    Changes in regional cerebral blood flow (rCBF) may reflect physiological correlates of the disease state. In neuro-imaging studies, some diseases have frequently been reported to be associated with reduced or increased rCBF. In a previous study we had shown evidence of heat induced vasoconstriction of the carotid artery, which is the main vessel supplying blood to the brain. This vasoconstriction may lead to a decrease in cerebral blood flow in hyperthermic patients. Most radionuclide studies used to assess cerebral blood flow are routinely performed without taking into consideration patients' body temperature. In this regard it may be noted that results of radionuclide cerebral perfusion studies may be affected by hyperthermia, which could lead to false positive studies or misinterpretation of results when they are performed on patients suffering from various cerebrovascular diseases. The objective of the present study was to investigate the importance of body temperature and its effect on the results of radionuclide cerebral perfusion studies. Cerebral blood flow was assessed using Tc-99m hexamethylpropyleneamineoxime (Tc-99m HMPAO) imaging. Baseline scintigraphic images of the brain were obtained in 10 rabbits using a gamma camera equipped with a low energy parallel hole and high resolution collimator interfaced with a computer. Repeat brain studies were performed on the same rabbits at 3 and 6 days after raising the body temperature by 2 deg. C and 4 deg. C respectively using the same imaging protocol. The counts per pixel were determined on control and hyperthermia images. The uptake of Tc-99m HMPAO in the brain was found to be significantly reduced following hyperthermia implying reduction in blood flow. This decrease in cerebral perfusion appears to be variable from region to region, being more in the cerebral hemispheres, frontal areas (olfactory lobes) than in the cerebellum. Based on the results, the authors conclude that a rise in body temperature might

  12. Washing of granulated solidification fly ash containing radioactive contaminants

    International Nuclear Information System (INIS)

    Incineration fly ash produced from city garbage, water-and-sewage sludge, and wastes generated by radioactive decontamination activities tends to have a high concentration of radioactive materials, and radioactive cesium in fly ash has high solubility in water. In order to advance the safe processing of incineration fly ash, it is necessary to have a technology for reducing the cesium in the fly ash. Washing the fly ash with water is an effective way of reducing the amount of radioactive cesium. Then, this study developed a new method for washing fly ash after granulated solidification. Laboratory tests showed that 70% or more of the radioactive cesium was removed by washing of the granulated solidification fly ash adjusted into 1-9.5 mm diameter particles under the following conditions: flow rate (SV) ≦ 10h-1 and flow volume ≧ 10 times of fly ash volume. Demonstration tests also confirmed the effectiveness of washing and the reduction of the volume of radioactive wastes. (author)

  13. Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S.; Tsang, Y.; Finsterle, S.

    2009-01-15

    A simple conceptual model has been recently developed for analyzing pressure and temperature data from flowing fluid temperature logging (FFTL) in unsaturated fractured rock. Using this conceptual model, we developed an analytical solution for FFTL pressure response, and a semianalytical solution for FFTL temperature response. We also proposed a method for estimating fracture permeability from FFTL temperature data. The conceptual model was based on some simplifying assumptions, particularly that a single-phase airflow model was used. In this paper, we develop a more comprehensive numerical model of multiphase flow and heat transfer associated with FFTL. Using this numerical model, we perform a number of forward simulations to determine the parameters that have the strongest influence on the pressure and temperature response from FFTL. We then use the iTOUGH2 optimization code to estimate these most sensitive parameters through inverse modeling and to quantify the uncertainties associated with these estimated parameters. We conclude that FFTL can be utilized to determine permeability, porosity, and thermal conductivity of the fracture rock. Two other parameters, which are not properties of the fractured rock, have strong influence on FFTL response. These are pressure and temperature in the borehole that were at equilibrium with the fractured rock formation at the beginning of FFTL. We illustrate how these parameters can also be estimated from FFTL data.

  14. Mössbauer characterization of feed coal, ash and fly ash from a thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Caballero, F.; Martínez Ovalle, S. A., E-mail: s.agustin.martinez@uptc.edu.co; Moreno Gutiérrez, M. [Universidad Pedagógica y Tecnológica de Colombia, UPTC, Grupo de Física Nuclear Aplicada y Simulación (Colombia)

    2015-06-15

    The aim of this work was apply {sup 57}Fe Transmission Mössbauer Spectroscopy at room temperature in order to study the occurrence of iron-containing mineral phases in: 1) feed coal; 2) coal ash, obtained in different stages of the ASTM D3174 standard method; and 3) fly ash, produced when coal is burned in the TERMOPAIPA IV thermal power plant localized in Boyacá, Colombia. According to obtained results, we can conclude the occurrence of pyrite and jarosite in the feed coal; Fe{sup 2+} and Fe{sup 3+} crystalline paramagnetic phases, superparamagnetic hematite and hematite in coal ash; Fe{sup 2+} and Fe{sup 3+} noncrystalline and crystalline phases, magnetite and hematite in fly ash. Precisely, for a basic understanding, this work discusses some the possible transformations that take place during coal combustion.

  15. Mössbauer characterization of feed coal, ash and fly ash from a thermal power plant

    International Nuclear Information System (INIS)

    The aim of this work was apply 57Fe Transmission Mössbauer Spectroscopy at room temperature in order to study the occurrence of iron-containing mineral phases in: 1) feed coal; 2) coal ash, obtained in different stages of the ASTM D3174 standard method; and 3) fly ash, produced when coal is burned in the TERMOPAIPA IV thermal power plant localized in Boyacá, Colombia. According to obtained results, we can conclude the occurrence of pyrite and jarosite in the feed coal; Fe2+ and Fe3+ crystalline paramagnetic phases, superparamagnetic hematite and hematite in coal ash; Fe2+ and Fe3+ noncrystalline and crystalline phases, magnetite and hematite in fly ash. Precisely, for a basic understanding, this work discusses some the possible transformations that take place during coal combustion

  16. Coal Ash Corrosion Resistant Materials Testing

    Energy Technology Data Exchange (ETDEWEB)

    D. K. McDonald; P. L. Daniel; D. J. DeVault

    2007-12-31

    In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a moderate alkali content (0.2% sodium equivalents), thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that aggressive alkali sulfate constituents were present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. Test Section A was removed in November 2001 after about 24 months of service at the desired steam temperature set point, with about 15.5 months of exposure at full temperature. A progress report, issued in October 2002, was written to document the performance of the candidate alloys in that test section. The evaluation described the condition of each tube sample after exposure. It involved a determination of the rate of wall thickness loss for these samples. In cases where there was more than one sample of a candidate material in the test section, an assessment was made of the performance of the alloy as a function of temperature. Test Sections B and C were examined during the November 2001 outage, and it was decided that

  17. Technique to Measure the Coronal Electron Temperature and Radial Flow Speed

    Science.gov (United States)

    Reginald, N. L.; Davila, J. M.; St Cyr, O. C.

    2011-12-01

    During the March 2006 total solar eclipse we conducted an imaging experiment using the Imaging Spectrograph of Coronal Electrons (ISCORE) to determine the coronal electron temperature and its radial flow speed in the low solar corona. This technique required taking images of the solar eclipse through four broadband filters centered at 385.0, 398.7, 410.0 and 423.3 nm. The K-coronal temperature is determined from intensity ratios from the 385.0 and 410.0 nm filters, and the K-coronal radial flow speed is determined from intensity ratios from the 398.7 and 423.3 nm filters. The theoretical model for this technique assumes a symmetric corona devoid of any features like streamers that might alter the coronal symmetry. The model also requires an isothermal temperature and a uniform outflow speed all along the line of sight. We will call this the Constant Parameter Thomson Scattering Model (CPTSM). The latter assumption may sound unreasonable but in the symmetric corona with rapid fall of the electron density with height in the solar corona, the major contributions to the K-coronal intensity along a given line of sight comes from the plasma properties in the vicinity of the plane of the sky. But the pressing question is how is the derived plasma properties by ISCORE compare with the nature of the true corona. For this we turn to the CORHEL model by Predictive Science Inc. which used magnetogram data to create a realistic model of the solar corona that are made available through the Community Coordinated Modeling Center (CCMC) at GSFC. That team has consistently produced the expected coronal image days prior to many total eclipses where the major coronal features from their model matched actual coronal image on the day of the eclipse. Using the CORHEL model data we have calculated the K-coronal intensities at 385.0, 398.7, 410.0 and 423.3 nm using the electron density, plasma temperature (assumed to be electron temperature) and the flow speeds of the plasma along the line

  18. BEHAVIOR OF FLOW STRESS OF ALUMINUM SHEETS USED FOR PRESSURE CAN DURING COMPRESSION AT ELEVATED TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    G.S. Fu; W.Z. Chen; K.W. Qian

    2005-01-01

    The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression testusing Gleeble1500 dynamic hot-simulation testing machine. The results show that the A1 sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the Al pieces prepared by no or conventional melt-treatment, hot deformation activation energy of Al sheets prepared by high-efficient melt-treatment is the smallest (Q = 168.0kJ/mol), which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.

  19. Determination of temperature and transverse flow velocity at chemical freeze-out in relativistic nuclear interactions

    International Nuclear Information System (INIS)

    We propose a parameter-free method to determine the temperature of a thermalized state in relativistic nuclear interactions, using the experimental μq/T and μs/T values, obtained from strange particle ratios. The hadron gas formalism and strangeness neutrality are employed to relate the quark-chemical potential μq and μs to the temperature and thus determine its value at chemical freeze-out. This temperature, together with the inverse slope parameter from mT distributions, enable the determination of the transverse flow velocity of the fireball matter, thus disentangling the thermal and flow effects. We study several nucleus-nucleus interactions from AGS and SPS and obtain the temperature, transverse flow velocity, and quark-chemical potentials. Extrapolating the systematics we predict the values of these quantities for ongoing and future experiments at AGS, SPS, and RHIC. We discuss the possibility of reaching the conditions for quark deconfinement and QGP formation and give distinct and identifiable signature. copyright 1996 The American Physical Society

  20. Prediction of FV520B Steel Flow Stresses at High Temperature and Strain Rates

    Science.gov (United States)

    Han, Xiaolan; Zhao, Shengdun; Zhang, Chenyang; Fan, Shuqin; Xu, Fan

    2015-10-01

    In order to develop reliable constitutive equations for the simulation, the hot deformation behavior of FV520B steel was investigated through isothermal compression tests in a wide range of temperatures from 900 °C to 1100 °C at an interval of 50 °C and strain rate from 0.01 to 10 s-1 on Gleeble-1500D simulator. The effects of temperature and strain rate on deformation behavior were represented by Zener-Holloman parameter in an exponent-type equation of Arrhenius constitutive. The influence of strain was incorporated in the constitutive analysis by material constants expressed as a polynomial function of strain. The constitutive equation (considering the compensation of strain) could precisely predict the flow stress only at strain rate 0.01 s-1 except at the temperatures of 900 °C and 1000 °C, whereas the flow stress predicted by a modified equation (incorporating both the strain and strain rate) demonstrated a well agreement with the experimental data throughout the entire range of temperatures and strain rates. Correlation coefficient (R) of 0.988 and average absolute relative error (AARE) of 5.7% verified the validity of developed equation from statistical analysis, which further confirmed that the modified constitutive equation could accurately predict the flow stress of FV520B steel.

  1. Room Temperature, Hybrid Sodium-Based Flow Batteries with Multi-Electron Transfer Redox Reactions

    OpenAIRE

    Shamie, Jack S.; Caihong Liu; Shaw, Leon L.; Vincent L. Sprenkle

    2015-01-01

    We introduce a new concept of hybrid Na-based flow batteries (HNFBs) with a molten Na alloy anode in conjunction with a flowing catholyte separated by a solid Na-ion exchange membrane for grid-scale energy storage. Such HNFBs can operate at ambient temperature, allow catholytes to have multiple electron transfer redox reactions per active ion, offer wide selection of catholyte chemistries with multiple active ions to couple with the highly negative Na alloy anode, and enable the use of both a...

  2. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    OpenAIRE

    Pavel Neuberger; Radomír Adamovský; Michaela Šeďová

    2014-01-01

    Temperature changes and heat flows in soils that host “slinky†-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by ...

  3. Leaching of nutrient salts from fly ash from biomass combustion

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Vu, Duc Thuong; Stenby, Mette;

    2005-01-01

    Methods to selectively leach nutrient salts from fly ash, while leaving cadmium un-dissolved were studied. Temperature, pH, water to fly ash ratio are all expected to influence the kinetics and the equilibrium boundaries for this process. Three different leaching methods were investigated. The...... moving bed process with agitation/centrifugation. It was found that a satisfactory leaching of the nutrient salts could be achieved with the third method using only two or three stages, depending on the water to fly ash ratio. It is an advantage to perform the process at temperatures above 50°C as the...... first method was a counter current moving bed process in four stages. The ash was kept in filter bags and leached with water that was introduced into the bags at 40-50°C. In the second method, fly ash and water was brought into contact in a partially fluidized bed. The third method was a counter current...

  4. Ash Deposition Trials at Three Power Stations in Denmark

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming; Larsen, Ole Hede

    1998-01-01

    Six full-scale trials were conducted at three power stations in Denmark: Ensted, Funen, and Vendsyssel power stations. During these trials, pulverized coal, bottom ash, fly ash, and deposits from cooled probes were sampled and analyzed with various techniques. On the basis of SEM analyses, the...... deposits can be grouped into five textural types, which all possess distinct textural and chemical characteristics. Likewise, the deposition mechanisms for these five types are characteristic and they may be used for constructing a model for the buildup and maturation of an ash deposit. The deposits...... collected on the probes were thin (maximum 2 mm after 9 h) and the influence of operational parameters and probe temperatures on the magnitude of the deposits were minor. The probe temperatures had no influence on the composition of the ash deposits for coals with low ash deposition propensities, whereas...

  5. Effect of span length and temperature on the 3-D confined flow around a vortex promoter

    Energy Technology Data Exchange (ETDEWEB)

    Martin, E. [Fluid Mechanics Area, School of Industrial Engineering, Universidad de Vigo, Campus Lagoas-Marcosende, 36310 Vigo (Spain); Velazquez, A., E-mail: angel.velazquez@upm.es [Aerospace Propulsion and Fluid Mechanics Department, School of Aeronautics, Universidad Politecnica de Madrid, Plaza del Cardenal Cisneros 3, 28040 Madrid (Spain)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The article deals with study of vortex promoter flow in a 3-D micro-channel. Black-Right-Pointing-Pointer Aspects studied are: channel aspect ratio and prism surface temperature. Black-Right-Pointing-Pointer Flow is classified into three different regimes depending on different parameters. Black-Right-Pointing-Pointer Results could be used for practical engineering design purposes. - Abstract: This article presents a numerical study on the influence of span length and wall temperature on the 3-D flow pattern around a square section vortex promoter located inside a micro-channel in the low Reynolds number regime. The first objective of the work is to quantify the critical Reynolds number that defines the onset of vortex shedding and to identify the different regimes that appear as a function of the channel aspect ratio (span to height ratio). We found that the critical Reynolds number for the onset of the Karman street regime increases as the aspect ratio decreases. In particular, for the aspect ratio of 1/2 the critical Reynolds number is nearly six times the critical Reynolds number of the 2-D problem. An intermediate oscillating regime between the steady and the Karman street solutions was also found to exist within a rather wide range of Reynolds numbers for small channel aspect ratios. The second objective was to investigate the influence of the vortex promoter wall temperature on both vortex shedding and flow pattern. This has practical engineering implications because the working fluid considered in the article is water that has a viscosity that depends significantly on temperature and promotes a strong coupling between the momentum and energy equations that influences the system behaviour. Results indicate that high surface temperature on the prism promotes the onset of the Karman street, suggesting design guidelines for micro-channel based heat sinks that make use of vortex promoters.

  6. Effect of span length and temperature on the 3-D confined flow around a vortex promoter

    International Nuclear Information System (INIS)

    Highlights: ► The article deals with study of vortex promoter flow in a 3-D micro-channel. ► Aspects studied are: channel aspect ratio and prism surface temperature. ► Flow is classified into three different regimes depending on different parameters. ► Results could be used for practical engineering design purposes. - Abstract: This article presents a numerical study on the influence of span length and wall temperature on the 3-D flow pattern around a square section vortex promoter located inside a micro-channel in the low Reynolds number regime. The first objective of the work is to quantify the critical Reynolds number that defines the onset of vortex shedding and to identify the different regimes that appear as a function of the channel aspect ratio (span to height ratio). We found that the critical Reynolds number for the onset of the Karman street regime increases as the aspect ratio decreases. In particular, for the aspect ratio of 1/2 the critical Reynolds number is nearly six times the critical Reynolds number of the 2-D problem. An intermediate oscillating regime between the steady and the Karman street solutions was also found to exist within a rather wide range of Reynolds numbers for small channel aspect ratios. The second objective was to investigate the influence of the vortex promoter wall temperature on both vortex shedding and flow pattern. This has practical engineering implications because the working fluid considered in the article is water that has a viscosity that depends significantly on temperature and promotes a strong coupling between the momentum and energy equations that influences the system behaviour. Results indicate that high surface temperature on the prism promotes the onset of the Karman street, suggesting design guidelines for micro-channel based heat sinks that make use of vortex promoters.

  7. Ash transformation and deposition behavior during co-firing biomass with sewage sludge

    DEFF Research Database (Denmark)

    Wang, Liang; Wu, Hao; Jensen, Peter Arendt;

    In the present work, the ash transformation and deposition behavior during wheat straw and wood waste combustion were investigated by combustion experiments in an entrained flow reactor. The influence of sewage sludge addition on ash chemistry and deposition tendency was also studied. During......-Ca-silicates. The deposits formed on a well-controlled sampling probe are dominated by molten particles rich in K silicates. Over 70% of K in the fly ash is water soluble. The fine fly ash from wood waste combustion consists of mainly KCl and NaCl. Both ash clusters and molten spherical particles are found from the...... ash deposits, which mainly contain K-silicates, K-Al-silicates and K-Ca-silicates. The sewage sludge addition significantly reduced the water soluble K and Na in the fly ash from wheat straw and wood waste combustion. Compared to pure wheat straw and wood waste, the ash deposition rates were increased...

  8. Sulphation characteristics of paper sludge ash

    Energy Technology Data Exchange (ETDEWEB)

    Roh, S.A. [Environmental Systems Research Center, Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of); Kim, S.D. [Environmental Systems Research Center, Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Dept. of Chemical and Biomolecular Engineering

    2007-04-15

    Landfills are no longer a viable solution for the disposal of sludge produced from waste water treatment plants because of the decrease in available space, rising fees and growing environmental concerns. However, thermal utilization of this waste may be an economic and sustainable disposal solution. Co-combustion of low heating value sludge with fossil fuels has a positive effect for sulfur dioxide (SO{sub 2}) emissions due to the low sulphur content of biomass fuels and increased sulphur retention in the ash. The sulphur retention is attributed to the formation of sulphates, such as CaSO{sub 4}, K{sub 2}SO{sub 4} and Na{sub 2}SO{sub 4}. The amount of fuel-ash-related sulphur sorption increases during co-combustion. Therefore, sorbents for sulphur reduction may not be required if proper control of the biomass feed is maintained. This paper presented a study in which the sulphation characteristics of calcium-rich paper sludge ash were determined for the use of co-combustion of biomass and coal. The calcium in the paper sludge ash came from the limestone filler used in the manufacturing process to increase the density and whiteness of the paper at 2 paper mills in Korea. A thermobalance reactor along with XRD and SEM-EDX were used for the analysis of sulphated ash to determine the effects of sulphation temperature, particle size and SO{sub 2} concentration on sulphation conversion. The activation energy and pre-exponential factor of sulphation reaction of sludge ash were determined based on the uniform-reaction model. X-ray diffraction analysis revealed that most of the sulphation compounds were CaSO{sub 4}. The sulphation occurred uniformly throughout the ash and the CaSO{sub 4} did not block the outer pore of the sludge ash. The uniform distributions of CaO and other inert minerals in the ash resulted in uniform sulphation with good penetration of SO{sub 2} into pores of the sludge ash without pore blocking during sulphation of CaO. 13 refs., 1 tab., 9 figs.

  9. Phosphorus recovery from sewage sludge char ash

    NARCIS (Netherlands)

    Atienza-Martinez, M.; Gea, G.; Arauzo, J.; Kersten, S.R.A.; Kootstra, A.M.J.

    2014-01-01

    Phosphorus was recovered from the ash obtained after combustion at different temperatures (600 °C, 750 °C and 900 °C) and after gasification (at 820 °C using a mixture of air and steam as fluidising agent) of char from sewage sludge fast pyrolysis carried out at 530 °C. Depending on the leaching con

  10. Safety aspects of forced flow cooldown transients in Modular High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    During some of the design basis accidents in Modular High Temperature Gas Cooled Reactors (MHTGRs), the main Heat Transport System (HTS) and the Shutdown Cooling System n removed by the passive Reactor (SCS) are assumed to have failed. Decay heat is the Cavity Cooling System (RCCS) only. If either forced flow cooling system becomes available during such a transient, its restart could significantly reduce the down-time. This report used the THATCH code to examine whether such restart, during a period of elevated core temperatures, can be accomplished within safe limits for fuel and metal component temperatures. If the reactor is scrammed, either system can apparently be restarted at any time, without exceeding any safe limits. However, under unscrammed conditions a restart of forced cooling can lead to recriticality, with fuel and metal temperatures significantly exceeding the safety limits

  11. Safety aspects of forced flow cooldown transients in modular high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, P.G.

    1992-01-01

    During some of the design basis accidents in Modular High Temperature Gas Cooled Reactors (MHTGRs) the main Heat Transport System (HTS) and the Shutdown Cooling System (SCS), are assumed to have failed. Decay heat is then removed by the passive Reactor Cavity Cooling System (RCCS) only. If either forced flow cooling system becomes available during such a transient, its restart could significantly reduce the down-time. This paper uses the THATCH code to examine whether such restart, during a period of elevated core temperatures, can be accomplished within safe limits for fuel and metal component temperatures. If the reactor is scrammed, either system can apparently be restarted at any time, without exceeding any safe limits. However, under unscrammed conditions a restart of forced cooling can lead to recriticality, with fuel and metal temperatures significantly exceeding the safety limits.

  12. Safety aspects of forced flow cooldown transients in modular high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, P.G.

    1992-09-01

    During some of the design basis accidents in Modular High Temperature Gas Cooled Reactors (MHTGRs) the main Heat Transport System (HTS) and the Shutdown Cooling System (SCS), are assumed to have failed. Decay heat is then removed by the passive Reactor Cavity Cooling System (RCCS) only. If either forced flow cooling system becomes available during such a transient, its restart could significantly reduce the down-time. This paper uses the THATCH code to examine whether such restart, during a period of elevated core temperatures, can be accomplished within safe limits for fuel and metal component temperatures. If the reactor is scrammed, either system can apparently be restarted at any time, without exceeding any safe limits. However, under unscrammed conditions a restart of forced cooling can lead to recriticality, with fuel and metal temperatures significantly exceeding the safety limits.

  13. The Mineral Transformation of Huainan Coal Ashes in Reducing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    LI Han-xu; Yoshihiko Ninomiya; DONG Zhong-bing; ZHANG Ming-xu

    2006-01-01

    By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope (CCSEM),X-ray diffraction (XRD) and X-ray fluorescence (XRF), the ash composition and the mineral components of six typical Huainan coals of different origins were studied. The transformation of mineral matter at high temperatures was tracked by XRD in reducing conditions. The quartz phase decreased sharply and the anorthite content tended to increase at first and then decreased with increasing temperatures. The formed mullite phase reached a maximum at 1250 ℃ but showed a tendency of slow decline when the temperature was over 1250 ℃. The mullite formed in the heating process was the main reason of the high ash melting temperature of Huainan coals. Differences in peak intensity of mullite and anorthite reflected differences in phase concentration of the quenched slag fractions, which contributed to the differences in ash melting temperatures. The differences in the location of an amorphous hump maximum indicated differences of glass types which may affect ash melting temperatures. For Huainan coal samples with relatively high ash melting temperatures, the intensity of the diffraction lines for mullite under reducing condition is high while for the samples with relatively low ash melting temperature the intensity for anorthite is high.

  14. Ash particle erosion on steam boiler convective section

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, V.

    1997-12-31

    In this study, equations for the calculation of erosion wear caused by ash particles on convective heat exchanger tubes of steam boilers are presented. A new, three-dimensional test arrangement was used in the testing of the erosion wear of convective heat exchanger tubes of steam boilers. When using the sleeve-method, three different tube materials and three tube constructions could be tested. New results were obtained from the analyses. The main mechanisms of erosion wear phenomena and erosion wear as a function of collision conditions and material properties have been studied. Properties of fossil fuels have also been presented. When burning solid fuels, such as pulverized coal and peat in steam boilers, most of the ash is entrained by the flue gas in the furnace. In bubbling and circulating fluidized bed boilers, particle concentration in the flue gas is high because of bed material entrained in the flue gas. Hard particles, such as sharp edged quartz crystals, cause erosion wear when colliding on convective heat exchanger tubes and on the rear wall of the steam boiler. The most important ways to reduce erosion wear in steam boilers is to keep the velocity of the flue gas moderate and prevent channelling of the ash flow in a certain part of the cross section of the flue gas channel, especially near the back wall. One can do this by constructing the boiler with the following components. Screen plates can be used to make the velocity and ash flow distributions more even at the cross-section of the channel. Shield plates and plate type constructions in superheaters can also be used. Erosion testing was conducted with three types of tube constructions: a one tube row, an in- line tube bank with six tube rows, and a staggered tube bark with six tube rows. Three flow velocities and two particle concentrations were used in the tests, which were carried out at room temperature. Three particle materials were used: quartz, coal ash and peat ash particles. Mass loss

  15. Heat flow, deep formation temperature and thermal structure of the Tarim Basin, northwest China

    Science.gov (United States)

    Liu, Shaowen; Lei, Xiao; Feng, Changge; Li, Xianglan

    2016-04-01

    Geothermal regime of a sedimentary basin not only provides constraint on understanding the basin formation and evolution, but also offers fundamental parameters for hydrocarbon resources assessment. As one of three Precambrian blocks in China, the Tarim craton is also a current hydrocarbon exploration target where the largest sedimentary basin (Tarim Basin) develops with great potential. Although considerable advancement of geothermal regime of this basin has been made during the past decades, nearly all the temperature data in previous studies are from the exploration borehole formation testing temperatures. Recently, we have conducted the steady-state temperature logging in the Tarim basin, and measured abundant rock thermal properties, enabling us to re-visit the thermal regime of this area with more confidence. Our results show that the present-day geothermal gradients for the Tarim Basin vary from 23 K/km to 27 K/km, with a mean of 22 K/km; the values of heat flow range from 40 mW/m2 to 49 mW/m2, with a mean of 43 mW/m2. These new data confirmed that the Tarim Basin has relatively low heat flow and shares similar geothermal regime with other Precambrian cratons in the world. In addition, the new temperatures from the steady-state logs are larger than the bottom hole temperatures (BHT) as 22 degree Celsius, indicating the thermal non-equilibrium for the BHTs used in previous studies. Spatial distribution of the estimated formation temperatures-at-depth of 1~5km within the basin is similar and mainly controlled by crystalline basement pattern. Generally, the temperatures at the depth of 1km range from 29 to 41 degree Celsius, with a mean of 35 degree Celsius; while the temperatures at 3km vary from 63 to 100 degree Celsius, and the mean is 82 degree Celsius; at 5km below the surface, the temperatures fall into a range between 90 and 160 degree Celsius, with a mean of 129 degree Celsius. We further proposed the long-term low geothermal background and large burial

  16. Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal

    Directory of Open Access Journals (Sweden)

    F. Lucazeau

    2012-06-01

    Full Text Available New temperature measurements from eight boreholes in the West African Craton (WAC reveal superficial perturbations down to 100 meters below the alteration zone. These perturbations are both related to a recent increase of the surface air temperature (SAT and to the site effects caused by fluids circulations and/or the lower conduction in the alterites. The ground surface temperature (GST inverted from the boreholes temperatures is stable in the past (1700–1940 and then dramatically increases in the most recent years (1.5 °C since 1950. This is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou, and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids or conductive (lower conductivity of laterite and of high-porosity sand perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these sites perturbations: all the eight boreholes temperatures logs can be interpreted with the same basal heat-flow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous boreholes measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a subhumid zone in southern Mali. Finally, the background heat-flow is low (30 ± 1 m Wm−2, which makes this part of the WAC more similar with the observations in the southern part (33 ± 8 m Wm−2 rather than with those in the northern part and in the PanAfrican domains where the surface heat-flow is 15–20 m Wm−2 higher.

  17. Direct numerical simulation of Taylor-Couette flow subjected to a radial temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Hao; Liu, Nansheng, E-mail: lns@ustc.edu.cn; Lu, Xiyun [Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Khomami, Bamin, E-mail: bkhomami@utk.edu [Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2015-12-15

    Direct numerical simulations have been performed to study the Taylor-Couette (TC) flow between two rotating, coaxial cylinders in the presence of a radial temperature gradient. Specifically, the influence of the buoyant force and the outer cylinder rotation on the turbulent TC flow system with the radius ratio η = 0.912 was examined. For the co-rotating TC flows with Re{sub i} (inner cylinder) =1000 and Re{sub o} (outer cylinder) =100, a transition pathway to highly turbulent flows is realized by increasing σ, a parameter signifying the ratio of buoyant to inertial force. This nonlinear flow transition involves four intriguing states that emerge in sequence as chaotic wavy vortex flow for σ = 0, wavy interpenetrating spiral flows for σ = 0.02 and 0.05, intermittent turbulent spirals for σ = 0.1 and 0.2, and turbulent spirals for σ = 0.4. Overall, the fluid motion changes from a centrifugally driven flow regime characterized by large-scale wavy Taylor vortices (TVs) to a buoyancy-dominated flow regime characterized by small-scale turbulent vortices. Commensurate changes in turbulence statistics and heat transfer are seen as a result of the weakening of large-scale TV circulations and enhancement of turbulent motions. Additionally, the influence of variation of the outer cylinder rotation, −500 < Re{sub o} < 500 in presence of buoyancy (σ = 0.1) with Re{sub i} = 1000, has been considered. Specifically, it is demonstrated that this variation strongly influences the azimuthal and axial mean flows with a weaker influence on the fluctuating fluid motions. Of special interest, here are the turbulent dynamics near the outer wall where a marked decrease of turbulence intensity and a sign inversion of the Reynolds stress R{sub rz} are observed for the strongly counter-rotating regimes (Re{sub o} = − 300 and −500). To this end, it has been shown that the underlying flow physics for this drastic modification are associated with the modification of the correlation

  18. In situ measurements of the spectral emittance of coal ash deposits

    International Nuclear Information System (INIS)

    The spectral emittance of deposits left by bituminous and sub-bituminous coals under oxidizing conditions have been measured in situ. Pulverized coal is injected into a down-fired entrained-flow reactor. Ash accumulates on a probe in the reactor effluent and radiation emitted by the ash layer is recorded using a Fourier transform infrared (FTIR) spectrometer. Values for the spectral emissive power emitted by the ash and the surface temperature of the ash are extracted from these data. These results are then used to calculate the spectral emittance of the deposit. The spectral emittances of ash deposits formed by burning Illinois no. 6 (bituminous) coal and Powder River Basin (sub-bituminous) coal were measured between 3000 and 500 wavenumbers. The spectral emittance of the deposit left by the bituminous coal has a constant value of approximately 0.46 between 3000 and 2400 wavenumbers. Between 2200 and 1200 wavenumbers, the spectral emittance of the deposit increases from approximately 0.47 to approximately 0.61. Between 1200 and 500 wavenumbers, the spectral emittance is relatively constant at 0.61. The spectral emittance of the deposit left by the sub-bituminous coal is also relatively constant between 3000 and 2400 wavenumbers at a value of 0.29. Between 2200 and 500 wavenumbers, the spectral emittance of deposits from the sub-bituminous coal increases from approximately 0.29 to 0.55. Differences between these spectral emittance measurements and those measured ex situ illustrate the importance of making in situ measurements. Band emittances were calculated using the measured spectral emittances, and band emittances of the deposits are reported as functions of temperature.

  19. DNS of thermocapillary flows based on two-scalar temperature representation

    Science.gov (United States)

    Bothe, Dieter; Ma, Chen

    2011-11-01

    The direct numerical simulation (DNS) of thermocapillary two-phase flow with free deformable interface requires the solution of the two-phase Navier-Stokes equations in 3D together with the energy balance. We employ the sharp interface model which is solved using an extended volume of fluid method, where the discretization is based on Finite Volumes. The energy equation is given in temperature form, where the temperature field is represented by two scalars, one for each phase. This way the averaging over grid cells is confined to the individual phases and, hence, a smearing of the temperature gradient jump is avoided. Interpolation of the temperature within interfacial cells, exploiting the energy transmission condition, yields accurate temperatures at the interface, which is of utmost importance for the calculation of thermocapillary forces. Here the position and orientation of the interface is approximated by piecewise linear interface construction (PLIC). This method is applied to investigate liquid films on locally heated planar, respectively heated structured substrates. The approach allows for the numerical simulation of evaporating flows coupled with thermal Marangoni effects.

  20. Removal of Cryptosporidium sized particle under different filtration temperature, flow rate and alum dosing

    Institute of Scientific and Technical Information of China (English)

    XU Guo-ren; Fitzpatrick S. B. Caroline; Gregory John; DENG Lin-yu

    2007-01-01

    Recent Cryptosporidium outbreaks have highlighted concerns about filter efficiency and in particular particle breakthrough. It is essential to ascertain the causes of Cryptosporidium sized particle breakthrough for Cryptosporidium cannot be destroyed by conventional chlorine disinfection. This research tried to investigate the influence of temperature, flow rate and chemical dosing on particle breakthrough during filtration. The results showed that higher temperatures and coagulant doses could reduce particle breakthrough. The increase of filtration rate made the residual particle counts become larger. There was an optimal dose in filtration and was well correlated to ζ potential.

  1. On computations of temperature dependent incompressible flows by high order methods

    Science.gov (United States)

    Pech, Jan

    2016-03-01

    Parallel vortex shedding from the heated cylinder as dependent on the cylinder temperature is investigated in numerical simulation. The computational scheme for the system of the incompressible Navier-Stokes equations coupled with the heat equation is presented. The scheme is based on the mixed implicit-explicit solver of the third order and the spectral element method for the spatial approximation. The results are compared with the experiments for flow of air and water. The Strouhal-Prandtl-Reynolds relationship and evolution of the separation angle as dependence on the temperature is the final result of the computations.

  2. Temperature in ideal gas mixtures in Couette flow: A maximum-entropy approach

    Energy Technology Data Exchange (ETDEWEB)

    Criado-Sancho, M. [Departamento de Ciencias y Tecnicas Fisicoquimicas, Facultad de Ciencias, UNED, 28040 Madrid (Spain); Jou, D. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain); Casas-Vazquez, J. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalonia (Spain)], E-mail: jose.casas@uab.es

    2008-03-24

    A binary mixture of ideal gases in Couette flow is studied in the framework of information theory. It is shown that if the total shear viscous pressure is imposed as a constraint, there is equipartition of energy between the different chemical species but not amongst the different spatial directions. In contrast, if a same shear rate is imposed on both species, there is no equipartition between species neither amongst spatial directions. In both situations, the thermodynamic temperature, defined from the Lagrange multiplier conjugated to the internal energy, is the same for both species, independently of the equality or not of their local-equilibrium temperature.

  3. Realization of a flux-flow DC-transformer using high temperature superconductors

    International Nuclear Information System (INIS)

    This paper reports on the first realization using high temperature superconducting films of the device proposed in 1965 by Giaever: the DC-DC transformer, which involves flux-flow vortex motion in two superimposed thin films, separated by a thin insulating layer. The device was fabricated using the ramp based multilayer technology from an YBa2Cu3O7 based SIS structure grown by pulsed laser deposition. Transport measurements exhibiting the coupling and decoupling phenomena between the two vortex arrays are obtained. We discuss the possibility of widening the working range of this device, which constitutes an important result in the effort to use high temperature superconductors for electronics. (orig.)

  4. Magnetohydrodynamics and radiation effects on the flow due to moving vertical porous plate with variable temperature

    International Nuclear Information System (INIS)

    The combined effects of magnetohydrodynamics and thermal radiations on unsteady flow of an electrically conducting fluid past an impulsively started infinite vertical porous plate with variable temperature is investigated. A magnetic field of uniform strength is applied along an axis perpendicular to the plate. The plate temperature is raised linearly with time. An exact solution is obtained by Laplace transformation technique. The dependence of the amplitude of velocity and skin-friction on various parameters are discussed in detail with the help of graphs. (author)

  5. Computer simulation of slightly rarefied gas flows driven by significant temperature variations and their continuum limit

    Science.gov (United States)

    Rogozin, O. A.

    2014-12-01

    A rigorous asymptotic analysis of the Boltzmann equation for small Knudsen numbers leads, in the general case, to more complicated sets of differential equations than widely used to describe the behavior of gas in terms of classical fluid dynamics. The present paper deals with such one that is valid for significant temperature variations and finite Reynolds numbers at the same time (slow nonisothermal flow equations). A finite-volume solver developed on the open-source CFD platform OpenFOAM is proposed for computer simulation of a slightly rarefied gas in an arbitrary geometry. Typical temperature-driven flows are considered as numerical examples. A force acting on uniformly heated bodies is studied as well.

  6. Heat and fluid flow through monodisperse spherical random packings: Pressure drop and temperature profile

    Energy Technology Data Exchange (ETDEWEB)

    Zaman, E.

    2009-07-01

    The heat and fluid flow through packings of spherical random particles is computationally studied via finite volume method. A variety of packings of spheres are generated using particulate dynamics simulation methods. Navier-stokes equations are solved for the fluid flow through the interstitium in such porous media. The effects of porosity on permeability and pressure drop are investigated. Pressure gradient within porous media is compared between simulations and the Ergun equation (for lower range of porosity), or the Stokes relation (for the higher range of porosity). In addition, the dependence of pressure gradient on particle diameter (pore size) is examined. On the other hand, the energy equation is solved to model the unsteady heat transfer through the interstitium of porous medium when a stream of hot fluid encounters the particles within porous media of constant temperature. In this context, the effect of pore size on the outlet temperature is investigated. (orig.)

  7. MOSS spectroscopic camera for imaging time resolved plasma species temperature and flow speed

    International Nuclear Information System (INIS)

    A MOSS (Modulated Optical Solid-State) spectroscopic camera has been devised to monitor the spatial and temporal variations of temperatures and flow speeds of plasma ion species, the Doppler broadening measurement being made of spectroscopic lines specified. As opposed to a single channel MOSS spectrometer, the camera images light from plasma onto an array of light detectors, being mentioned 2D imaging of plasma ion temperatures and flow speeds. In addition, compared to a conventional grating spectrometer, the MOSS camera shows an excellent light collecting performance which leads to the improvement of signal to noise ratio and of time resolution. The present paper first describes basic items of MOSS spectroscopy, then follows MOSS camera with an emphasis on the optical system of 2D imaging. (author)

  8. Computer simulation of slightly rarefied gas flows driven by significant temperature variations and their continuum limit

    CERN Document Server

    Rogozin, Oleg

    2014-01-01

    A rigorous asymptotic analysis of the Boltzmann equation for small Knudsen numbers leads, in the general case, to more complicated sets of differential equations than widely used to describe the behavior of gas in terms of classical fluid dynamics. The present paper deals with such one that is valid for significant temperature variations and finite Reynolds numbers at the same time (slow nonisothermal flow equations). A finite-volume solver developed on the open-source CFD platform OpenFOAM is proposed for computer simulation of a slightly rarefied gas in an arbitrary geometry. Typical temperature driven flows are considered as numerical examples. A force acting on uniformly heated bodies is studied as well.

  9. Numerical Investigation on Heat and Flow Characteristics of Temperature-Sensitive Ferrofluid in a Square Cavity

    OpenAIRE

    Moo-Yeon Lee; Jae-Hyeong Seo

    2013-01-01

    The objective of this paper is numerically to study the heat and flow characteristics of temperature-sensitive ferrofluid in the square cavity with and without the magnetic intensity. The numerical model was developed to predict the behavior of the ferrofluid using finite element method (FEM) and showed good agreement with the existing data within 5% at all Rayleigh number ranges from 103 to 106. Natural convection and heat transfer characteristics of the ferrofluids within the tested cavity ...

  10. Software of temperatures and flow acquisition in the RP-10 reactor

    International Nuclear Information System (INIS)

    The SAT software was developed due to the need for reliable measurements of temperature, pressure and flow for the thermal potential calibration of the RP-10. Using a PCI-MIO-16XE-10 board from National Instruments, signals are taken in pre-defined times by the user, and an operation report is automatically generated at the end of the acquisition. The objective of this work is based on showing the main characteristics of the software developed for this purpose

  11. Radiative, two-temperature simulations of low luminosity black hole accretion flows in general relativity

    OpenAIRE

    Sadowski, A.; Wielgus, M.; Narayan, R.; Abarca, D.; McKinney, J.C.

    2016-01-01

    We present a numerical method which evolves a two-temperature, magnetized, radiative, accretion flow around a black hole, within the framework of general relativistic radiation magnetohydrodynamics. As implemented in the code KORAL, the gas consists of two sub-components -- ions and electrons -- which share the same dynamics but experience independent, relativistically consistent, thermodynamical evolution. The electrons and ions are heated independently according to a standard prescription f...

  12. Film Thickness and Flow Properties of Resin-Based Cements at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Bagheri R.

    2013-06-01

    Full Text Available Statement of Problem: For a luting agent to allow complete seating of prosthetic restorations, it must obtain an appropriate flow rate maintaining a minimum film thickness. The performance of recently introduced luting agents in this regard has not been evaluated. Purpose: To measure and compare the film thickness and flow properties of seven resin-containing luting cements at different temperatures (37°C, 25°C and10°C. Material and Methods: Specimens were prepared from five resin luting cements; seT (SDI, Panavia F (Kuraray, Varioloink II (Ivoclar, Maxcem (Kerr, Nexus2 (Kerr and two resin-modified glass-ionomer luting cements (RM-GICs; GC Fuji Plus (GC Corporation, and RelyX Luting 2 (3 M/ESPE. The film thickness and flow rate of each cement (n=15 was determined using the test described in ISO at three different temperatures. Results: There was a linear correlation between film thickness and flow rate for most of the materials. Cooling increased fluidity of almost all materials while the effect of temperature on film thickness was material dependent. At 37°C, all products revealed a film thickness of less than 25µm except for GC Fuji Plus. At 25°C, all cements pro-duced a film thickness of less than 27 µm except for seT. At 10°C, apart from seT and Rely X Luting 2, the remaining cements showed a film thickness smaller than 20 µm.Conclusion: Cooling increased fluidity of almost all materials, however. the film thickness did not exceed 35 µm in either condition, in spite of the lowest film thickness being demonstrated at the lowest temperature.

  13. Prediction of Air Flow and Temperature Profiles Inside Convective Solar Dryer

    OpenAIRE

    Marian Vintilă; Adrian Gabriel Ghiauş; Viorel Fătu

    2014-01-01

    Solar tray drying is an effective alternative for post-harvest processing of fruits and vegetables. Product quality and uniformity of the desired final moisture content are affected by the uneven air flow and temperature distribution inside the drying chamber. The purpose of this study is to numerically evaluate the operation parameters of a new indirect solar dryer having an appropriate design based on thermal uniformity inside the drying chamber, low construction costs and easy accessibilit...

  14. Heat Transfer in Hydromagnetic Fluid Flow: Study of Temperature Dependence of Fluid Viscosity

    OpenAIRE

    Shit, G. C.; Sushil Kumar Ghosh; Prof. J. C. Misra

    2014-01-01

    Flow of a viscoelastic fluid through a channel with stretching walls in the presence of a magnetic field has been investigated. The viscosity of the fluid is assumed to vary with temperature. Convective heat transfer is considered along with viscous dissipation and Ohmic dissipation. The equations that govern the motion of the fluid and heat transfer are coupled and non-linear. The governing partial differential equations are reduced to a set of ordinary differential equations by using simila...

  15. Numerical simulation of moderator flow and temperature distributions in a CANDU reactor vessel

    International Nuclear Information System (INIS)

    This paper describes numerical predictions of the two-dimensional flow and temperature fields of an internally-heated liquid in a typical CANDU reactor vessel. Turbulence momentum and energy transport are simulated using the k-epsilon model. Both steady-state and transient results are discussed. The finite control volume analogues of the conservation equations are solved using a modified version of the TEACH code

  16. Shallow subsurface temperatures and some estimates of heat flow from the Colorado Plateau of northeastern Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Sass, J.H.; Stone, C.; Bills, D.J.

    1982-01-01

    Temperature data to depths of a few hundred meters were obtained from 29 wells in northeastern Arizona; 12 in the region surrounding the San Francisco Volcanic Field, 8 in the Black Mesa area, and 9 in the south-central Colorado Plateau which includes the White Mountains. Although there was evidence for local hydrologic disturbances in many temperature profiles, most wells provided an estimate of the conductive thermal gradient at the site. A few thermal conductivities were measured and were combined with published regional averages for the north-central part of the Colorado Plateau to produce crude estimates of regional heat flux. None of the wells was accessible below the regional aquifers. To these depths, heat flow in the area of the San Francisco Volcanic Field appears to be controlled primarily by regional lateral water movement having a significant downward vertical component of velocity. The mean heat flow of 27 +- 5 mWm/sup -2/ is only a third to a quarter of what we would expect in this tectonic setting. The heat that is being carried laterally and downward probably is being discharged at low enthalpy and low elevation in springs and streams of the Colorado Plateau and Mogollon Rim. In the vicinity of Black Mesa, heat-flow averages about 60 mWm/sup -2/, characteristics of the coal interior of the Colorado Plateau. North of the White Mountain Volcanic Field, the average heat flow is about 95 mWm/sup -2/.

  17. Agglomeration in Stripper Ash Coolers and Its Possible Remedial Solutions: a Case Study

    Science.gov (United States)

    Singh, Ravi Inder

    2016-04-01

    The bottom ash of circulating fluidized bed (CFB) boiler contains large amounts of physical heat. When low quality coals are used in these types of boilers, the ash content is normally more than 40 % and the physical heat loss is approximately 3 % if the bottom ash is discharged without cooling. Bottom ash cooler (BAC) is often used to treat the high temperature bottom ash to reclaim heat, and to facilitate the easily handling and transportation of ash. The CFB boiler at BLA Power, Newari, MP (India) is facing problems of clinker formation in strip ash coolers of plant since the installation of unit. These clinkers are basically agglomerates, which leads to defluidization of stripper ash cooler (BAC) units. There are two strip ash coolers in unit. Each strip ash cooler is capable of working independently. The proper functioning of both strip coolers is very important as it is going to increase the combustion efficiency of boiler by stripping of fine unburnt coal particles from ash, which are injected into the furnace. In this paper causes, characterization of agglomerates, thermo gravimetric analysis of fuel used, particular size distribution of coal and sand and possible remedial solution to overcome these agglomerates in strip ash coolers has also been presented. High temperature in compact separators, non uniform supply of coal and not removing small agglomerates from stripper ash cooler are among main causes of agglomeration in stripper ash cooler. Control of compact separator temperature, replacing 10-12 % of bed material and cleaning stripper ash cooler periodically will decrease agglomeration in stripper ash cooler of unit.

  18. Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

    International Nuclear Information System (INIS)

    This paper introduces the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70 C discharging from 136 mm hexagonal channels into a 1 x 1 x 1.7 m tank at atmospheric pressure. A 40 m-long, φ155 μm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points over a 0.76 x 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. Sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both. (orig.)

  19. Prediction of Air Flow and Temperature Profiles Inside Convective Solar Dryer

    Directory of Open Access Journals (Sweden)

    Marian Vintilă

    2014-11-01

    Full Text Available Solar tray drying is an effective alternative for post-harvest processing of fruits and vegetables. Product quality and uniformity of the desired final moisture content are affected by the uneven air flow and temperature distribution inside the drying chamber. The purpose of this study is to numerically evaluate the operation parameters of a new indirect solar dryer having an appropriate design based on thermal uniformity inside the drying chamber, low construction costs and easy accessibility to resources needed for manufacture. The research was focused on both the investigation of different operation conditions and analysis of the influence of the damper position, which is incorporated into the chimney, on the internal cabinet temperature and air flow distribution. Numerical simulation was carried out with Comsol Multiphysics CFD commercial code using a reduced 2D domain model by neglecting any end effects from the side walls. The analysis of the coupled thermal-fluid model provided the velocity field, pressure distribution and temperature distribution in the solar collector and in the drying chamber when the damper was totally closed, half open and fully open and for different operation conditions. The predicted results were compared with measurements taken in-situ. With progressing computing power, it is conceivable that CFD will continue to provide explanations for more fluid flow, heat and mass transfer phenomena, leading to better equipment design and process control for the food industry.

  20. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system.

    Science.gov (United States)

    Rydfjord, Jonas; Svensson, Fredrik; Fagrell, Magnus; Sävmarker, Jonas; Thulin, Måns; Larhed, Mats

    2013-01-01

    In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe), thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications. PMID:24204419

  1. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system

    Directory of Open Access Journals (Sweden)

    Jonas Rydfjord

    2013-10-01

    Full Text Available In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe, thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

  2. Analysis of flow fields, temperatures and ruthenium transport in the test facility

    International Nuclear Information System (INIS)

    Ruthenium transport experiments were conducted at VTT during years 2002- 2006. Experiments gave information about ruthenium behaviour in air ingress accident conditions. This study complements those experiments with an analysis of the flows and thermal fields in the test system. Temperature profiles were measured at the walls of the experimental facility. Computational fluid dynamics (CFD) simulations used the measured profiles and provided predictions of flows and temperatures inside the furnace. Ruthenium transport was also modelled with CFD. Thermal characterisation of the reactor demonstrated that buoyancy has a significant role during the cooling after the furnace. A hypothesis of the dominant role of RuO2 and RuO3 condensation on reactor walls gave simulation results that are in accordance with radiotracer measurements of deposition in experiments conducted with furnace at 1500K. Actually, RuO3 does not condensate, but it thermal decomposes to RuO2. This does not seem to have effect on result. Particle formation around the furnace exit could be detected from the comparison of modelling results with the measured profiles. In several other experiments ruthenium behaviour is dominated by other issues. These are related to the complex ruthenium chemistry that includes various surface reactions. Thermal equilibrium indicates significant gaseous RuO4 concentration around 1300 K. It seems that seed particles decreased the catalytic decomposition activity of RuO4 to RuO2 around this temperature pushing the gas concentration towards the equilibrium, and further give rise to gaseous RuO4 transport to low temperatures. At higher temperature increasing mass flow rate of RuO2 particles is likely to catalyse (decomposition) reaction of RuO4 to RuO2. (au)

  3. Flow distribution of pebble bed high temperature gas cooled reactors using large eddy simulation

    International Nuclear Information System (INIS)

    A High Temperature Gas-cooled Reactor (HTGR) is one of the renewed reactor designs to play a role in nuclear power generation. This reactor design concepts is currently under consideration and development worldwide. Since the HTGR concept offers inherent safety, has a very flexible fuel cycle with capability to achieve high burnup levels, and provides good thermal efficiency of power plant, it can be considered for further development and improvement as a reactor concept of generation IV. The combination of coated particle fuel, inert helium gas as coolant and graphite moderated reactor makes it possible to operate at high temperature yielding a high efficiency. In this study the simulation of turbulent transport for the gas through the gaps of the spherical fuel elements (fuel pebbles) will be performed. This will help in understanding the highly three-dimensional, complex flow phenomena in pebble bed caused by flow curvature. Under these conditions, heat transfer in both laminar and turbulent flows varies noticeably around curved surfaces. Curved flows would be present in the presence of contiguous curved surfaces. In the case of a laminar flow and of an appreciable effect of thermogravitional forces, the Nusselt (Nu) number depends significantly on the curvature shape of the surface. It changes with order of 10 times. The flow passages through the gap between the fuel balls have concave and convex configurations. Here the action of the centrifugal forces manifests itself differently on convex and concave parts of the flow path (suppression or stimulation of turbulence). The flow of this type has distinctive features. In such flow there is a pressure gradient, which strongly affects the boundary layer behavior. The transition from a laminar to turbulent flow around this curved flow occurs at deferent Reynolds (Re) numbers. Consequently, noncircular curved flows as in the pebble-bed situation, in detailed local sense, is interesting to be investigated. To the

  4. Sulfate resistance of high calcium fly ash concrete

    Science.gov (United States)

    Dhole, Rajaram

    Sulfate attack is one of the mechanisms which can cause deterioration of concrete. In general, Class C fly ash mixtures are reported to provide poor sulfate resistance. Fly ashes, mainly those belonging to the Class C, were tested as per the ASTM C 1012 procedure to evaluate chemical sulfate resistance. Overall the Class C fly ashes showed poor resistance in the sulfate environment. Different strategies were used in this research work to improve the sulfate resistance of Class C fly ash mixes. The study revealed that some of the strategies such as use of low W/CM (water to cementing materials by mass ratio), silica fume or ultra fine fly ash, high volumes of fly ash and, ternary or quaternary mixes with suitable supplementary cementing materials, can successfully improve the sulfate resistance of the Class C fly ash mixes. Combined sulfate attack, involving physical and chemical action, was studied using sodium sulfate and calcium sulfate solutions. The specimens were subjected to wetting-drying cycles and temperature changes. These conditions were found to accelerate the rate of degradation of concrete placed in a sodium sulfate environment. W/CM was found to be the main governing factor in providing sulfate resistance to mixes. Calcium sulfate did not reveal damage as a result of mainly physical action. Characterization of the selected fly ashes was undertaken by using SEM, XRD and the Rietveld analysis techniques, to determine the relation between the composition of fly ashes and resistance to sulfate attack. The chemical composition of glass represented on the ternary diagram was the main factor which had a significant influence on the sulfate resistance of fly ash mixtures. Mixes prepared with fly ashes containing significant amounts of vulnerable crystalline phases offered poor sulfate resistance. Comparatively, fly ash mixes containing inert crystalline phases such as quartz, mullite and hematite offered good sulfate resistance. The analysis of hydrated lime

  5. Effect of Coal Properties and Operation Conditions on Flow Behavior of Coal Slag in Entrained Flow Gasifiers: A Brief Review

    Energy Technology Data Exchange (ETDEWEB)

    Wang,Ping; Massoudi, Mehrdad

    2011-01-01

    Integrated gasification combined cycle (IGCC) is a potentially promising clean technology with an inherent advantage of low emissions, since the process removes contaminants before combustion instead of from flue gas after combustion, as in a conventional coal steam plant. In addition, IGCC has potential for cost-effective carbon dioxide capture. Availability and high capital costs are the main challenges to making IGCC technology more competitive and fully commercial. Experiences from demonstrated IGCC plants show that, in the gasification system, low availability is largely due to slag buildup in the gasifier and fouling in the syngas cooler downstream of the gasification system. In the entrained flow gasifiers used in IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter (as fly ash) is entrained with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. Therefore, it is preferable to minimize the quantity of fly ash and maximize slag. In addition, the hot raw syngas is cooled to convert any entrained molten fly slag to hardened solid fly ash prior to entering the syngas cooler. To improve gasification availability through better design and operation of the gasification process, better understanding of slag behavior and characteristics of the slagging process are needed. Slagging behavior is affected by char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio). The viscosity of the slag is used to characterize the behavior of the slag flow and is the dominating factor to determine the probability that ash particles will stick. Slag viscosity strongly depends on the temperature and chemical composition of the slag. Because coal has varying ash content and

  6. Speciation of Zinc in ash investigated by X-ray absorption spectroscopy; Zinks foerekomstformer i aska studerade med en roentgenabsorptionsspektrometrisk metod

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Noren, Katarina

    2008-06-15

    amounts of zinc sulphide or zinc chloride was found. In ash from combustion of MSW zinc is also present in oxide minerals. The modelling of EXAFS data indicated a combination dominated by silicate and containing small amounts of hydroxide or oxide to be the most probable speciation in FBC bottom ash and cyclone ash, i.e. the most silicate rich ashes. The FBC filter ash, i.e. the ash flow containing the smallest mineral particles and compounds that have condensed when the flue gas temperature has decreased, contains the same zinc species as the bottom and cyclone ashes with the addition of a small amount of chloride or sulphide. Fly ashes from two stoker fired MSW combustors were investigated and the results were somewhat different. For one of the ashes the data were very well described by a model based on Zn{sub 2}SiO{sub 4} and a small amount of ZnCl{sub 2}.

  7. Rice Husk Ash Derived Zeolite Blended with Water Hyacinth Ash for Enhanced Adsorption of Cadmium Ions

    Directory of Open Access Journals (Sweden)

    G. W. Mbugua

    2014-08-01

    Full Text Available In order to helpcurtail or imposesustained control to the offensive water hyacinth plant,it is essential to explore ways of generatingwater remediation materials from it. In the current study, the capacity and efficacy of water hyacinth ash (WHA,its insoluble residue (WHAR and rice husk ash (RHAto remove cadmium ionsand methylene blue from contaminated water was investigated. Mixtures of the two ashes were used to formulatezeolitic materialsby hydrothermal reactions. Material A, ZMA was prepared by using rice husk ash and the soluble portion of WHA while for material B, ZMB a mixture of equal amounts the two ashes including the insoluble fraction of WHA were used. Batch experiments was carried out to determine the effect of metal ion concentration, initial PH, contact time (t, temperature (T, shaking speed and adsorbent dose on percentage removal of Cd2+ and methylene blue by the ashes and their zeolitic products. The data obtained for adsorption of Cd2+ on RHA, ZMA, and ZMB was found to best fit in the Langmuir isotherm model while WHA and WHAR data best fitted in theFreundlich model. Adsorption capacities for cadmium on RHA, WHA, WHAR, ZMA and ZMB adsorbents ions were 3.745, 52.00, 56.89, 11.24 and 22.22mg/g respectively.The findings showed that incorporating the WHAR during synthesis of the zeolitic material enhanced its adsorption capacity and efficiency for Cd (II ions and methylene blue.

  8. Effects of gas temperature on nozzle damping experiments on cold-flow rocket motors

    Science.gov (United States)

    Sun, Bing-bing; Li, Shi-peng; Su, Wan-xing; Li, Jun-wei; Wang, Ning-fei

    2016-09-01

    In order to explore the impact of gas temperature on the nozzle damping characteristics of solid rocket motor, numerical simulations were carried out by an experimental motor in Naval Ordnance Test Station of China Lake in California. Using the pulse decay method, different cases were numerically studied via Fluent along with UDF (User Defined Functions). Firstly, mesh sensitivity analysis and monitor position-independent analysis were carried out for the computer code validation. Then, the numerical method was further validated by comparing the calculated results and experimental data. Finally, the effects of gas temperature on the nozzle damping characteristics were studied in this paper. The results indicated that the gas temperature had cooperative effects on the nozzle damping and there had great differences between cold flow and hot fire test. By discussion and analysis, it was found that the changing of mainstream velocity and the natural acoustic frequency resulted from gas temperature were the key factors that affected the nozzle damping, while the alteration of the mean pressure had little effect. Thus, the high pressure condition could be replaced by low pressure to reduce the difficulty of the test. Finally, the relation of the coefficients "alpha" between the cold flow and hot fire was got.

  9. Fire severity effects on ash extractable Total Phosphorous

    Science.gov (United States)

    Pereira, Paulo; Úbeda, Xavier; Martin, Deborah

    2010-05-01

    Phosphorous (P) is a crucial element to plant nutrition and limits vegetal production. The amounts of P in soil are lower and great part of this nutrient is absorbed or precipitated. It is well known that fire has important implications on P cycle, that can be lost throughout volatilization, evacuated with the smoke, but also more available to transport after organic matter mineralization imposed by the fire. The release of P depends on ash pH and their chemical and physical characteristics. Fire temperatures impose different severities, according to the specie affected and contact time. Fire severity is often evaluated by ash colour and this is a low-cost and excellent methodology to assess the fire effects on ecosystems. The aim of this work is study the ash properties physical and chemical properties on ash extractable Total Phosphorous (TP), collected in three wildfires, occured in Portugal, (named, (1) Quinta do Conde, (2) Quinta da Areia and (3) Casal do Sapo) composed mainly by Quercus suber and Pinus pinaster trees. The ash colour was assessed using the Munsell color chart. From all three plots we analyzed a total of 102 ash samples and we identified 5 different ash colours, ordered in an increasing order of severity, Very Dark Brown, Black, Dark Grey, Very Dark Grey and Light Grey. In order to observe significant differences between extractable TP and ash colours, we applied an ANOVA One Way test, and considered the differences significant at a p<0.05. The results showed that significant differences in the extractable TP among the different ash colours. Hence, to identify specific differences between each ash colour, we applied a post-hoc Fisher LSD test, significant at a p<0.05. The results obtained showed significant differences between the extractable TP from Very dark Brown and Black ash, produced at lower severities, in relation to Dark Grey, Very Dark Grey and Light Grey ash, generated at higher severities. The means of the first group were higher

  10. MAT 126 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    stylia

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MAT 126 Week 1 DQ 1 (Ash) MAT 126 Week 1 Quiz (Ash) MAT 126 Week 1 Written Assignment (Arithmetic and geometric sequence) (Ash) MAT 126 Week 2 DQ 1 (Ash) MAT 126 Week 2 DQ 2 (Ash) MAT 126 Week 2 Assignment Is It Fat Free (Ash) MAT 126 Week 2 Quiz (Ash) MAT 126 Week 3 DQ 1 (Ash) MAT 126 Week 3 DQ 2 (Ash) MAT 126 Week 3 Assignment Quadratic Equations (Ash) MAT 126 Week 3 Quiz (Ash) MAT 126...

  11. Temperature Measurement and Water Flow Calorimetry for the Neutral Beam Test Stand Operation at KAERI

    International Nuclear Information System (INIS)

    Temperature measurements during the beam line operation of the neutral beam test stand(NB-TS) is very important for the estimation of the absorbed energy by the beam line components such calorimeter and also for the temperature monitoring of the various components, and have been accomplished by the utilization of many of the thermocouples(TCs) installed onto the NB-TS and the data acquisition system(DAQ) based on the National Instruments' (NI) SCXI system. Preliminary estimations of the absorbed energy by the calorimeter during the beam extraction have been made. Greater efforts for the noise reduction in the TC signal acquisition has been made with partial success. We present the status of the temperature measurement and water flow calorimetry(WFC) related to the NB-TS operations

  12. Temperature effect on shear flow and thixotropic behavior of residual sludge from wastewater treatment plant

    Science.gov (United States)

    Hammadi, L.; Ponton, A.; Belhadri, M.

    2013-08-01

    The temperature and shear rate effects on rheological behavior of residual sludge from wastewater treatment plant was investigated in this work. The model of Herschel-Bulkley was used to fit the shear rate dependence of the shear stress. The temperature increase induced not only an increase in the yield stress and the flow index of sludge but also a decrease of the consistency index of sludge. The temperature dependence of limit viscosity at high shear rate of the residual sludge was fitted by an Arrhenius equation. For constant shear rate applied on the sludge at 20 °C a thixotropic behavior was observed and analyzed using a modified model of Herschel-Bulkley in which a structural parameter λ was included in order to account for the time-dependent effect.

  13. CFD analysis of moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor

    International Nuclear Information System (INIS)

    Highlights: • 3D CFD of vertical calandria vessel. • Spatial distribution of volumetric heat generation. • Effect of Archimedes number. • Non-dimensional analysis. - Abstract: Three dimensional computational fluid dynamics (CFD) analysis has been performed for the moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor under normal operating condition using OpenFOAM CFD code. OpenFOAM is validated by comparing the predicted results with the experimental data available in literature. CFD model includes the calandria vessel, calandria tubes, inlet header and outlet header. Analysis has been performed for the cases of uniform and spatial distribution of volumetric heat generation. Studies show that the maximum temperature in moderator is lower in the case of spatial distribution of heat generation as compared to that in the uniform heat generation in calandria. In addition, the effect of Archimedes number on maximum and average moderator temperature was investigated

  14. CFD analysis of moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kansal, Anuj Kumar, E-mail: akansal@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Joshi, Jyeshtharaj B., E-mail: jbjoshi@gmail.com [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Maheshwari, Naresh Kumar, E-mail: nmahesh@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Vijayan, Pallippattu Krishnan, E-mail: vijayanp@barc.gov.in [Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2015-06-15

    Highlights: • 3D CFD of vertical calandria vessel. • Spatial distribution of volumetric heat generation. • Effect of Archimedes number. • Non-dimensional analysis. - Abstract: Three dimensional computational fluid dynamics (CFD) analysis has been performed for the moderator flow and temperature fields inside a vertical calandria vessel of nuclear reactor under normal operating condition using OpenFOAM CFD code. OpenFOAM is validated by comparing the predicted results with the experimental data available in literature. CFD model includes the calandria vessel, calandria tubes, inlet header and outlet header. Analysis has been performed for the cases of uniform and spatial distribution of volumetric heat generation. Studies show that the maximum temperature in moderator is lower in the case of spatial distribution of heat generation as compared to that in the uniform heat generation in calandria. In addition, the effect of Archimedes number on maximum and average moderator temperature was investigated.

  15. Influence of microstructure on the room temperature flow behaviour of Mod. 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    The normalizing heat treatment conditions of T-91 grade steel were altered in order to get different austenite/martensite packet grain sizes. Tempering of the steel was carried out at (1) peak hardening temperature and (2) at temperature closer to commercial treatment. Tempering of these specimens, austenitized at a chosen temperature, at the two tempering temperatures resulted in the modification of the fine scale structure by the formation of different carbide types and their distribution. Tensile testing of these specimens (under all the three conditions) was conducted at ambient temperature in order to study the influence of the microstructures on the deformation behaviour. The flow stress, hardness and room temperature impact toughness showed an inverse relation with the martensite packet/austenite grain size. The deformation behavior of the specimens under the three heat treatment conditions was analyzed according to Ashby's model was made assuming. The slip length, λg, was estimated from the σ-ε1/2 plot and compared with the relevant microstructure parameters. The as-received material was seen to undergo aligatoring damage during cold rolling and a modification in their microstructure could render a defect free product. (author)

  16. The adsorption of HCl on volcanic ash

    Science.gov (United States)

    Gutiérrez, Xochilt; Schiavi, Federica; Keppler, Hans

    2016-03-01

    Understanding the interaction between volcanic gases and ash is important to derive gas compositions from ash leachates and to constrain the environmental impact of eruptions. Volcanic HCl could potentially damage the ozone layer, but it is unclear what fraction of HCl actually reaches the stratosphere. The adsorption of HCl on volcanic ash was therefore studied from -76 to +150 °C to simulate the behavior of HCl in the dilute parts of a volcanic plume. Finely ground synthetic glasses of andesitic, dacitic, and rhyolitic composition as well as a natural obsidian from Vulcano (Italy) served as proxies for fresh natural ash. HCl adsorption is an irreversible process and appears to increase with the total alkali content of the glass. Adsorption kinetics follow a first order law with rate constants of 2.13 ṡ10-6 s-1 to 1.80 ṡ10-4 s-1 in the temperature range investigated. For dacitic composition, the temperature and pressure dependence of adsorption can be described by the equation ln ⁡ c = 1.26 + 0.27 ln ⁡ p - 715.3 / T, where c is the surface concentration of adsorbed HCl in mg/m2, T is temperature in Kelvin, and p is the partial pressure of HCl in mbar. A comparison of this model with a large data set for the composition of volcanic ash suggests that adsorption of HCl from the gas phase at relatively low temperatures can quantitatively account for the majority of the observed Cl concentrations. The model implies that adsorption of HCl on ash increases with temperature, probably because of the increasing number of accessible adsorption sites. This temperature dependence is opposite to that observed for SO2, so that HCl and SO2 are fractionated by the adsorption process and the fractionation factor changes by four orders of magnitude over a temperature range of 250 K. The assumption of equal adsorption of different species is therefore not appropriate for deriving volcanic gas compositions from analyses of adsorbates on ash. However, with the experimental

  17. Erosion resistance of superalloys and different coatings exposed to particulate flows at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tabakoff, W. [Cincinnati Univ., OH (USA). Dept. of Aerosp. Eng. and Eng. Mech.

    1999-11-01

    The design and development of high performance turbomachinery operating in an ambient with solid particles require a thorough knowledge of the fundamental phenomenon associated with particulate flows. Because of the serious consequences of turbomachinery erosion on their performance and life, it is important to have reliable methods for predicting their erosion when solid particles are ingested with the incoming flow. Several studies, which are essential to predicting blade surface erosion intensity and pattern, have been conducted at the University of Cincinnati's Propulsion Laboratory over the past 25 years. This paper describes only some of the work done on erosion testing at high temperatures and velocities for different materials and coatings. The testing has been performed with a special high temperature erosion wind tunnel, which simulates the aerodynamic conditions on the blades. The coatings investigated are produced by chemical vapor deposition (CVD), physical vapor deposition (PVD), and other methods. Experimental studies were conducted at the University's high temperature erosion wind tunnel to investigate the erosion behavior of coatings exposed to different types of solid particles. Some of the following coatings were evaluated: rhodium platinum aluminized, SDG-2207 (super D-gun product), CVD coatings, including TiC, TiN, Al{sub 2}O{sub 3} and PVD coatings. The erosive wear of the samples was studied experimentally by exposing them to a particle-laden flow at velocities from 180 to 305 m s{sup -1}, temperatures from ambient to 815 C and impingement angles from 15 to 90 . (orig.)

  18. Synthesis and characterization of fly ash-zinc oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Kunal Yeole

    2014-04-01

    Full Text Available Fly ash, generated in thermal power plants, is recognized as an environmental pollutant. Thus, measures are required to be undertaken to dispose it in an environmentally friendly method. In this paper an attempt is made to coat zinc oxide nano-particles on the surface of fly ash by a simple and environmentally friendly facile chemical method, at room temperature. Zinc oxide may serve as effective corrosion inhibitor by providing sacrificial protection. Concentration of fly ash was varied as 5, 10 and 15 (w/w % of zinc oxide. It was found that crystallinity increased, whereas particle size, specific gravity and oil absorption value decreased with increased concentration of fly ash in zinc oxide, which is attributed to the uniform distribution of zinc oxide on the surface of fly ash. These nanocomposites can potentially be used in commercial applications as additive for anticorrosion coatings.

  19. Preliminary studies of coolant by-pass flows in a prismatic very high temperature reactor using computational fluid dynamics

    International Nuclear Information System (INIS)

    Three dimensional computational fluid dynamic (CFD) calculations for a 1/12 sector of a prismatic block through the core of a prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. It is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core. (author)

  20. Preliminary studies of coolant by-pass flows in a prismatic very high temperature reactor using computational fluid dynamics

    International Nuclear Information System (INIS)

    Three dimensional computational fluid dynamic (CFD) calculations of a typical prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. In addition, it is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core.

  1. An ion Doppler spectrometer instrument for ion temperature and flow measurements on SSPX

    International Nuclear Information System (INIS)

    A high-resolution ion Doppler spectrometer (IDS) has been installed on the sustained spheromak plasma experiment to measure ion temperatures and plasma flow. The system is composed of a 1 m focal length Czerny-Turner spectrometer with a diffraction grating line density of 2400 lines/mm, which allows for first order spectra between 300 and 600 nm. A 16-channel photomultiplier tube detection assembly combined with output coupling optics provides a spectral resolution of 0.0126 nm/channel. We calculate in some detail the mapping of curved slit images onto the linear detector array elements. This is important in determining the wavelength resolution and setting the optimum vertical extent of the slit. Also, because of the small wavelength window of the IDS, a miniature fiber-optic survey spectrometer sensitive to a wavelength range 200-1100 nm and having a resolution of 0.2 nm is used to obtain a time-integrated spectrum for each shot to verify specific impurity line radiation. Several measurements validate the systems operation. Doppler broadening of C III 464.72 nm line in the plasma shows time-resolved ion temperatures up to 250 eV for hydrogen discharges, which is consistent with neutral particle energy analyzer measurements. Flow measurements show a sub-Alfvenic plasma flow ranging from 5 to 45 km/s for helium discharges.

  2. Electrodialytic treatment of fly ash

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Pedersen, Anne Juul; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

    Heavy metals are removed from the fly ashes by an electrodialytic treatment with the aim of up-grading the ashes for reuse in stead of disposal in landfill.A great potential for upgrading of bio- and waste incineration ashes by electrodialytic treatment exists. In the future, the applicability of...

  3. Laminar heat and fluid flow characteristic with a modified temperature-dependent viscosity model in a rectangular duct

    International Nuclear Information System (INIS)

    The present study proposes a modified temperature-dependent non-Newtonian viscosity model and investigates the flow characteristics and heat transfer enhancement of the viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. The combined effects of temperature dependent viscosity, buoyancy, and secondary flow caused by the second normal stress difference are considered. Calculated Nusselt numbers by the modified temperature-dependent viscosity model give good agreement with the experimental results. The heat transfer enhancement of viscoelastic fluid in a rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference

  4. Cooling effect of high-temperature steam flow downstream from the turbine bypass valve

    International Nuclear Information System (INIS)

    The main goal of this study is to investigate the evaporation process of a coolant (water droplets) which is injected through spray nozzles mounted on a steam turbine bypass pipeline in a co-generator system. The study includes several important factors: (1) the effects of four elbows on the flow pattern and evaporation process of the water particles, (2) heat transfer that affects the steam temperature and also the evaporation rates, and (3) the effects of a perforated plate on the flow pattern and evaporation process. The investigation of the structure of liquid spray jets during the transition into the gaseous phase was accomplished by developing a physical model of a particle tracking technique to investigate evaporation processes of the liquid droplets in a highly turbulent flow. Through this research, numerous data have been acquired and analyzed for heat transfer mechanisms of the evaporation of the water droplets in the pipeline system along with the cooling of the steam flow. The results of the computations were verified by comparing them with theoretical models, and were shown to be quite reliable

  5. Experimental and analytic study on the core bypass flow in a very high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Hwan; Lim, Hong Sik; Tak, Nam Il; Jun, Ji Su; Kim, Chan Soo; Yun, Churl; Jo, Chang Keun; Lee, Won Jae [KAERI, Daejeon (Korea, Republic of)

    2011-12-15

    A multi-block and multi-layer bypass flow test facility was designed and constructed. Experiments using the facility were carried out for uniform and non-uniform gap distributions of test blocks to produce data for the validation of codes. Using independent models developed for GAMMA+ code in Korea and GAS-NET code in the US, analyses for the bypass experiment were performed and the results were compared. In addition, CFD benchmark calculations by using CFX code in Korea and STARCCM+ in the US were carried out for MIR experiments and the validity of CFD models were assessed. A model for the estimation of bypass flow gap size in VHTR core was developed. And three dimensional core thermo-fluid analysis model considering the bypass gap distribution was developed by using the GAMMA+ code, which was applied to a prismatic core, developed in nuclear hydrogen project in KAERI, to predict core flow distribution and maximum fuel temperature. Finally, two measures of bypass flow reduction were suggested and their performance was assessed by the experiment.

  6. Investigating the roles of core and local temperature on forearm skin blood flow.

    Science.gov (United States)

    Mallette, Matthew M; Hodges, Gary J; McGarr, Gregory W; Gabriel, David A; Cheung, Stephen S

    2016-07-01

    We sought to isolate the contributions of core and local temperature on forearm skin blood flow (SkBF), and to examine the interaction between local- and reflexive-mechanisms of SkBF control. Forearm SkBF was assessed using laser-Doppler flowmetry in eight males and eight females during normothermia and hyperthermia (+1.2°C rectal temperature). Mean experimental forearm temperature was manipulated in four, 5min blocks between neutral (A: 33.0°C) and warm (B: 38.5°C) in an A-B-A-B fashion during normothermia, and B-A-B-A during hyperthermia. Mean control forearm skin temperature was maintained at ~33°C. Finally, local heating to 44°C was performed on both forearms to elicit maximal SkBF. Data are presented as a percentage of maximal cutaneous vascular conductance (CVC), calculated as laser-Doppler flux divided by mean arterial pressure. No sex differences were observed in any CVC measures (P>0.05). During normothermia, increasing experimental forearm temperature to 38.5°C elevated CVC by 42±8%max (d=3.1, Pforearm temperature back down to 33.0°C reduced CVC by 36±7%max (d=2.5, Pforearm temperature to 38.5°C increased CVC by 25±6%max (d=1.9, Pforearm temperature to 33.0°C reduced CVC by 6±1%max (d=0.5, Pforearm temperature to 38.5°C increased CVC by 4±2%max (d=0.4, Pforearm temperature to 33.0°C reduced CVC by 8±2%max (d=0.7, P<0.001). Compared to normothermia, CVC responses to local temperature changes during hyperthermia were almost abolished (normothermia: d=1.9-3.1; hyperthermia: d=0.4-0.7). These data indicate that local temperature drives SkBF during normothermia, while reflexive mechanisms regulate SkBF during hyperthermia. PMID:27072118

  7. A study of fly ash-lime granule unfired brick

    Energy Technology Data Exchange (ETDEWEB)

    P. Chindaprasirt; K. Pimraksa [Khon Kaen University (Thailand). Department of Civil Engineering

    2008-02-15

    In this paper, the properties of fly ash-lime granule unfired bricks are studied. Granules were prepared from mixtures of fly ash and lime at fly ash to hydrated lime ratios of 100:0 (Ca/Si = 0.2), 95:5 (Ca/Si = 0.35) and 90:10 (Ca/Si = 0.5). After a period of moist curing, the microstructure and mineralogy of the granules were studied. Microstructure examination reveals that new phases in the form of needle-like particles are formed at the surface of granule. The granules were used to make unfired bricks using hydrothermal treatment at temperature of 130 {+-} 5{sup o}C and pressure of 0.14 MPa. The microstructures, mineralogical compositions, mechanical properties and environmental impact of bricks were determined. The results reveal that the strengths of unfired bricks are dependent on the fineness of fly ash. The strength is higher with an increase in fly ash fineness. The strengths of the fly ash-lime granule unfired brick are excellent at 47.0-62.5 MPa. The high strength is due to the formation of new products consisting mainly of hibschite and Al-substituted 11 {angstrom} tobermorite. The main advantage of utilization of granule is the ability to increase the pozzolanic reaction of fly ash through moisture retained in the granule. In addition, the heavy elements, in particular Cd, Ni, Pb and Zn are efficiently retained in the fly ash-lime granule unfired brick.

  8. Novel cobalt base superalloy and its high-temperature flow behavior

    Institute of Scientific and Technical Information of China (English)

    TANG Chunfeng; PAN Feng; QU Xuanhui; DUAN Baihua; WANG Tianjian; HE Xinbo

    2008-01-01

    A novel cobalt base superalloy containing titanium and aluminum was investigated through metallography, tensile test, and high-temperature isothermal compression deformation. The results show that proper content of titanium and aluminum with can improve the strength and ductility of the cobalt base superalloy. The Co3(Ti,Al) compound with L12 structure precipitates when the novel superalloy is aged at 800℃ for 20h. The ε phase with hcp structure also precipitates when the superalloy is deformed by 28% and then aged at 650℃ for 4h. The ε phase can exist at 800℃. The superalloy has excellent high-temperature mechanical properties. Its maximum flow stress at 850℃ is in the range of 360-475MPa when the strain rate is between 0.0021 and 2.1 s-1. The flow stress of the superalloy during high-temperature deformation can be described by the Zener-Hollomon parameter with a hot deformation activation energy of 397 kJ.mol-1.

  9. Effect of Ambient and Oxygen Temperature on Flow Field Characteristics of Coherent Jet

    Science.gov (United States)

    Liu, Fuhai; Zhu, Rong; Dong, Kai; Hu, Shaoyan

    2016-02-01

    The coherent jets are now used widely in electric arc furnace steelmaking process to increase the stirring ability, reaction rates, and energy efficiency. However, there has been limited research on the basic physics of the coherent jets. In the present study, the characteristics of flow field of supersonic coherent jet in hot and cold condition were studied. The total temperature and axial velocity were measured by combustion experiment. Flow field characteristics of supersonic coherent jet were simulated by Fluent software. The detailed chemical kinetic mechanism is presently used for the modeling of reactions. It consists of 53 species, plus Ar and N2, for a total of 325 reversible reactions. The present study showed that the shrouding flame decreases the entrainment of the ambient gas to the central supersonic jet, which results in a low expansion rate for the coherent supersonic jet. The higher ambient temperature can prolong the potential core of coherent jet and conventional jet. However, the potential core of coherent jet reduces with oxygen temperature increasing, which is opposite to conventional jet.

  10. Three-dimensional reconstruction method on the PDE exhaust plume flow flame temperature field

    Science.gov (United States)

    Zhang, Zhimin; Wan, Xiong; Luo, Ningning; Li, Shujing

    2010-10-01

    Pulse detonation engine (referred to as PDE) has many advantage about simple structure, high efficiency thermal [1] cycling etc. In the future, it can be widely used in unmanned aircraft, target drone, luring the plane, the imaginary target, target missiles, long-range missiles and other military targets. However, because the exhaust flame of PDE is complicated [2], non-uniform temperature distribution and mutation in real time, its 3-D temperature distribution is difficult to be measured by normal way. As a result, PDE is used in the military project need to face many difficulties and challenges. In order to analyze and improve the working performance of PDE, deep research on the detonation combustion process is necessary. However, its performance characteristic which is in non-steady-state, as well as high temperature, high pressure, transient combustion characteristics put forward high demands about the flow field parameters measurement. In this paper, the PDE exhaust flames temperature field is reconstructed based on the theory of radiation thermometry [3] and Emission Spectral Tomography (referred to as EST) [4~6] which is one branch of Optical CT. It can monitor the detonation wave temperature distribution out of the exhaust flames at different moments, it also provides authentication for the numerical simulation which directs towards PDE work performance, and then it provides the basis for improving the structure of PDE.

  11. Heat Transfer in Hydromagnetic Fluid Flow: Study of Temperature Dependence of Fluid Viscosity

    Directory of Open Access Journals (Sweden)

    G. C. Shit

    2014-01-01

    Full Text Available Flow of a viscoelastic fluid through a channel with stretching walls in the presence of a magnetic field has been investigated. The viscosity of the fluid is assumed to vary with temperature. Convective heat transfer is considered along with viscous dissipation and Ohmic dissipation. The equations that govern the motion of the fluid and heat transfer are coupled and non-linear. The governing partial differential equations are reduced to a set of ordinary differential equations by using similarity transformation. The transformed equations subject to the boundary conditions are solved by developing a suitable finite difference scheme. Numerical estimates of the flow and heat transfer variables are obtained by considering blood as the working fluid. The computational values are found to be in good agreement with those of previous studies.

  12. Microfiltration of red berry juice with thread filters: Effects of temperature, flow and filter pore size

    DEFF Research Database (Denmark)

    Bagger-Jørgensen, Rico; Casani, Sandra Dobon; Meyer, Anne Boye Strunge

    2002-01-01

    A series of experiments was conducted to demonstrate the applicability of a new Filtomat(R) thread filtration principle for microfiltration of semiprocessed blackcurrant juice and cherry juice. The effect of juice temperature (3-20C), flow (20-80 L/h), and filter pore size (3-10 mum) on the...... transmembrane pressure, juice turbidity, protein, sugar, and total phenols levels was evaluated in a lab scale microfiltration unit employing statistically designed factorial experiments. Thread microfiltration reduced significantly the turbidity of both juices. For blackcurrant juice, in all experiments, the...... turbidity was immediately reduced to the level required for finished juice without compromising either the protein, the sugar or the phenols content. High flow rates increased the turbidity in blackcurrant juice, but did not affect cherry juice quality. Filtomat(R) thread microfiltration therefore appears...

  13. CFD analysis of flow and temperature distribution inside the calandria of Advanced Heavy Water Reactor

    International Nuclear Information System (INIS)

    Passive systems are being examined for the future AHWR reactor designs. One of these systems is the passive moderator cooling system, which removes heat from the moderator in case of a Station Black Out (SBO). The heavy-water moderator gets heated due to the residual heat from the core structures and rises upward due to buoyancy. This is cooled down in a heat exchanger and returns back to Calandria, completing a natural circulation loop. The natural circulation should provide sufficient cooling to prevent the increase of moderator (Calandria) pressure beyond safe limits. In this paper CFD investigations are carried out to study the temperature distributions and flow distribution inside the Calandria using a three-dimensional CFD code, OpenFoam 2.2.0. The results provide a band of operable mass flow rates which are safe for operation by virtue of prediction of hot spots in the Calandria. (author)

  14. Evaluation of Vitrification Processing Step for Rocky Flats Incinerator Ash

    International Nuclear Information System (INIS)

    In 1997, Pacific Northwest National Laboratory (PNNL) staff developed a processing option for incinerator ash at the Rocky Flats Environmental Technology Sites (RFETS). This work was performed with support from Los Alamos National Laboratory (LANL) and Safe Sites of Colorado (SSOC). A description of the remediation needs for the RFETS incinerator ash is provided in a report summarizing the recommended processing option for treatment of the ash (Lucy et al. 1998). The recommended process flowsheet involves a calcination pretreatment step to remove carbonaceous material followed by a vitrification processing step for a mixture of glass tit and calcined incinerator ash. Using the calcination pretreatment step to remove carbonaceous material reduced process upsets for the vitrification step, allowed for increased waste loading in the final product, and improved the quality of the final product. Figure 1.1 illustrates the flow sheet for the recommended processing option for treatment of RFETS incinerator ash. In 1998, work at PNNL further developed the recommended flow sheet through a series of studies to better define the vitrification operating parameters and to address secondary processing issues (such as characterizing the offgas species from the calcination process). Because a prototypical rotary calciner was not available for use, studies to evaluate the offgas from the calcination process were performed using a benchtop rotary calciner and laboratory-scale equipment (Lucy et al. 1998). This report focuses on the vitrification process step after ash has been calcined. Testing with full-scale containers was performed using ash surrogates and a muffle furnace similar to that planned for use at RFETS. Small-scale testing was performed using plutonium-bearing incinerator ash to verify performance of the waste form. Ash was not obtained from RFETS because of transportation requirements to calcine the incinerator ash prior to shipment of the material. Because part of

  15. Assessment of the impact of radionuclides in coal ash

    International Nuclear Information System (INIS)

    An assessment of the potential environmental and health impacts of radionuclides in the coal fuel cycle is being conducted at Mound. This paper describes studies evaluating the potential for migration of radionuclides from ash disposal sites. Studies at a power plant burning western-US coal dealt with an assessment of potential radiation doses from coal ash ponds and leachate discharges of radionuclides from the ponds. Emanation of 222Rn from the ash is relatively low. The emanation of 222Rn from the ash pond (226Ra at 4.5pCi.g-1) is predicted to be about six times less than from soil (226Ra at 1pCi.g-1). Ash with 226Ra at 25pCi.g-1 would approximate emanation of 222Rn from soil. At 1000m from the centre of the ash pond area, 222Rn from the ash pond is predicted to be 1000 to 6000 times less than background (0.1 to 0.5pCi.ltr-1). Pathways exist for transport of radionuclides leached from ash into the aquifer beneath the holding ponds, but concentrations of radionuclides in water leaving the ponds are lower than concentrations in groundwater which is upgradient of the ponds. Leachability of the ash is quite low, on the order of 0.002% in one month, and flow of ash-sluicing water (3% of the volume of the ponds each day) has actually diluted normal background concentrations of radionuclides in the aquifer between the ponds and the adjacent river. (author)

  16. An Ambient Temperature Molten Sodium-Vanadium Battery with Aqueous Flowing Catholyte.

    Science.gov (United States)

    Liu, Caihong; Shamie, Jack S; Shaw, Leon L; Sprenkle, Vincent L

    2016-01-20

    In this study, we have investigated the key factors dictating the cyclic performance of a new type of hybrid sodium-based flow batteries (HNFBs) that can operate at room temperature with high cell voltages (>3 V), multiple electron transfer redox reactions per active ion, and decoupled design of power and energy. HNFBs are composed of a molten Na-Cs alloy anode, flowing aqueous catholyte, and a Na-β″-Al2O3 solid electrolyte as the separator. The surface functionalization of graphite felt electrodes for the flowing aqueous catholyte has been studied for its effectiveness in enhancing V(2+)/V(3+), V(3+)/V(4+), and V(4+)/V(5+) redox couples. The V(4+)/V(5+) redox reaction has been further investigated at different cell operation temperatures for its cyclic stability and how the properties of the solid electrolyte membrane play a role in cycling. These fundamental understandings provide guidelines for improving the cyclic performance and stability of HNFBs with aqueous catholytes. We show that the HNFB with aqueous V-ion catholyte can reach high storage capacity (∼70% of the theoretical capacity) with good Coulombic efficiency (90% ± 1% in 2-30 cycles) and cyclic performance (>99% capacity retention for 30 cycles). It demonstrates, for the first time, the potential of high capacity HNFBs with aqueous catholytes, good capacity retention and long cycling life. This is also the first demonstration that Na-β″-Al2O3 solid electrolyte can be used with aqueous electrolyte at near room temperature for more than 30 cycles. PMID:26720551

  17. Study on Free Surface and Channel Flow Induced by Low-Temperature Plasma via Lattice Boltzmann Method

    Science.gov (United States)

    Wan, Gang; Jin, Yong; Li, Haiyuan; Li, Baoming

    2016-03-01

    Active boundary layer flow control and boundary layer manipulation in the channel flow that was based on low temperature plasma were studied by means of a lattice Boltzmann method. Two plasma actuators were placed in a row to obtain the influence rule of their separation distance on the velocity profile at three locations and maximum velocity in the flow field. Two plasma actuators were placed symmetrically inside a channel to examine the effect of channel height and voltage on the velocity profile and flow rate. It was found that the channel height controls the distribution of flow velocity, which affected the flow rate and its direction. Increasing plasma voltage had a negative effect on the flow rate due to the generation of a larger and stronger flow vortex.

  18. Post-warm-up muscle temperature maintenance: blood flow contribution and external heating optimisation

    OpenAIRE

    Raccuglia, Margherita; Lloyd, Alex; Filingeri, Davide; Faulkner, Steve H; Hodder, Simon; Havenith, George

    2015-01-01

    Purpose Passive muscle heating has been shown to reduce the drop in post-warm-up muscle temperature (T m) by about 25 % over 30 min, with concomitant sprint/power performance improvements. We sought to determine the role of leg blood flow in this cooling and whether optimising the heating procedure would further benefit post-warm-up T m maintenance. Methods Ten male cyclists completed 15-min sprint-based warm-up followed by 30 min recovery. Vastus lateralis T m (T mvl) was measured at deep-, ...

  19. Low cryogen inventory, forced flow Ne cooling system with room temperature compression stage and heat recuperation

    CERN Document Server

    Shornikov, A; Wolf, A

    2014-01-01

    We present design and commissioning results of a forced flow cooling system utilizing neon at 30 K. The cryogen is pumped through the system by a room-temperature compression stage. To decouple the cold zone from the compression stage a recuperating counterflow tube-in-tube heat exchanger is used. Commissioning demonstrated successful condensation of neon and transfer of up to 30 W cooling power to the load at 30 K using only 30 g of the cryogen circulating in the system at pressures below 170 kPa.

  20. Design field controller for level, flow, temperature and networking using YOKOGAWA DCS

    International Nuclear Information System (INIS)

    The application of field controller is an emerging area on most engineering field. The digital field controller has been widely used in the industry since ages ago. In this project, distributed field controller is designed to measure temperature, level and flow of the system used in Industrial Automation using YOKOGAWA DCS network. Here local controller integrated with Distributed Control System by using Yokogawa CENTUM CS 3000. The field controller was designed based on the field plant. Apart from that, a networking was done through Ethernet, which work in dual redundancy

  1. ASH and NASH.

    Science.gov (United States)

    Scaglioni, F; Ciccia, S; Marino, M; Bedogni, G; Bellentani, S

    2011-01-01

    Non-alcoholic steatohepatitis (NASH) and alcoholic steatohepatitis (ASH) have a similar pathogenesis and histopathology but a different etiology and epidemiology. NASH and ASH are advanced stages of non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD). NAFLD is characterized by excessive fat accumulation in the liver (steatosis), without any other evident causes of chronic liver diseases (viral, autoimmune, genetic, etc.), and with an alcohol consumption ≤20-30 g/day. On the contrary, AFLD is defined as the presence of steatosis and alcohol consumption >20-30 g/day. The most common phenotypic manifestations of primary NAFLD/NASH are overweight/obesity, visceral adiposity, type 2 diabetes, hypertriglyceridemia and hypertension. The prevalence of NAFLD in the general population in Western countries is estimated to be 25-30%. The prevalence and incidence of NASH and ASH are not known because of the impossibility of performing liver biopsy in the general population. Up to 90% of alcoholics have fatty liver, and 5-15% of these subjects will develop cirrhosis over 20 years. The risk of cirrhosis increases to 30-40% in those who continue to drink alcohol. About 10-35% of alcoholics exhibit changes on liver biopsy consistent with alcoholic hepatitis. Natural histories of NASH and ASH are not completely defined, even if patients with NASH have a reduced life expectancy due to liver-related death and cardiovascular diseases. The best treatment of AFLD/ASH is to stop drinking, and the most effective first-line therapeutic option for NAFLD/NASH is non-pharmacologic lifestyle interventions through a multidisciplinary approach including weight loss, dietary changes, physical exercise, and cognitive-behavior therapy. PMID:21734385

  2. A Comparative study Of Catalityc Activity Of Heterogeneous Base Of Banana Stem Ash And Fly Ash On Production Of Biodiesel Byultrasonic

    Directory of Open Access Journals (Sweden)

    Marlinda

    2015-08-01

    Full Text Available Abstract The use of heterogeneous catalysts in the production of biodiesel provides many advantages due to heterogeneous catalysts can be easily separated from the product so that it can be reused. This research using heterogeneous catalysts derived from natural materials namely banana stem ash and coal fly ash containing alkali and alkaline earth elements. The preparation of catalyst from banana stem ash and coal fly ash used activator KOH 1.9 N and impregnation with KNO3 15 and then heated to a temperature of 550 0C for 3 hours. Results of preparation banana stem ash contains potassium of 36.52 and surface area of 41.901 m2g. This work presents the effect of ultrasonic assisted of waste cooking oil with methanol as solvent using banana stem ash and coal fly ash as catalyst. The diameter of catalyst particles of banana stem ash and coal fly ash varied at 50 100 150 200 and 250 mesh. The transesterification reaction was performed in the presence of ultrasonic operating frequency constant at 40 kHz methanol molar ratio to oil of 9 1 and reaction time of 30 minutes. The methyl ester biodiesel content of product was 93.26 of banana stems ash and 57 of coal fly ash respectively. The physical property was compared with the National Indonesia Standard SNI 2006 with a density viscosity cloud point flash point and cetane number.

  3. Theoretical relation between water flow rate in a vertical fracture and rock temperature in the surrounding massif

    CERN Document Server

    Maréchal, Jean-Christophe

    2010-01-01

    A steady-state analytical solution is given describing the temperature distribution in a homogeneous massif perturbed by cold water flow through a discrete vertical fracture. A relation is derived to express the flow rate in the fracture as a function of the temperature measured in the surrounding rock. These mathematical results can be useful for tunnel drilling as it approaches a vertical cold water bearing structure that induces a thermal anomaly in the surrounding massif. During the tunnel drilling, by monitoring this anomaly along the tunnel axis one can quantify the flow rate in the discontinuity ahead before intersecting the fracture. The cases of the Simplon, Mont Blanc and Gotthard tunnels (Alps) are handled with this approach which shows very good agreement between observed temperatures and the theoretical trend. The flow rates before drilling of the tunnel predicted with the theoretical solution are similar in the Mont Blanc and Simplon cases, as well as the flow rates observed during the drilling....

  4. MGT 330 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    alfoniz

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MGT 330 Week 1 Individual Assignment Functions of Management Paper (Ash) MGT 330 Week 1 DQ 1 (Ash) MGT 330 Week 1 DQ 2 (Ash) MGT 330 Week 1 DQ 3 (Ash) MGT 330 Week 1 Summary (Ash) MGT 330 Week 2 Team Assignment External Internal Factors Paper (Ash) MGT 330 Week 2 Individual Assignment Delegation (Ash) MGT 330 Week 2 Summary (Ash) MGT 330 Week 2 DQ 1 (Ash) MGT 330 Week 2 DQ 2 (Ash) MGT 330 W...

  5. Evaluating the flow processes in ultrafine-grained materials at elevated temperatures

    Directory of Open Access Journals (Sweden)

    Megumi Kawasaki

    2013-06-01

    Full Text Available When polycrystalline materials are tested in tension at elevated temperatures, the flow mechanisms depend upon various parameters including the temperature of testing, the applied stress and the material grain size. The plotting of deformation mechanism maps is a procedure used widely in displaying and interpreting the creep properties of conventional coarse-grained metals but there have been few attempts to date to use this same procedure for ultrafine-grained and nanocrystalline materials produced through the application of severe plastic deformation (SPD. This report examines the potential for using deformation mechanism mapping for materials processed by SPD and presents examples for materials processed using equal-channel angular pressing and high-pressure torsion.

  6. Prediction of Pressure, Temperature, and Velocity Distribution of Two-Phase Flow in Oil Wells

    Energy Technology Data Exchange (ETDEWEB)

    Cazarez-Candia, Octavio [Programa de Yacimientos Naturalmente Fracturados, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, CP 07730, Mexico D.F. (Mexico); Vasquez-Cruz, Mario A. [Gerencia de Reservas de Hidrocarburos, PEMEX, Av. Marina Nacional No. 329, Col. Huasteca, C.P. 11311, Mexico D.F. (Mexico)

    2005-03-15

    In this work, a one-dimensional, time-dependent homogeneous mathematical model is presented, which can be used for determining the pressure, temperature, and velocity distributions of two-phase flow with three components (water-oil and gas) in oil wells. The numerical solution of the mathematical model, which consists of mass, momentum, and energy conservation equations, is based on the finite difference technique in the implicit scheme. The thermodynamic and transport properties of the fluids are estimated by black oil PVT correlations. The contribution of the terms of the conservation equations to the prediction of field data is studied. As a result, it was observed that the convective terms do not affect significantly the results of the present model. However, the terms in the energy equation containing the Joule-Thomson coefficient affect sensitively the prediction of temperature, but not the prediction of pressure. Numerical results are in agreement with field data and theoretical results reported in the literature.

  7. Measurements of local temperature distributions in rod bundles with sodium flow

    International Nuclear Information System (INIS)

    In an electrically heated 19-rod bundle (P/D = 1.30, W/R = 1.40) with sodium flow the three-dimensional temperature fields in the rod clads were measured. The main characteristics of the test section are three adjacent heater rods in the duct wall zone instrumented on four measuring planes and rotatable by 3600 under full power conditions; furthermore spacer grids which are axially movable, and a system allowing to bow one heater rod over the last third of its heated length. The results of measurements of the azimuthal temperature variations of the rotatable rods are presented for different operating conditions (80 2), different spacer grid positions relative to the measuring planes and different bowing positions of one rod. For better understanding of the experimental results cross sections of the 19-rod bundle were prepared. It became evident, that a well-known bundle geometry is very important for the interpretation of the experimental results. (orig.)

  8. Control of dispersed-phase temperature in plasma flows by the spectral-brightness pyrometry method

    Science.gov (United States)

    Dolmatov, A. V.; Gulyaev, I. P.; Gulyaev, P. Yu; Iordan, V. I.

    2016-02-01

    In the present work, we propose a new method for measuring the distribution of temperature in the ensembles of condensed-phase particles in plasma spray flows. Interrelation between the spectral temperature of the particles and the distribution of camera brightness signal is revealed. The established inter-relation enables an in-situ calibration of measuring instruments using the objects under study. The spectral-brightness pyrometry method was approbated on a Plazer plasma-arc wire spraying facility at the Paton Institute of Electrical Welding (Ukrainian Academy of Sciences, Kiev) and on the Thermoplasma 50-1 powder spraying facility at the Institute of Theoretical and Applied Mechanics (Russian Academy of Sciences, Siberian Branch, Novosibirsk). The work was supported by the Russian Foundation for Basic Research (Grants Nos. 14-08-90428 and 15-48-00100).

  9. Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

    Directory of Open Access Journals (Sweden)

    Nicolas Craquelin

    2010-12-01

    Full Text Available We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  10. Magnetic Resonance Flow Velocity and Temperature Mapping of a Shape Memory Polymer Foam Device

    Energy Technology Data Exchange (ETDEWEB)

    Small IV, W; Gjersing, E; Herberg, J L; Wilson, T S; Maitland, D J

    2008-10-29

    Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

  11. Flow of Temperature-dependent Viscous Fluid Between Parallel Heated Walls: Exact Analytical Solutions in the Presence of Viscous Dissipation

    Directory of Open Access Journals (Sweden)

    K. S. Adegbie

    2007-01-01

    Full Text Available We examine steady incompressible flow of viscous liquids between parallel heated walls of plane Couette device. The temperature of the upper and lower walls of the device are maintained at T = Tb and T = T0 respectively. Of a particular interest are exact analytical solutions of the coupled non-linear differential equations resulting from plane Couette flow obtained for the temperature and velocity distributions respectively. The criterion for which the solutions are valid was determined by the temperature difference, α, between the upper and lower walls. The analysis reveals that the shear stress obtained at the walls exists when the temperature difference α> 0.

  12. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    To study the influence of local conditions on the reaction between gaseous KCl and kaolin or coal fly ash experiments were done on CHECs electrically heated entrained flow reactor, which can simulate the local conditions in suspension fired boilers. The experimental results were compared with model...... studied. Due to not completely well controlled conditions during the experiments only preliminary conclusions can be provided. For experiments done at 1100°C with a molar ratio of K/Si=0.3 and a residence time of 1.07s approximately 80% of potassium from KCl reacted with kaolin. A changed temperature...

  13. Dynamic On-Chip micro Temperature and Flow Sensor for miniaturized lab-on-a-chip instruments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to design, fabricate, and characterize a Dynamic On-Chip Flow and Temperature Sensor (DOCFlaTS) to mature and enable miniaturized...

  14. Experimental study of forced convection heat transfer during upward and downward flow of helium at high pressure and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Valentin; Narbeh Artoun; Masahiro Kawaji; Donald M. McEligot

    2015-08-01

    Fundamental high pressure/high temperature forced convection experiments have been conducted in support of the development of a Very High Temperature Reactor (VHTR) with a prismatic core. The experiments utilize a high temperature/high pressure gas flow test facility constructed for forced convection and natural circulation experiments. The test section has a single 16.8 mm ID flow channel in a 2.7 m long, 108 mm OD graphite column with four 2.3kW electric heater rods placed symmetrically around the flow channel. This experimental study presents the role of buoyancy forces in enhancing or reducing convection heat transfer for helium at high pressures up to 70 bar and high temperatures up to 873 degrees K. Wall temperatures have been compared among 10 cases covering the inlet Re numbers ranging from 500 to 3,000. Downward flows display higher and lower wall temperatures in the upstream and downstream regions, respectively, than the upward flow cases due to the influence of buoyancy forces. In the entrance region, convection heat transfer is reduced due to buoyancy leading to higher wall temperatures, while in the downstream region, buoyancyinduced mixing causes higher convection heat transfer and lower wall temperatures. However, their influences are reduced as the Reynolds number increases. This experimental study is of specific interest to VHTR design and validation of safety analysis codes.

  15. Fire vegetative ash and erosion in the Mediterranean areas. State of the art and future perspectives

    Science.gov (United States)

    Pereira, Paulo; Cerdà, Artemi

    2013-04-01

    erosion. At this point we are dealing with a complex interaction since interactions, since low severity fires due ash, and high severity fires, due temperature induce soil hydrophobicity. After the fire, other ash properties may interact with soil erosion, as particulate size, and chemical composition, that can induce soil particulates flocculation or dispersion. Ash chemistry is strongly related with fire severity (Pereira et al., 2012). Further studies may be directed in the complex interaction between ash physico-chemical properties interaction with the degree of fire impacts on soil. These and other ideas will be discussed during the session. Acknowledgements, The authors appreciated the support of the project "Litfire", Fire effects in Lithuanian soils and ecosystems (MIP-048/2011) funded by the Lithuanian Research Council and FUEGORED (Spanish Network of Forest Fire Effects on Soils http://grupo.us.es/fuegored/). References Bodi, M., Doerr, S., Cerdà, A., Mataix-Solera, J. (2012) Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil. Geoderma 191: 14-13. Bodi, M., Mataix-Solera, J., Doerr, S., Cerdà, A. (2011) The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic matter content. Geoderma, 160, 599-607. Cerdà, A., Doerr, S.H. (2008). The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Onda Y, Dietrich WE, Booker F. 2008. Evolution of overland flow after a severe forest fire, Point Reyes, California. Catena. 72, 13-20. Pereira, P., Bodi. M., Úbeda, X., Cerdà, A., Mataix-Solera, J., Balfour, V, Woods, S. (2010) Las cenizas y el ecosistema suelo, In: Cerdà, A. Jordan, A. (eds) Actualización en métodos y técnicas para el estudio de los suelos afectados por incendios forestales, 345-398. Càtedra de Divulgació de la Ciència. Universitat de Valencia. ISBN: 978

  16. Suspension-firing of wood with coal ash addition: Probe measurements of ash deposit build-up at Avedøre Power Plant (AVV2)

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Jappe Frandsen, Flemming;

    This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood-firing....... Investigations of deposit formation rate were made by use of an advanced online ash deposition/shedding probe. Quantification of ash deposition and shedding was made via deposit mass uptake signals obtained from the deposit probe. The influence of coal ash, flue gas temperature, probe surface temperature...... oC), deposit removal through surface melting was not identified. SEM-EDS analysis of the deposits showed significant presence of Ca, Al and Si, indicating that a significant amount of K has been captured by coal ash to form deposits rich in calcium-aluminum-silicates, and possible release of Cl...

  17. On the application of the method of turbulent flow to transient and quasi-stationary flow calculations in high temperature reactors with spherical fuel elements

    International Nuclear Information System (INIS)

    For the calculation of flows in high-temperature reactors and of their temperature behavior the equations of the method of turbulent flow in the primitive form are derived for inhomogeneous regions. This system of equations is appropriate for the investigation of transient and quasi-stationary phenomena in pebble beds. By modification of the flow function in parallel arranged reflector channels a parallel flow can be simulated. For simplification the flow in region with a smaller pressure loss is assumed to be a potential flow. For the numerical solution of the time-dependent convective parts of the system of equations a number of explicit and implicit difference methods are compared. If the method using UP-WIND differences is taken to be an interpolation method the introduction of an extension becomes possible, which together with preliminary integration of the fictional terms allows to apply larger time steps. The algebraic system of equations for numerical calculation of a steady flow field also is established by formation of UP-WIND differences for the convective terms. By mathematical verification of some examples the applicability of the mathematical model for flow problems in pebble beds with forced or natural convection is shown. (orig.)

  18. Investigation of temperature fluctuations caused by steam-water two-phase flow in pressurizer spray piping

    International Nuclear Information System (INIS)

    In a PWR plant, a steam-water two-phase flow may possibly exist in the pressurizer spray pipe under a normal operating condition since the flow rate of the spray water is not sufficient to fill the horizontal section of the pipe completely. Initiation of high cycle fatigue cracks is suspected to occur under such thermally stratified two phase flow conditions due to cyclic thermal stress fluctuations caused by oscillations of the water surface. Such oscillations cannot be detected by the measurement of temperature on outer surface of the pipe. In order to clarify the flow and thermal conditions in the pressurizer spray pipe and assess their impact on the pipe structure, an experiment was conducted for a steam-water flow at a low flow rate using a mock-up pressurizer spray pipe. The maximum temperature fluctuation of about 0.2 times of the steam-water temperature difference was observed at the inner wall around water surface in the test section. Visualization tests were conducted to investigate the temperature fluctuation phenomena. It was shown that the fluid temperature fluctuations were not caused by the waves on the water surface, but were caused by liquid temperature fluctuations in water layer below the interface. The influence of small amount of non-condensable gas dissolved in the reactor coolant on the liquid temperature fluctuation phenomena was investigated by injecting air into the experimental loop. The air injection attenuated the liquid temperature fluctuations in the water layer since the condensation was suppressed by the non-condensable gas. It is not expected that wall temperature fluctuation in the actual PWR plant may exceed the temperature equivalent to the fatigue limit stress amplitude when it is assumed to be proportional to the steam-water temperature difference. (author)

  19. Non-Uniformity of the Combustor Exit Flow Temperature in Front of the Gas Turbine

    Directory of Open Access Journals (Sweden)

    Błachnio Józef

    2014-12-01

    Full Text Available Various types of damages to gas-turbine components, in particular to turbine blades, may occur in the course of gas turbine operation. The paper has been intended to discuss different forms of damages to the blades due to non-uniformity of the exit flow temperature. It has been shown that the overheating of blade material and thermal fatigue are the most common reasons for these damages. The paper presents results from numerical experiments with use of the computer model of the aero jet engine designed for simulations. The model has been purposefully modified to take account of the assumed non-homogeneity of the temperature field within the working agent at the turbine intake. It turned out that such non-homogeneity substantially affects dynamic and static properties of the engine considered as an object of control since it leads to a lag of the acceleration time and to increase in fuel consumption. The summarized simulation results demonstrate that the foregoing properties of a jet engine are subject to considerable deterioration in pace with gradual increase of the assumed non-homogeneity of the temperature field. The simulations made it possible to find out that variations of the temperature field nonhomogeneity within the working agent at the turbine intake lead to huge fluctuation of the turbine rpm for the idle run.

  20. Unsteady Hydromagnetic Flow of a Heat Absorbing Dusty Fluid Past a Permeable Vertical Plate with Ramped Temperature

    Directory of Open Access Journals (Sweden)

    m Das

    2014-01-01

    Full Text Available The unsteady flow and heat transfer of a viscous incompressible, electrically conducting dusty fluid past vertical plate under the influence of a transverse magnetic field is studied with a view to examine the combined effects of suction, heat absorption and ramped wall temperature. The temperature of the wall is assumed to have a temporarily ramped profile which goes on increasing up to a certain time limit and then becomes constant. To investigate the effect of rampedness in wall temperature, the solution for the flow past an isothermal wall is also obtained. The governing partial differential equations are solved using Laplace transformation technique in which the inversion is obtained numerically using Matlab. To validate the results of numerical inversion a comparison between the numerical and analytical values of fluid and particle temperatures and Nusselt number is also presented. The effects of pertinent flow parameters affecting the flow and heat transfer are investigated with the help of graphs and tables. It is found that the increase in suction, heat absorption and particle concentration contribute in thinning the thermal and momentum boundary layers and the velocity and temperature for both the fluid and particle phases are higher in the case of a flow past an isothermal plate than that of a flow past a plate with ramped temperature.

  1. Rapid response sensor to monitor the temperature and flow of liquid metals

    International Nuclear Information System (INIS)

    Two forms of a sensor capable of simultaneously monitoring the temperature and flow of liquid metal coolants within a reactor are described. They operate by measuring the coupling impedances between the sensor and the surrounding electrically conductive coolant. Since the system utilises electrical rather than thermal properties, the response to perturbations is rapid, typically displaying the changed conditions within a few milliseconds. The first form of the sensor was designed to operate whilst protected by a thick walled service tube positioned in the reactor coolant. Providing bends in the tube had a radius greater than 70 cm, the sensor could be removed for inspection and maintenance if necessary. The second sensor was fitted inside a streamlined NaK proof capsule. This was inserted directly into the coolant outlet stream of a fuel pin assembly in the Dounreay Fast Reactor. In this form the sensor successfully monitored flow, entrained gas and temperature excursions during the final operating cycle of D.F.R. (author)

  2. Effect of local cooling on skin temperature and blood flow of men in Antarctica

    Science.gov (United States)

    Naidu, M.; Sachdeva, U.

    1993-12-01

    Alterations to the finger skin temperature (Tsk) and blood flow (FBF) before and after cold immersion on exposure to an Antarctic environment for 8 weeks were studied in 64 subjects. There was a significant fall in Tsk and increase in finger blood flow after 1 week of Antarctic exposure. The Tsk did not further change even after 8 weeks of stay in Antarctica but a significant increase in FBF was obtained after 8 weeks. The cold immersion test was performed at non-Antarctic and Antarctic conditions by immersing the hand for 2 min in 0 4° C cold water. In the non-Antarctic environment the Tsk and FBF dropped significantly ( P vasoconstriction response. Interestingly after 8 weeks of stay in Antarctic conditions, the skin temperature dropped ( P < 0.001) but the cold induced fall in FBF was inhibited. Based on these observations it may be hypothesized that continuous cold exposure in Antarctica results in vasodilatation, which overrides the stronger vasoactive response of acute cold exposure and thus prevents cold injuries.

  3. Description of turbulent velocity and temperature fields of single phase flow through tight rod bundles

    International Nuclear Information System (INIS)

    A two-dimensional procedure, VANTACY-II, describing the turbulent velocity and temperature fields for single phase flow in tight lattices is presented and validated. The flow is assumed to be steady, incrompressible and hydraulic and thermal fully developed. First, the state of art of turbulent momentum and heat transport in tight lattices is documented. It is shown that there is a necessity for experimental investigations in the field of turbulent heat transport. The presented new procedure is based on the turbulence model VELASCO-TUBS by NEELEN. The numerical solution of the balance equations is done by the finite element method code VANTACY by KAISER. The validation of the new procedure VANTACY-II is done by comparing the numerically calculated data for the velocity and temperature fields and for natural mixing with the experimental data of SEALE. The comparison shows a good agreement of experimental and numerically computed data. The observed differences can be mainly attributed to the model of the turbulent PRANDTL number used in the new procedure. (orig.)

  4. Effect of electronic excitation on high-temperature flows behind strong shock waves

    International Nuclear Information System (INIS)

    In the present paper, a strongly non-equilibrium one-dimensional steady-state flow behind the plane shock wave is studied. We consider a high-temperature chemically reacting five-component ionized mixture of nitrogen species (N2/N22/N/N+/e−) taking into account electronic degrees of freedom in N and N+ (170 and 625 electronic energy levels respectively), and electronic-rotational-vibrational modes in N2 and N2+ (5 and 7 electronic terms). Non-equilibrium reactions of ionization, dissociation, recombination and charge-transfer are included to the kinetic scheme. The system of governing equations is written under the assumption that translation and internal energy relaxation is fast whereas chemical reactions and ionization proceed on the macroscopic gas-dynamics time-scale. The developed model is applied to simulate the flow behind a plane shock wave under initial conditions characteristic for the spacecraft re-entry from an interplanetary flight (Hermes and Fire II experiments). Fluid-dynamic parameters behind the shock wave as well as transport coefficients and the heat flux are calculated for the (N2/N2+/N/N+/e−) mixture. The effect of electronic excitation on kinetics, dynamics and heat transfer is analyzed. Whereas the contribution of electronic degrees of freedom to the flow macroparameters is negligible, their influence on the heat flux is found to be important under conditions of Hermes re-entry

  5. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Dockter, B.A.; Hurley, J.P.; Watne, T.A.; Katrinak, K.A.; O`Keefe, C.A. [North Dakota Univ., Grand Forks, ND (United States). Energy and Minerals Research Center

    1996-12-31

    Large-scale hot-gas testing over the past several years has revealed numerous cases of cake buildup on filter elements that have been difficult, if not impossible to remove. At times, the cake can bridge between candle filters, leading to high filter failure rates. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature contribute to difficulty in removing the cake. It is speculated that chemical as well as physical effects are playing a role in leading the ash to bond to the filter or to itself. The Energy and Environmental research Center (EERC) at the University of North Dakota is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The objectives of this overall project are threefold: first, to determine the mechanisms by which difficult-to-clean ash is formed; second, to develop a method to determine the rate of blinding/bridging based on fuel and sorbent properties and operating conditions; finally, to provide suggestions fro ways to prevent filter blinding by the troublesome ash. The projects consists of four tasks: field sampling and archive sample analyses, laboratory-scale testing, bench-scale testing, and model and database development testing. This paper present preliminary data from Task 2 on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions.

  6. MAT 221 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    mirat

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MAT 221 Week 1 Assignment 1 Simplifying Expressions (Ash) MAT 221 Week 1 DQ 1 Evaluating Algebraic Expressions (Ash) MAT 221 Week 2 Assignment 2 Inequalities (Ash) MAT 221 Week 2 DQ 1 Formulas (Ash) MAT 221 Week 3 Assignment 3 Two-Variable Inequality (Ash) MAT 221 Week 3 DQ 1 Parallel and Perpendicular (Ash) MAT 221 Week 4 Assignment 4 Financial Polynomials (Ash) MAT 221 Week 4 DQ 1 Initial Investme...

  7. Intrinsic reactivity of biomass-derived char under steam gasification conditions. Potential of wood ash as catalyst.

    NARCIS (Netherlands)

    Nanou, Pavlina; Gutierrez Murillo, Hector E.; Swaaij, van Wim P.M.; Rossum, van Guus; Kersten, Sascha R.A.

    2013-01-01

    The influence of ash on the steam gasification rate of pine wood derived char particles in the temperature range 600–800 °C is investigated. Ash derived from pine wood or specific ash components were added to the pine-wood (before pyrolysis) or to the produced char (after pyrolysis) via physical mix

  8. Numerical simulation of seepage flow field in groundwater source heat pump system and its influence on temperature field

    Institute of Scientific and Technical Information of China (English)

    Jihua HU; Yanjun ZHANG; Danyan DU; Gang WU; Ziwang YU; Chen WANG; Fuquan NI

    2008-01-01

    Energy utilization in the aquifers is a new technology closely related to development of heat pump technique. It is significant for the flow distribution to be predicted in the aquifer surrounding the Groundwater Source Heat Pump System (GSHPS). The authors presented a new concept of "flow transfixion" by analyzing general features of aquifers, and then discussed interaction of the flow transfixion with the heat transfixion, which has practical significance to projects. A numerical model of groundwater flow was established based on the basic tenets of water-heat transferring in the aquifer. On this basis the flow field and the temperature field of GSHPS for a site in Shenyang City were numerically simulated. The basis of the flow transfixion was obtained; it was discussed for the influence of the flow transfixion on the heat transfixion. To a certain extent, the study offers some reference for the projects' design of GSHP in the studied area.

  9. CO2 capture using fly ash from coal fired power plant and applications of CO2-captured fly ash as a mineral admixture for concrete.

    Science.gov (United States)

    Siriruang, Chaichan; Toochinda, Pisanu; Julnipitawong, Parnthep; Tangtermsirikul, Somnuk

    2016-04-01

    The utilization of fly ash as a solid sorbent material for CO2 capture via surface adsorption and carbonation reaction was evaluated as an economically feasible CO2 reduction technique. The results show that fly ash from a coal fired power plant can capture CO2 up to 304.7 μmol/g fly ash, consisting of 2.9 and 301.8 μmol/g fly ash via adsorption and carbonation, respectively. The CO2 adsorption conditions (temperature, pressure, and moisture) can affect CO2 capture performance of fly ash. The carbonation of CO2 with free CaO in fly ashes was evaluated and the results indicated that the reaction consumed most of free CaO in fly ash. The fly ashes after CO2 capture were further used for application as a mineral admixture for concrete. Properties such as water requirement, compressive strength, autoclave expansion, and carbonation depth of mortar and paste specimens using fly ash before and after CO2 capture were tested and compared with material standards. The results show that the expansion of mortar specimens using fly ash after CO2 capture was greatly reduced due to the reduction of free CaO content in the fly ash compared to the expansion of specimens using fresh fly ash. There were no significant differences in the water requirement and compressive strength of specimens using fly ash, before and after CO2 capture process. The results from this study can lead to an alternative CO2 capture technique with doubtless utilization of fly ash after CO2 capture as a mineral admixture for concrete. PMID:26803257

  10. Analysing Thermal Response Test Data Affected by Groundwater Flow and Surface Temperature Change

    Science.gov (United States)

    Verdoya, Massimo; Imitazione, Gianmario; Chiozzi, Paolo; Orsi, Marco; Armadillo, Egidio

    2014-05-01

    Tests that record the underground temperature variation due to a constant heat injected into a borehole (or extracted from it) by means of a carrier fluid are routinely performed to infer subsurface thermal conductivity and borehole thermal resistance, which are needed to size geothermal heat pump systems. The most popular model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). This model gives appropriate estimations of thermal parameters only if particular hydro-geological conditions are fulfilled. Several flaws can however affect data interpretation with ILS, which is based on strong assumptions like those of a purely conductive heat transfer regime in a homogeneous medium, no vertical heat flow and infinite length of the borehole. Other drawbacks can arise from the difficulty in the proper thermal insulation of the test equipment, and consequently with oscillations of the carrier fluid temperature due to surface temperature changes. In this paper, we focused on the treatment of thermal response test data when both advection and periodic changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under different hypothesis of Darcy velocity and thermal properties. A random noise was added to the signal in order to mimic high frequency disturbances, possibly caused by equipment operating conditions and/or geological variability. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by minimising the root mean square error between the synthetic dataset and the theoretical model. The optimisation was carried out with the Nelder-Mead algorithm, and thermal and hydraulic properties were determined by iterative reprocessing according to a trial-and-error procedure. The inferred thermal and hydraulic parameters are well consistent with the 'a priory' values, and the presence of noise in the synthetic data does not produce

  11. KINETICS OF FLY ASH BENEFICIATION BY CARBON BURNOUT; FINAL

    International Nuclear Information System (INIS)

    Surface area analyses performed on fly ash samples reveal that the surface area is controlled by carbon content. The higher surface areas found in large particles are due to the presence of highly porous carbonaceous particles. Adsorption-desorption isotherms and t-plots of fly ash samples indicate that fly ash is porous. BJH Adsorption/Desorption pore size analysis reveal that pore diameters are independent of sieve size. They appear to be dependent only on the nature of the material which confers porosity. Based on the results of Brown and Dykstra (41) it is reasonable to assume that calculations of reaction rates at temperatures above 550 C were confounded by weight losses from processes other than carbon oxidation and, therefore, are not useful in determination of the temperature dependence of carbon oxidation in fly ash. The results of the present study indicate that temperatures below 550 C should be used for future studies in order to satisfactorily assess the temperature dependence of carbon oxidation in fly ash. Furthermore, it is also advisable that percent carbon determinations be performed on fly ash samples after the oxidation reactions to determine whether all carbon present in fly ash is oxidized. This will ensure that reaction rates are representative of the complete oxidation of carbon. An inverse relationship was determined between reaction rates and oxygen concentration for this study. As discussed, this may be due to volatilization of volatiles from fly ash and ease of transport of products away from the reaction sites by the action of the vacuum applied to the samples. A more accurate determination of oxygen dependence of carbon oxidation can be accomplished by the use of specialty gases containing different concentrations of oxygen which could eliminate the need to apply vacuum to the samples

  12. KINETICS OF FLY ASH BENEFICIATION BY CARBON BURNOUT

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Joseph N.D. Dodoo; Dr. Joseph M. Okoh

    2000-11-01

    Surface area analyses performed on fly ash samples reveal that the surface area is controlled by carbon content. The higher surface areas found in large particles are due to the presence of highly porous carbonaceous particles. Adsorption-desorption isotherms and t-plots of fly ash samples indicate that fly ash is porous. BJH Adsorption/Desorption pore size analysis reveal that pore diameters are independent of sieve size. They appear to be dependent only on the nature of the material which confers porosity. Based on the results of Brown and Dykstra (41) it is reasonable to assume that calculations of reaction rates at temperatures above 550 C were confounded by weight losses from processes other than carbon oxidation and, therefore, are not useful in determination of the temperature dependence of carbon oxidation in fly ash. The results of the present study indicate that temperatures below 550 C should be used for future studies in order to satisfactorily assess the temperature dependence of carbon oxidation in fly ash. Furthermore, it is also advisable that percent carbon determinations be performed on fly ash samples after the oxidation reactions to determine whether all carbon present in fly ash is oxidized. This will ensure that reaction rates are representative of the complete oxidation of carbon. An inverse relationship was determined between reaction rates and oxygen concentration for this study. As discussed, this may be due to volatilization of volatiles from fly ash and ease of transport of products away from the reaction sites by the action of the vacuum applied to the samples. A more accurate determination of oxygen dependence of carbon oxidation can be accomplished by the use of specialty gases containing different concentrations of oxygen which could eliminate the need to apply vacuum to the samples.

  13. On the '-1' scaling of air temperature spectra in atmospheric surface layer flows

    Science.gov (United States)

    Li, D.; Katul, G. G.; Gentine, P.

    2015-12-01

    The spectral properties of scalar turbulence at high wavenumbers have been extensively studied in turbulent flows, and existing theories explaining the k-5/3 scaling within the inertial subrange appear satisfactory at high Reynolds numbers. Equivalent theories for the low wavenumber range have been comparatively lacking because boundary conditions prohibit attainment of such universal behavior. A number of atmospheric surface layer (ASL) experiments reported a k-1 scaling in air temperature spectra ETT(k) at low wavenumbers but other experiments did not. Here, the occurrence of a k-1 scaling in ETT(k) in an idealized ASL flow across a wide range of atmospheric stability regimes is investigated theoretically and experimentally. Experiments reveal a k-1 scaling persisted across different atmospheric stability parameter values (ζ) ranging from mildly unstable to mildly stable conditions (-0.1budget models and upon using a Heisenberg eddy viscosity as a closure to the spectral flux transfer term, conditions promoting a k-1 scaling are identified. Existence of a k-1 scaling is shown to be primarily linked to an imbalance between the production and dissipation rates of half the temperature variance. The role of the imbalance between the production and dissipation rates of half the temperature variance in controlling the existence of a '-1' scaling suggests that the '-1' scaling in ETT(k) does not necessarily concur with the '-1' scaling in the spectra of longitudinal velocity Euu(k). This finding explains why some ASL experiments reported k-1 in Euu(k) but not ETT(k). It also differs from prior arguments derived from directional-dimensional analysis that lead to simultaneous k-1 scaling in Euu(k) and ETT(k) at low wavenumbers in a neutral ASL.

  14. Flow and failure of an aluminium alloy from low to high temperature and strain rate

    Directory of Open Access Journals (Sweden)

    Sancho Rafael

    2015-01-01

    Full Text Available The mechanical behaviour of an aluminium alloy is presented in this paper. The study has been carried out to analyse the flow and failure of the aluminium alloy 7075-T73. An experimental study has been planned performing tests of un-notched and notched tensile specimens at low strain rates using a servo-hydraulic machine. High strain rate tests have been carried out using the same geometry in a Hopkinson Split Tensile Bar. The dynamic experiments at low temperature were performed using a cryogenic chamber, and the high temperature ones with a furnace, both incorporated to the Hopkinson bar. Testing temperatures ranged from − 50 ∘C to 100 ∘C and the strain rates from 10−4 s−1 to 600 s−1. The material behaviour was modelled using the Modified Johnson-Cook model and simulated using LS-DYNA. The results show that the Voce type of strain hardening is the most accurate for this material, while the traditional Johnson-Cook is not enough accurate to reproduce the necking of un-notched specimens. The failure criterion was obtained by means of the numerical simulations using the analysis of the stress triaxiality versus the strain to failure. The diameters at the failure time were measured using the images taken with an image camera, and the strain to failure was computed for un-notched and notched specimens. The numerical simulations show that the analysis of the evolution of the stress triaxiality is crucial to achieve accurate results. A material model using the Modified Johnson-Cook for flow and failure is proposed.

  15. Flow and failure of an aluminium alloy from low to high temperature and strain rate

    Science.gov (United States)

    Sancho, Rafael; Cendón, David; Gálvez, Francisco

    2015-09-01

    The mechanical behaviour of an aluminium alloy is presented in this paper. The study has been carried out to analyse the flow and failure of the aluminium alloy 7075-T73. An experimental study has been planned performing tests of un-notched and notched tensile specimens at low strain rates using a servo-hydraulic machine. High strain rate tests have been carried out using the same geometry in a Hopkinson Split Tensile Bar. The dynamic experiments at low temperature were performed using a cryogenic chamber, and the high temperature ones with a furnace, both incorporated to the Hopkinson bar. Testing temperatures ranged from - 50 ∘C to 100 ∘C and the strain rates from 10-4 s-1 to 600 s-1. The material behaviour was modelled using the Modified Johnson-Cook model and simulated using LS-DYNA. The results show that the Voce type of strain hardening is the most accurate for this material, while the traditional Johnson-Cook is not enough accurate to reproduce the necking of un-notched specimens. The failure criterion was obtained by means of the numerical simulations using the analysis of the stress triaxiality versus the strain to failure. The diameters at the failure time were measured using the images taken with an image camera, and the strain to failure was computed for un-notched and notched specimens. The numerical simulations show that the analysis of the evolution of the stress triaxiality is crucial to achieve accurate results. A material model using the Modified Johnson-Cook for flow and failure is proposed.

  16. Ash management in circulating fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    K. Redemann; E.-U. Hartge; J. Werther [Hamburg University of Technology, Hamburg (Germany). Institute of Solids Process Engineering and Particle Technology

    2008-12-15

    Ash management in fluidized bed combustion systems means keeping the particle size distribution of the bed inventory in a given range. A dynamic particle population balancing model was developed for this purpose. It was successfully applied to a refuse-derived fuel fired combustor and a coal-fired circulating fluidized bed combustor. Both were large-scale commercial units. The model uses the concept of the attrited ash particle size distribution which represents the particle size distribution of the attrited ash including the generated fines and replaces the consideration of the particle attrition in the model calculations. The model offers the possibility to gain additional information about the particle size distributions and the solids mass flows at any location of the fluidized bed system. In addition, the model provides information about the dynamic behavior of the plant and about mean residence times of particle size classes in the plant. Uncertainties about the ash formation characteristics of fuels make the management of the bed inventory a very important issue. In this context the population balancing model is used to predict the plant behavior under various operating conditions. The results of the calculations carried out give useful information about the possibilities to manage the ash inventory of such a plant. It could be shown that the recirculation of a fine fraction of the bottom drain solids is a very effective method to manage the particle size distribution of the bed inventory. The calculation results further reveal that the mean residence time of particles is strongly dependent on their size. 21 refs., 19 figs., 4 tabs.

  17. Modeling Temperature Development of Li-ion Battery Packs using Phase Change Materials (PCM) and Fluid Flow

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

    This paper presents a dynamic model for simulating the heat generation and the impact of Phase Change Materials (PCMs) on the maximum temperature in LiFePO4 battery cells. The model is constructed by coupling a one-dimensional electro-chemical model with a two-dimensional thermal model and fluid...... flow model in a battery pack array. Two different physics are analysed and compared, one when the heat equation is considered for the PCM (no-flow case) and another one when fluid flow is considered. The results show that by using PCMs, the maximum temperature drops considerably for both physics. The...

  18. Ashes for organic farming

    OpenAIRE

    Kousa, T.; Heinonen, M; Suoniitty, T.; Peltonen, K

    2013-01-01

    Nowadays only eight percent of the cultivated field area is used for organic farming. The Ministry of Agriculture and Forestry has published the guidelines for the program of organic farming to diversify the supply and the consumption of organic food. The aim is to increase organically arable land to 20% by the year 2020.The demand of organic fertilizer products is strongly increasing. Interest in forestry by-products (ash, bark, zero fiber, etc.) for use in organic production has recently be...

  19. Systematics of Water Temperature and Flow at Tantalus Creek During Calendar Year 2005, Norris Geyser Basin, Yellowstone National Park, Wyoming

    Science.gov (United States)

    Clor, Laura E.; Lowenstern, Jacob B.; Heasler, Henry P.

    2007-01-01

    We analyze data for stream flow and water temperature from Tantalus Creek in the Norris Geyser Basin and their relationship to air temperature, precipitation, and geyser eruptions during calendar year 2005. The creek is of interest because it is the primary drainage of the Norris Geyser Basin and carries a very high proportion of thermal water derived directly from hot springs. Two separate diurnal patterns emerge - (1) a winter pattern where increases in water temperature and stream flow closely track those of air temperature and (2) a summer pattern where water and air temperature are closely aligned but stream flow declines once water temperature reaches its daily maximum. The winter pattern is present when the daily average temperature consistently drops below 0 ?C whereas the summer pattern is recognizable when the daily average temperature regularly exceeds 0 ?C. Spring and fall systematics are much more irregular, although both summer and winter patterns can be discerned occasionally during those seasons. We interpret increases in stream flow associated with the winter pattern to result from addition of locally sourced melt water (both snow and soil-bound ice) that increases in abundance once temperatures increase in the morning. Melting is facilitated by the warm ground temperatures in the geyser basin, which are significantly higher than air temperatures in the winter. The summer pattern appears to be strongly affected by increased evaporation in the afternoon, decreasing flow and cooling the remaining water. Discharge from eruptions at Echinus Geyser are clearly visible as peaks in the hydrograph, and indicate that water from this geyser reach the Tantalus weir in 80 to 90 minutes, reflecting a slug of water that travels about 0.4 m s-1.

  20. Flickering characteristics and temperature field of premixed methane/air flame under the influence of co-flow

    International Nuclear Information System (INIS)

    Highlights: • Flickering characteristics and temperature field of premixed methane/air flame are studied in co-flow. • The temperature is measured by improved flame reaction technique by correcting the number density of metal atoms. • The temperature calibration is conducted by sodium D-line reversal method. • The oscillation amplitude of flame decreases and the frequency increases with co-flow velocity. • The oscillation amplitude increases with equivalence ratio. - Abstract: The flickering characteristics and the temperature field of an axisymmetric premixed methane/air flame under the influence of co-flow are studied experimentally using the image analysis and the flame reaction technique. The premixed flame is visualized by the alkali metal solution of sodium (Na) for characterizing the flickering characteristics. The temperature measurement of the flame is carried out using the flame reaction technique combined with the relationship between the local intensity of the flame and the temperature from the sodium D-line reversal method, and the influence of the number density distribution of Na on the measured temperature field is corrected by the measurement integrated analysis of the flame with the iterative procedure. This technique is validated by the local temperature measurement in the steady flame under the influence of co-flow using the thermocouple calibrated by the sodium D-line reversal method. The flame visualization and temperature measurement in the flickering flame of the premixed methane/air flame indicates that the flame contour and the temperature field oscillate periodically with the flickering frequency due to the Kelvin–Helmholtz instability of the flame. The oscillation amplitude decreases and the frequency increases gradually with the co-flow velocity increases similar to the observation in the diffusion flame in literature, while the oscillation amplitude grows with the equivalence ratio increases. These changes in the flickering

  1. Law of mixture used to model the flow behavior of a duplex stainless steel at high temperatures

    International Nuclear Information System (INIS)

    In this investigation the flow curves of a duplex stainless steel were drawn by performing hot compression tests over a wide temperature range of 950–1200 °C and strain rates of 0.001–100 s−1. The flow curves of ferrite and austenite phases in the duplex structure were depicted by conducting similar hot compression tests on two steels that were cast and prepared with the same chemical compositions. The flow curves of the austenitic steel were found typical of dynamic recrystallization. They were successfully modeled by using the experimental exponential equation proposed by Cingara and McQueen. The flow curves of the ferritic steel were typical of dynamic recovery. They were modeled by the dislocation density evolution function proposed by Estrin and Meckning. Comparing the flow curves of three studied steels, it was found that the flow curves of the duplex steel were very similar and close to those of the ferrite steel. It was understood that in a duplex structure of ferrite and austenite the flow behavior is mostly controlled by the softer phase, i.e. ferrite. The law of mixture was modified to consider the strain partitioning between ferrite and austenite. The distribution coefficients of ferrite and austenite were described and determined at different deformation conditions. The results of modeling satisfactorily predicted the experimental curves. It was shown that the influence of austenite on the flow behavior of the duplex structure is almost low. However, it increases as strain rate or temperature rises. - Highlights: ► Flow curves of austenite and ferrite in the duplex steel were modeled separately. ► The flow behavior of the duplex steel is mostly controlled by ferrite. ► The effect of austenite on flow curve increases with temperature and strain rate. ► The flow curve of the duplex steel is modeled by the modified law of mixture

  2. Heat exchange in a laminar channel flow with temperature gradients at the walls: possibility for heat transfer reversal

    Science.gov (United States)

    Sánchez, Manuel; Rebollo, Daniel; Campo, Antonio

    This paper presents a detailed numerical study of the heat exchange between two parallel plates with prescribed temperature gradients along the plates and a fluid circulating between them. The interplay between the bulk temperature, the heat flow and the Nusselt number has been clarified.

  3. Heat exchange in a laminar channel flow with temperature gradients at the walls: possibility for heat transfer reversal

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Manuel; Rebollo, Daniel [Instituto de Mecanica Aplicada, Universidad Nacional de San Juan, Libertador Gral. San Martin 1109 (oeste), 5400 San Juan (Argentina); Campo, Antonio [Department of Mechanical Engineering, The University of Vermont, VT 05405, Burlington (United States)

    2004-06-01

    This paper presents a detailed numerical study of the heat exchange between two parallel plates with prescribed temperature gradients along the plates and a fluid circulating between them. The interplay between the bulk temperature, the heat flow and the Nusselt number has been clarified. (orig.)

  4. Effect of temperature and associated bifurcation in the oscillatory Belousov—Zhabotinskii reaction in a flow reactor

    Science.gov (United States)

    Misra, G. P.

    1992-04-01

    Oscillatory characteristics of the Belousov—Zhabotinskii reaction as a function of temperature have been investigated in a continuous flow stirred tank reactor. Oscillations are not observed above a critical temperature limit. The limit is found to be associated with a Hopf bifurcation. Numerical computations show that the results can be qualitatively interpreted on the basis of the Oregonator model.

  5. Aerodynamic characteristics of popcorn ash particles

    Energy Technology Data Exchange (ETDEWEB)

    Cherkaduvasala, V.; Murphy, D.W.; Ban, H.; Harrison, K.E.; Monroe, L.S. [University of Alabama, Birmingham, AL (United States). Dept. of Mechanical Engineering

    2007-07-01

    Popcorn ash particles are fragments of sintered coal fly ash masses that resemble popcorn in low apparent density. They can travel with the flow in the furnace and settle on key places such as catalyst surfaces. Computational fluid dynamics (CFD) models are often used in the design process to prevent the carryover and settling of these particles on catalysts. Particle size, density, and drag coefficient are the most important aerodynamic parameters needed in CFD modeling of particle flow. The objective of this study was to experimentally determine particle size, shape, apparent density, and drag characteristics for popcorn ash particles from a coal-fired power plant. Particle size and shape were characterized by digital photography in three orthogonal directions and by computer image analysis. Particle apparent density was determined by volume and mass measurements. Particle terminal velocities in three directions were measured in water and each particle was also weighed in air and in water. The experimental data were analyzed and models were developed for equivalent sphere and equivalent ellipsoid with apparent density and drag coefficient distributions. The method developed in this study can be used to characterize the aerodynamic properties of popcorn-like particles.

  6. Mesoporous Silica from Rice Husk Ash

    OpenAIRE

    V.R. Shelke; S.S. Bhagade; S.A. Mandavgane

    2011-01-01

    Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as a concrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc. Sodium silicate is produced by reacting rice hull ash (RHA) with aqueous NaOH and silica is precipitated from the sodium silicate by acidification. In the present work, conversion of about 90% of silica contained in RHA into sodium silicate was achieved in an open system at temperatures...

  7. Ash Management Review—Applications of Biomass Bottom Ash

    Directory of Open Access Journals (Sweden)

    Harpuneet S. Ghuman

    2012-10-01

    Full Text Available In industrialized countries, it is expected that the future generation of bioenergy will be from the direct combustion of residues and wastes obtained from biomass. Bioenergy production using woody biomass is a fast developing application since this fuel source is considered to be carbon neutral. The harnessing of bioenergy from these sources produces residue in the form of ash. As the demand for bioenergy production increases, ash and residue volumes will increase. Major challenges will arise relating to the efficient management of these byproducts. The primary concerns for ash are its storage, disposal, use and the presence of unburned carbon. The continual increase in ash volume will result in decreased ash storage facilities (in cases of limited room for landfill expansion, as well as increased handling, transporting and spreading costs. The utilization of ash has been the focus of many studies, hence this review investigates the likely environmental and technological challenges that increased ash generation may cause. The presence of alkali metals, alkaline earth metals, chlorine, sulphur and silicon influences the reactivity and leaching to the inorganic phases which may have significant impacts on soils and the recycling of soil nutrient. Discussed are some of the existing technologies for the processing of ash. Unburned carbon present in ash allows for the exploration of using ash as a fuel. The paper proposes sieve fractionation as a suitable method for the separation of unburnt carbon present in bottom ash obtained from a fixed-bed combustion system, followed by the application of the gasification technology to particle sizes of energy importance. It is hoped that this process will significantly reduce the volume of ash disposed at landfills.

  8. Determination of the amplitude and phase relationships between oscillations in skin temperature and photoplethysmography-measured blood flow in fingertips

    International Nuclear Information System (INIS)

    It is well established that skin temperature oscillations in fingertips coexist with blood flow oscillations and there is a certain correlation between them. At the same time, the reasons for differences in waveform and the delay between the blood flow and temperature oscillations are far from being fully understood. In this study we determine the relationships between spectral components of the blood flow and temperature oscillations in fingertips, and we ascertain the frequency dependences of amplitude attenuation and delay time for the temperature oscillations. The blood flow oscillations were considered as a source of thermal waves propagating from micro-vessels towards the skin surface and manifesting as temperature oscillations. The finger temperature was measured by infrared thermography and blood flow was assessed by photoplethysmography for ten healthy subjects. The time–frequency analysis of oscillations was based on the Morlet wavelet transform. The frequency dependences of delay time and amplitude attenuation in temperature compared with blood flow oscillations have been determined in endothelial (0.005–0.02 Hz) and neurogenic (0.02–0.05 Hz) frequency bands using the wavelet spectra. We approximated the experimental frequency dependences by equations describing thermal wave propagation through the medium and taking into account the thermal properties and thickness of a tissue. Results of analysis show that with the increase of frequency f the delay time of temperature oscillations decreases inversely proportional to f1/2, and the attenuation of the amplitude increases directly proportional to exp f1/2. Using these relationships allows us to increase correlation between the processed temperature oscillations and blood flow oscillations from 0.2 to 0.7 within the frequency interval 0.005–0.05 Hz. The established experimental and theoretical relationships clarify an understanding of interrelation between the dynamics of blood flow and skin

  9. The effect of water temperature and synoptic winds on the development of surface flows over narrow, elongated water bodies

    Science.gov (United States)

    Segal, M.; Pielke, R. A.

    1985-01-01

    Simulations of the thermally induced breeze involved with a relatively narrow, elongated water body is presented in conjunction with evaluations of sensible heat fluxes in a stable marine atmospheric surface layer. The effect of the water surface temperature and of the large-scale synoptic winds on the development of surface flows over the water is examined. As implied by the sensible heat flux patterns, the simulation results reveal the following trends: (1) when the synoptic flow is absent or light, the induced surface breeze is not affected noticeably by a reduction of the water surface temperature; and (2) for stronger synoptic flow, the resultant surface flow may be significantly affected by the water surface temperature.

  10. Modeling of Air Temperature for Heat Exchange due to Vertical Turbulence and Horizontal Air Flow

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; MENG Qing-lin

    2009-01-01

    In order to calculate the air temperature of the near surface layer in urban environment,the Sur-face layer air was divided into several layers in the vertical direction,and some energy bakmce equations were de-veloped for each air layer,in which the heat exchange due to vertical turbulence and horizontal air flow was tak-en into account.Then,the vertical temperature distribution of the surface layer air was obtained through the coupled calculation using the energy balance equations of underlying surfaces and building walls.Moreover,the measured air temperatures in a small area (with a horizontal scale of less than 500 m) and a large area (with ahorizontal scale of more than 1000 m) in Guangzhou in summer were used to validate the proposed model.The calculated results agree well with the measured ones,with a maximum relative error of 4.18%.It is thus con-cluded that the proposed model is a high-accuracy method to theoretically analyze the urban heat island and the thermal environment.

  11. Sensitive biomolecule detection in lateral flow assay with a portable temperature-humidity control device.

    Science.gov (United States)

    Choi, Jane Ru; Hu, Jie; Feng, Shangsheng; Wan Abas, Wan Abu Bakar; Pingguan-Murphy, Belinda; Xu, Feng

    2016-05-15

    Lateral flow assays (LFAs) have currently attracted broad interest for point-of-care (POC) diagnostics, but their application has been restricted by poor quantification and limited sensitivity. While the former has been currently solved to some extent by the development of handheld or smartphone-based readers, the latter has not been addressed fully, particularly the potential influences of environmental conditions (e.g., temperature and relative humidity (RH)), which have not yet received serious attention. The present study reports the use of a portable temperature-humidity control device to provide an optimum environmental requirement for sensitivity improvement in LFAs, followed by quantification by using a smartphone. We found that a RH beyond 60% with temperatures of 55-60°C and 37-40°C produced optimum nucleic acid hybridization and antigen-antibody interaction in LFAs, respectively representing a 10-fold and 3-fold signal enhancement over ambient conditions (25°C, 60% RH). We envision that in the future the portable device could be coupled with a fully integrated paper-based sample-to-answer biosensor for sensitive detection of various target analytes in POC settings. PMID:26700582

  12. Operating parameters of liquid helium transfer lines used with continuous flow cryostats at low sample temperatures

    Science.gov (United States)

    Dittmar, N.; Welker, D.; Haberstroh, Ch; Hesse, U.; Krzyzowski, M.

    2015-12-01

    Continuous flow cryostats are used to cool samples to a variable temperature level by evaporating a cryogen, e.g. liquid helium (LHe). For this purpose LHe is usually stored outside the cryostat in a mobile dewar and supplied through a transfer line. In general, the complete setup has to be characterised by the lowest possible consumption of LHe. Additionally, a minimum sample temperature can be favourable from an experimental point of view. The achievement of both requirements is determined by the respective cryostat design as well as by the transfer line. In the presented work operating data, e.g. the LHe consumption during cooldown and steady state, the minimum sample temperature, and the outlet quality are analysed to characterise the performance of a reference transfer line. In addition, an experimental transfer line with built-in pressure sensors has been commissioned to examine the pressure drop along the transfer line, too. During the tests LHe impurities occurred which restricted a steady operation.

  13. Synthesis of merlinoite from Chinese coal fly ashes and its potential utilization as slow release K-fertilizer

    OpenAIRE

    Li, Jing; Zhuang, Xinguo; Font, Oriol; Moreno, Natalia; Vallejo, V. Ramón; Querol, Xavier; Tobias, Aurelio

    2014-01-01

    This study focuses on the synthesis of merlinoite from Chinese coal fly ashes by KOH direct conversion method, with special emphasis on the application of synthetic merlinoite as fertilizer. These fly ashes were collected from two pulverized-coal combustion (PCC) power plants in Xinjiang, Northwest China. The synthesis results are influenced by fly ash characteristics and different synthesis conditions (KOH solution concentrations, activation temperature, time, and KOH/fly ash ratios). A high...

  14. Using isotopic, hydrogeochemical-tracer and temperature data to characterize recharge and flow paths in a complex karst groundwater flow system in northern China

    Science.gov (United States)

    Sun, Ziyong; Ma, Rui; Wang, Yanxin; Ma, Teng; Liu, Yunde

    2016-04-01

    Isotopic and hydrogeochemical analysis, combined with temperature investigation, was conducted to characterize the flow system in the carbonate aquifer at Taiyuan, northern China. The previous division of karst subsystems in Taiyuan, i.e. the Xishan (XMK), Dongshan (DMK) and Beishan (BMK) mountain systems, were also examined. The measured δD, δ 18O and 3He/4He in water indicate that both thermal and cold groundwaters have a meteoric origin rather than deep crustal origin. Age dating using 3H and 14C shows that groundwater samples from discharge zones along faults located at the margin of mountains in the XMK and DMK are a mixture of paleometeoric thermal waters and younger cold waters from local flow systems. 14C data suggest that the average age was about 10,000 years and 4,000 years for thermal and cold groundwater in discharge zones, respectively. Based on the data of temperature, water solute chemical properties, 14C, δ 34SSO4, 87Sr/86Sr and δ 18O, different flow paths in the XMK and DMK were distinguished. Shallow groundwater passes through the upper Ordovician formations, producing younger waters at the discharge zone (low temperature and ionic concentration and enriched D and 18O). Deep groundwater flows through the lower Ordovician and Cambrian formations, producing older waters at the discharge zone (high ionic concentration and temperature and depleted D and 18O). At the margin of mountains, groundwater in deep systems flows vertically up along faults and mixes with groundwater from shallow flow systems. By contrast, only a single flow system through the entire Cambrian to Ordovician formations occurs in the BMK.

  15. INF 325 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    SINDHU

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com INF 325 Week 1 DQ 1 Network Management (Ash) INF 325 Week 1 DQ 2 Ethernet Network (Ash) INF 325 Week 1 Commercial Internet Expansion (Ash) INF 325 Week 2 DQ 1 UTP Cord Problem (Ash) INF 325 Week 2 DQ 2 Managed Switches (Ash) INF 325 Week 2 Leased Lines (Ash) INF 325 Week 3 DQ 1 WPA (Ash) INF 325 Week 3 DQ 2 Remote Access Management (Ash) INF 325 Week 3 Mobile Service (Ash) INF 325 Week 4 DQ 1 Ro...

  16. INF 336 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    MADURA

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com INF 336 Week 1 DQ 1 Risk Management (Ash) INF 336 Week 1 DQ 2 Organizational Structure (Ash) INF 336 Week 2 DQ 1 Supply Process Improvements (Ash) INF 336 Week 2 DQ 2 Outsourcing (Ash) INF 336 Week 2 Assignment Article Review (Ash) INF 336 Week 3 DQ 1 Capital Goods (Ash) INF 336 Week 3 DQ 2 Quality (Ash) INF 336 Week 3 Assignment Need Definition (Ash) INF 336 Week 4 DQ 1 Procuring Services (Ash) ...

  17. MGT 401 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    kennith

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MGT 401 Week 1 Individual Assignment Strategic Management Process Paper (Ash) MGT 401 Week 1 Class Activity Week 1 (Ash) MGT 401 Week 1 DQ 1 (Ash) MGT 401 Week 1 DQ 2 (Ash) MGT 401 Week 2 Learning Team Business Model Comparison Example (Ash) MGT 401 Week 2 DQ 1 (Ash) MGT 401 Week 2 DQ 2 (Ash) MGT 401 Week 2 Class Activity (Ash) MGT 401 Week 3 Individual Assignment Business Plan Evaluation (Ash) ...

  18. INF 410 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    MADHURA

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com     INF 410 Week 1 DQ 1 Project Life Cycle (Ash) INF 410 Week 1 DQ 2 The Importance of Project Management (Ash) INF 410 Week 1 Quiz (Ash) INF 410 Week 2 DQ 1 Project Charter (Ash) INF 410 Week 2 DQ 2 Project Management Plan (Ash) INF 410 Week 2 Quiz (Ash) INF 410 Week 3 DQ 1 Risk Identification (Ash) INF 410 Week 3 DQ 2 Triple Constraint (Ash) INF 410 Week 3 Quiz (Ash) INF 410 Week 4 DQ...

  19. Characterization and possible uses of ashes from wastewater treatment plants

    International Nuclear Information System (INIS)

    This work, on the ashes from the wastewater treatment plant of Galindo (Vizcaya, Spain), has been outlined with the purpose of finding their physico-chemical properties and suggesting possible applications. Ashes contain important quantities of iron, calcium, silica, alumina and phosphates. X-Ray diffraction data make it possible to estimate the mineralogical compositions of the original ashes and also, after thermal treatment at 1200 and 1300 deg. C, the main reactions occurring in thermal treatment. Particle size analysis makes it possible to classify ashes as a very fine powdered material. The thermal treatment leads to a densification of the material and provokes losses of weight mainly due to the elimination of water, carbon dioxide and sulphur trioxide. Application tests show that ashes are not suitable for landfill and similar applications, because of their plastic properties. Testing for pozzolanic character, after the ashes had been heated at 1200 deg. C, did not lead to a strong material probably due to low contents in silica and alumina or to requiring a higher heating temperature. Thermal treatment leads to densification of the material with a considerable increase of compressive strength of the probes. The use of additives (clays and powdered glass) to improve ceramic properties of ashes will be the aim of a future work

  20. Wellbore and groundwater temperature distribution eastern Snake River Plain, Idaho: Implications for groundwater flow and geothermal potential

    Energy Technology Data Exchange (ETDEWEB)

    McLing, Travis L.; Smith, Richard P.; Smith, Robert W.; Blackwell, David D.; Roback, Robert C.; Sondrup, Andrus J.

    2016-06-01

    A map of groundwater temperatures from the Eastern Snake River Plain (ESRP) regional aquifer can be used to identify and interpret important features of the aquifer, including aquifer flow direction, aquifer thickness, and potential geothermal anomalies. The ESRP is an area of high heat flow, yet most of this thermal energy fails to reach the surface, due to the heat being swept downgradient by the aquifer to the major spring complexes near Thousand Springs, ID, a distance of 300 km. Nine deep boreholes that fully penetrate the regional aquifer display three common features: (1) high thermal gradients beneath the aquifer, corresponding to high conductive heat flow in low-permeability hydrothermally-altered rocks; (2) isothermal temperature profiles within the aquifer, characteristic of an actively flowing groundwater; and (3) moderate thermal gradients in the vadose zone with values that indicate that over half of the geothermal heat flow is removed by advective transport in the regional aquifer system. This study utilized temperature data from 250 ESRP aquifer wells to evaluate regional aquifer flow direction, aquifer thickness, and potential geothermal anomalies. Because the thermal gradients are typically low in the aquifer, any measurement of groundwater temperature is a reasonable estimate of temperature throughout the aquifer thickness, allowing the construction of a regional aquifer temperature map for the ESRP. Mapped temperatures are used to identify cold thermal plumes associated with recharge from tributary valleys and adjacent uplands, and warm zones associated with geothermal input to the aquifer. Warm zones in the aquifer can have various causes, including local circulation of groundwater through the deep conductively dominated region, slow groundwater movement in low-permeability regions, or localized heat flow from deeper thermal features.

  1. The ash in forest fire affected soils control the soil losses. Part 2. Current and future research challenges

    Science.gov (United States)

    Pereira, Paulo; Cerdà, Artemi

    2013-04-01

    Ash distribution on soil surface and impacts on soil properties received a great attention in recently (Pereira et al., 2010; Pereira et al., 2013). Ash it is a highly mobile material that can be easily transported wind, especially in severe wildland fires, where organic matter is reduced to dust, due the high temperatures of combustion. In the immediate period after the fire, ash cover rules soil erosion as previous researchers observed (Cerdà, 1998a; 1998b) and have strong influence on soil hydrological properties, such as water retention (Stoof et al. 2011 ) and wettability (Bodi et al., 2011). Ash it is also a valuable source of nutrients important for plant recuperation (Pereira et al., 2011; Pereira et al., 2012), but can act also as a source contamination, since are also rich in heavy metals (Pereira and Ubeda, 2010). Ash has different physical and chemical properties according the temperature of combustion, burned specie and time of exposition (Pereira et al., 2010). Thus this different properties will have different implications on soil properties including erosion that can increase due soil sealing (Onda et al. 2008) or decrease as consequence of raindrop impact reduction (Cerdà and Doerr, 2008). The current knowledge shows that ash has different impacts on soil properties and this depends not only from the type of ash produced, but of the soil properties (Woods and Balfour, 2010). After fire wind and water strong redistribute ash on soil surface, increasing the vulnerability of soil erosion in some areas, and reducing in others. Understand this mobility is fundamental have a better comprehension about the spatial and temporal effects of ash in soil erosion. Have a better knowledge about this mobility is a priority to future research. Other important aspects to have to be assessed in the future are how ash particulates percolate on soil and how ash chemical composition is important to induce soil aggregation and dispersion. How soil micro topography

  2. Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression

    International Nuclear Information System (INIS)

    Supercritical carbon dioxide (scCO2) is often used to replace harmful solvents and can dissolve a wide range of organic compounds. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO2 is fairly accessible. Because of the compressible nature of scCO2 and the large changes of viscosity and density with temperature and pressure, there is a need to determine the behavior of scCO2 in microfluidic systems. Here, the influence of how parameters such as flow rate, temperature, pressure, and flow ratio affects the length of parallel flow of water and scCO2 and the length of the created CO2 segments are investigated and modeled using multivariate data analysis for a 10 mm long double-y channel. The parallel length and segment size were observed in the laminar regime around and above the critical point of CO2. The flow ratio between the two fluids together with the flow rate influenced both the parallel length and the segment sizes, and a higher pressure resulted in shorter parallel lengths. Regarding the segment length of CO2, longer segments were a result of a higher Weber number for H2O together with a higher temperature in the channel. (paper)

  3. Computational thermal-fluid dynamics analysis of the laminar flow regime in the meander flow geometry characterizing the heat exchanger used in high temperature superconducting current leads

    International Nuclear Information System (INIS)

    Highlights: • The laminar regime in the meander flow geometry has been analysed with a previously validated computational strategy. • Several meander flow geometries as well as flow conditions have been analysed. • A range for the Reynolds number has been defined in which the flow can be considered laminar. • Correlations for the pressure drop and the heat transfer coefficients in the laminar regime have been derived. • A comparison between the computed the experimental pressure drop of the W7-X HTS current lead prototype is presented. -- Abstract: The Karlsruhe Institute of Technology and the Politecnico di Torino have developed and validated a computational thermal-fluid dynamics (CtFD) strategy for the systematic analysis of the thermal-hydraulics inside the meander flow heat exchanger used in high-temperature superconducting current leads for fusion applications. In the recent past, the application of this CtFD technique has shown that some operating conditions occurring in these devices may not reach the turbulent regime region. With that motivation, the CtFD analysis of the helium thermal-fluid dynamics inside different meander flow geometries is extended here to the laminar flow regime. Our first aim is to clarify under which operative conditions the flow regime can be considered laminar and how the pressure drop as well as the heat transfer are related to the geometrical parameters and to the flow conditions. From the results of this analysis, correlations for the pressure drop and for the heat transfer coefficient in the meander flow geometry have been derived, which are applicable with good accuracy to the design of meander flow heat exchangers over a broad range of geometrical parameters

  4. Electrodialytic treatment of fly ash

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Pedersen, Anne Juul; Kirkelund, Gunvor Marie;

    Heavy metals are removed from the fly ashes by an electrodialytic treatment with the aim of up-grading the ashes for reuse in stead of disposal in landfill.A great potential for upgrading of bio- and waste incineration ashes by electrodialytic treatment exists. In the future, the applicability of...... the treated products for reuse in construction or farming sectors should be explored further, as should the possibility of recycling of valuable, extracted elements in the metallurgical industry....

  5. Using water chemistry, isotopes and microbiology to evaluate groundwater sources, flow paths and geochemical reactions in the Death Valley flow system, USA

    International Nuclear Information System (INIS)

    Springs of Ash Meadows and Furnace Creek (near or in Death Valley, CA) have nearly constant flow, temperature, chemistry, and similar δ2H and δ18O signatures. These factors indicate shared water sources and/or analogous geochemical reactions along similar flow paths. DNA-based (16S rRNA gene) microbial diversity assessments further illuminate these relationships. Whereas, all Ash Meadows springs share related archaea populations, variations in carbon-14 (Crystal Spring) and strontium isotopes, Na+, SO42-, and methane concentrations (Big Spring), correspond with microbial differences within and between the two discharge areas. Similar geochemical signatures linking Ash Meadows and Furnace Creek springs appear to support a distinct end member at Big Spring in Ash Meadows, which is also supported by coincident enrichment in microbial methanogens and methanotrophs. Conversely, DNA libraries from a deep carbonate well (878 m) located between Ash Meadows and Furnace Creek (BLM-1), indicate no shared microbial diversity between Ash Meadows or Furnace Creek springs. (authors)

  6. Using water chemistry, isotopes and microbiology to evaluate groundwater sources, flow paths and geochemical reactions in the Death Valley flow system, USA

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, James M.; Hershey, Ronald L. [Desert Research Institute, 2215 Raggio Pwky, Reno, NV, USA 89512 (United States); Moser, Duane P.; Fisher, Jenny C.; Reihle, Jessica; Wheatley, Alexandra [Desert Research Institute, 755 E. Flamingo Rd, Las Vegas, NV, USA 89130 (United States); Baldino, Cristi; Weissenfluh, Darrick [US Fish and Wildlife Service, Ash Meadows NWR, Amargosa Valley, NV, USA 89020 (United States)

    2013-07-01

    Springs of Ash Meadows and Furnace Creek (near or in Death Valley, CA) have nearly constant flow, temperature, chemistry, and similar δ{sup 2}H and δ{sup 18}O signatures. These factors indicate shared water sources and/or analogous geochemical reactions along similar flow paths. DNA-based (16S rRNA gene) microbial diversity assessments further illuminate these relationships. Whereas, all Ash Meadows springs share related archaea populations, variations in carbon-14 (Crystal Spring) and strontium isotopes, Na{sup +}, SO{sub 4}{sup 2-}, and methane concentrations (Big Spring), correspond with microbial differences within and between the two discharge areas. Similar geochemical signatures linking Ash Meadows and Furnace Creek springs appear to support a distinct end member at Big Spring in Ash Meadows, which is also supported by coincident enrichment in microbial methanogens and methanotrophs. Conversely, DNA libraries from a deep carbonate well (878 m) located between Ash Meadows and Furnace Creek (BLM-1), indicate no shared microbial diversity between Ash Meadows or Furnace Creek springs. (authors)

  7. Anomalous Flux-Flow Dynamics in Layered Type-II Superconductors at Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Feigelman, M.; Skvortsov, M. [L.D. Landau Institute for Theoretical Physics, Moscow 117940 (Russia)

    1997-03-01

    Low-temperature dissipation due to vortex motion in strongly anisotropic type-II superconductors with a moderate disorder ({Delta}{sup 2}/E{sub F}{lt}{h_bar}/{tau} {lt}{Delta}) is shown to be determined by the Zener-type transitions between the localized electronic states in the vortex core. Statistics of these levels is described by the random matrix ensemble of class C defined recently by Atland and Zirnbauer, so the vortex motion leads naturally to a new example of a parametric statistics of energy levels. The flux-flow conductivity {sigma}{sub xx} is a bit lower than the quasiclassical one and {ital grows} slowly with the increase of the electric field. {copyright} {ital 1997} {ital The American Physical Society}

  8. Radiative, two-temperature simulations of low luminosity black hole accretion flows in general relativity

    CERN Document Server

    Sadowski, A; Narayan, R; Abarca, D; McKinney, J C

    2016-01-01

    We present a numerical method which evolves a two-temperature, magnetized, radiative, accretion flow around a black hole, within the framework of general relativistic radiation magnetohydrodynamics. As implemented in the code KORAL, the gas consists of two sub-components -- ions and electrons -- which share the same dynamics but experience independent, relativistically consistent, thermodynamical evolution. The electrons and ions are heated independently according to a standard prescription from the literature for magnetohydrodynamical turbulent dissipation. Energy exchange between the particle species via Coulomb collisions is included. In addition, electrons gain and lose energy and momentum by absorbing and emitting synchrotron and bremsstrahlung radiation, and through Compton scattering. All evolution equations are handled within a fully covariant framework in the relativistic fixed-metric spacetime of the black hole. Numerical results are presented for five models of low luminosity black hole accretion. ...

  9. Development of construction materials using coal fly-ash

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moon Young; Yoo, Jang Han; Lee, Moo Sung [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-12-01

    The research is intended to find out the possibilities for utility of building materials such as brick with various mixtures of the kaolin and clay. The kaolin belong to the PD, PC and WC grades which from the fly ash of the Honam and the Samcheonpo thermal power plants and clay (HD) from the Hwangdeung, Hadong and Sancheong areas. 1) -200 mesh grain size of fly ash shows higher alkali contents than +200 mesh grains. Especially, alkali components such as CaO (10.58 %), MgO (1.67 %) and Na{sub 2}O (0.53 %) have contributed to make dense structure because of the alkalis are fusion materials. For example, 50 % mixture ratio of fly ash and clay shows the compressional strength of 1,700 kg/cm{sup 2}. The higher mixture ratio of fly ash and clay, the higher compressional intensity is found in general. 2) As the result of the reaction between CaO and Na{sub 2}O compositions in the Honam fly ash, and SiO{sub 2} and Al{sub 2}O{sub 3} in clay at the 1,200 deg. C has shown the formation of plagioclase crystal. 3) Fly ash in the Samcheonpo thermal power plants has lower contents of alkali component than the fly ash in the Honam. If the mixture ratio of fly ash is 10 % the compressional strength is found to be 600-720 kg/cm{sup 2}, that is because of the higher concentrations of uncombustible carbon in the Samcheonpo plant. The compressional intensity decreases as the fly ash contents are increased. When the ratio of mixture in the fly ash is 50 %, the compressional intensity shows 270-300 kg/cm{sup 2}. 4) Mixture experiments among PD, PC and WC grades of kaolin, the sintering has not formed in the grains at the 1,200 deg. C and the compressional strength is rather low with 60{approx}125 kg/cm{sup 2}. At the temperature of sintering is 1250 deg. C the sintering in the grains has been taken place with 210 kg/cm{sup 2}. But the temperature of 1,300 deg. C, the surface of sintering materials shows cracks. 5) The possibilities for usage of fly ash to develop the bricks with various

  10. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    Energy Technology Data Exchange (ETDEWEB)

    Danko, G.; Birkholzer, J.T.; Bahrami, D.; Halecky, N.

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  11. The temperature dependence of the flow stress of 600-MeV proton irradiated aluminium

    International Nuclear Information System (INIS)

    Tensile tests were performed on aluminium foils of 0.1 mm thickness that had been irradiated in the PIREX facility in the cyclotron of the Swiss Nuclear Research Institute (SIN) at doses between 0.9 to 5 dpa. Helium is produced at a measured rate of 230 appm/dpa simultaneously with the displacement damage. The post irradiation tests were performed in the range from 190 to 470 K. An increase of a factor four in the flow stress is found in the irradiated material at a dose 4.1 dpa at 190 K. The increase in flow stress is found to be proportional to the square root of the dose at all test temperatures. This increase has no clear correlation with bubble structure observed by TEM (either with bubble size or number density). These measurements, together with those of activation volume and TEM in-situ deformation, indicate that the main obstacle to dislocation glide is the presence of a dispersion of small (∝1 nm diameter) clusters of impurities produced by spallation reactions during the irradiation. A modified Fleischer hardening model is used to describe the results. Good agreement with experimental data is found for a dislocation escape of 1400, which corresponds to the angle measured during the TEM in-situ deformations. (orig.)

  12. Classification of pulverized coal ash

    International Nuclear Information System (INIS)

    The leachability of fifty different pulverized coal ashes from utilities in the Netherlands, Federal Republic of Germany and Belgium has been studied. Five different ashes were analyzed according to the complete standard leaching test and the results were published earlier. The examination of a wide variety of ashes under a wide range of pH and Liquid to Solid ratio (LS) conditions creates the possibility of identifying systematic trends in fly ash leaching behaviour and to identify the mechanisms controlling release. 16 figs., 2 tabs., 3 app., 25 refs

  13. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    produced ash has significant and not always constructive pedological, ecological, hydrological and geomorphological effects and impacts (Shakesby, 2011). Abundant scientific information is assembled either from control fires by collecting samples before and after wildfire event, or conducting laboratory experiments exanimating data under truly isolated conditions (Lugassi et al., 2013). However, an integration and synthesis of the knowledge about ash including deeper understanding of inter-correlation between chemical, physical and morphological compounds in open post-burn environment and its possible interactions in soil formation or impact on soil composition are highly needed. The main aim of the presented study was to advance the science of soil-fire relationship by recognizing the remains ash as a new soil-forming factor, on par with the traditionally recognized factors: parent material, topography, time, climate, organisms, and recently recognized human activity as the sixth factor. This research was conducted to develop new methods to assess impacts and quantify the contributions/influences of post-fire products, mainly ash, on soil composition and soil properties in post-burned environment. We conducted several controlled experiments using 40 soil samples (typical Mediterranean Rendzina soil, pH 6.84, a grayish-brown, humus- and free calcium carbonate- rich, intra-zonal). The samples include bare soils and different types and loads of forest litter, were exposed to different temperatures (200° C, 400° C and 600° C) in a muffle furnace for 2 hours (Pereira et al. 2011) as fire temperature plays a key role in determining ash properties. The ash produced at a low temperatures (50% carbon and retains many of the structural characteristics of the parent material. At higher temperatures, the residue ash is greyish, consisted of very fine particles that preserve almost none of the original structural characteristics of the fuel (Woods and Balfour, 2008) creating

  14. Full-scale ash deposition measurements at Avedøre Power Plant unit 2 during suspension-firing of wood with and without coal ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

    The formation of deposits during suspension-firing of wood at Avedøre Power Plant unit 2 (AVV2) was studied by using an advanced deposit probe system. The tests were conducted both with and without coal ash addition, and at two different locations with flue gas temperatures of 1250-1300 oC and 750...... along with the fly ash and bottom ash from the plant were characterized extensively by SEM-EDS, ICP-OES/IC and XRD. Based on the results from the present work, the deposit formation and shedding mechanisms under different operational conditions were proposed and discussed. The influence of coal ash...... addition on deposit formation during wood suspension-firing at AVV2 was evaluated. It was revealed that the addition of coal fly ash could significantly influence the ash deposition/shedding behaviors and the deposit properties. The effect was evident at both measurement locations. At the location...

  15. Analysis of riverbed temperatures to determine the geometry of subsurface water flow around in-stream geomorphological structures

    Science.gov (United States)

    Munz, Matthias; Oswald, Sascha E.; Schmidt, Christian

    2016-08-01

    The analytical evaluation of diurnal temperature variation in riverbed sediments provides detailed information on exchange fluxes between rivers and groundwater. The underlying assumption of the stationary, one-dimensional vertical flow field is frequently violated in natural systems where subsurface water flow often has a significant horizontal component. In this paper, we present a new methodology for identifying the geometry of the subsurface flow field using vertical temperature profiles. The statistical analyses are based on model optimisation and selection and are used to evaluate the shape of vertical amplitude ratio profiles. The method was applied to multiple profiles measured around in-stream geomorphological structures in a losing reach of a gravel bed river. The predominant subsurface flow field was systematically categorised in purely vertical and horizontal (hyporheic, parafluvial) components. The results highlight that river groundwater exchange flux at the head, crest and tail of geomorphological structures significantly deviated from the one-dimensional vertical flow, due to a significant horizontal component. The geometry of the subsurface water flow depended on the position around the geomorphological structures and on the river level. The methodology presented in this paper features great potential for characterising the spatial patterns and temporal dynamics of complex subsurface flow geometries by using measured temperature time series in vertical profiles.

  16. Heat and momentum transfer in a gas coolant flow through a circular pipe in a high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    In Japan Atomic Energy Research Institute (JAERI), a very high temperature gas cooled reactor (VHTR) has been researched and developed with a purpose of attaining a coolant temperature of around 1000degC at the reactor outlet. In order to design VHTR, comprehensive knowledge is required on thermo-hydraulic characteristics of laminar-turbulent transition, of coolant flow with large thermal property variation due to temperature difference, and of heat transfer deterioration. In the present investigation, experimental and analytical studies are made on a gas flow in a circular tube to elucidate the thermo-hydraulic characteristics. Friction factors and heat transfer coefficients in transitional flows are obtained. Influence of thermal property variation on the friction factor is qualitatively determined. Heat transfer deterioration in the turbulent flow subjected to intense heating is experimentally found to be caused by flow laminarization. The analysis based on a k-kL two-equation model of turbulence predicts well the experimental results on friction factors and heat transfer coefficients in flows with thermal property variation and in laminarizing flows. (author)

  17. Increasing synchrony of high temperature and low flow in western North American streams: double trouble for coldwater biota?

    Science.gov (United States)

    Arismendi, Ivan; Safeeq, Mohammad; Johnson, Sherri L.; Dunham, Jason B.; Haggerty, Roy

    2013-01-01

    Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and decreases in low flow during summer/fall have been reported. We hypothesized that an earlier peak flow could be shifting the timing of low flow and leading to a decrease in the interval between Tmax_w and Qmin. We also examined if years with extreme low Qmin were associated with years of extreme high Tmax_w. We tested these hypotheses using long32 term data from 22 minimally human-influenced streams for the period 1950-2010. We found trends toward a shorter time lag between Tmax_w and Qmin over time and a strong negative association between their magnitudes. Our findings show that aquatic biota may be increasingly experiencing narrower time windows to recover or adapt between these extreme events of low flow and high temperature. This study highlights the importance of evaluating multiple environmental drivers to better gauge the effects of the recent climate variability in freshwaters.

  18. Flow Rates Measurement and Uncertainty Analysis in Multiple-Zone Water-Injection Wells from Fluid Temperature Profiles

    Directory of Open Access Journals (Sweden)

    José E. O. Reges

    2016-07-01

    Full Text Available This work is a contribution to the development of flow sensors in the oil and gas industry. It presents a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, a method to iteratively calculate the zonal flow rates using the Ramey (exponential model was described. Next, this model was linearized to perform an uncertainty analysis. Then, a computer program to calculate the injected flow rates from experimental temperature profiles was developed. In the experimental part, a fluid temperature profile from a dual-zone water-injection well located in the Northeast Brazilian region was collected. Thus, calculated and measured flow rates were compared. The results proved that linearization error is negligible for practical purposes and the relative uncertainty increases as the flow rate decreases. The calculated values from both the Ramey and linear models were very close to the measured flow rates, presenting a difference of only 4.58 m³/d and 2.38 m³/d, respectively. Finally, the measurement uncertainties from the Ramey and linear models were equal to 1.22% and 1.40% (for injection zone 1; 10.47% and 9.88% (for injection zone 2. Therefore, the methodology was successfully validated and all objectives of this work were achieved.

  19. Flow Rates Measurement and Uncertainty Analysis in Multiple-Zone Water-Injection Wells from Fluid Temperature Profiles.

    Science.gov (United States)

    Reges, José E O; Salazar, A O; Maitelli, Carla W S P; Carvalho, Lucas G; Britto, Ursula J B

    2016-01-01

    This work is a contribution to the development of flow sensors in the oil and gas industry. It presents a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, a method to iteratively calculate the zonal flow rates using the Ramey (exponential) model was described. Next, this model was linearized to perform an uncertainty analysis. Then, a computer program to calculate the injected flow rates from experimental temperature profiles was developed. In the experimental part, a fluid temperature profile from a dual-zone water-injection well located in the Northeast Brazilian region was collected. Thus, calculated and measured flow rates were compared. The results proved that linearization error is negligible for practical purposes and the relative uncertainty increases as the flow rate decreases. The calculated values from both the Ramey and linear models were very close to the measured flow rates, presenting a difference of only 4.58 m³/d and 2.38 m³/d, respectively. Finally, the measurement uncertainties from the Ramey and linear models were equal to 1.22% and 1.40% (for injection zone 1); 10.47% and 9.88% (for injection zone 2). Therefore, the methodology was successfully validated and all objectives of this work were achieved. PMID:27420068

  20. Can pore-clogging by ash explain post-fire runoff?

    NARCIS (Netherlands)

    Stoof, Cathelijne R.; Gevaert, Anouk I.; Baver, Christine; Hassanpour, Bahareh; Morales, Verónica L.; Zhang, Wei; Martin, Deborah; Giri, Shree K.; Steenhuis, Tammo S.

    2016-01-01

    Ash plays an important role in controlling runoff and erosion processes after wildfire and has frequently been hypothesised to clog soil pores and reduce infiltration. Yet evidence for clogging is incomplete, as research has focussed on identifying the presence of ash in soil; the actual flow pro

  1. Influence of feed and sampling systems on element partitioning in Kentucky fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Valentim, Bruno V. [Centro e Departamento de Geologia Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto (Portugal); Hower, James C. [University of Kentucky Center for Applied Energy Research (CAER), Lexington, Kentucky, 40511 (United States)

    2010-05-01

    Pentannual surveys of the production of coal combustion byproducts in Kentucky utility power plants, along with other studies in the intervening years has resulted in a large amount of data relating coal chemistry, fly ash (FA) chemistry, and, to a lesser degree, bottom ash chemistry. Therefore, this important collection of data enables to perform studies on a wide variety of fly ash types. The chemical classification, based on major oxides (acid, alkaline, and Fe{sub 2}O{sub 3}), of coal high-temperature ash (HTA) and FA from Kentucky Power Plants shows that the majority of the coal HTAs are Sialic, Sialic-Ferrisialic, and Ferrisialic. The FA classification not only depends of the coal HTA chemistry but also the ash-collection system and the sampling position, with the implications of flue gas temperature and ash particle size, within the system. (author)

  2. Probe Measurements of Ash Deposit Formation Rate and Shedding in a Biomass Suspension-Fired boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming;

    The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension-fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share in...... wood), probe exposure time, probe surface temperature (500, 550 and 600 oC) and flue gas temperature (600 - 1050 oC) on ash deposit formation rate, heat uptake by the probe, the fly ash and deposit characteristics, and deposit removal have been investigated. The results indicated that increase in flue...... video recordings of all deposit probe experiments revealed that deposit shedding was primarily through debonding from the surface of the tubes in the superheater region. Chemical analysis of fly ashes indicated that during suspension-firing of straw and wood, the fly ashes were rich in Si, K, Ca and Cl...

  3. Incident energy dependence of the mean kinetic energy, flow and temperature azimuthal distributions

    International Nuclear Information System (INIS)

    The squeeze-out phenomena initially predicted by hydrodynamical calculations has been extensively studied experimentally. A unified representation of the observed trends can be done in terms of the azimuthal distribution of the total mass or kinetic energy. Previously reported comprehensive description of the squeeze-out phenomena in the range 0.25 - 1.15 A · GeV was based on the parametrization of the total mass spectra with an expression characteristic for radially symmetric shell expansion. As far as such a situation can hardly be encountered in heavy ion collisions and is not specific at all for mid-central geometries, we prefer to present also the experimental information free of any model which can be used to extract it. Due to this reasons we report also the results on azimuthal distribution of the mean kinetic energy (kincm>) besides the ones corresponding to β and T values. The azimuthal distributions of kincm>, β and T can be fit with the following expression: (kincm>, β,T) = (kincm>, β,T)0 - (Δ kincm>, Δβ, ΔT) ·cos2Φ. The excitation functions of (kincm>, β,T)max and (kincm>, β,T)min from 90 A · MeV to 400 A · MeV are given. The ellipsoidal character of the flow with the major axis perpendicular to the reaction plane constantly enhances from 90 to 400 A· MeV. At 90 A · MeV the two values are very similar. The lower slope in (E,β,T)min is due to the fact that the violence of the expansion increases faster as a function of incident energy than the decrease of the passage time. At higher incident energy the relativistic contraction and the gradient of the thermal pressure in the reaction plane due to the confinement created by the spectator matter are increasing. The two slopes reverse and a crossing point is expected. It would correspond to an elliptic flow with the major axis aligned in the reaction plane. A larger modulation in the mean kinetic energy or flow relative to temperature can be explained by the larger variation of the

  4. Thermal treatment and vitrification of boiler ash from a municipal solid waste incinerator.

    Science.gov (United States)

    Yang, Y; Xiao, Y; Voncken, J H L; Wilson, N

    2008-06-15

    Boiler ash generated from municipal solid waste (MSW) incinerators is usually classified as hazardous materials and requires special disposal. In the present study, the boiler ash was characterized for the chemical compositions, morphology and microstructure. The thermal chemical behavior during ash heating was investigated with thermal balance. Vitrification of the ash was conducted at a temperature of 1400 degrees C in order to generate a stable silicate slag, and the formed slag was examined with chemical and mineralogical analyses. The effect of vitrification on the leaching characteristics of various elements in the ash was evaluated with acid leaching. The study shows that the boiler ash as a heterogeneous fine powder contains mainly silicate, carbonate, sulfates, chlorides, and residues of organic materials and heavy metal compounds. At elevated temperatures, the boiler ash goes through the initial moisture removal, volatilization, decomposition, sintering, melting, and slag formation. At 1400 degrees C a thin layer of salt melt and a homogeneous glassy slag was formed. The experimental results indicate that leaching values of the vitrified slag are significantly reduced compared to the original boiler ash, and the vitrification could be an interesting alternative for a safer disposal of the boiler ash. Ash compacting, e.g., pelletizing can reduce volatilization and weight loss by about 50%, and would be a good option for the feed preparation before vitrification. PMID:18077086

  5. Dating base flow in streams using dissolved gases and diurnal temperature changes

    Science.gov (United States)

    Sanford, Ward E.; Casile, Gerolamo; Haase, Karl B.

    2015-12-01

    A method is presented for using dissolved CFCs or SF6 to estimate the apparent age of stream base flow by indirectly estimating the mean concentration of the tracer in the inflowing groundwater. The mean value is estimated simultaneously with the mean residence times of the gas and water in the stream by sampling the stream for one or both age tracers, along with dissolved nitrogen and argon at a single location over a period of approximately 12-14 h. The data are fitted to an equation representing the temporal in-stream gas exchange as it responds to the diurnal temperature fluctuation. The efficacy of the method is demonstrated by collecting and analyzing samples at six different stream locations across parts of northern Virginia, USA. The studied streams drain watersheds with areas of between 2 and 122 km2 during periods when the diurnal stream temperature ranged between 2 and 5°C. The method has the advantage of estimating the mean groundwater residence time of discharge from the watershed to the stream without the need for the collection of groundwater infiltrating to streambeds or local groundwater sampled from shallow observation wells near the stream.

  6. Numerical study on the fluid flow pass a square cylinder: The temperature-viscosity dependence

    Science.gov (United States)

    Lu, Jianhua; Li, Sheng; Guo, Zhaoli; Shi, Baochang

    2014-10-01

    In this paper, the 2D fluid flow pass a heated/cooled square cylinder exposed to a constant free-stream upward velocity is simulated via a multiple relaxation time (MRT) lattice-Boltzmann (LB) method. The buoyancy effect on the drag and lift coefficients as well as Nusselt number related is compared with the results in the existing literatures to validate the code used. The effect of temperature-viscosity dependence is then investigated to test whether the effect can be neglected or not for the mixed convection case. It is shown that the effect cannot be ignored when |Ri| > 0.15. Fortunately, the effect can be captured by using an effective temperature formula [J. M. Shi, D. Ferlach, M. Breuer, G. Biswas and F. Durst, Phys. Fluids16, 4331 (2004)] in a rather large range of Ri. All the numerical results, from another angle, also demonstrate that the MRT method is an efficient tool in simulating the problems such as the present one.

  7. Natural Convection Flow along an Isothermal Vertical Flat Plate with Temperature Dependent Viscosity and Heat Generation

    Directory of Open Access Journals (Sweden)

    Md. Mamun Molla

    2014-01-01

    Full Text Available The purpose of this study is to investigate the natural convection laminar flow along an isothermal vertical flat plate immersed in a fluid with viscosity which is the exponential function of fluid temperature in presence of internal heat generation. The governing boundary layer equations are transformed into a nondimensional form and the resulting nonlinear system of partial differential equations is reduced to a convenient form which are solved numerically using an efficient marching order implicit finite difference method with double sweep technique. Numerical results are presented in terms of the velocity and temperature distribution of the fluid as well as the heat transfer characteristics, namely, the wall shear stress and the local and average rate of heat transfer in terms of the local skin-friction coefficient, the local and average Nusselt number for a wide range of the viscosity-variation parameter, heat generation parameter, and the Rayleigh number. Increasing viscosity variation parameter and Rayleigh number lead to increasing the local and average Nusselt number and decreasing the wall shear stress. Wall shear stress and the rate of heat transfer decreased due to the increase of heat generation.

  8. Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device

    Directory of Open Access Journals (Sweden)

    Wilson Thomas S

    2009-12-01

    Full Text Available Abstract Background Interventional medical devices based on thermally responsive shape memory polymer (SMP are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. Methods A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Results Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Conclusions Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

  9. Ash properties of some dominant Greek forest species

    International Nuclear Information System (INIS)

    The elemental and chemical wood ash compositions of six dominant Greek fuels was investigated using a variety of techniques, including thermal gravimetric analysis (TG), differential thermal analysis (DTA), atomic absorption spectroscopy (AAS) and X-ray diffraction (XRD). In addition, the alkalinity of wood ash was determined by titration. The ash was prepared by combustion at low (600 deg. C), middle (800 deg. C) and high temperatures (1000 deg. C). The ash composition is very important because thousands of hectares of wildlands are burned annually in Greece. The resulting deposits affect soil properties (i.e., pH) and provide a source of inorganic constituents (i.e., Ca, K, Na, Mg, etc.), while the most soluble compounds (i.e., sodium and potassium hydroxides and carbonates) do not persist through the wet season. The samples selected were: Pinus halepensis (Aleppo pine), Pinus brutia (Calabrian pine), Olea europaea (Olive), Cupressus sempervirens (Italian cypress), Pistacia lentiscus (Mastic tree), Quercus coccifera (Holly oak)

  10. [Study on mercury re-emissions during fly ash utilization].

    Science.gov (United States)

    Meng, Yang; Wang, Shu-Xiao

    2012-09-01

    The amount of fly ash produced during coal combustion is around 400 million tons per year in China. About 65%-68% of fly ash is used in building material production, road construction, architecture and agriculture. Some of these utilization processes include high temperature procedures, which may lead to mercury re-emissions. In this study, experiments were designed to simulate the key process in cement production and steam-cured brick production. A temperature programmed desorption (TPD) method was used to study the mercury transformation in the major utilization processes. Mercury re-emission during the fly ash utilization in China was estimated based on the experimental results. It was found that mercury existed as HgCl2 (Hg2 Cl2), HgS and HgO in the fly ash. During the cement production process, more than 98% of the mercury in fly ash was re-emitted. In the steam-curing brick manufacturing process, the average mercury re-emission percentage was about 28%, which was dominated by the percentage of HgCl2 (Hg2 Cl2). It is estimated that the mercury re-emission during the fly ash utilization have increased from 4.07 t in 2002 to 9.18 t in 2008, of which cement industry contributes about 96.6%. PMID:23243850

  11. Reducing carbon-in-ash

    Energy Technology Data Exchange (ETDEWEB)

    Nigel S. Dong [IEA Clean Coal Centre, London (United Kingdom)

    2010-05-15

    High levels of carbon-in-ash lead to reduced power plant efficiency and higher fuel costs, degrade the performance of electrostatic precipitators and increase emissions of particulates. Increased carbon levels in the fly ash can lead to problems with ash use in cement/concrete production. This report reviews current measures and technologies that can be used to prevent excessive carbon-in-ash in pulverised coal combustion (PCC) power plants. These include coal cleaning, coal fineness improvement, reduction of distribution imbalance of coal among burners, increasing coal-air mixing rates at both burner and OFA levels and optimising excess air ratios. A plasma-assisted combustion enhancement technology can help achieve better ignition and more stable flame for coals that are normally difficult to burn. Computer-based combustion optimisation using expert systems, neural network systems and coal combustion simulation is becoming an invaluable means to tackle the carbon-in-ash issue. This report also reviews the regulations in nine major coal-consuming countries, which stipulate the maximum unburnt carbon levels permitted for fly ash for use in concrete/cement production. The Loss on Ignition (LOI) parameter is used in all national standards, although it is considered inadequate and may exclude some usable fly ash from being utilised. Performance-based regulations are more appropriate and have been adopted by Canada and USA. The EU and Canada now permit the use of fly ash produced from co-combustion of coal and biomass. China and Russia allow very high LOI levels for certain fly ash but the other countries require similar LOI limits for fly ash for use in concrete. Finally, this report discusses measures and technologies for reduction of carbon-in-ash, including classification, froth flotation, triboelectrostatic separators, thermal processes and carbon surface modification. 146 refs., 19 figs., 15 tabs.

  12. TOPLYR-2, Open Channel H2O Flow Temperature, Distant Source, Time-Dependent Boundary Conditions

    International Nuclear Information System (INIS)

    1 - Description of problem or function: TOPLYR2 applies the first law of thermodynamics to compute the temperature of a water mass flowing in an open channel. The program is designed to accommodate variable depth, velocity, and cross section. The source of energy (location of the discharge) is assumed to be sufficiently distant from the river segment under examination that the momentum associated with the discharge is insignificant. Velocity distribution at both the inlet and outlet of the reach as well as the temperature distribution at the inlet as a function of time and at the outlet initially are specified. Eddy diffusivities, ambient meteorological conditions, and geometry are also supplied to the code. Although the lateral eddy diffusivity is allowed to vary spatially, the effect of density disparity is not treated explicitly by the code. Temporal behavior induced by variations in the ambient meteorological and boundary conditions are computed. 2 - Method of solution: TOPLYR2 divides the water mass into an array of rectangular prisms of non-uniform depth where vertically averaged quantities are employed. The mathematical model employs an energy balance of temporal, convective, diffusional and source terms and a mass balance. The equations are transformed to a second-order finite-difference form and an alternating direction implicit scheme is used to compute the temperature field. The two-dimensional tridiagonal arrays produced by the ADI method are solved by Gaussian elimination. Provisions have been included in the program to accommodate non-uniform diffusivity. The energy source results from weather conditions and Newton's cooling law boundary conditions. 3 - Restrictions on the complexity of the problem: Subscripted variables are dimensioned at compilation time using the UNIVAC1108 procedure definition processor. Code instructions require relatively little storage. A typical river simulation problem with adequate geometric-time mesh involves about 10

  13. The late Pleistocene ground surface temperature and corrected heat flow density for northern part of Poland

    Science.gov (United States)

    Szewczyk, J.; Gientka, D.

    2003-04-01

    Paleoclimatic ground surface temperature (GST) changes in last 100 ka years are a major factor causing vertical variation of terrestrial heat flow density (HFD). The value of this parameter important for thermal and rheological modelling may be considerably influenced by paleoclimatic factor and should be corrected for this reason. Very important criteria for studying paleoclimatic events on boreholes is the knowledge of depth distribution of thermal conductivity. However, core samples from majority of deep boreholes are hardly available and laboratory measurements of thermal conductivity are very scarce and sometimes not confident. We used a method of estimating the thermal conductivity from well logging data interpretation. The thermal conductivity was calculated using volumetric model of rock with mean geometric formula. The synthetic temperature logs (T_s) based on this data are an "active" method of investigation of vertical variation of HFD and GST determination. For a majority of deep boreholes in Polish Lowlands in uppermost part (GST in the Late Pleistocene for the representative data for 59 deep boreholes for the N of Poland. The GST was -5.17 +/- 5.45^oC. The observed big scatter of presented results seems to be consequence of unstable thermal conditions and bad calibration of old temperature logs. The amplitude of post glacial warming (ΔGST) is not less then +13.1^oC. The history of climate for the last 500 ka years shows that this time was spent mainly in ice age and this is "normal" state of HFD. The presented method of investigations seems to be very effective for determination of HFD for this condition.

  14. Computational fluid dynamics (CFD) investigation of air flow and temperature distribution in a small scale bread-baking oven

    International Nuclear Information System (INIS)

    Experimental and computational fluid dynamics (CFD) analyses of the thermal air flow distribution in a 3-zone small scale forced convection bread-baking oven are undertaken. Following industrial bread-making practise, the oven is controlled at different (constant) temperatures within each zone and a CFD model is developed and validated against experimental data collected within the oven. The CFD results demonstrate that careful selection of the flow model, together with implementation of realistic boundary conditions, give accurate temperature predictions throughout the oven. The CFD model is used to predict the flow and thermal fields within the oven and to show how key features, such as regions of recirculating flow, depend on the speeds of the impinging jets.

  15. Measurement of natural activity in peat ashes

    International Nuclear Information System (INIS)

    High proportions of radioactive materials in peat ashes may involve radiation hazards during handling and deposition of these waste materials. Measurements have been performed to determine the content of radioactive materials in ashes from peat burning. The activities in fly ash and ''solid'' ash in seven peat-fired power plants in Sweden are presented. The methods of analysing and measuring peat ashes for activity from different radionuclides are described. The activity levels in ash samples are given

  16. BUS 611 Ash course tutorial / uophelp

    OpenAIRE

    uophelp

    2015-01-01

    For more course tutorials visit www.uophelp.com   BUS 611 Week 1 Assignment Article Review (Ash Course) BUS 611 Week 2 Assignment Project Risk (Ash Course) BUS 611 Week 3 Assignment WBS (Ash Course) BUS 611 Week 4 Assignment Integrated Project Management Tools (Ash Course) BUS 611 Week 5 Assignment Monthly Status Reports (Ash Course) BUS 611 Week 6 Final Research Paper (Ash Course)  

  17. Can pore-clogging by ash explain post-fire runoff?

    Science.gov (United States)

    Stoof, Cathelijne R.; Gevaert, Anouk I.; Baver, Christine; Hassanpour, Bahareh; Morales, Veronica L.; Zhang, Wei; Martin, Deborah; Giri, Shree K.; Steenhuis, Tammo S.

    2016-01-01

    Ash plays an important role in controlling runoff and erosion processes after wildfire and has frequently been hypothesised to clog soil pores and reduce infiltration. Yet evidence for clogging is incomplete, as research has focussed on identifying the presence of ash in soil; the actual flow processes remain unknown. We conducted laboratory infiltration experiments coupled with microscope observations in pure sands, saturated hydraulic conductivity analysis, and interaction energy calculations, to test whether ash can clog pores (i.e. block pores such that infiltration is hampered and ponding occurs). Although results confirmed previous observations of ash washing into pores, clogging was not observed in the pure sands tested, nor were conditions found for which this does occur. Clogging by means of strong attachment of ash to sand was deemed unlikely given the negative surface charge of the two materials. Ponding due to washing in of ash was also considered improbable given the high saturated conductivity of pure ash and ash–sand mixtures. This first mechanistic step towards analysing ash transport and attachment processes in field soils therefore suggests that pore clogging by ash is unlikely to occur in sands. Discussion is provided on other mechanisms by which ash can affect post-fire hydrology.

  18. THE COMPRESSIVE AND FLEXURAL STRENGTHS OF SELF-COMPACTING CONCRETE USING RAW RICE HUSK ASH

    Directory of Open Access Journals (Sweden)

    MD NOR ATAN

    2011-12-01

    Full Text Available This study investigates the compressive and flexural strengths of self-compacting concrete incorporating raw rice husk ash, individually and in combination with other types of mineral additives, as partial cement replacement. The additives paired with raw rice husk ash were fine limestone powder, pulverized fuel ash and silica fumes. The mix design was based on the rational method where solid constituents were fixed while water and superplasticizer contents were adjusted to produce optimum viscosity and flowability. All mixes were designed to achieve SF1 class slump-flow with conformity criteria ≥ 520 mm and ≤ 700 mm. Test results show that 15% replacement of cement using raw rice husk ash produced grade 40 concrete. It was also revealed that 30% and 45% cement replacements using raw rice husk ash combined with limestone powder and raw rice husk ash combined with limestone powder and silica fume respectively, produced comparable compressive strength to normal concrete and improved flexural strengths.

  19. Peak river flows in cold regions – Drivers and modelling using GRACE satellite observations and temperature data

    OpenAIRE

    Wang, Shusen; Zhou, Fuqun; Russell, Hazen A. J.; Huang, Ran; Shen, Yanjun

    2016-01-01

    The peak river flow for the Mackenzie River is modelled using GRACE satellite observations and temperature data, which advances the applications of space-based time-variable gravity measurements in cold region flood forecasting. The model estimates peak river flow by simulating peak surface runoff from snowmelt and the corresponding baseflow. The modelled results compared fairly well with the observed values at a downstream hydrometric station. The results also revealed an average 22-day trav...

  20. ECO 316(ASH) course tutorial/tutorialoutlet

    OpenAIRE

    naresh 1

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   ECO 316 Week 1 DQ 1 Should You Invest Short Term (Ash) ECO 316 Week 1 DQ 2 Treasury Inflation Protection Bonds (Ash) ECO 316 Week 1 Quiz (Chapter 1-6) (Ash) ECO 316 Week 2 DQ 1 New Product, Will I Be Rich (Ash) ECO 316 Week 2 DQ 2 Mutual Fund Regulation (Ash) ECO 316 Week 2 Quiz (Chapter 7-12) (Ash) ECO 316 Week 3 DQ 1 Exchange Rate Risk (Ash) ECO 316 Week 3 DQ 2 Should I Expect a Bail Out (Ash) ...